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Sample records for human intervertebral disk

  1. Elastin in the human intervertebral disk. A histological and biochemical study comparing it with elastin in the human yellow ligament.

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    Mikawa, Y; Hamagami, H; Shikata, J; Yamamuro, T

    1986-01-01

    The elastic fiber and elastin in the human yellow ligament and intervertebral disk were studied histologically and biochemically. The elastic fiber in the human intervertebral disk, which until now had not been clearly identified microscopically, was observed clearly. We found the distribution of the elastic fiber in the intervertebral disk to be very sparse and irregular, and its diameter was small, being about one-tenth of that found in the yellow ligament. The elastin contents of the yellow ligament and intervertebral disk were 46.7% +/- 0.9% and 1.7% +/- 0.2% respectively (mean +/- SE) of the total dry weight. The amino acid composition of elastin in the yellow ligament is similar to that of other tissue, as reported in the literature; however, that found in the intervertebral disk is significantly different. It would appear, therefore, that the elastin in the intervertebral disk is of a different type from that found elsewhere.

  2. Molecular Imaging Agents Specific for the Annulus Fibrosus of the Intervertebral Disk

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    Summer L. Gibbs-Strauss

    2010-05-01

    Full Text Available Low back pain is a prevalent medical condition that is difficult to diagnose and treat. Current imaging methods are unable to correlate pain reliably with spinal structures, and surgical removal of painful damaged or degenerating disks is technically challenging. A contrast agent specific for the intervertebral disk could assist in the detection, diagnosis, and surgical treatment of low back pain. The styryl pyridinium (FM fluorophores were characterized and structure-activity relationships between chemical structure and in vivo uptake were established. Two novel FM fluorophores with improved optical properties for imaging the intervertebral disks were synthesized and evaluated in mice, rats, and pigs. After a single systemic injection, eight of eight FM fluorophores provided high-contrast imaging of the trigeminal ganglia, whereas six of eight provided high-contrast imaging of the dorsal root ganglia. Unexpectedly, three of eight FM fluorophores provided high-contrast imaging of annulus fibrosus tissue of the intervertebral disks, confirmed histologically. We present the first known contrast agent specific for the intervertebral disks and identify the chemical structural motif that mediates uptake. FM fluorophores could be used for image-guided surgery to assist in the removal of intervertebral disk and lay the foundation for derivatives for magnetic resonance imaging and positron emission tomography.

  3. [Expression and distribution of xenoantigen alpha-Gal in intervertebral disk of Chinese banna minipig inbred line].

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    Shou, Jian-guo; Mi, Jian-hong; Ying, Da-jun

    2002-09-01

    To investigate the expression and distribution of xenoantigen in intervertebral disk of Chinese banna minipig inbred line, and to study the availability of xenograft transplantation of intervertebral disk. Samples of intervertebral disk were collected from six Banna pigs of 8 to 11-month-old. The fixation, embedment and slice were performed. alpha-Gal specific binding lection (BSI-B4) were used as affinity reagents and affinity-immunohistochemistry assays (SABC methods and DAB stain) were conducted to detect the expression and distribution of xenoantigen (alpha-Gal). alpha-Gal was found in chondrocyte cell and chondrocyte-like cell in intervertebral disk which have the positive yellow-stained particulate aggradation. There was no stain in the matrix, elastic fiber and collagen fiber. The distribution of xenoantigen is locally in the tissue of intervertebral disk and its expression is weak. This suggests that the intervertebral disk of Banna pig may be alternative donor for xenotransplantation.

  4. Intervertebral disk prolapse in a ferret.

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    Morera, Neus; Valls, Xavier; Mascort, Joan

    2006-09-01

    This case report describes the diagnosis and resolution of an inter-vertebral disk prolapse in a 6-year-old ferret. No predisposing causes were found in the patient's history. A right hemilaminectomy, performed 1 week after presentation, was chosen to treat the patient surgically, and complete remission of clinical signs was achieved 2 months after presentation.

  5. CT-guided intradiscal ozone injection combined with intervertebral facet joint steroid injection for lumbar disk herniation accompanied with intervertebral arthritis

    International Nuclear Information System (INIS)

    Zhang Li; Chen Zhaohui; Sun Xijun; Liu Jianping; Li Jiakai

    2009-01-01

    Objective: To compare the clinical effectiveness of ozone (O 3 ) nucleus pulposus ablation only with that of O 3 nucleus pulposus ablation combined with intervertebral facet joint injection of compound Betamethasome in treating lumbar disk herniation accompanied with intervertebral facet arthritis. Methods: Eighty patients with lumbar disk herniation and intervertebral facet arthritis were equally and randomly divided into two groups. Under CT guidance, O 3 nucleus pulposus ablation was performed in patients of group A(n=40), while O 3 nucleus pulposus ablation combined with intervertebral facet joint injection of compound Betamethasome (0.5-1 ml) was carried out in patients of group B(n=40). Using double blind method the therapeutic effectiveness was evaluated before and 1 week,3,6-months after the procedure by an Oswestry Low Back Pain Disability Questionnaire. Results: One week after the procedure the effective rate of group A and group B was 65% and 82.5% respectively. Three and six months after the treatment, the effective rate was 75% and 70% respectively for group A, while it was 90% and 92.5% respectively for group B. The difference between two groups was significant (P 3 combined with intervertebral facet joint injection of compound Betamethasome is an effective and safe treatment for lumbar disk herniation accompanied with intervertebral facet arthritis.It is worth popularizing this technique in clinical practice. (authors)

  6. Molecular signaling in intervertebral disk development.

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    DiPaola, Christian P; Farmer, James C; Manova, Katia; Niswander, Lee A

    2005-09-01

    The purpose of this investigation is to identify and study the expression pattern of pertinent molecular factors involved in the differentiation of the intervertebral disk (IVD). It is likely that hedgehog genes and the BMP inhibitors are key factors involved in spinal joint formation. Radioactive in situ hybridization with mRNA probes for pax-1, SHH, IHH and Noggin gene was performed on mouse embryo and adult tissue. Immunohistochemistry was performed to localize hedgehog receptor, "patched" (ptc). From 14.5 dpc until birth pax-1 mRNA was expressed in the developing anulus fibrosus (AF). During the same developmental period Noggin mRNA is highly expressed throughout the spine, in the developing AF, while ptc protein and SHH mRNA were expressed in the developing nucleus pulposus (NP). IHH mRNA was expressed by condensing chondrocytes of the vertebral bodies and later becomes confined to the vertebral endplate. We show for the first time that pax-1 is expressed in the adult intervertebral disk. Ptc expression in the NP is an indicator of hedgehog protein signaling in the developing IVD. The expression pattern of the BMP inhibitor Noggin appears to be important for the normal formation of the IVD and may prove to play a role in its segmental pattern formation.

  7. Effects of C5/C6 Intervertebral Space Distraction Height on Pressure on the Adjacent Intervertebral Disks and Articular Processes and Cervical Vertebrae Range of Motion.

    Science.gov (United States)

    Lu, Tingsheng; Luo, Chunshan; Ouyang, Beiping; Chen, Qiling; Deng, Zhongliang

    2018-04-25

    BACKGROUND This study aimed to investigate the association between range of motion of the cervical vertebrae and various C5/C6 intervertebral space distraction heights. MATERIAL AND METHODS The cervical vertebrae from 6 fresh adult human cadavers were used to prepare the models. Changes in C4/C5 and C6/C7 intervertebral disk pressures, articular process pressure, and range of motion of the cervical vertebrae before and after the distraction of the C5/C6 intervertebral space at benchmark heights of 100%, 120%, 140%, and 160% were tested under different exercise loads. RESULTS The pressure on the adjacent intervertebral disks was highest with the standing upright position before distraction, varied with different positions of the specimens and distraction heights after distraction, and was closest to that before distraction at a distraction height of 120% (Particular processes was highest with left and right rotations before distraction, varied with different positions of the specimens and distraction heights after distraction, and was lowest under the same exercise load with different positions at a distraction height of 120% (Pdistraction and at a distraction height of 120% after distraction, respectively (Particular processes and range of motion of the cervical vertebrae and is therefore an appropriate intervertebral space distraction height.

  8. Contrast myelography in the diagnosis of posterior hernias of lumbar intervertebral disks

    International Nuclear Information System (INIS)

    Maratkanova, T.V.; Morozova, T.D.

    1997-01-01

    Based on the analysis of the results of 297 contrast myelographies (MG) by means of water soluble agents made in patients with posterior hernias of lumbar intervertebral disks (PHLID), the authors define the potentialities of this technique in the diagnosis of PHLID. Additionally, two oblique X-ray films have been included into the exicting filming routine, which may detect all specific features of intervertebral disk damage at MG. The authors make additions into the wellknown myelographic symptomatology of PHLID, by outlining the abnormal anterior configuration of a contrast column at the level of a diseased disk in PHLID at the foraminal site. The findings suggest that contrast MG with nonionic water-soluble agents is a rather effective technique in the diagnosis of PHLID

  9. [Total cervical disk replacement--implant-specific approaches: keel implant (Prodisc-C intervertebral disk prosthesis)].

    Science.gov (United States)

    Korge, Andreas; Siepe, Christoph J; Heider, Franziska; Mayer, H Michael

    2010-11-01

    Dynamic intervertebral support of the cervical spine via an anterolateral approach using a modular artificial disk prosthesis with end-plate fixation by central keel fixation. Cervical median or mediolateral disk herniations, symptomatic cervical disk disease (SCDD) with anterior osseous, ligamentous and/or discogenic narrowing of the spinal canal. Cervical fractures, tumors, osteoporosis, arthrogenic neck pain, severe facet degeneration, increased segmental instability, ossification of posterior longitudinal ligament (OPLL), severe osteopenia, acute and chronic systemic, spinal or local infections, systemic and metabolic diseases, known implant allergy, pregnancy, severe adiposity (body mass index > 36 kg/m2), reduced patient compliance, alcohol abuse, drug abuse and dependency. Exposure of the anterior cervical spine using the minimally invasive anterolateral approach. Intervertebral fixation of retainer screws. Intervertebral diskectomy. Segmental distraction with vertebral body retainer and vertebral distractor. Removal of end-plate cartilage. Microscopically assisted decompression of spinal canal. Insertion of trial implant to determine appropriate implant size, height and position. After biplanar image intensifier control, drilling for keel preparation using drill guide and drill bit, keel-cut cleaner to remove bone material from the keel cut, radiologic control of depth of the keel cut using the corresponding position gauge. Implantation of original implant under lateral image intensifier control. Removal of implant inserter. Functional postoperative care and mobilization without external support, brace not used routinely, soft brace possible for 14 days due to postoperative pain syndromes. Implantation of 100 cervical Prodisc-C disk prostheses in 78 patients (average age 48 years) at a single center. Clinical and radiologic follow-up 24 months postoperatively. Significant improvement based on visual analog scale and Neck Disability Index. Radiologic

  10. Magnetic resonance imaging of lumbar intervertebral disks with its pathological cerrelation

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    Kakitsubata, Yousuke; Nabeshima, Kazuki; Kihara, Yasushi; Harada, Kuniko; Mori, Yukiko; Kakitsubata, Sachiko; Watanabe, Katsushi

    1988-02-01

    Three cadaver spines were examined by magnetic resonance imaging (MRI) with 0.1 tesla resistive magnet. Anatomic sections of lumbar intervertebral disks were compared with various MR images, saturation recovery (SR), inversion recovery (IR), T1 and T2 weighted spin echo (SE) images. And the signal intensity of degenerated disks on T2 weighted images were correlated with the histological studies. The disks were well delineated by SR and their degenerative changes were detected most sensitively by T2 weighted SE image. Two parts of disk were delineated on T2 weighted SE image. The central portion of disk showed high signal intensity and the periphery a low signal intensity. The central high signal intensity area corresponded to the combination of annulus fibrosus and nucleus pulposus, which cannot be differenciated by MR. And the peripheral low signal intensity area corresponded to the collagenous fibers of annulus fibrosus. Histologically, disks with decreased signal intensity had marked increase of collagen fibers. The intranuclear cleft were evident on T2 weighted image, and the corresponding structures thought to be caused by invagination of the lamellae of the annulus into the nucleus in the histological specimens. MRI were useful modality for evaluation of intervertebral disks, but biochemical analysis may be needed for precise interpretation of MR images of disks in addition to histological studies.

  11. Evaluation of Water Retention in Lumbar Intervertebral Disks Before and After Exercise Stress With T2 Mapping.

    Science.gov (United States)

    Chokan, Kou; Murakami, Hideki; Endo, Hirooki; Mimata, Yoshikuni; Yamabe, Daisuke; Tsukimura, Itsuko; Oikawa, Ryosuke; Doita, Minoru

    2016-04-01

    T2 mapping was used to quantify moisture content of the lumbar spinal disk nucleus pulposus (NP) and annulus fibrosus before and after exercise stress, and after rest, to evaluate the intervertebral disk function. To clarify water retention in intervertebral disks of the lumbar vertebrae by performing magnetic resonance imaging before and after exercise stress and quantitatively measuring changes in moisture content of intervertebral disks with T2 mapping. To date, a few case studies describe functional evaluation of articular cartilage with T2 mapping; however, T2 mapping to the functional evaluation of intervertebral disks has rarely been applied. Using T2 mapping might help detect changes in the moisture content of intervertebral disks, including articular cartilage, before and after exercise stress, thus enabling the evaluation of changes in water retention shock absorber function. Subjects, comprising 40 healthy individuals (males: 26, females: 14), underwent magnetic resonance imaging T2 mapping before and after exercise stress and after rest. Image J image analysis software was then used to set regions of interest in the obtained images of the anterior annulus fibrosus, posterior annulus fibrosus, and NP. T2 values were measured and compared according to upper vertebrae position and degeneration grade. T2 values significantly decreased in the NP after exercise stress and significantly increased after rest. According to upper vertebrae position, in all of the upper vertebrae positions, T2 values for the NP significantly decreased after exercise stress and significantly increased after rest. According to the degeneration grade, in the NP of grade 1 and 2 cases, T2 values significantly decreased after exercise stress and significantly increased after rest. T2 mapping could be used to not only diagnose the degree of degeneration but also evaluate intervertebral disk function. 3.

  12. Correlation between T2 relaxation time and intervertebral disk degeneration

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    Takashima, Hiroyuki; Takebayashi, Tsuneo; Yoshimoto, Mitsunori; Terashima, Yoshinori; Tsuda, Hajime; Ida, Kazunori; Yamashita, Toshihiko [Sapporo Medical University, Department of Orthopedic Surgery, School of Medicine, Sapporo, Hokkaido (Japan)

    2012-02-15

    Magnetic resonance T2 mapping allows for the quantification of water and proteoglycan content within tissues and can be used to detect early cartilage abnormalities as well as to track the response to therapy. The goal of the present study was to use T2 mapping to quantify intervertebral disk water content according to the Pfirrmann classification. This study involved 60 subjects who underwent lumbar magnetic resonance imaging (a total of 300 lumbar disks). The degree of disk degeneration was assessed in the midsagittal section on T2-weighted images according to the Pfirrmann classification (grades I to V). Receiver operating characteristic (ROC) analysis was performed among grades to determine the cut-off values. In the nucleus pulposus, T2 values tended to decrease with increasing grade, and there was a significant difference in T2 values between each grade from grades I to IV. However, there was no significant difference in T2 values in the anterior or posterior annulus fibrosus. T2 values according to disk degeneration level classification were as follows: grade I (>116.8 ms), grade II (92.7-116.7 ms), grade III (72.1-92.6 ms), grade IV (<72.0 ms). T2 values decreased with increasing Pfirrmann classification grade in the nucleus pulposus, likely reflecting a decrease in proteoglycan and water content. Thus, T2 value-based measurements of intervertebral disk water content may be useful for future clinical research on degenerative disk diseases. (orig.)

  13. Lumber intervertebral disk; Correlation with the signal intensity of magnetic resonance imaging and the histological changes

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    Uchida, Ryusei; Takahashi, Sadao; Ando, Tadashi; Kumano, Kiyoshi; Hiranuma, Kenji; Kanazawa, Yousuke; Konishi, Seiji; Eguchi, Masanobu; Tanioka, Hisaya (KantoRosai Hospital, Kawasaki, Kanagawa (Japan))

    1989-11-01

    We studied to provide precise correlations between the intensity of MRI signals and the degenerative changes of the nucleus pulposes of the L4/5 intervertebral disk herniations. 23 cases with the L4/5 intervertebral disk herniations having surgical treatment were examined using Magnetom H 15 (1.5 tesla) with surface coil. The images were obtained with T2 images (long TR (1000{approx}1600 msec), TE (60{approx}90 msec)). The intensity was measured using FUJI densitometer FD 101 at the lumber vertebral body and the intervertebral disk. We calculated the L4/5 intervertebral disk degeneration ratio (determined by comparing the modified L4/5 MR signal intensity with the modified L2/3 MR signal itensity). Histological changes were examined in the cellular components of the nucleus pulposus (such as the number of the nucleus cells, nucleus cell nesting and HE stainability of the nucleus cell) and the matrics substance (such as fibrillation, hyaline degeneration and granular degeneration). Histochemical studies were performed using Scott's Method (AB-0.4 M MgCl{sub 2} Alcinophilia, AB-09 M, MgCl{sub 2} Alcinophilia) to investigate glycosaminoglycans of the nucleus pulposus. We compared the histological and histochemical changes with the MR L4/5 intervetebral disk degeneration ratio. The decreasing MRI signal intensity of the nucleous pulposus was (1) corresponded to the pathological changes such as the increasing number of the cell nesting, fibrillation and hyaline degeneration of the nucleus polposus. (2) corresponded to the decrease in the total glycosaminoglycans of the nucleus pulposus. (3) corresponded to the early stage of degeneration of the nucleus polposus, but in aging when all levels of intervertebral disk degeneration appeared, we could not know the degree of the disk degeneration from the signal intensity of MRI. (J.P.N.).

  14. Computerized tomography of the lumbar vertebral column after intervertebral disk operation. Pt. 1

    International Nuclear Information System (INIS)

    Schindler, G.; Klott, K.

    1984-01-01

    Problems after intervertebral disk operations are to be expected in about 25-40% of the patients operated. Progressive degnerative alterations at the disks, the vertebrae and the intervertebral joints entail chronic mechanical pain resulting from the sensitive innervation of the structures mentioned, or lead in severe cases to the alteration of the epidural space respectively the spinal nerves with corresponding peripheral neurological symptoms. As post-surgical complications spondylodiscitis, spondylitis, haematomae, liquor fistulae, and split-off bone fragments can be the cause of complaints, for which computerized tomography is a better diagnostical method than myelography. (BWU) [de

  15. Cervical intervertebral disk herniation in chondrodystrophoid and nonchondrodystrophoid small-breed dogs: 187 cases (1993-2013).

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    Hakozaki, Takaharu; Iwata, Munetaka; Kanno, Nobuo; Harada, Yasuji; Yogo, Takuya; Tagawa, Masahiro; Hara, Yasushi

    2015-12-15

    To identify characteristics of chondrodystrophoid and nonchondrodystrophoid small-breed dogs with cervical intervertebral disk herniation (IVDH). Retrospective case series. 187 small-breed (≤ 15 kg [33 lb]) dogs that underwent surgery because of cervical IVDH. Medical records were reviewed for information on breed, sex, age, weight, location of affected intervertebral disks, duration and severity of neurologic signs, and recovery time. 55 of the 187 (29.4%) dogs were Beagles. The most frequently affected intervertebral disk was C2-3 (81/253 [32.0%]), and this was the more frequently affected intervertebral disk in dogs of several chondrodystrophoid breeds, including Beagles (29/66 [43.9%]), Dachshunds (13/37 [35.1%]), Shih Tzus (16/41 [39.0%]), and Pekingese (3/10 [30.0%]). However, caudal disks (C5-6 or C6-7) were more frequently affected in Yorkshire Terriers (13/24 [54.2%]) and Chihuahuas (9/13 [69%]). Shih Tzus and Yorkshire Terriers were significantly older at the time of surgery (mean ± SD age, 9.6 ± 2.3 years and 9.5 ± 2.5 years, respectively) than were Pomeranians (6.2 ± 2.3 years), and Yorkshire Terriers had a significantly higher number of affected disks (2.0 ± 0.9) than did Dachshunds (1.1 ± 0.3). Mean recovery time was significantly longer in Yorkshire Terriers (36.7 ± 13.0 days) than in Beagles (16.5 ± 17.1 days), Shih Tzus (17.8 ± 14.5 days), or Chihuahuas (12.2 ± 7. 2 days). Results suggested that there may be breed-specific differences in the characteristics of cervical IVDH in small-breed dogs.

  16. Refinement of elastic, poroelastic, and osmotic tissue properties of intervertebral disks to analyze behavior in compression.

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    Stokes, Ian A F; Laible, Jeffrey P; Gardner-Morse, Mack G; Costi, John J; Iatridis, James C

    2011-01-01

    Intervertebral disks support compressive forces because of their elastic stiffness as well as the fluid pressures resulting from poroelasticity and the osmotic (swelling) effects. Analytical methods can quantify the relative contributions, but only if correct material properties are used. To identify appropriate tissue properties, an experimental study and finite element analytical simulation of poroelastic and osmotic behavior of intervertebral disks were combined to refine published values of disk and endplate properties to optimize model fit to experimental data. Experimentally, nine human intervertebral disks with adjacent hemi-vertebrae were immersed sequentially in saline baths having concentrations of 0.015, 0.15, and 1.5 M and the loss of compressive force at constant height (force relaxation) was recorded over several hours after equilibration to a 300-N compressive force. Amplitude and time constant terms in exponential force-time curve-fits for experimental and finite element analytical simulations were compared. These experiments and finite element analyses provided data dependent on poroelastic and osmotic properties of the disk tissues. The sensitivities of the model to alterations in tissue material properties were used to obtain refined values of five key material parameters. The relaxation of the force in the three bath concentrations was exponential in form, expressed as mean compressive force loss of 48.7, 55.0, and 140 N, respectively, with time constants of 1.73, 2.78, and 3.40 h. This behavior was analytically well represented by a model having poroelastic and osmotic tissue properties with published tissue properties adjusted by multiplying factors between 0.55 and 2.6. Force relaxation and time constants from the analytical simulations were most sensitive to values of fixed charge density and endplate porosity.

  17. Experimental chemonucleolysis with chymopapain in canine intervertebral disks

    International Nuclear Information System (INIS)

    Kudo, T.; Sumi, A.; Hashimoto, A.

    1993-01-01

    The present study describes the radiological and histological changes in the canine intervertebral disk after the experimental injection of chymopapain as the chemical reagent, and determines the appropriate dose of the enzyme for treatment of herniated disks. By radiography, narrowing of the disk space was observed within 2 weeks after the injection of chymopapain, and recovered to 74.1% in the 0.1 mg group, 61.1% in the 1.0 mg group and 71.7% in the 10.0 mg group at 12 weeks. The disk space recovery showed a tendency to delay with aging. Microscopically, proteoglycan positive matrix appeared and the nuclear space was reduced in each disk at 2 weeks after chymopapain injection. The nucleus pulposus contained an irregularly-defined mass consisting of clusters of degenerated notochordal cells surrounded by proliferated chondrocytes and collagen matrix. In each disk at 12 weeks after chymopapain injection, the center of the nucleus pulposus was replaced by fibrocartilage tissue. In the disk into which 10.0 mg chymopapain was injected, the nuclear space filled with dense fibrocartilage tissue without a regenerated matrix component and narrowing of the disk were maintained. It is suggested that canine chemonucleolysis with 10.0 mg of chymopapain reduces the interdiskal pressure. This treatment may therefore relieve the signs and symptoms of herniation of the nucleus pulposus, and may effect chemical disk decompression

  18. Validation of Triphasic Mixture Theory for a Mimic of Intervertebral Disk Tissue

    NARCIS (Netherlands)

    Oomens, C.W.J.; Heus, de H.J.; Huyghe, J.M.R.J.; Nelissen, J.G.L.; Janssen, J.D.

    1995-01-01

    This paper describes experimental studies an synthetic madel materials that mimic the mechanical behavior af intervertebral disk tissue. The results are used ta validate the triphasic mixture theory to describe soft charged hydrated materiais. Permeability and swelling pressure experiments were used

  19. Effect of intervertebral disk degeneration on spinal stenosis during magnetic resonance imaging with axial loading

    International Nuclear Information System (INIS)

    Ahn, Tae-Joon; Lee, Sang-Ho; Choi, Gun; Ahn, Yong; Liu, Wei-Chiang; Kim, Ho-Jin; Lee, Ho-Yeon

    2009-01-01

    Magnetic resonance (MR) imaging with axial loading can simulate the physiological standing state and disclose spinal stenosis undetected or underestimated in the conventional position. Intervertebral disk degeneration may be an important factor in spinal stenosis. This study investigated whether intervertebral disk degeneration increases spinal stenosis during axial loading. MR imaging with and without axial loading was obtained in 51 patients with neurogenic intermittent claudication and/or sciatica and reviewed retrospectively. The grade of disk degeneration was rated in four disk spaces from L2-3 to L5-S1. The dural sac cross-sectional area (DCSA) was measured on MR images taken in both conventional and axial loading positions, and the change in the DCSA was calculated. The effect of disk degeneration on the DCSA was statistically analyzed. Significant decreases in the DCSA occurred with grade 4 disk degeneration (mean±standard deviation, 20.1±14.1 mm 2 ), followed by grade 3 (18.3±15.1 mm 2 ) and grade 2 (8.9±13.1 mm 2 ). DCSA decreased considerably with increased severity of disk degeneration with axial loading, except for grade 5 disk degeneration. More accurate diagnosis of stenosis can be achieved using MR imaging with axial loading, especially if grade 2 to 4 disk degeneration is present. (author)

  20. Evaluation on vertebral endplate injury and adjacent intervertebral disk injury of patients with osteoporotic vertebral compression fractures by MRI and its clinical significance

    International Nuclear Information System (INIS)

    Shen Yu; Shen Huiliang; Fang Xiutong; Zhang Wenbo

    2012-01-01

    Objective: To investigate the relationship between vertebral endplate injury and adjacent intervertebral disk injury of patients with acute or sub-acute osteoporotic vertebral compression fractures (OVC-F) by MRI, and to provide basis for diagnosis of OVCF. Methods: The clinical data of a total of 66 patients with OVCF underwent vertebroplasty (76 fracture of vertebral bodies) were selected. The vertebral endplate injury and adjacent intervertebral disk injury of OVCF patients were detected by MRI. Results: There were 57 vertebral endplate injury in 76 fracture vertebral bodies (75% ). There were only 27 vertebral bodies with vertebral endplate injury in 57 fracture vertebral bodies with endplate injury (47% ), and 22 vertebral with superior and inferior vertebral endplate injury (39% ), and 8 vertebral bodies with inferior vertebral endplate injury (14% ). There were 48 vertebral bodies with intervertebral disc injury in 76 fracture vertebral bodies (63% ). There were 22 intervertebral disc injury located above the fracture of the lumbar spine in 48 vertebral bodies with intervertebral disc injury (45% ), and 19 fracture vertebral bodies with upper and lower intervertebral disc injury (40% ), and 7 intervertebral injuries located below the fracture of the lumbar spine (15% ). Conclusion: Vertebral endplate injury is frequently associated with the adjacent intervertebral disk injury. The clinical diagnosis and treatment should be emphasized in the fracture vertebral endplate damage and adjacent intervertebral disc injury. (authors)

  1. THE INTERVERTEBRAL DISK PROTHESIS INSTALLATION AFTER ABLATION OF A DISK‘S HERNIA AT CERVICAL LEVEL

    Directory of Open Access Journals (Sweden)

    I.A.Norkin

    2008-12-01

    Full Text Available The purpose ofthe present work was to study the possibility of use the artificial disk «PRODISK» at cervical level after ablation of intervertebraldisk’s hernia. The basis of this research is complexexamination and surgical treatment of a 52-years-old-woman with osteochondrosis of cervical spine and with radiculopathy syndrome because of compression of spinal hernia roots of intervertebral disk On May, 29th, 2007 the patientwas operated: «diskectomyC6-C7' disk’s hernia removal, implantation of an artificial disk« PRODISK»at the level C6- C7». The patient became active on the third day after the operation, and she was discharged in eight days. Her neurologic symptoms regressed completely. Range of cervical motions was in the normal condition (flexia/anteflexia-35 °-40 °. The pain syndrome was arrested (VAS-2, VRS-1. We consider that any operation causes disorder of structural and functional properties and requires prosthetics of intervertebral disk’s, which can fully reconstruct biomechanical qualities of the operated segment

  2. [The possibilities for diagnostics of prescription of death coming based on the changes in the lumbar intervertebral disks (the comparison of the morphological, immunohistochemical and topographical findings)].

    Science.gov (United States)

    Byval'tsev, V A; Stepanov, I A; Semenov, A V; Perfil'ev, D V; Belykh, E G; Bardonova, L A; Nikiforov, S B; Sudakov, N P; Bespyatykh, I V; Antipina, S L

    The objective of the present study was the comprehensive analysis of the postmortem changes in the lumbar intervertebral disks within different periods after death. A total of seven vertebromotor segments were distinguished in the lumbosacral region of the vertebral column based on the examination of 7 corpses. All these segments were divided into three groups in accordance with the prescription of death coming as follows: up to 12 hours (group 1), between 12 and 24 hours (group 2), and between 24 and 36 hours (group 3) after death. The models of the segments thus obtained were subjected to the study by means of diffusion weighted MRI. The removed intervertebral disks were used for morphological and immunohistochemical investigations. The comparison of the diffusion coefficients (DI) revealed the significant difference between the intervertebral disks assigned to groups 1 and 2 (p<0.01). The number of the cells in the pulpal core, the vertebral end plate, and the fibrous ring in all the above groups of the intervertebral disks was significantly reduced (p<0.01). The analysis of the correlation dependence between cell density and diffusion coefficients has demonstrated the well apparent relationship between these characteristics of the intervertebral disks comprising groups 1 and 2. It is concluded that diffusion weighted MRI in the combination with the calculation of diffusion coefficients for the intervertebral disks provides a tool for diagnostics of prescription of death coming as confirmed by the results of the morphometric studies and immunohistochemical analysis.

  3. THE INTERVERTEBRAL DISK PROTHESIS INSTALLATION AFTER ABLATION OF A DISK‘S HERNIA AT CERVICAL LEVEL

    OpenAIRE

    I.A.Norkin; A.A.Chekhonatsky; I.I.Sholomov

    2008-01-01

    The purpose ofthe present work was to study the possibility of use the artificial disk «PRODISK» at cervical level after ablation of intervertebraldisk’s hernia. The basis of this research is complexexamination and surgical treatment of a 52-years-old-woman with osteochondrosis of cervical spine and with radiculopathy syndrome because of compression of spinal hernia roots of intervertebral disk On May, 29th, 2007 the patientwas operated: «diskectomyC6-C7' disk’s hernia removal, implantat...

  4. Changes in intervertebral disk dimensions after a loading task and the relationship with stature change measurements.

    Science.gov (United States)

    Lewis, Sandra E; Fowler, Neil E

    2009-10-01

    Lewis SE, Fowler NE. Changes in intervertebral disk dimensions after a loading task and the relationship with stature change measurements. To test the hypothesis that there would be a linear relationship between overall stature change determined by stadiometry and markers of lumbar disk height loss determined from magnetic resonance imaging (MRI). The short-term loading response of the lumbar spine was evaluated with both stadiometry and MRI, using a within-subject repeated-measures design. Measures were obtained both before and after 15 minutes of walking wearing a weighted vest (20% of body mass). Stature loss measured on the stadiometer was compared with change in lumbar spine length assessed from the MRI images. A university laboratory. Participants (N=13; mean age +/- SD, 28.5+/-5.2y; mean height +/- SD, 1.76+/-0.10m; mean body mass +/- SD, 76.6+/-14.9kg) were invited to take part in the investigation. The group was mixed (9 men, 4 women) and comprised people with no history of low back pain. Not applicable. Lumbar spine length assessed via MRI and stature change measured via stadiometry. A significant height loss was observed over the complete lumbar spine (Pstature loss (r=.61). The results were supportive of the use of stadiometry as an indirect measure of changes in intervertebral disk height.

  5. Stem cell therapy for intervertebral disc regeneration: review article

    Directory of Open Access Journals (Sweden)

    Mohsen Sheykhhasan

    2017-02-01

    Full Text Available Intervertebral disks (IVD acts as shock absorber between each of the vertebrae in the spinal column by keeping the vertebrae separated when the shock caused by the action. They also serve to protect the nerves that run down the middle of the spine and intervertebral disks. The disks are made of fibrocartilaginous material. The outside of the disk is made of a strong material called the annulus fibrosus. Inside this protective covering is a jelly-like substance known as mucoprotein gel. This interior is known as the nucleus pulposus. The nucleus pulposus consists of large vacuolated notochord cells, small chondrocyte-like cells, collagen fibrils, and aggrecan, a proteoglycan that aggregates by binding to hyaluronan. Attached to each aggrecan molecule are glycosaminoglycan (GAG chains of chondroitin sulfate and keratan sulfate. Intervertebral disks degeneration is frequently associated with low back and neck pain, which accounts as a disability. Despite the known outcomes of the Intervertebral disks degeneration cascade, the treatment of IVD degeneration is limited in that available conservative and surgical treatments do not reverse the pathology or restore the IVD tissue. Regenerative medicine for IVD degeneration, by injection of Intervertebral disks cells, chondrocytes or stem cells, has been extensively studied in the past decade in various animal models of induced IVD degeneration, and has progressed to clinical trials in the treatment of various spinal disease. Despite preliminary results showing positive effects of cell-injection strategies for IVD regeneration, detailed basic research on Intervertebral disks cells and their niche demonstrates that transplanted cells are unable to survive and adapt in the avascular niche of the IVD. For this therapeutic strategy to succeed, the indications for its use and the patients who would benefit need to be better defined. To surmount these obstacles, the solution will be identified only by focused

  6. MR imaging of spondylolytic spondylolisthesis: changes of intervertebral foramen and nerve root compression

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Hyung [Ajou Univ. College of Medicine, Seoul (Korea, Republic of); Chung, Tae Sub; Kim, Young Soo [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

    1999-08-01

    To evaluate the factors affecting intervertebral foramen stenosis and nerve root compression in spondylolytic spondylolisthesis. We investigated 120 intervertebral foramina of 60 patients with spondylolytic spondylolisthesis who had undergone lumbar MRI. A retrospective review of their MR images revealed the degree of intervertebral foramen stenosis and causes of nerve root compression. The relationship between disk height diminution following spondylolysis and degree of intervertebral foramen stenosis was also evaluated. Forty eight of 60 patients showed a similar degree of intervertebral foramen stenosis, and in 12 patients the degree of stenosis was different. In 110 intervertebral foramina, stenosis of both the superior and inferior compartments of intervertebral foramina was demonstrated. In 37 of 120 cases (30.8%), stenosis was mild ; in 44 of 120 (36.7%) it was modcrate, and in 29 of 120 (24.2%) it was severe. Stenosis of the inferior compartment was demonstrated in ten of 120 intervertebral foramina (8.3%). Nerve root compression was caused by posterior bulging of the intervertebral disk (65/120), descent of the pedicle (51/120), an isthmic bony segment above the site of spondylolytic (44/120), a bony spur formed at a spondylolytic site (11/120), and fibrocartilaginous callus at a spondylolytic site (5/48). In all cases there was degenerative change of the intervertebral disk at the affected level. There was no relationship between degree of disk height diminution and degree of intervertebral foramen stenosis (p > 0.05). The degree of intervertebral foramen stenosis and causes of nerve root compression in spondylolytic spondylolisthesis are variable, and MRI demonstrates them precisely. There was no positive relationship between degree of nerve root compression at an intervertebral foramen and degree of spondylolysis and degeneration of an intervertebral foramen. The degree of nerve root compression is believed to be another criterion for describing

  7. MR imaging of spondylolytic spondylolisthesis: changes of intervertebral foramen and nerve root compression

    International Nuclear Information System (INIS)

    Kim, Ji Hyung; Chung, Tae Sub; Kim, Young Soo

    1999-01-01

    To evaluate the factors affecting intervertebral foramen stenosis and nerve root compression in spondylolytic spondylolisthesis. We investigated 120 intervertebral foramina of 60 patients with spondylolytic spondylolisthesis who had undergone lumbar MRI. A retrospective review of their MR images revealed the degree of intervertebral foramen stenosis and causes of nerve root compression. The relationship between disk height diminution following spondylolysis and degree of intervertebral foramen stenosis was also evaluated. Forty eight of 60 patients showed a similar degree of intervertebral foramen stenosis, and in 12 patients the degree of stenosis was different. In 110 intervertebral foramina, stenosis of both the superior and inferior compartments of intervertebral foramina was demonstrated. In 37 of 120 cases (30.8%), stenosis was mild ; in 44 of 120 (36.7%) it was modcrate, and in 29 of 120 (24.2%) it was severe. Stenosis of the inferior compartment was demonstrated in ten of 120 intervertebral foramina (8.3%). Nerve root compression was caused by posterior bulging of the intervertebral disk (65/120), descent of the pedicle (51/120), an isthmic bony segment above the site of spondylolytic (44/120), a bony spur formed at a spondylolytic site (11/120), and fibrocartilaginous callus at a spondylolytic site (5/48). In all cases there was degenerative change of the intervertebral disk at the affected level. There was no relationship between degree of disk height diminution and degree of intervertebral foramen stenosis (p > 0.05). The degree of intervertebral foramen stenosis and causes of nerve root compression in spondylolytic spondylolisthesis are variable, and MRI demonstrates them precisely. There was no positive relationship between degree of nerve root compression at an intervertebral foramen and degree of spondylolysis and degeneration of an intervertebral foramen. The degree of nerve root compression is believed to be another criterion for describing

  8. Clinical characterization of thoracolumbar and lumbar intervertebral disk extrusions in English Cocker Spaniels.

    Science.gov (United States)

    Cardy, Thomas J A; Tzounos, Caitlin E; Volk, Holger A; De Decker, Steven

    2016-02-15

    To assess the anatomic distribution of thoracolumbar and lumbar intervertebral disk extrusions (IVDEs) in English Cocker Spaniels as compared with findings in Dachshunds and to characterize clinical findings in English Cocker Spaniels with thoracolumbar or lumbar IVDEs affecting various regions of the vertebral column. Retrospective observational study. 81 English Cocker Spaniels and 81 Dachshunds with IVDEs. Signalment, clinical signs, neurologic examination findings, and affected intervertebral disk spaces (IVDSs) were recorded for both breeds. Management methods and outcomes were recorded for English Cocker Spaniels. Lesions were categorized as thoracolumbar (IVDSs T9-10 through L1-2), midlumbar (L2-3 through L4-5), or caudal lumbar (L5-6 through L7-S1). Midlumbar and caudal lumbar IVDEs were significantly more common in English Cocker Spaniels than in Dachshunds. English Cocker Spaniels with caudal lumbar IVDEs had a longer median duration of clinical signs before evaluation and more commonly had unilateral pelvic limb lameness or spinal hyperesthesia as the predominant clinical sign than did those with IVDEs at other sites. Those with caudal lumbar IVDEs less commonly had neurologic deficits and had a higher median neurologic grade (indicating lesser severity), shorter mean postoperative hospitalization time, and faster mean time to ambulation after surgery than those with other sites affected. These variables did not differ between English Cocker Spaniels with thoracolumbar and midlumbar IVDEs. Caudal and midlumbar IVDEs were more common in English Cocker Spaniels than in Dachshunds. English Cocker Spaniels with caudal lumbar IVDE had clinical signs and posttreatment responses that differed from those in dogs with midlumbar or thoracolumbar IVDE.

  9. Synthesis and characterization of injectable composites of poly[D,L-lactide-co-(ε-caprolactone)] reinforced with β-TCP and CaCO3 for intervertebral disk augmentation.

    Science.gov (United States)

    López, Alejandro; Persson, Cecilia; Hilborn, Jöns; Engqvist, Håkan

    2010-10-01

    Degeneration of the intervertebral disk constitutes one of the major causes of low back pain in adults aged 20-50 years old. In this study, injectable, in situ setting, degradable composites aimed for intervertebral disk replacement were prepared. β-TCP and calcium carbonate particles were mixed into acrylic-terminated oligo[D,L-lactide-co-(ε-caprolactone)], which were crosslinked at room temperature. The structure of the oligomers was confirmed by 1H-NMR spectroscopy. The composites were examined via SEM, and the mechanical properties of the crosslinked networks were determined. The porous β-TCP particles showed good mechanical anchorage to the matrix due to polymer penetration into the pores. In vitro degradation tests showed that the composites containing β-TCP slowly degraded, whereas the composites containing CaCO3 exhibited apatite formation capacity. It was concluded that the surface area, morphology, and solubility of the fillers might be used to control the degradation properties. The incorporation of fillers also increased both the elastic modulus and the maximum compression strength of the composites, properties that were similar to those of the physiological disk. These materials have potential for long-term intervertebral disk replacement and regenerative scaffolds because of their low degradation rates, bioactivity, and mechanical properties.

  10. Doença do disco intervertebral em trabalhadores da perfuração de petróleo Intervertebral disk disease among oil drilling workers

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Pereira Fernandes

    2000-09-01

    Full Text Available Estudo transversal em 1.026 trabalhadores em distrito de perfuração de petróleo do Nordeste brasileiro mostrou prevalência global de doença do disco intervertebral lombar de 5%, variando de 1,8% (atividades sem manuseio de carga, 4,5% (manuseio ocasional até 7,2% (manuseio habitual. Tal prevalência foi de 11,4% em operadores de sonda de perfuração de petróleo com mais de 40 anos de idade e de 10,5% naqueles com mais de 15 anos de empresa. A razão de prevalência (R.P. à associação entre trabalho em operação de sonda e doença do disco foi 2,3 (I.C. 95%: 1,3, 4,0. Para minimizar o efeito sobrevivência do trabalhador sadio foram usadas informações retrospectivas acerca da exposição. A informação referente à ocupação atual em lugar do histórico ocupacional resultaria em RP subestimada de 1,1 (I.C. 95%: 0,6, 1,9. A regressão logística ratificou os achados da análise tabular. Não houve confundimento nem interação. O incremento da indústria de petróleo no país e as alterações na gestão e contratação da força de trabalho implicam mudanças no gerenciamento de risco e controle de saúde, além de pronta intervenção ergonômica para controle da doença.A cross-sectional study among 1,026 oil drilling workers in Northeast Brazil found a prevalence rate of 5% for intervertebral disk disease, varying from 1.8% (activities without heavy lifting and 4.5% (occasional lifting to 7.2% (routine lifting. Disease prevalence was 10.5% among drilling workers with more than 15 years in the industry and 11.3% among those over 40 years of age. Prevalence ratio (PR for the association between working in oil drilling operations and intervertebral disk disease was 2.3 (95% CI: 1.3-4.0. Retrospective information about exposure was collected to minimize the healthy worker survival effect. Using information on current occupation instead of occupational life history would cause an underestimated PR of 1.1 (95% CI: 0.6-1.9. Logistic

  11. Anisotropic Multishell Analytical Modeling of an Intervertebral Disk Subjected to Axial Compression.

    Science.gov (United States)

    Demers, Sébastien; Nadeau, Sylvie; Bouzid, Abdel-Hakim

    2016-04-01

    Studies on intervertebral disk (IVD) response to various loads and postures are essential to understand disk's mechanical functions and to suggest preventive and corrective actions in the workplace. The experimental and finite-element (FE) approaches are well-suited for these studies, but validating their findings is difficult, partly due to the lack of alternative methods. Analytical modeling could allow methodological triangulation and help validation of FE models. This paper presents an analytical method based on thin-shell, beam-on-elastic-foundation and composite materials theories to evaluate the stresses in the anulus fibrosus (AF) of an axisymmetric disk composed of multiple thin lamellae. Large deformations of the soft tissues are accounted for using an iterative method and the anisotropic material properties are derived from a published biaxial experiment. The results are compared to those obtained by FE modeling. The results demonstrate the capability of the analytical model to evaluate the stresses at any location of the simplified AF. It also demonstrates that anisotropy reduces stresses in the lamellae. This novel model is a preliminary step in developing valuable analytical models of IVDs, and represents a distinctive groundwork that is able to sustain future refinements. This paper suggests important features that may be included to improve model realism.

  12. A cross-sectional study: serum CCL3/MIP-1α levels may reflect lumbar intervertebral disk degeneration in Han Chinese people

    Directory of Open Access Journals (Sweden)

    Zhang YL

    2018-03-01

    Full Text Available Yi-Li Zhang,1,2,* Bei Li,1,2,* Zeng-Huan Zhou1 1School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, People’s Republic of China; 2School of Health Services Management, Southern Medical University, Guangzhou, Guangdong Province, People’s Republic of China *These authors contributed equally to this work Background: The macrophage inflammatory protein-1α (MIP-1α, also named chemokine cytokine ligand 3 (CCL3, has been detected in nucleus pulposus and increased following cytokine stimulation. Objective: The current study was performed to explore the relationship between serum CCL3/MIP-1α levels with lumbar intervertebral disk degeneration (IDD. Patients and methods: A total of 132 disk degeneration patients confirmed by magnetic resonance imaging and 126 healthy controls were enrolled in the current study. Radiological evaluation of the IDD was conducted using a 3.0-T magnetic resonance imaging scanner for entire lumbar vertebra region. Degeneration of intervertebral disk was assessed by Schneiderman criteria. Serum CCL3/MIP-1α levels were investigated using a sandwich enzyme-linked immunosorbent assay. The Visual Analog Scale scores and Oswestry Disability Index index were recorded for clinical severity. Results: Elevated concentrations of CCL3 in serum were found in IDD patients compared with asymptomatic volunteers. The case group included 49 IDD patients with grade 1, 42 with grade 2, and 41 with grade 3. Grade 3 and 2 had significantly higher CCL3 concentrations in serum compared with those with grade 1. The serum CCL3 levels were positively related to the degree of disk degeneration. In addition, the serum CCL3 levels also demonstrated a significant correlation with the clinical severity determined by Visual Analog Scale scores and Oswestry Disability Index index. Conclusion: Serum CCL3 may serve as a biomarker of IDD. Keywords: chemokine cytokine ligand 3, intervertebral disk degeneration, cross

  13. CT recognition of lateral lumbar disk herniation

    International Nuclear Information System (INIS)

    Williams, A.L.; Haughton, V.M.; Daniels, D.L.; Thornton, R.S.

    1982-01-01

    Although computed tomography (CT) has been shown to be useful in diagnosing posterolateral and central lumbar disk herniations, its effectiveness in demonstrating lateral herniated disks has not been emphasized. The myelographic recognition of those herniations may be difficult because root sheaths or dural sacs may not be deformed. A total of 274 CT scans interpreted as showing lumbar disk herniation was reviewed. Fourteen (5%) showed a lateral disk herniation. The CT features of a lateral herniated disk included: (1) focal protrusion of the disk margin within or lateral to the intervertebral foramen: (2) displacement of epidural fat within the intervertebral foramen; (3) absence of dural sac deformity; and (4) soft-tissue mass within or lateral to the intervertebral foramen. Because it can image the disk margin and free disk fragments irrespective of dural sac or root sheath deformity, CT may be more effective than myelography for demonstrating the presence and extent of lateral disk herniation

  14. Herniated lumbar intervertebral disk

    International Nuclear Information System (INIS)

    Hochhauser, L.; Cacayorin, E.D.; Karcnik, T.J.; McGowan, D.P.; Clark, K.G.; Storrs, D.; Kieffer, S.A.

    1988-01-01

    From a series of 25 patients with low-back pain and sciatica who subsequently underwent surgical exploration, 24 lumbar herniated disks and one asymmetrically bulging disk were correctly diagnosed with use of a 0.5-T MR imaging unit. The radiologic findings on saggital images included a polypoid protrusion beyond the posterior margin of the vertebral bodies more clearly displayed with T1-weighted than with T-2 weighted sequences and a focal extension into the extradural space on axial views. In most, the signal intensity of HNP was isointense to the disk of origin. The study suggests that MR imaging is currently capable of accurately predicting an HNP. The diagnosis is based primarily on morphologic characteristics rather than signal intensity alterations

  15. Cytokine Involvement in Biological Inflammation Related to Degenerative Disorders of the Intervertebral Disk: A Narrative Review.

    Science.gov (United States)

    De Geer, Christopher M

    2018-03-01

    The purpose of this narrative literature review is to discuss the literature regarding the potential role that cytokines play in degenerative disk disease. The inclusion criteria were studies that used inflammatory mediators in advancing disk disease processes. Research studies were limited to the last 3 decades that had free full-text available online in English. Exclusion criteria were review articles and articles pertaining to temporomandibular joints and other joints of the body other than the intervertebral disk. The following databases were searched: PubMed, EBSCOhost, and Google Scholar through March 13, 2017. A total of 82 studies were included in this review. The papers were reviewed for complex mechanisms behind the degenerative cascade, emphasizing the role of proinflammatory cytokines, which may be instrumental in processes of inflammation, neurologic pain, and disk degeneration. Interleukin-1β and tumor necrosis factor α were among the more notable cytokines involved in this cascade. Because monocyte chemoattractant protein-1 stimulates and activates macrophages in the event of infiltration, additional proinflammatory cytokines are released to act on molecules to promote blood and nerve ingrowth, resulting in pain signaling and tissue degradation. Excessive inflammation and/or tissue damage initiates a pathologic imbalance between anabolic and catabolic processes. This literature review describes how inflammatory and biochemical changes may trigger disk degeneration. Proinflammatory cytokines stimulate microvascular blood and nerve ingrowth, resulting in pain signaling and tissue degradation. This may sensitize a person to chemical and/or mechanical stimuli, contributing to severe low back pain.

  16. Intervertebral Disc Degeneration : The Role of the Mitochondrial Pathway in Annulus Fibrosus Cell Apoptosis Induced by Overload

    OpenAIRE

    Rannou, François; Lee, Tzong-Shyuan; Zhou, Rui-Hai; Chin, Jennie; Lotz, Jeffrey C.; Mayoux-Benhamou, Marie-Anne; Barbet, Jacques Patrick; Chevrot, Alain; Shyy, John Y.-J.

    2004-01-01

    Degeneration of the intervertebral disk (IVD) is a major pathological process implicated in low back pain and is a prerequisite to disk herniation. Although mechanical stress is an important modulator of the degeneration, the underlying molecular mechanism remains unclear. The association of human IVD degeneration, assessed by magnetic resonance imaging, with annulus fibrosus cell apoptosis and anti-cytochrome c staining revealed that the activation of the mitochondria-dependent apoptosome wa...

  17. Gradient-echo imaging of intervertebral disk degeneration and facet joint disease

    International Nuclear Information System (INIS)

    Berns, D.H.; Kormos, D.; Modic, M.T.; Carter, J.; Masaryk, T.J.; Ross, J.S.

    1988-01-01

    The purpose of this study was to evaluate the accuracy of gradient-echo, partial-flip angle images in the evaluation of components of degenerative spine disease. First, cadaveric spines were studied with plain radiographs, high-resolution CT, T1-weighted spin-echo (SE) MR images (repetition time msec/echo time msec=500/17). T2-weighted SE images (2,000/30-90), and fast low-angle shot (FLASH) images (200/10.50 0 ) before and after intradiskal injection of air (0.1-1cc). Second, lumbar spine MR images were retrospectively evaluated to compare gradient-echo and SE sequences. Results indicate that the signal intensity changes of the intervertebral disk related to degeneration were best appreciated on T2-weighted SE studies in both groups. Vacuum phenomenon and calcification were most accurately assessed with FLASH imaging (based on susceptibility changes) and CT images. SE images appeared more sensitive to adjacent marrow change. In the facet joints, CT was more accurate for changes in the subarticular bone, but FLASH images were more sensitive to change in the articular cartilage

  18. Annulus Fibrosus Can Strip Hyaline Cartilage End Plate from Subchondral Bone: A Study of the Intervertebral Disk in Tension.

    Science.gov (United States)

    Balkovec, Christian; Adams, Michael A; Dolan, Patricia; McGill, Stuart M

    2015-10-01

    Study Design Biomechanical study on cadaveric spines. Objective Spinal bending causes the annulus to pull vertically (axially) on the end plate, but failure mechanisms in response to this type of loading are poorly understood. Therefore, the objective of this study was to identify the weak point of the intervertebral disk in tension. Methods Cadaveric motion segments (aged 79 to 88 years) were dissected to create midsagittal blocks of tissue, with ∼10 mm of bone superior and inferior to the disk. From these blocks, 14 bone-disk-bone slices (average 4.8 mm thick) were cut in the frontal plane. Each slice was gripped by its bony ends and stretched to failure at 1 mm/s. Mode of failure was recorded using a digital camera. Results Of the 14 slices, 10 failed by the hyaline cartilage being peeled off the subchondral bone, with the failure starting opposite the lateral annulus and proceeding medially. Two slices failed by rupturing of the trabecular bone, and a further two failed in the annulus. Conclusions The hyaline cartilage-bone junction is the disk's weak link in tension. These findings provide a plausible mechanism for the appearance of bone and cartilage fragments in herniated material. Stripping cartilage from the bony end plate would result in the herniated mass containing relatively stiff cartilage that does not easily resorb.

  19. Knockdown of asporin affects transforming growth factor-β1-induced matrix synthesis in human intervertebral annulus cells

    Directory of Open Access Journals (Sweden)

    Xu Jiang

    2016-10-01

    Conclusion: Our results have verified a functional feedback loop between TGF-β1 and asporin in human intervertebral annulus cells indicating that TGF-β1-induced annulus matrix biosynthesis can be significantly upregulated by knockdown of asporin. Therefore, asporin could be a potential new therapeutic target and inhibition of asporin could be adopted to enhance the anabolic effect of TGF-β1 in human intervertebral annulus cells in degenerative IVD diseases.

  20. Fabrication of a biomimetic elastic intervertebral disk scaffold using additive manufacturing

    International Nuclear Information System (INIS)

    Whatley, Benjamin R; Kuo, Jonathan; Shuai, Cijun; Wen Xuejun; Damon, Brooke J

    2011-01-01

    A custom-designed three-dimensional additive manufacturing device was developed to fabricate scaffolds for intervertebral disk (IVD) regeneration. This technique integrated a computer with a device capable of 3D movement allowing for precise motion and control over the polymer scaffold resolution. IVD scaffold structures were designed using computer-aided design to resemble the natural IVD structure. Degradable polyurethane (PU) was used as an elastic scaffold construct to mimic the elastic nature of the native IVD tissue and was deposited at a controlled rate using ultra-fine micropipettes connected to a syringe pump. The elastic PU was extruded directly onto a collecting substrate placed on a freezing stage. The three-dimensional movement of the computer-controlled device combined with the freezing stage enabled precise control of polymer deposition using extrusion. The addition of the freezing stage increased the polymer solution viscosity and hardened the polymer solution as it was extruded out of the micropipette tip. This technique created scaffolds with excellent control over macro- and micro-structure to influence cell behavior, specifically for cell adhesion, proliferation, and alignment. Concentric lamellae were printed at a high resolution to mimic the native shape and structure of the IVD. Seeded cells aligned along the concentric lamellae and acquired cell morphology similar to native tissue in the outer portion of the IVD. The fabricated scaffolds exhibited elastic behavior during compressive and shear testing, proving that the scaffolds could support loads with proper fatigue resistance without permanent deformation. Additionally, the mechanical properties of the scaffolds were comparable to those of native IVD tissue.

  1. Fabrication of a biomimetic elastic intervertebral disk scaffold using additive manufacturing.

    Science.gov (United States)

    Whatley, Benjamin R; Kuo, Jonathan; Shuai, Cijun; Damon, Brooke J; Wen, Xuejun

    2011-03-01

    A custom-designed three-dimensional additive manufacturing device was developed to fabricate scaffolds for intervertebral disk (IVD) regeneration. This technique integrated a computer with a device capable of 3D movement allowing for precise motion and control over the polymer scaffold resolution. IVD scaffold structures were designed using computer-aided design to resemble the natural IVD structure. Degradable polyurethane (PU) was used as an elastic scaffold construct to mimic the elastic nature of the native IVD tissue and was deposited at a controlled rate using ultra-fine micropipettes connected to a syringe pump. The elastic PU was extruded directly onto a collecting substrate placed on a freezing stage. The three-dimensional movement of the computer-controlled device combined with the freezing stage enabled precise control of polymer deposition using extrusion. The addition of the freezing stage increased the polymer solution viscosity and hardened the polymer solution as it was extruded out of the micropipette tip. This technique created scaffolds with excellent control over macro- and micro-structure to influence cell behavior, specifically for cell adhesion, proliferation, and alignment. Concentric lamellae were printed at a high resolution to mimic the native shape and structure of the IVD. Seeded cells aligned along the concentric lamellae and acquired cell morphology similar to native tissue in the outer portion of the IVD. The fabricated scaffolds exhibited elastic behavior during compressive and shear testing, proving that the scaffolds could support loads with proper fatigue resistance without permanent deformation. Additionally, the mechanical properties of the scaffolds were comparable to those of native IVD tissue.

  2. The viscoelastic standard nonlinear solid model: predicting the response of the lumbar intervertebral disk to low-frequency vibrations.

    Science.gov (United States)

    Groth, Kevin M; Granata, Kevin P

    2008-06-01

    Due to the mathematical complexity of current musculoskeletal spine models, there is a need for computationally efficient models of the intervertebral disk (IVD). The aim of this study is to develop a mathematical model that will adequately describe the motion of the IVD under axial cyclic loading as well as maintain computational efficiency for use in future musculoskeletal spine models. Several studies have successfully modeled the creep characteristics of the IVD using the three-parameter viscoelastic standard linear solid (SLS) model. However, when the SLS model is subjected to cyclic loading, it underestimates the load relaxation, the cyclic modulus, and the hysteresis of the human lumbar IVD. A viscoelastic standard nonlinear solid (SNS) model was used to predict the response of the human lumbar IVD subjected to low-frequency vibration. Nonlinear behavior of the SNS model was simulated by a strain-dependent elastic modulus on the SLS model. Parameters of the SNS model were estimated from experimental load deformation and stress-relaxation curves obtained from the literature. The SNS model was able to predict the cyclic modulus of the IVD at frequencies of 0.01 Hz, 0.1 Hz, and 1 Hz. Furthermore, the SNS model was able to quantitatively predict the load relaxation at a frequency of 0.01 Hz. However, model performance was unsatisfactory when predicting load relaxation and hysteresis at higher frequencies (0.1 Hz and 1 Hz). The SLS model of the lumbar IVD may require strain-dependent elastic and viscous behavior to represent the dynamic response to compressive strain.

  3. Long-Term Creep Behavior of the Intervertebral Disk: Comparison between Bioreactor Data and Numerical Results

    Energy Technology Data Exchange (ETDEWEB)

    Castro, A. P. G., E-mail: apgcastro@dem.uminho.pt [Center for Mechanical and Materials Technologies, Department of Mechanical Engineering, University of Minho, Guimarães (Portugal); INSIGNEO Institute for in silico Medicine, Department of Mechanical Engineering, University of Sheffield, Sheffield (United Kingdom); Paul, C. P. L. [Department of Orthopaedic Surgery, VU Medical Center, Amsterdam (Netherlands); Research Institute MOVE, Faculty of Human Movement Sciences, VU Medical Center, Amsterdam (Netherlands); Detiger, S. E. L.; Smit, T. H.; Royen, B. J. van [Department of Orthopaedic Surgery, VU Medical Center, Amsterdam (Netherlands); Research Institute MOVE, Faculty of Human Movement Sciences, VU Medical Center, Amsterdam (Netherlands); Skeletal Tissue Engineering Group Amsterdam, VU Medical Center, Amsterdam (Netherlands); Pimenta Claro, J. C. [Center for Mechanical and Materials Technologies, Department of Mechanical Engineering, University of Minho, Guimarães (Portugal); Mullender, M. G. [Department of Orthopaedic Surgery, VU Medical Center, Amsterdam (Netherlands); Research Institute MOVE, Faculty of Human Movement Sciences, VU Medical Center, Amsterdam (Netherlands); Department of Plastic, Reconstructive and Hand Surgery, VU Medical Center, Amsterdam (Netherlands); Alves, J. L. [Center for Mechanical and Materials Technologies, Department of Mechanical Engineering, University of Minho, Guimarães (Portugal)

    2014-11-20

    The loaded disk culture system is an intervertebral disk (IVD)-oriented bioreactor developed by the VU Medical Center (VUmc, Amsterdam, The Netherlands), which has the capacity of maintaining up to 12 IVDs in culture, for approximately 3 weeks after extraction. Using this system, eight goat IVDs were provided with the essential nutrients and submitted to compression tests without losing their biomechanical and physiological properties, for 22 days. Based on previous reports (Paul et al., 2012, 2013; Detiger et al., 2013), four of these IVDs were kept in physiological condition (control) and the other four were previously injected with chondroitinase ABC (CABC), in order to promote degenerative disk disease (DDD). The loading profile intercalated 16 h of activity loading with 8 h of loading recovery to express the standard circadian variations. The displacement behavior of these eight IVDs along the first 2 days of the experiment was numerically reproduced, using an IVD osmo-poro-hyper-viscoelastic and fiber-reinforced finite element (FE) model. The simulations were run on a custom FE solver (Castro et al., 2014). The analysis of the experimental results allowed concluding that the effect of the CABC injection was only significant in two of the four IVDs. The four control IVDs showed no signs of degeneration, as expected. In what concerns to the numerical simulations, the IVD FE model was able to reproduce the generic behavior of the two groups of goat IVDs (control and injected). However, some discrepancies were still noticed on the comparison between the injected IVDs and the numerical simulations, namely on the recovery periods. This may be justified by the complexity of the pathways for DDD, associated with the multiplicity of physiological responses to each direct or indirect stimulus. Nevertheless, one could conclude that ligaments, muscles, and IVD covering membranes could be added to the FE model, in order to improve its accuracy and properly describe the

  4. Correlations between radiographic, magnetic resonance and histological examinations on the degeneration of human lumbar intervertebral discs

    Directory of Open Access Journals (Sweden)

    Delio Eulalio Martins

    Full Text Available CONTEXT AND OBJECTIVE: There is controversy regarding which imaging method is best for identifying early degenerative alterations in intervertebral discs. No correlations between such methods and histological finds are presented in the literature. The aim of this study was to correlate the thickness of intervertebral discs measured on simple radiographs with the degree of degeneration seen on magnetic resonance images and the histological findings relating to nerve ends inside the discs. DESIGN AND SETTING: Cross-sectional correlation study on the lumbar spines of human cadavers, at Universidade Federal de São Paulo (Unifesp, São Paulo, Brazil. METHODS: Ten lumbar spinal columns were extracted from human cadavers and subjected to magnetic resonance imaging and simple radiography. They were classified according to the degree of disc degeneration seen on magnetic resonance, and the thickness of the discs was measured on radiographs. The intervertebral discs were then extracted, embedded in paraffin and analyzed immunohistochemically with protein S100, and the nerve fibers were counted and classified. RESULTS: No correlation was observed between the thickness of the intervertebral discs and the degree of degeneration seen on magnetic resonance images. Only the uppermost lumbar discs (L1/L2 and L2/L3 presented a correlation between their thickness and type I and IV nerve endings. CONCLUSION: Reduced disc thickness is unrelated to increased presence of nerve ends in intervertebral discs, or to the degree of disc degeneration.

  5. [Research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration].

    Science.gov (United States)

    Liang, Hang; Deng, Xiangyu; Shao, Zengwu

    2017-10-01

    To summarize the research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration and deduce the therapeutic potential of endogenous repair for intervertebral disc degeneration. The original articles about intervertebral disc endogenous stem cells for intervertebral disc regeneration were extensively reviewed; the reparative potential in vivo and the extraction and identification in vitro of intervertebral disc endogenous stem cells were analyzed; the prospect of endogenous stem cells for intervertebral disc regeneration was predicted. Stem cell niche present in the intervertebral discs, from which stem cells migrate to injured tissues and contribute to tissues regeneration under certain specific microenvironment. Moreover, the migration of stem cells is regulated by chemokines system. Tissue specific progenitor cells have been identified and successfully extracted and isolated. The findings provide the basis for biological therapy of intervertebral disc endogenous stem cells. Intervertebral disc endogenous stem cells play a crucial role in intervertebral disc regeneration. Therapeutic strategy of intervertebral disc endogenous stem cells is proven to be a promising biological approach for intervertebral disc regeneration.

  6. Ozone therapy for t he complex prolapse of lumbar intervertebral disc: a clinical observation

    International Nuclear Information System (INIS)

    Peng Yong; Wei Mengqi; Wu Juan; Zhou Jianshou; Yang Yong; Zhao Hongliang; Shi Mingguo

    2010-01-01

    Objective: To evaluate the therapeutic outcome of ozone injection therapy for the treatment of complex prolapse of lumbar intervertebral disc, which is accompanied with spinal stenosis due to hypertrophy of ligamentum flavum, degeneration of intervertebral facet joints, intervertebral hyperosteogeny and degeneration, lumbar muscle strain and negative pressure in intervertebral discs. Methods: Seventy patients with simple intervertebral disc prolapse (simple group) and 70 patients with complex intervertebral disc prolapse (complex group) were selected for the study. The complex intervertebral disc prolapse included negative pressure in intervertebral disc (n=11), recurrence after resection of nucleus polposus of intervertebral disc (n=5), spinal stenosis (n=10), degeneration of intervertebral facet joints and interver-tebral hyperosteogeny (n=30), stenosis of lateral recess (n=4) and lumbar muscle strain (n=10). All patients were treated with ozone injection under the CT guidance. A total of 2-3 ml ozone with the concentration of 40-50 μg / ml was injected into the intervertebral disk and a total of 5-8 ml ozone with the concentration of 30-40 μg / ml was injected into the paraspinal space. Infiltration injection into the pain spots with 20 ml ozone was carried out in patients with lumbar muscle strain. Results: A comparison of the therapeutic outcomes between simple group and complex group was made. Immediate relief from clinical symptoms was obtained in 80% of all treated patients. The effective rate one week after the procedure was 95%, which became 96% at 3-6 months after the treatment. Conclusion: Correct clinical diagnosis, skilled and accurate manipulation during the surgery and reasonable use of ozone injection in the treatment of soft tissue injury, etc. can markedly improve the therapeutic effect for complex lumbar intervertebral disc prolase. (authors)

  7. Human Amniotic Tissue-derived Allograft, NuCel, in Posteriolateral Lumbar Fusions for Degenerative Disc Disease

    Science.gov (United States)

    2017-09-14

    Lumbar Degenerative Disc Disease; Spinal Stenosis; Spondylolisthesis; Spondylosis; Intervertebral Disk Displacement; Intervertebral Disk Degeneration; Spinal Diseases; Bone Diseases; Musculoskeletal Diseases; Spondylolysis

  8. CT-guided percutaneous laser disk decompression for cervical and lumbar disk hernia

    International Nuclear Information System (INIS)

    Shimizu, Kanichiro; Koyama, Tutomu; Harada, Junta; Abe, Toshiaki

    2008-01-01

    Percutaneous laser disk decompression under X-ray fluoroscopy was first reported in 1987 for minimally invasive therapy of lumbar disk hernia. In patients with disk hernia, laser vaporizes a small portion of the intervertebral disk thereby reducing the volume and pressure of the affected disk. We present the efficacy and safety of this procedure, and analysis of fair or poor response cases. In our study, 226 cases of lumbar disk hernia and 7 cases of cervical disk hernia were treated under CT guided PLDD. Japan Orthopedic Association (JOA) score and Mac-Nab criteria were investigated to evaluate the response to treatment. Improvement ratio based on the JOA score was calculated as follows. Overall success rate was 91.6% in cases lumber disk hernia, and 100% in cases of cervical disk hernia. We experienced two cases with two cases with postoperative complication. Both cases were treated conservatively. The majority of acute cases and post operative cases were reported to be 'good' on Mac-Nab criteria. Cases of fair or poor response on Mac-Nab criteria were lateral type, foraminal stenosis or large disk hernia. CT-guided PLDD is a safe and accurate procedure. The overall success rate can be increased by carefully selecting patients. (author)

  9. Ho:YAG laser: intervertebral disk cell interaction using three-dimensional cell culture system

    Science.gov (United States)

    Sato, Masato; Ishihara, Miya; Arai, Tsunenori; Asazuma, Takashi; Kikuchi, Toshiyuki; Kikuchi, Makoto; Fujikawa, Kyosuke

    2000-06-01

    The purpose of this study is to evaluate the influence on the intervertebral disc cells after laser irradiation using three- dimensional culture system and to clarify the optimum Ho:YAG laser irradiation condition on percutaneous laser disc decompression (PLDD) for lumbar disc herniation. Since the Ho:YAG laser ablation is characterized by water-vapor bubble dynamics, not only thermal effect but also acoustic effect on cell metabolism might occur in the intervertebral disc. We studied the disc cell reaction from the metabolic point of view to investigate photothermal and photoacoustic effects on three-dimensional cultured disc cell. Intervertebral discs were obtained from female 30 Japanese white rabbits weighing about 1 kg. A pulsed Ho:YAG laser (wavelength: 2.1 micrometer, pulse width: about 200 microseconds) was delivered through a 200 micrometer-core diameter single silica glass fiber. We used the Ho:YAG laser irradiation fluence ranging from 60 to approximately 800 J/cm2 at the fiber end. To investigate acoustic effect, the acoustic transducer constructed with polyvinylidene fluoride (PVdF) film and acoustic absorber was used to detect the stress wave. Thermocouple and thermography were used to investigate thermal effect. Concerning damage of plasma membrane and ability of matrix synthesis, thermal effect might mainly affect cell reaction in total energy of 54 J (closed to practically used condition), but in 27 J, acoustic effect might contribute to it. We found that total energy was key parameter among the optimum condition, so that temperature and/or stress wave may influence Ho:YAG laser-disc cell interactions.

  10. Aggrecan turnover in human intervertebral disc as determined by the racemization of aspartic acid

    NARCIS (Netherlands)

    Sivan, S.S.; Tsitron, E.; Wachtel, E.; Roughley, P.J.; Sakkee, N.; Ham, F. van der; Groot, J.de; Roberts, S.; Maroudas, A.

    2006-01-01

    We have used the racemization of aspartic acid as a marker for the "molecular age" of aggrecan components of the human intervertebral disc matrix (aggregating and non-aggregating proteoglycans as well as the different buoyant density fractions of aggrecan). By measuring the D/L Asp ratio of the

  11. Longevity of elastin in human intervertebral disc as probed by the racemization of aspartic acid

    DEFF Research Database (Denmark)

    Sivan, Sarit-Sara; Van El, Benno; Merkher, Yulia

    2012-01-01

    BACKGROUND: Aging and degeneration of human intervertebral disc (IVD) are associated with biochemical changes, including racemization and glycation. These changes can only be counteracted by protein turnover. Little is known about the longevity of IVD elastin in health or disease. Yet, such knowl...

  12. [Disk calcifications in children].

    Science.gov (United States)

    Schmit, P; Fauré, C; Denarnaud, L

    1985-05-01

    It is not unusual for intervertebral disk calcifications to be detected in pediatric practice, the 150 or so cases reported in the literature probably representing only a small proportion of lesions actually diagnosed. Case reports of 33 children with intervertebral disk calcifications were analyzed. In the majority of these patients (31 of 33) a diagnosis of "idiopathic" calcifications had been made, the cervical localization of the lesions being related to repeated ORL infections and/or trauma. A pre-existing pathologic factor was found in two cases (one child with juvenile rheumatoid arthritis treated by corticoids and one child with Williams and Van Beuren's syndrome). An uncomplicated course was noted in 31 cases, the symptomatology (pain, spinal stiffness and febricula) improving after several days. Complications developed in two cases: one child had very disabling dysphagia due to an anteriorly protruding cervical herniated disc and surgery was necessary; the other child developed cervicobrachial neuralgia due to herniated disc protrusion into the cervical spinal canal, but symptoms regressed within several days although calcifications persisted unaltered. These findings and the course of the rare complications documented in the literature suggest the need for the most conservative treatment possible in cases of disc calcifications in children.

  13. Geometry of the Intervertebral Volume and Vertebral Endplates of the Human Spine

    NARCIS (Netherlands)

    van der Houwen, E. B.; Baron, P.; Veldhuizen, A. G.; Burgerhof, J. G. M.; van Ooijen, P. M. A.; Verkerke, G. J.

    Replacement of a degenerated vertebral disc with an artificial intervertebral disc (AID) is currently possible, but poses problems, mainly in the force distribution through the vertebral column. Data on the intervertebral disc space geometry will provide a better fit of the prosthesis to the

  14. Geometry of the Intervertebral Volume and Vertebral Endplates of the Human Spine

    NARCIS (Netherlands)

    van der Houwen, E.B.; Baron, P.; Veldhuizen, A.G.; Burgerhof, J.G.M.; van Ooijen, P.M.A.; Verkerke, Gijsbertus Jacob

    2010-01-01

    Replacement of a degenerated vertebral disc with an artificial intervertebral disc (AID) is currently possible, but poses problems, mainly in the force distribution through the vertebral column. Data on the intervertebral disc space geometry will provide a better fit of the prosthesis to the

  15. Hyperosmotically induced volume change and calcium signaling in intervertebral disk cells: the role of the actin cytoskeleton.

    Science.gov (United States)

    Pritchard, Scott; Erickson, Geoffrey R; Guilak, Farshid

    2002-11-01

    Loading of the spine alters the osmotic environment in the intervertebral disk (IVD) as interstitial water is expressed from the tissue. Cells from the three zones of the IVD, the anulus fibrosus (AF), transition zone (TZ), and nucleus pulposus (NP), respond to osmotic stress with altered biosynthesis through a pathway that may involve calcium (Ca(2+)) as a second messenger. We examined the hypothesis that IVD cells respond to hyperosmotic stress by increasing the concentration of intracellular calcium ([Ca(2+)](i)) through a mechanism involving F-actin. In response to hyperosmotic stress, control cells from all zones decreased in volume and cells from the AF and TZ exhibited [Ca(2+)](i) transients, while cells from the NP did not. Extracellular Ca(2+) was necessary to initiate [Ca(2+)](i) transients. Stabilization of F-actin with phalloidin prevented the Ca(2+) response in AF and TZ cells and decreased the rate of volume change in cells from all zones, coupled with an increase in the elastic moduli and apparent viscosity. Conversely, actin breakdown with cytochalasin D facilitated Ca(2+) signaling while decreasing the elastic moduli and apparent viscosity for NP cells. These results suggest that hyperosmotic stress induces volume change in IVD cells and may initiate [Ca(2+)](i) transients through an actin-dependent mechanism.

  16. Intervertebral disc degeneration in dogs

    NARCIS (Netherlands)

    Bergknut, N.

    2011-01-01

    Back pain is common in both dogs and humans, and is often associated with intervertebral disc (IVD) degeneration. The IVDs are essential structures of the spine and degeneration can ultimately result in diseases such as IVD herniation or spinal instability. In order to design new treatments halting

  17. Intervertebral disc degeneration in dogs

    NARCIS (Netherlands)

    Bergknut, Niklas

    Back pain is common in both dogs and humans, and is often associated with intervertebral disc (IVD) degeneration. The IVDs are essential structures of the spine and degeneration can ultimately result in diseases such as IVD herniation or spinal instability. In order to design new treatments halting

  18. Hydrotherapy performance in elderly patients with herniated disk: a literature review

    Directory of Open Access Journals (Sweden)

    Suzileide Oliveira Costa

    2018-01-01

    Full Text Available Disk herniation (DH is a protrusion of the nucleus pulposus through the fibrous ring, arising because of trauma to the spine, which over time will damage the intervertebral discs. The objective of this work is to analyze the hydrotherapy effects on DH. It was done a descriptive analysis, with a bibliographic review on lumbar disc herniation, as well as its prevention measures, and developed and based on the analysis of scientific articles. Eleven articles were founded using the key-words disk herniation, physiotherapy and hydrotherapy on PubMed site. One of all obey to the inclusion propositions. In this way it concludes that the conservative treatment for lumbar disc herniation most indicated would be the hydrotherapy, because the physical properties of the water diminish the impact on the intervertebral discs due to the fluctuation causing a pain relief, thus providing a better quality of life to the patient.

  19. Ultrasound diagnosis of cervical spine intervertebral disks hernia

    International Nuclear Information System (INIS)

    Abdullajev, R.Ya.; Gapchenko, V.V.; Ponomarenko, S.O.

    2006-01-01

    Forty-seven patients underwent ultrasonography followed by radiography, computed tomography (CT) or MRI. Due to its accessibility and safety for the patient ultrasonography allows not only to assess the presence and degree of the degenerative changes in the pulp ous nucleus and disk fibrous ring but also allows to observe the process dynamically

  20. Collagen turnover in normal and degenerate human intervertebral discs as determined by the racemization of aspartic acid

    NARCIS (Netherlands)

    Sivan, S.-S.; Wachtel, E.; Tsitron, E.; Sakkee, N.; Ham, F. van der; Groot, J.de; Roberts, S.; Maroudas, A.

    2008-01-01

    Knowledge of rates of protein turnover is important for a quantitative understanding of tissue synthesis and catabolism. In this work, we have used the racemization of aspartic acid as a marker for the turnover of collagen obtained from healthy and pathological human intervertebral disc matrices. We

  1. Effects of intervertebral disc disorders of low back on the mandibular kinematic: kinesiographic study.

    Science.gov (United States)

    Spadaro, Alessandro; Ciarrocchi, Irma; Masci, Chiara; Cozzolino, Vincenzo; Monaco, Annalisa

    2014-08-26

    Intervertebral disc disorders are one of the most common causes of low back pain. Neuromuscular dysfunction frequently is present in patients with lumbar disc herniation.When considering joint dysfunction, it is important to remember that the spine functions as a unit. Dysfunction on one level can trigger compensatory changes in other spinal levels or in other areas of the musculoskeleton. Findings demonstrated the relationship between stomatognathic and postural systems justifying the hypothesis that muscular-skeletal impairment in one system could affect the other one. However, evidence that a lumbar intervertebral disc herniation could influence the mandibular kinematics is still lacking. Aim of this study was to analyse the effects that intervertebral disc herniation of low back could have on the mandibular kinematics. Kinesiographic evaluations of the mandibular dynamics of 23 adult patients suffering L4/L5 and L5/S1 lumbosacral disc hernation were compared with a non pathological control group. A statistically significant difference of maximal mouth opening (p mandibular kinematics both in rate and quality of movement. The study suggests the existence of connections between masticatory system and lumbar disk herniation.

  2. BACK PAIN ASSOCIATED WITH INTERVERTEBRAL DISK DEGENERATION: MORPHOLOGICAL, GENETIC AND CLINICO-INSTRUMENTAL ASPECTS

    Directory of Open Access Journals (Sweden)

    N. A. Shostak

    2014-07-01

    Full Text Available Degenerative spine disease is one of the causes of back pain. Clinical types of pain and severity of inflammatory changes in the vertebral bodies depend on the activity of pro-inflammatory cytokines. Rate of development and progression of degenerative changes in the spine structures is genetically determined. Therapy of pain syndrome associated with a degenerative disc disease may include use of methods to restore damaged intervertebral disc structures, and also use of different combinations of anti-inflammatory and analgesics therapy.

  3. BACK PAIN ASSOCIATED WITH INTERVERTEBRAL DISK DEGENERATION: MORPHOLOGICAL, GENETIC AND CLINICO-INSTRUMENTAL ASPECTS

    Directory of Open Access Journals (Sweden)

    N. A. Shostak

    2011-01-01

    Full Text Available Degenerative spine disease is one of the causes of back pain. Clinical types of pain and severity of inflammatory changes in the vertebral bodies depend on the activity of pro-inflammatory cytokines. Rate of development and progression of degenerative changes in the spine structures is genetically determined. Therapy of pain syndrome associated with a degenerative disc disease may include use of methods to restore damaged intervertebral disc structures, and also use of different combinations of anti-inflammatory and analgesics therapy.

  4. Avaliação dos resultados clínicos após cirurgia descompressiva em cães com doença de disco intervertebral Evaluation of clinical results of decompressive surgery in dogs with degenerative disk disease

    Directory of Open Access Journals (Sweden)

    M.V.B. Arias

    2007-12-01

    Full Text Available Avaliaram-se os resultados clínicos após realização de cirurgia descompressiva em 45 cães com doença do disco intervertebral cervical ou toracolombar. Após a cirurgia, 35 cães (77,8% recuperaram-se totalmente, oito (17,8% parcialmente e dois (4,4% não apresentaram alteração do quadro inicial. Em oito cães com paraplegia e perda da sensibilidade dolorosa profunda houve completa melhora do quadro clínico, com recuperação total em 62,5% dos casos. Em quatro cães com tetraparesia, a cirurgia foi eficaz. A cirurgia descompressiva (slot cervical e hemilaminectomia toracolombar, com a retirada do material do disco do interior do canal vertebral, foi uma forma efetiva de gerar melhora do quadro funcional.Clinical results after decompressive surgery were evaluated in 45 dogs with cervical or thoracolumbar intervertebral disk disease. After surgery, 35 dogs recovered totally, eight (17.8% partially, and two (4.4% did not present any change in clinical findings. Eight dogs with paraplegy and loss of deep pain perception showed improvement, with total recovering in 62.5% of cases. Surgery was effective in four dogs with tetraparesy. Decompressive surgery (cervical slot or hemilaminectomy, with removal of disk material from inside the vertebral canal, was an effective form to produce functional improvement in dogs with this disease.

  5. In Vivo Mouse Intervertebral Disc Degeneration Model Based on a New Histological Classification.

    Directory of Open Access Journals (Sweden)

    Takashi Ohnishi

    Full Text Available Although human intervertebral disc degeneration can lead to several spinal diseases, its pathogenesis remains unclear. This study aimed to create a new histological classification applicable to an in vivo mouse intervertebral disc degeneration model induced by needle puncture. One hundred six mice were operated and the L4/5 intervertebral disc was punctured with a 35- or 33-gauge needle. Micro-computed tomography scanning was performed, and the punctured region was confirmed. Evaluation was performed by using magnetic resonance imaging and histology by employing our classification scoring system. Our histological classification scores correlated well with the findings of magnetic resonance imaging and could detect degenerative progression, irrespective of the punctured region. However, the magnetic resonance imaging analysis revealed that there was no significant degenerative intervertebral disc change between the ventrally punctured and non-punctured control groups. To induce significant degeneration in the lumbar intervertebral discs, the central or dorsal region should be punctured instead of the ventral region.

  6. Treatment and outcome of herniated lumbar intervertebral disk in a ...

    African Journals Online (AJOL)

    The goal of treatment in cases of lumbar disk herniation is to return the patient to .... instability during surgery on the lumbar spine for the treatment of reherniation ... H. H. Failure within one year following subtotal lumbar discectomy. J Bone ...

  7. Analysis of rabbit intervertebral disc physiology based on water metabolism. II. Changes in normal intervertebral discs under axial vibratory load

    International Nuclear Information System (INIS)

    Hirano, N.; Tsuji, H.; Ohshima, H.; Kitano, S.; Itoh, T.; Sano, A.

    1988-01-01

    Metabolic changes induced by axial vibratory load to the spine were investigated based on water metabolism in normal intervertebral discs of rabbits with or without pentobarbital anesthesia. Tritiated water concentration in the intervertebral discs of unanesthetized rabbits was reduced remarkably by axial vibration for 30 minutes using the vibration machine developed for this study. Repeated vibratory load for 18 and 42 hours duration showed the recovery of 3 H 2 O concentration of the intervertebral disc without anesthesia. Computer simulation suggested a reduction of blood flow surrounding the intervertebral disc following the vibration stress. However, no reduction of the 3 H 2 O concentration in the intervertebral disc was noted under anesthesia. Emotional stress cannot be excluded as a factor in water metabolism in the intervertebral disc

  8. New treatment strategies for canine intervertebral disc degeneration

    NARCIS (Netherlands)

    Smolders, L.A.

    2013-01-01

    Degeneration of the intervertebral disc (IVD) is a common problem in dogs and humans. IVD degeneration can lead to herniation of the IVD with subsequent compression of neural structures and various clinical signs, including back pain. Current treatment of IVD disease is conservative or surgical.

  9. The rat intervertebral disk degeneration pain model: relationships between biological and structural alterations and pain.

    Science.gov (United States)

    Kim, Jae-Sung; Kroin, Jeffrey S; Li, Xin; An, Howard S; Buvanendran, Asokumar; Yan, Dongyao; Tuman, Kenneth J; van Wijnen, Andre J; Chen, Di; Im, Hee-Jeong

    2011-01-01

    Degeneration of the interverterbral disk is as a cause of low-back pain is increasing. To gain insight into relationships between biological processes, structural alterations and behavioral pain, we created an animal model in rats. Disk degeneration was induced by removal of the nucleus pulposus (NP) from the lumbar disks (L4/L5 and L5/L6) of Sprague Dawley rats using a 0.5-mm-diameter microsurgical drill. The degree of primary hyperalgesia was assessed by using an algometer to measure pain upon external pressure on injured lumbar disks. Biochemical and histological assessments and radiographs of injured disks were used for evaluation. We investigated therapeutic modulation of chronic pain by administering pharmaceutical drugs in this animal model. After removal of the NP, pressure hyperalgesia developed over the lower back. Nine weeks after surgery we observed damaged or degenerated disks with proteoglycan loss and narrowing of disk height. These biological and structural changes in disks were closely related to the sustained pain hyperalgesia. A high dose of morphine (6.7 mg/kg) resulted in effective pain relief. However, high doses of pregabalin (20 mg/kg), a drug that has been used for treatment of chronic neuropathic pain, as well as the anti-inflammatory drugs celecoxib (50 mg/kg; a selective inhibitor of cyclooxygenase 2 (COX-2)) and ketorolac (20 mg/kg; an inhibitor of COX-1 and COX-2), did not have significant antihyperalgesic effects in our disk injury animal model. Although similarities in gene expression profiles suggest potential overlap in chronic pain pathways linked to disk injury or neuropathy, drug-testing results suggest that pain pathways linked to these two chronic pain conditions are mechanistically distinct. Our findings provide a foundation for future research on new therapeutic interventions that can lead to improvements in the treatment of patients with back pain due to disk degeneration.

  10. Laser biostimulation effects on invertebral disks: histological evidence on intra-observer samples. Retrospective double-blind study.

    Science.gov (United States)

    Tramontana, Alfonso; Sorge, Roberto; Page, Juan Carlos Miangolarra

    2016-12-30

    Background and aims: The intervertebral disk degeneration is a pathological process determined by a decrease of mucopolysaccharides in the nucleus pulposus with the consequent dehydration and degeneration of the elastic fibers in the annulus fibrosus of the disk. The laser is a therapeutic tool that has, on the treated tissues, biostimulation effects with an increase of oxidative phosphorylation and production of ATP with an acceleration of the mucopolysaccharides synthesis with a consequent rehydration, biostimulation and production of new elastic fibers. The goal of this project is studying whether the laser stimulation may treat degenerated intervertebral disks. Materials and methods: 60 subjects with the same anthropometric parameters were selected and divided into two randomized groups. 30 subjects underwent laser stimulation, whereas 30 underwent placebo. All 60 subjects underwent a discectomy surgery and the intraoperative findings were examined in a lab, studying the positivity of the PAS reaction and the presence of potential newly formed elastic fibers. Results: It has been shown a higher number of mucopolysaccharides and young newly formed elastic fibers in the group that was treated with laser irradiation with a statistically significant difference, compared to the placebo group (pdisks.

  11. Spectroscopic Parameters of Lumbar Intervertebral Disc Material

    Science.gov (United States)

    Terbetas, G.; Kozlovskaja, A.; Varanius, D.; Graziene, V.; Vaitkus, J.; Vaitkuviene, A.

    2009-06-01

    There are numerous methods of investigating intervertebral disc. Visualization methods are widely used in clinical practice. Histological, imunohistochemical and biochemical methods are more used in scientific research. We propose that a new spectroscopic investigation would be useful in determining intervertebral disc material, especially when no histological specimens are available. Purpose: to determine spectroscopic parameters of intervertebral disc material; to determine emission spectra common for all intervertebral discs; to create a background for further spectroscopic investigation where no histological specimen will be available. Material and Methods: 20 patients, 68 frozen sections of 20 μm thickness from operatively removed intervertebral disc hernia were excited by Nd:YAG microlaser STA-01-TH third harmonic 355 nm light throw 0, 1 mm fiber. Spectrophotometer OceanOptics USB2000 was used for spectra collection. Mathematical analysis of spectra was performed by ORIGIN multiple Gaussian peaks analysis. Results: In each specimen of disc hernia were found distinct maximal spectral peaks of 4 types supporting the histological evaluation of mixture content of the hernia. Fluorescence in the spectral regions 370-700 nm was detected in the disc hernias. The main spectral component was at 494 nm and the contribution of the components with the peak wavelength values at 388 nm, 412 nm and 435±5 nm were varying in the different groups of samples. In comparison to average spectrum of all cases, there are 4 groups of different spectral signatures in the region 400-500 nm in the patient groups, supporting a clinical data on different clinical features of the patients. Discussion and Conclusion: besides the classical open discectomy, new minimally invasive techniques of treating intervertebral disc emerge (PLDD). Intervertebral disc in these techniques is assessed by needle, no histological specimen is taken. Spectroscopic investigation via fiber optics through the

  12. Acquired degenerative changes of the intervertebral segments at and suprajacent to the lumbosacral junction. A radioanatomic analysis of the nondiskal structures of the spinal column and perispinal soft tissues.

    Science.gov (United States)

    Jinkins, J R

    2001-01-01

    In earlier evolutionary times, mammals were primarily quadrupeds. However, other bipeds have also been represented during the course of the Earth's several billion year history. In many cases, either the bipedal stance yielded a large tail and hypoplastic upper extremities (e.g., Tyrannosaurus rex and the kangaroo), or it culminated in hypoplasia of the tail and further development and specialization of the upper extremities (e.g., nonhuman primates and human beings). In the human species this relatively recently acquired posture resulted in a more or less pronounced lumbosacral kyphosis. In turn, certain compensatory anatomic features have since occurred. These include the normal characteristic posteriorly directed wedge-shape of the L5 vertebral body and the L5-S1 intervertebral disk; the L4 vertebral body and the L4-L5 disk may be similarly visibly affected. These compensatory mechanisms, however, have proved to be functionally inadequate over the long term of the human life span. Upright posture also leads to increased weight bearing in humans that progressively causes excess stresses at and suprajacent to the lumbosacral junction. These combined factors result in accelerated aging and degenerative changes and a predisposition to frank biomechanical failure of the subcomponents of the spinal column in these spinal segments. One other specific problem that occurs at the lumbosacral junction that predisposes toward premature degeneration is the singular relationship that exists between a normally mobile segment of spine (i.e., the lumbar spine) and a normally immobile one (i.e., the sacrum). It is well known that mobile spinal segments adjacent to congenitally or acquired fused segments have a predilection toward accelerated degenerative changes. The only segment of the spine in which this is invariably normally true is at the lumbosacral junction (i.e., the unfused lumbar spine adjoining the fused sacrum). Nevertheless, biomechanical failures of the human spine

  13. Magnetic resonance imaging of intervertebral disc degeneration

    International Nuclear Information System (INIS)

    Maeda, Hiroshi; Noguchi, Masao; Kira, Hideaki; Fujiki, Hiroshi; Shimokawa, Isao; Hinoue, Kaichi.

    1993-01-01

    The aim of this study was to correlate the degree of lumbar intervertebral disc degeneration with findings of magnetic resonance imaging (MRI). Seventeen autopsied (from 7 patients) and 21 surgical (from 20 patients) intervertebral discs were used as specimens for histopathological examination. In addition, 21 intervertebral discs were examined on T2-weighted images. Histopathological findings from both autopsied and surgical specimens were well correlated with MRI findings. In particular, T2-weighted images reflected increased collagen fibers and rupture within the fibrous ring accurately. However, when severely degenerated intervertebral discs and hernia protruding the posterior longitudinal ligament existed, histological findings were not concordant well with T2-weighted images. Morphological appearances of autopsy specimens, divided into four on T2-weighted images, were well consistent with histological degeneration. This morphological classification, as shown on T2-weighted images, could also be used in the evaluation of intervertebral disc degeneration. (N.K.)

  14. Magnetic resonance imaging of intervertebral disc degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Hiroshi; Noguchi, Masao (Kitakyushu City Yahata Hospital, Fukuoka (Japan)); Kira, Hideaki; Fujiki, Hiroshi; Shimokawa, Isao; Hinoue, Kaichi

    1993-02-01

    The aim of this study was to correlate the degree of lumbar intervertebral disc degeneration with findings of magnetic resonance imaging (MRI). Seventeen autopsied (from 7 patients) and 21 surgical (from 20 patients) intervertebral discs were used as specimens for histopathological examination. In addition, 21 intervertebral discs were examined on T2-weighted images. Histopathological findings from both autopsied and surgical specimens were well correlated with MRI findings. In particular, T2-weighted images reflected increased collagen fibers and rupture within the fibrous ring accurately. However, when severely degenerated intervertebral discs and hernia protruding the posterior longitudinal ligament existed, histological findings were not concordant well with T2-weighted images. Morphological appearances of autopsy specimens, divided into four on T2-weighted images, were well consistent with histological degeneration. This morphological classification, as shown on T2-weighted images, could also be used in the evaluation of intervertebral disc degeneration. (N.K.).

  15. Investigation of the in-vitro loading on an artificial spinal disk prosthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kyriacou, P A; Pancholi, M P [School of Engineering and Mathematical Sciences, City University London (United Kingdom); Yeh, J, E-mail: P.Kyriacou@city.ac.u [Department of Neurosurgery, Royal London Hospital, Barts and the London NHS Trust, London (United Kingdom)

    2009-07-01

    Spinal diseases imposes considerable burden to both patients and society. In recent years, much surgical efforts have been made in advancing the treatment of neck and back pain. Of particular prominence is the increasing clinical acceptance and use of intervertebral artificial disk prosthesis for the treatment of discogenic back pain. Despite this increased use of such disks, their in-vivo monitoring remains rudimentary. In an effort to develop an intelligent artificial spinal disk where the in-vivo loading of the spine can by studied for the first time an experimental set up has been created in order to initially study the in-vitro loading on an artificial disc prosthesis. Eight strain gauges and two piezoresistive sensors were used and placed suitably in the artificial disk prosthesis. The results from the in-vitro loading showed linear relationship between loading and the outputs from the sensors with good repeatability and less hysteresis.

  16. Investigation of the in-vitro loading on an artificial spinal disk prosthesis

    International Nuclear Information System (INIS)

    Kyriacou, P A; Pancholi, M P; Yeh, J

    2009-01-01

    Spinal diseases imposes considerable burden to both patients and society. In recent years, much surgical efforts have been made in advancing the treatment of neck and back pain. Of particular prominence is the increasing clinical acceptance and use of intervertebral artificial disk prosthesis for the treatment of discogenic back pain. Despite this increased use of such disks, their in-vivo monitoring remains rudimentary. In an effort to develop an intelligent artificial spinal disk where the in-vivo loading of the spine can by studied for the first time an experimental set up has been created in order to initially study the in-vitro loading on an artificial disc prosthesis. Eight strain gauges and two piezoresistive sensors were used and placed suitably in the artificial disk prosthesis. The results from the in-vitro loading showed linear relationship between loading and the outputs from the sensors with good repeatability and less hysteresis.

  17. Vascular complications of prosthetic inter-vertebral discs

    OpenAIRE

    Daly, Kevin J.; Ross, E. Raymond S.; Norris, Heather; McCollum, Charles N.

    2006-01-01

    Five consecutive cases of prosthetic inter-vertebral disc displacement with severe vascular complications on revisional surgery are described. The objective of this case report is to warn spinal surgeons that major vascular complications are likely with anterior displacement of inter-vertebral discs. We have not been able to find a previous report on vascular complications associated with anterior displacement of prosthetic inter-vertebral discs. In all five patients the prosthetic disc had e...

  18. Poroelastic behaviour of the degenerating human intervertebral disc: a ten-day study in a loaded disc culture system

    NARCIS (Netherlands)

    Emanuel, K. S.; Vergroesen, P.-P. A.; Peeters, M.; Holewijn, R. M.; Kingma, I.; Smit, T. H.

    2015-01-01

    The intervertebral disc (IVD) allows flexibility to the vertebral column, and transfers the predominant axial loads during daily activities. Its axial biomechanical behaviour is poroelastic, due to the water-binding and releasing capacity of the nucleus pulposus. Degeneration of the intervertebral

  19. Angiogenesis in the degeneration of the lumbar intervertebral disc

    OpenAIRE

    David, Gh; Ciurea, AV; Iencean, SM; Mohan, A

    2010-01-01

    The goal of the study is to show the histological and biochemical changes that indicate the angiogenesis of the intervertebral disc in lumbar intervertebral disc hernia and the existence of epidemiological correlations between these changes and the risk factors of lumbar intervertebral disc hernia, as well as the patient's quality of life (QOL). We have studied 50 patients aged between 18 and 73 years old, who have undergone lumbar intervertebral disc hernia surgery, making fibroblast growth ...

  20. Biomaterials for intervertebral disc regeneration and repair.

    Science.gov (United States)

    Bowles, Robert D; Setton, Lori A

    2017-06-01

    The intervertebral disc contributes to motion, weight bearing, and flexibility of the spine, but is susceptible to damage and morphological changes that contribute to pathology with age and injury. Engineering strategies that rely upon synthetic materials or composite implants that do not interface with the biological components of the disc have not met with widespread use or desirable outcomes in the treatment of intervertebral disc pathology. Here we review bioengineering advances to treat disc disorders, using cell-supplemented materials, or acellular, biologically based materials, that provide opportunity for cell-material interactions and remodeling in the treatment of intervertebral disc disorders. While a field still in early development, bioengineering-based strategies employing novel biomaterials are emerging as promising alternatives for clinical treatment of intervertebral disc disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. [Treatment of lumbar intervertebral disc displacement with chondroitinase ABC--experimental basis for clinical application].

    Science.gov (United States)

    Takahashi, Toyomi

    2004-07-01

    After single intradiscal injection of C-ABC in rabbit inter-vertebral discs, water content in the matrix of nucleus pulposus diminished clearly. After similar injection of C-ABC in sheep discs, disc inner pressure was diminished. After single intradiscal injection of C-ABC in dog inter-vertebral discs suffering disc herniation, the syndromes coming from the herniation diminished or disappeared. Based on these observations C-ABC is expected to be a chemonucleolytic agent and a human clinical trial is now in progress.

  2. Finite element based nonlinear normalization of human lumbar intervertebral disc stiffness to account for its morphology.

    Science.gov (United States)

    Maquer, Ghislain; Laurent, Marc; Brandejsky, Vaclav; Pretterklieber, Michael L; Zysset, Philippe K

    2014-06-01

    Disc degeneration, usually associated with low back pain and changes of intervertebral stiffness, represents a major health issue. As the intervertebral disc (IVD) morphology influences its stiffness, the link between mechanical properties and degenerative grade is partially lost without an efficient normalization of the stiffness with respect to the morphology. Moreover, although the behavior of soft tissues is highly nonlinear, only linear normalization protocols have been defined so far for the disc stiffness. Thus, the aim of this work is to propose a nonlinear normalization based on finite elements (FE) simulations and evaluate its impact on the stiffness of human anatomical specimens of lumbar IVD. First, a parameter study involving simulations of biomechanical tests (compression, flexion/extension, bilateral torsion and bending) on 20 FE models of IVDs with various dimensions was carried out to evaluate the effect of the disc's geometry on its compliance and establish stiffness/morphology relations necessary to the nonlinear normalization. The computed stiffness was then normalized by height (H), cross-sectional area (CSA), polar moment of inertia (J) or moments of inertia (Ixx, Iyy) to quantify the effect of both linear and nonlinear normalizations. In the second part of the study, T1-weighted MRI images were acquired to determine H, CSA, J, Ixx and Iyy of 14 human lumbar IVDs. Based on the measured morphology and pre-established relation with stiffness, linear and nonlinear normalization routines were then applied to the compliance of the specimens for each quasi-static biomechanical test. The variability of the stiffness prior to and after normalization was assessed via coefficient of variation (CV). The FE study confirmed that larger and thinner IVDs were stiffer while the normalization strongly attenuated the effect of the disc geometry on its stiffness. Yet, notwithstanding the results of the FE study, the experimental stiffness showed consistently

  3. Vascular complications of prosthetic inter-vertebral discs.

    Science.gov (United States)

    Daly, Kevin J; Ross, E Raymond S; Norris, Heather; McCollum, Charles N

    2006-10-01

    Five consecutive cases of prosthetic inter-vertebral disc displacement with severe vascular complications on revisional surgery are described. The objective of this case report is to warn spinal surgeons that major vascular complications are likely with anterior displacement of inter-vertebral discs. We have not been able to find a previous report on vascular complications associated with anterior displacement of prosthetic inter-vertebral discs. In all five patients the prosthetic disc had eroded into the bifurcation of the inferior vena cava and the left common iliac vein. In three cases the aortic bifurcation was also involved. The fibrosis was so severe that dissecting out the arteries and veins to provide access to the relevant disc proved impossible. Formal division of the left common iliac vein and artery with subsequent repair was our solution. Anterior inter-vertebral disc displacement was associated with severe vascular injury. Preventing anterior disc displacement is essential in disc design. In the event of anterior displacement, disc removal should be planned with a Vascular Surgeon.

  4. Oxidative stress participates in age-related changes in rat lumbar intervertebral discs.

    Science.gov (United States)

    Hou, Gang; Lu, Huading; Chen, Mingjuan; Yao, Hui; Zhao, Huiqing

    2014-01-01

    Aging is a major factor associated with lumber intervertebral disc degeneration, and oxidative stress is known to play an essential role in the pathogenesis of many age-related diseases. In this study, we investigated oxidative stress in intervertebral discs of Wistar rats in three different age groups: youth, adult, and geriatric. Age-related intervertebral disc changes were examined by histological analysis. In addition, oxidative stress was evaluated by assessing nitric oxide (NO), superoxide dismutase (SOD), malondialdehyde (MDA), and advanced oxidation protein products (AOPPs). Intervertebral disc, but not serum, NO concentrations significantly differed between the three groups. Serum and intervertebral disc SOD activity gradually decreased with age. Furthermore, both serum and intervertebral disc MDA and AOPP levels gradually increased with age. Our studies suggest that oxidative stress is associated with age-related intervertebral disc changes. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. Cisto intraespinal em comunicação com o disco intervertebral na coluna lombar: relato de um caso e revisão da literatura Quiste intraespinhal en comunicación con el disco intervertebral em la columna lumbar: reporte de caso y revisión de la literatura Intraspinal cyst communicating with the intervertebral disk in the lumbar spine: case report and literature review

    Directory of Open Access Journals (Sweden)

    Mauricio Marteleto Filho

    2012-12-01

    ículo se describen las características de esta entidad clínica, incluyendo el aspecto clínico, radiológico e histológico, para discutir la posible patogénesis y tratamiento.Herniated lumbar disc is an important as well as the most common cause of low back pain and sciatica. Many cases can be readily diagnosed by simple semiological examination. Magnetic resonance imaging (MRI provides a definitive diagnosis even in an outpatient basis. Several types of intraspinal cysts with different pathogenesis have been reported in the past, such as perineural cysts, synovial cysts, arachnoid cysts, and ganglion cysts, diseases that are difficult to differentiate from lumbar disc herniation. Recently, the authors have observed one case of intraspinal cyst communicating with the corresponding intervertebral disk, presenting clinical symptoms, signs, and even some radiographic findings undistinguishable from those of herniated disks. The diagnosis established by MRI and confirmed at surgery. This paper describes the features of this distinct clinical condition, including clinical findings, images, and histological aspects, to discuss possible pathogenesis and management.

  6. Mechanical Characterization of the Human Lumbar Intervertebral Disc Subjected to Impact Loading Conditions

    Science.gov (United States)

    Jamison, David, IV

    Low back pain is a large and costly problem in the United States. Several working populations, such as miners, construction workers, forklift operators, and military personnel, have an increased risk and prevalence of low back pain compared to the general population. This is due to exposure to repeated, transient impact shocks, particularly while operating vehicles or other machinery. These shocks typically do not cause acute injury, but rather lead to pain and injury over time. The major focus in low back pain is often the intervertebral disc, due to its role as the major primary load-bearing component along the spinal column. The formation of a reliable standard for human lumbar disc exposure to repeated transient shock could potentially reduce injury risk for these working populations. The objective of this project, therefore, is to characterize the mechanical response of the lumbar intervertebral disc subjected to sub-traumatic impact loading conditions using both cadaveric and computational models, and to investigate the possible implications of this type of loading environment for low back pain. Axial, compressive impact loading events on Naval high speed boats were simulated in the laboratory and applied to human cadaveric specimen. Disc stiffness was higher and hysteresis was lower than quasi-static loading conditions. This indicates a shift in mechanical response when the disc is under impact loads and this behavior could be contributing to long-term back pain. Interstitial fluid loss and disc height changes were shown to affect disc impact mechanics in a creep study. Neutral zone increased, while energy dissipation and low-strain region stiffness decreased. This suggests that the disc has greater clinical instability during impact loading with progressive creep and fluid loss, indicating that time of day should be considered for working populations subjected to impact loads. A finite element model was developed and validated against cadaver specimen

  7. [Meniscoids of the intervertebral joints].

    Science.gov (United States)

    Kos, J; Hert, J; Sevcík, P

    2002-01-01

    A large amount of material was used to study the distribution, location and shape of meniscoids in intervertebral joints of the human spine, from the atlanto-occipital joint to the sacrum, in order to find out how many of intervertebral joints had mobile meniscoids. These might be regarded as possible causes of spinal blockade or other vertebrogenous complaints. The materials provided by the Department of Anatomy and Department of Forensic Medicine at the Faculty of Medicine of Charles University in Pilznen included 20 cadaverous spines from humans aged 20 to 80 years. Access to each joint was provided by dissection of the articular capsule from the lower articular processes of the vertebra situated above. In the orthograde view, all meniscoids were described in terms of shape, size, consistence and location. Their structure was ascertained by histological examination of cross sections stained with haematoxylin and eosin. Meniscoids varying in shape and size were found in all of the intervertebral joints. They were classified by their histological structure as synovial, fat and fibrous meniscoids. The first category was observed frequently, the last only rarely. A total of 29 mobile meniscoids were recorded, most of them in the lumbar spine. Most of the meniscoids present in the cervical spine were of synovial and less frequently of fat types. Meniscoids found in the thoracic spine were poorly developed synovial ones and those present in the lumbar spine were of all types and were also largest in size. The most conspicuous meniscoids were seen in the spines that showed degenerative changes in intervertebral joints. Large fat pads were found in atlanto-occipital and atlanto-axial joints. Mobile meniscoids, most of them present in the lumbar spine (6.4% of all joints.), were connected with the capsule by a thin pedicle and it was possible to move them over a half of the articular surface. Some inter-individual changes were also found; in some spines, the most

  8. Nonlinear dynamics of the human lumbar intervertebral disc.

    Science.gov (United States)

    Marini, Giacomo; Huber, Gerd; Püschel, Klaus; Ferguson, Stephen J

    2015-02-05

    Systems with a quasi-static response similar to the axial response of the intervertebral disc (i.e. progressive stiffening) often present complex dynamics, characterized by peculiar nonlinearities in the frequency response. However, such characteristics have not been reported for the dynamic response of the disc. The accurate understanding of disc dynamics is essential to investigate the unclear correlation between whole body vibration and low back pain. The present study investigated the dynamic response of the disc, including its potential nonlinear response, over a range of loading conditions. Human lumbar discs were tested by applying a static preload to the top and a sinusoidal displacement at the bottom of the disc. The frequency of the stimuli was set to increase linearly from a low frequency to a high frequency limit and back down. In general, the response showed nonlinear and asymmetric characteristics. For each test, the disc had different response in the frequency-increasing compared to the frequency-decreasing sweep. In particular, the system presented abrupt changes of the oscillation amplitude at specific frequencies, which differed between the two sweeps. This behaviour indicates that the system oscillation has a different equilibrium condition depending on the path followed by the stimuli. Preload and amplitude of the oscillation directly influenced the disc response by changing the nonlinear dynamics and frequency of the jump-phenomenon. These results show that the characterization of the dynamic response of physiological systems should be readdressed to determine potential nonlinearities. Their direct effect on the system function should be further investigated. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Degenerated human intervertebral discs contain autoantibodies against extracellular matrix proteins

    Directory of Open Access Journals (Sweden)

    S Capossela

    2014-04-01

    Full Text Available Degeneration of intervertebral discs (IVDs is associated with back pain and elevated levels of inflammatory cells. It has been hypothesised that discogenic pain is a direct result of vascular and neural ingrowth along annulus fissures, which may expose the avascular nucleus pulposus (NP to the systemic circulation and induce an autoimmune reaction. In this study, we confirmed our previous observation of antibodies in human degenerated and post-traumatic IVDs cultured in vitro. We hypothesised that the presence of antibodies was due to an autoimmune reaction against specific proteins of the disc. Furthermore we identified antigens which possibly trigger an autoimmune response in degenerative disc diseases. We demonstrated that degenerated and post-traumatic IVDs contain IgG antibodies against typical extracellular proteins of the disc, particularly proteins of the NP. We identified IgGs against collagen type II and aggrecan, confirming an autoimmune reaction against the normally immune privileged NP. We also found specific IgGs against collagens types I and V, but not against collagen type III. In conclusion, this study confirmed the association between disc degeneration and autoimmunity, and may open the avenue for future studies on developing prognostic, diagnostic and therapy-monitoring markers for degenerative disc diseases.

  10. Significance of human retinal optic disk localization in various retinal eye diseases

    International Nuclear Information System (INIS)

    Basit, A.

    2011-01-01

    Optic Disk is one of the prominent features in human fundus images. Automatic localization and segmentation of optic disk can help in early diagnosis of diabetic retinopathies and preventing vision loss. In this paper robust method for optic disk detection and extraction of optic disk boundary is proposed based on morphological operations, smoothing filters and markers controlled watershed transform. This method has shown significant improvements in terms of detection and boundaries extraction of optic disk. This method used two types of markers: internal marker and external marker. These markers first modified the gradient magnitude image and then watershed transformation is applied on this modified gradient magnitude image for boundary extraction. The proposed method has optic disk detection success rate of 100% for Shifa and 87.6% for DIARETDB1 databases. Proposed method achieved average overlap of 51.19% for DIARETDB1 database and 73.98% for Shifa database which is higher than currents methods. Experimental results clearly demonstrate an efficient performance of the proposed algorithm. (author)

  11. Mechanical properties of human articular disk and its influence on TMJ loading studied with the finite element method.

    Science.gov (United States)

    Tanaka, E; Sasaki, A; Tahmina, K; Yamaguchi, K; Mori, Y; Tanne, K

    2001-03-01

    The present study was designed to investigate the elastic modulus of human temporomandibular joint (TMJ) disk under tension and its influences on TMJ loading. Seven human TMJ disks served as specimens. Continuous tensile stress was applied to each specimen, and the elastic moduli of human TMJ disks were calculated at 2% strain. Furthermore, using a three-dimensional finite element model of the mandible including the TMJ, changes in the TMJ stresses during clenching were evaluated in association of varying elastic moduli of the articular disk determined by the tensile tests. The elastic moduli at 2% strain varied from 27.1 to 65.2 MPa with a mean of 47.1 MPa. A significant correlation was found between the elastic moduli and age (P elastic moduli of the TMJ disk was varied from 25 to 65 MPa. In the TMJ disk, shear stresses in all the areas became larger with greater stiffness. In conclusion, it is shown that the elastic modulus of human TMJ disk is increased with age and that higher stiffness of the disk exerts substantial influences on mechanical loading for the TMJ structures.

  12. FoxC2 Enhances BMP7-Mediated Anabolism in Nucleus Pulposus Cells of the Intervertebral Disc

    OpenAIRE

    Wang, Zheng; Fu, Changfeng; Chen, Yong; Xu, Feng; Wang, Zhenyu; Qu, Zhigang; Liu, Yi

    2016-01-01

    Bone-morphogenetic protein-7 (BMP-7) is a growth factor that plays a major role in mediating anabolism and anti-catabolism of the intervertebral disc matrix and cell homeostasis. In osteoblasts, Forkhead box protein C2 (FoxC2) is a downstream target of BMPs and promotes cell proliferation and differentiation. However, the role FoxC2 may play in degenerative human intervertebral disc tissue and the relationship between FoxC2 and BMP-7 in nucleus pulposus (NP) cells remain to be elucidated. Thi...

  13. The presence and absence of lymphatic vessels in the adult human intervertebral disc: relation to disc pathology

    International Nuclear Information System (INIS)

    Kliskey, Karolina; Williams, Kelly; Yu, J.; Urban, Jill; Athanasou, Nick; Jackson, David

    2009-01-01

    Although the normal adult human intervertebral disc is considered to be avascular, vascularised cellular fibrous tissue can be found in pathological conditions involving the disc such as disc herniation. Whether lymphatics vessels form a component of this reparative tissue is not known as the presence or absence of lymphatics in herniated and normal disc tissue is not known. We examined spinal tissues and discectomy specimens for the presence of lymphatics. The examination used immunohistochemistry to identify the specific lymphatic endothelial cell markers, podoplanin and LYVE1. Lymphatic vessels were not found in the nucleus pulposus or annulus fibrosus of intact, non-herniated lumbar and thoracic discs but were present in the surrounding ligaments. Ingrowth of fibrous tissue was seen in 73% of herniated disc specimens of which 36% contained LYVE1+/podoplanin + lymphatic vessels. Lymphatic vessels were not seen in the sacrum and coccyx or biopsies of four sacrococcygeal chordomas, but they were noted in surrounding extra-osseous fat and fibrous tissue at the edge of the infiltrating tumour. Our findings indicate that lymphatic vessels are not present in the normal adult intervertebral disc but that, when there is extrusion of disc material into surrounding soft tissue, there is ingrowth of reparative fibrous tissue containing lymphatic vessels. Our findings also indicate that chordoma, a tumour of notochordal origin, spreads to regional lymph nodes via lymphatics in para-spinal soft tissues. (orig.)

  14. A CLINICAL STUDY OF OPERATIVE TREATMENT FOR LUMBAR INTERVERTEBRAL DISC PROLAPSE

    Directory of Open Access Journals (Sweden)

    Anilkumar S. D

    2016-09-01

    Full Text Available BACKGROUND Amongst painful diseases, sciatica occupies a foremost place by reason of its prevalence, its production by a great variety of conditions, the great disablement it may produce and its tending to relapse all of which have led to its recognition as one of the great scourges of humanity. Intervertebral disc prolapse is the important and common cause of low back pain and sciatica. Here, the subject of laminectomy and discectomy in the treatment of proven intervertebral disc prolapse in the lower lumbar region is reviewed and its results examined. AIM OF STUDY This study was undertaken in order to evaluate the following objectives. PRIMARY Analysis of clinical parameters and per operative findings of lumbar intervertebral disc prolapse. SECONDARY Analysis of clinical parameters and surgical outcome in lumbar intervertebral disc prolapse with respect to improvement in pain and neurological status. MATERIALS AND METHODS The study was undertaken in 22 patients who attended the Orthopaedic Department of Mount Zion Medical College, Adoor, between August 2014 to July 2015. All of them were suffering from a prolapsed lumbar vertebral disc as shown by clinical examination and investigations. Lumbar laminectomy and discectomy constituted the operative procedure for all of them. RESULTS In acute onset cases and cases with short duration, results were good. By six months, 80% of patients recorded of good pain relief, 80% of patients returned to work within six 6 months, 60% of patients showed good neurological recovery by 6 months. Laminectomy and discectomy in proven cases of lumbar intervertebral disc prolapse is a rewarding procedure. LT definitely relieved pain in all cases and improved morbidity and neurological deficits in most of the cases. CONCLUSION 1. Laminectomy and discectomy is an effective method of treatment in herniation of lumbar intervertebral disc. 2. The procedure is ideally done in those with the disc prolapse proved with the

  15. Structural behavior of human lumbar intervertebral disc under direct shear.

    Science.gov (United States)

    Schmidt, Hendrik; Häussler, Kim; Wilke, Hans-Joachim; Wolfram, Uwe

    2015-03-18

    The intervertebral disc (IVD) is a complex, flexible joint between adjacent vertebral bodies that provides load transmission while permitting movements of the spinal column. Finite element models can be used to help clarify why and how IVDs fail or degenerate. To do so, it is of importance to validate those models against controllable experiments. Due to missing experimental data, shear properties are not used thus far in validating finite element models. This study aimed to investigate the structural shear properties of human lumbar IVDs in posteroanterior (PA) and laterolateral (LL) loading directions. Fourteen lumbar IVDs (median age: 49 years) underwent direct shear in PA and LL loading directions. A custom-build shear device was used in combination with a materials testing machine to load the specimens until failure. Shear stiffness, ultimate shear force and displacement, and work to failure were determined. Each specimen was tested until complete or partial disruption. Median stiffness in PA direction was 490 N/mm and in LL direction 568 N/mm. Median ultimate shear force in the PA direction was 2,877 N and in the LL direction 3,199 N. Work to failure was 12 Nm in the PA and 9 Nm in the LL direction. This study was an experiment to subject IVDs to direct shear. The results could help us to understand the structure and function of IVDs with regard to mechanical spinal stability, and they can be used to validate finite element models of the IVD.

  16. A method for quantitative measurement of lumbar intervertebral disc structures

    DEFF Research Database (Denmark)

    Tunset, Andreas; Kjær, Per; Samir Chreiteh, Shadi

    2013-01-01

    There is a shortage of agreement studies relevant for measuring changes over time in lumbar intervertebral disc structures. The objectives of this study were: 1) to develop a method for measurement of intervertebral disc height, anterior and posterior disc material and dural sac diameter using MR...

  17. Effect of Degeneration on Fluid-Solid Interaction within Intervertebral Disk Under Cyclic Loading - A Meta-Model Analysis of Finite Element Simulations.

    Science.gov (United States)

    Nikkhoo, Mohammad; Khalaf, Kinda; Kuo, Ya-Wen; Hsu, Yu-Chun; Haghpanahi, Mohammad; Parnianpour, Mohamad; Wang, Jaw-Lin

    2015-01-01

    The risk of low back pain resulted from cyclic loadings is greater than that resulted from prolonged static postures. Disk degeneration results in degradation of disk solid structures and decrease of water contents, which is caused by activation of matrix digestive enzymes. The mechanical responses resulted from internal solid-fluid interactions of degenerative disks to cyclic loadings are not well studied yet. The fluid-solid interactions in disks can be evaluated by mathematical models, especially the poroelastic finite element (FE) models. We developed a robust disk poroelastic FE model to analyze the effect of degeneration on solid-fluid interactions within disk subjected to cyclic loadings at different loading frequencies. A backward analysis combined with in vitro experiments was used to find the elastic modulus and hydraulic permeability of intact and enzyme-induced degenerated porcine disks. The results showed that the averaged peak-to-peak disk deformations during the in vitro cyclic tests were well fitted with limited FE simulations and a quadratic response surface regression for both disk groups. The results showed that higher loading frequency increased the intradiscal pressure, decreased the total fluid loss, and slightly increased the maximum axial stress within solid matrix. Enzyme-induced degeneration decreased the intradiscal pressure and total fluid loss, and barely changed the maximum axial stress within solid matrix. The increase of intradiscal pressure and total fluid loss with loading frequency was less sensitive after the frequency elevated to 0.1 Hz for the enzyme-induced degenerated disk. Based on this study, it is found that enzyme-induced degeneration decreases energy attenuation capability of disk, but less change the strength of disk.

  18. The impact of the artificial intervertebral disc on functioning the lumbar spine

    Directory of Open Access Journals (Sweden)

    Mańsko M.

    2015-12-01

    Full Text Available In the hereby thesis the anatomy of the lumbar vertebra and intervertebral disc were presented. Functioning and kinematics of the spine and intervertebral forces were described.Full three – dimensional model of the lumbar vertebrae L2 – L4 was created. On the basis of it model of artificial intervertebral disc was constructed (between L2 and L3. The simplified model of vertebra L2 was formulated via finite elements method. Processed model has been used for biomechanical analysis.Strength calculations were made and appropriate conclusions were drawn. Presented results show behavior influenced of three – dimensional model of the lumbar vertebra with artificial intervertebral disc by operation of loads.

  19. The Changes in the Expression of NF-KB in a Degenerative Human Intervertebral Disc model.

    Science.gov (United States)

    Sun, Zhongyi; Yin, Zhanmin; Liu, Chao; Tian, Jiwei

    2015-05-01

    We aim at determining the changes in the expression of NF-kB signaling pathway in degenerative intervertebral discs. We collected normal and degenerated intervertebral discs tissues. The normal and degenerated cells were cultivated and their histopathology and immunofluoresence studies were used to observe the position of NF-kB p65 in the cell. We also treated the nucleus pulposus cells with inflammatory factors and inhibitors. Western blot was used to analyze the expression of different proteins. Real time fluorescence-based quantitative PCR was used for observation of NF-kB regulation of change in gene expression. Immunofluorescence showed that in the non-degenerative group the p65 was found in the cytoplasm of the nucleus pulposus cell while in the degenerated cell group the p65 protein was found in the nucleus of the cell. The expression of p65 increased with increase in the degree of degenerative change of the nucleus pulposus cell. RT-PCR showed that the expression of matrix metalloproteinases, aggrecanases and IL-6 was higher in the degenerative group. The amount of aggrecan and type II collagen was significantly decreased in the degenerative group. IL-1β was able to upregulate the activation of NF-kB and the expression of MMP-13 and ADAMTS-4 was also significantly increased. The effect of these proteins can be inhibited by the NF-kB inhibitor, BAY11-7082. The activation of the NK-kB signaling pathway in a degenerative intervertebral disc is gradually increased, regulating the over-expression of matrix-degrading enzymes. It plays an important role in the degradation of extracellular matrix.

  20. Auto fluorescence of intervertebral disc tissue: a new diagnostic tool.

    Science.gov (United States)

    Hoell, T; Huschak, G; Beier, A; Hüttmann, G; Minkus, Y; Holzhausen, H J; Meisel, H J

    2006-08-01

    The paper reports on auto fluorescence phenomena of inter-vertebral human discs. It systematically investigates the auto fluorescence effects of ex vivo disc specimen and reports on surgical cases to demonstrate the potential value of the new method. The paper offers biologic explanations of the phenomenon and discusses the potential value of the UV auto fluorescence technique as a diagnostic tool. Intra- and postoperative observations are made by a surgical microscope with an integrated UV light source. Quantitative measurements were carried out using a photon counter and a spectrometer ex vivo. The auto fluorescence phenomenon allows the differentiation of traumatized and degenerated disc tissue intraoperatively in some cases, it allows the differentiation of bony and collagen endplate in cervical disc surgery. The source of the auto fluorescent light emission are amino acids of the collagen molecules. The proteoglycan components and the liquid components of the disc do not show relevant auto fluorescence. Emission wavelength of disc material is equivalent to color perception. It differs due to different collagen composition of the intervertebral disc components from yellow-green to blue-green and can be visualized in situ by naked eye.UV-auto fluorescence of inter-vertebral discs is a new clinical tool that has the potential to differentiate disc material from the anatomical surrounding, to distinguish between different fractions of the disc and to give information on the quality and status of the disc material. Since the technology has just emerged, it needs further investigations to quantify the clinical observations reported in this paper.

  1. Notochord Cells in Intervertebral Disc Development and Degeneration

    Science.gov (United States)

    McCann, Matthew R.; Séguin, Cheryle A.

    2016-01-01

    The intervertebral disc is a complex structure responsible for flexibility, multi-axial motion, and load transmission throughout the spine. Importantly, degeneration of the intervertebral disc is thought to be an initiating factor for back pain. Due to a lack of understanding of the pathways that govern disc degeneration, there are currently no disease-modifying treatments to delay or prevent degenerative disc disease. This review presents an overview of our current understanding of the developmental processes that regulate intervertebral disc formation, with particular emphasis on the role of the notochord and notochord-derived cells in disc homeostasis and how their loss can result in degeneration. We then describe the role of small animal models in understanding the development of the disc and their use to interrogate disc degeneration and associated pathologies. Finally, we highlight essential development pathways that are associated with disc degeneration and/or implicated in the reparative response of the tissue that might serve as targets for future therapeutic approaches. PMID:27252900

  2. Notochord Cells in Intervertebral Disc Development and Degeneration

    Directory of Open Access Journals (Sweden)

    Matthew R. McCann

    2016-01-01

    Full Text Available The intervertebral disc is a complex structure responsible for flexibility, multi-axial motion, and load transmission throughout the spine. Importantly, degeneration of the intervertebral disc is thought to be an initiating factor for back pain. Due to a lack of understanding of the pathways that govern disc degeneration, there are currently no disease-modifying treatments to delay or prevent degenerative disc disease. This review presents an overview of our current understanding of the developmental processes that regulate intervertebral disc formation, with particular emphasis on the role of the notochord and notochord-derived cells in disc homeostasis and how their loss can result in degeneration. We then describe the role of small animal models in understanding the development of the disc and their use to interrogate disc degeneration and associated pathologies. Finally, we highlight essential development pathways that are associated with disc degeneration and/or implicated in the reparative response of the tissue that might serve as targets for future therapeutic approaches.

  3. Ultrastructure of inclusion bodies in annulus cells in the degenerating human intervertebral disc.

    Science.gov (United States)

    Gruber, H E; Hanley, E N

    2009-06-01

    The rough endoplasmic reticulum (rER) of the cell has an architectural editing function that checks whether protein structure and three-dimensional assembly have occurred properly prior to export of newly synthesized material out of the cell. If these have been faulty, the material is retained within the rER as an inclusion body. Inclusion bodies have been identified previously in chondrocytes and osteoblasts in chondrodysplasias and osteogenesis imperfecta. Inclusion bodies in intervertebral disc cells, however, have only recently been recognized. Our objectives were to use transmission electron microscopy to analyze more fully inclusion bodies in the annulus pulposus and to study the extracellular matrix (ECM) surrounding cells containing inclusion bodies. ECM frequently encapsulated cells with inclusion bodies, and commonly contained prominent banded aggregates of Type VI collagen. Inclusion body material had several morphologies, including relatively smooth, homogeneous material, or a rougher, less homogeneous feature. Such findings expand our knowledge of the fine structure of the human disc cell and ECM during disc degeneration, and indicate the potential utility of ultrastructural identification of discs with intracellular inclusion bodies as a screening method for molecular studies directed toward identification of defective gene products in degenerating discs.

  4. CT morphometry of adult thoracic intervertebral discs.

    Science.gov (United States)

    Fletcher, Justin G R; Stringer, Mark D; Briggs, Christopher A; Davies, Tilman M; Woodley, Stephanie J

    2015-10-01

    Despite being commonly affected by degenerative disorders, there are few data on normal thoracic intervertebral disc dimensions. A morphometric analysis of adult thoracic intervertebral discs was, therefore, undertaken. Archival computed tomography scans of 128 recently deceased individuals (70 males, 58 females, 20-79 years) with no known spinal pathology were analysed to determine thoracic disc morphometry and variations with disc level, sex and age. Reliability was assessed by intraclass correlation coefficients (ICCs). Anterior and posterior intervertebral disc heights and axial dimensions were significantly greater in men (anterior disc height 4.0±1.4 vs 3.6±1.3 mm; posterior disc height 3.6±0.90 vs 3.4±0.93 mm; p<0.01). Disc heights and axial dimensions at T4-5 were similar or smaller than at T2-3, but thereafter increased caudally (mean anterior disc height T4-5 and T10-11, 2.7±0.7 and 5.4±1.2 mm, respectively, in men; 2.6±0.8 and 5.1±1.3 mm, respectively, in women; p<0.05). Except at T2-3, anterior disc height decreased with advancing age and anteroposterior and transverse disc dimensions increased; posterior and middle disc heights and indices of disc shape showed no consistent statistically significant changes. Most parameters showed substantial to almost perfect agreement for intra- and inter-rater reliability. Thoracic disc morphometry varies significantly and consistently with disc level, sex and age. This study provides unique reference data on adult thoracic intervertebral disc morphometry, which may be useful when interpreting pathological changes and for future biomechanical and functional studies.

  5. Current evidence of percutaneous nucleoplasty for the cervical herniated disk: a systematic review.

    Science.gov (United States)

    Wullems, Jorgen A; Halim, Willy; van der Weegen, Walter

    2014-07-01

    Although percutaneous cervical nucleoplasty (PCN) has been shown to be both safe and effective, its application is still debated. PCN applied in disk herniation has not been systematically reviewed before, resulting in a limited insight into its effectiveness and safety, and the quality of available evidence. Therefore, we systematically reviewed the evidence on the efficacy and safety of PCN in patients with a (contained) herniated disk. MEDLINE, EMBASE, and the Cochrane Library (Central Register of Controlled Trials) were searched for randomized controlled trials (RCTs) and nonrandomized studies using the following keywords: "Nucleoplasty," "Cervical," "Hernia," "Herniation," "Prolapse," "Protrusion," "Intervertebral disk," and "Percutaneous disk decompression." First, all articles were appraised for methodological quality, and then, RCTs were graded for the level of evidence according a best-evidence synthesis, because a meta-analysis was not possible. Finally, the RCTs' applicability and clinical relevance also was assessed. Of 75 identified abstracts, 10 full-text articles were included (3 RCTs and 7 nonrandomized studies). These studies represented a total of 1021 patients: 823 patients (≥ 892 disks) were treated by PCN. All studies showed low methodological quality, except for two. The level of evidence of the RCTs was graded as moderate, with low to moderate applicability and clinical relevance. All included studies showed PCN to be an effective and safe procedure in the treatment of (contained) herniated disks at short-, mid-, and long-term follow-up. However, the level of evidence is moderate and shows only low to moderate applicability and clinical relevance. © 2013 World Institute of Pain.

  6. Effect of Degeneration on Fluid–Solid Interaction within Intervertebral Disk Under Cyclic Loading – A Meta-Model Analysis of Finite Element Simulations

    Science.gov (United States)

    Nikkhoo, Mohammad; Khalaf, Kinda; Kuo, Ya-Wen; Hsu, Yu-Chun; Haghpanahi, Mohammad; Parnianpour, Mohamad; Wang, Jaw-Lin

    2015-01-01

    The risk of low back pain resulted from cyclic loadings is greater than that resulted from prolonged static postures. Disk degeneration results in degradation of disk solid structures and decrease of water contents, which is caused by activation of matrix digestive enzymes. The mechanical responses resulted from internal solid–fluid interactions of degenerative disks to cyclic loadings are not well studied yet. The fluid–solid interactions in disks can be evaluated by mathematical models, especially the poroelastic finite element (FE) models. We developed a robust disk poroelastic FE model to analyze the effect of degeneration on solid–fluid interactions within disk subjected to cyclic loadings at different loading frequencies. A backward analysis combined with in vitro experiments was used to find the elastic modulus and hydraulic permeability of intact and enzyme-induced degenerated porcine disks. The results showed that the averaged peak-to-peak disk deformations during the in vitro cyclic tests were well fitted with limited FE simulations and a quadratic response surface regression for both disk groups. The results showed that higher loading frequency increased the intradiscal pressure, decreased the total fluid loss, and slightly increased the maximum axial stress within solid matrix. Enzyme-induced degeneration decreased the intradiscal pressure and total fluid loss, and barely changed the maximum axial stress within solid matrix. The increase of intradiscal pressure and total fluid loss with loading frequency was less sensitive after the frequency elevated to 0.1 Hz for the enzyme-induced degenerated disk. Based on this study, it is found that enzyme-induced degeneration decreases energy attenuation capability of disk, but less change the strength of disk. PMID:25674562

  7. Poroelastic behaviour of the degenerating human intervertebral disc: a ten-day study in a loaded disc culture system

    Directory of Open Access Journals (Sweden)

    KS Emanuel

    2015-06-01

    Full Text Available The intervertebral disc (IVD allows flexibility to the vertebral column, and transfers the predominant axial loads during daily activities. Its axial biomechanical behaviour is poroelastic, due to the water-binding and releasing capacity of the nucleus pulposus. Degeneration of the intervertebral disc presumably affects both the instantaneous elastic response to the load on the IVD and the subsequent interstitial flow of fluid. This study aims to quantify the poroelastic behaviour of the IVD and its change with degeneration, as defined by the magnetic resonance imaging-based Pfirrmann Score (PS. For a period of ten days, 36 human lumbar IVDs were loaded with a simulated physiological axial loading regime, while deformation was monitored. The IVDs responded to the loads with instantaneous elastic and slow poroelastic axial deformation. Several mechanical parameters changed throughout the first five days of the experiment, until the IVDs settled into a dynamic equilibrium. In this equilibrium, degeneration was significantly related to a decrease in disc height loss during the daytime high load phase (ρ = -0.49, and to a decrease in the rate of this deformation during the final half hour of each day (ρ = -0.53. These properties were related to the nucleus glycosaminoglycan/hydroxyproline (GAG/HYP ratio, rather than GAG content alone, indicating that remodelling of the extracellular matrix reduces poroelastic properties of the IVD. This implies that the degenerated discs have a reduced capacity to bind water and/or a reduced resistance against fluid flow. The resulting loss in hydrostatic pressure may further change cell behaviour in the nucleus pulposus.

  8. Aging and degeneration of the intervertebral disc: review of basic science

    Directory of Open Access Journals (Sweden)

    Josemberg da Silva Baptista

    2015-06-01

    Full Text Available Currently there is a growing interest in the study of intervertebral discs due to loss of manpower brought to society by low back and neck pains. These papers seek to delineate the difference between normal aging and disc degeneration, trying to understand what factor would be determining for the second condition. Thus, the morphology field was expanded and knowledge on the structure of intervertebral discs currently uses the research field of cell and molecular biology, and genetics. The results indicate that regardless of age or condition, the intervertebral disc undergoes long and extensive remodeling of its constituents, which are influenced by several factors: environmental, soluble, cell growth and extracellular matrix. In this literature review we describe the biological characteristics of the cervical and lumbar intervertebral disc with a focus on basic science of aging and degeneration, selecting the latest findings and discussions of the area, which influence future research and clinical thoughts.

  9. Fas ligand exists on intervertebral disc cells: a potential molecular mechanism for immune privilege of the disc.

    Science.gov (United States)

    Takada, Toru; Nishida, Kotaro; Doita, Minoru; Kurosaka, Masahiro

    2002-07-15

    Rat and human intervertebral disc specimens were examined immunohistochemically. Reverse transcription polymerase chain reaction (RT-PCR) analysis was also performed on rat disc tissue to demonstrate the existence of Fas ligand. To clarify the existence of Fas ligand on intact intervertebral disc cells. The nucleus pulposus has been reported to be an immune-privileged site. The immune-privileged characteristic in other tissues such as the retina and testis has been attributed to the local expression of Fas ligand, which acts by inducing apoptosis of invading Fas-positive T-cells. The existence of Fas ligand in normal disc cells has not yet been addressed. Skeletally mature SD male rats were killed, and the coccygeal discs were harvested. Human disc specimens were obtained from idiopathic scoliosis patients during surgical procedures. Immunohistochemical staining for Fas ligand was performed for cross-sections of the discs by standard procedures. Reverse transcription polymerase chain reaction analysis was also carried out to demonstrate Fas ligand mRNA expression on rat intervertebral discs. Testes of the rats were used for positive controls, and muscles were used for negative controls. The sections were observed by light microscopy. The nucleus pulposus cells exhibited intense positive immune staining for Fas ligand. The outer anulus fibrosus cells and notochordal cells exhibited little immunopositivity. The positive controls exhibited positive immune staining, and the negative control showed no immunopositivity. The result of RT-PCR confirmed the existence of Fas ligand in disc cells. The human nucleus pulposus cells showed a similar predilection to rat disc cells. We demonstrated the existence of Fas ligand on disc cells, which should play a key role in the potential molecular mechanism to maintain immune privilege of the disc. Immune privilege and Fas ligand expression of the intervertebral disc may provide a new insight for basic science research as well as

  10. Gene expression profile identifies potential biomarkers for human intervertebral disc degeneration.

    Science.gov (United States)

    Guo, Wei; Zhang, Bin; Li, Yan; Duan, Hui-Quan; Sun, Chao; Xu, Yun-Qiang; Feng, Shi-Qing

    2017-12-01

    The present study aimed to reveal the potential genes associated with the pathogenesis of intervertebral disc degeneration (IDD) by analyzing microarray data using bioinformatics. Gene expression profiles of two regions of the intervertebral disc were compared between patients with IDD and controls. GSE70362 containing two groups of gene expression profiles, 16 nucleus pulposus (NP) samples from patients with IDD and 8 from controls, and 16 annulus fibrosus (AF) samples from patients with IDD and 8 from controls, was downloaded from the Gene Expression Omnibus database. A total of 93 and 114 differentially expressed genes (DEGs) were identified in NP and AF samples, respectively, using a limma software package for the R programming environment. Gene Ontology (GO) function enrichment analysis was performed to identify the associated biological functions of DEGs in IDD, which indicated that the DEGs may be involved in various processes, including cell adhesion, biological adhesion and extracellular matrix organization. Pathway enrichment analysis using the Kyoto Encyclopedia of Genes and Genomes (KEGG) demonstrated that the identified DEGs were potentially involved in focal adhesion and the p53 signaling pathway. Further analysis revealed that there were 35 common DEGs observed between the two regions (NP and AF), which may be further regulated by 6 clusters of microRNAs (miRNAs) retrieved with WebGestalt. The genes in the DEG‑miRNA regulatory network were annotated using GO function and KEGG pathway enrichment analysis, among which extracellular matrix organization was the most significant disrupted biological process and focal adhesion was the most significant dysregulated pathway. In addition, the result of protein‑protein interaction network modules demonstrated the involvement of inflammatory cytokine interferon signaling in IDD. These findings may not only advance the understanding of the pathogenesis of IDD, but also identify novel potential

  11. Magnetic resonance imaging of diseased cervical and lumbar intervertebral discs

    Energy Technology Data Exchange (ETDEWEB)

    Kadoya, Satoru; Nakamura, Tsutomu; Takarada, Akira; Yamamoto, Itaru; Sato, Shuji.

    1989-02-01

    Magnetic resonance images (MRI) of diseased cervical and lumbar intervertebral discs involving both intrinsic and extrinsic cord lesions were examined using either a 0.15 T resistive or a 0.5 T superconductive magnetic imaging system. The vertebrae, intervertebral discs, and spinal cord were delineated on spin-echo (SE) images with a long repetition time (TR) and a short echo time (proton density-weighted image). Protrusion of degenerated intervertebral discs into the spinal canal was clearly demonstrated not only on sagittal but also on parasagittal and transverse views. The location of protruded discs and compression of the spinal cord, caudal sac, and nerve roots were well visualized three-dimensionally. Pathological features of intervertebral discs were well appreciated on T/sub 2/-weighted images with long TR and SE pulse sequences. Degeneration of intervertebral discs resulted in decreased signal intensity in cases of lumbar disc involvement. For suspected myelomalacia, the intrinsic cord lesion resulting from traumatic disc protrusion appeared as focal low signal intensity on T/sub 1/-weithed images and as somewhat high intensity on T/sub 2/ weighted images. The inversion recovery sequence with median inversion time displayed an inferior image of low contrast and was judged uninformative in comparison to SE imags. The findings showed MRI to be an essential diagnostic technique for spinal cord disorders. It clearly pinpoints the anatomic structures of the spine and the features of disc degeneration. Both extrinsic and intrinsic cord abnormalities can be identified with MRI. The selection of proper pulse sequences is required for the differentiation of the object of interest. (Namekawa, K).

  12. Magnetic resonance imaging of diseased cervical and lumbar intervertebral discs

    International Nuclear Information System (INIS)

    Kadoya, Satoru; Nakamura, Tsutomu; Takarada, Akira; Yamamoto, Itaru; Sato, Shuji.

    1989-01-01

    Magnetic resonance images (MRI) of diseased cervical and lumbar intervertebral discs involving both intrinsic and extrinsic cord lesions were examined using either a 0.15 T resistive or a 0.5 T superconductive magnetic imaging system. The vertebrae, intervertebral discs, and spinal cord were delineated on spin-echo (SE) images with a long repetition time (TR) and a short echo time (proton density-weighted image). Protrusion of degenerated intervertebral discs into the spinal canal was clearly demonstrated not only on sagittal but also on parasagittal and transverse views. The location of protruded discs and compression of the spinal cord, caudal sac, and nerve roots were well visualized three-dimensionally. Pathological features of intervertebral discs were well appreciated on T 2 -weighted images with long TR and SE pulse sequences. Degeneration of intervertebral discs resulted in decreased signal intensity in cases of lumbar disc involvement. For suspected myelomalacia, the intrinsic cord lesion resulting from traumatic disc protrusion appeared as focal low signal intensity on T 1 -weithed images and as somewhat high intensity on T 2 weighted images. The inversion recovery sequence with median inversion time displayed an inferior image of low contrast and was judged uninformative in comparison to SE imags. The findings showed MRI to be an essential diagnostic technique for spinal cord disorders. It clearly pinpoints the anatomic structures of the spine and the features of disc degeneration. Both extrinsic and intrinsic cord abnormalities can be identified with MRI. The selection of proper pulse sequences is required for the differentiation of the object of interest. (Namekawa, K)

  13. Discussion on the method to increase the successful rate of L5/S1 intervertebral disc puncture

    International Nuclear Information System (INIS)

    Zhong Xianyi; Li Liangjun; Yu Chengxin

    2007-01-01

    Objective: To study the effective methods of L 5 /S 1 intervertebral disc puncture without drilling to solve the barriers from iliaca. Methods: (1) puncturing with belly-buttock sticking out: to enlarge waist sacro-iliaca angle to move the puncture point up; (2) puncturing through intervertebral edge: puncturing through L 5 to 1/3 intervertebral disc to make the puncture point move Up; (3) puncturing through L 5 /S 1 intervertebral disc with the self-made puncture location instrument. Results with the methods, 280 cases with L 5 /S 1 intervertebral disc protrusion have been successfully punctured, with successful rate 100%. Conclusion: These methods are ideal and easy to use to treat L 5 /S 1 intervertebral disc protrusion puncture, and worth popularizing. (authors)

  14. Computerized tomography in the diagnosis of degenerative vertebral diseases

    International Nuclear Information System (INIS)

    Bokarev, V.S.; Savchenko, A.P.; Ternovoj, S.K.

    1989-01-01

    CT and roentgenography were used for the investigation of 78 patients with the radicular syndrome. The state of the intervertebral disks, intervertebral joints and cerebrospinal canal in degenerative vertebral diseases was assessed. CT permits the detection of hernia, protrusion of the intervertebral disks, deformity of the intervertebral joints, and the narrowing of the cerebrospinal canal as a result of degenerative changes, as well as establishing the cause of the affection of neural structures in the cerebrospinal canal, radicular holes. CT possesses some advantages over roentgenography in the diagnosis of degenerative vertebral diseases

  15. Replacing the nucleus pulposus of the intervertebral disk: prediction of suitable properties of a replacement material using finite element analysis.

    Science.gov (United States)

    Meakin, J R

    2001-03-01

    An axisymmetric finite element model of a human lumbar disk was developed to investigate the properties required of an implant to replace the nucleus pulposus. In the intact disk, the nucleus was modeled as a fluid, and the annulus as an elastic solid. The Young's modulus of the annulus was determined empirically by matching model predictions to experimental results. The model was checked for sensitivity to the input parameter values and found to give reasonable behavior. The model predicted that removal of the nucleus would change the response of the annulus to compression. This prediction was consistent with experimental results, thus validating the model. Implants to fill the cavity produced by nucleus removal were modeled as elastic solids. The Poisson's ratio was fixed at 0.49, and the Young's modulus was varied from 0.5 to 100 MPa. Two sizes of implant were considered: full size (filling the cavity) and small size (smaller than the cavity). The model predicted that a full size implant would reverse the changes to annulus behavior, but a smaller implant would not. By comparing the stress distribution in the annulus, the ideal Young's modulus was predicted to be approximately 3 MPa. These predictions have implications for current nucleus implant designs. Copyright 2001 Kluwer Academic Publishers

  16. A role for TNFα in intervertebral disc degeneration: A non-recoverable catabolic shift

    International Nuclear Information System (INIS)

    Purmessur, D.; Walter, B.A.; Roughley, P.J.; Laudier, D.M.; Hecht, A.C.; Iatridis, James

    2013-01-01

    Highlights: ► TNFα induced catabolic changes similar to human intervertebral disc degeneration. ► The metabolic shift induced by TNFα was sustained following removal. ► TNFα induced changes suggestive of cell senescence without affecting cell viability. ► Interventions are required to stimulate anabolism and increase cell proliferation. -- Abstract: This study examines the effect of TNFα on whole bovine intervertebral discs in organ culture and its association with changes characteristic of intervertebral disc degeneration (IDD) in order to inform future treatments to mitigate the chronic inflammatory state commonly found with painful IDD. Pro-inflammatory cytokines such as TNFα contribute to disc pathology and are implicated in the catabolic phenotype associated with painful IDD. Whole bovine discs were cultured to examine cellular (anabolic/catabolic gene expression, cell viability and senescence using β-galactosidase) and structural (histology and aggrecan degradation) changes in response to TNFα treatment. Control or TNFα cultures were assessed at 7 and 21 days; the 21 day group also included a recovery group with 7 days TNFα followed by 14 days in basal media. TNFα induced catabolic and anti-anabolic shifts in the nucleus pulposus (NP) and annulus fibrosus (AF) at 7 days and this persisted until 21 days however cell viability was not affected. Data indicates that TNFα increased aggrecan degradation products and suggests increased β-galactosidase staining at 21 days without any recovery. TNFα treatment of whole bovine discs for 7 days induced changes similar to the degeneration processes that occur in human IDD: aggrecan degradation, increased catabolism, pro-inflammatory cytokines and nerve growth factor expression. TNFα significantly reduced anabolism in cultured IVDs and a possible mechanism may be associated with cell senescence. Results therefore suggest that successful treatments must promote anabolism and cell proliferation in

  17. Assessment of Intervertebral Disc Degeneration With Magnetic Resonance Single-Voxel Spectroscopy

    Science.gov (United States)

    Zuo, Jin; Saadat, Ehsan; Romero, Adan; Loo, Kimberly; Li, Xiaojuan; Link, Thomas M.; Kurhanewicz, John; Majumdar, Sharmila

    2014-01-01

    This study examined the feasibility of using short-echo water-suppressed point-resolved spectroscopy (PRESS) on a clinical 3T magnetic resonance (MR) scanner for evaluating biochemical changes in degenerated bovine and cadaveric human inter-vertebral discs. In bovine discs (N = 17), degeneration was induced with papain injections. Degeneration of human cadaveric discs (N = 27) was assessed using the Pfirrmann grading on T2-weighted images. Chemicals in the carbohydrate region (Carb), the choline head group (Cho), the N-acetyl region (N-acetyl), and the lipid and lactate region (Lac+Lip) were quantified using 1H PRESS, and were compared between specimens with different degrees of degeneration. The correlation between the spectroscopic findings and glycosaminoglycan (GAG) quantification using biochemical assays was determined. Significant differences were found between the ratios (N-acetyl/Cho, N-acetyl/Lac+Lip) acquired before and after papain injection in bovine discs. For human cadaveric discs, significant differences in the ratios (N-acetyl/Carb, N-acetyl/Lac+Lip) were found between discs having high and low Pfirrmann scores. Significant correlations were found between N-acetyl/Lac+Lip and GAG content in bovine discs (R = 0.77, P = 0.0007) and cadaveric discs (R = 0.83, P < 0.0001). Significant correlation between N-acetyl/Cho and GAG content was also found in cadaver discs (R = 0.64, P = 0.0039). This study demonstrates for the first time that short-echo PRESS on a clinical 3T MR scanner can be used to noninvasively and can reproducibly quantify metabolic changes associated with degeneration of intervertebral discs. PMID:19780173

  18. Dysregulated miR-127-5p contributes to type II collagen degradation by targeting matrix metalloproteinase-13 in human intervertebral disc degeneration.

    Science.gov (United States)

    Hua, Wen-Bin; Wu, Xing-Huo; Zhang, Yu-Kun; Song, Yu; Tu, Ji; Kang, Liang; Zhao, Kang-Cheng; Li, Shuai; Wang, Kun; Liu, Wei; Shao, Zeng-Wu; Yang, Shu-Hua; Yang, Cao

    2017-08-01

    Intervertebral disc degeneration (IDD) is a chronic disease associated with the degradation of extracellular matrix (ECM). Matrix metalloproteinase (MMP)-13 is a major enzyme that mediates the degradation of ECM components. MMP-13 has been predicted to be a potential target of miR-127-5p. However, the exact function of miR-127-5p in IDD is still unclear. We designed this study to evaluate the correlation between miR-127-5p level and the degeneration of human intervertebral discs and explore the potential mechanisms. miR-127-5p levels and MMP-13 mRNA levels were detected by quantitative real-time polymerase chain reaction (qPCR). To determine whether MMP-13 is a target of miR-127-5p, dual luciferase reporter assays were performed. miR-127-5p mimic and miR-127-5p inhibitor were used to overexpress or downregulate miR-127-5p expression in human NP cells, respectively. Small interfering RNA (siRNA) was used to knock down MMP-13 expression in human NP cells. Type II collagen expression in human NP cells was detected by qPCR, western blotting, and immunofluorescence staining. We confirmed that miR-127-5p was significantly downregulated in nucleus pulposus (NP) tissue of degenerative discs and its expression was inversely correlated with MMP-13 mRNA levels. We reveal that MMP-13 may act as a target of miR-127-5p. Expression of miR-127-5p was inversely correlated with type II collagen expression in human NP cells. Moreover, suppression of MMP-13 expression by siRNA blocked downstream signaling and increased type II collagen expression. Dysregulated miR-127-5p contributed to the degradation of type II collagen by targeting MMP-13 in human IDD. Our findings highlight that miR-127-5p may serve as a new therapeutic target in IDD. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  19. CT Fluoroscopy-Guided Transsacral Intervertebral Drainage for Pyogenic Spondylodiscitis at the Lumbosacral Junction

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Tomohiro, E-mail: t-matsu@tokai-u.jp; Mine, Takahiko, E-mail: mine@tsc.u-tokai.ac.jp; Hayashi, Toshihiko, E-mail: t.hayashi@tokai.ac.jp [Tokai University School of Medicine, Department of Radiology, Tokai University Hachioji Hospital (Japan); Kamono, Masahiro, E-mail: kamono@tsc.u-tokai.ac.jp; Taoda, Akiko, E-mail: acco@is.icc.u-tokai.ac.jp; Higaki, Megumu, E-mail: higaki@hachioji-hosp.tokai.ac.jp [Tokai University School of Medicine, Department of General Internal Medicine, Tokai University Hachioji Hospital (Japan); Hasebe, Terumitsu, E-mail: hasebe@tokai-u.jp [Tokai University School of Medicine, Department of Radiology, Tokai University Hachioji Hospital (Japan)

    2017-01-15

    PurposeTo retrospectively describe the feasibility and efficacy of CT fluoroscopy-guided transsacral intervertebral drainage for pyogenic spondylodiscitis at the lumbosacral junction with a combination of two interventional radiological techniques—CT-guided bone biopsy and abscess drainage.Materials and methodsThree patients with pyogenic spondylodiscitis at the lumbosacral junction were enrolled in this study between July 2013 and December 2015. The procedure of CT fluoroscopy-guided transsacral intervertebral drainage for pyogenic spondylodiscitis at the lumbosacral junction was as follows: the sacrum at S1 pedicle was penetrated with an 11-gauge (G) bone biopsy needle to create a path for an 8-French (F) pigtail drainage catheter. The bone biopsy needle was withdrawn, and an 18-G needle was inserted into the intervertebral space of the lumbosacral junction. Then, a 0.038-inch guidewire was inserted into the intervertebral space. Finally, the 8-F pigtail drainage catheter was inserted over the guidewire until its tip reached the intervertebral space. All patients received six-week antibiotics treatment.ResultsSuccessful placement of the drainage catheter was achieved for each patient without procedural complications. The duration of drainage was 17–33 days. For two patients, specific organisms were isolated; thus, definitive medical therapy was possible. All patients responded well to the treatment.ConclusionsCT fluoroscopy-guided transsacral intervertebral drainage for pyogenic spondylodiscitis at the lumbosacral junction is feasible and can be effective with a combination of two interventional techniques—CT fluoroscopy-guided bone biopsy and abscess drainage.

  20. Passive Stretch Versus Active Stretch on Intervertebral Movement in Non - Specific Neck Pain

    International Nuclear Information System (INIS)

    Abd El - Aziz, A.H.; Amin, D.I.; Moustafa, I.

    2016-01-01

    Neck pain is one of the most common and painful musculoskeletal conditions. Point prevalence ranges from 6% to 22% and up to 38% of the elderly population, while lifetime prevalence ranges from 14,2% to 71%. Up till now no randomized study showed the effect between controversy of active and passive stretch on intervertebral movement. The purpose: the current study was to investigate the effect of the passive and active stretch on intervertebral movement in non - specific neck pain. Material and methods: Forty five subjects from both sexes with age range between 18 and 30 years and assigned in three groups, group I (15) received active stretch, ultrasound and TENS. Group II (15) received passive stretch, ultrasound and TENS. Group III (15) received ultrasound and TENS. The radiological assessment was used to measure rotational and translational movement of intervertebral movement before and after treatment. Results: MANOVA test was used for radiological assessment before and after treatment there was significant increase in intervertebral movement in group I as p value =0.0001. Conclusion: active stretch had a effect in increasing the intervertebral movement compared to the passive stretch

  1. Acute pyogenic discitis in a degenerative intervertebral disc in an adult

    Directory of Open Access Journals (Sweden)

    Masamitsu Tanaka

    2010-08-01

    Full Text Available Masamitsu Tanaka1,2, Hiroshi Shimizu2, Yoshiyuki Yato1, Takashi Asazuma1, Koichi Nemoto11Department of Orthopedic Surgery, National Defense Medical College, Tokorozawa, Saitama; 2Department of Orthopedic Surgery, Self Defense Force Fukuoka Hospital, Kasuga, Fukuoka, JapanAbstract: A 35-year-old male who had been receiving conservative treatment for L4 isthmic spondylolisthesis suffered from pyogenic spondylodiscitis in the degenerative L4/L5 intervertebral disc space, which could be identified by comparison with previous images. Symptoms improved with conservative antibiotic treatment. Neovascularization may occur in the annulus fibrosus of a degenerative intervertebral disc, which may increase the risk of hematogenous infection, leading to “discitis” even in adults.Keywords: spondylodiscitis, spondylitis, discitis, isthmic spondylolisthesis, spondylolysis, intervertebral disc degeneration

  2. Intervertebral Fusion with Mobile Microendoscopic Discectomy for Lumbar Degenerative Disc Disease.

    Science.gov (United States)

    Xu, Bao-Shan; Liu, Yue; Xu, Hai-Wei; Yang, Qiang; Ma, Xin-Long; Hu, Yong-Cheng

    2016-05-01

    The aim of this article is to introduce a technique for lumbar intervertebral fusion that incorporates mobile microendoscopic discectomy (MMED) for lumbar degenerative disc disease. Minimally invasive transforaminal lumbar interbody fusion is frequently performed to treat degenerative diseases of the lumbar spine; however, the scope of such surgery and vision is limited by what the naked eye can see through the expanding channel system. To expand the visual scope and reduce trauma, we perform lumbar intervertebral fusion with the aid of a MMED system that provides a wide field through freely tilting the surgical instrument and canals. We believe that this technique is a good option for treating lumbar degenerative disc disease that requires lumbar intervertebral fusion. © 2016 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

  3. Parametric modeling of the intervertebral disc space in 3D: application to CT images of the lumbar spine.

    Science.gov (United States)

    Korez, Robert; Likar, Boštjan; Pernuš, Franjo; Vrtovec, Tomaž

    2014-10-01

    Gradual degeneration of intervertebral discs of the lumbar spine is one of the most common causes of low back pain. Although conservative treatment for low back pain may provide relief to most individuals, surgical intervention may be required for individuals with significant continuing symptoms, which is usually performed by replacing the degenerated intervertebral disc with an artificial implant. For designing implants with good bone contact and continuous force distribution, the morphology of the intervertebral disc space and vertebral body endplates is of considerable importance. In this study, we propose a method for parametric modeling of the intervertebral disc space in three dimensions (3D) and show its application to computed tomography (CT) images of the lumbar spine. The initial 3D model of the intervertebral disc space is generated according to the superquadric approach and therefore represented by a truncated elliptical cone, which is initialized by parameters obtained from 3D models of adjacent vertebral bodies. In an optimization procedure, the 3D model of the intervertebral disc space is incrementally deformed by adding parameters that provide a more detailed morphometric description of the observed shape, and aligned to the observed intervertebral disc space in the 3D image. By applying the proposed method to CT images of 20 lumbar spines, the shape and pose of each of the 100 intervertebral disc spaces were represented by a 3D parametric model. The resulting mean (±standard deviation) accuracy of modeling was 1.06±0.98mm in terms of radial Euclidean distance against manually defined ground truth points, with the corresponding success rate of 93% (i.e. 93 out of 100 intervertebral disc spaces were modeled successfully). As the resulting 3D models provide a description of the shape of intervertebral disc spaces in a complete parametric form, morphometric analysis was straightforwardly enabled and allowed the computation of the corresponding

  4. Clinical anatomy and clinical significance of the cervical intervertebral foramen: a review.

    Science.gov (United States)

    Sioutas, G; Kapetanakis, S

    2016-01-01

    The aim of this paper is to summarise the knowledge about the anatomy of the cervical intervertebral foramen as a whole. Such reviews are rare in the literature. The intervertebral or neural foramen is the opening between the spinal canal and the extraspinal region. It is located between the vertebral pedicles at all spinal levels. A number of structures pass through the foramen: nerves, vessels and ligaments. We describe the bony borders and dimensions of the foramen, the adjacent ligaments, the arteries and veins passing through or neighbouring it, and the neural components. Many procedures are performed in the area of the cervical intervertebral foramen. Knowledge of the anatomy of the foramen is essential in order to operate to the area and to minimize iatrogenic injuries.

  5. A method for quantifying intervertebral disc signal intensity on T2-weighted imaging

    International Nuclear Information System (INIS)

    Nagashima, Masaki; Abe, Hitoshi; Amaya, Kenji; Matsumoto, Hideo; Yanaihara, Hisashi; Nishiwaki, Yuji; Toyama, Yoshiaki; Matsumoto, Morio

    2012-01-01

    Background Quantification of intervertebral disc degeneration based on intensity of the nucleus pulposus in magnetic resonance imaging (MRI) often uses the mean intensity of the region of interest (ROI) within the nucleus pulposus. However, the location and size of ROI have varied in different reports, and none of the reported methods can be considered fully objective. Purpose To develop a more objective method of establishing ROIs for quantitative evaluation of signal intensity in the nucleus pulposus using T2-weighted MRI. Material and Methods A 1.5-T scanner was used to obtain T2-weighted mid-sagittal images. A total of 288 intervertebral discs from 48 patients (25 men, 23 women) were analyzed. Mean age was 47.4 years (range, 17-69 years). All discs were classified into five grades according to Pfirrmann et al. Discs in grades I and II were defined as bright discs, and discs in grades IV and V were defined as dark discs. Eight candidate methods of ROI determination were devised. The method offering the highest degree of discrimination between bright and dark discs was investigated among these eight methods. Results The method with the greatest degree of discrimination was as follows. The quadrangle formed by anterior and posterior edges of the upper and lower end plates in contact with the intervertebral disc to be measured was defined as the intervertebral area. A shape similar to the intervertebral area but with one-quarter the area was drawn. The geometrical center of the shape was matched to the center of intensity, and this shape was then used as the ROI. Satisfactory validity and reproducibility were obtained using this method. Conclusion The present method offers adequate discrimination and could be useful for longitudinal tracking of intervertebral disc degeneration with sufficient reproducibility

  6. A method for quantifying intervertebral disc signal intensity on T2-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nagashima, Masaki [Dept. of Orthopaedic Surgery, Keio Univ. School of Medicine, Tokyo (Japan); Dept. of Orthopaedic Surgery, Kitasato Univ. Kitasato Inst. Hospital, Tokyo (Japan); Abe, Hitoshi [Dept. of Orthopaedic Surgery, Kitasato Univ. Kitasato Inst. Hospital, Tokyo (Japan)], E-mail: hit-abe@insti.kitasato-u.ac.jp; Amaya, Kenji [Graduate School of Information Science and Engineering, Tokyo Inst. of Technology, Tokyo (Japan); Matsumoto, Hideo [Inst. for Integrated Sports Medicine, Keio Univ. School of Medicine, Tokyo (Japan); Yanaihara, Hisashi [Dept. of Diagnostic Radiology, Kitasato Univ. Kitasato Inst. Hospital, Tokyo (Japan); Nishiwaki, Yuji [Dept. of Environmental and Occupational Health, Toho Univ. School of Medicine, Tokyo (Japan); Toyama, Yoshiaki; Matsumoto, Morio [Dept. of Orthopaedic Surgery, Keio Univ. School of Medicine, Tokyo (Japan)

    2012-11-15

    Background Quantification of intervertebral disc degeneration based on intensity of the nucleus pulposus in magnetic resonance imaging (MRI) often uses the mean intensity of the region of interest (ROI) within the nucleus pulposus. However, the location and size of ROI have varied in different reports, and none of the reported methods can be considered fully objective. Purpose To develop a more objective method of establishing ROIs for quantitative evaluation of signal intensity in the nucleus pulposus using T2-weighted MRI. Material and Methods A 1.5-T scanner was used to obtain T2-weighted mid-sagittal images. A total of 288 intervertebral discs from 48 patients (25 men, 23 women) were analyzed. Mean age was 47.4 years (range, 17-69 years). All discs were classified into five grades according to Pfirrmann et al. Discs in grades I and II were defined as bright discs, and discs in grades IV and V were defined as dark discs. Eight candidate methods of ROI determination were devised. The method offering the highest degree of discrimination between bright and dark discs was investigated among these eight methods. Results The method with the greatest degree of discrimination was as follows. The quadrangle formed by anterior and posterior edges of the upper and lower end plates in contact with the intervertebral disc to be measured was defined as the intervertebral area. A shape similar to the intervertebral area but with one-quarter the area was drawn. The geometrical center of the shape was matched to the center of intensity, and this shape was then used as the ROI. Satisfactory validity and reproducibility were obtained using this method. Conclusion The present method offers adequate discrimination and could be useful for longitudinal tracking of intervertebral disc degeneration with sufficient reproducibility.

  7. On the modeling of the intervertebral joint in multibody models for the spine

    International Nuclear Information System (INIS)

    Christophy, Miguel; Curtin, Maurice; Faruk Senan, Nur Adila; Lotz, Jeffrey C.; O’Reilly, Oliver M.

    2013-01-01

    The need to develop feasible computational musculoskeletal models of the spine has led to the development of several multibody models. Central features in these works are models for the ligaments, muscles, and intervertebral joint. The purpose of the present paper is to show how experimental measurements of joint stiffnesses can be properly incorporated using a bushing element. The required refinements to existing bushing force functions in musculoskeletal software platforms are discussed and further implemented using a SpineBushing element specific to the intervertebral joint. Four simple lumbar spine models are then used to illustrate the accompanying improvements. Electronic supplemental material for this article includes a complementary review of formulations of stiffness matrices for the intervertebral joint

  8. Influence of degenerative changes of intervertebral disc

    Directory of Open Access Journals (Sweden)

    WANG Yi

    2012-04-01

    Full Text Available 【Abstract】Objective: To investigate the material properties of normal and degenerated intervertebral discs (IVDs and examine the effect of degenerative changes on IVD pathology. Methods: A computer-based online search was under-taken to identify English articles about material properties of IVDs published from January 1950 to 2011 in PubMed database. The retrieved keywords included material properties, intervertebral disc and degeneration. Based on the principles of reliability, advancement and efficiency, the obtained data were primarily examined, and the original source was retrieved to read the full-text. Repetitive articles were excluded. The data of material properties of normal and degenerated IVDs were summarized and analyzed by meta-analysis. Results: The data of Young's modulus, Poisson's ratio, shear modulus, hydraulic permeability and intradiscal pres-sure of normal and degenerated IVDs were obtained. Com-pared with normal IVDs, the Young's modulus and shear modulus of annulus fibrosus and nucleus pulposus were higher in degenerated IVDs, the Poisson's ratio was lower while the hydraulic permeability and intradiscal pressure were higher. Besides, the degeneration-related alterations in IVDs had an influence both on itself and other spinal structures, leading to diseases such as bulging disc, discogenic pain and spinal stenosis. Meanwhile, the heavy mechanical loading and injury indicated important pathways to IVD degeneration. Conclusions: To a certain extent, the degenerative changes of IVD influence its material properties. And the degeneration-related alterations of composition can cause structural failure of IVDs, leading to injuries and diseases. Key words: Intervertebral disc; Mechanical phenomena; Degeneration; Elastic modulus; Permeability; Pathology

  9. Can Exercise Positively Influence the Intervertebral Disc?

    NARCIS (Netherlands)

    Belavý, Daniel L.; Albracht, Kirsten; Bruggemann, Gert Peter; Vergroesen, Pieter Paul A; van Dieën, Jaap H.

    2016-01-01

    To better understand what kinds of sports and exercise could be beneficial for the intervertebral disc (IVD), we performed a review to synthesise the literature on IVD adaptation with loading and exercise. The state of the literature did not permit a systematic review; therefore, we performed a

  10. Intervertebral disc herniation: prevalence and association with ...

    African Journals Online (AJOL)

    Background: Low back pain is one of the common health problems encountered in life with intervertebral disc herniation being a common cause of its occurrence. Magnetic resonance imaging has emerged the gold standard for diagnosing a herniated disc. Aims and Objectives: To assess the frequency and pattern of ...

  11. Formation of the sacrum requires down-regulation of sonic hedgehog signaling in the sacral intervertebral discs.

    Science.gov (United States)

    Bonavita, Raffaella; Vincent, Kathleen; Pinelli, Robert; Dahia, Chitra Lekha

    2018-05-21

    In humans, the sacrum forms an important component of the pelvic arch, and it transfers the weight of the body to the lower limbs. The sacrum is formed by collapse of the intervertebral discs (IVDs) between the five sacral vertebrae during childhood, and their fusion to form a single bone. We show that collapse of the sacral discs in the mouse is associated with the down-regulation of sonic hedgehog (SHH) signaling in the nucleus pulposus (NP) of the disc, and many aspects of this phenotype can be reversed by experimental postnatal activation of HH signaling. We have previously shown that SHH signaling is essential for the normal postnatal growth and differentiation of intervertebral discs elsewhere in the spine, and that loss of SHH signaling leads to pathological disc degeneration, a very common disorder of aging. Thus, loss of SHH is pathological in one region of the spine but part of normal development in another. © 2018. Published by The Company of Biologists Ltd.

  12. Tracing notochord-derived cells using a Noto-cre mouse: implications for intervertebral disc development.

    Science.gov (United States)

    McCann, Matthew R; Tamplin, Owen J; Rossant, Janet; Séguin, Cheryle A

    2012-01-01

    Back pain related to intervertebral disc degeneration is the most common musculoskeletal problem, with a lifetime prevalence of 82%. The lack of effective treatment for this widespread problem is directly related to our limited understanding of disc development, maintenance and degeneration. The aim of this study was to determine the developmental origins of nucleus pulposus cells within the intervertebral disc using a novel notochord-specific Cre mouse. To trace the fate of notochordal cells within the intervertebral disc, we derived a notochord-specific Cre mouse line by targeting the homeobox gene Noto. Expression of this gene is restricted to the node and the posterior notochord during gastrulation [embryonic day 7.5 (E7.5)-E12.5]. The Noto-cre mice were crossed with a conditional lacZ reporter for visualization of notochord fate in whole-mount embryos. We performed lineage-tracing experiments to examine the contribution of the notochord to spinal development from E12.5 through to skeletally mature mice (9 months). Fate mapping studies demonstrated that, following elongation and formation of the primitive axial skeleton, the notochord gives rise to the nucleus pulposus in fully formed intervertebral discs. Cellular localization of β-galactosidase (encoded by lacZ) and cytokeratin-8 demonstrated that both notochordal cells and chondrocyte-like nucleus pulposus cells are derived from the embryonic notochord. These studies establish conclusively that notochordal cells act as embryonic precursors to all cells found within the nucleus pulposus of the mature intervertebral disc. This suggests that notochordal cells might serve as tissue-specific progenitor cells within the disc and establishes the Noto-cre mouse as a unique tool to interrogate the contribution of notochordal cells to both intervertebral disc development and disc degeneration.

  13. Design Concepts of Polycarbonate-Based Intervertebral Lumbar Cages: Finite Element Analysis and Compression Testing

    Directory of Open Access Journals (Sweden)

    J. Obedt Figueroa-Cavazos

    2016-01-01

    Full Text Available This work explores the viability of 3D printed intervertebral lumbar cages based on biocompatible polycarbonate (PC-ISO® material. Several design concepts are proposed for the generation of patient-specific intervertebral lumbar cages. The 3D printed material achieved compressive yield strength of 55 MPa under a specific combination of manufacturing parameters. The literature recommends a reference load of 4,000 N for design of intervertebral lumbar cages. Under compression testing conditions, the proposed design concepts withstand between 7,500 and 10,000 N of load before showing yielding. Although some stress concentration regions were found during analysis, the overall viability of the proposed design concepts was validated.

  14. Aggressive discectomy for single level lumbar disk herniation

    Directory of Open Access Journals (Sweden)

    Md. Kamrul Ahsan

    2017-09-01

    Full Text Available Aggressive open lumbar discectomy is the most commonly performed surgical procedure for patients with persistent low back and leg pain. In this retrospective study,  1,380 patients were evaluated for long-term results of aggressive discectomy for the single level lumbar disk herniation. Demographic data, surgical data, complications and reherniation rate were collected and clinical outcomes were assessed using visual analogue score (VAS, Oswestry disability index (ODI and modified Mcnab criteria. The mean follow-up period was 28.8 months. According to the modified Mcnab criteria, the long-term results were excellent in 640 cases, good in 445 cases, fair in 255 cases, and poor in 40 cases. The mean VAS scores for back and radicular pains and ODI at the end of 2 years were 1.1 ± 1.0, 1.5 ± 0.5 and 6.6 ± 3.1% respectively. The complications were foot drop (n=7, dural tear (n=14, superficial wound infection (n=17, discitis (n=37 and reherniation (n=64. The dural tear and superficial wound infections resolved after treatment but 28 discitis patients were treated by conservatively and the remaining 9 underwent surgery. Among reherniation patients, 58 underwent revision discectomy and 4 underwent transforaminal lumbar interbody fusion and stabilization. Aggressive discectomy is an effective treatment of lumbar disk herniation and maintains a lower incidence of reherniation but leads to a collapse of disc height and in long run gives rise to intervertebral instability and accelerates spondylosis.

  15. MRI-based relationships between spine pathology, intervertebral disc degeneration, and muscle fatty infiltration in chondrodystrophic and non-chondrodystrophic dogs.

    Science.gov (United States)

    Lerer, Assaf; Nykamp, Stephanie G; Harriss, Alexandra B; Gibson, Thomas W G; Koch, Thomas G; Brown, Stephen H M

    2015-11-01

    Human studies have revealed a link between muscle degeneration and low back pain, although the cause and effect of this relationship is not clear. Dogs provide a naturally developing model of intervertebral disc (IVD)-related low back pain that may provide insight into relationships between IVD and muscle degeneration. This study aimed to quantify, via magnetic resonance imaging (MRI), the magnitude and location of fatty infiltration in spine muscles of chondrodystrophic (CD) and non-chondrodystrophic (NCD) dogs suffering from both intervertebral disc herniation (IVDH) and non-disc-related spinal disorders, and relate this to intervertebral disc degeneration (IVDD). This study used retrospective MRI-based analysis of IVDD and muscle fatty infiltration in CD and NCD dogs. A portion of this study was funded ($1,000) by the Pet Trust Fund, Ontario Veterinary College. Magnetic resonance imaging from 180 dogs were separated into four groups: (1) CD with IVDH; (2) CD with non-IVDH spinal pathology; (3) NCD with IVDH; (4) NCD with non-IVDH spinal pathology. For each dog at intervertebral levels T12-T13 to L6-L7, IVDD was subjectively graded and muscle-fat indices (MFIndices) were quantified for multifidus, erector spinae, and psoas muscle groups. Intervertebral disc degeneration grade was higher (ppathology. Muscle-fat indices of multifidus and psoas were higher (ppathology compared with dogs with IVDH. Erector spinae demonstrated higher (ppathology. Dog groups with higher average IVDD grades demonstrated less fatty infiltration within their multifidus and psoas muscles, compared with groups with lower IVDD grades. This finding was consistent across both CD and NCD breeds as well as across dogs presenting with IVDH and those presenting with a non-IVDH spinal pathology. Thus, the presence or severity of IVDD is not uniquely related to fatty infiltration in these muscles, but rather the presence, or possibly severity or chronicity, of general spine pathology is likely a

  16. Relationships between lumbar inter-vertebral motion and lordosis in healthy adult males: a cross sectional cohort study.

    OpenAIRE

    du Rose, A.; Breen, Alan C.

    2016-01-01

    Background Intervertebral motion impairment is widely thought to be related to chronic back disability, however, the movements of inter-vertebral pairs are not independent of each other and motion may also be related to morphology. Furthermore, maximum intervertebral range of motion (IV-RoMmax) is difficult to measure accurately in living subjects. The purpose of this study was to explore possible relationships between (IV-RoMmax) and lordosis, initial attainment rate and IV-RoMmax at other l...

  17. Effect of intervertebral disc disease on scoliosis in the lumbar spine

    Directory of Open Access Journals (Sweden)

    Wojcik Gustaw

    2014-09-01

    Full Text Available Lumbar intervertebral discopathy is a common clinical problem and a significant cause of low back pain. Usually it is associated with overload and damage to the intervertebral disc, which directly relates to the instability of the motion segment. Renal normal anatomy between tissues within the spinal canal is a cause of the reflex curvature of the spine, the goal is to increase the volume of the spinal channel and reduce the compression of the nerve tissue. Knee-jerk reaction to pain is an non physiological change of the setting of the spine in the frontal plane.

  18. Effects of Lead Intoxication on Intervertebral Disc (Experimental Study

    Directory of Open Access Journals (Sweden)

    V.Ye. Maltseva

    2012-02-01

    Full Text Available The article presents the results of experimental study of the effectы of lead intoxication on the intervertebral disc of laboratory rats. It was revealed that in lead intoxication degenerative disorders occur in all parts of the intervertebral disc of rats, affecting both the structure of the annulus fibrosus and the nucleus pulposus. At the same time degenerative changes of the annulus fibrosus can be expressed in disturbance of foliation, due to the appearance of cracks in plates and between them, banding of collagen fibers, reducing the density of fibrochondrocytes. In the nucleus pulposus fragmentation of syncytium structure occurs as well as disturbance of the interconnection between notochordal cells.

  19. Magnetic resonance imaging of canine degenerative lumbar spine diseases

    International Nuclear Information System (INIS)

    Karkkainen, M.; Punto, L.U.; Tulamo, R.M.

    1993-01-01

    Degenerative lumbar spine diseases, i.e., sacrolumbar stenosis, intervertebral disk degeneration and protrusion and spondylosis deformans of the canine lumbar spine were studied in eleven canine patients and three healthy controls using radiography and 0.02 T and 0.04 T low field magnetic resonance imaging. The T1 and T2 weighted images were obtained in sagittal and transverse planes. The loss of hydration of nucleus pulposus, taken as a sign of degeneration in the intervertebral disks, could be evaluated in both T1 and T2 weighted images. As a noninvasive method magnetic resonance imaging gave more exact information about the condition of intervertebral disks than did radiography. Sacrolumbar stenosis and compression of the spinal cord or cauda equina and surrounding tissue could be evaluated without contrast medium

  20. Senescent intervertebral disc cells exhibit perturbed matrix homeostasis phenotype.

    Science.gov (United States)

    Ngo, Kevin; Patil, Prashanti; McGowan, Sara J; Niedernhofer, Laura J; Robbins, Paul D; Kang, James; Sowa, Gwendolyn; Vo, Nam

    2017-09-01

    Aging greatly increases the risk for intervertebral disc degeneration (IDD) as a result of proteoglycan loss due to reduced synthesis and enhanced degradation of the disc matrix proteoglycan (PG). How disc matrix PG homeostasis becomes perturbed with age is not known. The goal of this study is to determine whether cellular senescence is a source of this perturbation. We demonstrated that disc cellular senescence is dramatically increased in the DNA repair-deficient Ercc1 -/Δ mouse model of human progeria. In these accelerated aging mice, increased disc cellular senescence is closely associated with the rapid loss of disc PG. We also directly examine PG homeostasis in oxidative damage-induced senescent human cells using an in vitro cell culture model system. Senescence of human disc cells treated with hydrogen peroxide was confirmed by growth arrest, senescence-associated β-galactosidase activity, γH2AX foci, and acquisition of senescence-associated secretory phenotype. Senescent human disc cells also exhibited perturbed matrix PG homeostasis as evidenced by their decreased capacity to synthesize new matrix PG and enhanced degradation of aggrecan, a major matrix PG. of the disc. Our in vivo and in vitro findings altogether suggest that disc cellular senescence is an important driver of PG matrix homeostatic perturbation and PG loss. Published by Elsevier B.V.

  1. Experimental model of intervertebral disc degeneration by needle puncture in Wistar rats

    International Nuclear Information System (INIS)

    Issy, A.C.; Castania, V.; Castania, M.; Salmon, C.E.G.; Nogueira-Barbosa, M.H.; Bel, E. Del; Defino, H.L.A.

    2013-01-01

    Animal models of intervertebral disc degeneration play an important role in clarifying the physiopathological mechanisms and testing novel therapeutic strategies. The objective of the present study is to describe a simple animal model of disc degeneration involving Wistar rats to be used for research studies. Disc degeneration was confirmed and classified by radiography, magnetic resonance and histological evaluation. Adult male Wistar rats were anesthetized and submitted to percutaneous disc puncture with a 20-gauge needle on levels 6-7 and 8-9 of the coccygeal vertebrae. The needle was inserted into the discs guided by fluoroscopy and its tip was positioned crossing the nucleus pulposus up to the contralateral annulus fibrosus, rotated 360° twice, and held for 30 s. To grade the severity of intervertebral disc degeneration, we measured the intervertebral disc height from radiographic images 7 and 30 days after the injury, and the signal intensity T2-weighted magnetic resonance imaging. Histological analysis was performed with hematoxylin-eosin and collagen fiber orientation using picrosirius red staining and polarized light microscopy. Imaging and histological score analyses revealed significant disc degeneration both 7 and 30 days after the lesion, without deaths or systemic complications. Interobserver histological evaluation showed significant agreement. There was a significant positive correlation between histological score and intervertebral disc height 7 and 30 days after the lesion. We conclude that the tail disc puncture method using Wistar rats is a simple, cost-effective and reproducible model for inducing disc degeneration

  2. Experimental model of intervertebral disc degeneration by needle puncture in Wistar rats

    Energy Technology Data Exchange (ETDEWEB)

    Issy, A.C.; Castania, V.; Castania, M. [Departamento de Morfologia, Fisiologia e Patologia Básica, Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Salmon, C.E.G. [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Nogueira-Barbosa, M.H. [Divisão de Radiologia, Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Bel, E. Del [Departamento de Morfologia, Fisiologia e Patologia Básica, Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Defino, H.L.A. [Departamento de Biomecânica, Medicina e Reabilitação do Sistema Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2013-03-15

    Animal models of intervertebral disc degeneration play an important role in clarifying the physiopathological mechanisms and testing novel therapeutic strategies. The objective of the present study is to describe a simple animal model of disc degeneration involving Wistar rats to be used for research studies. Disc degeneration was confirmed and classified by radiography, magnetic resonance and histological evaluation. Adult male Wistar rats were anesthetized and submitted to percutaneous disc puncture with a 20-gauge needle on levels 6-7 and 8-9 of the coccygeal vertebrae. The needle was inserted into the discs guided by fluoroscopy and its tip was positioned crossing the nucleus pulposus up to the contralateral annulus fibrosus, rotated 360° twice, and held for 30 s. To grade the severity of intervertebral disc degeneration, we measured the intervertebral disc height from radiographic images 7 and 30 days after the injury, and the signal intensity T2-weighted magnetic resonance imaging. Histological analysis was performed with hematoxylin-eosin and collagen fiber orientation using picrosirius red staining and polarized light microscopy. Imaging and histological score analyses revealed significant disc degeneration both 7 and 30 days after the lesion, without deaths or systemic complications. Interobserver histological evaluation showed significant agreement. There was a significant positive correlation between histological score and intervertebral disc height 7 and 30 days after the lesion. We conclude that the tail disc puncture method using Wistar rats is a simple, cost-effective and reproducible model for inducing disc degeneration.

  3. Feasibility of minimally-invasive fiber-based evaluation of chondrodystrophoid canine intervertebral discs by light absorption and scattering spectroscopy

    Science.gov (United States)

    Jiang, Yuanyuan; McKeirnan, Kelci; Piao, Daqing; Bartels, Kenneth E.

    2011-03-01

    Extrusion or protrusion of an intervertebral disc is a common, frequently debilitating, painful, and sometimes fatal neurologic disease in the chondrodystrophic dog (dachshund, Pekingese, etc.). A similar condition of intervertebral disc degeneration with extrusion/protrusion is also a relatively common neurologic condition in human patients. Degeneration of the relatively avascular chondrodystrophoid intervertebral disc is associated with loss of water content, increased collagen, and deposits of calcified mineral in the nucleus pulposus. Current diagnostic methods have many limitations for providing accurate information regarding disc composition in situ prior to surgical intervention. Disc composition (i.e., mineralization), can influence the type of treatment regime and potentially prognosis and recurrence rates. The objective of this study is to investigate the feasibility of using a fiber-needle spectroscopy sensor to analyze the changes of tissue compositions involved in the chondrodystrophoid condition of the canine intervertebral disc. The nucleous pulposus, in which the metaplastic process / degeneration develops, is approximately 2mm thick and 5mm in diameter in the dachshund-sized dog. It lies in the center of the disc, surrounded by the annulus fibrosis and is enclosed by cartilaginous vertebral endplates cranially and caudally. This "shallow-and-small-slab" geometry limits the configuration of a fiber probe to sense the disc tissue volume without interference from the vertebrae. A single-fiber sensor is inserted into a 20 gauge myelographic spinal needle for insertion into the disc in situ and connected via a bifurcated fiber to the light source and a spectrometer. A tungsten light source and a 940nm light-emitting-diode are combined for spectral illumination covering VIS/NIR with expected improved sensitivity to water. Analysis of the reflectance spectra is expected to provide information of scattering and absorption compositions of tissue in

  4. Small vertebral cross-sectional area and tall intervertebral disc in adolescent idiopathic scoliosis

    Energy Technology Data Exchange (ETDEWEB)

    Ponrartana, Skorn; Fisher, Carissa L.; Aggabao, Patricia C. [Keck School of Medicine, University of Southern California, Department of Radiology, Children' s Hospital Los Angeles, Los Angeles, CA (United States); Chavez, Thomas A. [Keck School of Medicine, University of Southern California, Department of Pediatrics, Children' s Hospital Los Angeles, Los Angeles, CA (United States); Broom, Alexander M.; Wren, Tishya A.L.; Skaggs, David L. [Keck School of Medicine, University of Southern California, Department of Orthopaedic Surgery, Children' s Hospital Los Angeles, Los Angeles, CA (United States); Gilsanz, Vicente [Keck School of Medicine, University of Southern California, Department of Radiology, Children' s Hospital Los Angeles, Los Angeles, CA (United States); Keck School of Medicine, University of Southern California, Department of Pediatrics, Children' s Hospital Los Angeles, Los Angeles, CA (United States); Keck School of Medicine, University of Southern California, Department of Orthopaedic Surgery, Children' s Hospital Los Angeles, Los Angeles, CA (United States)

    2016-09-15

    When compared to boys, girls have smaller vertebral cross-sectional area, which conveys a greater spinal flexibility, and a higher prevalence of adolescent idiopathic scoliosis. To test the hypothesis that small vertebral cross-sectional area and tall intervertebral disc height are structural characteristics of patients with adolescent idiopathic scoliosis. Using multiplanar imaging techniques, measures of vertebral cross-sectional area, vertebral height and intervertebral disc height in the lumbar spine were obtained in 35 pairs of girls and 11 pairs of boys with and without adolescent idiopathic scoliosis of the thoracic spine matched for age, height and weight. Compared to adolescents without spinal deformity, girls and boys with adolescent idiopathic scoliosis had, on average, 9.8% (6.68 ± 0.81 vs. 7.40 ± 0.99 cm{sup 2}; P = 0.0007) and 13.9% (8.22 ± 0.84 vs. 9.55 ± 1.61 cm{sup 2}; P = 0.009) smaller vertebral cross-sectional dimensions, respectively. Additionally, patients with adolescent idiopathic scoliosis had significantly greater values for intervertebral disc heights (9.06 ± 0.85 vs. 7.31 ± 0.62 mm and 9.09 ± 0.87 vs. 7.61 ± 1.00 mm for girls and boys respectively; both P ≤ 0.011). Multiple regression analysis indicated that the presence of scoliosis was negatively associated with vertebral cross-sectional area and positively with intervertebral disc height, independent of sex, age and body mass index. We provide new evidence that girls and boys with adolescent idiopathic scoliosis have significantly smaller vertebral cross-sectional area and taller intervertebral disc heights - two major structural determinants that influence trunk flexibility. With appropriate validation, these findings may have implications for the identification of children at the highest risk for developing scoliosis. (orig.)

  5. Small vertebral cross-sectional area and tall intervertebral disc in adolescent idiopathic scoliosis

    International Nuclear Information System (INIS)

    Ponrartana, Skorn; Fisher, Carissa L.; Aggabao, Patricia C.; Chavez, Thomas A.; Broom, Alexander M.; Wren, Tishya A.L.; Skaggs, David L.; Gilsanz, Vicente

    2016-01-01

    When compared to boys, girls have smaller vertebral cross-sectional area, which conveys a greater spinal flexibility, and a higher prevalence of adolescent idiopathic scoliosis. To test the hypothesis that small vertebral cross-sectional area and tall intervertebral disc height are structural characteristics of patients with adolescent idiopathic scoliosis. Using multiplanar imaging techniques, measures of vertebral cross-sectional area, vertebral height and intervertebral disc height in the lumbar spine were obtained in 35 pairs of girls and 11 pairs of boys with and without adolescent idiopathic scoliosis of the thoracic spine matched for age, height and weight. Compared to adolescents without spinal deformity, girls and boys with adolescent idiopathic scoliosis had, on average, 9.8% (6.68 ± 0.81 vs. 7.40 ± 0.99 cm 2 ; P = 0.0007) and 13.9% (8.22 ± 0.84 vs. 9.55 ± 1.61 cm 2 ; P = 0.009) smaller vertebral cross-sectional dimensions, respectively. Additionally, patients with adolescent idiopathic scoliosis had significantly greater values for intervertebral disc heights (9.06 ± 0.85 vs. 7.31 ± 0.62 mm and 9.09 ± 0.87 vs. 7.61 ± 1.00 mm for girls and boys respectively; both P ≤ 0.011). Multiple regression analysis indicated that the presence of scoliosis was negatively associated with vertebral cross-sectional area and positively with intervertebral disc height, independent of sex, age and body mass index. We provide new evidence that girls and boys with adolescent idiopathic scoliosis have significantly smaller vertebral cross-sectional area and taller intervertebral disc heights - two major structural determinants that influence trunk flexibility. With appropriate validation, these findings may have implications for the identification of children at the highest risk for developing scoliosis. (orig.)

  6. Precision of lumbar intervertebral measurements: does a computer-assisted technique improve reliability?

    Science.gov (United States)

    Pearson, Adam M; Spratt, Kevin F; Genuario, James; McGough, William; Kosman, Katherine; Lurie, Jon; Sengupta, Dilip K

    2011-04-01

    Comparison of intra- and interobserver reliability of digitized manual and computer-assisted intervertebral motion measurements and classification of "instability." To determine if computer-assisted measurement of lumbar intervertebral motion on flexion-extension radiographs improves reliability compared with digitized manual measurements. Many studies have questioned the reliability of manual intervertebral measurements, although few have compared the reliability of computer-assisted and manual measurements on lumbar flexion-extension radiographs. Intervertebral rotation, anterior-posterior (AP) translation, and change in anterior and posterior disc height were measured with a digitized manual technique by three physicians and by three other observers using computer-assisted quantitative motion analysis (QMA) software. Each observer measured 30 sets of digital flexion-extension radiographs (L1-S1) twice. Shrout-Fleiss intraclass correlation coefficients for intra- and interobserver reliabilities were computed. The stability of each level was also classified (instability defined as >4 mm AP translation or 10° rotation), and the intra- and interobserver reliabilities of the two methods were compared using adjusted percent agreement (APA). Intraobserver reliability intraclass correlation coefficients were substantially higher for the QMA technique THAN the digitized manual technique across all measurements: rotation 0.997 versus 0.870, AP translation 0.959 versus 0.557, change in anterior disc height 0.962 versus 0.770, and change in posterior disc height 0.951 versus 0.283. The same pattern was observed for interobserver reliability (rotation 0.962 vs. 0.693, AP translation 0.862 vs. 0.151, change in anterior disc height 0.862 vs. 0.373, and change in posterior disc height 0.730 vs. 0.300). The QMA technique was also more reliable for the classification of "instability." Intraobserver APAs ranged from 87 to 97% for QMA versus 60% to 73% for digitized manual

  7. Hedgehog signaling is required for formation of the notochord sheath and patterning of nuclei pulposi within the intervertebral discs

    OpenAIRE

    Choi, Kyung-Suk; Harfe, Brian D.

    2011-01-01

    The vertebrae notochord is a transient rod-like structure that produces secreted factors that are responsible for patterning surrounding tissues. During later mouse embryogenesis, the notochord gives rise to the middle part of the intervertebral disc, called the nucleus pulposus. Currently, very little is known about the molecular mechanisms responsible for forming the intervertebral discs. Here we demonstrate that hedgehog signaling is required for formation of the intervertebral discs. Remo...

  8. Sonic hedgehog in the notochord is sufficient for patterning of the intervertebral discs.

    Science.gov (United States)

    Choi, Kyung-Suk; Lee, Chanmi; Harfe, Brian D

    2012-01-01

    The intervertebral discs, located between adjacent vertebrae, are required for stability of the spine and distributing mechanical load throughout the vertebral column. All cell types located in the middle regions of the discs, called nuclei pulposi, are derived from the embryonic notochord. Recently, it was shown that the hedgehog signaling pathway plays an essential role during formation of nuclei pulposi. However, during the time that nuclei pulposi are forming, Shh is expressed in both the notochord and the nearby floor plate. To determine the source of SHH protein sufficient for formation of nuclei pulposi we removed Shh from either the floor plate or the notochord using tamoxifen-inducible Cre alleles. Removal of Shh from the floor plate resulted in phenotypically normal intervertebral discs, indicating that Shh expression in this tissue is not required for disc patterning. In addition, embryos that lacked Shh in the floor plate had normal vertebral columns, demonstrating that Shh expression in the notochord is sufficient for pattering the entire vertebral column. Removal of Shh from the notochord resulted in the absence of Shh in the floor plate, loss of intervertebral discs and vertebral structures. These data indicate that Shh expression in the notochord is sufficient for patterning of the intervertebral discs and the vertebral column. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  9. Disk

    NARCIS (Netherlands)

    P.A. Boncz (Peter); L. Liu (Lei); M. Tamer Özsu

    2008-01-01

    htmlabstractIn disk storage, data is recorded on planar, round and rotating surfaces (disks, discs, or platters). A disk drive is a peripheral device of a computer system, connected by some communication medium to a disk controller. The disk controller is a chip, typically connected to the CPU of

  10. Pedicle distraction increases intervertebral and spinal canal area in a cadaver and bone model

    OpenAIRE

    Hughes Matthew; Papadakos Nikolaos; Bishop Tim; Bernard Jason

    2018-01-01

    Introduction: Lumbar spinal stenosis is degenerative narrowing of the spinal canal and/or intervertebral foramen causing compression of the spinal cord and nerve roots. Traditional decompression techniques can often cause significant trauma and vertebral instability. This paper evaluates a method of increasing pedicle length to decompress the spinal and intervertebral foramen, which could be done minimally invasive. Methods: Three Sawbone (Sawbones Europe, Sweden) and 1 cadaveric lumbar sp...

  11. MRI findings and diagnostic value of intervertebral disc free pulpiform nucleus in lumbar intraspinal

    International Nuclear Information System (INIS)

    Cai Jinhua; Fang Huasheng; Li Dongyuan

    2011-01-01

    Objective: To determine the MRI findings and diagnostic value of intervertebral disc free pulpiform nucleus in lumbar intraspinal. Methods: MRI findings of 46 cases with free pulpiform nucleus proved by surgery and pathology were retrospectively analyzed, and compared with pathological results. Results: Of all cases, the free pulpiform nucleus located at extradural foreside. 9 cases of the free pulpiform nucleus dissociated upon in spinal, 32 cases moved down and 5 cases removed backwards. Of 46 patients, 22 cases of the free pulpiform nucleus inhabited right, 17 cases left and 7 cases in midline. The lesion was single in all case with round, oval or anormaly shape. The free pulpiform nucleus had the same equal or low signal with provided intervertebral disc. The calcification, if any, presented as low -signal area. Among these 11 cases which were injected with GD-DTPA had no enhancement in the center, mild and high enhancement at periphery. Among all cases, MRI diagnosis were agreed with the pathology results with diagnosis accuracy of 100%. Conclusion: MRI can clearly demonstrate the intervertebral disc free pulpiform nucleus in lumbar intraspinal and make a correct diagnosis. Therefore, MRI is the best choice for diagnosis of intervertebral disc free pulpiform nucleus in lumbar intraspinal. (authors)

  12. Protective effects of cannabidiol on lesion-induced intervertebral disc degeneration.

    Directory of Open Access Journals (Sweden)

    João W Silveira

    Full Text Available Disc degeneration is a multifactorial process that involves hypoxia, inflammation, neoinnervation, accelerated catabolism, and reduction in water and glycosaminoglycan content. Cannabidiol is the main non-psychotropic component of the Cannabis sativa with protective and anti-inflammatory properties. However, possible therapeutic effects of cannabidiol on intervertebral disc degeneration have not been investigated yet. The present study investigated the effects of cannabidiol intradiscal injection in the coccygeal intervertebral disc degeneration induced by the needle puncture model using magnetic resonance imaging (MRI and histological analyses. Disc injury was induced in the tail of male Wistar rats via a single needle puncture. The discs selected for injury were punctured percutaneously using a 21-gauge needle. MRI and histological evaluation were employed to assess the results. The effects of intradiscal injection of cannabidiol (30, 60 or 120 nmol injected immediately after lesion were analyzed acutely (2 days by MRI. The experimental group that received cannabidiol 120 nmol was resubmitted to MRI examination and then to histological analyses 15 days after lesion/cannabidiol injection. The needle puncture produced a significant disc injury detected both by MRI and histological analyses. Cannabidiol significantly attenuated the effects of disc injury induced by the needle puncture. Considering that cannabidiol presents an extremely safe profile and is currently being used clinically, these results suggest that this compound could be useful in the treatment of intervertebral disc degeneration.

  13. Biomechanical analysis of the camelid cervical intervertebral disc

    Directory of Open Access Journals (Sweden)

    Dean K. Stolworthy

    2015-01-01

    Full Text Available Chronic low back pain (LBP is a prevalent global problem, which is often correlated with degenerative disc disease. The development and use of good, relevant animal models of the spine may improve treatment options for this condition. While no animal model is capable of reproducing the exact biology, anatomy, and biomechanics of the human spine, the quality of a particular animal model increases with the number of shared characteristics that are relevant to the human condition. The purpose of this study was to investigate the camelid (specifically, alpaca and llama cervical spine as a model of the human lumbar spine. Cervical spines were obtained from four alpacas and four llamas and individual segments were used for segmental flexibility/biomechanics and/or morphology/anatomy studies. Qualitative and quantitative data were compared for the alpaca and llama cervical spines, and human lumbar specimens in addition to other published large animal data. Results indicate that a camelid cervical intervertebral disc (IVD closely approximates the human lumbar disc with regard to size, spinal posture, and biomechanical flexibility. Specifically, compared with the human lumbar disc, the alpaca and llama cervical disc size are approximately 62%, 83%, and 75% with regard to area, depth, and width, respectively, and the disc flexibility is approximately 133%, 173%, and 254%, with regard to range of motion (ROM in axial-rotation, flexion-extension, and lateral-bending, respectively. These results, combined with the clinical report of disc degeneration in the llama lower cervical spine, suggest that the camelid cervical spine is potentially well suited for use as an animal model in biomechanical studies of the human lumbar spine.

  14. The collagen structure of bovine intervertebral disc studied using polarization-sensitive optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Matcher, Stephen J; Winlove, C Peter; Gangnus, Sergei V [Present address: JSC ' Saratovneftegeophysics' , Saratov (Russian Federation)

    2004-04-07

    Polarization-sensitive optical coherence tomography (PS-OCT) is used to measure the birefringence properties of bovine intervertebral disc and equine flexor tendon. For equine tendon the birefringence {delta}n is (6.0 {+-} 0.2) x 10{sup -3} at a wavelength of 1.3 {mu}m. This is somewhat larger than the values reported for bovine tendon. The surface region of the annulus fibrosus of a freshly excised intact bovine intervertebral disc displays an identical value of birefringence, {delta}n = (6.0 {+-} 0.6) x 10{sup -3} at 1.3 {mu}m. The nucleus pulposus does not display birefringence, the measured apparent value of {delta}n = (0.39 {+-} 0.01) x 10{sup -3} being indistinguishable from the effects of depolarization due to multiple scattering. A clear difference is found between the depth-resolved retardance of equine tendon and that of bovine intervertebral disc. This apparently relates to the lamellar structure of the latter tissue, in which the collagen fibre orientation alternates between successive lamellae. A semi-empirical model based on Jones calculus shows that the measurements are in reasonable agreement with previous optical and x-ray data. These results imply that PS-OCT could be a useful tool to study collagen organization within the intervertebral disc in vitro and possibly in vivo and its variation with applied load and disease.

  15. The collagen structure of bovine intervertebral disc studied using polarization-sensitive optical coherence tomography

    International Nuclear Information System (INIS)

    Matcher, Stephen J; Winlove, C Peter; Gangnus, Sergei V

    2004-01-01

    Polarization-sensitive optical coherence tomography (PS-OCT) is used to measure the birefringence properties of bovine intervertebral disc and equine flexor tendon. For equine tendon the birefringence Δn is (6.0 ± 0.2) x 10 -3 at a wavelength of 1.3 μm. This is somewhat larger than the values reported for bovine tendon. The surface region of the annulus fibrosus of a freshly excised intact bovine intervertebral disc displays an identical value of birefringence, Δn = (6.0 ± 0.6) x 10 -3 at 1.3 μm. The nucleus pulposus does not display birefringence, the measured apparent value of Δn = (0.39 ± 0.01) x 10 -3 being indistinguishable from the effects of depolarization due to multiple scattering. A clear difference is found between the depth-resolved retardance of equine tendon and that of bovine intervertebral disc. This apparently relates to the lamellar structure of the latter tissue, in which the collagen fibre orientation alternates between successive lamellae. A semi-empirical model based on Jones calculus shows that the measurements are in reasonable agreement with previous optical and x-ray data. These results imply that PS-OCT could be a useful tool to study collagen organization within the intervertebral disc in vitro and possibly in vivo and its variation with applied load and disease

  16. Human cartilaginous endplate degeneration is induced by calcium and the extracellular calcium-sensing receptor in the intervertebral disc

    Directory of Open Access Journals (Sweden)

    MP Grant

    2016-07-01

    Full Text Available The cartilaginous endplates (CEPs are thin layers of hyaline cartilage found adjacent to intervertebral discs (IVDs. In addition to providing structural support, CEPs regulate nutrient and metabolic exchange in the disc. In IVD pathogenesis, CEP undergoes degeneration and calcification, compromising nutrient availability and disc cell metabolism. The mechanism(s underlying the biochemical changes of CEP in disc degeneration are currently unknown. Since calcification is often observed in later stages of IVD degeneration, we hypothesised that elevations in free calcium (Ca2+ impair CEP homeostasis. Indeed, our results demonstrated that the Ca2+ content was consistently higher in human CEP tissue with grade of disc degeneration. Increasing the levels of Ca2+ resulted in decreases in the secretion and accumulation of collagens type I, II and proteoglycan in cultured human CEP cells. Ca2+ exerted its effects on CEP matrix protein synthesis through activation of the extracellular calcium-sensing receptor (CaSR; however, aggrecan content was also affected independent of CaSR activation as increases in Ca2+ directly enhanced the activity of aggrecanases. Finally, supplementing Ca2+ in our IVD organ cultures was sufficient to induce degeneration and increase the mineralisation of CEP, and decrease the diffusion of glucose into the disc. Thus, any attempt to induce anabolic repair of the disc without addressing Ca2+ may be impaired, as the increased metabolic demand of IVD cells would be compromised by decreases in the permeability of the CEP.

  17. Standards of Practice: Quality Assurance Guidelines for Percutaneous Treatments of Intervertebral Discs

    International Nuclear Information System (INIS)

    Kelekis, Alexis D.; Filippiadis, Dimitris K.; Martin, Jean-Baptiste; Brountzos, Elias

    2010-01-01

    Percutaneous treatments are used in the therapy of small- to medium-sized hernias of intervertebral discs to reduce the intradiscal pressure in the nucleus and theoretically create space for the herniated fragment to implode inward, thus reducing pain and improving mobility and quality of life. These techniques involve the percutaneous removal of the nucleus pulposus by using a variety of chemical, thermal, or mechanical techniques and consist of removal of all or part of nucleus pulposus to induce more rapid healing of the abnormal lumbar disc. These guidelines are written to be used in quality improvement programs for assessing fluoroscopy- and/or computed tomography-guided percutaneous intervertebral disc ablative techniques.

  18. In vivo effects of bupivacaine and gadobutrol on the intervertebral disc following discoblock and discography: a histological analysis.

    Science.gov (United States)

    Strube, Patrick; Pfitzner, Berit M; Streitparth, Florian; Hartwig, Tony; Putzier, Michael

    2017-01-01

    The aim of the present study was to histologically compare chondrotoxicity in surgically harvested intervertebral discs (IVDs) of patients following discoblock, discography, or no preoperative intervention. Thirty patients (IVD degeneration Modic ≥ 2°, Pfirrmann 3° or 4°) at L4/5 or L5/S1 who were planned for anterior lumbar interbody fusion were randomly assigned to three groups (open MRI: group DG - discography with gadobutrol; group DB - discoblock with bupivacaine at 4 weeks prior to surgery; group C - no intervention). The intervertebral discs were histologically evaluated and compared using ANOVA and Bonferroni tests for cell count, apoptosis, and proliferation. A reduced cell count (groups DG vs. DB vs. C: 14.9 ± 7.1, 9.2 ± 3.8, and 16.6 ± 5.2 cells/mm 2 , respectively; p ANOVA  = 0.016), increased apoptosis (groups DG vs. DB vs. C: 34.9 ± 10.2, 47.4 ± 16.3, 32.6 ± 12.2 %, respectively; p ANOVA  = 0.039) and increased cell proliferation (post hoc pDB vs. DG or C p bupivacaine but not after gadobutrol administration. • Local bupivacaine administration to intervertebral discs leads to cell toxicity and proliferation. • Gadobutrol demonstrated no significant effect on cell count, apoptosis, or cell proliferation. • In vivo cytotoxicity was demonstrated histologically in humans for the first time. • Addition/administration of bupivacaine during discographies must be judged critically.

  19. Development of a computerized intervertebral motion analysis of the cervical spine for clinical application.

    Science.gov (United States)

    Piché, Mathieu; Benoît, Pierre; Lambert, Julie; Barrette, Virginie; Grondin, Emmanuelle; Martel, Julie; Paré, Amélie; Cardin, André

    2007-01-01

    The objective of this study was to develop a measurement method that could be implemented in chiropractic for the evaluation of angular and translational intervertebral motion of the cervical spine. Flexion-extension radiographs were digitized with a scanner at a ratio of 1:1 and imported into a software, allowing segmental motion measurements. The measurements were obtained by selecting the most anteroinferior point and the most posteroinferior point of a vertebral body (anterior and posterior arch, respectively, for C1), with the origin of the reference frame set at the most posteroinferior point of the vertebral body below. The same procedure was performed for both the flexion and extension radiographs, and the coordinates of the 2 points were used to calculate the angular movement and the translation between the 2 vertebrae. This method provides a measure of intervertebral angular and translational movement. It uses a different reference frame for each joint instead of the same reference frame for all joints and thus provides a measure of motion in the plane of each articulation. The calculated values obtained are comparable to other studies on intervertebral motion and support further development to validate the method. The present study proposes a computerized procedure to evaluate intervertebral motion of the cervical spine. This procedure needs to be validated with a reliability study but could provide a valuable tool for doctors of chiropractic and further spinal research.

  20. Inflammatory microRNA-194 and -515 attenuate the biosynthesis of chondroitin sulfate during human intervertebral disc degeneration.

    Science.gov (United States)

    Hu, Bo; Xu, Chen; Tian, Ye; Shi, Changgui; Zhang, Ying; Deng, Lianfu; Zhou, Hongyu; Cao, Peng; Chen, Huajiang; Yuan, Wen

    2017-07-25

    Intervertebral disc degeneration (IDD) is characterized by dehydration and loss of extracellular matrixes in the nucleus pulposus region. Chondroitin sulfate has been found to be the water-binding molecule that played a key role in IDD. Although investigators have reported that inflammatory cytokines are involved in the reduction of chondroitin sulfate in IDD, but the underlying mechanism is unrevealed. Since chondroitin sulfate synthesis is controlled by chondroitin sulfate glycosyltransferases CHSY-1/2/3 and CSGALNACT-1/2, their functional role and regulatory mechanism in IDD is not fully studied. Here, we set out to investigate the function and regulatory roles of these factors during IDD development. We found that among these chondroitin sulfate glycosyltransferases, CHSY-1/2/3 are significantly down-regulated in severe IDD samples than mild IDD samples. In vitro experiments revealed that Interleukin-1β and Tumor Necrosis Factor-α stimulation led to significant reduction of CHSY-1/2/3 at protein level than mRNA level in NP cells, indicating a post-transcriptional regulatory mechanisms are involved. By computational prediction and analysis, we found that inflammatory cytokines stimulated microRNA-194 and -515 target CHSY-1/2/3 mRNA and significantly interrupt their translation and downstream chondroitin sulfate deposition. Inhibition of microRNA-194 and -515 however, significantly rescued CHSY-1/2/3 expressions and chondroitin sulfate deposition. These findings together demonstrated a vital role of inflammatory stimulated microRNAs in promoting intervertebral disc degeneration by interrupt chondroitin sulfate synthesis, which may provide new insights into the mechanism and therapeutic approaches in IDD.

  1. Imaging of degenerative lumbar intervertebral discs; linking anatomy, pathology and imaging.

    Science.gov (United States)

    Adams, Ashok; Roche, Oran; Mazumder, Asif; Davagnanam, Indran; Mankad, Kshitij

    2014-09-01

    Low back pain is a common medical condition that has significant implications for healthcare providers and the UK economy. Low back pain can be classified as 'specific' in which an underlying pathophysiological mechanism is identified (eg, herniated intervertebral disc). Advanced imaging should be performed in this situation and in those patients in whom systemic disease is strongly suspected. In the majority (approximately 90%), low back pain in 'non specific' and there is a weak correlation with imaging abnormalities. This is an area of ongoing research and remains controversial in terms of imaging approach and treatment (eg, theory of discogenic pain, interpretation and treatment of endplate changes). With regards Modic endplate changes, current research suggests that an infective component may be involved that may identify novel potential treatments in patients with chronic low back pain refractory to other treatment modalities. MRI is the imaging modality of choice for the assessment of degenerative changes in intervertebral discs. MRI has superior soft tissue contrast resolution when compared to other imaging modalities (eg, plain radiography, CT). An understanding of normal anatomy and MR appearances of intervertebral discs, particularly with regards to how these appearances change with advancing age, is required to aid image interpretation. Knowledge of the spectrum of degenerative processes that may occur in the intervertebral discs is required in order to identify and explain abnormal MRI appearances. As the communication of MRI findings may guide therapeutic decision making and surgical intervention, the terminology used by radiologists must be accurate and consistent. Therefore, description of degenerative disc changes in the current paper is based on the most up-to-date recommendations, the aim being to aid reporting by radiologists and interpretation of reports by referring clinicians. Published by the BMJ Publishing Group Limited. For permission to

  2. Evaluation of intravertebral changes associated with the disk degeneration based on the MRI findings

    International Nuclear Information System (INIS)

    Saiki, Natoru

    2000-01-01

    The magnetic resonance images (MRI) of 441 vertebral bodies of the 199 patients with intravertebral abnormality associated with adjacent disk degeneration were evaluated according to the Modic classification and a new geographic classification. They were also evaluated in relation with the various factors including disk space narrowing, vacuum phenomenon, disk herniation, Schmorl's node, ostephyte formation and spondylolisthesis. The new geographic classification is based on the three factors; depth of invasion: stage 1 (thin layer along the end-plate), stage 2 (less than a half of the vertebral height) and stage 3 (more than a half of the vertebral height), shape: end-plate type, Schmorl's node type, triangle type, meniscus type and band type, location: front type, center type, rear type, front and rear type and whole type. Only about a half of the vertebral bodies with intervertebral abnormality showed bilateral invasion adjacent to the degenerative disks on both sides and the superior edges were much more frequently involved than the inferior ones. There was relatively higher incidence (7%) of Modic Type I degeneration defined as high signal intensity (HSI) on T2 weighted spin-echo images (T2WI) and low signal intensity (LSI) on T1 weighted spin-echo images (T1WI) representing vascularized fibrous tissue than those previously reported. On the other hand there was relatively lower incidence (5%) of Modic Type II degeneration defined as high or iso intensity on T1WI and HSI on T2WI. Triangle front type was seen in almost a half of the vertebrae in stage 2 and stage 3, and the rest was divided into meniscus type and band type almost evenly. The end plate front type must be a precursor of the triangle front type. The Schmorl's node type was considered to be a precursor of the meniscus type as well as band type in some but many must stay in its form transformed to Type II degeneration. In general, the intravertebral abnormality may not be necessary to be progressive

  3. Radiofrequency thermocoagulation for the treatment of lumbar intervertebral disc protrusion: a clinical observation of 30 cases

    International Nuclear Information System (INIS)

    Gong Weidong; Li Yazhou; Cao Wei; Yang Wei; Zhang Peng; Wang Zhimin; Wu Zhiqun

    2010-01-01

    Objective: To observe the clinical effects and safety of radiofrequency thermocoagulation in treating the lumbar intervertebral disc protrusion. Methods: Thirty patients with lumbar intervertebral disc protrusion, whose diagnoses were confirmed by clinical manifestations and CT findings, were involved in this study. The needle was punctured to the target point of the diseased intervertebral space under C-arm fluoroscopic guidance. After the testing of sensory nerve, motor nerve and temperature was made, the target needles were heated until the nerve radiofrequency temperature meter reached the point of 92 degree C. This point of temperature was held for 100 seconds and the procedure was repeated for four cycles. Results: Six months after the treatment, all patients showed an obvious improvement in VAS, which decreased from 7.83 ± 0.33 before operation to 2.37 ± 0.48 after treatment (P < 0.05). According to the modified Macnab therapeutic evaluation criteria, excellent result was seen in 9, good result in 12, fair result in 5 and poor result in 4 cases, with a total effective rate of 86.7%. No serious complications occurred in all patients. Conclusion: Radiofrequency thermocoagulation is an effective and safe method for the treatment of lumbar intervertebral disc protrusion. (authors)

  4. Evaluation of effects of selected factors on inter-vertebral fusion-a simulation study.

    Science.gov (United States)

    Wang, Xiaobo; Dumas, Geneviève A

    2005-04-01

    This study simulated the effects of inter-vertebral disc degeneration and bone density distribution on the structural stiffness and strength provided by inter-vertebral fusion. Based on the original and redistributed bone density distributions, the effects of selected factors, including contact area between device/graft and vertebral endplates, endplate conditions, and bone growth capacity were evaluated using a factorial design of experiment. The simulation results suggested that the degeneration of inter-vertebral disc significantly affected the bone density and density distribution in adjacent vertebrae. The mechanical strength immediately after instrumentation is the worst case of device/graft subsidence. After that procedure, bone will adapt itself to the changed loading conditions and therefore reduce the risk of subsidence. A deficiency in structural stiffness immediately after instrumentation could be the "worst-case scenario" depending on the combinations of selected factors. The simulation results demonstrated that the contact area and initial bone density distribution should be considered jointly while estimating the risk of device/graft subsidence. The endplate condition is a secondary factor on the subsidence risk, compared with the contact area and initial bone density distribution.

  5. The effect of ex vivo flexion and extension on intervertebral foramina dimensions in the equine cervical spine.

    Science.gov (United States)

    Sleutjens, J; Voorhout, G; Van Der Kolk, J H; Wijnberg, I D; Back, W

    2010-11-01

    In dressage, the head and neck position has become an issue of concern as certain extreme positions may imply a welfare risk for the horse. In man, extension and flexion of the cervical spine cause a decrease and increase in intervertebral foramina dimensions, respectively. However, in horses, the influence of flexion and extension on foramina dimensions and its possible interference with peripheral nerve functioning remains unknown. To determine the effect of ex vivo flexion and extension on intervertebral foramina dimensions in the equine cervical spine. Computed tomography was performed on 6 cadaver cervical spines from adult Warmblood horses subjected to euthanasia for reasons unrelated to cervical spine abnormalities, in a neutral position, in 20 and 40° extension, and in 20 and 40° flexion. Multiplanar reconstructions were made to obtain transverse images perpendicular to the long axis of each pair of intervertebral foramina from C2-T1. Intervertebral foramina dimensions were measured in the 5 positions. Compared to the neutral position, 40° extension caused a decrease in foramina dimensions at segments C4-C5, C5-C6, C6-C7 (P dimensions at segments C5-C6 (P dimensions at segments C4-T1, similar to that found in man. In vivo extension of the cervical spine could possibly interfere with peripheral nerve functioning at segments C4-T1. This effect may be even more profound in patients with a reduced intervertebral foramina space, for example in the presence of facet joint arthrosis. © 2010 EVJ Ltd.

  6. Intervertebral Disc Characteristic on Progressive Neurological Deficit

    Directory of Open Access Journals (Sweden)

    Farid Yudoyono

    2017-09-01

    Full Text Available Objective: To examine the intervertebral disc characteristic on magnetic resonance imaging (MRI in lumbar herniated disc (LHD patients with progressive neurological deficit. Methods: Patients were collected retrospectively from Dr. Hasan Sadikin General Hospital Database from 2011–2013 with LHD, had neurological deficit such as radiculopathy and cauda equine syndrome for less than four weeks with a positive sign confirmed by neurological examination and confirmatory with MRI examination. Results: A total of 14 patients with lumbar herniated disc disease (10 males, 4 females suffered from progressive neurological deficit with an average age of (52.07±10.9 years old. Early disc height was 9.38±0.5 mm and progressive neurological deficit state disc height was 4.03±0.53 mm, which were significantly different statisticaly (p<0.01. Symptoms of radiculopathy were seen in 11 patients and cauda equine syndrome in three patients. Modic changes grade 1 was found in five patients, grade 2 in eight patients,grade 3 in one patient, Pfirmman grade 2 in eleven patients and grade 3 in three patients. Thecal sac compression 1/3 compression was seen in four patients and 2/3 compression in ten patients. Conclusions: Neurosurgeon should raise concerns on the characteristic changes of intervertebral disc in magnetic resonance imaging examination to avoid further neural injury in lumbar herniated disc patients.

  7. Potential regenerative treatment strategies for intervertebral disc degeneration in dogs

    NARCIS (Netherlands)

    Bach, Frances C; Willems, Nicole; Penning, Louis C; Ito, Keita; Meij, Björn P; Tryfonidou, Marianna A

    Pain due to spontaneous intervertebral disc (IVD) disease is common in dogs. In chondrodystrophic (CD) dogs, IVD disease typically develops in the cervical or thoracolumbar spine at about 3-7 years of age, whereas in non-chondrodystrophic (NCD) dogs, it usually develops in the caudal cervical or

  8. Comparison study on CNR and SNR of thoracic spine lateral radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Won [Dept. of Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Min, Jung Whan; Lyu, Kwang Yeul [Dept. of Radiology, Shingu University, Sungnam (Korea, Republic of); Kim, Jung Min [Dept. of Radiological Science, College of Health Science, Korea University, Seoul (Korea, Republic of); Jeong, Hei Woun [Dept. of Radiological Science, Beakseok Culture University, Cheonan (Korea, Republic of); Lee, Joo Ah [Dept. of Oncology, Catholic University of Korea Incheon St.Mary,s Hospital, Incheon (Korea, Republic of); Jung, Jae Hong [Dept. of Oncology, Soonchunhyang University Bucheon Hospital, Bucheon (Korea, Republic of); Sung, Dong Chan [Dept. of Radiology, Dong Guk University Medical Center, Seoul (Korea, Republic of); Park, Soon Cheol [Dept. of Radiology, Kang Dong Kyung Hee University Medical Center, Seoul (Korea, Republic of)

    2013-12-15

    This study was proven for the T-spine breathing technique in lateral projection, using computer radiography (CR), charge coupled device (CCD), indirect digital radiography (IDR) and direct digital radiography (DDR). All images were evaluated and compared with CNR and SNR measured with the mean pixels and the standard deviation as setting ROI of spinous process, pedicle, vertebral body, intervertebral foramen and intervertebral disk using Image J. In experiment results of 4 type detectors, T-spine breathing technique was indicated as excellent in ROI of spinous process, pedicle, vertebral body, intervertebral foramen and intervertebral disk. As T-spine breathing technique indicated excellent images compared to the existing T-spine lateral radiography, this method would be useful for elderly patients who have difficulty in deep exhalation. This study was indicated the application possibility of T-spine breathing technique by presenting contrast to noise ratio (CNR) and signal to noise ratio (SNR) with quantitative value in 4 type detectors.

  9. Remodelamento da matriz extracelular em degeneração experimental do disco intervertebral

    OpenAIRE

    Oliveira,Cintia Pereira de; Rodrigues,Luciano Miller Reis; Fregni,Maria Vitória Ventura Dias; Gotfryd,Alberto; Made,Ana Maria; Pinhal,Maria Aparecida da Silva

    2013-01-01

    OBJETIVO: Avaliar a remodelação da matriz extracelular na degeneração do disco intervertebral através do modelo experimental degeneração do disco intervertebral. MÉTODOS: O modelo de indução da degeneração discal, utilizando agulha 20G e rotação de 360º, foi aplicado por 30 segundos entre a sexta/sétima e oitava / nona vértebras coccígeas de ratos machos da linhagem Wistar. O nível intermediário, entre a sétima e oitava vértebras, foi tomado como controle, não sendo submetido à punção. A dist...

  10. Combined Therapies of Modified Taiyi Miraculous Moxa Roll and Cupping for Patients with Lumbar Intervertebral Disc Herniation.

    Science.gov (United States)

    Cai, Chunyue; Gong, Yuefeng; Dong, Dayong; Xue, Jinbiao; Zheng, Xiaoting; Zhong, Zhangfeng; Shao, Jialong; Mi, Daguo

    2018-01-01

    Lumbar intervertebral disc herniation is a kind of syndrome caused by stimulation or pressure of nerve root and cauda equina due to intervertebral disc disorder, fibrous ring rupture, and pulpiform nucleus protrusion. Application of traditional Chinese medicine (TCM) including acupuncture therapy and cupping therapy is unique and effective treatment for lumbar intervertebral disc herniation in China. Hence, we try to investigate the combined clinical efficacy of modified Taiyi miraculous moxa roll and cupping therapy on patients with lumbar intervertebral disc herniation. Seventy patients were randomly assigned into combined treatment group ( n = 35) and control group ( n = 35). The treatment group received combined therapy of modified Taiyi miraculous moxa roll and cupping therapy, while control group received acupuncture therapy alone. Diagnostic criteria of TCM syndrome, Japanese Orthopedic Association (JOA) score, and simplified McGill pain questionnaire (MPQ) were used to evaluate the therapy. 11 and 13 out of 35 subjects in the combined treatment group had improvement > 75% and between 50% and 75%, respectively. The corresponding number was 2 and 22 of 35 subjects in the acupuncture group. There was significant difference in the clinical efficacy between the treatment group and control group ( P = 0.036). The scores of JOA and MPQ detected in the patients of the two groups ( P cupping therapy or acupuncture. The combined or alone therapies can effectively improve the treatment efficacy in the patients with lumbar intervertebral disc herniation, while the combined therapies show more comparative effectiveness. Furthermore, the combined therapies are potentially safe and cost-effective and also benefit the improvement of short-term pain. Therefore, the combined therapies of the two ancient TCM deserve further clinical applications.

  11. Rabbit model of intervertebral disc degeneration by external compression device characterized by X-ray, MRI, histology, and cell viability

    Directory of Open Access Journals (Sweden)

    Ismail Ismail

    2006-12-01

    Full Text Available Appropriate experimental animal models, which mimic the degenerative process occurring in human intervertebral disc (IVD breakdown and can be used for new treatment studies such as tissue engineering or disc distraction are lacking. We studied the external compression device that used by Kroeber et al to create intervertebral disc degeneration in rabbit model characterized by X-ray, MRI, Histology, and Cell Viability. Ten NZW rabbit were randomly assigned to one of five groups. Intervertebral disc VL4-L5 are compressed using an external loading device, 1.9 MPa. First group rabbit are loaded for 14 days, second loaded for 28 days, thirth group are loaded for 14 days, and unloaded for 14 days, fourth group loaded for 28 days and unloaded for 28 days. The fifth group, rabbits underwent a sham operation. Additional, rabbits were used as sample for cell viability study. In disc height : sample in group one have biggest decreasing of disc height, that is 23.9 unit. In MRI assessment, the worst grade is grade 3. In histological score, the worst group is group three (58.69, and the best is group 4 (45.69. Group one have the largest dead cell, that are 403.5, and the smallest is group four (124.75. Trypan blue staining showed that group four have better viable cell (91.1 compare than group three (86.4. The study conclude disc degeneration can be created by external axial loading for 14 days in rabbit intervertebral disc. Duration of 28 days unloading gave better result for cells to recover. (Med J Indones 2006; 15:199-207  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Keywords: Rabbit model –intervertebral disc degeneration- external compression device-X-ray, MRI, Histology, and Cell viabilty /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso

  12. Measurement of Intervertebral Cervical Motion by Means of Dynamic X-Ray Image Processing and Data Interpolation

    Directory of Open Access Journals (Sweden)

    Paolo Bifulco

    2013-01-01

    Full Text Available Accurate measurement of intervertebral kinematics of the cervical spine can support the diagnosis of widespread diseases related to neck pain, such as chronic whiplash dysfunction, arthritis, and segmental degeneration. The natural inaccessibility of the spine, its complex anatomy, and the small range of motion only permit concise measurement in vivo. Low dose X-ray fluoroscopy allows time-continuous screening of cervical spine during patient’s spontaneous motion. To obtain accurate motion measurements, each vertebra was tracked by means of image processing along a sequence of radiographic images. To obtain a time-continuous representation of motion and to reduce noise in the experimental data, smoothing spline interpolation was used. Estimation of intervertebral motion for cervical segments was obtained by processing patient’s fluoroscopic sequence; intervertebral angle and displacement and the instantaneous centre of rotation were computed. The RMS value of fitting errors resulted in about 0.2 degree for rotation and 0.2 mm for displacements.

  13. Measurement of intervertebral cervical motion by means of dynamic x-ray image processing and data interpolation.

    Science.gov (United States)

    Bifulco, Paolo; Cesarelli, Mario; Romano, Maria; Fratini, Antonio; Sansone, Mario

    2013-01-01

    Accurate measurement of intervertebral kinematics of the cervical spine can support the diagnosis of widespread diseases related to neck pain, such as chronic whiplash dysfunction, arthritis, and segmental degeneration. The natural inaccessibility of the spine, its complex anatomy, and the small range of motion only permit concise measurement in vivo. Low dose X-ray fluoroscopy allows time-continuous screening of cervical spine during patient's spontaneous motion. To obtain accurate motion measurements, each vertebra was tracked by means of image processing along a sequence of radiographic images. To obtain a time-continuous representation of motion and to reduce noise in the experimental data, smoothing spline interpolation was used. Estimation of intervertebral motion for cervical segments was obtained by processing patient's fluoroscopic sequence; intervertebral angle and displacement and the instantaneous centre of rotation were computed. The RMS value of fitting errors resulted in about 0.2 degree for rotation and 0.2 mm for displacements.

  14. Clinical efficacy of bone cement injectable pedicle screw system combined with intervertebral fusion in treatment of lumbar spondylolysis and osteoporosis

    Directory of Open Access Journals (Sweden)

    Peng-yi DAI

    2016-10-01

    Full Text Available Objective  To observe the therapeutic effect of bone cement injectable pedicle screw system combined with intervertebral fusion for lumbar spondylolysis and osteoporosis. Methods  The clinical data were analyzed retrospectively of 21 patients with lumbar spondylolysis and osteoporosis who received treatment of bone cement injectable pedicle screw system and intervertebral fusion from Aug. 2013 to Nov. 2015. The 21 patients (9 males and 12 females aged from 60 to 80 years (mean 64 years old; 6 of them presented degenerative spondylolysis, 15 with isthmic spondylolisthesis; 2 cases had I degree slippage, 13 had Ⅱdegree slippage, 6 had Ⅲdegree slippage, and all the cases were unisegmental slippage including 9 cases in L4 and 12 cases in L5. Bone mineral density of lumbar vertebrae (L2-L5 was measured with dual-energy X-ray absorptiometry, and T values conforming to the diagnostic criteria of osteoporosis were less than or equal to -2.5; All patients were operated with whole lamina resection for decompression, bone cement injectable pedicle screws system implantation, propped open reduction and fixation intervertebral fusion. The clinical outcomes were determined by the radiographic evaluation including intervertebral height, height of intervertebral foramen, slip distance, slip rate and slip angle, and Oswestry disability index (ODI on preoperative, 3 months after operation and the end of the time, and the interbody fusion were followed up. Results  Cerebrospinal fluid leakage of incision was observed in two cases after operation, compression and dressing to incision, Trendelenburg position, dehydration and other treatments were taken, and the stitches of incisions were taken out on schedule. Slips in the 21 patients were reset to different extent, and lumbar physiological curvatures were recovered. The intervertebral height and height of intervertebral foramen were obviously higher 3 months after operation than that before operation (P0

  15. Identifying Likely Disk-hosting M dwarfs with Disk Detective

    Science.gov (United States)

    Silverberg, Steven; Wisniewski, John; Kuchner, Marc J.; Disk Detective Collaboration

    2018-01-01

    M dwarfs are critical targets for exoplanet searches. Debris disks often provide key information as to the formation and evolution of planetary systems around higher-mass stars, alongside the planet themselves. However, less than 300 M dwarf debris disks are known, despite M dwarfs making up 70% of the local neighborhood. The Disk Detective citizen science project has identified over 6000 new potential disk host stars from the AllWISE catalog over the past three years. Here, we present preliminary results of our search for new disk-hosting M dwarfs in the survey. Based on near-infrared color cuts and fitting stellar models to photometry, we have identified over 500 potential new M dwarf disk hosts, nearly doubling the known number of such systems. In this talk, we present our methodology, and outline our ongoing work to confirm systems as M dwarf disks.

  16. Fluid flow and convective transport of solutes within the intervertebral disc

    NARCIS (Netherlands)

    Ferguson, S.J.; Ito, K.; Nolte, L.P.

    2004-01-01

    Previous experimental and analytical studies of solute transport in the intervertebral disc have demonstrated that for small molecules diffusive transport alone fulfils the nutritional needs of disc cells. It has been often suggested that fluid flow into and within the disc may enhance the transport

  17. Cells and Biomaterials for Intervertebral Disc Regeneration

    CERN Document Server

    Grad, Sibylle

    2010-01-01

    Disorders related to the intervertebral disc (IVD) are common causes of morbidity and of severe life quality deterioration. IVD degeneration, although in many cases asymptomatic, is often the origin of painful neck and back diseases. In Western societies IVD related pain and disability account for enormous health care costs as a result of work absenteeism and thus lost production, disability benefits, medical and insurance expenses. Although only a small percentage of patients with disc disorders finally will undergo surgery, spinal surgery has been one of the fastest growing disciplines in th

  18. Quantification of Propionic Acid in the Bovine Spinal Disk After Infection of the Tissue With Propionibacteria acnes Bacteria.

    Science.gov (United States)

    Magnitsky, Sergey; Dudli, Stefan; Tang, Xinyan; Kaur, Jaskanwaljeet; Diaz, Joycelyn; Miller, Steve; Lotz, Jeffrey C

    2018-06-01

    Research. The goal of this study was to investigate whether Propionibacteria acnes infection of the intervertebral disc can be detected noninvasively by nuclear magnetic resonance (NMR) spectroscopy. Microbiological studies of surgical samples suggest that a significant subpopulation of back pain patients may have occult disc infection with P. acnes bacteria. This hypothesis is further supported by a double-blind clinical trial showing that back pain patients with Modic type 1 changes may respond to antibiotic treatment. Because significant side effects are associated with antibiotic treatment, there is a need for a noninvasive method to detect whether specific discs in back pain patients are infected with P acnes bacteria. P. acnes bacteria were obtained from human patients. NMR detection of a propionic acid (PA) in the bacteria extracts was conducted on 500 MHz high-resolution spectrometer, whereas in vivo NMR spectroscopy of an isolated bovine disk tissue infected with P. acnes was conducted on 7 T magnetic resonance imaging scanner. NMR spectra of P. acnes metabolites revealed a distinct NMR signal with identical chemical shits (1.05 and 2.18 ppm) as PA (a primary P. acne metabolite). The 1.05 ppm signal does not overlap with other bacteria metabolites, and its intensity increases linearly with P. acnes concentration. Bovine disks injected with P. acnes bacteria revealed a very distinct NMR signal at 1.05 ppm, which linearly increased with P. acnes concentration. The 1.05 ppm NMR signal from PA can be used as a marker of P. acnes infection of discs. This signal does not overlap with other disc metabolites and linearly depends on P. acnes concentration. Consequently, NMR spectroscopy may provide a noninvasive method to detect disc infection in the clinical setting. N/A.

  19. Axial Creep Loading and Unloaded Recovery of the Human Intervertebral Disc and the Effect of Degeneration

    Science.gov (United States)

    O'Connell, Grace D.; Jacobs, Nathan T.; Sen, Sounok; Vresilovic, Edward J.; Elliott, Dawn M.

    2011-01-01

    The intervertebral disc maintains a balance between externally applied loads and internal osmotic pressure. Fluid flow plays a key role in this process, causing fluctuations in disc hydration and height. The objectives of this study were to quantify and model the axial creep and recovery responses of nondegenerate and degenerate human lumbar discs. Two experiments were performed. First, a slow compressive ramp was applied to 2000 N, unloaded to allow recovery for up to 24 hours, and re-applied. The linear-region stiffness and disc height were within 5% of the initial condition for recovery times greater than 8 hours. In the second experiment, a 1000 N creep load was applied for four hours, unloaded recovery monitored for 24 hours, and the creep load repeated. A viscoelastic model comprised of a “fast” and “slow” exponential response was used to describe the creep and recovery, where the fast response is associated with flow in the nucleus pulposus (NP) and endplate, while the slow response is associated with the annulus fibrosus (AF). The study demonstrated that recovery is 3-4X slower than loading. The fast response was correlated with degeneration, suggesting larger changes in the NP with degeneration compared to the AF. However, the fast response comprised only 10-15% of the total equilibrium displacement, with the AF-dominated slow response comprising 40-70%. Finally, the physiological loads and deformations and their associated long equilibrium times confirm that diurnal loading does not represent “equilibrium” in the disc, but that over time the disc is in steady-state. PMID:21783103

  20. Degenerative spine disorders in the context of clinical findings

    International Nuclear Information System (INIS)

    Freund, Michael; Sartor, Klaus

    2006-01-01

    Hardly any other structure in the human body is held responsible for so many complaints, pain, and costs as the spine and its degenerative disorders. In the following article, the role of imaging procedures in diagnosing disorders of the spine is presented. Due to the fact that disk herniation represents the most frequent cause for degenerative disorders the anatomy of the intervertebral disk and the pathology of the entities that can cause diseases of the disks are described. In particular, the authors focus on the significance of radiological findings with respect to patient history, subjective symptoms, and objective clinical findings. In addition to presenting the technical procedures and their indications and contraindications also practical tips and tricks in conducting these examinations are presented in this paper

  1. Degenerative spine disorders in the context of clinical findings

    Energy Technology Data Exchange (ETDEWEB)

    Freund, Michael [Institut fuer Radiologie und Neuroradiologie, Klinikum Aschaffenburg, Am Hasenkopf 1, 63739 Aschaffenburg (Germany) and Abteilung fuer Neuroradiologie, Universitaetsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg (Germany)]. E-mail: michael.freund@klinikum-aschaffenburg.de; Sartor, Klaus [Abteilung fuer Neuroradiologie, Universitaetsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg (Germany)

    2006-04-15

    Hardly any other structure in the human body is held responsible for so many complaints, pain, and costs as the spine and its degenerative disorders. In the following article, the role of imaging procedures in diagnosing disorders of the spine is presented. Due to the fact that disk herniation represents the most frequent cause for degenerative disorders the anatomy of the intervertebral disk and the pathology of the entities that can cause diseases of the disks are described. In particular, the authors focus on the significance of radiological findings with respect to patient history, subjective symptoms, and objective clinical findings. In addition to presenting the technical procedures and their indications and contraindications also practical tips and tricks in conducting these examinations are presented in this paper.

  2. Can Exercise Positively Influence the Intervertebral Disc?

    Science.gov (United States)

    Belavý, Daniel L; Albracht, Kirsten; Bruggemann, Gert-Peter; Vergroesen, Pieter-Paul A; van Dieën, Jaap H

    2016-04-01

    To better understand what kinds of sports and exercise could be beneficial for the intervertebral disc (IVD), we performed a review to synthesise the literature on IVD adaptation with loading and exercise. The state of the literature did not permit a systematic review; therefore, we performed a narrative review. The majority of the available data come from cell or whole-disc loading models and animal exercise models. However, some studies have examined the impact of specific sports on IVD degeneration in humans and acute exercise on disc size. Based on the data available in the literature, loading types that are likely beneficial to the IVD are dynamic, axial, at slow to moderate movement speeds, and of a magnitude experienced in walking and jogging. Static loading, torsional loading, flexion with compression, rapid loading, high-impact loading and explosive tasks are likely detrimental for the IVD. Reduced physical activity and disuse appear to be detrimental for the IVD. We also consider the impact of genetics and the likelihood of a 'critical period' for the effect of exercise in IVD development. The current review summarises the literature to increase awareness amongst exercise, rehabilitation and ergonomic professionals regarding IVD health and provides recommendations on future directions in research.

  3. Combined Therapies of Modified Taiyi Miraculous Moxa Roll and Cupping for Patients with Lumbar Intervertebral Disc Herniation

    Directory of Open Access Journals (Sweden)

    Chunyue Cai

    2018-01-01

    Full Text Available Lumbar intervertebral disc herniation is a kind of syndrome caused by stimulation or pressure of nerve root and cauda equina due to intervertebral disc disorder, fibrous ring rupture, and pulpiform nucleus protrusion. Application of traditional Chinese medicine (TCM including acupuncture therapy and cupping therapy is unique and effective treatment for lumbar intervertebral disc herniation in China. Hence, we try to investigate the combined clinical efficacy of modified Taiyi miraculous moxa roll and cupping therapy on patients with lumbar intervertebral disc herniation. Seventy patients were randomly assigned into combined treatment group (n=35 and control group (n=35. The treatment group received combined therapy of modified Taiyi miraculous moxa roll and cupping therapy, while control group received acupuncture therapy alone. Diagnostic criteria of TCM syndrome, Japanese Orthopedic Association (JOA score, and simplified McGill pain questionnaire (MPQ were used to evaluate the therapy. 11 and 13 out of 35 subjects in the combined treatment group had improvement > 75% and between 50% and 75%, respectively. The corresponding number was 2 and 22 of 35 subjects in the acupuncture group. There was significant difference in the clinical efficacy between the treatment group and control group (P=0.036. The scores of JOA and MPQ detected in the patients of the two groups (P<0.05 also showed statistically significant differences. Moreover, no serious adverse events occurred in the patients, who received cupping therapy or acupuncture. The combined or alone therapies can effectively improve the treatment efficacy in the patients with lumbar intervertebral disc herniation, while the combined therapies show more comparative effectiveness. Furthermore, the combined therapies are potentially safe and cost-effective and also benefit the improvement of short-term pain. Therefore, the combined therapies of the two ancient TCM deserve further clinical

  4. ALMA Survey of Lupus Protoplanetary Disks. II. Gas Disk Radii

    Science.gov (United States)

    Ansdell, M.; Williams, J. P.; Trapman, L.; van Terwisga, S. E.; Facchini, S.; Manara, C. F.; van der Marel, N.; Miotello, A.; Tazzari, M.; Hogerheijde, M.; Guidi, G.; Testi, L.; van Dishoeck, E. F.

    2018-05-01

    We present Atacama Large Millimeter/Sub-Millimeter Array (ALMA) Band 6 observations of a complete sample of protoplanetary disks in the young (∼1–3 Myr) Lupus star-forming region, covering the 1.33 mm continuum and the 12CO, 13CO, and C18O J = 2–1 lines. The spatial resolution is ∼0.″25 with a medium 3σ continuum sensitivity of 0.30 mJy, corresponding to M dust ∼ 0.2 M ⊕. We apply Keplerian masking to enhance the signal-to-noise ratios of our 12CO zero-moment maps, enabling measurements of gas disk radii for 22 Lupus disks; we find that gas disks are universally larger than millimeter dust disks by a factor of two on average, likely due to a combination of the optically thick gas emission and the growth and inward drift of the dust. Using the gas disk radii, we calculate the dimensionless viscosity parameter, α visc, finding a broad distribution and no correlations with other disk or stellar parameters, suggesting that viscous processes have not yet established quasi-steady states in Lupus disks. By combining our 1.33 mm continuum fluxes with our previous 890 μm continuum observations, we also calculate the millimeter spectral index, α mm, for 70 Lupus disks; we find an anticorrelation between α mm and millimeter flux for low-mass disks (M dust ≲ 5), followed by a flattening as disks approach α mm ≈ 2, which could indicate faster grain growth in higher-mass disks, but may also reflect their larger optically thick components. In sum, this work demonstrates the continuous stream of new insights into disk evolution and planet formation that can be gleaned from unbiased ALMA disk surveys.

  5. Association between intervertebral disc degeneration and the Oswestry Disability Index.

    Science.gov (United States)

    Middendorp, Marcus; Vogl, Thomas J; Kollias, Konstantinos; Kafchitsas, Konstantinos; Khan, M Fawad; Maataoui, Adel

    2017-01-01

    Low back pain and lumbar intervertebral disc degeneration (IDD) are common findings. Valid data on correlation between clinical pain scores and grades of IDD are not available. To investigate the correlation of intervertebral disc degeneration (IDD) at lumbar levels L4/5 and L5/S1 and the Oswestry Disability Index (ODI). The lumbar discs L4/5 and L5/S1 of 591 patients were evaluated according to the 5-point (Grade I to Grade V) grading system as published by Pfirrmann et al. Functional status was assessed using the Oswestry Disability Index. Spearman's coefficient of rank correlation was used for statistical analysis (p disability (ODI score between 21 and 40%). There was a weak, but statistically significant positive correlation between IDD and ODI for both evaluated lumbar levels. Increased lumbar IDD in MRI goes along with an increased ODI. Thus, MRI is a strong indicator of a patient's clinical appearance. However, low back pain cannot be explained by imaging alone. Clinical correlation is imperative for an adequate diagnostic advance in patients with low back pain.

  6. Calcification of intervertebral discs in the Dachshund: An estimation of heritability

    Energy Technology Data Exchange (ETDEWEB)

    Stigen, Ø. [Norges Veterinaerhoegskole, Oslo (Norway); Christensen, K.

    1993-07-01

    The heritability of calcified intervertebral discs in the dachshund was estimated using data gathered from a radiographic study. Radiographs of the vertebral columns of 274 clinically normal, 12 to 18 months old dachshunds, were examined. The dogs were offspring from 75 different sires, representing the same number of half sib groups. There were 2 to 14 offspring in each half-sib group. The number of full sib groups was 81. Calcified intervertebral discs were identified in 20.4% of the dogs. An analysis of variance that used the data as a continuous and as an either/or-variable estimated the heritability of calcified discs to be 0.22 and 0.15 respectively. A genetic factor was found to be essential for the occurrence of calcified discs in a dog while a common environmental factor presumably resulting from non-genetic causes was significant in determining the number of discs to undergo calcification in affected dogs.

  7. THICK-DISK EVOLUTION INDUCED BY THE GROWTH OF AN EMBEDDED THIN DISK

    International Nuclear Information System (INIS)

    Villalobos, Alvaro; Helmi, Amina; Kazantzidis, Stelios

    2010-01-01

    We perform collisionless N-body simulations to investigate the evolution of the structural and kinematical properties of simulated thick disks induced by the growth of an embedded thin disk. The thick disks used in the present study originate from cosmologically common 5:1 encounters between initially thin primary disk galaxies and infalling satellites. The growing thin disks are modeled as static gravitational potentials and we explore a variety of growing-disk parameters that are likely to influence the response of thick disks. We find that the final thick-disk properties depend strongly on the total mass and radial scale length of the growing thin disk, and much less sensitively on its growth timescale and vertical scale height as well as the initial sense of thick-disk rotation. Overall, the growth of an embedded thin disk can cause a substantial contraction in both the radial and vertical direction, resulting in a significant decrease in the scale lengths and scale heights of thick disks. Kinematically, a growing thin disk can induce a notable increase in the mean rotation and velocity dispersions of thick-disk stars. We conclude that the reformation of a thin disk via gas accretion may play a significant role in setting the structure and kinematics of thick disks, and thus it is an important ingredient in models of thick-disk formation.

  8. Qualitative and quantitative assessment of collagen and elastin in annulus fibrosus of the physiologic and scoliotic intervertebral discs.

    Science.gov (United States)

    Kobielarz, Magdalena; Szotek, Sylwia; Głowacki, Maciej; Dawidowicz, Joanna; Pezowicz, Celina

    2016-09-01

    The biophysical properties of the annulus fibrosus of the intervertebral disc are determined by collagen and elastin fibres. The progression of scoliosis is accompanied by a number of pathological changes concerning these structural proteins. This is a major cause of dysfunction of the intervertebral disc. The object of the study were annulus fibrosus samples excised from intervertebral discs of healthy subjects and patients treated surgically for scoliosis in the thoracolumbar or lumbar spine. The research material was subjected to structural analysis by light microscopy and quantitative analysis of the content of collagen types I, II, III and IV as well as elastin by immunoenzymatic test (ELISA). A statistical analysis was conducted to assess the impact of the sampling site (Mann-Whitney test, α=0.05) and scoliosis (Wilcoxon matched pairs test, α=0.05) on the obtained results. The microscopic studies conducted on scoliotic annulus fibrosus showed a significant architectural distortion of collagen and elastin fibres. Quantitative biochemical assays demonstrated region-dependent distribution of only collagen types I and II in the case of healthy intervertebral discs whereas in the case of scoliotic discs region-dependent distribution concerned all examined proteins of the extracellular matrix. Comparison of scoliotic and healthy annulus fibrosus revealed a significant decrease in the content of collagen type I and elastin as well as a slight increase in the proportion of collagen types III and IV. The content of collagen type II did not differ significantly between both groups. The observed anomalies are a manifestation of degenerative changes affecting annulus fibrosus of the intervertebral disc in patients suffering from scoliosis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Heme oxygenase-1 modulates degeneration of the intervertebral disc after puncture in Bach 1 deficient mice.

    Science.gov (United States)

    Ohta, Ryo; Tanaka, Nobuhiro; Nakanishi, Kazuyoshi; Kamei, Naosuke; Nakamae, Toshio; Izumi, Bunichiro; Fujioka, Yuki; Ochi, Mitsuo

    2012-09-01

    Intervertebral disc degeneration is considered to be a major feature of low back pain. Furthermore, oxidative stress has been shown to be an important factor in degenerative diseases such as osteoarthritis and is considered a cause of intervertebral disc degeneration. The purpose of this study was to clarify the correlation between oxidative stress and intervertebral disc degeneration using Broad complex-Tramtrack-Bric-a-brac and cap'n'collar homology 1 deficient (Bach 1-/-) mice which highly express heme oxygenase-1 (HO-1). HO-1 protects cells from oxidative stress. Caudal discs of 12-week-old and 1-year-old mice were evaluated as age-related models. Each group and period, 5 mice (a total of 20 mice, a total of 20 discs) were evaluated as age-related model. C9-C10 caudal discs in 12-week-old Bach 1-/- and wild-type mice were punctured using a 29-gauge needle as annulus puncture model. Each group and period, 5 mice (a total of 60 mice, a total of 60 discs) were evaluated. The progress of disc degeneration was evaluated at pre-puncture, 1, 2, 4, 8 and 12 weeks post-puncture. Radiographic, histologic and immunohistologic analysis were performed to compare between Bach 1-/- and wild-type mice. In the age-related model, there were no significant differences between Bach 1-/- and wild-type mice radiologically and histologically. However, in the annulus puncture model, histological scoring revealed significant difference at 8 and 12 weeks post-puncture. The number of HO-1 positive cells was significantly greater in Bach 1-/- mice at every period. The apoptosis rate was significantly lower at 1 and 2 weeks post-puncture in Bach 1-/- mice. Oxidative stress prevention may avoid the degenerative process of the intervertebral disc after puncture, reducing the number of apoptosis cells. High HO-1 expression may also inhibit oxidative stress and delay the process of intervertebral disc degeneration.

  10. Matrix Remodeling During Intervertebral Disc Growth and Degeneration Detected by Multichromatic FAST Staining

    Science.gov (United States)

    Leung, Victor Y.L.; Chan, Wilson C.W.; Hung, Siu-Chun; Cheung, Kenneth M.C.; Chan, Danny

    2009-01-01

    Various imaging techniques have been used to assess degeneration of the intervertebral disc, including many histological methods, but cartilage-oriented histological stains do not clearly show the comparatively complex structures of the disc. In addition, there is no integrated method to assess efficiently both the compartmental organization and matrix composition in disc samples. In this study, a novel histological method, termed FAST staining, has been developed to investigate disc growth and degeneration by sequential staining with fast green, Alcian blue, Safranin-O, and tartrazine to generate multichromatic histological profiles (FAST profiles). This identifies the major compartments of the vertebra-disc region, including the cartilaginous endplate and multiple zones of the annulus fibrosus, by specific FAST profile patterns. A disc degeneration model in rabbit established using a previously described puncture method showed gradual but profound alteration of the FAST profile during disc degeneration, supporting continual alteration of glycosaminoglycan. Changes of the FAST profile pattern in the nucleus pulposus and annulus fibrosus of the postnatal mouse spine suggested matrix remodeling activity during the growth of intervertebral discs. In summary, we developed an effective staining method capable of defining intervertebral disc compartments in detail and showing matrix remodeling events within the disc. The FAST staining method may be used to develop a histopathological grading system to evaluate disc degeneration or malformation. (J Histochem Cytochem 57:249–256, 2009) PMID:19001641

  11. Mechanical design criteria for intervertebral disc tissue engineering.

    Science.gov (United States)

    Nerurkar, Nandan L; Elliott, Dawn M; Mauck, Robert L

    2010-04-19

    Due to the inability of current clinical practices to restore function to degenerated intervertebral discs, the arena of disc tissue engineering has received substantial attention in recent years. Despite tremendous growth and progress in this field, translation to clinical implementation has been hindered by a lack of well-defined functional benchmarks. Because successful replacement of the disc is contingent upon replication of some or all of its complex mechanical behaviors, it is critically important that disc mechanics be well characterized in order to establish discrete functional goals for tissue engineering. In this review, the key functional signatures of the intervertebral disc are discussed and used to propose a series of native tissue benchmarks to guide the development of engineered replacement tissues. These benchmarks include measures of mechanical function under tensile, compressive, and shear deformations for the disc and its substructures. In some cases, important functional measures are identified that have yet to be measured in the native tissue. Ultimately, native tissue benchmark values are compared to measurements that have been made on engineered disc tissues, identifying where functional equivalence was achieved, and where there remain opportunities for advancement. Several excellent reviews exist regarding disc composition and structure, as well as recent tissue engineering strategies; therefore this review will remain focused on the functional aspects of disc tissue engineering. Copyright 2009 Elsevier Ltd. All rights reserved.

  12. Oscillations of disks

    CERN Document Server

    Kato, Shoji

    2016-01-01

    This book presents the current state of research on disk oscillation theory, focusing on relativistic disks and tidally deformed disks. Since the launch of the Rossi X-ray Timing Explorer (RXTE) in 1996, many high-frequency quasiperiodic oscillations (HFQPOs) have been observed in X-ray binaries. Subsequently, similar quasi-periodic oscillations have been found in such relativistic objects as microquasars, ultra-luminous X-ray sources, and galactic nuclei. One of the most promising explanations of their origin is based on oscillations in relativistic disks, and a new field called discoseismology is currently developing. After reviewing observational aspects, the book presents the basic characteristics of disk oscillations, especially focusing on those in relativistic disks. Relativistic disks are essentially different from Newtonian disks in terms of several basic characteristics of their disk oscillations, including the radial distributions of epicyclic frequencies. In order to understand the basic processes...

  13. Continuous lumbar hemilaminectomy for intervertebral disc disease in an Amur tiger (Panthera tigris altaica).

    Science.gov (United States)

    Flegel, Thomas; Böttcher, Peter; Alef, Michaele; Kiefer, Ingmar; Ludewig, Eberhard; Thielebein, Jens; Grevel, Vera

    2008-09-01

    A 13-yr-old Amur tiger (Panthera tigris altaica) was presented for an acute onset of paraplegia. Spinal imaging that included plain radiographs, myelography, and computed tomography performed under general anesthesia revealed lateralized spinal cord compression at the intervertebral disc space L4-5 caused by intervertebral disc extrusion. This extrusion was accompanied by an extensive epidural hemorrhage from L3 to L6. Therefore, a continuous hemilaminectomy from L3 to L6 was performed, resulting in complete decompression of the spinal cord. The tiger was ambulatory again 10 days after the surgery. This case suggests that the potential benefit of complete spinal cord decompression may outweigh the risk of causing clinically significant spinal instability after extensive decompression.

  14. The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs

    OpenAIRE

    Taylor, Michael P; Wedel, Mathew J.

    2013-01-01

    The necks of sauropod dinosaurs were a key factor in their evolution. The habitual posture and range of motion of these necks has been controversial, and computer-aided studies have argued for an obligatory sub-horizontal pose. However, such studies are compromised by their failure to take into account the important role of intervertebral cartilage. This cartilage takes very different forms in different animals. Mammals and crocodilians have intervertebral discs, while birds have synovial joi...

  15. Treatment of intervertebral disc degenerative disease using percutaneous nucleotomy–an overview of less invasive procedures

    Directory of Open Access Journals (Sweden)

    Miran Jeromel

    2014-04-01

    Full Text Available Background: Less invasive treatment methods for intervertebral disc disease and decompression of neural structures as a consequence of contained disc herniation represent an alternative to surgical procedure. Percutaneus nucleotomy uses a percutaneous approach to the intervertebral disc. The article presents the evolution of numerous procedureds in clinical practice.Methods: Percutaneous nucleoplasty is a fluoroscopy-guided procedure which enables controlled and safe entrance into the intervertebral disc. The procedure is performed under strict aseptic conditions, using a local anaesthesia with the patient under analgosedation. Based on the principle of therapeutic intradiscal action, the procedures can be divided into three groups: chemical (chemonucleolysis with chimopapain, alcohol, ozone, mechanical (automated percutaneous lumbar discectomy – APLD, arthroscopic discectomy and thermical methods (laser, radiofrequency ablation, intradiscal electrothermal annuloplasty – IDET, Coblation®.Results: Percutaneous nucleotomy by the majority of the mentioned procedures results in a therapeutic effect (reduction of pain and decompression of neural structures. Fast recovery represents a major advantage of less invasive treatment.Conclusions: Less invasive method (nucleotomy using different procedures represents a successful alternative approach to surgical discectomy. Proper patient selection and safe technique are mandatory in order to achieve a good clinical outcome.

  16. Quantitative evaluation of degenerative lumbar intervertebral disc applying an equivalent cross-relaxation rate using MRI

    International Nuclear Information System (INIS)

    Obata, Hideaki; Inaba, Tadashi; Kato, Takaya; Tokuda, Masataka; Matsushima, Shigeru; Yamada, Michiaki; Kinosada, Yasutomi

    2004-01-01

    The equivalent cross-relaxation rate (ECR) is a measurement method to evaluate a change in organizational structure quantitatively utilizing MRI. The objectives of this study are to understand the characteristics related to water contents in degenerative lumbar intervertebral discs, and to investigate the usefulness of quantitative evaluation using ECR in order to find as early as possible disordered discs. Seven normal volunteers and four asymptomatic volunteers with degeneration in lumbar intervertebral discs, 21 to 26 years of age, were studied using a SIGNA model of GE Medical Systems equipped with a 1.5 T clinical scanner and spine coil. The ECR values were defined as the percentage of signal loss between unsaturated and saturated images. The results showed that the ECR value of annulus fibrosus in an intervertebral disc was higher than nucleus pulposus. Furthermore, it was found that the ECR value of nucleus pulposus (L5-S1) with degeneration was significantly higher than that without degeneration. It was considered that this result reflected an increase of water contents in the degenerative nucleus. This study suggests that the ECR value of a nucleus could be an effective parameter to diagnosis of degenerated discs or grades of disorder. (author)

  17. Formation, function, and exhaustion of notochordal cytoplasmic vacuoles within intervertebral disc: current understanding and speculation

    Science.gov (United States)

    Sinkemani, Arjun; Xie, Zhi-Yang; Shi, Rui; Wei, Ji-Nan; Wu, Xiao-Tao

    2017-01-01

    Notochord nucleus pulposus cells are characteristic of containing abundant and giant cytoplasmic vacuoles. This review explores the embryonic formation, biological function, and postnatal exhaustion of notochord vacuoles, aiming to characterize the signal network transforming the vacuolated nucleus pulposus cells into the vacuole-less chondrocytic cells. Embryonically, the cytoplasmic vacuoles within vertebrate notochord originate from an evolutionarily conserved vacuolation process during neurulation, which may continue to provide mechanical and signal support in constructing a mammalian intervertebral disc. For full vacuolation, a vacuolating specification from dorsal organizer cells, synchronized convergent extension, well-structured notochord sheath, and sufficient post-Golgi trafficking in notochord cells are required. Postnatally, age-related and species-specific exhaustion of vacuolated nucleus pulposus cells could be potentiated by Fas- and Fas ligand-induced apoptosis, intolerance to mechanical stress and nutrient deficiency, vacuole-mediated proliferation check, and gradual de-vacuolation within the avascular and compression-loaded intervertebral disc. These results suggest that the notochord vacuoles are active and versatile organelles for both embryonic notochord and postnatal nucleus pulposus, and may provide novel information on intervertebral disc degeneration to guide cell-based regeneration. PMID:28915712

  18. Magnetically Induced Disk Winds and Transport in the HL Tau Disk

    International Nuclear Information System (INIS)

    Hasegawa, Yasuhiro; Flock, Mario; Turner, Neal J.; Okuzumi, Satoshi

    2017-01-01

    The mechanism of angular momentum transport in protoplanetary disks is fundamental to understanding the distributions of gas and dust in the disks. The unprecedented ALMA observations taken toward HL Tau at high spatial resolution and subsequent radiative transfer modeling reveal that a high degree of dust settling is currently achieved in the outer part of the HL Tau disk. Previous observations, however, suggest a high disk accretion rate onto the central star. This configuration is not necessarily intuitive in the framework of the conventional viscous disk model, since efficient accretion generally requires a high level of turbulence, which can suppress dust settling considerably. We develop a simplified, semi-analytical disk model to examine under what condition these two properties can be realized in a single model. Recent, non-ideal MHD simulations are utilized to realistically model the angular momentum transport both radially via MHD turbulence and vertically via magnetically induced disk winds. We find that the HL Tau disk configuration can be reproduced well when disk winds are properly taken into account. While the resulting disk properties are likely consistent with other observational results, such an ideal situation can be established only if the plasma β at the disk midplane is β 0 ≃ 2 × 10 4 under the assumption of steady accretion. Equivalently, the vertical magnetic flux at 100 au is about 0.2 mG. More detailed modeling is needed to fully identify the origin of the disk accretion and quantitatively examine plausible mechanisms behind the observed gap structures in the HL Tau disk.

  19. Magnetically Induced Disk Winds and Transport in the HL Tau Disk

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Yasuhiro; Flock, Mario; Turner, Neal J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Okuzumi, Satoshi, E-mail: yasuhiro@caltech.edu [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan)

    2017-08-10

    The mechanism of angular momentum transport in protoplanetary disks is fundamental to understanding the distributions of gas and dust in the disks. The unprecedented ALMA observations taken toward HL Tau at high spatial resolution and subsequent radiative transfer modeling reveal that a high degree of dust settling is currently achieved in the outer part of the HL Tau disk. Previous observations, however, suggest a high disk accretion rate onto the central star. This configuration is not necessarily intuitive in the framework of the conventional viscous disk model, since efficient accretion generally requires a high level of turbulence, which can suppress dust settling considerably. We develop a simplified, semi-analytical disk model to examine under what condition these two properties can be realized in a single model. Recent, non-ideal MHD simulations are utilized to realistically model the angular momentum transport both radially via MHD turbulence and vertically via magnetically induced disk winds. We find that the HL Tau disk configuration can be reproduced well when disk winds are properly taken into account. While the resulting disk properties are likely consistent with other observational results, such an ideal situation can be established only if the plasma β at the disk midplane is β {sub 0} ≃ 2 × 10{sup 4} under the assumption of steady accretion. Equivalently, the vertical magnetic flux at 100 au is about 0.2 mG. More detailed modeling is needed to fully identify the origin of the disk accretion and quantitatively examine plausible mechanisms behind the observed gap structures in the HL Tau disk.

  20. Magnetic Resonance Imaging Follow-up Study on Two Cases of Lumbar intervertebral Disc Sequestration Patients Treated with Oriental Medicine Treatment

    Directory of Open Access Journals (Sweden)

    Ki-Su Lee

    2011-09-01

    Full Text Available Objectives: The purpose of this study is to report the image changes of two cases of Lumbar intervertebral Disc Sequestration after oriental medical treatment. Methods: We examined 2 patients with Lumbar intervertebral Disc Sequestration who showed changes on MRI images before/after the treatment. And we assessed clinical symptoms by using numeric rating scale(NRS and straight leg raising test(SLRT. Results & Conclusions : In this study, the first MRI examination of Lumbar intervertebral Disc Sequestration patients was performed at the first visit and re-examination of MRI was done after treatment. In each case, the size of the disc sequestration was considerably reduced in MRI image. And both patients represented effective improvment in NRS score and SLRT test angle.

  1. Evaluation of apoptotic cell death in normal and chondrodystrophic canine intervertebral discs

    Directory of Open Access Journals (Sweden)

    Marie Klauser

    2012-02-01

    Full Text Available Disc degeneration occurs commonly in dogs. A variety of factors is thought to contribute an inappropriate disc matrix that isolate cells in the disc and lead to apoptosis. Disc herniation with radiculopathy and discogenic pain are the results of the degenerative process. The objective of this prospective study was to determine the extent of apoptosis in intact and herniated intervertebral discs of chondrodystrophic dogs and non-chondrodystrophic dogs. In addition, the nucleus pulposus (NP was histologically compared between non-chondrodystrophic and chondrodystrophic dogs. Thoracolumbar intervertebral discs and parts of the extruded nucleus pulposus were harvested from 45 dogs. Samples were subsequently stained with haematoxylin-eosin and processed to detect cleaved caspase-3 and poly(ADP-ribose polymerase. A significant greater degree of apoptosis was observed in herniated NPs of chondrodystrophic dogs compared to non- chondrodystrophic dogs with poly (ADP-ribose polymerase and cleaved caspase- 3 detection. Within the group of chondrodystrophic dogs, dogs with an intact disc and younger than 6 years showed a significant lower incidence of apoptosis in the NP compared to the herniated NP of chondrodystrophic dogs. The extent of apoptosis in the annulus fibrosus was not different between the intact disc from chondrodystrophic and non- chondrodystrophic dogs. An age-related increase of apoptotic cells in NP and annulus fibrosus was found in the intact non-herniated intervertebral discs. Histologically, absence of notochordal cells and occurrence of chondroid metaplasia were observed in the nucleus pulposus of chondrodystrophic dogs. As a result, we found that apoptosis plays a role in disc degeneration in chondrodystrophic dogs.

  2. Mechanical restoration and failure analyses of a hydrogel and scaffold composite strategy for annulus fibrosus repair

    NARCIS (Netherlands)

    Long, R.G.; Bürki, A.; Zysset, P.; Eglin, D.; Grijpma, Dirk W.; Blanquer, Sebastien; Hecht, A.C.; Iatridis, J.C.

    2016-01-01

    Unrepaired defects in the annulus fibrosus of intervertebral disks are associated with degeneration and persistent back pain. A clinical need exists for a disk repair strategy that can seal annular defects, be easily delivered during surgical procedures, and restore biomechanics with low risk of

  3. Development of poly(trimethylene carbonate) network implants for annulus fibrosus tissue engineering

    NARCIS (Netherlands)

    Blanquer, Sebastien; Sharifi, Shahriar; Grijpma, Dirk W.

    2012-01-01

    Purpose: Intervertebral disk degeneration is the main cause of chronic back pain. Disk degeneration often leads to tearing of the annulus fibrosus (AF) and extrusion of the nucleus pulposus (NP), which compresses the nerves. Current treatment involves removing the herniated NP and suturing the

  4. Association between CT-evaluated lumbar lordosis and features of spinal degeneration, evaluated in supine position

    Science.gov (United States)

    Kalichman, Leonid; Li, Ling; Hunter, David; Been, Ella

    2013-01-01

    Background Context Few studies have directly evaluated the association of lumbar lordosis and segmental wedging of the vertebral bodies and intervertebral disks with prevalence of spinal degenerative features. Purpose To evaluate the association of CT-evaluated lumbar lordosis, segmental wedging of the vertebral bodies and that of the intervertebral disks with various spinal degeneration features. Study design This cross-sectional study was a nested project to the Framingham Heart Study. Sample A random consecutive subset of 191 participants chosen from the 3590 participants enrolled in the Framingham Heart Study who underwent multi-detector CT to assess aortic calcification. Outcome Measures Physiologic Measures Dichotomous variables indicating the presence of intervertebral disc narrowing, facet joint osteoarthritis, spondylolysis, spondylolisthesis and spinal stenosis and density (in Hounsfield units) of multifidus and erector spinae muscles were evaluated on supine CT, as well as the lordosis angle (LA) and the wedging of the vertebral bodies and intervertebral disks. Sum of vertebral bodies wedging (ΣB) and sum of intervertebral discs wedging (ΣD) were used in analyses. Methods Mean values (±SD) of LA, ΣB and ΣD were calculated in males and females and compared using the t-test. Mean values (±SD) of LA, ΣB and ΣD in 4 age groups: 0.05) with increasing age. LA showed statistically significant association with presence of spondylolysis (OR(95%CI): 1.08(1.02–1.14)) and with density of multifidus (1.06 (1.01–1.11). as well as a marginally significant association with isthmic spondylolisthesis (1.07(1.00–1.14). ΣB showed a positive association with degenerative spondylolisthesis and disc narrowing ((1.14(1.06–1.23) and 1.04 (1.00–1.08), correspondingly), whereas ΣD showed negative one (0.93(0.87–0.98) and (0.93(0.89–0.97), correspondingly). Conclusions Significant associations were found between lumbar lordosis evaluated in supine position

  5. Follow-up radiographs of the cervical spine after anterior fusion with titanium intervertebral disc

    International Nuclear Information System (INIS)

    Biederer, J.; Hutzelmann, A.; Heller, M.; Rama, B.

    1999-01-01

    Purpose: We examined the postoperative changes of the cervical spine after treatment of cervical nerve root compression with anterior cervical discectomy and fusion with a new titanium intervertebral disc. Patients and Methods: 37 patients were examined prior to, as well as 4 days, 6 weeks, and 7 months after surgery. Lateral view X-rays and functional imaging were used to evaluate posture and mobility of the cervical spine, the position of the implants, and the reactions of adjacent bone structures. Results: Implantation of the titanium disc led to post-operative distraction of the intervertebral space and slight lordosis. Within the first 6 months a slight loss of distraction and re-kyphosis due to impression of the implants into the vertebral end-plates were found in all patients. We noted partial infractions into the vertebral end-plates in 10/42 segments and slight mobility of the implants in 14/42 segments. Both groups of patients showed reactive spondylosis and local symptoms due to loosening of the implants. The pain subsided after onset of bone bridging and stable fixation of the loosened discs. Conclusions: The titanium intervertebral disc provides initial distraction of the fusioned segments with partial recurrence of kyphosis during the subsequent course. Loosening of the implants with local symptoms can be evaluated with follow-up X-rays and functional imaging. (orig.) [de

  6. Contact statuses between functionally graded brake disk and pure pad disk

    International Nuclear Information System (INIS)

    Shahzamanian, M.M.; Sahari, B.B.; Bayat, M.; Mustapha, F.; Ismarrubie, Z.N.; Shahrjerdi, A.

    2009-01-01

    Full text: The contact statuses between functionally graded (FG) brake disks and pure pad disk are investigated by using finite element method (FEM). Two types of variation is considered for FG brake disk, the variation of materials are considered change in radial and thickness direction of disk. The material properties of these two types of FG brake disks are assumed to be represented by power-law distributions in the radius and thickness direction. The results are obtained and then compared. For the radial FG brake disk, the inner and outer surfaces are considered metal and ceramic respectively, and friction coefficient between metal surface and ceramic surface of FG brake dick with pad are considered 1.4 and 0.75 respectively. For the thickness FG brake disk the contact surface with pure pad brake disk is ceramic and the free surface is metal and friction coefficient between ceramic (contact) surface and pure pad brake disk is considered 0.75. In both types of FG brake disks the Coulomb contact friction is applied. Mechanical response of FG brake disks are compared and verified with the known results in the literatures. Three types of contact statuses are introduced as Sticking, Contact and Near Contact. The contact status between pad and disk for different values for pad thickness, grading index,n , and percentage of friction coefficient (λ) is shown. It can be seen that for all values of percentage of friction coefficient,λ , and grading indices, n, by increasing the thickness of pad cause the contact status changes from sticking to contact and then to near contact. (author)

  7. GIANT PLANET MIGRATION, DISK EVOLUTION, AND THE ORIGIN OF TRANSITIONAL DISKS

    International Nuclear Information System (INIS)

    Alexander, Richard D.; Armitage, Philip J.

    2009-01-01

    We present models of giant planet migration in evolving protoplanetary disks. Our disks evolve subject to viscous transport of angular momentum and photoevaporation, while planets undergo Type II migration. We use a Monte Carlo approach, running large numbers of models with a range in initial conditions. We find that relatively simple models can reproduce both the observed radial distribution of extrasolar giant planets, and the lifetimes and accretion histories of protoplanetary disks. The use of state-of-the-art photoevaporation models results in a degree of coupling between planet formation and disk clearing, which has not been found previously. Some accretion across planetary orbits is necessary if planets are to survive at radii ∼<1.5 AU, and if planets of Jupiter mass or greater are to survive in our models they must be able to form at late times, when the disk surface density in the formation region is low. Our model forms two different types of 'transitional' disks, embedded planets and clearing disks, which show markedly different properties. We find that the observable properties of these systems are broadly consistent with current observations, and highlight useful observational diagnostics. We predict that young transition disks are more likely to contain embedded giant planets, while older transition disks are more likely to be undergoing disk clearing.

  8. Diskitis

    Science.gov (United States)

    ... a Medical Professional Call your provider if your child has back pain that does not go away, or problems with standing and walking that seem unusual for his or her age. Alternative Names Disk inflammation Images Skeletal spine Intervertebral disk References Gutierrez K. Diskitis. In: Long SS, ...

  9. Proportional lumbar spine inter-vertebral motion patterns: a comparison of patients with chronic, non-specific low back pain and healthy controls

    OpenAIRE

    Mellor, Fiona E.; Thomas, Peter; Thompson, Paul W.; Breen, Alan C.

    2014-01-01

    Introduction: Identifying biomechanical subgroups in chronic, non-specific low back pain (CNSLBP) populations from inter-vertebral displacements has proven elusive. Quantitative fluoroscopy (QF) has excellent repeatability and provides continuous standardised inter-vertebral kinematic data from fluoroscopic sequences allowing assessment of mid-range motion. The aim of this study was to determine whether proportional continuous IV rotational patterns were different in patients and controls. A ...

  10. Disk Storage Server

    CERN Multimedia

    This model was a disk storage server used in the Data Centre up until 2012. Each tray contains a hard disk drive (see the 5TB hard disk drive on the main disk display section - this actually fits into one of the trays). There are 16 trays in all per server. There are hundreds of these servers mounted on racks in the Data Centre, as can be seen.

  11. HNC IN PROTOPLANETARY DISKS

    International Nuclear Information System (INIS)

    Graninger, Dawn; Öberg, Karin I.; Qi, Chunhua; Kastner, Joel

    2015-01-01

    The distributions and abundances of small organics in protoplanetary disks are potentially powerful probes of disk physics and chemistry. HNC is a common probe of dense interstellar regions and the target of this study. We use the Submillimeter Array (SMA) to observe HNC 3–2 toward the protoplanetary disks around the T Tauri star TW Hya and the Herbig Ae star HD 163296. HNC is detected toward both disks, constituting the first spatially resolved observations of HNC in disks. We also present SMA observations of HCN 3–2 and IRAM 30 m observations of HCN and HNC 1–0 toward HD 163296. The disk-averaged HNC/HCN emission ratio is 0.1–0.2 toward both disks. Toward TW Hya, the HNC emission is confined to a ring. The varying HNC abundance in the TW Hya disk demonstrates that HNC chemistry is strongly linked to the disk physical structure. In particular, the inner rim of the HNC ring can be explained by efficient destruction of HNC at elevated temperatures, similar to what is observed in the ISM. However, to realize the full potential of HNC as a disk tracer requires a combination of high SNR spatially resolved observations of HNC and HCN and disk-specific HNC chemical modeling

  12. HNC IN PROTOPLANETARY DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Graninger, Dawn; Öberg, Karin I.; Qi, Chunhua [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kastner, Joel, E-mail: dgraninger@cfa.harvard.edu [Center for Imaging Science, School of Physics and Astronomy, and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States)

    2015-07-01

    The distributions and abundances of small organics in protoplanetary disks are potentially powerful probes of disk physics and chemistry. HNC is a common probe of dense interstellar regions and the target of this study. We use the Submillimeter Array (SMA) to observe HNC 3–2 toward the protoplanetary disks around the T Tauri star TW Hya and the Herbig Ae star HD 163296. HNC is detected toward both disks, constituting the first spatially resolved observations of HNC in disks. We also present SMA observations of HCN 3–2 and IRAM 30 m observations of HCN and HNC 1–0 toward HD 163296. The disk-averaged HNC/HCN emission ratio is 0.1–0.2 toward both disks. Toward TW Hya, the HNC emission is confined to a ring. The varying HNC abundance in the TW Hya disk demonstrates that HNC chemistry is strongly linked to the disk physical structure. In particular, the inner rim of the HNC ring can be explained by efficient destruction of HNC at elevated temperatures, similar to what is observed in the ISM. However, to realize the full potential of HNC as a disk tracer requires a combination of high SNR spatially resolved observations of HNC and HCN and disk-specific HNC chemical modeling.

  13. Relationships between lumbar inter-vertebral motion and lordosis in healthy adult males: a cross sectional cohort study.

    Science.gov (United States)

    du Rose, Alister; Breen, Alan

    2016-03-10

    Intervertebral motion impairment is widely thought to be related to chronic back disability, however, the movements of inter-vertebral pairs are not independent of each other and motion may also be related to morphology. Furthermore, maximum intervertebral range of motion (IV-RoMmax) is difficult to measure accurately in living subjects. The purpose of this study was to explore possible relationships between (IV-RoMmax) and lordosis, initial attainment rate and IV-RoMmax at other levels during weight-bearing flexion using quantitative fluoroscopy (QF). Continuous QF motion sequences were recorded during controlled active sagittal flexion of 60° in 18 males (mean age 27.6 SD 4.4) with no history of low back pain in the previous year. IV-RoMmax, lordotic angle, and initial attainment rate at all inter-vertebral levels from L2-S1 were extracted. Relationships between IV-RoMmax and the other variables were explored using correlation coefficients, and simple linear regression was used to determine the effects of any significant relationships. Within and between observer repeatability of IV-RoMmax and initial attainment rate measurements were assessed in a sub-set of ten participants, using the intra-class correlation coefficient (ICC) and standard error of measurement (SEM). QF measurements were highly repeatable, the lowest ICC for IV-RoMmax, being 0.94 (0.80-0.99) and highest SEM (0.76°). For initial attainment rate the lowest ICC was 0.84 (0.49-0.96) and the highest SEM (0.036). The results also demonstrated significant positive and negative correlations between IV-RoMmax and IV-RoMmax at other lumbar levels (r = -0.64-0.65), lordosis (r = -0.52-0.54), and initial attainment rate (r = -0.64-0.73). Simple linear regression analysis of all significant relationships showed that these predict between 28 and 42 % of the variance in IV-RoMmax. This study found weak to moderate effects of individual kinematic variables and lumbar lordosis on IV-RoMmax at

  14. Intercellular signaling pathways active during intervertebral disc growth, differentiation, and aging.

    Science.gov (United States)

    Dahia, Chitra Lekha; Mahoney, Eric J; Durrani, Atiq A; Wylie, Christopher

    2009-03-01

    Intervertebral discs at different postnatal ages were assessed for active intercellular signaling pathways. To generate a spatial and temporal map of the signaling pathways active in the postnatal intervertebral disc (IVD). The postnatal IVD is a complex structure, consisting of 3 histologically distinct components, the nucleus pulposus, fibrous anulus fibrosus, and endplate. These differentiate and grow during the first 9 weeks of age in the mouse. Identification of the major signaling pathways active during and after the growth and differentiation period will allow functional analysis using mouse genetics and identify targets for therapy for individual components of the disc. Antibodies specific for individual cell signaling pathways were used on cryostat sections of IVD at different postnatal ages to identify which components of the IVD were responding to major classes of intercellular signal, including sonic hedgehog, Wnt, TGFbeta, FGF, and BMPs. We present a spatial/temporal map of these signaling pathways during growth, differentiation, and aging of the disc. During growth and differentiation of the disc, its different components respond at different times to different intercellular signaling ligands. Most of these are dramatically downregulated at the end of disc growth.

  15. Development of Disk Rover, wall-climbing robot using permanent magnet disk

    International Nuclear Information System (INIS)

    Hirose, Shigeo; Tsutsumitake; Hiroshi; Toyama, Ryousei; Kobayashi, Kengo.

    1992-01-01

    A new type of wall climbing robot, named Disk Rover, using permanent magnet disks are developed. The newly introduced permanent magnet disk is to rotate the magnet disk on the surface of wall with partly contacted posture. It allows to produce high magnetic attraction force compared with conventional permanent wheel which utilizes only a small portion of the magnet installed around the wheel. The optimum design of the magnetic wheel is done by using finit element method and it is shown that the magnetic attraction force vs. weight ratio can be designed about three times higher than conventional type magnet wheel. The developed Disk Rover is 25 kg in weight including controller and battery, about 685 mm in diameter, 239 mm in height and has a pair of permanent magnet disks. It is demonstrated by the experiments that the Disk Rover can move around on the surface of the wall quite smoothly by radio control and has payload of about its own weight. Several considerations are also done in order to surmount bead weld. (author)

  16. LASER BIOLOGY AND MEDICINE: Effect of repetitive laser pulses on the electrical conductivity of intervertebral disc tissue

    Science.gov (United States)

    Omel'chenko, A. I.; Sobol', E. N.

    2009-03-01

    The thermomechanical effect of 1.56-μm fibre laser pulses on intervertebral disc cartilage has been studied using ac conductivity measurements with coaxial electrodes integrated with an optical fibre for laser radiation delivery to the tissue. The observed time dependences of tissue conductivity can be interpreted in terms of hydraulic effects and thermomechanical changes in tissue structure. The laserinduced changes in the electrical parameters of the tissue are shown to correlate with the structural changes, which were visualised using shadowgraph imaging. Local ac conductivity measurements in the bulk of tissue can be used to develop a diagnostic/monitoring system for laser regeneration of intervertebral discs.

  17. [Morpho-functional characteristic of the lumbar area of the human vertebral column in the individuals with various degrees of lumbar lordosis (on the basis of three-dimensional computer modeling)].

    Science.gov (United States)

    Koveshnikov, V G; Mavrich, V V; Bolgova, E S

    2008-01-01

    This investigation was aimed at the evaluation of the borders of individual variability of the human lumbar spine lordosis. 224 nuclear magnetic tomograms of persons of mature age were analyzed using morphometric, statistical methods, method of three-dimensional (3D) computer modeling and finite-element analysis. During the investigation, a hardware-software complex for morphometric research was created together with the new method of development of 3D computer models of the lumbar spine. The application of 3D modeling allowed to extend the knowledge of human spine biomechanics. Tensions and deformations were calculated in all lumbar vertebrae and intervertebral disks on the basis of spine 3D models developed. Finite-element analysis proved that a normal angle of lumbar lordosis was optimal for the transmission of the adequate compression loads, while the extreme forms of individual variability (high degrees of hyper- and hypolordosis), by changing the geometry of the vertebral column, result in the decrease of the functionality of this system.

  18. Intervertebral anticollision constraints improve out-of-plane translation accuracy of a single-plane fluoroscopy-to-CT registration method for measuring spinal motion

    International Nuclear Information System (INIS)

    Lin, Cheng-Chung; Tsai, Tsung-Yuan; Hsu, Shih-Jung; Lu, Tung-Wu; Shih, Ting-Fang; Wang, Ting-Ming

    2013-01-01

    Purpose: The study aimed to propose a new single-plane fluoroscopy-to-CT registration method integrated with intervertebral anticollision constraints for measuring three-dimensional (3D) intervertebral kinematics of the spine; and to evaluate the performance of the method without anticollision and with three variations of the anticollision constraints via an in vitro experiment. Methods: The proposed fluoroscopy-to-CT registration approach, called the weighted edge-matching with anticollision (WEMAC) method, was based on the integration of geometrical anticollision constraints for adjacent vertebrae and the weighted edge-matching score (WEMS) method that matched the digitally reconstructed radiographs of the CT models of the vertebrae and the measured single-plane fluoroscopy images. Three variations of the anticollision constraints, namely, T-DOF, R-DOF, and A-DOF methods, were proposed. An in vitro experiment using four porcine cervical spines in different postures was performed to evaluate the performance of the WEMS and the WEMAC methods. Results: The WEMS method gave high precision and small bias in all components for both vertebral pose and intervertebral pose measurements, except for relatively large errors for the out-of-plane translation component. The WEMAC method successfully reduced the out-of-plane translation errors for intervertebral kinematic measurements while keeping the measurement accuracies for the other five degrees of freedom (DOF) more or less unaltered. The means (standard deviations) of the out-of-plane translational errors were less than −0.5 (0.6) and −0.3 (0.8) mm for the T-DOF method and the R-DOF method, respectively. Conclusions: The proposed single-plane fluoroscopy-to-CT registration method reduced the out-of-plane translation errors for intervertebral kinematic measurements while keeping the measurement accuracies for the other five DOF more or less unaltered. With the submillimeter and subdegree accuracy, the WEMAC method was

  19. Putting pressure on the spine : an osmoviscoelastic FE model of the intervertebral disc

    NARCIS (Netherlands)

    Schroder, Y.

    2008-01-01

    Back pain is a frequently occurring complaint in adults, having a relatively large impact on the European economy due to the fact that it often partially incapacitates the patient. Intervertebral discs are believed to be a key element of back pain. Apart from providing flexibility to the spine,

  20. Link-N: The missing link towards intervertebral disc repair is species-specific.

    Directory of Open Access Journals (Sweden)

    Frances C Bach

    Full Text Available Degeneration of the intervertebral disc (IVD is a frequent cause for back pain in humans and dogs. Link-N stabilizes proteoglycan aggregates in cartilaginous tissues and exerts growth factor-like effects. The human variant of Link-N facilitates IVD regeneration in several species in vitro by inducing Smad1 signaling, but it is not clear whether this is species specific. Dogs with IVD disease could possibly benefit from Link-N treatment, but Link-N has not been tested on canine IVD cells. If Link-N appears to be effective in canines, this would facilitate translation of Link-N into the clinic using the dog as an in vivo large animal model for human IVD degeneration.This study's objective was to determine the effect of the human and canine variant of Link-N and short (s Link-N on canine chondrocyte-like cells (CLCs and compare this to those on already studied species, i.e. human and bovine CLCs. Extracellular matrix (ECM production was determined by measuring glycosaminoglycan (GAG content and histological evaluation. Additionally, the micro-aggregates' DNA content was measured. Phosphorylated (p Smad1 and -2 levels were determined using ELISA.Human (sLink-N induced GAG deposition in human and bovine CLCs, as expected. In contrast, canine (sLink-N did not affect ECM production in human CLCs, while it mainly induced collagen type I and II deposition in bovine CLCs. In canine CLCs, both canine and human (sLink-N induced negligible GAG deposition. Surprisingly, human and canine (sLink-N did not induce Smad signaling in human and bovine CLCs. Human and canine (sLink-N only mildly increased pSmad1 and Smad2 levels in canine CLCs.Human and canine (sLink-N exerted species-specific effects on CLCs from early degenerated IVDs. Both variants, however, lacked the potency as canine IVD regeneration agent. While these studies demonstrate the challenges of translational studies in large animal models, (sLink-N still holds a regenerative potential for humans.

  1. Formation of lamellar cross bridges in the annulus fibrosus of the intervertebral disc is a consequence of vascular regression.

    Science.gov (United States)

    Smith, Lachlan J; Elliott, Dawn M

    2011-05-01

    Cross bridges are radial structures within the highly organized lamellar structure of the annulus fibrosus of the intervertebral disc that connect two or more non-consecutive lamellae. Their origin and function are unknown. During fetal development, blood vessels penetrate deep within the AF and recede during postnatal growth. We hypothesized that cross bridges are the pathways left by these receding blood vessels. Initially, the presence of cross bridges was confirmed in cadaveric human discs aged 25 and 53 years. Next, L1-L2 intervertebral discs (n=4) from sheep ranging in age from 75 days fetal gestation to adult were processed for paraffin histology. Mid-sagittal sections were immunostained for endothelial cell marker PECAM-1. The anterior and posterior AF were imaged using differential interference contrast microscopy, and the following parameters were quantified: total number of distinct lamellae, total number of cross bridges, percentage of cross bridges staining positive for PECAM-1, cross bridge penetration depth (% total lamellae), and PECAM-1 positive cross bridge penetration depth. Cross bridges were first observed at 100 days fetal gestation. The overall number peaked in neonates then remained relatively unchanged. The percentage of PECAM-1 positive cross bridges declined progressively from almost 100% at 100 days gestation to less than 10% in adults. Cross bridge penetration depth peaked in neonates then remained unchanged at subsequent ages. Depth of PECAM-1 positive cross bridges decreased progressively after birth. Findings were similar for both the anterior and posterior. The AF lamellar architecture is established early in development. It later becomes disrupted as a consequence of vascularization. Blood vessels then recede, perhaps due to increasing mechanical stresses in the surrounding matrix. In this study we present evidence that the pathways left by receding blood vessels remain as lamellar cross bridges. It is unclear whether the presence

  2. Understanding Floppy Disks.

    Science.gov (United States)

    Valentine, Pamela

    1980-01-01

    The author describes the floppy disk with an analogy to the phonograph record, and discusses the advantages, disadvantages, and capabilities of hard-sectored and soft-sectored floppy disks. She concludes that, at present, the floppy disk will continue to be the primary choice of personal computer manufacturers and their customers. (KC)

  3. OT1_ipascucc_1: Understanding the Origin of Transition Disks via Disk Mass Measurements

    Science.gov (United States)

    Pascucci, I.

    2010-07-01

    Transition disks are a distinguished group of few Myr-old systems caught in the phase of dispersing their inner dust disk. Three different processes have been proposed to explain this inside-out clearing: grain growth, photoevaporation driven by the central star, and dynamical clearing by a forming giant planet. Which of these processes lead to a transition disk? Distinguishing between them requires the combined knowledge of stellar accretion rates and disk masses. We propose here to use 43.8 hours of PACS spectroscopy to detect the [OI] 63 micron emission line from a sample of 21 well-known transition disks with measured mass accretion rates. We will use this line, in combination with ancillary CO millimeter lines, to measure their gas disk mass. Because gas dominates the mass of protoplanetary disks our approach and choice of lines will enable us to trace the bulk of the disk mass that resides beyond tens of AU from young stars. Our program will quadruple the number of transition disks currently observed with Herschel in this setting and for which disk masses can be measured. We will then place the transition and the ~100 classical/non-transition disks of similar age (from the Herschel KP "Gas in Protoplanetary Systems") in the mass accretion rate-disk mass diagram with two main goals: 1) reveal which gaps have been created by grain growth, photoevaporation, or giant planet formation and 2) from the statistics, determine the main disk dispersal mechanism leading to a transition disk.

  4. Is tomography of intervertebral disc calcification useful in children?

    International Nuclear Information System (INIS)

    Ginalski, J.M.; Landry, M.; Gudinchet, F.; Schnyder, P.

    1992-01-01

    In the past ten years, we have found cervical intervertebral disc calcification in three children on plain films of the cervical spine made because of cervical pain. In each case, we required further radiological investigations, antero-posterior and lateral linear tomography for two children and an axial computed tomography for one child. In each case, tomography revealed no supplementary useful information. On retrospect, we think that these examinations caused unnecessary irradiation and that they should only be carried out in the rare circumstances when disc calcification is associated with neurological symptoms. (orig.)

  5. Is tomography of intervertebral disc calcification useful in children

    Energy Technology Data Exchange (ETDEWEB)

    Ginalski, J M; Landry, M; Gudinchet, F; Schnyder, P [Lausanne Univ. Hospital (Switzerland). Dept. of Radiology

    1992-04-01

    In the past ten years, we have found cervical intervertebral disc calcification in three children on plain films of the cervical spine made because of cervical pain. In each case, we required further radiological investigations, antero-posterior and lateral linear tomography for two children and an axial computed tomography for one child. In each case, tomography revealed no supplementary useful information. On retrospect, we think that these examinations caused unnecessary irradiation and that they should only be carried out in the rare circumstances when disc calcification is associated with neurological symptoms. (orig.).

  6. Evaluation of T2-weighted versus short-tau inversion recovery sagittal sequences in the identification and localization of canine intervertebral disc extrusion with low-field magnetic resonance imaging.

    Science.gov (United States)

    Housley, Daniel; Caine, Abby; Cherubini, Giunio; Taeymans, Olivier

    2017-07-01

    Sagittal T2-weighted sequences (T2-SAG) are the foundation of spinal protocols when screening for the presence of intervertebral disc extrusion. We often utilize sagittal short-tau inversion recovery sequences (STIR-SAG) as an adjunctive screening series, and experience suggests that this combined approach provides superior detection rates. We hypothesized that STIR-SAG would provide higher sensitivity than T2-SAG in the identification and localization of intervertebral disc extrusion. We further hypothesized that the parallel evaluation of paired T2-SAG and STIR-SAG series would provide a higher sensitivity than could be achieved with either independent sagittal series when viewed in isolation. This retrospective diagnostic accuracy study blindly reviewed T2-SAG and STIR-SAG sequences from dogs (n = 110) with surgically confirmed intervertebral disc extrusion. A consensus between two radiologists found no significant difference in sensitivity between T2-SAG and STIR-SAG during the identification of intervertebral disc extrusion (T2-SAG: 92.7%, STIR-SAG: 94.5%, P = 0.752). Nevertheless, STIR-SAG accurately identified intervertebral disc extrusion in 66.7% of cases where the evaluation of T2-SAG in isolation had provided a false negative diagnosis. Additionally, one radiologist found that the parallel evaluation of paired T2-SAG and STIR-SAG series provided a significantly higher sensitivity than T2-SAG in isolation, during the identification of intervertebral disc extrusion (T2-SAG: 78.2%, paired T2-SAG, and STIR-SAG: 90.9%, P = 0.017). A similar nonsignificant trend was observed when the consensus of both radiologists was taken into consideration (T2-SAG: 92.7%, paired T2-SAG, and STIR-SAG = 97.3%, P = 0.392). We therefore conclude that STIR-SAG is capable of identifying intervertebral disc extrusion that is inconspicuous in T2-SAG, and that STIR-SAG should be considered a useful adjunctive sequence during preliminary sagittal screening for intervertebral disc

  7. Exploring Disks Around Planets

    Science.gov (United States)

    Kohler, Susanna

    2017-07-01

    Giant planets are thought to form in circumstellar disks surrounding young stars, but material may also accrete into a smaller disk around the planet. Weve never detected one of these circumplanetary disks before but thanks to new simulations, we now have a better idea of what to look for.Image from previous work simulating a Jupiter-mass planet forming inside a circumstellar disk. The planet has its own circumplanetary disk of accreted material. [Frdric Masset]Elusive DisksIn the formation of giant planets, we think the final phase consists of accretion onto the planet from a disk that surrounds it. This circumplanetary disk is important to understand, since it both regulates the late gas accretion and forms the birthplace of future satellites of the planet.Weve yet to detect a circumplanetary disk thus far, because the resolution needed to spot one has been out of reach. Now, however, were entering an era where the disk and its kinematics may be observable with high-powered telescopes (like the Atacama Large Millimeter Array).To prepare for such observations, we need models that predict the basic characteristics of these disks like the mass, temperature, and kinematic properties. Now a researcher at the ETH Zrich Institute for Astronomy in Switzerland, Judit Szulgyi, has worked toward this goal.Simulating CoolingSzulgyi performs a series of 3D global radiative hydrodynamic simulations of 1, 3, 5, and 10 Jupiter-mass (MJ) giant planets and their surrounding circumplanetary disks, embedded within the larger circumstellar disk around the central star.Density (left column), temperature (center), and normalized angular momentum (right) for a 1 MJ planet over temperatures cooling from 10,000 K (top) to 1,000 K (bottom). At high temperatures, a spherical circumplanetary envelope surrounds the planet, but as the planet cools, the envelope transitions around 64,000 K to a flattened disk. [Szulgyi 2017]This work explores the effects of different planet temperatures and

  8. Hedgehog signaling is required for formation of the notochord sheath and patterning of nuclei pulposi within the intervertebral discs.

    Science.gov (United States)

    Choi, Kyung-Suk; Harfe, Brian D

    2011-06-07

    The vertebrae notochord is a transient rod-like structure that produces secreted factors that are responsible for patterning surrounding tissues. During later mouse embryogenesis, the notochord gives rise to the middle part of the intervertebral disc, called the nucleus pulposus. Currently, very little is known about the molecular mechanisms responsible for forming the intervertebral discs. Here we demonstrate that hedgehog signaling is required for formation of the intervertebral discs. Removal of hedgehog signaling in the notochord and nearby floorplate resulted in the formation of an aberrant notochord sheath that normally surrounds this structure. In the absence of the notochord sheath, small nuclei pulposi were formed, with most notochord cells dispersed throughout the vertebral bodies during embryogenesis. Our data suggest that the formation of the notochord sheath requires hedgehog signaling and that the sheath is essential for maintaining the rod-like structure of the notochord during early embryonic development. As notochord cells form nuclei pulposi, we propose that the notochord sheath functions as a "wrapper" around the notochord to constrain these cells along the vertebral column.

  9. Developments in intervertebral disc disease research: pathophysiology, mechanobiology, and therapeutics.

    Science.gov (United States)

    Weber, Kathryn T; Jacobsen, Timothy D; Maidhof, Robert; Virojanapa, Justin; Overby, Chris; Bloom, Ona; Quraishi, Shaheda; Levine, Mitchell; Chahine, Nadeen O

    2015-03-01

    Low back pain is a leading cause of disability worldwide and the second most common cause of physician visits. There are many causes of back pain, and among them, disc herniation and intervertebral disc degeneration are the most common diagnoses and targets for intervention. Currently, clinical treatment outcomes are not strongly correlated with diagnoses, emphasizing the importance for characterizing more completely the mechanisms of degeneration and their relationships with symptoms. This review covers recent studies elucidating cellular and molecular changes associated with disc mechanobiology, as it relates to degeneration and regeneration. Specifically, we review findings on the biochemical changes in disc diseases, including cytokines, chemokines, and proteases; advancements in disc disease diagnostics using imaging modalities; updates on studies examining the response of the intervertebral disc to injury; and recent developments in repair strategies, including cell-based repair, biomaterials, and tissue engineering. Findings on the effects of the omega-6 fatty acid, linoleic acid, on nucleus pulposus tissue engineering are presented. Studies described in this review provide greater insights into the pathogenesis of disc degeneration and may define new paradigms for early or differential diagnostics of degeneration using new techniques such as systemic biomarkers. In addition, research on the mechanobiology of disease enriches the development of therapeutics for disc repair, with potential to diminish pain and disability associated with disc degeneration.

  10. Treatment of the degenerated intervertebral disc; closure, repair and regeneration of the annulus fibrosus

    NARCIS (Netherlands)

    Sharifi, Shahriar; Bulstra, S.K.; Grijpma, Dirk W.; Kuijer, R.

    2015-01-01

    Degeneration of the intervertebral disc (IVD) and disc herniation are two causes of low back pain. The aetiology of these disorders is unknown, but tissue weakening, which primarily occurs due to inherited genetic factors, ageing, nutritional compromise and loading history, is the basic factor

  11. Increased MMP-2 activity during intervertebral disc degeneration is correlated to MMP-14 levels

    NARCIS (Netherlands)

    Rutges, J. P. H. J.; Kummer, J. A.; Oner, F. C.; Verbout, A. J.; Roestenburg, H. J. A.; Dhert, W. J. A.; Creemers, L. B.

    Intervertebral disc (IVD) degeneration is associated with the increased expression of several matrix metalloproteinases (MMPs), in particular MMP-2. However, little is known about the actual activity of MMP-2 in healthy and degenerated discs, or what mechanisms are involved in its activation. A

  12. Acid-sensing ion channel 2 (asic 2) and trkb interrelationships within the intervertebral disc.

    Science.gov (United States)

    Cuesta, Antonio; Viña, Eliseo; Cabo, Roberto; Vázquez, Gorka; Cobo, Ramón; García-Suárez, Olivia; García-Cosamalón, José; Vega, José A

    2015-01-01

    The cells of the intervertebral disc (IVD) have an unusual acidic and hyperosmotic microenvironment. They express acid-sensing ion channels (ASICs), gated by extracellular protons and mechanical forces, as well as neurotrophins and their signalling receptors. In the nervous tissues some neurotrophins regulate the expression of ASICs. The expression of ASIC2 and TrkB in human normal and degenerated IVD was assessed using quantitative-PCR, Western blot, and immunohistochemistry. Moreover, we investigated immunohistochemically the expression of ASIC2 in the IVD of TrkB-deficient mice. ASIC2 and TrkB mRNAs were found in normal human IVD and both increased significantly in degenerated IVD. ASIC2 and TrkB proteins were also found co-localized in a variable percentage of cells, being significantly higher in degenerated IVD than in controls. The murine IVD displayed ASIC2 immunoreactivity which was absent in the IVD of TrkB-deficient mice. Present results demonstrate the occurrence of ASIC2 and TrkB in the human IVD, and the increased expression of both in pathological IVD suggest their involvement in IVD degeneration. These data also suggest that TrkB-ligands might be involved in the regulation of ASIC2 expression, and therefore in mechanisms by which the IVD cells accommodate to low pH and hypertonicity.

  13. Equilibrium configuration of a stratus floating above accretion disks: Full-disk calculation

    Science.gov (United States)

    Itanishi, Yusuke; Fukue, Jun

    2017-06-01

    We examine floating strati above a luminous accretion disk, supported by the radiative force from the entire disk, and calculate the equilibrium locus, which depends on the disk luminosity and the optical depth of the stratus. Due to the radiative transfer effect (albedo effect), the floating height of the stratus with a finite optical depth generally becomes high, compared with the particle case. In contrast to the case of the near-disk approximation, moreover, the floating height becomes yet higher in the present full-disk calculation, since the intense radiation from the inner disk is taken into account. As a result, when the disk luminosity normalized by the Eddington luminosity is ˜0.3 and the stratus optical depth is around unity, the stable configuration disappears at around r ˜ 50 rg, rg being the Schwarzschild radius, and the stratus would be blown off as a cloudy wind consisting of many strati with appropriate conditions. This luminosity is sufficiently smaller than the Eddington one, and the present results suggest that the radiation-driven cloudy wind can be easily blown off from the sub-Eddington disk, and this can explain various outflows observed in ultra-fast outflow objects as well as in broad-absorption-line quasars.

  14. Geometry of the vertebral bodies and the intervertebral discs in lumbar segments adjacent to spondylolysis and spondylolisthesis: pilot study.

    Science.gov (United States)

    Been, Ella; Li, Ling; Hunter, David J; Kalichman, Leonid

    2011-07-01

    The objective is to evaluate the geometric parameters of vertebral bodies and intervertebral discs in spinal segments adjacent to spondylolysis and spondylolisthesis. This pilot cross-sectional study was an ancillary project to the Framingham Heart Study. The presence of spondylolysis and spondylolisthesis as well as measurements of spinal geometry were identified on CT imaging of 188 individuals. Spinal geometry measurements included lordosis angle, wedging of each lumbar vertebra and intervertebral disc. Last measurements were used to calculate ΣB, the sum of the lumbar L1-L5 body wedge angles; and ΣD, the sum of the lumbar L1-L5 intervertebral disc angles. Using Wilcoxon-Mann-Whitney test we compared the geometric parameters between individuals with no pathology and ones with spondylolysis (with no listhesis) at L5 vertebra, ones with isthmic spondylolisthesis at L5-S1 level, and ones with degenerative spondylolisthesis at L5-S1 level. Spinal geometry in individuals with spondylolysis or listhesis at L5 shows three major patterns: In spondylolysis without listhesis, spinal morphology is similar to that of healthy individuals; In isthmic spondylolisthesis there is high lordosis angle, high L5 vertebral body wedging and very high L4-5 disc wedging; In degenerative spondylolisthesis, spinal morphology shows more lordotic wedging of the L5 vertebral body, and less lordotic wedging of intervertebral discs. In conclusion, there are unique geometrical features of the vertebrae and discs in spondylolysis or listhesis. These findings need to be reproduced in larger scale study.

  15. Posterior Decompression, Lumber Interbody Fusion and Internal Fixation in the Treatment of Upper Lumbar Intervertebral Disc Herniation

    Directory of Open Access Journals (Sweden)

    DONG Zhan

    2014-12-01

    Full Text Available Objective: To assess the clinical outcomes of posterior decompression, interbody fusion and internal fixationfor the treatment of the upper lumbar intervertebral disc herniation. Methods: Twelve patients with the upper lumbar intervertebral disc herniation were treated by posterior decompression, interbosy fusion and internal fixation. The time of the operation, the amount of bleeding and the clinical efficacy were evaluated. Results: The time of operation was (143±36 min and the amount of bleeding during operation was (331.5±47.9 mL. There was no spinal cord and injuries, nerve injury, epidural damage and leakage of cerebrospinal fluid. All patients were followed up for 10~19 months with the average being 12.6 months. The functional scoring of Japanese Orthopedic Association (JOA before the operation was (11.4±3.3 scores and final score after follow-up was (22.9±3.1 scores and there were statistical difference (P<0.01. Lumber interbody fusion of all patients completed successfully and the good rate after the operation was 91.7%. Conclusion: Posterior decompression, interbody fusion and internal fixation for the treatment of the upper lumbar intervertebral disc herniation was characterized by full exposure, safety and significant efficacy.

  16. Biomechanical effect of altered lumbar lordosis on intervertebral lumbar joints during the golf swing: a simulation study.

    Science.gov (United States)

    Bae, Tae Soo; Cho, Woong; Kim, Kwon Hee; Chae, Soo Won

    2014-11-01

    Although the lumbar spine region is the most common site of injury in golfers, little research has been done on intervertebral loads in relation to the anatomical-morphological differences in the region. This study aimed to examine the biomechanical effects of anatomical-morphological differences in the lumbar lordosis on the lumbar spinal joints during a golf swing. The golf swing motions of ten professional golfers were analyzed. Using a subject-specific 3D musculoskeletal system model, inverse dynamic analyses were performed to compare the intervertebral load, the load on the lumbar spine, and the load in each swing phase. In the intervertebral load, the value was the highest at the L5-S1 and gradually decreased toward the T12. In each lumbar spine model, the load value was the greatest on the kypholordosis (KPL) followed by normal lordosis (NRL), hypolordosis (HPL), and excessive lordosis (EXL) before the impact phase. However, results after the follow-through (FT) phase were shown in reverse order. Finally, the load in each swing phase was greatest during the FT phase in all the lumbar spine models. The findings can be utilized in the training and rehabilitation of golfers to help reduce the risk of injury by considering individual anatomical-morphological characteristics.

  17. Quantitative in vivo MRI evaluation of lumbar facet joints and intervertebral discs using axial T2 mapping.

    Science.gov (United States)

    Stelzeneder, David; Messner, Alina; Vlychou, Marianna; Welsch, Goetz H; Scheurecker, Georg; Goed, Sabine; Pieber, Karin; Pflueger, Verena; Friedrich, Klaus M; Trattnig, Siegfried

    2011-11-01

    To assess the feasibility of T2 mapping of lumbar facet joints and intervertebral discs in a single imaging slab and to compare the findings with morphological grading. Sixty lumbar spine segments from 10 low back pain patients and 5 healthy volunteers were examined by axial T2 mapping and morphological MRI at 3.0 Tesla. Regions of interest were drawn on a single slice for the facet joints and the intervertebral discs (nucleus pulposus, anterior and posterior annulus fibrosus). The Weishaupt grading was used for facet joints and the Pfirrmann score was used for morphological disc grading ("normal" vs. "abnormal" discs). The inter-rater agreement was excellent for the facet joint T2 evaluation (r = 0.85), but poor for the morphological Weishaupt grading (kappa = 0.15). The preliminary results show similar facet joint T2 values in segments with normal and abnormal Pfirrmann scores. There was no difference in mean T2 values between facet joints in different Weishaupt grading groups. Facet joint T2 values showed a weak correlation with T2 values of the posterior annulus (r = 0.32) This study demonstrates the feasibility of a combined T2 mapping approach for the facet joints and intervertebral discs using a single axial slab.

  18. Quantitative in vivo MRI evaluation of lumbar facet joints and intervertebral discs using axial T2 mapping

    International Nuclear Information System (INIS)

    Stelzeneder, David; Messner, Alina; Scheurecker, Georg; Goed, Sabine; Friedrich, Klaus M.; Trattnig, Siegfried; Vlychou, Marianna; Welsch, Goetz H.; Pieber, Karin; Pflueger, Verena

    2011-01-01

    To assess the feasibility of T2 mapping of lumbar facet joints and intervertebral discs in a single imaging slab and to compare the findings with morphological grading. Sixty lumbar spine segments from 10 low back pain patients and 5 healthy volunteers were examined by axial T2 mapping and morphological MRI at 3.0 Tesla. Regions of interest were drawn on a single slice for the facet joints and the intervertebral discs (nucleus pulposus, anterior and posterior annulus fibrosus). The Weishaupt grading was used for facet joints and the Pfirrmann score was used for morphological disc grading (''normal'' vs. ''abnormal'' discs). The inter-rater agreement was excellent for the facet joint T2 evaluation (r = 0.85), but poor for the morphological Weishaupt grading (kappa = 0.15). The preliminary results show similar facet joint T2 values in segments with normal and abnormal Pfirrmann scores. There was no difference in mean T2 values between facet joints in different Weishaupt grading groups. Facet joint T2 values showed a weak correlation with T2 values of the posterior annulus (r = 0.32) This study demonstrates the feasibility of a combined T2 mapping approach for the facet joints and intervertebral discs using a single axial slab. (orig.)

  19. Calcification of intervertebral discs in the dachshund: a radiographic study of 327 young dogs

    International Nuclear Information System (INIS)

    Stigen, Ø.

    1991-01-01

    The vertebral columns of 327 clinically normal, 12 to 18 months old dachshunds, were x-rayed. This sample represented 16.1% of all dachshunds registered with the Norwegian Kennel Club in the period 1986-1988. Calcified intervertebral discs were identified in 79 (24.2%) of the dogs and the number of calcified discs in each individual varied from 1 to 11 with a mean of 2.3. Calcified discs were estimated to occur in 23.5% of Norwegian dachshunds. The occurrence of calcified discs in standard-sized dachshunds was higher in the wirehaired variety (27.1%) than in the smoothcoated (16.4%) or longhaired (9.1%) varieties. However, within the longhaired variety the occurrence was higher in dwarfs and kaninchens (36.0%) than in standard-sized dachshunds (9.1%). Calcification was identified in all cervical, thoracic and lumbar intervertebral discs other than T1-2, and was found to be most frequent in the caudal thoracic vertebral column

  20. Calcification of intervertebral discs in the dachshund: a radiographic study of 327 young dogs

    Energy Technology Data Exchange (ETDEWEB)

    Stigen, Ø. [Norwegian Coll. of Veterinary Medicine, Oslo (Norway)

    1991-07-01

    The vertebral columns of 327 clinically normal, 12 to 18 months old dachshunds, were x-rayed. This sample represented 16.1% of all dachshunds registered with the Norwegian Kennel Club in the period 1986-1988. Calcified intervertebral discs were identified in 79 (24.2%) of the dogs and the number of calcified discs in each individual varied from 1 to 11 with a mean of 2.3. Calcified discs were estimated to occur in 23.5% of Norwegian dachshunds. The occurrence of calcified discs in standard-sized dachshunds was higher in the wirehaired variety (27.1%) than in the smoothcoated (16.4%) or longhaired (9.1%) varieties. However, within the longhaired variety the occurrence was higher in dwarfs and kaninchens (36.0%) than in standard-sized dachshunds (9.1%). Calcification was identified in all cervical, thoracic and lumbar intervertebral discs other than T1-2, and was found to be most frequent in the caudal thoracic vertebral column.

  1. Genome-Wide Association Study in Dachshund: Identification of a Major Locus Affecting Intervertebral Disc Calcification

    DEFF Research Database (Denmark)

    Mogensen, Mette Sloth; Karlskov-Mortensen, Peter; Proschowsky, Helle Friis

    2011-01-01

    Intervertebral disc calcification and herniation commonly affects Dachshund where the predisposition is caused by an early onset degenerative process resulting in disc calcification. A continuous spectrum of disc degeneration is seen within and among clog breeds, suggesting a multifactorial etiol...

  2. Level of Education as a Risk Factor for Extensive Prevalence of Cervical Intervertebral Disc Degenerative Changes and Chronic Neck Pain.

    Science.gov (United States)

    Markotić, Vedran; Zubac, Damir; Miljko, Miro; Šimić, Goran; Zalihić, Amra; Bogdan, Gojko; Radančević, Dorijan; Šimić, Ana Dugandžić; Mašković, Josip

    2017-09-01

    The aim of this study was to document the prevalence of degenerative intervertebral disc changes in the patients who previously reported symptoms of neck pain and to determine the influence of education level on degenerative intervertebral disc changes and subsequent chronic neck pain. One hundred and twelve patients were randomly selected from the University Hospital in Mostar, Bosna and Herzegovina, (aged 48.5±12.7 years) and submitted to magnetic resonance imaging (MRI) of the cervical spine. MRI of 3.0 T (Siemens, Skyrim, Erlangen, Germany) was used to obtain cervical spine images. Patients were separated into two groups based on their education level: low education level (LLE) and high education level (HLE). Pfirrmann classification was used to document intervertebral disc degeneration, while self-reported chronic neck pain was evaluated using the previously validated Oswestry questionnaire. The entire logistic regression model containing all predictors was statistically significant, (χ 2 (3)=12.2, p=0.02), and was able to distinguish between respondents who had chronic neck pain and vice versa. The model explained between 10.0% (Cox-Snell R 2 ) and 13.8% (Nagelkerke R 2 ) of common variance with Pfirrmann classification, and it had the strength to discriminate and correctly classify 69.6% of patients. The probability of a patient being classified in the high or low group of degenerative disc changes according to the Pfirrmann scale was associated with the education level (Wald test: 5.5, p=0.02). Based on the Pfirrmann assessment scale, the HLE group was significantly different from the LLE group in the degree of degenerative changes of the cervical intervertebral discs (U=1,077.5, p=0.001). A moderate level of intervertebral disc degenerative changes (grade II and III) was equally matched among all patients, while the overall results suggest a higher level of education as a risk factor leading to cervical disc degenerative changes, regardless of age

  3. Calcification of intervertebral discs in children

    International Nuclear Information System (INIS)

    Hoermann, D.

    1984-01-01

    Thirteen children with intervertebral disc calcifications of the cervical, thoracal and lumbar spine have been diagnosed since 1970. Most of them were observed over a period of several years. Ten children fell ill with acute pains, but only 2 of them sufferred from a trauma. In 3 cases the features were discovered accidentally combined with malformations of vertebral bodies and congenital diseases. Our results suggest a primary structural inferiority of the calcified discs. The calcifications arise partially from a birth trauma, partially from an unknown etiology. They can last for a long time without symptoms. An acute event effects the pains due to shifting or herniation of calcified disc-fragments. Secondary findings such as decrease of the height of cervical vertebral bodies or destructions of the endplates of thoracal and lumbar vertebral bodies disappear retarded and often incompletely and demand a control for a long time. (orig.)

  4. 2TB hard disk drive

    CERN Multimedia

    This particular object was used up until 2012 in the Data Centre. It slots into one of the Disk Server trays. Hard disks were invented in the 1950s. They started as large disks up to 20 inches in diameter holding just a few megabytes (link is external). They were originally called "fixed disks" or "Winchesters" (a code name used for a popular IBM product). They later became known as "hard disks" to distinguish them from "floppy disks (link is external)." Hard disks have a hard platter that holds the magnetic medium, as opposed to the flexible plastic film found in tapes and floppies.

  5. Mice with a targeted deletion of the tetranectin gene exhibit a spinal deformity

    DEFF Research Database (Denmark)

    Iba, K; Durkin, M E; Johnsen, L

    2001-01-01

    and muscle. To test the functional role of tetranectin directly, we have generated mice with a targeted disruption of the gene. We report that the tetranectin-deficient mice exhibit kyphosis, a type of spinal deformity characterized by an increased curvature of the thoracic spine. The kyphotic angles were...... in the morphology of the vertebrae. Histological analysis of the spines of these mice revealed an apparently asymmetric development of the growth plate and of the intervertebral disks of the vertebrae. In the most advanced cases, the growth plates appeared disorganized and irregular, with the disk material...... in tissue growth and remodeling. The tetranectin-deficient mouse is the first mouse model that resembles common human kyphotic disorders, which affect up to 8% of the population....

  6. DISK DETECTIVE: DISCOVERY OF NEW CIRCUMSTELLAR DISK CANDIDATES THROUGH CITIZEN SCIENCE

    Energy Technology Data Exchange (ETDEWEB)

    Kuchner, Marc J.; McElwain, Michael; Padgett, Deborah L. [NASA Goddard Space Flight Center Exoplanets and Stellar Astrophysics Laboratory, Code 667 Greenbelt, MD 21230 (United States); Silverberg, Steven M.; Wisniewski, John P. [Homer L. Dodge Department of Physics and Astronomy The University of Oklahoma 440 W. Brooks St. Norman, OK 73019 (United States); Bans, Alissa S. [Valparaiso University, Department of Physics and Astronomy, Neils Science Center, 1610 Campus Drive East, Valparaiso, IN 46383 (United States); Bhattacharjee, Shambo [International Space University 1 Rue Jean-Dominique Cassini F-67400 Illkirch-Graffenstaden (France); Kenyon, Scott J. [Smithsonian Astrophysical Observatory 60 Garden Street Cambridge, MA 02138 (United States); Debes, John H. [Space Telescope Science Institute 3700 San Martin Dr. Baltimore, MD 21218 (United States); Currie, Thayne [National Astronomical Observatory of Japan 650 N A’ohokhu Place Hilo, HI 96720 (United States); García, Luciano [Observatorio Astronómico de Córdoba Universidad Nacional de Córdoba Laprida 854, X5000BGR, Córdoba (Argentina); Jung, Dawoon [Korea Aerospace Research Institute Lunar Exploration Program Office 169-84 Gwahak-ro, Yuseong-gu, Daejeon 34133 (Korea, Republic of); Lintott, Chris [Denys Wilkinson Building Keble Road Oxford, OX1 3RH (United Kingdom); Rebull, Luisa M. [Infrared Processing and Analaysis Center Caltech M/S 314-6 1200 E. California Blvd. Pasadena, CA 91125 (United States); Nesvold, Erika, E-mail: Marc.Kuchner@nasa.gov, E-mail: michael.w.mcelwain@nasa.gov, E-mail: deborah.l.padgett@nasa.gov, E-mail: carol.a.grady@nasa.gov, E-mail: silverberg@ou.edu, E-mail: wisniewski@ou.edu [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305 (United States); Collaboration: Disk Detective Collaboration; and others

    2016-10-20

    The Disk Detective citizen science project aims to find new stars with 22 μ m excess emission from circumstellar dust using data from NASA’s Wide-field Infrared Survey Explorer ( WISE ) mission. Initial cuts on the AllWISE catalog provide an input catalog of 277,686 sources. Volunteers then view images of each source online in 10 different bands to identify false positives (galaxies, interstellar matter, image artifacts, etc.). Sources that survive this online vetting are followed up with spectroscopy on the FLWO Tillinghast telescope. This approach should allow us to unleash the full potential of WISE for finding new debris disks and protoplanetary disks. We announce a first list of 37 new disk candidates discovered by the project, and we describe our vetting and follow-up process. One of these systems appears to contain the first debris disk discovered around a star with a white dwarf companion: HD 74389. We also report four newly discovered classical Be stars (HD 6612, HD 7406, HD 164137, and HD 218546) and a new detection of 22 μ m excess around the previously known debris disk host star HD 22128.

  7. DISK DETECTIVE: DISCOVERY OF NEW CIRCUMSTELLAR DISK CANDIDATES THROUGH CITIZEN SCIENCE

    International Nuclear Information System (INIS)

    Kuchner, Marc J.; McElwain, Michael; Padgett, Deborah L.; Silverberg, Steven M.; Wisniewski, John P.; Bans, Alissa S.; Bhattacharjee, Shambo; Kenyon, Scott J.; Debes, John H.; Currie, Thayne; García, Luciano; Jung, Dawoon; Lintott, Chris; Rebull, Luisa M.; Nesvold, Erika

    2016-01-01

    The Disk Detective citizen science project aims to find new stars with 22 μ m excess emission from circumstellar dust using data from NASA’s Wide-field Infrared Survey Explorer ( WISE ) mission. Initial cuts on the AllWISE catalog provide an input catalog of 277,686 sources. Volunteers then view images of each source online in 10 different bands to identify false positives (galaxies, interstellar matter, image artifacts, etc.). Sources that survive this online vetting are followed up with spectroscopy on the FLWO Tillinghast telescope. This approach should allow us to unleash the full potential of WISE for finding new debris disks and protoplanetary disks. We announce a first list of 37 new disk candidates discovered by the project, and we describe our vetting and follow-up process. One of these systems appears to contain the first debris disk discovered around a star with a white dwarf companion: HD 74389. We also report four newly discovered classical Be stars (HD 6612, HD 7406, HD 164137, and HD 218546) and a new detection of 22 μ m excess around the previously known debris disk host star HD 22128.

  8. Disk Detective: Discovery of New Circumstellar Disk Candidates Through Citizen Science

    Science.gov (United States)

    Kuchner, Marc J.; Silverberg, Steven M.; Bans, Alissa S.; Bhattacharjee, Shambo; Kenyon, Scott J.; Debes, John H.; Currie, Thayne; Garcia, Luciano; Jung, Dawoon; Lintott, Chris; hide

    2016-01-01

    The Disk Detective citizen science project aims to find new stars with 22 micron excess emission from circumstellar dust using data from NASAs Wide-field Infrared Survey Explorer (WISE) mission. Initial cuts on the AllWISE catalog provide an input catalog of 277,686 sources. Volunteers then view images of each source online in 10different bands to identify false positives (galaxies, interstellar matter, image artifacts, etc.). Sources that survive this online vetting are followed up with spectroscopy on the FLWO Tillinghast telescope. This approach should allow us to unleash the full potential of WISE for finding new debris disks and proto planetary disks. We announce a first list of 37 new disk candidates discovered by the project, and we describe our vetting and follow-up process. One of these systems appears to contain the first debris disk discovered around a star with a white dwarf companion: HD 74389. We also report four newly discovered classical Be stars (HD 6612, HD 7406, HD 164137,and HD 218546) and a new detection of 22 micron excess around the previously known debris disk host star HD 22128.

  9. Magnetohydrodynamics of accretion disks

    International Nuclear Information System (INIS)

    Torkelsson, U.

    1994-04-01

    The thesis consists of an introduction and summary, and five research papers. The introduction and summary provides the background in accretion disk physics and magnetohydrodynamics. The research papers describe numerical studies of magnetohydrodynamical processes in accretion disks. Paper 1 is a one-dimensional study of the effect of magnetic buoyancy on a flux tube in an accretion disk. The stabilizing influence of an accretion disk corona on the flux tube is demonstrated. Paper 2-4 present numerical simulations of mean-field dynamos in accretion disks. Paper 11 verifies the correctness of the numerical code by comparing linear models to previous work by other groups. The results are also extended to somewhat modified disk models. A transition from an oscillatory mode of negative parity for thick disks to a steady mode of even parity for thin disks is found. Preliminary results for nonlinear dynamos at very high dynamo numbers are also presented. Paper 3 describes the bifurcation behaviour of the nonlinear dynamos. For positive dynamo numbers it is found that the initial steady solution is replaced by an oscillatory solution of odd parity. For negative dynamo numbers the solution becomes chaotic at sufficiently high dynamo numbers. Paper 4 continues the studies of nonlinear dynamos, and it is demonstrated that a chaotic solution appears even for positive dynamo numbers, but that it returns to a steady solution of mixed parity at very high dynamo numbers. Paper 5 describes a first attempt at simulating the small-scale turbulence of an accretion disk in three dimensions. There is only find cases of decaying turbulence, but this is rather due to limitations of the simulations than that turbulence is really absent in accretion disks

  10. Preparation of thin actinide metal disks using a multiple disk casting technique

    International Nuclear Information System (INIS)

    Conner, W.V.

    1975-01-01

    A casting technique has been developed for preparing multiple actinide metal disks which have a minimum thickness of 0.006 inch. This technique was based on an injection casting procedure which utilizes the weight of a tantalum metal rod to force the molten metal into the mold cavity. Using the proper mold design and casting parameters, it has been possible to prepare ten 1/2 inch diameter neptunium or plutonium metal disks in a single casting, This casting technique is capable of producing disks which are very uniform. The average thickness of the disks from a typical casting will vary no more than 0.001 inch and the variation in the thickness of the individual disks will range from 0.0001 to 0.0005 inch. (Auth.)

  11. Preparation of thin actinide metal disks using a multiple disk casting technique

    International Nuclear Information System (INIS)

    Conner, W.V.

    1976-01-01

    A casting technique has been developed for preparing multiple actinide metal disks which have a minimum thickness of 0.006 inch. This technique was based on an injection casting procedure which utilizes the weight of a tantalum metal rod to force the molten metal into the mold cavity. Using the proper mold design and casting parameters, it has been possible to prepare ten 1/2 inch diameter neptunium or plutonium metal disks in a single casting. This casting technique is capable of producing disks which are very uniform. The average thickness of the disks from a typical casting will vary no more than 0.001 inch and the variation in the thickness of the individual disks will range from 0.0001 to 0.0005 inch. (author)

  12. Mechanoreceptors in Diseased Cervical Intervertebral Disc and Vertigo.

    Science.gov (United States)

    Yang, Liang; Yang, Cheng; Pang, Xiaodong; Li, Duanming; Yang, Hong; Zhang, Xinwu; Yang, Yi; Peng, Baogan

    2017-04-15

    We collected the samples of cervical intervertebral discs from patients with vertigo to examine the distribution and types of mechanoreceptors in diseased cervical disc. The aim of this study was to determine whether mechanoreceptors are distributed more abundantly in cervical discs from patients with cervical spondylosis, and whether they are related to vertigo. Previous limited studies have found that normal cervical intervertebral discs are supplied with mechanoreceptors that have been considered responsible for proprioceptive functions. Several clinical studies have indicated that the patients with cervical spondylosis manifested significantly impaired postural control and subjective balance disturbance. We collected 77 samples of cervical discs from 62 cervical spondylosis patients without vertigo, 61 samples from 54 patients with vertigo, and 40 control samples from 8 cadaveric donors to investigate distribution of mechanoreceptors containing neurofilament (NF200) and S-100 protein immunoreactive nerve endings. The immunohistochemical investigation revealed that the most frequently encountered mechanoreceptors were the Ruffini corpuscles in all groups of cervical disc samples. They were obviously increased in the number and deeply ingrown into inner annulus fibrosus and even into nucleus pulposus in the diseased cervical discs from patients with vertigo in comparison with the discs from patients without vertigo and control discs. Only three Golgi endings were seen in the three samples from patients with vertigo. No Pacinian corpuscles were found in any samples of cervical discs. The diseased cervical discs from patients with vertigo had more abundant distribution of Ruffini corpuscles than other discs. A positive association between the increased number and ingrowth of Ruffini corpuscles in the diseased cervical disc and the incidence of vertigo in the patients with cervical spondylosis was found, which may indicate a key role of Ruffini corpuscles in the

  13. Low virulence bacterial infections in cervical intervertebral discs: a prospective case series.

    Science.gov (United States)

    Chen, Yilei; Wang, Xianjun; Zhang, Xuyang; Ren, Hong; Huang, Bao; Chen, Jian; Liu, Junhui; Shan, Zhi; Zhu, Zhihai; Zhao, Fengdong

    2018-04-19

    A prospective cross-sectional case series study. To investigate the prevalence of low virulence disc infection and its associations with characteristics of patients or discs in the cervical spine. Low virulence bacterial infections could be a possible cause of intervertebral disc degeneration and/or back pain. Controversies are continuing over whether these bacteria, predominantly Propionibacterium acnes (P. acnes), represent infection or contamination. However, the current studies mainly focus on the lumbar spine, with very limited data on the cervical spine. Thirty-two patients (20 men and 12 women) who underwent anterior cervical fusion for degenerative cervical spondylosis or traumatic cervical cord injury were enrolled. Radiological assessments included X-ray, CT, and MRI of the cervical spine. Endplate Modic changes, intervertebral range of motion, and disc herniation type were evaluated. Disc and muscle tissues were collected under strict sterile conditions. Samples were enriched in tryptone soy broth and subcultured under anaerobic conditions, followed by identification of the resulting colonies by the PCR method. Sixty-six intervertebral discs were excised from thirty-two patients. Positive disc cultures were noted in eight patients (25%) and in nine discs (13.6%). The muscle biopsy (control) cultures were negative in 28 patients and positive in 4 patients (12.5%); three of whom had a negative disc culture. Seven discs (10.6%) were positive for coagulase-negative Staphylococci (CNS) and two discs were positive for P. acnes (3.0%). A younger patient age and the extrusion or sequestration type of disc herniation, which represented a complete annulus fibrous failure, were associated with positive disc culture. Our data show that CNS is more prevalent than P. acnes in degenerative cervical discs. The infection route in cervical discs may be predominantly through an annulus fissure. Correlation between these infections and clinical symptoms is uncertain

  14. The distribution of lumbar intervertebral angles in upright standing and extension is related to low back pain developed during standing.

    Science.gov (United States)

    Viggiani, Daniel; Gallagher, Kaitlin M; Sehl, Michael; Callaghan, Jack P

    2017-11-01

    Lumbar lordosis measures are poorly related to clinical low back pain, however using a controlled exposure such as prolonged standing to identify pain groups may clarify this relationship. The purpose of this study was to determine the distribution of lumbar intervertebral angles in asymptomatic persons who do (pain developers) and do not (non-pain developers) develop low back pain during standing. Sagittal plane lumbar spine radiographs of eight pain developers and eight non-pain developers were taken in three poses: upright standing, full extension and full flexion. Measures of vertebral end plate orientations from L1 to S1 were taken in each pose to compute: intervertebral angles, contribution of each level to the total curve, total lordosis, ranges of motion, relative pose positioning within the range of motion, vertebral shape, and lumbar spine recurve. Measures were compared between pain groups and lumbar levels. Pain group differences in intervertebral angles and level contributions were greatest in the full extension pose, with pain developers having greater contributions from higher lumbar levels and fewer contributions from lower levels than non-pain developers. Pain group differences in intervertebral angle distributions were less pronounced in upright standing and non-existent in full flexion. No other measures differentiated pain groups. Although participants had similar gross-lumbar spine curvature characteristics, non-pain developers have more curvature at lower levels in upright standing and full extension. These differences in regional vertebral kinematics may partially be responsible for standing-induced low back pain. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. ON THE TRANSITIONAL DISK CLASS: LINKING OBSERVATIONS OF T TAURI STARS AND PHYSICAL DISK MODELS

    International Nuclear Information System (INIS)

    Espaillat, C.; Andrews, S.; Qi, C.; Wilner, D.; Ingleby, L.; Calvet, N.; Hernández, J.; Furlan, E.; D'Alessio, P.; Muzerolle, J.

    2012-01-01

    Two decades ago 'transitional disks' (TDs) described spectral energy distributions (SEDs) of T Tauri stars with small near-IR excesses, but significant mid- and far-IR excesses. Many inferred this indicated dust-free holes in disks possibly cleared by planets. Recently, this term has been applied disparately to objects whose Spitzer SEDs diverge from the expectations for a typical full disk (FD). Here, we use irradiated accretion disk models to fit the SEDs of 15 such disks in NGC 2068 and IC 348. One group has a 'dip' in infrared emission while the others' continuum emission decreases steadily at all wavelengths. We find that the former have an inner disk hole or gap at intermediate radii in the disk and we call these objects 'transitional disks' and 'pre-transitional disks' (PTDs), respectively. For the latter group, we can fit these SEDs with FD models and find that millimeter data are necessary to break the degeneracy between dust settling and disk mass. We suggest that the term 'transitional' only be applied to objects that display evidence for a radical change in the disk's radial structure. Using this definition, we find that TDs and PTDs tend to have lower mass accretion rates than FDs and that TDs have lower accretion rates than PTDs. These reduced accretion rates onto the star could be linked to forming planets. Future observations of TDs and PTDs will allow us to better quantify the signatures of planet formation in young disks.

  16. Comparison between cranial thoracic intervertebral disc herniations in German Shepherd dogs and other large breed dogs.

    Science.gov (United States)

    Gaitero, Luis; Nykamp, Stephanie; Daniel, Rob; Monteith, Gabrielle

    2013-01-01

    Cranial thoracic intervertebral disc herniations have been reported to be rare in dogs due to the presence of the intercapital ligament, however some studies have proposed they may not be uncommon in German Shepherd dogs. The purpose of this retrospective study was to compare cranial thoracic intervertebral disc herniations in German Shepherd dogs and other large breed dogs (control group). Medical records at the Ontario Veterinary College were searched for German Shepherd dogs and other large breed dogs that had magnetic resonance imaging studies including the T1-T9 region. For each dog and each disc space from T1-T9, three variables (compression, disc degeneration, and herniation) were recorded and graded based on review of sagittal T2-weighted images. Twenty-three German Shepherd dogs and 47 other large breed dogs met inclusion criteria. The German Shepherd dog group had higher scores than the control group for compression (P = 0.0099) and herniation (P dog group, intervertebral discs T2-T3 and T4-T5 had an increased risk for compression and T3-T4 had an increased risk for compression and herniation. Findings from this study indicated that German Shepherd dogs may be more likely than other large breed dogs to have spinal cord compression due to cranial thoracic disc herniations. Imaging of the cranial thoracic spine, including T2-T3, is recommended for German Shepherd dogs with T3-L3 neurological signs. © 2012 Veterinary Radiology & Ultrasound.

  17. THE SPITZER INFRARED SPECTROGRAPH SURVEY OF PROTOPLANETARY DISKS IN ORION A. I. DISK PROPERTIES

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K. H. [Korea Astronomy and Space Science Institute (KASI), 776, Daedeokdae-ro, Yuseong-gu, Daejeon 305-348 (Korea, Republic of); Watson, Dan M.; Manoj, P.; Forrest, W. J. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Furlan, Elise [Infrared Processing and Analysis Center, Caltech, 770 S. Wilson Avenue, Pasadena, CA 91125 (United States); Najita, Joan [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Sargent, Benjamin [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Dr., Rochester, NY 14623 (United States); Hernández, Jesús [Centro de Investigaciones de Astronomía, Apdo. Postal 264, Mérida 5101-A (Venezuela, Bolivarian Republic of); Calvet, Nuria [Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States); Adame, Lucía [Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Nuevo León, Av. Universidad S/N, San Nicolás de los Garza, Nuevo León, C.P. 66451, México (Mexico); Espaillat, Catherine [Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Megeath, S. T. [Ritter Astrophysical Research Center, Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft St., Toledo, OH 43606 (United States); Muzerolle, James, E-mail: quarkosmos@kasi.re.kr [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others

    2016-09-01

    We present our investigation of 319 Class II objects in Orion A observed by Spitzer /IRS. We also present the follow-up observations of 120 of these Class II objects in Orion A from the Infrared Telescope Facility/SpeX. We measure continuum spectral indices, equivalent widths, and integrated fluxes that pertain to disk structure and dust composition from IRS spectra of Class II objects in Orion A. We estimate mass accretion rates using hydrogen recombination lines in the SpeX spectra of our targets. Utilizing these properties, we compare the distributions of the disk and dust properties of Orion A disks with those of Taurus disks with respect to position within Orion A (Orion Nebular Cluster [ONC] and L1641) and with the subgroups by the inferred radial structures, such as transitional disks (TDs) versus radially continuous full disks (FDs). Our main findings are as follows. (1) Inner disks evolve faster than the outer disks. (2) The mass accretion rates of TDs and those of radially continuous FDs are statistically significantly displaced from each other. The median mass accretion rate of radially continuous disks in the ONC and L1641 is not very different from that in Taurus. (3) Less grain processing has occurred in the disks in the ONC compared to those in Taurus, based on analysis of the shape index of the 10 μ m silicate feature ( F {sub 11.3}/ F {sub 9.8}). (4) The 20–31 μ m continuum spectral index tracks the projected distance from the most luminous Trapezium star, θ {sup 1} Ori C. A possible explanation is UV ablation of the outer parts of disks.

  18. Brown dwarf disks with ALMA

    Energy Technology Data Exchange (ETDEWEB)

    Ricci, L.; Isella, A. [Department of Astronomy, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Testi, L.; De Gregorio-Monsalvo, I. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Natta, A. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Scholz, A., E-mail: lricci@astro.caltech.edu [School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland)

    2014-08-10

    We present Atacama Large Millimeter/submillimeter Array continuum and spectral line data at 0.89 mm and 3.2 mm for three disks surrounding young brown dwarfs and very low mass stars in the Taurus star forming region. Dust thermal emission is detected and spatially resolved for all the three disks, while CO(J = 3-2) emission is seen in two disks. We analyze the continuum visibilities and constrain the disks' physical structure in dust. The results of our analysis show that the disks are relatively large; the smallest one has an outer radius of about 70 AU. The inferred disk radii, radial profiles of the dust surface density, and disk to central object mass ratios lie within the ranges found for disks around more massive young stars. We derive from our observations the wavelength dependence of the millimeter dust opacity. In all the three disks, data are consistent with the presence of grains with at least millimeter sizes, as also found for disks around young stars, and confirm that the early stages of the solid growth toward planetesimals occur also around very low-mass objects. We discuss the implications of our findings on models of solids evolution in protoplanetary disks, the main mechanisms proposed for the formation of brown dwarfs and very low-mass stars, as well as the potential of finding rocky and giant planets around very low-mass objects.

  19. Nonviral Gene Delivery of Growth and Differentiation Factor 5 to Human Mesenchymal Stem Cells Injected into a 3D Bovine Intervertebral Disc Organ Culture System

    Directory of Open Access Journals (Sweden)

    Christian Bucher

    2013-01-01

    Full Text Available Intervertebral disc (IVD cell therapy with unconditioned 2D expanded mesenchymal stem cells (MSC is a promising concept yet challenging to realize. Differentiation of MSCs by nonviral gene delivery of growth and differentiation factor 5 (GDF5 by electroporation mediated gene transfer could be an excellent source for cell transplantation. Human MSCs were harvested from bone marrow aspirate and GDF5 gene transfer was achieved by in vitro electroporation. Transfected cells were cultured as monolayers and as 3D cultures in 1.2% alginate bead culture. MSC expressed GDF5 efficiently for up to 21 days. The combination of GDF5 gene transfer and 3D culture in alginate showed an upregulation of aggrecan and SOX9, two markers for chondrogenesis, and KRT19 as a marker for discogenesis compared to untransfected cells. The cells encapsulated in alginate produced more proteoglycans expressed in GAG/DNA ratio. Furthermore, GDF5 transfected MCS injected into an IVD papain degeneration organ culture model showed a partial recovery of the GAG/DNA ratio after 7 days. In this study we demonstrate the potential of GDF5 transfected MSC as a promising approach for clinical translation for disc regeneration.

  20. PLANETESIMAL DISK MICROLENSING

    International Nuclear Information System (INIS)

    Heng, Kevin; Keeton, Charles R.

    2009-01-01

    Motivated by debris disk studies, we investigate the gravitational microlensing of background starlight by a planetesimal disk around a foreground star. We use dynamical survival models to construct a plausible example of a planetesimal disk and study its microlensing properties using established ideas of microlensing by small bodies. When a solar-type source star passes behind a planetesimal disk, the microlensing light curve may exhibit short-term, low-amplitude residuals caused by planetesimals several orders of magnitude below Earth mass. The minimum planetesimal mass probed depends on the photometric sensitivity and the size of the source star, and is lower when the planetesimal lens is located closer to us. Planetesimal lenses may be found more nearby than stellar lenses because the steepness of the planetesimal mass distribution changes how the microlensing signal depends on the lens/source distance ratio. Microlensing searches for planetesimals require essentially continuous monitoring programs that are already feasible and can potentially set constraints on models of debris disks, the progeny of the supposed extrasolar analogues of Kuiper Belts.

  1. Proportional lumbar spine inter-vertebral motion patterns: a comparison of patients with chronic, non-specific low back pain and healthy controls.

    Science.gov (United States)

    Mellor, Fiona E; Thomas, Peter W; Thompson, Paul; Breen, Alan C

    2014-10-01

    Identifying biomechanical subgroups in chronic, non-specific low back pain (CNSLBP) populations from inter-vertebral displacements has proven elusive. Quantitative fluoroscopy (QF) has excellent repeatability and provides continuous standardised inter-vertebral kinematic data from fluoroscopic sequences allowing assessment of mid-range motion. The aim of this study was to determine whether proportional continuous IV rotational patterns were different in patients and controls. A secondary aim was to update the repeatability of QF measurement of range of motion (RoM) for inter-vertebral (IV) rotation. Fluoroscopic sequences were recorded of passive, recumbent coronal and sagittal motion, which was controlled for range and velocity. Segments L2-5 in 40 primary care CNSLBP patients and 40 matched controls were compared. Patients also completed the von Korff Chronic Pain Grade and Roland and Morris Disability Questionnaire. Sequences were processed using automated image tracking algorithms to extract continuous inter-vertebral rotation data. These were converted to continuous proportional ranges of rotation (PR). The continuous proportional range variances were calculated for each direction and combined to produce a single variable representing their fluctuation (CPRV). Inter- and intra-rater repeatability were also calculated for the maximum IV-RoM measurements obtained during controlled trunk motion to provide an updated indication of the reliability and agreement of QF for measuring spine kinematics. CPRV was significantly higher in patients (0.011 vs. 0.008, Mann-Whitney two-sided p = 0.008), implying a mechanical subgroup. Receiver operating characteristic curve analysis found its sensitivity and specificity to be 0.78 % (60-90) and 0.55 % (37-73), respectively (area under the curve 0.672). CPRV was not correlated with pain severity or disability. The repeatability of maximum inter-vertebral range was excellent, but range was only significantly greater in patients

  2. Dusty disks around young stars

    NARCIS (Netherlands)

    Verhoeff, A.

    2009-01-01

    Stars are formed through the collapse of giant molecular clouds. During this contraction the matter spins up and naturally forms a circumstellar disk. Once accretion comes to a halt, these disks are relatively stable. Some disks are known to last up to 10 Myrs. Most disks however, dissipate on

  3. Debris Disks: Probing Planet Formation

    OpenAIRE

    Wyatt, Mark C.

    2018-01-01

    Debris disks are the dust disks found around ~20% of nearby main sequence stars in far-IR surveys. They can be considered as descendants of protoplanetary disks or components of planetary systems, providing valuable information on circumstellar disk evolution and the outcome of planet formation. The debris disk population can be explained by the steady collisional erosion of planetesimal belts; population models constrain where (10-100au) and in what quantity (>1Mearth) planetesimals (>10km i...

  4. Fast, Capacious Disk Memory Device

    Science.gov (United States)

    Muller, Ronald M.

    1990-01-01

    Device for recording digital data on, and playing back data from, memory disks has high recording or playback rate and utilizes available recording area more fully. Two disks, each with own reading/writing head, used to record data at same time. Head on disk A operates on one of tracks numbered from outside in; head on disk B operates on track of same number in sequence from inside out. Underlying concept of device applicable to magnetic or optical disks.

  5. Mass distributions in disk galaxies

    NARCIS (Netherlands)

    Martinsson, Thomas; Verheijen, Marc; Bershady, Matthew; Westfall, Kyle; Andersen, David; Swaters, Rob

    We present results on luminous and dark matter mass distributions in disk galaxies from the DiskMass Survey. As expected for normal disk galaxies, stars dominate the baryonic mass budget in the inner region of the disk; however, at about four optical scale lengths (hR ) the atomic gas starts to

  6. WIND-ACCRETION DISKS IN WIDE BINARIES, SECOND-GENERATION PROTOPLANETARY DISKS, AND ACCRETION ONTO WHITE DWARFS

    International Nuclear Information System (INIS)

    Perets, Hagai B.; Kenyon, Scott J.

    2013-01-01

    Mass transfer from an evolved donor star to its binary companion is a standard feature of stellar evolution in binaries. In wide binaries, the companion star captures some of the mass ejected in a wind by the primary star. The captured material forms an accretion disk. Here, we study the evolution of wind-accretion disks, using a numerical approach which allows us to follow the long-term evolution. For a broad range of initial conditions, we derive the radial density and temperature profiles of the disk. In most cases, wind accretion leads to long-lived stable disks over the lifetime of the asymptotic giant branch donor star. The disks have masses of a few times 10 –5 -10 –3 M ☉ , with surface density and temperature profiles that follow broken power laws. The total mass in the disk scales approximately linearly with the viscosity parameter used. Roughly, 50%-80% of the mass falling into the disk accretes onto the central star; the rest flows out through the outer edge of the disk into the stellar wind of the primary. For systems with large accretion rates, the secondary accretes as much as 0.1 M ☉ . When the secondary is a white dwarf, accretion naturally leads to nova and supernova eruptions. For all types of secondary star, the surface density and temperature profiles of massive disks resemble structures observed in protoplanetary disks, suggesting that coordinated observational programs might improve our understanding of uncertain disk physics.

  7. A High-mass Protobinary System with Spatially Resolved Circumstellar Accretion Disks and Circumbinary Disk

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, S.; Kluska, J.; Kreplin, A.; Bate, M.; Harries, T. J.; Hone, E.; Anugu, A. [School of Physics, Astrophysics Group, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Hofmann, K.-H.; Weigelt, G. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Monnier, J. D. [Department of Astronomy, University of Michigan, 311 West Hall, 1085 South University Avenue, Ann Arbor, MI 48109 (United States); De Wit, W. J. [ESO, Alonso de Cordova 3107, Vitacura, Santiago 19 (Chile); Wittkowski, M., E-mail: skraus@astro.ex.ac.uk [ESO, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München (Germany)

    2017-01-20

    High-mass multiples might form via fragmentation of self-gravitational disks or alternative scenarios such as disk-assisted capture. However, only a few observational constraints exist on the architecture and disk structure of high-mass protobinaries and their accretion properties. Here, we report the discovery of a close (57.9 ± 0.2 mas = 170 au) high-mass protobinary, IRAS17216-3801, where our VLTI/GRAVITY+AMBER near-infrared interferometry allows us to image the circumstellar disks around the individual components with ∼3 mas resolution. We estimate the component masses to ∼20 and ∼18 M {sub ⊙} and find that the radial intensity profiles can be reproduced with an irradiated disk model, where the inner regions are excavated of dust, likely tracing the dust sublimation region in these disks. The circumstellar disks are strongly misaligned with respect to the binary separation vector, which indicates that the tidal forces did not have time to realign the disks, pointing toward a young dynamical age of the system. We constrain the distribution of the Br γ and CO-emitting gas using VLTI/GRAVITY spectro-interferometry and VLT/CRIRES spectro-astrometry and find that the secondary is accreting at a higher rate than the primary. VLT/NACO imaging shows L ′-band emission on (3–4)× larger scales than the binary separation, matching the expected dynamical truncation radius for the circumbinary disk. The IRAS17216-3801 system is ∼3× more massive and ∼5× more compact than other high-mass multiplies imaged at infrared wavelength and the first high-mass protobinary system where circumstellar and circumbinary dust disks could be spatially resolved. This opens exciting new opportunities for studying star–disk interactions and the role of multiplicity in high-mass star formation.

  8. Source to Accretion Disk Tilt

    OpenAIRE

    Montgomery, M. M.; Martin, E. L.

    2010-01-01

    Many different system types retrogradely precess, and retrograde precession could be from a tidal torque by the secondary on a misaligned accretion disk. However, a source to cause and maintain disk tilt is unknown. In this work, we show that accretion disks can tilt due to a force called lift. Lift results from differing gas stream supersonic speeds over and under an accretion disk. Because lift acts at the disk's center of pressure, a torque is applied around a rotation axis passing through...

  9. Evolution of magnetic disk subsystems

    Science.gov (United States)

    Kaneko, Satoru

    1994-06-01

    The higher recording density of magnetic disk realized today has brought larger storage capacity per unit and smaller form factors. If the required access performance per MB is constant, the performance of large subsystems has to be several times better. This article describes mainly the technology for improving the performance of the magnetic disk subsystems and the prospects of their future evolution. Also considered are 'crosscall pathing' which makes the data transfer channel more effective, 'disk cache' which improves performance coupling with solid state memory technology, and 'RAID' which improves the availability and integrity of disk subsystems by organizing multiple disk drives in a subsystem. As a result, it is concluded that since the performance of the subsystem is dominated by that of the disk cache, maximation of the performance of the disk cache subsystems is very important.

  10. STELLAR MASS DEPENDENT DISK DISPERSAL

    International Nuclear Information System (INIS)

    Kennedy, Grant M.; Kenyon, Scott J.

    2009-01-01

    We use published optical spectral and infrared (IR) excess data from nine young clusters and associations to study the stellar mass dependent dispersal of circumstellar disks. All clusters older than ∼3 Myr show a decrease in disk fraction with increasing stellar mass for solar to higher mass stars. This result is significant at about the 1σ level in each cluster. For the complete set of clusters we reject the null hypothesis-that solar and intermediate-mass stars lose their disks at the same rate-with 95%-99.9% confidence. To interpret this behavior, we investigate the impact of grain growth, binary companions, and photoevaporation on the evolution of disk signatures. Changes in grain growth timescales at fixed disk temperature may explain why early-type stars with IR excesses appear to evolve faster than their later-type counterparts. Little evidence that binary companions affect disk evolution suggests that photoevaporation is the more likely mechanism for disk dispersal. A simple photoevaporation model provides a good fit to the observed disk fractions for solar and intermediate-mass stars. Although the current mass-dependent disk dispersal signal is not strong, larger and more complete samples of clusters with ages of 3-5 Myr can improve the significance and provide better tests of theoretical models. In addition, the orbits of extra-solar planets can constrain models of disk dispersal and migration. We suggest that the signature of stellar mass dependent disk dispersal due to photoevaporation may be present in the orbits of observed extra-solar planets. Planets orbiting hosts more massive than ∼1.6 M sun may have larger orbits because the disks in which they formed were dispersed before they could migrate.

  11. Manipulation of magnetic vortex parameters in disk-on-disk nanostructures with various geometry

    Directory of Open Access Journals (Sweden)

    Maxim E. Stebliy

    2015-03-01

    Full Text Available Magnetic nanostructures in the form of a sandwich consisting of two permalloy (Py disks with diameters of 600 and 200 nm separated by a nonmagnetic interlayer are studied. Magnetization reversal of the disk-on-disk nanostructures depends on the distance between centers of the small and big disks and on orientation of an external magnetic field applied during measurements. It is found that manipulation of the magnetic vortex chirality and the trajectory of the vortex core in the big disk is only possible in asymmetric nanostructures. Experimentally studied peculiarities of a motion path of the vortex core and vortex parameters by the magneto-optical Kerr effect (MOKE magnetometer are supported by the magnetic force microscopy imaging and micromagnetic simulations.

  12. Measurement of Intervertebral Motion Using Quantitative Fluoroscopy: Report of an International Forum and Proposal for Use in the Assessment of Degenerative Disc Disease in the Lumbar Spine

    Directory of Open Access Journals (Sweden)

    Alan C. Breen

    2012-01-01

    Full Text Available Quantitative fluoroscopy (QF is an emerging technology for measuring intervertebral motion patterns to investigate problem back pain and degenerative disc disease. This International Forum was a networking event of three research groups (UK, US, Hong Kong, over three days in San Francisco in August 2009. Its aim was to reach a consensus on how best to record, analyse, and communicate QF information for research and clinical purposes. The Forum recommended that images should be acquired during regular trunk motion that is controlled for velocity and range, in order to minimise externally imposed variability as well as to correlate intervertebral motion with trunk motion. This should be done in both the recumbent passive and weight bearing active patient configurations. The main recommended outputs from QF were the true ranges of intervertebral rotation and translation, neutral zone laxity and the consistency of shape of the motion patterns. The main clinical research priority should initially be to investigate the possibility of mechanical subgroups of patients with chronic, nonspecific low back pain by comparing their intervertebral motion patterns with those of matched healthy controls.

  13. Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xue-Ning, E-mail: xbai@cfa.harvard.edu [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS-51, Cambridge, MA 02138 (United States)

    2017-08-10

    The gas dynamics of weakly ionized protoplanetary disks (PPDs) are largely governed by the coupling between gas and magnetic fields, described by three non-ideal magnetohydrodynamical (MHD) effects (Ohmic, Hall, ambipolar). Previous local simulations incorporating these processes have revealed that the inner regions of PPDs are largely laminar and accompanied by wind-driven accretion. We conduct 2D axisymmetric, fully global MHD simulations of these regions (∼1–20 au), taking into account all non-ideal MHD effects, with tabulated diffusion coefficients and approximate treatment of external ionization and heating. With the net vertical field aligned with disk rotation, the Hall-shear instability strongly amplifies horizontal magnetic field, making the overall dynamics dependent on initial field configuration. Following disk formation, the disk likely relaxes into an inner zone characterized by asymmetric field configuration across the midplane, which smoothly transitions to a more symmetric outer zone. Angular momentum transport is driven by both MHD winds and laminar Maxwell stress, with both accretion and decretion flows present at different heights, and modestly asymmetric winds from the two disk sides. With anti-aligned field polarity, weakly magnetized disks settle into an asymmetric field configuration with supersonic accretion flow concentrated at one side of the disk surface, and highly asymmetric winds between the two disk sides. In all cases, the wind is magneto-thermal in nature, characterized by a mass loss rate exceeding the accretion rate. More strongly magnetized disks give more symmetric field configuration and flow structures. Deeper far-UV penetration leads to stronger and less stable outflows. Implications for observations and planet formation are also discussed.

  14. Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics

    Science.gov (United States)

    Bai, Xue-Ning

    2017-08-01

    The gas dynamics of weakly ionized protoplanetary disks (PPDs) are largely governed by the coupling between gas and magnetic fields, described by three non-ideal magnetohydrodynamical (MHD) effects (Ohmic, Hall, ambipolar). Previous local simulations incorporating these processes have revealed that the inner regions of PPDs are largely laminar and accompanied by wind-driven accretion. We conduct 2D axisymmetric, fully global MHD simulations of these regions (˜1-20 au), taking into account all non-ideal MHD effects, with tabulated diffusion coefficients and approximate treatment of external ionization and heating. With the net vertical field aligned with disk rotation, the Hall-shear instability strongly amplifies horizontal magnetic field, making the overall dynamics dependent on initial field configuration. Following disk formation, the disk likely relaxes into an inner zone characterized by asymmetric field configuration across the midplane, which smoothly transitions to a more symmetric outer zone. Angular momentum transport is driven by both MHD winds and laminar Maxwell stress, with both accretion and decretion flows present at different heights, and modestly asymmetric winds from the two disk sides. With anti-aligned field polarity, weakly magnetized disks settle into an asymmetric field configuration with supersonic accretion flow concentrated at one side of the disk surface, and highly asymmetric winds between the two disk sides. In all cases, the wind is magneto-thermal in nature, characterized by a mass loss rate exceeding the accretion rate. More strongly magnetized disks give more symmetric field configuration and flow structures. Deeper far-UV penetration leads to stronger and less stable outflows. Implications for observations and planet formation are also discussed.

  15. Prótese para substituição total de disco intervertebral: desenvolvimento de modelo computacional e análise por elementos finitos Prótese de reemplazo total del disco intervertebral: modelo de desarrollo computacional y análisis de elementos finitos Prosthesis for total intervertebral disc replacement: computacional model development and finite element analysis

    Directory of Open Access Journals (Sweden)

    Tiago Nunes Campello

    2009-03-01

    Full Text Available INTRODUÇÃO: a idéia de um disco intervertebral artificial não é nova. O campo de estudos sobre próteses para artroplastia de coluna desenvolve-se ao passo que novas tecnologias na área de materiais e engenharia médica são desenvolvidas ou introduzidas para o surgimento de novos projetos. OBJETIVO: estabelecer metodologia de desenvolvimento de produto em um projeto de prótese para substituição total de disco intervertebral pela utilização de ferramentas computacionais de engenharia. MÉTODOS: a metodologia de desenvolvimento de prótese para substituição total de disco iniciou-se com a definição do seu modelo virtual, seguida pela a análise mecânica virtual por elementos finitos. RESULTADOS: a prótese de disco foi concebida com três componentes, sendo eles o flange superior, o flange inferior e o núcleo. Aplicando o critério de von Mises para solução da análise virtual, verificou-se que o núcleo da prótese é o componente mais solicitado durante compressão axial e compressão/cisalhamento. CONCLUSÃO: este estudo demonstra a viabilidade do desenvolvimento de um projeto para fabricação de prótese para substituição total de disco intervertebral, por meio de metodologia computacional já consagrada em projetos mecânicos de engenharia, principalmente, nos ramos automotivo e aeronáutico.INTRODUCCIÓN: la idea de un disco intervertebral artificial no es nueva. Los estudios de la columna vertebral artroplastia prótesis están en desarrollo, mientras las nuevas tecnologías en el ámbito de la ingeniería y los materiales médicos son desarr llados o introducidos a la aparición de nuevos proyectos. OBJETIVO: establecer una metodología para el desarrollo de producto en un proyecto de prótesis para reemplazo total del disco intervertebral, a través del uso de herramientas de ingeniería computacional. MÉTODOS: la metodología de desarrollo de prótesis para reemplazo total del disco se inició con la definici

  16. WIND-ACCRETION DISKS IN WIDE BINARIES, SECOND-GENERATION PROTOPLANETARY DISKS, AND ACCRETION ONTO WHITE DWARFS

    Energy Technology Data Exchange (ETDEWEB)

    Perets, Hagai B. [Technion-Israel Institute of Technology, Haifa (Israel); Kenyon, Scott J., E-mail: hperets@physics.technion.ac.il [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2013-02-20

    Mass transfer from an evolved donor star to its binary companion is a standard feature of stellar evolution in binaries. In wide binaries, the companion star captures some of the mass ejected in a wind by the primary star. The captured material forms an accretion disk. Here, we study the evolution of wind-accretion disks, using a numerical approach which allows us to follow the long-term evolution. For a broad range of initial conditions, we derive the radial density and temperature profiles of the disk. In most cases, wind accretion leads to long-lived stable disks over the lifetime of the asymptotic giant branch donor star. The disks have masses of a few times 10{sup -5}-10{sup -3} M {sub Sun }, with surface density and temperature profiles that follow broken power laws. The total mass in the disk scales approximately linearly with the viscosity parameter used. Roughly, 50%-80% of the mass falling into the disk accretes onto the central star; the rest flows out through the outer edge of the disk into the stellar wind of the primary. For systems with large accretion rates, the secondary accretes as much as 0.1 M {sub Sun }. When the secondary is a white dwarf, accretion naturally leads to nova and supernova eruptions. For all types of secondary star, the surface density and temperature profiles of massive disks resemble structures observed in protoplanetary disks, suggesting that coordinated observational programs might improve our understanding of uncertain disk physics.

  17. Expression of receptors for putative anabolic growth factors in human intervertebral disc: implications for repair and regeneration of the disc.

    Science.gov (United States)

    Le Maitre, Christine L; Richardson, Stephen M A; Baird, Pauline; Freemont, Anthony J; Hoyland, Judith A

    2005-12-01

    Low back pain (LBP) is a common, debilitating and economically important disorder. Current evidence implicates loss of intervertebral disc (IVD) matrix consequent upon 'degeneration' as a major cause of LBP. Degeneration of the IVD involves increases in degradative enzymes and decreases in the extracellular matrix (ECM) component in a process that is controlled by a range of cytokines and growth factors. Studies have suggested using anabolic growth factors to regenerate the normal matrix of the IVD, hence restoring disc height and reversing degenerative disc disease. However, for such therapies to be successful it is vital that the target cells (i.e. the disc cells) express the appropriate receptors. This immunohistochemical study has for the first time investigated the expression and localization of four potentially beneficial growth factor receptors (i.e. TGFbetaRII, BMPRII, FGFR3 and IGFRI) in non-degenerate and degenerate human IVDs. Receptor expression was quantified across regions of the normal and degenerate disc and showed that cells of the nucleus pulposus (NP) and inner annulus fibrosus (IAF) expressed significantly higher levels of the four growth factor receptors investigated. There were no significant differences between the four growth factor expression in non-degenerate and degenerate biopsies. However, expression of TGFbetaRII, FGFR3 and IGFRI, but not BMP RII, were observed in the ingrowing blood vessels that characterize part of the disease aetiology. In conclusion, this study has demonstrated the expression of the four growth factor receptors at similar levels in the chondrocyte-like cells of the NP and IAF in both non-degenerate and degenerate discs, implicating a role in normal disc homeostasis and suggesting that the application of these growth factors to the degenerate human IVD would stimulate matrix production. However, the expression of some of the growth factor receptors on ingrowing blood vessels might be problematic in a therapeutic

  18. Vibration of imperfect rotating disk

    Directory of Open Access Journals (Sweden)

    Půst L.

    2011-12-01

    Full Text Available This study is concerned with the theoretical and numerical calculations of the flexural vibrations of a bladed disk. The main focus of this study is to elaborate the basic background for diagnostic and identification methods for ascertaining the main properties of the real structure or an experimental model of turbine disks. The reduction of undesirable vibrations of blades is proposed by using damping heads, which on the experimental model of turbine disk are applied only on a limited number of blades. This partial setting of damping heads introduces imperfection in mass, stiffness and damping distribution on the periphery and leads to more complicated dynamic properties than those of a perfect disk. Calculation of FEM model and analytic—numerical solution of disk behaviour in the limited (two modes frequency range shows the splitting of resonance with an increasing speed of disk rotation. The spectrum of resonance is twice denser than that of a perfect disk.

  19. Computed tomography of the cervical spine with iv injection of contrast medium

    International Nuclear Information System (INIS)

    Magnaldi, S.; Pozzi-Mucelli, R.S.; Cova, M.A.; De Morpurgo, P.

    1989-01-01

    Computed Tomography (CT) without contrast medium is largely applied to the study of intervertebral disk pathology in the lumbar spine, but has not been widely accepted in cervical spine, due to technical and anatomical limitations. For these reasons many neuroradiologists still prefer myelography or myelo-CT. CT may yield better results if combined with iv contrast medium injection, which allows a better visualization of disk herniation. This technique is aimed at enhancing the density of the venous plexus which is located close to the intervertebral disk the vertebral bodies and the neural foramina. A better contrast enhancement is thus obtained between the disk and the spinal cord. The authors' experience is based on 61 patients who underwent contrast enhanced CT; in 22 cases myelography and myelo-CT were also performed. The authors describe their technique and the most frequent CT findings of disk hernation: the typical finding includes a focal hypodensity surrounded by a linear blush, due to a posteriorly dislocated epidural vein. The posterior linear blush alone may be present in few cases. Contrast enhanced CT is very useful in the study of disk pathology of the cervical spine, even when compared with myelography and myelo-CT, due the increase in the density of epidural plexus it allows. However, the technique must be very accurate if the same results as those of myelo-CT are to be obtained

  20. RINGED ACCRETION DISKS: EQUILIBRIUM CONFIGURATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, D.; Stuchlík, Z., E-mail: d.pugliese.physics@gmail.com, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)

    2015-12-15

    We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.

  1. CN rings in full protoplanetary disks around young stars as probes of disk structure

    Science.gov (United States)

    Cazzoletti, P.; van Dishoeck, E. F.; Visser, R.; Facchini, S.; Bruderer, S.

    2018-01-01

    Aims: Bright ring-like structure emission of the CN molecule has been observed in protoplanetary disks. We investigate whether such structures are due to the morphology of the disk itself or if they are instead an intrinsic feature of CN emission. With the intention of using CN as a diagnostic, we also address to which physical and chemical parameters CN is most sensitive. Methods: A set of disk models were run for different stellar spectra, masses, and physical structures via the 2D thermochemical code DALI. An updated chemical network that accounts for the most relevant CN reactions was adopted. Results: Ring-shaped emission is found to be a common feature of all adopted models; the highest abundance is found in the upper outer regions of the disk, and the column density peaks at 30-100 AU for T Tauri stars with standard accretion rates. Higher mass disks generally show brighter CN. Higher UV fields, such as those appropriate for T Tauri stars with high accretion rates or for Herbig Ae stars or for higher disk flaring, generally result in brighter and larger rings. These trends are due to the main formation paths of CN, which all start with vibrationally excited H_2^* molecules, that are produced through far ultraviolet (FUV) pumping of H2. The model results compare well with observed disk-integrated CN fluxes and the observed location of the CN ring for the TW Hya disk. Conclusions: CN rings are produced naturally in protoplanetary disks and do not require a specific underlying disk structure such as a dust cavity or gap. The strong link between FUV flux and CN emission can provide critical information regarding the vertical structure of the disk and the distribution of dust grains which affects the UV penetration, and could help to break some degeneracies in the SED fitting. In contrast with C2H or c-C3H2, the CN flux is not very sensitive to carbon and oxygen depletion.

  2. HERSCHEL OBSERVATIONS OF THE T CHA TRANSITION DISK: CONSTRAINING THE OUTER DISK PROPERTIES

    International Nuclear Information System (INIS)

    Cieza, Lucas A.; Olofsson, Johan; Henning, Thomas; Harvey, Paul M.; Evans II, Neal J.; Pinte, Christophe; Augereau, Jean-Charles; Ménard, Francois; Merín, Bruno; Najita, Joan

    2011-01-01

    T Cha is a nearby (d ∼ 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huélamo et al. recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel photometry (70, 160, 250, 350, and 500 μm) of T Cha from the 'Dust, Ice, and Gas in Time' Key Program, which bridges the wavelength range between existing Spitzer and millimeter data and provide important constraints on the outer disk properties of this extraordinary system. We model the entire optical to millimeter wavelength spectral energy distribution (SED) of T Cha (19 data points between 0.36 and 3300 μm without any major gaps in wavelength coverage). T Cha shows a steep spectral slope in the far-IR, which we find clearly favors models with outer disks containing little or no dust beyond ∼40 AU. The full SED can be modeled equally well with either an outer disk that is very compact (only a few AU wide) or a much larger one that has a very steep surface density profile. That is, T Cha's outer disk seems to be either very small or very tenuous. Both scenarios suggest a highly unusual outer disk and have important but different implications for the nature of T Cha. Spatially resolved images are needed to distinguish between the two scenarios.

  3. HERSCHEL OBSERVATIONS OF THE T CHA TRANSITION DISK: CONSTRAINING THE OUTER DISK PROPERTIES

    Energy Technology Data Exchange (ETDEWEB)

    Cieza, Lucas A. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Olofsson, Johan; Henning, Thomas [Max Planck Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Harvey, Paul M.; Evans II, Neal J. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Pinte, Christophe; Augereau, Jean-Charles; Menard, Francois [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d' Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041 (France); Merin, Bruno [Herschel Science Centre, European Space Agency (ESAC), P.O. Box 78, 28691 Villanueva de la Canada, Madrid (Spain); Najita, Joan, E-mail: lcieza@ifa.hawaii.edu [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 86719 (United States)

    2011-11-10

    T Cha is a nearby (d {approx} 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huelamo et al. recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel photometry (70, 160, 250, 350, and 500 {mu}m) of T Cha from the 'Dust, Ice, and Gas in Time' Key Program, which bridges the wavelength range between existing Spitzer and millimeter data and provide important constraints on the outer disk properties of this extraordinary system. We model the entire optical to millimeter wavelength spectral energy distribution (SED) of T Cha (19 data points between 0.36 and 3300 {mu}m without any major gaps in wavelength coverage). T Cha shows a steep spectral slope in the far-IR, which we find clearly favors models with outer disks containing little or no dust beyond {approx}40 AU. The full SED can be modeled equally well with either an outer disk that is very compact (only a few AU wide) or a much larger one that has a very steep surface density profile. That is, T Cha's outer disk seems to be either very small or very tenuous. Both scenarios suggest a highly unusual outer disk and have important but different implications for the nature of T Cha. Spatially resolved images are needed to distinguish between the two scenarios.

  4. In-vivo Intervertebral Disc Characterization using Magnetic Resonance Spectroscopy and T1ρ Imaging: Association with Discography and Oswestry Disability Index and SF-36

    Science.gov (United States)

    Zuo, Jin; Joseph, Gabby B.; Li, Xiaojuan; Link, Thomas M.; Hu, Serena S.; Berven, Sigurd H.; Kurhanewitz, John; Majumdar, Sharmila

    2011-01-01

    Study Design An in vivo study of intervertebral disc degeneration using quantitative MRI and MRS. Objective To quantify water and proteoglycan (PG) content in the intervertebral disc using in vivo magnetic resonance spectroscopy (MRS), and to evaluate the relationship between MRS- quantified water/PG content, T1ρ, Pfirrmann score, clinical self-assessment, and discography. Summary of Background Data Previous in vitro studies have investigated the relationship between MRS-quantified water/PG content, and degenerative grade using cadaveric intervertebral discs. T1ρ has been shown to relate to Pfirmann grade and clinical self-assessment. However, the associations between MRS-quantified water/PG content, MR imaging-based T1ρ, self-assessment of health status and clinical response to discography have not been studied in vivo. Methods MRS and MR imaging were performed in 26 patients (70 discs) with symptomatic intervertebral degenerative disc (IVDD) and 23 controls (41 discs). Patients underwent evaluation of intervertebral discs with provocative discography. All subjects completed the SF-36 Health Survey and Oswestry Disability Index questionnaires. Results The water/PG peak area ratio was significantly elevated in a) patients (compared to controls) and in b) discs with positive discography (compared to negative discography). MR T1ρ exhibited similar trends. A significant association was found between T1ρ and normalized PG content (R2 = 0.61, p 0.05). The water/PG peak area ratio, normalized water, normalized PG, and Pfirrmann grade were significantly associated with patient self-assessment of disability and physical composite score, while disc height was not. Conclusion This study demonstrated a relationship between in vivo MRS spectroscopy (water content, PG content), imaging parameters (T1ρ, Pfirrmann Grade), discography results, and clinical self-assessment, suggesting that MRS-quantified water, PG and MR T1ρ relaxation time may potentially serve as

  5. Audit: Automated Disk Investigation Toolkit

    Directory of Open Access Journals (Sweden)

    Umit Karabiyik

    2014-09-01

    Full Text Available Software tools designed for disk analysis play a critical role today in forensics investigations. However, these digital forensics tools are often difficult to use, usually task specific, and generally require professionally trained users with IT backgrounds. The relevant tools are also often open source requiring additional technical knowledge and proper configuration. This makes it difficult for investigators without some computer science background to easily conduct the needed disk analysis. In this paper, we present AUDIT, a novel automated disk investigation toolkit that supports investigations conducted by non-expert (in IT and disk technology and expert investigators. Our proof of concept design and implementation of AUDIT intelligently integrates open source tools and guides non-IT professionals while requiring minimal technical knowledge about the disk structures and file systems of the target disk image.

  6. Restriction of Cervical Intervertebral Movement with Different Types of External Immobilizers : A Cadaveric 3D Analysis Study

    NARCIS (Netherlands)

    Holla, Micha; Hannink, Gerjon; Eggen, Thomas G.E.; Daanen, Robin A.; Hosman, Allard J.F.; Verdonschot, Nico

    2017-01-01

    Study Design. Cadaveric radiostereometric analysis study. Objective. To quantify the ability of five commonly used immobilizers to restrict cervical spine movement, including intervertebral movement, in three directions. Summary of Background Data. Evidence about the ability of many clinically used

  7. Restriction of Cervical Intervertebral Movement With Different Types of External Immobilizers: A Cadaveric 3D Analysis Study

    NARCIS (Netherlands)

    Holla, M.; Hannink, G.J.; Eggen, T.G.E.; Daanen, R.A.; Hosman, A.J.F.; Verdonschot, N.J.

    2017-01-01

    STUDY DESIGN: Cadaveric radiostereometric analysis study. OBJECTIVE: To quantify the ability of five commonly used immobilizers to restrict cervical spine movement, including intervertebral movement, in three directions. SUMMARY OF BACKGROUND DATA: Evidence about the ability of many clinically used

  8. YottaYotta announces new world record set for TCP disk-to-disk bulk transfer

    CERN Document Server

    2002-01-01

    The Yottabyte NetStorage(TM) Company, today announced a new world record for TCP disk-to-disk data transfer using the company's NetStorager(R) System. The record-breaking demonstration transferred 5 terabytes of data between Chicago, Il. to Vancouver, BC and Ottawa, ON, at a sustained average throughput of 11.1 gigabits per second. Peak throughput exceeded 11.6 gigabits per second, more than 15-times faster than previous records for TCP transfer from disk-to-disk (1 page).

  9. Disk-to-Disk network transfers at 100 Gb/s

    Science.gov (United States)

    Barczyk, Artur; Gable, Ian; Hay, Marilyn; Leavett-Brown, Colin; Legrand, Iosif; Lewall, Kim; McKee, Shawn; McWilliam, Donald; Mughal, Azher; Newman, Harvey; Rozsa, Sandor; Savard, Yvan; Sobie, Randall J.; Tam, Thomas; Voicu, Ramiro

    2012-12-01

    A 100 Gbps network was established between the California Institute of Technology conference booth at the Super Computing 2011 conference in Seattle, Washington and the computing center at the University of Victoria in Canada. A circuit was established over the BCNET, CANARIE and Super Computing (SCInet) networks using dedicated equipment. The small set of servers at the endpoints used a combination of 10GE and 40GE technologies, and SSD drives for data storage. The configuration of the network and the server configuration are discussed. We will show that the system was able to achieve disk-to-disk transfer rates of 60 Gbps and memory-to-memory rates in excess of 180 Gbps across the WAN. We will discuss the transfer tools, disk configurations, and monitoring tools used in the demonstration.

  10. Disk-to-Disk network transfers at 100 Gb/s

    International Nuclear Information System (INIS)

    Barczyk, Artur; Legrand, Iosif; Mughal, Azher; Newman, Harvey; Rozsa, Sandor; Voicu, Ramiro; Gable, Ian; Leavett-Brown, Colin; Lewall, Kim; Savard, Yvan; Sobie, Randall J; Hay, Marilyn; McWilliam, Donald; McKee, Shawn; Tam, Thomas

    2012-01-01

    A 100 Gbps network was established between the California Institute of Technology conference booth at the Super Computing 2011 conference in Seattle, Washington and the computing center at the University of Victoria in Canada. A circuit was established over the BCNET, CANARIE and Super Computing (SCInet) networks using dedicated equipment. The small set of servers at the endpoints used a combination of 10GE and 40GE technologies, and SSD drives for data storage. The configuration of the network and the server configuration are discussed. We will show that the system was able to achieve disk-to-disk transfer rates of 60 Gbps and memory-to-memory rates in excess of 180 Gbps across the WAN. We will discuss the transfer tools, disk configurations, and monitoring tools used in the demonstration.

  11. MODELING DUST EMISSION OF HL TAU DISK BASED ON PLANET–DISK INTERACTIONS

    International Nuclear Information System (INIS)

    Jin, Sheng; Ji, Jianghui; Li, Shengtai; Li, Hui; Isella, Andrea

    2016-01-01

    We use extensive global two-dimensional hydrodynamic disk gas+dust simulations with embedded planets, coupled with three-dimensional radiative transfer calculations, to model the dust ring and gap structures in the HL Tau protoplanetary disk observed with the Atacama Large Millimeter/Submillimeter Array (ALMA). We include the self-gravity of disk gas and dust components and make reasonable choices of disk parameters, assuming an already settled dust distribution and no planet migration. We can obtain quite adequate fits to the observed dust emission using three planets with masses of 0.35, 0.17, and 0.26 M Jup at 13.1, 33.0, and 68.6 AU, respectively. Implications for the planet formation as well as the limitations of this scenario are discussed

  12. Relationships between Paraspinal Muscle Activity and Lumbar Inter-Vertebral Range of Motion

    OpenAIRE

    du Rose, Alister; Breen, Alan

    2016-01-01

    Abstract: Control of the lumbar spine requires contributions from both the active and passive sub-systems. Identifying interactions between these systems may provide insight into the mechanisms of low back pain. However, as a first step it is important to investigate what is normal. The purpose of this study was to explore the relationships between the lumbar inter-vertebral range of motion and paraspinal muscle activity during weight-bearing flexion in healthy controls using quantitative flu...

  13. Fast disk array for image storage

    Science.gov (United States)

    Feng, Dan; Zhu, Zhichun; Jin, Hai; Zhang, Jiangling

    1997-01-01

    A fast disk array is designed for the large continuous image storage. It includes a high speed data architecture and the technology of data striping and organization on the disk array. The high speed data path which is constructed by two dual port RAM and some control circuit is configured to transfer data between a host system and a plurality of disk drives. The bandwidth can be more than 100 MB/s if the data path based on PCI (peripheral component interconnect). The organization of data stored on the disk array is similar to RAID 4. Data are striped on a plurality of disk, and each striping unit is equal to a track. I/O instructions are performed in parallel on the disk drives. An independent disk is used to store the parity information in the fast disk array architecture. By placing the parity generation circuit directly on the SCSI (or SCSI 2) bus, the parity information can be generated on the fly. It will affect little on the data writing in parallel on the other disks. The fast disk array architecture designed in the paper can meet the demands of the image storage.

  14. Bovine annulus fibrosus cell lines isolated from intervertebral discs

    Directory of Open Access Journals (Sweden)

    Petra Kraus

    2016-12-01

    Full Text Available The adult bovine (Bos taurus intervertebral disc is primarily comprised of two major tissue types: The outer annulus fibrosus (AF and the central nucleus pulposus (NP. We isolated several primary cell lineages of passage (P 0 cells from the AF tissue omitting typically used enzymatic tissue digestion protocols. The cells grow past p10 without signs of senescence in DMEM + 10% FCS on 0.1% gelatin coated/uncoated surfaces of standard cell culture plates and survive freeze-thawing. Preliminary analysis of the AF derived cells for expression of the two structural genes Col1a1 and Col2a1 was performed by PISH recapitulating the expression observed in vivo.

  15. Debris Disks in Aggregate: Using Hubble Space Telescope Coronagraphic Imagery to Understand the Scattered-Light Disk Detection Rate

    Science.gov (United States)

    Grady, Carol A.

    2011-01-01

    Despite more than a decade of coronagraphic imaging of debris disk candidate stars, only 16 have been imaged in scattered light. Since imaged disks provide our best insight into processes which sculpt disks, and can provide signposts of the presence of giant planets at distances which would elude radial velocity and transit surveys, we need to understand under what conditions we detect the disks in scattered light, how these disks differ from the majority of debris disks, and how to increase the yield of disks which are imaged with 0.1" angular resolution. In this talk, I will review what we have learned from a shallow HSTINICMOS NIR survey of debris disks, and present first results from our on-going HST /STIS optical imaging of bright scattered-light disks.

  16. Coevolution of Binaries and Circumbinary Gaseous Disks

    Science.gov (United States)

    Fleming, David; Quinn, Thomas R.

    2018-04-01

    The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disk, and how the disk and binary interact. The central binary excites resonances in the surrounding protoplanetary disk that drive evolution in both the binary orbital elements and in the disk. To probe how these interactions impact both binary eccentricity and disk structure evolution, we ran N-body smooth particle hydrodynamics (SPH) simulations of gaseous protoplanetary disks surrounding binaries based on Kepler 38 for 10^4 binary orbital periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disk via a parametric instability and excite disk eccentricity growth. Eccentric binaries strongly couple to the disk causing eccentricity growth for both the disk and binary. Disks around sufficiently eccentric binaries strongly couple to the disk and develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance (EOLR). This wave corresponds to an alignment of gas particle longitude of periastrons. We find that in all simulations, the binary semi-major axis decays due to dissipation from the viscous disk.

  17. An experimental study of percutaneous laser nucleotomy of the intervertebral cervical disc

    International Nuclear Information System (INIS)

    Wang Yiqing; Wang Zhimin; Guo Weiping; Zhang Hongxin; Guan Yan; Li Wenxian; Ni Daihui

    2002-01-01

    Objective: To study the effectiveness and safety of laser nucleotomy of the intervertebral cervical disc. Methods: The experimental study was performed in 10 dogs, and each dog was treated with laser nucleolysis in C3-4 and C4-5. The laser energy was turned on in 1.0-second pulses with 1.0 second (C3-4) and 5.0 second (C4-5) pause interval, and the total energy was up to 1000 joules. The temperatures were measured at the place between the posterior longitudinal ligament and the dura and at the vertebral foramen by using a tip type thermometer. Chronic histologic changes were observed by light microscopy at 2-4 weeks after laser irradiation. Results: The temperatures at the place between the posterior longitudinal ligament and the dura and at the vertebral Forman did not exceed 40 degree C when the pause interval was 5 second. Two dogs were euthanized immediately after treatment, and the oval-shaped cavity was observed on the macroscopic view in the nucleus. The cavity measured between 5 mm and 6 mm in long axis and between 2 mm and 4 mm in short. 4 weeks after the laser irradiation, the nucleus pulposus was replaced by cartilaginous cells and fibrous tissues. Conclusion: The laser nucleotomy of the intervertebral cervical disc is effective and feasible at the suitable condition

  18. Effect of Capsaicin Cream on Chronic Low Back Pain in Patients With Inter-Vertebral Disc Herniation

    Directory of Open Access Journals (Sweden)

    Fayazi

    2015-07-01

    Full Text Available Background Low back pain is one of the most common debilitating disorders worldwide and the third cause of visiting a physician. One of the most common causes of low back pain is spinal disc herniation. Still there is no general agreement on the most effective treatment for it. Objectives This study aimed to determine the effect of Capsaicin cream on low back pain in patients with inter-vertebral disc herniation in Ahvaz. Patients and Methods This was a double blind clinical trial in which 43 patients with chronic low back pain, according to characteristics of the subjects, were randomly divided into two groups of treatment (n = 23 and control (n = 20. Data collection instruments included demographic specifications and visual analogue scale (VAS questionnaire completed on arrival and at the first, second and third weeks after intervention. The treatment and placebo groups used the ointment for three weeks and three times a day as a thin layer on the painful position. Data entered SPSS (version 18 and analyzed using the analytical descriptive statistics. Results There was a significant difference in the average pain intensity between the groups of study pre-and post-intervention (P = 0.0001 and the rate of using analgesics in the treatment group significantly decreased (P = 0.008. Also patients’ satisfaction was significantly different between the two groups using the ointment (P = 0.0001. Conclusions Capsaicin cream has beneficial effects on pain relieving and reducing analgesic use in patients with inter-vertebral disc herniation. Therefore, the ointment can be recommended in the treatment of low back pain caused by inter-vertebral disc herniation.

  19. MOLECULAR GAS IN YOUNG DEBRIS DISKS

    International Nuclear Information System (INIS)

    Moor, A.; Abraham, P.; Kiss, Cs.; Juhasz, A.; Kospal, A.; Pascucci, I.; Apai, D.; Henning, Th.; Csengeri, T.; Grady, C.

    2011-01-01

    Gas-rich primordial disks and tenuous gas-poor debris disks are usually considered as two distinct evolutionary phases of the circumstellar matter. Interestingly, the debris disk around the young main-sequence star 49 Ceti possesses a substantial amount of molecular gas and possibly represents the missing link between the two phases. Motivated to understand the evolution of the gas component in circumstellar disks via finding more 49 Ceti-like systems, we carried out a CO J = 3-2 survey with the Atacama Pathfinder EXperiment, targeting 20 infrared-luminous debris disks. These systems fill the gap between primordial and old tenuous debris disks in terms of fractional luminosity. Here we report on the discovery of a second 49 Ceti-like disk around the 30 Myr old A3-type star HD21997, a member of the Columba Association. This system was also detected in the CO(2-1) transition, and the reliable age determination makes it an even clearer example of an old gas-bearing disk than 49 Ceti. While the fractional luminosities of HD21997 and 49 Ceti are not particularly high, these objects seem to harbor the most extended disks within our sample. The double-peaked profiles of HD21997 were reproduced by a Keplerian disk model combined with the LIME radiative transfer code. Based on their similarities, 49 Ceti and HD21997 may be the first representatives of a so far undefined new class of relatively old (∼>8 Myr), gaseous dust disks. From our results, neither primordial origin nor steady secondary production from icy planetesimals can unequivocally explain the presence of CO gas in the disk of HD21997.

  20. Deformation and Life Analysis of Composite Flywheel Disk and Multi-disk Systems

    Science.gov (United States)

    Arnold, S. M.; Saleeb, A. F.; AlZoubi, N. R.

    2001-01-01

    In this study an attempt is made to put into perspective the problem of a rotating disk, be it a single disk or a number of concentric disks forming a unit. An analytical model capable of performing an elastic stress analysis for single/multiple, annular/solid, anisotropic/isotropic disk systems, subjected to both pressure surface tractions, body forces (in the form of temperature-changes and rotation fields) and interfacial misfits is derived and discussed. Results of an extensive parametric study are presented to clearly define the key design variables and their associated influence. In general the important parameters were identified as misfit, mean radius, thickness, material property and/or load gradation, and speed; all of which must be simultaneously optimized to achieve the "best" and most reliable design. Also, the important issue of defining proper performance/merit indices (based on the specific stored energy), in the presence of multiaxiality and material anisotropy is addressed. These merit indices are then utilized to discuss the difference between flywheels made from PMC and TMC materials with either an annular or solid geometry. Finally two major aspects of failure analysis, that is the static and cyclic limit (burst) speeds are addressed. In the case of static limit loads, upper, lower, and out-of-plane bounds for disks with constant thickness are presented for both the case of internal pressure loading (as one would see in a hydroburst test) and pure rotation (as in the case of a free spinning disk). The results (interaction diagrams) are displayed graphically in designer friendly format. For the case of fatigue, a representative fatigue/life master curve is illustrated in which the normalized limit speed versus number of applied cycles is given for a cladded TMC disk application.

  1. FOMALHAUT'S DEBRIS DISK AND PLANET: CONSTRAINING THE MASS OF FOMALHAUT B FROM DISK MORPHOLOGY

    International Nuclear Information System (INIS)

    Chiang, E.; Kalas, P.; Graham, J. R.; Kite, E.; Clampin, M.

    2009-01-01

    Following the optical imaging of exoplanet candidate Fomalhaut b (Fom b), we present a numerical model of how Fomalhaut's debris disk is gravitationally shaped by a single interior planet. The model is simple, adaptable to other debris disks, and can be extended to accommodate multiple planets. If Fom b is the dominant perturber of the belt, then to produce the observed disk morphology it must have a mass M pl J , an orbital semimajor axis a pl > 101.5 AU, and an orbital eccentricity e pl = 0.11-0.13. These conclusions are independent of Fom b's photometry. To not disrupt the disk, a greater mass for Fom b demands a smaller orbit farther removed from the disk; thus, future astrometric measurement of Fom b's orbit, combined with our model of planet-disk interaction, can be used to determine the mass more precisely. The inner edge of the debris disk at a ∼ 133 AU lies at the periphery of Fom b's chaotic zone, and the mean disk eccentricity of e ∼ 0.11 is secularly forced by the planet, supporting predictions made prior to the discovery of Fom b. However, previous mass constraints based on disk morphology rely on several oversimplifications. We explain why our constraint is more reliable. It is based on a global model of the disk that is not restricted to the planet's chaotic zone boundary. Moreover, we screen disk parent bodies for dynamical stability over the system age of ∼ 100 Myr, and model them separately from their dust grain progeny; the latter's orbits are strongly affected by radiation pressure and their lifetimes are limited to ∼ 0.1 Myr by destructive grain-grain collisions. The single planet model predicts that planet and disk orbits be apsidally aligned. Fomalhaut b's nominal space velocity does not bear this out, but the astrometric uncertainties may be large. If the apsidal misalignment proves real, our calculated upper mass limit of 3M J still holds. If the orbits are aligned, our model predicts M pl = 0.5M J , a pl = 115 AU, and e pl = 0

  2. Experimental substantiation and clinical use of functional pneumoepidurography in the diagnosis of lumbar osteochondrosis i

    Energy Technology Data Exchange (ETDEWEB)

    Sharov, B.K.; Plekhanov, L.G. (Chelyabinskij Meditsinskij Inst. (USSR))

    Anatomic and X-ray correlations in 31 postmortem unfixed specimens of the vertebral lumbar region have shown that in the diagnosis of disk prolapse and commissural processes in the anterior epidural space roentgenopositive contrast substances are not much superior to roentgenonegative ones. Functional pneumoepidurogaphy used in 102 patients with lumbar osteochondrosis helped to reveal intervertebral disk prolapse at all the stages of degenerative affection, to evaluate function of the disk-ligamentous apparatus and to specify the nature of a pathological process in the epidural space.

  3. DISCOVERY OF AN EDGE-ON DEBRIS DISK WITH A DUST RING AND AN OUTER DISK WING-TILT ASYMMETRY

    International Nuclear Information System (INIS)

    Kasper, Markus; Apai, Dániel; Wagner, Kevin; Robberto, Massimo

    2015-01-01

    Using Very Large Telescope/SPHERE near-infrared dual-band imaging and integral field spectroscopy, we discovered an edge-on debris disk around the 17 Myr old A-type member of the Scorpius–Centaurus OB association HD 110058. The edge-on disk can be traced to about 0.″6 or 65 AU projected separation. In its northern and southern wings, the disk shows at all wavelengths two prominent, bright, and symmetrically placed knots at 0.″3 or 32 AU from the star. We interpret these knots as a ring of planetesimals whose collisions may produce most of the dust observed in the disk. We find no evidence for a bow in the disk, but we identify a pair of symmetric, hooklike features in both wings. Based on similar features in the Beta Pictoris disk, we propose that this wing-tilt asymmetry traces either an outer planetesimal belt that is inclined with respect to the disk midplane or radiation-pressure-driven dust blown out from a yet unseen inner belt that is inclined with respect to the disk midplane. The misaligned inner or outer disk may be a result of interaction with a yet unseen planet. Overall, the disk geometry resembles the nearby disk around Beta Pictoris, albeit seen at smaller radial scales

  4. CIRCUMSTELLAR DEBRIS DISKS: DIAGNOSING THE UNSEEN PERTURBER

    Energy Technology Data Exchange (ETDEWEB)

    Nesvold, Erika R. [Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Rd., Washington, DC 20015 (United States); Naoz, Smadar; Vican, Laura [Department of Physics and Astronomy, UCLA, 475 Portola Plaza, Los Angeles, CA 90095 (United States); Farr, Will M. [School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT (United Kingdom)

    2016-07-20

    The first indication of the presence of a circumstellar debris disk is usually the detection of excess infrared emission from the population of small dust grains orbiting the star. This dust is short-lived, requiring continual replenishment, and indicating that the disk must be excited by an unseen perturber. Previous theoretical studies have demonstrated that an eccentric planet orbiting interior to the disk will stir the larger bodies in the belt and produce dust via interparticle collisions. However, motivated by recent observations, we explore another possible mechanism for heating a debris disk: a stellar-mass perturber orbiting exterior to and inclined to the disk and exciting the disk particles’ eccentricities and inclinations via the Kozai–Lidov mechanism. We explore the consequences of an exterior perturber on the evolution of a debris disk using secular analysis and collisional N -body simulations. We demonstrate that a Kozai–Lidov excited disk can generate a dust disk via collisions and we compare the results of the Kozai–Lidov excited disk with a simulated disk perturbed by an interior eccentric planet. Finally, we propose two observational tests of a dust disk that can distinguish whether the dust was produced by an exterior brown dwarf or stellar companion or an interior eccentric planet.

  5. Image processing techniques applied to the detection of optic disk: a comparison

    Science.gov (United States)

    Kumari, Vijaya V.; Narayanan, Suriya N.

    2010-02-01

    In retinal image analysis, the detection of optic disk is of paramount importance. It facilitates the tracking of various anatomical features and also in the extraction of exudates, drusens etc., present in the retina of human eye. The health of retina crumbles with age in some people during the presence of exudates causing Diabetic Retinopathy. The existence of exudates increases the risk for age related macular Degeneration (AMRD) and it is the leading cause for blindness in people above the age of 50.A prompt diagnosis when the disease is at the early stage can help to prevent irreversible damages to the diabetic eye. Screening to detect diabetic retinopathy helps to prevent the visual loss. The optic disk detection is the rudimentary requirement for the screening. In this paper few methods for optic disk detection were compared which uses both the properties of optic disk and model based approaches. They are uniquely used to give accurate results in the retinal images.

  6. Are animal models useful for studying human disc disorders / degeneration?

    NARCIS (Netherlands)

    Alini, M.; Eisenstein, S.M.; Ito, K.; Little, C.; Kettler, A.A.; Masuda, K.; Melrose, J.; Ralphs, J.; Stokes, I.; Wilke, H.J.

    2008-01-01

    Intervertebral disc (IVD) degeneration is an often investigated pathophysiological condition because of its implication in causing low back pain. As human material for such studies is difficult to obtain because of ethical and government regulatory restriction, animal tissue, organs and in vivo

  7. Circumstellar and circumplanetary disks

    Science.gov (United States)

    Chiang, Eugene

    2000-11-01

    This thesis studies disks in three astrophysical contexts: (1)protoplanetary disks; (2)the Edgeworth-Kuiper Belt; and (3)planetary rings. We derive hydrostatic, radiative equilibrium models of passive protoplanetary disks surrounding T Tauri and Herbig Ae/Be stars. Each disk is encased by an optically thin layer of superheated dust grains. This layer is responsible for up to ~70% of the disk luminosity at wavelengths between ~5 and 60 μm. The heated disk flares and absorbs more stellar radiation at a given stellocentric distance than a flat disk would. Spectral energy distributions are computed and found to compare favorably with the observed flattish infrared excesses of several young stellar objects. Spectral features from dust grains in the superheated layer appear in emission if the disk is viewed nearly face-on. We present the results of a pencil-beam survey of the Kuiper Belt using the Keck 10-m telescope. Two new objects are discovered. Data from all surveys are pooled to construct the luminosity function from mR = 20 to 27. The cumulative number of objects per square degree, Σ(surface area but the largest bodies contain most of the mass. To order-of-magnitude, 0.2 M⊕ and 1 × 1010 comet progenitors lie between 30 and 50 AU. The classical Kuiper Belt appears truncated at a distance of 50 AU. We propose that rigid precession of narrow eccentric planetary rings surrounding Uranus and Saturn is maintained by a balance of forces due to ring self- gravity, planetary oblateness, and interparticle collisions. Collisional impulses play an especially dramatic role near ring edges. Pressure-induced accelerations are maximal near edges because there (1)velocity dispersions are enhanced by resonant satellite perturbations, and (2)the surface density declines steeply. Remarkably, collisional forces felt by material in the last ~100 m of a ~10 km wide ring can increase equilibrium masses up to a factor of ~100. New ring surface densities are derived which accord with

  8. Head-Disk Interface Technology: Challenges and Approaches

    Science.gov (United States)

    Liu, Bo

    Magnetic hard disk drive (HDD) technology is believed to be one of the most successful examples of modern mechatronics systems. The mechanical beauty of magnetic HDD includes simple but super high accuracy positioning head, positioning technology, high speed and stability spindle motor technology, and head-disk interface technology which keeps the millimeter sized slider flying over a disk surface at nanometer level slider-disk spacing. This paper addresses the challenges and possible approaches on how to further reduce the slider disk spacing whilst retaining the stability and robustness level of head-disk systems for future advanced magnetic disk drives.

  9. Fluid flow and convective transport of solutes within the intervertebral disc.

    Science.gov (United States)

    Ferguson, Stephen J; Ito, Keita; Nolte, Lutz P

    2004-02-01

    Previous experimental and analytical studies of solute transport in the intervertebral disc have demonstrated that for small molecules diffusive transport alone fulfils the nutritional needs of disc cells. It has been often suggested that fluid flow into and within the disc may enhance the transport of larger molecules. The goal of the study was to predict the influence of load-induced interstitial fluid flow on mass transport in the intervertebral disc. An iterative procedure was used to predict the convective transport of physiologically relevant molecules within the disc. An axisymmetric, poroelastic finite-element structural model of the disc was developed. The diurnal loading was divided into discrete time steps. At each time step, the fluid flow within the disc due to compression or swelling was calculated. A sequentially coupled diffusion/convection model was then employed to calculate solute transport, with a constant concentration of solute being provided at the vascularised endplates and outer annulus. Loading was simulated for a complete diurnal cycle, and the relative convective and diffusive transport was compared for solutes with molecular weights ranging from 400 Da to 40 kDa. Consistent with previous studies, fluid flow did not enhance the transport of low-weight solutes. During swelling, interstitial fluid flow increased the unidirectional penetration of large solutes by approximately 100%. Due to the bi-directional temporal nature of disc loading, however, the net effect of convective transport over a full diurnal cycle was more limited (30% increase). Further study is required to determine the significance of large solutes and the timing of their delivery for disc physiology.

  10. Cadaveric Study of Male Lumbar Intervertebral Foramina Morphometry in Ile-Ife

    Directory of Open Access Journals (Sweden)

    Sunday E. C

    2018-04-01

    Full Text Available Background: This study was designed to investigate the mean lumbar foramina height and length in male cadaveric specimens in Ile-Ife. Aim and Objectives: Two hundred and fifty intervertebral foramina derived from twenty-five male cadaveric specimens were analyzed, were studied. They were obtained from the Department of Anatomy, Obafemi Awolowo University, Ile-Ife, Osun State in Southwestern Nigeria. The cadavers were positioned prone and a routine paraspinal approach was employed to gain exposure to the posterior spinal element following meticulous soft tissue dissection. An osteotomy of the iliac crest was performed to adequately expose the fifth lumbar (L1-S1 foramina.Parameters assessed were; the foramen height and the foraminal length. The measurement was performed three times on each side using vernier calipers. The variations of the different measurements in the cephalo-caudal direction were analyzed for statistical differences using the “One way ANOVA” with post hoc test. Results: The result showed a gradual increase of the foramina height were observed on both right and left side from L1-L2 to L3- L4 and from then on decreased progressively towards the L5-S1 level. No statistical difference was noted in the measurements derived (p<0.05. Conclusion: A good understanding of the lumbar intervertebral foraminal are essential in surgical planning of suitably sized cannulas necessary for less invasive spine surgeries as well as help in diagnosis of pathologies surrounding this important region following adequate clinical evaluation and measurements using imaging.

  11. An Optimal Strategy for Accurate Bulge-to-disk Decomposition of Disk Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Gao Hua [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

    2017-08-20

    The development of two-dimensional (2D) bulge-to-disk decomposition techniques has shown their advantages over traditional one-dimensional (1D) techniques, especially for galaxies with non-axisymmetric features. However, the full potential of 2D techniques has yet to be fully exploited. Secondary morphological features in nearby disk galaxies, such as bars, lenses, rings, disk breaks, and spiral arms, are seldom accounted for in 2D image decompositions, even though some image-fitting codes, such as GALFIT, are capable of handling them. We present detailed, 2D multi-model and multi-component decomposition of high-quality R -band images of a representative sample of nearby disk galaxies selected from the Carnegie-Irvine Galaxy Survey, using the latest version of GALFIT. The sample consists of five barred and five unbarred galaxies, spanning Hubble types from S0 to Sc. Traditional 1D decomposition is also presented for comparison. In detailed case studies of the 10 galaxies, we successfully model the secondary morphological features. Through a comparison of best-fit parameters obtained from different input surface brightness models, we identify morphological features that significantly impact bulge measurements. We show that nuclear and inner lenses/rings and disk breaks must be properly taken into account to obtain accurate bulge parameters, whereas outer lenses/rings and spiral arms have a negligible effect. We provide an optimal strategy to measure bulge parameters of typical disk galaxies, as well as prescriptions to estimate realistic uncertainties of them, which will benefit subsequent decomposition of a larger galaxy sample.

  12. An Optimal Strategy for Accurate Bulge-to-disk Decomposition of Disk Galaxies

    Science.gov (United States)

    Gao, Hua; Ho, Luis C.

    2017-08-01

    The development of two-dimensional (2D) bulge-to-disk decomposition techniques has shown their advantages over traditional one-dimensional (1D) techniques, especially for galaxies with non-axisymmetric features. However, the full potential of 2D techniques has yet to be fully exploited. Secondary morphological features in nearby disk galaxies, such as bars, lenses, rings, disk breaks, and spiral arms, are seldom accounted for in 2D image decompositions, even though some image-fitting codes, such as GALFIT, are capable of handling them. We present detailed, 2D multi-model and multi-component decomposition of high-quality R-band images of a representative sample of nearby disk galaxies selected from the Carnegie-Irvine Galaxy Survey, using the latest version of GALFIT. The sample consists of five barred and five unbarred galaxies, spanning Hubble types from S0 to Sc. Traditional 1D decomposition is also presented for comparison. In detailed case studies of the 10 galaxies, we successfully model the secondary morphological features. Through a comparison of best-fit parameters obtained from different input surface brightness models, we identify morphological features that significantly impact bulge measurements. We show that nuclear and inner lenses/rings and disk breaks must be properly taken into account to obtain accurate bulge parameters, whereas outer lenses/rings and spiral arms have a negligible effect. We provide an optimal strategy to measure bulge parameters of typical disk galaxies, as well as prescriptions to estimate realistic uncertainties of them, which will benefit subsequent decomposition of a larger galaxy sample.

  13. An Optimal Strategy for Accurate Bulge-to-disk Decomposition of Disk Galaxies

    International Nuclear Information System (INIS)

    Gao Hua; Ho, Luis C.

    2017-01-01

    The development of two-dimensional (2D) bulge-to-disk decomposition techniques has shown their advantages over traditional one-dimensional (1D) techniques, especially for galaxies with non-axisymmetric features. However, the full potential of 2D techniques has yet to be fully exploited. Secondary morphological features in nearby disk galaxies, such as bars, lenses, rings, disk breaks, and spiral arms, are seldom accounted for in 2D image decompositions, even though some image-fitting codes, such as GALFIT, are capable of handling them. We present detailed, 2D multi-model and multi-component decomposition of high-quality R -band images of a representative sample of nearby disk galaxies selected from the Carnegie-Irvine Galaxy Survey, using the latest version of GALFIT. The sample consists of five barred and five unbarred galaxies, spanning Hubble types from S0 to Sc. Traditional 1D decomposition is also presented for comparison. In detailed case studies of the 10 galaxies, we successfully model the secondary morphological features. Through a comparison of best-fit parameters obtained from different input surface brightness models, we identify morphological features that significantly impact bulge measurements. We show that nuclear and inner lenses/rings and disk breaks must be properly taken into account to obtain accurate bulge parameters, whereas outer lenses/rings and spiral arms have a negligible effect. We provide an optimal strategy to measure bulge parameters of typical disk galaxies, as well as prescriptions to estimate realistic uncertainties of them, which will benefit subsequent decomposition of a larger galaxy sample.

  14. Foundations of Black Hole Accretion Disk Theory

    Directory of Open Access Journals (Sweden)

    Marek A. Abramowicz

    2013-01-01

    Full Text Available This review covers the main aspects of black hole accretion disk theory. We begin with the view that one of the main goals of the theory is to better understand the nature of black holes themselves. In this light we discuss how accretion disks might reveal some of the unique signatures of strong gravity: the event horizon, the innermost stable circular orbit, and the ergosphere. We then review, from a first-principles perspective, the physical processes at play in accretion disks. This leads us to the four primary accretion disk models that we review: Polish doughnuts (thick disks, Shakura-Sunyaev (thin disks, slim disks, and advection-dominated accretion flows (ADAFs. After presenting the models we discuss issues of stability, oscillations, and jets. Following our review of the analytic work, we take a parallel approach in reviewing numerical studies of black hole accretion disks. We finish with a few select applications that highlight particular astrophysical applications: measurements of black hole mass and spin, black hole vs. neutron star accretion disks, black hole accretion disk spectral states, and quasi-periodic oscillations (QPOs.

  15. Foundations of Black Hole Accretion Disk Theory.

    Science.gov (United States)

    Abramowicz, Marek A; Fragile, P Chris

    2013-01-01

    This review covers the main aspects of black hole accretion disk theory. We begin with the view that one of the main goals of the theory is to better understand the nature of black holes themselves. In this light we discuss how accretion disks might reveal some of the unique signatures of strong gravity: the event horizon, the innermost stable circular orbit, and the ergosphere. We then review, from a first-principles perspective, the physical processes at play in accretion disks. This leads us to the four primary accretion disk models that we review: Polish doughnuts (thick disks), Shakura-Sunyaev (thin) disks, slim disks, and advection-dominated accretion flows (ADAFs). After presenting the models we discuss issues of stability, oscillations, and jets. Following our review of the analytic work, we take a parallel approach in reviewing numerical studies of black hole accretion disks. We finish with a few select applications that highlight particular astrophysical applications: measurements of black hole mass and spin, black hole vs. neutron star accretion disks, black hole accretion disk spectral states, and quasi-periodic oscillations (QPOs).

  16. Short term outcome of posterior dynamic stabilization system in degenerative lumbar diseases

    Directory of Open Access Journals (Sweden)

    Mingyuan Yang

    2014-01-01

    Conclusion: Dynamic stabilization system treating lumbar degenerative disease showed clinical benefits with motion preservation of the operated segments, but does not have the significant advantage on motion preservation at adjacent segments, to avoid the degeneration of adjacent intervertebral disk.

  17. Relativistic, accreting disks

    International Nuclear Information System (INIS)

    Abramowicz, M.A; Jaroszynski, M.; Sikora, M.

    1978-01-01

    An analytic theory of the hydrodynamical structure of accreting disks (without self-gravitation but with pressure) orbiting around and axially symmetric, stationary, compact body (e.g. black hole) is presented. The inner edge of the marginally stable accreting disk (i.e. disk with constant angular momentum density) has a sharp cusp located on the equatorial plane between rsub(ms) and rsub(mb). The existence of the cusp is also typical for any angular momentum distribution. The physical importance of the cusp follows from the close analogy with the case of a close binary system (L 1 Lagrange point on the Roche lobe). The existence of the cusp is thus a crucial phenomenon in such problems as boundary condition for the viscous stresses, accretion rate etc. (orig.) [de

  18. MRI T2* mapping correlates with biochemistry and histology in intervertebral disc degeneration in a large animal model

    NARCIS (Netherlands)

    Detiger, Suzanne E. L.; Holewijn, Roderick M.; Hoogendoorn, Roel J. W.; van Royen, Barend J.; Helder, Marco N.; Berger, Ferco H.; Kuijer, Joost P. A.; Smit, Theo H.

    2015-01-01

    To evaluate intervertebral disc (IVD) degeneration and treatments, an objective diagnostic tool is needed. Recently, T2* relaxation time mapping was proposed as a technique to assess early IVD degeneration, yet the correlation with biochemical content and histological features has not been

  19. MRI T2* mapping correlates with biochemistry and histology in intervertebral disc degeneration in a large animal model

    NARCIS (Netherlands)

    Detiger, S.E.L.; Holewijn, R.M.; Hoogendoorn, R.J.W.; van Royen, B.J.; Helder, M.N.; Berger, F.H.; Kuijer, J.P.A.; Smit, T.H.

    2015-01-01

    Purpose: To evaluate intervertebral disc (IVD) degeneration and treatments, an objective diagnostic tool is needed. Recently, T2* relaxation time mapping was proposed as a technique to assess early IVD degeneration, yet the correlation with biochemical content and histological features has not been

  20. Grain surface chemistry in protoplanetary disks

    International Nuclear Information System (INIS)

    Reboussin, Laura

    2015-01-01

    Planetary formation occurs in the protoplanetary disks of gas and dust. Although dust represents only 1% of the total disk mass, it plays a fundamental role in disk chemical evolution since it acts as a catalyst for the formation of molecules. Understanding this chemistry is therefore essential to determine the initial conditions from which planets form. During my thesis, I studied grain-surface chemistry and its impact on the chemical evolution of molecular cloud, initial condition for disk formation, and protoplanetary disk. Thanks to numerical simulations, using the gas-grain code Nautilus, I showed the importance of diffusion reactions and gas-grain interactions for the abundances of gas-phase species. Model results combined with observations also showed the effects of the physical structure (in temperature, density, AV) on the molecular distribution in disks. (author)

  1. The DiskMass Survey. II. Error Budget

    Science.gov (United States)

    Bershady, Matthew A.; Verheijen, Marc A. W.; Westfall, Kyle B.; Andersen, David R.; Swaters, Rob A.; Martinsson, Thomas

    2010-06-01

    We present a performance analysis of the DiskMass Survey. The survey uses collisionless tracers in the form of disk stars to measure the surface density of spiral disks, to provide an absolute calibration of the stellar mass-to-light ratio (Υ_{*}), and to yield robust estimates of the dark-matter halo density profile in the inner regions of galaxies. We find that a disk inclination range of 25°-35° is optimal for our measurements, consistent with our survey design to select nearly face-on galaxies. Uncertainties in disk scale heights are significant, but can be estimated from radial scale lengths to 25% now, and more precisely in the future. We detail the spectroscopic analysis used to derive line-of-sight velocity dispersions, precise at low surface-brightness, and accurate in the presence of composite stellar populations. Our methods take full advantage of large-grasp integral-field spectroscopy and an extensive library of observed stars. We show that the baryon-to-total mass fraction ({F}_bar) is not a well-defined observational quantity because it is coupled to the halo mass model. This remains true even when the disk mass is known and spatially extended rotation curves are available. In contrast, the fraction of the rotation speed supplied by the disk at 2.2 scale lengths (disk maximality) is a robust observational indicator of the baryonic disk contribution to the potential. We construct the error budget for the key quantities: dynamical disk mass surface density (Σdyn), disk stellar mass-to-light ratio (Υ^disk_{*}), and disk maximality ({F}_{*,max}^disk≡ V^disk_{*,max}/ V_c). Random and systematic errors in these quantities for individual galaxies will be ~25%, while survey precision for sample quartiles are reduced to 10%, largely devoid of systematic errors outside of distance uncertainties.

  2. A COMMON SOURCE OF ACCRETION DISK TILT

    International Nuclear Information System (INIS)

    Montgomery, M. M.; Martin, E. L.

    2010-01-01

    Many different system types retrogradely precess, and retrograde precession could be from a tidal torque by the secondary on a misaligned accretion disk. However, a source that causes and maintains disk tilt is unknown. In this work, we show that accretion disks can tilt due to a force called lift. Lift results from differing gas stream supersonic speeds over and under an accretion disk. Because lift acts at the disk's center of pressure, a torque is applied around a rotation axis passing through the disk's center of mass. The disk responds to lift by pitching around the disk's line of nodes. If the gas stream flow ebbs, then lift also ebbs and the disk attempts to return to its original orientation. To first approximation, lift does not depend on magnetic fields or radiation sources but does depend on the mass and the surface area of the disk. Also, for disk tilt to be initiated, a minimum mass transfer rate must be exceeded. For example, a 10 -11 M sun disk around a 0.8 M sun compact central object requires a mass transfer rate greater than ∼ 8 x 10 -11 M sun yr -1 , a value well below the known mass transfer rates in cataclysmic variable dwarf novae systems that retrogradely precess and exhibit negative superhumps in their light curves and a value well below mass transfer rates in protostellar-forming systems.

  3. Contribution of collagen fibers to the compressive stiffness of cartilaginous tissues

    NARCIS (Netherlands)

    Römgens, A.M.; Donkelaar, van C.C.; Ito, K.

    2013-01-01

    Cartilaginous tissues such as the intervertebral disk are predominantly loaded under compression. Yet, they contain abundant collagen fibers, which are generally assumed to contribute to tensile loading only. Fiber tension is thought to originate from swelling of the proteoglycan-rich nucleus.

  4. Covering and piercing disks with two centers

    KAUST Repository

    Ahn, Heekap; Kim, Sangsub; Knauer, Christian; Schlipf, Lena; Shin, Chansu; Vigneron, Antoine E.

    2013-01-01

    We give exact and approximation algorithms for two-center problems when the input is a set D of disks in the plane. We first study the problem of finding two smallest congruent disks such that each disk in D intersects one of these two disks. Then we study the problem of covering the set D by two smallest congruent disks. © 2012 Elsevier B.V.

  5. Covering and piercing disks with two centers

    KAUST Repository

    Ahn, Heekap

    2013-04-01

    We give exact and approximation algorithms for two-center problems when the input is a set D of disks in the plane. We first study the problem of finding two smallest congruent disks such that each disk in D intersects one of these two disks. Then we study the problem of covering the set D by two smallest congruent disks. © 2012 Elsevier B.V.

  6. HERSCHEL OBSERVATIONS OF THE T CHA TRANSITION DISK: CONSTRAINING THE OUTER DISK PROPERTIES

    OpenAIRE

    Cieza, Lucas A.; Olofsson, Johan; Harvey, Paul M.; Pinte, Christophe; Merin, Bruno; Augereau, Jean-Charles; Evans, Neal J., II; Najita, Joan; Henning, Thomas; Menard, Francois

    2011-01-01

    T Cha is a nearby (d = 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huelamo et al. (2011) recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel photometry (70, 160, 250, 350, and 500 micron) of T Cha from the "Dust, Ice, and Gas in Time" (DIGIT) Key Program, which bridges the wavelength ...

  7. Polyetheretherketone (PEEK) intervertebral cage as a cause of chronic systemic allergy: a case report.

    Science.gov (United States)

    Maldonado-Naranjo, Andres L; Healy, Andrew T; Kalfas, Iain H

    2015-07-01

    Polyetheretherketone (PEEK) is an organic polymer thermoplastic with strong mechanical and chemical resistance properties. It has been used in industry to fabricate items for demanding applications such as bearings, piston parts, compressor plate valves, and cable insulation. Since the early 1980s, polyetheretherketone polymers have been increasingly used in orthopedic and spinal surgery applications. Numerous studies and years of clinical experience have confirmed the biocompatibility of this material. The purpose of the study was to report a case of chronic systemic allergy after anterior cervical decompression and fusion (ACDF) and implantation of an intervertebral PEEK cage, with resolution of symptoms after removal of PEEK cage. This study is a case report with clinical evidence for allergy to PEEK. The methods involve clinical findings and review of current literature. After ACDF and implantation of an intervertebral PEEK cage, the patient had developed an angioedema-like picture marked by severe redness, itching, swelling of his tongue, and skin thickening. A skin patch test was positive for PEEK. Removal of the implant resulted in the resolution of his allergy symptoms shortly after surgery. Tissue reactions to PEEK are extremely rare. Herein, we present the first report of a chronic allergic response to interbody PEEK material. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. The value of 18F-fluoride PET/CT in the assessment of screw loosening in patients after intervertebral fusion stabilization

    International Nuclear Information System (INIS)

    Seifen, Tanja; Rodrigues, Margarida; Rettenbacher, Lukas; Holzmannhofer, Johannes; Pirich, Christian; Piotrowski, Wolfgang; Mc Coy, Mark

    2015-01-01

    We evaluated 18 F-fluoride PET/CT for the diagnosis of screw loosening after intervertebral fusion stabilization and compared the results with those from functional radiography. A group of 59 patients with pain in the region of previous intervertebral fusion stabilization and suspicion of implant instability due to screw loosening were investigated with 18 F-fluoride PET/CT and functional radiography, 30.1 ± 3.4 and 29.3 ± 3.2 months, respectively, after surgery. The criterion for loosening was increased focal uptake surrounding the screw entry point and shaft. SUV max and SUV mean were measured in a region of interest (ROI) drawn around each screw (334 screws analysed). The final diagnosis was established by surgical exploration in 27 patients and clinical follow-up after intervertebral fusion stabilization in 32 patients. Of the 59 patients, 20 were proven positive for implant failure due to screw loosening and 39 were confirmed negative. The sensitivity, specificity and accuracy of 18 F-fluoride PET/CT were 75 %, 97.4 % and 89.8 % in the patient-based analysis, and 45.6 %, 100 % and 80 % in the screw-based analysis, respectively. The positive and negative predictive values were 93.8 % and 100 % in the patient-based analysis, and 88.4 and 76 % in the screw-based analysis, respectively. CT signs in PET/CT allowed screw breakage to be detected in three patients. SUV max , SUV mean and SUV max /SUV mean ratios in screw ROIs and respective values in reference regions were all found to be significantly different between screws positive for loosening (58 screws) and screws negative for loosening (276 screws). The ratio between SUV max in screw ROIs and the values in reference regions was the most significant parameter for distinguishing screws positive and screws negative for loosening. 18 F-Fluoride PET/CT imaging is useful for the diagnosis of screw loosening in patients with persistent symptoms after intervertebral fusion stabilization. (orig.)

  9. EMBEDDED PROTOSTELLAR DISKS AROUND (SUB-)SOLAR STARS. II. DISK MASSES, SIZES, DENSITIES, TEMPERATURES, AND THE PLANET FORMATION PERSPECTIVE

    International Nuclear Information System (INIS)

    Vorobyov, Eduard I.

    2011-01-01

    We present basic properties of protostellar disks in the embedded phase of star formation (EPSF), which is difficult to probe observationally using available observational facilities. We use numerical hydrodynamics simulations of cloud core collapse and focus on disks formed around stars in the 0.03-1.0 M sun mass range. Our obtained disk masses scale near-linearly with the stellar mass. The mean and median disk masses in the Class 0 and I phases (M mean d,C0 = 0.12 M sun , M mdn d,C0 = 0.09 M sun and M mean d,CI = 0.18 M sun , M mdn d,CI = 0.15 M sun , respectively) are greater than those inferred from observations by (at least) a factor of 2-3. We demonstrate that this disagreement may (in part) be caused by the optically thick inner regions of protostellar disks, which do not contribute to millimeter dust flux. We find that disk masses and surface densities start to systematically exceed that of the minimum mass solar nebular for objects with stellar mass as low as M * = 0.05-0.1 M sun . Concurrently, disk radii start to grow beyond 100 AU, making gravitational fragmentation in the disk outer regions possible. Large disk masses, surface densities, and sizes suggest that giant planets may start forming as early as in the EPSF, either by means of core accretion (inner disk regions) or direct gravitational instability (outer disk regions), thus breaking a longstanding stereotype that the planet formation process begins in the Class II phase.

  10. TOWARD A GLOBAL EVOLUTIONARY MODEL OF PROTOPLANETARY DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xue-Ning, E-mail: xbai@cfa.harvard.edu [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS-51, Cambridge, MA 02138 (United States)

    2016-04-20

    A global picture of the evolution  of protoplanetary disks (PPDs) is key to understanding almost every aspect of planet formation, where standard α-disk models have been continually employed for their simplicity. In the meantime, disk mass loss has been conventionally attributed to photoevaporation, which controls disk dispersal. However, a paradigm shift toward accretion driven by magnetized disk winds has taken place in recent years, thanks to studies of non-ideal magnetohydrodynamic effects in PPDs. I present a framework of global PPD evolution aiming to incorporate these advances, highlighting the role of wind-driven accretion and wind mass loss. Disk evolution is found to be largely dominated by wind-driven processes, and viscous spreading is suppressed. The timescale of disk evolution is controlled primarily by the amount of external magnetic flux threading the disks, and how rapidly the disk loses the flux. Rapid disk dispersal can be achieved if the disk is able to hold most of its magnetic flux during the evolution. In addition, because wind launching requires a sufficient level of ionization at the disk surface (mainly via external far-UV (FUV) radiation), wind kinematics is also affected by the FUV penetration depth and disk geometry. For a typical disk lifetime of a few million years, the disk loses approximately the same amount of mass through the wind as through accretion onto the protostar, and most of the wind mass loss proceeds from the outer disk via a slow wind. Fractional wind mass loss increases with increasing disk lifetime. Significant wind mass loss likely substantially enhances the dust-to-gas mass ratio and promotes planet formation.

  11. TOWARD A GLOBAL EVOLUTIONARY MODEL OF PROTOPLANETARY DISKS

    International Nuclear Information System (INIS)

    Bai, Xue-Ning

    2016-01-01

    A global picture of the evolution  of protoplanetary disks (PPDs) is key to understanding almost every aspect of planet formation, where standard α-disk models have been continually employed for their simplicity. In the meantime, disk mass loss has been conventionally attributed to photoevaporation, which controls disk dispersal. However, a paradigm shift toward accretion driven by magnetized disk winds has taken place in recent years, thanks to studies of non-ideal magnetohydrodynamic effects in PPDs. I present a framework of global PPD evolution aiming to incorporate these advances, highlighting the role of wind-driven accretion and wind mass loss. Disk evolution is found to be largely dominated by wind-driven processes, and viscous spreading is suppressed. The timescale of disk evolution is controlled primarily by the amount of external magnetic flux threading the disks, and how rapidly the disk loses the flux. Rapid disk dispersal can be achieved if the disk is able to hold most of its magnetic flux during the evolution. In addition, because wind launching requires a sufficient level of ionization at the disk surface (mainly via external far-UV (FUV) radiation), wind kinematics is also affected by the FUV penetration depth and disk geometry. For a typical disk lifetime of a few million years, the disk loses approximately the same amount of mass through the wind as through accretion onto the protostar, and most of the wind mass loss proceeds from the outer disk via a slow wind. Fractional wind mass loss increases with increasing disk lifetime. Significant wind mass loss likely substantially enhances the dust-to-gas mass ratio and promotes planet formation

  12. Relativistic, accreting disks

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, M A; Jaroszynski, M; Sikora, M [Polska Akademia Nauk, Warsaw

    1978-02-01

    An analytic theory of the hydrodynamical structure of accreting disks (without self-gravitation but with pressure) orbiting around an axially symmetric, stationary, compact body (e.g. black hole) is presented. The inner edge of the marginally stable accreting disk (i.e. disk with constant angular momentum density) has a sharp cusp located on the equatorial plane between r/sub ms/ and r/sub mb/. The existence of the cusp is also typical for any angular momentum distribution. The physical importance of the cusp follows from the close analogy with the case of a close binary system (L/sub 1/ Lagrange point on the Roche lobe). The existence of the cusp is thus a crucial phenomenon in such problems as boundary condition for the viscous stresses, accretion rate, etc.

  13. IBM 3390 Hard Disk Platter

    CERN Multimedia

    1991-01-01

    The 3390 disks rotated faster than those in the previous model 3380. Faster disk rotation reduced rotational delay (ie. the time required for the correct area of the disk surface to move to the point where data could be read or written). In the 3390's initial models, the average rotational delay was reduced to 7.1 milliseconds from 8.3 milliseconds for the 3380 family.

  14. In vivo intervertebral disc characterization using magnetic resonance spectroscopy and T1ρ imaging: association with discography and Oswestry Disability Index and Short Form-36 Health Survey.

    Science.gov (United States)

    Zuo, Jin; Joseph, Gabby B; Li, Xiaojuan; Link, Thomas M; Hu, Serena S; Berven, Sigurd H; Kurhanewitz, John; Majumdar, Sharmila

    2012-02-01

    An in vivo study of intervertebral disc degeneration by using quantitative magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). To quantify water and proteoglycan (PG) content in the intervertebral disc by using in vivo MRS and to evaluate the relationship between MRS-quantified water/PG content, T1ρ, Pfirrmann score, clinical self-assessment, and discography. Previous in vitro studies have investigated the relationship between MRS-quantified water/PG content and degenerative grade by using cadaveric intervertebral discs. T1ρ has been shown to relate to Pfirrmann grade and clinical self-assessment. However, the associations between MRS-quantified water/PG content, MRI-based T1ρ, self-assessment of health status, and clinical response to discography have not been studied in vivo. MRS and MRI were performed in 26 patients (70 discs) with symptomatic intervertebral degenerative disc (IVDD) and 23 controls (41 discs). Patients underwent evaluation of intervertebral discs with provocative discography. All subjects completed the Short Form-36 Health Survey and Oswestry Disability Index questionnaires. The water/PG peak area ratio was significantly elevated in (a) patients (compared with controls) and in (b) discs with positive discography (compared with negative discography). Magnetic resonance (MR) T1ρ exhibited similar trends. A significant association was found between T1ρ and normalized PG content (R = 0.61, P 0.05). The water/PG peak area ratio, normalized water, normalized PG, and Pfirrmann grade were significantly associated with patient self-assessment of disability and physical composite score, while disc height was not. This study demonstrated a relationship between in vivo MRS spectroscopy (water content and PG content), imaging parameters (T1ρ and Pfirrmann grade), discography results, and clinical self-assessment, suggesting that MRS-quantified water, PG, and MR T1ρ relaxation time may potentially serve as biomarkers of

  15. Formation of Close-in Super-Earths in an Evolving Disk Due to Disk Winds

    Science.gov (United States)

    Ogihara, Masahiro; Kokubo, Eiichiro; Suzuki, Takeru; Morbidelli, Alessandro

    2018-04-01

    Planets with masses larger than Mars mass undergo rapid inward migration (type I migration) in a standard protoplanetary disk. Recent magnetohydrodynamical simulations revealed the presence of magnetically-driven disk winds, which would alter the disk profile and the type I migration in the close-in region (rEarths can be reproduced by simulations. We find that the type I migration is significantly suppressed in a disk with flat surface density profile. After planetary embryos undergo slow inward migration, they are captured in a resonant chain. The resonant chain undergoes late orbital instability during the gas depletion, leading to a non-resonant configuration. We also find that observed distributions of close-in super-Earths (e.g., period ratio, mass ratio) can be reproduced by results of simulations.

  16. MR appearance of neonatal and fetal intervertebral disks

    International Nuclear Information System (INIS)

    Ho, P.S.P.; Yu, S.; Lynch, K.L.; Ho, K.C.; Haughton, V.M.

    1987-01-01

    The infant spine has a different MR appearance than the adult spine. The authors used MR and cryomicrotomy to study the spines of stillborn fetuses and infants during in the perinatal period. In the fetal spine, Sharpey fibers are incompletely developed, the nucleus and anulus are more distinctly differentiated, the nucleus contains a transverse structure not seen in the adult, notochordal cells are more prominent, and the vertebral bodies and neural arches are incompletely ossified. The spinal landmarks and their MR appearances will be illustrated. Variations, such as calcification of the nucleus pulposus, are illustrated

  17. Cartilage of the Intervertebral Disc Eng-Plate, A Histological, Histochemical, Fine Structure Study.

    Science.gov (United States)

    1982-08-01

    degeneration (Nachemson et al., 1970). These and related studies consider the end-plates to be composed of hyaline cartilage and thus homologues of articular...results of this study in rhesus indicate, that while present, the cartilage of the end-plate is quite different in structure and presumably...HZSTOLO6ZCAL,-ETCfU) I AUG 82 N 5 NUSSBAUM IUNCLASSIFDATRL8R-1222NL.rnximommmB~iIEND2 AFAMRL-TR-81 - 122 " CARTILAGE OF THE INTERVERTEBRAL DISC END-PLATE A

  18. Hydrogen Cyanide In Protoplanetary Disks

    Science.gov (United States)

    Walker, Ashley L.; Oberg, Karin; Cleeves, L. Ilsedore

    2018-01-01

    The chemistry behind star and planet formation is extremely complex and important in the formation of habitable planets. Life requires molecules containing carbon, oxygen, and importantly, nitrogen. Hydrogen cyanide, or HCN, one of the main interstellar nitrogen carriers, is extremely dangerous here on Earth. However, it could be used as a vital tool for tracking the chemistry of potentially habitable planets. As we get closer to identifying other habitable planets, we must understand the beginnings of how those planets are formed in the early protoplanetary disk. This project investigates HCN chemistry in different locations in the disk, and what this might mean for forming planets at different distances from the star. HCN is a chemically diverse molecule. It is connected to the formation for other more complex molecules and is commonly used as a nitrogen tracer. Using computational chemical models we look at how the HCN abundance changes at different locations. We use realistic and physically motivated conditions for the gas in the protoplanetary disk: temperature, density, and radiation (UV flux). We analyze the reaction network, formation, and destruction of HCN molecules in the disk environment. The disk environment informs us about stability of habitable planets that are created based on HCN molecules. We reviewed and compared the difference in the molecules with a variety of locations in the disk and ultimately giving us a better understanding on how we view protoplanetary disks.

  19. CO Gas Inside the Protoplanetary Disk Cavity in HD 142527: Disk Structure from ALMA

    OpenAIRE

    Perez, S.; Casassus, S.; Ménard, F.; Roman, P.; van der Plas, G.; Cieza, L.; Pinte, C.; Christiaens, Valentin; Hales, A. S.

    2014-01-01

    Inner cavities and annular gaps in circumstellar disks are possible signposts of giant planet formation. The young star HD 142527 hosts a massive protoplanetary disk with a large cavity that extends up to 140 AU from the central star, as seen in continuum images at infrared and millimeter wavelengths. Estimates of the survival of gas inside disk cavities are needed to discriminate between clearing scenarios. We present a spatially and spectrally resolved carbon monoxide isotopologue 2-1 line ...

  20. The Tilt between Acretion Disk and Stellar Disk Shiyin Shen1,2 ...

    Indian Academy of Sciences (India)

    80 Nandan Road, Shanghai 200030, China. 2Key Lab for Astrophysics, Shanghai 200234, China. ∗ e-mail: ssy@shao.ac.cn. Abstract. The orientations .... shows the model prediction from the stellar dust model (section 5). 4. Result: The tilt between the accretion disk and stellar disk. We parameterize the inclinations of the ...

  1. Cold disks : Spitzer spectroscopy of disks around young stars with large gaps

    NARCIS (Netherlands)

    Blake, G. A.; Dullemond, C. P.; Merin, B.; Augereau, J. C.; Boogert, A. C. A.; Evans, N. J.; Geers, V. C.; Lahuis, F.; Kessler-Silacci, J. E.; Pontoppidan, K. M.; van Dishoeck, E. F.; Brown, J.M.

    2007-01-01

    We have identified four circumstellar disks with a deficit of dust emission from their inner 15-50 AU. All four stars have F-G spectral type and were uncovered as part of the Spitzer Space Telescope "Cores to Disks" Legacy Program Infrared Spectrograph (IRS) first-look survey of similar to 100 pre -

  2. Covering and piercing disks with two centers

    KAUST Repository

    Ahn, Heekap; Kim, Sangsub; Knauer, Christian; Schlipf, Lena; Shin, Chansu; Vigneron, Antoine E.

    2011-01-01

    We consider new versions of the two-center problem where the input consists of a set D of disks in the plane. We first study the problem of finding two smallest congruent disks such that each disk in intersects one of these two disks. Then we study the problem of covering the set D by two smallest congruent disks. We give exact and approximation algorithms for these versions. © 2011 Springer-Verlag.

  3. Verbatim Floppy Disk

    CERN Multimedia

    1976-01-01

    Introduced under the name "Verbatim", Latin for "literally", these disks that sized more than 5¼ inches have become almost universal on dedicated word processing systems and personal computers. This format was replaced more slowly by the 3½-inch format, introduced for the first time in 1982. Compared to today, these large format disks stored very little data. In reality, they could only contain a few pages of text.

  4. Safety of intradiscal injection and biocompatibility of polyester amide microspheres in a canine model predisposed to intervertebral disc degeneration

    NARCIS (Netherlands)

    Willems, Nicole; Mihov, George; Grinwis, Guy C M; van Dijk, Maarten; Schumann, Detlef; Bos, Clemens; Strijkers, Gustav J; Dhert, Wouter J A; Meij, Björn P; Creemers, Laura B.; Tryfonidou, Marianna A

    Repair of degenerated intervertebral discs (IVD) might be established via intradiscal delivery of biologic therapies. Polyester amide polymers (PEA) were evaluated for in vitro cytotoxicity and in vivo biocompatibility, and thereafter intradiscal application of PEA microspheres (PEAMs) in a canine

  5. Safety of intradiscal injection and biocompatibility of polyester amide microspheres in a canine model predisposed to intervertebral disc degeneration

    NARCIS (Netherlands)

    Willems, Nicole; Mihov, George; Grinwis, Guy C. M.; van Dijk, Maarten; Schumann, Detlef; Bos, Clemens; Strijkers, Gustav J.; Dhert, Wouter J. A.; Meij, Björn P.; Creemers, Laura B.; Tryfonidou, Marianna A.

    2017-01-01

    Repair of degenerated intervertebral discs (IVD) might be established via intradiscal delivery of biologic therapies. Polyester amide polymers (PEA) were evaluated for in vitro cytotoxicity and in vivo biocompatibility, and thereafter intradiscal application of PEA microspheres (PEAMs) in a canine

  6. Astrophysical disks Collective and Stochastic Phenomena

    CERN Document Server

    Fridman, Alexei M; Kovalenko, Ilya G

    2006-01-01

    The book deals with collective and stochastic processes in astrophysical discs involving theory, observations, and the results of modelling. Among others, it examines the spiral-vortex structure in galactic and accretion disks , stochastic and ordered structures in the developed turbulence. It also describes sources of turbulence in the accretion disks, internal structure of disk in the vicinity of a black hole, numerical modelling of Be envelopes in binaries, gaseous disks in spiral galaxies with shock waves formation, observation of accretion disks in a binary system and mass distribution of luminous matter in disk galaxies. The editors adaptly brought together collective and stochastic phenomena in the modern field of astrophysical discs, their formation, structure, and evolution involving the methodology to deal with, the results of observation and modelling, thereby advancing the study in this important branch of astrophysics and benefiting Professional Researchers, Lecturers, and Graduate Students.

  7. Gravitational Instabilities in Circumstellar Disks

    Science.gov (United States)

    Kratter, Kaitlin; Lodato, Giuseppe

    2016-09-01

    Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review, we focus on the role of gravitational instability in this process. We begin with a brief overview of the observational evidence for massive disks that might be subject to gravitational instability and then highlight the diverse ways in which the instability manifests itself in protostellar and protoplanetary disks: the generation of spiral arms, small-scale turbulence-like density fluctuations, and fragmentation of the disk itself. We present the analytic theory that describes the linear growth phase of the instability supplemented with a survey of numerical simulations that aim to capture the nonlinear evolution. We emphasize the role of thermodynamics and large-scale infall in controlling the outcome of the instability. Despite apparent controversies in the literature, we show a remarkable level of agreement between analytic predictions and numerical results. In the next part of our review, we focus on the astrophysical consequences of the instability. We show that the disks most likely to be gravitationally unstable are young and relatively massive compared with their host star, Md/M*≥0.1. They will develop quasi-stable spiral arms that process infall from the background cloud. Although instability is less likely at later times, once infall becomes less important, the manifestations of the instability are more varied. In this regime, the disk thermodynamics, often regulated by stellar irradiation, dictates the development and evolution of the instability. In some cases the instability may lead to fragmentation into bound companions. These companions are more likely to be brown dwarfs or stars than planetary mass objects. Finally, we highlight open questions related to the development of a turbulent cascade in thin disks and the role of mode-mode coupling in setting the maximum angular

  8. Development of Powered Disk Type Sugar Cane Stubble Saver

    Directory of Open Access Journals (Sweden)

    Radite P.A.S.

    2009-04-01

    Full Text Available The objective of this research was to design, fabricate and test a prototype of sugar cane stubble saver based on powered disk mechanism. In this research, a heavy duty disk plow or disk harrow was used as a rotating knife to cut the sugarcane stubble. The parabolic disk was chosen because it is proven reliable as soil working tools and it is available in the market as spare part of disk plow or disk harrow unit. The prototype was mounted on the four wheel tractor’s three point hitch, and powered by PTO of the tractor. Two kinds of disks were used in these experiments, those were disk with regular edge or plain disk and disk with scalloped edge or scalloped disk. Both disks had diameter of 28 inch. Results of field test showed that powered disk mechanism could satisfy cut sugar cane’s stubble. However, scalloped disk type gave smoother stubble cuts compared to that of plain disk. Plain disk type gave broken stubble cut. Higher rotation (1000 rpm resulted better cuts as compared to lower rotation (500 rpm both either on plain disk and scalloped disk. The developed prototype could work below the soil surface at depth of 5 to 10 cm. With tilt angle setting 20O and disk angle 45O the width of cut was about 25 cm.

  9. Inter-examiner reliability of passive assessment of intervertebral motion in the cervical and lumbar spine: A systematic review

    NARCIS (Netherlands)

    van Trijffel, E.; Anderegg, Q.; Bossuyt, P. M. M.; Lucas, C.

    2005-01-01

    A systematic review was conducted to determine inter-examiner reliability of passive assessment of segmental intervertebral motion in the cervical and lumbar spine as well as to explore sources of heterogeneity. Passive assessment of motion is used to decide on treatments for neck and low-back pain

  10. Accretion in Radiative Equipartition (AiRE) Disks

    Energy Technology Data Exchange (ETDEWEB)

    Yazdi, Yasaman K.; Afshordi, Niayesh, E-mail: yyazdi@pitp.ca, E-mail: nafshordi@pitp.ca [Perimeter Institute for Theoretical Physics, 31 Caroline Street N, Waterloo, ON N2L 2Y5 (Canada)

    2017-07-01

    Standard accretion disk theory predicts that the total pressure in disks at typical (sub-)Eddington accretion rates becomes radiation pressure dominated. However, radiation pressure dominated disks are thermally unstable. Since these disks are observed in approximate steady state over the instability timescale, our accretion models in the radiation-pressure-dominated regime (i.e., inner disk) need to be modified. Here, we present a modification to the Shakura and Sunyaev model, where the radiation pressure is in equipartition with the gas pressure in the inner region. We call these flows accretion in radiative equipartition (AiRE) disks. We introduce the basic features of AiRE disks and show how they modify disk properties such as the Toomre parameter and the central temperature. We then show that the accretion rate of AiRE disks is limited from above and below, by Toomre and nodal sonic point instabilities, respectively. The former leads to a strict upper limit on the mass of supermassive black holes as a function of cosmic time (and spin), while the latter could explain the transition between hard and soft states of X-ray binaries.

  11. Modeling Protoplanetary Disks

    Science.gov (United States)

    Holman, Megan; Tubbs, Drake; Keller, L. D.

    2018-01-01

    Using spectra models with known parameters and comparing them to spectra gathered from real systems is often the only ways to find out what is going on in those real systems. This project uses the modeling programs of RADMC-3D to generate model spectra for systems containing protoplanetary disks. The parameters can be changed to simulate protoplanetary disks in different stages of planet formation, with different sized gaps in different areas of the disks, as well as protoplanetary disks that contain different types of dust. We are working on producing a grid of models that all have different variations in the parameters in order to generate a miniature database to use for comparisons to gathered spectra. The spectra produced from these simulations will be compared to spectra that have been gathered from systems in the Small Magellanic cloud in order to find out the contents and stage of development of that system. This allows us to see if and how planets are forming in the Small Magellanic cloud, a region which has much less metallicity than our own galaxy. The data we gather from comparisons between the model spectra and the spectra of systems in the Small Magellanic Cloud can then be applied to how planets may have formed in the early universe.

  12. The Fabulous Four Debris Disks

    Science.gov (United States)

    Werner, Michael; Stapelfeldt, Karl

    2004-09-01

    This program is a comprehensive study of the four bright debris disks that were spatially resolved by IRAS: Beta Pictoris, Epsilon Eridani, Fomalhaut, and Vega. All SIRTF instruments and observing modes will be used. The program has three major objectives: (1) Study of the disk spatial structure from MIPS and IRAC imaging; (2) Study of the dust grain composition using the IRS and MIPS SED mode; and (3) companion searches using IRAC. The data from this program should lead to a detailed understanding of these four systems, and will provide a foundation for understanding all of the debris disks to be studied with SIRTF. Images and spectra will be compared with models for disk structure and dust properties. Dynamical features indicative of substellar companions' effects on the disks will be searched for. This program will require supporting observations of PSF stars, some of which have been included explicitly. In the majority of cases, the spectral observations require a preferred orientation to align the slits along the disk position angles. Detector saturation issues are still being worked for this program, and will lead to AOR modifications in subsequent submissions. The results from this program will be analyzed collaboratively by the IRAC, IRS, and MIPS teams and by general GTOs Jura and Werner.

  13. Complaints of the lumbar spine: The value of myelography and computerized tomography

    International Nuclear Information System (INIS)

    Rittmeyer, K.; Dralle, A.

    1988-01-01

    In the radiological examination of the lumbar spine and vertebral canal there are currently two methods of choice, computer tomography and myelography. Comparing the advantages of one method over another reveals that computer tomography is particularly useful in especially diagnosing a lateral process of the intervertebral disk, whereas myelography is especially applicable in the case of an intervertebrals disk prolapse within the narrow confines of the spinal canal proper. Myelography also has the additional advantage of visualizing a number of segments at once, although repeated use increases the risk of arachnitis despite the high tolerance of current contrast medium. However, myelography should be performed, if there is clinical evidence of nerve root compression even though the computer tomography was negative. The reverse is also true. Myelography is also useful initially, due to the lower radiation dosis, if the clinical symptoms don't allow a specific localisation of the process. (orig.) [de

  14. Nuclear magnetic resonance tomography of the cervical canal

    Energy Technology Data Exchange (ETDEWEB)

    Terwey, B.; Koschorek, F.; Jensen, H.P.

    1985-12-01

    170 patients with suspected lesions of the cervical part of the medulla were examined using nuclear magnetic resonance (NMR) tomography. 27 cases revealed no pathological changes in the regions of the cervical medulla, the cervical canal and of the cervical spine. 143 cases produced pathological findings whose diagnoses determined therapeutical approach. Verified pathological changes comprised anomalies of the cranio-cervical junction like basilar impression and Arnold-Chiari malformation, various types of cavity formation in the cervical medulla (syringomyelia, hydromyelia), demyelinization processes, intramedullary and extramedullary tumours, intervertebral disk degeneration processes, dislocation of intervertebral disks and spondylophytes with spinal stenoses. Sagittal sections in different functional positions allowed to demonstrate the biomechanical effects of extramedullary masses on the cervical medulla. However, proven tumours could not be differentiated successfully using histological methods. Nevertheless, NMR tomography will replace invasive methods like conventional cervical myelography and CT myelography in diagnostic clarification of diseases of the cervical medulla.

  15. THE VLA VIEW OF THE HL TAU DISK: DISK MASS, GRAIN EVOLUTION, AND EARLY PLANET FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco-González, Carlos; Rodríguez, Luis F.; Galván-Madrid, Roberto [Instituto de Radioastronomía y Astrofísica UNAM, Apartado Postal 3-72 (Xangari), 58089 Morelia, Michoacán, México (Mexico); Henning, Thomas; Linz, Hendrik; Birnstiel, Til; Boekel, Roy van; Klahr, Hubert [Max-Planck-Institut für Astronomie Heidelberg, Königstuhl 17, D-69117 Heidelberg (Germany); Chandler, Claire J.; Pérez, Laura [National Radio Astronomy Observatory, P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801-0387 (United States); Anglada, Guillem; Macias, Enrique; Osorio, Mayra [Instituto de Astrofísica de Andalucía (CSIC), Apartado 3004, E-18080 Granada (Spain); Flock, Mario [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Menten, Karl [Jansky Fellow of the National Radio Astronomy Observatory (United States); Testi, Leonardo [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München (Germany); Torrelles, José M. [Institut de Ciències de l’Espai (CSIC-IEEC) and Institut de Ciències del Cosmos (UB-IEEC), Martí i Franquès 1, E-08028 Barcelona (Spain); Zhu, Zhaohuan, E-mail: c.carrasco@crya.unam.mx, E-mail: l.rodriguez@crya.unam.mx, E-mail: r.galvan@crya.unam.mx, E-mail: henning@mpia.de, E-mail: linz@mpia.de [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2016-04-10

    The first long-baseline ALMA campaign resolved the disk around the young star HL Tau into a number of axisymmetric bright and dark rings. Despite the very young age of HL Tau, these structures have been interpreted as signatures for the presence of (proto)planets. The ALMA images triggered numerous theoretical studies based on disk–planet interactions, magnetically driven disk structures, and grain evolution. Of special interest are the inner parts of disks, where terrestrial planets are expected to form. However, the emission from these regions in HL Tau turned out to be optically thick at all ALMA wavelengths, preventing the derivation of surface density profiles and grain-size distributions. Here, we present the most sensitive images of HL Tau obtained to date with the Karl G. Jansky Very Large Array at 7.0 mm wavelength with a spatial resolution comparable to the ALMA images. At this long wavelength, the dust emission from HL Tau is optically thin, allowing a comprehensive study of the inner disk. We obtain a total disk dust mass of (1–3) × 10{sup −3} M {sub ⊙}, depending on the assumed opacity and disk temperature. Our optically thin data also indicate fast grain growth, fragmentation, and formation of dense clumps in the inner densest parts of the disk. Our results suggest that the HL Tau disk may be actually in a very early stage of planetary formation, with planets not already formed in the gaps but in the process of future formation in the bright rings.

  16. THE VLA VIEW OF THE HL TAU DISK: DISK MASS, GRAIN EVOLUTION, AND EARLY PLANET FORMATION

    International Nuclear Information System (INIS)

    Carrasco-González, Carlos; Rodríguez, Luis F.; Galván-Madrid, Roberto; Henning, Thomas; Linz, Hendrik; Birnstiel, Til; Boekel, Roy van; Klahr, Hubert; Chandler, Claire J.; Pérez, Laura; Anglada, Guillem; Macias, Enrique; Osorio, Mayra; Flock, Mario; Menten, Karl; Testi, Leonardo; Torrelles, José M.; Zhu, Zhaohuan

    2016-01-01

    The first long-baseline ALMA campaign resolved the disk around the young star HL Tau into a number of axisymmetric bright and dark rings. Despite the very young age of HL Tau, these structures have been interpreted as signatures for the presence of (proto)planets. The ALMA images triggered numerous theoretical studies based on disk–planet interactions, magnetically driven disk structures, and grain evolution. Of special interest are the inner parts of disks, where terrestrial planets are expected to form. However, the emission from these regions in HL Tau turned out to be optically thick at all ALMA wavelengths, preventing the derivation of surface density profiles and grain-size distributions. Here, we present the most sensitive images of HL Tau obtained to date with the Karl G. Jansky Very Large Array at 7.0 mm wavelength with a spatial resolution comparable to the ALMA images. At this long wavelength, the dust emission from HL Tau is optically thin, allowing a comprehensive study of the inner disk. We obtain a total disk dust mass of (1–3) × 10 −3 M ⊙ , depending on the assumed opacity and disk temperature. Our optically thin data also indicate fast grain growth, fragmentation, and formation of dense clumps in the inner densest parts of the disk. Our results suggest that the HL Tau disk may be actually in a very early stage of planetary formation, with planets not already formed in the gaps but in the process of future formation in the bright rings

  17. CONSTRAINTS ON COMPTON-THICK WINDS FROM BLACK HOLE ACCRETION DISKS: CAN WE SEE THE INNER DISK?

    International Nuclear Information System (INIS)

    Reynolds, Christopher S.

    2012-01-01

    Strong evidence is emerging that winds can be driven from the central regions of accretion disks in both active galactic nuclei and Galactic black hole binaries. Direct evidence for highly ionized, Compton-thin inner-disk winds comes from observations of blueshifted (v ∼ 0.05-0.1c) iron-K X-ray absorption lines. However, it has been suggested that the inner regions of black hole accretion disks can also drive Compton-thick winds—such winds would enshroud the inner disk, preventing us from seeing direct signatures of the accretion disk (i.e., the photospheric thermal emission, or the Doppler/gravitationally broadened iron Kα line). Here, we show that, provided the source is sub-Eddington, the well-established wind-driving mechanisms fail to launch a Compton-thick wind from the inner disk. For the accelerated region of the wind to be Compton-thick, the momentum carried in the wind must exceed the available photon momentum by a factor of at least 2/λ, where λ is the Eddington ratio of the source, ruling out radiative acceleration unless the source is very close to the Eddington limit. Compton-thick winds also carry large mass fluxes, and a consideration of the connections between the wind and the disk shows this to be incompatible with magneto-centrifugal driving. Finally, thermal driving of the wind is ruled out on the basis of the large Compton radii that typify black hole systems. In the absence of some new acceleration mechanisms, we conclude that the inner regions of sub-Eddington accretion disks around black holes are indeed naked.

  18. PLANETESIMAL AND PROTOPLANET DYNAMICS IN A TURBULENT PROTOPLANETARY DISK: IDEAL UNSTRATIFIED DISKS

    International Nuclear Information System (INIS)

    Yang, Chao-Chin; Mac Low, Mordecai-Mark; Menou, Kristen

    2009-01-01

    The dynamics of planetesimals and planetary cores may be strongly influenced by density perturbations driven by magneto-rotational turbulence in their natal protoplanetary gas disks. Using the local shearing box approximation, we perform numerical simulations of planetesimals moving as massless particles in a turbulent, magnetized, unstratified gas disk. Our fiducial disk model shows turbulent accretion characterized by a Shakura-Sunyaev viscosity parameter of α ∼ 10 -2 , with rms density perturbations of ∼10%. We measure the statistical evolution of particle orbital properties in our simulations including mean radius, eccentricity, and velocity dispersion. We confirm random walk growth in time of all three properties, the first time that this has been done with direct orbital integration in a local model. We find that the growth rate increases with the box size used at least up to boxes of eight scale heights in horizontal size. However, even our largest boxes show velocity dispersions sufficiently low that collisional destruction of planetesimals should be unimportant in the inner disk throughout its lifetime. Our direct integrations agree with earlier torque measurements showing that type I migration dominates over diffusive migration by stochastic torques for most objects in the planetary core and terrestrial planet mass range. Diffusive migration remains important for objects in the mass range of kilometer-sized planetesimals. Discrepancies in the derived magnitude of turbulence between local and global simulations of magneto-rotationally unstable disks remains an open issue, with important consequences for planet formation scenarios.

  19. Circumstellar Gas in Young Planetary Debris Disks

    Science.gov (United States)

    Roberge, A.

    Circumstellar (CS) disks orbiting young stars fall into two categories: primordial disks, composed of unprocessed interstellar dust and gas, and debris disks, produced by the destruction of solid planetary bodies. In the first class, the most abundant gas is H_2; in the second, it appears that the H_2 gas has disappeared, possibly through incorporation into gas giant planets. The lifetime of H_2 gas in a CS disk is therefore of great importance, as it dictates the timescale for the formation of giant planets. FUSE observations of H_2 in CS disk systems have shown that FUV absorption spectroscopy may sensitively probe for small amounts of gas along the line of sight to the star. Most importantly, the FUSE non-detection of H_2 gas in the Beta Pictoris disk suggests that the primordial gas lifetime is less than about 12 Myr, and that gas giant planets must form very quickly. However, this suggestion is based on one system, and needs to be tested in additional systems with a range of ages, especially since there are indications that age is not the only factor in the evolution of a CS disk. We propose for FUSE observations of 3 additional debris disk systems, Fomalhaut, HD3003, and HD2884. Fomalhaut is an intermediate age debris disk, one of the Fabulous Four CS disks first discovered in 1984. The other two disks are younger, with ages similar to that of Beta Pic. All three stars are brighter in the FUV than Beta Pic, permitting us to sensitively probe for traces of H_2 gas. We will also measure the amount of secondary atomic gas produced from planetary bodies in these disks, in an effort to understand the entire evolution of CS gas in young planetary systems.

  20. A New M Dwarf Debris Disk Candidate in a Young Moving Group Discovered with Disk Detective

    Science.gov (United States)

    Silverberg, Steven M.; Kuchner, Marc J.; Wisniewski, John P.; Gagne, Jonathan; Bans, Alissa S.; Bhattacharjee, Shambo; Currie, Thayne R.; Debes, John R.; Biggs, Joseph R; Bosch, Milton

    2016-01-01

    We used the Disk Detective citizen science project and the BANYAN II Bayesian analysis tool to identify a new candidate member of a nearby young association with infrared excess. WISE J080822.18-644357.3, an M5.5-type debris disk system with significant excess at both 12 and 22 microns, is a likely member (approx.90% BANYAN II probability) of the approx.45 Myr old Carina association. Since this would be the oldest M dwarf debris disk detected in a moving group, this discovery could be an important constraint on our understanding of M dwarf debris disk evolution.

  1. Sodium-23 MRI of whole spine at 3 Tesla using a 5-channel receive-only phased-array and a whole-body transmit resonator

    Energy Technology Data Exchange (ETDEWEB)

    Malzacher, Matthias; Kalayciyan, Raffi; Konstandin, Simon; Schad, Lothar R. [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Haneder, Stefan [Heidelberg Univ., Mannheim (Germany). Clinical Radiology and Nuclear Medicine; University Hospital of Cologne, Koeln (Germany). Dept. of Radiology

    2016-05-01

    Sodium magnetic resonance imaging ({sup 23}Na MRI) is a unique and non-invasive imaging technique which provides important information on cellular level about the tissue of the human body. Several applications for {sup 23}Na MRI were investigated with regard to the examination of the tissue viability and functionality for example in the brain, the heart or the breast. The {sup 23}Na MRI technique can also be integrated as a potential monitoring instrument after radiotherapy or chemotherapy. The main contribution in this work was the adaptation of {sup 23}Na MRI for spine imaging, which can provide essential information on the integrity of the intervertebral disks with respect to the early detection of disk degeneration. In this work, a transmit-only receive-only dual resonator system was designed and developed to cover the whole human spine using {sup 23}Na MRI and increase the receive sensitivity. The resonator system consisted of an already presented {sup 23}Na whole-body resonator and a newly developed 5-channel receive-only phased-array. The resonator system was first validated using bench top and phantom measurements. A threefold SNR improvement at the depth of the spine (∝7 cm) over the whole-body resonator was achieved using the spine array. {sup 23}Na MR measurements of the human spine using the transmit-only receive-only resonator system were performed on a healthy volunteer within an acquisition time of 10 minutes. A density adapted 3D radial sequence was chosen with 6 mm isotropic resolution, 49 ms repetition time and a short echo time of 540 μs. Furthermore, it was possible to quantify the tissue sodium concentration in the intervertebral discs in the lumbar region (120 ms repetition time) using this setup.

  2. Diagnostic significance of CT discography

    International Nuclear Information System (INIS)

    Nishiyama, Toru; Tomita, Yu; Maeda, Katsuhisa; Takayama, Atsuya; Takada, Shunichi; Murakami, Masazumi; Saito, Yasufumi.

    1986-01-01

    In a total of 179 patients, comprising 161 with intervertebral disorder and 18 with spondylolysis or spondylolisthesis, CT discographic findings of 456 intervertebral discs were reviewed. Computed tomographic discography showed the direction of herniation, the size of hernial masses, and the deformity of the intervertebral disc and joint, being helpful in deciding indications for surgery and selecting surgical procedures. Computed tomographic discographic patterns of disk deformity were classified as types A, B, and C. This classification almost concurred with the findings of conventional discography. Discography or CT discography is recommended to be used when deformity at the L5-S1 level may be missed on myelography and there is extraforaminal lateral disc herniation. Combined use of myelography, discography, and CT discography would increase the diagnostic accuracy for lumbar diseases. (Namekawa, K.)

  3. Circumstellar disks around binary stars in Taurus

    International Nuclear Information System (INIS)

    Akeson, R. L.; Jensen, E. L. N.

    2014-01-01

    We have conducted a survey of 17 wide (>100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems as an aid to understanding the role of multiplicity in star and planet formation. The ALMA observations had sufficient resolution to localize emission within the binary system. Disk emission was detected around all primaries and 10 secondaries, with disk masses as low as 10 –4 M ☉ . We compare the properties of our sample to the population of known disks in Taurus and find that the disks from this binary sample match the scaling between stellar mass and millimeter flux of F mm ∝M ∗ 1.5--2.0 to within the scatter found in previous studies. We also compare the properties of the primaries to those of the secondaries and find that the secondary/primary stellar and disk mass ratios are not correlated; in three systems, the circumsecondary disk is more massive than the circumprimary disk, counter to some theoretical predictions.

  4. Application of a semiautomatic classifier for modic and disk hernia changes in magnetic resonance

    Directory of Open Access Journals (Sweden)

    Eduardo López Arce Vivas

    2015-03-01

    Full Text Available OBJECTIVE: Early detection of degenerative changes in lumbar intervertebral disc by magnetic resonance imaging in a semiautomatic classifier for prevention of degenerative disease. METHOD: MRIs were selected with a diagnosis of degenerative disc disease or back pain from January to May 2014, with a sample of 23 patients and a total of 170 disks evaluated by sagittal T2 MRI image, first evaluated by a specialist physician in training and them were introduced into the software, being the results compared. RESULTS: One hundred and fifteen discs were evaluated by a programmed semiautomatic classifier to identify MODIC changes and hernia, which produced results "normal or MODIC" and "normal or abnormal", respectively. With a total of 230 readings, of which 141 were correct, 84 were reading errors and 10 readings were undiagnosed, the semiautomatic classifier is a useful tool for early diagnosis or established disease and is easy to apply because of the speed and ease of use; however, at this early stage of development, software is inferior to clinical observations and the results were from around 65% to 60% certainty for MODIC rating and 61% to 58% for disc herniation, compared with clinical evaluations. CONCLUSION: The comparative results between the two doctors were 94 consistent results and only 21 errors, which represents 81% certainty.

  5. Thoracic mobilisation and periscapular soft tissue manipulations in the management of chronic Prolapsed Intervertebral Disc (PIVD - An innovative manual therapy approach

    Directory of Open Access Journals (Sweden)

    Raj Kiran

    2017-10-01

    Full Text Available Background The most common cause of CLBP is discogenic lower back pain. Researches haveshown that connective tissue remodelling occurs in CLBP and thoracic spinal mobility and thoracolumbar mobility have higher correlations with LBP. Aims To see the effect of upper back fascia and periscapular muscles stretching and thoracic mobilisation to reduce symptoms in subjects with CLBP due to lumbar disk herniation. Methods A total of 40 subjects with CLBP due to Prolapsed Intervertebral Disc (PIVD were recruited and randomly distributed in two groups. Group 1 was given stretching of upper back fascia and periscapular muscles and thoracic mobilization along with conventional exercises (Cyriax listing correction -I followed by repeated McKenzie back extension exercise and Core muscle strengthening. Group 2 received only conventional exercises. Outcome Measures: visual analog scale, Oswestry Disability Index and Modified Schober's Test. Measurements were taken before and after three weeks of treatment, for five days/week. Results Overall results of the study, both Group 1 and Group 2 showed improvement in pain, function and lumbar Range of Motion (ROM after three weeks of intervention. However, Group 1 improved significantly to a greater extent in pain, ROM and function than the Group 2. Conclusion Stretching of periscapular muscles and fascia of the upper back and mobilisation of upper thoracic spine is found to be effective for the management of chronic low back pain due to PIVD.

  6. The Relationship amongst Intervertebral Disc Vertical Diameter, Lateral Foramen Diameter and Nerve Root Impingement in Lumbar Vertebra

    Directory of Open Access Journals (Sweden)

    Yusof MI

    2018-03-01

    Full Text Available Introduction: The vertical diameter of the foramen is dependent upon the vertical diameter of the corresponding intervertebral disc. A decrease in disc vertical diameter has direct anatomic consequences to the foraminal diameter and area available for the nerve root passing through it. This study is to establish the relationship amongst the intervertebral disc vertical diameter, lateral foramen diameters and nerve root compression in the lumbar vertebra. Materials and Methods: Measurements of the study parameters were performed using sagittal MRI images. The parameters studied were: intervertebral disc vertical diameter (DVD, foraminal vertical diameter (FVD, foraminal transverse diameter (FTD and nerve root diameter (NRD of both sides. The relationship between the measured parameters were then analyzed. Results: A total of 62 MRI images were available for this study. Statistical analysis showed moderate to strong correlation between DVD and FVD at all the lumbar levels except at left L23 and L5S1 and right L3L4 and L4L5. Correlation between DVD and FTD were not significant at all lumbar levels. Regression analysis showed that a decrease of 1mm of DVD was associated with 1.3, 1.7, 3.3, 3.3 and 1.3mm reduction of FVD at L1L2, L2L3, L3L4, L4L5 and L5S1 respectively. Conclusion: Reduction of DVD was associated with reduction of FVD. However, FVD was relatively wide for the nerve root even with complete loss of DVD. FTD was much narrower than the FVD making it more likely to cause nerve root compression at the exit foramina. These anatomical details should be given consideration in treating patients with lateral canal stenosis.

  7. İntervertebral disk patofizyolojisinde rol oynayan etmenler

    OpenAIRE

    Aktar Reyhanioğlu, Duygu

    2014-01-01

    Intervertebral disc locating between two vertebrae and maintaining support function and structures that remain vertebraes together. İt is the most important part of functional movement system and consisting of anulus fibrosus , nucleus pulposus, and vertebral endplate. İntervertebral disc degeneration is the loss of functionality of disc as a result of physiologic, chemical and mechanic pathology. As a result of functional unit damage occuring loss of function, spread all spinal column.In thi...

  8. MIGRATION TRAPS IN DISKS AROUND SUPERMASSIVE BLACK HOLES

    International Nuclear Information System (INIS)

    Bellovary, Jillian M.; Low, Mordecai-Mark Mac; McKernan, Barry; Ford, K. E. Saavik

    2016-01-01

    Accretion disks around supermassive black holes (SMBHs) in active galactic nuclei (AGNs) contain stars, stellar mass black holes, and other stellar remnants, which perturb the disk gas gravitationally. The resulting density perturbations exert torques on the embedded masses causing them to migrate through the disk in a manner analogous to planets in protoplanetary disks. We determine the strength and direction of these torques using an empirical analytic description dependent on local disk gradients, applied to two different analytic, steady-state disk models of SMBH accretion disks. We find that there are radii in such disks where the gas torque changes sign, trapping migrating objects. Our analysis shows that major migration traps generally occur where the disk surface density gradient changes sign from positive to negative, around 20–300R g , where R g  = 2GM/c 2 is the Schwarzschild radius. At these traps, massive objects in the AGN disk can accumulate, collide, scatter, and accrete. Intermediate mass black hole formation is likely in these disk locations, which may lead to preferential gap and cavity creation at these radii. Our model thus has significant implications for SMBH growth as well as gravitational wave source populations

  9. A developmental transcriptomic analysis of Pax1 and Pax9 in embryonic intervertebral disc development

    Directory of Open Access Journals (Sweden)

    V. Sivakamasundari

    2017-02-01

    Full Text Available Pax1 and Pax9 play redundant, synergistic functions in the patterning and differentiation of the sclerotomal cells that give rise to the vertebral bodies and intervertebral discs (IVD of the axial skeleton. They are conserved in mice and humans, whereby mutation/deficiency of human PAX1/PAX9 has been associated with kyphoscoliosis. By combining cell-type-specific transcriptome and ChIP-sequencing data, we identified the roles of Pax1/Pax9 in cell proliferation, cartilage development and collagen fibrillogenesis, which are vital in early IVD morphogenesis. Pax1 is up-regulated in the absence of Pax9, while Pax9 is unaffected by the loss of Pax1/Pax9. We identified the targets compensated by a single- or double-copy of Pax9. They positively regulate many of the cartilage genes known to be regulated by Sox5/Sox6/Sox9 and are connected to Sox5/Sox6 by a negative feedback loop. Pax1/Pax9 are intertwined with BMP and TGF-B pathways and we propose they initiate expression of chondrogenic genes during early IVD differentiation and subsequently become restricted to the outer annulus by the negative feedback mechanism. Our findings highlight how early IVD development is regulated spatio-temporally and have implications for understanding kyphoscoliosis.

  10. Modeling collisions in circumstellar debris disks

    Science.gov (United States)

    Nesvold, Erika

    2015-10-01

    Observations of resolved debris disks show a spectacular variety of features and asymmetries, including inner cavities and gaps, inclined secondary disks or warps, and eccentric, sharp-edged rings. Embedded exoplanets could create many of these features via gravitational perturbations, which sculpt the disk directly and by generating planetesimal collisions. In this thesis, I present the Superparticle Model/Algorithm for Collisions in Kuiper belts and debris disks (SMACK), a new method for simultaneously modeling, in 3-D, the collisional and dynamical evolution of planetesimals in a debris disk with planets. SMACK can simulate azimuthal asymmetries and how these asymmetries evolve over time. I show that SMACK is stable to numerical viscosity and numerical heating over 107 yr, and that it can reproduce analytic models of disk evolution. As an example of the algorithm's capabilities, I use SMACK to model the evolution of a debris ring containing a planet on an eccentric orbit and demonstrate that differential precession creates a spiral structure as the ring evolves, but collisions subsequently break up the spiral, leaving a narrower eccentric ring. To demonstrate SMACK's utility in studying debris disk physics, I apply SMACK to simulate a planet on a circular orbit near a ring of planetesimals that are experiencing destructive collisions. Previous simulations of a planet opening a gap in a collisionless debris disk have found that the width of the gap scales as the planet mass to the 2/7th power (alpha = 2/7). I find that gap sizes in a collisional disk still obey a power law scaling with planet mass, but that the index alpha of the power law depends on the age of the system t relative to the collisional timescale t coll of the disk by alpha = 0.32(t/ tcoll)-0.04, with inferred planet masses up to five times smaller than those predicted by the classical gap law. The increased gap sizes likely stem from the interaction between collisions and the mean motion

  11. The effect of cyclic compression on the mechanical properties of the inter-vertebral disc: an in vivo study in a rat tail model.

    Science.gov (United States)

    Ching, Congo T S; Chow, Daniel H K; Yao, Fiona Y D; Holmes, Andrew D

    2003-03-01

    To assess the changes in the mechanical properties of inter-vertebral discs in vivo following static and cyclic compressive loading of different frequencies. An in vivo biomechanical study using a rat-tail model of the inter-vertebral disc.Background. Mechanical loading has been suggested as playing a major role in the etiology of disc degeneration, but the relationship is still not fully understood. Sixty Sprague-Dawley rats were subject to daily compressive stress via pins inserted in the 6th and 7th caudal vertebrae over a two-week loading period. Animals were randomly divided into a sham group (pin insertion, no loading), a static loading group, or cyclic loading groups of 0.5, 1.5, or 2.5 Hz. Loading was applied for 1 h each day from the 3rd to 17th day following pin insertion, and the angular compliance, angular laxity, and inter-pin distance were measured in vivo at days 0, 3, 10 and 17. Changes in the inter-vertebral disc height depended on the frequency of loading, with the decrease in disc height in the static compression group significantly greater than that in all other groups, whereas the decrease in the 1.5 Hz cyclic compression group was significantly smaller than that in all other compression groups. Changes in disc properties depend on both the total load exposure and the frequency of loading. Cyclic loading in general produced less marked changes than static loading, but loading at particular frequencies may result in more severe changes. Previous studies have shown the in vivo changes in the mechanical properties of inter-vertebral discs to depend on the magnitude and duration of loading. In this study, a frequency dependent response to cyclic loading is also demonstrated.

  12. THREE-DIMENSIONAL DISK-PLANET TORQUES IN A LOCALLY ISOTHERMAL DISK

    International Nuclear Information System (INIS)

    D'Angelo, Gennaro; Lubow, Stephen H.

    2010-01-01

    We determine an expression for the Type I planet migration torque involving a locally isothermal disk, with moderate turbulent viscosity (5 x 10 -4 ∼< α ∼< 0.05), based on three-dimensional nonlinear hydrodynamical simulations. The radial gradients (in a dimensionless logarithmic form) of density and temperature are assumed to be constant near the planet. We find that the torque is roughly equally sensitive to the surface density and temperature radial gradients. Both gradients contribute to inward migration when they are negative. Our results indicate that two-dimensional calculations with a smoothed planet potential, used to account for the effects of the third dimension, do not accurately determine the effects of density and temperature gradients on the three-dimensional torque. The results suggest that substantially slowing or stopping planet migration by means of changes in disk opacity or shadowing is difficult and appears unlikely for a disk that is locally isothermal. The scalings of the torque and torque density with planet mass and gas sound speed follow the expectations of linear theory. We also determine an improved formula for the torque density distribution that can be used in one-dimensional long-term evolution studies of planets embedded in locally isothermal disks. This formula can be also applied in the presence of mildly varying radial gradients and of planets that open gaps. We illustrate its use in the case of migrating super-Earths and determine some conditions sufficient for survival.

  13. Angular momentum transfer in steady disk accretion

    International Nuclear Information System (INIS)

    Gorbatskij, V.G.

    1977-01-01

    The conditions of steady disk accretion have been investigated. The disk axisymmetric model is considered. It is shown that the gas is let at the outer boundary of the disk with the azimuthal velocity which is slightly less than the Kepler circular one. Gas possesses the motion quality moment which is transferred from the outer layers of the disk to the surface of the star. The steady state of the disk preserved until the inflow of the moment to the star increases its rotation velocity up to magnitudes close to the critical one

  14. Time-Dependent Variations of Accretion Disk

    Directory of Open Access Journals (Sweden)

    Hye-Weon Na

    1987-06-01

    Full Text Available In dward nova we assume the primary star as a white dwarf and the secondary as the late type star which filled Roche lobe. Mass flow from the secondary star leads to the formation of thin accretion disk around the white dwarf. We use the α parameter as viscosity to maintain the disk form and propose that the outburst in dwarf nova cause the steep increase of source term. With these assumptions we solve the basic equations of stellar structure using Newton-Raphson method. We show the physical parameters like temperature, density, pressure, opacity, surface density, height and flux to the radius of disk. Changing the value of α, we compare several parameters when mass flow rate is constant with those of when luminosity of disk is brightest. At the same time, we obtain time-dependent variations of luminosity and mass of disk. We propose the suitable range of α is 0.15-0.18 to the difference of luminosity. We compare several parameters of disk with those of the normal late type stars which have the same molecular weight of disk is lower. Maybe the outburst in dwarf nova is due to the variation of the α value instead of increment of mass flow from the secondary star.

  15. Overlapping of mononuclear cells derived from bone marrow in rats' intervertebral discs: an in vitro study Sobreposição de células mononucleares provenientes da medula óssea em disco intervertebral de ratos: estudo in vitro

    Directory of Open Access Journals (Sweden)

    Erica Batista Fontes

    2010-04-01

    Full Text Available In this study, bone marrow mononuclear cells (BM-MNC derived from rats were used in order to promote intervertebral disc regeneration. These cells were isolated after centrifugation in a Ficoll-Paque™ PLUS density gradient and then placed in plastic dishes to proliferate during a period of 14 days. The BM-MNCs were previously labeled with the fluorescent membrane marker Chloromethyl-benzamidodialkylcarbocyanine (CM-DIL, and thereafter were implanted in rats' intervertebral discs explants as an in vitro experimental model. Daily analyses of the cells under a fluorescence microscope revealed morphological changes, which assumed a thin and elongated shape similar to cells that originally form the annulus fibroses. Histopathological analysis demonstrated the presence of mononuclear cells interspersed within collagen fibers. The presence of viable cells, in which were found morphological changes and their disposal in the same pattern of the layers that originate the annulus fibrosus, is an indicator that they engrafted and proliferated on the intervertebral disc. Therefore, morphological changes presented by these cells indicate that they presented mesenchymal stem-like cell characteristics.Neste trabalho, foram utilizadas células mononucleares provenientes da medula óssea (MO de ratos para implantação em discos intervertebrais, a fim de estudar a sua participação em possível regeneração tecidual. Essas células foram obtidas por centrifugação, em gradiente de Ficoll-Paque™ PLUS, e cultivadas em frascos apropriados, por um período de 14 dias. Em etapa posterior, foram submetidas à marcação celular, em que foi utilizado o marcador citoplasmático CM-Dil, seguida de implantação em discos intervertebrais de ratos, em um sistema de cultivo in vitro. Foram feitas avaliações diárias dos discos com utilização de um microscópio de fluorescência, sendo constatadas alterações morfológicas com um formato alongado semelhante a c

  16. [Management of disk displacement with condylar fracture].

    Science.gov (United States)

    Yu, Shi-bin; Li, Zu-bing; Yang, Xue-wen; Zhao, Ji-hong; Dong, Yao-jun

    2003-07-01

    To investigate clinical features of disk displacement during the course of condylar fracture and to explore the techniques of disk reposition and suturation. 32 patients (10 females and 22 males) who had disk displacements with condylar fractures were followed up. Reduction and reposition of the dislocated disks simultaneously with fixation of fractures were performed. 7 patients underwent intermaxillary fixation with elastic bands for 1 to 2 weeks. The occlusions were satisfactory in all cases but one for the reason of ramus height loss. No TMJ symptom was found when examined 3 months post operation. Anterior disk displacements were most occurred with high condylar process fractures. Surgical reposition and suturation of disk play an important role for the later TMJ-function.

  17. Cervical spine degenerative changes (narrowed intervertebral disc spaces and osteophytes) in coal miners

    International Nuclear Information System (INIS)

    Zejda, J. E.; Stasiow, B.

    2003-01-01

    A series of 685 x-rays films of the cervical spine obtained in coal miners was analyzed to explore the occurrence of narrowed disc spaces and osteophytes in this occupational group, and to examine the association of x-rays changes with age, duration of employment, and duration of occupational exposure to hand-arm vibration. All data were extracted from individual medical files of coal miners examined for suspected hand-arm vibration-related disorders in 1989-1999 at the Occupational Medicine Center in Katowice. The narrowed intervertebral disc spaces were found in 188 coal miners (26.9%) and osteophytes in 332 coal miners (47.5%). The occurrence of degenerative changes in coal miners was similar to that observed in a small group of 68 blue-collar workers (no exposure to hand-arm vibration) employed in the coal industry. Univariate comparisons showed that intervertebral disc spaces and osteophytes were more frequent among older subjects and among subjects with longer duration of employment. The results of logistic regression analysis confirmed statistically significant effect of age, but not of other factors included in the model. When both x-ray changes were grouped together (a combined dependent variable) age remained the only statistically significant explanatory variable. The findings do not support the view that the examined degenerative changes in cervical spine are more prevalent in coal miners and depend on duration of physical work or local exposure to hand-arm vibration in this occupational group. (author)

  18. Dust evolution in protoplanetary disks

    OpenAIRE

    Gonzalez , Jean-François; Fouchet , Laure; T. Maddison , Sarah; Laibe , Guillaume

    2007-01-01

    6 pages, 5 figures, to appear in the Proceedings of IAU Symp. 249: Exoplanets: Detection, Formation and Dynamics (Suzhou, China); International audience; We investigate the behaviour of dust in protoplanetary disks under the action of gas drag using our 3D, two-fluid (gas+dust) SPH code. We present the evolution of the dust spatial distribution in global simulations of planetless disks as well as of disks containing an already formed planet. The resulting dust structures vary strongly with pa...

  19. Fallback disks & magnetars: prospects & possibilities

    Science.gov (United States)

    Alpar, M. A.

    Some bound matter in the form of a fallback disk may be an initial parameter of isolated neutron stars at birth which along with the initial rotation rate and dipole and higher multipole magnetic moments determines the evolution of neutron stars and the categories into which they fall This talk reviews the strengths and difficulties of fallback disk models in explaining properties of isolated neutron stars of different categories Evidence for and observational limits on fallback disks will also be discussed

  20. MIGRATION TRAPS IN DISKS AROUND SUPERMASSIVE BLACK HOLES

    Energy Technology Data Exchange (ETDEWEB)

    Bellovary, Jillian M.; Low, Mordecai-Mark Mac; McKernan, Barry; Ford, K. E. Saavik [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, NY 10024 (United States)

    2016-03-10

    Accretion disks around supermassive black holes (SMBHs) in active galactic nuclei (AGNs) contain stars, stellar mass black holes, and other stellar remnants, which perturb the disk gas gravitationally. The resulting density perturbations exert torques on the embedded masses causing them to migrate through the disk in a manner analogous to planets in protoplanetary disks. We determine the strength and direction of these torques using an empirical analytic description dependent on local disk gradients, applied to two different analytic, steady-state disk models of SMBH accretion disks. We find that there are radii in such disks where the gas torque changes sign, trapping migrating objects. Our analysis shows that major migration traps generally occur where the disk surface density gradient changes sign from positive to negative, around 20–300R{sub g}, where R{sub g} = 2GM/c{sup 2} is the Schwarzschild radius. At these traps, massive objects in the AGN disk can accumulate, collide, scatter, and accrete. Intermediate mass black hole formation is likely in these disk locations, which may lead to preferential gap and cavity creation at these radii. Our model thus has significant implications for SMBH growth as well as gravitational wave source populations.

  1. Circumstellar disks around binary stars in Taurus

    Energy Technology Data Exchange (ETDEWEB)

    Akeson, R. L. [NASA Exoplanet Science Institute, IPAC/Caltech, Pasadena, CA 91125 (United States); Jensen, E. L. N. [Swarthmore College, Department of Physics and Astronomy, Swarthmore, PA 19081 (United States)

    2014-03-20

    We have conducted a survey of 17 wide (>100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems as an aid to understanding the role of multiplicity in star and planet formation. The ALMA observations had sufficient resolution to localize emission within the binary system. Disk emission was detected around all primaries and 10 secondaries, with disk masses as low as 10{sup –4} M {sub ☉}. We compare the properties of our sample to the population of known disks in Taurus and find that the disks from this binary sample match the scaling between stellar mass and millimeter flux of F{sub mm}∝M{sub ∗}{sup 1.5--2.0} to within the scatter found in previous studies. We also compare the properties of the primaries to those of the secondaries and find that the secondary/primary stellar and disk mass ratios are not correlated; in three systems, the circumsecondary disk is more massive than the circumprimary disk, counter to some theoretical predictions.

  2. Calcification of intervertebral discs in the dachshund: a radiographic study of 21 stud-dogs

    International Nuclear Information System (INIS)

    Stigen, O.

    1995-01-01

    The vertebral columns of 21 clinically normal, 4.9 to 13.2 year old dachshunds were x-rayed. This sample represented 55.3% of all male dachshunds with 20 or more offspring registered with the Norwegian Kennel Club in the period 1985-1989. Calcified intervertebral discs were identified in 9 (42.9%) of the stud-dogs, and the number of calcified discs in each individual varied from 2 to 5 with a mean of 3.7. The frequency of stud-dogs with 1 or more calcified discs was compared with the corresponding frequency in a material of 327 one-year-old dachshunds. In this comparison, the relative risk was estimated with 95% confidence bounds. When the different composition of size and coat varieties in the 2 materials was not considered, the relative risk of calcified discs was found to be 1.77 (0.99-3.2) times higher in stud-dogs than in young dogs. When the different composition of varieties in the 2 materials was considered, the relative risk was found to be 1.9 (1.1-3.4) times higher in stud-dogs than in young dogs. The results of the present study strongly suggest that an increase in the frequency of dachshunds with 1 or more calcified intervertebral discs occurs after 1 year of age

  3. Evaluation of powder metallurgy superalloy disk materials

    Science.gov (United States)

    Evans, D. J.

    1975-01-01

    A program was conducted to develop nickel-base superalloy disk material using prealloyed powder metallurgy techniques. The program included fabrication of test specimens and subscale turbine disks from four different prealloyed powders (NASA-TRW-VIA, AF2-1DA, Mar-M-432 and MERL 80). Based on evaluation of these specimens and disks, two alloys (AF2-1DA and Mar-M-432) were selected for scale-up evaluation. Using fabricating experience gained in the subscale turbine disk effort, test specimens and full scale turbine disks were formed from the selected alloys. These specimens and disks were then subjected to a rigorous test program to evaluate their physical properties and determine their suitability for use in advanced performance turbine engines. A major objective of the program was to develop processes which would yield alloy properties that would be repeatable in producing jet engine disks from the same powder metallurgy alloys. The feasibility of manufacturing full scale gas turbine engine disks by thermomechanical processing of pre-alloyed metal powders was demonstrated. AF2-1DA was shown to possess tensile and creep-rupture properties in excess of those of Astroloy, one of the highest temperature capability disk alloys now in production. It was determined that metallographic evaluation after post-HIP elevated temperature exposure should be used to verify the effectiveness of consolidation of hot isostatically pressed billets.

  4. Role of hypoxia and growth and differentiation factor-5 on differentiation of human mesenchymal stem cells towards intervertebral nucleus pulposus-like cells

    Directory of Open Access Journals (Sweden)

    JV Stoyanov

    2011-06-01

    Full Text Available There is evidence that mesenchymal stem cells (MSCs can differentiate towards an intervertebral disc (IVD-like phenotype. We compared the standard chondrogenic protocol using transforming growth factor beta-1 (TGFß to the effects of hypoxia, growth and differentiation factor-5 (GDF5, and coculture with bovine nucleus pulposus cells (bNPC. The efficacy of molecules recently discovered as possible nucleus pulposus (NP markers to differentiate between chondrogenic and IVD-like differentiation was evaluated. MSCs were isolated from human bone marrow and encapsulated in alginate beads. Beads were cultured in DMEM (control supplemented with TGFß or GDF5 or under indirect coculture with bNPC. All groups were incubated at low (2 % or normal (20 % oxygen tension for 28 days. Hypoxia increased aggrecan and collagen II gene expression in all groups. The hypoxic GDF5 and TGFß groups demonstrated most increased aggrecan and collagen II mRNA levels and glycosaminoglycan accumulation. Collagen I and X were most up-regulated in the TGFß groups. From the NP markers, cytokeratin-19 was expressed to highest extent in the hypoxic GDF5 groups; lowest expression was observed in the TGFß group. Levels of forkhead box F1 were down-regulated by TGFß and up-regulated by coculture with bNPC. Carbonic anhydrase 12 was also down-regulated in the TGFß group and showed highest expression in the GDF5 group cocultured with bNPC under hypoxia. Trends in gene expression regulation were confirmed on the protein level using immunohistochemistry. We conclude that hypoxia and GDF5 may be suitable for directing MSCs towards the IVD-like phenotype.

  5. Percutaneous treatment of intervertebral disc herniation.

    Science.gov (United States)

    Buy, Xavier; Gangi, Afshin

    2010-06-01

    Interventional radiology plays a major role in the management of symptomatic intervertebral disc herniations. In the absence of significant pain relief with conservative treatment including oral pain killers and anti-inflammatory drugs, selective image-guided periradicular infiltrations are generally indicated. The precise control of needle positioning allows optimal distribution of steroids along the painful nerve root. After 6 weeks of failure of conservative treatment including periradicular infiltration, treatment aiming to decompress or remove the herniation is considered. Conventional open surgery offers suboptimal results and is associated with significant morbidity. To achieve minimally invasive discal decompression, different percutaneous techniques have been developed. Their principle is to remove a small volume of nucleus, which results in an important reduction of intradiscal pressure and subsequently reduction of pressure inside the disc herniation. However, only contained disc herniations determined by computed tomography or magnetic resonance are indicated for these techniques. Thermal techniques such as radiofrequency or laser nucleotomy seem to be more effective than purely mechanical nucleotomy; indeed, they achieve discal decompression but also thermal destruction of intradiscal nociceptors, which may play a major role in the physiopathology of discal pain. The techniques of image-guided spinal periradicular infiltration and percutaneous nucleotomy with laser and radiofrequency are presented with emphasis on their best indications.

  6. THE DISK IMAGING SURVEY OF CHEMISTRY WITH SMA. I. TAURUS PROTOPLANETARY DISK DATA

    International Nuclear Information System (INIS)

    Oeberg, Karin I.; Qi Chunhua; Andrews, Sean M.; Espaillat, Catherine; Van Kempen, Tim A.; Wilner, David J.; Fogel, Jeffrey K. J.; Bergin, Edwin A.; Pascucci, Ilaria

    2010-01-01

    Chemistry plays an important role in the structure and evolution of protoplanetary disks, with implications for the composition of comets and planets. This is the first of a series of papers based on data from DISCS, a Submillimeter Array survey of the chemical composition of protoplanetary disks. The six Taurus sources in the program (DM Tau, AA Tau, LkCa 15, GM Aur, CQ Tau, and MWC 480) range in stellar spectral type from M1 to A4 and offer an opportunity to test the effects of stellar luminosity on the disk chemistry. The disks were observed in 10 different lines at ∼3'' resolution and an rms of ∼100 mJy beam -1 at ∼0.5 km s -1 . The four brightest lines are CO 2-1, HCO + 3-2, CN 2 33/4/2 - 1 22/3/1 , and HCN 3-2, and these are detected toward all sources (except for HCN toward CQ Tau). The weaker lines of CN 2 22 -1 11 , DCO + 3-2, N 2 H + 3-2, H 2 CO 3 03 -2 02 , and 4 14 -3 13 are detected toward two to three disks each, and DCN 3-2 only toward LkCa 15. CH 3 OH 4 21 -3 1 2 and c-C 3 H 2 are not detected. There is no obvious difference between the T Tauri and Herbig Ae sources with regard to CN and HCN intensities. In contrast, DCO + , DCN, N 2 H + , and H 2 CO are detected only toward the T Tauri stars, suggesting that the disks around Herbig Ae stars lack cold regions for long enough timescales to allow for efficient deuterium chemistry, CO freeze-out, and grain chemistry.

  7. Simultaneous measurements of disk vibration and pressure fluctuation in turbulent flow developing in a model hard disk drive

    Energy Technology Data Exchange (ETDEWEB)

    Kurashima, D.; Naka, Y.; Fukagata, K. [Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Obi, S., E-mail: obsn@mech.keio.ac.jp [Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

    2011-06-15

    The complex flow features inside hard disk drive models are investigated in an axisymmetric and a semi-open shroud configurations. For the axisymmetric case, we have employed both experimental and computational approaches. The experiment focuses on both flow dynamics and the disk vibration, where measurements of the fluctuating pressure and velocity are undertaken at some representative points. The correlation between the disk vibration and the fluctuating pressure in the turbulent flow between disks is evident from the spectral analysis. The experimentally observed fluctuating pressure and velocity are partly due to the disk vibration and its contribution could be estimated by comparing the experiment with the results of a large eddy simulation. For the semi-open shroud case, although the characteristic peaks attributable to the large-scale vortical structure are still observed in the power spectra, the pressure fluctuation and the disk vibration are suppressed when the arm is inserted.

  8. MOLECULAR DISK PROPERTIES IN EARLY-TYPE GALAXIES

    International Nuclear Information System (INIS)

    Xu, X.; Walker, C.; Narayanan, D.

    2010-01-01

    We study the simulated CO emission from elliptical galaxies formed in the mergers of gas-rich disk galaxies. The cold gas not consumed in the merger-driven starburst quickly resettles into a disk-like configuration. By analyzing a variety of arbitrary merger orbits that produce a range of fast- to slow-rotating remnants, we find that molecular disk formation is a fairly common consequence of gas-rich galaxy mergers. Hence, if a molecular disk is observed in an early-type merger remnant, it is likely the result of a 'wet merger' rather than a 'dry merger'. We compare the physical properties from our simulated disks (e.g., size and mass) and find reasonably good agreement with recent observations. Finally, we discuss the detectability of these disks as an aid to future observations.

  9. Rotation of gas above the galactic disk

    International Nuclear Information System (INIS)

    Gvaramadze, V.V.; Lominadze, D.G.

    1988-01-01

    The galactic disk is modeled by an oblate spheroid with confocal spherodial isodensity surfaces. An explicit analytic expression is found for the angular velocity of the gas outside the disk. The parameters of a three-component model of a spiral galaxy (oblate spheroid with central hole, bulge, and massive corona) are chosen in such a way as to obtain in the disk a two-hump rotation curve (as in the Galaxy, M 31, and M 81). It is shown that at heights absolute value z ≤ 2 kpc the gas rotates in the same manner as the disk. However, at greater heights the rotation curve ceases to have two humps. Allowance for the pressure gradient of the gas slightly changes the rotation curve directly above the disk (r r/sub disk/)

  10. Studies of Young, Star-forming Circumstellar Disks

    Science.gov (United States)

    Bae, Jaehan

    2017-08-01

    Disks of gas and dust around forming stars - circumstellar disks - last only a few million years. This is a very small fraction of the entire lifetime of Sun-like stars, several billion years. Nevertheless, by the time circumstellar disks dissipate stars complete building up their masses, giant planets finish accreting gas, and terrestrial bodies are nearly fully grown and ready for their final assembly to become planets. Understanding the evolution of circumstellar disks are thus crucial in many contexts. Using numerical simulations as the primary tool, my thesis has focused on the studies of various physical processes that can occur throughout the lifetime of circumstellar disks, from their formation to dispersal. Chapters 2, 3, and 4 emphasize the importance of early evolution, during which time a forming star-disk system obtains mass from its natal cloud: the infall phase. In Chapter 2 and 3, I have modeled episodic outbursts of accretion in protostellar systems resulting from disk instabilities - gravitational instability and magnetorotational instability. I showed that outbursts occur preferentially during the infall phase, because the mass addition provides more favorable conditions for gravitational instability to initiate the outburst cycle, and that forming stars build up a significant fraction of their masses through repeated short-lived, episodic outbursts. The infall phase can also be important for the formation of planets. Recent ALMA observations revealed sets of bright and dark rings in circumstellar disks of young, forming stars, potentially indicating early formation of planets. In Chapter 4, I showed that infall streams can create radial pressure bumps near the outer edge of the mass landing on the disk, from which vortices can form, collecting solid particles very efficiently to make initial seeds of planets. The next three chapters highlight the role of planets in setting the observational appearance and the evolution of circumstellar disks

  11. Dynamics of acoustically levitated disk samples.

    Science.gov (United States)

    Xie, W J; Wei, B

    2004-10-01

    The acoustic levitation force on disk samples and the dynamics of large water drops in a planar standing wave are studied by solving the acoustic scattering problem through incorporating the boundary element method. The dependence of levitation force amplitude on the equivalent radius R of disks deviates seriously from the R3 law predicted by King's theory, and a larger force can be obtained for thin disks. When the disk aspect ratio gamma is larger than a critical value gamma(*) ( approximately 1.9 ) and the disk radius a is smaller than the critical value a(*) (gamma) , the levitation force per unit volume of the sample will increase with the enlargement of the disk. The acoustic levitation force on thin-disk samples ( gammaacoustic field for stable levitation of a large water drop is to adjust the reflector-emitter interval H slightly above the resonant interval H(n) . The simulation shows that the drop is flattened and the central parts of its top and bottom surface become concave with the increase of sound pressure level, which agrees with the experimental observation. The main frequencies of the shape oscillation under different sound pressures are slightly larger than the Rayleigh frequency because of the large shape deformation. The simulated translational frequencies of the vertical vibration under normal gravity condition agree with the theoretical analysis.

  12. Comparison of Rosco Neo-Sensitabs with Oxoid paper disks in EUCAST disk diffusion antimicrobial susceptibility testing on Mueller-Hinton agar

    DEFF Research Database (Denmark)

    Justesen, U S; Acar, Ziyap; Olsson, K

    2013-01-01

    This study compared Neo-Sensitabs with Oxoid paper disks using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) disk diffusion antimicrobial susceptibility test on Mueller-Hinton agar. The EUCAST-recommended quality control strains (Escherichia coli ATCC 25922, Pseudomonas...... paper disks for EUCAST disk diffusion antimicrobial susceptibility testing on Mueller-Hinton agar....

  13. Working with arrays of inexpensive EIDE disk drives

    International Nuclear Information System (INIS)

    Sanders, D.; Riley, C.; Cremaldi, L.; Summers, D.; Petravick, D.

    2000-01-01

    In today's marketplace, the cost per Terabyte of disks with EIDE interfaces is about a third that of disks with SCSI. Hence, three times as many particle physics events could be put online with EIDE. The modern EIDE interface includes many of the performance features that appeared earlier in SCSI. EIDE bus speeds approach 33 Megabytes/s and need only be shared between two disks rather than seven disks. The interal I/O rate of very fast (and expensive) SCSI disks is only 50% greater than EIDE disks. Hence, two EIDE disks whose combined cost is much less than one very fast SCSI disk can actually give more data throughput due to the advantage of multiple spindles and head actuators. The authors explore the use of 12 and 16 Gigabyte EIDE disks with motherboard and PCI bus card interfaces on a number of operating systems and CPUs. These include Red Hat Linux and Windows 95/98 on a Pentium, MacOS and Apple's Rhapsody/NeXT/UNIX on a PowerPC, and Sun Solaris on a UltraSparc 10 workstation

  14. Ultrafast disk lasers and amplifiers

    Science.gov (United States)

    Sutter, Dirk H.; Kleinbauer, Jochen; Bauer, Dominik; Wolf, Martin; Tan, Chuong; Gebs, Raphael; Budnicki, Aleksander; Wagenblast, Philipp; Weiler, Sascha

    2012-03-01

    Disk lasers with multi-kW continuous wave (CW) output power are widely used in manufacturing, primarily for cutting and welding applications, notably in the automotive industry. The ytterbium disk technology combines high power (average and/or peak power), excellent beam quality, high efficiency, and high reliability with low investment and operating costs. Fundamental mode picosecond disk lasers are well established in micro machining at high throughput and perfect precision. Following the world's first market introduction of industrial grade 50 W picosecond lasers (TruMicro 5050) at the Photonics West 2008, the second generation of the TruMicro series 5000 now provides twice the average power (100 W at 1030 nm, or 60 W frequency doubled, green output) at a significantly reduced footprint. Mode-locked disk oscillators achieve by far the highest average power of any unamplified lasers, significantly exceeding the 100 W level in laboratory set-ups. With robust long resonators their multi-microjoule pulse energies begin to compete with typical ultrafast amplifiers. In addition, significant interest in disk technology has recently come from the extreme light laser community, aiming for ultra-high peak powers of petawatts and beyond.

  15. Roentgenological and scintigraphic findings in alkaptonuric ochronosis

    International Nuclear Information System (INIS)

    Zocholl, G.; Schild, H.; Roehrborn, W.; Kraus, W.; Ballo, H.

    1986-01-01

    In alkaptonuria, a recessively inherited disturbance of amino acid metabolism, deposits of oxydation products of homogentisinic acid result in the disease pattern of ochronosis. Due to the enhanced brittleness of the supporting and gliding tissue, ochronotic arthropathy develops at the vertebral column and later at the major joints with typical roentgenological changes especially in the intervertebral space and the intervertebral disk, as well as the adjacent vertebral bodies. The bone scintigram shows enhanced accumulation in the base and tectorial plates as well as in the adjacent sclerosing zones in the spongiosa of the affected vertebral bodies. (orig.) [de

  16. Roentgenological and scintigraphic findings in alkaptonuric ochronosis

    Energy Technology Data Exchange (ETDEWEB)

    Zocholl, G.; Schild, H.; Roehrborn, W.; Kraus, W.; Ballo, H.

    1986-04-01

    In alkaptonuria, a recessively inherited disturbance of amino acid metabolism, deposits of oxydation products of homogentisinic acid result in the disease pattern of ochronosis. Due to the enhanced brittleness of the supporting and gliding tissue, ochronotic arthropathy develops at the vertebral column and later at the major joints with typical roentgenological changes especially in the intervertebral space and the intervertebral disk, as well as the adjacent vertebral bodies. The bone scintigram shows enhanced accumulation in the base and tectorial plates as well as in the adjacent sclerosing zones in the spongiosa of the affected vertebral bodies.

  17. Equilibrium figures for beta Lyrae type disks

    International Nuclear Information System (INIS)

    Wilson, R.E.

    1981-01-01

    Accumulated evidence for a geometrically and optically thick disk in the β Lyrae system has now established the disk's basic external configuration. Since the disk has been constant in its main properties over the historical interval of β Lyrae observations and also seems to have a basically well-defined photosphere, it is now time to being consideration of its sturcture. Here, we compute equilibrium figures for self-gravitating disks around stars in binary systems as a start toward eventual computation of complete disk models. A key role is played by centrifugally limited rotation of the central star, which would naturally arise late in the rapid phase of mass transfer. Beta Lyrae is thus postulated to be a double-contact binary, which makes possible nonarbitrary separation of star and disk into separate structures. The computed equilibrium figures are three-dimensional, as the gravitation of the second star is included. Under the approximation that the gravitational potential of the disk is that of a thin wire and that the local disk angular velocity is proportional to u/sup n/ (u = distance from rotation axis), we comptue the total potential and locate equipotential surfaces. The centrifugal potential is written in a particularly convenient form which permits one to change the rotation law discontinuously (for example, at the star-disk coupling point) while ensuring that centrifugal potential and centrifigual force are continuous functions of position. With such a one-parameter rotation law, one can find equilibrium disk figures with dimensions very similar to those found in β Lyrae, but considerations of internal consistency demand at least a two-parameter law

  18. Recent development of disk lasers at TRUMPF

    Science.gov (United States)

    Schad, Sven-Silvius; Gottwald, Tina; Kuhn, Vincent; Ackermann, Matthias; Bauer, Dominik; Scharun, Michael; Killi, Alexander

    2016-03-01

    The disk laser is one of the most important laser concepts for today's industrial laser market. Offering high brilliance at low cost, high optical efficiency and great application flexibility the disk laser paved the way for many industrial laser applications. Over the past years power and brightness increased and the disk laser turned out to be a very versatile laser source, not only for welding but also for cutting. Both, the quality and speed of cutting are superior to CO2-based lasers for a vast majority of metals, and, most important, in a broad thickness range. In addition, due to the insensitivity against back reflections the disk laser is well suited for cutting highly reflective metal such as brass or copper. These advantages facilitate versatile cutting machines and explain the high and growing demand for disk lasers for applications besides welding applications that can be observed today. From a today's perspective the disk principle has not reached any fundamental limits regarding output power per disk or beam quality, and offers numerous advantages over other high power resonator concepts, especially over fiber lasers or direct diode lasers. This paper will give insight in the latest progress in kilowatt class cw disk laser technology at TRUMPF and will discuss recent power scaling results as well.

  19. Radiative Transfer Modeling in Proto-planetary Disks

    Science.gov (United States)

    Kasper, David; Jang-Condell, Hannah; Kloster, Dylan

    2016-01-01

    Young Stellar Objects (YSOs) are rich astronomical research environments. Planets form in circumstellar disks of gas and dust around YSOs. With ever increasing capabilities of the observational instruments designed to look at these proto-planetary disks, most notably GPI, SPHERE, and ALMA, more accurate interfaces must be made to connect modeling of the disks with observation. PaRTY (Parallel Radiative Transfer in YSOs) is a code developed previously to model the observable density and temperature structure of such a disk by self-consistently calculating the structure of the disk based on radiative transfer physics. We present upgrades we are implementing to the PaRTY code to improve its accuracy and flexibility. These upgrades include: creating a two-sided disk model, implementing a spherical coordinate system, and implementing wavelength-dependent opacities. These upgrades will address problems in the PaRTY code of infinite optical thickness, calculation under/over-resolution, and wavelength-independent photon penetration depths, respectively. The upgraded code will be used to better model disk perturbations resulting from planet formation.

  20. A 100 au Wide Bipolar Rotating Shell Emanating from the HH 212 Protostellar Disk: A Disk Wind?

    Science.gov (United States)

    Lee, Chin-Fei; Li, Zhi-Yun; Codella, Claudio; Ho, Paul T. P.; Podio, Linda; Hirano, Naomi; Shang, Hsien; Turner, Neal J.; Zhang, Qizhou

    2018-03-01

    HH 212 is a Class 0 protostellar system found to host a “hamburger”-shaped dusty disk with a rotating disk atmosphere and a collimated SiO jet at a distance of ∼400 pc. Recently, a compact rotating outflow has been detected in SO and SO2 toward the center along the jet axis at ∼52 au (0.″13) resolution. Here we resolve the compact outflow into a small-scale wide-opening rotating outflow shell and a collimated jet, with the observations in the same S-bearing molecules at ∼16 au (0.″04) resolution. The collimated jet is aligned with the SiO jet, tracing the shock interactions in the jet. The wide-opening outflow shell is seen extending out from the inner disk around the SiO jet and has a width of ∼100 au. It is not only expanding away from the center, but also rotating around the jet axis. The specific angular momentum of the outflow shell is ∼40 au km s‑1. Simple modeling of the observed kinematics suggests that the rotating outflow shell can trace either a disk wind or disk material pushed away by an unseen wind from the inner disk or protostar. We also resolve the disk atmosphere in the same S-bearing molecules, confirming the Keplerian rotation there.

  1. Chemical evolution of the galactic disk

    International Nuclear Information System (INIS)

    Wyse, R.F.G.; Gilmore, G.

    1987-01-01

    The distribution of enriched material in the stars and gas of their Galaxy contains information pertaining to the chemical evolution of the Milky Way from its formation epoch to the present day, and provides general constraints on theories of galaxy formation. The separate stellar components of the Galaxy cannot readily be understood if treated in isolation, but a reasonably self-consistent model for Galactic chemical evolution may be found if one considers together the chemical properties of the extreme spheroid, thick disk and thin disk populations of the Galaxy. The three major stellar components of the Galaxy are characterized by their distinct spatial distributions, metallicity structure, and kinematics, with the newly-identified thick disk being approximately three times more massive than the classical metal-poor, non-rotating extreme spheroid. Stellar evolution in the thick disk straightforwardly provides the desired pre-enrichment for resolution of the thin disk G dwarf problem

  2. DUST DISTRIBUTION IN THE β PICTORIS CIRCUMSTELLAR DISKS

    International Nuclear Information System (INIS)

    Ahmic, Mirza; Croll, Bryce; Artymowicz, Pawel

    2009-01-01

    We present three-dimensional models of dust distribution around β Pictoris that produce the best fits to the Hubble Space Telescope/Advanced Camera for Surveys' images obtained by Golimowski and coworkers. We allow for the presence of either one or two separate axisymmetric dust disks. The density models are analytical, radial two power laws joined smoothly at a crossover radius with density exponentially decreasing away from the midplane of the disks. Two-disk models match the data best, yielding a reduced χ 2 of ∼1.2. Our two-disk model reproduces many of the asymmetries reported in the literature and suggests that it is the secondary (tilted) disk which is largely responsible for them. Our model suggests that the secondary disk is not constrained to the inner regions of the system (extending out to at least 250 AU) and that it has a slightly larger total area of dust than the primary, as a result of slower falloff of density with radius and height. This surprising result raises many questions about the origin and dynamics of such a pair of disks. The disks overlap, but can coexist owing to their low optical depths and therefore long mean collision times. We find that the two disks have dust replenishment times on the order of 10 4 yr at ∼100 AU, hinting at the presence of planetesimals that are responsible for the production of second generation dust. A plausible conjecture, which needs to be confirmed by physical modeling of the collisional dynamics of bodies in the disks, is that the two observed disks are derived from underlying planetesimal disks; such disks would be anchored by the gravitational influence of planets located at less than 70 AU from β Pic that are themselves in slightly inclined orbits.

  3. Thermal Comptonization in standard accretion disks

    International Nuclear Information System (INIS)

    Maraschi, L.; Molendi, S.

    1990-01-01

    Using the theory of geometrically thin accretion disks (where the effects of viscosity are parametrized in terms of the total pressure, viscosity parameter, α) equations are presented for the innermost region of the disk (where the pressure is due to radiation, and the main source of opacity is Thompson scattering). It is important to stress that the four equations can be solved without making use of an equation for the temperature. This is not true for the other regions of the disk. An equation given is used to determine the temperature, assuming that the disk is homogeneous and isothermal in the vertical direction. (author)

  4. Island universes structure and evolution of disk galaxies

    CERN Document Server

    DE JONG, R. S

    2007-01-01

    This book contains an up-to-date review of the structure and evolution of disk galaxies from both the observational and theoretical point of view. The book is the proceedings of the "Island Universes" conference held at the island of Terschelling, The Netherlands in July 2005, which attracted about 130 experts and students in the field. The conference was organized as a tribute to Dr. Piet C. van der Kruit for receiving the honorary Jacobus C. Kapteyn Professorship in Astronomy. The eight topical themes discussed at the meeting are reflected in these proceedings: 1) Properties of Stellar Disks, 2) Kinematics and Dynamics of Disk Galaxies, 3) Bars, Spiral Structure, and Secular Evolution in Disk Galaxies, 4) The Outskirts and Environment of Disk Galaxies, 5) Interstellar Matter, 6) (Evolution of) Star Formation in Galactic Disks, 7) Disk Galaxies through Cosmic Time, and 8) Formation Models of Disk Galaxies. These proceedings are concluded with a conference summary reflecting on the most significant recent pro...

  5. The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs.

    Directory of Open Access Journals (Sweden)

    Michael P Taylor

    Full Text Available The necks of sauropod dinosaurs were a key factor in their evolution. The habitual posture and range of motion of these necks has been controversial, and computer-aided studies have argued for an obligatory sub-horizontal pose. However, such studies are compromised by their failure to take into account the important role of intervertebral cartilage. This cartilage takes very different forms in different animals. Mammals and crocodilians have intervertebral discs, while birds have synovial joints in their necks. The form and thickness of cartilage varies significantly even among closely related taxa. We cannot yet tell whether the neck joints of sauropods more closely resembled those of birds or mammals. Inspection of CT scans showed cartilage:bone ratios of 4.5% for Sauroposeidon and about 20% and 15% for two juvenile Apatosaurus individuals. In extant animals, this ratio varied from 2.59% for the rhea to 24% for a juvenile giraffe. It is not yet possible to disentangle ontogenetic and taxonomic signals, but mammal cartilage is generally three times as thick as that of birds. Our most detailed work, on a turkey, yielded a cartilage:bone ratio of 4.56%. Articular cartilage also added 11% to the length of the turkey's zygapophyseal facets. Simple image manipulation suggests that incorporating 4.56% of neck cartilage into an intervertebral joint of a turkey raises neutral posture by 15°. If this were also true of sauropods, the true neutral pose of the neck would be much higher than has been depicted. An additional 11% of zygapophyseal facet length translates to 11% more range of motion at each joint. More precise quantitative results must await detailed modelling. In summary, including cartilage in our models of sauropod necks shows that they were longer, more elevated and more flexible than previously recognised.

  6. The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs.

    Science.gov (United States)

    Taylor, Michael P; Wedel, Mathew J

    2013-01-01

    The necks of sauropod dinosaurs were a key factor in their evolution. The habitual posture and range of motion of these necks has been controversial, and computer-aided studies have argued for an obligatory sub-horizontal pose. However, such studies are compromised by their failure to take into account the important role of intervertebral cartilage. This cartilage takes very different forms in different animals. Mammals and crocodilians have intervertebral discs, while birds have synovial joints in their necks. The form and thickness of cartilage varies significantly even among closely related taxa. We cannot yet tell whether the neck joints of sauropods more closely resembled those of birds or mammals. Inspection of CT scans showed cartilage:bone ratios of 4.5% for Sauroposeidon and about 20% and 15% for two juvenile Apatosaurus individuals. In extant animals, this ratio varied from 2.59% for the rhea to 24% for a juvenile giraffe. It is not yet possible to disentangle ontogenetic and taxonomic signals, but mammal cartilage is generally three times as thick as that of birds. Our most detailed work, on a turkey, yielded a cartilage:bone ratio of 4.56%. Articular cartilage also added 11% to the length of the turkey's zygapophyseal facets. Simple image manipulation suggests that incorporating 4.56% of neck cartilage into an intervertebral joint of a turkey raises neutral posture by 15°. If this were also true of sauropods, the true neutral pose of the neck would be much higher than has been depicted. An additional 11% of zygapophyseal facet length translates to 11% more range of motion at each joint. More precise quantitative results must await detailed modelling. In summary, including cartilage in our models of sauropod necks shows that they were longer, more elevated and more flexible than previously recognised.

  7. Nuclear magnetic resonance tomography of the cervical canal

    International Nuclear Information System (INIS)

    Terwey, B.; Koschorek, F.; Jensen, H.P.

    1985-01-01

    170 patients with suspected lesions of the cervical part of the medulla were examined using nuclear magnetic resonance (NMR) tomography. 27 cases revealed no pathological changes in the regions of the cervical medulla, the cervical canal and of the cervical spine. 143 cases produced pathological findings whose diagnoses determined therapeutical approach. Verified pathological changes comprised anomalies of the cranio-cervical junction like basilar impression and Arnold-Chiari malformation, various types of cavity formation in the cervical medulla (syringomyelia, hydromyelia), demyelinization processes, intramedullary and extramedullary tumours, intervertebral disk degeneration processes, dislocation of intervertebral disks and spondylophytes with spinal stenoses. Sagittal sections in different functional positions allowed to demonstrate the biomechanical effects of extramedullary masses on the cervical medulla. However, proven tumours could not be differentiated successfully using histological methods. Nevertheless, NMR tomography will replace invasive methods like conventional cervical myelography and CT myelography in diagnostic clarification of diseases of the cervical medulla. (orig.) [de

  8. Ochronotic Arthropathy: Two Case Reports from a Developing Country

    Directory of Open Access Journals (Sweden)

    Farooq A. Rathore

    2016-01-01

    Full Text Available Alkaptonuria is a rare inborn error of metabolism, which is classified as an orphan disease. It is due to the lack of an enzyme homogentisate 1,2-dioxygenase, which results in an accumulation of homogentisic acid in different areas of the body, including sclera, skin, cardiac valves, articular cartilage of the large joints and intervertebral disks. We present two cases of alkaptonuria resulting in ochronotic arthropathy with advanced secondary generalized osteoarthritis, intervertebral disk calcifications, skin and scleral pigmentation. In these case reports, both patients had symptoms for >10 years before being diagnosed. Conservative management in the form of high-dose ascorbic acid, exercises, and gait aids was offered to both of them, which resulted in some symptomatic improvement in the first case, while the second case was lost to follow-up. Alkaptonuria is a rare disease, and although it does not clearly impact mortality, early diagnosis may improve the quality of life.

  9. Relationships between Paraspinal Muscle Activity and Lumbar Inter-Vertebral Range of Motion

    Directory of Open Access Journals (Sweden)

    Alister du Rose

    2016-01-01

    Full Text Available Control of the lumbar spine requires contributions from both the active and passive sub-systems. Identifying interactions between these systems may provide insight into the mechanisms of low back pain. However, as a first step it is important to investigate what is normal. The purpose of this study was to explore the relationships between the lumbar inter-vertebral range of motion and paraspinal muscle activity during weight-bearing flexion in healthy controls using quantitative fluoroscopy (QF and surface electromyography (sEMG. Contemporaneous lumbar sEMG and QF motion sequences were recorded during controlled active flexion of 60° using electrodes placed over Longissimus thoracis pars thoracis (TES, Longissimus thoracis pars lumborum (LES, and Multifidus (LMU. Normalised root mean square (RMS sEMG amplitude data were averaged over five epochs, and the change in amplitude between epochs was calculated. The sEMG ratios of LMU/LES LMU/TES and LES/TES were also determined. QF was used to measure the maximum inter-vertebral range of motion from L2-S1, and correlation coefficients were calculated between sEMG amplitude variables and these measurements. Intra- and inter-session sEMG amplitude repeatability was also assessed for all three paraspinal muscles. The sEMG amplitude measurements were highly repeatable, and sEMG amplitude changes correlated significantly with L4-5 and L5-S1 IV-RoMmax (r = −0.47 to 0.59. The sEMG amplitude ratio of LES/TES also correlated with L4-L5 IV-RoMmax (r = −0.53. The relationships found may be important when considering rehabilitation for low back pain.

  10. Relationships between Paraspinal Muscle Activity and Lumbar Inter-Vertebral Range of Motion.

    Science.gov (United States)

    du Rose, Alister; Breen, Alan

    2016-01-05

    Control of the lumbar spine requires contributions from both the active and passive sub-systems. Identifying interactions between these systems may provide insight into the mechanisms of low back pain. However, as a first step it is important to investigate what is normal. The purpose of this study was to explore the relationships between the lumbar inter-vertebral range of motion and paraspinal muscle activity during weight-bearing flexion in healthy controls using quantitative fluoroscopy (QF) and surface electromyography (sEMG). Contemporaneous lumbar sEMG and QF motion sequences were recorded during controlled active flexion of 60° using electrodes placed over Longissimus thoracis pars thoracis (TES), Longissimus thoracis pars lumborum (LES), and Multifidus (LMU). Normalised root mean square (RMS) sEMG amplitude data were averaged over five epochs, and the change in amplitude between epochs was calculated. The sEMG ratios of LMU/LES LMU/TES and LES/TES were also determined. QF was used to measure the maximum inter-vertebral range of motion from L2-S1, and correlation coefficients were calculated between sEMG amplitude variables and these measurements. Intra- and inter-session sEMG amplitude repeatability was also assessed for all three paraspinal muscles. The sEMG amplitude measurements were highly repeatable, and sEMG amplitude changes correlated significantly with L4-5 and L5-S1 IV-RoMmax (r = -0.47 to 0.59). The sEMG amplitude ratio of LES/TES also correlated with L4-L5 IV-RoMmax (r = -0.53). The relationships found may be important when considering rehabilitation for low back pain.

  11. RED FRACTION AMONG SATELLITE GALAXIES WITH DISK-LIKE LIGHT PROFILES: EVIDENCE FOR INFLOW IN THE H I DISK

    International Nuclear Information System (INIS)

    Hester, J. A.

    2010-01-01

    The relationships between color, characterized with respect to the g - r red sequence; stellar structure, as determined using the i-band Sersic index; and group membership are explored using the Sloan Digital Sky Survey (SDSS). The new results place novel constraints on theories of galaxy evolution, despite the strong correlation between color and stellar structure. Observed correlations are of three independent types-those based on stellar structure, on the color of disk-like galaxies, and on the color of elliptical galaxies. Of particular note, the fraction of galaxies residing on the red sequence measured among galaxies with disk-like light profiles is enhanced for satellite galaxies compared to central galaxies. This fraction increases with group mass. When these new results are considered, theoretical treatments of galaxy evolution that adopt a gas accretion model centered on the hot galactic halo cannot consistently account for all observations of disk galaxies. The hypothesis is advanced that inflow within the extended H I disk prolongs star formation in satellite galaxies. When combined with partial ram pressure stripping (RPS) of this disk, this new scenario is consistent with the observations. This is demonstrated by applying an analytical model of RPS of the extended H I disk to the SDSS groups. These results motivate incorporating more complex modes of gas accretion into models of galaxy evolution, including cold mode accretion, an improved treatment of gas dynamics within disks, and disk stripping.

  12. On the Solar System-Debris Disk Connecction

    OpenAIRE

    Moro-Martin, Amaya

    2007-01-01

    This paper emphasizes the connection between solar and extra-solar debris disks: how models and observations of the Solar System are helping us understand the debris disk phenomenon, and vice versa, how debris disks are helping us place our Solar System into context.

  13. EARTH, MOON, SUN, AND CV ACCRETION DISKS

    International Nuclear Information System (INIS)

    Montgomery, M. M.

    2009-01-01

    Net tidal torque by the secondary on a misaligned accretion disk, like the net tidal torque by the Moon and the Sun on the equatorial bulge of the spinning and tilted Earth, is suggested by others to be a source to retrograde precession in non-magnetic, accreting cataclysmic variable (CV) dwarf novae (DN) systems that show negative superhumps in their light curves. We investigate this idea in this work. We generate a generic theoretical expression for retrograde precession in spinning disks that are misaligned with the orbital plane. Our generic theoretical expression matches that which describes the retrograde precession of Earths' equinoxes. By making appropriate assumptions, we reduce our generic theoretical expression to those generated by others, or to those used by others, to describe retrograde precession in protostellar, protoplanetary, X-ray binary, non-magnetic CV DN, quasar, and black hole systems. We find that spinning, tilted CV DN systems cannot be described by a precessing ring or by a precessing rigid disk. We find that differential rotation and effects on the disk by the accretion stream must be addressed. Our analysis indicates that the best description of a retrogradely precessing spinning, tilted, CV DN accretion disk is a differentially rotating, tilted disk with an attached rotating, tilted ring located near the innermost disk annuli. In agreement with the observations and numerical simulations by others, we find that our numerically simulated CV DN accretion disks retrogradely precess as a unit. Our final, reduced expression for retrograde precession agrees well with our numerical simulation results and with selective observational systems that seem to have main-sequence secondaries. Our results suggest that a major source to retrograde precession is tidal torques like that by the Moon and the Sun on the Earth. In addition, these tidal torques should be common to a variety of systems where one member is spinning and tilted, regardless if

  14. THE INNER DISK STRUCTURE, DISK-PLANET INTERACTIONS, AND TEMPORAL EVOLUTION IN THE β PICTORIS SYSTEM: A TWO-EPOCH HST/STIS CORONAGRAPHIC STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Apai, Dániel; Schneider, Glenn [Department of Astronomy and Steward Observatory, The University of Arizona, Tucson, AZ 85721 (United States); Grady, Carol A. [Eureka Scientific, 2452 Delmer, Suite 100, Oakland CA 96002 (United States); Wyatt, Mark C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Lagrange, Anne-Marie [Université Grenoble Alpes, IPAG, F-38000, Grenoble (France); Kuchner, Marc J.; Stark, Christopher J. [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics Laboratory, Code 667, Greenbelt, MD 20771 (United States); Lubow, Stephen H., E-mail: apai@arizona.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2015-02-20

    We present deep Hubble Space Telescope/Space Telescope Imaging Spectrograph coronagraphic images of the β Pic debris disk obtained at two epochs separated by 15 yr. The new images and the re-reduction of the 1997 data provide the most sensitive and detailed views of the disk at optical wavelengths as well as the yet smallest inner working angle optical coronagraphic image of the disk. Our observations characterize the large-scale and inner-disk asymmetries and we identify multiple breaks in the disk radial surface brightness profile. We study in detail the radial and vertical disk structure and show that the disk is warped. We explore the disk at the location of the β Pic b super-Jupiter and find that the disk surface brightness slope is continuous between 0.''5 and 2.''0, arguing for no change at the separations where β Pic b orbits. The two epoch images constrain the disk's surface brightness evolution on orbital and radiation pressure blow-out timescales. We place an upper limit of 3% on the disk surface brightness change between 3'' and 5'', including the locations of the disk warp, and the CO and dust clumps. We discuss the new observations in the context of high-resolution multi-wavelength images and divide the disk asymmetries in two groups: axisymmetric and non-axisymmetric. The axisymmetric structures (warp, large-scale butterfly, etc.) are consistent with disk structure models that include interactions of a planetesimal belt and a non-coplanar giant planet. The non-axisymmetric features, however, require a different explanation.

  15. THE DARK DISK OF THE MILKY WAY

    International Nuclear Information System (INIS)

    Purcell, Chris W.; Bullock, James S.; Kaplinghat, Manoj

    2009-01-01

    Massive satellite accretions onto early galactic disks can lead to the deposition of dark matter in disk-like configurations that co-rotate with the galaxy. This phenomenon has potentially dramatic consequences for dark matter detection experiments. We utilize focused, high-resolution simulations of accretion events onto disks designed to be Galaxy analogues, and compare the resultant disks to the morphological and kinematic properties of the Milky Way's thick disk in order to bracket the range of co-rotating accreted dark matter. In agreement with previous results, we find that the Milky Way's merger history must have been unusually quiescent compared to median Λ cold dark matter expectations and, therefore, its dark disk must be relatively small: the fraction of accreted dark disk material near the Sun is about 20% of the host halo density or smaller and the co-rotating dark matter fraction near the Sun, defined as particles moving with a rotational velocity lag less than 50 km s -1 , is enhanced by about 30% or less compared to a standard halo model. Such a dark disk could contribute dominantly to the low energy (of order keV for a dark matter particle with mass 100 GeV) nuclear recoil event rate of direct detection experiments, but it will not change the likelihood of detection significantly. These dark disks provide testable predictions of weakly interacting massive particle dark matter models and should be considered in detailed comparisons to experimental data. Our findings suggest that the dark disk of the Milky Way may provide a detectable signal for indirect detection experiments, contributing up to about 25% of the dark matter self-annihilation signal in the direction of the center of the Galaxy, lending the signal a noticeably oblate morphology.

  16. A PRIMER ON UNIFYING DEBRIS DISK MORPHOLOGIES

    International Nuclear Information System (INIS)

    Lee, Eve J.; Chiang, Eugene

    2016-01-01

    A “minimum model” for debris disks consists of a narrow ring of parent bodies, secularly forced by a single planet on a possibly eccentric orbit, colliding to produce dust grains that are perturbed by stellar radiation pressure. We demonstrate how this minimum model can reproduce a wide variety of disk morphologies imaged in scattered starlight. Five broad categories of disk shape can be captured: “rings,” “needles,” “ships-and-wakes,” “bars,” and “moths (a.k.a. fans),” depending on the viewing geometry. Moths can also sport “double wings.” We explain the origin of morphological features from first principles, exploring the dependence on planet eccentricity, disk inclination dispersion, and the parent body orbital phases at which dust grains are born. A key determinant in disk appearance is the degree to which dust grain orbits are apsidally aligned. Our study of a simple steady-state (secularly relaxed) disk should serve as a reference for more detailed models tailored to individual systems. We use the intuition gained from our guidebook of disk morphologies to interpret, informally, the images of a number of real-world debris disks. These interpretations suggest that the farthest reaches of planetary systems are perturbed by eccentric planets, possibly just a few Earth masses each.

  17. A Primer on Unifying Debris Disk Morphologies

    Science.gov (United States)

    Lee, Eve J.; Chiang, Eugene

    2016-08-01

    A “minimum model” for debris disks consists of a narrow ring of parent bodies, secularly forced by a single planet on a possibly eccentric orbit, colliding to produce dust grains that are perturbed by stellar radiation pressure. We demonstrate how this minimum model can reproduce a wide variety of disk morphologies imaged in scattered starlight. Five broad categories of disk shape can be captured: “rings,” “needles,” “ships-and-wakes,” “bars,” and “moths (a.k.a. fans),” depending on the viewing geometry. Moths can also sport “double wings.” We explain the origin of morphological features from first principles, exploring the dependence on planet eccentricity, disk inclination dispersion, and the parent body orbital phases at which dust grains are born. A key determinant in disk appearance is the degree to which dust grain orbits are apsidally aligned. Our study of a simple steady-state (secularly relaxed) disk should serve as a reference for more detailed models tailored to individual systems. We use the intuition gained from our guidebook of disk morphologies to interpret, informally, the images of a number of real-world debris disks. These interpretations suggest that the farthest reaches of planetary systems are perturbed by eccentric planets, possibly just a few Earth masses each.

  18. A PRIMER ON UNIFYING DEBRIS DISK MORPHOLOGIES

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eve J.; Chiang, Eugene, E-mail: evelee@berkeley.edu, E-mail: echiang@astro.berkeley.edu [Department of Astronomy, University of California Berkeley, Berkeley, CA 94720-3411 (United States)

    2016-08-20

    A “minimum model” for debris disks consists of a narrow ring of parent bodies, secularly forced by a single planet on a possibly eccentric orbit, colliding to produce dust grains that are perturbed by stellar radiation pressure. We demonstrate how this minimum model can reproduce a wide variety of disk morphologies imaged in scattered starlight. Five broad categories of disk shape can be captured: “rings,” “needles,” “ships-and-wakes,” “bars,” and “moths (a.k.a. fans),” depending on the viewing geometry. Moths can also sport “double wings.” We explain the origin of morphological features from first principles, exploring the dependence on planet eccentricity, disk inclination dispersion, and the parent body orbital phases at which dust grains are born. A key determinant in disk appearance is the degree to which dust grain orbits are apsidally aligned. Our study of a simple steady-state (secularly relaxed) disk should serve as a reference for more detailed models tailored to individual systems. We use the intuition gained from our guidebook of disk morphologies to interpret, informally, the images of a number of real-world debris disks. These interpretations suggest that the farthest reaches of planetary systems are perturbed by eccentric planets, possibly just a few Earth masses each.

  19. DISK IMAGING SURVEY OF CHEMISTRY WITH SMA. II. SOUTHERN SKY PROTOPLANETARY DISK DATA AND FULL SAMPLE STATISTICS

    International Nuclear Information System (INIS)

    Oeberg, Karin I.; Qi Chunhua; Andrews, Sean M.; Espaillat, Catherine; Wilner, David J.; Fogel, Jeffrey K. J.; Bergin, Edwin A.; Pascucci, Ilaria; Kastner, Joel H.

    2011-01-01

    This is the second in a series of papers based on data from DISCS, a Submillimeter Array observing program aimed at spatially and spectrally resolving the chemical composition of 12 protoplanetary disks. We present data on six Southern sky sources-IM Lup, SAO 206462 (HD 135344b), HD 142527, AS 209, AS 205, and V4046 Sgr-which complement the six sources in the Taurus star-forming region reported previously. CO 2-1 and HCO + 3-2 emission are detected and resolved in all disks and show velocity patterns consistent with Keplerian rotation. Where detected, the emission from DCO + 3-2, N 2 H + 3-2, H 2 CO 3 03 - 2 02 and 4 14 - 3 13 , HCN 3-2, and CN 2 33/4/2 - 1 22/3/1 are also generally spatially resolved. The detection rates are highest toward the M and K stars, while the F star SAO 206462 has only weak CN and HCN emission, and H 2 CO alone is detected toward HD 142527. These findings together with the statistics from the previous Taurus disks support the hypothesis that high detection rates of many small molecules depend on the presence of a cold and protected disk midplane, which is less common around F and A stars compared to M and K stars. Disk-averaged variations in the proposed radiation tracer CN/HCN are found to be small, despite a two orders of magnitude range of spectral types and accretion rates. In contrast, the resolved images suggest that the CN/HCN emission ratio varies with disk radius in at least two of the systems. There are no clear observational differences in the disk chemistry between the classical/full T Tauri disks and transitional disks. Furthermore, the observed line emission does not depend on the measured accretion luminosities or the number of infrared lines detected, which suggests that the chemistry outside of 100 AU is not coupled to the physical processes that drive the chemistry in the innermost few AU.

  20. Chemistry in protoplanetary disks

    Science.gov (United States)

    Semenov, D. A.

    2012-01-01

    In this lecture I discuss recent progress in the understanding of the chemical evolution of protoplanetary disks that resemble our Solar system during the first ten million years. At the verge of planet formation, strong variations of temperature, density, and radiation intensities in these disks lead to a layered chemical structure. In hot, dilute and heavily irradiated atmosphere only simple radicals, atoms, and atomic ions can survive, formed and destroyed by gas-phase processes. Beneath the atmosphere a partly UV-shielded, warm molecular layer is located, where high-energy radiation drives rich chemistry, both in the gas phase and on dust surfaces. In a cold, dense, dark disk midplane many molecules are frozen out, forming thick icy mantles where surface chemistry is active and where complex (organic) species are synthesized.

  1. 8-inch IBM floppy disk

    CERN Multimedia

    1971-01-01

    The 8-inch floppy disk was a magnetic storage disk for the data introduced commercially by IBM in 1971. It was designed by an IBM team as an inexpensive way to load data into the IBM System / 370. Plus it was a read-only bare disk containing 80 KB of data. The first read-write version was introduced in 1972 by Memorex and could contain 175 KB on 50 tracks (with 8 sectors per track). Other improvements have led to various coatings and increased capacities. Finally, it was surpassed by the mini diskette of 5.25 inches introduced in 1976.

  2. Disk tides and accretion runaway

    Science.gov (United States)

    Ward, William R.; Hahn, Joseph M.

    1995-01-01

    It is suggested that tidal interaction of an accreting planetary embryo with the gaseous preplanetary disk may provide a mechanism to breach the so-called runaway limit during the formation of the giant planet cores. The disk tidal torque converts a would-be shepherding object into a 'predator,' which can continue to cannibalize the planetesimal disk. This is more likely to occur in the giant planet region than in the terrestrial zone, providing a natural cause for Jupiter to predate the inner planets and form within the O(10(exp 7) yr) lifetime of the nebula.

  3. On Fallback Disks around Young Neutron Stars

    Science.gov (United States)

    Alpar, M. Ali; Ertan, Ü.; Erkut, M. H.

    2006-08-01

    Some bound matter in the form of a fallback disk may be an initial parameter of isolated neutron stars at birth, which, along with the initial rotation rate and dipole (and higher multipole) magnetic moments, determines the evolution of neutron stars and the categories into which they fall. This talk reviews the possibilities of fallback disk models in explaining properties of isolated neutron stars of different categories. Recent observations of a fallback disk and observational limits on fallback disks will also be discussed.

  4. New Insights into the Nature of Transition Disks from a Complete Disk Survey of the Lupus Star-forming Region

    Science.gov (United States)

    van der Marel, Nienke; Williams, Jonathan P.; Ansdell, M.; Manara, Carlo F.; Miotello, Anna; Tazzari, Marco; Testi, Leonardo; Hogerheijde, Michiel; Bruderer, Simon; van Terwisga, Sierk E.; van Dishoeck, Ewine F.

    2018-02-01

    Transition disks with large dust cavities around young stars are promising targets for studying planet formation. Previous studies have revealed the presence of gas cavities inside the dust cavities, hinting at recently formed, giant planets. However, many of these studies are biased toward the brightest disks in the nearby star-forming regions, and it is not possible to derive reliable statistics that can be compared with exoplanet populations. We present the analysis of 11 transition disks with large cavities (≥20 au radius) from a complete disk survey of the Lupus star-forming region, using ALMA Band 7 observations at 0.″3 (22–30 au radius) resolution of the 345 GHz continuum, 13CO and C18O 3–2 observations, and the spectral energy distribution of each source. Gas and dust surface density profiles are derived using the physical–chemical modeling code DALI. This is the first study of transition disks of large cavities within a complete disk survey within a star-forming region. The dust cavity sizes range from 20 to 90 au radius, and in three cases, a gas cavity is resolved as well. The deep drops in gas density and large dust cavity sizes are consistent with clearing by giant planets. The fraction of transition disks with large cavities in Lupus is ≳ 11 % , which is inconsistent with exoplanet population studies of giant planets at wide orbits. Furthermore, we present a hypothesis of an evolutionary path for large massive disks evolving into transition disks with large cavities.

  5. Herniated disk disease

    International Nuclear Information System (INIS)

    Ross, J.S.; Masaryk, T.J.; Modic, M.T.; Bohlman, H.; Wilber, G.; Carter, J.

    1988-01-01

    Thirty patients with symptoms of disk herniation and no previous surgery were examined with Gd-DTPA-enhanced MR imaging. Studies obtained before and after administration of Gd-DTPA included the following sequences: sagittal and axial spin echo (SE) 500/17 (repetition time, msec/echo time, msec), sagittal SE 2,000/60, sagittal FLASH 200/13/60. Studies were interpreted separately for presence of extradural disease (EDD) characterized by morphology, mass effect, and enhancement. Post Gd-DTPA diagnoses were: normal, n = 1; herniation, n = 28; neoplasm, n = 1. Tissue diagnosis was obtained in 13. The Gd-DTPA examination correctly changed the diagnosis in one case, provided increased confidence in the diagnosis in four, and was equivalent to the precontrast study in eight. Increased conspicuity of EDD with Gd-DTPA was related to the enhancement of epidural space analogous to IV CT and enhancement of scar surrounding disk herniation. Histologically, this scar was identical to that seen in postoperative spines, Gd-DTPA appears to be a useful adjunct in cervical and thoracic degenerative disk disease

  6. Zodiac II: Debris Disk Science from a Balloon

    Science.gov (United States)

    Bryden, Geoffrey; Traub, Wesley; Roberts, Lewis C., Jr.; Bruno, Robin; Unwin, Stephen; Backovsky, Stan; Brugarolas, Paul; Chakrabarti, Supriya; Chen, Pin; Hillenbrand, Lynne; hide

    2011-01-01

    Zodiac II is a proposed balloon-borne science investigation of debris disks around nearby stars. Debris disks are analogs of the Asteroid Belt (mainly rocky) and Kuiper Belt (mainly icy) in our Solar System. Zodiac II will measure the size, shape, brightness, and color of a statistically significant sample of disks. These measurements will enable us to probe these fundamental questions: what do debris disks tell us about the evolution of planetary systems; how are debris disks produced; how are debris disks shaped by planets; what materials are debris disks made of; how much dust do debris disks make as they grind down; and how long do debris disks live? In addition, Zodiac II will observe hot, young exoplanets as targets of opportunity. The Zodiac II instrument is a 1.1-m diameter SiC (Silicone carbide) telescope and an imaging coronagraph on a gondola carried by a stratospheric balloon. Its data product is a set of images of each targeted debris disk in four broad visible-wavelength bands. Zodiac II will address its science questions by taking high-resolution, multi-wavelength images of the debris disks around tens of nearby stars. Mid-latitude flights are considered: overnight test flights in the US followed by half-global flights in the Southern Hemisphere. These longer flights are required to fully explore the set of known debris disks accessible only to Zodiac II. On these targets, it will be 100 times more sensitive than the Hubble Space Telescope's Advanced Camera for Surveys (HST/ACS); no existing telescope can match the Zodiac II contrast and resolution performance. A second objective of Zodiac II is to use the near-space environment to raise the Technology Readiness Level (TRL) of SiC mirrors, internal coronagraphs, deformable mirrors, and wavefront sensing and control, all potentially needed for a future space-based telescope for high-contrast exoplanet imaging.

  7. Degenerative disorders of the spine

    International Nuclear Information System (INIS)

    Gallucci, Massimo; Puglielli, Edoardo; Splendiani, Alessandra; Pistoia, Francesca; Spacca, Giorgio

    2005-01-01

    Patients with back pain and degenerative disorders of the spine have a significant impact on health care costs. Some authors estimate that up to 80% of all adults experience back pain at some point in their lives. Disk herniation represents one of the most frequent causes. Nevertheless, other degenerative diseases have to be considered. In this paper, pathology and imaging of degenerative spine diseases will be discussed, starting from pathophysiology of normal age-related changes of the intervertebral disk and vertebral body. (orig.)

  8. Degenerative disorders of the spine

    Energy Technology Data Exchange (ETDEWEB)

    Gallucci, Massimo; Puglielli, Edoardo; Splendiani, Alessandra [University of L' Aquila, Department of Radiology, L' Aquila (Italy); Pistoia, Francesca; Spacca, Giorgio [S. Salvatore Hospital, Department of Neuroscience, L' Aquila (Italy)

    2005-03-01

    Patients with back pain and degenerative disorders of the spine have a significant impact on health care costs. Some authors estimate that up to 80% of all adults experience back pain at some point in their lives. Disk herniation represents one of the most frequent causes. Nevertheless, other degenerative diseases have to be considered. In this paper, pathology and imaging of degenerative spine diseases will be discussed, starting from pathophysiology of normal age-related changes of the intervertebral disk and vertebral body. (orig.)

  9. From circumstellar disks to planetary systems: observation and modeling of protoplanetary disks

    OpenAIRE

    Macías Quevedo, Enrique

    2016-01-01

    The existence of exoplanetary systems was first predicted after the discovery of accretion disks around young stars. Nowadays, with nearly 3500 exoplanets discovered, and almost 5000 more candidates identified by the Kepler space mission, planetary systems are now known to be ubiquitous around low-mass stars. The formation of these systems takes place during the stellar formation itself, from the dust and gas orbiting around the star in the protoplanetary disks. However, the process that lead...

  10. Melting of polydisperse hard disks

    NARCIS (Netherlands)

    Pronk, S.; Frenkel, D.

    2004-01-01

    The melting of a polydisperse hard-disk system is investigated by Monte Carlo simulations in the semigrand canonical ensemble. This is done in the context of possible continuous melting by a dislocation-unbinding mechanism, as an extension of the two-dimensional hard-disk melting problem. We find

  11. RADIALLY MAGNETIZED PROTOPLANETARY DISK: VERTICAL PROFILE

    International Nuclear Information System (INIS)

    Russo, Matthew; Thompson, Christopher

    2015-01-01

    This paper studies the response of a thin accretion disk to an external radial magnetic field. Our focus is on protoplanetary disks (PPDs), which are exposed during their later evolution to an intense, magnetized wind from the central star. A radial magnetic field is mixed into a thin surface layer, wound up by the disk shear, and pushed downward by a combination of turbulent mixing and ambipolar and ohmic drift. The toroidal field reaches much greater strengths than the seed vertical field that is usually invoked in PPD models, even becoming superthermal. Linear stability analysis indicates that the disk experiences the magnetorotational instability (MRI) at a higher magnetization than a vertically magnetized disk when both the effects of ambipolar and Hall drift are taken into account. Steady vertical profiles of density and magnetic field are obtained at several radii between 0.06 and 1 AU in response to a wind magnetic field B r ∼ (10 −4 –10 −2 )(r/ AU) −2 G. Careful attention is given to the radial and vertical ionization structure resulting from irradiation by stellar X-rays. The disk is more strongly magnetized closer to the star, where it can support a higher rate of mass transfer. As a result, the inner ∼1 AU of a PPD is found to evolve toward lower surface density. Mass transfer rates around 10 −8 M ⊙ yr −1 are obtained under conservative assumptions about the MRI-generated stress. The evolution of the disk and the implications for planet migration are investigated in the accompanying paper

  12. The age of the galactic disk

    International Nuclear Information System (INIS)

    Sandage, A.

    1988-07-01

    The galactic disk is a dissipative structure and must, therefore be younger than the halo if galaxy formation generally proceeds by collapse. Just how much younger the oldest stars in the galactic disk are than the oldest halo stars remains an open question. A fast collapse (on a time scale no longer than the rotation period of the extended protogalaxy) permits an age gap of the order of approximately 10 to the 9th power years. A slow collapse, governed by the cooling rate of the partially pressure supported falling gas that formed into what is now the thick stellar disk, permits a longer age gap, claimed by some to be as long as 6 Gyr. Early methods of age dating the oldest components of the disk contain implicit assumptions concerning the details of the age-metallicity relation for stars in the solar neighborhood. The discovery that this relation for open clusters outside the solar circle is different that in the solar neighborhood (Geisler 1987), complicates the earlier arguments. The oldest stars in the galactic disk are at least as old as NGC 188. The new data by Janes on NGC 6791, shown first at this conference, suggest a disk age of at least 12.5 Gyr, as do data near the main sequence termination point of metal rich, high proper motion stars of low orbital eccentricity. Hence, a case can still be made that the oldest part of the galactic thick disk is similar in age to the halo globular clusters, if their ages are the same as 47 Tuc

  13. Latest advances in high brightness disk lasers

    Science.gov (United States)

    Kuhn, Vincent; Gottwald, Tina; Stolzenburg, Christian; Schad, Sven-Silvius; Killi, Alexander; Ryba, Tracey

    2015-02-01

    In the last decade diode pumped solid state lasers have become an important tool for many industrial materials processing applications. They combine ease of operation with efficiency, robustness and low cost. This paper will give insight in latest progress in disk laser technology ranging from kW-class CW-Lasers over frequency converted lasers to ultra-short pulsed lasers. The disk laser enables high beam quality at high average power and at high peak power at the same time. The power from a single disk was scaled from 1 kW around the year 2000 up to more than 10 kW nowadays. Recently was demonstrated more than 4 kW of average power from a single disk close to fundamental mode beam quality (M²=1.38). Coupling of multiple disks in a common resonator results in even higher power. As an example we show 20 kW extracted from two disks of a common resonator. The disk also reduces optical nonlinearities making it ideally suited for short and ultrashort pulsed lasers. In a joint project between TRUMPF and IFSW Stuttgart more than 1.3 kW of average power at ps pulse duration and exceptionally good beam quality was recently demonstrated. The extremely low saturated gain makes the disk laser ideal for internal frequency conversion. We show >1 kW average power and >6 kW peak power in multi ms pulsed regime from an internally frequency doubled disk laser emitting at 515 nm (green). Also external frequency conversion can be done efficiently with ns pulses. >500 W of average UV power was demonstrated.

  14. Qualitative and quantitative assessment of degeneration of cervical intervertebral discs and facet joints.

    Science.gov (United States)

    Walraevens, Joris; Liu, Baoge; Meersschaert, Joke; Demaerel, Philippe; Delye, Hans; Depreitere, Bart; Vander Sloten, Jos; Goffin, Jan

    2009-03-01

    Degeneration of intervertebral discs and facet joints is one of the most frequently encountered spinal disorders. In order to describe and quantify degeneration and evaluate a possible relationship between degeneration and biomechanical parameters, e.g., the intervertebral range of motion and intradiscal pressure, a scoring system for degeneration is mandatory. However, few scoring systems for the assessment of degeneration of the cervical spine exist. Therefore, two separate objective scoring systems to qualitatively and quantitatively assess the degree of cervical intervertebral disc and facet joint degeneration were developed and validated. The scoring system for cervical disc degeneration consists of three variables which are individually scored on neutral lateral radiographs: "height loss" (0-4 points), "anterior osteophytes" (0-3 points) and "endplate sclerosis" (0-2 points). The scoring system for facet joint degeneration consists of four variables which are individually scored on neutral computed tomography scans: "hypertrophy" (0-2 points), "osteophytes" (0-1 point), "irregularity" on the articular surface (0-1 point) and "joint space narrowing" (0-1 point). Each variable contributes with varying importance to the overall degeneration score (max 9 points for the scoring system of cervical disc degeneration and max 5 points for facet joint degeneration). Degeneration of 20 discs and facet joints of 20 patients was blindly assessed by four raters: two neurosurgeons (one senior and one junior) and two radiologists (one senior and one junior), firstly based on first subjective impression and secondly using the scoring systems. Measurement errors and inter- and intra-rater agreement were determined. The measurement error of the scoring system for cervical disc degeneration was 11.1 versus 17.9% of the subjective impression results. This scoring system showed excellent intra-rater agreement (ICC = 0.86, 0.75-0.93) and excellent inter-rater agreement (ICC = 0

  15. NASA Lunar and Meteorite Sample Disk Program

    Science.gov (United States)

    Foxworth, Suzanne

    2017-01-01

    The Lunar and Meteorite Sample Disk Program is designed for K-12 classroom educators who work in K-12 schools, museums, libraries, or planetariums. Educators have to be certified to borrow the Lunar and Meteorite Sample Disks by attending a NASA Certification Workshop provided by a NASA Authorized Sample Disk Certifier.

  16. Regenerative and immunogenic characteristics of cultured nucleus pulposus cells from human cervical intervertebral discs.

    Directory of Open Access Journals (Sweden)

    Stefan Stich

    Full Text Available Cell-based regenerative approaches have been suggested as primary or adjuvant procedures for the treatment of degenerated intervertebral disc (IVD diseases. Our aim was to evaluate the regenerative and immunogenic properties of mildly and severely degenerated cervical nucleus pulposus (NP cells with regard to cell isolation, proliferation and differentiation, as well as to cell surface markers and co-cultures with autologous or allogeneic peripheral blood mononuclear cells (PBMC including changes in their immunogenic properties after 3-dimensional (3D-culture. Tissue from the NP compartment of 10 patients with mild or severe grades of IVD degeneration was collected. Cells were isolated, expanded with and without basic fibroblast growth factor and cultured in 3D fibrin/poly (lactic-co-glycolic acid transplants for 21 days. Real-time reverse-transcription polymerase chain reaction (RT-PCR showed the expression of characteristic NP markers ACAN, COL1A1 and COL2A1 in 2D- and 3D-culture with degeneration- and culture-dependent differences. In a 5,6-carboxyfluorescein diacetate N-succinimidyl ester-based proliferation assay, NP cells in monolayer, regardless of their grade of degeneration, did not provoke a significant proliferation response in T cells, natural killer (NK cells or B cells, not only with donor PBMC, but also with allogeneic PBMC. In conjunction with low inflammatory cytokine expression, analyzed by Cytometric Bead Array and fluorescence-activated cell sorting (FACS, a low immunogenicity can be assumed, facilitating possible therapeutic approaches. In 3D-culture, however, we found elevated immune cell proliferation levels, and there was a general trend to higher responses for NP cells from severely degenerated IVD tissue. This emphasizes the importance of considering the specific immunological alterations when including biomaterials in a therapeutic concept. The overall expression of Fas receptor, found on cultured NP cells, could have

  17. Intervertebral disc disease in dogs - Part 2: Comparison of clinical, magnetic resonance imaging, and histological findings in 74 surgically treated dogs

    NARCIS (Netherlands)

    Kranenburg, H.C.; Grinwis, G.C.M.; Bergknut, N.; Gahrmann, Ninke; Voorhout, G.; Hazewinkel, H.A.W.

    The relationship between intervertebral disc (IVD) disease and IVD degeneration remains unclear. The aim of the present study was to compare the clinical severity of IVD herniation (IVDH), determined with a neurological grading system, with findings of magnetic resonance imaging (MRI) and

  18. Debris disks as signposts of terrestrial planet formation. II. Dependence of exoplanet architectures on giant planet and disk properties

    Science.gov (United States)

    Raymond, S. N.; Armitage, P. J.; Moro-Martín, A.; Booth, M.; Wyatt, M. C.; Armstrong, J. C.; Mandell, A. M.; Selsis, F.; West, A. A.

    2012-05-01

    We present models for the formation of terrestrial planets, and the collisional evolution of debris disks, in planetary systems that contain multiple marginally unstable gas giants. We previously showed that in such systems, the dynamics of the giant planets introduces a correlation between the presence of terrestrial planets and cold dust, i.e., debris disks, which is particularly pronounced at λ ~ 70 μm. Here we present new simulations that show that this connection is qualitatively robust to a range of parameters: the mass distribution of the giant planets, the width and mass distribution of the outer planetesimal disk, and the presence of gas in the disk when the giant planets become unstable. We discuss how variations in these parameters affect the evolution. We find that systems with equal-mass giant planets undergo the most violent instabilities, and that these destroy both terrestrial planets and the outer planetesimal disks that produce debris disks. In contrast, systems with low-mass giant planets efficiently produce both terrestrial planets and debris disks. A large fraction of systems with low-mass (M ≲ 30 M⊕) outermost giant planets have final planetary separations that, scaled to the planets' masses, are as large or larger than the Saturn-Uranus and Uranus-Neptune separations in the solar system. We find that the gaps between these planets are not only dynamically stable to test particles, but are frequently populated by planetesimals. The possibility of planetesimal belts between outer giant planets should be taken into account when interpreting debris disk SEDs. In addition, the presence of ~ Earth-mass "seeds" in outer planetesimal disks causes the disks to radially spread to colder temperatures, and leads to a slow depletion of the outer planetesimal disk from the inside out. We argue that this may explain the very low frequency of >1 Gyr-old solar-type stars with observed 24 μm excesses. Our simulations do not sample the full range of

  19. THE VLA NASCENT DISK AND MULTIPLICITY SURVEY: FIRST LOOK AT RESOLVED CANDIDATE DISKS AROUND CLASS 0 AND I PROTOSTARS IN THE PERSEUS MOLECULAR CLOUD

    Energy Technology Data Exchange (ETDEWEB)

    Segura-Cox, Dominique M.; Harris, Robert J.; Looney, Leslie W. [Department of Astronomy, University of Illinois, Urbana, IL 61801 (United States); Tobin, John J. [Leiden Observatory, Leiden University, P.O. Box 9513, 2000-RA Leiden (Netherlands); Li, Zhi-Yun [Department of Astronomy, University of Virginia, Charlottesville, VA 22903 (United States); Chandler, Claire; Perez, Laura [National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Kratter, Kaitlin [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Dunham, Michael M. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Sadavoy, Sarah [Max-Planck-Institut für Astronomie, D-69117 Heidelberg (Germany); Melis, Carl, E-mail: segurac2@illinois.edu [Center for Astrophysics and Space Sciences, University of California, San Diego, CA 92093 (United States)

    2016-02-01

    We present the first dust emission results toward a sample of seven protostellar disk candidates around Class 0 and I sources in the Perseus molecular cloud from the VLA Nascent Disk and Multiplicity (VANDAM) survey with ∼0.″05 or 12 AU resolution. To examine the surface brightness profiles of these sources, we fit the Ka-band 8 mm dust-continuum data in the u, v-plane to a simple, parametrized model based on the Shakura–Sunyaev disk model. The candidate disks are well-fit by a model with a disk-shaped profile and have masses consistent with known Class 0 and I disks. The inner-disk surface densities of the VANDAM candidate disks have shallower density profiles compared to disks around more evolved Class II systems. The best-fit model radii of the seven early-result candidate disks are R{sub c} > 10 AU; at 8 mm, the radii reflect lower limits on the disk size since dust continuum emission is tied to grain size and large grains radially drift inwards. These relatively large disks, if confirmed kinematically, are inconsistent with theoretical models where the disk size is limited by strong magnetic braking to <10 AU at early times.

  20. Developmental changes in the adhesive disk during Giardia differentiation.

    Science.gov (United States)

    Palm, Daniel; Weiland, Malin; McArthur, Andrew G; Winiecka-Krusnell, Jadwiga; Cipriano, Michael J; Birkeland, Shanda R; Pacocha, Sarah E; Davids, Barbara; Gillin, Frances; Linder, Ewert; Svärd, Staffan

    2005-06-01

    Giardia lamblia is a protozoan parasite infecting the upper mammalian small intestine. Infection relies upon the ability of the parasite to attach to the intestine via a unique cytoskeletal organelle, the ventral disk. We determined the composition and structure of the disk throughout the life cycle of the parasite and identified a new disk protein, SALP-1. SALP-1 is an immunodominant protein related to striated fiber-assemblin (SFA). The disk is disassembled during encystation and stored as four fragments in the immobile cyst. Serial Analysis of Gene Expression (SAGE) showed that the mRNA levels of the disk proteins decreased in encystation but two-dimensional protein gels showed that the protein levels were more constant. The parasite emerges without a functional disk but the four disk fragments are quickly reassembled into two new disks on the dividing, early excysting form. Thus, disk proteins are stored within the cyst, ready to be used in the rapid steps of excystation.

  1. Anti-inflammatory Chitosan/Poly-γ-glutamic acid nanoparticles control inflammation while remodeling extracellular matrix in degenerated intervertebral disc.

    Science.gov (United States)

    Teixeira, Graciosa Q; Leite Pereira, Catarina; Castro, Flávia; Ferreira, Joana R; Gomez-Lazaro, Maria; Aguiar, Paulo; Barbosa, Mário A; Neidlinger-Wilke, Cornelia; Goncalves, Raquel M

    2016-09-15

    Intervertebral disc (IVD) degeneration is one of the most common causes of low back pain (LBP), the leading disorder in terms of years lived with disability. Inflammation can play a role in LPB, while impairs IVD regeneration. In spite of this, different inflammatory targets have been purposed in the context of IVD regeneration. Anti-inflammatory nanoparticles (NPs) of Chitosan and Poly-(γ-glutamic acid) with a non-steroidal anti-inflammatory drug, diclofenac (Df), were previously shown to counteract a pro-inflammatory response of human macrophages. Here, the effect of intradiscal injection of Df-NPs in degenerated IVD was evaluated. For that, Df-NPs were injected in a bovine IVD organ culture in pro-inflammatory/degenerative conditions, upon stimulation with needle-puncture and interleukin (IL)-1β. Df-NPs were internalized by IVD cells, down-regulating IL-6, IL-8, MMP1 and MMP3, and decreasing PGE2 production, compared with IL-1β-stimulated IVD punches. Interestingly, at the same time, Df-NPs promoted an up-regulation of extracellular matrix (ECM) proteins, namely collagen type II and aggrecan. Allover, this study suggests that IVD treatment with Df-NPs not only reduces inflammation, but also delays and/or decreases ECM degradation, opening perspectives to new intradiscal therapies for IVD degeneration, based on the modulation of inflammation. Degeneration of the IVD is an age-related progressive process considered to be the major cause of spine disorders. The pro-inflammatory environment and biomechanics of the degenerated IVD is a challenge for regenerative therapies. The novelty of this work is the intradiscal injection of an anti-inflammatory therapy based on Chitosan (Ch)/Poly-(γ-glutamic acid) (γ-PGA) nanoparticles (NPs) with an anti-inflammatory drug (diclofenac, Df), previously developed by us. This drug delivery system was tested in a pro-inflammatory/degenerative intervertebral disc ex vivo model. The main findings support the success of an anti

  2. The AMBRE project: The thick thin disk and thin thick disk of the Milky Way

    Science.gov (United States)

    Hayden, M. R.; Recio-Blanco, A.; de Laverny, P.; Mikolaitis, S.; Worley, C. C.

    2017-11-01

    We analyze 494 main sequence turnoff and subgiant stars from the AMBRE:HARPS survey. These stars have accurate astrometric information from Gaia DR1, providing reliable age estimates with relative uncertainties of ±1 or 2 Gyr and allowing precise orbital determinations. The sample is split based on chemistry into a low-[Mg/Fe] sequence, which are often identified as thin disk stellar populations, and high-[Mg/Fe] sequence, which are often associated with thick disk stellar populations. We find that the high-[Mg/Fe] chemical sequence has extended star formation for several Gyr and is coeval with the oldest stars of the low-[Mg/Fe] chemical sequence: both the low- and high-[Mg/Fe] sequences were forming stars at the same time. We find that the high-[Mg/Fe] stellar populations are only vertically extended for the oldest, most-metal poor and highest [Mg/Fe] stars. When comparing vertical velocity dispersion for the low- and high-[Mg/Fe] sequences, the high-[Mg/Fe] sequence has lower vertical velocity dispersion than the low-[Mg/Fe] sequence for stars of similar age. This means that identifying either group as thin or thick disk based on chemistry is misleading. The stars belonging to the high-[Mg/Fe] sequence have perigalacticons that originate in the inner disk, while the perigalacticons of stars on the low-[Mg/Fe] sequence are generally around the solar neighborhood. From the orbital properties of the stars, the high-[Mg/Fe] and low-[Mg/Fe] sequences are most likely a reflection of the chemical enrichment history of the inner and outer disk populations, respectively; radial mixing causes both populations to be observed in situ at the solar position. Based on these results, we emphasize that it is important to be clear in defining what populations are being referenced when using the terms thin and thick disk, and that ideally the term thick disk should be reserved for purely geometric definitions to avoid confusion and be consistent with definitions in external

  3. [Research advances of three-dimension printing technology in vertebrae and intervertebral disc tissue engineering].

    Science.gov (United States)

    Yang, Zechuan; Li, Chunde; Sun, Haolin

    2016-03-01

    Three-dimensional (3D) printing technology is characterized by "inside-out" stack manufacturing. Compared with conventional technologies, 3D printing has the advantage of personalization and precision. Therefore, the shape and internal structure of the scaffolds made by 3D printing technology are highly biomimetic. Besides, 3D bioprinting can precisely deposit the biomaterials, seeding cells and cytokines at the same time, which is a breakthrough in printing technique and material science. With the development of 3D printing, it will make great contributions to the reconstruction of vertebrae and intervertebral disc in the future.

  4. The Evolution of Spiral Disks

    Science.gov (United States)

    Bershady, Matthew A.; Andersen, David R.

    We report on aspects of an observational study to probe the mass assembly of large galaxy disks. In this contribution we focus on a new survey of integral-field Hα velocity-maps of nearby, face on disks. Preliminary results yield disk asymmetry amplitudes consistent with estimates based on the scatter in the local Tully-Fisher relation. We also show how the high quality of integral-field echelle spectroscopy enables determinations of kinematic inclinations to i ~20 °. This holds the promise that nearly-face-on galaxies can be included in the Tully-Fisher relation. Finally, we discuss the prospects for measuring dynamical asymmetries of distant galaxies.

  5. The CDF Run II disk inventory manager

    International Nuclear Information System (INIS)

    Hubbard, Paul; Lammel, Stephan

    2001-01-01

    The Collider Detector at Fermilab (CDF) experiment records and analyses proton-antiproton interactions at a center-of-mass energy of 2 TeV. Run II of the Fermilab Tevatron started in April of this year. The duration of the run is expected to be over two years. One of the main data handling strategies of CDF for Run II is to hide all tape access from the user and to facilitate sharing of data and thus disk space. A disk inventory manager was designed and developed over the past years to keep track of the data on disk, to coordinate user access to the data, and to stage data back from tape to disk as needed. The CDF Run II disk inventory manager consists of a server process, a user and administrator command line interfaces, and a library with the routines of the client API. Data are managed in filesets which are groups of one or more files. The system keeps track of user access to the filesets and attempts to keep frequently accessed data on disk. Data that are not on disk are automatically staged back from tape as needed. For CDF the main staging method is based on the mt-tools package as tapes are written according to the ANSI standard

  6. Effect of Capsaicin Cream on Chronic Low Back Pain in Patients With Inter-Vertebral Disc Herniation

    OpenAIRE

    Fayazi; Farokhpyam; Talali

    2015-01-01

    Background Low back pain is one of the most common debilitating disorders worldwide and the third cause of visiting a physician. One of the most common causes of low back pain is spinal disc herniation. Still there is no general agreement on the most effective treatment for it. Objectives This study aimed to determine the effect of Capsaicin cream on low back pain in patients with inter-vertebral disc herniation in Ahvaz. ...

  7. The Stability of Galaxy Disks

    NARCIS (Netherlands)

    Westfall, K. B.; Andersen, D. R.; Bershady, M. A.; Martinsson, T. P. K.; Swaters, R. A.; Verheijen, M. A. W.; Seigar, M.S.; Treuthardt, P.

    2014-01-01

    We calculate the stellar surface mass density (Σ*) and two-component (gas+stars) disk stability (QRW) for 25 late-type galaxies from the DiskMass Survey. These calculations are based on fits of a dynamical model to our ionized-gas and stellar kinematic data performed using a Markov Chain Monte Carlo

  8. Hydraulic jumps in ''viscous'' accretion disks

    International Nuclear Information System (INIS)

    Michel, F.C.

    1984-01-01

    We propose that the dissipative process necessary for rapid accretion disk evolution is driven by hydraulic jump waves on the surface of the disk. These waves are excited by the asymmetric nature of the central rotator (e.g., neutron star magnetosphere) and spiral out into the disk to form a pattern corotating with the central object. Disk matter in turn is slowed slightly at each encounter with the jump and spirals inward. In this process, the disk is heated by true turbulence produced in the jumps. Additional effects, such as a systematic misalignment of the magnetic moment of the neutron star until it is nearly orthogonal, and systematic distortion of the magnetosphere in such a way as to form an even more asymmetric central ''paddle wheel'' may enhance the interaction with inflowing matter. The application to X-ray sources corresponds to the ''slow'' solutions of Ghosh and Lamb, and therefore to rms magnetic fields of about 4 x 10 10 gauss. Analogous phenomena have been proposed to act in the formation of galactic spiral structure

  9. Chemical Evolution of a Protoplanetary Disk

    Science.gov (United States)

    Semenov, Dmitry A.

    2011-12-01

    In this paper we review recent progress in our understanding of the chemical evolution of protoplanetary disks. Current observational constraints and theoretical modeling on the chemical composition of gas and dust in these systems are presented. Strong variations of temperature, density, high-energy radiation intensities in these disks, both radially and vertically, result in a peculiar disk chemical structure, where a variety of processes are active. In hot, dilute and heavily irradiated atmosphere only the most photostable simple radicals and atoms and atomic ions exist, formed by gas-phase processes. Beneath the atmosphere a partly UV-shielded, warm molecular layer is located, where high-energy radiation drives rich ion-molecule and radical-radical chemistry, both in the gas phase and on dust surfaces. In a cold, dense, dark disk midplane many molecules are frozen out, forming thick icy mantles where surface chemistry is active and where complex polyatomic (organic) species are synthesized. Dynamical processes affect disk chemical composition by enriching it in abundances of complex species produced via slow surface processes, which will become detectable with ALMA.

  10. Quantifying the effect of intervertebral cartilage on neutral posture in the necks of sauropod dinosaurs

    OpenAIRE

    Taylor, Michael P.

    2014-01-01

    Attempts to reconstruct the neutral neck posture of sauropod dinosaurs, or indeed any tetrapod, are doomed to failure when based only on the geometry of the bony cervical vertebrae. The thickness of the articular cartilage between the centra of adjacent vertebrae affects posture. It extends (raises) the neck by an amount roughly proportional to the thickness of the cartilage. It is possible to quantify the angle of extension at an intervertebral joint: it is roughly equal, in radians, to the ...

  11. Disk Evolution and the Fate of Water

    Science.gov (United States)

    Hartmann, Lee; Ciesla, Fred; Gressel, Oliver; Alexander, Richard

    2017-10-01

    We review the general theoretical concepts and observational constraints on the distribution and evolution of water vapor and ice in protoplanetary disks, with a focus on the Solar System. Water is expected to freeze out at distances greater than 1-3 AU from solar-type central stars; more precise estimates are difficult to obtain due to uncertainties in the complex processes involved in disk evolution, including dust growth, settling, and radial drift, and the level of turbulence and viscous dissipation within disks. Interferometric observations are now providing constraints on the positions of CO snow lines, but extrapolation to the unresolved regions where water ice sublimates will require much better theoretical understanding of mass and angular momentum transport in disks as well as more refined comparison of observations with sophisticated disk models.

  12. A Pulsar and a Disk

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    Recent, unusual X-ray observations from our galactic neighbor, the Small Magellanic Cloud, have led to an interesting model for SXP 214, a pulsar in a binary star system.Artists illustration of the magnetic field lines of a pulsar, a highly magnetized, rotating neutron star. [NASA]An Intriguing BinaryAn X-ray pulsar is a magnetized, rotating neutron star in a binary system with a stellar companion. Material is fed from the companion onto the neutron star, channeled by the objects magnetic fields onto a hotspot thats millions of degrees. This hotspot rotating past our line of sight is what produces the pulsations that we observe from X-ray pulsars.Located in the Small Magellanic Cloud, SXP 214 is a transient X-ray pulsar in a binary with a Be-type star. This star is spinning so quickly that material is thrown off of it to form a circumstellar disk.Recently, a team of authors led by JaeSub Hong (Harvard-Smithsonian Center for Astrophysics) have presented new Chandra X-ray observations of SXP 214, tracking it for 50 ks (~14 hours) in January 2013. These observations reveal some very unexpected behavior for this pulsar.X-ray PuzzleThe energy distribution of the X-ray emission from SXP 214 over time. Dark shades or blue colors indicate high counts, and light shades or yellow colors indicate low counts. Lower-energy X-ray emission appeared only later, after about 20 ks. [Hong et al. 2016]Three interesting pieces of information came from the Chandra observations:SXP 214s rotation period was measured to be 211.5 s an increase in the spin rate since the discovery measurement of a 214-second period. Pulsars usually spin down as they lose angular momentum over time so what caused this one to spin up?Its overall X-ray luminosity steadily increased over the 50 ks of observations.Its spectrum became gradually softer (lower energy) over time; in the first 20 ks, the spectrum only consisted of hard X-ray photons above 3 keV, but after 20 ks, softer X-ray photons below 2 ke

  13. DEEP MIPS OBSERVATIONS OF THE IC 348 NEBULA: CONSTRAINTS ON THE EVOLUTIONARY STATE OF ANEMIC CIRCUMSTELLAR DISKS AND THE PRIMORDIAL-TO-DEBRIS DISK TRANSITION

    International Nuclear Information System (INIS)

    Currie, Thayne; Kenyon, Scott J.

    2009-01-01

    We describe new, deep MIPS photometry and new high signal-to-noise optical spectroscopy of the 2.5 Myr old IC 348 Nebula. To probe the properties of the IC 348 disk population, we combine these data with previous optical/infrared photometry and spectroscopy to identify stars with gas accretion, to examine their mid-IR colors, and to model their spectral energy distributions. IC 348 contains many sources in different evolutionary states, including protostars and stars surrounded by primordial disks, two kinds of transitional disks, and debris disks. Most disks surrounding early/intermediate spectral-type stars (>1.4 M sun at 2.5 Myr) are debris disks; most disks surrounding solar and subsolar-mass stars are primordial disks. At the 1-2 σ level, more massive stars also have a smaller frequency of gas accretion and smaller mid-IR luminosities than lower-mass stars. These trends are suggestive of a stellar mass-dependent evolution of disks, where most disks around high/intermediate-mass stars shed their primordial disks on rapid, 2.5 Myr timescales. The frequency of MIPS-detected transitional disks is ∼15%-35% for stars plausibly more massive than 0.5 M sun . The relative frequency of transitional disks in IC 348 compared to that for 1 Myr old Taurus and 5 Myr old NGC 2362 is consistent with a transition timescale that is a significant fraction of the total primordial disk lifetime.

  14. The morphometric analysis of the intervertebral foramen and the spinal nerve root in the cervical spine

    International Nuclear Information System (INIS)

    Yoshida, Yasuo

    2008-01-01

    The purpose of this study was to clarify the onset of cervical myelopathy and cervical spondylotic radiculopathy as well as what influence the anatomy of the cervical spine and cervical nerves have on their onset and occurrence of various types of disease state. We conducted imaging and morphological measurements on specimens of cervical spine of Japanese people, focusing attention on the running of intervertebral foramen and dorsal nerve rootlets of the cervical spine. The subjects were cervical spine specimens from 12 cadavers (7 males and 5 females, age at the time of death ranged from 48 to 93 years with a mean of 71 years) obtained at Showa University School of Dentistry in 2005 and 2006. Specimens were prepared by removing the atlas through the 1st thoracic vertebra from the cadavers, then resecting the soft tissue such as muscles to expose the cervical spine in whole circumference. The removed cervical spine specimens, from 1st to 7th cervical spines, were imaged by volume scan of radiographic helical CT at 0.6 mm spatial resolution, and their images were stored as Digital Imaging and Communications in Medicine (DICOM) data. Image measurement on the vertebral body, vertebral foramen, and intervertebral foramen was conducted based on DICOM data. Furthermore, macroscopic observation and measurement were conducted on the dorsal nerve rootlets of cervical spine specimens. The image measurement of cervical spine specimens showed that the intervertebral foramen at C5/6 was the narrowest, followed by C3/4, C4/5, C6/7, and C2/3, respecting. With regard to angles in the frontal section and horizontal section of the groove for the spinal nerve, there was no significant difference in the angle between the right and the left. In the frontal section, the angle was about 63deg at C3, about 57deg at C4, about 52deg at C5, and about 55deg at C6, showing a significantly acute angle at C5, while in the horizontal section, it was about 54deg at C3, about 59deg at C4, about 63

  15. LUNAR ACCRETION FROM A ROCHE-INTERIOR FLUID DISK

    Energy Technology Data Exchange (ETDEWEB)

    Salmon, Julien; Canup, Robin M., E-mail: julien@boulder.swri.edu, E-mail: robin@boulder.swri.edu [Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States)

    2012-11-20

    We use a hybrid numerical approach to simulate the formation of the Moon from an impact-generated disk, consisting of a fluid model for the disk inside the Roche limit and an N-body code to describe accretion outside the Roche limit. As the inner disk spreads due to a thermally regulated viscosity, material is delivered across the Roche limit and accretes into moonlets that are added to the N-body simulation. Contrary to an accretion timescale of a few months obtained with prior pure N-body codes, here the final stage of the Moon's growth is controlled by the slow spreading of the inner disk, resulting in a total lunar accretion timescale of {approx}10{sup 2} years. It has been proposed that the inner disk may compositionally equilibrate with the Earth through diffusive mixing, which offers a potential explanation for the identical oxygen isotope compositions of the Earth and Moon. However, the mass fraction of the final Moon that is derived from the inner disk is limited by resonant torques between the disk and exterior growing moons. For initial disks containing <2.5 lunar masses (M{sub Last-Quarter-Moon }), we find that a final Moon with mass > 0.8 M{sub Last-Quarter-Moon} contains {<=}60% material derived from the inner disk, with this material preferentially delivered to the Moon at the end of its accretion.

  16. Stratified Simulations of Collisionless Accretion Disks

    Energy Technology Data Exchange (ETDEWEB)

    Hirabayashi, Kota; Hoshino, Masahiro, E-mail: hirabayashi-k@eps.s.u-tokyo.ac.jp [Department of Earth and Planetary Science, The University of Tokyo, Tokyo, 113-0033 (Japan)

    2017-06-10

    This paper presents a series of stratified-shearing-box simulations of collisionless accretion disks in the recently developed framework of kinetic magnetohydrodynamics (MHD), which can handle finite non-gyrotropy of a pressure tensor. Although a fully kinetic simulation predicted a more efficient angular-momentum transport in collisionless disks than in the standard MHD regime, the enhanced transport has not been observed in past kinetic-MHD approaches to gyrotropic pressure anisotropy. For the purpose of investigating this missing link between the fully kinetic and MHD treatments, this paper explores the role of non-gyrotropic pressure and makes the first attempt to incorporate certain collisionless effects into disk-scale, stratified disk simulations. When the timescale of gyrotropization was longer than, or comparable to, the disk-rotation frequency of the orbit, we found that the finite non-gyrotropy selectively remaining in the vicinity of current sheets contributes to suppressing magnetic reconnection in the shearing-box system. This leads to increases both in the saturated amplitude of the MHD turbulence driven by magnetorotational instabilities and in the resultant efficiency of angular-momentum transport. Our results seem to favor the fast advection of magnetic fields toward the rotation axis of a central object, which is required to launch an ultra-relativistic jet from a black hole accretion system in, for example, a magnetically arrested disk state.

  17. Noise characteristics of barium ferrite particulate rigid disks

    Science.gov (United States)

    Kodama, Naoki; Inoue, Hitoshi; Spratt, Geoffrey; Uesaka, Yasutaro; Katsumoto, Masayuki

    1991-04-01

    This paper discusses the relationship between the noise characteristics and magnetic properties of longitudinal barium ferrite (Ba-F) rigid disks with different switching field distributions (SFD). The magnetomotive force dependencies of reverse dc-erase (RDC) noise are measured and compared with SFD values. Coated disks with acicular magnetic particles have dips and thin-film disks peaks in the RDC. In Ba-F disks, both cases are observed depending on the SFD values, though the depths or heights of the RDC noise are much smaller than those of coated disks with acicular particles or thin-film disks. Disks with small SFD values have peaks, and disks with large SFD values have dips. In order to find the relationship between noise properties and magnetic properties, interparticle interactions in Ba-F disks are investigated. Reverse dc remanence Id(H) and ac-demagnetized isothermal remanence Ir(H) are measured. Both are normalized by the saturation remanence. The deviation from the noninteracting system, ΔM = Id(H) - [1ΔM=Id(H)-[1- 2Ir(H)] and an interaction field factor (IFF) given by (H'r - Hr)/Hc, are derived from these remanent properties. Here, H'r is the field corresponding to 50% of the remanent magnetization, Hr is remanence coercivity. In Ba-F disks, ΔM shows positive interactions, and the peak heights of ΔM increase and IFF decrease with decreasing SFD values. Positive interactions between Ba-F particles seem to be caused by particle stacking. Therefore, particle stacking results in small SFD values and peak-type RDC noise.

  18. THE LONG-TERM EVOLUTION OF PHOTOEVAPORATING PROTOPLANETARY DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Jaehan; Hartmann, Lee [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48105 (United States); Zhu Zhaohuan [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Peyton Hall, Princeton, NJ 08544 (United States); Gammie, Charles, E-mail: jaehbae@umich.edu, E-mail: lhartm@umich.edu, E-mail: zhuzh@astro.princeton.edu, E-mail: gammie@illinois.edu [Department of Astronomy, University of Illinois Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801 (United States)

    2013-09-01

    We perform calculations of our one-dimensional, two-zone disk model to study the long-term evolution of the circumstellar disk. In particular, we adopt published photoevaporation prescriptions and examine whether the photoevaporative loss alone, coupled with a range of initial angular momenta of the protostellar cloud, can explain the observed decline of the frequency of optically thick dusty disks with increasing age. In the parameter space we explore, disks have accreting and/or non-accreting transitional phases lasting for {approx}< 20% of their lifetime, which is in reasonable agreement with observed statistics. Assuming that photoevaporation controls disk clearing, we find that the initial angular momentum distribution of clouds needs to be weighted in favor of slowly rotating protostellar cloud cores. Again, assuming inner disk dispersal by photoevaporation, we conjecture that this skewed angular momentum distribution is a result of fragmentation into binary or multiple stellar systems in rapidly rotating cores. Accreting and non-accreting transitional disks show different evolutionary paths on the M-dot-R{sub wall} plane, which possibly explains the different observed properties between the two populations. However, we further find that scaling the photoevaporation rates downward by a factor of 10 makes it difficult to clear the disks on the observed timescales, showing that the precise value of the photoevaporative loss is crucial to setting the clearing times. While our results apply only to pure photoevaporative loss (plus disk accretion), there may be implications for models in which planets clear disks preferentially at radii of the order of 10 AU.

  19. High-resolution observations of IRAS 08544-4431. Detection of a disk orbiting a post-AGB star and of a slow disk wind

    Science.gov (United States)

    Bujarrabal, V.; Castro-Carrizo, A.; Winckel, H. Van; Alcolea, J.; Contreras, C. Sánchez; Santander-García, M.; Hillen, M.

    2018-06-01

    Context. Aims: In order to study the effects of rotating disks in the post-asymptotic giant branch (post-AGB) evolution, we observe a class of binary post-AGB stars that seem to be systematically surrounded by equatorial disks and slow outflows. Although the rotating dynamics had only been well identified in three cases, the study of such structures is thought to be fundamental to the understanding of the formation of disks in various phases of the late evolution of binary stars and the ejection of planetary nebulae from evolved stars. Methods: We present ALMA maps of 12CO and 13CO J = 3-2 lines in the source IRAS 08544-4431, which belongs to the above mentioned class of objects. We analyzed the data by means of nebula models, which account for the expectedly composite source and can reproduce the data. From our modeling, we estimated the main nebula parameters, including the structure and dynamics and the density and temperature distributions. We discuss the uncertainties of the derived values and, in particular, their dependence on the distance. Results: Our observations reveal the presence of an equatorial disk in rotation; a low-velocity outflow is also found, probably formed of gas expelled from the disk. The main characteristics of our observations and modeling of IRAS 08544-4431 are similar to those of better studied objects, confirming our interpretation. The disk rotation indicates a total central mass of about 1.8 M⊙, for a distance of 1100 pc. The disk is found to be relatively extended and has a typical diameter of 4 × 1016 cm. The total nebular mass is 2 × 10-2 M⊙, of which 90% corresponds to the disk. Assuming that the outflow is due to mass loss from the disk, we derive a disk lifetime of 10 000 yr. The disk angular momentum is found to be comparable to that of the binary system at present. Assuming that the disk angular momentum was transferred from the binary system, as expected, the high values of the disk angular momentum in this and other

  20. RADIALLY MAGNETIZED PROTOPLANETARY DISK: VERTICAL PROFILE

    Energy Technology Data Exchange (ETDEWEB)

    Russo, Matthew [Department of Physics, University of Toronto, 60 St. George St., Toronto, ON M5S 1A7 (Canada); Thompson, Christopher [Canadian Institute for Theoretical Astrophysics, 60 St. George St., Toronto, ON M5S 3H8 (Canada)

    2015-11-10

    This paper studies the response of a thin accretion disk to an external radial magnetic field. Our focus is on protoplanetary disks (PPDs), which are exposed during their later evolution to an intense, magnetized wind from the central star. A radial magnetic field is mixed into a thin surface layer, wound up by the disk shear, and pushed downward by a combination of turbulent mixing and ambipolar and ohmic drift. The toroidal field reaches much greater strengths than the seed vertical field that is usually invoked in PPD models, even becoming superthermal. Linear stability analysis indicates that the disk experiences the magnetorotational instability (MRI) at a higher magnetization than a vertically magnetized disk when both the effects of ambipolar and Hall drift are taken into account. Steady vertical profiles of density and magnetic field are obtained at several radii between 0.06 and 1 AU in response to a wind magnetic field B{sub r} ∼ (10{sup −4}–10{sup −2})(r/ AU){sup −2} G. Careful attention is given to the radial and vertical ionization structure resulting from irradiation by stellar X-rays. The disk is more strongly magnetized closer to the star, where it can support a higher rate of mass transfer. As a result, the inner ∼1 AU of a PPD is found to evolve toward lower surface density. Mass transfer rates around 10{sup −8} M{sub ⊙} yr{sup −1} are obtained under conservative assumptions about the MRI-generated stress. The evolution of the disk and the implications for planet migration are investigated in the accompanying paper.

  1. Can disk be removed in a disk-and-washer structure

    International Nuclear Information System (INIS)

    Inagaki, Shigemi.

    1981-06-01

    A modified disk-and-washer structure, so to speak a coaxial coupled cavity structure, is proposed. It has not protrusions called disks at the inner surface of the cylinder. The thickness of the washer outer rim increases so much that it rather looks like a chain of accelerating cavities having slit around the outermost wall and through the slit they are coupled in a cylindrical cavity. SUPERFISH calculations show that both accelerating and coupling mode can be made confluent** in π-mode* operation and that the effective shunt impedance obtained under certain condition is 27 Mohm/m which is 10% less than that of KEK PF single cavity or scaled LASL side-coupled cavity. (author)

  2. Composite polymer: Glass edge cladding for laser disks

    Science.gov (United States)

    Powell, H.T.; Wolfe, C.A.; Campbell, J.H.; Murray, J.E.; Riley, M.O.; Lyon, R.E.; Jessop, E.S.

    1987-11-02

    Large neodymium glass laser disks for disk amplifiers such as those used in the Nova laser require an edge cladding which absorbs at 1 micrometer. This cladding prevents edge reflections from causing parasitic oscillations which would otherwise deplete the gain. Nova now utilizes volume-absorbing monolithic-glass claddings which are fused at high temperature to the disks. These perform quite well but are expensive to produce. Absorbing glass strips are adhesively bonded to the edges of polygonal disks using a bonding agent whose index of refraction matches that of both the laser and absorbing glass. Optical finishing occurs after the strips are attached. Laser disks constructed with such claddings have shown identical gain performance to the previous Nova disks and have been tested for hundreds of shots without significant degradation. 18 figs.

  3. Composite polymer-glass edge cladding for laser disks

    Science.gov (United States)

    Powell, Howard T.; Riley, Michael O.; Wolfe, Charles R.; Lyon, Richard E.; Campbell, John H.; Jessop, Edward S.; Murray, James E.

    1989-01-01

    Large neodymium glass laser disks for disk amplifiers such as those used in the Nova laser require an edge cladding which absorbs at 1 micrometer. This cladding prevents edge reflections from causing parasitic oscillations which would otherwise deplete the gain. Nova now utilizes volume-absorbing monolithic-glass claddings which are fused at high temperature to the disks. These perform quite well but are expensive to produce. Absorbing glass strips are adhesively bonded to the edges of polygonal disks using a bonding agent whose index of refraction matches that of both the laser and absorbing glass. Optical finishing occurs after the strips are attached. Laser disks constructed with such claddings have shown identical gain performance to the previous Nova disks and have been tested for hundreds of shots without significant degradation.

  4. A 29-Year-Old Harken Disk Mitral Valve

    Science.gov (United States)

    Hsi, David H.; Ryan, Gerald F.; Taft, Janice; Arnone, Thomas J.

    2003-01-01

    An 81-year-old woman was evaluated for prosthetic mitral valve function. She had received a Harken disk mitral valve 29 years earlier due to severe mitral valve disease. This particular valve prosthesis is known for premature disk edge wear and erosion. The patient's 2-dimensional Doppler echocardiogram showed the distinctive appearance of a disk mitral valve prosthesis. Color Doppler in diastole showed a unique crown appearance, with initial flow acceleration around the disk followed by convergence to laminar flow in the left ventricle. Cineradiographic imaging revealed normal valve function and minimal disk erosion. We believe this to be the longest reported follow-up of a surviving patient with a rare Harken disk valve. We present images with unique echocardiographic and cineangiographic features. (Tex Heart Inst J 2003;30:319–21) PMID:14677746

  5. PROTOPLANETARY DISK RESONANCES AND TYPE I MIGRATION

    International Nuclear Information System (INIS)

    Tsang, David

    2011-01-01

    Waves reflected by the inner edge of a protoplanetary disk are shown to significantly modify Type I migration, even allowing the trapping of planets near the inner disk edge for small planets in a range of disk parameters. This may inform the distribution of planets close to their central stars, as observed recently by the Kepler mission.

  6. Chemical constraints on the formation of the Galactic thick disk

    Directory of Open Access Journals (Sweden)

    Feltzing S.

    2012-02-01

    Full Text Available We highlight some results from our detailed abundance analysis study of 703 kinematically selected F and G dwarf stars in the solar neighbourhood. The analysis is based on spectra of high-resolution (R = 45000 to 110 000 and high signal-to-noise (S/N ≈ 150 to 300. The main findings include: (1 at a given metallicity, the thick disk abundance trends are more α-enhanced than those of the thin disk; (2 the metal-rich limit of the thick disk reaches at least solar metallicities; (3 the metal-poor limit of the thin disk is around [Fe/H] ≈−0.8; (4 the thick disk shows an age-metallicity gradient; (5 the thin disk does not show an age-metallicity gradient; (6 the most metal-rich thick disk stars at [Fe/H] ≈ 0 are significantly older than the most metal-poor thin disk stars at [Fe/H] ≈−0.7; (7 based on our elemental abundances we find that kinematical criteria produce thin and thick disk stellar samples that are biased in the sense that stars from the low-velocity tail of the thick disk are classified as thin disk stars, and stars from the high-velocity tail of the thin disk are classified as thick disk stars; (8 age criteria appears to produce thin and thick disk stellar samples with less contamination.

  7. Dust in protoplanetary disks: observations*

    Directory of Open Access Journals (Sweden)

    Waters L.B.F.M.

    2015-01-01

    Full Text Available Solid particles, usually referred to as dust, are a crucial component of interstellar matter and of planet forming disks surrounding young stars. Despite the relatively small mass fraction of ≈1% (in the solar neighborhood of our galaxy; this number may differ substantially in other galaxies that interstellar grains represent of the total mass budget of interstellar matter, dust grains play an important role in the physics and chemistry of interstellar matter. This is because of the opacity dust grains at short (optical, UV wavelengths, and the surface they provide for chemical reactions. In addition, dust grains play a pivotal role in the planet formation process: in the core accretion model of planet formation, the growth of dust grains from the microscopic size range to large, cm-sized or larger grains is the first step in planet formation. Not only the grain size distribution is affected by planet formation. Chemical and physical processes alter the structure and chemical composition of dust grains as they enter the protoplanetary disk and move closer to the forming star. Therefore, a lot can be learned about the way stars and planets are formed by observations of dust in protoplanetary disks. Ideally, one would like to measure the dust mass, the grain size distribution, grain structure (porosity, fluffiness, the chemical composition, and all of these as a function of position in the disk. Fortunately, several observational diagnostics are available to derive constrains on these quantities. In combination with rapidly increasing quality of the data (spatial and spectral resolution, a lot of progress has been made in our understanding of dust evolution in protoplanetary disks. An excellent review of dust evolution in protoplanetary disks can be found in Testi et al. (2014.

  8. Premixed direct injection disk

    Science.gov (United States)

    York, William David; Ziminsky, Willy Steve; Johnson, Thomas Edward; Lacy, Benjamin; Zuo, Baifang; Uhm, Jong Ho

    2013-04-23

    A fuel/air mixing disk for use in a fuel/air mixing combustor assembly is provided. The disk includes a first face, a second face, and at least one fuel plenum disposed therebetween. A plurality of fuel/air mixing tubes extend through the pre-mixing disk, each mixing tube including an outer tube wall extending axially along a tube axis and in fluid communication with the at least one fuel plenum. At least a portion of the plurality of fuel/air mixing tubes further includes at least one fuel injection hole have a fuel injection hole diameter extending through said outer tube wall, the fuel injection hole having an injection angle relative to the tube axis. The invention provides good fuel air mixing with low combustion generated NOx and low flow pressure loss translating to a high gas turbine efficiency, that is durable, and resistant to flame holding and flash back.

  9. Vibration of imperfect rotating disk

    Czech Academy of Sciences Publication Activity Database

    Půst, Ladislav; Pešek, Luděk

    2011-01-01

    Roč. 5, č. 2 (2011), s. 205-216 ISSN 1802-680X R&D Projects: GA ČR GA101/09/1166 Institutional research plan: CEZ:AV0Z20760514 Keywords : bladed disk * imperfect disk * travelling waves Subject RIV: BI - Acoustics http://www.kme.zcu.cz/acm/index.php/acm/article/view/86

  10. Cell-seeded polyurethane-fibrin structures – A possible system for intervertebral disc regeneration

    Directory of Open Access Journals (Sweden)

    C Mauth

    2009-10-01

    Full Text Available Nowadays, intervertebral disc (IVD degeneration is one of the principal causes of low back pain involving high expense within the health care system. The long-term goal is the development of a medical treatment modality focused on a more biological regeneration of the inner nucleus pulposus (NP. Hence, interest in the endoscopic implantation of an injectable material took center stage in the recent past. We report on the development of a novel polyurethane (PU scaffold as a mechanically stable carrier system for the reimplantation of expanded autologous IVD-derived cells (disc cells to stimulate regenerative processes and restore the chondrocyte-like tissue within the NP. Primary human disc cells were seeded into newly developed PU spheroids which were subsequently encapsulated in fibrin hydrogel. The study aims to analyze adhesion properties, proliferation capacity and phenotypic characterization of these cells. Polymerase chain reaction was carried out to detect the expression of genes specifically expressed by native IVD cells. Biochemical analyses showed an increased DNA content, and a progressive enhancement of total collagen and glycosaminoglycans (GAG was observed during cell culture. The results suggest the synthesis of an appropriate extracellular matrix as well as a stable mRNA expression of chondrogenic and/or NP specific markers. In conclusion, the data presented indicate an alternative medical approach to current treatment options of degenerated IVD tissue.

  11. PLANETESIMAL AND PROTOPLANET DYNAMICS IN A TURBULENT PROTOPLANETARY DISK: IDEAL STRATIFIED DISKS

    International Nuclear Information System (INIS)

    Yang, Chao-Chin; Mac Low, Mordecai-Mark; Menou, Kristen

    2012-01-01

    Due to the gravitational influence of density fluctuations driven by magneto-rotational instability in the gas disk, planetesimals and protoplanets undergo diffusive radial migration as well as changes in other orbital properties. The magnitude of the effect on particle orbits can have important consequences for planet formation scenarios. We use the local-shearing-box approximation to simulate an ideal, isothermal, magnetized gas disk with vertical density stratification and simultaneously evolve numerous massless particles moving under the gravitational field of the gas and the host star. We measure the evolution of the particle orbital properties, including mean radius, eccentricity, inclination, and velocity dispersion, and its dependence on the disk properties and the particle initial conditions. Although the results converge with resolution for fixed box dimensions, we find the response of the particles to the gravity of the turbulent gas correlates with the horizontal box size, up to 16 disk scale heights. This correlation indicates that caution should be exercised when interpreting local-shearing-box models involving gravitational physics of magneto-rotational turbulence. Based on heuristic arguments, nevertheless, the criterion L h /R ∼ O(1), where L h is the horizontal box size and R is the distance to the host star, is proposed to possibly circumvent this conundrum. If this criterion holds, we can still conclude that magneto-rotational turbulence seems likely to be ineffective at driving either diffusive migration or collisional erosion under most circumstances.

  12. The Vela pulsar with an active fallback disk

    Energy Technology Data Exchange (ETDEWEB)

    Özsükan, Gökçe; Ekşi, K. Yavuz [Faculty of Science and Letters, Department of Physics, İstanbul Technical University, Maslak 34469, İstanbul (Turkey); Hambaryan, Valeri; Neuhäuser, Ralph; Hohle, Markus M.; Ginski, Christian [Astrophysikalisches Institut und Universitäts-Sternwarte, Universität Jena, Schillergäßchen 2-3, 07745 Jena (Germany); Werner, Klaus, E-mail: eksi@itu.edu.tr [Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, Sand 1, D-72076 Tübingen (Germany)

    2014-11-20

    Fallback disks are expected to form around young neutron stars. The presence of these disks can be revealed by their blackbody spectrum in the infrared, optical, and UV bands. We present a re-reduction of the archival optical and infrared data of the Vela pulsar, together with the existing infrared and UV spectrum of Vela, and model their unpulsed components with the blackbody spectrum of a supernova debris disk. We invoke the quiescent disk solution of Sunyaev and Shakura for the description of the disk in the propeller stage and find the inner radius of the disk to be inside the light cylinder radius. We perform a high-resolution X-ray analysis with XMM-Newton and find a narrow absorption feature at 0.57 keV that can be interpreted as the K {sub α} line of He-like oxygen (O VII). The strength of the line indicates an element over-abundance in our line of sight exceeding the amounts that would be expected from interstellar medium. The spectral feature may originate from the pulsar wind nebula and may be partly caused by the reprocessed X-ray radiation by the fallback disk. We discuss the lower-than-three braking index of Vela as partially due to the contribution of the propeller torques. Our results suggest that the pulsar mechanism can work simultaneously with the propeller processes and that the debris disks can survive the radiation pressure for at least ∼10{sup 4} yr. As Vela is a relatively close object, and a prototypical pulsar, the presence of a disk, if confirmed, may indicate the ubiquity of debris disks around young neutron stars.

  13. Lactoferricin mediates anabolic and anti-catabolic effects in the intervertebral disc.

    Science.gov (United States)

    Kim, Jae-Sung; Ellman, Michael B; An, Howard S; Yan, Dongyao; van Wijnen, Andre J; Murphy, Gillian; Hoskin, David W; Im, Hee-Jeong

    2012-04-01

    Lactoferricin (LfcinB) antagonizes biological effects mediated by angiogenic and catabolic growth factors, in addition to pro-inflammatory cytokines and chemokines in human endothelial cells and tumor cells. However, the effect of LfcinB on intervertebral disc (IVD) cell metabolism has not yet been investigated. Using bovine nucleus pulposus (NP) cells, we analyzed the effect of LfcinB on proteoglycan (PG) accumulation, PG synthesis, and anabolic gene expression. We assessed expression of genes for matrix-degrading enzymes such as matrix metalloproteases (MMPs) and a disintegrin-like and metalloprotease with thrombospondin motifs (ADAMTS family), as well as their endogenous inhibitors, tissue inhibitor of metalloproteases (TIMPs). In order to understand the specific molecular mechanisms by which LfcinB exerts its biological effects, we investigated intracellular signaling pathways in NP cells. LfcinB increased PG accumulation mainly via PG synthesis in a dose-dependent manner. Simultaneously, LfcinB dose-dependently downregulated catabolic enzymes. LfcinB's anti-catabolic effects were further demonstrated by a dose-dependent increase in multiple TIMP family members. Our results demonstrate that ERK and/or p38 mitogen-activated protein kinase pathways are the key signaling cascades that exert the biological effects of LfcinB in NP cells, regulating transcription of aggrecan, SOX-9, TIMP-1, TIMP-2, TIMP-3, and iNOS. Our results suggest that LfcinB has anabolic and potent anti-catabolic biological effects on bovine IVD cells that may have considerable promise in the treatment of disc degeneration in the future. Copyright © 2011 Wiley Periodicals, Inc.

  14. Sinuous oscillations and steady warps of polytropic disks

    International Nuclear Information System (INIS)

    Balmforth, N.J.; Spiegel, E.A.

    1995-05-01

    In an asymptotic development of the equations governing the equilibria and linear stability of rapidly rotating polytropes we employed the slender aspect of these objects to reduce the three-dimensional partial differential equations to a somewhat simpler, ordinary integro-differential form. The earlier calculations dealt with isolated objects that were in centrifugal balance, that is the centrifugal acceleration of the configuration was balanced largely by self gravity with small contributions from the pressure gradient. Another interesting situation is that in which the polytrope rotates subject to externally imposed gravitational fields. In astrophysics, this is common in the theory of galactic dynamics because disks are unlikely to be isolated objects. The dark halos associated with disks also provide one possible explanation of the apparent warping of many galaxies. If the axis of the highly flattened disk is not aligned with that of the much less flattened halo, then the resultant torque of the halo gravity on the disk might provide a nonaxisymmetric distortion or disk warp. Motivated by these possibilities we shall here build models of polytropic disks of small but finite thickness which are subjected to prescribed, external gravitational fields. First we estimate how a symmetrical potential distorts the structure of the disk, then we examine its sinuous oscillations to confirm that they freely decay, hence suggesting that a warp must be externally forced. Finally, we consider steady warps of the disk plane when the axis of the disk does not coincide with that of the halo

  15. Vibration and flutter of mistuned bladed-disk assemblies

    Science.gov (United States)

    Kaza, K. R. V.; Kielb, R. E.

    1984-01-01

    An analytical model for investigating vibration and flutter of mistuned bladed disk assemblies is presented. This model accounts for elastic, inertial and aerodynamic coupling between bending and torsional motions of each individual blade, elastic and inertial couplings between the blades and the disk, and aerodynamic coupling among the blades. The disk was modeled as a circular plate with constant thickness and each blade was represented by a twisted, slender, straight, nonuniform, elastic beam with a symmetric cross section. The elastic axis, inertia axis, and the tension axis were taken to be noncoincident and the structural warping of the section was explicitly considered. The blade aerodynamic loading in the subsonic and supersonic flow regimes was obtained from two-dimensional unsteady, cascade theories. All the possible standing wave modes of the disk and traveling wave modes of the blades were included. The equations of motion were derived by using the energy method in conjunction with the assumed mode shapes for the disk and the blades. Continuities of displacement and slope at the blade-disk junction were maintained. The equations were solved to investigate the effects of blade-disk coupling and blade frequency mistuning on vibration and flutter. Results showed that the flexibility of practical disks such as those used for current generation turbofans did not have a significant influence on either the tuned or mistuned flutter characteristics. However, the disk flexibility may have a strong influence on some of the system frequencies and on forced response.

  16. Thin accretion disks in stationary axisymmetric wormhole spacetimes

    International Nuclear Information System (INIS)

    Harko, Tiberiu; Kovacs, Zoltan; Lobo, Francisco S. N.

    2009-01-01

    In this paper, we study the physical properties and the equilibrium thermal radiation emission characteristics of matter forming thin accretion disks in stationary axially symmetric wormhole spacetimes. The thin disk models are constructed by taking different values of the wormhole's angular velocity, and the time averaged energy flux, the disk temperature, and the emission spectra of the accretion disks are obtained. Comparing the mass accretion in a rotating wormhole geometry with the one of a Kerr black hole, we verify that the intensity of the flux emerging from the disk surface is greater for wormholes than for rotating black holes with the same geometrical mass and accretion rate. We also present the conversion efficiency of the accreting mass into radiation, and show that the rotating wormholes provide a much more efficient engine for the transformation of the accreting mass into radiation than the Kerr black holes. Therefore specific signatures appear in the electromagnetic spectrum of thin disks around rotating wormholes, thus leading to the possibility of distinguishing wormhole geometries by using astrophysical observations of the emission spectra from accretion disks.

  17. THE LONG-TERM EVOLUTION OF PHOTOEVAPORATING PROTOPLANETARY DISKS

    International Nuclear Information System (INIS)

    Bae, Jaehan; Hartmann, Lee; Zhu Zhaohuan; Gammie, Charles

    2013-01-01

    We perform calculations of our one-dimensional, two-zone disk model to study the long-term evolution of the circumstellar disk. In particular, we adopt published photoevaporation prescriptions and examine whether the photoevaporative loss alone, coupled with a range of initial angular momenta of the protostellar cloud, can explain the observed decline of the frequency of optically thick dusty disks with increasing age. In the parameter space we explore, disks have accreting and/or non-accreting transitional phases lasting for ∼ wall plane, which possibly explains the different observed properties between the two populations. However, we further find that scaling the photoevaporation rates downward by a factor of 10 makes it difficult to clear the disks on the observed timescales, showing that the precise value of the photoevaporative loss is crucial to setting the clearing times. While our results apply only to pure photoevaporative loss (plus disk accretion), there may be implications for models in which planets clear disks preferentially at radii of the order of 10 AU

  18. Probing Disk Stratification by Combining X-ray and Disk Inclination Data for Taurus-Auriga

    Science.gov (United States)

    Arraki, Kenza S.; Daly, B.; Harding, M.; McCleary, J.; Cox, A. W.; Grady, C. A.; Woodgate, B. E.; Hamaguchi, K.; Wisniewski, J. P.; Brakken-Thal, S.; Hilton, G.; Bonfield, D.; Williger, G. M.

    2010-01-01

    Photoelectric neutral Hydrogen absorption, N(H), is a probe of the gas and dust column towards the star. Kastner et al. (2005) found a correlation between N(H) and proplyd aspect ratio in the Orion nebula cluster. We extend this study to Taurus-Auriga by combining publicly available N(H) data from the XMM-Newton Extended Survey of the Taurus molecular cloud (XEST), with published disk inclination data obtained from HST coronagraphic imagery and mm interferometry. Additional inclinations were derived from jet proper motion and radial velocity data obtained from archival HST imagery and the Apache Point Observatory 3.5m telescope's Goddard Fabry-Perot and DIS long-slit spectrograph. Both N(H) and extinction have linear relations with system inclination, where the extinction has a smaller slope than the N(H) trend. Correlations with system inclination demonstrate that the bulk of both N(H) and extinction arise in the disk rather than in remnant envelopes, nearby molecular cloud material, or foreground material. The deficit in extinction compared with predictions for ISM-like gas to dust ratios is consistent with grain growth and settling toward the disk midplane and stratification in disks occurring by 2 Myr. However, the disks remain gas-rich, indicating that giant planet formation is still feasible. We gratefully acknowledge the support of the NASA Motivating Undergraduates in Science and Technology (MUST) Project and of NASA's APRA program under WBS#399131.02.06.02.32. A grant of Director's Discretionary Time funded observing time at the Apache Point Observatory.

  19. Magnetic hard disks for audio-visual use; AV yo jiki disk baitai

    Energy Technology Data Exchange (ETDEWEB)

    Tei, Y.; Sakaguchi, S.; Uwazumi, H. [Fuji Electric Co. Ltd., Tokyo (Japan)

    1999-11-10

    Computers, consumer, and communications are converging and fusing. The key device in homes in the near future will be an audiovisual hard disk drive (AV-HDD). The reason is that there is no other AV cash memory with high capacity, high speed, and a low price than the HDD. Fuji Electric has early started developing an AV magnetic hard disk, a core-functional element of the AV-HDD, to take the initiative in the market. This paper describes the state of plastic medium development, which is regarded as a next-generation strategic commodity. (author)

  20. Osmosis and viscoelasticity both contribute to time-dependent behaviour of the intervertebral disc under compressive load: A caprine in vitro study

    NARCIS (Netherlands)

    Emanuel, Kaj S.; van der Veen, Albert J.; Rustenburg, Christine M. E.; Smit, Theodoor H.; Kingma, Idsart

    2017-01-01

    The mechanical behaviour of the intervertebral disc highly depends on the content and transport of interstitial fluid. It is unknown, however, to what extent the time-dependent behaviour can be attributed to osmosis. Here we investigate the effect of both mechanical and osmotic loading on water

  1. Electroacupuncture improves microcirculation and neuronal morphology in the spinal cord of a rat model of intervertebral disc extrusion

    Directory of Open Access Journals (Sweden)

    Dai-xun Jiang

    2015-01-01

    Full Text Available Most studies on spinal cord neuronal injury have focused on spinal cord tissue histology and the expression of nerve cell damage and repair-related genes. The importance of the microcirculation is often ignored in spinal cord injury and repair research. Therefore, in this study, we established a rat model of intervertebral disc extrusion by inserting a silica gel pad into the left ventral surface of T 13 . Electroacupuncture was used to stimulate the bilateral Zusanli point (ST36 and Neiting point (ST44 for 14 days. Compared with control animals, blood flow in the first lumbar vertebra (L 1 was noticeably increased in rats given electroacupuncture. Microvessel density in the T 13 segment of the spinal cord was increased significantly as well. The number of normal neurons was higher in the ventral horn of the spinal cord. In addition, vacuolation in the white matter was lessened. No obvious glial cell proliferation was visible. Furthermore, hindlimb motor function was improved significantly. Collectively, our results suggest that electroacupuncture can improve neuronal morphology and microcirculation, and promote the recovery of neurological functions in a rat model of intervertebral disc extrusion.

  2. Lactoferricin enhances BMP7-stimulated anabolic pathways in intervertebral disc cells.

    Science.gov (United States)

    Ellman, Michael B; Kim, Jaesung; An, Howard S; Chen, Di; Kc, Ranjan; Li, Xin; Xiao, Guozhi; Yan, Dongyao; Suh, Joon; van Wjnen, Andre J; Wang, James H-C; Kim, Su-Gwan; Im, Hee-Jeong

    2013-07-25

    Bone-morphogenetic protein-7 (BMP7) is a well-known anabolic and anti-catabolic growth factor on intervertebral disc (IVD) matrix and cell homeostasis. Similarly, Lactoferricin B (LfcinB) has recently been shown to have pro-anabolic, anti-catabolic, anti-oxidative and/or anti-inflammatory effects in bovine disc cells in vitro. In this study, we investigated the potential benefits of using combined peptide therapy with LfcinB and BMP7 for intervertebral disc matrix repair and to understand cellular and signaling mechanisms controlled by these factors. We studied the effects of BMP7 and LfcinB as individual treatments and combined therapy on bovine nucleus pulposus (NP) cells by assessing proteoglycan (PG) accumulation and synthesis, and the gene expression of matrix protein aggrecan and transcription factor SOX-9. We also analyzed the role of Noggin, a BMP antagonist, in IVD tissue and examined its effect after stimulation with LfcinB. To understand the molecular mechanisms by which LfcinB synergizes with BMP7, we investigated the ERK-SP1 axis as a downstream intracellular signaling regulator involved in BMP7 and LfcinB-mediated activities. Treatment of bovine NP cells cultured in alginate with LfcinB plus BMP7 synergistically stimulates PG synthesis and accumulation in part by upregulation of aggrecan gene expression. The synergism results from LfcinB-mediated activation of Sp1 and SMAD signaling pathways by (i) phosphorylation of SMAD 1/5/8; (ii) downregulation of SMAD inhibitory factors [i.e., noggin and SMAD6 (inhibitory SMAD)]; and (iii) upregulation of SMAD4 (universal co-SMAD). These data indicate that LfcinB-suppression of Noggin may eliminate the negative feedback of BMP7, thereby maximizing biological activity of BMP7 and ultimately shifting homeostasis to a pro-anabolic state in disc cells. We propose that combination growth factor therapy using BMP7 and LfcinB may be beneficial for treatment of disc degeneration. Copyright © 2013 Elsevier B.V. All

  3. Hernia of intervertebral disk in the lumbar vertebral column

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, H.K.; Uhlenbrock, D.; Steiner, G.

    1986-02-01

    Degenerations of the spinal disc especially in the lumbar region are the most frequent degenerative diseases in orthopedics. As diagnostic proceedings to discover disc herniation myelography and computerized tomography have been proven to be very useful. Each of those methods show a high sensitivity and accuracy. Computerized tomography seems to be the first procedure because of the lac of any risk. Myelography has been reserved for the second approach, if there is any doubt in diagnosis. This paper will especially discuss advantages and disadvantages of MRI-tomography for the diagnosis of disc herniation. In MRI-tomography we have no radiation, there is no risk for the patient and we have the possibility of slices in different orientations with the sagittal orientation having priority in diagnosis of disc herniation. A more pronounced contrast in MRI relatively to the computerized tomography with nearly the same spatial resolution is an other important fact in favour for MRI. The value of MRI diagnosis of the spine depends however mainly on the use of special surface coils and on the use of high magnetic fields which provides a good signal to noise relation and which would permit us to use a thin-slice technique. The main disadvantage by now are the relative high costs.

  4. Hernia of intervertebral disk in the lumbar vertebral column

    International Nuclear Information System (INIS)

    Beyer, H.K.; Uhlenbrock, D.; Steiner, G.

    1986-01-01

    Degenerations of the spinal disc especially in the lumbar region are the most frequent degenerative diseases in orthopedics. As diagnostic proceedings to discover disc herniation myelography and computerized tomography have been proven to be very useful. Each of those methods show a high sensitivity and accuracy. Computerized tomography seems to be the first procedure because of the lac of any risk. Myelography has been reserved for the second approach, if there is any doubt in diagnosis. This paper will especially discuss advantages and disadvantages of MRI-tomography for the diagnosis of disc herniation. In MRI-tomography we have no radiation, there is no risk for the patient and we have the possibility of slices in different orientations with the sagittal orientation having priority in diagnosis of disc herniation. A more pronounced contrast in MRI relatively to the computerized tomography with nearly the same spatial resolution is an other important fact in favour for MRI. The value of MRI diagnosis of the spine depends however mainly on the use of special surface coils and on the use of high magnetic fields which provides a good signal to noise relation and which would permit us to use a thin-slice technique. The main disadvantage by now are the relative high costs. (orig.) [de

  5. Intervertebral Disk Disease in 3 Striped Skunks (Mephitis mephitis)

    NARCIS (Netherlands)

    Krauss, M.W.; Benato, L.; McDonnell, J.; Schoemaker, N.J.; Westerhof, I.; Bronson, E.; Gielen, I.; van Caelenberg, A.; Hellebuyck, T.; Meij, B.P.; de Decker, S.

    Objective To describe diagnostic findings, surgical technique, and outcome in 3 striped skunks (Mephitis mephitis) with a history of paraparesis. Study Design Case series. Animals Skunks (n = 3) with paraparesis. Methods Neurologic examination revealed upper motor neuron disease (T2–L2) in 2 skunks

  6. MR imaging of acute cervical spine injuries

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyu Hwa; Lee, Jung Hyung; Joo, Yang Goo [School of Medicine, Keimyung University, Daegu (Korea, Republic of)

    1995-01-15

    To describe magnetic resonance (MR) findings of the patients with acute cervical spinal injury and to assess the usefulness of the MR imagings. We retrospectively reviewed the MR images of 32 patients with acute cervical spinal injury. MR images were obtained with a 2.0 T superconductive MR imaging units (Spectro-20000, Gold-Star, Seoul), using spin-echo and gradient-echo technique. Most of patients were in their 3rd-4th decades and motor vehicle accident was the most frequent cause of acute cervical trauma. We assessed the MR findings with respect to the spinal cord, ligaments, paravertebral soft tissues, intervertebral disk, and bony spine. Spinal cord injury was the most common (65%), where cord swelling, edema, and/or hematoma were demonstrated most frequently at C5-6 level. Traumatic intervertebral disk herniations were the second most common (62.5%) and frequently occurred at the lower cervical levels, mostly at C5-6. Paravertebral soft tissue injury, vertebral body fracture, bone marrow edema and displacement were also well shown on MR images. MR imaging appears to be essential for the evaluation of traumatic disk herniations, spinal cord abnormalities, and injury of paravertebral soft tissue in the acute injury of the cervical spine.

  7. MR imaging of acute cervical spine injuries

    International Nuclear Information System (INIS)

    Kim, Kyu Hwa; Lee, Jung Hyung; Joo, Yang Goo

    1995-01-01

    To describe magnetic resonance (MR) findings of the patients with acute cervical spinal injury and to assess the usefulness of the MR imagings. We retrospectively reviewed the MR images of 32 patients with acute cervical spinal injury. MR images were obtained with a 2.0 T superconductive MR imaging units (Spectro-20000, Gold-Star, Seoul), using spin-echo and gradient-echo technique. Most of patients were in their 3rd-4th decades and motor vehicle accident was the most frequent cause of acute cervical trauma. We assessed the MR findings with respect to the spinal cord, ligaments, paravertebral soft tissues, intervertebral disk, and bony spine. Spinal cord injury was the most common (65%), where cord swelling, edema, and/or hematoma were demonstrated most frequently at C5-6 level. Traumatic intervertebral disk herniations were the second most common (62.5%) and frequently occurred at the lower cervical levels, mostly at C5-6. Paravertebral soft tissue injury, vertebral body fracture, bone marrow edema and displacement were also well shown on MR images. MR imaging appears to be essential for the evaluation of traumatic disk herniations, spinal cord abnormalities, and injury of paravertebral soft tissue in the acute injury of the cervical spine

  8. Accretion disks in active galactic nuclei

    International Nuclear Information System (INIS)

    Shields, G.A.

    1989-01-01

    Active galactic nuclei (AGN) have taunted astrophysicists for a quarter century. How do these objects produce huge luminosities---in some cases, far outshining our galaxy---from a region perhaps no larger than the solar system? Accretion onto supermassive black holes has been widely considered the best buy in theories of AGN. Much work has gone into accretion disk theory, searches for black holes in galactic nuclei, and observational tests. These efforts have not proved the disk model, but there is progress. Evidence for black holes in the nuclei of nearby galaxies is provided by observations of stellar velocities, and radiation from the disk's hot surface may be observed in the ultraviolet (UV) and neighboring spectral bands. In the review, the author describe some of the recent work on accretion disks in AGN, with an emphasis on points of contact between theory and observation

  9. Continuum Reverberation Mapping of AGN Accretion Disks

    Energy Technology Data Exchange (ETDEWEB)

    Fausnaugh, Michael M. [Department of Astronomy, Ohio State University, Columbus, OH (United States); MIT Kavli Institute for Astrophysics and Space Research, Cambridge, MA (United States); Peterson, Bradley M. [Department of Astronomy, Ohio State University, Columbus, OH (United States); Center for Cosmology and AstroParticle Physics, Ohio State University, Columbus, OH (United States); Space Telescope Science Institute, Baltimore, MD (United States); Starkey, David A. [SUPA Physics and Astronomy, University of St. Andrews, Scotland (United Kingdom); Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL (United States); Horne, Keith, E-mail: faus@mit.edu [SUPA Physics and Astronomy, University of St. Andrews, Scotland (United Kingdom); Collaboration: the AGN STORM Collaboration

    2017-12-05

    We show recent detections of inter-band continuum lags in three AGN (NGC 5548, NGC 2617, and MCG+08-11-011), which provide new constraints on the temperature profiles and absolute sizes of the accretion disks. We find lags larger than would be predicted for standard geometrically thin, optically thick accretion disks by factors of 2.3–3.3. For NGC 5548, the data span UV through optical/near-IR wavelengths, and we are able to discern a steeper temperature profile than the T ~ R{sup −3/4} expected for a standard thin disk. Using a physical model, we are also able to estimate the inclinations of the disks for two objects. These results are similar to those found from gravitational microlensing of strongly lensed quasars, and provide a complementary approach for investigating the accretion disk structure in local, low luminosity AGN.

  10. Hydrodynamical winds from a geometrically thin disk

    International Nuclear Information System (INIS)

    Fukue, Jun

    1989-01-01

    Hydrodynamical winds emanating from the surface of a geometrically thin disk under the gravitational field of the central object are examined. The attention is focused on the transonic nature of the flow. For a given configuration of streamlines, the flow fields are divided into three regions: the inner region where the gas near the disk plane is gravitationally bound to form a corona; the intermediate wind region where multiple critical points appear and the gas flows out from the disk passing through critical points; and the outer region where the gas is unbound to escape to infinity without passing through critical points. This behavior of disk winds is due to the shape of the gravitational potential of the central object along the streamline and due to the energy source distribution at the flow base on the disk plane where the potential in finite. (author)

  11. Free-fall dynamics of a pair of rigidly linked disks

    Science.gov (United States)

    Kim, Taehyun; Chang, Jaehyeock; Kim, Daegyoum

    2018-03-01

    We investigate experimentally the free-fall motion of a pair of identical disks rigidly connected to each other. The three-dimensional coordinates of the pair of falling disks were constructed to quantitatively describe its trajectory, and the flow structure formed by the disk pair was identified by using dye visualization. The rigidly linked disk pair exhibits a novel falling pattern that creates a helical path with a conical configuration in which the lower disk rotates in a wider radius than the upper disk with respect to a vertical axis. The helical motion occurs consistently for the range of disk separation examined in this study. The dye visualization reveals that a strong, noticeable helical vortex core is generated from the outer tip of the lower disk during the helical motion. With an increasing length ratio, which is the ratio of the disk separation to the diameter of the disks, the nutation angle and the rate of change in the precession angle that characterize the combined helical and conical kinematics decrease linearly, whereas the pitch of the helical path increases linearly. Although all disk pairs undergo this helical motion, the horizontal-drift patterns of the disk pair depend on the length ratio.

  12. On Hydromagnetic Stresses in Accretion Disk Boundary Layers

    DEFF Research Database (Denmark)

    Pessah, Martin Elias; Chan, Chi-kwan

    2012-01-01

    Detailed calculations of the physical structure of accretion disk boundary layers, and thus their inferred observational properties, rely on the assumption that angular momentum transport is opposite to the radial angular frequency gradient of the disk. The standard model for turbulent shear...... of efficient angular momentum transport in the inner disk regions. This suggests that the detailed structure of turbulent MHD accretion disk boundary layers could differ appreciably from those derived within the standard framework of turbulent shear viscosity...

  13. Sirtuin 6 prevents matrix degradation through inhibition of the NF-κB pathway in intervertebral disc degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Liang [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Hu, Jia [Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Weng, Yuxiong [Department of Hand Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Jia, Jie [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Zhang, Yukun, E-mail: zhangyukuncom@126.com [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China)

    2017-03-15

    Intervertebral disc degeneration (IDD) is marked by imbalanced metabolism of the extracellular matrix (ECM) in the nucleus pulposus (NP) of intervertebral discs. This study aimed to determine whether sirtuin 6 (SIRT6), a member of the sirtuin family of nicotinamide adenine dinucleotide-dependent deacetylases, protects the NP from ECM degradation in IDD. Our study showed that expression of SIRT6 markedly decreased during IDD progression. Overexpression of wild-type SIRT6, but not a catalytically inactive mutant, prevented IL-1β-induced NP ECM degradation. SIRT6 depletion by RNA interference in NP cells caused ECM degradation. Moreover, SIRT6 physically interacted with nuclear factor-κB (NF-κB) catalytic subunit p65, transcriptional activity of which was significantly suppressed by SIRT6 overexpression. These results suggest that SIRT6 prevented NP ECM degradation in vitro via inhibiting NF-κB-dependent transcriptional activity and that this effect depended on its deacetylase activity. - Highlights: • SIRT6 expression is decreased in degenerative nucleus pulposus (NP) tissues. • SIRT6 overexpression lowers IL-1β-induced matrix degradation of NP. • SIRT6 inhibition induces matrix degradation of NP. • SIRT6 prevents matrix degradation of NP via the NF-κB signaling pathway.

  14. Sirtuin 6 prevents matrix degradation through inhibition of the NF-κB pathway in intervertebral disc degeneration

    International Nuclear Information System (INIS)

    Kang, Liang; Hu, Jia; Weng, Yuxiong; Jia, Jie; Zhang, Yukun

    2017-01-01

    Intervertebral disc degeneration (IDD) is marked by imbalanced metabolism of the extracellular matrix (ECM) in the nucleus pulposus (NP) of intervertebral discs. This study aimed to determine whether sirtuin 6 (SIRT6), a member of the sirtuin family of nicotinamide adenine dinucleotide-dependent deacetylases, protects the NP from ECM degradation in IDD. Our study showed that expression of SIRT6 markedly decreased during IDD progression. Overexpression of wild-type SIRT6, but not a catalytically inactive mutant, prevented IL-1β-induced NP ECM degradation. SIRT6 depletion by RNA interference in NP cells caused ECM degradation. Moreover, SIRT6 physically interacted with nuclear factor-κB (NF-κB) catalytic subunit p65, transcriptional activity of which was significantly suppressed by SIRT6 overexpression. These results suggest that SIRT6 prevented NP ECM degradation in vitro via inhibiting NF-κB-dependent transcriptional activity and that this effect depended on its deacetylase activity. - Highlights: • SIRT6 expression is decreased in degenerative nucleus pulposus (NP) tissues. • SIRT6 overexpression lowers IL-1β-induced matrix degradation of NP. • SIRT6 inhibition induces matrix degradation of NP. • SIRT6 prevents matrix degradation of NP via the NF-κB signaling pathway.

  15. Estudo comparativo dos mecanorreceptores dos discos intervertebrais normais e degenerados da coluna lombar de humanos pela radiografia, ressonância magnética e estudo anatomopatológico Comparative study of normal and degenerated intervertebral discs' mechanoreceptors of human lumar spine X-ray, magnetic resonance and anatomopathologic study

    Directory of Open Access Journals (Sweden)

    Valdeci Manoel de Oliveira

    2007-01-01

    Full Text Available Os autores fizeram um estudo da coluna lombar de humanos, objetivando avaliar e determinar os diferentes tipos de fibras nervosas no disco intervertebral normal e no degenerado. Foram usadas dez colunas lombares de cadáveres com aproximadamente 48 a 72 horas de óbito. As peças foram submetidas a exames de radiografia simples e ressonância magnética. Após os exames, os discos foram classificados em normais e degenerados. Em seguida, foram dissecados, divididos em regiões anterior e posterior, incluídos em parafina e realizado estudo de imuno-histoquímica com a proteína S100. Com o auxílio de um programa de computador Image-Pro Plus (media cybernetics®, as fibras nervosas tiveram seu diâmetro medidos em micrômetros e classificadas em quatro tipos de fibras. Foram encontrados quatro tipos de fibras nervosas nas diferentes regiões discais. O número e o tipo de fibras variaram de acordo com a região e grau de degeneração do disco intervertebral. Concluíram que as fibras do tipo III são mais freqüentes na região anterior; as fibras dos tipos II e IV são mais freqüentes na região posterior, e as fibras do tipo I não apresentaram diferenças entre a região anterior e a posterior; além disso, o disco degenerado tem mais fibras nervosas que o disco normal.The authors conducted a study on human lumbar spine, aiming to assess and determine the different kinds of nervous fibers in normal and degenerated intervertebral discs. Ten cadaver’s lumbar spines with approximately 48 - 72 of death have been used. The pieces were submitted to simple X-ray and magnetic resonance tests. Subsequently to the tests, discs were divided into normal and degenerated. Then, they were dissected, divided into anterior and posterior according to the region, included in paraffin and an immunohistochemical study with S100 protein was performed. With the aid of Image-Pro Plus computer software (media cybernetics ®, nervous fibers’ diameters were

  16. Comparison of disability duration of lumbar intervertebral disc disorders among types of insurance in Korea.

    Science.gov (United States)

    Lee, Choong Ryeol; Kim, Joon Youn; Hong, Young Seoub; Lim, Hyun Sul; Lee, Yong Hwan; Lee, Jong Tae; Moon, Jai Dong; Jeong, Baek Geun

    2005-10-01

    The incidence of work-related musculoskeletal disorder including low back pain sharply increased since 2000 in Korea. The objectives of the present study are to compare disability duration of lumbar intervertebral disc displacement among types of insurances, and to obtain its appropriate duration. The medical records of all patients whose final diagnosis in discharge summary of chart was lumber specified intervertebral disc displacement (LIVD) in 6 large general hospitals in Korea were reviewed to compare the length of admission and disability among different types of insurances. The information on age, gender, the length of admission, the length of follow-up for LIVD, occupation, operation, combined musculoskeletal diseases, and type of insurance was investigated. 552 cases were selected and analyzed to calculate arithmetic mean, median, mode, and geometric mean of disability duration. There was a significant difference in the length of admission and disability among types of insurance after controlling covariates such as age and combined diseases by the analysis of covariance. The length of admission in cases of IACI and AI was much longer than that of HI, and the length of disability in cases of IACI was much longer than that of HI. Prolonged duration of admission and disability was not assumed due to combined diseases, complication or other unexplainable personal factors in cases of those with industrial accidents compensation insurance and automobile insurance. This means that proper management of evidence-based disability duration guidelines is urgently needed in Korea.

  17. Quantifying the effect of intervertebral cartilage on neutral posture in the necks of sauropod dinosaurs

    Directory of Open Access Journals (Sweden)

    Michael P. Taylor

    2014-12-01

    Full Text Available Attempts to reconstruct the neutral neck posture of sauropod dinosaurs, or indeed any tetrapod, are doomed to failure when based only on the geometry of the bony cervical vertebrae. The thickness of the articular cartilage between the centra of adjacent vertebrae affects posture. It extends (raises the neck by an amount roughly proportional to the thickness of the cartilage. It is possible to quantify the angle of extension at an intervertebral joint: it is roughly equal, in radians, to the cartilage thickness divided by the height of the zygapophyseal facets over the centre of rotation. Applying this formula to published measurements of well-known sauropod specimens suggests that if the thickness of cartilage were equal to 4.5%, 10% or 18% of centrum length, the neutral pose of the Apatosaurus louisae holotype CM 3018 would be extended by an average of 5.5, 11.8 or 21.2 degrees, respectively, at each intervertebral joint. For the Diplodocus carnegii holotype CM 84, the corresponding angles of additional extension are even greater: 8.4, 18.6 or 33.3 degrees. The cartilaginous neutral postures (CNPs calculated for 10% cartilage—the most reasonable estimate—appear outlandish. But it must be remembered that these would not have been the habitual life postures, because tetrapods habitually extend the base of their neck and flex the anterior part, yielding the distinctive S-curve most easily seen in birds.

  18. Quantifying the effect of intervertebral cartilage on neutral posture in the necks of sauropod dinosaurs.

    Science.gov (United States)

    Taylor, Michael P

    2014-01-01

    Attempts to reconstruct the neutral neck posture of sauropod dinosaurs, or indeed any tetrapod, are doomed to failure when based only on the geometry of the bony cervical vertebrae. The thickness of the articular cartilage between the centra of adjacent vertebrae affects posture. It extends (raises) the neck by an amount roughly proportional to the thickness of the cartilage. It is possible to quantify the angle of extension at an intervertebral joint: it is roughly equal, in radians, to the cartilage thickness divided by the height of the zygapophyseal facets over the centre of rotation. Applying this formula to published measurements of well-known sauropod specimens suggests that if the thickness of cartilage were equal to 4.5%, 10% or 18% of centrum length, the neutral pose of the Apatosaurus louisae holotype CM 3018 would be extended by an average of 5.5, 11.8 or 21.2 degrees, respectively, at each intervertebral joint. For the Diplodocus carnegii holotype CM 84, the corresponding angles of additional extension are even greater: 8.4, 18.6 or 33.3 degrees. The cartilaginous neutral postures (CNPs) calculated for 10% cartilage-the most reasonable estimate-appear outlandish. But it must be remembered that these would not have been the habitual life postures, because tetrapods habitually extend the base of their neck and flex the anterior part, yielding the distinctive S-curve most easily seen in birds.

  19. [Treatment of postoperative nonunion of fracture of lower limb with bone grafting by intervertebral disc endoscope].

    Science.gov (United States)

    Zhang, Jianlin; Tan, Yu'e; Ye, Jun; Han, Fangmin

    2012-02-01

    To explore the effectiveness of bone grafting by intervertebral disc endoscope for postoperative nonunion of fracture of lower limb. Between August 2004 and August 2008, 40 patients (23 males and 17 females) with postoperative nonunion of femoral and tibial fracture, aged 20-63 years (mean, 41.5 years) were treated. Nonunion of fracture occurred at 10-16 months after internal fixation. During the first operation, the internal fixation included interlocking intramedullary nailing of femoral fracture in 12 cases and plate in 16 cases, and interlocking intramedullary nailing of tibial fractures in 9 cases and plate in 3 cases. The X-ray films showed hypertrophic nonunion in 24 cases, common nonunion in 3 cases, and atrophic nonunion in 13 cases. The average operation time was 61 minutes (range, 40-80 minutes), and the blood loss was 80-130 mL (mean, 100 mL). The hospitalization time were 6-11 days (mean, 8.1 days). Incisions healed by first intention in all patients with no complication of infection or neurovascular injury. Forty patients were followed up 10-16 months (mean, 12.3 months). The X-ray films showed that all patients achieved healing of fracture after 4-10 months (mean, 6.8 months). No pain, disfunction, or internal fixation failure occurred. Bone grafting by intervertebral disc endoscope is an effective method for treating postoperative nonunion of femoral and tibial fracture.

  20. Radial Transport and Meridional Circulation in Accretion Disks

    Energy Technology Data Exchange (ETDEWEB)

    Philippov, Alexander A. [Department of Astrophysical Sciences, Princeton University, Ivy Lane, Princeton, NJ 08540 (United States); Rafikov, Roman R., E-mail: sashaph@princeton.edu [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)

    2017-03-10

    Radial transport of particles, elements and fluid driven by internal stresses in three-dimensional (3D) astrophysical accretion disks is an important phenomenon, potentially relevant for the outward dust transport in protoplanetary disks, origin of the refractory particles in comets, isotopic equilibration in the Earth–Moon system, etc. To gain better insight into these processes, we explore the dependence of meridional circulation in 3D disks with shear viscosity on their thermal stratification, and demonstrate a strong effect of the latter on the radial flow. Previous locally isothermal studies have normally found a pattern of the radial outflow near the midplane, switching to inflow higher up. Here we show, both analytically and numerically, that a flow that is inward at all altitudes is possible in disks with entropy and temperature steeply increasing with height. Such thermodynamic conditions may be typical in the optically thin, viscously heated accretion disks. Disks in which these conditions do not hold should feature radial outflow near the midplane, as long as their internal stress is provided by the shear viscosity. Our results can also be used for designing hydrodynamical disk simulations with a prescribed pattern of the meridional circulation.