WorldWideScience

Sample records for adjacent segment degeneration

  1. Repeated adjacent-segment degeneration after posterior lumbar interbody fusion.

    Science.gov (United States)

    Okuda, Shinya; Oda, Takenori; Yamasaki, Ryoji; Maeno, Takafumi; Iwasaki, Motoki

    2014-05-01

    One of the most important sequelae affecting long-term results is adjacent-segment degeneration (ASD) after posterior lumbar interbody fusion (PLIF). Although several reports have described the incidence rate, there have been no reports of repeated ASD. The purpose of this report was to describe 1 case of repeated ASD after PLIF. A 62-year-old woman with L-4 degenerative spondylolisthesis underwent PLIF at L4-5. At the second operation, L3-4 PLIF was performed for L-3 degenerative spondylolisthesis 6 years after the primary operation. At the third operation, L2-3 PLIF was performed for L-2 degenerative spondylolisthesis 1.5 years after the primary operation. Vertebral collapse of L-1 was detected 1 year after the third operation, and the collapse had progressed. At the fourth operation, 3 years after the third operation, vertebral column resection of L-1 and replacement of titanium mesh cages with pedicle screw fixation between T-4 and L-5 was performed. Although the patient's symptoms resolved after each operation, the time between surgeries shortened. The sacral slope decreased gradually although each PLIF achieved local lordosis at the fused segment.

  2. Risk factors for adjacent segment degeneration after surgical correction of degenerative lumbar scoliosis

    Directory of Open Access Journals (Sweden)

    Kee-yong Ha

    2013-01-01

    Full Text Available Background: Degenerative lumbar scoliosis surgery can lead to development of adjacent segment degeneration (ASD after lumbar or thoracolumbar fusion. Its incidence, risk factors, morbidity and correlation between radiological and clinical symptoms of ASD have no consensus. We evaluated the correlation between the occurrence of radiologic adjacent segment disease and certain imperative parameters. Materials and Methods: 98 patients who had undergone surgical correction and lumbar/thoracolumbar fusion with pedicle screw instrumentation for degenerative lumbar scoliosis with a minimum 5 year followup were included in the study. We evaluated the correlation between the occurrence of radiologic adjacent segment disease and imperative patient parameters like age at operation, sex, body mass index (BMI, medical comorbidities and bone mineral density (BMD. The radiological parameters taken into consideration were Cobb′s angle, angle type, lumbar lordosis, pelvic incidence, intercristal line, preoperative existence of an ASD on plain radiograph and magnetic resonance imaging (MRI and surgical parameters were number of the fusion level, decompression level, floating OP (interlumbar fusion excluding L5-S1 level and posterolateral lumbar interbody fusion (PLIF. Clinical outcomes were assessed with the Visual Analogue Score (VAS and Oswestry Disability Index (ODI. Results: ASD was present in 44 (44.9% patients at an average period of 48.0 months (range 6-98 months. Factors related to occurrence of ASD were preoperative existence of disc degeneration (as revealed by MRI and age at operation ( P = 0.0001, 0.0364. There were no statistically significant differences between radiological adjacent segment degeneration and clinical results (VAS, P = 0.446; ODI, P = 0.531. Conclusions: Patients over the age of 65 years and with preoperative disc degeneration (as revealed by plain radiograph and MRI were at a higher risk of developing ASD.

  3. Cystic adventitial degeneration: ectopic ganglia from adjacent joint capsules.

    Science.gov (United States)

    Ortmann, J; Widmer, M K; Gretener, S; Do, D D; Willenberg, T; Daliri, A; Baumgartner, I

    2009-11-01

    Cystic adventitial degeneration is a rare non-atherosclerotic cause of peripheral arterial occlusive disease, mainly seen in young men without other evidence of vascular disease. Diagnosis will be established by clinical findings and by ultrasound or angiography and can be treated by excision or enucleation of the affected arterial segment or by percutaneous ultrasound-guided aspiration. However, the etiology of adventitial cysts remains unknown. We report a case of cystic adventitial degeneration showing a connection between the joint capsule and the adventitial cyst, supporting the theory that cystic adventitial degeneration may represent ectopic ganglia from adjacent joint capsules.

  4. Loading effects of anterior cervical spine fusion on adjacent segments

    Directory of Open Access Journals (Sweden)

    Chien-Shiung Wang

    2012-11-01

    Full Text Available Adjacent segment degeneration typically follows anterior cervical spine fusion. However, the primary cause of adjacent segment degeneration remains unknown. Therefore, in order to identify the loading effects that cause adjacent segment degeneration, this study examined the loading effects to superior segments adjacent to fused bone following anterior cervical spine fusion. The C3–C6 cervical spine segments of 12 sheep were examined. Specimens were divided into the following groups: intact spine (group 1; and C5–C6 segments that were fused via cage-instrumented plate fixation (group 2. Specimens were cycled between 20° flexion and 15° extension with a displacement control of 1°/second. The tested parameters included the range of motion (ROM of each segment, torque and strain on both the body and inferior articular process at the superior segments (C3–C4 adjacent to the fused bone, and the position of the neutral axis of stress at under 20° flexion and 15° extension. Under flexion and Group 2, torque, ROM, and strain on both the bodies and facets of superior segments adjacent to the fused bone were higher than those of Group 1. Under extension and Group 2, ROM for the fused segment was less than that of Group 1; torque, ROM, and stress on both the bodies and facets of superior segments adjacent to the fused bone were higher than those of Group 1. These analytical results indicate that the muscles and ligaments require greater force to achieve cervical motion than the intact spine following anterior cervical spine fusion. In addition, ROM and stress on the bodies and facets of the joint segments adjacent to the fused bone were significantly increased. Under flexion, the neutral axis of the stress on the adjacent segment moved backward, and the stress on the bodies of the segments adjacent to the fused bone increased. These comparative results indicate that increased stress on the adjacent segments is caused by stress-shielding effects

  5. Adjacent segment degeneration after lumbar spinal fusion: the impact of anterior column support: a randomized clinical trial with an eight- to thirteen-year magnetic resonance imaging follow-up.

    Science.gov (United States)

    Videbaek, Tina S; Egund, Niels; Christensen, Finn B; Grethe Jurik, Anne; Bünger, Cody E

    2010-10-15

    Randomized controlled trial. To analyze long-term adjacent segment degeneration (ASD) after lumbar fusion on magnetic resonance imaging and compare randomization groups with and without anterior column support. ASD can be a long-term complication after fusion. The prevalence and the cause of ASD are not well documented, but ASD are one of the main arguments for introducing the use of motion-preserving techniques as an alternative to fusion. Anterior lumbar interbody fusion combined with posterolateral lumbar fusion (ALIF+PLF) has been proved superior to posterolateral fusion alone regarding outcome and cost-effectiveness. Between 1996 and 1999, 148 patients with severe chronic low back pain were randomly selected for ALIF+PLF or for PLF alone. Ninety-five patients participated. ASD was examined on magnetic resonance imaging with regard to disc degeneration, disc herniation, stenosis, and endplate changes. Disc heights on radiographs taken at index surgery and at long-term follow-up were compared. Outcome was assessed by validated questionnaires. The follow-up rate was 76%. ASD was similar between randomization groups. In the total cohort, endplate changes were seen in 26% of the participants and correlated significantly with the presence of disc degeneration and disc herniation. Disc degeneration and dorsal disc herniation were the parameters registered most frequently and were significantly more pronounced at the first adjacent level than at the second and the third adjacent levels. Patients without disc height reduction over time were significantly younger than patients with disc height reduction. Disc degeneration and stenosis correlated significantly with outcome at the first adjacent level. The cause of the superior outcome in the group with anterior support is still unclear. Compared with the findings reported in the literature, the prevalence of ASD is likely to be in concordance with the expected changes in a nonoperated symptomatic population and therefore

  6. A systematic review of definitions and classification systems of adjacent segment pathology.

    Science.gov (United States)

    Kraemer, Paul; Fehlings, Michael G; Hashimoto, Robin; Lee, Michael J; Anderson, Paul A; Chapman, Jens R; Raich, Annie; Norvell, Daniel C

    2012-10-15

    Systematic review. To undertake a systematic review to determine how "adjacent segment degeneration," "adjacent segment disease," or clinical pathological processes that serve as surrogates for adjacent segment pathology are classified and defined in the peer-reviewed literature. Adjacent segment degeneration and adjacent segment disease are terms referring to degenerative changes known to occur after reconstructive spine surgery, most commonly at an immediately adjacent functional spinal unit. These can include disc degeneration, instability, spinal stenosis, facet degeneration, and deformity. The true incidence and clinical impact of degenerative changes at the adjacent segment is unclear because there is lack of a universally accepted classification system that rigorously addresses clinical and radiological issues. A systematic review of the English language literature was undertaken and articles were classified using the Grades of Recommendation Assessment, Development, and Evaluation criteria. RESULTS.: Seven classification systems of spinal degeneration, including degeneration at the adjacent segment, were identified. None have been evaluated for reliability or validity specific to patients with degeneration at the adjacent segment. The ways in which terms related to adjacent segment "degeneration" or "disease" are defined in the peer-reviewed literature are highly variable. On the basis of the systematic review presented in this article, no formal classification system for either cervical or thoracolumbar adjacent segment disorders currently exists. No recommendations regarding the use of current classification of degeneration at any segments can be made based on the available literature. A new comprehensive definition for adjacent segment pathology (ASP, the now preferred terminology) has been proposed in this Focus Issue, which reflects the diverse pathology observed at functional spinal units adjacent to previous spinal reconstruction and balances

  7. Comparison of pedicle screw-based dynamic stabilization and fusion surgery in the treatment of radiographic adjacent-segment degeneration: a retrospective analysis of single L5-S1 degenerative spondylosis covering 4 years.

    Science.gov (United States)

    Han, Yu; Sun, Jianguang; Luo, Chenghan; Huang, Shilei; Li, Liren; Ji, Xiang; Duan, Xiaozong; Wang, Zhenqing; Pi, Guofu

    2016-12-01

    OBJECTIVE Pedicle screw-based dynamic spinal stabilization systems (PDSs) were devised to decrease, theoretically, the risk of long-term complications such as adjacent-segment degeneration (ASD) after lumbar fusion surgery. However, to date, there have been few studies that fully proved that a PDS can reduce the risk of ASD. The purpose of this study was to examine whether a PDS can influence the incidence of ASD and to discuss the surgical coping strategy for L5-S1 segmental spondylosis with preexisting L4-5 degeneration with no related symptoms or signs. METHODS This study retrospectively compared 62 cases of L5-S1 segmental spondylosis in patients who underwent posterior lumbar interbody fusion (n = 31) or K-Rod dynamic stabilization (n = 31) with a minimum of 4 years' follow-up. The authors measured the intervertebral heights and spinopelvic parameters on standing lateral radiographs and evaluated preexisting ASD on preoperative MR images using the modified Pfirrmann grading system. Radiographic ASD was evaluated according to the results of radiography during follow-up. RESULTS All 62 patients achieved remission of their neurological symptoms without surgical complications. The Kaplan-Meier curve and Cox proportional-hazards model showed no statistically significant differences between the 2 surgical groups in the incidence of radiographic ASD (p > 0.05). In contrast, the incidence of radiographic ASD was 8.75 times (95% CI 1.955-39.140; p = 0.005) higher in the patients with a preoperative modified Pfirrmann grade higher than 3 than it was in patients with a modified Pfirrmann grade of 3 or lower. In addition, no statistical significance was found for other risk factors such as age, sex, and spinopelvic parameters. CONCLUSIONS Pedicle screw-based dynamic spinal stabilization systems were not found to be superior to posterior lumbar interbody fusion in preventing radiographic ASD (L4-5) during the midterm follow-up. Preexisting ASD with a modified Pfirrmann

  8. Risk Factors for the Development of Adjacent Segment Disease Following Anterior Cervical Arthrodesis

    Directory of Open Access Journals (Sweden)

    Ezgi Akar

    2015-06-01

    Full Text Available Aim: The aim of this study was to clinically and radiologically evaluate the efficacy of anterior cervical discectomy and fusion (ACDF in the treatment of adjacent level degeneration. Methods: We retrospectively evaluated 89 patients (55 females, 34 males who underwent ACDF. Adjacent segment degeneration findings were evaluated by investigating new osteophyte formation, growth of existing osteophytes, ossification of the anterior longitudinal ligament, presence of intervertebral disc space narrowing, sagittal alignment and range of motion (ROM using serial radiographs and magnetic resonance imaging. Results: The mean age of the 89 patients was 41.3 (24-76 years. The mean follow-up duration was 34.3 (12-64 months. Radiographic evidence of adjacent segment degeneration was observed in 12 patients (13.4%. Nine (75% patients had new complaints. Of the patients who had degenerative changes, 7 were (58% were male, 5 (42% were female; the mean age was 46 (30- 62 years. It was observed that the level of fusion and the number of fusion did not increase the adjacent segment degeneration. All of 12 patients were observed to have a non lordotic cervical spine and increased ROM. Conclusion: Development of degeneration at the level adjacent to region anterior cervical discectomy and fusion performed is higher compared to non-adjacent levels. The level of fusion and the number of fusion levels have no effect on the development of degeneration. (The Medical Bulletin of Haseki 2015; 53:120-3

  9. Impact of body mass index on adjacent segment disease after lumbar fusion for degenerative spine disease.

    Science.gov (United States)

    Ou, Chien-Yu; Lee, Tao-Chen; Lee, Tsung-Han; Huang, Yu-Hua

    2015-04-01

    Adjacent segment disease is an important complication after fusion of degenerative lumbar spines. However, the role of body mass index (BMI) in adjacent segment disease has been addressed less. To examine the relationship between BMI and adjacent segment disease after lumbar fusion for degenerative spine diseases. For this retrospective study, we enrolled 190 patients undergoing lumbar fusion surgery for degeneration. BMI at admission was documented. Adjacent segment disease was defined by integration of the clinical presentations and radiographic criteria based on the morphology of the dural sac on magnetic resonance images. Adjacent segment disease was identified in 13 of the 190 patients, accounting for 6.8%. The interval between surgery and diagnosis as adjacent segment disease ranged from 21 to 66 months. Five of the 13 patients required subsequent surgical intervention for clinically relevant adjacent segment disease. In the logistic regression model, BMI was a risk factor for adjacent segment disease after lumbar fusion for degenerative spine diseases (odds ratio, 1.68; 95% confidence interval, 1.27-2.21; P disease rate by 67.6%. The patients were subdivided into 2 groups based on BMI, and up to 11.9% of patients with BMI ≥ 25 kg/m were diagnosed as having adjacent segment disease at the last follow-up. BMI is a risk factor for adjacent segment disease in patients undergoing lumbar fusion for degenerative spine diseases. Because BMI is clinically objective and modifiable, controlling body weight before or after surgery may provide opportunities to reduce the rate of adjacent segment disease and to improve the outcome of fusion surgery.

  10. Spondylolisthesis adjacent to a cervical disc arthroplasty does not increase the risk of adjacent level degeneration.

    Science.gov (United States)

    Kieser, David Christopher; Cawley, Derek Thomas; Roscop, Cecile; Mazas, Simon; Coudert, Pierre; Boissiere, Louis; Obeid, Ibrahim; Vital, Jean-Marc; Pointillart, Vincent; Gille, Olivier

    2018-03-31

    To understand whether a spondylolisthesis in the sub-axial spine cranial to a cervical disc arthroplasty (CDA) construes a risk of adjacent level disease (ALD). A retrospective review of 164 patients with a minimum 5-year follow-up of a cervical disc arthroplasty was performed. Multi-level surgeries, including hybrid procedures, were included. Multiple implant types were included. The two inter-vertebral discs (IVD) cranial of the CDA were monitored for evidence of radiologic degeneration using the Kettler criteria. The rate of ALD in CDA found in this series was 17.8%, with most affecting the immediately adjacent IVD (27.4 and 7.6%, respectively p = 0.000). Pre-operative mild spondylolisthesis adjacent to a planned CDA was not found to be a risk factor for ALD within 5 years. Those with a degenerative spondylolisthesis are at higher risk of ALD (33%) than those with a non-degenerative cause for their spondylolisthesis (11%). Post-operative CDA alignment, ROM or induced spondylolisthesis do not affect the rate of ALD in those with an adjacent spondylolisthesis. Patients with ALD experience significantly worse 5-year pain and functional outcomes than those unaffected by ALD. A pre-operatively identified mild spondylolisthesis in the sub-axial spine cranially adjacent to a planned CDA is not a risk factor for ALD within 5 years. These slides can be retrieved under Electronic Supplementary Material.

  11. Diffusion-Weighted MRI Assessment of Adjacent Disc Degeneration After Thoracolumbar Vertebral Fractures

    Energy Technology Data Exchange (ETDEWEB)

    Noriega, David C., E-mail: dcnoriega1970@gmail.com [Valladolid University Hospital, Spine Department (Spain); Marcia, Stefano, E-mail: stemarcia@gmail.com [SS. Trinità Hospital ASL 8 Cagliari, Department of Radiology (Italy); Ardura, Francisco, E-mail: fardura@ono.com [Valladolid University Hospital, Spine Department (Spain); Lite, Israel Sanchez, E-mail: israelslite@hotmail.com [Valladolid University Hospital, Radiology Department (Spain); Marras, Mariangela, E-mail: mariangela.marrasmd@gmail.com [Azienda Ospedaliero Brotzu (A.O.B.), Department of Radiology (Italy); Saba, Luca, E-mail: lucasaba@tiscali.it [Azienda Ospedaliero Universitaria (A.O.U.), Department of Radiology (Italy)

    2016-09-15

    ObjectiveThe purpose of this study was to assess, by the mean apparent diffusion coefficient (ADC), if a relationship exists between disc ADC and MR findings of adjacent disc degeneration after thoracolumbar fractures treated by anatomic reduction using vertebral augmentation (VAP).Materials and MethodsTwenty non-consecutive patients (mean age 50.7 years; range 45–56) treated because of vertebral fractures, were included in this study. There were 10 A3.1 and 10 A1.2 fractures (AO classification). Surgical treatment using VAP was applied in 14 cases, and conservative in 6 patients. MRI T2-weighted images and mapping of apparent diffusion coefficient (ADC) of the intervertebral disc adjacent to the fractured segment were performed after a mean follow-up of 32 months. A total of 60 discs, 3 per patient, were analysed: infra-adjacent, supra-adjacent and a control disc one level above the supra-adjacent.ResultsNo differences between patients surgically treated and those following a conservative protocol regarding the average ADC values obtained in the 20 control discs analysed were found. Considering all discs, average ADC in the supra-adjacent level was lower than in the infra-adjacent (1.35 ± 0.12 vs. 1.53 ± 0.06; p < 0.001). Average ADC values of the discs used as a control were similar to those of the infra-adjacent level (1.54 ± 0.06). Compared to surgically treated patients, discs at the supra-adjacent fracture level showed statistically significant lower values in cases treated conservatively (p < 0.001). The variation in the delay of surgery had no influence on the average values of ADC at any of the measured levels.ConclusionsADC measurements of the supra-adjacent discs after a mean follow-up of 32 months following thoracolumbar fractures, showed that restoration of the vertebral collapse by minimally invasive VAP prevents posttraumatic disc degeneration.

  12. The change of adjacent segment after cervical disc arthroplasty compared with anterior cervical discectomy and fusion: a meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Dong, Liang; Xu, Zhengwei; Chen, Xiujin; Wang, Dongqi; Li, Dichen; Liu, Tuanjing; Hao, Dingjun

    2017-10-01

    Many meta-analyses have been performed to study the efficacy of cervical disc arthroplasty (CDA) compared with anterior cervical discectomy and fusion (ACDF); however, there are few data referring to adjacent segment within these meta-analyses, or investigators are unable to arrive at the same conclusion in the few meta-analyses about adjacent segment. With the increased concerns surrounding adjacent segment degeneration (ASDeg) and adjacent segment disease (ASDis) after anterior cervical surgery, it is necessary to perform a comprehensive meta-analysis to analyze adjacent segment parameters. To perform a comprehensive meta-analysis to elaborate adjacent segment motion, degeneration, disease, and reoperation of CDA compared with ACDF. Meta-analysis of randomized controlled trials (RCTs). PubMed, Embase, and Cochrane Library were searched for RCTs comparing CDA and ACDF before May 2016. The analysis parameters included follow-up time, operative segments, adjacent segment motion, ASDeg, ASDis, and adjacent segment reoperation. The risk of bias scale was used to assess the papers. Subgroup analysis and sensitivity analysis were used to analyze the reason for high heterogeneity. Twenty-nine RCTs fulfilled the inclusion criteria. Compared with ACDF, the rate of adjacent segment reoperation in the CDA group was significantly lower (panalysis. There was no statistically significant difference in ASDeg between CDA and ACDF within the 24-month follow-up period; however, the rate of ASDeg in CDA was significantly lower than that of ACDF with the increase in follow-up time (p.05). Cervical disc arthroplasty provided a lower adjacent segment range of motion (ROM) than did ACDF, but the difference was not statistically significant. Compared with ACDF, the advantages of CDA were lower ASDeg and adjacent segment reoperation. However, there was no statistically significant difference in ASDis and adjacent segment ROM. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Adjacent segment disease and C-ADR: promises fulfilled?

    Science.gov (United States)

    Riew, K Daniel; Schenk-Kisser, Jeannette M.; Skelly, Andrea C.

    2012-01-01

    Study design: Systematic review. Clinical question: Do the rates and timing of adjacent segment disease (ASD) differ between cervical total disc arthroplasty (C-ADR) and anterior cervical discectomy and fusion (ACDF) in patients treated for cervical degenerative disc disease? Methods: A systematic search of MEDLINE/PubMed and bibliographies of key articles was done to identify studies with long-term follow-up for symptomatic and/or radiographic ASD comparing C-ADR with fusion for degenerative disc disease of the cervical spine. The focus was on studies with longer follow-up (48–60 months) of primary US Food and Drug Administration trials of Prestige ST, Prodisc-C, and Bryan devices as available. Trials of other discs with a minimum of 24 months follow-up were considered for inclusion. Studies evaluating lordosis/angle changes at adjacent segments and case series were excluded. Results: From 14 citations identified, four reports from three randomized controlled trials and four nonrandomized studies are summarized. Risk differences between C-ADR and ACF for symptomatic ASD were 1.5%–2.3% and were not significant across RCT reports. Time to development of ASD did not significantly differ between treatments. Rates of radiographic ASD were variable. No meaningful comparison of ASD rates based on disc design was possible. No statistical differences in adjacent segment range of motion were noted between treatment groups. Conclusion: Our analysis reveals that, to date, there is no evidence that arthroplasty decreases ASD compared with ACDF; the promise of arthroplasty decreasing ASD has not been fulfilled. PMID:23236312

  14. Adjacent segment disease in degenerative pathologies with posterior instrumentation

    Directory of Open Access Journals (Sweden)

    Ana Guadalupe Ramírez Olvera

    2015-03-01

    Full Text Available OBJECTIVE: To establish the real incidence of adjacent segment disease after fusion, and to identify the levels and predisposing factors for the pathology, as well as the functional results. METHODS: a retrospective case series study with level of evidence IIB, in a sample of 179 patients diagnosed with stenosis of the lumbar spine, spondylolisthesis and degenerative scoliosis, submitted to surgery in the period 2005 to December 2013, with posterior instrumentation and posterolateral fusion, with follow-up from 2007 until May 2014, in which the symptomology and radiographic findings were evaluated, to establish the diagnosis and treatment. RESULTS: the study included 179 patients diagnosed with stenosis of the lumbar spine (n=116, isthmic and degenerative spondylolisthesis (n=50 and degenerative scoliosis (n=13; during the study, 20 cases of adjacent level segment were identified, 80% of which were treated surgically with extension of the instrumentation, while 20% were treated conservatively with NSAIDs and therapeutic blocks. CONCLUSION: An incidence of 11% was found, with an average of 3.25 years in diagnosis and treatment, a prevalence of females and diagnosis of stenosis of the lumbar canal on posterior instrumentation, a predominance of levels L4-L5; 80% were treated with extension of the instrumentation. The complications were persistent radiculopathy, infection of the surgical wound, and one death due to causes not related to the lumbar pathology.

  15. Adjacent segment infection after surgical treatment of spondylodiscitis.

    Science.gov (United States)

    Siam, Ahmed Ezzat; El Saghir, Hesham; Boehm, Heinrich

    2016-03-01

    This is the first case series to describe adjacent segment infection (ASI) after surgical treatment of spondylodiscitis (SD). Patients with SD, spondylitis who were surgically treated between 1994 and 2012 were included. Out of 1187 cases, 23 (1.94 %) returned to our institution (Zentralklinik Bad Berka) with ASI: 10 males, 13 females, with a mean age of 65.1 years and a mean follow-up of 69 months. ASI most commonly involved L3-4 (seven patients), T12-L1 (five) and L2-3 (four). The mean interval between operations of primary infection and ASI was 36.9 months. All cases needed surgical intervention, debridement, reconstruction and fusion with longer instrumentation, with culture and sensitivity-based postoperative antimicrobial therapy. At last follow-up, six patients (26.1 %) were mobilized in a wheelchair with a varying degree of paraplegia (three had pre-existing paralysis). Three patients died within 2 months after the ASI operation (13 %). Excellent outcomes were achieved in five patients, and good in eight. Adjacent segment infection after surgical treatment of spondylodiscitis is a rare complication (1.94 %). It is associated with multimorbidity and shows a high mortality rate and a high neurological affection rate. Possible explanations are: haematomas of repeated micro-fractures around screw loosening, haematogenous spread, direct inoculation or a combination of these factors. ASI may also lead to proximal junctional kyphosis, as found in this series. We suggest early surgical intervention with anterior debridement, reconstruction and fusion with posterior instrumentation, followed by antimicrobial therapy for 12 weeks. Level IV retrospective uncontrolled case series.

  16. Methodology for the systematic reviews on an adjacent segment pathology.

    Science.gov (United States)

    Norvell, Daniel C; Dettori, Joseph R; Skelly, Andrea C; Riew, K Daniel; Chapman, Jens R; Anderson, Paul A

    2012-10-15

    A systematic review. To provide a detailed description of the methods undertaken in the systematic search and analytical summary of adjacent segment pathology (ASP) issues and to describe the process used to develop consensus statements and clinical recommendations regarding factors associated with the prevention and treatment of ASP. We present methods used in conducting the systematic, evidence-based reviews and development of expert panel consensus statements and clinical recommendations on the classification, natural history, risk factors, and treatment of radiographical and clinical ASP. Our intent is that clinicians will combine the information from these reviews with an understanding of their own capacities and experience to better manage patients at risk of ASP and consider future research for the prevention and treatment of ASP. A systematic search and critical review of the English-language literature was undertaken for articles published on the classification, risk, risk factors, and treatment of radiographical and clinical ASP. Articles were screened for relevance using a priori criteria, and relevant articles were critically reviewed. Whether an article was included for review depended on whether the study question was descriptive, one of therapy, or one of prognosis. The strength of evidence for the overall body of literature in each topic area was determined by 2 independent reviewers considering risk of bias, consistency, directness, and precision of results using a modification of the Grades of Recommendation Assessment, Development and Evaluation (GRADE) criteria. Disagreements were resolved by consensus. Findings from articles meeting inclusion criteria were summarized. From these summaries, consensus statements or clinical recommendations were formulated among subject experts through a modified Delphi process using the GRADE approach. A total of 3382 articles were identified and screened on 14 topics relating to the classification, risks, risk

  17. Adjacent-segment disease after thoracic pedicle screw fixation.

    Science.gov (United States)

    Agarwal, Nitin; Heary, Robert F; Agarwal, Prateek

    2018-03-01

    OBJECTIVE Pedicle screw fixation is a technique widely used to treat conditions ranging from spine deformity to fracture stabilization. Pedicle screws have been used traditionally in the lumbar spine; however, they are now being used with increasing frequency in the thoracic spine as a more favorable alternative to hooks, wires, or cables. Although safety concerns, such as the incidence of adjacent-segment disease (ASD) after cervical and lumbar fusions, have been reported, such issues in the thoracic spine have yet to be addressed thoroughly. Here, the authors review the literature on ASD after thoracic pedicle screw fixation and report their own experience specifically involving the use of pedicle screws in the thoracic spine. METHODS Select references from online databases, such as PubMed (provided by the US National Library of Medicine at the National Institutes of Health), were used to survey the literature concerning ASD after thoracic pedicle screw fixation. To include the authors' experience at Rutgers New Jersey Medical School, a retrospective review of a prospectively maintained database was performed to determine the incidence of complications over a 13-year period in 123 consecutive adult patients who underwent thoracic pedicle screw fixation. Children, pregnant or lactating women, and prisoners were excluded from the review. By comparing preoperative and postoperative radiographic images, the occurrence of thoracic ASD and disease within the surgical construct was determined. RESULTS Definitive radiographic fusion was detected in 115 (93.5%) patients. Seven incidences of instrumentation failure and 8 lucencies surrounding the screws were observed. One patient was observed to have ASD of the thoracic spine. The mean follow-up duration was 50 months. CONCLUSIONS This long-term radiographic evaluation revealed the use of pedicle screws for thoracic fixation to be an effective stabilization modality. In particular, ASD seems to be less of a problem in the

  18. Effect of Lumbar Lordosis on the Adjacent Segment in Transforaminal Lumbar Interbody Fusion: A Finite Element Analysis.

    Science.gov (United States)

    Zhao, Xin; Du, Lin; Xie, Youzhuan; Zhao, Jie

    2018-06-01

    We used a finite element (FE) analysis to investigate the biomechanical changes caused by transforaminal lumbar interbody fusion (TLIF) at the L4-L5 level by lumbar lordosis (LL) degree. A lumbar FE model (L1-S5) was constructed based on computed tomography scans of a 30-year-old healthy male volunteer (pelvic incidence,= 50°; LL, 52°). We investigated the influence of LL on the biomechanical behavior of the lumbar spine after TLIF in L4-L5 fusion models with 57°, 52°, 47°, and 40° LL. The LL was defined as the angle between the superior end plate of L1 and the superior end plate of S1. A 150-N vertical axial preload was imposed on the superior surface of L3. A 10-N/m moment was simultaneously applied on the L3 superior surface along the radial direction to simulate the 4 basic physiologic motions of flexion, extension, lateral bending, and torsion in the numeric simulations. The range of motion (ROM) and intradiscal pressure (IDP) of L3-L4 were evaluated and compared in the simulated cases. In all motion patterns, the ROM and IDP were both increased after TLIF. In addition, the decrease in lordosis generally increased the ROM and IDP in all motion patterns. This FE analysis indicated that decreased spinal lordosis may evoke overstress of the adjacent segment and increase the risk of the pathologic development of adjacent segment degeneration; thus, adjacent segment degeneration should be considered when planning a spinal fusion procedure. Copyright © 2018. Published by Elsevier Inc.

  19. Failure of cervical arthroplasty in a patient with adjacent segment disease associated with Klippel-Feil syndrome

    Directory of Open Access Journals (Sweden)

    Ioannis D Papanastassiou

    2011-01-01

    Full Text Available Cervical arthroplasty may be justified in patients with Klippel-Feil syndrome (KFS in order to preserve cervical motion. The aim of this paper is to report an arthroplasty failure in a patient with KFS. A 36-year-old woman with KFS underwent two-level arthroplasty for adjacent segment disc degeneration. Anterior migration of the cranial prosthesis was encountered 5 months postoperatively and was successfully revised with anterior cervical fusion. Cervical arthroplasty in an extensively stiff and fused neck is challenging and may lead to catastrophic failure. Although motion preservation is desirable in KFS, the special biomechanical features may hinder arthroplasty. Fusion or hybrid constructs may represent more reasonable options, especially when multiple fused segments are present.

  20. Cervical facet dislocation adjacent to the fused motion segment

    Directory of Open Access Journals (Sweden)

    Kunio Yokoyama

    2016-01-01

    Full Text Available This study reports on a case that forces re-examination of merits and demerits of anterior cervical fusion. A 79-year-old male was brought to the emergency room (ER of our hospital after he fell and struck the occipital region of his head following excessive alcohol consumption. Four years prior, he had undergone anterior cervical discectomy and fusion of C5/6 and a magnetic resonance imaging (MRI performed 3 years after this surgery indicated that he was suffering from degeneration of C6/7 intervertebral discs. After arriving at the ER, he presented motor impairment at level C7 and lower of manual muscle testing grade 1 as well as moderate loss of physical sensation from the trunk and peripheries of both upper limbs to the peripheries of both lower limbs (Frankel B. Cervical computed tomography (CT indicated anterior dislocation of C6/7, and MRI indicated severe spinal cord edema. We performed manipulative reduction of C6/7 with the patient under general anesthesia. Next, we performed laminectomy on C5-T1 and posterior fusion on C6/7. Postoperative CT indicated that cervical alignment had improved, and MRI indicated that the spinal cord edema observed prior to surgery had been mitigated. Three months after surgery, motor function and sensory impairment of the lower limbs had improved, and the patient was ambulatory upon discharge from the hospital (Frankel D. In the present case, although C5 and 6 were rigidly fused, degeneration of the C6/7 intervertebral disc occurred and stability was compromised. As a result, even slight trauma placed a severe dynamic burden on the facet joint of C6/7, which led to dislocation.

  1. Sacroiliac Joint Fusion Minimally Affects Adjacent Lumbar Segment Motion: A Finite Element Study.

    Science.gov (United States)

    Lindsey, Derek P; Kiapour, Ali; Yerby, Scott A; Goel, Vijay K

    2015-01-01

    Adjacent segment disease is a recognized consequence of fusion in the spinal column. Fusion of the sacroiliac joint is an effective method of pain reduction. Although effective, the consequences of sacroiliac joint fusion and the potential for adjacent segment disease for the adjacent lumbar spinal levels is unknown. The objective of this study was to quantify the change in range of motion of the sacroiliac joint and the adjacent lumbar spinal motion segments due to sacroiliac joint fusion and compare these changes to previous literature to assess the potential for adjacent segment disease in the lumbar spine. An experimentally validated finite element model of the lumbar spine and pelvis was used to simulate a fusion of the sacroiliac joint using three laterally placed triangular implants (iFuse Implant System, SI-BONE, Inc., San Jose, CA). The range of motion of the sacroiliac joint and the adjacent lumbar spinal motion segments were calculated using a hybrid loading protocol and compared with the intact range of motion in flexion, extension, lateral bending, and axial rotation. The range of motions of the treated sacroiliac joints were reduced in flexion, extension, lateral bending, and axial rotation, by 56.6%, 59.5%, 27.8%, and 53.3%, respectively when compared with the intact condition. The stiffening of the sacroiliac joint resulted in increases at the adjacent lumbar motion segment (L5-S1) for flexion, extension, lateral bending, and axial rotation, of 3.0%, 3.7%, 1.1%, and 4.6%, respectively. Fusion of the sacroiliac joint resulted in substantial (> 50%) reductions in flexion, extension, and axial rotation of the sacroiliac joint with minimal (sacroiliac joint fusion, the long-term clinical results remain to be investigated.

  2. Pelvic incidence-lumbar lordosis mismatch predisposes to adjacent segment disease after lumbar spinal fusion.

    Science.gov (United States)

    Rothenfluh, Dominique A; Mueller, Daniel A; Rothenfluh, Esin; Min, Kan

    2015-06-01

    Several risk factors and causes of adjacent segment disease have been debated; however, no quantitative relationship to spino-pelvic parameters has been established so far. A retrospective case-control study was carried out to investigate spino-pelvic alignment in patients with adjacent segment disease compared to a control group. 45 patients (ASDis) were identified that underwent revision surgery for adjacent segment disease after on average 49 months (7-125), 39 patients were selected as control group (CTRL) similar in the distribution of the matching variables, such as age, gender, preoperative degenerative changes, and numbers of segments fused with a mean follow-up of 84 months (61-142) (total n = 84). Several radiographic parameters were measured on pre- and postoperative radiographs, including lumbar lordosis measured (LL), sacral slope, pelvic incidence (PI), and tilt. Significant differences between ASDis and CTRL groups on preoperative radiographs were seen for PI (60.9 ± 10.0° vs. 51.7 ± 10.4°, p = 0.001) and LL (48.1 ± 12.5° vs. 53.8 ± 10.8°, p = 0.012). Pelvic incidence was put into relation to lumbar lordosis by calculating the difference between pelvic incidence and lumbar lordosis (∆PILL = PI-LL, ASDis 12.5 ± 16.7° vs. CTRL 3.4 ± 12.1°, p = 0.001). A cutoff value of 9.8° was determined by logistic regression and ROC analysis and patients classified into a type A (∆PILL lordosis mismatch. In type A spino-pelvic alignment, 25.5 % of patients underwent revision surgery for adjacent segment disease, whereas 78.3 % of patients classified as type B alignment had revision surgery. Classification of patients into type A and B alignments yields a sensitivity for predicting adjacent segment disease of 71 %, a specificity of 81 % and an odds ratio of 10.6. In degenerative disease of the lumbar spine a high pelvic incidence with diminished lumbar lordosis seems to predispose to adjacent segment disease. Patients with such pelvic incidence

  3. Sagittal Alignment As a Predictor of Clinical Adjacent Segment Pathology requiring Surgery after Anterior Cervical Arthrodesis

    Science.gov (United States)

    Park, Moon Soo; Kelly, Michael P.; Lee, Dong-Ho; Min, Woo-Kie; Rahman, Ra’Kerry K.; Riew, K. Daniel

    2014-01-01

    BACKGROUND CONTEXT Postoperative malalignment of the cervical spine may alter cervical spine mechanics, and put patients at risk for clinical adjacent segment pathology requiring surgery. PURPOSE To investigate whether a relationship exists between cervical spine sagittal alignment and clinical adjacent segment pathology requiring surgery (CASP-S) following anterior cervical fusion (ACF). STUDY DESIGN Retrospective matched study. PATIENT SAMPLE One hundred twenty two patients undergoing ACF from 1996 to 2008 were identified, with a minimum of 2 year follow-up. OUTCOME MEASURES Radiographs were reviewed to measure the sagittal alignment using C2 and C7 sagittal plumb lines, distance from the fusion mass plumb line to the C2 and C7 plumb lines, the alignment of the fusion mass, caudally adjacent disc angle, the sagittal slope angle of the superior endplate of the vertebra caudally adjacent to the fusion mass, T1 sagittal angle, overall cervical sagittal alignment, and curve patterns by Katsuura classification. METHODS One hundred twenty two patients undergoing ACF from 1996 to 2008 were identified, with a minimum of 1 year follow-up. Patients were divided into groups according to the development of CASP requiring surgery (Control / CASP-S) and by number/location of levels fused. Radiographs were reviewed to measure the sagittal alignment using C2 and C7 sagittal plumb lines, distance from the fusion mass plumb line to the C2 and C7 plumb lines, the alignment of the fusion mass, caudally adjacent disc angle, the sagittal slope angle of the superior endplate of the vertebra caudally adjacent to the fusion mass, T1 sagittal angle, overall cervical sagittal alignment, and curve patterns by Katsuura classification. Appropriate statistical tests were performed to calculate relationships between the variables and the development of CASP-S. No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related

  4. Adjacent segment pathology following anterior decompression and fusion using cage and plate for the treatment of degenerative cervical spinal diseases.

    Science.gov (United States)

    Song, Kyung-Jin; Choi, Byung-Wan; Kim, Jong-Kil

    2014-12-01

    Retrospective study. To analyze the incidence and prevalence of clinical adjacent segment pathology (CASP) following anterior decompression and fusion with cage and plate augmentation for degenerative cervical diseases. No long-term data on the use of cage and plate augmentation have been reported. The study population consisted of 231 patients who underwent anterior cervical discectomy and fusion (ACDF) with cage and plate for degenerative cervical spinal disease. The incidence and prevalence of CASP was determined by using the Kaplan-Meier survival analysis. To analyze the factors that influence CASP, data on preoperative and postoperative sagittal alignment, spinal canal diameter, the distance between the plate and adjacent disc, extent of fusion level, and the presence or absence of adjacent segment degenerative changes by imaging studies were evaluated. CASP occurred in 15 of the cases, of which 9 required additional surgery. At 8-year follow-up, the average yearly incidence was 1.1%. The rate of disease-free survival based on Kaplan-Meier survival analysis was 93.6% at 5 years and 90.2% at 8 years. No statistically significant differences in CASP incidence based on radiological analysis were observed. Significantly high incidence of CASP was observed in the presence of increased adjacent segment degenerative changes (pdegenerative cervical disease is associated with a lower incidence in CSAP by 1.1% per year, and the extent of preoperative adjacent segment degenerative changes has been shown as a risk factor for CASP.

  5. Correlation between cervical lordosis and adjacent segment pathology after anterior cervical spinal surgery.

    Science.gov (United States)

    Lee, Soo Eon; Jahng, Tae-Ahn; Kim, Hyun Jib

    2015-12-01

    To evaluate the incidence and risk factors for adjacent segment pathology (ASP) after anterior cervical spinal surgery. Fourteen patients (12 male, mean age 47.1 years) who underwent single-level cervical disk arthroplasty (CDA group) and 28 case-matched patients (24 male, mean age 53.6 years) who underwent single-level anterior cervical discectomy and fusion (ACDF group) were included. Presence of radiologic ASP (RASP) was based on observed changes in anterior osteophytes, disks, and calcification of the anterior longitudinal ligament on lateral radiographs. The mean follow-up period was 43.4 months in the CDA group and 44.6 months in the ACDF group. At final follow-up, ASP was observed in 5 (35.7%) CDA patients and 16 (57.1%) ACDF patients (p = 0.272). The interval between surgery and ASP development was 33.8 months in the CDA group and 16.3 months in the ACDF group (p = 0.046). The ASP risk factor analysis indicated postoperative cervical angle at C3-7 being more lordotic in non-ASP patients in both groups. Restoration of lordosis occurred in the CDA group regardless of the presence of ASP, but heterotopic ossification development was associated with the presence of ASP in the CDA group. And the CDA group had significantly greater clinical improvements than those in the ACDF group when ASP was present. In both CDA and ACDF patients, RASP developed, but CDA was associated with a delay in ASP development. A good clinical outcome was expected in CDA group, even when ASP developed. Restoration of cervical lordosis was an important factor in anterior cervical spine surgery.

  6. Automated Segmentation Methods of Drusen to Diagnose Age-Related Macular Degeneration Screening in Retinal Images

    Directory of Open Access Journals (Sweden)

    Young Jae Kim

    2018-01-01

    Full Text Available Existing drusen measurement is difficult to use in clinic because it requires a lot of time and effort for visual inspection. In order to resolve this problem, we propose an automatic drusen detection method to help clinical diagnosis of age-related macular degeneration. First, we changed the fundus image to a green channel and extracted the ROI of the macular area based on the optic disk. Next, we detected the candidate group using the difference image of the median filter within the ROI. We also segmented vessels and removed them from the image. Finally, we detected the drusen through Renyi’s entropy threshold algorithm. We performed comparisons and statistical analysis between the manual detection results and automatic detection results for 30 cases in order to verify validity. As a result, the average sensitivity was 93.37% (80.95%~100% and the average DSC was 0.73 (0.3~0.98. In addition, the value of the ICC was 0.984 (CI: 0.967~0.993, p<0.01, showing the high reliability of the proposed automatic method. We expect that the automatic drusen detection helps clinicians to improve the diagnostic performance in the detection of drusen on fundus image.

  7. Síndrome adyacente Síndrome adjacente Adjacent segment disease

    Directory of Open Access Journals (Sweden)

    Gustavo Martin

    2012-06-01

    recovered in both cases. MRI before the first intervention was 83% with Pfirmann IV. AS level: 38% L3-L4, L5-S1: 26%. AS types: lumbar stenosis worsened by monosegmental antero-listhesis in 20 and retro-listhesis in 14; multisegmental stenosis 4, disc herniation 4, crush fracture 4, stenosis without listhesis 4. Period between the 2 surgeries: on average 6 years. CONCLUSION: An incidence of 9.4% of reoperation due to adjacent syndrome makes this disease an important long-term problem, forcing the surgeon to take all the possible steps to avoid this. With the results of this retrospective study we could only say that the segments more likely to develop AS are those with Pfirmann IV on MRI and that the relation VP (20% and PS (80% pre and post-operative should be taken into account to return to the spinal column perfect mechanical condition. Prospective clinical studies are needed for more conclusive results.

  8. Loosely coupled level sets for retinal layers and drusen segmentation in subjects with dry age-related macular degeneration

    Science.gov (United States)

    Novosel, Jelena; Wang, Ziyuan; de Jong, Henk; Vermeer, Koenraad A.; van Vliet, Lucas J.

    2016-03-01

    Optical coherence tomography (OCT) is used to produce high-resolution three-dimensional images of the retina, which permit the investigation of retinal irregularities. In dry age-related macular degeneration (AMD), a chronic eye disease that causes central vision loss, disruptions such as drusen and changes in retinal layer thicknesses occur which could be used as biomarkers for disease monitoring and diagnosis. Due to the topology disrupting pathology, existing segmentation methods often fail. Here, we present a solution for the segmentation of retinal layers in dry AMD subjects by extending our previously presented loosely coupled level sets framework which operates on attenuation coefficients. In eyes affected by AMD, Bruch's membrane becomes visible only below the drusen and our segmentation framework is adapted to delineate such a partially discernible interface. Furthermore, the initialization stage, which tentatively segments five interfaces, is modified to accommodate the appearance of drusen. This stage is based on Dijkstra's algorithm and combines prior knowledge on the shape of the interface, gradient and attenuation coefficient in the newly proposed cost function. This prior knowledge is incorporated by varying the weights for horizontal, diagonal and vertical edges. Finally, quantitative evaluation of the accuracy shows a good agreement between manual and automated segmentation.

  9. Mutation mechanisms that underlie turnover of a human telomere-adjacent segmental duplication containing an unstable minisatellite.

    Science.gov (United States)

    Hills, Mark; Jeyapalan, Jennie N; Foxon, Jennifer L; Royle, Nicola J

    2007-04-01

    Subterminal regions, juxtaposed to telomeres on human chromosomes, contain a high density of segmental duplications, but relatively little is known about the evolutionary processes that underlie sequence turnover in these regions. We have characterized a segmental duplication adjacent to the Xp/Yp telomere, each copy containing a hypervariable array of the DXYS14 minisatellite. Both DXYS14 repeat arrays mutate at a high rate (0.3 and 0.2% per gamete) but linkage disequilibrium analysis across 27 SNPs and a direct crossover assay show that recombination during meiosis is suppressed. Therefore instability at DXYS14a and b is dominated by intra-allelic processes or possibly conversion limited to the repeat arrays. Furthermore some chromosomes (14%) carry only one copy of the duplicon, including one DXYS14 repeat array that is also highly mutable (1.2% per gamete). To explain these and other observations, we propose there is another low-rate mutation process that causes copy number change in part or all of the duplicon.

  10. Segmentation and quantification of retinal lesions in age-related macular degeneration using polarization-sensitive optical coherence tomography.

    Science.gov (United States)

    Baumann, Bernhard; Gotzinger, Erich; Pircher, Michael; Sattmann, Harald; Schuutze, Christopher; Schlanitz, Ferdinand; Ahlers, Christian; Schmidt-Erfurth, Ursula; Hitzenberger, Christoph K

    2010-01-01

    We present polarization-sensitive optical coherence tomography (PS-OCT) for quantitative assessment of retinal pathologies in age-related macular degeneration (AMD). On the basis of the polarization scrambling characteristics of the retinal pigment epithelium, novel segmentation algorithms were developed that allow one to segment pathologic features such as drusen and atrophic zones in dry AMD as well as to determine their dimensions. Results from measurements in the eyes of AMD patients prove the ability of PS-OCT for quantitative imaging based on the retinal features polarizing properties. Repeatability measurements were performed in retinas diagnosed with drusen and geographic atrophy in order to evaluate the performance of the described methods. PS-OCT appears as a promising imaging modality for three-dimensional retinal imaging and ranging with additional contrast based on the structures' tissue-inherent polarization properties.

  11. Assessing the effects of lumbar posterior stabilization and fusion to vertebral bone density in stabilized and adjacent segments by using Hounsfield unit

    Science.gov (United States)

    Öksüz, Erol; Deniz, Fatih Ersay; Demir, Osman

    2017-01-01

    Background Computed tomography (CT) with Hounsfield unit (HU) is being used with increasing frequency for determining bone density. Established correlations between HU and bone density have been shown in the literature. The aim of this retrospective study was to determine the bone density changes of the stabilized and adjacent segment vertebral bodies by comparing HU values before and after lumbar posterior stabilization. Methods Sixteen patients who had similar diagnosis of lumbar spondylosis and stenosis were evaluated in this study. Same surgical procedures were performed to all of the patients with L2-3-4-5 transpedicular screw fixation, fusion and L3-4 total laminectomy. Bone mineral density measurements were obtained with clinical CT. Measurements were obtained from stabilized and adjacent segment vertebral bodies. Densities of vertebral bodies were evaluated with HU before the surgeries and approximately one year after the surgeries. The preoperative HU value of each vertebra was compared with postoperative HU value of the same vertebrae by using statistical analysis. Results The HU values of vertebra in the stabilized and adjacent segments consistently decreased after the operations. There were significant differences between the preoperative HU values and the postoperative HU values of the all evaluated vertebral bodies in the stabilized and adjacent segments. Additionally first sacral vertebra HU values were found to be significantly higher than lumbar vertebra HU values in the preoperative group and postoperative group. Conclusions Decrease in the bone density of the adjacent segment vertebral bodies may be one of the major predisposing factors for adjacent segment disease (ASD). PMID:29354730

  12. 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.

  13. Relationship between screw sagittal angle and stress on endplate of adjacent segments after anterior cervical corpectomy and fusion with internal fixation: a Chinese finite element study.

    Science.gov (United States)

    Zhang, Yu; Tang, Yibo; Shen, Hongxing

    2017-12-01

    In order to reduce the incidence of adjacent segment disease (ASD), the current study was designed to establish Chinese finite element models of normal 3rd~7th cervical vertebrae (C3-C7) and anterior cervical corpectomy and fusion (ACCF) with internal fixation , and analyze the influence of screw sagittal angle (SSA) on stress on endplate of adjacent cervical segments. Mimics 8.1 and Abaqus/CAE 6.10 softwares were adopted to establish finite element models. For C4 superior endplate and C6 inferior endplate, their anterior areas had the maximum stress in anteflexion position, and their posterior areas had the maximum stress in posterior extension position. As SSA increased, the stress reduced. With an increase of 10° in SSA, the stress on anterior areas of C4 superior endplate and C6 inferior endplate reduced by 12.67% and 7.99% in anteflexion position, respectively. With an increase of 10° in SSA, the stress on posterior areas of C4 superior endplate and C6 inferior endplate reduced by 9.68% and 10.22% in posterior extension position, respectively. The current study established Chinese finite element models of normal C3-C7 and ACCF with internal fixation , and demonstrated that as SSA increased, the stress on endplate of adjacent cervical segments decreased. In clinical surgery, increased SSA is able to play important role in protecting the adjacent cervical segments and reducing the incidence of ASD.

  14. Long-segment plication technique for arteriovenous fistulae threatened by diffuse aneurysmal degeneration: short-term results.

    Science.gov (United States)

    Powell, Alexis; Wooster, Mathew; Carroll, Megan; Cardentey-Oliva, Damian; Cavanagh-Voss, Sean; Armstrong, Paul; Shames, Murray; Illig, Karl; Gabbard, Wesley

    2015-08-01

    A substantial number of patients with autologous arteriovenous fistulas (AVFs) develop diffuse aneurysmal degeneration, which frequently interferes with successful access. These AVFs are often deemed unsalvageable. We hypothesize that long-segment plication in these patients can be performed safely with acceptable short-term AVF salvage rates. We reviewed a prospectively maintained database to identify all patients with extensive AVF aneurysmal disease operated on for this problem. Thirty-five patients, 25 (71%) male and 10 (29%) female were operated on between July 2012 and January 2014. AVFs included 23 (66%) brachiocephalic, 5 (14%) radiocephalic, and 7 brachiobasilic (20%) fistulae (one first stage only but in use). The cohort had one or a combination of local pain, arm edema, cannulation issue, recurrent thrombosis, dysfunctional during dialysis, or extreme tortuousity. Time range for AVF creation to consultation ranged from 3 months to 11 years. All underwent long-segment plication over a 20-Fr Bougie with or without segmental vein resection; 3 underwent concomitant first rib resection for costoclavicular stenosis; 21 patients had tunneled catheter placement for use while healing, whereas 13 were allowed segmental use of their AVF during the perioperative period (1 patient was not yet on dialysis). Early in our experience, AVFs were left under the wound, whereas all but one repaired since early 2013 were left under a lateral flap. All patients were followed by clinical examination and duplex. In the 30-day postoperative period, 2 AVFs (5.7%) became infected requiring excision, 2 occluded (5.7%), 1 day 1 and the other at 24 days out, 1 patient developed steal and required DRIL 1 week postoperatively, and 1 patient died, unrelated to his surgery. Postoperative functional primary patency was 88% (30 of 34). Of the patients needing temporary access catheter, mean time to first fistula use was 44 days. No wound or bleeding complications have occurred in repaired

  15. Automated Segmentation Methods of Drusen to Diagnose Age-Related Macular Degeneration Screening in Retinal Images

    OpenAIRE

    Kim, Young Jae; Kim, Kwang Gi

    2018-01-01

    Existing drusen measurement is difficult to use in clinic because it requires a lot of time and effort for visual inspection. In order to resolve this problem, we propose an automatic drusen detection method to help clinical diagnosis of age-related macular degeneration. First, we changed the fundus image to a green channel and extracted the ROI of the macular area based on the optic disk. Next, we detected the candidate group using the difference image of the median filter within the ROI. We...

  16. The segmentation of the human brain; a message to the neuroimaging community from an adjacent domain of the neurosciences

    NARCIS (Netherlands)

    Nieuwenhuys, R.

    2018-01-01

    Morphological and genoarchitectonic studies have conclusively shown that the human brain (and that of all vertebrates) is segmented i. e. is fundamentally composed of a number of rostrocaudally arranged brain segments or neuromeres. However in the current neuroimaging literature the term

  17. Loosely coupled level sets for retinal layers and drusen segmentation in subjects with dry age-related macular degeneration

    NARCIS (Netherlands)

    Novosel, J.; Wang, Ziyuan; De Jong, Henk; Vermeer, K.A.; van Vliet, L.J.; Styner, Martin A.; Angelini, Elsa D.

    2016-01-01

    Optical coherence tomography (OCT) is used to produce high-resolution three-dimensional images of the retina, which permit the investigation of retinal irregularities. In dry age-related macular degeneration (AMD), a chronic eye disease that causes central vision loss, disruptions such as drusen and

  18. Posteriorly directed shear loads and disc degeneration affect the torsional stiffness of spinal motion segments; a biomechanical modeling study

    NARCIS (Netherlands)

    Homminga, Jasper Johan; Lehr, A.M.; Meijer, Gerdine; Janssen, M.M.A.; Schlösser, T.P.C.; Verkerke, Gijsbertus Jacob; Castelein, R.M.

    2013-01-01

    Objective. To analyze the effects of posterior shear loads, disc degeneration, and the combination of both on spinal torsion stiffness. Summary of Background Data. Scoliosis is a 3-dimensional deformity of the spine that presents itself mainly in adolescent girls and elderly patients. Our concept of

  19. Semiautomated segmentation and analysis of retinal layers in three-dimensional spectral-domain optical coherence tomography images of patients with atrophic age-related macular degeneration.

    Science.gov (United States)

    Hu, Zhihong; Shi, Yue; Nandanan, Kiran; Sadda, Srinivas R

    2017-01-01

    Historically, regular drusen and geographic atrophy (GA) have been recognized as the hallmarks of nonneovascular age-related macular degeneration (AMD). Recent imaging developments have revealed another distinct nonneovascular AMD phenotype, reticular pseudodrusen (RPD). We develop an approach to semiautomatically quantify retinal surfaces associated with various AMD lesions (i.e., regular drusen, RPD, and GA) in spectral domain (SD) optical coherence tomography (OCT) images. More specifically, a graph-based algorithm was used to segment multiple retinal layers in SD-OCT volumes. Varying surface feasibility constraints based on the presegmentation were applied on the double-surface graph search to refine the surface segmentation. The thicknesses of these layers and their correlation with retinal functional measurements, including microperimetry (MP) sensitivity and visual acuity (VA), were investigated. The photoreceptor outer segment layer demonstrated significant thinning with a reduction in MP sensitivity and VA score when atrophic AMD lesions were present. Regular drusen and RPD were separately segmented on SD-OCT images to allow their characteristics and distribution to be studied separately. The mean thickness of regular drusen was found to significantly correlate with the VA score. RPD appeared to be distributed evenly throughout the macula and regular drusen appeared to be more concentrated centrally.

  20. A hybrid segmentation approach for geographic atrophy in fundus auto-fluorescence images for diagnosis of age-related macular degeneration.

    Science.gov (United States)

    Lee, Noah; Laine, Andrew F; Smith, R Theodore

    2007-01-01

    Fundus auto-fluorescence (FAF) images with hypo-fluorescence indicate geographic atrophy (GA) of the retinal pigment epithelium (RPE) in age-related macular degeneration (AMD). Manual quantification of GA is time consuming and prone to inter- and intra-observer variability. Automatic quantification is important for determining disease progression and facilitating clinical diagnosis of AMD. In this paper we describe a hybrid segmentation method for GA quantification by identifying hypo-fluorescent GA regions from other interfering retinal vessel structures. First, we employ background illumination correction exploiting a non-linear adaptive smoothing operator. Then, we use the level set framework to perform segmentation of hypo-fluorescent areas. Finally, we present an energy function combining morphological scale-space analysis with a geometric model-based approach to perform segmentation refinement of false positive hypo- fluorescent areas due to interfering retinal structures. The clinically apparent areas of hypo-fluorescence were drawn by an expert grader and compared on a pixel by pixel basis to our segmentation results. The mean sensitivity and specificity of the ROC analysis were 0.89 and 0.98%.

  1. A level-set method for pathology segmentation in fluorescein angiograms and en face retinal images of patients with age-related macular degeneration

    Science.gov (United States)

    Mohammad, Fatimah; Ansari, Rashid; Shahidi, Mahnaz

    2013-03-01

    The visibility and continuity of the inner segment outer segment (ISOS) junction layer of the photoreceptors on spectral domain optical coherence tomography images is known to be related to visual acuity in patients with age-related macular degeneration (AMD). Automatic detection and segmentation of lesions and pathologies in retinal images is crucial for the screening, diagnosis, and follow-up of patients with retinal diseases. One of the challenges of using the classical level-set algorithms for segmentation involves the placement of the initial contour. Manually defining the contour or randomly placing it in the image may lead to segmentation of erroneous structures. It is important to be able to automatically define the contour by using information provided by image features. We explored a level-set method which is based on the classical Chan-Vese model and which utilizes image feature information for automatic contour placement for the segmentation of pathologies in fluorescein angiograms and en face retinal images of the ISOS layer. This was accomplished by exploiting a priori knowledge of the shape and intensity distribution allowing the use of projection profiles to detect the presence of pathologies that are characterized by intensity differences with surrounding areas in retinal images. We first tested our method by applying it to fluorescein angiograms. We then applied our method to en face retinal images of patients with AMD. The experimental results included demonstrate that the proposed method provided a quick and improved outcome as compared to the classical Chan-Vese method in which the initial contour is randomly placed, thus indicating the potential to provide a more accurate and detailed view of changes in pathologies due to disease progression and treatment.

  2. Automated image alignment and segmentation to follow progression of geographic atrophy in age-related macular degeneration.

    Science.gov (United States)

    Ramsey, David J; Sunness, Janet S; Malviya, Poorva; Applegate, Carol; Hager, Gregory D; Handa, James T

    2014-07-01

    To develop a computer-based image segmentation method for standardizing the quantification of geographic atrophy (GA). The authors present an automated image segmentation method based on the fuzzy c-means clustering algorithm for the detection of GA lesions. The method is evaluated by comparing computerized segmentation against outlines of GA drawn by an expert grader for a longitudinal series of fundus autofluorescence images with paired 30° color fundus photographs for 10 patients. The automated segmentation method showed excellent agreement with an expert grader for fundus autofluorescence images, achieving a performance level of 94 ± 5% sensitivity and 98 ± 2% specificity on a per-pixel basis for the detection of GA area, but performed less well on color fundus photographs with a sensitivity of 47 ± 26% and specificity of 98 ± 2%. The segmentation algorithm identified 75 ± 16% of the GA border correctly in fundus autofluorescence images compared with just 42 ± 25% for color fundus photographs. The results of this study demonstrate a promising computerized segmentation method that may enhance the reproducibility of GA measurement and provide an objective strategy to assist an expert in the grading of images.

  3. Total resection of any segment of the lateral meniscus may cause early cartilage degeneration: Evaluation by magnetic resonance imaging using T2 mapping.

    Science.gov (United States)

    Murakami, Koji; Arai, Yuji; Ikoma, Kazuya; Kato, Kammei; Inoue, Hiroaki; Nakagawa, Shuji; Fujii, Yuta; Ueshima, Keiichiro; Fujiwara, Hiroyoshi; Kubo, Toshikazu

    2018-06-01

    The aim of this study was to perform quantitative evaluation of degeneration of joint cartilage using T2 mapping in magnetic resonance imaging (MRI) after arthroscopic partial resection of the lateral meniscus.The subjects were 21 patients (23 knees) treated with arthroscopic partial resection of the lateral meniscus. MRI was performed for all knees before surgery and 6 months after surgery to evaluate the center of the lateral condyle of the femur in sagittal images for T2 mapping. Ten regions of interest (ROIs) on the articular cartilage were established at 10-degree intervals, from the point at which the femur shaft crossed the lateral femoral condyle joint to the articular cartilage 90° relative to the femur shaft. Preoperative and postoperative T2 values were evaluated at each ROI. Age, sex, body mass index, femorotibial angle, Tegner score, and amount of meniscal resection were evaluated when the T2 value increased more than 6% at 30°.T2 values at approximately 10 °, 20 °, 30 °, 40 °, 50 °, and 60 ° degrees relative to the anatomical axis of the femur were significantly greater postoperatively (3.1, 3.6, 5.5, 4.4, 5.0, 6.4%, respectively) than preoperatively. A >6% increase at 30° was associated with total resection of any segment of the meniscus.Degeneration of the articular cartilage, as shown by the disorganization of collagen arrays at positions approximately 10 °, 20 °, 30 °, 40 °, 50 °, and 60 ° relative to the anatomical axis of the femur, may start soon after arthroscopic lateral meniscectomy. Total resection of any segment of the lateral meniscus may cause T2 elevation of articular cartilage of lateral femoral condyle.

  4. Segmentation error and macular thickness measurements obtained with spectral-domain optical coherence tomography devices in neovascular age-related macular degeneration

    Directory of Open Access Journals (Sweden)

    Moosang Kim

    2013-01-01

    Full Text Available Purpose: To evaluate frequency and severity of segmentation errors of two spectral-domain optical coherence tomography (SD-OCT devices and error effect on central macular thickness (CMT measurements. Materials and Methods: Twenty-seven eyes of 25 patients with neovascular age-related macular degeneration, examined using the Cirrus HD-OCT and Spectralis HRA + OCT, were retrospectively reviewed. Macular cube 512 × 128 and 5-line raster scans were performed with the Cirrus and 512 × 25 volume scans with the Spectralis. Frequency and severity of segmentation errors were compared between scans. Results: Segmentation error frequency was 47.4% (baseline, 40.7% (1 month, 40.7% (2 months, and 48.1% (6 months for the Cirrus, and 59.3%, 62.2%, 57.8%, and 63.7%, respectively, for the Spectralis, differing significantly between devices at all examinations (P < 0.05, except at baseline. Average error score was 1.21 ± 1.65 (baseline, 0.79 ± 1.18 (1 month, 0.74 ± 1.12 (2 months, and 0.96 ± 1.11 (6 months for the Cirrus, and 1.73 ± 1.50, 1.54 ± 1.35, 1.38 ± 1.40, and 1.49 ± 1.30, respectively, for the Spectralis, differing significantly at 1 month and 2 months (P < 0.02. Automated and manual CMT measurements by the Spectralis were larger than those by the Cirrus. Conclusions: The Cirrus HD-OCT had a lower frequency and severity of segmentation error than the Spectralis HRA + OCT. SD-OCT error should be considered when evaluating retinal thickness.

  5. Comprehensive comparing percutaneous endoscopic lumbar discectomy with posterior lumbar internal fixation for treatment of adjacent segment lumbar disc prolapse with stable retrolisthesis

    Science.gov (United States)

    Sun, Yapeng; Zhang, Wei; Qie, Suhui; Zhang, Nan; Ding, Wenyuan; Shen, Yong

    2017-01-01

    Abstract The study was to comprehensively compare the postoperative outcome and imaging parameter characters in a short/middle period between the percutaneous endoscopic lumbar discectomy (PELD) and the internal fixation of bone graft fusion (the most common form is posterior lumbar interbody fusion [PLIF]) for the treatment of adjacent segment lumbar disc prolapse with stable retrolisthesis after a previous lumbar internal fixation surgery. In this retrospective case-control study, we collected the medical records from 11 patients who received PELD operation (defined as PELD group) for and from 13 patients who received the internal fixation of bone graft fusion of lumbar posterior vertebral lamina decompression (defined as control group) for the treatment of the lumbar disc prolapse combined with stable retrolisthesis at Department of Spine Surgery, the Third Hospital of Hebei Medical University (Shijiazhuang, China) from May 2010 to December 2015. The operation time, the bleeding volume of perioperation, and the rehabilitation days of postoperation were compared between 2 groups. Before and after surgery at different time points, ODI, VAS index, and imaging parameters (including Taillard index, inter-vertebral height, sagittal dislocation, and forward bending angle of lumbar vertebrae) were compared. The average operation time, the blooding volume, and the rehabilitation days of postoperation were significantly less in PELD than in control group. The ODI and VAS index in PELD group showed a significantly immediate improving on the same day after the surgery. However, Taillard index, intervertebral height, sagittal dislocation in control group showed an immediate improving after surgery, but no changes in PELD group till 12-month after surgery. The forward bending angle of lumbar vertebrae was significantly increased and decreased in PELD and in control group, respectively. PELD operation was superior in terms of operation time, bleeding volume, recovery period

  6. Comprehensive comparing percutaneous endoscopic lumbar discectomy with posterior lumbar internal fixation for treatment of adjacent segment lumbar disc prolapse with stable retrolisthesis: A retrospective case-control study.

    Science.gov (United States)

    Sun, Yapeng; Zhang, Wei; Qie, Suhui; Zhang, Nan; Ding, Wenyuan; Shen, Yong

    2017-07-01

    The study was to comprehensively compare the postoperative outcome and imaging parameter characters in a short/middle period between the percutaneous endoscopic lumbar discectomy (PELD) and the internal fixation of bone graft fusion (the most common form is posterior lumbar interbody fusion [PLIF]) for the treatment of adjacent segment lumbar disc prolapse with stable retrolisthesis after a previous lumbar internal fixation surgery.In this retrospective case-control study, we collected the medical records from 11 patients who received PELD operation (defined as PELD group) for and from 13 patients who received the internal fixation of bone graft fusion of lumbar posterior vertebral lamina decompression (defined as control group) for the treatment of the lumbar disc prolapse combined with stable retrolisthesis at Department of Spine Surgery, the Third Hospital of Hebei Medical University (Shijiazhuang, China) from May 2010 to December 2015. The operation time, the bleeding volume of perioperation, and the rehabilitation days of postoperation were compared between 2 groups. Before and after surgery at different time points, ODI, VAS index, and imaging parameters (including Taillard index, inter-vertebral height, sagittal dislocation, and forward bending angle of lumbar vertebrae) were compared.The average operation time, the blooding volume, and the rehabilitation days of postoperation were significantly less in PELD than in control group. The ODI and VAS index in PELD group showed a significantly immediate improving on the same day after the surgery. However, Taillard index, intervertebral height, sagittal dislocation in control group showed an immediate improving after surgery, but no changes in PELD group till 12-month after surgery. The forward bending angle of lumbar vertebrae was significantly increased and decreased in PELD and in control group, respectively.PELD operation was superior in terms of operation time, bleeding volume, recovery period, and financial

  7. Semiautomatic Segmentation of Rim Area Focal Hyperautofluorescence Predicts Progression of Geographic Atrophy Due to Dry Age-Related Macular Degeneration.

    Science.gov (United States)

    Allingham, Michael J; Nie, Qing; Lad, Eleonora M; Izatt, Daniel J; Mettu, Priyatham S; Cousins, Scott W; Farsiu, Sina

    2016-04-01

    To develop image analysis software usable by nonexpert graders to segment geographic atrophy (GA) from dry AMD and to quantify rim area focal hyperautofluorescence (RAFH) surrounding GA on fundus autofluorescence (FAF) images. To compare the GA progression predictions based on RAFH with those of a validated qualitative classification system. Retrospective analysis of serial FAF images from 49 eyes of 30 subjects with GA was performed using MATLAB-based software (MathWorks, Natick, MA, USA). Correlation between RAFH and progression of GA was analyzed using Spearman correlation. Comparisons of lesion growth rate between RAFH tertiles used generalized estimating equations and Kruskal-Wallis testing. Interobserver variability in lesion size, growth rate and RAFH were compared between two expert and one nonexpert grader using Bland-Altman statistics. Rim area focal hyperautofluorescence was positively correlated with GA progression rate (ρ = 0.49, P < 0.001). Subjects in the middle or highest RAFH tertile were at greater risk of progression (P = 0.005 and P = 0.001, respectively). Mean difference in RAFH was 0.012 between expert and -0.005 to 0.017 between expert and nonexperts. Mean difference in lesion size (mm2) was 0.11 between expert and -0.29 to 0.41 between expert and nonexperts. Mean difference in lesion growth rate (mm2/mo) was 0.0098 between expert and -0.027 to 0.037 between expert and nonexperts. Risk stratification based on RAFH tertile was 96% identical across all graders. Our semiautomated image analysis software facilitates stratification of progression risk based on RAFH and enabled a nonexpert grader with minimal training to obtain results comparable to expert graders. Predictions based on RAFH were similar to those of a validated qualitative classification system.

  8. Disc degeneration: current surgical options

    Directory of Open Access Journals (Sweden)

    C Schizas

    2010-10-01

    Full Text Available Chronic low back pain attributed to lumbar disc degeneration poses a serious challenge to physicians. Surgery may be indicated in selected cases following failure of appropriate conservative treatment. For decades, the only surgical option has been spinal fusion, but its results have been inconsistent. Some prospective trials show superiority over usual conservative measures while others fail to demonstrate its advantages. In an effort to improve results of fusion and to decrease the incidence of adjacent segment degeneration, total disc replacement techniques have been introduced and studied extensively. Short-term results have shown superiority over some fusion techniques. Mid-term results however tend to show that this approach yields results equivalent to those of spinal fusion. Nucleus replacement has gained some popularity initially, but evidence on its efficacy is scarce. Dynamic stabilisation, a technique involving less rigid implants than in spinal fusion and performed without the need for bone grafting, represents another surgical option. Evidence again is lacking on its superiority over other surgical strategies and conservative measures. Insertion of interspinous devices posteriorly, aiming at redistributing loads and relieving pain, has been used as an adjunct to disc removal surgery for disc herniation. To date however, there is no clear evidence on their efficacy. Minimally invasive intradiscal thermocoagulation techniques have also been tried, but evidence of their effectiveness is questioned. Surgery using novel biological solutions may be the future of discogenic pain treatment. Collaboration between clinicians and basic scientists in this multidisciplinary field will undoubtedly shape the future of treating symptomatic disc degeneration.

  9. Effect of Interbody Fusion on the Remaining Discs of the Lumbar Spine in Subjects with Disc Degeneration.

    Science.gov (United States)

    Ryu, Robert; Techy, Fernando; Varadarajan, Ravikumar; Amirouche, Farid

    2016-02-01

    To study effects (stress loads) of lumbar fusion on the remaining segments (adjacent or not) of the lumbar spine in the setting of degenerated adjacent discs. A lumbar spine finite element model was built and validated. The full model of the lumbar spine was a parametric finite element model of segments L 1-5 . Numerous hypothetical combinations of one-level lumbar spine fusion and one-level disc degeneration were created. These models were subjected to 10 Nm flexion and extension moments and the stresses on the endplates and consequently on the intervertebral lumbar discs measured. These values were compared to the stresses on healthy lumbar spine discs under the same load and fusion scenarios. Increased stress at endplates was observed only in the settings of L4-5 fusion and L3-4 disc degeneration (8% stress elevation at L2,3 in flexion or extension, and 25% elevation at L3,4 in flexion only). All other combinations showed less endplate stress than did the control model. For fusion at L3-4 and degeneration at L4-5 , the stresses in the endplates at the adjacent level inferior to the fused disc decreased for both loading disc height reductions. Stresses in flexion decreased after fusion by 29.5% and 25.8% for degeneration I and II, respectively. Results for extension were similar. For fusion at L2-3 and degeneration at L4-5 , stresses in the endplates decreased more markedly at the degenerated (30%), than at the fused level (14%) in the presence of 25% disc height reduction and 10 Nm flexion, whereas in extension stresses decreased more at the fused (24.3%) than the degenerated level (5.86%). For fusion at L3-4 and degeneration at L2-3 , there were no increases in endplate stress in any scenario. For fusion at L4-5 and degeneration at L3-4 , progression of degeneration from I to II had a significant effect only in flexion. A dramatic increase in stress was noted in the endplates of the degenerated disc (L3-4 ) in flexion for degeneration II. Stresses are greater

  10. Striatonigral Degeneration

    Science.gov (United States)

    ... See More About Research The NINDS supports and conducts research on disorders of the brain and nervous system such as striatonigral degeneration. This research ... Publications Definition Striatonigral ...

  11. Mechanical deformation and glycosaminoglycan content changes in a rabbit annular puncture disc degeneration model.

    Science.gov (United States)

    Chan, Deva D; Khan, Safdar N; Ye, Xiaojing; Curtiss, Shane B; Gupta, Munish C; Klineberg, Eric O; Neu, Corey P

    2011-08-15

    Evaluation of degenerated intervertebral discs from a rabbit annular puncture model by using specialized magnetic resonance imaging (MRI) techniques, including displacement encoding with stimulated echoes and a fast-spin echo (DENSE-FSE) acquisition and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). To evaluate a rabbit disc degeneration model by using various MRI techniques. To determine the displacements and strains, spin-lattice relaxation time (T1), and glycosaminoglycan (GAG) distribution of degenerated discs as compared to normal and adjacent level discs. Annular puncture of the intervertebral disc produces disc degeneration in rabbits. DENSE-FSE has been previously demonstrated in articular cartilage for the measurement of soft tissue displacements and strains. MRI also can measure the T1 of tissue, and dGEMRIC can quantify GAG concentration in cartilage. METHODS.: In eight New Zealand white rabbits, the annulus fibrosis of a lumbar disc was punctured. After 4 weeks, the punctured and cranially adjacent motion segments were isolated for MRI and histology. MRI was used to estimate the disc volume and map T1. DENSE-FSE was used to determine displacements for the estimation of strains. dGEMRIC was then used to determine GAG distributions. Histology and standard MRI indicated degeneration in punctured discs. Disc volume increased significantly at 4 weeks after the puncture. Displacement of the nucleus pulposus was distinct from that of the annulus fibrosis in most untreated discs but not in punctured discs. T1 was significantly higher and GAG concentration significantly lower in punctured discs compared with untreated adjacent level discs. Noninvasive and quantitative MRI techniques can be used to evaluate the mechanical and biochemical changes that occur with animal models of disc degeneration. DENSE-FSE, dGEMRIC, and similar techniques have potential for evaluating the progression of disc degeneration and the efficacy of treatments.

  12. Development of Land Segmentation, Stream-Reach Network, and Watersheds in Support of Hydrological Simulation Program-Fortran (HSPF) Modeling, Chesapeake Bay Watershed, and Adjacent Parts of Maryland, Delaware, and Virginia

    Science.gov (United States)

    Martucci, Sarah K.; Krstolic, Jennifer L.; Raffensperger, Jeff P.; Hopkins, Katherine J.

    2006-01-01

    The U.S. Geological Survey, U.S. Environmental Protection Agency Chesapeake Bay Program Office, Interstate Commission on the Potomac River Basin, Maryland Department of the Environment, Virginia Department of Conservation and Recreation, Virginia Department of Environmental Quality, and the University of Maryland Center for Environmental Science are collaborating on the Chesapeake Bay Regional Watershed Model, using Hydrological Simulation Program - FORTRAN to simulate streamflow and concentrations and loads of nutrients and sediment to Chesapeake Bay. The model will be used to provide information for resource managers. In order to establish a framework for model simulation, digital spatial datasets were created defining the discretization of the model region (including the Chesapeake Bay watershed, as well as the adjacent parts of Maryland, Delaware, and Virginia outside the watershed) into land segments, a stream-reach network, and associated watersheds. Land segmentation was based on county boundaries represented by a 1:100,000-scale digital dataset. Fifty of the 254 counties and incorporated cities in the model region were divided on the basis of physiography and topography, producing a total of 309 land segments. The stream-reach network for the Chesapeake Bay watershed part of the model region was based on the U.S. Geological Survey Chesapeake Bay SPARROW (SPAtially Referenced Regressions On Watershed attributes) model stream-reach network. Because that network was created only for the Chesapeake Bay watershed, the rest of the model region uses a 1:500,000-scale stream-reach network. Streams with mean annual streamflow of less than 100 cubic feet per second were excluded based on attributes from the dataset. Additional changes were made to enhance the data and to allow for inclusion of stream reaches with monitoring data that were not part of the original network. Thirty-meter-resolution Digital Elevation Model data were used to delineate watersheds for each

  13. Adjacent Lumbar Disc Herniation after Lumbar Short Spinal Fusion

    Directory of Open Access Journals (Sweden)

    Koshi Ninomiya

    2014-01-01

    Full Text Available A 70-year-old outpatient presented with a chief complaint of sudden left leg motor weakness and sensory disturbance. He had undergone L4/5 posterior interbody fusion with L3–5 posterior fusions for spondylolisthesis 3 years prior, and the screws were removed 1 year later. He has been followed up for 3 years, and there had been no adjacent segment problems before this presentation. Lumbar magnetic resonance imaging (MRI showed a large L2/3 disc hernia descending to the L3/4 level. Compared to the initial MRI, this hernia occurred in an “intact” disc among multilevel severely degenerated discs. Right leg paresis and bladder dysfunction appeared a few days after admission. Microscopic lumbar disc herniotomy was performed. The right leg motor weakness improved just after the operation, but the moderate left leg motor weakness and difficulty in urination persisted.

  14. Cerebellar Degeneration

    Science.gov (United States)

    ... FARA) National Ataxia Foundation (NAF) National Multiple Sclerosis Society See all related organizations Publications Degeneración cerebelosa Order NINDS Publications Definition Cerebellar degeneration is a process in which neurons ( ...

  15. Macular degeneration

    Science.gov (United States)

    The macula is the part of the retina that distinguishes fine details at the center of the field of vision. Macular degeneration results from a partial breakdown of the insulating layer between the retina and the choroid layer of ...

  16. Segmented inner plexiform layer thickness as a potential biomarker to evaluate open-angle glaucoma: Dendritic degeneration of retinal ganglion cell.

    Directory of Open Access Journals (Sweden)

    Eun Kyoung Kim

    Full Text Available To evaluate the changes of retinal nerve fiber layer (RNFL, ganglion cell layer (GCL, inner plexiform layer (IPL, and ganglion cell-inner plexiform layer (GCIPL thicknesses and compare structure-function relationships of 4 retinal layers using spectral-domain optical coherence tomography (SD-OCT in macular region of glaucoma patients.In cross-sectional study, a total of 85 eyes with pre-perimetric to advanced glaucoma and 26 normal controls were enrolled. The glaucomatous eyes were subdivided into three groups according to the severity of visual field defect: a preperimetric glaucoma group, an early glaucoma group, and a moderate to advanced glaucoma group. RNFL, GCL, IPL, and GCIPL thicknesses were measured at the level of the macula by the Spectralis (Heidelberg Engineering, Heidelberg, Germany SD-OCT with automated segmentation software. For functional evaluation, corresponding mean sensitivity (MS values were measured using 24-2 standard automated perimetry (SAP.RNFL, GCL, IPL, and GCIPL thicknesses were significantly different among 4 groups (P < .001. Macular structure losses were positively correlated with the MS values of the 24-2 SAP for RNFL, GCL, IPL, and GCIPL (R = 0.553, 0.636, 0.648 and 0.646, respectively, P < .001. In regression analysis, IPL and GCIPL thicknesses showed stronger association with the corresponding MS values of 24-2 SAP compared with RNFL and GCL thicknesses (R2 = 0.420, P < .001 for IPL; R2 = 0.417, P< .001 for GCIPL thickness.Segmented IPL thickness was significantly associated with the degree of glaucoma. Segmental analysis of the inner retinal layer including the IPL in macular region may provide valuable information for evaluating glaucoma.

  17. Segmented inner plexiform layer thickness as a potential biomarker to evaluate open-angle glaucoma: Dendritic degeneration of retinal ganglion cell.

    Science.gov (United States)

    Kim, Eun Kyoung; Park, Hae-Young Lopilly; Park, Chan Kee

    2017-01-01

    To evaluate the changes of retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), and ganglion cell-inner plexiform layer (GCIPL) thicknesses and compare structure-function relationships of 4 retinal layers using spectral-domain optical coherence tomography (SD-OCT) in macular region of glaucoma patients. In cross-sectional study, a total of 85 eyes with pre-perimetric to advanced glaucoma and 26 normal controls were enrolled. The glaucomatous eyes were subdivided into three groups according to the severity of visual field defect: a preperimetric glaucoma group, an early glaucoma group, and a moderate to advanced glaucoma group. RNFL, GCL, IPL, and GCIPL thicknesses were measured at the level of the macula by the Spectralis (Heidelberg Engineering, Heidelberg, Germany) SD-OCT with automated segmentation software. For functional evaluation, corresponding mean sensitivity (MS) values were measured using 24-2 standard automated perimetry (SAP). RNFL, GCL, IPL, and GCIPL thicknesses were significantly different among 4 groups (P < .001). Macular structure losses were positively correlated with the MS values of the 24-2 SAP for RNFL, GCL, IPL, and GCIPL (R = 0.553, 0.636, 0.648 and 0.646, respectively, P < .001). In regression analysis, IPL and GCIPL thicknesses showed stronger association with the corresponding MS values of 24-2 SAP compared with RNFL and GCL thicknesses (R2 = 0.420, P < .001 for IPL; R2 = 0.417, P< .001 for GCIPL thickness). Segmented IPL thickness was significantly associated with the degree of glaucoma. Segmental analysis of the inner retinal layer including the IPL in macular region may provide valuable information for evaluating glaucoma.

  18. Unilateral lumbar spondylolysis on radiography and MRI: emphasis on morphologic differences according to involved segment.

    Science.gov (United States)

    Park, Ji Seon; Moon, Sung Kyoung; Jin, Wook; Ryu, Kyung Nam

    2010-01-01

    The objective of our study was to retrospectively compare the radiography and MRI findings of unilateral spondylolysis in the upper lumbar segment and in the lower lumbar segment and to consider how these radiologic findings can be applied in the diagnosis of unilateral spondylolysis. Thirty patients with unilateral lumbar spondylolysis were categorized into one of two groups according to the lumbar levels involved with pars interarticularis defects: group A (L1, L2, and L3) or group B (L4 and L5). On radiographs, we evaluated contour bulging of the affected pars interarticularis, reactive sclerosis in the contralateral pedicle, anterolisthesis of the involved vertebra, and deviation of the spinous process. On MRI, we assessed pseudoarticulation of the pars interarticularis defect, uneven distribution of posterior epidural fat, the interspinous distance between adjacent segments, facet and disk degeneration in adjacent segments, and other anomalous changes. Among the 63 patients with unilateral spondylolysis, the upper lumbar segment was involved in 29 and the lower lumbar segment, in 34. Group A often displayed contour bulging of the affected pars interarticularis, reactive sclerosis of the contralateral pedicle, and contralateral deviation of the spinous process, all of which were easily detectable on radiography. Group B frequently showed anterolisthesis, pseudoarticulation of the pars interarticularis defect, adjacent facet-disk degeneration, and other anomalous changes that were well observed on MRI. Unilateral lumbar spondylolysis displayed radiologic differences in morphology of the isthmic defect itself and in ancillary findings of the adjacent structures based on the segment involved. Recognition of different ancillary features of unilateral spondylolysis with the use of a feasible diagnostic tool can be helpful for the diagnosis of cases in which a direct sign of isthmic defect is equivocal.

  19. [Partial nucleotomy of the ovine disc as an in vivo model for disc degeneration].

    Science.gov (United States)

    Guder, E; Hill, S; Kandziora, F; Schnake, K J

    2009-01-01

    The aim of this study was to develop a suitable animal model for the clinical situation of progressive disc degeneration after microsurgical nucleotomy. Twenty sheep underwent standardised partial anterolateral nucleotomy at lumbar segment 3/4. After randomisation, 10 animals were sacrificed after 12 weeks (group 1). The remainder was sacrificed after 48 weeks (group 2). For radiological examination X-rays, MRI and post-mortem CT scans were performed. Lumbar discs L 3/4 with adjacent subchondral trabecular bone were harvested and analysed macroscopically and histologically. An image-analysing computer program was used to measure histomorphometric indices of bone structure. 17 segments could be evaluated. After 12 weeks (group 1) histological and radiological degenerative disc changes were noted. After 48 weeks (group 2), radiological signs in MRI reached statistical significance. Furthermore, group 2 showed significantly more osteophyte formations in CT scans. Histomorphometric changes of the disc and the adjacent vertebral bone structure suggest a significant progressive degenerative remodelling. The facet joints did not show any osteoarthrosis after 48 weeks. Partial nucleotomy of the ovine lumbar disc leads to radiological and histological signs of disc degeneration similar to those seen in humans after microsurgical nucleotomy. The presented in vivo model may be useful to evaluate new orthopaedic treatment strategies.

  20. Motor axon excitability during Wallerian degeneration

    DEFF Research Database (Denmark)

    Moldovan, Mihai; Alvarez, Susana; Krarup, Christian

    2008-01-01

    Axonal loss and degeneration are major factors in determining long-term outcome in patients with peripheral nerve disorders or injury. Following loss of axonal continuity, the isolated nerve stump distal to the lesion undergoes Wallerian degeneration in several phases. In the initial 'latent' phase......, action potential propagation and structural integrity of the distal segment are maintained. The aim of this study was to investigate in vivo the changes in membrane function of motor axons during the 'latent' phase of Wallerian degeneration. Multiple indices of axonal excitability of the tibial nerve...

  1. Macular degeneration (image)

    Science.gov (United States)

    ... macula in the back of the eye. The macula is important for clear central vision, allowing an individual to see fine details. There are two types of macular degeneration, dry and wet. Dry macular degeneration is more ...

  2. IMMEDIATE RECIPROCAL CHANGES AT ADJACENT LEVEL FOLLOWING SINGLE-LEVEL ALIF

    Directory of Open Access Journals (Sweden)

    Enrique Vargas Uribe

    2015-12-01

    Full Text Available Objective : To assess the segmental sagittal parameters and the adjacent mobile segment after interbody fusion by anterior approach in single-level L5-S1. Methods : Retrospective study. Inclusion: Interbody fusion by anterior approach (10°/15° angle, due to DDD, low-grade spondylolisthesis and/or stenosis without prior lumbar fusion. Thirty-five cases were included (25 women; mean age 47±15 years. Analysis of lumbar radiographs were performed preoperatively and 3 months after surgery. The following parameters were evaluated: lumbar lordosis; segmental lordosis L4-L5 and L5-S1; sacral and L5 slope. Two independent evaluators made the measurements. Student's t test was used. Results : There was correction of lordosis at the L5-S1 level, from an average of 19° prior to surgery to 28° three months after surgery (p<0.001. It was observed reduction of the L4-L5 angle from 17° to 14° (p <0.001. Moreover, there was a small, but statistically significant, reduction of L5 inclination from 17 ° to 13 ° (p=0.007 and increase in the sacral slope from 37° to 40° (p=0.002. The change of total lumbar lordosis was not significant: 52° versus 53° (p=0.461. Before surgical correction, lordosis of the L5-S1 level contributed, on average, 37% of lumbar lordosis, and after, 54% (p<0.001. The L4-L5 level accounted for 34% and decreased to 24% (p<0.001. Conclusion : In the group studied, it was observed a decrease in lordosis of the adjacent mobile level following the treatment of the degenerate level by anterior interbody fusion and concomitant increase in lordosis.

  3. Is Preventative Long-Segment Surgery for Multi-Level Spondylolysis Necessary? A Finite Element Analysis Study.

    Directory of Open Access Journals (Sweden)

    Jianqiang Mo

    Full Text Available For multi-level spondylolysis patients, surgeons commonly choose to fix all the segments with pars interarticularis defect even those without slippage and not responsible for clinical symptoms. In this study, we tried to study the necessity of the preventative long-segment surgery for the defected segment without slippage in treatment of multi-level spondylolysis patients from a biomechanical perspective.We established a bi-level spondylolysis model with pars defects at L4 and L5 segments, and simulated posterior lumbar interbody fusion (PLIF and pedicle screw fixation at L5-S1 level. Then we compared the biomechanical changes at L4 segment before and after surgery in neutral, flexion, extension, lateral bending and axial rotation position.The stress on L4 pars interarticularis was very similar before and after surgery, and reached the highest in axial rotation. The L3-L4 intradiscal pressure was almost the same, while L4-L5 intradiscal pressure changed a little in lateral bending (increase from 1.993 to 2.160 MPa and axial rotation (decrease from 1.639 to 1.307 MPa after surgery. The PLIF surgery caused a little increase of range of motion at adjacent L4-L5 and L3-L4 levels, but the change is very tiny (1 degree.The PLIF surgery will not cause significant biomechanical change at adjacent segment with pars defect in multi-level spondylolysis. On the contrary, excessive long-segment surgery will damage surrounding soft tissues which are important for maintaining the stability of spine. So a preventative long-segment surgery is not necessary for multi-level spondylolysis as long as there are no soft tissue degeneration signs at adjacent level.

  4. Is Preventative Long-Segment Surgery for Multi-Level Spondylolysis Necessary? A Finite Element Analysis Study.

    Science.gov (United States)

    Mo, Jianqiang; Zhang, Wen; Zhong, Dongyan; Xu, Hao; Wang, Lan; Yu, Jia; Luo, Zongping

    2016-01-01

    For multi-level spondylolysis patients, surgeons commonly choose to fix all the segments with pars interarticularis defect even those without slippage and not responsible for clinical symptoms. In this study, we tried to study the necessity of the preventative long-segment surgery for the defected segment without slippage in treatment of multi-level spondylolysis patients from a biomechanical perspective. We established a bi-level spondylolysis model with pars defects at L4 and L5 segments, and simulated posterior lumbar interbody fusion (PLIF) and pedicle screw fixation at L5-S1 level. Then we compared the biomechanical changes at L4 segment before and after surgery in neutral, flexion, extension, lateral bending and axial rotation position. The stress on L4 pars interarticularis was very similar before and after surgery, and reached the highest in axial rotation. The L3-L4 intradiscal pressure was almost the same, while L4-L5 intradiscal pressure changed a little in lateral bending (increase from 1.993 to 2.160 MPa) and axial rotation (decrease from 1.639 to 1.307 MPa) after surgery. The PLIF surgery caused a little increase of range of motion at adjacent L4-L5 and L3-L4 levels, but the change is very tiny (1 degree). The PLIF surgery will not cause significant biomechanical change at adjacent segment with pars defect in multi-level spondylolysis. On the contrary, excessive long-segment surgery will damage surrounding soft tissues which are important for maintaining the stability of spine. So a preventative long-segment surgery is not necessary for multi-level spondylolysis as long as there are no soft tissue degeneration signs at adjacent level.

  5. 3T MR 3D-FIESTA demonstrating cranial nerves in cisternal segment and their relationship with adjacent lesions%3T MR三维稳态进动快速成像序列显示脑池段颅神经及其与周围病变的关系

    Institute of Scientific and Technical Information of China (English)

    惠毅毅; 王庆征; 李传亭; 刘传梅; 张红

    2012-01-01

    Objective To investigate the usefulness of 3T MR 3D-FIESTA in displaying the relationship between the nerves in posterior and middle fossa and rheir adjacent lesions. Methods 34 cases of intracranial lesions in posterior and middle fossa were study with FSE T1W1,FSE T2WI and 3D-FIESTA sequences in 3T MR. The relationship bctween the lesions and the cranial nerves in cisternal segment were confirmed with surgery. Results 34 patients mainly showed 48 lesions on MR imaging. 9 cranial nerves were embedded by its adjacent lesions. 51 were pushed. 25 nerves were involved, and lesions were adjacent to 10 nerves. 23 patients underwent surgery in all 34 cases. The accuracy of 3D-FIESTA imag-ings in demonstrating relationship between cranial nerves with adjacent lesions were 5/6. 26/28. 3/3. 12/13. Conclusion 3T MR 3D-FIESTA imaging could depict the relationship between the nerves in cisternal segment and its adjacent lesions correctly, and it is useful in preoperative evaluation and treatment of intracranial lesions.%目的 探讨3T MR三维稳态进动快速成像(3D-FIESTA)序列显示中、后颅窝颅神经及其与周围病变关系的价值.方法 对34例颅内脑外病变的患者行反转恢复SE T1WI、FSE T2 WI及3D-FIESTA序列扫描.脑池段颅神经与周围病变的关系情况与手术结果相对照.结果 34例患者中共48处病变,3D-FIESTA序列显示9条神经被周围病变包绕.51条颅神经被压迫.与病变相邻的颅神经有10条,病变累及其邻近25条神经;其中23例患者行手术治疗,手术与MR图像对照.3D-FIESTA显示颅神经与周围病变关系的准确性分别为5/6、26/28、3/3、12/13.结论 3T MR 3D-FI-ESTA序列可以正确显示脑池段颅神经及其与周围病变的关系.对治疗前评估及病变的治疗有重要的应用价值.

  6. Segmented rail linear induction motor

    Science.gov (United States)

    Cowan, Jr., Maynard; Marder, Barry M.

    1996-01-01

    A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces.

  7. Degenerate nonlinear diffusion equations

    CERN Document Server

    Favini, Angelo

    2012-01-01

    The aim of these notes is to include in a uniform presentation style several topics related to the theory of degenerate nonlinear diffusion equations, treated in the mathematical framework of evolution equations with multivalued m-accretive operators in Hilbert spaces. The problems concern nonlinear parabolic equations involving two cases of degeneracy. More precisely, one case is due to the vanishing of the time derivative coefficient and the other is provided by the vanishing of the diffusion coefficient on subsets of positive measure of the domain. From the mathematical point of view the results presented in these notes can be considered as general results in the theory of degenerate nonlinear diffusion equations. However, this work does not seek to present an exhaustive study of degenerate diffusion equations, but rather to emphasize some rigorous and efficient techniques for approaching various problems involving degenerate nonlinear diffusion equations, such as well-posedness, periodic solutions, asympt...

  8. Hyaline cartilage degenerates after autologous osteochondral transplantation.

    Science.gov (United States)

    Tibesku, C O; Szuwart, T; Kleffner, T O; Schlegel, P M; Jahn, U R; Van Aken, H; Fuchs, S

    2004-11-01

    Autologous osteochondral grafting is a well-established clinical procedure to treat focal cartilage defects in patients, although basic research on this topic remains sparse. The aim of the current study was to evaluate (1) histological changes of transplanted hyaline cartilage of osteochondral grafts and (2) the tissue that connects the transplanted cartilage with the adjacent cartilage in a sheep model. Both knee joints of four sheep were opened surgically and osteochondral grafts were harvested and simultaneously transplanted to the contralateral femoral condyle. The animals were sacrificed after three months and the received knee joints were evaluated histologically. Histological evaluation showed a complete ingrowth of the osseous part of the osteochondral grafts. A healing or ingrowth at the level of the cartilage could not be observed. Histological evaluation of the transplanted grafts according to Mankin revealed significantly more and more severe signs of degeneration than the adjacent cartilage, such as cloning of chondrocytes and irregularities of the articular surface. We found no connecting tissue between the transplanted and the adjacent cartilage and histological signs of degeneration of the transplanted hyaline cartilage. In the light of these findings, long-term results of autologous osteochondral grafts in human beings have to be followed critically.

  9. Laenderyggens degeneration og radiologi

    DEFF Research Database (Denmark)

    Jacobsen, Steffen; Gosvig, Kasper Kjaerulf; Sonne-Holm, Stig

    2006-01-01

    Low back pain (LBP) is one of the most common conditions, and at the same time one of the most complex nosological entities. The lifetime prevalence is approximately 80%, and radiological features of lumbar degeneration are almost universal in adults. The individual risk factors for LBP and signi...... is cyclic: exacerbations relieved by asymptomatic periods. New imaging modalities, including the combination of MR imaging and multiplanar 3-D CT scans, have broadened our awareness of possible pain-generating degenerative processes of the lumbar spine other than disc degeneration....

  10. On Degenerate Partial Differential Equations

    OpenAIRE

    Chen, Gui-Qiang G.

    2010-01-01

    Some of recent developments, including recent results, ideas, techniques, and approaches, in the study of degenerate partial differential equations are surveyed and analyzed. Several examples of nonlinear degenerate, even mixed, partial differential equations, are presented, which arise naturally in some longstanding, fundamental problems in fluid mechanics and differential geometry. The solution to these fundamental problems greatly requires a deep understanding of nonlinear degenerate parti...

  11. Intacs for early pellucid marginal degeneration.

    Science.gov (United States)

    Kymionis, George D; Aslanides, Ioannis M; Siganos, Charalambos S; Pallikaris, Ioannis G

    2004-01-01

    A 42-year-old man had Intacs (Addition Technology Inc.) implantation for early pellucid marginal degeneration (PMD). Two Intacs segments (0.45 mm thickness) were inserted uneventfully in the fashion typically used for low myopia correction (nasal-temporal). Eleven months after the procedure, the uncorrected visual acuity was 20/200, compared with counting fingers preoperatively, while the best spectacle-corrected visual acuity improved to 20/25 from 20/50. Corneal topographic pattern also improved. Although the results are encouraging, concern still exists regarding the long-term effect of this approach for the management of patients with PMD.

  12. A novel line segment detection algorithm based on graph search

    Science.gov (United States)

    Zhao, Hong-dan; Liu, Guo-ying; Song, Xu

    2018-02-01

    To overcome the problem of extracting line segment from an image, a method of line segment detection was proposed based on the graph search algorithm. After obtaining the edge detection result of the image, the candidate straight line segments are obtained in four directions. For the candidate straight line segments, their adjacency relationships are depicted by a graph model, based on which the depth-first search algorithm is employed to determine how many adjacent line segments need to be merged. Finally we use the least squares method to fit the detected straight lines. The comparative experimental results verify that the proposed algorithm has achieved better results than the line segment detector (LSD).

  13. Laenderyggens degeneration og radiologi

    DEFF Research Database (Denmark)

    Jacobsen, Steffen; Gosvig, Kasper Kjaerulf; Sonne-Holm, Stig

    2006-01-01

    Low back pain (LBP) is one of the most common conditions, and at the same time one of the most complex nosological entities. The lifetime prevalence is approximately 80%, and radiological features of lumbar degeneration are almost universal in adults. The individual risk factors for LBP and signi......Low back pain (LBP) is one of the most common conditions, and at the same time one of the most complex nosological entities. The lifetime prevalence is approximately 80%, and radiological features of lumbar degeneration are almost universal in adults. The individual risk factors for LBP...... and significant relationships between radiological findings and subjective symptoms have both been notoriously difficult to identify. The lack of consensus on clinical criteria and radiological definitions has hampered the undertaking of properly executed epidemiological studies. The natural history of LBP...

  14. Quantum degenerate systems

    Energy Technology Data Exchange (ETDEWEB)

    Micheli, Fiorenza de [Centro de Estudios Cientificos, Arturo Prat 514, Valdivia (Chile); Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Casilla 4059, Valparaiso (Chile); Zanelli, Jorge [Centro de Estudios Cientificos, Arturo Prat 514, Valdivia (Chile); Universidad Andres Bello, Av. Republica 440, Santiago (Chile)

    2012-10-15

    A degenerate dynamical system is characterized by a symplectic structure whose rank is not constant throughout phase space. Its phase space is divided into causally disconnected, nonoverlapping regions in each of which the rank of the symplectic matrix is constant, and there are no classical orbits connecting two different regions. Here the question of whether this classical disconnectedness survives quantization is addressed. Our conclusion is that in irreducible degenerate systems-in which the degeneracy cannot be eliminated by redefining variables in the action-the disconnectedness is maintained in the quantum theory: there is no quantum tunnelling across degeneracy surfaces. This shows that the degeneracy surfaces are boundaries separating distinct physical systems, not only classically, but in the quantum realm as well. The relevance of this feature for gravitation and Chern-Simons theories in higher dimensions cannot be overstated.

  15. Laenderyggens degeneration og radiologi

    DEFF Research Database (Denmark)

    Jacobsen, Steffen; Gosvig, Kasper Kjaerulf; Sonne-Holm, Stig

    2006-01-01

    and significant relationships between radiological findings and subjective symptoms have both been notoriously difficult to identify. The lack of consensus on clinical criteria and radiological definitions has hampered the undertaking of properly executed epidemiological studies. The natural history of LBP...... is cyclic: exacerbations relieved by asymptomatic periods. New imaging modalities, including the combination of MR imaging and multiplanar 3-D CT scans, have broadened our awareness of possible pain-generating degenerative processes of the lumbar spine other than disc degeneration....

  16. Active Segmentation.

    Science.gov (United States)

    Mishra, Ajay; Aloimonos, Yiannis

    2009-01-01

    The human visual system observes and understands a scene/image by making a series of fixations. Every fixation point lies inside a particular region of arbitrary shape and size in the scene which can either be an object or just a part of it. We define as a basic segmentation problem the task of segmenting that region containing the fixation point. Segmenting the region containing the fixation is equivalent to finding the enclosing contour- a connected set of boundary edge fragments in the edge map of the scene - around the fixation. This enclosing contour should be a depth boundary.We present here a novel algorithm that finds this bounding contour and achieves the segmentation of one object, given the fixation. The proposed segmentation framework combines monocular cues (color/intensity/texture) with stereo and/or motion, in a cue independent manner. The semantic robots of the immediate future will be able to use this algorithm to automatically find objects in any environment. The capability of automatically segmenting objects in their visual field can bring the visual processing to the next level. Our approach is different from current approaches. While existing work attempts to segment the whole scene at once into many areas, we segment only one image region, specifically the one containing the fixation point. Experiments with real imagery collected by our active robot and from the known databases 1 demonstrate the promise of the approach.

  17. Apparatus For Laminating Segmented Core For Electric Machine

    Science.gov (United States)

    Lawrence, Robert Anthony; Stabel, Gerald R

    2003-06-17

    A segmented core for an electric machine includes segments stamped from coated electric steel. The segments each have a first end, a second end, and winding openings. A predetermined number of segments are placed end-to-end to form layers. The layers are stacked such that each of the layers is staggered from adjacent layers by a predetermined rotation angle. The winding openings of each of the layers are in vertical alignment with the winding openings of the adjacent layers. The stack of layers is secured to form the segmented core.

  18. Degenerate band edge laser

    Science.gov (United States)

    Veysi, Mehdi; Othman, Mohamed A. K.; Figotin, Alexander; Capolino, Filippo

    2018-05-01

    We propose a class of lasers based on a fourth-order exceptional point of degeneracy (EPD) referred to as the degenerate band edge (DBE). EPDs have been found in parity-time-symmetric photonic structures that require loss and/or gain; here we show that the DBE is a different kind of EPD since it occurs in periodic structures that are lossless and gainless. Because of this property, a small level of gain is sufficient to induce single-frequency lasing based on a synchronous operation of four degenerate Floquet-Bloch eigenwaves. This lasing scheme constitutes a light-matter interaction mechanism that leads also to a unique scaling law of the laser threshold with the inverse of the fifth power of the laser-cavity length. The DBE laser has the lowest lasing threshold in comparison to a regular band edge laser and to a conventional laser in cavities with the same loaded quality (Q ) factor and length. In particular, even without mirror reflectors the DBE laser exhibits a lasing threshold which is an order of magnitude lower than that of a uniform cavity laser of the same length and with very high mirror reflectivity. Importantly, this novel DBE lasing regime enforces mode selectivity and coherent single-frequency operation even for pumping rates well beyond the lasing threshold, in contrast to the multifrequency nature of conventional uniform cavity lasers.

  19. Segmentation: Identification of consumer segments

    DEFF Research Database (Denmark)

    Høg, Esben

    2005-01-01

    It is very common to categorise people, especially in the advertising business. Also traditional marketing theory has taken in consumer segments as a favorite topic. Segmentation is closely related to the broader concept of classification. From a historical point of view, classification has its...... origin in other sciences as for example biology, anthropology etc. From an economic point of view, it is called segmentation when specific scientific techniques are used to classify consumers to different characteristic groupings. What is the purpose of segmentation? For example, to be able to obtain...... a basic understanding of grouping people. Advertising agencies may use segmentation totarget advertisements, while food companies may usesegmentation to develop products to various groups of consumers. MAPP has for example investigated the positioning of fish in relation to other food products...

  20. Segmental Vitiligo.

    Science.gov (United States)

    van Geel, Nanja; Speeckaert, Reinhart

    2017-04-01

    Segmental vitiligo is characterized by its early onset, rapid stabilization, and unilateral distribution. Recent evidence suggests that segmental and nonsegmental vitiligo could represent variants of the same disease spectrum. Observational studies with respect to its distribution pattern point to a possible role of cutaneous mosaicism, whereas the original stated dermatomal distribution seems to be a misnomer. Although the exact pathogenic mechanism behind the melanocyte destruction is still unknown, increasing evidence has been published on the autoimmune/inflammatory theory of segmental vitiligo. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. 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

  2. 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

  3. Second order degenerate elliptic equations

    International Nuclear Information System (INIS)

    Duong Minh Duc.

    1988-08-01

    Using an improved Sobolev inequality we study a class of elliptic operators which is degenerate inside the domain and strongly degenerate near the boundary of the domain. Our results are applicable to the L 2 -boundary value problem and the mixed boundary problem. (author). 18 refs

  4. Double Degenerate Stars

    International Nuclear Information System (INIS)

    Xin-Lian, Luo; Hua, Bai; Lei, Zhao

    2008-01-01

    Regardless of the formation mechanism, an exotic object, the double degenerate star (DDS), is introduced and investigated, which is composed of baryonic matter and some unknown fermion dark matter. Different from the simple white dwarfs (WDs), there is additional gravitational force provided by the unknown fermion component inside DDSs, which may strongly affect the structure and the stability of such kind of objects. Many possible and strange observational phenomena connecting with them are concisely discussed. Similar to the normal WD, this object can also experience thermonuclear explosion as type Ia supernova explosion when DDS's mass exceeds the maximum mass that can be supported by electron degeneracy pressure. However, since the total mass of baryonic matter can be much lower than that of WD at Chandrasekhar mass limit, the peak luminosity should be much dimmer than what we expect before, which may throw a slight shadow on the standard candle of SN Ia in the research of cosmology. (general)

  5. Percutaneous full endoscopic lumbar foraminoplasty for adjacent level foraminal stenosis following vertebral intersegmental fusion in an awake and aware patient under local anesthesia: A case report.

    Science.gov (United States)

    Yamashita, Kazuta; Higashino, Kosaku; Sakai, Toshinori; Takata, Yoichiro; Hayashi, Fumio; Tezuka, Fumitake; Morimoto, Masatoshi; Chikawa, Takashi; Nagamachi, Akihiro; Sairyo, Koichi

    2017-01-01

    Percutaneous endoscopic surgery for the lumbar spine has become established in the last decade. It requires only an 8 mm skin incision, causes minimal damage to the paravertebral muscles, and can be performed under local anesthesia. With the advent of improved equipment, in particular the high-speed surgical drill, the indications for percutaneous endoscopic surgery have expanded to include lumbar spinal canal stenosis. Transforaminal percutaneous endoscopic discectomy has been used to treat intervertebral stenosis. However, it has been reported that adjacent level disc degeneration and foraminal stenosis can occur following intervertebral segmental fusion. When this adjacent level pathology becomes symptomatic, additional fusion surgery is often needed. We performed minimally invasive percutaneous full endoscopic lumbar foraminoplasty in an awake and aware 50-year-old woman under local anesthesia. The procedure was successful with no complications. Her radiculopathy, including muscle weakness and leg pain due to impingement of the exiting nerve, improved after the surgery. J. Med. Invest. 64: 291-295, August, 2017.

  6. [Lattice degeneration of the retina].

    Science.gov (United States)

    Boĭko, E V; Suetov, A A; Mal'tsev, D S

    2014-01-01

    Lattice degeneration of the retina is a clinically important type of peripheral retinal dystrophies due to its participation in the pathogenesis of rhegmatogenous retinal detachment. In spite of extensive epidemiological, morphological, and clinical data, the question on causes of this particular type of retinal dystrophies currently remains debatable. Existing hypotheses on pathogenesis of retinal structural changes in lattice degeneration explain it to a certain extent. In clinical ophthalmology it is necessary to pay close attention to this kind of degenerations and distinguish between cases requiring preventive treatment and those requiring monitoring.

  7. Macular degeneration - age-related

    Science.gov (United States)

    ... AMD occurs when the blood vessels under the macula become thin and brittle. Small yellow deposits, called drusen, form. Almost all people with macular degeneration start with the dry form. Wet AMD occurs ...

  8. Computed tomography of Wallerian degeneration

    International Nuclear Information System (INIS)

    Uchino, Akira; Maeda, Fumihiko

    1986-01-01

    CT findings of wallerian degeneration of the pyramidal tract at the midbrain (atrophy of cerebral peduncle following cerebrovascular accident) were studied in 34 patients (44 CT scans) with old cerebrovascular accidents. Severe atrophy of cerebral peduncle was noted when the ipsilateral motor cortex was involved. However, when the posterior limb of the internal capsule was involved, atrophy of the ipsilateral cerebral peduncle was mild. In this series, the shortest interval between cerebrovascular accident and wallerian degeneration was 8 month. (author)

  9. Skew-adjacency matrices of graphs

    NARCIS (Netherlands)

    Cavers, M.; Cioaba, S.M.; Fallat, S.; Gregory, D.A.; Haemers, W.H.; Kirkland, S.J.; McDonald, J.J.; Tsatsomeros, M.

    2012-01-01

    The spectra of the skew-adjacency matrices of a graph are considered as a possible way to distinguish adjacency cospectral graphs. This leads to the following topics: graphs whose skew-adjacency matrices are all cospectral; relations between the matchings polynomial of a graph and the characteristic

  10. Mixed segmentation

    DEFF Research Database (Denmark)

    Hansen, Allan Grutt; Bonde, Anders; Aagaard, Morten

    content analysis and audience segmentation in a single-source perspective. The aim is to explain and understand target groups in relation to, on the one hand, emotional response to commercials or other forms of audio-visual communication and, on the other hand, living preferences and personality traits...

  11. What Is Age-Related Macular Degeneration?

    Science.gov (United States)

    ... Eye Health / Eye Health A-Z Age-Related Macular Degeneration Sections What Is Macular Degeneration? How is AMD ... What Does Macular Degeneration Look Like? What Is Macular Degeneration? Leer en Español: ¿Qué es la degeneración macular ...

  12. Adjacent Lumbar Disc Herniation after Lumbar Short Spinal Fusion

    OpenAIRE

    Ninomiya, Koshi; Iwatsuki, Koichi; Ohnishi, Yu-ichiro; Ohkawa, Toshika; Yoshimine, Toshiki

    2014-01-01

    A 70-year-old outpatient presented with a chief complaint of sudden left leg motor weakness and sensory disturbance. He had undergone L4/5 posterior interbody fusion with L3–5 posterior fusions for spondylolisthesis 3 years prior, and the screws were removed 1 year later. He has been followed up for 3 years, and there had been no adjacent segment problems before this presentation. Lumbar magnetic resonance imaging (MRI) showed a large L2/3 disc hernia descending to the L3/4 level. Compared to...

  13. IMMEDIATE RECIPROCAL CHANGES AT ADJACENT LEVEL FOLLOWING SINGLE-LEVEL ALIF

    OpenAIRE

    Uribe, Enrique Vargas; Amaral, Rodrigo; Marchi, Luis; Jensen, Rubens; Oliveira, Leonardo; Fortti, Fernanda; Coutinho, Etevaldo; Pimenta, Luiz

    2015-01-01

    Objective : To assess the segmental sagittal parameters and the adjacent mobile segment after interbody fusion by anterior approach in single-level L5-S1. Methods : Retrospective study. Inclusion: Interbody fusion by anterior approach (10°/15° angle), due to DDD, low-grade spondylolisthesis and/or stenosis without prior lumbar fusion. Thirty-five cases were included (25 women; mean age 47±15 years). Analysis of lumbar radiographs were performed preoperatively and 3 months after surgery. The ...

  14. Laser Truss Sensor for Segmented Telescope Phasing

    Science.gov (United States)

    Liu, Duncan T.; Lay, Oliver P.; Azizi, Alireza; Erlig, Herman; Dorsky, Leonard I.; Asbury, Cheryl G.; Zhao, Feng

    2011-01-01

    A paper describes the laser truss sensor (LTS) for detecting piston motion between two adjacent telescope segment edges. LTS is formed by two point-to-point laser metrology gauges in a crossed geometry. A high-resolution (distribution can be optimized using the range-gated metrology (RGM) approach.

  15. Retina image–based optic disc segmentation

    Directory of Open Access Journals (Sweden)

    Ching-Lin Wang

    2016-05-01

    Full Text Available The change of optic disc can be used to diagnose many eye diseases, such as glaucoma, diabetic retinopathy and macular degeneration. Moreover, retinal blood vessel pattern is unique for human beings even for identical twins. It is a highly stable pattern in biometric identification. Since optic disc is the beginning of the optic nerve and main blood vessels in retina, it can be used as a reference point of identification. Therefore, optic disc segmentation is an important technique for developing a human identity recognition system and eye disease diagnostic system. This article hence presents an optic disc segmentation method to extract the optic disc from a retina image. The experimental results show that the optic disc segmentation method can give impressive results in segmenting the optic disc from a retina image.

  16. Brookhaven segment interconnect

    International Nuclear Information System (INIS)

    Morse, W.M.; Benenson, G.; Leipuner, L.B.

    1983-01-01

    We have performed a high energy physics experiment using a multisegment Brookhaven FASTBUS system. The system was composed of three crate segments and two cable segments. We discuss the segment interconnect module which permits communication between the various segments

  17. Loss of Arf4 causes severe degeneration of the exocrine pancreas but not cystic kidney disease or retinal degeneration.

    Directory of Open Access Journals (Sweden)

    Jillian N Pearring

    2017-04-01

    Full Text Available Arf4 is proposed to be a critical regulator of membrane protein trafficking in early secretory pathway. More recently, Arf4 was also implicated in regulating ciliary trafficking, however, this has not been comprehensively tested in vivo. To directly address Arf4's role in ciliary transport, we deleted Arf4 specifically in either rod photoreceptor cells, kidney, or globally during the early postnatal period. Arf4 deletion in photoreceptors did not cause protein mislocalization or retinal degeneration, as expected if Arf4 played a role in protein transport to the ciliary outer segment. Likewise, Arf4 deletion in kidney did not cause cystic disease, as expected if Arf4 were involved in general ciliary trafficking. In contrast, global Arf4 deletion in the early postnatal period resulted in growth restriction, severe pancreatic degeneration and early death. These findings are consistent with Arf4 playing a critical role in endomembrane trafficking, particularly in the pancreas, but not in ciliary function.

  18. Pregnancy outcome of a patient following myomectomy performed during first trimester for red degeneration of fibroid

    Directory of Open Access Journals (Sweden)

    Asma Habib

    2016-08-01

    Full Text Available Pain due to red degeneration of fibroid during pregnancy is usually associated with large myomas. Necrobiosis / red degeneration typically manifests itself about midpregnancy when Lhe leiomyoma suddenly becomes acutely painful, enlarged and tender. The common differential diagnosis of this condition are torsion of the pedicle of an ovarian cyst/a leiomyoma, abruplion placentae, acute pyelitis or any abdominal catastrophe. Ultrasound can easily delineate the presence of myomas of mixed echogenicity along with pregnancy and clinical findings usually suggest the diagnosis of pregnancy complicated by red degeneration of fibroid. The acute pain usually subsides within 3-10 days of conservative treatment. Only refractory cases (2% of patients may demand surgical intervention in early gestation with the known risk of miscarriage. Here we report a pregnancy managed at 13 weeks by myomectomy for red degeneration. The patient ultimately delivered a healthy female child at 38 weeks by lower segment caesarean section.

  19. Age-Related Macular Degeneration.

    Science.gov (United States)

    Mehta, Sonia

    2015-09-01

    Age-related macular degeneration (AMD) is the leading cause of vision loss in the elderly. AMD is diagnosed based on characteristic retinal findings in individuals older than 50. Early detection and treatment are critical in increasing the likelihood of retaining good and functional vision. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Degenerated differential pair with controllable transconductance

    NARCIS (Netherlands)

    Mensink, Clemens; Mensink, Clemens H.J.; Nauta, Bram

    1998-01-01

    A differential pair with input transistors and provided with a variable degeneration resistor. The degeneration resistor comprises a series arrangement of two branches of coupled resistors which are shunted in mutually corresponding points by respective control transistors whose gates are

  1. MRI histogram analysis enables objective and continuous classification of intervertebral disc degeneration.

    Science.gov (United States)

    Waldenberg, Christian; Hebelka, Hanna; Brisby, Helena; Lagerstrand, Kerstin Magdalena

    2018-05-01

    Magnetic resonance imaging (MRI) is the best diagnostic imaging method for low back pain. However, the technique is currently not utilized in its full capacity, often failing to depict painful intervertebral discs (IVDs), potentially due to the rough degeneration classification system used clinically today. MR image histograms, which reflect the IVD heterogeneity, may offer sensitive imaging biomarkers for IVD degeneration classification. This study investigates the feasibility of using histogram analysis as means of objective and continuous grading of IVD degeneration. Forty-nine IVDs in ten low back pain patients (six males, 25-69 years) were examined with MRI (T2-weighted images and T2-maps). Each IVD was semi-automatically segmented on three mid-sagittal slices. Histogram features of the IVD were extracted from the defined regions of interest and correlated to Pfirrmann grade. Both T2-weighted images and T2-maps displayed similar histogram features. Histograms of well-hydrated IVDs displayed two separate peaks, representing annulus fibrosus and nucleus pulposus. Degenerated IVDs displayed decreased peak separation, where the separation was shown to correlate strongly with Pfirrmann grade (P histogram appearances. Histogram features correlated well with IVD degeneration, suggesting that IVD histogram analysis is a suitable tool for objective and continuous IVD degeneration classification. As histogram analysis revealed IVD heterogeneity, it may be a clinical tool for characterization of regional IVD degeneration effects. To elucidate the usefulness of histogram analysis in patient management, IVD histogram features between asymptomatic and symptomatic individuals needs to be compared.

  2. CERKL knockdown causes retinal degeneration in zebrafish.

    Directory of Open Access Journals (Sweden)

    Marina Riera

    Full Text Available The human CERKL gene is responsible for common and severe forms of retinal dystrophies. Despite intense in vitro studies at the molecular and cellular level and in vivo analyses of the retina of murine knockout models, CERKL function remains unknown. In this study, we aimed to approach the developmental and functional features of cerkl in Danio rerio within an Evo-Devo framework. We show that gene expression increases from early developmental stages until the formation of the retina in the optic cup. Unlike the high mRNA-CERKL isoform multiplicity shown in mammals, the moderate transcriptional complexity in fish facilitates phenotypic studies derived from gene silencing. Moreover, of relevance to pathogenicity, teleost CERKL shares the two main human protein isoforms. Morpholino injection has been used to generate a cerkl knockdown zebrafish model. The morphant phenotype results in abnormal eye development with lamination defects, failure to develop photoreceptor outer segments, increased apoptosis of retinal cells and small eyes. Our data support that zebrafish Cerkl does not interfere with proliferation and neural differentiation during early developmental stages but is relevant for survival and protection of the retinal tissue. Overall, we propose that this zebrafish model is a powerful tool to unveil CERKL contribution to human retinal degeneration.

  3. Light and inherited retinal degeneration

    OpenAIRE

    Paskowitz, D M; LaVail, M M; Duncan, J L

    2006-01-01

    Light deprivation has long been considered a potential treatment for patients with inherited retinal degenerative diseases, but no therapeutic benefit has been demonstrated to date. In the few clinical studies that have addressed this issue, the underlying mutations were unknown. Our rapidly expanding knowledge of the genes and mechanisms involved in retinal degeneration have made it possible to reconsider the potential value of light restriction in specific genetic contexts. This review summ...

  4. A comprehensive segmentation analysis of crude oil market based on time irreversibility

    Science.gov (United States)

    Xia, Jianan; Shang, Pengjian; Lu, Dan; Yin, Yi

    2016-05-01

    In this paper, we perform a comprehensive entropic segmentation analysis of crude oil future prices from 1983 to 2014 which used the Jensen-Shannon divergence as the statistical distance between segments, and analyze the results from original series S and series begin at 1986 (marked as S∗) to find common segments which have same boundaries. Then we apply time irreversibility analysis of each segment to divide all segments into two groups according to their asymmetry degree. Based on the temporal distribution of the common segments and high asymmetry segments, we figure out that these two types of segments appear alternately and do not overlap basically in daily group, while the common portions are also high asymmetry segments in weekly group. In addition, the temporal distribution of the common segments is fairly close to the time of crises, wars or other events, because the hit from severe events to oil price makes these common segments quite different from their adjacent segments. The common segments can be confirmed in daily group series, or weekly group series due to the large divergence between common segments and their neighbors. While the identification of high asymmetry segments is helpful to know the segments which are not affected badly by the events and can recover to steady states automatically. Finally, we rearrange the segments by merging the connected common segments or high asymmetry segments into a segment, and conjoin the connected segments which are neither common nor high asymmetric.

  5. Intervertebral disc (IVD): Structure, degeneration, repair and regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Whatley, Benjamin R.; Wen Xuejun, E-mail: xjwen@clemson.edu

    2012-02-01

    Low back pain affects a large portion of the population, resulting in high care costs for therapy and treatment. One primary cause of low back pain is the degeneration of the intervertebral disc (IVD) resulting in the compression of the spinal nerves and adjacent vertebrae. Exact causes of degeneration are unknown, but it is thought that natural aging, and both biological and genetic factors may play a significant role in the degenerative process. Conventional methods to alleviate low back pain include spinal fusion and artificial disc replacement. Traditional treatments through spinal fusion may eliminate pain yet do not restore disc function and lead to further degeneration of adjacent levels by altering disc biomechanics and natural kinematics. Recently, artificial IVD replacements have started to gain interest, with two IVD implants currently approved in the United States. Although these implants facilitate the preservation of motions and disc space height, they are unable to sustain compressive forces due to their lack of elasticity. In addition, the implants may produce wear debris that can cause osteolysis and other deleterious effects. As an alternative to these conventional approaches, tissue engineered IVD constructs offer the advantage of biointegration while preserving the essential attributes of natural motion and disc space restoration. There is a great need for the development of tissue engineered scaffolds that simulate the natural 3D morphology and microenvironment of the targeted tissue. Scaffolds should facilitate biological transport to satisfy nutrition and waste removal requirements within the IVD. The discrete tissue architectures of the nucleus pulposus (NP) and annulus fibrosus (AF) have posed great challenges to IVD tissue engineering. Current attempts have not been able to satisfy the biological functions and/or mechanical properties of native tissue. Therefore, these current scaffolds are far from satisfactory. This review highlights the

  6. Association of age-related macular degeneration and reticular macular disease with cardiovascular disease.

    Science.gov (United States)

    Rastogi, Neelesh; Smith, R Theodore

    2016-01-01

    Age-related macular degeneration is the leading cause of adult blindness in the developed world. Thus, major endeavors to understand the risk factors and pathogenesis of this disease have been undertaken. Reticular macular disease is a proposed subtype of age-related macular degeneration correlating histologically with subretinal drusenoid deposits located between the retinal pigment epithelium and the inner segment ellipsoid zone. Reticular lesions are more prevalent in females and in older age groups and are associated with a higher mortality rate. Risk factors for developing age-related macular degeneration include hypertension, smoking, and angina. Several genes related to increased risk for age-related macular degeneration and reticular macular disease are also associated with cardiovascular disease. Better understanding of the clinical and genetic risk factors for age-related macular degeneration and reticular macular disease has led to the hypothesis that these eye diseases are systemic. A systemic origin may help to explain why reticular disease is diagnosed more frequently in females as males suffer cardiovascular mortality at an earlier age, before the age of diagnosis of reticular macular disease and age-related macular degeneration. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Histopathological effects of intraoperative radiotherapy on pancreas and adjacent tissues: a postmortem analysis

    International Nuclear Information System (INIS)

    Hoekstra, H.J.; Restrepo, C.; Kinsella, T.J.; Sindelar, W.F.

    1988-01-01

    Intraoperative radiotherapy (IORT) has been utilized in the treatment of resectable and unresectable pancreatic carcinoma at the National Cancer Institute. Detailed autopsy analyses of the radiation effects on the pancreas and adjacent tissues were performed on 13 patients dying at various times following therapy. IORT can induce a progressive retroperitoneal fibrosis and fibrosis of the porta hepatis in patients with resectable pancreatic carcinoma. In unresectable pancreatic carcinoma, the major expression of intraoperative irradiation with external beam irradiation is a progressive fibrosis of the pancreas with vascular sclerosis, nerve degeneration, atrophy of acinar cells, and atypical changes in the ducts of the pancreas, as well as degenerative changes of the pancreatic tumor

  8. Lattice degeneration of the retina.

    Science.gov (United States)

    Byer, N E

    1979-01-01

    Lattice degeneration of the retina is the most important of all clinically distinct entities that effect the peripheral fundus and are related to retinal detachment. The purpose of this review is to survey the extensive literature, to evaluate the many diverse opinions on this subject, and to correlate and summarize all the known facts regarding this disease entity. The disease is fully defined and described, both clinically and histologically. Some aspects of the disease are still poorly understood, and some remain controversial, especially in the area of management. For this reason, the indications for treatment are discussed under eight subsections, with a view toward providing practical guidelines for recommendations in management.

  9. Age-related macular degeneration

    DEFF Research Database (Denmark)

    la Cour, Morten; Kiilgaard, Jens Folke; Nissen, Mogens Holst

    2002-01-01

    Age-related macular degeneration (AMD) is a common macular disease affecting elderly people in the Western world. It is characterised by the appearance of drusen in the macula, accompanied by choroidal neovascularisation (CNV) or geographic atrophy. The disease is more common in Caucasian....... Smoking is probably also a risk factor. Preventive strategies using macular laser photocoagulation are under investigation, but their efficacy in preventing visual loss is as yet unproven. There is no treatment with proven efficacy for geographic atrophy. Optimal treatment for exudative AMD requires...

  10. Target migration from re-inflation of adjacent atelectasis during lung stereotactic body radiotherapy.

    Science.gov (United States)

    Mao, Bijing; Verma, Vivek; Zheng, Dandan; Zhu, Xiaofeng; Bennion, Nathan R; Bhirud, Abhijeet R; Poole, Maria A; Zhen, Weining

    2017-06-10

    Stereotactic body radiotherapy (SBRT) is a widely accepted option for the treatment of medically inoperable early-stage non-small cell lung cancer (NSCLC). Herein, we highlight the importance of interfraction image guidance during SBRT. We describe a case of early-stage NSCLC associated with segmental atelectasis that translocated 15 mm anteroinferiorly due to re-expansion of the adjacent segmental atelectasis following the first fraction. The case exemplifies the importance of cross-sectional image-guided radiotherapy that shows the intended target, as opposed to aligning based on rigid anatomy alone, especially in cases associated with potentially "volatile" anatomic areas.

  11. Outer segment phagocytosis by cultured retinal pigment epithelial cells requires Gas6.

    Science.gov (United States)

    Hall, M O; Prieto, A L; Obin, M S; Abrams, T A; Burgess, B L; Heeb, M J; Agnew, B J

    2001-10-01

    The function and viability of vertebrate photoreceptors requires the daily phagocytosis of photoreceptor outer segments (OS) by the adjacent retinal pigment epithelium (RPE). We demonstrate here a critical role in this process for Gas6 and by implication one of its receptor protein tyrosine kinases (RTKs), Mertk (Mer). Gas6 specifically and selectively stimulates the phagocytosis of OS by normal cultured rat RPE cells. The magnitude of the response is dose-dependent and shows an absolute requirement for calcium. By contrast the Royal College of Surgeons (RCS) rat RPE cells, in which a mutation in the gene Mertk results in the expression of a truncated, non-functional receptor, does not respond to Gas6. These data strongly suggest that activation of Mertk by its ligand, Gas6, is the specific signaling pathway responsible for initiating the ingestion of shed OS. Moreover, photoreceptor degeneration in the RCS rat retina, which lacks Mertk, and in humans with a mutation in Mertk, strongly suggests that the Gas6/Mertk signaling pathway is essential for photoreceptor viability. We believe that this is the first demonstration of a specific function for Gas6 in the eye. Copyright 2001 Academic Press.

  12. Multiple sclerosis and anterograde axonal degeneration study by magnetic resonance

    International Nuclear Information System (INIS)

    Martinez Pardo, P.; Capdevila Cirera, A.; Sanz Marin, P.M.; Gili Planas, J.

    1993-01-01

    Multiple sclerosis (MS) is a disease of the central nervous system that affects specifically the myelin. Its diagnosis by imaging techniques is, since the development of magnetic resonance (MR), relatively simple, and its occasional association with anterograde axonal degeneration (WD) has been reported. In both disorders, there is a lengthening of the T1 and T2 relaxation times. In the present report, 76 patients with MS with less than 4 plaques in the typical periventricular position were studied retrospectively, resulting in a rate of association with anterograde axonal degeneration of 8%. We consider that in spite of their same behavior in MR,MS and WD, with moreover represent completely different pathologies, are perfectly differential by MR. The S-E images with longer repetition and echo times in the axial and coronal planes have proved to be those most sensitive for this differentiation. Given that MS is specific pathology of then myelin, the axonal damages in delayed until several plaques adjacent to an axon affect it. We consider that this, added to the restriction of our study group (less than 4 plaques), is the cause of the pow percentage of the MS-WD association in our study. (Author)

  13. Genetics of Frontotemporal Lobar Degeneration

    Directory of Open Access Journals (Sweden)

    Daniela eGalimberti

    2012-04-01

    Full Text Available Frontotemporal Lobar Degeneration (FTLD is the most frequent neurodegenerative disorder with a presenile onset. It presents with a spectrum of clinical manifestations, ranging from behavioural and executive impairment to language disorders and motor dysfunction. Familial aggregation is frequently reported in FTLD, and about 10% of cases have an autosomal dominant transmission. Microtubule Associated Protein Tau gene (MAPT mutations have been the first ones identified and are generally associated with early onset behavioural variant Frontotemporal Dementia (bvFTD phenotype. More recently, progranulin gene (GRN mutations were recognized in association with familial form of FTLD. In addition, other genes are linked to rare cases of familial FTLD. Lastly, a number of genetic risk factors for sporadic forms have also been identified.

  14. Frontotemporal Degeneration in a Child.

    Science.gov (United States)

    Terrill, Tyler; Pascual, Juan M

    2017-07-01

    There is a predilection for the frontal and temporal lobes in certain cases of dementia in the adult, leading to the syndrome of frontotemporal dementia. However, this syndrome has seemed to elude the developing brain until now. We describe an example of apparently selective neurodegeneration of the frontal and temporal regions during development associated with some of the clinical, magnetic resonance imaging, and fludeoxyglucose positron emission tomography (FDG PET) scan features of canonical frontotemporal dementia in the adult. This patient does not have any of the common frontotemporal dementia-causing mutations or known progressive brain disorders of children. This patient illustrates that symptomatic, selective, and progressive vulnerability of the frontal and temporal lobes is not restricted to adulthood, expanding the phenotype of frontotemporal degeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Naturalness of nearly degenerate neutrinos

    International Nuclear Information System (INIS)

    Casas, J.A.; Espinosa, J.R.; Ibarra, A.; Navarro, I.

    1999-01-01

    If neutrinos are to play a relevant cosmological role, they must be essentially degenerate. We study whether radiative corrections can or cannot be responsible for the small mass splittings, in agreement with all the available experimental data. We perform an exhaustive exploration of the bimaximal mixing scenario, finding that (i) the vacuum oscillations solution to the solar neutrino problem is always excluded; (ii) if the mass matrix is produced by a see-saw mechanism, there are large regions of the parameter space consistent with the large angle MSW solution, providing a natural origin for the Δm sol 2 atm 2 hierarchy; (iii) the bimaximal structure becomes then stable under radiative corrections. We also provide analytical expressions for the mass splittings and mixing angles and present a particularly simple see-saw ansatz consistent with all observations

  16. Eigenstate Thermalization for Degenerate Observables

    Science.gov (United States)

    Anza, Fabio; Gogolin, Christian; Huber, Marcus

    2018-04-01

    Under unitary time evolution, expectation values of physically reasonable observables often evolve towards the predictions of equilibrium statistical mechanics. The eigenstate thermalization hypothesis (ETH) states that this is also true already for individual energy eigenstates. Here we aim at elucidating the emergence of the ETH for observables that can realistically be measured due to their high degeneracy, such as local, extensive, or macroscopic observables. We bisect this problem into two parts, a condition on the relative overlaps and one on the relative phases between the eigenbases of the observable and Hamiltonian. We show that the relative overlaps are unbiased for highly degenerate observables and demonstrate that unless relative phases conspire to cumulative effects, this makes such observables verify the ETH. Through this we elucidate potential pathways towards proofs of thermalization.

  17. Automatic lung segmentation in the presence of alveolar collapse

    Directory of Open Access Journals (Sweden)

    Noshadi Areg

    2017-09-01

    Full Text Available Lung ventilation and perfusion analyses using chest imaging methods require a correct segmentation of the lung to offer anatomical landmarks for the physiological data. An automatic segmentation approach simplifies and accelerates the analysis. However, the segmentation of the lungs has shown to be difficult if collapsed areas are present that tend to share similar gray values with surrounding non-pulmonary tissue. Our goal was to develop an automatic segmentation algorithm that is able to approximate dorsal lung boundaries even if alveolar collapse is present in the dependent lung areas adjacent to the pleura. Computed tomography data acquired in five supine pigs with injured lungs were used for this purpose. First, healthy lung tissue was segmented using a standard 3D region growing algorithm. Further, the bones in the chest wall surrounding the lungs were segmented to find the contact points of ribs and pleura. Artificial boundaries of the dorsal lung were set by spline interpolation through these contact points. Segmentation masks of the entire lung including the collapsed regions were created by combining the splines with the segmentation masks of the healthy lung tissue through multiple morphological operations. The automatically segmented images were then evaluated by comparing them to manual segmentations and determining the Dice similarity coefficients (DSC as a similarity measure. The developed method was able to accurately segment the lungs including the collapsed regions (DSCs over 0.96.

  18. Time-constrained project scheduling with adjacent resources

    NARCIS (Netherlands)

    Hurink, Johann L.; Kok, A.L.; Paulus, J.J.; Schutten, Johannes M.J.

    We develop a decomposition method for the Time-Constrained Project Scheduling Problem (TCPSP) with adjacent resources. For adjacent resources the resource units are ordered and the units assigned to a job have to be adjacent. On top of that, adjacent resources are not required by single jobs, but by

  19. Time-constrained project scheduling with adjacent resources

    NARCIS (Netherlands)

    Hurink, Johann L.; Kok, A.L.; Paulus, J.J.; Schutten, Johannes M.J.

    2008-01-01

    We develop a decomposition method for the Time-Constrained Project Scheduling Problem (TCPSP) with Adjacent Resources. For adjacent resources the resource units are ordered and the units assigned to a job have to be adjacent. On top of that, adjacent resources are not required by single jobs, but by

  20. Dual Contrast CT Method Enables Diagnostics of Cartilage Injuries and Degeneration Using a Single CT Image.

    Science.gov (United States)

    Saukko, Annina E A; Honkanen, Juuso T J; Xu, Wujun; Väänänen, Sami P; Jurvelin, Jukka S; Lehto, Vesa-Pekka; Töyräs, Juha

    2017-12-01

    Cartilage injuries may be detected using contrast-enhanced computed tomography (CECT) by observing variations in distribution of anionic contrast agent within cartilage. Currently, clinical CECT enables detection of injuries and related post-traumatic degeneration based on two subsequent CT scans. The first scan allows segmentation of articular surfaces and lesions while the latter scan allows evaluation of tissue properties. Segmentation of articular surfaces from the latter scan is difficult since the contrast agent diffusion diminishes the image contrast at surfaces. We hypothesize that this can be overcome by mixing anionic contrast agent (ioxaglate) with bismuth oxide nanoparticles (BINPs) too large to diffuse into cartilage, inducing a high contrast at the surfaces. Here, a dual contrast method employing this mixture is evaluated by determining the depth-wise X-ray attenuation profiles in intact, enzymatically degraded, and mechanically injured osteochondral samples (n = 3 × 10) using a microCT immediately and at 45 min after immersion in contrast agent. BiNPs were unable to diffuse into cartilage, producing high contrast at articular surfaces. Ioxaglate enabled the detection of enzymatic and mechanical degeneration. In conclusion, the dual contrast method allowed detection of injuries and degeneration simultaneously with accurate cartilage segmentation using a single scan conducted at 45 min after contrast agent administration.

  1. Segmented trapped vortex cavity

    Science.gov (United States)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  2. Pavement management segment consolidation

    Science.gov (United States)

    1998-01-01

    Dividing roads into "homogeneous" segments has been a major problem for all areas of highway engineering. SDDOT uses Deighton Associates Limited software, dTIMS, to analyze life-cycle costs for various rehabilitation strategies on each segment of roa...

  3. Muscle gap approach under a minimally invasive channel technique for treating long segmental lumbar spinal stenosis: A retrospective study.

    Science.gov (United States)

    Bin, Yang; De Cheng, Wang; Wei, Wang Zong; Hui, Li

    2017-08-01

    This study aimed to compare the efficacy of muscle gap approach under a minimally invasive channel surgical technique with the traditional median approach.In the Orthopedics Department of Traditional Chinese and Western Medicine Hospital, Tongzhou District, Beijing, 68 cases of lumbar spinal canal stenosis underwent surgery using the muscle gap approach under a minimally invasive channel technique and a median approach between September 2013 and February 2016. Both approaches adopted lumbar spinal canal decompression, intervertebral disk removal, cage implantation, and pedicle screw fixation. The operation time, bleeding volume, postoperative drainage volume, and preoperative and postoperative visual analog scale (VAS) score and Japanese Orthopedics Association score (JOA) were compared between the 2 groups.All patients were followed up for more than 1 year. No significant difference between the 2 groups was found with respect to age, gender, surgical segments. No diversity was noted in the operation time, intraoperative bleeding volume, preoperative and 1 month after the operation VAS score, preoperative and 1 month after the operation JOA score, and 6 months after the operation JOA score between 2 groups (P > .05). The amount of postoperative wound drainage (260.90 ± 160 mL vs 447.80 ± 183.60 mL, P gap approach group than in the median approach group (P gap approach under a minimally invasive channel group, the average drainage volume was reduced by 187 mL, and the average VAS score 6 months after the operation was reduced by an average of 0.48.The muscle gap approach under a minimally invasive channel technique is a feasible method to treat long segmental lumbar spinal canal stenosis. It retains the integrity of the posterior spine complex to the greatest extent, so as to reduce the adjacent spinal segmental degeneration and soft tissue trauma. Satisfactory short-term and long-term clinical results were obtained.

  4. Imaging geographic atrophy in age-related macular degeneration.

    Science.gov (United States)

    Göbel, Arno P; Fleckenstein, Monika; Schmitz-Valckenberg, Steffen; Brinkmann, Christian K; Holz, Frank G

    2011-01-01

    Advances in retinal imaging technology have largely contributed to the understanding of the natural history, prognostic markers and disease mechanisms of geographic atrophy (GA) due to age-related macular degeneration. There is still no therapy available to halt or slow the disease process. In order to evaluate potential therapeutic effects in interventional trials, there is a need for precise quantification of the GA progression rate. Fundus autofluorescence imaging allows for accurate identification and segmentation of atrophic areas and currently represents the gold standard for evaluating progressive GA enlargement. By means of high-resolution spectral-domain optical coherence tomography, distinct microstructural alterations related to GA can be visualized. Copyright © 2011 S. Karger AG, Basel.

  5. Frontotemporal lobar degeneration: current perspectives

    Directory of Open Access Journals (Sweden)

    Riedl L

    2014-02-01

    Full Text Available Lina Riedl,1 Ian R Mackenzie,2 Hans Förstl,1 Alexander Kurz,1 Janine Diehl-Schmid1 1Center for Cognitive Disorders, Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; 2Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada Abstract: The term frontotemporal lobar degeneration (FTLD refers to a group of progressive brain diseases, which preferentially involve the frontal and temporal lobes. Depending on the primary site of atrophy, the clinical manifestation is dominated by behavior alterations or impairment of language. The onset of symptoms usually occurs before the age of 60 years, and the mean survival from diagnosis varies between 3 and 10 years. The prevalence is estimated at 15 per 100,000 in the population aged between 45 and 65 years, which is similar to the prevalence of Alzheimer's disease in this age group. There are two major clinical subtypes, behavioral-variant frontotemporal dementia and primary progressive aphasia. The neuropathology underlying the clinical syndromes is also heterogeneous. A common feature is the accumulation of certain neuronal proteins. Of these, the microtubule-associated protein tau (MAPT, the transactive response DNA-binding protein, and the fused in sarcoma protein are most important. Approximately 10% to 30% of FTLD shows an autosomal dominant pattern of inheritance, with mutations in the genes for MAPT, progranulin (GRN, and in the chromosome 9 open reading frame 72 (C9orf72 accounting for more than 80% of familial cases. Although significant advances have been made in recent years regarding diagnostic criteria, clinical assessment instruments, neuropsychological tests, cerebrospinal fluid biomarkers, and brain imaging techniques, the clinical diagnosis remains a challenge. To date, there is no specific pharmacological treatment for FTLD. Some evidence has been provided for serotonin reuptake

  6. Speaker segmentation and clustering

    OpenAIRE

    Kotti, M; Moschou, V; Kotropoulos, C

    2008-01-01

    07.08.13 KB. Ok to add the accepted version to Spiral, Elsevier says ok whlile mandate not enforced. This survey focuses on two challenging speech processing topics, namely: speaker segmentation and speaker clustering. Speaker segmentation aims at finding speaker change points in an audio stream, whereas speaker clustering aims at grouping speech segments based on speaker characteristics. Model-based, metric-based, and hybrid speaker segmentation algorithms are reviewed. Concerning speaker...

  7. Spinal segmental dysgenesis

    Directory of Open Access Journals (Sweden)

    N Mahomed

    2009-06-01

    Full Text Available Spinal segmental dysgenesis is a rare congenital spinal abnormality , seen in neonates and infants in which a segment of the spine and spinal cord fails to develop normally . The condition is segmental with normal vertebrae above and below the malformation. This condition is commonly associated with various abnormalities that affect the heart, genitourinary, gastrointestinal tract and skeletal system. We report two cases of spinal segmental dysgenesis and the associated abnormalities.

  8. Paranode Abnormalities and Oxidative Stress in Optic Nerve Vulnerable to Secondary Degeneration: Modulation by 670 nm Light Treatment.

    Directory of Open Access Journals (Sweden)

    Charis R Szymanski

    Full Text Available Secondary degeneration of nerve tissue adjacent to a traumatic injury results in further loss of neurons, glia and function, via mechanisms that may involve oxidative stress. However, changes in indicators of oxidative stress have not yet been demonstrated in oligodendrocytes vulnerable to secondary degeneration in vivo. We show increases in the oxidative stress indicator carboxymethyl lysine at days 1 and 3 after injury in oligodendrocytes vulnerable to secondary degeneration. Dihydroethidium staining for superoxide is reduced, indicating endogenous control of this particular reactive species after injury. Concurrently, node of Ranvier/paranode complexes are altered, with significant lengthening of the paranodal gap and paranode as well as paranode disorganisation. Therapeutic administration of 670 nm light is thought to improve oxidative metabolism via mechanisms that may include increased activity of cytochrome c oxidase. Here, we show that light at 670 nm, delivered for 30 minutes per day, results in in vivo increases in cytochrome c oxidase activity co-localised with oligodendrocytes. Short term (1 day 670 nm light treatment is associated with reductions in reactive species at the injury site. In optic nerve vulnerable to secondary degeneration superoxide in oligodendrocytes is reduced relative to handling controls, and is associated with reduced paranode abnormalities. Long term (3 month administration of 670 nm light preserves retinal ganglion cells vulnerable to secondary degeneration and maintains visual function, as assessed by the optokinetic nystagmus visual reflex. Light at a wavelength of 670 nm may serve as a therapeutic intervention for treatment of secondary degeneration following neurotrauma.

  9. Disk degeneration in 14 year old children

    International Nuclear Information System (INIS)

    Erkintalo, M.; Salminen, J.J.; Paajanen, H.; Terho, P.; Kormano, M.

    1989-01-01

    This paper reports low back symptoms of 1,500 school children (14 years old) evaluated with a questionnaire and with a standardized clinical examination. Forty children who complained of recurrent and/or persistent low back pain and 40 matching symptomless controls were randomly chosen to undergo MR imaging of the lumbar spine. Premature disk degeneration was seen in 25.5% of asymptomatic children and in 40% of those with low back pain. The difference was statistically not significant. Disk degeneration is a surprisingly frequent MR finding in symptomless children. Premature disk degeneration may be the cause of low back pain in some children but is not always symptomatic in childhood

  10. Total absorption by degenerate critical coupling

    Energy Technology Data Exchange (ETDEWEB)

    Piper, Jessica R., E-mail: jrylan@stanford.edu; Liu, Victor; Fan, Shanhui, E-mail: shanhui@stanford.edu [Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2014-06-23

    We consider a mirror-symmetric resonator with two ports. We show that, when excited from a single port, complete absorption can be achieved through critical coupling to degenerate resonances with opposite symmetry. Moreover, any time two resonances with opposite symmetry are degenerate in frequency and absorption is always significantly enhanced. In contrast, when two resonances with the same symmetry are nearly degenerate, there is no absorption enhancement. We numerically demonstrate these effects using a graphene monolayer on top of a photonic crystal slab, illuminated from a single side in the near-infrared.

  11. Automatic Melody Segmentation

    NARCIS (Netherlands)

    Rodríguez López, Marcelo

    2016-01-01

    The work presented in this dissertation investigates music segmentation. In the field of Musicology, segmentation refers to a score analysis technique, whereby notated pieces or passages of these pieces are divided into “units” referred to as sections, periods, phrases, and so on. Segmentation

  12. Age-related macular degeneration: prevention and treatment. A review

    Directory of Open Access Journals (Sweden)

    K. A. Mirzabekova

    2014-07-01

    Full Text Available Age-related macular degeneration (AMD is a multifactorial disease. Age, light exposure, smoking, melanin levels and low-antioxidant diet are contributed to AMD development and progression. Cardiovascular disorders are of considerable importance as well. In macula, photoreceptor outer segments that are rich in polyunsaturated fatty acids (FA, particularly, docosahexaenoic acid (DHA, are susceptible to free radicals damage. High blood flow velocity and oxygen partial pressure as well as direct sunlight exposure induce oxidative processes. The source of free radicals in photoreceptor cells and retinal pigment epithelium (RPE is an extensive mitochondrial metabolism, photoreceptor outer segments phagocytosis, lipofuscin phototoxic activity and hemoglobin or protoporphyrin precursors photosensitization. Oxidative stress is considered as an universal component of cell depth in necrosis, apoptosis and toxic damage. Antioxidant protective system consists of enzymes (superoxide dismutase, glutathione peroxidase and catalase and non-enzymatic factors (ascorbic acid, alpha tocopherol, retinol, carotenoids. Specific antioxidant food supplement containing ascorbic acid (500 mg, vitamin E (400 IU and beta carotene (15 mg coupled with zinc (80 mg of zinc oxide and copper (2 mg of copper oxide results in 25 % decrease in late-stage AMD development rate. Amongst the agents that can protect retina from oxidative stress and AMD development, carotenoids are of special importance. Lutein and zeaxanthin containing in retina and lens screen blue light from central area of the retina. They also absorb blue light and inhibit free radicals generation thus preventing polyunsaturated FA light destruction. Association between lutein and zeaxanthin intake and late-stage AMD risk was revealed. Amongst the most important factors which deficiency favors macular degeneration are omega-3 FAs, i.e., DHA. DHA is the key component of visual pigment rhodopsin transformation. It

  13. Age-related macular degeneration: prevention and treatment. A review

    Directory of Open Access Journals (Sweden)

    K. A. Mirzabekova

    2014-01-01

    Full Text Available Age-related macular degeneration (AMD is a multifactorial disease. Age, light exposure, smoking, melanin levels and low-antioxidant diet are contributed to AMD development and progression. Cardiovascular disorders are of considerable importance as well. In macula, photoreceptor outer segments that are rich in polyunsaturated fatty acids (FA, particularly, docosahexaenoic acid (DHA, are susceptible to free radicals damage. High blood flow velocity and oxygen partial pressure as well as direct sunlight exposure induce oxidative processes. The source of free radicals in photoreceptor cells and retinal pigment epithelium (RPE is an extensive mitochondrial metabolism, photoreceptor outer segments phagocytosis, lipofuscin phototoxic activity and hemoglobin or protoporphyrin precursors photosensitization. Oxidative stress is considered as an universal component of cell depth in necrosis, apoptosis and toxic damage. Antioxidant protective system consists of enzymes (superoxide dismutase, glutathione peroxidase and catalase and non-enzymatic factors (ascorbic acid, alpha tocopherol, retinol, carotenoids. Specific antioxidant food supplement containing ascorbic acid (500 mg, vitamin E (400 IU and beta carotene (15 mg coupled with zinc (80 mg of zinc oxide and copper (2 mg of copper oxide results in 25 % decrease in late-stage AMD development rate. Amongst the agents that can protect retina from oxidative stress and AMD development, carotenoids are of special importance. Lutein and zeaxanthin containing in retina and lens screen blue light from central area of the retina. They also absorb blue light and inhibit free radicals generation thus preventing polyunsaturated FA light destruction. Association between lutein and zeaxanthin intake and late-stage AMD risk was revealed. Amongst the most important factors which deficiency favors macular degeneration are omega-3 FAs, i.e., DHA. DHA is the key component of visual pigment rhodopsin transformation. It

  14. Genetics of frontotemporal lobar degeneration

    Directory of Open Access Journals (Sweden)

    Aswathy P

    2010-10-01

    Full Text Available Frontotemporal lobar degeneration (FTLD is a highly heterogenous group of progressive neurodegenerative disorders characterized by atrophy of prefrontal and anterior temporal cortices. Recently, the research in the field of FTLD has gained increased attention due to the clinical, neuropathological, and genetic heterogeneity and has increased our understanding of the disease pathogenesis. FTLD is a genetically complex disorder. It has a strong genetic basis and 50% of patients show a positive family history for FTLD. Linkage studies have revealed seven chromosomal loci and a number of genes including MAPT, PGRN, VCP, and CHMB-2B are associated with the disease. Neuropathologically, FTLD is classified into tauopathies and ubiquitinopathies. The vast majority of FTLD cases are characterized by pathological accumulation of tau or TDP-43 positive inclusions, each as an outcome of mutations in MAPT or PGRN, respectively. Identification of novel proteins involved in the pathophysiology of the disease, such as progranulin and TDP-43, may prove to be excellent biomarkers of disease progression and thereby lead to the development of better therapeutic options through pharmacogenomics. However, much more dissections into the causative pathways are needed to get a full picture of the etiology. Over the past decade, advances in research on the genetics of FTLD have revealed many pathogenic mutations leading to different clinical manifestations of the disease. This review discusses the current concepts and recent advances in our understanding of the genetics of FTLD.

  15. Degeneration of biogenic superparamagnetic magnetite.

    Science.gov (United States)

    Li, Y-L; Pfiffner, S M; Dyar, M D; Vali, H; Konhauser, K; Cole, D R; Rondinone, A J; Phelps, T J

    2009-01-01

    Magnetite crystals precipitated as a consequence of Fe(III) reduction by Shewanella algae BrY after 265 h incubation and 5-year anaerobic storage were investigated with transmission electron microscopy, Mössbauer spectroscopy and X-ray diffraction. The magnetite crystals were typically superparamagnetic with an approximate size of 13 nm. The lattice constants of the 265 h and 5-year crystals are 8.4164A and 8.3774A, respectively. The Mössbauer spectra indicated that the 265 h magnetite had excess Fe(II) in its crystal-chemistry (Fe(3+) (1.990)Fe(2+) (1.015)O(4)) but the 5-year magnetite was Fe(II)-deficient in stoichiometry (Fe(3+) (2.388)Fe(2+) (0.419)O(4)). Such crystal-chemical changes may be indicative of the degeneration of superparamagnetic magnetite through the aqueous oxidization of Fe(II) anaerobically, and the concomitant oxidation of the organic phases (fatty acid methyl esters) that were present during the initial formation of the magnetite. The observation of a corona structure on the aged magnetite corroborates the anaerobic oxidation of Fe(II) on the outer layers of magnetite crystals. These results suggest that there may be a possible link between the enzymatic activity of the bacteria and the stability of Fe(II)-excess magnetite, which may help explain why stable nano-magnetite grains are seldom preserved in natural environments.

  16. Degeneration of Biogenic Superparamagnetic Magnetite

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dr. Yi-Liang [University of Tennessee, Knoxville (UTK); Pfiffner, Susan M. [University of Tennessee, Knoxville (UTK); Dyar, Dr. M Darby [Mount Holyoke College; Vali, Dr. Hojatolah [McGill University, Montreal, Quebec; Konhauser, Dr, Kurt [University of Alberta; Cole, David R [ORNL; Rondinone, Adam Justin [ORNL; Phelps, Tommy Joe [ORNL

    2009-01-01

    ABSTRACT. Magnetite crystals precipitated as a consequence of Fe(III) reduction by Shewanella algae BrY after 265 hours incubation and 5-year storage were investigated with transmission electron microscopy, M ssbauer spectroscopy and X-ray diffraction. The magnetite crystals were typically superparamagnetic with an approximate size of 13 nm. The lattice constants of the 265 hour and 5-year crystals are 8.4164 and 8.3774 , respectively. The M ssbauer spectra indicated that the 265 hour magnetite had excess Fe(II) in its crystal-chemistry (Fe3+1.9901Fe2+ 1.0149O4) but the 5-year magnetite was Fe(II)-deficient in stoichiometry (Fe3+2.3875Fe2+0.4188O4). Such crystal-hemical changes may be indicative of the degeneration of superparamagnetic magnetite through the aqueous oxidization of Fe(II) anaerobically, and the concomitant oxidation of the organic phases(fatty acid methyl esters) that were present during the initial formation of the magnetite. The observation of a corona structure on the aged magnetite corroborates the oxidation of Fe(II) on the outer layers of magnetite crystals. These results suggest that there may be a possible link between the enzymatic activity of the bacteria and the stability of Fe(II)-excess magnetite, which may help explain why stable nano-magnetite grains are seldom preserved in natural environments.

  17. Interactive segmentation for geographic atrophy in retinal fundus images

    OpenAIRE

    Lee, Noah; Smith, R. Theodore; Laine, Andrew F.

    2008-01-01

    Fundus auto-fluorescence (FAF) imaging is a non-invasive technique for in vivo ophthalmoscopic inspection of age-related macular degeneration (AMD), the most common cause of blindness in developed countries. Geographic atrophy (GA) is an advanced form of AMD and accounts for 12–21% of severe visual loss in this disorder [3]. Automatic quantification of GA is important for determining disease progression and facilitating clinical diagnosis of AMD. The problem of automatic segmentation of patho...

  18. Open-source software platform for medical image segmentation applications

    Science.gov (United States)

    Namías, R.; D'Amato, J. P.; del Fresno, M.

    2017-11-01

    Segmenting 2D and 3D images is a crucial and challenging problem in medical image analysis. Although several image segmentation algorithms have been proposed for different applications, no universal method currently exists. Moreover, their use is usually limited when detection of complex and multiple adjacent objects of interest is needed. In addition, the continually increasing volumes of medical imaging scans require more efficient segmentation software design and highly usable applications. In this context, we present an extension of our previous segmentation framework which allows the combination of existing explicit deformable models in an efficient and transparent way, handling simultaneously different segmentation strategies and interacting with a graphic user interface (GUI). We present the object-oriented design and the general architecture which consist of two layers: the GUI at the top layer, and the processing core filters at the bottom layer. We apply the framework for segmenting different real-case medical image scenarios on public available datasets including bladder and prostate segmentation from 2D MRI, and heart segmentation in 3D CT. Our experiments on these concrete problems show that this framework facilitates complex and multi-object segmentation goals while providing a fast prototyping open-source segmentation tool.

  19. 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.)

  20. 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.).

  1. Genetics Home Reference: Stargardt macular degeneration

    Science.gov (United States)

    ... recognizing faces. In most people with Stargardt macular degeneration , a fatty yellow pigment (lipofuscin) builds up in cells underlying the macula. Over time, the abnormal accumulation of this substance ...

  2. Ataxias and Cerebellar or Spinocerebellar Degeneration

    Science.gov (United States)

    ... and conducts a broad range of basic and clinical research on cerebellar and spinocerebellar degeneration, including work aimed at finding the cause(s) of ataxias and ways to ... Publications Definition Ataxia ...

  3. Sucrose-Metabolizing Enzymes in Transport Tissues and Adjacent Sink Structures in Developing Citrus Fruit 1

    Science.gov (United States)

    Lowell, Cadance A.; Tomlinson, Patricia T.; Koch, Karen E.

    1989-01-01

    Juice tissues of citrus lack phloem; therefore, photosynthates enroute to juice sacs exit the vascular system on the surface of each segment. Areas of extensive phloem unloading and transport (vascular bundles + segment epidermis) can thus be separated from those of assimilate storage (juice sacs) and adjacent tissues where both processes occur (peel). Sugar composition, dry weight accumulation, and activities of four sucrose-metabolizing enzymes (soluble and cell-wall-bound acid invertase, alkaline invertase, sucrose synthase, and sucrose phosphate synthase) were measured in these transport and sink tissues of grapefruit (Citrus paradisi Macf.) to determine more clearly whether a given enzyme appeared to be more directly associated with assimilate transport versus deposition or utilization. Results were compared at three developmental stages. Activity of sucrose (per gram fresh weight and per milligram protein) extracted from zones of extensive phloem unloading and transport was significantly greater than from adjacent sink tissues during the stages (II and III) when juice sacs grow most rapidly. In stage II fruit, activity of sucrose synthase also significantly surpassed that of all other sucrose-metabolizing enzymes in extracts from the transport tissues (vascular bundles + segment epidermis). In contrast, sucrose phosphate synthase and alkaline invertase at this stage of growth were the most active enzymes from adjacent, rapidly growing, phloem-free sink tissues (juice sacs). Activity of these two enzymes in extracts from juice sacs was significantly greater than that form the transport tissues (vascular bundles + segment epidermis). Soluble acid invertase was the most active enzyme in extracts from all tissues of very young fruit (stage I), including nonvascular regions, but nearly disappeared prior to the onset of juice sac sugar accumulation. The physiological function of high sucrose synthase activity in the transport tissues during rapid sucrose import

  4. Hamiltonization of theories with degenerate coordinates

    International Nuclear Information System (INIS)

    Gitman, D.M.; Tyutin, I.V.

    2002-01-01

    We consider a class of Lagrangian theories where part of the coordinates does not have any time derivatives in the Lagrange function (we call such coordinates degenerate). We advocate that it is reasonable to reconsider the conventional definition of singularity based on the usual Hessian and, moreover, to simplify the conventional hamiltonization procedure. In particular, in such a procedure, it is not necessary to complete the degenerate coordinates with the corresponding conjugate momenta

  5. Hamiltonization of theories with degenerate coordinates

    Energy Technology Data Exchange (ETDEWEB)

    Gitman, D.M. E-mail: gitman@fma.if.usp.br; Tyutin, I.V. E-mail: tyutin@lpi.ru

    2002-05-27

    We consider a class of Lagrangian theories where part of the coordinates does not have any time derivatives in the Lagrange function (we call such coordinates degenerate). We advocate that it is reasonable to reconsider the conventional definition of singularity based on the usual Hessian and, moreover, to simplify the conventional hamiltonization procedure. In particular, in such a procedure, it is not necessary to complete the degenerate coordinates with the corresponding conjugate momenta.

  6. Splitting deformations of degenerations of complex curves towards the classification of atoms of degenerations

    CERN Document Server

    2006-01-01

    The author develops a deformation theory for degenerations of complex curves; specifically, he treats deformations which induce splittings of the singular fiber of a degeneration. He constructs a deformation of the degeneration in such a way that a subdivisor is "barked" (peeled) off from the singular fiber. These "barking deformations" are related to deformations of surface singularities (in particular, cyclic quotient singularities) as well as the mapping class groups of Riemann surfaces (complex curves) via monodromies. Important applications, such as the classification of atomic degenerations, are also explained.

  7. Automated degenerate PCR primer design for high-throughput sequencing improves efficiency of viral sequencing

    Directory of Open Access Journals (Sweden)

    Li Kelvin

    2012-11-01

    Full Text Available Abstract Background In a high-throughput environment, to PCR amplify and sequence a large set of viral isolates from populations that are potentially heterogeneous and continuously evolving, the use of degenerate PCR primers is an important strategy. Degenerate primers allow for the PCR amplification of a wider range of viral isolates with only one set of pre-mixed primers, thus increasing amplification success rates and minimizing the necessity for genome finishing activities. To successfully select a large set of degenerate PCR primers necessary to tile across an entire viral genome and maximize their success, this process is best performed computationally. Results We have developed a fully automated degenerate PCR primer design system that plays a key role in the J. Craig Venter Institute’s (JCVI high-throughput viral sequencing pipeline. A consensus viral genome, or a set of consensus segment sequences in the case of a segmented virus, is specified using IUPAC ambiguity codes in the consensus template sequence to represent the allelic diversity of the target population. PCR primer pairs are then selected computationally to produce a minimal amplicon set capable of tiling across the full length of the specified target region. As part of the tiling process, primer pairs are computationally screened to meet the criteria for successful PCR with one of two described amplification protocols. The actual sequencing success rates for designed primers for measles virus, mumps virus, human parainfluenza virus 1 and 3, human respiratory syncytial virus A and B and human metapneumovirus are described, where >90% of designed primer pairs were able to consistently successfully amplify >75% of the isolates. Conclusions Augmenting our previously developed and published JCVI Primer Design Pipeline, we achieved similarly high sequencing success rates with only minor software modifications. The recommended methodology for the construction of the consensus

  8. Age-related macular degeneration.

    Science.gov (United States)

    Cheung, Lily K; Eaton, Angie

    2013-08-01

    Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly, and the prevalence of the disease increases exponentially with every decade after age 50 years. It is a multifactorial disease involving a complex interplay of genetic, environmental, metabolic, and functional factors. Besides smoking, hypertension, obesity, and certain dietary habits, a growing body of evidence indicates that inflammation and the immune system may play a key role in the development of the disease. AMD may progress from the early form to the intermediate form and then to the advanced form, where two subtypes exist: the nonneovascular (dry) type and the neovascular (wet) type. The results from the Age-Related Eye Disease Study have shown that for the nonneovascular type of AMD, supplementation with high-dose antioxidants (vitamin C, vitamin E, and β-carotene) and zinc is recommended for those with the intermediate form of AMD in one or both eyes or with advanced AMD or vision loss due to AMD in one eye. As for the neovascular type of the advanced AMD, the current standard of therapy is intravitreal injections of vascular endothelial growth factor inhibitors. In addition, lifestyle and dietary modifications including improved physical activity, reduced daily sodium intake, and reduced intake of solid fats, added sugars, cholesterol, and refined grain foods are recommended. To date, no study has demonstrated that AMD can be cured or effectively prevented. Clearly, more research is needed to fully understand the pathophysiology as well as to develop prevention and treatment strategies for this devastating disease. © 2013 Pharmacotherapy Publications, Inc.

  9. Indian hedgehog contributes to human cartilage endplate degeneration.

    Science.gov (United States)

    Wang, Shaowei; Yang, Kun; Chen, Shuai; Wang, Jiying; Du, Guoqing; Fan, Shunwu; Wei, Lei

    2015-08-01

    To determine the role of Indian hedgehog (Ihh) signaling in human cartilage endplate (CEP) degeneration. CEP-degenerated tissues from patients with Modic I or II changes (n = 9 and 45, respectively) and normal tissues from vertebral burst fracture patients (n = 17) were collected. Specimens were either cut into slices for organ culture ex vivo or digested to isolate chondrocytes for cell culture in vitro. Ihh expression and the effect of Ihh on cartilage degeneration were determined by investigating degeneration markers in this study. Ihh expression and cartilage degeneration markers significantly increased in the Modic I and II groups. The expression of cartilage degeneration markers was positively correlated with degeneration severity. Gain-of-function for Ihh promoted expression of cartilage degeneration markers in vitro, while loss-of-function for Ihh inhibited their expression both in vitro and ex vivo. These findings demonstrated that Ihh promotes CEP degeneration. Blocking Ihh pathway has potential clinical usage for attenuating CEP degeneration.

  10. Early Events in Retinal Degeneration Caused by Rhodopsin Mutation or Pigment Epithelium Malfunction: Differences and Similarities

    Science.gov (United States)

    Di Pierdomenico, Johnny; García-Ayuso, Diego; Pinilla, Isabel; Cuenca, Nicolás; Vidal-Sanz, Manuel; Agudo-Barriuso, Marta; Villegas-Pérez, María P.

    2017-01-01

    To study the course of photoreceptor cell death and macro and microglial reactivity in two rat models of retinal degeneration with different etiologies. Retinas from P23H-1 (rhodopsin mutation) and Royal College of Surgeon (RCS, pigment epithelium malfunction) rats and age-matched control animals (Sprague-Dawley and Pievald Viro Glaxo, respectively) were cross-sectioned at different postnatal ages (from P10 to P60) and rhodopsin, L/M- and S-opsin, ionized calcium-binding adapter molecule 1 (Iba1), glial fibrillary acid protein (GFAP), and proliferating cell nuclear antigen (PCNA) proteins were immunodetected. Photoreceptor nuclei rows and microglial cells in the different retinal layers were quantified. Photoreceptor degeneration starts earlier and progresses quicker in P23H-1 than in RCS rats. In both models, microglial cell activation occurs simultaneously with the initiation of photoreceptor death while GFAP over-expression starts later. As degeneration progresses, the numbers of microglial cells increase in the retina, but decreasing in the inner retina and increasing in the outer retina, more markedly in RCS rats. Interestingly, and in contrast with healthy animals, microglial cells reach the outer nuclei and outer segment layers. The higher number of microglial cells in dystrophic retinas cannot be fully accounted by intraretinal migration and PCNA immunodetection revealed microglial proliferation in both models but more importantly in RCS rats. The etiology of retinal degeneration determines the initiation and pattern of photoreceptor cell death and simultaneously there is microglial activation and migration, while the macroglial response is delayed. The actions of microglial cells in the degeneration cannot be explained only in the basis of photoreceptor death because they participate more actively in the RCS model. Thus, the retinal degeneration caused by pigment epithelium malfunction is more inflammatory and would probably respond better to interventions

  11. Biomechanics of Artificial Disc Replacements Adjacent to a 2-Level Fusion in 4-Level Hybrid Constructs: An In Vitro Investigation

    Science.gov (United States)

    Liao, Zhenhua; Fogel, Guy R.; Wei, Na; Gu, Hongsheng; Liu, Weiqiang

    2015-01-01

    Background The ideal procedure for multilevel cervical degenerative disc diseases remains controversial. Recent studies on hybrid surgery combining anterior cervical discectomy and fusion (ACDF) and artificial cervical disc replacement (ACDR) for 2-level and 3-level constructs have been reported in the literature. The purpose of this study was to estimate the biomechanics of 3 kinds of 4-level hybrid constructs, which are more likely to be used clinically compared to 4-level arthrodesis. Material/Methods Eighteen human cadaveric spines (C2–T1) were evaluated in different testing conditions: intact, with 3 kinds of 4-level hybrid constructs (hybrid C3–4 ACDR+C4–6 ACDF+C6–7ACDR; hybrid C3–5ACDF+C5–6ACDR+C6–7ACDR; hybrid C3–4ACDR+C4–5ACDR+C5–7ACDF); and 4-level fusion. Results Four-level fusion resulted in significant decrease in the C3–C7 ROM compared with the intact spine. The 3 different 4-level hybrid treatment groups caused only slight change at the instrumented levels compared to intact except for flexion. At the adjacent levels, 4-level fusion resulted in significant increase of contribution of both upper and lower adjacent levels. However, for the 3 hybrid constructs, significant changes of motion increase far lower than 4P at adjacent levels were only noted in partial loading conditions. No destabilizing effect or hypermobility were observed in any 4-level hybrid construct. Conclusions Four-level fusion significantly eliminated motion within the construct and increased motion at the adjacent segments. For all 3 different 4-level hybrid constructs, ACDR normalized motion of the index segment and adjacent segments with no significant hypermobility. Compared with the 4-level ACDF condition, the artificial discs in 4-level hybrid constructs had biomechanical advantages compared to fusion in normalizing adjacent level motion. PMID:26694835

  12. Semi-automatic geographic atrophy segmentation for SD-OCT images

    OpenAIRE

    Chen, Qiang; de Sisternes, Luis; Leng, Theodore; Zheng, Luoluo; Kutzscher, Lauren; Rubin, Daniel L.

    2013-01-01

    Geographic atrophy (GA) is a condition that is associated with retinal thinning and loss of the retinal pigment epithelium (RPE) layer. It appears in advanced stages of non-exudative age-related macular degeneration (AMD) and can lead to vision loss. We present a semi-automated GA segmentation algorithm for spectral-domain optical coherence tomography (SD-OCT) images. The method first identifies and segments a surface between the RPE and the choroid to generate retinal projection images in wh...

  13. 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.

  14. 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.

  15. Segmentation, advertising and prices

    NARCIS (Netherlands)

    Galeotti, Andrea; Moraga González, José

    This paper explores the implications of market segmentation on firm competitiveness. In contrast to earlier work, here market segmentation is minimal in the sense that it is based on consumer attributes that are completely unrelated to tastes. We show that when the market is comprised by two

  16. Sipunculans and segmentation

    DEFF Research Database (Denmark)

    Wanninger, Andreas; Kristof, Alen; Brinkmann, Nora

    2009-01-01

    mechanisms may act on the level of gene expression, cell proliferation, tissue differentiation and organ system formation in individual segments. Accordingly, in some polychaete annelids the first three pairs of segmental peripheral neurons arise synchronously, while the metameric commissures of the ventral...

  17. Families and degenerations of conformal field theories

    Energy Technology Data Exchange (ETDEWEB)

    Roggenkamp, D.

    2004-09-01

    In this work, moduli spaces of conformal field theories are investigated. In the first part, moduli spaces corresponding to current-current deformation of conformal field theories are constructed explicitly. For WZW models, they are described in detail, and sigma model realizations of the deformed WZW models are presented. The second part is devoted to the study of boundaries of moduli spaces of conformal field theories. For this purpose a notion of convergence of families of conformal field theories is introduced, which admits certain degenerated conformal field theories to occur as limits. To such a degeneration of conformal field theories, a degeneration of metric spaces together with additional geometric structures can be associated, which give rise to a geometric interpretation. Boundaries of moduli spaces of toroidal conformal field theories, orbifolds thereof and WZW models are analyzed. Furthermore, also the limit of the discrete family of Virasoro minimal models is investigated. (orig.)

  18. Intramuscular degeneration process in Duchenne muscular dystrophy

    International Nuclear Information System (INIS)

    Hasegawa, Takeshi; Matsumra, Kiichiro; Hashimoto, Takahiro; Ikehira, Hiroo; Fukuda, Hiroshi; Tateno, Yukio.

    1992-01-01

    Intramuscular degeneration process of Duchenne dystrophy skeletal muscles was investigated by longitudinal skeletal muscle imaging with high-field-strength NMR-CT of 1.5 Tesla. Thigh muscles in 10 cases ranging in age from 4 to 19 years were examined by T 1 -weighted longitudinal images (TR=215∼505 ms, TE=19∼20 ms). The following results were obtained. Skeletal muscle degeneration was depicted as high signal intensity area reflecting its high fat contents. These high signal intensity areas had a longitudinally streaky appearance in parallel direction with myofibers. These findings were more prominent toward myotendon junction than muscle bellies. Skeletal muscle degeneration progressed rapidly between 7 to 10 years of age, and reached a plateau after that. (author)

  19. [Peripheral retinal degenerations--treatment recommendations].

    Science.gov (United States)

    Joussen, A M; Kirchhof, B

    2004-10-01

    This report reviews the clinical appearance of degenerative diseases of the peripheral retina in relationship to the risk of developing a rhegmatogenous retinal detachment. We present recommendations for preventive treatment in eyes at increased risk of developing retinal detachment. Retinal degenerations are common lesions involving the peripheral retina but most of them are clinically insignificant. Lattice degeneration, degenerative retinoschisis, cystic retinal tufts, and very rarely zonular traction tufts can result in rhegmatogenous retinal detachment. Therefore, these lesions have been considered for prophylactic treatment; however, adequate studies have not been performed to date. Most of the peripheral retinal degenerations may not require treatment except in rare, high-risk situations. According to current knowledge there is no higher incidence of secondary pucker or other side effects after laser coagulation. Therefore, generous laser indication is recommended if risk factors apply.

  20. Retinal Cell Degeneration in Animal Models

    Directory of Open Access Journals (Sweden)

    Masayuki Niwa

    2016-01-01

    Full Text Available The aim of this review is to provide an overview of various retinal cell degeneration models in animal induced by chemicals (N-methyl-d-aspartate- and CoCl2-induced, autoimmune (experimental autoimmune encephalomyelitis, mechanical stress (optic nerve crush-induced, light-induced and ischemia (transient retinal ischemia-induced. The target regions, pathology and proposed mechanism of each model are described in a comparative fashion. Animal models of retinal cell degeneration provide insight into the underlying mechanisms of the disease, and will facilitate the development of novel effective therapeutic drugs to treat retinal cell damage.

  1. Kinematic control of robot with degenerate wrist

    Science.gov (United States)

    Barker, L. K.; Moore, M. C.

    1984-01-01

    Kinematic resolved rate equations allow an operator with visual feedback to dynamically control a robot hand. When the robot wrist is degenerate, the computed joint angle rates exceed operational limits, and unwanted hand movements can result. The generalized matrix inverse solution can also produce unwanted responses. A method is introduced to control the robot hand in the region of the degenerate robot wrist. The method uses a coordinated movement of the first and third joints of the robot wrist to locate the second wrist joint axis for movement of the robot hand in the commanded direction. The method does not entail infinite joint angle rates.

  2. Late complications following cryotherapy of lattice degeneration.

    Science.gov (United States)

    Benson, W E; Morse, P H; Nantawan, P

    1977-10-01

    We observed 341 patients who had received cryotherapy for lattice degeneration in order to identify possible late complications. Sequelae such as retinal tears posterior to an operculum or flap tears within treated areas showed that treatment did not necessarily prevent subsequent vitreous traction. Moreover, the newly created flap tears may extend beyond the treated area and can cause retinal detachment. Even scleral buckling did not necesserily prevent further traction. Therefore, we concluded that when cryotherapy is used to treat lattice degeneration, an adequate margin of surrounding retina should be treated and the treatment should extend to the ora serrata.

  3. Genetics of lattice degeneration of the retina.

    Science.gov (United States)

    Murakami, F; Ohba, N

    1982-01-01

    First-degree relatives of proband patients with lattice degeneration of the retina revealed a significantly higher prevalence of the disease than the prevalence in the general population: the former had the disease about three times as frequently as the latter. The observed data were analyzed in terms of their accordance with recognized genetic models. The inheritance pattern did not fit well to a monogenic mode of inheritance, and it was hypothesized that a polygenic or multifactorial mode of inheritance is the most likely for lattice degeneration of the retina.

  4. CT of sarcomatous degeneration in neurofibromatosis

    International Nuclear Information System (INIS)

    Coleman, B.G.; Arger, P.H.; Dalinka, M.K.; Obringer, A.C.; Raney, B.R.; Meadows, A.T.

    1983-01-01

    Neurofibromatosis is a relatively common disorder that often involves many organ systems. One of the least understood aspects of this malady is a well documented potential for sarcomatous degeneration of neurofibromas. The inability to identify patients at risk and the lack of noninvasive screening methods for symptomatic patients often leads to late diagnosis. In six of seven subsequently proven neurofibrosarcomas, CT demonstrated low-density areas that histopathologically appeared to be due to necrosis, hemorrhage, and/or cystic degeneration. The density differences within these sarcomas were enhanced by the intravenous adminstration of iodinated contrast agents

  5. Role of calpains in the injury-induced dysfunction and degeneration of the mammalian axon.

    Science.gov (United States)

    Ma, Marek

    2013-12-01

    Axonal injury and degeneration, whether primary or secondary, contribute to the morbidity and mortality seen in many acquired and inherited central nervous system (CNS) and peripheral nervous system (PNS) disorders, such as traumatic brain injury, spinal cord injury, cerebral ischemia, neurodegenerative diseases, and peripheral neuropathies. The calpain family of proteases has been mechanistically linked to the dysfunction and degeneration of axons. While the direct mechanisms by which transection, mechanical strain, ischemia, or complement activation trigger intra-axonal calpain activity are likely different, the downstream effects of unregulated calpain activity may be similar in seemingly disparate diseases. In this review, a brief examination of axonal structure is followed by a focused overview of the calpain family. Finally, the mechanisms by which calpains may disrupt the axonal cytoskeleton, transport, and specialized domains (axon initial segment, nodes, and terminals) are discussed. © 2013.

  6. Pancreas and cyst segmentation

    Science.gov (United States)

    Dmitriev, Konstantin; Gutenko, Ievgeniia; Nadeem, Saad; Kaufman, Arie

    2016-03-01

    Accurate segmentation of abdominal organs from medical images is an essential part of surgical planning and computer-aided disease diagnosis. Many existing algorithms are specialized for the segmentation of healthy organs. Cystic pancreas segmentation is especially challenging due to its low contrast boundaries, variability in shape, location and the stage of the pancreatic cancer. We present a semi-automatic segmentation algorithm for pancreata with cysts. In contrast to existing automatic segmentation approaches for healthy pancreas segmentation which are amenable to atlas/statistical shape approaches, a pancreas with cysts can have even higher variability with respect to the shape of the pancreas due to the size and shape of the cyst(s). Hence, fine results are better attained with semi-automatic steerable approaches. We use a novel combination of random walker and region growing approaches to delineate the boundaries of the pancreas and cysts with respective best Dice coefficients of 85.1% and 86.7%, and respective best volumetric overlap errors of 26.0% and 23.5%. Results show that the proposed algorithm for pancreas and pancreatic cyst segmentation is accurate and stable.

  7. Segmentation of consumer's markets and evaluation of market's segments

    OpenAIRE

    ŠVECOVÁ, Iveta

    2013-01-01

    The goal of this bachelor thesis was to explain a possibly segmentation of consumer´s markets for a chosen company, and to present a suitable goods offer, so it would be suitable to the needs of selected segments. The work is divided into theoretical and practical part. First part describes marketing, segmentation, segmentation of consumer's markets, consumer's market, market's segments a other terms. Second part describes an evaluation of questionnaire survey, discovering of market's segment...

  8. Production of linear polarization by segmentation of helical undulator

    International Nuclear Information System (INIS)

    Tanaka, T.; Kitamura, H.

    2002-01-01

    A simple scheme to obtain linearly polarized radiation (LPR) with a segmented undulator is proposed. The undulator is composed of several segments each of which forms a helical undulator and has helicity opposite to those of adjacent segments. Due to coherent sum of radiation, the circularly polarized component is canceled out resulting in production of LPR without any higher harmonics. The radiation from the proposed device is investigated analytically, which shows that a high degree of linear polarization is obtained in spite of a finite beam emittance and angular acceptance of optics, if a sufficiently large number of segments and an adequate photon energy are chosen. Results of calculation to investigate practical performances of the proposed device are presented

  9. Optical Coherence Tomography of Retinal Degeneration in Royal College of Surgeons Rats and Its Correlation with Morphology and Electroretinography

    Science.gov (United States)

    Yamauchi, Kodai; Mounai, Natsuki; Tanabu, Reiko; Nakazawa, Mitsuru

    2016-01-01

    Purpose To evaluate the correlation between optical coherence tomography (OCT) and the histological, ultrastructural and electroretinography (ERG) findings of retinal degeneration in Royal College of Surgeons (RCS-/-) rats. Materials and Methods Using OCT, we qualitatively and quantitatively observed the continual retinal degeneration in RCS-/- rats, from postnatal (PN) day 17 until PN day 111. These findings were compared with the corresponding histological, electron microscopic, and ERG findings. We also compared them to OCT findings in wild type RCS+/+ rats, which were used as controls. Results After PN day 17, the hyperreflective band at the apical side of the photoreceptor layer became blurred. The inner segment (IS) ellipsoid zone then became obscured, and the photoreceptor IS and outer segment (OS) layers became diffusely hyperreflective after PN day 21. These changes correlated with histological and electron microscopic findings showing extracellular lamellar material that accumulated in the photoreceptor OS layer. After PN day 26, the outer nuclear layer became significantly thinner (P RCS-/- and RCS+/+ rats. Conclusion Our results suggest that OCT demonstrates histologically validated photoreceptor degeneration in RCS rats, and that OCT findings partly correlate with ERG findings. We propose that OCT is a less invasive and useful method for evaluating photoreceptor degeneration in animal models of retinitis pigmentosa. PMID:27644042

  10. Driving and Age-Related Macular Degeneration

    OpenAIRE

    Owsley, Cynthia; McGwin, Gerald

    2008-01-01

    This article reviews the research literature on driving and age-related macular degeneration, which is motivated by the link between driving and the quality of life of older adults and their increased collision rate. It addresses the risk of crashes, driving performance, driving difficulty, self-regulation, and interventions to enhance, safety, and considers directions for future research.

  11. Specific heats of degenerate ideal gases

    OpenAIRE

    Caruso, Francisco; Oguri, Vitor; Silveira, Felipe

    2017-01-01

    From arguments based on Heisenberg's uncertainty principle and Pauli's exclusion principle, the molar specific heats of degenerate ideal gases at low temperatures are estimated, giving rise to values consistent with the Nerst-Planck Principle (third law of Thermodynamics). The Bose-Einstein condensation phenomenon based on the behavior of specific heat of massive and non-relativistic boson gases is also presented.

  12. Ecological transition predictably associated with gene degeneration.

    Science.gov (United States)

    Wessinger, Carolyn A; Rausher, Mark D

    2015-02-01

    Gene degeneration or loss can significantly contribute to phenotypic diversification, but may generate genetic constraints on future evolutionary trajectories, potentially restricting phenotypic reversal. Such constraints may manifest as directional evolutionary trends when parallel phenotypic shifts consistently involve gene degeneration or loss. Here, we demonstrate that widespread parallel evolution in Penstemon from blue to red flowers predictably involves the functional inactivation and degeneration of the enzyme flavonoid 3',5'-hydroxylase (F3'5'H), an anthocyanin pathway enzyme required for the production of blue floral pigments. Other types of genetic mutations do not consistently accompany this phenotypic shift. This pattern may be driven by the relatively large mutational target size of degenerative mutations to this locus and the apparent lack of associated pleiotropic effects. The consistent degeneration of F3'5'H may provide a mechanistic explanation for the observed asymmetry in the direction of flower color evolution in Penstemon: Blue to red transitions are common, but reverse transitions have not been observed. Although phenotypic shifts in this system are likely driven by natural selection, internal constraints may generate predictable genetic outcomes and may restrict future evolutionary trajectories. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Geometry of non-degenerate Susskind fermions

    International Nuclear Information System (INIS)

    Mitra, P.

    1983-01-01

    The Dirac-Kaehler equation on the lattice is known to describe the degenerate ''flavours'' appering in Susskind's approach to lattice fermions. We study the modification that has to be made in this equation in order to lift the degeneracy and give the flavours arbitrary different masses. (orig.)

  14. Exploring Nonconvex, Crossed and Degenerate Polygons

    Science.gov (United States)

    Contreras, Jose N.

    2004-01-01

    An exploration of nonconvex, crossed, and degenerate polygons (NCCDPs) are described with the help of examples with pedagogical tips and recommendations that are found useful when teaching the mathematical process of extending geometric patterns to NCCDPs. The study concludes that investigating such extensions with interactive geometry software…

  15. Degenerate parabolic stochastic partial differential equations

    Czech Academy of Sciences Publication Activity Database

    span class="emphasis">Hofmanová, Martinaspan>

    2013-01-01

    Roč. 123, č. 12 (2013), s. 4294-4336 ISSN 0304-4149 R&D Projects: GA ČR GAP201/10/0752 Institutional support: RVO:67985556 Keywords : kinetic solutions * degenerate stochastic parabolic equations Subject RIV: BA - General Mathematics Impact factor: 1.046, year: 2013 http://library.utia.cas.cz/separaty/2013/SI/hofmanova-0397241.pdf

  16. MR findings of degenerating parenchymal neurocysticercosis

    International Nuclear Information System (INIS)

    Lee, Yul; Chung, Eun A; Yang, Ik; Park, Hae Jung; Chung, Soo Young

    1996-01-01

    To evaluate MR imaging findings of degenerating parenchymal neurocysticercosis and to determine the characteristics which distinguish it from other brain diseases. MR imagings of 19 patients (56 lesions) of degenerating parenchymal neurocysticercosis were retrospectively evaluated, focusing on the size and location of lesions signal intensity patterns of cyst fluid and wall, the extent of the surrounding edema and features of contrast enhancement. Degenerating parenchymal neurocysticercosis was located in gray or subcortical while matter in 89.3% of 56 lesions (50/56) ; most of these (98.2%) were smaller than 2 cm in diameter. Cyst fluid signal was hyperintense relative to CSF on T1 and proton density weighted images (92.9%). A hypointense signal rim of the cyst wall was noted in the lesions on proton density (92.9%) and T2 weighted (98.2%) images, Surrounding edema was mostly mild. Peripheral rim enhancement was noted in all lesions, and this was frequently irregular and lobulated (67.9%) with a focal defect in the enhancing rim(41.1%). Findings which could be helpful in distinguishing degenerating parencymal neurocysticercosis from other brain diseases are as follows : small, superficial lesions ; hyperintense signal of the cyst fluid on T1 and proton density weighted images ; hypointense signal of the cyst wall on proton density and T2 weighted images ; relatively mild extent of surrounding edema, and peripheral rim enhancement which is frequently irregular and lobulated with a focal defect in the enhancing rim

  17. Degenerate conformal theories on higher-genus surfaces

    International Nuclear Information System (INIS)

    Gerasimov, A.A.

    1989-01-01

    Two-dimensional degenerate field theories on higher-genus surfaces are investigated. Objects are built on the space of moduli, whose linear combinations are hypothetically conformal blocks in degenerate theories

  18. Degeneration of the cervical disc: histology compared with radiography and magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Christe, A.; Vock, P. [University of Berne, Department of Radiology, Inselspital, Berne (Switzerland); Laeubli, R.; Berlemann, U. [University of Berne, Department of Orthopaedic Surgery, Inselspital, Berne (Switzerland); Guzman, R.; Schroth, G. [University of Berne, Department of Neuroradiology, Inselspital, Berne (Switzerland); Moore, R.J. [Institute of Medical and Veterinary Science, Adelaide (Australia); Loevblad, K.O. [University of Berne, Department of Neuroradiology, Inselspital, Berne (Switzerland); Geneva University Hospital, Neuroradiology SRRI, Geneva 14 (Switzerland)

    2005-10-01

    Decisions about the treatment of neck pain are largely made on the basis of information gained from plain X-rays and magnetic resonance imaging (MRI), which are used routinely as part of preliminary investigation. We performed a descriptive cadaveric study to compare histology with radiography and MRI. We correlated plain radiography, disc height [Farfan index (FI)] and MRI findings with histology to assess the ability of radiology to detect significant pathologic lesions. The study included 52 motion segments from nine subjects over the age of 50, who underwent routine hospital autopsy. Disc degeneration was assessed by histology, radiography, disc height (FI: anterior disc height plus posterior disc height divided by anterioposterior diameter) and MRI using established grading systems. Most of the discs were classified radiologically as grade 1 (19/52), grade 2 (13/52), grade 3 (9/52) or grade 4 (3/52). Eight of the discs were graded as normal. The distribution of MRI grades was grade 0 (9/36), grade 1 (9/36), grade 2 (7/36), grade 3 (8/36) and grade 4 (3/36). Half of the discs (26/52) showed advanced (grade 4) degeneration histologically. FI correlated with histological grade (P=0.013), MRI grade (P=0.02) and radiological grade (P<0.001) of degeneration. Radiological and histological grade of degeneration showed a weak correlation (r=0.3, P=0.033). MRI correlated with overall histological grade (r=0.41, P=0.015, n=34). Histological features (e.g., tears, rim lesions, prolapse of nucleus material) were poorly recognised by MRI, which had a sensitivity for disc material prolapse and annulus tears of less than 40%. Our study showed that discs from patients over 50 years are histologically severely degenerated; however, these changes may not be detected by conventional radiography and MRI. (orig.)

  19. Degeneration of the cervical disc: histology compared with radiography and magnetic resonance imaging

    International Nuclear Information System (INIS)

    Christe, A.; Vock, P.; Laeubli, R.; Berlemann, U.; Guzman, R.; Schroth, G.; Moore, R.J.; Loevblad, K.O.

    2005-01-01

    Decisions about the treatment of neck pain are largely made on the basis of information gained from plain X-rays and magnetic resonance imaging (MRI), which are used routinely as part of preliminary investigation. We performed a descriptive cadaveric study to compare histology with radiography and MRI. We correlated plain radiography, disc height [Farfan index (FI)] and MRI findings with histology to assess the ability of radiology to detect significant pathologic lesions. The study included 52 motion segments from nine subjects over the age of 50, who underwent routine hospital autopsy. Disc degeneration was assessed by histology, radiography, disc height (FI: anterior disc height plus posterior disc height divided by anterioposterior diameter) and MRI using established grading systems. Most of the discs were classified radiologically as grade 1 (19/52), grade 2 (13/52), grade 3 (9/52) or grade 4 (3/52). Eight of the discs were graded as normal. The distribution of MRI grades was grade 0 (9/36), grade 1 (9/36), grade 2 (7/36), grade 3 (8/36) and grade 4 (3/36). Half of the discs (26/52) showed advanced (grade 4) degeneration histologically. FI correlated with histological grade (P=0.013), MRI grade (P=0.02) and radiological grade (P<0.001) of degeneration. Radiological and histological grade of degeneration showed a weak correlation (r=0.3, P=0.033). MRI correlated with overall histological grade (r=0.41, P=0.015, n=34). Histological features (e.g., tears, rim lesions, prolapse of nucleus material) were poorly recognised by MRI, which had a sensitivity for disc material prolapse and annulus tears of less than 40%. Our study showed that discs from patients over 50 years are histologically severely degenerated; however, these changes may not be detected by conventional radiography and MRI. (orig.)

  20. MR imaging of central nervous system white matter tract degeneration (Wallerian degeneration)

    International Nuclear Information System (INIS)

    Kuhn, M.J.; Johnson, K.A.; Davis, K.R.

    1987-01-01

    Wallerian degeneration is readily demonstrated by MR imaging. Twenty-one patients with MR signal abnormalities in various central nervous system (CNS) white matter tracts were evaluated with regard to (1) nature of signal abnormality, (2) MR anatomy of the involved tract, and (3) primary pathology (e.g., infarct, tumor, hemorrhage). Most examples of wallerian degeneration result in a thin, continuous band of long T1, long T2 signal abnormality conforming to the known anatomic pathway of a CNS axonal tract. Old, large cortical infarcts have the greatest propensity to show subsequent white-matter tract degeneration. Corticospinal tract degeneration is the type most readily visualized, often seen extending completely from the cerebral cortex through the medulla

  1. Quantitative Characteristics of Spectral-Domain Optical Coherence Tomography in Corresponding Areas of Increased Autofluorescence at the Margin of Geographic Atrophy in Patients With Age-Related Macular Degeneration.

    Science.gov (United States)

    Hariri, Amir H; Nittala, Muneeswar G; Sadda, SriniVas R

    2016-06-01

    To evaluate the spectral-domain optical coherence tomography (SD-OCT) characteristics of the junctional zone corresponding to areas of increased autofluorescence (IAF) at the margin of geographic atrophy (GA) in patients with age-related macular degeneration (AMD). SD-OCT and fundus autofluorescence (FAF) images from untreated eyes with GA available from archived studies at Doheny Image Reading Center were evaluated. Areas of definite decreased autofluorescence (DDAF) corresponding to GA, and areas of IAF at the margins of the GA were manually segmented. Eyes with evidence of IAF were selected. Following manual registration of FAF and OCT data, areas of IAF and normal fluorescence were correlated with OCT features at these locations. Thirty eyes were included. The mean retinal pigment epithelium (RPE) thickness in areas of IAF was 40.6 µm ± 7.69 µm, compared to 28.8 µm ± 7.09 µm in normal adjacent areas (P Retina. 2016;47:523-527.]. Copyright 2016, SLACK Incorporated.

  2. Neuromuscular adaptations induced by adjacent joint training.

    Science.gov (United States)

    Ema, R; Saito, I; Akagi, R

    2018-03-01

    Effects of resistance training are well known to be specific to tasks that are involved during training. However, it remains unclear whether neuromuscular adaptations are induced after adjacent joint training. This study examined the effects of hip flexion training on maximal and explosive knee extension strength and neuromuscular performance of the rectus femoris (RF, hip flexor, and knee extensor) compared with the effects of knee extension training. Thirty-seven untrained young men were randomly assigned to hip flexion training, knee extension training, or a control group. Participants in the training groups completed 4 weeks of isometric hip flexion or knee extension training. Standardized differences in the mean change between the training groups and control group were interpreted as an effect size, and the substantial effect was assumed to be ≥0.20 of the between-participant standard deviation at baseline. Both types of training resulted in substantial increases in maximal (hip flexion training group: 6.2% ± 10.1%, effect size = 0.25; knee extension training group: 20.8% ± 9.9%, effect size = 1.11) and explosive isometric knee extension torques and muscle thickness of the RF in the proximal and distal regions. Improvements in strength were accompanied by substantial enhancements in voluntary activation, which was determined using the twitch interpolation technique and RF activation. Differences in training effects on explosive torques and neural variables between the two training groups were trivial. Our findings indicate that hip flexion training results in substantial neuromuscular adaptations during knee extensions similar to those induced by knee extension training. © 2017 The Authors. Scandinavian Journal of Medicine & Science In Sports Published by John Wiley & Sons Ltd.

  3. Ethanol Exposure Causes Muscle Degeneration in Zebrafish

    Directory of Open Access Journals (Sweden)

    Elizabeth C. Coffey

    2018-03-01

    Full Text Available Alcoholic myopathies are characterized by neuromusculoskeletal symptoms such as compromised movement and weakness. Although these symptoms have been attributed to neurological damage, EtOH may also target skeletal muscle. EtOH exposure during zebrafish primary muscle development or adulthood results in smaller muscle fibers. However, the effects of EtOH exposure on skeletal muscle during the growth period that follows primary muscle development are not well understood. We determined the effects of EtOH exposure on muscle during this phase of development. Strikingly, muscle fibers at this stage are acutely sensitive to EtOH treatment: EtOH induces muscle degeneration. The severity of EtOH-induced muscle damage varies but muscle becomes more refractory to EtOH as muscle develops. NF-kB induction in muscle indicates that EtOH triggers a pro-inflammatory response. EtOH-induced muscle damage is p53-independent. Uptake of Evans blue dye shows that EtOH treatment causes sarcolemmal instability before muscle fiber detachment. Dystrophin-null sapje mutant zebrafish also exhibit sarcolemmal instability. We tested whether Trichostatin A (TSA, which reduces muscle degeneration in sapje mutants, would affect EtOH-treated zebrafish. We found that TSA and EtOH are a lethal combination. EtOH does, however, exacerbate muscle degeneration in sapje mutants. EtOH also disrupts adhesion of muscle fibers to their extracellular matrix at the myotendinous junction: some detached muscle fibers retain beta-Dystroglycan indicating failure of muscle end attachments. Overexpression of Paxillin, which reduces muscle degeneration in zebrafish deficient for beta-Dystroglycan, is not sufficient to rescue degeneration. Taken together, our results suggest that EtOH exposure has pleiotropic deleterious effects on skeletal muscle.

  4. Segmental tuberculosis verrucosa cutis

    Directory of Open Access Journals (Sweden)

    Hanumanthappa H

    1994-01-01

    Full Text Available A case of segmental Tuberculosis Verrucosa Cutis is reported in 10 year old boy. The condition was resembling the ascending lymphangitic type of sporotrichosis. The lesions cleared on treatment with INH 150 mg daily for 6 months.

  5. Chromosome condensation and segmentation

    International Nuclear Information System (INIS)

    Viegas-Pequignot, E.M.

    1981-01-01

    Some aspects of chromosome condensation in mammalians -humans especially- were studied by means of cytogenetic techniques of chromosome banding. Two further approaches were adopted: a study of normal condensation as early as prophase, and an analysis of chromosome segmentation induced by physical (temperature and γ-rays) or chemical agents (base analogues, antibiotics, ...) in order to show out the factors liable to affect condensation. Here 'segmentation' means an abnormal chromosome condensation appearing systematically and being reproducible. The study of normal condensation was made possible by the development of a technique based on cell synchronization by thymidine and giving prophasic and prometaphasic cells. Besides, the possibility of inducing R-banding segmentations on these cells by BrdU (5-bromodeoxyuridine) allowed a much finer analysis of karyotypes. Another technique was developed using 5-ACR (5-azacytidine), it allowed to induce a segmentation similar to the one obtained using BrdU and identify heterochromatic areas rich in G-C bases pairs [fr

  6. International EUREKA: Initialization Segment

    International Nuclear Information System (INIS)

    1982-02-01

    The Initialization Segment creates the starting description of the uranium market. The starting description includes the international boundaries of trade, the geologic provinces, resources, reserves, production, uranium demand forecasts, and existing market transactions. The Initialization Segment is designed to accept information of various degrees of detail, depending on what is known about each region. It must transform this information into a specific data structure required by the Market Segment of the model, filling in gaps in the information through a predetermined sequence of defaults and built in assumptions. A principal function of the Initialization Segment is to create diagnostic messages indicating any inconsistencies in data and explaining which assumptions were used to organize the data base. This permits the user to manipulate the data base until such time the user is satisfied that all the assumptions used are reasonable and that any inconsistencies are resolved in a satisfactory manner

  7. 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

  8. Calcium channel blockers inhibit retinal degeneration in the retinal-degeneration-B mutant of Drosophila.

    Science.gov (United States)

    Sahly, I; Bar Nachum, S; Suss-Toby, E; Rom, A; Peretz, A; Kleiman, J; Byk, T; Selinger, Z; Minke, B

    1992-01-01

    Light accelerates degeneration of photoreceptor cells of the retinal degeneration B (rdgB) mutant of Drosophila. During early stages of degeneration, light stimuli evoke spikes from photoreceptors of the mutant fly; no spikes can be recorded from photoreceptors of the wild-type fly. Production of spike potentials from mutant photoreceptors was blocked by diltiazem, verapamil hydrochloride, and cadmium. Little, if any, effect of the (-)-cis isomer or (+)-cis isomer of diltiazem on the light response was seen. Further, the (+)-cis isomer was approximately 50 times more effective than the (-)-cis isomer in blocking the Ca2+ spikes, indicating that diltiazem action on the rdgB eye is mediated by means of blocking voltage-sensitive Ca2+ channels, rather than by blocking the light-sensitive channels. Application of the Ca(2+)-channel blockers (+)-cis-diltiazem and verapamil hydrochloride to the eyes of rdgB flies over a 7-day period largely inhibited light-dependent degeneration of the photoreceptor cells. Pulse labeling with [32P]phosphate showed much greater incorporation into eye proteins of [32P]phosphate in rdgB flies than in wild-type flies. Retarding the light-induced photoreceptor degeneration in the mutant by Ca(2+)-channel blockers, thus, suggests that toxic increase in intracellular Ca2+ by means of voltage-gated Ca2+ channels, possibly secondary to excessive phosphorylation, leads to photoreceptor degeneration in the rdgB mutant. Images PMID:1309615

  9. Fluence map segmentation

    International Nuclear Information System (INIS)

    Rosenwald, J.-C.

    2008-01-01

    The lecture addressed the following topics: 'Interpreting' the fluence map; The sequencer; Reasons for difference between desired and actual fluence map; Principle of 'Step and Shoot' segmentation; Large number of solutions for given fluence map; Optimizing 'step and shoot' segmentation; The interdigitation constraint; Main algorithms; Conclusions on segmentation algorithms (static mode); Optimizing intensity levels and monitor units; Sliding window sequencing; Synchronization to avoid the tongue-and-groove effect; Accounting for physical characteristics of MLC; Importance of corrections for leaf transmission and offset; Accounting for MLC mechanical constraints; The 'complexity' factor; Incorporating the sequencing into optimization algorithm; Data transfer to the treatment machine; Interface between R and V and accelerator; and Conclusions on fluence map segmentation (Segmentation is part of the overall inverse planning procedure; 'Step and Shoot' and 'Dynamic' options are available for most TPS (depending on accelerator model; The segmentation phase tends to come into the optimization loop; The physical characteristics of the MLC have a large influence on final dose distribution; The IMRT plans (MU and relative dose distribution) must be carefully validated). (P.A.)

  10. Gamifying Video Object Segmentation.

    Science.gov (United States)

    Spampinato, Concetto; Palazzo, Simone; Giordano, Daniela

    2017-10-01

    Video object segmentation can be considered as one of the most challenging computer vision problems. Indeed, so far, no existing solution is able to effectively deal with the peculiarities of real-world videos, especially in cases of articulated motion and object occlusions; limitations that appear more evident when we compare the performance of automated methods with the human one. However, manually segmenting objects in videos is largely impractical as it requires a lot of time and concentration. To address this problem, in this paper we propose an interactive video object segmentation method, which exploits, on one hand, the capability of humans to identify correctly objects in visual scenes, and on the other hand, the collective human brainpower to solve challenging and large-scale tasks. In particular, our method relies on a game with a purpose to collect human inputs on object locations, followed by an accurate segmentation phase achieved by optimizing an energy function encoding spatial and temporal constraints between object regions as well as human-provided location priors. Performance analysis carried out on complex video benchmarks, and exploiting data provided by over 60 users, demonstrated that our method shows a better trade-off between annotation times and segmentation accuracy than interactive video annotation and automated video object segmentation approaches.

  11. Strategic market segmentation

    Directory of Open Access Journals (Sweden)

    Maričić Branko R.

    2015-01-01

    Full Text Available Strategic planning of marketing activities is the basis of business success in modern business environment. Customers are not homogenous in their preferences and expectations. Formulating an adequate marketing strategy, focused on realization of company's strategic objectives, requires segmented approach to the market that appreciates differences in expectations and preferences of customers. One of significant activities in strategic planning of marketing activities is market segmentation. Strategic planning imposes a need to plan marketing activities according to strategically important segments on the long term basis. At the same time, there is a need to revise and adapt marketing activities on the short term basis. There are number of criteria based on which market segmentation is performed. The paper will consider effectiveness and efficiency of different market segmentation criteria based on empirical research of customer expectations and preferences. The analysis will include traditional criteria and criteria based on behavioral model. The research implications will be analyzed from the perspective of selection of the most adequate market segmentation criteria in strategic planning of marketing activities.

  12. Degenerate r-Stirling Numbers and r-Bell Polynomials

    Science.gov (United States)

    Kim, T.; Yao, Y.; Kim, D. S.; Jang, G.-W.

    2018-01-01

    The purpose of this paper is to exploit umbral calculus in order to derive some properties, recurrence relations, and identities related to the degenerate r-Stirling numbers of the second kind and the degenerate r-Bell polynomials. Especially, we will express the degenerate r-Bell polynomials as linear combinations of many well-known families of special polynomials.

  13. Effect of pharmacologically induced retinal degeneration on retinal autofluorescence lifetimes in mice.

    Science.gov (United States)

    Dysli, Chantal; Dysli, Muriel; Zinkernagel, Martin S; Enzmann, Volker

    2016-12-01

    Fluorescence lifetime imaging ophthalmoscopy (FLIO) was used to investigate retinal autofluorescence lifetimes in mouse models of pharmacologically induced retinal degeneration over time. Sodium iodate (NaIO 3 , 35 mg/kg intravenously) was used to induce retinal pigment epithelium (RPE) degeneration with subsequent loss of photoreceptors (PR) whereas N-methyl-N-nitrosourea (MNU, 45 mg/kg intraperitoneally) was employed for degeneration of the photoreceptor cell layer alone. All mice were measured at day 3, 7, 14, and 28 after the respective injection of NaIO 3 , MNU or NaCl (control). Fluorescence lifetime imaging was performed using a fluorescence lifetime imaging ophthalmoscope (Heidelberg Engineering, Heidelberg, Germany). Fluorescence was excited at 473 nm and fluorescence lifetimes were measured in a short and a long spectral channel (498-560 nm and 560-720 nm). Corresponding optical coherence tomography (OCT) images were consecutively acquired and histology was performed at the end of the experiments. Segmentation of OCT images and histology verified the cell type-specific degeneration process over time. Retinal autofluorescence lifetimes increased from day 3 to day 28 in mice after NaIO 3 treatment. Finally, at day 28, fluorescence lifetimes were prolonged by 8% in the short and 61% in the long spectral channel compared to control animals (p = 0.21 and p = 0.004, respectively). In mice after MNU treatment, the mean retinal autofluorescence lifetimes were already decreased at day 3 and retinal lifetimes were finally shortened by 27% in the short and 51% in the long spectral channel at day 28 (p = 0.0028). In conclusion, degeneration of the RPE with subsequent photoreceptor degeneration by NaIO 3 lead to longer mean fluorescence lifetimes of the retina compared to control mice, whereas during specific degeneration of the photoreceptor layer induced by MNU shorter lifetimes were measured. Therefore, short retinal fluorescence lifetimes may originate

  14. Using tracheal segments for replacement of cervical oesophagus: an experimental study.

    Science.gov (United States)

    Abbasidezfouli, Azizollah; Sharifi, Davood; Sasani, Farhang; Ansari, Damoon; Abarkar, Mohammad; Rahmanijoo, Nasrin; Abbasidezfouli, Golbahar; Sheikhy, Kambiz

    2012-03-01

    Segmental resection and anastomosis of oesophageal lesions are not performed as a routine clinical practice because of complications and associated problems, whereas tracheal resection and anastomosis are a routine clinical practice. In this experimental study, we resected a segment of cervical oesophagus and replaced it with a tracheal segment. In eight dogs (mixed races), weighing 20-30 kg, ageing 1-2 years, under general anaesthesia, through a cervical incision, 5 cm of cervical trachea was separated while preserving its attachments to surrounding fibroareolar tissues. Afterwards, 5 cm of the oesophagus was resected and replaced with a prepared segment of the trachea. Oral liquids were started at the first post-operative day; the animals were kept for 2 months and then euthanized. Quality of swallowing and voice were evaluated. After an autopsy, anastomoses were examined grossly and histopathologically. No complications occurred during surgery. Swallowing function and voice were normal in all eight dogs after the operation. No sign of aspiration was seen in clinical and radiographic examinations after starting oral diet. In autopsy examination, anastomoses were patent without narrowing or abnormal mucosal changes. Remarkable histopathological findings in replaced tracheal segments were squamous metaplasia, atrophy and degeneration of mucosal glands and degeneration of cartilages. Replacement of a segment of the oesophagus with an autogenous tracheal segment is a practical procedure with low complications and can probably be used for the treatment of cervical oesophageal lesions in human beings.

  15. Segmented block copolymers with monodisperse aramide end-segments

    NARCIS (Netherlands)

    Araichimani, A.; Gaymans, R.J.

    2008-01-01

    Segmented block copolymers were synthesized using monodisperse diaramide (TT) as hard segments and PTMO with a molecular weight of 2 900 g · mol-1 as soft segments. The aramide: PTMO segment ratio was increased from 1:1 to 2:1 thereby changing the structure from a high molecular weight multi-block

  16. Rediscovering market segmentation.

    Science.gov (United States)

    Yankelovich, Daniel; Meer, David

    2006-02-01

    In 1964, Daniel Yankelovich introduced in the pages of HBR the concept of nondemographic segmentation, by which he meant the classification of consumers according to criteria other than age, residence, income, and such. The predictive power of marketing studies based on demographics was no longer strong enough to serve as a basis for marketing strategy, he argued. Buying patterns had become far better guides to consumers' future purchases. In addition, properly constructed nondemographic segmentations could help companies determine which products to develop, which distribution channels to sell them in, how much to charge for them, and how to advertise them. But more than 40 years later, nondemographic segmentation has become just as unenlightening as demographic segmentation had been. Today, the technique is used almost exclusively to fulfill the needs of advertising, which it serves mainly by populating commercials with characters that viewers can identify with. It is true that psychographic types like "High-Tech Harry" and "Joe Six-Pack" may capture some truth about real people's lifestyles, attitudes, self-image, and aspirations. But they are no better than demographics at predicting purchase behavior. Thus they give corporate decision makers very little idea of how to keep customers or capture new ones. Now, Daniel Yankelovich returns to these pages, with consultant David Meer, to argue the case for a broad view of nondemographic segmentation. They describe the elements of a smart segmentation strategy, explaining how segmentations meant to strengthen brand identity differ from those capable of telling a company which markets it should enter and what goods to make. And they introduce their "gravity of decision spectrum", a tool that focuses on the form of consumer behavior that should be of the greatest interest to marketers--the importance that consumers place on a product or product category.

  17. Experimental replacement of esophagus with a short segment of trachea.

    Science.gov (United States)

    Abbasidezfouli, Azizollah; Ansari, Damoon; Sheikhy, Kambiz; Abarkar, Mohammad; Sadeghbeigi, Farahnaz; Abbasidezfouli, Sepehr; Sharifi, Davood

    2016-03-01

    Segmental resection of esophagus with primary anastomosis is prohibited because of the risk of dehiscence. We previously have shown that replacement of a segment of cervical esophagus with a tracheal segment of the same length could successfully be performed in a canine model. In this study, we sought to assess the feasibility of replacement of the esophageal defect with a shorter segment of trachea. In five mongrel dogs weighting 20-30 kg, under general anesthesia and after a cervical incision, 8 cm of the cervical esophagus was resected and replaced by a 4-cm segment of the adjacent trachea. The animals were evaluated clinically for signs and symptoms of stenosis and dehiscence and then euthanized after 2 mo of follow-up. All dogs recovered from surgery and started regular diet on the seventh postoperative day. No clinical or endoscopic sign of stenosis or voice change was seen. Squamous metaplasia and atrophy of mucosal glands and cartilage were detected in the histopathologic examination of the replaced segments. Replacement of a cervical esophageal defect with a shorter segment of trachea can be performed successfully in dogs. This procedure can be potentially used for the treatment of cervical esophageal lesions in humans. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Novel active contour model based on multi-variate local Gaussian distribution for local segmentation of MR brain images

    Science.gov (United States)

    Zheng, Qiang; Li, Honglun; Fan, Baode; Wu, Shuanhu; Xu, Jindong

    2017-12-01

    Active contour model (ACM) has been one of the most widely utilized methods in magnetic resonance (MR) brain image segmentation because of its ability of capturing topology changes. However, most of the existing ACMs only consider single-slice information in MR brain image data, i.e., the information used in ACMs based segmentation method is extracted only from one slice of MR brain image, which cannot take full advantage of the adjacent slice images' information, and cannot satisfy the local segmentation of MR brain images. In this paper, a novel ACM is proposed to solve the problem discussed above, which is based on multi-variate local Gaussian distribution and combines the adjacent slice images' information in MR brain image data to satisfy segmentation. The segmentation is finally achieved through maximizing the likelihood estimation. Experiments demonstrate the advantages of the proposed ACM over the single-slice ACM in local segmentation of MR brain image series.

  19. Scorpion image segmentation system

    Science.gov (United States)

    Joseph, E.; Aibinu, A. M.; Sadiq, B. A.; Bello Salau, H.; Salami, M. J. E.

    2013-12-01

    Death as a result of scorpion sting has been a major public health problem in developing countries. Despite the high rate of death as a result of scorpion sting, little report exists in literature of intelligent device and system for automatic detection of scorpion. This paper proposed a digital image processing approach based on the floresencing characteristics of Scorpion under Ultra-violet (UV) light for automatic detection and identification of scorpion. The acquired UV-based images undergo pre-processing to equalize uneven illumination and colour space channel separation. The extracted channels are then segmented into two non-overlapping classes. It has been observed that simple thresholding of the green channel of the acquired RGB UV-based image is sufficient for segmenting Scorpion from other background components in the acquired image. Two approaches to image segmentation have also been proposed in this work, namely, the simple average segmentation technique and K-means image segmentation. The proposed algorithm has been tested on over 40 UV scorpion images obtained from different part of the world and results obtained show an average accuracy of 97.7% in correctly classifying the pixel into two non-overlapping clusters. The proposed 1system will eliminate the problem associated with some of the existing manual approaches presently in use for scorpion detection.

  20. Automated design of degenerate codon libraries.

    Science.gov (United States)

    Mena, Marco A; Daugherty, Patrick S

    2005-12-01

    Degenerate codon libraries are frequently used in protein engineering and evolution studies but are often limited to targeting a small number of positions to adequately limit the search space. To mitigate this, codon degeneracy can be limited using heuristics or previous knowledge of the targeted positions. To automate design of libraries given a set of amino acid sequences, an algorithm (LibDesign) was developed that generates a set of possible degenerate codon libraries, their resulting size, and their score relative to a user-defined scoring function. A gene library of a specified size can then be constructed that is representative of the given amino acid distribution or that includes specific sequences or combinations thereof. LibDesign provides a new tool for automated design of high-quality protein libraries that more effectively harness existing sequence-structure information derived from multiple sequence alignment or computational protein design data.

  1. Atomic rate coefficients in a degenerate plasma

    Science.gov (United States)

    Aslanyan, Valentin; Tallents, Greg

    2015-11-01

    The electrons in a dense, degenerate plasma follow Fermi-Dirac statistics, which deviate significantly in this regime from the usual Maxwell-Boltzmann approach used by many models. We present methods to calculate the atomic rate coefficients for the Fermi-Dirac distribution and present a comparison of the ionization fraction of carbon calculated using both models. We have found that for densities close to solid, although the discrepancy is small for LTE conditions, there is a large divergence from the ionization fraction by using classical rate coefficients in the presence of strong photoionizing radiation. We have found that using these modified rates and the degenerate heat capacity may affect the time evolution of a plasma subject to extreme ultraviolet and x-ray radiation such as produced in free electron laser irradiation of solid targets.

  2. K-causality and degenerate spacetimes

    Science.gov (United States)

    Dowker, H. F.; Garcia, R. S.; Surya, S.

    2000-11-01

    The causal relation K+ was introduced by Sorkin and Woolgar to extend the standard causal analysis of C2 spacetimes to those that are only C0. Most of their results also hold true in the case of metrics with degeneracies which are C0 but vanish at isolated points. In this paper we seek to examine K+ explicitly in the case of topology-changing `Morse histories' which contain degeneracies. We first demonstrate some interesting features of this relation in globally Lorentzian spacetimes. In particular, we show that K+ is robust and the Hawking and Sachs characterization of causal continuity translates into a natural condition in terms of K+. We then examine K+ in topology-changing Morse spacetimes with the degenerate points excised and then for the Morse histories in which the degenerate points are reinstated. We find further characterizations of causal continuity in these cases.

  3. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Puget Sound and adjacent waters. 80.1395 Section 80.1395 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake Union...

  4. Early Verb Constructions in French: Adjacency on the Left Edge

    Science.gov (United States)

    Veneziano, Edy; Clark, Eve V.

    2016-01-01

    Children acquiring French elaborate their early verb constructions by adding adjacent morphemes incrementally at the left edge of core verbs. This hypothesis was tested with 2657 verb uses from four children between 1;3 and 2;7. Consistent with the Adjacency Hypothesis, children added clitic subjects frst only to present tense forms (as in…

  5. Objectifying the Adjacent and Opposite Angles: A Cultural Historical Analysis

    Science.gov (United States)

    Daher, Wajeeh; Musallam, Nadera

    2018-01-01

    The angle topic is central to the development of geometric knowledge. Two of the basic concepts associated with this topic are the adjacent and opposite angles. It is the goal of the present study to analyze, based on the cultural historical semiotics framework, how high-achieving seventh grade students objectify the adjacent and opposite angles'…

  6. On Pathos Adjacency Cut Vertex Jump Graph of a Tree

    OpenAIRE

    Nagesh.H.M; R.Chandrasekhar

    2014-01-01

    In this paper the concept of pathos adjacency cut vertex jump graph PJC(T) of a tree T is introduced. We also present a characterization of graphs whose pathos adjacency cut vertex jump graphs are planar, outerplanar, minimally non-outerplanar, Eulerian and Hamiltonian.

  7. Degenerate RFID Channel Modeling for Positioning Applications

    Directory of Open Access Journals (Sweden)

    A. Povalac

    2012-12-01

    Full Text Available This paper introduces the theory of channel modeling for positioning applications in UHF RFID. It explains basic parameters for channel characterization from both the narrowband and wideband point of view. More details are given about ranging and direction finding. Finally, several positioning scenarios are analyzed with developed channel models. All the described models use a degenerate channel, i.e. combined signal propagation from the transmitter to the tag and from the tag to the receiver.

  8. Degenerate odd Poisson bracket on Grassmann variables

    International Nuclear Information System (INIS)

    Soroka, V.A.

    2000-01-01

    A linear degenerate odd Poisson bracket (antibracket) realized solely on Grassmann variables is proposed. It is revealed that this bracket has at once three Grassmann-odd nilpotent Δ-like differential operators of the first, second and third orders with respect to the Grassmann derivatives. It is shown that these Δ-like operators, together with the Grassmann-odd nilpotent Casimir function of this bracket, form a finite-dimensional Lie superalgebra

  9. Immunology of age-related macular degeneration

    Science.gov (United States)

    Ambati, Jayakrishna; Atkinson, John P.; Gelfand, Bradley D.

    2014-01-01

    Age-related macular degeneration (AMD) is a leading cause of blindness in aged individuals. Recent advances have highlighted the essential role of immune processes in the development, progression and treatment of AMD. In this Review we discuss recent discoveries related to the immunological aspects of AMD pathogenesis. We outline the diverse immune cell types, inflammatory activators and pathways that are involved. Finally, we discuss the future of inflammation-directed therapeutics to treat AMD in the growing aged population. PMID:23702979

  10. Segmentation of complex document

    Directory of Open Access Journals (Sweden)

    Souad Oudjemia

    2014-06-01

    Full Text Available In this paper we present a method for segmentation of documents image with complex structure. This technique based on GLCM (Grey Level Co-occurrence Matrix used to segment this type of document in three regions namely, 'graphics', 'background' and 'text'. Very briefly, this method is to divide the document image, in block size chosen after a series of tests and then applying the co-occurrence matrix to each block in order to extract five textural parameters which are energy, entropy, the sum entropy, difference entropy and standard deviation. These parameters are then used to classify the image into three regions using the k-means algorithm; the last step of segmentation is obtained by grouping connected pixels. Two performance measurements are performed for both graphics and text zones; we have obtained a classification rate of 98.3% and a Misclassification rate of 1.79%.

  11. Degenerate pressure driven modified nucleus-acoustic waves in degenerate plasmas

    Science.gov (United States)

    Mamun, A. A.

    2018-02-01

    The existence of degenerate pressure driven modified nucleus-acoustic (DPDMNA) waves propagating in a cold degenerate quantum plasma (DQP) system [containing cold inertialess degenerate electron species (DES), cold inertial non-degenerate light nucleus species (LNS), and stationary heavy nucleus species (HNS)] is predicted for the first time. The DPDMNA waves (in which the mass density of the cold LNS provides the inertia and the cold inertialess DES gives rise to the restoring force) are new since they completely disappear if the degenerate pressure of the cold DES is neglected. It is found that the phase speed (Vp) of the DPDMNA waves decreases with the rise of the charge number density of the stationary HNS for both non-relativistic and ultra-relativistic DES, and that the ultra-relativistic DES does not have any effect on Vp when β = 1, where β = Λc/Λe with Λ e = ne 0 - 1 / 3 being the average inter-electron distance in the DQP system and Λc being the constant (˜10-10 cm) for the DES. However, the ultra-relativistic DES does have quite a significant effect on Vp for β ≫ 1 and β ≪ 1, and the ultra-relativistic effect significantly enhances (reduces) Vp for β ≫ 1 (β ≪ 1). The DPDMNA waves and their dispersion properties are expected to be useful in understanding the basic features of the electrostatic perturbation mode in space and laboratory DQP systems.

  12. Connecting textual segments

    DEFF Research Database (Denmark)

    Brügger, Niels

    2017-01-01

    history than just the years of the emergence of the web, the chapter traces the history of how segments of text have deliberately been connected to each other by the use of specific textual and media features, from clay tablets, manuscripts on parchment, and print, among others, to hyperlinks on stand......In “Connecting textual segments: A brief history of the web hyperlink” Niels Brügger investigates the history of one of the most fundamental features of the web: the hyperlink. Based on the argument that the web hyperlink is best understood if it is seen as another step in a much longer and broader...

  13. Unsupervised motion-based object segmentation refined by color

    Science.gov (United States)

    Piek, Matthijs C.; Braspenning, Ralph; Varekamp, Chris

    2003-06-01

    . The presented method has no problems with bifurcations. For the pixel resolution segmentation itself we reclassify pixels such that we optimize an error norm which favour similarly coloured regions and straight edges. SEGMENTATION MEASURE To assist in the evaluation of the proposed algorithm we developed a quality metric. Because the problem does not have an exact specification, we decided to define a ground truth output which we find desirable for a given input. We define the measure for the segmentation quality as being how different the segmentation is from the ground truth. Our measure enables us to evaluate oversegmentation and undersegmentation seperately. Also, it allows us to evaluate which parts of a frame suffer from oversegmentation or undersegmentation. The proposed algorithm has been tested on several typical sequences. CONCLUSIONS In this abstract we presented a new video segmentation method which performs well in the segmentation of multiple independently moving foreground objects from each other and the background. It combines the strong points of both colour and motion segmentation in the way we expected. One of the weak points is that the segmentation method suffers from undersegmentation when adjacent objects display similar motion. In sequences with detailed backgrounds the segmentation will sometimes display noisy edges. Apart from these results, we think that some of the techniques, and in particular the K-regions technique, may be useful for other two-dimensional data segmentation problems.

  14. Magnetotelluric Investigation in the Jiyang Depression and its Adjacent Areas

    Science.gov (United States)

    Zhang, L.; Hao, T.; Duan, Q.

    2008-12-01

    The Jiyang Depression is a secondary tectonic unit of the Bohai Bay Basin, and is a Mesozoic-Cenozoic continental-facie depositional depression. The Jiyang Depression consists of the Dongying, Zanhua, Chezhen, and Huimin sags, and the Yihezhuang, Chenjiazhuang, Qingcheng, Binxian, Guangrao, Shouguang, and heaves. In order to delineate shallow and deep structures of the depression, we conduct a magnetotelluric (MT) investigation in the Jiyang Depression and its adjacent areas. We use a remote reference setup to reduce noise disturbance, when several magnetotelluric sounding stations are measuring synchronously at different sites. The acquired MT data are to be processed and interpreted. We execute time series processing with the remote reference technique. The surveyed area is seriously interfered by noise. To improve quality of the data, we perform noise identification and manual selection of the time series segments. Identification of polarization modes is an important task for MT data qualitative interpretation. We apply for a PCA (principal component analysis) based method to automatically identify apparent polarized resistivity curves of TE and TM modes. The method recognizes the distortion and major variation of TE and TM curves and distinguishes the two kinds of curves with principal component analysis. From the apparent resistivity-frequency profile result, we can see that the Chenning Uplift and the Chenjiazhuang Heave reveal a 3-layered structure of medium-low-high, from the shallow to the deep. The structure is especially distinct for the Chenning Uplift, where there is a laterally steady-spreading high- resistivity zone corresponding to the frequency band lower than 1 Hz. The Dongying Sag is characteristic of high-low-medium from the shallow to the deep, and has a low-resistivity anomaly zone with obvious and wide lateral extending in the medium frequency band, which reflects that the deposition thickness of the basin is relatively big. The Guangrao

  15. Segmentation in cinema perception.

    Science.gov (United States)

    Carroll, J M; Bever, T G

    1976-03-12

    Viewers perceptually segment moving picture sequences into their cinematically defined units: excerpts that follow short film sequences are recognized faster when the excerpt originally came after a structural cinematic break (a cut or change in the action) than when it originally came before the break.

  16. Dictionary Based Image Segmentation

    DEFF Research Database (Denmark)

    Dahl, Anders Bjorholm; Dahl, Vedrana Andersen

    2015-01-01

    We propose a method for weakly supervised segmentation of natural images, which may contain both textured or non-textured regions. Our texture representation is based on a dictionary of image patches. To divide an image into separated regions with similar texture we use an implicit level sets...

  17. Unsupervised Image Segmentation

    Czech Academy of Sciences Publication Activity Database

    Haindl, Michal; Mikeš, Stanislav

    2014-01-01

    Roč. 36, č. 4 (2014), s. 23-23 R&D Projects: GA ČR(CZ) GA14-10911S Institutional support: RVO:67985556 Keywords : unsupervised image segmentation Subject RIV: BD - Theory of Information http://library.utia.cas.cz/separaty/2014/RO/haindl-0434412.pdf

  18. Metrics for image segmentation

    Science.gov (United States)

    Rees, Gareth; Greenway, Phil; Morray, Denise

    1998-07-01

    An important challenge in mapping image-processing techniques onto applications is the lack of quantitative performance measures. From a systems engineering perspective these are essential if system level requirements are to be decomposed into sub-system requirements which can be understood in terms of algorithm selection and performance optimization. Nowhere in computer vision is this more evident than in the area of image segmentation. This is a vigorous and innovative research activity, but even after nearly two decades of progress, it remains almost impossible to answer the question 'what would the performance of this segmentation algorithm be under these new conditions?' To begin to address this shortcoming, we have devised a well-principled metric for assessing the relative performance of two segmentation algorithms. This allows meaningful objective comparisons to be made between their outputs. It also estimates the absolute performance of an algorithm given ground truth. Our approach is an information theoretic one. In this paper, we describe the theory and motivation of our method, and present practical results obtained from a range of state of the art segmentation methods. We demonstrate that it is possible to measure the objective performance of these algorithms, and to use the information so gained to provide clues about how their performance might be improved.

  19. Human disc degeneration is associated with increased MMP 7 expression.

    Science.gov (United States)

    Le Maitre, C L; Freemont, A J; Hoyland, J A

    2006-01-01

    During intervertebral disc (IVD) degeneration, normal matrix synthesis decreases and degradation of disc matrix increases. A number of proteases that are increased during disc degeneration are thought to be involved in its pathogenesis. Matrix metalloproteinase 7 (MMP 7) (Matrilysin, PUMP-1) is known to cleave the major matrix molecules found within the IVD, i.e., the proteoglycan aggrecan and collagen type II. To date, however, it is not known how its expression changes with degeneration or its exact location. We investigated the localization of MMP 7 in human, histologically graded, nondegenerate, degenerated and prolapsed discs to ascertain whether MMP 7 is up-regulated during disc degeneration. Samples of human IVD tissue were fixed in neutral buffered formalin, embedded in paraffin, and sections stained with hematoxylin and eosin to score the degree of morphological degeneration. Immunohistochemistry was performed to localize MMP 7 in 41 human IVDs with varying degrees of degeneration. We found that the chondrocyte-like cells of the nucleus pulposus and inner annulus fibrosus were MMP 7 immunopositive; little immunopositivity was observed in the outer annulus. Nondegenerate discs showed few immunopositive cells. A significant increase in the proportion of MMP 7 immunopositive cells was seen in the nucleus pulposus of discs classified as showing intermediate levels of degeneration and a further increase was seen in discs with severe degeneration. Prolapsed discs showed more MMP 7 immunopositive cells compared to nondegenerated discs, but fewer than those seen in cases of severe degeneration.

  20. The comparative study of radiograph, MRI and pathology in degeneration of lumbar intervertebral disc

    International Nuclear Information System (INIS)

    Shang Tiesong; Wang Yunzhao

    2002-01-01

    Objective: To investigate the pathology, and MRI features of the degeneration of lumbar intervertebral discs (IVD). Methods: Thirteen human lumbar spine segments with 31 IVDs were harvested from fresh cadavers. High quality radiographs were taken for all specimens. Five segments with 20 IVD underwent MRl. Then, the radiographic and MRI findings were correlated with corresponding 87 pathologic sections. Results: Variant degeneration was observed in pathologic sections in all 31 IVDs. With MRI T 2 WI images, 20 IVDs showed linear and spotty high signal in the annular fibers, or most of the IVD showed high signal. On pathologic cuts, 22 of 31 IVDs showed infolding of annular fibers, 18 of 31 showed outfolding of annular fibers. On MRI T 1 WI and T 2 WI images, infolding and outfolding of annular fibers were seen as low signal. 20 of 31 IVDs had necrotic debris of cells in the nucleus pulposus. 14 of 20 demonstrated spotty low signal areas on MRI T 2 WI images. 7 Schmorl nodules were found. On pathologic sections Schmorl nodules were seen as IVD tissue protruding into vertebral endplates, they were seen as high signal on T 2 WI images. Two large fissures found on sections were seen as low signal on T 2 WI. Degenerative fibrosis seen on 6 IVD, which showed intermediate signal on T 2 WI images. However, radiographs only demonstrated osteophytes on 3 vertebrae, 7 Schmorl's nodules. Sclerotic, concave and irregular endplates were seen in 11 IVDs, the tatter is the indication of cartilaginous endplate disruption, Conclusion: MRI is very useful in demonstrating the degeneration of IVD, radiograph is able to indirectly show the disappearance of cartilaginous endplate

  1. Segmentation and clustering as complementary sources of information

    Science.gov (United States)

    Dale, Michael B.; Allison, Lloyd; Dale, Patricia E. R.

    2007-03-01

    This paper examines the effects of using a segmentation method to identify change-points or edges in vegetation. It identifies coherence (spatial or temporal) in place of unconstrained clustering. The segmentation method involves change-point detection along a sequence of observations so that each cluster formed is composed of adjacent samples; this is a form of constrained clustering. The protocol identifies one or more models, one for each section identified, and the quality of each is assessed using a minimum message length criterion, which provides a rational basis for selecting an appropriate model. Although the segmentation is less efficient than clustering, it does provide other information because it incorporates textural similarity as well as homogeneity. In addition it can be useful in determining various scales of variation that may apply to the data, providing a general method of small-scale pattern analysis.

  2. Lung tumor segmentation in PET images using graph cuts.

    Science.gov (United States)

    Ballangan, Cherry; Wang, Xiuying; Fulham, Michael; Eberl, Stefan; Feng, David Dagan

    2013-03-01

    The aim of segmentation of tumor regions in positron emission tomography (PET) is to provide more accurate measurements of tumor size and extension into adjacent structures, than is possible with visual assessment alone and hence improve patient management decisions. We propose a segmentation energy function for the graph cuts technique to improve lung tumor segmentation with PET. Our segmentation energy is based on an analysis of the tumor voxels in PET images combined with a standardized uptake value (SUV) cost function and a monotonic downhill SUV feature. The monotonic downhill feature avoids segmentation leakage into surrounding tissues with similar or higher PET tracer uptake than the tumor and the SUV cost function improves the boundary definition and also addresses situations where the lung tumor is heterogeneous. We evaluated the method in 42 clinical PET volumes from patients with non-small cell lung cancer (NSCLC). Our method improves segmentation and performs better than region growing approaches, the watershed technique, fuzzy-c-means, region-based active contour and tumor customized downhill. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Statistical characterization and segmentation of drusen in fundus images.

    Science.gov (United States)

    Santos-Villalobos, H; Karnowski, T P; Aykac, D; Giancardo, L; Li, Y; Nichols, T; Tobin, K W; Chaum, E

    2011-01-01

    Age related Macular Degeneration (AMD) is a disease of the retina associated with aging. AMD progression in patients is characterized by drusen, pigmentation changes, and geographic atrophy, which can be seen using fundus imagery. The level of AMD is characterized by standard scaling methods, which can be somewhat subjective in practice. In this work we propose a statistical image processing approach to segment drusen with the ultimate goal of characterizing the AMD progression in a data set of longitudinal images. The method characterizes retinal structures with a statistical model of the colors in the retina image. When comparing the segmentation results of the method between longitudinal images with known AMD progression and those without, the method detects progression in our longitudinal data set with an area under the receiver operating characteristics curve of 0.99.

  4. Statistical Characterization and Segmentation of Drusen in Fundus Images

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Villalobos, Hector J [ORNL; Karnowski, Thomas Paul [ORNL; Aykac, Deniz [ORNL; Giancardo, Luca [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK); Nichols, Trent L [ORNL; Tobin Jr, Kenneth William [ORNL; Chaum, Edward [University of Tennessee, Knoxville (UTK)

    2011-01-01

    Age related Macular Degeneration (AMD) is a disease of the retina associated with aging. AMD progression in patients is characterized by drusen, pigmentation changes, and geographic atrophy, which can be seen using fundus imagery. The level of AMD is characterized by standard scaling methods, which can be somewhat subjective in practice. In this work we propose a statistical image processing approach to segment drusen with the ultimate goal of characterizing the AMD progression in a data set of longitudinal images. The method characterizes retinal structures with a statistical model of the colors in the retina image. When comparing the segmentation results of the method between longitudinal images with known AMD progression and those without, the method detects progression in our longitudinal data set with an area under the receiver operating characteristics curve of 0.99.

  5. Genome instability: Linking ageing and brain degeneration.

    Science.gov (United States)

    Barzilai, Ari; Schumacher, Björn; Shiloh, Yosef

    2017-01-01

    Ageing is a multifactorial process affected by cumulative physiological changes resulting from stochastic processes combined with genetic factors, which together alter metabolic homeostasis. Genetic variation in maintenance of genome stability is emerging as an important determinant of ageing pace. Genome instability is also closely associated with a broad spectrum of conditions involving brain degeneration. Similarities and differences can be found between ageing-associated decline of brain functionality and the detrimental effect of genome instability on brain functionality and development. This review discusses these similarities and differences and highlights cell classes whose role in these processes might have been underestimated-glia and microglia. Copyright © 2016. Published by Elsevier B.V.

  6. Degenerate stars. XII - Recognition of hot nondegenerates

    Science.gov (United States)

    Greenstein, J. L.

    1980-12-01

    Fifty-one newly observed degenerate stars and 14 nondegenerates include 13 faint red stars, most of which do not show any lines except DF, Gr 554. Hot subdwarfs and an X-ray source are discussed along with the problem of low-resolution spectroscopic classification of dense hot stars. The multichannel spectrum of the carbon-rich magnetic star LP 790-29 is examined by fitting the undisturbed parts of the spectrum to a black body of 7625 K by the least squares method; the Swan bands absorb 600 A of the spectrum assuming that the blocked radiation is redistributed in the observed region.

  7. Aneutronic fusion in a degenerate plasma

    International Nuclear Information System (INIS)

    Son, S.; Fisch, N.J.

    2004-01-01

    In a Fermi-degenerate plasma, the electronic stopping of a slow ion is smaller than that given by the classical formula, because some transitions between the electron states are forbidden. The bremsstrahlung losses are then smaller, so that the nuclear burning of an aneutronic fuel is more efficient. Consequently, there occurs a parameter regime in which self-burning is possible. Practical obstacles in this regime that must be overcome before net energy can be realized include the compression of the fuel to an ultra dense state and the creation of a hot spot

  8. Aneutronic Fusion in a Degenerate Plasma

    International Nuclear Information System (INIS)

    Son, S.; Fisch, N.J.

    2004-01-01

    In a Fermi-degenerate plasma, the electronic stopping of a slow ion is smaller than that given by the classical formula, because some transitions between the electron states are forbidden. The bremsstrahlung losses are then smaller, so that the nuclear burning of an aneutronic fuel is more efficient. Consequently, there occurs a parameter regime in which self-burning is possible. Practical obstacles in this regime that must be overcome before net energy can be realized include the compression of the fuel to an ultra dense state and the creation of a hot spot

  9. Status of the segment interconnect, cable segment ancillary logic, and the cable segment hybrid driver projects

    International Nuclear Information System (INIS)

    Swoboda, C.; Barsotti, E.; Chappa, S.; Downing, R.; Goeransson, G.; Lensy, D.; Moore, G.; Rotolo, C.; Urish, J.

    1985-01-01

    The FASTBUS Segment Interconnect (SI) provides a communication path between two otherwise independent, asynchronous bus segments. In particular, the Segment Interconnect links a backplane crate segment to a cable segment. All standard FASTBUS address and data transactions can be passed through the SI or any number of SIs and segments in a path. Thus systems of arbitrary connection complexity can be formed, allowing simultaneous independent processing, yet still permitting devices associated with one segment to be accessed from others. The model S1 Segment Interconnect and the Cable Segment Ancillary Logic covered in this report comply with all the mandatory features stated in the FASTBUS specification document DOE/ER-0189. A block diagram of the SI is shown

  10. Community conservation adjacent to Ruaha National Park, Tanzania

    Science.gov (United States)

    Sue Stolberger

    2007-01-01

    In the areas adjacent to Ruaha National Park where rural communities exist, much more work and education is required to enable them to benefit directly and indirectly from tourism and managing their own natural resources.

  11. Influence of cantilevered sheet pile deflection on adjacent roadways.

    Science.gov (United States)

    2009-06-01

    Cantilevered sheet pile walls are often used adjacent roadways as temporary support during construction. Excess movement of these walls has led to excessive roadway distress causing additional repairs to be necessary. This study assessed the effects ...

  12. Suprabasalt stratigraphy within and adjacent to the reference repository location

    International Nuclear Information System (INIS)

    Bjornstad, B.N.

    1983-01-01

    This data-package contains six detailed stratigraphic correlations and structure cross sections of suprabasalt sediments in the area adjacent to and including the Reference Repository Location. 4 refs., 1 fig

  13. Sleeping sickness surveys: game reserve adjacent villages in Malawi

    African Journals Online (AJOL)

    Sleeping sickness surveys: game reserve adjacent villages in Malawi. ... Sera from 160 game ranger volunteers and from 82 suspected cases_of Rhodesian sleeping sickness were tested by use of ELISA, ... AJOL African Journals Online.

  14. MRI and MR tractography in bilateral hypertrophic olivary degeneration

    Directory of Open Access Journals (Sweden)

    Debraj Sen

    2014-01-01

    Full Text Available Hypertrophic olivary degeneration is a trans-synaptic neuronal degeneration associated with hypertrophy of the inferior olivary nucleus due to a lesion in the triangle of Guillain-Mollaret. Familiarity with this entity on magnetic resonance imaging (MRI is essential to avoid other erroneous ominous diagnoses. We present a case of bilateral hypertrophic olivary degeneration and discuss the etiopathogenesis and MRI findings in this entity. The contributory role of MR tractography in the diagnosis is also highlighted.

  15. MRI and MR tractography in bilateral hypertrophic olivary degeneration.

    Science.gov (United States)

    Sen, Debraj; Gulati, Yoginder S; Malik, Virender; Mohimen, Aneesh; Sibi, Eranki; Reddy, Deepak Chandra

    2014-10-01

    Hypertrophic olivary degeneration is a trans-synaptic neuronal degeneration associated with hypertrophy of the inferior olivary nucleus due to a lesion in the triangle of Guillain-Mollaret. Familiarity with this entity on magnetic resonance imaging (MRI) is essential to avoid other erroneous ominous diagnoses. We present a case of bilateral hypertrophic olivary degeneration and discuss the etiopathogenesis and MRI findings in this entity. The contributory role of MR tractography in the diagnosis is also highlighted.

  16. An Unusual Case of Extensive Lattice Degeneration and Retinal Detachment

    OpenAIRE

    Mathew, David J.; Sarma, Saurabh Kumar; Basaiawmoit, Jennifer V.

    2016-01-01

    Lattice degeneration of the retina is not infrequently encountered on a dilated retinal examination and many of them do not need any intervention. We report a case of atypical lattice degeneration variant with peripheral retinal detachment. An asymptomatic 35-year-old lady with minimal refractive error was found to have extensive lattice degeneration, peripheral retinal detachment and fibrotic changes peripherally with elevation of retinal vessels on dilated retinal examination. There were al...

  17. MRI and MR tractography in bilateral hypertrophic olivary degeneration

    International Nuclear Information System (INIS)

    Sen, Debraj; Gulati, Yoginder S.; Malik, Virender; Mohimen, Aneesh; Sibi, Eranki; Reddy, Deepak Chandra

    2014-01-01

    Hypertrophic olivary degeneration is a trans-synaptic neuronal degeneration associated with hypertrophy of the inferior olivary nucleus due to a lesion in the triangle of Guillain-Mollaret. Familiarity with this entity on magnetic resonance imaging (MRI) is essential to avoid other erroneous ominous diagnoses. We present a case of bilateral hypertrophic olivary degeneration and discuss the etiopathogenesis and MRI findings in this entity. The contributory role of MR tractography in the diagnosis is also highlighted

  18. Mutations in ABCR (ABCA4) in patients with Stargardt macular degeneration or cone-rod degeneration.

    Science.gov (United States)

    Briggs, C E; Rucinski, D; Rosenfeld, P J; Hirose, T; Berson, E L; Dryja, T P

    2001-09-01

    To determine the spectrum of ABCR mutations associated with Stargardt macular degeneration and cone-rod degeneration (CRD). One hundred eighteen unrelated patients with recessive Stargardt macular degeneration and eight with recessive CRD were screened for mutations in ABCR (ABCA4) by single-strand conformation polymorphism analysis. Variants were characterized by direct genomic sequencing. Segregation analysis was performed on the families of 20 patients in whom at least two or more likely pathogenic sequence changes were identified. The authors found 77 sequence changes likely to be pathogenic: 21 null mutations (15 novel), 55 missense changes (26 novel), and one deletion of a consensus glycosylation site (also novel). Fifty-two patients with Stargardt macular degeneration (44% of those screened) and five with CRD each had two of these sequence changes or were homozygous for one of them. Segregation analyses in the families of 19 of these patients were informative and revealed that the index cases and all available affected siblings were compound heterozygotes or homozygotes. The authors found one instance of an apparently de novo mutation, Ile824Thr, in a patient. Thirty-seven (31%) of the 118 patients with Stargardt disease and one with CRD had only one likely pathogenic sequence change. Twenty-nine patients with Stargardt disease (25%) and two with CRD had no identified sequence changes. This report of 42 novel mutations brings the growing number of identified likely pathogenic sequence changes in ABCR to approximately 250.

  19. Market segmentation: Venezuelan ADRs

    Directory of Open Access Journals (Sweden)

    Urbi Garay

    2012-12-01

    Full Text Available The control on foreign exchange imposed by Venezuela in 2003 constitute a natural experiment that allows researchers to observe the effects of exchange controls on stock market segmentation. This paper provides empirical evidence that although the Venezuelan capital market as a whole was highly segmented before the controls were imposed, the shares in the firm CANTV were, through their American Depositary Receipts (ADRs, partially integrated with the global market. Following the imposition of the exchange controls this integration was lost. Research also documents the spectacular and apparently contradictory rise experienced by the Caracas Stock Exchange during the serious economic crisis of 2003. It is argued that, as it happened in Argentina in 2002, the rise in share prices occurred because the depreciation of the Bolívar in the parallel currency market increased the local price of the stocks that had associated ADRs, which were negotiated in dollars.

  20. Scintillation counter, segmented shield

    International Nuclear Information System (INIS)

    Olson, R.E.; Thumim, A.D.

    1975-01-01

    A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into radiation-responsive areas. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (U.S.)

  1. Objectifying the adjacent and opposite angles: a cultural historical analysis

    Science.gov (United States)

    Daher, Wajeeh; Musallam, Nadera

    2018-02-01

    The angle topic is central to the development of geometric knowledge. Two of the basic concepts associated with this topic are the adjacent and opposite angles. It is the goal of the present study to analyze, based on the cultural historical semiotics framework, how high-achieving seventh grade students objectify the adjacent and opposite angles' concepts. We videoed the learning of a group of three high-achieving students who used technology, specifically GeoGebra, to explore geometric relations related to the adjacent and opposite angles' concepts. To analyze students' objectification of these concepts, we used the categories of objectification of knowledge (attention and awareness) and the categories of generalization (factual, contextual and symbolic), developed by Radford. The research results indicate that teacher's and students' verbal and visual signs, together with the software dynamic tools, mediated the students' objectification of the adjacent and opposite angles' concepts. Specifically, eye and gestures perceiving were part of the semiosis cycles in which the participating students were engaged and which related to the mathematical signs that signified the adjacent and the opposite angles. Moreover, the teacher's suggestions/requests/questions included/suggested semiotic signs/tools, including verbal signs that helped the students pay attention, be aware of and objectify the adjacent and opposite angles' concepts.

  2. Head segmentation in vertebrates

    OpenAIRE

    Kuratani, Shigeru; Schilling, Thomas

    2008-01-01

    Classic theories of vertebrate head segmentation clearly exemplify the idealistic nature of comparative embryology prior to the 20th century. Comparative embryology aimed at recognizing the basic, primary structure that is shared by all vertebrates, either as an archetype or an ancestral developmental pattern. Modern evolutionary developmental (Evo-Devo) studies are also based on comparison, and therefore have a tendency to reduce complex embryonic anatomy into overly simplified patterns. Her...

  3. Many-Body Green Function of Degenerate Systems

    International Nuclear Information System (INIS)

    Brouder, Christian; Panati, Gianluca; Stoltz, Gabriel

    2009-01-01

    A rigorous nonperturbative adiabatic approximation of the evolution operator in the many-body physics of degenerate systems is derived. This approximation is used to solve the long-standing problem of the choice of the initial states of H 0 leading to eigenstates of H 0 +V for degenerate systems. These initial states are eigenstates of P 0 VP 0 , where P 0 is the projection onto a degenerate eigenspace of H 0 . This result is used to give the proper definition of the Green function, the statistical Green function and the nonequilibrium Green function of degenerate systems. The convergence of these Green functions is established.

  4. The prognosis of retinal detachment due to lattice degeneration.

    Science.gov (United States)

    Benson, W E; Morse, P H

    1978-09-01

    In a series of 553 consecutive retinal detachments, 29% (120) were due to lattice degeneration. Forty-five percent of these were due to atrophic holes in the lattice degeneration and 55% were due to tears caused by traction posterior to or at the end of a patch of lattice. In phakic patients, retinal detachments due to atrophic holes were most common in young myopes. Detachments due to traction tears were seen in older, less myopic patients. The incidence of massive periretinal proliferation was less (5%) in detachments due to lattice degeneration than in detachments not due to lattice degeneration (6.5%).

  5. Video segmentation using keywords

    Science.gov (United States)

    Ton-That, Vinh; Vong, Chi-Tai; Nguyen-Dao, Xuan-Truong; Tran, Minh-Triet

    2018-04-01

    At DAVIS-2016 Challenge, many state-of-art video segmentation methods achieve potential results, but they still much depend on annotated frames to distinguish between background and foreground. It takes a lot of time and efforts to create these frames exactly. In this paper, we introduce a method to segment objects from video based on keywords given by user. First, we use a real-time object detection system - YOLOv2 to identify regions containing objects that have labels match with the given keywords in the first frame. Then, for each region identified from the previous step, we use Pyramid Scene Parsing Network to assign each pixel as foreground or background. These frames can be used as input frames for Object Flow algorithm to perform segmentation on entire video. We conduct experiments on a subset of DAVIS-2016 dataset in half the size of its original size, which shows that our method can handle many popular classes in PASCAL VOC 2012 dataset with acceptable accuracy, about 75.03%. We suggest widely testing by combining other methods to improve this result in the future.

  6. Market segmentation in behavioral perspective.

    OpenAIRE

    Wells, V.K.; Chang, S.W.; Oliveira-Castro, J.M.; Pallister, J.

    2010-01-01

    A segmentation approach is presented using both traditional demographic segmentation bases (age, social class/occupation, and working status) and a segmentation by benefits sought. The benefits sought in this case are utilitarian and informational reinforcement, variables developed from the Behavioral Perspective Model (BPM). Using data from 1,847 consumers and from a total of 76,682 individual purchases, brand choice and price and reinforcement responsiveness were assessed for each segment a...

  7. Getting superstring amplitudes by degenerating Riemann surfaces

    International Nuclear Information System (INIS)

    Matone, Marco; Volpato, Roberto

    2010-01-01

    We explicitly show how the chiral superstring amplitudes can be obtained through factorisation of the higher genus chiral measure induced by suitable degenerations of Riemann surfaces. This powerful tool also allows to derive, at any genera, consistency relations involving the amplitudes and the measure. A key point concerns the choice of the local coordinate at the node on degenerate Riemann surfaces that greatly simplifies the computations. As a first application, starting from recent ansaetze for the chiral measure up to genus five, we compute the chiral two-point function for massless Neveu-Schwarz states at genus two, three and four. For genus higher than three, these computations include some new corrections to the conjectural formulae appeared so far in the literature. After GSO projection, the two-point function vanishes at genus two and three, as expected from space-time supersymmetry arguments, but not at genus four. This suggests that the ansatz for the superstring measure should be corrected for genus higher than four.

  8. Metabolic anatomy of paraneoplastic cerebellar degeneration

    International Nuclear Information System (INIS)

    Anderson, N.E.; Posner, J.B.; Sidtis, J.J.; Moeller, J.R.; Strother, S.C.; Dhawan, V.; Rottenberg, D.A.

    1988-01-01

    Eleven patients with acquired cerebellar degeneration (10 of whom had paraneoplastic cerebellar degeneration [PCD]) were evaluated using neuropsychological tests and 18 F-fluorodeoxyglucose/positron emission tomography to (1) quantify motor, cognitive, and metabolic abnormalities; (2) determine if characteristic alterations in the regional cerebral metabolic rate for glucose (rCMRGlc) are associated with PCD; and (3) correlate behavioral and metabolic measures of disease severity. Eighteen volunteer subjects served as normal controls. Although some PCD neuropsychological test scores were abnormal, these results could not, in general, be dissociated from the effects of dysarthria and ataxia. rCMRGlc was reduced in patients with PCD (versus normal control subjects) in all regions except the brainstem. Analysis of patient and control rCMRGlc data using a mathematical model of regional metabolic interactions revealed two metabolic pattern descriptors, SSF1 and SSF2, which distinguished patients with PCD from normal control subjects; SSF2, which described a metabolic coupling between cerebellum, cuneus, and posterior temporal, lateral frontal, and paracentral cortex, correlated with quantitative indices of cerebellar dysfunction. Our inability to document substantial intellectual impairment in 7 of 10 patients with PCD contrasts with the 50% incidence of dementia in PCD reported by previous investigators. Widespread reductions in PCD rCMRGlc may result from the loss of cerebellar efferents to thalamus and forebrain structures, a reverse cerebellar diaschisis

  9. Progranulin in frontotemporal lobar degeneration and neuroinflammation

    Directory of Open Access Journals (Sweden)

    Hutton Michael L

    2007-02-01

    Full Text Available Abstract Progranulin (PGRN is a pleiotropic protein that has gained the attention of the neuroscience community with recent discoveries of mutations in the gene for PGRN that cause frontotemporal lobar degeneration (FTLD. Pathogenic mutations in PGRN result in null alleles, and the disease is likely the result of haploinsufficiency. Little is known about the normal function of PGRN in the central nervous system apart from a role in brain development. It is expressed by microglia and neurons. In the periphery, PGRN is involved in wound repair and inflammation. High PGRN expression has been associated with more aggressive growth of various tumors. The properties of full length PGRN are distinct from those of proteolytically derived peptides, referred to as granulins (GRNs. While PGRN has trophic properties, GRNs are more akin to inflammatory mediators such as cytokines. Loss of the neurotrophic properties of PGRN may play a role in selective neuronal degeneration in FTLD, but neuroinflammation may also be important. Gene expression studies suggest that PGRN is up-regulated in a variety of neuroinflammatory conditions, and increased PGRN expression by microglia may play a pivotal role in the response to brain injury, neuroinflammation and neurodegeneration.

  10. Observable consequences of partially degenerate leptogenesis

    CERN Document Server

    Ellis, Jonathan Richard; Yanagida, T; Ellis, John; Raidal, Martti

    2002-01-01

    In the context of the seesaw mechanism, it is natural that the large solar and atmospheric neutrino mixing angles originate separately from large 2 by 2 mixings in the neutrino and charged-lepton sectors, respectively, and large mixing in the neutrino couplings is in turn more plausible if two of the heavy singlet neutrinos are nearly degenerate. We study the phenomenology of this scenario, calculating leptogenesis by solving numerically the set of coupled Boltzmann equations for out-of-equilibrium heavy singlet neutrino decays in the minimal supersymmetric seesaw model. The near-degenerate neutrinos may weigh < 10^8 GeV, avoiding the cosmological gravitino problem. This scenario predicts that Br(mu to e gamma) should be strongly suppressed, because of the small singlet neutrino masses, whilst Br(tau to mu gamma) may be large enough to be observable in B-factory or LHC experiments. If the light neutrino masses are hierarchical, we predict that the neutrinoless double-beta decay parameter m_{ee} is approxim...

  11. MR imaging findings of hypertrophic olivary degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do Joong; Jeon, Pyung; Kim, Dong Ik [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

    1997-06-01

    To describe the magnetic resonance (MR) imaging findings of hypertrophic olivary degeneration (HOD) MR images of seven patients with HOD were retrospectively reviewed. Two were women and five were men, and they were aged between 48 and 65 (mean 58) years. Imaging examinations were performed with a 1.5-T unit, and the findings were used to evaluate the size and signal intensity of olivary lesions. The time interval from hemorrhagic ictus to MR imaging was between two and 30 months. Follow-up examinations were performed in two patients. All four patients with hemorrhages involving the central tegmental tract in the pons or midbrain showed ipsilateral HOD. Among these four, bilateral HOD was seen in one patient with hemorrhage involving the bilateral central tegmental tract, and in another with tegmental hemorrhage extending to the ipsilateral superior cerebellar peduncle. One patient with cerebellar hemorrhage involving the dentate nucleus had contralateral HOD. Two patients with multiple hemorrhages involving both the pons and cerebellum showed bilateral HOD. Axial MR images showed mild enlargement of the involved olivary mucleus, with high signal intensity on both proton density and T2 weighted images. There was no apparent enhancement on postcontrast T1-weighted images. MR imaging can clearly distinguish secondary olivary degeneration from underlying pathology involving the central tegmental tract in the pons or midbrain and cerebellum. These olivary abnormalities should not, however, be mistaken for primary medullary lesions.

  12. Vitreous in lattice degeneration of retina.

    Science.gov (United States)

    Foos, R Y; Simons, K B

    1984-05-01

    A localized pocket of missing vitreous invariably overlies lattice degeneration of the retina. Subjects with lattice also have a higher rate of rhegmatogenous retinal detachment, which is usually a complication of retinal tears. The latter are in turn a result of alterations in the central vitreous--that is, synchysis senilis leading to posterior vitreous detachment. In order to determine if there is either an association or a deleterious interaction between the local and central lesions of the vitreous in eyes with lattice, a comparison was made in autopsy eyes with and without lattice the degree of synchysis and rate of vitreous detachment. Results show no association between the local and central vitreous lesions, indicating that a higher rate of vitreous detachment is not the basis for the higher rate of retinal detachment in eyes with lattice. Also, there was no suggestion of deleterious interaction between the local and central vitreous lesions, either through vitreodonesis as a basis for precocious vitreous detachment, or through a greater degree of synchysis as a basis for interconnection of local and central lacunae (which could extend the localized retinal detachment in eyes with holes in lattice degeneration).

  13. MR imaging findings of hypertrophic olivary degeneration

    International Nuclear Information System (INIS)

    Kim, Do Joong; Jeon, Pyung; Kim, Dong Ik

    1997-01-01

    To describe the magnetic resonance (MR) imaging findings of hypertrophic olivary degeneration (HOD) MR images of seven patients with HOD were retrospectively reviewed. Two were women and five were men, and they were aged between 48 and 65 (mean 58) years. Imaging examinations were performed with a 1.5-T unit, and the findings were used to evaluate the size and signal intensity of olivary lesions. The time interval from hemorrhagic ictus to MR imaging was between two and 30 months. Follow-up examinations were performed in two patients. All four patients with hemorrhages involving the central tegmental tract in the pons or midbrain showed ipsilateral HOD. Among these four, bilateral HOD was seen in one patient with hemorrhage involving the bilateral central tegmental tract, and in another with tegmental hemorrhage extending to the ipsilateral superior cerebellar peduncle. One patient with cerebellar hemorrhage involving the dentate nucleus had contralateral HOD. Two patients with multiple hemorrhages involving both the pons and cerebellum showed bilateral HOD. Axial MR images showed mild enlargement of the involved olivary mucleus, with high signal intensity on both proton density and T2 weighted images. There was no apparent enhancement on postcontrast T1-weighted images. MR imaging can clearly distinguish secondary olivary degeneration from underlying pathology involving the central tegmental tract in the pons or midbrain and cerebellum. These olivary abnormalities should not, however, be mistaken for primary medullary lesions

  14. 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

  15. The Volpe Center GPS Adjacent Band Compatibility Program Plan : GPS Adjacent Band Compatibility Workshop, Volpe Center, Cambridge MA

    Science.gov (United States)

    2014-09-18

    Approach to DOT GPS Adjacent Band Compatibility Assessment. Identify forums and provide public outreach to make sure the progress and work are as open and transparent as possible. Develop an implementation plan that incorporates aspects from the DOT ...

  16. Segmenting the Adult Education Market.

    Science.gov (United States)

    Aurand, Tim

    1994-01-01

    Describes market segmentation and how the principles of segmentation can be applied to the adult education market. Indicates that applying segmentation techniques to adult education programs results in programs that are educationally and financially satisfying and serve an appropriate population. (JOW)

  17. Market Segmentation for Information Services.

    Science.gov (United States)

    Halperin, Michael

    1981-01-01

    Discusses the advantages and limitations of market segmentation as strategy for the marketing of information services made available by nonprofit organizations, particularly libraries. Market segmentation is defined, a market grid for libraries is described, and the segmentation of information services is outlined. A 16-item reference list is…

  18. Genetic and functional dissection of HTRA1 and LOC387715 in age-related macular degeneration.

    Directory of Open Access Journals (Sweden)

    Zhenglin Yang

    2010-02-01

    Full Text Available A common haplotype on 10q26 influences the risk of age-related macular degeneration (AMD and encompasses two genes, LOC387715 and HTRA1. Recent data have suggested that loss of LOC387715, mediated by an insertion/deletion (in/del that destabilizes its message, is causally related with the disorder. Here we show that loss of LOC387715 is insufficient to explain AMD susceptibility, since a nonsense mutation (R38X in this gene that leads to loss of its message resides in a protective haplotype. At the same time, the common disease haplotype tagged by the in/del and rs11200638 has an effect on the transcriptional upregulation of the adjacent gene, HTRA1. These data implicate increased HTRA1 expression in the pathogenesis of AMD and highlight the importance of exploring multiple functional consequences of alleles in haplotypes that confer susceptibility to complex traits.

  19. Oculomotor paralysis: 3D-CISS MR imaging with MPR in the evaluation of neuralgic manifestation and the adjacent structures

    Energy Technology Data Exchange (ETDEWEB)

    Sun Xiaoli; Liang Changhu [Shandong Medical Imaging Research Institute, Shandong University, Jing-wu Road No. 324, Jinan 250021 (China); Liu Cheng [Shandong Medical Imaging Research Institute, Shandong University, Jing-wu Road No. 324, Jinan 250021 (China)], E-mail: sdsxl2005@126.com; Liu Shuwei; Deng Kai; He Jingzhen [Shandong Medical Imaging Research Institute, Shandong University, Jing-wu Road No. 324, Jinan 250021 (China)

    2010-02-15

    Purpose: To evaluate the value of three-dimensional (3D) constructive interference in steady-state (CISS) magnetic resonance (MR) imaging with multi-planar reconstruction (MPR) in displaying the relationship between the oculomotor nerve and its adjacent structures for patients with oculomotor paralysis. Materials and methods: 17 consecutive patients with oculomotor paralysis were examined with 3D-CISS and conventional spin-echo (SE) sequences on a 1.5-Tesla MR system. Original transverse and MPR images were used for image interpretation. The features of the oculomotor nerve and its adjacent structures were identified. The diagnosis was surgically confirmed in all patients. Results: Through 3D-CISS with MPR images, obvious relationship of the oculomotor nerve and its adjacent structures was demonstrated on 17 patients. Of those oculomotor nerves, 15 were compressed by the arteries (n = 15), one by the craniopharyngioma (n = 1), and another one by the neurofibroma (n = 1). Conclusion: 3D-CISS MR imaging with MPR provides an excellent way to characterize the relationship between the nerve and its adjacent structures in the cisternal segment of the oculomotor nerve in the patients with oculomotor paralysis. Moreover, this method shows anatomical details for imaging diagnosis and surgical procedure.

  20. Oculomotor paralysis: 3D-CISS MR imaging with MPR in the evaluation of neuralgic manifestation and the adjacent structures

    International Nuclear Information System (INIS)

    Sun Xiaoli; Liang Changhu; Liu Cheng; Liu Shuwei; Deng Kai; He Jingzhen

    2010-01-01

    Purpose: To evaluate the value of three-dimensional (3D) constructive interference in steady-state (CISS) magnetic resonance (MR) imaging with multi-planar reconstruction (MPR) in displaying the relationship between the oculomotor nerve and its adjacent structures for patients with oculomotor paralysis. Materials and methods: 17 consecutive patients with oculomotor paralysis were examined with 3D-CISS and conventional spin-echo (SE) sequences on a 1.5-Tesla MR system. Original transverse and MPR images were used for image interpretation. The features of the oculomotor nerve and its adjacent structures were identified. The diagnosis was surgically confirmed in all patients. Results: Through 3D-CISS with MPR images, obvious relationship of the oculomotor nerve and its adjacent structures was demonstrated on 17 patients. Of those oculomotor nerves, 15 were compressed by the arteries (n = 15), one by the craniopharyngioma (n = 1), and another one by the neurofibroma (n = 1). Conclusion: 3D-CISS MR imaging with MPR provides an excellent way to characterize the relationship between the nerve and its adjacent structures in the cisternal segment of the oculomotor nerve in the patients with oculomotor paralysis. Moreover, this method shows anatomical details for imaging diagnosis and surgical procedure.

  1. Interactive segmentation for geographic atrophy in retinal fundus images.

    Science.gov (United States)

    Lee, Noah; Smith, R Theodore; Laine, Andrew F

    2008-10-01

    Fundus auto-fluorescence (FAF) imaging is a non-invasive technique for in vivo ophthalmoscopic inspection of age-related macular degeneration (AMD), the most common cause of blindness in developed countries. Geographic atrophy (GA) is an advanced form of AMD and accounts for 12-21% of severe visual loss in this disorder [3]. Automatic quantification of GA is important for determining disease progression and facilitating clinical diagnosis of AMD. The problem of automatic segmentation of pathological images still remains an unsolved problem. In this paper we leverage the watershed transform and generalized non-linear gradient operators for interactive segmentation and present an intuitive and simple approach for geographic atrophy segmentation. We compare our approach with the state of the art random walker [5] algorithm for interactive segmentation using ROC statistics. Quantitative evaluation experiments on 100 FAF images show a mean sensitivity/specificity of 98.3/97.7% for our approach and a mean sensitivity/specificity of 88.2/96.6% for the random walker algorithm.

  2. A Novel Approach of Cardiac Segmentation In CT Image Based On Spline Interpolation

    International Nuclear Information System (INIS)

    Gao Yuan; Ma Pengcheng

    2011-01-01

    Organ segmentation in CT images is the basis of organ model reconstruction, thus precisely detecting and extracting the organ boundary are keys for reconstruction. In CT image the cardiac are often adjacent to the surrounding tissues and gray gradient between them is too slight, which cause the difficulty of applying classical segmentation method. We proposed a novel algorithm for cardiac segmentation in CT images in this paper, which combines the gray gradient methods and the B-spline interpolation. This algorithm can perfectly detect the boundaries of cardiac, at the same time it could well keep the timeliness because of the automatic processing.

  3. Circummandibular Wires for Treatment of Dentoalveolar Fractures Adjacent to Edentulous Areas: A Report of Two Cases.

    Science.gov (United States)

    Maloney, Karl

    2015-09-01

    In general, dentoalveolar fractures are a common injury seen in emergency departments, dental offices, and oral and maxillofacial surgery practices. These injuries can be the result of direct trauma or indirect trauma. Direct trauma more often causes trauma to the maxillary dentition due to the exposure of the maxillary anterior teeth. Indirect trauma is usually the result of forced occlusion secondary to a blow to the chin or from a whiplash injury. Falls are the most common mechanism of injury seen in the pediatric group. In adolescents, many of these fractures are sustained during sporting activities. However, the use of mouth guards and other protective equipment has decreased this number. Most adult injuries are caused by motor vehicle accidents, contact sports, falls, bicycles, interpersonal violence, medical/dental mishaps, and industrial accidents. Early intervention to reduce and stabilize the fracture is required to establish a bony union and ensure correct function. Most dentoalveolar fractures have bilateral stable adjacent dentition and are treated with a closed technique utilizing an acid-etch/resin splint followed by splint removal at 4 weeks. Other inferior stabilization treatments used are arch bars and other wiring techniques. It is widely accepted that semirigid stabilization techniques, such as an acid-etch/resin splint or wiring procedures, are adequate to treat dentoalveolar fractures. This is in contrast to the treatment of mandible fractures where AO principles of rigid fixation are often followed. Fractures that are unable to be reduced sometimes necessitate an open reduction followed by internal fixation, sometimes using a secondary splint for mobile teeth. In those rare cases when there are not stable adjacent teeth bilaterally other modalities must be considered. In the present report, two cases are presented where circummandibular wires were used to treat fractured mandibular dentoalveolar segments adjacent to edentulous areas.

  4. Albedo estimation for scene segmentation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C H; Rosenfeld, A

    1983-03-01

    Standard methods of image segmentation do not take into account the three-dimensional nature of the underlying scene. For example, histogram-based segmentation tacitly assumes that the image intensity is piecewise constant, and this is not true when the scene contains curved surfaces. This paper introduces a method of taking 3d information into account in the segmentation process. The image intensities are adjusted to compensate for the effects of estimated surface orientation; the adjusted intensities can be regarded as reflectivity estimates. When histogram-based segmentation is applied to these new values, the image is segmented into parts corresponding to surfaces of constant reflectivity in the scene. 7 references.

  5. FRAMEWORK FOR COMPARING SEGMENTATION ALGORITHMS

    Directory of Open Access Journals (Sweden)

    G. Sithole

    2015-05-01

    Full Text Available The notion of a ‘Best’ segmentation does not exist. A segmentation algorithm is chosen based on the features it yields, the properties of the segments (point sets it generates, and the complexity of its algorithm. The segmentation is then assessed based on a variety of metrics such as homogeneity, heterogeneity, fragmentation, etc. Even after an algorithm is chosen its performance is still uncertain because the landscape/scenarios represented in a point cloud have a strong influence on the eventual segmentation. Thus selecting an appropriate segmentation algorithm is a process of trial and error. Automating the selection of segmentation algorithms and their parameters first requires methods to evaluate segmentations. Three common approaches for evaluating segmentation algorithms are ‘goodness methods’, ‘discrepancy methods’ and ‘benchmarks’. Benchmarks are considered the most comprehensive method of evaluation. This paper shortcomings in current benchmark methods are identified and a framework is proposed that permits both a visual and numerical evaluation of segmentations for different algorithms, algorithm parameters and evaluation metrics. The concept of the framework is demonstrated on a real point cloud. Current results are promising and suggest that it can be used to predict the performance of segmentation algorithms.

  6. Regional disc change in segmental hypoplasia of the lumbosacral vertebral bodies: MR findings

    International Nuclear Information System (INIS)

    Kim, Sung Kyu; Lee Seung Ro; Moon, Won Jin; Park, Dong Woo; Hahm, Chang Kok

    2000-01-01

    To classify types of vertebral hypoplasia and to investigate the prevalence and patterns of associated disc degeneration. Defining vertebral hypoplasia as occurring when the AP diameter of a lower vertebral body is smaller than that of an upper ones, we retrospectively reviewed the MR images obtained in 34 cases of this condition involving young adults. Two major types and two subtypes, a total of four different entities were classified as follows; type I: hypoplasia involving a single vertebral body; type II: hypoplasia involving serial lower segmental vertebral bodies; subtype a: hypoplastic body located anteriorly along the anterior spinal line; subtype b: hypoplastic body located posteriorly along the posterior spinal line. We also investigated each type of vertebral hypoplasia and patterns of associated disc changes. Three different types were observed. In type IIa (n=3D29), posterior disc occurred in 8/29 cases, diffuse degeneration in 21/29 patients, and posterior disc herniation in all. All type Ia cases (3/3) showed diffuse disc degeneration at both upper and lower disc levels, with posterior disc herniation, while both type IIb cases (2/2) showed diffuse disc degeneration, with bidirectional disc herniation. By identifying the exact patterns of vertebral hypoplasia, we were able to predict which portion of the disc was likely to degenerate. (author)

  7. Biochemical Measurements of Free Opsin in Macular Degeneration Eyes: Examining the 11-CIS Retinal Deficiency Hypothesis of Delayed Dark Adaptation (An American Ophthalmological Society Thesis).

    Science.gov (United States)

    Hanneken, Anne; Neikirk, Thomas; Johnson, Jennifer; Kono, Masahiro

    2017-08-01

    To test the hypothesis that delayed dark adaptation in patients with macular degeneration is due to an excess of free unliganded opsin (apo-opsin) and a deficiency of the visual chromophore, 11 -cis retinal, in rod outer segments. A total of 50 human autopsy eyes were harvested from donors with and without macular degeneration within 2-24 hrs. postmortem. Protocols were developed which permitted dark adaptation of normal human eyes after death and enucleation. Biochemical methods of purifying rod outer segments were optimized and the concentration of rhodopsin and apo-opsin was measured with UV-visible scanning spectroscopy. The presence of apo-opsin was calculated by measuring the difference in the rhodopsin absorption spectra before and after the addition of 11 -cis retinal. A total of 20 normal eyes and 16 eyes from donors with early, intermediate and advanced stages of macular degeneration were included in the final analysis. Dark adaptation was achieved by harvesting whole globes in low light, transferring into dark (light-proof) canisters and dissecting the globes using infrared light and image converters for visualization. Apo-opsin was readily detected in positive controls after the addition of 11 -cis retinal. Normal autopsy eyes showed no evidence of apo-opsin. Eyes with macular degeneration also showed no evidence of apo-opsin, regardless of the severity of disease. Methods have been developed to study dark adaptation in human autopsy eyes. Eyes with age-related macular degeneration do not show a deficiency of 11 -cis retinal or an excess of apo-opsin within rod outer segments.

  8. An Improved Random Walker with Bayes Model for Volumetric Medical Image Segmentation

    Directory of Open Access Journals (Sweden)

    Chunhua Dong

    2017-01-01

    Full Text Available Random walk (RW method has been widely used to segment the organ in the volumetric medical image. However, it leads to a very large-scale graph due to a number of nodes equal to a voxel number and inaccurate segmentation because of the unavailability of appropriate initial seed point setting. In addition, the classical RW algorithm was designed for a user to mark a few pixels with an arbitrary number of labels, regardless of the intensity and shape information of the organ. Hence, we propose a prior knowledge-based Bayes random walk framework to segment the volumetric medical image in a slice-by-slice manner. Our strategy is to employ the previous segmented slice to obtain the shape and intensity knowledge of the target organ for the adjacent slice. According to the prior knowledge, the object/background seed points can be dynamically updated for the adjacent slice by combining the narrow band threshold (NBT method and the organ model with a Gaussian process. Finally, a high-quality image segmentation result can be automatically achieved using Bayes RW algorithm. Comparing our method with conventional RW and state-of-the-art interactive segmentation methods, our results show an improvement in the accuracy for liver segmentation (p<0.001.

  9. A dam for retrograde axonal degeneration in multiple sclerosis?

    NARCIS (Netherlands)

    Balk, L.J.; Twisk, J.W.R.; Steenwijk, M.D.; Daams, M.; Tewarie, P.; Killestein, J.; Uitdehaag, B.M.J.; Polman, C.H.; Petzold, A.F.S.

    2014-01-01

    Objective: Trans-synaptic axonal degeneration is a mechanism by which neurodegeneration can spread from a sick to a healthy neuron in the central nervous system. This study investigated to what extent trans-synaptic axonal degeneration takes place within the visual pathway in multiple sclerosis

  10. 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.

  11. Lattice degeneration of the retina and retinal detachment.

    Science.gov (United States)

    Semes, L P

    1992-01-01

    Lattice retinal degeneration is considered the most significant peripheral retinal disorder potentially predisposing to retinal breaks and retinal detachment. Lattice degeneration affects the vitreous and inner retinal layers with secondary changes as deep as the retinal pigment epithelium and perhaps the choriocapillaris. Variations in clinical appearance are the rule; geographically, lattice lesions favor the vertical meridians between the equator and the ora serrata. Lattice degeneration begins early in life and has been reported in sequential generations of the same family. Along with its customary bilateral occurrence, lattice shares other characteristics of a dystrophy. The association between the vitreous and retina in lattice lesions may be responsible for the majority of lattice-induced retinal detachments. The tumultuous event of posterior vitreous separation in the presence of abnormally strong vitreoretinal adherence is the trigger for a retinal tear that, in turn, may lead to retinal detachment. Although retinal holes in young patients with lattice degeneration may play a role in the evolution of retinal detachment, the clinical course of lattice degeneration seems to be one of dormancy rather than of progressive change. This discussion outlines the pathophysiology of lattice retinal degeneration and the relationship of pathophysiology to clinical presentation. The epidemiology of lattice degeneration is summarized, as are the possible precursors to retinal detachment. A clinical characterization of the natural history of lattice degeneration is offered, and interventions for complications are described. To conclude, management strategies from a primary-care standpoint are reviewed.

  12. Prevalence of age-related macular degeneration in elderly Caucasians

    DEFF Research Database (Denmark)

    Erke, Maja G; Bertelsen, Geir; Peto, Tunde

    2012-01-01

    To describe the sex- and age-specific prevalence of drusen, geographic atrophy, and neovascular age-related macular degeneration (AMD).......To describe the sex- and age-specific prevalence of drusen, geographic atrophy, and neovascular age-related macular degeneration (AMD)....

  13. Optical Coherence Tomography of Retinal Degeneration in Royal College of Surgeons Rats and Its Correlation with Morphology and Electroretinography.

    Directory of Open Access Journals (Sweden)

    Kobu Adachi

    Full Text Available To evaluate the correlation between optical coherence tomography (OCT and the histological, ultrastructural and electroretinography (ERG findings of retinal degeneration in Royal College of Surgeons (RCS-/- rats.Using OCT, we qualitatively and quantitatively observed the continual retinal degeneration in RCS-/- rats, from postnatal (PN day 17 until PN day 111. These findings were compared with the corresponding histological, electron microscopic, and ERG findings. We also compared them to OCT findings in wild type RCS+/+ rats, which were used as controls.After PN day 17, the hyperreflective band at the apical side of the photoreceptor layer became blurred. The inner segment (IS ellipsoid zone then became obscured, and the photoreceptor IS and outer segment (OS layers became diffusely hyperreflective after PN day 21. These changes correlated with histological and electron microscopic findings showing extracellular lamellar material that accumulated in the photoreceptor OS layer. After PN day 26, the outer nuclear layer became significantly thinner (P < 0.01 and hyperreflective compared with that in the controls; conversely, the photoreceptor IS and OS layers, as well as the inner retinal layers, became significantly thicker (P < 0.001 and P = 0.05, respectively. The apical hyperreflective band, as well as the IS ellipsoid zone, gradually disappeared between PN day 20 and PN day 30; concurrently, the ERG a- and b-wave amplitudes deteriorated. In contrast, the thicknesses of the combined retinal pigment epithelium and choroid did not differ significantly between RCS-/- and RCS+/+ rats.Our results suggest that OCT demonstrates histologically validated photoreceptor degeneration in RCS rats, and that OCT findings partly correlate with ERG findings. We propose that OCT is a less invasive and useful method for evaluating photoreceptor degeneration in animal models of retinitis pigmentosa.

  14. Image segmentation by hierarchial agglomeration of polygons using ecological statistics

    Science.gov (United States)

    Prasad, Lakshman; Swaminarayan, Sriram

    2013-04-23

    A method for rapid hierarchical image segmentation based on perceptually driven contour completion and scene statistics is disclosed. The method begins with an initial fine-scale segmentation of an image, such as obtained by perceptual completion of partial contours into polygonal regions using region-contour correspondences established by Delaunay triangulation of edge pixels as implemented in VISTA. The resulting polygons are analyzed with respect to their size and color/intensity distributions and the structural properties of their boundaries. Statistical estimates of granularity of size, similarity of color, texture, and saliency of intervening boundaries are computed and formulated into logical (Boolean) predicates. The combined satisfiability of these Boolean predicates by a pair of adjacent polygons at a given segmentation level qualifies them for merging into a larger polygon representing a coarser, larger-scale feature of the pixel image and collectively obtains the next level of polygonal segments in a hierarchy of fine-to-coarse segmentations. The iterative application of this process precipitates textured regions as polygons with highly convolved boundaries and helps distinguish them from objects which typically have more regular boundaries. The method yields a multiscale decomposition of an image into constituent features that enjoy a hierarchical relationship with features at finer and coarser scales. This provides a traversable graph structure from which feature content and context in terms of other features can be derived, aiding in automated image understanding tasks. The method disclosed is highly efficient and can be used to decompose and analyze large images.

  15. Negative electroretinograms in pericentral pigmentary retinal degeneration.

    Science.gov (United States)

    Hotta, Kazuki; Kondo, Mineo; Nakamura, Makoto; Hotta, Junko; Terasaki, Hiroko; Miyake, Yozo; Hida, Tetsuo

    2006-01-01

    The clinical presentation and electrophysiological findings are described of three consecutive cases with pericentral pigmentary retinal degeneration. The responses to bright flashes after dark adaptation showed negative waveform shape in all cases. Rod responses were strongly reduced compared with cone responses. Cone electroretinograms elicited by long-duration stimuli showed greater loss of the on-response than the off-response. The ratio of the on-response amplitude to off-response amplitude of these patients (0.52 +/- 0.12; mean +/- SD, n = 6) was significantly smaller than that of normal subject (0.83 +/- 0.21; mean +/- SD, n = 8) (Mann-Whitney U-test, P retinal function, especially in transmission between photoreceptors and depolarizing bipolar cells.

  16. Tidal effects in twin-degenerate binaries

    International Nuclear Information System (INIS)

    Campbell, C.G.

    1984-01-01

    The tidal velocity field is calculated for an initially non-rotating low mass white dwarf secondary in a twin-degenerate binary. These motions are used to find the tidal torque on the secondary, to first order in the orbital frequency, and an expression is derived for the synchronization time. For a lobe-filling secondary the synchronization time has a weak dependence on the mass and luminosity of the star, and for the binary G61-29 is found to be of the same order as the estimated lifetime of the system. It is emphasized, however, that tidal excitation of non-radial oscillatory modes in the secondary may significantly shorten the synchronization time. (author)

  17. A COMPUTATIONAL MODEL OF MOTOR NEURON DEGENERATION

    Science.gov (United States)

    Le Masson, Gwendal; Przedborski, Serge; Abbott, L.F.

    2014-01-01

    SUMMARY To explore the link between bioenergetics and motor neuron degeneration, we used a computational model in which detailed morphology and ion conductance are paired with intracellular ATP production and consumption. We found that reduced ATP availability increases the metabolic cost of a single action potential and disrupts K+/Na+ homeostasis, resulting in a chronic depolarization. The magnitude of the ATP shortage at which this ionic instability occurs depends on the morphology and intrinsic conductance characteristic of the neuron. If ATP shortage is confined to the distal part of the axon, the ensuing local ionic instability eventually spreads to the whole neuron and involves fasciculation-like spiking events. A shortage of ATP also causes a rise in intracellular calcium. Our modeling work supports the notion that mitochondrial dysfunction can account for salient features of the paralytic disorder amyotrophic lateral sclerosis, including motor neuron hyperexcitability, fasciculation, and differential vulnerability of motor neuron subpopulations. PMID:25088365

  18. A computational model of motor neuron degeneration.

    Science.gov (United States)

    Le Masson, Gwendal; Przedborski, Serge; Abbott, L F

    2014-08-20

    To explore the link between bioenergetics and motor neuron degeneration, we used a computational model in which detailed morphology and ion conductance are paired with intracellular ATP production and consumption. We found that reduced ATP availability increases the metabolic cost of a single action potential and disrupts K+/Na+ homeostasis, resulting in a chronic depolarization. The magnitude of the ATP shortage at which this ionic instability occurs depends on the morphology and intrinsic conductance characteristic of the neuron. If ATP shortage is confined to the distal part of the axon, the ensuing local ionic instability eventually spreads to the whole neuron and involves fasciculation-like spiking events. A shortage of ATP also causes a rise in intracellular calcium. Our modeling work supports the notion that mitochondrial dysfunction can account for salient features of the paralytic disorder amyotrophic lateral sclerosis, including motor neuron hyperexcitability, fasciculation, and differential vulnerability of motor neuron subpopulations. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Degenerate R-S perturbation theory

    Science.gov (United States)

    Hirschfelder, J. O.; Certain, P. R.

    1973-01-01

    A concise, systematic procedure is given for determining the Rayleigh-Schrodinger energies and wave functions of degenerate states to arbitrarily high orders even when the degeneracies of the various states are resolved in arbitrary orders. The procedure is expressed in terms of an iterative cycle in which the energy through the (2n+1)st order is expressed in terms of the partially determined wave function through the n-th order. Both a direct and an operator derivation are given. The two approaches are equivalent and can be transcribed into each other. The direct approach deals with the wave functions (without the use of formal operators) and has the advantage that it resembles the usual treatment of nondegenerate perturbations and maintains close contact with the basic physics. In the operator approach, the wave functions are expressed in terms of infinite order operators which are determined by the successive resolution of the space of the zeroth order functions.

  20. Nearly degenerate neutrinos, supersymmetry and radiative corrections

    International Nuclear Information System (INIS)

    Casas, J.A.; Espinosa, J.R.; Ibarra, A.; Navarro, I.

    2000-01-01

    If neutrinos are to play a relevant cosmological role, they must be essentially degenerate with a mass matrix of the bimaximal mixing type. We study this scenario in the MSSM framework, finding that if neutrino masses are produced by a see-saw mechanism, the radiative corrections give rise to mass splittings and mixing angles that can accommodate the atmospheric and the (large angle MSW) solar neutrino oscillations. This provides a natural origin for the Δm 2 sol 2 atm hierarchy. On the other hand, the vacuum oscillation solution to the solar neutrino problem is always excluded. We discuss also in the SUSY scenario other possible effects of radiative corrections involving the new neutrino Yukawa couplings, including implications for triviality limits on the Majorana mass, the infrared fixed point value of the top Yukawa coupling, and gauge coupling and bottom-tau unification

  1. Prevention of age-related macular degeneration.

    Science.gov (United States)

    Wong, Ian Yat Hin; Koo, Simon Chi Yan; Chan, Clement Wai Nang

    2011-02-01

    Age-related macular degeneration (AMD) is one of the leading causes of blindness in the developed world. Although effective treatment modalities such as anti-VEGF treatment have been developed for neovascular AMD, there is still no effective treatment for geographical atrophy, and therefore the most cost-effective management of AMD is to start with prevention. This review looks at current evidence on preventive measures targeted at AMD. Modalities reviewed include (1) nutritional supplements such as the Age-Related Eye Disease Study (AREDS) formula, lutein and zeaxanthin, omega-3 fatty acid, and berry extracts, (2) lifestyle modifications, including smoking and body-mass-index, and (3) filtering sunlight, i.e. sunglasses and blue-blocking intraocular lenses. In summary, the only proven effective preventive measures are stopping smoking and the AREDS formula.

  2. Progression of Fatty Muscle Degeneration in Atraumatic Rotator Cuff Tears.

    Science.gov (United States)

    Hebert-Davies, Jonah; Teefey, Sharlene A; Steger-May, Karen; Chamberlain, Aaron M; Middleton, William; Robinson, Kathryn; Yamaguchi, Ken; Keener, Jay D

    2017-05-17

    The purpose of this prospective study was to examine the progression of fatty muscle degeneration over time in asymptomatic shoulders with degenerative rotator cuff tears. Subjects with an asymptomatic rotator cuff tear in 1 shoulder and pain due to rotator cuff disease in the contralateral shoulder were enrolled in a prospective cohort. Subjects were followed annually with shoulder ultrasonography, which evaluated tear size, location, and fatty muscle degeneration. Tears that were either full-thickness at enrollment or progressed to a full-thickness defect during follow-up were examined. A minimum follow-up of 2 years was necessary for eligibility. One hundred and fifty-six shoulders with full-thickness rotator cuff tears were potentially eligible. Seventy shoulders had measurable fatty muscle degeneration of at least 1 rotator cuff muscle at some time point. Patients with fatty muscle degeneration in the shoulder were older than those without degeneration (mean, 65.8 years [95% confidence interval (CI), 64.0 to 67.6 years] compared with 61.0 years [95% CI, 59.1 to 62.9 years]; p tears at baseline was larger in shoulders with degeneration than in shoulders that did not develop degeneration (13 and 10 mm wide, respectively, and 13 and 10 mm long; p Tears with fatty muscle degeneration were more likely to have enlarged during follow-up than were tears that never developed muscle degeneration (79% compared with 58%; odds ratio, 2.64 [95% CI, 1.29 to 5.39]; p muscle degeneration occurred more frequently in shoulders with tears that had enlarged (43%; 45 of 105) than in shoulders with tears that had not enlarged (20%; 10 of 51; p tears with enlargement and progression of muscle degeneration were more likely to extend into the anterior supraspinatus than were those without progression (53% and 17%, respectively; p tear size (p = 0.56). The median time from tear enlargement to progression of fatty muscle degeneration was 1.0 year (range, -2.0 to 6.9 years) for the

  3. Formation of Degenerate Band Gaps in Layered Systems

    Directory of Open Access Journals (Sweden)

    Alexey P. Vinogradov

    2012-06-01

    Full Text Available In the review, peculiarities of spectra of one-dimensional photonic crystals made of anisotropic and/or magnetooptic materials are considered. The attention is focused on band gaps of a special type—the so called degenerate band gaps which are degenerate with respect to polarization. Mechanisms of formation and properties of these band gaps are analyzed. Peculiarities of spectra of photonic crystals that arise due to the linkage between band gaps are discussed. Particularly, it is shown that formation of a frozen mode is caused by linkage between Brillouin and degenerate band gaps. Also, existence of the optical Borrmann effect at the boundaries of degenerate band gaps and optical Tamm states at the frequencies of degenerate band gaps are analyzed.

  4. [Lattice degeneration of the peripheral retina: ultrastructural study].

    Science.gov (United States)

    Bec, P; Malecaze, F; Arne, J L; Mathis, A

    1985-01-01

    The ultrastructural study of a case of snail track degeneration shows the presence of lipid inclusions in both the glial and the macrophage cells in every layer of the retina, and the existence of intraretinal fibers different from collagen fibers appearing to be glial filaments similar to those found in astrocytic gliomes and to the Rosenthal fibers observed in senile nervous cells. Other features were thinning of the retina and absence of blood vessels in the retina. There are no abnormalities of the vitreo-retinal juncture. All the lesions are in agreement with those observed by Daicker [Ophthalmologica, Basel 165: 360-365, 1972; Klin. Mbl. Augenheilk. 172: 581-583, 1978] with some differences, however. They are different from those found in lattice degeneration. They show that snail track degeneration is a specific form of peripheral retinal degeneration which is quite different from lattice degeneration and must not be considered similar.

  5. Segmental in vivo vertebral kinematics at the walk, trot and canter: a preliminary study.

    Science.gov (United States)

    Haussler, K K; Bertram, J E; Gellman, K; Hermanson, J W

    2001-04-01

    Understanding the pathophysiology of equine back problems, for clinical evaluation, treatment or injury prevention, requires understanding of the normal 3-dimensional motion characteristics of the vertebral column. Recent studies have investigated regional vertebral kinematics; however, there are no reported measures of direct in vivo segmental vertebral kinematics in exercising horses. Relative movements between 2 adjacent vertebrae were recorded for 3 horses that were clinically sound and did not have a known history of a back problem. A transducer consisting of 2 fixtures and an array of liquid metal strain gauges (LMSGs) was used to measure 3-dimensional segmental vertebral motion. The transducer was attached directly to Steinmann pins implanted in the dorsal spinous processes of adjacent vertebrae in 3 vertebral regions: thoracic (T14 to T16), lumbar (L1 to L3) and lumbosacral (L6 to S2). Rotational displacements between adjacent vertebrae were calculated from the differential outputs of the LMSG array during walk, trot and canter on a treadmill. Peak magnitudes of dorsoventral flexion, lateral bending and axial rotation were recorded continuously for each stride. The largest motion of the 3 instrumented vertebral segments was at the lumbosacral junction. In general, the greatest magnitude of segmental vertebral motion occurred during the canter and the least during the trot. The dynamic and continuous measure of 3-dimensional in vivo segmental vertebral motion provides an important new perspective for evaluating vertebral motion and back problems in horses.

  6. Sea-floor drainage features of Cascadia Basin and the adjacent continental slope, northeast Pacific Ocean

    Science.gov (United States)

    Hampton, M.A.; Karl, Herman A.; Kenyon, Neil H.

    1989-01-01

    Sea-floor drainage features of Cascadia Basin and the adjacent continental slope include canyons, primary fan valleys, deep-sea valleys, and remnant valley segments. Long-range sidescan sonographs and associated seismic-reflection profiles indicate that the canyons may originate along a mid-slope escarpment and grow upslope by mass wasting and downslope by valley erosion or aggradation. Most canyons are partly filled with sediment, and Quillayute Canyon is almost completely filled. Under normal growth conditions, the larger canyons connect with primary fan valleys or deep-sea valleys in Cascadia Basin, but development of accretionary ridges blocks or re-routes most canyons, forcing abandonment of the associated valleys in the basin. Astoria Fan has a primary fan valley that connects with Astoria Canyon at the fan apex. The fan valley is bordered by parallel levees on the upper fan but becomes obscure on the lower fan, where a few valley segments appear on the sonographs. Apparently, Nitinat Fan does not presently have a primary fan valley; none of the numerous valleys on the fan connect with a canyon. The Willapa-Cascadia-Vancouver-Juan de Fuca deep-sea valley system bypasses the submarine fans and includes deeply incised valleys to broad shallow swales, as well as within-valley terraces and hanging-valley confluences. ?? 1989.

  7. Optimally segmented magnetic structures

    DEFF Research Database (Denmark)

    Insinga, Andrea Roberto; Bahl, Christian; Bjørk, Rasmus

    We present a semi-analytical algorithm for magnet design problems, which calculates the optimal way to subdivide a given design region into uniformly magnetized segments.The availability of powerful rare-earth magnetic materials such as Nd-Fe-B has broadened the range of applications of permanent...... is not available.We will illustrate the results for magnet design problems from different areas, such as electric motors/generators (as the example in the picture), beam focusing for particle accelerators and magnetic refrigeration devices.......We present a semi-analytical algorithm for magnet design problems, which calculates the optimal way to subdivide a given design region into uniformly magnetized segments.The availability of powerful rare-earth magnetic materials such as Nd-Fe-B has broadened the range of applications of permanent...... magnets[1][2]. However, the powerful rare-earth magnets are generally expensive, so both the scientific and industrial communities have devoted a lot of effort into developing suitable design methods. Even so, many magnet optimization algorithms either are based on heuristic approaches[3...

  8. Hybrid dynamic stabilization: a biomechanical assessment of adjacent and supraadjacent levels of the lumbar spine.

    Science.gov (United States)

    Mageswaran, Prasath; Techy, Fernando; Colbrunn, Robb W; Bonner, Tara F; McLain, Robert F

    2012-09-01

    The object of this study was to evaluate the effect of hybrid dynamic stabilization on adjacent levels of the lumbar spine. Seven human spine specimens from T-12 to the sacrum were used. The following conditions were implemented: 1) intact spine; 2) fusion of L4-5 with bilateral pedicle screws and titanium rods; and 3) supplementation of the L4-5 fusion with pedicle screw dynamic stabilization constructs at L3-4, with the purpose of protecting the L3-4 level from excessive range of motion (ROM) and to create a smoother motion transition to the rest of the lumbar spine. An industrial robot was used to apply continuous pure moment (± 2 Nm) in flexion-extension with and without a follower load, lateral bending, and axial rotation. Intersegmental rotations of the fused, dynamically stabilized, and adjacent levels were measured and compared. In flexion-extension only, the rigid instrumentation at L4-5 caused a 78% decrease in the segment's ROM when compared with the intact specimen. To compensate, it caused an increase in motion at adjacent levels L1-2 (45.6%) and L2-3 (23.2%) only. The placement of the dynamic construct at L3-4 decreased the operated level's ROM by 80.4% (similar stability as the fusion at L4-5), when compared with the intact specimen, and caused a significant increase in motion at all tested adjacent levels. In flexion-extension with a follower load, instrumentation at L4-5 affected only a subadjacent level, L5-sacrum (52.0%), while causing a reduction in motion at the operated level (L4-5, -76.4%). The dynamic construct caused a significant increase in motion at the adjacent levels T12-L1 (44.9%), L1-2 (57.3%), and L5-sacrum (83.9%), while motion at the operated level (L3-4) was reduced by 76.7%. In lateral bending, instrumentation at L4-5 increased motion at only T12-L1 (22.8%). The dynamic construct at L3-4 caused an increase in motion at T12-L1 (69.9%), L1-2 (59.4%), L2-3 (44.7%), and L5-sacrum (43.7%). In axial rotation, only the placement of

  9. Emission of pesticides during drilling and deposition in adjacent areas

    Directory of Open Access Journals (Sweden)

    Heimbach, Udo

    2014-02-01

    Full Text Available In seven experiments seeds of maize, oil seed rape and barley, treated with neonicotinoids, were sown using pneumatic drilling equipment with deflectors attached in case of pneumatic suction systems. Directly adjacent to the drilled area of usually about 50 m width were replicated areas with bare soil as well as with crops. During maize (Zea mays drilling flowering oil seed rape (Brassica napus and during drilling of barley (Hordeum vulgare and oil seed rape flowering white mustard (Sinapis alba was adjacent. The amount of residues in the adjacent non crop areas in Petri dishes being distributed on the bare soil declined only slowly from 1 to 20 m distance from the area drilled. Seed batches with more abrasion and higher content of active substances in the dust resulted in higher residues off crop. After drilling of maize in four experiments in Petri dishes in adjacent non crop areas in 1-5 m distance between 0.02 and 0.40 g a.s./ha of neonicotinoids and in the adjacent oil seed rape a total of 0.05–0.80 g a.s./ha were detected. After drilling oil seed rape or barley these values were only 0.02–0.06 g a.s./ha in Petri dishes in non crop areas and 0.03-0.08 g a.s./ha in total in adjacent white mustard. In gauze net samplers installed vertically in 3 m distance in non crop areas up to seven times higher values were detected compared to Petri dishes.

  10. Segmentation of the Infant Food Market

    OpenAIRE

    Hrůzová, Daniela

    2015-01-01

    The theoretical part covers general market segmentation, namely the marketing importance of differences among consumers, the essence of market segmentation, its main conditions and the process of segmentation, which consists of four consecutive phases - defining the market, determining important criteria, uncovering segments and developing segment profiles. The segmentation criteria, segmentation approaches, methods and techniques for the process of market segmentation are also described in t...

  11. Modeling fires in adjacent ship compartments with computational fluid dynamics

    International Nuclear Information System (INIS)

    Wix, S.D.; Cole, J.K.; Koski, J.A.

    1998-01-01

    This paper presents an analysis of the thermal effects on radioactive (RAM) transportation pack ages with a fire in an adjacent compartment. An assumption for this analysis is that the adjacent hold fire is some sort of engine room fire. Computational fluid dynamics (CFD) analysis tools were used to perform the analysis in order to include convective heat transfer effects. The analysis results were compared to experimental data gathered in a series of tests on the United States Coast Guard ship Mayo Lykes located at Mobile, Alabama. (authors)

  12. Nonlinear spin wave coupling in adjacent magnonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Sadovnikov, A. V., E-mail: sadovnikovav@gmail.com; Nikitov, S. A. [Laboratory “Metamaterials,” Saratov State University, Saratov 410012 (Russian Federation); Kotel' nikov Institute of Radioengineering and Electronics, Russian Academy of Sciences, Moscow 125009 (Russian Federation); Beginin, E. N.; Morozova, M. A.; Sharaevskii, Yu. P.; Grishin, S. V.; Sheshukova, S. E. [Laboratory “Metamaterials,” Saratov State University, Saratov 410012 (Russian Federation)

    2016-07-25

    We have experimentally studied the coupling of spin waves in the adjacent magnonic crystals. Space- and time-resolved Brillouin light-scattering spectroscopy is used to demonstrate the frequency and intensity dependent spin-wave energy exchange between the side-coupled magnonic crystals. The experiments and the numerical simulation of spin wave propagation in the coupled periodic structures show that the nonlinear phase shift of spin wave in the adjacent magnonic crystals leads to the nonlinear switching regime at the frequencies near the forbidden magnonic gap. The proposed side-coupled magnonic crystals represent a significant advance towards the all-magnonic signal processing in the integrated magnonic circuits.

  13. Nonlinear spin wave coupling in adjacent magnonic crystals

    International Nuclear Information System (INIS)

    Sadovnikov, A. V.; Nikitov, S. A.; Beginin, E. N.; Morozova, M. A.; Sharaevskii, Yu. P.; Grishin, S. V.; Sheshukova, S. E.

    2016-01-01

    We have experimentally studied the coupling of spin waves in the adjacent magnonic crystals. Space- and time-resolved Brillouin light-scattering spectroscopy is used to demonstrate the frequency and intensity dependent spin-wave energy exchange between the side-coupled magnonic crystals. The experiments and the numerical simulation of spin wave propagation in the coupled periodic structures show that the nonlinear phase shift of spin wave in the adjacent magnonic crystals leads to the nonlinear switching regime at the frequencies near the forbidden magnonic gap. The proposed side-coupled magnonic crystals represent a significant advance towards the all-magnonic signal processing in the integrated magnonic circuits.

  14. Transplantation of retinal pigment epithelial cells - a possible future treatment for age-related macular degeneration

    DEFF Research Database (Denmark)

    Wiencke, Anne Katrine

    2001-01-01

    ophthalmology, age-related macular degeneration, transplantation, retinal pigment epithelial cells, treatment......ophthalmology, age-related macular degeneration, transplantation, retinal pigment epithelial cells, treatment...

  15. Transplantation of retinal pigment epithelial cells - a possible future treatment for age-related macular degeneration

    DEFF Research Database (Denmark)

    Wiencke, Anne Katrine

    2001-01-01

    ophthalmology, age-related macular degeneration, retinal pigment epithelial cells, transplantation, treatment......ophthalmology, age-related macular degeneration, retinal pigment epithelial cells, transplantation, treatment...

  16. Phasing multi-segment undulators

    International Nuclear Information System (INIS)

    Chavanne, J.; Elleaume, P.; Vaerenbergh, P. Van

    1996-01-01

    An important issue in the manufacture of multi-segment undulators as a source of synchrotron radiation or as a free-electron laser (FEL) is the phasing between successive segments. The state of the art is briefly reviewed, after which a novel pure permanent magnet phasing section that is passive and does not require any current is presented. The phasing section allows the introduction of a 6 mm longitudinal gap between each segment, resulting in complete mechanical independence and reduced magnetic interaction between segments. The tolerance of the longitudinal positioning of one segment with respect to the next is found to be 2.8 times lower than that of conventional phasing. The spectrum at all gaps and useful harmonics is almost unchanged when compared with a single-segment undulator of the same total length. (au) 3 refs

  17. Type II Modic Changes May not Always Represent Fat Degeneration: A Study Using MR Fat Suppression Sequence.

    Science.gov (United States)

    Feng, Zhiyun; Liu, Yuanhao; Wei, Wei; Hu, Shengping; Wang, Yue

    2016-08-15

    A radiological study of type II Modic changes (MCs). The aim of this study was to determine the characteristics of type II MCs on fat suppression (FS) magnetic resonance (MR) images and its association with radiological disc degeneration. Type II MCs are common endplate signal changes on MR images. On the basis of limited histological samples, type II MCs are thought to be stable fat degeneration. FS technique on MR, which can quantify fat content, may be an alternative to explore the pathology of MCs. To date, however, the characteristics of type II MCs on FS sequence have not been studied. Lumbar MR images conducted in a single hospital during a defined period were reviewed to include those with type II MCs and FS images. On FS images, signal status of type II MCs was visually classified as suppressed or not-suppressed. Signal intensity of vertebral regions with and without MCs was measured quantitatively on T2-weighted (T2W) and FS images to calculate fat content index and validate the visual classification. Using image analysis program Osirix, MCs size and adjacent disc degeneration were measured quantitatively. Paired t-tests and logistic regressions were used to determine the associations studied. Sixty-four lumbar MRIs were included and 150 endplates with type II MCs were studied. Although signal of 37 (24.7%) type II MCs was suppressed on FS images, that of 113 (75.3%) was not suppressed. The discs adjacent to type II MCs had lower signal intensity (0.13 ± 0.003 vs. 0.14 ± 0.004, P Type II MCs that were not suppressed on FS image were associated with greater age [odds ratio (OR) = 1.11, P type II MCs was not suppressed on FS MR images, suggesting that there are ongoing complicated pathologies. Type II MCs may not merely represent fat replacement. 3.

  18. The LOFT Ground Segment

    DEFF Research Database (Denmark)

    Bozzo, E.; Antonelli, A.; Argan, A.

    2014-01-01

    targets per orbit (~90 minutes), providing roughly ~80 GB of proprietary data per day (the proprietary period will be 12 months). The WFM continuously monitors about 1/3 of the sky at a time and provides data for about ~100 sources a day, resulting in a total of ~20 GB of additional telemetry. The LOFT...... Burst alert System additionally identifies on-board bright impulsive events (e.g., Gamma-ray Bursts, GRBs) and broadcasts the corresponding position and trigger time to the ground using a dedicated system of ~15 VHF receivers. All WFM data are planned to be made public immediately. In this contribution...... we summarize the planned organization of the LOFT ground segment (GS), as established in the mission Yellow Book 1 . We describe the expected GS contributions from ESA and the LOFT consortium. A review is provided of the planned LOFT data products and the details of the data flow, archiving...

  19. Segmented heat exchanger

    Science.gov (United States)

    Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann

    2010-12-14

    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  20. International EUREKA: Market Segment

    International Nuclear Information System (INIS)

    1982-03-01

    The purpose of the Market Segment of the EUREKA model is to simultaneously project uranium market prices, uranium supply and purchasing activities. The regional demands are extrinsic. However, annual forward contracting activities to meet these demands as well as inventory requirements are calculated. The annual price forecast is based on relatively short term, forward balances between available supply and desired purchases. The forecasted prices and extrapolated price trends determine decisions related to exploration and development, new production operations, and the operation of existing capacity. Purchasing and inventory requirements are also adjusted based on anticipated prices. The calculation proceeds one year at a time. Conditions calculated at the end of one year become the starting conditions for the calculation in the subsequent year

  1. Probabilistic retinal vessel segmentation

    Science.gov (United States)

    Wu, Chang-Hua; Agam, Gady

    2007-03-01

    Optic fundus assessment is widely used for diagnosing vascular and non-vascular pathology. Inspection of the retinal vasculature may reveal hypertension, diabetes, arteriosclerosis, cardiovascular disease and stroke. Due to various imaging conditions retinal images may be degraded. Consequently, the enhancement of such images and vessels in them is an important task with direct clinical applications. We propose a novel technique for vessel enhancement in retinal images that is capable of enhancing vessel junctions in addition to linear vessel segments. This is an extension of vessel filters we have previously developed for vessel enhancement in thoracic CT scans. The proposed approach is based on probabilistic models which can discern vessels and junctions. Evaluation shows the proposed filter is better than several known techniques and is comparable to the state of the art when evaluated on a standard dataset. A ridge-based vessel tracking process is applied on the enhanced image to demonstrate the effectiveness of the enhancement filter.

  2. Herpetology of the American Madrean Archipelago and adjacent valleys

    Science.gov (United States)

    Lawrence L. C. Jones

    2005-01-01

    Approximately 110 species of amphibians (18 frogs and toads, and 1 salamander) and reptiles (47 snakes, 39 lizards, and 5 turtles) are known from the American Madrean Archipelago and adjacent valleys. The high diversity of the herpetofauna comes from a variety of factors, including a convergence of biotic communities representing deserts, grasslands, and mountains....

  3. Developmental tumors and adjacent cortical dysplasia: single or dual pathology?

    Science.gov (United States)

    Palmini, André; Paglioli, Eliseu; Silva, Vinicius Duval

    2013-12-01

    Developmental tumors often lead to refractory partial seizures and constitute a well-defined, surgically remediable epilepsy syndrome. Dysplastic features are often associated with these tumors, and their significance carries both practical and conceptual relevance. If associated focal cortical dysplasia (FCD) relates to the extent of the epileptogenic tissue, then presurgical evaluation and surgical strategies should target both the tumor and the surrounding dyslaminated cortex. Furthermore, the association has been included in the recently revised classification of FCD and the epileptogenicity of this associated dysplastic tissue is crucial to validate such revision. In addition to the possibility of representing dual pathology, the association of developmental tumors and adjacent dysplasia may instead represent a single developmental lesion with distinct parts distributed along a histopathologic continuum. Moreover, the possibility that this adjacent dyslamination is of minor epileptogenic relevance should also be entertained. Surgical data show that complete resection of the solid tumors and immediately adjacent tissue harboring satellites may disrupt epileptogenic networks and lead to high rates of seizure freedom, challenging the epileptogenic relevance of more extensive adjacent dyslaminated cortex. Whether the latter is a primary or secondary abnormality and whether dyslaminated cortex in the context of a second lesion may produce seizures after complete resection of the main lesion is still to be proven. Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.

  4. The dynamics of microtidal lagoons and adjacent coasts

    NARCIS (Netherlands)

    Stive, M.J.F.; Capobianco, M.; Wang, Z.B.; Ruol, P.

    1996-01-01

    We have formulated an aggregated-scale behaviour-model for the interaction between a tidal basin and its adjacent coastal environment, without adopting a priory assumptions about their independent dynamic equilibrium behaviour. Necessarily so, the model combines observations and findings resuhing

  5. Do Mangroves Subsidize Carbon to Adjacent Mudflat Fish Communities?

    Science.gov (United States)

    Henkel, S.; Kasten, S.; Hartmann, J.; Staubwasser, M.; Hernandez, M. F.; West, L.; Midway, S. R.; Polito, M. J.

    2017-12-01

    Mangroves are often implicated as energetic sources for fisheries productivity. However, the validity of this connection still remains in contention. Stable isotopes may provide answers by tracking the use of specific basal carbon sources in fish and invertebrates living in mangrove-mudflat habitat mosaics. We analyzed 307 consumer samples representing n=44 fish and invertebrate species collected from mangrove forest creeks and adjacent mudflats in coastal Tanzania using bulk carbon and nitrogen stable isotope analysis. Given the proposed high productivity of mangrove habitats, we hypothesize that mudflat communities will have carbon stable isotope values similar to mangrove communities either through the flux of mangrove carbon into adjacent mudflats and/or via the movement of mudflat fish communities into and out of mangrove habitats. Alternatively, mangrove carbon is often refractory, which may result in mudflat communities with isotopic values that differ from those found in adjacent mangrove communities. This scenario would suggest limited carbon flow between mudflat and mangrove food webs and that the movement of fish into and out of mangrove habitats is related to shelter from predation more than feeding. Data analysis is ongoing to test these competing hypotheses. By understanding the contribution of mangrove carbon to adjacent habitats, managers in Tanzania can make better informed decisions regarding the protection of mangroves and the local fisheries, which are a crucial source of income and food.

  6. Measurement Methods to Determine Air Leakage Between Adjacent Zones

    Energy Technology Data Exchange (ETDEWEB)

    Hult, Erin L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dickerhoff, Darryl J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Phillip N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-09-01

    Air leakage between adjacent zones of a building can lead to indoor air quality and energy efficiency concerns, however there is no existing standard for measuring inter-zonal leakage. In this study, synthesized data and field measurements are analyzed in order to explore the uncertainty associated with different methods for collecting and analyzing fan pressurization measurements to calculate interzone leakage.

  7. Optimal induced universal graphs and adjacency labeling for trees

    DEFF Research Database (Denmark)

    Alstrup, Stephen; Dahlgaard, Søren; Knudsen, Mathias Bæk Tejs

    2015-01-01

    bound. The lower bound and previously best upper bounds were presented in Alstrup and Rauhe (FOCS'02). Our upper bounds are obtained through a log2 n + O(1) labeling scheme for adjacency queries in forests. We hereby solve an open problem being raised repeatedly over decades, e.g. in Kannan, Naor...

  8. Progress toward the maintenance and repair of degenerating retinal circuitry.

    Science.gov (United States)

    Vugler, Anthony A

    2010-01-01

    Retinal diseases such as age-related macular degeneration and retinitis pigmentosa remain major causes of severe vision loss in humans. Clinical trials for treatment of retinal degenerations are underway and advancements in our understanding of retinal biology in health/disease have implications for novel therapies. A review of retinal biology is used to inform a discussion of current strategies to maintain/repair neural circuitry in age-related macular degeneration, retinitis pigmentosa, and Type 2 Leber congenital amaurosis. In age-related macular degeneration/retinitis pigmentosa, a progressive loss of rods/cones results in corruption of bipolar cell circuitry, although retinal output neurons/photoreceptive melanopsin cells survive. Visual function can be stabilized/enhanced after treatment in age-related macular degeneration, but in advanced degenerations, reorganization of retinal circuitry may preclude attempts to restore cone function. In Type 2 Leber congenital amaurosis, useful vision can be restored by gene therapy where central cones survive. Remarkable progress has been made in restoring vision to rodents using light-responsive ion channels inserted into bipolar cells/retinal ganglion cells. Advances in genetic, cellular, and prosthetic therapies show varying degrees of promise for treating retinal degenerations. While functional benefits can be obtained after early therapeutic interventions, efforts should be made to minimize circuitry changes as soon as possible after rod/cone loss. Advances in retinal anatomy/physiology and genetic technologies should allow refinement of future reparative strategies.

  9. Reproducibility of myelin content-based human habenula segmentation at 3 Tesla.

    Science.gov (United States)

    Kim, Joo-Won; Naidich, Thomas P; Joseph, Joshmi; Nair, Divya; Glasser, Matthew F; O'halloran, Rafael; Doucet, Gaelle E; Lee, Won Hee; Krinsky, Hannah; Paulino, Alejandro; Glahn, David C; Anticevic, Alan; Frangou, Sophia; Xu, Junqian

    2018-03-26

    In vivo morphological study of the human habenula, a pair of small epithalamic nuclei adjacent to the dorsomedial thalamus, has recently gained significant interest for its role in reward and aversion processing. However, segmenting the habenula from in vivo magnetic resonance imaging (MRI) is challenging due to the habenula's small size and low anatomical contrast. Although manual and semi-automated habenula segmentation methods have been reported, the test-retest reproducibility of the segmented habenula volume and the consistency of the boundaries of habenula segmentation have not been investigated. In this study, we evaluated the intra- and inter-site reproducibility of in vivo human habenula segmentation from 3T MRI (0.7-0.8 mm isotropic resolution) using our previously proposed semi-automated myelin contrast-based method and its fully-automated version, as well as a previously published manual geometry-based method. The habenula segmentation using our semi-automated method showed consistent boundary definition (high Dice coefficient, low mean distance, and moderate Hausdorff distance) and reproducible volume measurement (low coefficient of variation). Furthermore, the habenula boundary in our semi-automated segmentation from 3T MRI agreed well with that in the manual segmentation from 7T MRI (0.5 mm isotropic resolution) of the same subjects. Overall, our proposed semi-automated habenula segmentation showed reliable and reproducible habenula localization, while its fully-automated version offers an efficient way for large sample analysis. © 2018 Wiley Periodicals, Inc.

  10. Age related macular degeneration and visual disability.

    Science.gov (United States)

    Christoforidis, John B; Tecce, Nicola; Dell'Omo, Roberto; Mastropasqua, Rodolfo; Verolino, Marco; Costagliola, Ciro

    2011-02-01

    Age-related macular degeneration (AMD) is the leading cause of central blindness or low vision among the elderly in industrialized countries. AMD is caused by a combination of genetic and environmental factors. Among modifiable environmental risk factors, cigarette smoking has been associated with both the dry and wet forms of AMD and may increase the likelihood of worsening pre-existing AMD. Despite advances, the treatment of AMD has limitations and affected patients are often referred for low vision rehabilitation to help them cope with their remaining eyesight. The characteristic visual impairment for both forms of AMD is loss of central vision (central scotoma). This loss results in severe difficulties with reading that may be only partly compensated by magnifying glasses or screen-projection devices. The loss of central vision associated with the disease has a profound impact on patient quality of life. With progressive central visual loss, patients lose their ability to perform the more complex activities of daily living. Common vision aids include low vision filters, magnifiers, telescopes and electronic aids. Low vision rehabilitation (LVR) is a new subspecialty emerging from the traditional fields of ophthalmology, optometry, occupational therapy, and sociology, with an ever-increasing impact on the usual concepts of research, education, and services for visually impaired patients. Relatively few ophthalmologists practise LVR and fewer still routinely use prismatic image relocation (IR) in AMD patients. IR is a method of stabilizing oculomotor functions with the purpose of promoting better function of preferred retinal loci (PRLs). The aim of vision rehabilitation therapy consists in the achievement of techniques designed to improve PRL usage. The use of PRLs to compensate for diseased foveae has offered hope to these patients in regaining some function. However, in a recently published meta-analysis, prism spectacles were found to be unlikely to be of

  11. Segmentation-DrivenTomographic Reconstruction

    DEFF Research Database (Denmark)

    Kongskov, Rasmus Dalgas

    such that the segmentation subsequently can be carried out by use of a simple segmentation method, for instance just a thresholding method. We tested the advantages of going from a two-stage reconstruction method to a one stage segmentation-driven reconstruction method for the phase contrast tomography reconstruction......The tomographic reconstruction problem is concerned with creating a model of the interior of an object from some measured data, typically projections of the object. After reconstructing an object it is often desired to segment it, either automatically or manually. For computed tomography (CT...

  12. Automated medical image segmentation techniques

    Directory of Open Access Journals (Sweden)

    Sharma Neeraj

    2010-01-01

    Full Text Available Accurate segmentation of medical images is a key step in contouring during radiotherapy planning. Computed topography (CT and Magnetic resonance (MR imaging are the most widely used radiographic techniques in diagnosis, clinical studies and treatment planning. This review provides details of automated segmentation methods, specifically discussed in the context of CT and MR images. The motive is to discuss the problems encountered in segmentation of CT and MR images, and the relative merits and limitations of methods currently available for segmentation of medical images.

  13. ADVANCED CLUSTER BASED IMAGE SEGMENTATION

    Directory of Open Access Journals (Sweden)

    D. Kesavaraja

    2011-11-01

    Full Text Available This paper presents efficient and portable implementations of a useful image segmentation technique which makes use of the faster and a variant of the conventional connected components algorithm which we call parallel Components. In the Modern world majority of the doctors are need image segmentation as the service for various purposes and also they expect this system is run faster and secure. Usually Image segmentation Algorithms are not working faster. In spite of several ongoing researches in Conventional Segmentation and its Algorithms might not be able to run faster. So we propose a cluster computing environment for parallel image Segmentation to provide faster result. This paper is the real time implementation of Distributed Image Segmentation in Clustering of Nodes. We demonstrate the effectiveness and feasibility of our method on a set of Medical CT Scan Images. Our general framework is a single address space, distributed memory programming model. We use efficient techniques for distributing and coalescing data as well as efficient combinations of task and data parallelism. The image segmentation algorithm makes use of an efficient cluster process which uses a novel approach for parallel merging. Our experimental results are consistent with the theoretical analysis and practical results. It provides the faster execution time for segmentation, when compared with Conventional method. Our test data is different CT scan images from the Medical database. More efficient implementations of Image Segmentation will likely result in even faster execution times.

  14. Involvement of Endoplasmic Reticulum Stress in TULP1 Induced Retinal Degeneration.

    Directory of Open Access Journals (Sweden)

    Glenn P Lobo

    Full Text Available Inherited retinal disorders (IRDs result in severe visual impairments in children and adults. A challenge in the field of retinal degenerations is identifying mechanisms of photoreceptor cell death related to specific genetic mutations. Mutations in the gene TULP1 have been associated with two forms of IRDs, early-onset retinitis pigmentosa (RP and Leber congenital amaurosis (LCA. TULP1 is a cytoplasmic, membrane-associated protein shown to be involved in transportation of newly synthesized proteins destined for the outer segment compartment of photoreceptor cells; however, how mutant TULP1 causes cell death is not understood. In this study, we provide evidence that common missense mutations in TULP1 express as misfolded protein products that accumulate within the endoplasmic reticulum (ER causing prolonged ER stress. In an effort to maintain protein homeostasis, photoreceptor cells then activate the unfolded protein response (UPR complex. Our results indicate that the two major apoptotic arms of the UPR pathway, PERK and IRE1, are activated. Additionally, we show that retinas expressing mutant TULP1 significantly upregulate the expression of CHOP, a UPR signaling protein promoting apoptosis, and undergo photoreceptor cell death. Our study demonstrates that the ER-UPR, a known mechanism of apoptosis secondary to an overwhelming accumulation of misfolded protein, is involved in photoreceptor degeneration caused by missense mutations in TULP1. These observations suggest that modulating the UPR pathways might be a strategy for therapeutic intervention.

  15. Retinal Structure Measurements as Inclusion Criteria for Stem Cell-Based Therapies of Retinal Degenerations.

    Science.gov (United States)

    Jacobson, Samuel G; Matsui, Rodrigo; Sumaroka, Alexander; Cideciyan, Artur V

    2016-04-01

    We reviewed and illustrated the most optimal retinal structural measurements to make in stem cell clinical trials. Optical coherence tomography (OCT) and autofluorescence (AF) imaging were used to evaluate patients with severe visual loss from nonsyndromic and syndromic retinitis pigmentosa (RP), ABCA4-Stargardt disease, and nonneovascular age-related macular degeneration (AMD). Outer nuclear layer (ONL), rod outer segment (ROS) layer, inner retina, ganglion cell layer (GCL), and nerve fiber layer (NFL) thicknesses were quantified. All patients had severely reduced visual acuities. Retinitis pigmentosa patients had limited visual fields; maculopathy patients had central scotomas with retained peripheral function. For the forms of RP illustrated, there was detectable albeit severely reduced ONL across the scanned retina, and normal or hyperthick GCL and NFL. Maculopathy patients had no measurable ONL centrally; it became detectable with eccentricity. Some maculopathy patients showed unexpected GCL losses. Autofluorescence imaging illustrated central losses of RPE integrity. A hypothetical scheme to relate patient data with different phases of retinal remodeling in animal models of retinal degeneration was presented. Stem cell science is advancing, but it is not too early to open the discussion of criteria for patient selection and monitoring. Available clinical tools, such as OCT and AF imaging, can provide inclusion/exclusion criteria and robust objective outcomes. Accepting that early trials may not lead to miraculous cures, we should be prepared to know why-scientifically and clinically-so we can improve subsequent trials. We also must determine if retinal remodeling is an impediment to efficacy.

  16. Fine Mapping of a Degenerated Abdominal Legs Mutant (Edl in Silkworm, Bombyx mori.

    Directory of Open Access Journals (Sweden)

    Honglei Wang

    Full Text Available In insects, abdominal appendages, also called prolegs, vary due to adaptive evolution. Mutations on prolegs within species provide insights to better understand the mechanisms underlying appendage development and diversity. In silkworm Bombyx mori, extra-crescents and degenerated abdominal legs (Edl mutant, belonging to the E pseudoallele group, is a spontaneous mutation that adds crescents and degenerates prolegs on the third abdominal segment (A3. This mutation may be a homeotic transformation of A3 to A2. In this study, the Edl locus was mapped within approximately a 211 Kb region that is 10 Kb upstream of Bmabdominal-A (Bmabd-A. RT-quantitative PCR (RT-qPCR and Western blot analysis of Bmabd-A expression showed a slight but significant decrease, while the expression of BmUltrabithorax (BmUbx was up-regulated in the Edl mutant compared to wildtype (Dazao. Moreover, we also found that BmDistal-less (BmDll, which regulated the development of distal proleg structures, was missing at the tips of the A3 prolegs in the Edl mutant compared to BmDll expression in normally developed prolegs in both the wildtype and mutant. Collectively, we identified approximately a 211 Kb region in the Edl locus that regulates BmUbx and Bmabd-A expression and found that changes in BmUbx and Bmabd-A expression may lead to the loss of distal proleg structures in B. mori.

  17. Transpressional deformation style and AMS fabrics adjacent to the southernmost segment of the San Andreas fault, Durmid Hill, CA

    Science.gov (United States)

    French, M.; Wojtal, S. F.; Housen, B.

    2006-12-01

    In the Salton Trough, the trace of the San Andreas Fault (SAF) ends where it intersects the NNW-trending Brawley seismic zone at Durmid Hill (DH). The topographic relief of DH is a product of faulting and folding of Pleistocene Borrego Formation strata (Babcock, 1974). Burgmann's (1991) detailed mapping and analysis of the western part of DH showed that the folds and faults accommodate transpression. Key to Burgmann's work was the recognition that the ~2m thick Bishop Ash, a prominent marker horizon, has been elongated parallel to the hinges of folds and boudinaged. We are mapping in detail the eastern portion of DH, nearer to the trace of the SAF. Folds in the eastern part of DH are tighter and thrust faulting is more prominent, consistent with greater shortening magnitude oblique to the SAF. Boudinage of the ash layer again indicates elongation parallel to fold hinges and subparallel to the SAF. The Bishop Ash locally is limbs in eastern DH, suggesting that significant continuous deformation accompanied the development of map-scale features. We measured anisotropy of magnetic susceptibility (AMS) fabrics in the Bishop Ash in order to assess continuous deformation in the Ash at DH. Because the Bishop Ash at DH is altered, consisting mainly of silica glass and clay minerals, samples from DH have significantly lower magnetic susceptibilities than Bishop Ash samples from elsewhere in the Salton Trough. With such low susceptibilities, there is significant scatter in the orientation of magnetic foliation and lineation in our samples. Still, in some Bishop samples within 1 km of the SAF, magnetic foliation is consistent with fold-related flattening. Magnetic lineation in these samples is consistently sub-parallel to fold hinges, parallel to the elongation direction inferred from boudinage. Even close to the trace of the SAF, this correlation breaks down in map-scale zones where fold hinge lines change attitude, fold shapes change, and the distribution and orientations of fractures and veins changes. These zones of structural complication separate broader regions of more uniform deformation patterns. Together, the geometry of structures and AMS fabrics suggest that deformation in eastern DH occurs by the distortion and reorientation of more or less coherent blocks separated by narrow zones where structural elements change orientation.

  18. A robust approach towards unknown transformation, regional adjacency graphs, multigraph matching, segmentation video frames from unnamed aerial vehicles (UAV)

    Science.gov (United States)

    Gohatre, Umakant Bhaskar; Patil, Venkat P.

    2018-04-01

    In computer vision application, the multiple object detection and tracking, in real-time operation is one of the important research field, that have gained a lot of attentions, in last few years for finding non stationary entities in the field of image sequence. The detection of object is advance towards following the moving object in video and then representation of object is step to track. The multiple object recognition proof is one of the testing assignment from detection multiple objects from video sequence. The picture enrollment has been for quite some time utilized as a reason for the location the detection of moving multiple objects. The technique of registration to discover correspondence between back to back casing sets in view of picture appearance under inflexible and relative change. The picture enrollment is not appropriate to deal with event occasion that can be result in potential missed objects. In this paper, for address such problems, designs propose novel approach. The divided video outlines utilizing area adjancy diagram of visual appearance and geometric properties. Then it performed between graph sequences by using multi graph matching, then getting matching region labeling by a proposed graph coloring algorithms which assign foreground label to respective region. The plan design is robust to unknown transformation with significant improvement in overall existing work which is related to moving multiple objects detection in real time parameters.

  19. Early developed ASD (adjacent segmental disease) in patients after surgical treatment of the spine due to cancer metastases.

    Science.gov (United States)

    Guzik, Grzegorz

    2017-05-12

    The causes of ASD are still relatively unknown. Correlation between clinical status of patients and radiological MRI findings is of primary importance. The radiological classifications proposed by Pfirmann and Oner are most commonly used to assess intradiscal degenerative changes. The aim of the study was to assess the influence of the extension of spine fixation on the risk of developing ASD in a short time after surgery. A total of 332 patients with spinal tumors were treated in our hospital between 2010 and 2013. Of these patients, 287 underwent surgeries. A follow-up MRI examination was performed 12 months after surgical treatment. The study population comprised of 194 patients. Among metastases, breast cancer was predominant (29%); neurological deficits were detected in 76 patients. Metastases were seen in the thoracic (45%) and lumbar (30%) spine; in 25% of cases, they were of multisegmental character. Pathological fractures concerned 88% of the patients. Statistical calculations were made using the χ2 test. Statistical analysis was done using the Statistica v. 10 software. A p value ASD were noted in only seven patients. Two patients had symptoms of nerve root irritation in the lumbar spine. Twenty-two patients (11%) were diagnosed with ASD according to the MRI classifications by Oner, Rijt, and Ramos, while the more sensitive Pfirmann classification allowed to detect the disease in 46 patients (24%). Healthy or almost healthy discs of Oner type I correlated with the criteria of Pfirmann types II and III. The percentage of the incidence of ASD diagnosed 1 year after the surgery using the Pfirmann classifications was significantly higher than diagnosed according to the clinical examination. The incidence of ASD in patients after spine surgeries due to cancer metastases does not differ between the study groups. ASD detectability based on clinical signs is significantly lower than ASD detectability based on MR images according to the system by Pfirrmann et.al. ASD risk increase among patients with multilevel fixation.

  20. Localized thermonuclear runaways and volcanoes on degenerate dwarf stars

    Energy Technology Data Exchange (ETDEWEB)

    Shara, M.M.

    1982-10-15

    Practically all studies to date of thermonuclear runaways on degenerate dwarf stars in binary systems have considered only spherically symmetric eruptions. We emphasize that even slightly non-spherically symmetric accretion leads to transverse temperature gradients in the dwarfs' accreted envelopes. Over a rather broad range of parameter space, thermalization time scales in accreted envelopes are much longer than thermonuclear runaway time scales. Thus localized thermonuclear runaways (i.e., runaways much smaller than the host degenerate star) rather than spherically symmetric global eruptions are likely to occur on many degenerate dwarfs. Localized runaways are more likely to occur on more massive and/or hotter dwarfs.

  1. Acquired Nonpigmented Vitreous Cyst Associated With Lattice Degeneration.

    Science.gov (United States)

    Lu, Jing; Mai, Guiying; Liu, Ruyuan; Luo, Yan; Lu, Lin

    2017-10-01

    A 63-year-old male presented with a round-shaped floater and visual obscuration in the right eye. Clinical evaluation showed a nonpigmented vitreous cyst connected to a lattice degeneration by a stalk. Immunostaining of the vitreous cyst obtained from vitrectomy showed its origin of retinal neuroepithelium. The cyst was formed by continuous vitreous traction, which might tear up the disrupted retina at the area of lattice degeneration. This report added the lattice degeneration to the list of causes for the acquired vitreous cyst. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:856-858.]. Copyright 2017, SLACK Incorporated.

  2. [Clinical features and prognosis of retinal lattice degeneration].

    Science.gov (United States)

    Guo, X R

    1990-07-01

    110 cases (110 eyes) of retinal lattice degeneration were clinically observed and followed up for 3-8 years. Most lesions were located in the superotemporal quadrant, band-shaped, and parallel to the ora serrata. 80.9% of the lesions presented various degrees of pigmentation, 67.1% yellowish white spots, and 83.6% white lines. 32.9% of the eyes developed retinal holes. Most lattice degenerations were accompanied by vitreous degeneration and vitreoretinal traction. The disease progressed only slowly, though in a few cases it tended to expand.

  3. [Current concepts in pathogenesis of age-related macular degeneration].

    Science.gov (United States)

    Kubicka-Trząska, Agnieszka; Karska-Basta, Izabella; Romanowska-Dixon, Bożena

    2014-01-01

    Age-related macular degeneration is the leading cause of central blindness in elderly population of the western world. The pathogenesis of this disease, likely multifactorial, is not well known, although a number of theories have been put forward, including oxidative stress, genetic interactions, hemodynamic imbalance, immune and inflammatory processes. The understanding of age-related macular degeneration pathogenesis will give rise to new approaches in prevention and treatment of the early and late stages of both atrophic and neovascular age-related macular degeneration.

  4. Holistic segmentation of the lung in cine MRI.

    Science.gov (United States)

    Kovacs, William; Hsieh, Nathan; Roth, Holger; Nnamdi-Emeratom, Chioma; Bandettini, W Patricia; Arai, Andrew; Mankodi, Ami; Summers, Ronald M; Yao, Jianhua

    2017-10-01

    Duchenne muscular dystrophy (DMD) is a childhood-onset neuromuscular disease that results in the degeneration of muscle, starting in the extremities, before progressing to more vital areas, such as the lungs. Respiratory failure and pneumonia due to respiratory muscle weakness lead to hospitalization and early mortality. However, tracking the disease in this region can be difficult, as current methods are based on breathing tests and are incapable of distinguishing between muscle involvements. Cine MRI scans give insight into respiratory muscle movements, but the images suffer due to low spatial resolution and poor signal-to-noise ratio. Thus, a robust lung segmentation method is required for accurate analysis of the lung and respiratory muscle movement. We deployed a deep learning approach that utilizes sequence-specific prior information to assist the segmentation of lung in cine MRI. More specifically, we adopt a holistically nested network to conduct image-to-image holistic training and prediction. One frame of the cine MRI is used in the training and applied to the remainder of the sequence ([Formula: see text] frames). We applied this method to cine MRIs of the lung in the axial, sagittal, and coronal planes. Characteristic lung motion patterns during the breathing cycle were then derived from the segmentations and used for diagnosis. Our data set consisted of 31 young boys, age [Formula: see text] years, 15 of whom suffered from DMD. The remaining 16 subjects were age-matched healthy volunteers. For validation, slices from inspiratory and expiratory cycles were manually segmented and compared with results obtained from our method. The Dice similarity coefficient for the deep learning-based method was [Formula: see text] for the sagittal view, [Formula: see text] for the axial view, and [Formula: see text] for the coronal view. The holistic neural network approach was compared with an approach using Demon's registration and showed superior performance. These

  5. Joint Graph Layouts for Visualizing Collections of Segmented Meshes

    KAUST Repository

    Ren, Jing; Schneider, Jens; Ovsjanikov, Maks; Wonka, Peter

    2017-01-01

    We present a novel and efficient approach for computing joint graph layouts and then use it to visualize collections of segmented meshes. Our joint graph layout algorithm takes as input the adjacency matrices for a set of graphs along with partial, possibly soft, correspondences between nodes of different graphs. We then use a two stage procedure, where in the first step, we extend spectral graph drawing to include a consistency term so that a collection of graphs can be handled jointly. Our second step extends metric multi-dimensional scaling with stress majorization to the joint layout setting, while using the output of the spectral approach as initialization. Further, we discuss a user interface for exploring a collection of graphs. Finally, we show multiple example visualizations of graphs stemming from collections of segmented meshes and we present qualitative and quantitative comparisons with previous work.

  6. Endplates Changes Related to Age and Vertebral Segment

    Directory of Open Access Journals (Sweden)

    Carlos Fernando P. S. Herrero

    2014-01-01

    Full Text Available Endplate separations are defined as the presence of a space between the hyaline cartilage and the cortical bone of the adjacent vertebral body. This study evaluates endplate separations from the vertebral body and intervertebral discs and verifies if endplate separation is related to age and the spinal level. Groups were formed based on age (20–40 and 41–85 years old and the vertebral segment (T7-T8 and L4-L5 segments. Histological analysis included assessment of the length of the vertebral endplates, the number and dimensions of the separations, and orientation of the collagen fibers, in the mid-sagittal slice. Two indexes were created: the separation index (number of separations/vertebral length and separation extension index (sum of all separations/vertebral length. The results of the study demonstrated a direct relationship between the density of separations in the endplate and two variables: age and spinal level.

  7. Joint Graph Layouts for Visualizing Collections of Segmented Meshes

    KAUST Repository

    Ren, Jing

    2017-09-12

    We present a novel and efficient approach for computing joint graph layouts and then use it to visualize collections of segmented meshes. Our joint graph layout algorithm takes as input the adjacency matrices for a set of graphs along with partial, possibly soft, correspondences between nodes of different graphs. We then use a two stage procedure, where in the first step, we extend spectral graph drawing to include a consistency term so that a collection of graphs can be handled jointly. Our second step extends metric multi-dimensional scaling with stress majorization to the joint layout setting, while using the output of the spectral approach as initialization. Further, we discuss a user interface for exploring a collection of graphs. Finally, we show multiple example visualizations of graphs stemming from collections of segmented meshes and we present qualitative and quantitative comparisons with previous work.

  8. Photoreceptor inner segment ellipsoid band integrity on spectral domain optical coherence tomography

    Directory of Open Access Journals (Sweden)

    Saxena S

    2014-12-01

    Full Text Available Sandeep Saxena,1 Khushboo Srivastav,1 Chui M Cheung,2 Joanne YW Ng,3 Timothy YY Lai3 1Retina Service, Department of Ophthalmology, King George’s Medical University Lucknow, India; 2Singapore National Eye Centre, Singapore; 3Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong Abstract: Spectral domain optical coherence tomography cross-sectional imaging of the macula has conventionally been resolved into four bands. However, some doubts were raised regarding authentication of the existence of these bands. Recently, a number of studies have suggested that the second band appeared to originate from the inner segment ellipsoids of the foveal cone photoreceptors, and therefore the previously called inner segment-outer segment junction is now referred to as inner segment ellipsoidband. Photoreceptor dysfunction may be a significant predictor of visual acuity in a spectrum of surgical and medical retinal diseases. This review aims to provide an overview and summarizes the role of the photoreceptor inner segment ellipsoid band in the management and prognostication of various vitreoretinal diseases. Keywords: spectral domain optical coherence tomography, inner segment-outer segment junction, external limiting membrane, macular hole, diabetic macular edema, age relate macular degeneration

  9. A Gemini snapshot survey for double degenerates

    Science.gov (United States)

    Kilic, Mukremin; Brown, Warren R.; Gianninas, A.; Curd, Brandon; Bell, Keaton J.; Allende Prieto, Carlos

    2017-11-01

    We present the results from a Gemini snapshot radial-velocity survey of 44 low-mass white-dwarf candidates selected from the Sloan Digital Sky Survey (SDSS) spectroscopy. To find sub-hour orbital period binary systems, our time-series spectroscopy had cadences of 2-8 min over a period of 20-30 min. Through follow-up observations at Gemini and the MMT, we identify four double-degenerate binary systems with periods ranging from 53 min to 7 h. The shortest period system, SDSS J123549.88+154319.3, was recently identified as a sub-hour period detached binary by Breedt and collaborators. Here, we refine the orbital and physical parameters of this system. High-speed and time-domain survey photometry observations do not reveal eclipses or other photometric effects in any of our targets. We compare the period distribution of these four systems with the orbital period distribution of known double white dwarfs; the median period decreases from 0.64 to 0.24 d for M = 0.3-0.5 M⊙ to M < 0.3 M⊙ white dwarfs. However, we do not find a statistically significant correlation between the orbital period and white-dwarf mass.

  10. Correlations in a partially degenerate electron plasma

    Energy Technology Data Exchange (ETDEWEB)

    Chihara, Junzo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    The density-functional theory proves that an ion-electron mixture can be treated as a one-component liquid interacting only via a pairwise interaction in the evaluation of the ion-ion radial distribution function (RDF), and provides a set of integral equations: one is an integral equation for the ion-ion RDF and another for an effective ion-ion interaction, which depends on the ion-ion RDF. This formulation gives a set of integral equation to calculate plasma structures with combined use of the electron-electron correlations in a partially degenerate electron plasma. Therefore, it is important for this purpose to determine the electron-electron correlations at a arbitrary temperature. Here, they are calculated by the quantal version of the hypernetted chain (HNC) equation. On the basis of the jellium-vacancy model, the ionic and electronic structures of rubidium are calculated for the range from liquid metal to plasma states by increasing the temperature at the fixed density using the electron-correlation results. (author)

  11. Radiation therapy: age-related macular degeneration.

    Science.gov (United States)

    Mendez, Carlos A Medina; Ehlers, Justis P

    2013-01-01

    Age-related macular degeneration (AMD) is the leading cause of severe irreversible vision loss in patients over the age of 50 years in the developed world. Neovascular AMD (NVAMD) is responsible for 90% of the cases with severe visual loss. In the last decade, the treatment paradigm for NVAMD has been transformed by the advent of anti-vascular endothelial growth factor therapy. Despite the excellent results of anti-vascular endothelial growth factor therapy, frequent injections remain a necessity for most patients. The burden of these frequent visits as well as the cumulative risks of indefinite intravitreal injections demand continued pursuit of more enduring therapy that provides similar functional results. Radiotherapy has been studied for two decades as a potential therapy for NVAMD. Because of its antiangiogenic properties, radiation therapy remains a promising potential adjunctive resource for the treatment of choroidal neovascularization secondary to NVAMD. This review considers the past, present and future of radiation as a treatment or combination treatment of NVAMD. Copyright © 2013 S. Karger AG, Basel.

  12. On degenerate metrics, dark matter and unification

    Science.gov (United States)

    Searight, Trevor P.

    2017-12-01

    A five-dimensional theory of relativity is presented which suggests that gravitation and electromagnetism may be unified using a degenerate metric. There are four fields (in the four-dimensional sense): a tensor field, two vector fields, and a scalar field, and they are unified with a combination of a gauge-like invariance and a reflection symmetry which means that both vector fields are photons. The gauge-like invariance implies that the fifth dimension is not directly observable; it also implies that charge is a constant of motion. The scalar field is analogous to the Brans-Dicke scalar field, and the theory tends towards the Einstein-Maxwell theory in the limit as the coupling constant tends to infinity. As there is some scope for fields to vary in the fifth dimension, it is possible for the photons to have wave behaviour in the fifth dimension. The wave behaviour has two effects: it gives mass to the photons, and it prevents them from interacting directly with normal matter. These massive photons still act as a source of gravity, however, and therefore they are candidates for dark matter.

  13. Animal models of age related macular degeneration

    Science.gov (United States)

    Pennesi, Mark E.; Neuringer, Martha; Courtney, Robert J.

    2013-01-01

    Age related macular degeneration (AMD) is the leading cause of vision loss of those over the age of 65 in the industrialized world. The prevalence and need to develop effective treatments for AMD has lead to the development of multiple animal models. AMD is a complex and heterogeneous disease that involves the interaction of both genetic and environmental factors with the unique anatomy of the human macula. Models in mice, rats, rabbits, pigs and non-human primates have recreated many of the histological features of AMD and provided much insight into the underlying pathological mechanisms of this disease. In spite of the large number of models developed, no one model yet recapitulates all of the features of human AMD. However, these models have helped reveal the roles of chronic oxidative damage, inflammation and immune dysregulation, and lipid metabolism in the development of AMD. Models for induced choroidal neovascularization have served as the backbone for testing new therapies. This article will review the diversity of animal models that exist for AMD as well as their strengths and limitations. PMID:22705444

  14. Radiotherapy in age-related macula degeneration

    International Nuclear Information System (INIS)

    Gripp, Stephan; Stammen, Johannes; Petersen, Claudia; Hartmann, Axel; Willers, Reinhart; Althaus, Christoph

    2002-01-01

    Purpose: To ascertain the benefit from radiotherapy in age-related macula degeneration in a single-arm longitudinal study. Methods and Materials: From 1997 to 1998, 39 patients with occult and 33 patients with classic choroidal neovascularization (CNV) were irradiated with 16 Gy. Fluorescein angiography and measurements of visual acuity were performed before and 3, 6, and 12 months after irradiation. Results: Complete follow-up data for 1 year were available from 69 patients. The mean patient age was 72 years (range 49-92). Vision decreased in 43, was stable in 18, and improved in 8 cases. The mean vision deteriorated significantly (p=0.02, Wilcoxon test), particularly within the first 3 months. Patients with occult CNV did significantly better than did those with classic CNV (p=0.03). The proportion of patients retaining vision ≥0.2 fell from 65% to 42% (p <0.01), for classic and occult CNV from 50% to 23%, and for occult CNV from 77% to 56% (p<0.02), respectively. CNV size increased in 30 patients and was stable in 38. Neither age (p=0.17) nor gender (p=0.21, chi-square test) influenced prognosis. Four patients reported transitional complaints. Conclusion: Low-dose fractionated radiotherapy with 16 Gy is well tolerated. However, vision and reading ability were not preserved in most patients

  15. Coulomb Logarithm in Nonideal and Degenerate Plasmas

    Science.gov (United States)

    Filippov, A. V.; Starostin, A. N.; Gryaznov, V. K.

    2018-03-01

    Various methods for determining the Coulomb logarithm in the kinetic theory of transport and various variants of the choice of the plasma screening constant, taking into account and disregarding the contribution of the ion component and the boundary value of the electron wavevector are considered. The correlation of ions is taken into account using the Ornstein-Zernike integral equation in the hypernetted-chain approximation. It is found that the effect of ion correlation in a nondegenerate plasma is weak, while in a degenerate plasma, this effect must be taken into account when screening is determined by the electron component alone. The calculated values of the electrical conductivity of a hydrogen plasma are compared with the values determined experimentally in the megabar pressure range. It is shown that the values of the Coulomb logarithm can indeed be smaller than unity. Special experiments are proposed for a more exact determination of the Coulomb logarithm in a magnetic field for extremely high pressures, for which electron scattering by ions prevails.

  16. Double Degenerates among DA white dwarfs

    International Nuclear Information System (INIS)

    Bragaglia, A.; Greggio, L.; Renzini, A.; D'odorico, S.

    1990-01-01

    The results of a spectroscopic survey of catalog white dwarfs in search of radial velocity variations indicative of a binary motion are reported. In a sample of 54 DA white dwarfs, one Double Degenerate (DD) system with a period of 1.15 days (the shortest period DD system yet discovered) is found. Two other excellent and two good DD candidates, and two white dwarf + red dwarf pairs were also found. If all the candidates should be confirmed, this would indicate a frequency of about 13 percent of interacting binaries in an unbiased sample of evolved stars, with a DD frequency of about 10 percent. These results suggest fairly large values for the common-envelope parameter alpha, implying that a source of energy other than orbital may be required to eject the envelope during common-envelope events. Finally, in combination with previous evidence our result implies that DDs with WD components of the DA variety are unlikely to be the precursors of Type I supernovae, but DDs with non-DA components remain very attractive candidates. 20 refs

  17. Magnonic triply-degenerate nodal points

    Science.gov (United States)

    Owerre, S. A.

    2017-12-01

    We generalize the concept of triply-degenerate nodal points to non-collinear antiferromagnets. Here, we introduce this concept to insulating quantum antiferromagnets on the decorated honeycomb lattice, with spin-1 bosonic quasiparticle excitations known as magnons. We demonstrate the existence of magnonic surface states with constant energy contours that form pairs of magnonic arcs connecting the surface projection of the magnonic triple nodal points. The quasiparticle excitations near the triple nodal points represent three-component bosons beyond that of magnonic Dirac, Weyl, and nodal-line cases. They can be regarded as a direct reflection of the intrinsic spin carried by magnons. Furthermore, we show that the magnonic triple nodal points can split into magnonic Weyl points, as the system transits from a non-collinear spin structure to a non-coplanar one with a non-zero scalar spin chirality. Our results not only apply to insulating antiferromagnets, but also provide a platform to seek for triple nodal points in metallic antiferromagnets.

  18. Cryopreserved embryo transfer: adjacent or non-adjacent to failed fresh long GnRH-agonist protocol IVF cycle.

    Science.gov (United States)

    Volodarsky-Perel, Alexander; Eldar-Geva, Talia; Holzer, Hananel E G; Schonberger, Oshrat; Reichman, Orna; Gal, Michael

    2017-03-01

    The optimal time to perform cryopreserved embryo transfer (CET) after a failed oocyte retrieval-embryo transfer (OR-ET) cycle is unknown. Similar clinical pregnancy rates were recently reported in immediate and delayed CET, performed after failed fresh OR-ET, in cycles with the gonadotrophin-releasing hormone (GnRH) antagonist protocol. This study compared outcomes of CET performed adjacently (<50 days, n = 67) and non-adjacently (≥50 to 120 days, n = 62) to the last OR-day of cycles with the GnRH agonist down-regulation protocol. Additional inclusion criteria were patients' age 20-38 years, the transfer of only 1-2 cryopreserved embryos, one treatment cycle per patient and artificial preparation for CET. Significantly higher implantation, clinical pregnancy and live birth rates were found in the non-adjacent group than in the adjacent group: 30.5% versus 11.3% (P = 0.001), 41.9% versus 17.9% (P = 0.003) and 32.3% versus 13.4% (P = 0.01), respectively. These results support the postponement of CET after a failed OR-ET for at least one menstrual cycle, when a preceding long GnRH-agonist protocol is used. Copyright © 2016 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  19. Retinal Vessels Segmentation Techniques and Algorithms: A Survey

    Directory of Open Access Journals (Sweden)

    Jasem Almotiri

    2018-01-01

    Full Text Available Retinal vessels identification and localization aim to separate the different retinal vasculature structure tissues, either wide or narrow ones, from the fundus image background and other retinal anatomical structures such as optic disc, macula, and abnormal lesions. Retinal vessels identification studies are attracting more and more attention in recent years due to non-invasive fundus imaging and the crucial information contained in vasculature structure which is helpful for the detection and diagnosis of a variety of retinal pathologies included but not limited to: Diabetic Retinopathy (DR, glaucoma, hypertension, and Age-related Macular Degeneration (AMD. With the development of almost two decades, the innovative approaches applying computer-aided techniques for segmenting retinal vessels are becoming more and more crucial and coming closer to routine clinical applications. The purpose of this paper is to provide a comprehensive overview for retinal vessels segmentation techniques. Firstly, a brief introduction to retinal fundus photography and imaging modalities of retinal images is given. Then, the preprocessing operations and the state of the art methods of retinal vessels identification are introduced. Moreover, the evaluation and validation of the results of retinal vessels segmentation are discussed. Finally, an objective assessment is presented and future developments and trends are addressed for retinal vessels identification techniques.

  20. Region segmentation along image sequence

    International Nuclear Information System (INIS)

    Monchal, L.; Aubry, P.

    1995-01-01

    A method to extract regions in sequence of images is proposed. Regions are not matched from one image to the following one. The result of a region segmentation is used as an initialization to segment the following and image to track the region along the sequence. The image sequence is exploited as a spatio-temporal event. (authors). 12 refs., 8 figs

  1. Market segmentation using perceived constraints

    Science.gov (United States)

    Jinhee Jun; Gerard Kyle; Andrew Mowen

    2008-01-01

    We examined the practical utility of segmenting potential visitors to Cleveland Metroparks using their constraint profiles. Our analysis identified three segments based on their scores on the dimensions of constraints: Other priorities--visitors who scored the highest on 'other priorities' dimension; Highly Constrained--visitors who scored relatively high on...

  2. Market Segmentation: An Instructional Module.

    Science.gov (United States)

    Wright, Peter H.

    A concept-based introduction to market segmentation is provided in this instructional module for undergraduate and graduate transportation-related courses. The material can be used in many disciplines including engineering, business, marketing, and technology. The concept of market segmentation is primarily a transportation planning technique by…

  3. IFRS 8 – OPERATING SEGMENTS

    Directory of Open Access Journals (Sweden)

    BOCHIS LEONICA

    2009-05-01

    Full Text Available Segment reporting in accordance with IFRS 8 will be mandatory for annual financial statements covering periods beginning on or after 1 January 2009. The standards replaces IAS 14, Segment Reporting, from that date. The objective of IFRS 8 is to require

  4. Reduplication Facilitates Early Word Segmentation

    Science.gov (United States)

    Ota, Mitsuhiko; Skarabela, Barbora

    2018-01-01

    This study explores the possibility that early word segmentation is aided by infants' tendency to segment words with repeated syllables ("reduplication"). Twenty-four nine-month-olds were familiarized with passages containing one novel reduplicated word and one novel non-reduplicated word. Their central fixation times in response to…

  5. The Importance of Marketing Segmentation

    Science.gov (United States)

    Martin, Gillian

    2011-01-01

    The rationale behind marketing segmentation is to allow businesses to focus on their consumers' behaviors and purchasing patterns. If done effectively, marketing segmentation allows an organization to achieve its highest return on investment (ROI) in turn for its marketing and sales expenses. If an organization markets its products or services to…

  6. Essays in international market segmentation

    NARCIS (Netherlands)

    Hofstede, ter F.

    1999-01-01

    The primary objective of this thesis is to develop and validate new methodologies to improve the effectiveness of international segmentation strategies. The current status of international market segmentation research is reviewed in an introductory chapter, which provided a number of

  7. Mesiodistal tooth angulation to segmental occlusal plane in panoramic radiography

    International Nuclear Information System (INIS)

    Kim, Jae Duk; Kim, Jin Soo; You, Choong Hyun

    2005-01-01

    To evaluate the stability of the segmental occlusal plane and anatomical line as the reference line for measuring the mesiodistal tooth angulation in panoramic radiography and to determine the mean angle and the range of the mesiodistal tooth angulation in Korean population with normal occlusions. Twenty nine subjects (15 men, 14 women) with normal occlusion were selected. A total of 29 panoramic radiograms were taken at normal head position and then 10 images of 5 subjects selected were repeatedly taken with repositioning 2 times at each of the head down (V-shaped occlusion) and up (horizontal occulsion) for evaluation of stability of adopted reference lines by using PM2002CC (Planmeca, Finland). The images were traced with adoption of two test reference lines and the long axes of the teeth. The mesial angles formed by each reference line and the long axes of the teeth were measured and analyzed. With anatomical reference line, the mesiodistal tooth angulations of the molars showed the significant difference by over 5 degree between the normal and each changed head position. With segmented occlusal reference line, deviations of mesiodistal tooth angulations by the two changed head positions were less than 1 degree. The means, standard deviations, and maximum and minimum values of mesiodistal tooth angulations to segmental occlusal reference line on panoramic radiography were determined. It would appear that mesiodistal tooth angulations to segmental occlusal plane as reference line in panograms are predictable as standards of normal occlusion and useful for evaluation of tooth arrangement between adjacent teeth.

  8. Mesiodistal tooth angulation to segmental occlusal plane in panoramic radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Duk; Kim, Jin Soo; You, Choong Hyun [Chosun University College of Medicine, Kwangju (Korea, Republic of)

    2005-03-15

    To evaluate the stability of the segmental occlusal plane and anatomical line as the reference line for measuring the mesiodistal tooth angulation in panoramic radiography and to determine the mean angle and the range of the mesiodistal tooth angulation in Korean population with normal occlusions. Twenty nine subjects (15 men, 14 women) with normal occlusion were selected. A total of 29 panoramic radiograms were taken at normal head position and then 10 images of 5 subjects selected were repeatedly taken with repositioning 2 times at each of the head down (V-shaped occlusion) and up (horizontal occulsion) for evaluation of stability of adopted reference lines by using PM2002CC (Planmeca, Finland). The images were traced with adoption of two test reference lines and the long axes of the teeth. The mesial angles formed by each reference line and the long axes of the teeth were measured and analyzed. With anatomical reference line, the mesiodistal tooth angulations of the molars showed the significant difference by over 5 degree between the normal and each changed head position. With segmented occlusal reference line, deviations of mesiodistal tooth angulations by the two changed head positions were less than 1 degree. The means, standard deviations, and maximum and minimum values of mesiodistal tooth angulations to segmental occlusal reference line on panoramic radiography were determined. It would appear that mesiodistal tooth angulations to segmental occlusal plane as reference line in panograms are predictable as standards of normal occlusion and useful for evaluation of tooth arrangement between adjacent teeth.

  9. Determination of source terms in a degenerate parabolic equation

    International Nuclear Information System (INIS)

    Cannarsa, P; Tort, J; Yamamoto, M

    2010-01-01

    In this paper, we prove Lipschitz stability results for inverse source problems relative to parabolic equations. We use the method introduced by Imanuvilov and Yamamoto in 1998 based on Carleman estimates. What is new here is that we study a class of one-dimensional degenerate parabolic equations. In our model, the diffusion coefficient vanishes at one extreme point of the domain. Instead of the classical Carleman estimates obtained by Fursikov and Imanuvilov for non degenerate equations, we use and extend some recent Carleman estimates for degenerate equations obtained by Cannarsa, Martinez and Vancostenoble. Finally, we obtain Lipschitz stability results in inverse source problems for our class of degenerate parabolic equations both in the case of a boundary observation and in the case of a locally distributed observation

  10. The degenerate-internal-states approximation for cold collisions

    NARCIS (Netherlands)

    Maan, A.C.; Tiesinga, E.; Stoof, H.T.C.; Verhaar, B.J.

    1990-01-01

    The Degenerate-Internal-States approximation as well as its first-order correction are shown to provide a convenient method for calculating elastic and inelastic collision amplitudes for low temperature atomic scattering.

  11. Magnetism and magnetostriction in a degenerate rigid band

    International Nuclear Information System (INIS)

    Kulakowski, K.; Barbara, B.

    1990-09-01

    We investigate the influence of the spin-orbit coupling on the magnetic and magnetoelastic phenomena in ferromagnetic band systems. The description is within the Stoner model of a degenerate rigid band, for temperature T = O. (author). 14 refs

  12. Relativistic degenerate electron plasma in an intense magnetic field

    International Nuclear Information System (INIS)

    Delsante, A.E.; Frankel, N.E.

    1978-01-01

    The dielectric response function for a dense, ultra-degenerate relativistic electron plasma in an intense uniform magnetic field is presented. Dispersion relations for plasma oscillations parallel and perpendicular to the magnetic field are obtained

  13. Arbitrary electron acoustic waves in degenerate dense plasmas

    Science.gov (United States)

    Rahman, Ata-ur; Mushtaq, A.; Qamar, A.; Neelam, S.

    2017-05-01

    A theoretical investigation is carried out of the nonlinear dynamics of electron-acoustic waves in a collisionless and unmagnetized plasma whose constituents are non-degenerate cold electrons, ultra-relativistic degenerate electrons, and stationary ions. A dispersion relation is derived for linear EAWs. An energy integral equation involving the Sagdeev potential is derived, and basic properties of the large amplitude solitary structures are investigated in such a degenerate dense plasma. It is shown that only negative large amplitude EA solitary waves can exist in such a plasma system. The present analysis may be important to understand the collective interactions in degenerate dense plasmas, occurring in dense astrophysical environments as well as in laser-solid density plasma interaction experiments.

  14. An Unusual Case of Extensive Lattice Degeneration and Retinal Detachment.

    Science.gov (United States)

    Mathew, David J; Sarma, Saurabh Kumar; Basaiawmoit, Jennifer V

    2016-07-01

    Lattice degeneration of the retina is not infrequently encountered on a dilated retinal examination and many of them do not need any intervention. We report a case of atypical lattice degeneration variant with peripheral retinal detachment. An asymptomatic 35-year-old lady with minimal refractive error was found to have extensive lattice degeneration, peripheral retinal detachment and fibrotic changes peripherally with elevation of retinal vessels on dilated retinal examination. There were also areas of white without pressure, chorioretinal scarring and retinal breaks. All the changes were limited to beyond the equator but were found to span 360 degrees. She was treated with barrage laser all around to prevent extension of the retinal detachment posteriorly. She remained stable till her latest follow-up two years after the barrage laser. This case is reported for its rarity with a discussion of the probable differential diagnoses. To the best of our knowledge, this is the first report of such findings in lattice degeneration.

  15. An imbedding theorem and its applications in degenerate elliptic equations

    International Nuclear Information System (INIS)

    Duong Minh Duc.

    1988-06-01

    We improve the Rellich-Kondrachov theorem and apply it to study strongly degenerate and singular elliptic equations. We obtain the maximum principle, Harnacks's inequality and global regularity for solutions of those equations. (author). 11 refs

  16. 33 CFR 148.217 - How can a State be designated as an adjacent coastal State?

    Science.gov (United States)

    2010-07-01

    ... an adjacent coastal State? 148.217 Section 148.217 Navigation and Navigable Waters COAST GUARD... General § 148.217 How can a State be designated as an adjacent coastal State? (a) Adjacent coastal States... as an adjacent coastal State in the notice may request to be designated as one if the environmental...

  17. The brain basis of musicophilia: evidence from frontotemporal lobar degeneration

    OpenAIRE

    Phillip David Fletcher; Laura eDowney; Pirada eWitoonpanich; Jason eWarren

    2013-01-01

    Musicophilia, or abnormal craving for music, is a poorly understood phenomenon that has been associated in particular with focal degeneration of the temporal lobes. Here we addressed the brain basis of musicophilia using voxel-based morphometry (VBM) on MR volumetric brain images in a retrospectively ascertained cohort of patients meeting clinical consensus criteria for frontotemporal lobar degeneration: of 37 cases ascertained, 12 had musicophilia and 25 did not exhibit the phenomenon. The s...

  18. Degenerated uterine leiomyomas mimicking malignant bilateral ovarian surface epithelial tumors

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Yi Boem Ha; Lee, Hae Kyung; Lee, Min Hee; Choi, Seo Youn; Chung, Soo Ho [Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon (Korea, Republic of)

    2017-07-15

    Uterine leiomyomas are the most common benign uterine neoplasms. Undegenerated uterine leiomyomas are easily recognizable by the typical imaging findings on radiologic studies. However, degenerated fibroids can have unusual and variable appearances. The atypical appearances due to degenerative changes may cause confusion in diagnosis of leiomyomas. In this article, we report a case of a patient with extensive cystic and myxoid degeneration of uterine leiomyoma, mimicking malignant bilateral ovarian surface epithelial tumors.

  19. Electromagnetic solitons in degenerate relativistic electron–positron plasma

    International Nuclear Information System (INIS)

    Berezhiani, V I; Shatashvili, N L; Tsintsadze, N L

    2015-01-01

    The existence of soliton-like electromagnetic (EM) distributions in a fully degenerate electron–positron plasma is studied applying relativistic hydrodynamic and Maxwell equations. For a circularly polarized wave it is found that the soliton solutions exist both in relativistic as well as nonrelativistic degenerate plasmas. Plasma density in the region of soliton pulse localization is reduced considerably. The possibility of plasma cavitation is also shown. (invited comment)

  20. SINGLE-DEGENERATE TYPE Ia SUPERNOVAE ARE PREFERENTIALLY OVERLUMINOUS

    International Nuclear Information System (INIS)

    Fisher, Robert; Jumper, Kevin

    2015-01-01

    Recent observational and theoretical progress has favored merging and helium-accreting sub-Chandrasekhar mass white dwarfs (WDs) in the double-degenerate and the double-detonation channels, respectively, as the most promising progenitors of normal Type Ia supernovae (SNe Ia). Thus the fate of rapidly accreting Chandrasekhar mass WDs in the single-degenerate channel remains more mysterious then ever. In this paper, we clarify the nature of ignition in Chandrasekhar-mass single-degenerate SNe Ia by analytically deriving the existence of a characteristic length scale which establishes a transition from central ignitions to buoyancy-driven ignitions. Using this criterion, combined with data from three-dimensional simulations of convection and ignition, we demonstrate that the overwhelming majority of ignition events within Chandrasekhar-mass WDs in the single-degenerate channel are buoyancy-driven, and consequently lack a vigorous deflagration phase. We thus infer that single-degenerate SNe Ia are generally expected to lead to overluminous 1991T-like SNe Ia events. We establish that the rates predicted from both the population of supersoft X-ray sources (SSSs) and binary population synthesis models of the single-degenerate channel are broadly consistent with the observed rates of overluminous SNe Ia, and suggest that the population of SSSs are the dominant stellar progenitors of SNe 1991T-like events. We further demonstrate that the single-degenerate channel contribution to the normal and failed 2002cx-like rates is not likely to exceed 1% of the total SNe Ia rate. We conclude with a range of observational tests of overluminous SNe Ia which will either support or strongly constrain the single-degenerate scenario

  1. Death Receptor 6 Promotes Wallerian Degeneration in Peripheral Axons.

    Science.gov (United States)

    Gamage, Kanchana K; Cheng, Irene; Park, Rachel E; Karim, Mardeen S; Edamura, Kazusa; Hughes, Christopher; Spano, Anthony J; Erisir, Alev; Deppmann, Christopher D

    2017-03-20

    Axon degeneration during development is required to sculpt a functional nervous system and is also a hallmark of pathological insult, such as injury [1, 2]. Despite similar morphological characteristics, very little overlap in molecular mechanisms has been reported between pathological and developmental degeneration [3-5]. In the peripheral nervous system (PNS), developmental axon pruning relies on receptor-mediated extrinsic degeneration mechanisms to determine which axons are maintained or degenerated [5-7]. Receptors have not been implicated in Wallerian axon degeneration; instead, axon autonomous, intrinsic mechanisms are thought to be the primary driver for this type of axon disintegration [8-10]. Here we survey the role of neuronally expressed, paralogous tumor necrosis factor receptor super family (TNFRSF) members in Wallerian degeneration. We find that an orphan receptor, death receptor 6 (DR6), is required to drive axon degeneration after axotomy in sympathetic and sensory neurons cultured in microfluidic devices. We sought to validate these in vitro findings in vivo using a transected sciatic nerve model. Consistent with the in vitro findings, DR6 -/- animals displayed preserved axons up to 4 weeks after injury. In contrast to phenotypes observed in Wld s and Sarm1 -/- mice, preserved axons in DR6 -/- animals display profound myelin remodeling. This indicates that deterioration of axons and myelin after axotomy are mechanistically distinct processes. Finally, we find that JNK signaling after injury requires DR6, suggesting a link between this novel extrinsic pathway and the axon autonomous, intrinsic pathways that have become established for Wallerian degeneration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Natural history of seminiferous tubule degeneration in Klinefelter syndrome

    DEFF Research Database (Denmark)

    Aksglaede, Lise; Wikström, Anne M; Rajpert-De Meyts, Ewa

    2006-01-01

    Klinefelter syndrome (47,XXY) is characterized by small, firm testis, gynaecomastia, azoospermia and hypergonadotropic hypogonadism. Degeneration of the seminiferous tubules in 47,XXY males is a well-described phenomenon. It begins in the fetus, progresses through infancy and accelerates dramatic......Klinefelter syndrome (47,XXY) is characterized by small, firm testis, gynaecomastia, azoospermia and hypergonadotropic hypogonadism. Degeneration of the seminiferous tubules in 47,XXY males is a well-described phenomenon. It begins in the fetus, progresses through infancy and accelerates...

  3. [Depression in Patients with Age-Related Macular Degeneration].

    Science.gov (United States)

    Narváez, Yamile Reveiz; Gómez-Restrepo, Carlos

    2012-09-01

    Age-related macular degeneration is a cause for disability in the elderly since it greatly affects their quality of life and increases depression likelihood. This article discusses the negative effect depression has on patients with age-related macular degeneration and summarizes the interventions available for decreasing their depression index. Copyright © 2012 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

  4. Phonon emission in a degenerate semiconductor at low lattice temperatures

    International Nuclear Information System (INIS)

    Midday, S.; Nag, S.; Bhattacharya, D.P.

    2015-01-01

    The characteristics of phonon growth in a degenerate semiconductor at low lattice temperatures have been studied for inelastic interaction of non-equilibrium electrons with the intravalley acoustic phonons. The energy of the phonon and the full form of the phonon distribution are taken into account. The results reveal significant changes in the growth characteristics compared to the same for a non-degenerate material

  5. Posterior Lattice Degeneration Characterized by Spectral Domain Optical Tomography

    OpenAIRE

    Manjunath, Varsha; Taha, Mohammed; Fujimoto, James G.; Duker, Jay S.

    2011-01-01

    PURPOSE: To utilize high-resolution spectral domain optical coherence tomography (SD-OCT) in the characterization of retinal and vitreal morphological changes overlying posterior lattice degeneration. METHODS: A cross-sectional, retrospective analysis was performed on 13 eyes of 13 nonconsecutive subjects with posterior lattice degeneration seen at the New England Eye Center, Tufts Medical Center between October 2009 and January 2010. SD-OCT images taken through the region of latti...

  6. A CTRP5 gene S163R mutation knock-in mouse model for late-onset retinal degeneration.

    Science.gov (United States)

    Chavali, Venkata R M; Khan, Naheed W; Cukras, Catherine A; Bartsch, Dirk-Uwe; Jablonski, Monica M; Ayyagari, Radha

    2011-05-15

    Late-onset retinal macular degeneration (L-ORD) is an autosomal dominant inherited disorder caused by a single missense mutation (S163R) in the CTRP5/C1QTNF5 protein. Early phenotypic features of L-ORD include: dark adaptation abnormalities, nyctalopia, and drusen deposits in the peripheral macular region. Apart from posterior segment abnormalities, these patients also develop abnormally long anterior lens zonules. In the sixth decade of life the rod and cone function declines, accompanied by electroretinogram (ERG) abnormalities. Some patients also develop choroidal neovascularization and glaucoma. In order to understand the disease pathology and mechanisms involved in retinal dystrophy, we generated a knock-in (Ctrp5(+/-)) mouse model carrying the disease-associated mutation in the mouse Ctrp5/C1QTNF5 gene. These mice develop slower rod-b wave recovery consistent with early dark adaptation abnormalities, accumulation of hyperautofluorescence spots, retinal pigment epithelium abnormalities, drusen, Bruch's membrane abnormalities, loss of photoreceptors, and retinal vascular leakage. The Ctrp5(+/-) mice, which have most of the pathological features of age-related macular degeneration, are unique and may serve as a valuable model both to understand the molecular pathology of late-onset retinal degeneration and to evaluate therapies.

  7. SU-C-207B-03: A Geometrical Constrained Chan-Vese Based Tumor Segmentation Scheme for PET

    International Nuclear Information System (INIS)

    Chen, L; Zhou, Z; Wang, J

    2016-01-01

    Purpose: Accurate segmentation of tumor in PET is challenging when part of tumor is connected with normal organs/tissues with no difference in intensity. Conventional segmentation methods, such as thresholding or region growing, cannot generate satisfactory results in this case. We proposed a geometrical constrained Chan-Vese based scheme to segment tumor in PET for this special case by considering the similarity between two adjacent slices. Methods: The proposed scheme performs segmentation in a slice-by-slice fashion where an accurate segmentation of one slice is used as the guidance for segmentation of rest slices. For a slice that the tumor is not directly connected to organs/tissues with similar intensity values, a conventional clustering-based segmentation method under user’s guidance is used to obtain an exact tumor contour. This is set as the initial contour and the Chan-Vese algorithm is applied for segmenting the tumor in the next adjacent slice by adding constraints of tumor size, position and shape information. This procedure is repeated until the last slice of PET containing tumor. The proposed geometrical constrained Chan-Vese based algorithm was implemented in Matlab and its performance was tested on several cervical cancer patients where cervix and bladder are connected with similar activity values. The positive predictive values (PPV) are calculated to characterize the segmentation accuracy of the proposed scheme. Results: Tumors were accurately segmented by the proposed method even when they are connected with bladder in the image with no difference in intensity. The average PPVs were 0.9571±0.0355 and 0.9894±0.0271 for 17 slices and 11 slices of PET from two patients, respectively. Conclusion: We have developed a new scheme to segment tumor in PET images for the special case that the tumor is quite similar to or connected to normal organs/tissues in the image. The proposed scheme can provide a reliable way for segmenting tumors.

  8. SU-C-207B-03: A Geometrical Constrained Chan-Vese Based Tumor Segmentation Scheme for PET

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L; Zhou, Z; Wang, J [UT Southwestern Medical Center, Dallas, TX (United States)

    2016-06-15

    Purpose: Accurate segmentation of tumor in PET is challenging when part of tumor is connected with normal organs/tissues with no difference in intensity. Conventional segmentation methods, such as thresholding or region growing, cannot generate satisfactory results in this case. We proposed a geometrical constrained Chan-Vese based scheme to segment tumor in PET for this special case by considering the similarity between two adjacent slices. Methods: The proposed scheme performs segmentation in a slice-by-slice fashion where an accurate segmentation of one slice is used as the guidance for segmentation of rest slices. For a slice that the tumor is not directly connected to organs/tissues with similar intensity values, a conventional clustering-based segmentation method under user’s guidance is used to obtain an exact tumor contour. This is set as the initial contour and the Chan-Vese algorithm is applied for segmenting the tumor in the next adjacent slice by adding constraints of tumor size, position and shape information. This procedure is repeated until the last slice of PET containing tumor. The proposed geometrical constrained Chan-Vese based algorithm was implemented in Matlab and its performance was tested on several cervical cancer patients where cervix and bladder are connected with similar activity values. The positive predictive values (PPV) are calculated to characterize the segmentation accuracy of the proposed scheme. Results: Tumors were accurately segmented by the proposed method even when they are connected with bladder in the image with no difference in intensity. The average PPVs were 0.9571±0.0355 and 0.9894±0.0271 for 17 slices and 11 slices of PET from two patients, respectively. Conclusion: We have developed a new scheme to segment tumor in PET images for the special case that the tumor is quite similar to or connected to normal organs/tissues in the image. The proposed scheme can provide a reliable way for segmenting tumors.

  9. Extraosseous Gaucher cell deposition without adjacent bone involvement.

    Science.gov (United States)

    Meyer, Brendan J; Mills, Anne M; Gaskin, Cree M

    2014-10-01

    Extraosseous Gaucher cell deposits are a rare complication of Gaucher disease that can mimic malignancy. We describe a case of Gaucher cell deposition in the subcutaneous soft tissues overlying the lower thoracic spine in an 18-year-old woman with known type III Gaucher disease. This case is unique in the literature because this subcutaneous Gaucher mass was not associated with extension from underlying bone involvement or clear lymph node origin. It demonstrated no discernible continuity with the adjacent thoracic spinous processes, the cortices of which appeared intact. Although patients with Gaucher disease are at increased risk of malignancy, Gaucher cell deposition should remain a differential consideration for soft tissue masses with or without adjacent bone involvement in patients with known Gaucher disease.

  10. A new nuclear safety programme for areas adjacent to Finland

    International Nuclear Information System (INIS)

    Varjoranta, T.

    1997-01-01

    The projects aimed at improving nuclear and radiation safety in areas adjacent to Finland have been compiled into one programme. The purpose of the programme is to promote activities that minimise accident risks at nuclear power plants and that improve preparedness for situations involving a risk. Nuclear materials are also to be kept under strict control. In the last few years, nuclear and radiation safety has clearly improved in areas adjacent to Finland. But work is still needed to reduce the remaining risks. The Finnish support programme comprises two very definite functions. On one hand, the programme acts as a catalyst for projects launched by the Russians themselves or by the Western partners together, and strives to pave the way for international financing projects. On the other hand, assistance is given as direct support for certain hand-picked projects. (orig.)

  11. Segmental vitiligo with segmental morphea: An autoimmune link?

    Directory of Open Access Journals (Sweden)

    Pravesh Yadav

    2014-01-01

    Full Text Available An 18-year old girl with segmental vitiligo involving the left side of the trunk and left upper limb with segmental morphea involving the right side of trunk and right upper limb without any deeper involvement is illustrated. There was no history of preceding drug intake, vaccination, trauma, radiation therapy, infection, or hormonal therapy. Family history of stable vitiligo in her brother and a history of type II diabetes mellitus in the father were elicited. Screening for autoimmune diseases and antithyroid antibody was negative. An autoimmune link explaining the co-occurrence has been proposed. Cutaneous mosiacism could explain the presence of both the pathologies in a segmental distribution.

  12. The prevalence of sacroiliac joint degeneration in asymptomatic adults.

    Science.gov (United States)

    Eno, Jonathan-James T; Boone, Christopher R; Bellino, Michael J; Bishop, Julius A

    2015-06-03

    Degenerative changes of the sacroiliac joint have been implicated as a cause of lower back pain in adults. The purpose of this study was to determine the prevalence of sacroiliac joint degeneration in asymptomatic patients. Five hundred consecutive pelvic computed tomography (CT) scans, made at a tertiary-care medical center, of patients with no history of pain in the lower back or pelvic girdle were retrospectively reviewed and analyzed for degenerative changes of the sacroiliac joint. After exclusion criteria were applied, 373 CT scans (746 sacroiliac joints) were evaluated for degenerative changes. Regression analysis was used to determine the association between age and the degree of sacroiliac joint degeneration. The prevalence of sacroiliac joint degeneration was 65.1%, with substantial degeneration occurring in 30.5% of asymptomatic subjects. The prevalence steadily increased with age, with 91% of subjects in the ninth decade of life displaying degenerative changes. Radiographic evidence of sacroiliac joint degeneration is highly prevalent in the asymptomatic population and is associated with age. Caution must be exercised when attributing lower back or pelvic girdle pain to sacroiliac joint degeneration seen on imaging. Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

  13. Risk of retinal detachment in patients with lattice degeneration.

    Science.gov (United States)

    Sasaki, K; Ideta, H; Yonemoto, J; Tanaka, S; Hirose, A; Oka, C

    1998-01-01

    To determine the risk of retinal detachment in patients with lattice degeneration of the retina, we statistically analyzed the incidence of retinal detachment in these patients. The data of hospital patients with retinal detachment associated with lattice degeneration in Kumamoto Prefecture, Japan, in 1990 were collected. The prevalence of lattice degeneration in Kumamoto was reported to be 9.5% in 1980. Based on population data from the 1990 census, the cumulative incidence of retinal detachment associated with lattice degeneration was calculated in this study. Among 1,840,000 residents in Kumamoto, there were 110 patients with retinal detachment associated with lattice degeneration; 72 with detachment resulting from tractional tears (tears), and 38 with detachment from atrophic holes. The cumulative incidence of retinal detachment from atrophic holes was 1.5% at the age of 40 years; from tears it was 3.6% at the age of 80 years. The cumulative incidence of detachment from both atrophic holes and tears was 5.3% at the age of 80 years. The results of this study are useful for clarifying the natural course of lattice degeneration.

  14. Posterior lattice degeneration characterized by spectral domain optical coherence tomography.

    Science.gov (United States)

    Manjunath, Varsha; Taha, Mohammed; Fujimoto, James G; Duker, Jay S

    2011-03-01

    The purpose of this study was to use high-resolution spectral domain optical coherence tomography in the characterization of retinal and vitreal morphological changes overlying posterior lattice degeneration. A cross-sectional retrospective analysis was performed on 13 eyes of 13 nonconsecutive subjects with posterior lattice degeneration seen at the New England Eye Center, Tufts Medical Center between October 2009 and January 2010. Spectral domain optical coherence tomography images taken through the region of lattice degeneration were qualitatively analyzed. Four characteristic changes of the retina and vitreous were seen in the 13 eyes with lattice degeneration: 1) anterior/posterior U-shaped vitreous traction; 2) retinal breaks; 3) focal retinal thinning; and 4) vitreous membrane formation. The morphologic appearance of vitreous traction and retinal breaks were found to be consistent with previous histologic reports. It is possible to image posterior lattice degeneration in many eyes using spectral domain optical coherence tomography and to visualize the spectrum of retinal and vitreous changes throughout the area of lattice degeneration.

  15. OFD1, as a Ciliary Protein, Exhibits Neuroprotective Function in Photoreceptor Degeneration Models.

    Directory of Open Access Journals (Sweden)

    Juan Wang

    Full Text Available Ofd1 is a newly identified causative gene for Retinitis pigmentosa (RP, a photoreceptor degenerative disease. This study aimed to examine Ofd1 localization in retina and further to investigate its function in photoreceptor degeneration models. Ofd1 localization in rat retina was examined using immunofluorescence. N-methyl-N-nitrosourea (MNU-induced rats and Royal College of Surgeons (RCS rats were used as photoreceptor degeneration models. The expression pattern of Ofd1, other ciliary associated genes and Wnt signaling pathway genes were examined in rat models. Furthermore, pEGFP-Ofd1-CDS and pSUPER-Ofd1-shRNA were constructed to overexpress and knockdown the expression level in 661W and R28 cells. MNU was also used to induce cell death. Cilia formation was observed using immunocytochemistry (ICC. Reactive oxygen species (ROS were detected using the 2', 7'-Dichlorofluorescin diacetate (DCFH-DA assay. Apoptosis genes expression was examined using qRT-PCR, Western blotting and fluorescence-activated cell sorting (FACS. Ofd1 localized to outer segments of rat retina photoreceptors. Ofd1 and other ciliary proteins expression levels increased from the 1st and 4th postnatal weeks and decreased until the 6th week in the RCS rats, while their expression consistently decreased from the 1st and 7th day in the MNU rats. Moreover, Wnt signaling pathway proteins expression was significantly up-regulated in both rat models. Knockdown of Ofd1 expression resulted in a smaller population, shorter length of cell cilia, and lower cell viability. Ofd1 overexpression partially attenuated MNU toxic effects by reducing ROS levels and mitigating apoptosis. To the best of our knowledge, this is the first study demonstrating Ofd1 localization and its function in rat retina and in retinal degeneration rat models. Ofd1 plays a role in controlling photoreceptor cilium length and number. Importantly, it demonstrates a neuroprotective function by protecting the photoreceptor

  16. Fish species diversity and conservation in Beijing and adjacent areas

    OpenAIRE

    Chunguang Zhang; Yahui Zhao; Yingchun Xing; Ruilu Guo; Qing Zhang; Yun Feng; Enyuan Fan

    2011-01-01

    Based on field surveys between 2002 and 2010, and fish collections in the National Zoological Museum, Institute of Zoology, Chinese Academy of Sciences, a total of 93 wild fish species including 12 in-troduced species had been recorded in Beijing and adjacent areas. Eighty five of these species, including some migratory and estuarine fishes, are native to the region. Only 43 native wild species were collected in our field work from 2002 to 2010. Compared with the historical records, nearly 50...

  17. Plutonium in soil adjacent to Rocky Flats plant

    International Nuclear Information System (INIS)

    Hume, M.W.; Illsley, C.T.

    1979-01-01

    In 1975, lawsuits were filed claiming contaminated lands adjacent to the plant. Five remote as well as 89 sites on lands under litigation were sampled using four sampling techniques at each site. An additional 71 sites were sampled using the Rockwell International technique. No results approached the EPA proposed guideline screening level of 200 mCi/km 2 , although numerous sites to the last of the plant exceed 2 d/m/g (10 mCi/km 2 )

  18. The Benguela upwelling ecosystem lies adjacent to the south ...

    African Journals Online (AJOL)

    denise

    The Benguela upwelling ecosystem lies adjacent to the south-western coast of Africa, from southern Angola. (15°S) to Cape Agulhas (35°S; Fig. 1). Ecologically, it is split into separate northern and southern sub- systems by a zone of intense perennial upwelling near. Lüderitz (26–27.5°S; Shannon 1985). As is charac-.

  19. Differential charge-transfer cross sections for systems with energetically degenerate or near-degenerate channels

    International Nuclear Information System (INIS)

    Nguyen, H.; Bredy, R.; Camp, H.A.; DePaola, B.D.; Awata, T.

    2004-01-01

    Resolution plays a vital role in spectroscopic studies. In the usual recoil-ion momentum spectroscopy (RIMS), Q-value resolution is relied upon to distinguish between different collision channels: The better the Q-value resolution, the better one is able to resolve energetically similar channels. Although traditional COLTRIMS greatly improves Q-value resolution by cooling the target and thus greatly reducing the initial target momentum spread, the resolution of the technique is still limited by target temperature. However, with the recent development in RIMS, namely, magneto-optical trap recoil ion momentum spectroscopy (MOTRIMS) superior recoil ion momentum resolution as well as charge transfer measurements with laser excited targets have become possible. Through MOTRIMS, methods for the measurements of target excited state fraction and kinematically complete relative charge transfer cross sections have been developed, even for some systems having energetically degenerate or nearly degenerate channels. In the present work, the systems of interest having energy degeneracies or near degeneracies are Rb + , K + , and Li + colliding with trapped Rb(5l), where l=s and p

  20. Frontotemporal Lobar Degeneration and microRNAs

    Directory of Open Access Journals (Sweden)

    Paola ePiscopo

    2016-02-01

    Full Text Available Frontotemporal lobar degeneration (FTLD includes a spectrum of disorders characterized by changes of personality and social behaviour and, often, a gradual and progressive language dysfunction. In the last years, several efforts have been fulfilled in identifying both genetic mutations and pathological proteins associated with FTLD. The molecular bases undergoing the onset and progression of the disease remain still unknown. Recent literature prompts an involvement of RNA metabolism in FTLD, particularly miRNAs. Dysregulation of miRNAs in several disorders, including neurodegenerative diseases, and increasing importance of circulating miRNAs in different pathologies has suggested to implement the study of their possible application as biological markers and new therapeutic targets; moreover, miRNA-based therapy is becoming a powerful tool to deepen the function of a gene, the mechanism of a disease, and validate therapeutic targets. Regarding FTLD, different studies showed that miRNAs are playing an important role. For example, several reports have evaluated miRNA regulation of the progranulin gene suggesting that it is under their control, as described for miR-29b, miR-107 and miR-659. More recently, it has been demonstrated that TMEM106B gene, which protein is elevated in FTLD-TDP brains, is repressed by miR-132/212 cluster; this post-transcriptional mechanism increases intracellular levels of progranulin, affecting its pathways. These findings if confirmed could suggest that these microRNAs have a role as potential targets for some related-FTLD genes. In this review, we focus on the emerging roles of the miRNAs in the pathogenesis of FTLD.

  1. Symmetry breaking of adjacent tracks in perpendicular recording system

    International Nuclear Information System (INIS)

    Xie Huang; Wei Dan

    2007-01-01

    The track density increase in a perpendicular magnetic recording system is limited by the adjacent-track interference (ATI). In this work, a composite micromagnetic simulation model of the read/write process is developed to analyse ATI by the symmetry of signal and noise in two adjacent W = 60 nm tracks with the track pitch of the order of 100 nm. Based on the two-dimensional medium noise distribution of dibit recording, it is found that the noise in the first and later recorded tracks start to be asymmetric when the track pitch is lower than 2 W; if the read width is limited within 2/3 of the write width, the asymmetry of noise appears when the track pitch is less than 1.5 W. At higher recording densities, the signal-to-noise ratio degradation is mainly due to the noise caused by the interference from the signal of the adjacent track. Side writing can be effectively eliminated by the use of a guard band whose width is at least half the track width

  2. Using BRDFs for accurate albedo calculations and adjacency effect corrections

    Energy Technology Data Exchange (ETDEWEB)

    Borel, C.C.; Gerstl, S.A.W.

    1996-09-01

    In this paper the authors discuss two uses of BRDFs in remote sensing: (1) in determining the clear sky top of the atmosphere (TOA) albedo, (2) in quantifying the effect of the BRDF on the adjacency point-spread function and on atmospheric corrections. The TOA spectral albedo is an important parameter retrieved by the Multi-angle Imaging Spectro-Radiometer (MISR). Its accuracy depends mainly on how well one can model the surface BRDF for many different situations. The authors present results from an algorithm which matches several semi-empirical functions to the nine MISR measured BRFs that are then numerically integrated to yield the clear sky TOA spectral albedo in four spectral channels. They show that absolute accuracies in the albedo of better than 1% are possible for the visible and better than 2% in the near infrared channels. Using a simplified extensive radiosity model, the authors show that the shape of the adjacency point-spread function (PSF) depends on the underlying surface BRDFs. The adjacency point-spread function at a given offset (x,y) from the center pixel is given by the integral of transmission-weighted products of BRDF and scattering phase function along the line of sight.

  3. Interactive and scale invariant segmentation of the rectum/sigmoid via user-defined templates

    Science.gov (United States)

    Lüddemann, Tobias; Egger, Jan

    2016-03-01

    Among all types of cancer, gynecological malignancies belong to the 4th most frequent type of cancer among women. Besides chemotherapy and external beam radiation, brachytherapy is the standard procedure for the treatment of these malignancies. In the progress of treatment planning, localization of the tumor as the target volume and adjacent organs of risks by segmentation is crucial to accomplish an optimal radiation distribution to the tumor while simultaneously preserving healthy tissue. Segmentation is performed manually and represents a time-consuming task in clinical daily routine. This study focuses on the segmentation of the rectum/sigmoid colon as an Organ-At-Risk in gynecological brachytherapy. The proposed segmentation method uses an interactive, graph-based segmentation scheme with a user-defined template. The scheme creates a directed two dimensional graph, followed by the minimal cost closed set computation on the graph, resulting in an outlining of the rectum. The graphs outline is dynamically adapted to the last calculated cut. Evaluation was performed by comparing manual segmentations of the rectum/sigmoid colon to results achieved with the proposed method. The comparison of the algorithmic to manual results yielded to a Dice Similarity Coefficient value of 83.85+/-4.08%, in comparison to 83.97+/-8.08% for the comparison of two manual segmentations of the same physician. Utilizing the proposed methodology resulted in a median time of 128 seconds per dataset, compared to 300 seconds needed for pure manual segmentation.

  4. Multi-atlas pancreas segmentation: Atlas selection based on vessel structure.

    Science.gov (United States)

    Karasawa, Ken'ichi; Oda, Masahiro; Kitasaka, Takayuki; Misawa, Kazunari; Fujiwara, Michitaka; Chu, Chengwen; Zheng, Guoyan; Rueckert, Daniel; Mori, Kensaku

    2017-07-01

    Automated organ segmentation from medical images is an indispensable component for clinical applications such as computer-aided diagnosis (CAD) and computer-assisted surgery (CAS). We utilize a multi-atlas segmentation scheme, which has recently been used in different approaches in the literature to achieve more accurate and robust segmentation of anatomical structures in computed tomography (CT) volume data. Among abdominal organs, the pancreas has large inter-patient variability in its position, size and shape. Moreover, the CT intensity of the pancreas closely resembles adjacent tissues, rendering its segmentation a challenging task. Due to this, conventional intensity-based atlas selection for pancreas segmentation often fails to select atlases that are similar in pancreas position and shape to those of the unlabeled target volume. In this paper, we propose a new atlas selection strategy based on vessel structure around the pancreatic tissue and demonstrate its application to a multi-atlas pancreas segmentation. Our method utilizes vessel structure around the pancreas to select atlases with high pancreatic resemblance to the unlabeled volume. Also, we investigate two types of applications of the vessel structure information to the atlas selection. Our segmentations were evaluated on 150 abdominal contrast-enhanced CT volumes. The experimental results showed that our approach can segment the pancreas with an average Jaccard index of 66.3% and an average Dice overlap coefficient of 78.5%. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Smarandachely Adjacent-Vertex-Distinguishing Proper Edge Chromatic Number of Cm∨Kn

    OpenAIRE

    Shunqin Liu

    2016-01-01

    According to different conditions, researchers have defined a great deal of coloring problems and the corresponding chromatic numbers. Such as, adjacent-vertex-distinguishing total chromatic number, adjacent-vertex-distinguishing proper edge chromatic number, smarandachely-adjacent-vertex-distinguishing proper edge chromatic number, smarandachely-adjacent-vertex-distinguishing proper total chromatic number. And we focus on the smarandachely adjacent-vertex-distinguishing proper edge chromatic...

  6. Segmental translation after lumbar total disc replacement using Prodisc-L®: associated factors and relation to facet arthrosis.

    Science.gov (United States)

    Shin, Myung H; Ryu, Kyeong S; Rathi, Nitesh K; Park, Chun K

    2017-02-01

    Segmental translation after lumbar total disc replacement (TDR) with ProDisc-L® prosthesis frequently observed radiographic findings during follow-up period. However its precise pathomechanism and relation with facet arthrosis have not been investigated yet. This study was performed to evaluate possible factors that affect postoperative segmental translation and to identify its relation with facet joint degeneration after lumbar TDR using ProDisc-L® prosthesis. Thirty-five consecutive patients, who underwent lumbar TDR using ProDisc-L®, completed minimum 24 months follow-up. Segmental translation was assessed postoperatively at 1 month and at least at 24 months by using dynamic plain radiograph. Segmental translation was assessed in relation to patient age, sex, change of functional spinal unit (FSU) height, segmental range of motion (ROM), global lumbar ROM, implanted level, relative prosthesis size and prosthesis position. The comparison of segmental translation between progressive facet arthrosis (PFA) group and non-PFA group was also made. The mean segmental translation was 0.49±0.49 mm at 1 month after surgery and showed significant increase to 0.83±0.78 mm at last follow-up (P=0.014). Change of FSU height, segmental ROM, global lumbar ROM, implanted level and relative size of prosthesis were the significant factors among the variables related to segmental translation that authors assessed (P=0.032, P=0.000, P=0.001, P=0.046 and P=0.042, respectively). There was no significant intergroup difference of mean segmental translation between PFA group and non-PFA group (P=0.586). This study demonstrates that segmental translation after TDR using ProDisc-L® has significant relations with change of FSU height, segmental ROM, global lumbar ROM, implanted level and relative size of prosthesis. With the intergroup comparison, PFA group did not show significant higher segmental translation than non-PFA group.

  7. Using Predictability for Lexical Segmentation.

    Science.gov (United States)

    Çöltekin, Çağrı

    2017-09-01

    This study investigates a strategy based on predictability of consecutive sub-lexical units in learning to segment a continuous speech stream into lexical units using computational modeling and simulations. Lexical segmentation is one of the early challenges during language acquisition, and it has been studied extensively through psycholinguistic experiments as well as computational methods. However, despite strong empirical evidence, the explicit use of predictability of basic sub-lexical units in models of segmentation is underexplored. This paper presents an incremental computational model of lexical segmentation for exploring the usefulness of predictability for lexical segmentation. We show that the predictability cue is a strong cue for segmentation. Contrary to earlier reports in the literature, the strategy yields state-of-the-art segmentation performance with an incremental computational model that uses only this particular cue in a cognitively plausible setting. The paper also reports an in-depth analysis of the model, investigating the conditions affecting the usefulness of the strategy. Copyright © 2016 Cognitive Science Society, Inc.

  8. Risk factors of age-related macular degeneration in Argentina

    Directory of Open Access Journals (Sweden)

    María Eugenia Nano

    2013-04-01

    Full Text Available PURPOSES: To assess the risk factors of age-related macular degeneration in Argentina using a case-control study. METHODS: Surveys were used for subjects' antioxidant intake, age/gender, race, body mass index, hypertension, diabetes (and type of treatment, smoking, sunlight exposure, red meat consumption, fish consumption, presence of age-related macular degeneration and family history of age-related macular degeneration. Main effects models for logistic regression and ordinal logistic regression were used to analyze the results. RESULTS: There were 175 cases and 175 controls with a mean age of 75.4 years and 75.5 years, respectively, of whom 236 (67.4% were female. Of the cases with age-related macular degeneration, 159 (45.4% had age-related macular degeneration in their left eyes, 154 (44.0% in their right eyes, and 138 (39.4% in both eyes. Of the cases with age-related macular degeneration in their left eyes, 47.8% had the dry type, 40.3% had the wet type, and the type was unknown for 11.9%. The comparable figures for right eyes were: 51.9%, 34.4%, and 13.7%, respectively. The main effects model was dominated by higher sunlight exposure (OR [odds ratio]: 3.3 and a family history of age-related macular degeneration (OR: 4.3. Other factors included hypertension (OR: 2.1, smoking (OR: 2.2, and being of the Mestizo race, which lowered the risk of age-related macular degeneration (OR: 0.40. Red meat/fish consumption, body mass index, and iris color did not have an effect. Higher age was associated with progression to more severe age-related macular degeneration. CONCLUSION: Sunlight exposure, family history of age-related macular degeneration, and an older age were the significant risk factors. There may be other variables, as the risk was not explained very well by the existing factors. A larger sample may produce different and better results.

  9. The Hierarchy of Segment Reports

    Directory of Open Access Journals (Sweden)

    Danilo Dorović

    2015-05-01

    Full Text Available The article presents an attempt to find the connection between reports created for managers responsible for different business segments. With this purpose, the hierarchy of the business reporting segments is proposed. This can lead to better understanding of the expenses under common responsibility of more than one manager since these expenses should be in more than one report. The structure of cost defined per business segment hierarchy with the aim of new, unusual but relevant cost structure for management can be established. Both could potentially bring new information benefits for management in the context of profit reporting.

  10. Segmental dilatation of the ileum

    Directory of Open Access Journals (Sweden)

    Tune-Yie Shih

    2017-01-01

    Full Text Available A 2-year-old boy was sent to the emergency department with the chief problem of abdominal pain for 1 day. He was just discharged from the pediatric ward with the diagnosis of mycoplasmal pneumonia and paralytic ileus. After initial examinations and radiographic investigations, midgut volvulus was impressed. An emergency laparotomy was performed. Segmental dilatation of the ileum with volvulus was found. The operative procedure was resection of the dilated ileal segment with anastomosis. The postoperative recovery was uneventful. The unique abnormality of gastrointestinal tract – segmental dilatation of the ileum, is described in details and the literature is reviewed.

  11. Structure of stable degeneration of K3 surfaces into pairs of rational elliptic surfaces

    OpenAIRE

    Kimura, Yusuke

    2018-01-01

    F-theory/heterotic duality is formulated in the stable degeneration limit of a K3 fibration on the F-theory side. In this note, we analyze the structure of the stable degeneration limit. We discuss whether stable degeneration exists for pairs of rational elliptic surfaces. We demonstrate that, when two rational elliptic surfaces have an identical complex structure, stable degeneration always exists. We provide an equation that systematically describes the stable degeneration of a K3 surface i...

  12. Computer aided vertebral visualization and analysis: a methodology using the sand rat, a small animal model of disc degeneration

    Directory of Open Access Journals (Sweden)

    Hanley Edward N

    2003-03-01

    Full Text Available Abstract Background The purpose of this study is to present an automated system that analyzes digitized x-ray images of small animal spines identifying the effects of disc degeneration. The age-related disc and spine degeneration that occurs in the sand rat (Psammomys obesus has previously been documented radiologically; selected representative radiographs with age-related changes were used here to develop computer-assisted vertebral visualization/analysis techniques. Techniques presented here have the potential to produce quantitative algorithms that create more accurate and informative measurements in a time efficient manner. Methods Signal and image processing techniques were applied to digitized spine x-ray images the spine was segmented, and orientation and curvature determined. The image was segmented based on orientation changes of the spine; edge detection was performed to define vertebral boundaries. Once vertebrae were identified, a number of measures were introduced and calculated to retrieve information on the vertebral separation/orientation and sclerosis. Results A method is described which produces computer-generated quantitative measurements of vertebrae and disc spaces. Six sand rat spine radiographs illustrate applications of this technique. Results showed that this method can successfully automate calculation and analysis of vertebral length, vertebral spacing, vertebral angle, and can score sclerosis. Techniques also provide quantitative means to explore the relation between age and vertebral shape. Conclusions This method provides a computationally efficient system to analyze spinal changes during aging. Techniques can be used to automate the quantitative processing of vertebral radiographic images and may be applicable to human and other animal radiologic models of the aging/degenerating spine.

  13. Accounting for segment correlations in segmented gamma-ray scans

    International Nuclear Information System (INIS)

    Sheppard, G.A.; Prettyman, T.H.; Piquette, E.C.

    1994-01-01

    In a typical segmented gamma-ray scanner (SGS), the detector's field of view is collimated so that a complete horizontal slice or segment of the desired thickness is visible. Ordinarily, the collimator is not deep enough to exclude gamma rays emitted from sample volumes above and below the segment aligned with the collimator. This can lead to assay biases, particularly for certain radioactive-material distributions. Another consequence of the collimator's low aspect ratio is that segment assays at the top and bottom of the sample are biased low because the detector's field of view is not filled. This effect is ordinarily countered by placing the sample on a low-Z pedestal and scanning one or more segment thicknesses below and above the sample. This takes extra time, however, We have investigated a number of techniques that both account for correlated segments and correct for end effects in SGS assays. Also, we have developed an algorithm that facilitates estimates of assay precision. Six calculation methods have been compared by evaluating the results of thousands of simulated, assays for three types of gamma-ray source distribution and ten masses. We will report on these computational studies and their experimental verification

  14. Automated age-related macular degeneration classification in OCT using unsupervised feature learning

    Science.gov (United States)

    Venhuizen, Freerk G.; van Ginneken, Bram; Bloemen, Bart; van Grinsven, Mark J. J. P.; Philipsen, Rick; Hoyng, Carel; Theelen, Thomas; Sánchez, Clara I.

    2015-03-01

    Age-related Macular Degeneration (AMD) is a common eye disorder with high prevalence in elderly people. The disease mainly affects the central part of the retina, and could ultimately lead to permanent vision loss. Optical Coherence Tomography (OCT) is becoming the standard imaging modality in diagnosis of AMD and the assessment of its progression. However, the evaluation of the obtained volumetric scan is time consuming, expensive and the signs of early AMD are easy to miss. In this paper we propose a classification method to automatically distinguish AMD patients from healthy subjects with high accuracy. The method is based on an unsupervised feature learning approach, and processes the complete image without the need for an accurate pre-segmentation of the retina. The method can be divided in two steps: an unsupervised clustering stage that extracts a set of small descriptive image patches from the training data, and a supervised training stage that uses these patches to create a patch occurrence histogram for every image on which a random forest classifier is trained. Experiments using 384 volume scans show that the proposed method is capable of identifying AMD patients with high accuracy, obtaining an area under the Receiver Operating Curve of 0:984. Our method allows for a quick and reliable assessment of the presence of AMD pathology in OCT volume scans without the need for accurate layer segmentation algorithms.

  15. What are Segments in Google Analytics

    Science.gov (United States)

    Segments find all sessions that meet a specific condition. You can then apply this segment to any report in Google Analytics (GA). Segments are a way of identifying sessions and users while filters identify specific events, like pageviews.

  16. Automated segmentation of geographic atrophy using deep convolutional neural networks

    Science.gov (United States)

    Hu, Zhihong; Wang, Ziyuan; Sadda, SriniVas R.

    2018-02-01

    Geographic atrophy (GA) is an end-stage manifestation of the advanced age-related macular degeneration (AMD), the leading cause of blindness and visual impairment in developed nations. Techniques to rapidly and precisely detect and quantify GA would appear to be of critical importance in advancing the understanding of its pathogenesis. In this study, we develop an automated supervised classification system using deep convolutional neural networks (CNNs) for segmenting GA in fundus autofluorescene (FAF) images. More specifically, to enhance the contrast of GA relative to the background, we apply the contrast limited adaptive histogram equalization. Blood vessels may cause GA segmentation errors due to similar intensity level to GA. A tensor-voting technique is performed to identify the blood vessels and a vessel inpainting technique is applied to suppress the GA segmentation errors due to the blood vessels. To handle the large variation of GA lesion sizes, three deep CNNs with three varying sized input image patches are applied. Fifty randomly chosen FAF images are obtained from fifty subjects with GA. The algorithm-defined GA regions are compared with manual delineation by a certified grader. A two-fold cross-validation is applied to evaluate the algorithm performance. The mean segmentation accuracy, true positive rate (i.e. sensitivity), true negative rate (i.e. specificity), positive predictive value, false discovery rate, and overlap ratio, between the algorithm- and manually-defined GA regions are 0.97 +/- 0.02, 0.89 +/- 0.08, 0.98 +/- 0.02, 0.87 +/- 0.12, 0.13 +/- 0.12, and 0.79 +/- 0.12 respectively, demonstrating a high level of agreement.

  17. Segmentation of the geographic atrophy in spectral-domain optical coherence tomography and fundus autofluorescence images.

    Science.gov (United States)

    Hu, Zhihong; Medioni, Gerard G; Hernandez, Matthias; Hariri, Amirhossein; Wu, Xiaodong; Sadda, Srinivas R

    2013-12-30

    Geographic atrophy (GA) is the atrophic late-stage manifestation of age-related macular degeneration (AMD), which may result in severe vision loss and blindness. The purpose of this study was to develop a reliable, effective approach for GA segmentation in both spectral-domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF) images using a level set-based approach and to compare the segmentation performance in the two modalities. To identify GA regions in SD-OCT images, three retinal surfaces were first segmented in volumetric SD-OCT images using a double-surface graph search scheme. A two-dimensional (2-D) partial OCT projection image was created from the segmented choroid layer. A level set approach was applied to segment the GA in the partial OCT projection image. In addition, the algorithm was applied to FAF images for the GA segmentation. Twenty randomly chosen macular SD-OCT (Zeiss Cirrus) volumes and 20 corresponding FAF (Heidelberg Spectralis) images were obtained from 20 subjects with GA. The algorithm-defined GA region was compared with consensus manual delineation performed by certified graders. The mean Dice similarity coefficients (DSC) between the algorithm- and manually defined GA regions were 0.87 ± 0.09 in partial OCT projection images and 0.89 ± 0.07 in registered FAF images. The area correlations between them were 0.93 (P segment GA regions in both SD-OCT and FAF images. This approach demonstrated good agreement between the algorithm- and manually defined GA regions within each single modality. The GA segmentation in FAF images performed better than in partial OCT projection images. Across the two modalities, the GA segmentation presented reasonable agreement.

  18. CLG for Automatic Image Segmentation

    OpenAIRE

    Christo Ananth; S.Santhana Priya; S.Manisha; T.Ezhil Jothi; M.S.Ramasubhaeswari

    2017-01-01

    This paper proposes an automatic segmentation method which effectively combines Active Contour Model, Live Wire method and Graph Cut approach (CLG). The aim of Live wire method is to provide control to the user on segmentation process during execution. Active Contour Model provides a statistical model of object shape and appearance to a new image which are built during a training phase. In the graph cut technique, each pixel is represented as a node and the distance between those nodes is rep...

  19. Market segmentation, targeting and positioning

    OpenAIRE

    Camilleri, Mark Anthony

    2017-01-01

    Businesses may not be in a position to satisfy all of their customers, every time. It may prove difficult to meet the exact requirements of each individual customer. People do not have identical preferences, so rarely does one product completely satisfy everyone. Many companies may usually adopt a strategy that is known as target marketing. This strategy involves dividing the market into segments and developing products or services to these segments. A target marketing strategy is focused on ...

  20. A Gaussian process and derivative spectral-based algorithm for red blood cell segmentation

    Science.gov (United States)

    Xue, Yingying; Wang, Jianbiao; Zhou, Mei; Hou, Xiyue; Li, Qingli; Liu, Hongying; Wang, Yiting

    2017-07-01

    As an imaging technology used in remote sensing, hyperspectral imaging can provide more information than traditional optical imaging of blood cells. In this paper, an AOTF based microscopic hyperspectral imaging system is used to capture hyperspectral images of blood cells. In order to achieve the segmentation of red blood cells, Gaussian process using squared exponential kernel function is applied first after the data preprocessing to make the preliminary segmentation. The derivative spectrum with spectral angle mapping algorithm is then applied to the original image to segment the boundary of cells, and using the boundary to cut out cells obtained from the Gaussian process to separated adjacent cells. Then the morphological processing method including closing, erosion and dilation is applied so as to keep adjacent cells apart, and by applying median filtering to remove noise points and filling holes inside the cell, the final segmentation result can be obtained. The experimental results show that this method appears better segmentation effect on human red blood cells.

  1. Recognition Using Classification and Segmentation Scoring

    National Research Council Canada - National Science Library

    Kimball, Owen; Ostendorf, Mari; Rohlicek, Robin

    1992-01-01

    .... We describe an approach to connected word recognition that allows the use of segmental information through an explicit decomposition of the recognition criterion into classification and segmentation scoring...

  2. Statins for age-related macular degeneration.

    Science.gov (United States)

    Gehlbach, Peter; Li, Tianjing; Hatef, Elham

    2015-02-11

    Age-related macular degeneration (AMD) is a progressive late onset disorder of the macula affecting central vision. Age-related macular degeneration is the leading cause of blindness in people over 65 years in industrialized countries. Recent epidemiologic, genetic, and pathological evidence has shown AMD shares a number of risk factors with atherosclerosis, leading to the hypothesis that statins may exert protective effects in AMD. The objective of this review was to examine the effectiveness of statins compared with other treatments, no treatment, or placebo in delaying the onset and progression of AMD. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2014), EMBASE (January 1980 to June 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to June 2014), PubMed (January 1946 to June 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 5 June 2014. We included randomized controlled trials (RCTs) that compared statins with other treatments, no treatment, or placebo in participants who were either susceptible to or diagnosed as having early stages of AMD. We used standard methodological procedures expected by The Cochrane Collaboration. Two authors independently evaluated the search results against the selection criteria, abstracted data, and assessed risk of bias. We did not perform meta-analysis due to heterogeneity in the interventions and outcomes among the included studies. Two RCTs with 144 total participants met the selection criteria

  3. Microwave treatment of renal cell carcinoma adjacent to renal sinus.

    Science.gov (United States)

    Gao, Yongyan; Liang, Ping; Yu, Xiaoling; Yu, Jie; Cheng, Zhigang; Han, Zhiyu; Duan, Shaobo; Huang, Hui

    2016-11-01

    To evaluate the efficacy and safety of ultrasound (US)-guided percutaneous microwave ablation (MWA) for renal cell carcinoma (RCC) adjacent to renal sinus. This retrospective study included 41 patients who underwent US-guided percutaneous MWA of 41 RCCs adjacent to the renal sinus from April 2006 to December 2015. Contrast-enhanced images of US and computed tomography (CT) or magnetic resonance (MR) imaging were performed at pre-ablation and 1day, 1 month, 3 months, and every 6 months after ablation. Initial ablation success (IAS), disease-free survival (DFS), RCC-related survival (RRS), and overall survival (OS) were recorded at the follow-up visits. IAS was achieved in 92.7% (38/41) of the study subjects. The IAS significantly differed between patients with RCCs ≤4cm (100%, 29/29) and RCCs >4cm (75%, 9/12, p=0.021). During the median follow-up of 37.6 (range, 3.0-97.3) months, the estimated 1-, 3-, and 5-year DFS of patients with an initial tumor of ≤4cm were 100%, 89.7%, and 81.5%, respectively. The 1-, 3-, and 5-year RRS were 100%, 93.3%, and 93.3%, respectively. The 1-, 3-, and 5-year OS were 97.1%, 87.8%, and 83.6%, respectively. The multivariate analysis using the Cox proportional hazard model revealed no independent predictor of recurrence among all the variables. There were no MWA-related deaths among the study subjects. One patient developed a retroperitoneal abscess after ablation. US-guided percutaneous MWA appears to be a promising method for RCCs adjacent to renal sinus, especially for tumors ≤4cm. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Osteoid Osteoma of Cervical Spine in two adjacent Vertebrae

    Directory of Open Access Journals (Sweden)

    MR Etemadifar

    2005-09-01

    Full Text Available Osteoid osteoma is a benign bone tumor, mainly seen in 10-30 years male. Spine is a relatively common site and almost always, posterior elements are involved. Plain X-Ray-, CT scan and Isotope scan help to identify and localize spine lesions. We described one 18 years old boy with 3 years low neck pain. Isotope scan, MRI and CT scan showed two lesions in C7 and T1. Gross inspection and histopathology examination confirmed osteoid osteoma in two adjacent vertebrae which has not been reported elsewhere in the literature. Key words: Osteoid Osteoma, Spine, Multifocal

  5. Microwave treatment of renal cell carcinoma adjacent to renal sinus

    International Nuclear Information System (INIS)

    Gao, Yongyan; Liang, Ping; Yu, Xiaoling; Yu, Jie; Cheng, Zhigang; Han, Zhiyu; Duan, Shaobo; Huang, Hui

    2016-01-01

    Highlights: • This study shows US-guided microwave ablation appears to be a promising method to treat renal cell carcinoma adjacent to renal sinus. • The estimated 1-, 3- and 5-year RCC-related survival were 100%, 93.3% and 93.3%, respectively. • The estimated 1-, 3- and 5-year overall survival were 97.1%, 87.8%, 83.6%, respectively. • For patients with RCC ≤4 cm, initial ablation success was 100% (29/29) and the estimated 5-year disease-free survival were 81.5%. - Abstract: Purpose: To evaluate the efficacy and safety of ultrasound (US)-guided percutaneous microwave ablation (MWA) for renal cell carcinoma (RCC) adjacent to renal sinus. Materials and methods: This retrospective study included 41 patients who underwent US-guided percutaneous MWA of 41 RCCs adjacent to the renal sinus from April 2006 to December 2015. Contrast-enhanced images of US and computed tomography (CT) or magnetic resonance (MR) imaging were performed at pre-ablation and 1 day, 1 month, 3 months, and every 6 months after ablation. Initial ablation success (IAS), disease-free survival (DFS), RCC-related survival (RRS), and overall survival (OS) were recorded at the follow-up visits. Results: IAS was achieved in 92.7% (38/41) of the study subjects. The IAS significantly differed between patients with RCCs ≤4 cm (100%, 29/29) and RCCs >4 cm (75%, 9/12, p = 0.021). During the median follow-up of 37.6 (range, 3.0–97.3) months, the estimated 1-, 3-, and 5-year DFS of patients with an initial tumor of ≤4 cm were 100%, 89.7%, and 81.5%, respectively. The 1-, 3-, and 5-year RRS were 100%, 93.3%, and 93.3%, respectively. The 1-, 3-, and 5-year OS were 97.1%, 87.8%, and 83.6%, respectively. The multivariate analysis using the Cox proportional hazard model revealed no independent predictor of recurrence among all the variables. There were no MWA-related deaths among the study subjects. One patient developed a retroperitoneal abscess after ablation. Conclusion: US-guided percutaneous MWA

  6. Microwave treatment of renal cell carcinoma adjacent to renal sinus

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yongyan, E-mail: gaoyongyan7@163.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Department of Ultrasound, The General Hospital of Chinese People’s Armed Police Forces, 69 Yongding Road, Beijing, 100039 (China); Liang, Ping, E-mail: liangping301@hotmail.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Yu, Xiaoling, E-mail: 784107477@qq.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Yu, Jie, E-mail: 1411495161@qq.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Cheng, Zhigang, E-mail: 13691367317@163.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Han, Zhiyu, E-mail: hanzhiyu122@163.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Duan, Shaobo, E-mail: Dustin2662@163.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China); Huang, Hui, E-mail: 309hh@sina.com [Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 (China)

    2016-11-15

    Highlights: • This study shows US-guided microwave ablation appears to be a promising method to treat renal cell carcinoma adjacent to renal sinus. • The estimated 1-, 3- and 5-year RCC-related survival were 100%, 93.3% and 93.3%, respectively. • The estimated 1-, 3- and 5-year overall survival were 97.1%, 87.8%, 83.6%, respectively. • For patients with RCC ≤4 cm, initial ablation success was 100% (29/29) and the estimated 5-year disease-free survival were 81.5%. - Abstract: Purpose: To evaluate the efficacy and safety of ultrasound (US)-guided percutaneous microwave ablation (MWA) for renal cell carcinoma (RCC) adjacent to renal sinus. Materials and methods: This retrospective study included 41 patients who underwent US-guided percutaneous MWA of 41 RCCs adjacent to the renal sinus from April 2006 to December 2015. Contrast-enhanced images of US and computed tomography (CT) or magnetic resonance (MR) imaging were performed at pre-ablation and 1 day, 1 month, 3 months, and every 6 months after ablation. Initial ablation success (IAS), disease-free survival (DFS), RCC-related survival (RRS), and overall survival (OS) were recorded at the follow-up visits. Results: IAS was achieved in 92.7% (38/41) of the study subjects. The IAS significantly differed between patients with RCCs ≤4 cm (100%, 29/29) and RCCs >4 cm (75%, 9/12, p = 0.021). During the median follow-up of 37.6 (range, 3.0–97.3) months, the estimated 1-, 3-, and 5-year DFS of patients with an initial tumor of ≤4 cm were 100%, 89.7%, and 81.5%, respectively. The 1-, 3-, and 5-year RRS were 100%, 93.3%, and 93.3%, respectively. The 1-, 3-, and 5-year OS were 97.1%, 87.8%, and 83.6%, respectively. The multivariate analysis using the Cox proportional hazard model revealed no independent predictor of recurrence among all the variables. There were no MWA-related deaths among the study subjects. One patient developed a retroperitoneal abscess after ablation. Conclusion: US-guided percutaneous MWA

  7. Hyperspectral image segmentation using a cooperative nonparametric approach

    Science.gov (United States)

    Taher, Akar; Chehdi, Kacem; Cariou, Claude

    2013-10-01

    In this paper a new unsupervised nonparametric cooperative and adaptive hyperspectral image segmentation approach is presented. The hyperspectral images are partitioned band by band in parallel and intermediate classification results are evaluated and fused, to get the final segmentation result. Two unsupervised nonparametric segmentation methods are used in parallel cooperation, namely the Fuzzy C-means (FCM) method, and the Linde-Buzo-Gray (LBG) algorithm, to segment each band of the image. The originality of the approach relies firstly on its local adaptation to the type of regions in an image (textured, non-textured), and secondly on the introduction of several levels of evaluation and validation of intermediate segmentation results before obtaining the final partitioning of the image. For the management of similar or conflicting results issued from the two classification methods, we gradually introduced various assessment steps that exploit the information of each spectral band and its adjacent bands, and finally the information of all the spectral bands. In our approach, the detected textured and non-textured regions are treated separately from feature extraction step, up to the final classification results. This approach was first evaluated on a large number of monocomponent images constructed from the Brodatz album. Then it was evaluated on two real applications using a respectively multispectral image for Cedar trees detection in the region of Baabdat (Lebanon) and a hyperspectral image for identification of invasive and non invasive vegetation in the region of Cieza (Spain). A correct classification rate (CCR) for the first application is over 97% and for the second application the average correct classification rate (ACCR) is over 99%.

  8. 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

  9. 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.

  10. Mechanisms of Distal Axonal Degeneration in Peripheral Neuropathies

    Science.gov (United States)

    Cashman, Christopher R.; Höke, Ahmet

    2015-01-01

    Peripheral neuropathy is a common complication of a variety of diseases and treatments, including diabetes, cancer chemotherapy, and infectious causes (HIV, hepatitis C, and Campylobacter jejuni). Despite the fundamental difference between these insults, peripheral neuropathy develops as a combination of just six primary mechanisms: altered metabolism, covalent modification, altered organelle function and reactive oxygen species formation, altered intracellular and inflammatory signaling, slowed axonal transport, and altered ion channel dynamics and expression. All of these pathways converge to lead to axon dysfunction and symptoms of neuropathy. The detailed mechanisms of axon degeneration itself have begun to be elucidated with studies of animal models with altered degeneration kinetics, including the slowed Wallerian degeneration (Wlds) and Sarmknockout animal models. These studies have shown axonal degeneration to occur througha programmed pathway of injury signaling and cytoskeletal degradation. Insights into the common disease insults that converge on the axonal degeneration pathway promise to facilitate the development of therapeutics that may be effective against other mechanisms of neurodegeneration. PMID:25617478

  11. LONGITUDINAL STRUCTURAL CHANGES IN LATE-ONSET RETINAL DEGENERATION.

    Science.gov (United States)

    Cukras, Catherine; Flamendorf, Jason; Wong, Wai T; Ayyagari, Radha; Cunningham, Denise; Sieving, Paul A

    2016-12-01

    To characterize longitudinal structural changes in early stages of late-onset retinal degeneration to investigate pathogenic mechanisms. Two affected siblings, both with a S163R missense mutation in the causative gene C1QTNF5, were followed for 8+ years. Color fundus photos, fundus autofluorescence images, near-infrared reflectance fundus images, and spectral domain optical coherence tomography scans were acquired during follow-up. Both patients, aged 45 and 50 years, had good visual acuities (>20/20) in the context of prolonged dark adaptation. Baseline color fundus photography demonstrated yellow-white, punctate lesions in the temporal macula that correlated with a reticular pattern on fundus autofluorescence and near-infrared reflectance imaging. Baseline spectral domain optical coherence tomography imaging revealed subretinal deposits that resemble reticular pseudodrusen described in age-related macular degeneration. During follow-up, these affected areas developed confluent thickening of the retinal pigment epithelial layer and disruption of the ellipsoid zone of photoreceptors before progressing to overt retinal pigment epithelium and outer retinal atrophy. Structural changes in early stages of late-onset retinal degeneration, revealed by multimodal imaging, resemble those of reticular pseudodrusen observed in age-related macular degeneration and other retinal diseases. Longitudinal follow-up of these lesions helps elucidate their progression to frank atrophy and may lend insight into the pathogenic mechanisms underlying diverse retinal degenerations.

  12. Deficiency of adaptive immunity does not interfere with Wallerian degeneration.

    Directory of Open Access Journals (Sweden)

    Christopher R Cashman

    Full Text Available Following injury, distal axons undergo the process of Wallerian degeneration, and then cell debris is cleared to create a permissive environment for axon regeneration. The innate and adaptive immune systems are believed to be critical for facilitating the clearance of myelin and axonal debris during this process. However, immunodeficient animal models are regularly used in transplantation studies investigating cell therapies to modulate the degenerative/regenerative response. Given the importance of the immune system in preparing a permissive environment for regeneration by clearing debris, animals lacking, in part or in full, a functional immune system may have an impaired ability to regenerate due to poor myelin clearance, and may, thus, be poor hosts to study modulators of regeneration and degeneration. To study this hypothesis, three different mouse models with impaired adaptive immunity were compared to wild type animals in their ability to degenerate axons and clear myelin debris one week following sciatic nerve transection. Immunofluorescent staining for axons and quantitation of axon density with nerve histomorphometry of the distal stump showed no consistent discrepancy between immunodeficient and wild type animals, suggesting axons tended to degenerate equally between the two groups. Debris clearance was assessed by macrophage density and relative myelin basic protein expression within the denervated nerve stump, and no consistent impairment of debris clearance was found. These data suggested deficiency of the adaptive immune system does not have a substantial effect on axon degeneration one week following axonal injury.

  13. Degenerative Pathways of Lumbar Motion Segments

    DEFF Research Database (Denmark)

    Jensen, Rikke K.; Kjaer, Per; Jensen, Tue S.

    2016-01-01

    pathways of degeneration based on scientific knowledge of disco-vertebral degeneration, and (iii) compare these clusters and degenerative pathways between samples. METHODS: We performed a secondary cross-sectional analysis on two dissimilar MRI samples collected in a hospital department: (1) data from...... pathways of degeneration. RESULTS: Six clusters of MRI findings were identified in each of the two samples. The content of the clusters in the two samples displayed some differences but had the same overall pattern of MRI findings. Although the hypothetical degenerative pathways identified in the two...... samples were not identical, the overall pattern of increasing degeneration within the pathways was the same. CONCLUSIONS: It was expected that different clusters could emerge from different samples, however, when organised into hypothetical pathways of degeneration, the overall pattern of increasing...

  14. Survey of roadside alien plants in Hawai`i Volcanoes National Park and adjacent residential areas 2001-2005

    Science.gov (United States)

    Bio, Keali'i F.; Pratt, Linda W.; Jacobi, James D.

    2012-01-01

    The sides of all paved roads of Hawai`i Volcanoes National Park (HAVO) were surveyed on foot in 2001 to 2005, and the roadside presence of 240 target invasive and potentially invasive alien plant species was recorded in mile-long increments. Buffer zones 5–10 miles (8–16 km) long along Highway 11 on either side of the Kīlauea and Kahuku Units of the park, as well as Wright Road that passed by the disjunct `Ōla`a Tract Unit, were included in the survey. Highway 11 is the primary road through the park and a major island thoroughfare. Three residential subdivisions adjacent to the park were similarly surveyed in 0.5–1 mile (0.8–1.6 km) intervals in 2003, and data were analyzed separately. Two roads to the east and northeast were also surveyed, but data from these disjunct areas were analyzed separately from park roads. In total, 174 of the target alien species were observed along HAVO roads and buffers, exclusive of residential areas, and the mean number of target aliens per mile surveyed was 20.6. Highway 11 and its buffer zones had the highest mean number of target alien plants per mile (26.7) of all park roads, and the Mauna Loa Strip Road had the lowest mean (11.7). Segments of Highway 11 adjacent to HAVO and Wright Road next to `Ōla`a Tract had mean numbers of target alien per mile (24–47) higher than those of any internal road. Alien plant frequencies were summarized for each road in HAVO. Fifteen new records of vascular plants for HAVO were observed and collected along park roads. An additional 28 alien plant species not known from HAVO were observed along the buffer segments of Highway 11 adjacent to the park. Within the adjacent residential subdivisions, 65 target alien plant species were sighted along roadsides. At least 15 potentially invasive species not currently found within HAVO were observed along residential roads, and several other species found there have been previously eliminated from the park or controlled to remnant populations

  15. The Degeneration of Meniscus Roots Is Accompanied by Fibrocartilage Formation, Which May Precede Meniscus Root Tears in Osteoarthritic Knees.

    Science.gov (United States)

    Park, Do Young; Min, Byoung-Hyun; Choi, Byung Hyune; Kim, Young Jick; Kim, Mijin; Suh-Kim, Haeyoung; Kim, Joon Ho

    2015-12-01

    Fibrocartilage metaplasia in tendons and ligaments is an adaptation to compression as well as a pathological feature during degeneration. Medial meniscus posterior roots are unique ligaments that resist multidirectional forces, including compression. To characterize the degeneration of medial meniscus posterior root tears in osteoarthritic knees, with an emphasis on fibrocartilage and calcification. Cross-sectional study; Level of evidence, 3. Samples of medial meniscus posterior roots were harvested from cadaveric specimens and patients during knee replacement surgery and grouped as follows: normal reference, no tear, partial tear, and complete tear. Degeneration was analyzed with histology, immunohistochemistry, and real-time polymerase chain reaction. Uniaxial tensile tests were performed on specimens with and without fibrocartilage. Quantifiable data were statistically analyzed by the Kruskal-Wallis test with the Dunn comparison test. Thirty, 28, and 42 samples harvested from 99 patients were allocated into the no tear, partial tear, and complete tear groups, respectively. Mean modified Bonar tendinopathy scores for each group were 3.97, 9.31, and 14.15, respectively, showing a higher degree of degeneration associated with the extent of the tear (P fibrocartilage according to the extent of the tear. Tear margins revealed fibrocartilage in 59.3% of partial tear samples and 76.2% of complete tear samples, with a distinctive cleavage-like shape. Root tears with a similar shape were induced within fibrocartilaginous areas during uniaxial tensile testing. Even in the no tear group, 56.7% of samples showed fibrocartilage in the anterior margin of the root, adjacent to the meniscus. An increased stained area of calcification and expression of the ectonucleotide pyrophosphatase/phosphodiesterase 1 gene were observed in the complete tear group compared with the no tear group (P Fibrocartilage and calcification increased in medial meniscus posterior roots, associated

  16. ORNAMENTAL PLANTS OF CHECHNYA AND ITS ADJACENT AREAS

    Directory of Open Access Journals (Sweden)

    Musa A. Taysumov

    2018-01-01

    Full Text Available Abstract. The aim of the research is to summarize the scattered information about the types of decorative flora of the Chechen Republic and adjacent territories; to identify highly resistant ornamental plants for cities and settlements of the North Caucasus and other territories of Russia. Discussion. Currently, in a variety of botanical gardens of the North Caucasus grows a large number of decorative plant species, widely used in green construction. However, not all species posses the quality to sufficient resist unfavorable conditions of the changed abiotic and biotic environment. Among the studied, the most valuable and promising for widespread introduction are the species of more than 122 taxa, the decorative effect of which is preserved throughout the year with no signs of aging. Many examples of the targeted use of herbs, tree species, lianas, bulbous plants were cited in the research. We give a large list of Caucasian species for growing on lawns, flowerbeds, flower gardens, alpine and stony mountains, roadsides and parks, urban parks, squares and alleys as a type of gardening. Their decorative properties, vitality, durability, life form and other bio-ecological features, attitude to abiotic factors (soil conditions, illumination, temperature, soil and atmospheric humidification conditions, etc. were taken into account. Conclusion. We give a large list of ornamental species and various planting techniques of specific species are introduced in conditions of Chechnya and its adjacent territories as well as the methods of implementing in the landscaping practice in other (middle and northern regions of Russia.

  17. Absorbed dose distribution analyses in irradiation with adjacent fields

    International Nuclear Information System (INIS)

    Cudalbu, C.; Onuc, C.; Andrada, S.

    2002-01-01

    Because the special irradiation technique with adjacent fields is the most used in the case of medulloblastoma treatment, we consider very important to specify some general information about medulloblastoma. This malignant disease has a large incidence in children with age between 5-7 years. This tumor usually originates in the cerebellum and is referred to as primitive undifferentiated tumor. It may spread contiguously to the cerebellar peduncle, floor of the fourth ventricle, into the cervical spine. In addition, it may spread via the cerebrospinal fluid intracranially and/or to the spinal cord. For this purpose it is necessary to perform a treatment technique with cranial tangential fields combined with adjacent fields for the entire spinal cord to achieve a perfect coverage of the zones with malignant cells. The treatment in this case is an association between surgery-radio-chemotherapy, where the radiotherapy has a very important roll and a curative purpose. This is due to the fact that the migration of malignant cells in the body can't be controlled by surgery. Because of this special irradiation technique used in medulloblastoma treatment, we chase to describe in this paper this complex type of irradiation where the implications of the beams divergence in doses distribution are essentials

  18. Calculations of the electrostatic potential adjacent to model phospholipid bilayers.

    Science.gov (United States)

    Peitzsch, R M; Eisenberg, M; Sharp, K A; McLaughlin, S

    1995-03-01

    We used the nonlinear Poisson-Boltzmann equation to calculate electrostatic potentials in the aqueous phase adjacent to model phospholipid bilayers containing mixtures of zwitterionic lipids (phosphatidylcholine) and acidic lipids (phosphatidylserine or phosphatidylglycerol). The aqueous phase (relative permittivity, epsilon r = 80) contains 0.1 M monovalent salt. When the bilayers contain equipotential surfaces are discrete domes centered over the negatively charged lipids and are approximately twice the value calculated using Debye-Hückel theory. When the bilayers contain > 25% acidic lipid, the -25 mV equipotential profiles are essentially flat and agree well with the values calculated using Gouy-Chapman theory. When the bilayers contain 100% acidic lipid, all of the equipotential surfaces are flat and agree with Gouy-Chapman predictions (including the -100 mV surface, which is located only 1 A from the outermost atoms). Even our model bilayers are not simple systems: the charge on each lipid is distributed over several atoms, these partial charges are non-coplanar, there is a 2 A ion-exclusion region (epsilon r = 80) adjacent to the polar headgroups, and the molecular surface is rough. We investigated the effect of these four factors using smooth (or bumpy) epsilon r = 2 slabs with embedded point charges: these factors had only minor effects on the potential in the aqueous phase.

  19. A coarse-to-fine approach for pericardial effusion localization and segmentation in chest CT scans

    Science.gov (United States)

    Liu, Jiamin; Chellamuthu, Karthik; Lu, Le; Bagheri, Mohammadhadi; Summers, Ronald M.

    2018-02-01

    Pericardial effusion on CT scans demonstrates very high shape and volume variability and very low contrast to adjacent structures. This inhibits traditional automated segmentation methods from achieving high accuracies. Deep neural networks have been widely used for image segmentation in CT scans. In this work, we present a two-stage method for pericardial effusion localization and segmentation. For the first step, we localize the pericardial area from the entire CT volume, providing a reliable bounding box for the more refined segmentation step. A coarse-scaled holistically-nested convolutional networks (HNN) model is trained on entire CT volume. The resulting HNN per-pixel probability maps are then threshold to produce a bounding box covering the pericardial area. For the second step, a fine-scaled HNN model is trained only on the bounding box region for effusion segmentation to reduce the background distraction. Quantitative evaluation is performed on a dataset of 25 CT scans of patient (1206 images) with pericardial effusion. The segmentation accuracy of our two-stage method, measured by Dice Similarity Coefficient (DSC), is 75.59+/-12.04%, which is significantly better than the segmentation accuracy (62.74+/-15.20%) of only using the coarse-scaled HNN model.

  20. Physical linkage of a human immunoglobulin heavy chain variable region gene segment to diversity and joining region elements

    International Nuclear Information System (INIS)

    Schroeder, H.W. Jr.; Walter, M.A.; Hofker, M.H.; Ebens, A.; Van Dijk, K.W.; Liao, L.C.; Cox, D.W.; Milner, E.C.B.; Perlmutter, R.M.

    1988-01-01

    Antibody genes are assembled from a series of germ-line gene segments that are juxtaposed during the maturation of B lymphocytes. Although diversification of the adult antibody repertoire results in large part from the combinatorial joining of these gene segments, a restricted set of antibody heavy chain variable (V H ), diversity (D H ), and joining (J H ) region gene segments appears preferentially in the human fetal repertoire. The authors report here that one of these early-expressed V H elements (termed V H 6) is the most 3' V H gene segment, positioned 77 kilobases on the 5' side of the J H locus and immediately adjacent to a set of previously described D H sequences. In addition to providing a physical map linking human V H , D H , and J H elements, these results support the view that the programmed development of the antibody V H repertoire is determined in part by the chromosomal position of these gene segments

  1. Cystic degeneration of liver malignancies. Study by US and CT

    Energy Technology Data Exchange (ETDEWEB)

    Kumada, Takashi; Nakano, Satoshi; Kitamura, Kimio; Watahiki, Hajime; Takeda, Isao

    1983-03-01

    CT and US were carried out on 81 patients with hepatocellular carcinoma, 20 patients with cholangiocellular carcinoma and 94 patients with metastatic liver cancer. 1) Cystic degeneration was observed in one with hepatocellular carcinoma (1.2%), one with cholangiocellular carcinoma (5.0%) and 12 with metastatic liver cancer (12.8%) by US, but this change was observed in only 5 by CT (1,0,4, respectively). Metastatic liver cancer showed the highest incidence among these tumors. 2) The characteristics of cystic degeneration of the liver tumors were thickened wall and irregularity of the inner surface of the wall. 3) Judging from macroscopic and histopathological findings, liquefactive necrosis in the tumors was shown as ''echoluent'' area. We concluded that cystic degeneration was one of the important findings in metastatic liver cancer and that careful observation by US and CT avoided the confusion with other hepatic cystic diseases.

  2. Quantization with maximally degenerate Poisson brackets: the harmonic oscillator!

    International Nuclear Information System (INIS)

    Nutku, Yavuz

    2003-01-01

    Nambu's construction of multi-linear brackets for super-integrable systems can be thought of as degenerate Poisson brackets with a maximal set of Casimirs in their kernel. By introducing privileged coordinates in phase space these degenerate Poisson brackets are brought to the form of Heisenberg's equations. We propose a definition for constructing quantum operators for classical functions, which enables us to turn the maximally degenerate Poisson brackets into operators. They pose a set of eigenvalue problems for a new state vector. The requirement of the single-valuedness of this eigenfunction leads to quantization. The example of the harmonic oscillator is used to illustrate this general procedure for quantizing a class of maximally super-integrable systems

  3. An iterative method for selecting degenerate multiplex PCR primers.

    Science.gov (United States)

    Souvenir, Richard; Buhler, Jeremy; Stormo, Gary; Zhang, Weixiong

    2007-01-01

    Single-nucleotide polymorphism (SNP) genotyping is an important molecular genetics process, which can produce results that will be useful in the medical field. Because of inherent complexities in DNA manipulation and analysis, many different methods have been proposed for a standard assay. One of the proposed techniques for performing SNP genotyping requires amplifying regions of DNA surrounding a large number of SNP loci. To automate a portion of this particular method, it is necessary to select a set of primers for the experiment. Selecting these primers can be formulated as the Multiple Degenerate Primer Design (MDPD) problem. The Multiple, Iterative Primer Selector (MIPS) is an iterative beam-search algorithm for MDPD. Theoretical and experimental analyses show that this algorithm performs well compared with the limits of degenerate primer design. Furthermore, MIPS outperforms an existing algorithm that was designed for a related degenerate primer selection problem.

  4. Natural history of seminiferous tubule degeneration in Klinefelter syndrome

    DEFF Research Database (Denmark)

    Aksglaede, Lise; Wikström, Anne M; Rajpert-De Meyts, Ewa

    2006-01-01

    Klinefelter syndrome (47,XXY) is characterized by small, firm testis, gynaecomastia, azoospermia and hypergonadotropic hypogonadism. Degeneration of the seminiferous tubules in 47,XXY males is a well-described phenomenon. It begins in the fetus, progresses through infancy and accelerates dramatic......Klinefelter syndrome (47,XXY) is characterized by small, firm testis, gynaecomastia, azoospermia and hypergonadotropic hypogonadism. Degeneration of the seminiferous tubules in 47,XXY males is a well-described phenomenon. It begins in the fetus, progresses through infancy and accelerates...... summarize current knowledge on the development of the classical endocrinological and histological features of 47,XXY males from fetus to adulthood and review the literature concerning the degeneration of the seminiferous tubules in this syndrome....

  5. Degenerate Fermi gas in a combined harmonic-lattice potential

    International Nuclear Information System (INIS)

    Blakie, P. B.; Bezett, A.; Buonsante, P.

    2007-01-01

    In this paper we derive an analytic approximation to the density of states for atoms in a combined optical lattice and harmonic trap potential as used in current experiments with quantum degenerate gases. We compare this analytic density of states to numerical solutions and demonstrate its validity regime. Our work explicitly considers the role of higher bands and when they are important in quantitative analysis of this system. Applying our density of states to a degenerate Fermi gas, we consider how adiabatic loading from a harmonic trap into the combined harmonic-lattice potential affects the degeneracy temperature. Our results suggest that occupation of excited bands during loading should lead to more favorable conditions for realizing degenerate Fermi gases in optical lattices

  6. Peripheral retinal degenerations and the risk of retinal detachment.

    Science.gov (United States)

    Lewis, Hilel

    2003-07-01

    To review the degenerative diseases of the peripheral retina in relationship with the risk to develop a rhegmatogenous retinal detachment and to present recommendations for use in eyes at increased risk of developing a retinal detachment. Focused literature review and author's clinical experience. Retinal degenerations are common lesions involving the peripheral retina, and most of them are clinically insignificant. Lattice degeneration, degenerative retinoschisis, cystic retinal tufts, and, rarely, zonular traction tufts, can result in a rhegmatogenous retinal detachment. Therefore, these lesions have been considered for prophylactic therapy; however, adequate studies have not been performed to date. Well-designed, prospective, randomized clinical studies are necessary to determine the benefit-risk ratio of prophylactic treatment. In the meantime, the evidence available suggests that most of the peripheral retinal degenerations should not be treated except in rare, high-risk situations.

  7. Methods of evaluating segmentation characteristics and segmentation of major faults

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kie Hwa; Chang, Tae Woo; Kyung, Jai Bok [Seoul National Univ., Seoul (Korea, Republic of)] (and others)

    2000-03-15

    Seismological, geological, and geophysical studies were made for reasonable segmentation of the Ulsan fault and the results are as follows. One- and two- dimensional electrical surveys revealed clearly the fault fracture zone enlarges systematically northward and southward from the vicinity of Mohwa-ri, indicating Mohwa-ri is at the seismic segment boundary. Field Geological survey and microscope observation of fault gouge indicates that the Quaternary faults in the area are reactivated products of the preexisting faults. Trench survey of the Chonbuk fault Galgok-ri revealed thrust faults and cumulative vertical displacement due to faulting during the late Quaternary with about 1.1-1.9 m displacement per event; the latest event occurred from 14000 to 25000 yrs. BP. The seismic survey showed the basement surface os cut by numerous reverse faults and indicated the possibility that the boundary between Kyeongsangbukdo and Kyeongsannamdo may be segment boundary.

  8. Segmentation by Large Scale Hypothesis Testing - Segmentation as Outlier Detection

    DEFF Research Database (Denmark)

    Darkner, Sune; Dahl, Anders Lindbjerg; Larsen, Rasmus

    2010-01-01

    a microscope and we show how the method can handle transparent particles with significant glare point. The method generalizes to other problems. THis is illustrated by applying the method to camera calibration images and MRI of the midsagittal plane for gray and white matter separation and segmentation......We propose a novel and efficient way of performing local image segmentation. For many applications a threshold of pixel intensities is sufficient but determine the appropriate threshold value can be difficult. In cases with large global intensity variation the threshold value has to be adapted...... locally. We propose a method based on large scale hypothesis testing with a consistent method for selecting an appropriate threshold for the given data. By estimating the background distribution we characterize the segment of interest as a set of outliers with a certain probability based on the estimated...

  9. Methods of evaluating segmentation characteristics and segmentation of major faults

    International Nuclear Information System (INIS)

    Lee, Kie Hwa; Chang, Tae Woo; Kyung, Jai Bok

    2000-03-01

    Seismological, geological, and geophysical studies were made for reasonable segmentation of the Ulsan fault and the results are as follows. One- and two- dimensional electrical surveys revealed clearly the fault fracture zone enlarges systematically northward and southward from the vicinity of Mohwa-ri, indicating Mohwa-ri is at the seismic segment boundary. Field Geological survey and microscope observation of fault gouge indicates that the Quaternary faults in the area are reactivated products of the preexisting faults. Trench survey of the Chonbuk fault Galgok-ri revealed thrust faults and cumulative vertical displacement due to faulting during the late Quaternary with about 1.1-1.9 m displacement per event; the latest event occurred from 14000 to 25000 yrs. BP. The seismic survey showed the basement surface os cut by numerous reverse faults and indicated the possibility that the boundary between Kyeongsangbukdo and Kyeongsannamdo may be segment boundary

  10. Orthonectids Are Highly Degenerate Annelid Worms.

    Science.gov (United States)

    Schiffer, Philipp H; Robertson, Helen E; Telford, Maximilian J

    2018-05-24

    The animal groups of Orthonectida and Dicyemida are tiny, extremely simple, vermiform endoparasites of various marine animals and have been linked in the Mesozoa (Figure 1). The Orthonectida (Figures 1A and 1B) have a few hundred cells, including a nervous system of just ten cells [2], and the Dicyemida (Figure 1C) are even simpler, with ∼40 cells [3]. They are classic "Problematica" [4]-the name Mesozoa suggests an evolutionary position intermediate between Protozoa and Metazoa (animals) [5] and implies that their simplicity is a primitive state, but molecular data have shown they are members of Lophotrochozoa within Bilateria [6-9], which means that they derive from a more complex ancestor. Their precise affinities remain uncertain, however, and it is disputed whether they even constitute a clade. Ascertaining their affinities is complicated by the very fast evolution observed in their genes, potentially leading to the common systematic error of long-branch attraction (LBA) [10]. Here, we use mitochondrial and nuclear gene sequence data and show that both dicyemids and orthonectids are members of the Lophotrochozoa. Carefully addressing the effects of unequal rates of evolution, we show that the Mesozoa is polyphyletic. While the precise position of dicyemids remains unresolved within Lophotrochozoa, we identify orthonectids as members of the phylum Annelida. This result reveals one of the most extreme cases of body-plan simplification in the animal kingdom; our finding makes sense of an annelid-like cuticle in orthonectids [2] and suggests that the circular muscle cells repeated along their body [11] may be segmental in origin. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Rapid glutamate receptor 2 trafficking during retinal degeneration

    Directory of Open Access Journals (Sweden)

    Lin Yanhua

    2012-02-01

    Full Text Available Abstract Background Retinal degenerations, such as age-related macular degeneration (AMD and retinitis pigmentosa (RP, are characterized by photoreceptor loss and anomalous remodeling of the surviving retina that corrupts visual processing and poses a barrier to late-stage therapeutic interventions in particular. However, the molecular events associated with retinal remodeling remain largely unknown. Given our prior evidence of ionotropic glutamate receptor (iGluR reprogramming in retinal degenerations, we hypothesized that the edited glutamate receptor 2 (GluR2 subunit and its trafficking may be modulated in retinal degenerations. Results Adult albino Balb/C mice were exposed to intense light for 24 h to induce light-induced retinal degeneration (LIRD. We found that prior to the onset of photoreceptor loss, protein levels of GluR2 and related trafficking proteins, including glutamate receptor-interacting protein 1 (GRIP1 and postsynaptic density protein 95 (PSD-95, were rapidly increased. LIRD triggered neuritogenesis in photoreceptor survival regions, where GluR2 and its trafficking proteins were expressed in the anomalous dendrites. Immunoprecipitation analysis showed interaction between KIF3A and GRIP1 as well as PSD-95, suggesting that KIF3A may mediate transport of GluR2 and its trafficking proteins to the novel dendrites. However, in areas of photoreceptor loss, GluR2 along with its trafficking proteins nearly vanished in retracted retinal neurites. Conclusions All together, LIRD rapidly triggers GluR2 plasticity, which is a potential mechanism behind functionally phenotypic revisions of retinal neurons and neuritogenesis during retinal degenerations.

  12. [Myopia: frequency of lattice degeneration and axial length].

    Science.gov (United States)

    Martín Sánchez, M D; Roldán Pallarés, M

    2001-05-01

    To evaluate the relationship between lattice retinal degeneration and axial length of the eye in different grades of myopia. A sample of 200 eyes from 124 myopic patients was collected by chance. The average age was 34.8 years (20-50 years) and the myopia was between 0.5 and 20 diopters (D). The eyes were grouped according to the degree of refraction defect, the mean axial length of each group (Scan A) and the frequency of lattice retinal degeneration and the relationship between these variables was studied. The possible influence of age on our results was also considered. For the statistical analysis, the SAS 6.07 program with the variance analysis for quantitative variables, and chi(2) test for qualitative variables with a 5% significance were used. A multivariable linear regression model was also adjusted. The highest frequency of lattice retinal degeneration occurred in those myopia patients having more than 15 D, and also in the group of myopia patients between 3 and 6 D, but this did not show statistical significance when compared with the other myopic groups. If the axial length is assessed, a greater frequency of lattice retinal degeneration is also found when the axial length is 25-27 mm and 29-30 mm, which correspond, respectively, to myopias between 3-10 D and more than 15 D. When the multivariable linear regression model was adjusted, the axial length showed the existence of lattice retinal degeneration (beta 0.41 mm; p=0.08) adjusted by the number of diopters (beta 0.38 mm; plattice retinal degeneration was found for myopias with axial eye length between 29-30 mm (more than 15 D), and 25-27 mm (between 3-10 D).

  13. Automatic segmentation of psoriasis lesions

    Science.gov (United States)

    Ning, Yang; Shi, Chenbo; Wang, Li; Shu, Chang

    2014-10-01

    The automatic segmentation of psoriatic lesions is widely researched these years. It is an important step in Computer-aid methods of calculating PASI for estimation of lesions. Currently those algorithms can only handle single erythema or only deal with scaling segmentation. In practice, scaling and erythema are often mixed together. In order to get the segmentation of lesions area - this paper proposes an algorithm based on Random forests with color and texture features. The algorithm has three steps. The first step, the polarized light is applied based on the skin's Tyndall-effect in the imaging to eliminate the reflection and Lab color space are used for fitting the human perception. The second step, sliding window and its sub windows are used to get textural feature and color feature. In this step, a feature of image roughness has been defined, so that scaling can be easily separated from normal skin. In the end, Random forests will be used to ensure the generalization ability of the algorithm. This algorithm can give reliable segmentation results even the image has different lighting conditions, skin types. In the data set offered by Union Hospital, more than 90% images can be segmented accurately.

  14. Extended Hellmann-Feynman theorem for degenerate eigenstates

    Science.gov (United States)

    Zhang, G. P.; George, Thomas F.

    2004-04-01

    In a previous paper, we reported a failure of the traditional Hellmann-Feynman theorem (HFT) for degenerate eigenstates. This has generated enormous interest among different groups. In four independent papers by Fernandez, by Balawender, Hola, and March, by Vatsya, and by Alon and Cederbaum, an elegant method to solve the problem was devised. The main idea is that one has to construct and diagonalize the force matrix for the degenerate case, and only the eigenforces are well defined. We believe this is an important extension to HFT. Using our previous example for an energy level of fivefold degeneracy, we find that those eigenforces correctly reflect the symmetry of the molecule.

  15. Global Carleman estimates for degenerate parabolic operators with applications

    CERN Document Server

    Cannarsa, P; Vancostenoble, J

    2016-01-01

    Degenerate parabolic operators have received increasing attention in recent years because they are associated with both important theoretical analysis, such as stochastic diffusion processes, and interesting applications to engineering, physics, biology, and economics. This manuscript has been conceived to introduce the reader to global Carleman estimates for a class of parabolic operators which may degenerate at the boundary of the space domain, in the normal direction to the boundary. Such a kind of degeneracy is relevant to study the invariance of a domain with respect to a given stochastic diffusion flow, and appears naturally in climatology models.

  16. Design of the Advanced Virgo non-degenerate recycling cavities

    International Nuclear Information System (INIS)

    Granata, M; Barsuglia, M; Flaminio, R; Freise, A; Hild, S; Marque, J

    2010-01-01

    Advanced Virgo is the project to upgrade the interferometric gravitational wave detector Virgo, and it foresees the implementation of power and signal non-degenerate recycling cavities. Such cavities suppress the build-up of high order modes of the resonating sidebands, with some advantage for the commissioning of the detector and the build-up of the gravitational signal. Here we present the baseline design of the Advanced Virgo non-degenerate recycling cavities, giving some preliminary results of simulations about the tolerances of this design to astigmatism, mirror figure errors and thermal lensing.

  17. Transport in partially degenerate, magnetized plasmas. Pt. 1. Collision operators

    International Nuclear Information System (INIS)

    Brown, S.R.; Haines, M.G.

    1997-01-01

    The quantum Boltzmann collision operator is expanded to yield a degenerate form of the Fokker-Planck collision operator. This is analyzed using Rosenbluth potentials to give a degenerate analogue of the Shkarofsky operator. The distribution function is then expanded about an equilibrium Fermi-Dirac distribution function using a tensor perturbation formulation to give a zeroth-order and a first-order collision operator. These equations are shown to satisfy the relevant conservation equations. It is shown that the distribution function relaxes to a Fermi-Dirac form through electron-electron collisions. (Author)

  18. Wallerian degeneration of the corticospinal tract in the brain stem

    International Nuclear Information System (INIS)

    Uchino, Akira; Onomura, Kentaro; Ohno, Masato

    1989-01-01

    Magnetic resonance imaging (MRI) of wallerian degeneration of the corticospinal tract in the brain stem was studied in 25 patients with chronic supratentorial vascular accidents. In the relatively early stages, at least three months after ictus, increased signal intensities in axial T 2 -weighted images - with or without decreased signal intensities in axial T 1 -weighted images - were observed in the brain stem ipsilaterally. In later stages, at least six months after ictus, shrinkage of the brain stem ipsilaterally - with or without decreased signal intensities - was clearly observed in axial T 1 -weighted images. MRI is therefore regarded a sensitive diagnostic modality for evaluating wallerian degeneration in the brain stem. (author)

  19. Relationship between retinal lattice degeneration and open angle glaucoma.

    Science.gov (United States)

    Rahimi, Mansour

    2005-01-01

    Patients with retinal disorders may develop glaucoma of both a primary and secondary type. Pigment may contribute to trabecular obstruction in some patients with open-angle glaucoma. Lattice degeneration of the retina in its typical form is a sharply demarcated, circumferentially oriented, degenerative process with significant alterations of retinal pigmentation. The association between myopia, open angle glaucoma and pigment dispersion is striking. Therefore, it could be postulated that there is significant prevalence of open angle glaucoma in patients with retinal lattice degeneration, especially in combination with myopia.

  20. Automated imaging dark adaptometer for investigating hereditary retinal degenerations

    Science.gov (United States)

    Azevedo, Dario F. G.; Cideciyan, Artur V.; Regunath, Gopalakrishnan; Jacobson, Samuel G.

    1995-05-01

    We designed and built an automated imaging dark adaptometer (AIDA) to increase accuracy, reliability, versatility and speed of dark adaptation testing in patients with hereditary retinal degenerations. AIDA increases test accuracy by imaging the ocular fundus for precise positioning of bleaching and stimulus lights. It improves test reliability by permitting continuous monitoring of patient fixation. Software control of stimulus presentation provides broad testing versatility without sacrificing speed. AIDA promises to facilitate the measurement of dark adaptation in studies of the pathophysiology of retinal degenerations and in future treatment trials of these diseases.

  1. Maximum principles for boundary-degenerate linear parabolic differential operators

    OpenAIRE

    Feehan, Paul M. N.

    2013-01-01

    We develop weak and strong maximum principles for boundary-degenerate, linear, parabolic, second-order partial differential operators, $Lu := -u_t-\\tr(aD^2u)-\\langle b, Du\\rangle + cu$, with \\emph{partial} Dirichlet boundary conditions. The coefficient, $a(t,x)$, is assumed to vanish along a non-empty open subset, $\\mydirac_0!\\sQ$, called the \\emph{degenerate boundary portion}, of the parabolic boundary, $\\mydirac!\\sQ$, of the domain $\\sQ\\subset\\RR^{d+1}$, while $a(t,x)$ may be non-zero at po...

  2. Skip segment Hirschsprung disease and Waardenburg syndrome

    Directory of Open Access Journals (Sweden)

    Erica R. Gross

    2015-04-01

    Full Text Available Skip segment Hirschsprung disease describes a segment of ganglionated bowel between two segments of aganglionated bowel. It is a rare phenomenon that is difficult to diagnose. We describe a recent case of skip segment Hirschsprung disease in a neonate with a family history of Waardenburg syndrome and the genetic profile that was identified.

  3. U.S. Army Custom Segmentation System

    Science.gov (United States)

    2007-06-01

    segmentation is individual or intergroup differences in response to marketing - mix variables. Presumptions about segments: •different demands in a...product or service category, •respond differently to changes in the marketing mix Criteria for segments: •The segments must exist in the environment

  4. Skip segment Hirschsprung disease and Waardenburg syndrome

    OpenAIRE

    Gross, Erica R.; Geddes, Gabrielle C.; McCarrier, Julie A.; Jarzembowski, Jason A.; Arca, Marjorie J.

    2015-01-01

    Skip segment Hirschsprung disease describes a segment of ganglionated bowel between two segments of aganglionated bowel. It is a rare phenomenon that is difficult to diagnose. We describe a recent case of skip segment Hirschsprung disease in a neonate with a family history of Waardenburg syndrome and the genetic profile that was identified.

  5. UNITED STATES DEPARTMENT OF TRANSPORTATION GLOBAL POSITIONING SYSTEM (GPS) ADJACENT BAND COMPATIBILITY ASSESSMENT

    Science.gov (United States)

    2018-04-01

    The goal of the U.S. Department of Transportation (DOT) Global Positioning System (GPS) Adjacent Band Compatibility Assessment is to evaluate the maximum transmitted power levels of adjacent band radiofrequency (RF) systems that can be tolerated by G...

  6. A Novel Iris Segmentation Scheme

    Directory of Open Access Journals (Sweden)

    Chen-Chung Liu

    2014-01-01

    Full Text Available One of the key steps in the iris recognition system is the accurate iris segmentation from its surrounding noises including pupil, sclera, eyelashes, and eyebrows of a captured eye-image. This paper presents a novel iris segmentation scheme which utilizes the orientation matching transform to outline the outer and inner iris boundaries initially. It then employs Delogne-Kåsa circle fitting (instead of the traditional Hough transform to further eliminate the outlier points to extract a more precise iris area from an eye-image. In the extracted iris region, the proposed scheme further utilizes the differences in the intensity and positional characteristics of the iris, eyelid, and eyelashes to detect and delete these noises. The scheme is then applied on iris image database, UBIRIS.v1. The experimental results show that the presented scheme provides a more effective and efficient iris segmentation than other conventional methods.

  7. ''Dural tail'' adjacent to a giant posterior cerebral artery aneurysm: case report and review of the literature

    International Nuclear Information System (INIS)

    Good, C.D.; Kingsley, D.P.E.; Taylor, W.J.; Harkness, W.F.

    1997-01-01

    The ''dural tail'' sign on gadolinium (Gd-DTPA)-enhanced MRI has been described in association with meningiomas. Various series with histopathological correlation have shown that in some cases there is tumour invasion into the dura mater, but in the majority of cases it represents a hypervascular, non-neoplastic reaction. While this sign was originally thought to be specific for meningioma, subsequent case reports have described the presence of a dural tail in other intra- and extra-axial lesions. We present a patient with a giant aneurysm arising from the P2 segment of the right posterior cerebral artery, adjacent to the tentorium, with a prominent dural tail on Gd-DTPA-enhanced MRI. In this location, differentiation of an aneurysm from a meningioma was critical. (orig.). With 2 figs

  8. Segment polarity gene expression in a myriapod reveals conserved and diverged aspects of early head patterning in arthropods.

    Science.gov (United States)

    Janssen, Ralf

    2012-09-01

    Arthropods show two kinds of developmental mode. In the so-called long germ developmental mode (as exemplified by the fly Drosophila), all segments are formed almost simultaneously from a preexisting field of cells. In contrast, in the so-called short germ developmental mode (as exemplified by the vast majority of arthropods), only the anterior segments are patterned similarly as in Drosophila, and posterior segments are added in a single or double segmental periodicity from a posterior segment addition zone (SAZ). The addition of segments from the SAZ is controlled by dynamic waves of gene activity. Recent studies on a spider have revealed that a similar dynamic process, involving expression of the segment polarity gene (SPG) hedgehog (hh), is involved in the formation of the anterior head segments. The present study shows that in the myriapod Glomeris marginata the early expression of hh is also in a broad anterior domain, but this domain corresponds only to the ocular and antennal segment. It does not, like in spiders, represent expression in the posterior adjacent segment. In contrast, the anterior hh pattern is conserved in Glomeris and insects. All investigated myriapod SPGs and associated factors are expressed with delay in the premandibular (tritocerebral) segment. This delay is exclusively found in insects and myriapods, but not in chelicerates, crustaceans and onychophorans. Therefore, it may represent a synapomorphy uniting insects and myriapods (Atelocerata hypothesis), contradicting the leading opinion that suggests a sister relationship of crustaceans and insects (Pancrustacea hypothesis). In Glomeris embryos, the SPG engrailed is first expressed in the mandibular segment. This feature is conserved in representatives of all arthropod classes suggesting that the mandibular segment may have a special function in anterior patterning.

  9. Document segmentation via oblique cuts

    Science.gov (United States)

    Svendsen, Jeremy; Branzan-Albu, Alexandra

    2013-01-01

    This paper presents a novel solution for the layout segmentation of graphical elements in Business Intelligence documents. We propose a generalization of the recursive X-Y cut algorithm, which allows for cutting along arbitrary oblique directions. An intermediate processing step consisting of line and solid region removal is also necessary due to presence of decorative elements. The output of the proposed segmentation is a hierarchical structure which allows for the identification of primitives in pie and bar charts. The algorithm was tested on a database composed of charts from business documents. Results are very promising.

  10. Optimally segmented permanent magnet structures

    DEFF Research Database (Denmark)

    Insinga, Andrea Roberto; Bjørk, Rasmus; Smith, Anders

    2016-01-01

    We present an optimization approach which can be employed to calculate the globally optimal segmentation of a two-dimensional magnetic system into uniformly magnetized pieces. For each segment the algorithm calculates the optimal shape and the optimal direction of the remanent flux density vector......, with respect to a linear objective functional. We illustrate the approach with results for magnet design problems from different areas, such as a permanent magnet electric motor, a beam focusing quadrupole magnet for particle accelerators and a rotary device for magnetic refrigeration....

  11. An αII Spectrin-Based Cytoskeleton Protects Large-Diameter Myelinated Axons from Degeneration.

    Science.gov (United States)

    Huang, Claire Yu-Mei; Zhang, Chuansheng; Zollinger, Daniel R; Leterrier, Christophe; Rasband, Matthew N

    2017-11-22

    Axons must withstand mechanical forces, including tension, torsion, and compression. Spectrins and actin form a periodic cytoskeleton proposed to protect axons against these forces. However, because spectrins also participate in assembly of axon initial segments (AISs) and nodes of Ranvier, it is difficult to uncouple their roles in maintaining axon integrity from their functions at AIS and nodes. To overcome this problem and to determine the importance of spectrin cytoskeletons for axon integrity, we generated mice with αII spectrin-deficient peripheral sensory neurons. The axons of these neurons are very long and exposed to the mechanical forces associated with limb movement; most lack an AIS, and some are unmyelinated and have no nodes. We analyzed αII spectrin-deficient mice of both sexes and found that, in myelinated axons, αII spectrin forms a periodic cytoskeleton with βIV and βII spectrin at nodes of Ranvier and paranodes, respectively, but that loss of αII spectrin disrupts this organization. Avil-cre;Sptan1 f/f mice have reduced numbers of nodes, disrupted paranodal junctions, and mislocalized Kv1 K + channels. We show that the density of nodal βIV spectrin is constant among axons, but the density of nodal αII spectrin increases with axon diameter. Remarkably, Avil-cre;Sptan1 f/f mice have intact nociception and small-diameter axons, but severe ataxia due to preferential degeneration of large-diameter myelinated axons. Our results suggest that nodal αII spectrin helps resist the mechanical forces experienced by large-diameter axons, and that αII spectrin-dependent cytoskeletons are also required for assembly of nodes of Ranvier. SIGNIFICANCE STATEMENT A periodic axonal cytoskeleton consisting of actin and spectrin has been proposed to help axons resist the mechanical forces to which they are exposed (e.g., compression, torsion, and stretch). However, until now, no vertebrate animal model has tested the requirement of the spectrin cytoskeleton in

  12. ASSOCIATION OF DRUSEN VOLUME WITH CHOROIDAL PARAMETERS IN NONNEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

    Science.gov (United States)

    Balasubramanian, Siva; Lei, Jianqin; Nittala, Muneeswar G; Velaga, Swetha B; Haines, Jonathan; Pericak-Vance, Margaret A; Stambolian, Dwight; Sadda, SriniVas R

    2017-10-01

    The choroid is thought to be relevant to the pathogenesis of nonneovascular age-related macular degeneration, but its role has not yet been fully defined. In this study, we evaluate the relationship between the extent of macular drusen and specific choroidal parameters, including thickness and intensity. Spectral domain optical coherence tomography images were collected from two distinct, independent cohorts with nonneovascular age-related macular degeneration: Amish (53 eyes of 34 subjects) and non-Amish (40 eyes from 26 subjects). All spectral domain optical coherence tomography scans were obtained using the Cirrus HD-OCT with a 512 × 128 macular cube (6 × 6 mm) protocol. The Cirrus advanced retinal pigment epithelium analysis tool was used to automatically compute drusen volume within 3 mm (DV3) and 5 mm (DV5) circles centered on the fovea. The inner and outer borders of the choroid were manually segmented, and the mean choroidal thickness and choroidal intensity (i.e., brightness) were calculated. The choroidal intensity was normalized against the vitreous and nerve fiber layer reflectivity. The correlation between DV and these choroidal parameters was assessed using Pearson and linear regression analysis. A significant positive correlation was observed between normalized choroidal intensity and DV5 in the Amish (r = 0.42, P = 0.002) and non-Amish (r = 0.33, P = 0.03) cohorts. Also, DV3 showed a significant positive correlation with normalized choroidal intensity in both the groups (Amish: r = 0.30, P = 0.02; non-Amish: r = 0.32, P = 0.04). Choroidal thickness was negatively correlated with normalized choroidal intensity in both Amish (r = -0.71, P = 0.001) and non-Amish (r = -0.43, P = 0.01) groups. Normalized choroidal intensity was the most significant constant predictor of DV in both the Amish and non-Amish groups. Choroidal intensity, but not choroidal thickness, seems to be associated with drusen volume in Amish and non-Amish populations. These

  13. Tritium in the Savannah River Estuary and adjacent marine waters

    International Nuclear Information System (INIS)

    Hayes, D.W.

    1978-01-01

    The tritium distribution in the Savannah River estuary and adjacent marine waters was measured to provide information on the dilution, mixing, and movement of Savannah River water in this region. The Savannah River marine region was chosen because the average tritium concentration in this river is 5 pCi/ml, whereas other rivers in the southeastern United States average less than 0.5 pCi/ml. The increased tritium concentration in the Savannah River is due to releases from the Savannah River Plant of the Department of Energy. Tritium measurements have proved particularly effective in estimating the flushing time of the Savannah River estuary (2.4 days) and in delineating the relative contribution to the water masses in Ossabaw and Port Royal Sounds from the River and from sea water. Ossabaw and Port Royal Sounds are located approximately 20 km south and north of the Savannah River estuary, respectively

  14. Tritium in the Savannah River estuary and adjacent marine waters

    International Nuclear Information System (INIS)

    Hayes, D.W.

    1979-01-01

    The tritium distribution in the Savannah River estuary and adjacent marine waters was measured to provide information on the dilution, mixing and movement of Savannah River water in this region. The Savannah River marine region was chosen because the average tritium concentration in this river is approximately 5 pCi/ml, whereas other rivers in the southeastern United States of America average less than 0.5 pCi/ml. The increased tritium concentration in the Savannah River is due to releases from the Savannah River Plant of the Department of Energy. Tritium measurements have proved particularly effective in estimating the flushing time of the Savannah River estuary (2.4 days) and in delineating the relative contribution to the water masses in Ossabaw and Port Royal Sounds from the river and from sea-water. Ossabaw and Port Royal Sounds are located approximately 20 km south and north of the Savannah River estuary respectively. (author)

  15. Edge scour in current adjacent to stone covers

    DEFF Research Database (Denmark)

    Petersen, Thor Ugelvig; Sumer, B. Mutlu; Meyer, Knud Erik

    The present paper reports some early results of an experimental investigation of edge scour in currents. Two kinds of measurements are made (1) Particle Image Velocimetry (PIV) measurements of secondary currents that take place near a junction between the stone cover and the sand bed in a clear......-water experiment; and (2) scour measurements in actual scour experiment in the live-bed regime. The early results indicate that edge scour in a steady current propagating in-line with a stone layer is caused by the combined action of two effects; (1) Primary flow and (2) Secondary flow. The primary flow stirs up...... the sediment and puts into suspension, and the secondary flow carries it away from the junction between the stone layer and the sand bed, resulting in a scour hole forming adjacent to the toe of the stone layer....

  16. GOAT ROCKS WILDERNESS AND ADJACENT ROADLESS AREAS, WASHINGTON.

    Science.gov (United States)

    Church, S.E.; Close, T.J.

    1984-01-01

    The Goat Rocks Wilderness and adjacent roadless areas are a rugged, highly forested, scenic area located on the crest of the Cascade Range in south-central Washington. Several mineral claims have been staked in the area. Mineral surveys were conducted. Geochemical, geophysical, and geologic investigations indicate that three areas have probable mineral-resource potential for base metals in porphyry-type deposits. Available data are not adequate to permit definition of the potential for oil and gas. There is little likelihood for the occurrence of other kinds of energy resources in the area. Evaluation of resource potential in the three areas identified as having probable mineral-resource potential could be improved by more detailed geochemical studies and geologic mapping.

  17. Intercalary bone segment transport in treatment of segmental tibial defects

    International Nuclear Information System (INIS)

    Iqbal, A.; Amin, M.S.

    2002-01-01

    Objective: To evaluate the results and complications of intercalary bone segment transport in the treatment of segmental tibial defects. Design: This is a retrospective analysis of patients with segmental tibial defects who were treated with intercalary bone segment transport method. Place and Duration of Study: The study was carried out at Combined Military Hospital, Rawalpindi from September 1997 to April 2001. Subjects and methods: Thirteen patients were included in the study who had developed tibial defects either due to open fractures with bone loss or subsequent to bone debridement of infected non unions. The mean bone defect was 6.4 cms and there were eight associated soft tissue defects. Locally made unilateral 'Naseer-Awais' (NA) fixator was used for bone segment transport. The distraction was done at the rate of 1mm/day after 7-10 days of osteotomy. The patients were followed-up fortnightly during distraction and monthly thereafter. The mean follow-up duration was 18 months. Results: The mean time in external fixation was 9.4 months. The m ean healing index' was 1.47 months/cm. Satisfactory union was achieved in all cases. Six cases (46.2%) required bone grafting at target site and in one of them grafting was required at the level of regeneration as well. All the wounds healed well with no residual infection. There was no residual leg length discrepancy of more than 20 mm nd one angular deformity of more than 5 degrees. The commonest complication encountered was pin track infection seen in 38% of Shanz Screws applied. Loosening occurred in 6.8% of Shanz screws, requiring re-adjustment. Ankle joint contracture with equinus deformity and peroneal nerve paresis occurred in one case each. The functional results were graded as 'good' in seven, 'fair' in four, and 'poor' in two patients. Overall, thirteen patients had 31 (minor/major) complications with a ratio of 2.38 complications per patient. To treat the bone defects and associated complications, a mean of

  18. 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

  19. A JOINT FRAMEWORK FOR 4D SEGMENTATION AND ESTIMATION OF SMOOTH TEMPORAL APPEARANCE CHANGES.

    Science.gov (United States)

    Gao, Yang; Prastawa, Marcel; Styner, Martin; Piven, Joseph; Gerig, Guido

    2014-04-01

    Medical imaging studies increasingly use longitudinal images of individual subjects in order to follow-up changes due to development, degeneration, disease progression or efficacy of therapeutic intervention. Repeated image data of individuals are highly correlated, and the strong causality of information over time lead to the development of procedures for joint segmentation of the series of scans, called 4D segmentation. A main aim was improved consistency of quantitative analysis, most often solved via patient-specific atlases. Challenging open problems are contrast changes and occurance of subclasses within tissue as observed in multimodal MRI of infant development, neurodegeneration and disease. This paper proposes a new 4D segmentation framework that enforces continuous dynamic changes of tissue contrast patterns over time as observed in such data. Moreover, our model includes the capability to segment different contrast patterns within a specific tissue class, for example as seen in myelinated and unmyelinated white matter regions in early brain development. Proof of concept is shown with validation on synthetic image data and with 4D segmentation of longitudinal, multimodal pediatric MRI taken at 6, 12 and 24 months of age, but the methodology is generic w.r.t. different application domains using serial imaging.

  20. Socintigraphic evaluation of lateral segment of the left lobe of the liver

    International Nuclear Information System (INIS)

    Oyama, Kazuyuki; Hayashi, Sanshin; Kogure, Takashi; Hirakawa, Ken; Akaike, Akira

    1979-01-01

    Lateral segment of left lobe of the liver is clearly demarcated on sup(99m) Tc-labeled cholescintigram. With analysis of 112 sup(99m) Tc-pyridoxylideneisoleucine scintigrams about lateral border of left lobe, there are some variants in 22 cases (19.7%) in shape in lateral segment of Type 4 left lobe in morphologic classification. Of lateral segment of left lobe, there are classified into five types in the anterior view according to the degeneration; Type 1 is gradually elongated tapered type in 8 cases (36.4%), Type 2 is laterally elongated type as rod shape or island shape in 5 cases (22.7%), Type 3 is lobulated type in 1 case (4.6%), Type 4 is narrowing type in 5 cases (22.7%), Type 5 is indentation type in 3 cases (13.6%). Using colloidal radiopharmaceuticals in liver scintigraphy, lateral segment of left lobe often overlapps with the spleen, which disturb to interpret the abnormality in left lobe of the liver and in the spleen. This analysis depends upon the recent advances in sup(99m) Tc-labeled hepatobiliary radiopharmaceuticals and equipment, and there has never discussed about the shape of lateral segment of left lobe in roentgenologic and scintigraphic evaluations. (author)

  1. Semi-automatic geographic atrophy segmentation for SD-OCT images.

    Science.gov (United States)

    Chen, Qiang; de Sisternes, Luis; Leng, Theodore; Zheng, Luoluo; Kutzscher, Lauren; Rubin, Daniel L

    2013-01-01

    Geographic atrophy (GA) is a condition that is associated with retinal thinning and loss of the retinal pigment epithelium (RPE) layer. It appears in advanced stages of non-exudative age-related macular degeneration (AMD) and can lead to vision loss. We present a semi-automated GA segmentation algorithm for spectral-domain optical coherence tomography (SD-OCT) images. The method first identifies and segments a surface between the RPE and the choroid to generate retinal projection images in which the projection region is restricted to a sub-volume of the retina where the presence of GA can be identified. Subsequently, a geometric active contour model is employed to automatically detect and segment the extent of GA in the projection images. Two image data sets, consisting on 55 SD-OCT scans from twelve eyes in eight patients with GA and 56 SD-OCT scans from 56 eyes in 56 patients with GA, respectively, were utilized to qualitatively and quantitatively evaluate the proposed GA segmentation method. Experimental results suggest that the proposed algorithm can achieve high segmentation accuracy. The mean GA overlap ratios between our proposed method and outlines drawn in the SD-OCT scans, our method and outlines drawn in the fundus auto-fluorescence (FAF) images, and the commercial software (Carl Zeiss Meditec proprietary software, Cirrus version 6.0) and outlines drawn in FAF images were 72.60%, 65.88% and 59.83%, respectively.

  2. Hydrophilic segmented block copolymers based on poly(ethylene oxide) and monodisperse amide segments

    NARCIS (Netherlands)

    Husken, D.; Feijen, Jan; Gaymans, R.J.

    2007-01-01

    Segmented block copolymers based on poly(ethylene oxide) (PEO) flexible segments and monodisperse crystallizable bisester tetra-amide segments were made via a polycondensation reaction. The molecular weight of the PEO segments varied from 600 to 4600 g/mol and a bisester tetra-amide segment (T6T6T)

  3. Sequential changes in MR imaging of human wallerian degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Orita, Tetsuji; Tsurutani, Tohru; Izumihara, Akifumi; Kajiwara, Koji (Shuto General Hospital, Yamaguchi (Japan)); Matsunaga, Tokio

    1994-05-01

    MRI of wallerian degeneration of the pyramidal tract in the brainstem was repeatedly performed on the same coronal slice in 10 patients, who had infarction or hemorrhage of the basal ganglia and had the exact onset of hemiparesis. The processes of wallerian degeneration were divided into four stages by proton-density weighted images. In stage 1, the axon began to degenerate and was destroyed. It occurred during the first 0.7 month and resulted in no signal intensity abnormality. In stage 2, axon debris disappeared from degenerating tracts. Myelin structure was preserved and myelin lipid remained intact. The lipid water ratio in the tissue became large and the tissue was more hydrophobic. From 0.7 to 2.0 months, low signal intensity was observed. In stage 3, subsequent myelin lipid breakdown began and the lipid/water ratio in the tissue tended to be small. There was no abnormal signal intensity. In stage 4, lipid began to be removed from the tissue. The lipid/water ratio became smaller and the tissue became hydrophilic. Gliosis was more prominent. High signal intensity was observed. (author).

  4. Cartilage Degeneration and Alignment in Severe Varus Knee Osteoarthritis.

    Science.gov (United States)

    Nakagawa, Yasuaki; Mukai, Shogo; Yabumoto, Hiromitsu; Tarumi, Eri; Nakamura, Takashi

    2015-10-01

    The aim of this study was to examine the relationship between cartilage, ligament, and meniscus degeneration and radiographic alignment in severe varus knee osteoarthritis in order to understand the development of varus knee osteoarthritis. Fifty-three patients (71 knees) with primary varus knee osteoarthritis and who underwent total knee arthroplasty were selected for this study. There were 6 men and 47 women, with 40 right knees and 31 left knees studied; their mean age at operation was 73.5 years. The ligament, meniscus, degeneration of joint cartilage, and radiographic alignments were examined visually. The tibial plateau-tibial shaft angle was larger if the condition of the cartilage in the lateral femoral condyle was worse. The femorotibial angle and tibial plateau-tibial shaft angle were larger if the conditions of the lateral meniscus or the cartilage in the lateral tibial plateau were worse. Based on the results of this study, progression of varus knee osteoarthritis may occur in the following manner: medial knee osteoarthritis starts in the central portion of the medial tibial plateau, and accompanied by medial meniscal extrusion and anterior cruciate ligament rupture, cartilage degeneration expands from the anterior to the posterior in the medial tibial plateau. Bone attrition occurs in the medial tibial plateau, and the femoro-tibial angle and tibial plateau-tibial shaft angle increase. Therefore, the lateral intercondylar eminence injures the cartilage of the lateral femoral condyle in the longitudinal fissure type. Thereafter, the cartilage degeneration expands in the whole of the knee joints.

  5. 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

  6. Cesare Lombroso: an anthropologist between evolution and degeneration.

    Science.gov (United States)

    Mazzarello, Paolo

    2011-01-01

    Cesare Lombroso (1835-1909) was a prominent Italian medical doctor and intellectual in the second half of the nineteenth century. He became world famous for his theory that criminality, madness and genius were all sides of the same psychobiological condition: an expression of degeneration, a sort of regression along the phylogenetic scale, and an arrest at an early stage of evolution. Degeneration affected criminals especially, in particular the "born delinquent" whose development had stopped at an early stage, making them the most "atavistic" types of human being. Lombroso also advocated the theory that genius was closely linked with madness. A man of genius was a degenerate, an example of retrograde evolution in whom madness was a form of "biological compensation" for excessive intellectual development. To confirm this theory, in August 1897, Lombroso, while attending the Twelfth International Medical Congress in Moscow, decided to meet the great Russian writer Lev Tolstoy in order to directly verify, in him, his theory of degeneration in the genius. Lombroso's anthropological ideas fuelled a heated debate on the biological determinism of human behaviour.

  7. A class of degenerate stochastic differential equations with non ...

    Indian Academy of Sciences (India)

    Introduction. In this article we consider (possibly degenerate) stochastic differential equations (SDEs) with non-Lipschitz coefficients. If the coefficients are Lipschitz, we can prove the existence of a unique strong solution (see [9]). But uniqueness fails in the case of non-Lipschitz coefficients. The literature on this topic is not ...

  8. Spectral analysis of linear relations and degenerate operator semigroups

    International Nuclear Information System (INIS)

    Baskakov, A G; Chernyshov, K I

    2002-01-01

    Several problems of the spectral theory of linear relations in Banach spaces are considered. Linear differential inclusions in a Banach space are studied. The construction of the phase space and solutions is carried out with the help of the spectral theory of linear relations, ergodic theorems, and degenerate operator semigroups

  9. Revisiting non-degenerate parametric down-conversion

    Indian Academy of Sciences (India)

    conversion process is studied by recasting the time evolution equations for the basic op- erators in an equivalent ... We consider a model of non-degenerate parametric down-conversion process com- posed of two coupled ..... e−iωat and eiωbt have been left out in writing down the final results in ref. [4], even though these ...

  10. A study of retrograde degeneration of median nerve forearm ...

    African Journals Online (AJOL)

    Introduction: Carpal tunnel syndrome (CTS) is a disorder of the hand which results from compression of the median nerve within its fibro-osseous tunnel at the wrist. The slowing in the forearm motor conduction velocity suggests the presence of retrograde degeneration. Existing studies conflict regarding a correlation ...

  11. Prevalence of Age-Related Macular Degeneration in Europe

    NARCIS (Netherlands)

    Colijn, Johanna M.; Buitendijk, Gabriëlle H. S.; Prokofyeva, Elena; Alves, Dalila; Cachulo, Maria L.; Khawaja, Anthony P.; Cougnard-Gregoire, Audrey; Merle, Bénédicte M. J.; Korb, Christina; Erke, Maja G.; Bron, Alain; Anastasopoulos, Eleftherios; Meester-Smoor, Magda A.; Segato, Tatiana; Piermarocchi, Stefano; de Jong, Paulus T. V. M.; Vingerling, Johannes R.; Topouzis, Fotis; Creuzot-Garcher, Catherine; Bertelsen, Geir; Pfeiffer, Norbert; Fletcher, Astrid E.; Foster, Paul J.; Silva, Rufino; Korobelnik, Jean-François; Delcourt, Cécile; Klaver, Caroline C. W.; Ajana, Soufiane; Arango-Gonzalez, Blanca; Arndt, Verena; Bhatia, Vaibhav; Bhattacharya, Shomi S.; Biarnés, Marc; Borrell, Anna; Bühren, Sebastian; Calado, Sofia M.; Cougnard-Grégoire, Audrey; Dammeier, Sascha; de Jong, Eiko K.; de la Cerda, Berta; den Hollander, Anneke I.; Diaz-Corrales, Francisco J.; Diether, Sigrid; Emri, Eszter; Endermann, Tanja; Ferraro, Lucia L.; Garcia, Míriam; Heesterbeek, Thomas J.; Honisch, Sabina; Bergen, Arthur

    2017-01-01

    Purpose: Age-related macular degeneration (AMD) is a frequent, complex disorder in elderly of European ancestry. Risk profiles and treatment options have changed considerably over the years, which may have affected disease prevalence and outcome. We determined the prevalence of early and late AMD in

  12. 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.

  13. The Cerebellum and Language: Evidence from Patients with Cerebellar Degeneration

    Science.gov (United States)

    Stoodley, Catherine J.; Schmahmann, Jeremy D.

    2009-01-01

    Clinical and imaging studies suggest that the cerebellum is involved in language tasks, but the extent to which slowed language production in cerebellar patients contributes to their poor performance on these tasks is not clear. We explored this relationship in 18 patients with cerebellar degeneration and 16 healthy controls who completed measures…

  14. A mouse model for degeneration of the spiral ligament.

    Science.gov (United States)

    Kada, Shinpei; Nakagawa, Takayuki; Ito, Juichi

    2009-06-01

    Previous studies have indicated the importance of the spiral ligament (SL) in the pathogenesis of sensorineural hearing loss. The aim of this study was to establish a mouse model for SL degeneration as the basis for the development of new strategies for SL regeneration. We injected 3-nitropropionic acid (3-NP), an inhibitor of succinate dehydrogenase, at various concentrations into the posterior semicircular canal of adult C57BL/6 mice. Saline-injected animals were used as controls. Auditory function was monitored by measurements of auditory brain stem responses (ABRs). On postoperative day 14, cochlear specimens were obtained after the measurement of the endocochlear potential (EP). Animals that were injected with 5 or 10 mM 3-NP showed a massive elevation of ABR thresholds along with extensive degeneration of the cochleae. Cochleae injected with 1 mM 3-NP exhibited selective degeneration of the SL fibrocytes but alterations in EP levels and ABR thresholds were not of sufficient magnitude to allow for testing functional recovery after therapeutic interventions. Animals injected with 3 mM 3-NP showed a reduction of around 50% in the EP along with a significant loss of SL fibrocytes, although degeneration of spiral ganglion neurons and hair cells was still present in certain regions. These findings indicate that cochleae injected with 3 mM 3-NP may be useful in investigations designed to test the feasibility of new therapeutic manipulations for functional SL regeneration.

  15. Nonlinear anisotropic elliptic equations with variable exponents and degenerate coercivity

    Directory of Open Access Journals (Sweden)

    Hocine Ayadi

    2018-02-01

    Full Text Available In this article, we prove the existence and the regularity of distributional solutions for a class of nonlinear anisotropic elliptic equations with $p_i(x$ growth conditions, degenerate coercivity and $L^{m(\\cdot}$ data, with $m(\\cdot$ being small, in appropriate Lebesgue-Sobolev spaces with variable exponents. The obtained results extend some existing ones [8,10].

  16. Age-related macular degeneration in Onitsha, Nigeria | Nwosu ...

    African Journals Online (AJOL)

    Objectives: To determine the incidence, pattern and ocular morbidity associated with age-related macular degeneration (AMD) at the Guinness Eye Center Onitsha Nigeria. Materials and Methods: The case files of all new patients aged 50 years and above seen between January 1997 and December 2004 were reviewed.

  17. Sequential changes in MR imaging of human wallerian degeneration

    International Nuclear Information System (INIS)

    Orita, Tetsuji; Tsurutani, Tohru; Izumihara, Akifumi; Kajiwara, Koji; Matsunaga, Tokio.

    1994-01-01

    MRI of wallerian degeneration of the pyramidal tract in the brainstem was repeatedly performed on the same coronal slice in 10 patients, who had infarction or hemorrhage of the basal ganglia and had the exact onset of hemiparesis. The processes of wallerian degeneration were divided into four stages by proton-density weighted images. In stage 1, the axon began to degenerate and was destroyed. It occurred during the first 0.7 month and resulted in no signal intensity abnormality. In stage 2, axon debris disappeared from degenerating tracts. Myelin structure was preserved and myelin lipid remained intact. The lipid water ratio in the tissue became large and the tissue was more hydrophobic. From 0.7 to 2.0 months, low signal intensity was observed. In stage 3, subsequent myelin lipid breakdown began and the lipid/water ratio in the tissue tended to be small. There was no abnormal signal intensity. In stage 4, lipid began to be removed from the tissue. The lipid/water ratio became smaller and the tissue became hydrophilic. Gliosis was more prominent. High signal intensity was observed. (author)

  18. Twisted mass lattice QCD with non-degenerate quark masses

    International Nuclear Information System (INIS)

    Muenster, Gernot; Sudmann, Tobias

    2006-01-01

    Quantum Chromodynamics on a lattice with Wilson fermions and a chirally twisted mass term is considered in the framework of chiral perturbation theory. For two and three numbers of quark flavours, respectively, with non-degenerate quark masses the pseudoscalar meson masses and decay constants are calculated in next-to-leading order including lattice effects quadratic in the lattice spacing a

  19. Treatment of dry age-related macular degeneration with dobesilate

    OpenAIRE

    Cuevas, P; Outeiriño, L A; Angulo, J; Giménez-Gallego, G

    2012-01-01

    The authors present anatomical and functional evidences of dry age-macular degeneration improvement, after intravitreal treatment with dobesilate. Main outcomes measures were normalisation of retinal structure and function, assessed by optical coherence tomography, fundus-monitored microperimetry, electrophysiology and visual acuity. The effect might be related to the normalisation of the outer retinal architecture.

  20. Urocortin 2 treatment is protective in excitotoxic retinal degeneration.

    Science.gov (United States)

    Szabadfi, K; Kiss, P; Reglodi, D; Fekete, E M; Tamas, A; Danyadi, B; Atlasz, T; Gabriel, R

    2014-03-01

    Urocortin 2 (Ucn 2) is a corticotrop releasing factor paralog peptide with many physiological functions and it has widespread distribution. There are some data on the cytoprotective effects of Ucn 2, but less is known about its neuro- and retinoprotective actions. We have previously shown that Ucn 2 is protective in ischemia-induced retinal degeneration. The aim of the present study was to examine the protective potential of Ucn 2 in monosodium-glutamate (MSG)-induced retinal degeneration by routine histology and to investigate cell-type specific effects by immunohistochemistry. Rat pups received MSG applied on postnatal days 1, 5 and 9 and Ucn 2 was injected intravitreally into one eye. Retinas were processed for histology and immunocytochemistry after 3 weeks. Immunolabeling was determined for glial fibrillary acidic protein, vesicular glutamate transporter 1, protein kinase Cα, calbindin, parvalbumin and calretinin. Retinal tissue from animals treated with MSG showed severe degeneration compared to normal retinas, but intravitreal Ucn 2 treatment resulted in a retained retinal structure both at histological and neurochemical levels: distinct inner retinal layers and rescued inner retinal cells (different types of amacrine and rod bipolar cells) could be observed. These findings support the neuroprotective function of Ucn 2 in MSG-induced retinal degeneration.

  1. Therapeutic Approaches to Histone Reprogramming in Retinal Degeneration.

    Science.gov (United States)

    Berner, Andre K; Kleinman, Mark E

    2016-01-01

    Recent data have revealed epigenetic derangements and subsequent chromatin remodeling as a potent biologic switch for chronic inflammation and cell survival which are important therapeutic targets in the pathogenesis of several retinal degenerations. Histone deacetylases (HDACs) are a major component of this system and serve as a unique control of the chromatin remodeling process. With a multitude of targeted HDAC inhibitors now available, their use in both basic science and clinical studies has widened substantially. In the field of ocular biology, there are data to suggest that HDAC inhibition may suppress neovascularization and may be a possible treatment for retinitis pigmentosa and dry age-related macular degeneration (AMD). However, the effects of these inhibitors on cell survival and chemokine expression in the chorioretinal tissues remain very unclear. Here, we review the multifaceted biology of HDAC activity and pharmacologic inhibition while offering further insight into the importance of this epigenetic pathway in retinal degenerations. Our laboratory investigations aim to open translational avenues to advance dry AMD therapeutics while exploring the role of acetylation on inflammatory gene expression in the aging and degenerating retina.

  2. Relativistic many-body XMCD theory including core degenerate effects

    Science.gov (United States)

    Fujikawa, Takashi

    2009-11-01

    A many-body relativistic theory to analyze X-ray Magnetic Circular Dichroism (XMCD) spectra has been developed on the basis of relativistic quantum electrodynamic (QED) Keldysh Green's function approach. This theoretical framework enables us to handle relativistic many-body effects in terms of correlated nonrelativistic Green's function and relativistic correction operator Q, which naturally incorporates radiation field screening and other optical field effects in addition to electron-electron interactions. The former can describe the intensity ratio of L2/L3 which deviates from the statistical weight (branching ratio) 1/2. In addition to these effects, we consider the degenerate or nearly degenerate effects of core levels from which photoelectrons are excited. In XPS spectra, for example in Rh 3d sub level excitations, their peak shapes are quite different: This interesting behavior is explained by core-hole moving after the core excitation. We discuss similar problems in X-ray absorption spectra in particular excitation from deep 2p sub levels which are degenerate in each sub levels and nearly degenerate to each other in light elements: The hole left behind is not frozen there. We derive practical multiple scattering formulas which incorporate all those effects.

  3. Gene-diet interactions in age-related macular degeneration

    Science.gov (United States)

    Age-related macular degeneration (AMD) is a prevalent blinding disease, accounting for roughly 50% of blindness in developed nations. Very significant advances have been made in terms of discovering genetic susceptibilities to AMD as well as dietary risk factors. To date, nutritional supplementation...

  4. Prevalence of Age-Related Macular Degeneration in Europe

    DEFF Research Database (Denmark)

    Colijn, Johanna M; Buitendijk, Gabriëlle H S; Prokofyeva, Elena

    2017-01-01

    PURPOSE: Age-related macular degeneration (AMD) is a frequent, complex disorder in elderly of European ancestry. Risk profiles and treatment options have changed considerably over the years, which may have affected disease prevalence and outcome. We determined the prevalence of early and late AMD...

  5. Ranibizumab vs. aflibercept for wet age-related macular degeneration

    DEFF Research Database (Denmark)

    Szabo, Shelagh M; Hedegaard, Morten; Chan, Keith

    2015-01-01

    OBJECTIVE: Although a reduced aflibercept (2.0 mg) injection frequency relative to the approved dosing posology is included in national treatment guidelines for wet age-related macular degeneration (AMD), there is limited evidence of its comparative efficacy. The objective was to compare...

  6. Awareness, Knowledge, and Concern about Age-Related Macular Degeneration

    Science.gov (United States)

    Cimarolli, Verena R.; Laban-Baker, Allie; Hamilton, Wanda S.; Stuen, Cynthia

    2012-01-01

    Age-related macular degeneration (AMD)--a common eye disease causing vision loss--can be detected early through regular eye-health examinations, and measures can be taken to prevent visual decline. Getting eye examinations requires certain levels of awareness, knowledge, and concern related to AMD. However, little is known about AMD-related…

  7. Nutritional modulation of age-related macular degeneration

    Science.gov (United States)

    Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly worldwide. It affects 30-50 million individuals and clinical hallmarks of AMD are observed in at least one third of persons over the age of 75 in industrialized countries (Gehrs et al., 2006). Costs associated wi...

  8. Identification of Age-Related Macular Degeneration Using OCT Images

    Science.gov (United States)

    Arabi, Punal M., Dr; Krishna, Nanditha; Ashwini, V.; Prathibha, H. M.

    2018-02-01

    Age-related Macular Degeneration is the most leading retinal disease in the recent years. Macular degeneration occurs when the central portion of the retina, called macula deteriorates. As the deterioration occurs with the age, it is commonly referred as Age-related Macular Degeneration. This disease can be visualized by several imaging modalities such as Fundus imaging technique, Optical Coherence Tomography (OCT) technique and many other. Optical Coherence Tomography is the widely used technique for screening the Age-related Macular Degeneration disease, because it has an ability to detect the very minute changes in the retina. The Healthy and AMD affected OCT images are classified by extracting the Retinal Pigmented Epithelium (RPE) layer of the images using the image processing technique. The extracted layer is sampled, the no. of white pixels in each of the sample is counted and the mean value of the no. of pixels is calculated. The average mean value is calculated for both the Healthy and the AMD affected images and a threshold value is fixed and a decision rule is framed to classify the images of interest. The proposed method showed an accuracy of 75%.

  9. Propofol causes neuronal degeneration in neonatal mice and long ...

    African Journals Online (AJOL)

    Propofol causes neuronal degeneration in neonatal mice and long-term ... of 2.5 and 5.0 mg/kg (treatment group) or normal saline (control) on postnatal day 7. ... PO2, glucose and lactate), among which decreased blood glucose might be ...

  10. Neuron Morphology Influences Axon Initial Segment Plasticity.

    Science.gov (United States)

    Gulledge, Allan T; Bravo, Jaime J

    2016-01-01

    In most vertebrate neurons, action potentials are initiated in the axon initial segment (AIS), a specialized region of the axon containing a high density of voltage-gated sodium and potassium channels. It has recently been proposed that neurons use plasticity of AIS length and/or location to regulate their intrinsic excitability. Here we quantify the impact of neuron morphology on AIS plasticity using computational models of simplified and realistic somatodendritic morphologies. In small neurons (e.g., dentate granule neurons), excitability was highest when the AIS was of intermediate length and located adjacent to the soma. Conversely, neurons having larger dendritic trees (e.g., pyramidal neurons) were most excitable when the AIS was longer and/or located away from the soma. For any given somatodendritic morphology, increasing dendritic membrane capacitance and/or conductance favored a longer and more distally located AIS. Overall, changes to AIS length, with corresponding changes in total sodium conductance, were far more effective in regulating neuron excitability than were changes in AIS location, while dendritic capacitance had a larger impact on AIS performance than did dendritic conductance. The somatodendritic influence on AIS performance reflects modest soma-to-AIS voltage attenuation combined with neuron size-dependent changes in AIS input resistance, effective membrane time constant, and isolation from somatodendritic capacitance. We conclude that the impact of AIS plasticity on neuron excitability will depend largely on somatodendritic morphology, and that, in some neurons, a shorter or more distally located AIS may promote, rather than limit, action potential generation.

  11. Degree of tendon degeneration and stage of rotator cuff disease.

    Science.gov (United States)

    Jo, Chris Hyunchul; Shin, Won Hyoung; Park, Ji Wan; Shin, Ji Sun; Kim, Ji Eun

    2017-07-01

    While tendon degeneration has been known to be an important cause of rotator cuff disease, few studies have objectively proven the association of tendon degeneration and rotator cuff disease. The purpose of this study was to investigate changes of tendon degeneration with respect to the stage of rotator cuff disease. A total of 48 patients were included in the study: 12 with tendinopathy, 12 with a partial-thickness tear (pRCT), 12 with a full-thickness tear (fRCT), and 12 as the control. A full-thickness supraspinatus tendon sample was harvested en bloc from the middle portion between the lateral edge and the musculotendinous junction of the tendon using a biopsy punch with a diameter of 3 mm. Harvested samples were evaluated using a semi-quantitative grading scale with 7 parameters after haematoxylin and eosin staining. There was no significant difference in age, gender, symptom duration, and Kellgren-Lawrence grade between the groups except for the global fatty degeneration index. All of the seven parameters were significantly different between the groups and could be categorized as follows: early responders (fibre structure and arrangement), gradual responder (rounding of the nuclei), after-tear responders (cellularity, vascularity, and stainability), and late responder (hyalinization). The total degeneration scores were not significantly different between the control (6.08 ± 1.16) and tendinopathy (6.67 ± 1.83) (n.s.). However, the score of pRCT group (10.42 ± 1.31) was greater than that of tendinopathy (P rotator cuff disease progresses from tendinopathy to pRCT, and then to fRCT. The degree of degeneration of tendinopathy was not different from that of normal but aged tendons, and significant tendon degeneration began from the stage of pRCT. The clinical relevance of the study is that strategies and goals of the treatment for rotator cuff disease should be specific to its stage, in order to prevent disease progression for tendinopathy and pRCT, as

  12. Gender difference in genetic association between IL1A variant and early lumbar disc degeneration

    DEFF Research Database (Denmark)

    Eskola, Pasi J; Kjær, Per; Sorensen, Joan S

    2012-01-01

    The purpose of the present study was to analyze the associations between specific genetic markers and early disc degeneration (DD) or early disc degeneration progression (DDP) defined by magnetic resonance imaging (MRI)....

  13. Three Studies Point to Same Risk Gene for Age-Related Macular Degeneration

    Science.gov (United States)

    ... point to same risk gene for age-related macular degeneration NIH-funded research helps unravel the biology of ... rare, but powerful risk factor for age-related macular degeneration (AMD), a common cause of vision loss in ...

  14. Plantar fascia segmentation and thickness estimation in ultrasound images.

    Science.gov (United States)

    Boussouar, Abdelhafid; Meziane, Farid; Crofts, Gillian

    2017-03-01

    Ultrasound (US) imaging offers significant potential in diagnosis of plantar fascia (PF) injury and monitoring treatment. In particular US imaging has been shown to be reliable in foot and ankle assessment and offers a real-time effective imaging technique that is able to reliably confirm structural changes, such as thickening, and identify changes in the internal echo structure associated with diseased or damaged tissue. Despite the advantages of US imaging, images are difficult to interpret during medical assessment. This is partly due to the size and position of the PF in relation to the adjacent tissues. It is therefore a requirement to devise a system that allows better and easier interpretation of PF ultrasound images during diagnosis. This study proposes an automatic segmentation approach which for the first time extracts ultrasound data to estimate size across three sections of the PF (rearfoot, midfoot and forefoot). This segmentation method uses artificial neural network module (ANN) in order to classify small overlapping patches as belonging or not-belonging to the region of interest (ROI) of the PF tissue. Features ranking and selection techniques were performed as a post-processing step for features extraction to reduce the dimension and number of the extracted features. The trained ANN classifies the image overlapping patches into PF and non-PF tissue, and then it is used to segment the desired PF region. The PF thickness was calculated using two different methods: distance transformation and area-length calculation algorithms. This new approach is capable of accurately segmenting the PF region, differentiating it from surrounding tissues and estimating its thickness. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. An Accurate liver segmentation method using parallel computing algorithm

    International Nuclear Information System (INIS)

    Elbasher, Eiman Mohammed Khalied

    2014-12-01

    Computed Tomography (CT or CAT scan) is a noninvasive diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones muscles, fat and organs CT scans are more detailed than standard x-rays. CT scans may be done with or without "contrast Contrast refers to a substance taken by mouth and/ or injected into an intravenous (IV) line that causes the particular organ or tissue under study to be seen more clearly. CT scan of the liver and biliary tract are used in the diagnosis of many diseases in the abdomen structures, particularly when another type of examination, such as X-rays, physical examination, and ultra sound is not conclusive. Unfortunately, the presence of noise and artifact in the edges and fine details in the CT images limit the contrast resolution and make diagnostic procedure more difficult. This experimental study was conducted at the College of Medical Radiological Science, Sudan University of Science and Technology and Fidel Specialist Hospital. The sample of study was included 50 patients. The main objective of this research was to study an accurate liver segmentation method using a parallel computing algorithm, and to segment liver and adjacent organs using image processing technique. The main technique of segmentation used in this study was watershed transform. The scope of image processing and analysis applied to medical application is to improve the quality of the acquired image and extract quantitative information from medical image data in an efficient and accurate way. The results of this technique agreed wit the results of Jarritt et al, (2010), Kratchwil et al, (2010), Jover et al, (2011), Yomamoto et al, (1996), Cai et al (1999), Saudha and Jayashree (2010) who used different segmentation filtering based on the methods of enhancing the computed tomography images. Anther

  16. Dictionary Based Segmentation in Volumes

    DEFF Research Database (Denmark)

    Emerson, Monica Jane; Jespersen, Kristine Munk; Jørgensen, Peter Stanley

    Method for supervised segmentation of volumetric data. The method is trained from manual annotations, and these annotations make the method very flexible, which we demonstrate in our experiments. Our method infers label information locally by matching the pattern in a neighborhood around a voxel ...... to a dictionary, and hereby accounts for the volume texture....

  17. Multiple Segmentation of Image Stacks

    DEFF Research Database (Denmark)

    Smets, Jonathan; Jaeger, Manfred

    2014-01-01

    We propose a method for the simultaneous construction of multiple image segmentations by combining a recently proposed “convolution of mixtures of Gaussians” model with a multi-layer hidden Markov random field structure. The resulting method constructs for a single image several, alternative...

  18. Segmenting Trajectories by Movement States

    NARCIS (Netherlands)

    Buchin, M.; Kruckenberg, H.; Kölzsch, A.; Timpf, S.; Laube, P.

    2013-01-01

    Dividing movement trajectories according to different movement states of animals has become a challenge in movement ecology, as well as in algorithm development. In this study, we revisit and extend a framework for trajectory segmentation based on spatio-temporal criteria for this purpose. We adapt

  19. Segmental Colitis Complicating Diverticular Disease

    Directory of Open Access Journals (Sweden)

    Guido Ma Van Rosendaal

    1996-01-01

    Full Text Available Two cases of idiopathic colitis affecting the sigmoid colon in elderly patients with underlying diverticulosis are presented. Segmental resection has permitted close review of the histopathology in this syndrome which demonstrates considerable similarity to changes seen in idiopathic ulcerative colitis. The reported experience with this syndrome and its clinical features are reviewed.

  20. Leaf segmentation in plant phenotyping

    NARCIS (Netherlands)

    Scharr, Hanno; Minervini, Massimo; French, Andrew P.; Klukas, Christian; Kramer, David M.; Liu, Xiaoming; Luengo, Imanol; Pape, Jean Michel; Polder, Gerrit; Vukadinovic, Danijela; Yin, Xi; Tsaftaris, Sotirios A.

    2016-01-01

    Image-based plant phenotyping is a growing application area of computer vision in agriculture. A key task is the segmentation of all individual leaves in images. Here we focus on the most common rosette model plants, Arabidopsis and young tobacco. Although leaves do share appearance and shape