Pott's disease: a case of Mycobacterium xenopi infection of the spine.

Science.gov (United States)

Alfreijat, Majd; Ononiwu, Chiagozie; Sexton, Carlton

2012-01-01

Pott's disease is an infection of the spine with Mycobacterium tuberculosis that causes destruction of the spine elements resulting in progressive kyphosis. We are describing a rare case of Pott's disease where Mycobacterium xenopi was the inculpated organism.

Pott's disease: a case of Mycobacterium xenopi infection of the spine

Directory of Open Access Journals (Sweden)

Majd Alfreijat

2013-01-01

Full Text Available Pott's disease is an infection of the spine with Mycobacterium tuberculosis that causes destruction of the spine elements resulting in progressive kyphosis. We are describing a rare case of Pott's disease where Mycobacterium xenopi was the inculpated organism.

Three Cases of Spine Fractures after an Airplane Crash.

Science.gov (United States)

Lee, Han Joo; Moon, Bong Ju; Pennant, William A; Shin, Dong Ah; Kim, Keung Nyun; Yoon, Do Heum; Ha, Yoon

2015-10-01

While injuries to the spine after an airplane crash are not rare, most crashes result in fatal injuries. As such, few studies exist that reported on spine fractures sustained during airplane accidents. In this report, we demonstrate three cases of spine fractures due to crash landing of a commercial airplane. Three passengers perished from injuries after the crash landing, yet most of the passengers and crew on board survived, with injuries ranging from minor to severe. Through evaluating our three spine fracture patients, it was determined that compression fracture of the spine was the primary injury related to the airplane accident. The first patient was a 20-year-old female who sustained a T6-8 compression fracture without neurologic deterioration. The second patient was a 33-year-old female with an L2 compression fracture, and the last patient was a 49-year-old male patient with a T8 compression fracture. All three patients were managed conservatively and required spinal orthotics. During the crash, each of these patients were subjected to direct, downward high gravity z-axis (Gz) force, which gave rise to load on the spine vertically, thereby causing compression fracture. Therefore, new safety methods should be developed to prevent excessive Gz force during airplane crash landings.

Three Cases of Spine Fractures after an Airplane Crash

Science.gov (United States)

Lee, Han Joo; Moon, Bong Ju; Pennant, William A.; Shin, Dong Ah; Kim, Keung Nyun; Yoon, Do Heum

2015-01-01

While injuries to the spine after an airplane crash are not rare, most crashes result in fatal injuries. As such, few studies exist that reported on spine fractures sustained during airplane accidents. In this report, we demonstrate three cases of spine fractures due to crash landing of a commercial airplane. Three passengers perished from injuries after the crash landing, yet most of the passengers and crew on board survived, with injuries ranging from minor to severe. Through evaluating our three spine fracture patients, it was determined that compression fracture of the spine was the primary injury related to the airplane accident. The first patient was a 20-year-old female who sustained a T6-8 compression fracture without neurologic deterioration. The second patient was a 33-year-old female with an L2 compression fracture, and the last patient was a 49-year-old male patient with a T8 compression fracture. All three patients were managed conservatively and required spinal orthotics. During the crash, each of these patients were subjected to direct, downward high gravity z-axis (Gz) force, which gave rise to load on the spine vertically, thereby causing compression fracture. Therefore, new safety methods should be developed to prevent excessive Gz force during airplane crash landings. PMID:27169094

The magnetized sheath of a dusty plasma with grains size distribution

International Nuclear Information System (INIS)

Ou, Jing; Gan, Chunyun; Lin, Binbin; Yang, Jinhong

2015-01-01

The structure of a plasma sheath in the presence of dust grains size distribution (DGSD) is investigated in the multi-fluid framework. It is shown that effect of the dust grains with different sizes on the sheath structure is a collective behavior. The spatial distributions of electric potential, the electron and ion densities and velocities, and the dust grains surface potential are strongly affected by DGSD. The dynamics of dust grains with different sizes in the sheath depend on not only DGSD but also their radius. By comparison of the sheath structure, it is found that under the same expected value of DGSD condition, the sheath length is longer in the case of lognormal distribution than that in the case of uniform distribution. In two cases of normal and lognormal distributions, the sheath length is almost equal for the small variance of DGSD, and then the difference of sheath length increases gradually with increase in the variance

An unusual case of cycticercosis of the tendon sheath of the tendoachilles.

Directory of Open Access Journals (Sweden)

Sharat Agarwal

2010-04-01

Full Text Available Cysticercosis is an infection by the larval stage (cystcercus cellulosae of the cestode, Taenia Solium (pork tape worm, especially in those individuals who live in the endemic areas. After gaining entry into the body, the larvae become encysted and may lie in subcutaneous tissue, striated muscle, the vitreous humor, or other tissues. We report an unusual case of cysticercosis of the the tendon sheath of the tendoachilles that presented as a swelling of the tendoachilles. Upon Fine Needle Aspiration and Cytology (FNAC that were conducted preoperatively, the possibility of villonodular synovitis was identified. However, the cysticercosis diagnosis was confirmed later after an excisional biopsy was performed. We could find no reports in the literature concerning an occurrence of cysticercosis in the tendon sheath of tendoachilles.

Esophageal Perforation Following Anterior Cervical Spine Surgery: Case Report and Review of the Literature.

Science.gov (United States)

Hershman, Stuart H; Kunkle, William A; Kelly, Michael P; Buchowski, Jacob M; Ray, Wilson Z; Bumpass, David B; Gum, Jeffrey L; Peters, Colleen M; Singhatanadgige, Weerasak; Kim, Jin Young; Smith, Zachary A; Hsu, Wellington K; Nassr, Ahmad; Currier, Bradford L; Rahman, Ra'Kerry K; Isaacs, Robert E; Smith, Justin S; Shaffrey, Christopher; Thompson, Sara E; Wang, Jeffrey C; Lord, Elizabeth L; Buser, Zorica; Arnold, Paul M; Fehlings, Michael G; Mroz, Thomas E; Riew, K Daniel

2017-04-01

Multicenter retrospective case series and review of the literature. To determine the rate of esophageal perforations following anterior cervical spine surgery. As part of an AOSpine series on rare complications, a retrospective cohort study was conducted among 21 high-volume surgical centers to identify esophageal perforations following anterior cervical spine surgery. Staff at each center abstracted data from patients' charts and created case report forms for each event identified. Case report forms were then sent to the AOSpine North America Clinical Research Network Methodological Core for data processing and analysis. The records of 9591 patients who underwent anterior cervical spine surgery were reviewed. Two (0.02%) were found to have esophageal perforations following anterior cervical spine surgery. Both cases were detected and treated in the acute postoperative period. One patient was successfully treated with primary repair and debridement. One patient underwent multiple debridement attempts and expired. Esophageal perforation following anterior cervical spine surgery is a relatively rare occurrence. Prompt recognition and treatment of these injuries is critical to minimizing morbidity and mortality.

The importance of preoperative tissue sampling for mobile spine chordomas: literature review and report of two cases.

Science.gov (United States)

Zuccato, Jeffrey A; Witiw, Christopher D; Keith, Julia; Dyer, Erin; Saghal, Arjun; da Costa, Leodante

2018-01-01

Pre-operative biopsy and diagnosis of chordomas of the mobile spine is indicated as en bloc resections improve outcomes. This review of the management of mobile spine chordomas includes two cases of unexpected mobile spine chordomas where a preoperative tissue diagnosis was decided against and may have altered surgical decision-making. Two lumbar spine chordomas thought to be metastatic and primary bony lesions preoperatively were not biopsied before surgery and eventual pathology revealed chordoma. Preoperative diagnoses were questioned during surgery after an intraoperative tissue diagnosis of chordoma in one case and unclear pathology with non-characteristic tumor morphology in the other. The surgical plan was altered in these cases to maximize resection as en bloc resection reduces the risk of local recurrence in chordoma. Mobile spine chordomas are rare and en bloc resection is recommended, contrary to the usual approach to more common spine tumors. Since en bloc resection of spine chordomas improves disease free survival, it has been recommended that tissue diagnosis be obtained preoperatively when chordoma is considered in the differential diagnosis, in order to guide surgical planning. We present two cases where a preoperative biopsy was considered but not obtained after neuroradiology consultation and imaging review, which may have been managed differently if the diagnosis of spine chordomas were known pre-operatively.

MRI of the lumbar spine. Technical aspect. T2-weighted fat saturation coronal dynamic MRI of the lumbar spine; IRM du rachis lombaire. Aspects techniques. Coupe coronales en T2 et saturation de graisse IRM dynamique du rachis lombaire

Energy Technology Data Exchange (ETDEWEB)

Clarisse, J; Francke, J P; Leclet, H; Bourgeois, Ph; Chastanet, P; Cotten, A [Hopital Roger Salengro, 59 - Lille (France)

1998-06-01

Assess the feasibility of `dynamic` MRI of the lumbar spine and study the parameters of a single MRI sequence favorable for simultaneous imaging of the meningeal space and the epidural and foraminal venous system. Favor a decline in the number of sacco-radiculograms. Clinical assessment in the following circumstances: discordant clinical and and radiographic findings, difficulty in interpreting single or multiple disc-root conflicts, preoperative work-up in cases of narrow or stenotic lumbar canal. Dynamic MRI of the lumbar spine is possible if the hypothesis that the hyper-lordosis obtained in the supine position creates an anatomic and radiographic situation identical to the hyper-lordosis induced by the upright position is accepted. The `radiculo-phlebographic` sequence gives images of the root sheaths and the epidural, foraminal and extra-foraminal veins simultaneously, particularly in the coronal plane. (authors)

Double Level Extension-Distraction Thoracic Spine Injuries with Concomitant Double Level Sternal Fractures: A Case Report

Directory of Open Access Journals (Sweden)

CK Lee

2011-03-01

Full Text Available Extension-distraction injury of the spine is rare. A majority of these cases occur in the cervical region and at an isolated level. Rare instances of this injury have been described in an ankylosed or fused spine. This case report describes a rare two level extension-distraction thoracic spine injury in an otherwise healthy adult resulting from a motor vehicle accident.

A sheath model for arbitrary radiofrequency waveforms

Science.gov (United States)

Turner, M. M.; Chabert, Pascal

2012-10-01

The sheath is often the most important region of a rf plasma, because discharge impedance, power absorption and ion acceleration are critically affected by the behaviour of the sheath. Consequently, models of the sheath are central to any understanding of the physics of rf plasmas. Lieberman has supplied an analytical model for a radio-frequency sheath driven by a single frequency, but in recent years interest has been increasing in radio-frequency discharges excited by increasingly complex wave forms. There has been limited success in generalizing the Lieberman model in this direction, because of mathematical complexities. So there is essentially no sheath model available to describe many modern experiments. In this paper we present a new analytical sheath model, based on a simpler mathematical framework than that of Lieberman. For the single frequency case, this model yields scaling laws that are identical in form to those of Lieberman, differing only by numerical coefficients close to one. However, the new model may be straightforwardly solved for arbitrary current waveforms, and may be used to derive scaling laws for such complex waveforms. In this paper, we will describe the model and present some illustrative examples.

Unusual presentation of cactus spines in the flank of an elderly man: a case report

Directory of Open Access Journals (Sweden)

Freeman Scott

2010-05-01

Full Text Available Abstract Introduction Splinters and spines of plant matter are common foreign bodies in skin wounds of the extremities, and often present embedded in the dermis or subcutaneous tissue. Vegetative foreign bodies are highly inflammatory and, if not completely removed, can cause infection, toxic reactions, or granuloma formation. Older patients are at increased risk for infection from untreated plant foreign bodies. The most common error in plant splinter and spine management is failure to detect their presence. Case presentation Here we report a case of cactus spines in an 84-year-old Caucasian man presenting on the right flank as multiple, red papules with spiny extensions. This presentation was unusual both in location and the spinous character of the lesions, and only after punch biopsy analysis was a diagnosis of cactus matter spines made. Conclusions Our patient presented with an unusual case of cactus spines that required histopathology for identification. Skin lesions with neglected foreign bodies are a common cause of malpractice claims. If not removed, foreign bodies of the skin, particularly in elderly individuals, can result in inflammatory and infectious sequela. This report underscores the importance of thoroughly evaluating penetrating skin lesions for the presence of foreign bodies, such as splinters and spines.

Gorham-Stout syndrome of the spine. Case report and review of literature

International Nuclear Information System (INIS)

Floerchinger, A.; Boettger, E.; Claass-Boettger, F.; Harmes, J.

1998-01-01

Two female patients with Gorham-Stout syndrome (GSS) of the spine are described. One 25 year old patient developed progressive osteolysis of the upper cervical spine over a period of several years but despite gross extent of the disease had no neurological complications. Some bone implanted in order to stabilise the spine was absorbed after only a few weeks. A six year old girl with progressive osteolysis of the thoracic spine developed a reversible trans-section syndrome on several occasions. During an active episode, the spine was stabilised by a titanium implant. In both patients the condition arrested spontaneously. A review of the world literature (175 cases) has indicated that, including our two patients, there were only 15 patients with primary involvement of the spine and 27 patients with secondary involvement. The relatively good prognosis of the condition (mortality 13.3%), which often shows spontaneous arrest, becomes much worse if there is involvement of the spine or thorax because of neurological complications or a chylothorax. Involvement of the spine increases mortality to 33.3%, and to 52% if the thorax is involved. Early diagnosis and the institution of appropriate treatment is therefore essential. For involvement of the spine, a combination of radiotherapy and surgical stabilisation with a titanium implant should be performed since in nearly all patients bone transplants are reabsorbed. For this treatment the patient should be transferred to a neuro-orthopaedic centre. (orig.) [de

Hydatid disease of the spine: A rare case

Directory of Open Access Journals (Sweden)

Mona Agnihotri

2017-01-01

Full Text Available Hydatid disease or hydatidosis is the most widespread zoonosis caused by Echinococcus granulosus. Liver and lungs are the most common sites. Bone involvement is rare and reported in 0.5%–4% with spinal involvement reported in 50% of these cases. We present a case of spinal hydatidosis in a 35-year-old male presenting with lower extremity weakness and numbness. Magnetic resonance imaging (MRI of the spine showed multiple cystic lesions at the T9–T11 level with involvement of the paraspinal muscles. The lesion was seen intraspinal, intradural, intramedullary, and epidural. Radiological impression was aneurysmal bone cyst. The patient underwent laminectomy, and the excised cysts showed characteristic features of hydatid cyst (HC on histopathology. The patient was started on antihelminthic therapy postoperatively. MRI is a diagnostic modality for HC, but the unusual location and absence of characteristic features can cause diagnostic difficulty. A high index of suspicion should be kept in patients residing in endemic areas and presenting with unusual cystic lesion of spine.

Synovial chondromatosis of the lumbar spine with compressive myelopathy: a case report with review of the literature

International Nuclear Information System (INIS)

Abdelwahab, Ibrahim Fikry; Contractor, Daniel; Bianchi, Stefano; Hermann, George; Hoch, Benjamin

2008-01-01

Synovial chondromatosis has been rarely reported to occur in the spine with only one case found in the lumbar spine. We describe another case of synovial chondromatosis in the lumbar spine in a 41-year-old man who presented with compressive myelopathy. The tumor was located in the left ventrolateral corner of the epidural space just below the L 4 -L 5 intervertebral space. Besides being extremely rare, our case was unusual in that the juxtaposed facet joint was radiologically normal. (orig.)

Effect of collisions on photoelectron sheath in a gas

Science.gov (United States)

Sodha, Mahendra Singh; Mishra, S. K.

2016-02-01

This paper presents a study of the effect of the collision of electrons with atoms/molecules on the structure of a photoelectron sheath. Considering the half Fermi-Dirac distribution of photo-emitted electrons, an expression for the electron density in the sheath has been derived in terms of the electric potential and the structure of the sheath has been investigated by incorporating Poisson's equation in the analysis. The method of successive approximations has been used to solve Poisson's equation with the solution for the electric potential in the case of vacuum, obtained earlier [Sodha and Mishra, Phys. Plasmas 21, 093704 (2014)], being used as the zeroth order solution for the present analysis. The inclusion of collisions influences the photoelectron sheath structure significantly; a reduction in the sheath width with increasing collisions is obtained.

A prospective study of spine fractures diagnosed by total spine computed tomography in high energy trauma patients

International Nuclear Information System (INIS)

Takami, Masanari; Nohda, Kazuhiro; Sakanaka, Junya; Nakamura, Masamichi; Yoshida, Munehito

2011-01-01

Since it is known to be impossible to identify spinal fractures in high-energy trauma patients the primary trauma evaluation, we have been performing total spine computed tomography (CT) in high-energy trauma cases. We investigated the spinal fractures that it was possible to detect by total spine CT in 179 cases and evaluated the usefulness of total spine CT prospectively. There were 54 (30.2%) spinal fractures among the 179 cases. Six (37.5%) of the 16 cervical spine fractures that were not detected on plain X-ray films were identified by total spine CT. Six (14.0%) of 43 thoracolumbar spine fractures were considered difficult to diagnose based on the clinical findings if total spine CT had not been performed. We therefore concluded that total spine CT is very useful and should be performed during the primary trauma evaluation in high-energy trauma cases. (author)

30 CFR 816.15 - Casing and sealing of drilled holes: Permanent.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Casing and sealing of drilled holes: Permanent...-SURFACE MINING ACTIVITIES § 816.15 Casing and sealing of drilled holes: Permanent. When no longer needed... exploration hole, other drilled hole or borehole, well, and other exposed underground opening shall be capped...

Esophageal Perforation Following Anterior Cervical Spine Surgery: Case Report and Review of the Literature

OpenAIRE

Hershman, Stuart H.; Kunkle, William A.; Kelly, Michael P.; Buchowski, Jacob M.; Ray, Wilson Z.; Bumpass, David B.; Gum, Jeffrey L.; Peters, Colleen M.; Singhatanadgige, Weerasak; Kim, Jin Young; Smith, Zachary A.; Hsu, Wellington K.; Nassr, Ahmad; Currier, Bradford L.; Rahman, Ra?Kerry K.

2017-01-01

Study Design: Multicenter retrospective case series and review of the literature. Objective: To determine the rate of esophageal perforations following anterior cervical spine surgery. Methods: As part of an AOSpine series on rare complications, a retrospective cohort study was conducted among 21 high-volume surgical centers to identify esophageal perforations following anterior cervical spine surgery. Staff at each center abstracted data from patients? charts and created case report forms fo...

Cervical Spine pain as a presenting complaint in metastatic pancreatic cancer: a case report.

Science.gov (United States)

Rosenberg, Emily; Buchtel, Lindsey

2016-01-01

A 48 year-old female presented to her primary care physician with a two-month history of neck pain with negative cervical spine x-rays. During that office visit, the patient was noted to be tachycardic with EKG revealing ST depressions, which led to hospital admission. Acute coronary syndrome was ruled out, however, persistent neck pain warranted inpatient MRI of the cervical spine, which revealed a cervical spine lesion. Extensive investigation and biopsy ultimately confirmed stage IV pancreatic adenocarcinoma with metastases to the bone, liver, and likely lung. In the literature, the findings of a primary metastatic site being bone is rare with only a few case reports showing vertebral or sternal metastasis as the first clinical manifestation of pancreatic cancer. The uniqueness of this case lies in the only presenting complaint being cervical spine pain in the setting of extensive metastases to the liver, bone, and likely lung.

Percutaneous pedicle screw for unstable spine fractures in polytraumatized patients: A report of two cases

Directory of Open Access Journals (Sweden)

Boon Beng Tan

2012-01-01

Full Text Available Unstable spine fractures commonly occur in the setting of a polytraumatized patient. The aim of management is to balance the need for early operative stabilization and prevent additional trauma due to the surgery. Recent published literature has demonstrated the benefits of early stabilization of an unstable spine fracture particularly in patients with higher injury severity score (ISS. We report two cases of polytrauma with unstable spine fractures stabilized with a minimally invasive percutaneous pedicle screw instrumentation system as a form of damage control surgery. The patients had good recovery from the polytrauma injuries. These two cases illustrate the role of minimally invasive stabilization, its limitations and technical pitfalls in the management of unstable spine fractures in the polytrauma setting as a form of damage control surgery.

Anterior cervical spine surgery-associated complications in a retrospective case-control study

OpenAIRE

Tasiou, Anastasia; Giannis, Theofanis; Brotis, Alexandros G.; Siasios, Ioannis; Georgiadis, Iordanis; Gatos, Haralampos; Tsianaka, Eleni; Vagkopoulos, Konstantinos; Paterakis, Konstantinos; Fountas, Kostas N.

2017-01-01

Anterior cervical spine procedures have been associated with satisfactory outcomes. However, the occurrence of troublesome complications, although uncommon, needs to be taken into consideration. The purpose of our study was to assess the actual incidence of anterior cervical spine procedure-associated complications and identify any predisposing factors. A total of 114 patients undergoing anterior cervical procedures over a 6-year period were included in our retrospective, case-control study. ...

Clinical significance of gas myelography and CT gas myelography of the thoracic spine and the lumbar spine

International Nuclear Information System (INIS)

Yoshinaga, Haruhiko

1984-01-01

Basic and clinical applications relating to air myelography of the cervical spine have already been studied and extensively been used as an adjuvant diagnostic method for diseases of the spine and the spinal cord. However, hardly any application and clinical evaluation have been made concerning gas myelography of the thoracic spine and the lumbar spine. The author examined X-ray findings of 183 cases with diseases of the thoracic spine and the lumbar spine, including contral cases. Gas X-ray photography included simple profile, forehead tomography, sagittal plane, and CT section. Morphological characteristics of normal X-ray pictures of the throacic spine and the lumbar spine were explained from 54 control cases, and all the diameters of the subarachnoidal space from the anterior to the posterior part were measured. X-ray findings were examined on pathological cases, namely 22 cases with diseases of the throacic spine and 107 cases with diseases of the lumbar spine, and as a result these were useful for pathological elucidation of spinal cord tumors, spinal carries, yellow ligament ossification, lumbar spinal canal stenosis, hernia of intervertebral disc, etc. Also, CT gas myelography was excellent in stereoobservation of the spine and the spinal cord in spinal cord tumors, yellow ligament ossification, and spinal canal stenosis. On the other hand, it is not suitable for the diagnoses of intraspinal vascular abnormality, adhesive arachinitis, and running abnormality of the cauda equina nerve and radicle. Gas myelography of the thoracic spine and the lambar spine, is very useful in clinics when experienced techniques are used in photographic conditions, and diagnoses are made, well understanding the characteristics of gas pictures. Thus, its application has been opened to selection of an operative technique, determination of operative ranges, etc. (J.P.N.)

Clinical significance of gas myelography and CT gas myelography of the thoracic spine and the lumbar spine

Energy Technology Data Exchange (ETDEWEB)

Yoshinaga, Haruhiko (Tokyo Medical Coll. (Japan))

1984-05-01

Basic and clinical applications relating to air myelography of the cervical spine have already been studied and extensively been used as an adjuvant diagnostic method for diseases of the spine and the spinal cord. However, hardly any application and clinical evaluation have been made concerning gas myelography of the thoracic spine and the lumbar spine. The author examined X-ray findings of 183 cases with diseases of the thoracic spine and the lumbar spine, including contral cases. Gas X-ray photography included simple profile, forehead tomography, sagittal plane, and CT section. Morphological characteristics of normal X-ray pictures of the throacic spine and the lumbar spine were explained from 54 control cases, and all the diameters of the subarachnoidal space from the anterior to the posterior part were measured. X-ray findings were examined on pathological cases, namely 22 cases with diseases of the throacic spine and 107 cases with diseases of the lumbar spine, and as a result these were useful for pathological elucidation of spinal cord tumors, spinal carries, yellow ligament ossification, lumbar spinal canal stenosis, hernia of intervertebral disc, etc. Also, CT gas myelography was excellent in stereo observation of the spine and the spinal cord in spinal cord tumors, yellow ligament ossification, and spinal canal stenosis. On the other hand, it is not suitable for the diagnoses of intraspinal vascular abnormality, adhesive arachinitis, and running abnormality of the cauda equina nerve and radicle. Gas myelography of the thoracic spine and the lambar spine, is very useful in clinics when experienced techniques are used in photographic conditions, and diagnoses are made, well understanding the characteristics of gas pictures. Thus, its application has been opened to selection of an operative technique, determination of operative ranges, etc.

Malignant peripheral nerve sheath tumour of the bladder associated with neurofibromatosis I.

LENUS (Irish Health Repository)

O'Brien, Julie

2008-12-01

Neurofibromatosis is a hamartomatous disorder of autonomic peripheral nerve sheaths associated with peripheral nerve sheath tumours. Most tumours are neurofibromas; however, the genitourinary system is rarely involved. We present a rare case of a nerve sheath tumour of the bladder in a young patient, which was discovered to be malignant.

CANDU fuel sheath integrity and oxide layer thickness determination by Eddy current technique

International Nuclear Information System (INIS)

Gheorghe, Gabriela; Man, Ion; Parvan, Marcel; Valeca, Serban

2010-01-01

This paper presents results concerning the integrity assessment of the fuel elements cladding and measurements of the oxide layer on sheaths, using the eddy current technique. Flaw detection using eddy current provides information about the integrity of fuel element sheath or presence of defects in the sheath produced by irradiation. The control equipment consists of a flaw detector with eddy currents, operable in the frequency range 10 Hz to 10 MHz, and a differential probe. The calibration of the flaw detector is done using artificial defects (longitudinal, transversal, external and internal notches, bored and unbored holes) obtained on Zircaloy-4 tubes identical to those out of which the sheath of the CANDU fuel element is manufactured (having a diameter of 13.08 mm and a wall thickness of 0.4 mm). When analyzing the behavior of the fuel elements' cladding facing the corrosion is important to know the thickness of the zirconium oxide layer. The calibration of the device measuring the thickness of the oxide layer is done using a Zircaloy-4 tube identical to that which the cladding of the CANDU fuel element is manufactured of, and calibration foils, as well. (authors)

TU-A-BRB-00: PANEL DISCUSSION: SBRT/SRS Case Studies - Brain and Spine

Energy Technology Data Exchange (ETDEWEB)

NONE

2016-06-15

Brain stereotactic radiosurgery (SRS) and spine stereotactic body radiation therapy (SBRT) are commonly treated by a multidisciplinary team of neurosurgeons, radiation oncologists, and medical physicists. However the treatment objectives, constraints, and technical considerations involved can be quite different between the two techniques. In this interactive session an expert panel of speakers will present clinical brain SRS and spine SBRT cases in order to demonstrate real-world considerations for ensuring safe and accurate treatment delivery and to highlight the significant differences in approach for each treatment site. The session will include discussion of topic such as clinical indications, immobilization, target definition, normal tissue tolerance limits, and beam arrangements. Learning Objectives: Understand the differences in indications and dose/fractionation strategies for intracranial SRS and spine SBRT. Describe the different treatment modalities which can be used to deliver intracranial SRS and spine SBRT. Cite the major differences in treatment setup and delivery principles between intracranial and spine treatments. Identify key critical structures and clinical dosimetric tolerance levels for spine SBRT and intracranial SRS. Understand areas of ongoing work to standardize intracranial SRS and spine SBRT procedures. Schlesinger: Research support: Elekta Instruments, AB; D. Schlesinger, Elekta Instruments, AB - research support; B. Winey, No relevant external funding for this subject.

TU-A-BRB-00: PANEL DISCUSSION: SBRT/SRS Case Studies - Brain and Spine

International Nuclear Information System (INIS)

2016-01-01

Brain stereotactic radiosurgery (SRS) and spine stereotactic body radiation therapy (SBRT) are commonly treated by a multidisciplinary team of neurosurgeons, radiation oncologists, and medical physicists. However the treatment objectives, constraints, and technical considerations involved can be quite different between the two techniques. In this interactive session an expert panel of speakers will present clinical brain SRS and spine SBRT cases in order to demonstrate real-world considerations for ensuring safe and accurate treatment delivery and to highlight the significant differences in approach for each treatment site. The session will include discussion of topic such as clinical indications, immobilization, target definition, normal tissue tolerance limits, and beam arrangements. Learning Objectives: Understand the differences in indications and dose/fractionation strategies for intracranial SRS and spine SBRT. Describe the different treatment modalities which can be used to deliver intracranial SRS and spine SBRT. Cite the major differences in treatment setup and delivery principles between intracranial and spine treatments. Identify key critical structures and clinical dosimetric tolerance levels for spine SBRT and intracranial SRS. Understand areas of ongoing work to standardize intracranial SRS and spine SBRT procedures. Schlesinger: Research support: Elekta Instruments, AB; D. Schlesinger, Elekta Instruments, AB - research support; B. Winey, No relevant external funding for this subject.

A Large Asymptomatic Thoracic Spine Schwannoma Detected Incidentally by {sup 18}F-FDG PET/CT: A Case Report

Energy Technology Data Exchange (ETDEWEB)

Bahk, Yong Whee [Seoul Sungae Hospital, Seoul (Korea, Republic of); Yoo, Ie Ryung [Catholic University Medical School Hospital, Seoul (Korea, Republic of)

2008-10-15

Schwannoma is not a rare tumor occurring anywhere where sheathed nerve fibers present. However the spinal involvement has been noted to be uncommon. The use of PET in the diagnosis of spinal schwannomas seemed to have only sporadically been reported and standardized uptake values (SUV) measured in peripheral nerves schwannomas varied according to cellularity. Most reported spinal schwannoms were symptomatic and relatively hypometabolic but ours differed in that despite considerable compression of the spinal cord it did not produce clinical symptoms or signs and had a relatively high FDG uptake value. The spine was operated. On opening a 1.0x1.5 cm tumor was found to be encapsulated and located in the right posterolateral aspect of the intradural space at the 4th thoracic spine level. It was completely resected along with the rootlet from which the tumor seemed to have originated not damaging the cord or causing bleeding. The spinal medulla compressed by and adherent to the tumor was decompressed and released following arachnoid adhesiolysis. The hospital stay was uneventful. Patient was discharged and is well and fine without complication eight months after surgery.

30 CFR 816.14 - Casing and sealing of drilled holes: Temporary.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Casing and sealing of drilled holes: Temporary. 816.14 Section 816.14 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT...-SURFACE MINING ACTIVITIES § 816.14 Casing and sealing of drilled holes: Temporary. Each exploration hole...

30 CFR 816.13 - Casing and sealing of drilled holes: General requirements.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Casing and sealing of drilled holes: General...-SURFACE MINING ACTIVITIES § 816.13 Casing and sealing of drilled holes: General requirements. Each exploration hole, other drill or borehole, well, or other exposed underground opening shall be cased, sealed...

Contrast material filling of the peroneal tendon sheath

International Nuclear Information System (INIS)

Zadravecz, Gy.; Grexa, E.

1981-01-01

In case of complaints after fracture of the calcaneus the common sheath of the peroneus tendons was filled up with contrast material. The tendon sheath was punctured Oehind the external ankle. The three-directional radiograms clearly showed the dislocation and compression of the tendons, caused by the exostosis of the calcaneus. The concomitant tendovaginitis caused the complaints. This alteration was observed in 11% of all the calcaneus fractures. (L.E.)

Farris-Tang retractor in optic nerve sheath decompression surgery.

Science.gov (United States)

Spiegel, Jennifer A; Sokol, Jason A; Whittaker, Thomas J; Bernard, Benjamin; Farris, Bradley K

2016-01-01

Our purpose is to introduce the use of the Farris-Tang retractor in optic nerve sheath decompression surgery. The procedure of optic nerve sheath fenestration was reviewed at our tertiary care teaching hospital, including the use of the Farris-Tang retractor. Pseudotumor cerebri is a syndrome of increased intracranial pressure without a clear cause. Surgical treatment can be effective in cases in which medical therapy has failed and disc swelling with visual field loss progresses. Optic nerve sheath decompression surgery (ONDS) involves cutting slits or windows in the optic nerve sheath to allow cerebrospinal fluid to escape, reducing the pressure around the optic nerve. We introduce the Farris-Tang retractor, a retractor that allows for excellent visualization of the optic nerve sheath during this surgery, facilitating the fenestration of the sheath and visualization of the subsequent cerebrospinal fluid egress. Utilizing a medial conjunctival approach, the Farris-Tang retractor allows for easy retraction of the medial orbital tissue and reduces the incidence of orbital fat protrusion through Tenon's capsule. The Farris-Tang retractor allows safe, easy, and effective access to the optic nerve with good visualization in optic nerve sheath decompression surgery. This, in turn, allows for greater surgical efficiency and positive patient outcomes.

Two cases of congenital defects within transverse processes of lumbar spine

International Nuclear Information System (INIS)

Malawski, S.; Sokolski, B.

1993-01-01

Two cases of congenital defects of transverse processes of lumbar spine causing lumbalgia are described. The first one was produced by direct contact of the elongated processes with subsequent pseudoarthrosis. Hypertrophied processes caused stenosis around intervertebral foramen and irritated posterior neural branch in the second case. Surgical resection of the hypertrophied transverse processes has brought the cure. (author)

A game of two discs: a case of non-contiguous and occult cervical spine injury in a rugby player

OpenAIRE

O'Sullivan, Michael D.; Piggot, Robert; Jaddan, Mutaz; McCabe, John P.

2016-01-01

The aim of this case report was to highlight the application of magnetic resonance imaging (MRI) in elucidating serious and occult injuries in a single case of hyperflextion injury of a patient cervical spine (C-Spine). A chart and radiology review was performed to establish the sequence of care and how the results of imaging studies influenced the clinical management in this trauma case. Plain radiographs and computed tomography (CT) imaging modalities of the C-Spine revealed bilateral C4/C5...

AC losses of single-core MgB{sub 2} wires with different metallic sheaths

Energy Technology Data Exchange (ETDEWEB)

Kováč, J., E-mail: elekjkov@savba.sk; Šouc, J.; Kováč, P.; Hušek, I.

2015-12-15

Highlights: • AC losses in single-core MgB{sub 2} wires with different metallic sheaths have been measured. • It has been shown that metallic sheath can affect the measured AC loss considerably. • GlidCop and Stainless Steel have negligible effect to the overall loss. • Strong contribution of eddy currents has been found in the wire with well conductive copper sheath. • Due to Monel sheath AC loss of MgB{sub 2} core is not visible. - Abstract: AC losses of single-core MgB{sub 2} superconductors with different metallic sheaths (Cu, GlidCop, stainless steel and Monel) have been measured and analyzed. These wires were exposed to external magnetic field with frequencies 72 and 144 Hz and amplitudes up to 0.1 T at temperatures ranged from 18 to 40 K. The obtained results have shown that applied metallic sheath can affect the measured AC loss considerably. In the case of GlidCop and Stainless Steel a negligible small effect of metallic sheath was observed. Strong contribution of eddy currents has been found in the wire with well conductive copper sheath. In the case of Monel sheath, the hysteresis loss of magnetic sheath is dominated and AC loss of MgB{sub 2} core is practically not visible.

Non traumatic fractures of the lumbar spine and seizures: case report

Directory of Open Access Journals (Sweden)

Moscote-Salazar Luis Rafael

2015-12-01

Full Text Available Injury-induced seizures may appear clinically asymptomatic and can be easily monitored by the absence of trauma and post-ictal impairment of consciousness. Patients with epilepsy have a higher risk of compression fractures, leading to serious musculoskeletal injuries, this type of non-traumatic compression fractures of the spine secondary to seizures are rare lesions, and is produced by the severe contraction of the paraspinal muscles that can achieve the thoracic spine fracture. Seizures induced lesions may appear clinically asymptomatic and can be easily monitored by the absence of trauma and post-ictal impairment of consciousness. We present a case report.

Case Series of an Intraoral Balancing Appliance Therapy on Subjective Symptom Severity and Cervical Spine Alignment

Directory of Open Access Journals (Sweden)

Young Jun Lee

2013-01-01

Full Text Available Objective. The objective of this study was to investigate the effect of a holistic intraoral appliance (OA on cervical spine alignment and subjective symptom severity. Design. An observational study on case series with holistic OA therapy. Setting. An outpatient clinic for holistic temporomandibular joint (TMJ therapy under the supervision of the Pain Center, CHA Biomedical center, CHA University. Subjects. Ambulatory patients presenting with diverse chief complaints in the holistic TMJ clinic. Main Measures. Any immediate change in the curvature of cervical spine and the degree of atlantoaxial rotation was investigated in the images of simple X-ray and computed tomography of cervical spine with or without OA. Changes of subjective symptom severity were also analyzed for the holistic OA therapy cases. Results. A total of 59 cases were reviewed. Alignment of upper cervical spine rotation showed an immediate improvement (. Changes of subjective symptom severity also showed significant improvement (. Conclusion. These cases revealed rudimentary clinical evidence that holistic OA therapy may be related to an alleviated symptom severity and an improved cervical spinal alignment. These results show that further researches may warrant for the holistic TMJ therapy.

Esophageal perforation associated with cervical spine surgery: Report of two cases and review of the literature

NARCIS (Netherlands)

Vrouenraets, B. C.; Been, H. D.; Brouwer-Mladin, R.; Bruno, M.; van Lanschot, J. J. B.

2004-01-01

Background/Aims: Esophageal perforation after anterior cervical spine surgery is a rare complication with various clinical presentations and treatments. Methods: Two cases of esophageal perforation after anterior cervical spine surgery are described, one occurring in the immediate postoperative

Nonradial and nonpolytropic astrophysical outflows. X. Relativistic MHD rotating spine jets in Kerr metric

Science.gov (United States)

Chantry, L.; Cayatte, V.; Sauty, C.; Vlahakis, N.; Tsinganos, K.

2018-04-01

Context. High-resolution radio imaging of active galactic nuclei (AGN) has revealed that the jets of some sources present superluminal knots and transverse stratification. Recent observational projects, such as ALMA and γ-ray telescopes, such as HESS and HESS2 have provided new observational constraints on the central regions of rotating black holes in AGN, suggesting that there is an inner- or spine-jet surrounded by a disk wind. This relativistic spine-jet is likely to be composed of electron-positron pairs extracting energy from the black hole and will be explored by the future γ-ray telescope CTA. Aims: In this article we present an extension to and generalization of relativistic jets in Kerr metric of the Newtonian meridional self-similar mechanism. We aim at modeling the inner spine-jet of AGN as a relativistic light outflow emerging from a spherical corona surrounding a Kerr black hole and its inner accretion disk. Methods: The model is built by expanding the metric and the forces with colatitude to first order in the magnetic flux function. As a result of the expansion, all colatitudinal variations of the physical quantities are quantified by a unique parameter. Unlike previous models, effects of the light cylinder are not neglected. Results: Solutions with high Lorentz factors are obtained and provide spine-jet models up to the polar axis. As in previous publications, we calculate the magnetic collimation efficiency parameter, which measures the variation of the available energy across the field lines. This collimation efficiency is an integral part of the model, generalizing the classical magnetic rotator efficiency criterion to Kerr metric. We study the variation of the magnetic efficiency and acceleration with the spin of the black hole and show their high sensitivity to this integral. Conclusions: These new solutions model collimated or radial, relativistic or ultra-relativistic outflows in AGN or γ-ray bursts. In particular, we discuss the

Delayed Esophageal Pseudodiverticulum after Anterior Cervical Spine Fixation: Report of 2 Cases

Directory of Open Access Journals (Sweden)

Ali Sadrizadeh

2015-03-01

Full Text Available Introduction: Although perforation of the esophagus, in the anterior cervical spine fixation, is well established, cases with delayed onset, especially cases that present pseudodiverticulum, are not common. In addition, management of the perforation in this situation is debated.  Case Report:   Delayed esophageal pseudodiverticulum was managed in two patients with a history of anterior spine fixation. Patients were operated on, the loose plate and screws were extracted, the wall of the diverticulum was excised, the perforation on the nasogastric tube was suboptimally repaired, and a closed suction drain was placed there. The NGT was removed on the 7th day and barium swallow demonstrated no leakage at the operation site; therefore, oral feeding was started without any problem.  Conclusion:  In cases with delayed perforation, fistula, or diverticulum removal of anterior fixation instruments, gentle repair of the esophageal wall without persistence on definitive and optimal perforation closure, wide local drainage, early enteral nutrition via NGT, and antibiotic prescription is suggested.

Thyroid storm following anterior cervical spine surgery for tuberculosis of cervical spine

Directory of Open Access Journals (Sweden)

Sanjiv Huzurbazar

2014-01-01

Full Text Available Objective: The primary objective was to report this rare case and discuss the probable mechanism of thyroid storm following anterior cervical spine surgery for Kochs cervical spine.

Tophaceous gout of the lumbar spine in a renal transplant patient: a case report and literature review

International Nuclear Information System (INIS)

Thornton, Frank J.; Torreggiani, William C.; Brennan, Paul

2000-01-01

Tophaceous gout of the spine is rare. We report the case of a 27-year-old male, renal transplant recipient, who presented with an acute onset of lower back pain. Radiological, biochemical and histo-pathological findings confirmed a diagnosis of tophaceous gout of the lumbar spine. We present the case history with the radiological findings and discuss the literature

A game of two discs: a case of non-contiguous and occult cervical spine injury in a rugby player.

Science.gov (United States)

O'Sullivan, Michael D; Piggot, Robert; Jaddan, Mutaz; McCabe, John P

2016-03-14

The aim of this case report was to highlight the application of magnetic resonance imaging (MRI) in elucidating serious and occult injuries in a single case of hyperflextion injury of a patient cervical spine (C-Spine). A chart and radiology review was performed to establish the sequence of care and how the results of imaging studies influenced the clinical management in this trauma case. Plain radiographs and computed tomography (CT) imaging modalities of the C-Spine revealed bilateral C4/C5 facetal subluxation with no obvious fractures; however, the MR imaging of the C-Spine revealed a non-contiguous and occult injury to C6/C7 disc with a posterior annular tear and associated disc extrusion. This altered the operative intervention that was initially planned. MR imaging proved an invaluable diagnostic addition in this particular case of cervical trauma in a rugby player following a hyperflextion injury, by revealing a serious non-contiguous and occult injury of the C-Spine. Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author 2016.

Dysphagia produced by cervical spine osteophyte. A case report

Directory of Open Access Journals (Sweden)

Claudio Silveri

2014-01-01

Full Text Available We present a case of a 73-year-old male patient with progressive dysphagia, and hoarseness (irritability in the throat. He was studied with the appropriate imaging techniques, and esophagoscopy led to a diagnosis of extrinsic esophageal dysphagia for osteophyte obstruction of the cervical spine due to the arthrosis. A surgical resection was performed, without complications. Some considerations are given on this theme.

Chondroblastoma of the thoracic spine: a rare location. Case report with radiologic-pathologic correlation

Energy Technology Data Exchange (ETDEWEB)

Venkatasamy, A. [University Hospital of Strasbourg, Department of Radiology, Strasbourg (France); Chenard, M.P. [University Hospital of Strasbourg, Department of Pathology, Strasbourg (France); Massard, G. [University Hospital of Strasbourg, Department of Thoracic Surgery, Strasbourg (France); Steib, J.P. [University Hospital of Strasbourg, Department of Spine Surgery, Strasbourg (France); Bierry, G. [University Hospital of Strasbourg, Department of Radiology, Strasbourg (France); University Hospital of Strasbourg, Department of Pathology, Strasbourg (France); University Hospital of Strasbourg, Department of Thoracic Surgery, Strasbourg (France); University Hospital of Strasbourg, Department of Spine Surgery, Strasbourg (France)

2017-03-15

Chondroblastoma is a rare benign cartilage neoplasm that arises from the appendicular skeleton in the vast majority of the cases (80%). Chondroblastoma of the spine is an even more rare condition (30 cases reported), and vertebral chondroblastomas, unlike chondroblastomas of the extremities, present with the appearance of an aggressive tumor on CT and MR imaging and occur at least a decade later. Even though vertebral chondroblastomas are very uncommon tumors, they should nonetheless be included in the differential diagnosis when encountered with an aggressive vertebral mass, and a histological confirmation should be performed. We present a case of chondroblastoma of the thoracic spine of a 27-year-old female for which detailed radiologic-pathologic correlation was obtained. (orig.)

Simulations of rf-driven sheath formation in two dimensions

International Nuclear Information System (INIS)

Riyopoulos, S.; Grossmann, W.; Drobot, A.; Kress, M.

1992-01-01

The results from two-dimensional particle simulations of sheath formation around periodic metal arrays placed inside magnetized plasmas and driven by oscillating voltages are reported. The main goal is the modeling of the plasma interaction with the Faraday bars surrounding the antennas during ion cyclotron tokamak heating. The study of the time-averaged potentials shows that the two-dimensional sheath structure depends on both the sheath length-to-thickness ratio and the inclination of the magnetic lines. The equipotential surfaces form closed, nested cells between adjacent bars. When the magnetic lines are nearly perpendicular to the potential gradients, the ion motion is dominated by the ExB drift, and ion streamlines form vortices around the equipotentials. At larger inclinations of the magnetic lines, the flow decouples from the equipotentials and ion transport is mainly along the potential gradients. The critical angle for the transition from vortex circulation to field aligned flow is computed. The effects of the cross-field ion transport on the sheath properties are discussed. It is shown that the sheath length and the magnetic line inclination affect the sheath scaling in the two-dimensional case. The one-dimensional theory results are recovered in the limit of high length-to-thickness ratio and large inclination of the magnetic lines

Communication through plasma sheaths

International Nuclear Information System (INIS)

Korotkevich, A. O.; Newell, A. C.; Zakharov, V. E.

2007-01-01

We wish to transmit messages to and from a hypersonic vehicle around which a plasma sheath has formed. For long distance transmission, the signal carrying these messages must be necessarily low frequency, typically 2 GHz, to which the plasma sheath is opaque. The idea is to use the plasma properties to make the plasma sheath appear transparent

Comparative analysis of cervical spine management in a subset of severe traumatic brain injury cases using computer simulation.

Directory of Open Access Journals (Sweden)

Kimbroe J Carter

Full Text Available BACKGROUND: No randomized control trial to date has studied the use of cervical spine management strategies in cases of severe traumatic brain injury (TBI at risk for cervical spine instability solely due to damaged ligaments. A computer algorithm is used to decide between four cervical spine management strategies. A model assumption is that the emergency room evaluation shows no spinal deficit and a computerized tomogram of the cervical spine excludes the possibility of fracture of cervical vertebrae. The study's goal is to determine cervical spine management strategies that maximize brain injury functional survival while minimizing quadriplegia. METHODS/FINDINGS: The severity of TBI is categorized as unstable, high risk and stable based on intracranial hypertension, hypoxemia, hypotension, early ventilator associated pneumonia, admission Glasgow Coma Scale (GCS and age. Complications resulting from cervical spine management are simulated using three decision trees. Each case starts with an amount of primary and secondary brain injury and ends as a functional survivor, severely brain injured, quadriplegic or dead. Cervical spine instability is studied with one-way and two-way sensitivity analyses providing rankings of cervical spine management strategies for probabilities of management complications based on QALYs. Early collar removal received more QALYs than the alternative strategies in most arrangements of these comparisons. A limitation of the model is the absence of testing against an independent data set. CONCLUSIONS: When clinical logic and components of cervical spine management are systematically altered, changes that improve health outcomes are identified. In the absence of controlled clinical studies, the results of this comparative computer assessment show that early collar removal is preferred over a wide range of realistic inputs for this subset of traumatic brain injury. Future research is needed on identifying factors in

SpineData

DEFF Research Database (Denmark)

Kent, Peter; Kongsted, Alice; Jensen, Tue Secher

2015-01-01

Background: Large-scale clinical registries are increasingly recognized as important resources for quality assurance and research to inform clinical decision-making and health policy. We established a clinical registry (SpineData) in a conservative care setting where more than 10,000 new cases...... of spinal pain are assessed each year. This paper describes the SpineData registry, summarizes the characteristics of its clinical population and data, and signals the availability of these data as a resource for collaborative research projects. Methods: The SpineData registry is an Internet-based system...... that captures patient data electronically at the point of clinical contact. The setting is the government-funded Medical Department of the Spine Centre of Southern Denmark, Hospital Lillebaelt, where patients receive a multidisciplinary assessment of their chronic spinal pain. Results: Started in 2011...

Surgical Site Infections in Pediatric Spine Surgery: Comparative Microbiology of Patients with Idiopathic and Nonidiopathic Etiologies of Spine Deformity.

Science.gov (United States)

Maesani, Matthieu; Doit, Catherine; Lorrot, Mathie; Vitoux, Christine; Hilly, Julie; Michelet, Daphné; Vidal, Christophe; Julien-Marsollier, Florence; Ilharreborde, Brice; Mazda, Keyvan; Bonacorsi, Stéphane; Dahmani, Souhayl

2016-01-01

Surgical site infections (SSIs) are a concern in pediatric spine surgery with unusually high rates for a clean surgery and especially for patients with deformity of nonidiopathic etiology. Microbiologic differences between etiologies of spine deformities have been poorly investigated. We reviewed all cases of SSI in spinal surgery between 2007 and 2011. Characteristics of cases and of bacteria according to the etiology of the spine disease were investigated. Of 496 surgeries, we identified 51 SSIs (10.3%) in 49 patients. Staphylococcus aureus was the most frequent pathogen whatever the etiology (n = 31, 61% of infection cases). The second most frequent pathogens vary according to the etiology of the spine deformity. It was Gram-negative bacilli (GNB) in nonidiopathic cases (n = 19, 45% of cases) and anaerobe in idiopathic cases (n = 8, 38% of cases), particularly Gram-positive anaerobic cocci (n = 5, 24% of cases). Infection rate was 6.8% in cases with idiopathic spine disease (n = 21) and 15.9% in cases with nonidiopathic spine disease (n = 30). Nonidiopathic cases were more frequently male with lower weight. American Society of Anesthesiologists score was more often greater than 2, they had more frequently sacral implants and postoperative intensive care unit stay. GNB were significantly associated with a nonidiopathic etiology, low weight, younger age and sacral fusion. SSIs were polymicrobial in 31% of cases with a mean of 1.4 species per infection cases. S. aureus is the first cause of SSI in pediatric spine surgery. However, Gram-positive anaerobic cocci should be taken into account in idiopathic patients and GNB in nonidiopathic patients when considering antibiotic prophylaxis and curative treatment.

Early MRI findings in stab wound of the cervical spine: two case reports

Energy Technology Data Exchange (ETDEWEB)

Alkan, A.; Baysal, T.; Sarac, K.; Sigirci, A.; Kutlu, R. [Inonu Universitesi Turgut Ozal Tip Merkezi, Radyoloji Anabilim Dali, Malatya (Turkey)

2002-01-01

MR imaging was found to be the most sensitive modality for the detection of spinal cord abnormalities in the acutely injured spine. Although it is reported that traumatic pneumomyelogram indicates a base-of-skull or middle cranial fossa fracture and is almost certainly associated with intracranial subarachnoid air, early MR imaging may demonstrate subarachnoid air in penetrating trauma of the spinal cord without head injury. We report two cervical-spine stab-wound cases, one of which had subarachnoid air on early MR findings. (orig.)

Bilateral giant cell tumor of tendon sheath of tendoachilles

Directory of Open Access Journals (Sweden)

Soma Datta

2014-01-01

Full Text Available Giant cell tumor of tendon sheath arises from the synovium of tendon sheaths, joints, or bursae, mostly affects adults between 30 and 50 years of age, and is slightly more common in females. We report the case of a 32-years-old male presenting with pain in both ankles without any history of trauma. On clinical examination, tenderness on both tendoachilles and local thickening were observed. Ultrasonography showed thickening of local tendinous area with increase in anteroposterior diameter, and Doppler demonstrated increased flow in peritendinous area. MRI findings showed that most of the tumor had intermediate signal intensity and portions of the tumor had low signal intensity. Fine needle aspiration cytology confirmed the diagnosis of giant cell tumor of tendon sheath. Excision biopsy was done with no recurrence on five month follow-up. Review of literature did not reveal any similar result; so, bilateral giant cell tumor of tendon sheath of tendoachilles is a rare presentation.

Effect of additional holes on transient thermal fatigue life of gas turbine casing

Directory of Open Access Journals (Sweden)

H. Bazvandi

2017-10-01

Full Text Available Gas turbines casings are susceptible to cracking at the edge of eccentric pin hole, which is the most likely position for crack initiation and propagation. This paper describes the improvement of transient thermal fatigue crack propagation life of gas turbines casings through the application of additional holes. The crack position and direction was determined using non-destructive tests. A series of finite element patterns were developed and tested in ASTM-A395 elastic perfectly-plastic ductile cast iron. The effect of arrangement of additional holes on transient thermal fatigue behavior of gas turbines casings containing hole edge cracks was investigated. ABAQUS finite element package and Zencrack fracture mechanics code were used for modeling. The effect of the reduction of transient thermal stress distribution around the eccentric pin hole on the transient thermal fatigue crack propagation life of the gas turbines casings was discussed. The result shows that transient thermal fatigue crack propagation life could be extended by applying additional holes of larger diameter and decreased by increasing the vertical distance, angle, and distance between the eccentric pin hole and the additional holes. The results from the numerical predictions were compared with experimental data.

Cased-hole log analysis and reservoir performance monitoring

CERN Document Server

Bateman, Richard M

2015-01-01

This book addresses vital issues, such as the evaluation of shale gas reservoirs and their production. Topics include the cased-hole logging environment, reservoir fluid properties; flow regimes; temperature, noise, cement bond, and pulsed neutron logging; and casing inspection. Production logging charts and tables are included in the appendices. The work serves as a comprehensive reference for production engineers with upstream E&P companies, well logging service company employees, university students, and petroleum industry training professionals. This book also: ·       Provides methods of conveying production logging tools along horizontal well segments as well as measurements of formation electrical resistivity through casing ·       Covers new information on fluid flow characteristics in inclined pipe and provides new and improved nuclear tool measurements in cased wells ·       Includes updates on cased-hole wireline formation testing  

Revisiting the plasma sheath—dust in plasma sheath

Energy Technology Data Exchange (ETDEWEB)

Das, G. C. [Mathematical Science Division, IASST, Guwahati 781014 (India); Deka, R.; Bora, M. P., E-mail: mpbora@gauhati.ac.in [Physics Department, Gauhati University, Guwahati 781014 (India)

2016-04-15

In this work, we have considered the formation of warm plasma sheath in the vicinity of a wall in a plasma with considerable presence of dust particles. As an example, we have used the parameters relevant in case of plasma sheath formed around surfaces of various solid bodies in space, though the results obtained in this work can be applied to any other physical situation such as laboratory plasma. In the ion-acoustic time scale, we neglect the dust dynamics. The dust particles affect the sheath dynamics by affecting the Poisson equation which determines the plasma potential in the sheath region. It is important to note that our calculations are valid only when the amount of dust particles is not sufficient so as to affect the plasma dynamics in the dust-acoustic time scale, but enough to affect the plasma sheath. We have assumed the current to a dust particle to be balanced throughout the analysis. This makes the grain potential dependent on plasma potential, which is then incorporated into the Poisson equation. The resultant numerical model becomes an initial value problem, which is described by a 1-D integro-differential equation, which is then solved self-consistently by incorporating the change in plasma potential caused by inclusion of the dust potential in the Poisson equation.

Anterior cervical spine surgery-associated complications in a retrospective case-control study.

Science.gov (United States)

Tasiou, Anastasia; Giannis, Theofanis; Brotis, Alexandros G; Siasios, Ioannis; Georgiadis, Iordanis; Gatos, Haralampos; Tsianaka, Eleni; Vagkopoulos, Konstantinos; Paterakis, Konstantinos; Fountas, Kostas N

2017-09-01

Anterior cervical spine procedures have been associated with satisfactory outcomes. However, the occurrence of troublesome complications, although uncommon, needs to be taken into consideration. The purpose of our study was to assess the actual incidence of anterior cervical spine procedure-associated complications and identify any predisposing factors. A total of 114 patients undergoing anterior cervical procedures over a 6-year period were included in our retrospective, case-control study. The diagnosis was cervical radiculopathy, and/or myelopathy due to degenerative disc disease, cervical spondylosis, or traumatic cervical spine injury. All our participants underwent surgical treatment, and complications were recorded. The most commonly performed procedure (79%) was anterior cervical discectomy and fusion (ACDF). Fourteen patients (12.3%) underwent anterior cervical corpectomy and interbody fusion, seven (6.1%) ACDF with plating, two (1.7%) odontoid screw fixation, and one anterior removal of osteophytes for severe Forestier's disease. Mean follow-up time was 42.5 months (range, 6-78 months). The overall complication rate was 13.2%. Specifically, we encountered adjacent intervertebral disc degeneration in 2.7% of our cases, dysphagia in 1.7%, postoperative soft tissue swelling and hematoma in 1.7%, and dural penetration in 1.7%. Additionally, esophageal perforation was observed in 0.9%, aggravation of preexisting myelopathy in 0.9%, symptomatic recurrent laryngeal nerve palsy in 0.9%, mechanical failure in 0.9%, and superficial wound infection in 0.9%. In the vast majority anterior cervical spine surgery-associated complications are minor, requiring no further intervention. Awareness, early recognition, and appropriate management, are of paramount importance for improving the patients' overall functional outcome.

Fibroma of the tendon sheath of the long head of the biceps tendon

International Nuclear Information System (INIS)

Maeseneer, Michel de; Shahabpour, Maryam; Isacker, Tom van; Lenchik, Leon; Caillie, Marie-Astrid van

2014-01-01

Fibroma of the tendon sheath is a benign tumor that is less common than giant cell tumor of the tendon sheath. Both tumors may present as a painless, slowly enlarging mass. Radiological findings may be similar for both tumors. Histologically, fibroma of the tendon sheath lacks the hemosiderin-laden macrophages that are typical for giant cell tumor of the tendon sheath. We report on a 49-year-old woman with fibroma of the tendon sheath of the long head of the biceps tendon. In our case, on MR images, we observed band-like hypointense areas centrally in the tumor, mild patchy contrast enhancement, and most importantly, no decrease of signal intensity on gradient echo images. These characteristics reflected histological findings. (orig.)

Tuberculosis of the cervical spine

African Journals Online (AJOL)

Tuberculosis of the cervical spine is rare, comprising 3 -. 5% of cases of tuberculosis of the spine. Eight patients with tuberculosis of the cervicaJ spine seen during 1989 -. 1992 were reviewed. They all presented with neck pain. The 4 children presented with a kyphotic deformity. In all the children the disease was extensive, ...

Imaging the Traumatized Spine'Clearing The Cervical Spine'

International Nuclear Information System (INIS)

Monu, U.V.J.

2015-01-01

Failure to recognize and diagnose injury to the cervical spine on plain radiographs can lead to severe and devastating consequences to the patient in particular and to the radiologist financially and otherwise. CT examination of the cervical spine aids and significantly improves diagnoses in many instances. it is neither economically feasible nor desirable to obtain CT on all patients. Meticulous attention to detail and zero tolerance for deviations from the usual radiographic landmarks will help select cases that should obtain additional imaging in form of CT or MRI scans. Faced with a task of clearing a cervical spine, a number of options are available. The first discriminator is whether or not the patient can be cleared clinically. If that is not possible, radiographic evaluation is needed. Strict adherence to a minimum three view plain radiograph for C-spine series must be maintained. Deviation from established norms for cervical spine radiographs should trigger a CT for additional evaluation

Tuberculosis of the Subaxial cervical spine: a case series from Tema, Ghana.

Science.gov (United States)

Andrews, N B

2010-01-01

Tuberculosis (TB) is endemic in West Africa. However, TB of the cervical spine is rare. To report a series of patients with TB of the sub-axial cervical spine (SACS), in order to illustrate its presentation, treatment and outcome. The patients were studied with respect to clinical history and physical examination. Laboratory tests, plain cervical spine X ray studies and myelography with post-myelographic CT scans were used for diagnosis. All patients underwent surgery and antituberculous therapy (ATT). Histopathologic results of surgical specimens were also analysed. All the patients were male and presented with severe neck pain and long tract signs. Osteomyelitis of the SACS was evident with disc space involvement and prevertebral soft tissue swelling. None of the patients had a history of pulmonary TB or TB meningitis; none had a positive Mantoux test. All patients improved neurologically after surgery and ATT. Although tuberculosis of the cervical spine is rare, the possibility of the disease should be considered when patients from areas in which the disease is endemic report with severe neck pain. Surgery could be indicated in cases with associated neurologic deficit and or spinal column instability. Anti-tuberculosis therapy should be continued for at least six months.

The electrostatic cylindrical sheath in a plasma

International Nuclear Information System (INIS)

Wang Chunhua; Sun Xiaoxia; Bai Dongxue

2004-01-01

The electrostatic sheath with a cylindrical geometry in an ion-electron plasma is investigated. Assuming a Boltzmann response to electrons and cold ions with bulk flow, it is shown that the radius of the cylindrical geometry do not affect the sheath potential significantly. The authors also found that the sheath potential profile is steeper in the cylindrical sheath compared to the slab sheath. The distinct feature of the cylindrical sheath is that the ion density distribution is not monotonous. The sheath region can be divided into three regions, two ascendant regions and one descendant region. (author)

Epithelioid hemangioendothelioma of the spine. Report of two cases.

LENUS (Irish Health Repository)

Aquilina, Kristian

2012-02-03

Epithelioid hemangioendothelioma (EH) is a rare tumor of vascular origin. The authors describe two cases of spinal EH, one involving the T-10 vertebra and the second involving the upper cervical spine. In the first case the patient underwent resection of the tumor; this case represents the longest reported follow-up period for spinal EH. In the second case, extensive involvement of C-2, C-3, and C-4 as well as encasement of both vertebral arteries precluded safe tumor resection, and posterior occipitocervical stabilization was performed. The patient subsequently died of metastatic disease. The findings in these two cases underscore the difficulty in predicting the clinical behavior of spinal EH based solely on histological and clinical features as well as the uncertainty of the roles of surgery, chemotherapy, and radiotherapy in the oncological management of a spinal tumor for which clinical data are very limited.

RF sheaths for arbitrary B field angles

Science.gov (United States)

D'Ippolito, Daniel; Myra, James

2014-10-01

RF sheaths occur in tokamaks when ICRF waves encounter conducting boundaries and accelerate electrons out of the plasma. Sheath effects reduce the efficiency of ICRF heating, cause RF-specific impurity influxes from the edge plasma, and increase the plasma-facing component damage. The rf sheath potential is sensitive to the angle between the B field and the wall, the ion mobility and the ion magnetization. Here, we obtain a numerical solution of the non-neutral rf sheath and magnetic pre-sheath equations (for arbitrary values of these parameters) and attempt to infer the parametric dependences of the Child-Langmuir law. This extends previous work on the magnetized, immobile ion regime. An important question is how the rf sheath voltage distributes itself between sheath and pre-sheath for various B field angles. This will show how generally previous estimates of the rf sheath voltage and capacitance were reasonable, and to improve the RF sheath BC. Work supported by US DOE grants DE-FC02-05ER54823 and DE-FG02-97ER54392.

Verification of high voltage rf capacitive sheath models with particle-in-cell simulations

Science.gov (United States)

Wang, Ying; Lieberman, Michael; Verboncoeur, John

2009-10-01

Collisionless and collisional high voltage rf capacitive sheath models were developed in the late 1980's [1]. Given the external parameters of a single-frequency capacitively coupled discharge, plasma parameters including sheath width, electron and ion temperature, plasma density, power, and ion bombarding energy can be estimated. One-dimensional electrostatic PIC codes XPDP1 [2] and OOPD1 [3] are used to investigate plasma behaviors within rf sheaths and bulk plasma. Electron-neutral collisions only are considered for collisionless sheaths, while ion-neutral collisions are taken into account for collisional sheaths. The collisionless sheath model is verified very well by PIC simulations for the rf current-driven and voltage-driven cases. Results will be reported for collisional sheaths also. [1] M. A. Lieberman, IEEE Trans. Plasma Sci. 16 (1988) 638; 17 (1989) 338 [2] J. P. Verboncoeur, M. V. Alves, V. Vahedi, and C. K. Birdsall, J. Comp. Phys. 104 (1993) 321 [3] J. P. Verboncoeur, A. B. Langdon and N. T. Gladd, Comp. Phys. Comm. 87 (1995) 199

On the upper bound in the Bohm sheath criterion

Energy Technology Data Exchange (ETDEWEB)

Kotelnikov, I. A., E-mail: I.A.Kotelnikov@inp.nsk.su; Skovorodin, D. I., E-mail: D.I.Skovorodin@inp.nsk.su [Russian Academy of Sciences, Budker Institute of Nuclear Physics, Siberian Branch (Russian Federation)

2016-02-15

The question is discussed about the existence of an upper bound in the Bohm sheath criterion, according to which the Debye sheath at the interface between plasma and a negatively charged electrode is stable only if the ion flow velocity in plasma exceeds the ion sound velocity. It is stated that, with an exception of some artificial ionization models, the Bohm sheath criterion is satisfied as an equality at the lower bound and the ion flow velocity is equal to the speed of sound. In the one-dimensional theory, a supersonic flow appears in an unrealistic model of a localized ion source the size of which is less than the Debye length; however, supersonic flows seem to be possible in the two- and three-dimensional cases. In the available numerical codes used to simulate charged particle sources with a plasma emitter, the presence of the upper bound in the Bohm sheath criterion is not supposed; however, the correspondence with experimental data is usually achieved if the ion flow velocity in plasma is close to the ion sound velocity.

Leiomyosarcoma, embrionary rhabdomyosarcoma and malignant peripheral nerve sheath tumor: report of three cases of atypical retroperitoneal sarcomas

International Nuclear Information System (INIS)

Catalan, Julian; Justino Junior, Reinaldo Ottero; Tjioe Tjia Min; Lima, Ana Carolina Mori; Fonte, Alexandre Calabria da; Goncalves, Carlos Marcelo

2005-01-01

We report three cases of atypical retroperitoneal sarcomas: leiomyosarcoma, embrionary rhabdomyosarcoma and malignant peripheral nerve sheath tumor (previously known as neuro sarcoma and neuro fibrosarcoma). These lesions, which are characterized by large and heterogeneous retroperitoneal masses, are uncommon and usually diagnosed late. Intravenous contrast enhanced computerized tomography is a useful method for the evaluation of these tumors and their relationship with adjacent structures. (author)

Gunshot injuries of the spine - a review of 49 cases managed at the ...

African Journals Online (AJOL)

The spinal injury was complete in 38 and incomplete in 8, with 3 having no neurological deficit. The level was cervical in 13, thoracic in 24 and lumbar in 12. Only 9 patients improved neurologically. The spine was considered stable in 43 cases. Stabilisation was performed in the 6 unstable cases. The bullets were removed ...

Long-term progress of six cases of malignant peripheral nerve sheath tumors of the mediastinum that underwent surgical treatment: Case report series

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Yuki Nakajima

2016-01-01

Discussion and conclusions: Nerve sheath tumors localized within the membrane offer good long-term prognosis even if malignant. Furthermore, long-term survival is possible even if the tumor has invaded neighboring organs, provided it can be completely excised. In cases where complete excision is difficult, a multidisciplinary approach including radiotherapy and anti-cancer drug treatment may contribute to improved prognosis but this is a subject that requires further study.

Tendon sheath fibroma in the thigh.

Science.gov (United States)

Moretti, Vincent M; Ashana, Adedayo O; de la Cruz, Michael; Lackman, Richard D

2012-04-01

Tendon sheath fibromas are rare, benign soft tissue tumors that are predominantly found in the fingers, hands, and wrists of young adult men. This article describes a tendon sheath fibroma that developed in the thigh of a 70-year-old man, the only known tendon sheath fibroma to form in this location. Similar to tendon sheath fibromas that develop elsewhere, our patient's lesion presented as a painless, slow-growing soft tissue nodule. Physical examination revealed a firm, nontender mass with no other associated signs or symptoms. Although the imaging appearance of tendon sheath fibromas varies, our patient's lesion appeared dark on T1- and bright on T2-weighted magnetic resonance imaging. It was well marginated and enhanced with contrast.Histologically, tendon sheath fibromas are composed of dense fibrocollagenous stromas with scattered spindle-shaped fibroblasts and narrow slit-like vascular spaces. Most tendon sheath fibromas can be successfully removed by marginal excision, although 24% of lesions recur. No lesions have metastasized. Our patient's tendon sheath fibroma was removed by marginal excision, and the patient remained disease free 35 months postoperatively. Despite its rarity, tendon sheath fibroma should be included in the differential diagnosis of a thigh mass on physical examination or imaging, especially if it is painless, nontender, benign appearing, and present in men. Copyright 2012, SLACK Incorporated.

Influence of vacuum space on formation of potential sheath in plasmas

International Nuclear Information System (INIS)

Uhm, H.S.

1997-01-01

Properties of potential sheaths developed in plasmas are investigated in terms of the plasma Debye length and the dimension of vacuum space. Biased plasma potential and the potential profile depend very sensitively on the geometrical configuration of plasma and vacuum space. The potential sheath is never developed near electrodes in high-density plasmas where the Debye length is much less than the dimension of the vacuum space. In this case, most of the potential drops occur in the vacuum space and almost no electric field exists inside the plasma. Parametric investigation of the potential sheath in terms of the vacuum-space and plasma dimensions is carried out. (orig.)

Cervical Spine Involvement as Initial Manifestation of Rheumatoid Arthritis: a case report

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Filipe Araújo

2015-01-01

Full Text Available Rheumatoid arthritis’ synovitis affects mostly small hand and feet joints, although it may compromise any joint with a synovial lining. Cervical involvement occurs usually in longstanding disease in over half of these patients. We report the case of a 35-year old male patient who was referred to our outpatient clinic for a 2-year severe and disabling inflammatory neck pain, with incomplete response to intramuscular non-steroidal anti-inflammatory drugs and unremarkable cervical imaging studies. He also mentioned self-limited episodes of symmetric polyarthralgia involving hands, wrists, elbows, knees and feet, which started after his cervical complaints. On laboratorial workup, positive rheumatoid factor and anti-citrullinated peptide antibody and negative HLA-B27 were found. Cervical spine magnetic resonance imaging revealed atlantoaxial subluxation and odontoid process inflammatory pannus and erosions. Rheumatoid arthritis with cervical spine involvement as initial manifestation of disease was the definite diagnosis. The patient was started on methotrexate and prednisone and he was referred to neurosurgery outpatient clinic for cervical spine fixation.

A clinical case study of long-term injury of the thoracic and lumbar spine

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Vladimir V Zaretskov

2016-06-01

Full Text Available Overestimation of the efficacy of conservative treatment of spine injuries children often leads to unsatisfactory long-term results. The effective correction of post-traumatic spinal column deformities occurs in patients who undergo the operation in the early post-traumatic period. While choosing treatment strategies for children, higher reparative opportunities, which provide early fracture consolidation, including those in faulty positions, should be considered. This study presents a case of surgical treatment for uncomplicated injury of the thoracic and lumbar spine, with long-term compression fragmental fracture of the L1 vertebra body in a 12-year-old child. Due to the long-standing character of the injury right thoraco-frenotomy was conducted with partial L1 vertebral body and resection of the adjacent discs, deformity correction of the thoracic and lumbar spine with a transpedicular system, and ventral spondylodesis with an autograft. This extensive intervention was justified by the peculiarities in the vertebral body damage and the post-traumatic segmental kyphotic deformity that resulted from delayed medical treatment. An anterior approach was chosen to achieve immobilization at the site of the damage before correction using the transpedicular system. Surgical correction of long-term spinal injuries in children, with the use of a combined approach, is usually laborious and traumatic. The prevention of rigid post-traumatic spine deformities with the help of timely diagnostics and appropriate treatment, including surgery, should be a priority to prevent such cases.

Anomalous Capacitive Sheath with Deep Radio Frequency Electric Field Penetration

International Nuclear Information System (INIS)

Kaganovich, Igor D.

2002-01-01

A novel nonlinear effect of anomalously deep penetration of an external radio-frequency electric field into a plasma is described. A self-consistent kinetic treatment reveals a transition region between the sheath and the plasma. Because of the electron velocity modulation in the sheath, bunches in the energetic electron density are formed in the transition region adjusted to the sheath. The width of the region is of order V(subscript T)/omega, where V(subscript T) is the electron thermal velocity, and w is frequency of the electric field. The presence of the electric field in the transition region results in a cooling of the energetic electrons and an additional heating of the cold electrons in comparison with the case when the transition region is neglected

A case of myositis ossificans in the upper cervical spine of a young child.

Science.gov (United States)

Findlay, Iain; Lakkireddi, Prabhat Reddy; Gangone, Ravinder; Marsh, Gavin

2010-12-01

Case report. We present a case of myositis ossificans (MO) of the upper cervical spine in a young child. The literature is reviewed with the classification, etiology, and treatment of MO discussed. Calcification of joint capsule, muscle, cartilage, and ligaments is a well-known phenomenon and is known as myositis ossificans. It is very rarely seen in the head and neck, with no reports of MO of the soft tissues surrounding the first 2 cervical vertebrae. An 8-year-old boy presented with severe neck pain after a fall. He had had a similar neck injury 4 years before, but made a full recovery. Radiographs showed a large ossified lesion between the posterior elements of C1 and C2. After further imaging, a diagnosis of MO was made. The child was treated with simple analgesia and observation. With no evidence of neurologic compromise and minimal symptoms, there was no indication for surgical intervention. Although rare, MO should be suspected as one of the possible causes of persistent pain following cervical spine injury in children. We would advise a low threshold for cervical spine imaging in the child presenting with persistent neck pain and stiffness, even years after injury.

Gorham's disease of the spine

International Nuclear Information System (INIS)

Livesley, P.J.; Saifuddin, A.; Webb, P.J.; Mitchell, N.; Ramani, P.

1996-01-01

Massive osteolysis is a rare condition and is very uncommon in the spine. The MRI appearance of Gorham's disease of the spine has not previously been reported. We present here a case of this condition with imaging details. (orig.)

Neuroimaging for spine and spinal cord surgery

Energy Technology Data Exchange (ETDEWEB)

Koyanagi, Izumi [Hokkaido Neurosurgical Memorial Hospital (Japan); Iwasaki, Yoshinobu; Hida, Kazutoshi

2001-01-01

Recent advances in neuroimaging of the spine and spinal cord are described based upon our clinical experiences with spinal disorders. Preoperative neuroradiological examinations, including magnetic resonance (MR) imaging and computerized tomography (CT) with three-dimensional reconstruction (3D-CT), were retrospectively analyzed in patients with cervical spondylosis or ossification of the posterior longitudinal ligament (130 cases), spinal trauma (43 cases) and intramedullary spinal cord tumors (92 cases). CT scan and 3D-CT were useful in elucidating the spine pathology associated with degenerative and traumatic spine diseases. Visualization of the deformity of the spine or fracture-dislocation of the spinal column with 3D-CT helped to determine the correct surgical treatment. MR imaging was most important in the diagnosis of both spine and spinal cord abnormalities. The axial MR images of the spinal cord were essential in understanding the laterality of the spinal cord compression in spinal column disorders and in determining surgical approaches to the intramedullary lesions. Although non-invasive diagnostic modalities such as MR imaging and CT scans are adequate for deciding which surgical treatment to use in the majority of spine and spinal cord disorders, conventional myelography is still needed in the diagnosis of nerve root compression in some cases of cervical spondylosis. (author)

Spontaneous Rectus Sheath Hematoma in the Elderly: An Unusual Case and Update on Proper Management

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George Galyfos

2014-01-01

Full Text Available Spontaneous rectus sheath hematoma (SRSH is an uncommon medical emergency in the elderly. We present a case of SRSH with an atypical clinical presentation and discuss literature regarding diagnosis and proper management. A 75-year-old female patient was transferred to the emergency department due to acute dyspnoea and confusion. Her medical history revealed a viral infection of the upper respiratory tract, and no coughing or use of anticoagulants. The clinical examination showed tenderness of the left lower abdomen, although palpation was misleading due to patient’s obesity. Laboratory investigations showed light anaemia. Ultrasonography and computed tomography revealed a large rectus sheath hematoma of the left abdominal wall. Despite further deterioration of the patient, conservative management including bed rest, fluid replacement, blood products transfusion, and proper analgesia was successful. No surgical intervention was needed. Prompt diagnosis and management of SRSH plays significant role in the prognosis, especially in elder patients. Independently of size and severity, conservative management remains the first therapeutic choice. Only by failure of supportive management, progressive and large hematoma or uncontrollable hemodynamic patients, interventional management including surgery or less invasive newer techniques is indicated.

Desmoid type fibromatosis in the facet joint of lumbar spine: Case report and review of literature

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Kim, So Jung; Ha, Doo Hoe; Lee, Sang Min; Kang, Hae Youn [CHA Bundang Medical Center, CHA University, Seongnam (Korea, Republic of)

2013-10-15

Desmoid type fibromatosis is a benign fibroblastic tumor arising from the fascia or musculoaponeurosis. It may occur in various locations, but most commonly in the shoulder girdle and neck; to our knowledge, there has been no reported case originating from a facet joint of the spine. We report CT and MR imaging findings of a desmoid type fibromatosis, involving the facet joint of the L3-4 spine with bone involvement.

Subarachnoid hematoma of the craniocervical junction and upper cervical spine after traumatic cerebral contusion: case report.

Science.gov (United States)

Di Rienzo, Alessandro; Iacoangeli, Maurizio; Alvaro, Lorenzo; Colasanti, Roberto; Moriconi, Elisa; Gladi, Maurizio; Nocchi, Niccolò; Scerrati, Massimo

2013-01-01

Spinal subarachnoid hematoma (SSH) is a rare condition, more commonly occurring after lumbar puncture for diagnostic or anesthesiological procedures. It has also been observed after traumatic events, in patients under anticoagulation therapy or in case of arteriovenous malformation rupture. In a very small number of cases no causative agent can be identified and a diagnosis of spontaneous SSH is established. The lumbar and thoracic spine are the most frequently involved segments and only seven cases of cervical spine SSH have been described until now. Differential diagnosis between subdural and subarachnoid hematoma is complex because the common neuroradiological investigations, including a magnetic resonance imaging (MRI), are not enough sensitive to exactly define clot location. Actually, confirmation of the subarachnoid location of bleeding is obtained at surgery, which is necessary to resolve the fast and sometimes dramatic evolution of clinical symptoms. Nonetheless, there are occasional reports on successful conservative treatment of these lesions. We present a peculiar case of subarachnoid hematoma of the craniocervical junction, developing after the rupture of a right temporal lobe contusion within the adjacent arachnoidal spaces and the following clot migration along the right lateral aspect of the foramen magnum and the upper cervical spine, causing severe neurological impairment. After surgical removal of the hematoma, significant symptom improvement was observed.

Multimodal imaging in neurofibromatosis type 1-associated nerve sheath tumors

International Nuclear Information System (INIS)

Salamon, J.; Adam, G.; Mautner, V.F.; Derlin, T.

2015-01-01

Neurofibromatosis type 1 (NF1) is a neurogenetic disorder. Individuals with NF1 may develop a variety of benign and malignant tumors of which peripheral nerve sheath tumors represent the most frequent entity. Plexiform neurofibromas may demonstrate a locally destructive growth pattern, may cause severe symptoms and may undergo malignant transformation into malignant peripheral nerve sheath tumors (MPNSTs). Whole-body magnetic resonance imaging (MRI) represents the reference standard for detection of soft tissue tumors in NF1. It allows for identification of individuals with plexiform neurofibromas, for assessment of local tumor extent, and for evaluation of whole-body tumor burden on T2-weighted imaging. Multiparametric MRI may provide a comprehensive characterization of different tissue properties of peripheral nerve sheath tumors, and may identify parameters associated with malignant transformation. Due to the absence of any radiation exposure, whole-body MRI may be used for serial follow-up of individuals with plexiform neurofibromas. 18 F-fluorodeoxyglucose positron-emission-tomography (FDG PET/CT) allows a highly sensitive and specific detection of MPNST, and should be used in case of potential malignant transformation of a peripheral nerve sheath tumor. PET/CT provides a sensitive whole-body tumor staging. The use of contrast-enhanced CT for diagnosis of peripheral nerve sheath tumors is limited to special indications. To obtain the most precise readings, optimized examination protocols and dedicated radiologists and nuclear medicine physicians familiar with the complex and variable morphologies of peripheral nerve sheath tumors are required.

Eosinophilic granuloma of spine in adults: a report of 30 cases and outcome.

Science.gov (United States)

Huang, Wending; Yang, Xinghai; Cao, Dong; Xiao, Jianru; Yang, Mosong; Feng, Dapeng; Huang, Quan; Wu, Zhipeng; Zheng, Wei; Jia, Lianshun; Wu, Shujia

2010-07-01

Eosinophilic granuloma (EG) of the spine is rare, especially in adults. There had been few large and long-term studies reported in the literature. The management goals of this disease in adults are preservation of neurologic function, relief of pain and reconstruction of spinal stability. However, there are still controversies over appropriate management modality of eosinophilic granuloma. Clinical manifestations, radiographic presentations, therapeutic outcomes and follow-up findings of 30 adults who were histiologically diagnosed with spinal eosinophilic granuloma, including 28 patients who received surgical treatment at our institutions from 1985 to 2008 were reviewed retrospectively. There were 25 males and five females with a mean age of 34.5 years (range, 18-71 years). The post-operative follow-up period ranged from 2 to 22.4 years (mean, 8.3 years). Neurologic deficits developed in 21 patients, apparent kyphosis developed in four cases. In contrast to the classic feature of vertebra plana in children, we found that more severe lesions often led to asymmetric collapse in adult patients and only three patients presented with vertebra plana. Thirty-three vertebral lesions distributed throughout the spine column. Twenty-one lesions were in cervical spine, seven in the thoracic spine and five in the lumbar spine. Twenty-eight adult patients underwent surgical resection with or without chemotherapy or radiotherapy, and four (13.3%) patients had recurrence after surgery. No patient in our series died. The onset of spinal EG is insidious and mainly presents as osteolytic destruction. There is a particular high prevalence of lesions in the cervical spine and more severe lesions often led to asymmetric collapse. As the skeleton of adults is well-developed and the epiphysis has stopped growing, individualized management including surgical intervention should be considered in adult patients with spinal EG who present with neurological damage and spinal instability.

Magnetic sheath effect on the gross and net erosion rates due to impurities

Science.gov (United States)

Mellet, N.; Pégourié, B.; Martin, C.; Gunn, J. P.; Bufferand, H.; Roubin, P.

2016-02-01

Simulations of impurity trajectories in deuterium plasmas in the vicinity of the surface are performed by taking into account the magnetic sheath in conditions relevant for ITER and WEST. We show that the magnetic sheath has a strong effect on the average impact angle of impurities in divertor conditions and that it can lead to an increase of ≈ 60% at the gross erosion maximum for neon (Ne+4) compared to the case when only the cyclotron motion is considered. The evaluation of the net erosion has been undertaken by retaining local redeposition of tungsten (W). We investigate how it is affected by the sheath magnetic potential profile. The largest effect is however observed when an energy distribution is considered. In this case the number of particles that manage to exit the sheath is larger as it is dominated by the more energetic particles. The comparison with other work is also discussed. The application to a scenario of the WEST project is finally performed, which exhibits a moderate, however non negligible, erosion of the plasma facing components.

Ophaceous Gout Involving the Whole Spine: An Unusual Case Report

Energy Technology Data Exchange (ETDEWEB)

Shin, Min Woo; Lee, Ji Hae; Cho, Woo Ho [Dept. of Radiology, Sanggye Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of)

2012-02-15

Gout is a relatively common, crystal deposition disease, in which monosodium urate crystals are deposited in joint and periarticular tissues of the extremities. Involvement of the spine is exceedingly rare. Most patients with spinal gout present with symptomatic spinal cord compression. Diffuse involvement of tophi deposition inside the spinal central canal has not been reported. We now present a case of chronic tophaceous gout with extensive spinal involvement that resulted in diffuse spinal cord compression and led to paraplegia.

Ophaceous Gout Involving the Whole Spine: An Unusual Case Report

International Nuclear Information System (INIS)

Shin, Min Woo; Lee, Ji Hae; Cho, Woo Ho

2012-01-01

Gout is a relatively common, crystal deposition disease, in which monosodium urate crystals are deposited in joint and periarticular tissues of the extremities. Involvement of the spine is exceedingly rare. Most patients with spinal gout present with symptomatic spinal cord compression. Diffuse involvement of tophi deposition inside the spinal central canal has not been reported. We now present a case of chronic tophaceous gout with extensive spinal involvement that resulted in diffuse spinal cord compression and led to paraplegia.

Polyetheretherketone (PEEK) Rods in Lumbar Spine Degenerative Disease: A Case Series.

Science.gov (United States)

Ormond, D Ryan; Albert, Ladislau; Das, Kaushik

2016-08-01

Retrospective case series. The purpose of our study was to retrospectively review the results of posterior lumbar fusion using polyetheretherketone (PEEK) rods. Pedicle screw and rod instrumentation has become the preferred technique for performing stabilization and fusion in the lumbar spine for degenerative disease. Rigid fixation with titanium rods leads to high fusion rates, but may also contribute to stress shielding and adjacent segment degeneration (ASD). Thus, some have advocated using semirigid rods made of PEEK. Although the biomechanical properties of PEEK rods have shown improved stress-shielding characteristics and anterior load-sharing properties, there are very few clinical studies evaluating their application in the lumbar spine. We evaluated a retrospective cohort of 42 patients who underwent posterior lumbar fusion from 2007 to 2009 for the treatment of lumbar spine degenerative disease using PEEK rods. Reoperation rate was the primary outcome evaluated. Fusion rate was also evaluated. Eight of the 42 patients with PEEK rods required reoperation. Reasons for reoperation mainly included ASD (5/8) and nonunion with cage migration (3/8). Radiographically, documented fusion rate was 86%. Mean follow-up was 31.4 months. No statistical differences were found in fusion rates or reoperation between age above 55 years and younger than 55 years (P=1.00), male and female (P=0.110), single or multilevel fusion (P=0.67), and fusion with and without an interbody graft (P=0.69). Smokers showed a trend towards increased risk of reoperation for ASD or instrumentation failure (P=0.056). PEEK rods demonstrate a similar fusion and reoperation rate in comparison to other instrumentation modalities in the treatment of degenerative lumbar spine disease.

Langerhans-cell histiocytosis of the cervical spine in an adult patient: Case report and review of the literature.

Science.gov (United States)

Vielgut, Ines; Liegl-Atzwanger, Bernadette; Bratschitsch, Gerhard; Leithner, Andreas; Radl, Roman

2017-06-01

Langerhans-cell histiocytosis (LCH) is a rare, benign bone tumor, usually occurring in children and younger adults under 20 years old. Only a few cases of solitary bone lesions of the adult spine are reported in literature, therapeutic guidelines or treatment regimens for lesions of the adult spine are not established yet to our knowledge.

Use of a hot sheath Tormac for advance fuels

International Nuclear Information System (INIS)

Levine, M.A.

1977-01-01

The use of hot electrons in a Tormac sheath is predicted to improve stability and increase ntau by an order of magnitude. An effective ntau for energy containment is derived and system parameters for several advance fuels are shown. In none of the advance fuels cases considered is a reactor with fields greater than 10 Wb or major plasma radius of more than 3 m required for ignition. Minimum systems have power output of under 100 MW thermal. System parameters for a hot sheath Tormac have a wide latitude. Sizes, magnetic fields, operating temperatures can be chosen to optimize engineering and economic considerations

Three-dimensional analysis of antenna sheaths

International Nuclear Information System (INIS)

Myra, J.R.; D'Ippolito, D.A.; Ho, Y.L.

1996-01-01

The present work is motivated by the importance of r.f. sheaths in determining the antenna-plasma interaction and the sensitivity of the sheaths to the complicated three-dimensional structure of modern ion cyclotron range of frequency (ICRF) antennas. To analyze r.f. sheaths on the plasma facing regions of the launcher, we first calculate the contact points of the tokamak magnetic field lines on the surface of the antenna Faraday screen and nearby limiters for realistic three-dimensional magnetic flux surface and antenna geometries. Next, the r.f. voltage that can drive sheaths at the contact points is determined and used to assess the resulting sheath power dissipation, r.f.-driven sputtering, and r.f.-induced convective cells (which produce edge profile modification). The calculations are embodied in a computer code, ANSAT (antenna sheath analysis tool), and sample ANSAT runs are shown to highlight the physics- and geometry-dependent characteristics of the r.f. sheaths and their relationship to the antenna design. One use of ANSAT is therefore as a design tool, to assess the strengths and weaknesses of a given design with respect to critical voltage handling and edge plasma interaction issues. Additionally, examples are presented where ANSAT has been useful in the analysis and interpretation of ICRF experiments (orig.)

Surgical Management of Subaxial Cervical Spine Trauma: A Case Report

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Hasan Emre Aydın

2015-04-01

Full Text Available These days, as a consequence of the improvement in technology and increase in the use of motor vehicles, spine injuries have become common. Spine traumas, which often occur after motor vehicle accidents, are observed mostly in cervical regions, particularly in the subaxial cervical region, which is also known as the subcervical region, and neurological damage occurs in 70% of the patients. Despite still being controversial, the common ranging for neurological evaluation is the American Spinal Injury Association ranging, which includes the motor and sensory loss and accordingly, the impairment rate. In subaxial cervical traumas, acute neurological deterioration is an indication and therefore requires urgent surgical treatment. The choice of anterior or posterior approach substantially depends on the traumatization mechanism, affected tissues, and neurological deterioration occurring after. The state of patient and instability are the most two important factors affecting the treatment decision. Although the anterior approach is accepted as a routinely available and easily applicable surgical technique, it lacks in the burst fractures involving the three colons, which shows a stabilization disorder. The anterior plate screw technique and posterior lateral mass screw application applied in our clinic are reviewed in literature and are discussed in two cases. Although the best clinical results are achieved in cases where only anterior surgery is performed and in cases where instability is excessive, in unstable compression and blow-out fractures, even if neurological deficit and three colon involvement are not observed in the patient, the requirement of posterior fusion is observed.

A rare case of bilateral optic nerve sheath meningioma

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Somen Misra

2014-01-01

Full Text Available A 60-year-old female presented with gradual, painless, progressive diminution of vision, and progressive proptosis of left eye since 7 years. Ophthalmological examination revealed mild proptosis and total optic atrophy in the left eye. Magnetic resonance imaging (MRI and computed tomography (CT brain with orbit showed bilateral optic nerve sheath meningioma (ONSM involving the intracranial, intracanalicular, intraorbital part of the optic nerve extending up to optic chiasma and left cavernous sinus.

Barrier cell sheath formation

International Nuclear Information System (INIS)

Kesner, J.

1980-04-01

The solution for electrostatic potential within a simply modeled tandem mirror thermal barrier is seen to exhibit a sheath at each edge of the cell. The formation of the sheath requires ion collisionality and the analysis assmes that the collisional trapping rate into the barrier is considerably slower than the barrier pump rate

Method of calculating pilestrip foundations in case of karst hole formation

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Gotman Al'fred Leonidovich

2014-02-01

Full Text Available The paper presents pile strip foundations in the areas with karst risk. The analysis of karst hole formation mechanism shows the lateral soil pressure on the piles caused by the downfallen soil on the hole rims, which transfers around the hole edges during karst hole formation. In this case, the horizontal pressure of the pile reactive force in the area of the pile connection with the raft is transferred to the raft. Pile failure at the hole boundaries will lead to the increase of the raft bearing distance above the karst hole. The inadequate raft bearing capacity can provoke the emergency situation. The existing Codes on karst protective foundations design do not contain the analysis of pile and raft horizontal pressure under the downfallen soil.The goal of this work is to develop the method of pile strip foundations analysis in the areas with karst risk in case of karst hole formation. The analysis of stress-strain state of the system “foundation soil — pile foundation” was carried out using numerical modeling in geotechnical program MIDAS GTS. As a result of numerical investigations, the diagrams of lateral soil pressure onto the piles and the raft are plotted. The pile pressure is approximated with the linear or bilinear function in dependence on geometrical dimensions of the karst hole and strength characteristics of soil that generates the horizontal pressure.In the Codes, the analysis of a pile under lateral soil pressure is given for a pile with the free end. In the problem examined, the pile head has the hinged bearing in place of the connection with the raft. In view of the given boundary data, the pile design scheme is plotted. The inner forces and displacements of the pile are determined by integrating the differential equation of a pile bending. The consistent integrations are evaluated out of the boundary conditions. The boundary values of inner forces and displacements are evaluated from the equality conditions of

Co-electrospinning fabrication and photocatalytic performance of TiO2/SiO2 core/sheath nanofibers with tunable sheath thickness

International Nuclear Information System (INIS)

Cao, Houbao; Du, Pingfan; Song, Lixin; Xiong, Jie; Yang, Junjie; Xing, Tonghai; Liu, Xin; Wu, Rongrong; Wang, Minchao; Shao, Xiaoli

2013-01-01

Graphical abstract: - Highlights: • The core–sheath TiO 2 /SiO 2 nanofibers were fabricated by co-electrospinning technique. • The catalytic property of nanofibers with different sheath thickness was studied. • The potential methods of improving catalytic efficiency are suggested. - Abstract: In this paper, core/sheath TiO 2 /SiO 2 nanofibers with tunable sheath thickness were directly fabricated via a facile co-electrospinning technique with subsequent calcination at 500 °C. The morphologies and structures of core/sheath TiO 2 /SiO 2 nanofibers were characterized by TGA, FESEM, TEM, FTIR, XPS and BET. It was found that the 1D core/sheath nanofibers are made up of anatase–rutile TiO 2 core and amorphous SiO 2 sheath. The influences of SiO 2 sheath and its thickness on the photoreactivity were evaluated by observing photo-degradation of methylene blue aqueous solution under the irradiation of UV light. Compared with pure TiO 2 nanofibers, the core/sheath TiO 2 /SiO 2 nanofibers performed a better catalytic performance. That was attributed to not only efficient separation of hole–electron pairs resulting from the formation of heterojunction but also larger surface area and surface silanol group which will be useful to provide higher capacity for oxygen adsorption to generate more hydroxyl radicals. And the optimized core/sheath TiO 2 /SiO 2 nanofibers with a sheath thickness of 37 nm exhibited the best photocatalytic performance

Primary bony non-Hodgkin lymphoma of the cervical spine: a case report

Directory of Open Access Journals (Sweden)

Sedrak Mark F

2010-02-01

Full Text Available Abstract Introduction Non-Hodgkin lymphoma primarily originating from the bone is exceedingly rare. To our knowledge, this is the first report of primary bone lymphoma presenting with progressive cord compression from an origin in the cervical spine. Herein, we discuss the unusual location in this case, the presenting symptoms, and the management of this disease. Case presentation We report on a 23-year-old Caucasian-American man who presented with two months of night sweats, fatigue, parasthesias, and progressive weakness that had progressed to near quadriplegia. Magnetic resonance (MR imaging demonstrated significant cord compression seen primarily at C7. Surgical management, with corpectomy and dorsal segmental fusion, in combination with adjuvant chemotherapy and radiation therapy, halted the progression of the primary disease and preserved neurological function. Histological analysis demonstrated an aggressive anaplastic large cell lymphoma. Conclusion Isolated primary bony lymphoma of the spine is exceedingly rare. As in our case, the initial symptoms may be the result of progressive cervical cord compression. Anterior corpectomy with posterolateral decompression and fusion succeeded in preventing progressive neurologic decline and maintaining quality of life. The reader should be aware of the unique presentation of this disease and that surgical management is a successful treatment strategy.

Imaging in a case of giant cell tumor of tendon sheath in foot: A case report with re-view of literature

Directory of Open Access Journals (Sweden)

Sujata Patnaik

2014-07-01

Full Text Available Large sized Giant cell tumors (GCT of the tendon sheaths of the foot are rare. We present a case with a large tumor over the dor-sum of foot which was diagnosed and studied by plain radiog-raphy, Ultrasound, CT and MRI scans. It was histologically con-firmed on biopsy. When the size of the tumor (like Giant cell tu-mor is too large and spread over multiple bones of the foot MRI is the imaging modality of choice to precisely define the anatomy to help in taking surgical decisions.

Radio frequency sheaths in an oblique magnetic field

International Nuclear Information System (INIS)

Myra, J. R.; D'Ippolito, D. A.

2015-01-01

The physics of radio-frequency (rf) sheaths near a conducting surface is studied for plasmas immersed in a magnetic field that makes an oblique angle θ with the surface. A set of one-dimensional equations is developed that describes the dynamics of the time-dependent magnetic presheath and non-neutral Debye sheath. The model employs Maxwell-Boltzmann electrons, and the magnetization and mobility of the ions is determined by the magnetic field strength, and wave frequency, respectively. The angle θ, assumed to be large enough to insure an electron-poor sheath, is otherwise arbitrary. Concentrating on the ion-cyclotron range of frequencies, the equations are solved numerically to obtain the rectified (dc) voltage, the rf voltage across the sheath, and the rf current flowing through the sheath. As an application of this model, the sheath voltage-current relation is used to obtain the rf sheath impedance, which in turn gives an rf sheath boundary condition for the electric field at the sheath-plasma interface that can be used in rf wave codes. In general, the impedance has both resistive and capacitive contributions, and generalizes previous sheath boundary condition models. The resistive part contributes to parasitic power dissipation at the wall

Sheath waves, non collisional dampings

International Nuclear Information System (INIS)

Marec, Jean Lucien Ernest

1974-01-01

When a metallic conductor is inserted into an ionised gas, an area of electron depletion is formed between the conductor and the plasma: the ionic sheath. Moreover, if the conductor is excited by an electric field, this ionic sheath plays an important role with respect to microwave properties. In this research thesis, the author addresses the range of frequencies smaller than the plasma frequency, and reports the study of resonance phenomena. After a presentation of the problem through a bibliographical study, the author recalls general characteristics of sheath wave propagation and of sheath resonances, and discusses the validity of different hypotheses (for example and among others, electrostatic approximations, cold plasma). Then, the author more particularly addresses theoretical problems related to non collisional dampings: brief bibliographical study, detailed presentation and description of the theoretical model, damping calculation methods. The author then justifies the design and performance of an experiment, indicates measurement methods used to determine plasma characteristics as well as other magnitudes which allow the description of mechanisms of propagation and damping of sheath waves. Experimental results are finally presented with respect to various parameters. The author discusses to which extent the chosen theoretical model is satisfying [fr

Management of neglected cervical spine dislocation: a study of six cases

Directory of Open Access Journals (Sweden)

Goni Vijay

2013-08-01

Full Text Available 【Abstract】Objective: To report a case series of six neglected cervical spine dislocations without neurological deficit, which were managed operatively. Methods: The study was conducted from August 2010 to December 2011 and cases were selected from the out-patient department of Postgraduate Institute of Medical Education and Research, India. The patients were in the age group of 30 to 50 years. All patients were operated via both anterior and posterior approaches. Results: During the immediate postoperative period, five (83.33% patients had normal neurological status. One (16.67% patient who had C 5 -C 6 subluxation developed neu-rological deficit with sensory loss below C 6 level and motor power of 2/5 in the lower limb and 3/5 in the upper limb below C 6 level. Conclusion: There is no role of skull traction in ne-glected distractive flexion injuries to cervical spine delayed for more than 3 weeks. Posterior followed by anterior ap-proach saves much time. If both approaches are to be done in the same sitting, there is no need for instrumentation posteriorly. But if staged procedure is planed, posterior sta-bilization is recommended, as there is a risk of deterioration in neurological status. Key words: Cervical vertebrae; Neck; Postoperative complications

Optic nerve sheath meningioma treated with radiation conformal therapy. Clinical case report with long follow up

International Nuclear Information System (INIS)

Zomosa R, Gustavo; Cruz T, Sebastian; Miranda G, Gonzalo; Harbst S, Hans

2016-01-01

Optic nerve sheath meningiomas (ONSM) are rare tumors of the anterior visual pathway. Without treatment, tumor growth leads to progressive loss of visual acuity and blindness due to optic nerve compression. Case report: Patient, female, 42 years without other morbility , begins in 1992 with decreased visual acuity of the left eye, magnetic resonance imaging (MRI) showed enlargement of the left optic nerve sheath, suggestive of ONSM. On that occasion, orbit exploration failed, so it was decided to follow up with annual clinical and imaging controls. About ten years later, begins with progressive deterioration of visual acuity and visual field , with ptosis and ocular motor palsy of the left eye, confirmed with neuro-ophthalmological examinations. MRI shows tumor progression. A new surgical approach was discarded by the risk of visual worsening. A conformal radiotherapy was performed with a fractionated 54 Gy dose. Today, at age 65, after 24 years of follow up,13 post radiation therapy. clinical and radiological stability of ONSM is confirmed. Discussion: Conformal radiotherapy has been shown as an effective therapy, with fewer complications and better outcomes in the preservation of visual function in the long term follow up Radio-fluoro guided surgery in high grade gliomas

Ion acceleration in the plasma source sheath

International Nuclear Information System (INIS)

Birdsall, C.K.

1986-01-01

This note is a calculation of the potential drop for a planar plasma source, across the source sheath, into a uniform plasma region defined by vector E = 0 and/or perhaps ∂ 2 PHI/∂ x 2 = 0. The calculation complements that of Bohm who obtained the potential drop at the other end of a plasma, at a planar collector sheath. The result is a relation between the source ion flux and the source sheath potential drop and the accompanying ion acceleration. This planar source sheath ion acceleration mechanism (or that from a distributed source) can provide the pre-collector-sheath ion acceleration as found necessary by Bohm. 3 refs

Self-consistent radial sheath

International Nuclear Information System (INIS)

Hazeltine, R.D.

1988-12-01

The boundary layer arising in the radial vicinity of a tokamak limiter is examined, with special reference to the TEXT tokamak. It is shown that sheath structure depends upon the self-consistent effects of ion guiding-center orbit modification, as well as the radial variation of E /times/ B-induced toroidal rotation. Reasonable agreement with experiment is obtained from an idealized model which, however simplified, preserves such self-consistent effects. It is argued that the radial sheath, which occurs whenever confining magnetic field-lines lie in the plasma boundary surface, is an object of some intrinsic interest. It differs from the more familiar axial sheath because magnetized charges respond very differently to parallel and perpendicular electric fields. 11 refs., 1 fig

Ion clusters, REB, and current sheath characteristics in focused discharges

International Nuclear Information System (INIS)

Bortolotti, A.; Brzosko, J.; DeChiara, P.; Kilic, H.; Mezzetti, F.; Nardi, V.; Powell, C.; Zeng, D.

1990-01-01

Small fluctuations in the current sheath characteristics (peak current density, FWHM of leading sheath, control parameters of sheath internal structure) are linked to wide fluctuations of ion and ion cluster emission from the pinch. Magnetic probe data are used for correlating variations of current sheath parameters with particle emission intensity, Z/M composition, particle energy spectrum. The emission of ion and ion clusters at 90 degrees from the axis of a plasma focus discharge is monitored simultaneously with the 0 degrees emission. The particle energy spectrum is analyzed with a Thomson (parabola) spectrometer (time resolution ∼ 1 nanosec). The cross-sectional structure of the REB at 180 degrees along the discharge axis is monitored via the deposition of collective-field accelerated ions on a target in the REB direction. Etched tracks of ion and ion clusters are in all cases recorded on CR-39 plates. Sharp peaks of the D + -ion spectrum at 90 degrees are found for E > 200 keV/unit charge in all focused discharges. These peaks are due to ion crossing of the azimuthal magnetic field of the pinch region, in a predominant ion cluster structure

Tertiary syphilis in the lumbar spine: a case report.

Science.gov (United States)

Bai, Yang; Niu, Feng; Liu, Lidi; Sha, Hui; Wang, Yimei; Zhao, Song

2017-07-24

The incidence of tertiary syphilis involvement in the spinal column with destructive bone lesions is very rare. It is difficult to establish the correct diagnosis from radiographs and histological examination alone. Limited data are available on surgical treatment to tertiary syphilitic spinal lesions. In this article, we report a case of tertiary syphilis in the lumbar spine with osteolytic lesions causing cauda equina compression. A 44-year-old man who suffered with low back pain for 6 months and progressive radiating pain at lower extremity for 1 week. Radiologic findings showed osteolytic lesion and new bone formation in the parts of the bodies of L4 and L5. Serum treponema pallidum hemagglutination (TPHA) test was positive. A surgery of posterior debridement, interbody and posterolateral allograft bone fusion with instrumentation from L3 to S1 was performed. The low back pain and numbness abated after operation. But the follow-up radiographs showed absorption of the bone grafts and failure of instrumentation. A Charcot's arthropathy was formed between L4 and L5. It is challenging to diagnose the tertiary syphilis in the spine. Surgery is a reasonable auxiliary method to antibiotic therapy for patients who suffered with neuropathy. Charcot's arthropathy should be considered as an operative complication.

Brachial Plexopathy After Cervical Spine Surgery

OpenAIRE

Than, Khoi D.; Mummaneni, Praveen V.; Smith, Zachary A.; Hsu, Wellington K.; Arnold, Paul M.; Fehlings, Michael G.; Mroz, Thomas E.; Riew, K. Daniel

2017-01-01

Study Design: Retrospective, multicenter case-series study and literature review. Objectives: To determine the prevalence of brachial plexopathy after cervical spine surgery and to review the literature to better understand the etiology and risk factors of brachial plexopathy after cervical spine surgery. Methods: A retrospective case-series study of 12?903 patients at 21 different sites was performed to analyze the prevalence of several different complications, including brachial plexopathy....

Genetic instability in nerve sheath cell tumors

DEFF Research Database (Denmark)

Rogatto, Silvia Regina; Casartelli, Cacilda; Rainho, Claudia Aparecida

1995-01-01

After in vitro culture, we analyzed cytogenetically four acoustic nerve neurinomas, one intraspinal neurinoma and one neurofibroma obtainedfrom unrelated patients. Monosomy of chromosomes 22 and 16 was an abnormality common to all cases, followed in frequency by loss of chromosomes 18 (three cases...... by the presence of polyploid cells with inconsistent abnormalities, endoreduplications and telomeric associations resulting in dicentric chromosomes. It is probable that these cytogenetic abnormalities represent some kind of evolutionary advantage for the in vitro progression of nerve sheath tumors....

Effects of an anode sheath on energy and momentum transfer in vacuum arcs

International Nuclear Information System (INIS)

Wang, Zhenxing; Zhou, Zhipeng; Tian, Yunbo; Wang, Haoran; Wang, Jianhua; Geng, Yingsan; Liu, Zhiyuan

2017-01-01

Anode phenomena under high-current vacuum arcs have a significant impact on the interrupting capacity of vacuum interrupters. However, the vacuum arc energy flux and momentum flux on the anode—which are necessary boundary conditions for simulations—are either set to an imaginary distribution or calculated using simple formulas without considering anode sheath regulatory effects. The objective of this paper is to reveal the anode sheath effects on regulating the energy and momentum transfer from the arc column to the anode surface in vacuum arcs. A particle-in-cell model for the anode sheath is developed. The required input parameters are obtained from a magnetohydrodynamic model for the arc column. From the results, there exists a sheath near the anode with a negative voltage drop. Both the electron density and the ion density significantly decline in the anode sheath region. The kinetic energy of the ions absorbed by the anode consists of directed kinetic energy, random kinetic energy, and sheath acceleration energy. The sheath acceleration energy contribution is the largest, and the random kinetic energy also accounts for a large part that cannot be ignored. The arc pressure on the anode surface is mainly caused by ion impact, and the accelerating effect of the anode sheath on the ions cannot be neglected in pressure calculations. In addition, in the case of an arc current at 15 kA, the input energy and momentum upon the anode surface is not obviously affected by the evaporated atoms at surface temperatures of 1600 K and 2000 K. (paper)

Sheath insulator final test report, TFE Verification Program

Energy Technology Data Exchange (ETDEWEB)

1994-07-01

The sheath insulator in a thermionic cell has two functions. First, the sheath insulator must electrically isolate the collector form the outer containment sheath tube that is in contact with the reactor liquid metal coolant. Second, The sheath insulator must provide for high uniform thermal conductance between the collector and the reactor coolant to remove away waste heat. The goals of the sheath insulator test program were to demonstrate that suitable ceramic materials and fabrication processes were available, and to validate the performance of the sheath insulator for TFE-VP requirements. This report discusses the objectives of the test program, fabrication development, ex-reactor test program, in-reactor test program, and the insulator seal specifications.

Sheath insulator final test report, TFE Verification Program

International Nuclear Information System (INIS)

1994-07-01

The sheath insulator in a thermionic cell has two functions. First, the sheath insulator must electrically isolate the collector form the outer containment sheath tube that is in contact with the reactor liquid metal coolant. Second, The sheath insulator must provide for high uniform thermal conductance between the collector and the reactor coolant to remove away waste heat. The goals of the sheath insulator test program were to demonstrate that suitable ceramic materials and fabrication processes were available, and to validate the performance of the sheath insulator for TFE-VP requirements. This report discusses the objectives of the test program, fabrication development, ex-reactor test program, in-reactor test program, and the insulator seal specifications

Plasma sheath criterion in thermal electronegative plasmas

International Nuclear Information System (INIS)

Ghomi, Hamid; Khoramabadi, Mansour; Ghorannevis, Mahmod; Shukla, Padma Kant

2010-01-01

The sheath formation criterion in electronegative plasma is examined. By using a multifluid model, it is shown that in a collisional sheath there will be upper as well as lower limits for the sheath velocity criterion. However, the parameters of the negative ions only affect the lower limit.

Sport injuries of the cervical spine

International Nuclear Information System (INIS)

Bargon, G.

1981-01-01

The article reports on injuries of the cervical spine occurring during sports activities. An attempt is made to reconstruct the movements which led to the cervical spine injuries in question. In two cases of accidents occuring during bathing, one football accident and a toboggan accident, the injuries concerned point to hyperextension of the cervical spine as cause of the injury. In another football accident and a riding accident, the changes observed allow us to conclude that the movement leading to the injury must have been a hyperflexion. One accident occurring while jumping on the trampolin resulted in an injury of the upper cervical spine pointing to the action of a compressive force on the cervical spine in addition to the force resulting in hyperflexion. (orig.) [de

Sport injuries of the cervical spine

Energy Technology Data Exchange (ETDEWEB)

Bargon, G

1981-03-01

The article reports on injuries of the cervical spine occurring during sports activities. An attempt is made to reconstruct the movements which led to the cervical spine injuries in question. In two cases of accidents occuring during bathing, one football accident and a toboggan accident, the injuries concerned point to hyperextension of the cervical spine as cause of the injury. In another football accident and a riding accident, the changes observed allow us to conclude that the movement leading to the injury must have been a hyperflexion. One accident occurring while jumping on the trampolin resulted in an injury of the upper cervical spine pointing to the action of a compressive force on the cervical spine in addition to the force resulting in hyperflexion.

A Rare Nasal Bone Fracture: Anterior Nasal Spine Fracture

Directory of Open Access Journals (Sweden)

Egemen Kucuk

2014-04-01

Full Text Available Anterior nasal spine fractures are a quite rare type of nasal bone fractures. Associated cervical spine injuries are more dangerous than the nasal bone fracture. A case of the anterior nasal spine fracture, in a 18-year-old male was presented. Fracture of the anterior nasal spine, should be considered in the differential diagnosis of the midface injuries and also accompanying cervical spine injury should not be ignored.

Primary epidural liposarcoma of the cervical spine: Technical case report and review of the literature

Directory of Open Access Journals (Sweden)

Hamid Borghei-Razavi

2015-03-01

Full Text Available Liposarcoma is the most common soft tissue sarcoma in adults. These tumors have a high incidence of osseous metastases, with a propensity to the spine; however, primary spinal involvement is very rare. A 56-year-old female patient presented with a 4 month history of cervical pain, including radiation to both upper limbs, without radicular distribution. Magnetic resonance imaging (MRI showed an epidural lesion with gadolinium enhancement and bilateral extension into the intervertebral neural foramina (C5–C7, with spreading on the right side of the tumor into paravertebral tissue. The histopathological diagnosis was myxoid liposarcoma. To our knowledge it is the first case of primary myxoid liposarcoma of the cervical spine in the literature. Although rare, our case demonstrates that liposarcoma should be considered in the differential diagnosis of cervical tumors.

Malignant peripheral nerve sheath tumor associated with neurofibromatosis type 1, with metastasis to the heart: a case report

Directory of Open Access Journals (Sweden)

Araki Nobuhito

2010-01-01

Full Text Available Abstract A rare case is presented of a 61-year-old man with a malignant peripheral nerve sheath tumor associated with neurofibromatosis type 1, with metastasis to the heart. The primary tumor originated in the right thigh in 1982. Since then, the patient has had repeated local recurrences in spite of repeated surgical treatment and adjuvant chemotherapy. He has developed previous metastases of the lung and heart. The patient died of cardiac involvement.

Total spine and posterior fossa MRI screening in adolescent idiopathic scoliosis (177 cases

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MR Etemadifar

2005-05-01

Full Text Available Background: MRI screening for idiopathic scoliosis is controversial. Considering our clinical experiences, the results of MRI in all patients with idiopathic scoliosis were evaluated. Methods: In a prospective clinical study, all neurologically normal patients with idiopathic scoliosis screened by posterior fossa and total spine MRI. Results: After excluding 9 patients for mild neurological findings, in other 177 patients (132 female, 45 male, the average age and curve angle was 15±2 years and 59±17º (30 to 135º, respectively. Convexity was to right in 146 and to left in 31 cases. MRI was positive in 12 cases (6.8%. In 5 cases (2.8%, neurosurgical intervention was necessary prior to scoliosis surgery. There was no relation between age, sex, presence of pain or curve angle and positive MRI findings (P>0.05. Left convexity was significantly related to positive MRI findings (P=0.013. In males with left convex curves, the probability of positive MRI findings was 8.8 folds other patients. Conclusion: Considering our results and other reported articles, it seems that routine MRI screening of all patients presenting as idiopathic scoliosis is necessary for detection of underlying pathologies. Key words: Idiopathic Scoliosis, MRI, Spine Syrinx, Chiari

Aquatic antagonists: cutaneous sea urchin spine injury.

Science.gov (United States)

Hsieh, Clifford; Aronson, Erica R; Ruiz de Luzuriaga, Arlene M

2016-11-01

Injuries from sea urchin spines are commonly seen in coastal regions with high levels of participation in water activities. Although these injuries may seem minor, the consequences vary based on the location of the injury. Sea urchin spine injuries may cause arthritis and synovitis from spines in the joints. Nonjoint injuries have been reported, and dermatologic aspects of sea urchin spine injuries rarely have been discussed. We present a case of a patient with sea urchin spines embedded in the thigh who subsequently developed painful skin nodules. Tissue from the site of the injury demonstrated foreign-body type granulomas. Following the removal of the spines and granulomatous tissue, the patient experienced resolution of the nodules and associated pain. Extraction of sea urchin spines can attenuate the pain and decrease the likelihood of granuloma formation, infection, and long-term sequelae.

Intracerebellar malignant nerve sheath tumor in a child: case report and review of literature.

Science.gov (United States)

Joshi, Krishna Chaitanya; Chakravarthy, Hariprakash; Subramanian, Nirmala

2015-05-01

Intracerebellar malignant nerve sheath tumor (ICMNST) is an extremely rare entity, only two cases have been reported previously, and this is the first case to be reported in a child. The histogenesis, diagnosis, and management of this entity are very ambiguous, and natural history in a child is unknown. The authors report a 7-year-old girl who presented with ataxia and signs of raised intracranial pressure and discuss the challenges in diagnosis, surgical strategy, and treatment. Following gross total resection and radiation to tumor bed, the patient had unremarkable recovery and is recurrence free at 1-year follow-up. ICMNSTs are extremely rare tumors of the cerebellum. Preoperative radiological diagnosis is not possible due to its close radiological resemblance to other common posterior fossa tumors. Immunohistochemistry plays a pivotal role in clinching the diagnosis. Though the reported adult counterparts have shown dismal prognosis, the pediatric counterparts may fare better with good surgical resection followed by radiotherapy.

Mitigating impact of thermal and rectified radio-frequency sheath potentials on edge localized modes

Energy Technology Data Exchange (ETDEWEB)

Gui, B. [Institute of Plasma Physics Chinese Academy of Sciences, Hefei (China); Lawerence Livermore National Lab, Livermore, California 94550 (United States); Xu, X. Q. [Lawerence Livermore National Lab, Livermore, California 94550 (United States); Myra, J. R.; D' Ippolito, D. A. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States)

2014-11-15

The mitigating impact of thermal and rectified radio frequency (RF) sheath potentials on the peeling-ballooning modes is studied non-linearly by employing a two-fluid three-field simulation model based on the BOUT++ framework. Additional shear flow and the Kelvin-Helmholtz effect due to the thermal and rectified RF sheath potential are induced. It is found that the shear flow increases the growth rate while the K-H effect decreases the growth rate slightly when there is a density gradient, but the energy loss of these cases is suppressed in the nonlinear phase. The stronger external electrostatic field due to the sheaths has a more significant effect on the energy loss suppression. From this study, it is found the growth rate in the linear phase mainly determines the onset of edge-localized modes, while the mode spectrum width in the nonlinear phase has an important impact on the turbulent transport. The wider mode spectrum leads to weaker turbulent transport and results in a smaller energy loss. Due to the thermal sheath and rectified RF sheath potential in the scrape-off-layer, the modified shear flow tears apart the peeling-ballooning filament and makes the mode spectrum wider, resulting in less energy loss. The perturbed electric potential and the parallel current near the sheath region is also suppressed locally due to the sheath boundary condition.

Stability of the plasma sheath

International Nuclear Information System (INIS)

Franklin, R.N.

1979-12-01

The stability of a collisionless sheath joined to a plasma in the presence of secondary emission of electrons from the sheath boundary is examined in the fluid approximation. Instability is unlikely to occur under floating conditions but if significant currents flow corresponding to increased wall-plasma potentials the system can go unstable. (author)

Injuries of the upper cervical spine: A series of 28 cases

Directory of Open Access Journals (Sweden)

Basu Saumyajit

2007-01-01

Full Text Available Background: There are very few published reports of upper cervical spine injuries from our country and there is a heavy bias towards operative treatment of these injuries. We present below our experience of upper cervical injuries over the last four years. Materials and Methods: Twenty eight patients (20 males, 8 females with upper cervical spine injury (including Occiput, Atlas and Axis were treated and were followed-up for an average of 11.2 months. The data was analyzed retrospectively with regards to the location and type of injury, the treatment offered (conservative or operative as well as the final clinical and radiological outcome. Results: The clinico-radiological outcome of treatment of these injuries is mostly very good with few complications. Other than a single case of mortality due to associated head injury there were no major complications. Conclusion: Management of these patients needs a proper evaluation to arrive at the type of injury and prompt conservative or operative treatment. Treatment is usually safe and effective with good clinical and radiological outcome.

A case of a traumatic chyle leak following an acute thoracic spine injury: successful resolution with strict dietary manipulation

Directory of Open Access Journals (Sweden)

Skinner Ruby A

2011-03-01

Full Text Available Abstract Background Chylothorax is a rare form of pleural effusion that can be associated with both traumatic and non-traumatic causes. Thoracic duct ligation is often the treatment of choice in postsurgical patients; however the optimal treatment of this disease process after traumatic injury remains unclear 1. We present a rare case of a thoracic duct injury secondary to a blunt thoracic spine fracture and subluxation which was successfully treated non-operatively. Case Presentation A 51 year old male presented as a tier one trauma code due to an automobile versus bicycle collision. His examination and radiographic work-up revealed fractures and a subluxation at the third and fourth thoracic spine levels resulting in paraplegia. He also sustained bilateral hemothoraces secondary to multiple rib fractures. Drainage of the left hemothorax led to the diagnosis of a traumatic chylothorax. The thoracic spine fractures were addressed with surgical stabilization and the chylothorax was successfully treated with drainage and dietary manipulation. Conclusions This unusual and complex blunt thoracic duct injury required a multidisciplinary approach. Although the spine injury required surgical fixation, successful resolution of the chyle leak was achieved without surgical intervention.

Paediatric cervical spine injury but NEXUS negative

OpenAIRE

Maxwell, Melanie J; Jardine, Andrew D

2007-01-01

Cervical spine injuries in paediatric patients following trauma are extremely rare. The National Emergency X‐Radiography Utilization Study (NEXUS) guidelines are a set of clinical criteria used to guide physicians in identifying trauma patients requiring cervical spine imaging. It is validated for use in children. A case of a child who did not fulfil the NEXUS criteria for imaging but was found to have a cervical spine fracture is reported.

Rectus sheath abscess after laparoscopic appendicectomy

Directory of Open Access Journals (Sweden)

Golash Vishwanath

2007-01-01

Full Text Available Port site wound infection, abdominal wall hematoma and intraabdominal abscess formation has been reported after laparoscopic appendicectomy. We describe here a rectus sheath abscess which occurred three weeks after the laparoscopic appendicectomy. It was most likely the result of secondary infection of the rectus sheath hematoma due to bleeding into the rectus sheath from damage to the inferior epigastric arteries or a direct tear of the rectus muscle. As far as we are aware this complication has not been reported after laparoscopic appendicectomy.

Collision-dominated dust sheaths and voids - observations in micro-gravity experiments and numerical investigation of the force balance relations

International Nuclear Information System (INIS)

Tsytovich, V N; Morfill, G; Konopka, U; Thomas, H

2003-01-01

Numerical solutions of stationary force balance equations are used to investigate the possible dust configurations (dust structures) in complex plasmas between two floating potential plane electrodes. The distance between electrodes is assumed to be larger than the ion-neutral mean free path and the hydrodynamic description is used. It includes the known forces operating in this limit, the ionization source and the dust charge variations. The stationary balance equations are solved both in the case of the presence of one-size dust grains and for the case of a mixture of grains with two different sizes. Recent micro-gravity experiments with single-size dust grains and two-different-size dust grains show the formation of a system of dust sheaths and dust voids between the two plane electrodes. The observed configurations of dust structures depend strongly on the gas pressure and the degree of ionization used. The numerical investigations are able to show the necessary conditions for the types of structure to be created and give their size. The size of the structures observed is larger than the ion-neutral mean free path and is of the order of magnitude of that obtained numerically. The numerical investigations give details of the spatial distributions, the dust particles, the electron/ion densities, the ion drift velocity and dust charges inside and outside different dust structures. These details have not yet been investigated experimentally and can indicate directions for further experimental work to be performed. The single-dust-sheath structure with single-size dust particles surrounded by dust free regions (dust wall-voids) and floating potential electrodes is computed. Such a structure was observed recently and the computational results are in agreement with observations. It is shown that more often a dust void in the centre is observed. It is found that a dust void in the centre region between two electrodes is formed if the ionization rate is larger than the

The characteristics of RF modulated plasma boundary sheaths: An analysis of the standard sheath model

Science.gov (United States)

Naggary, Schabnam; Brinkmann, Ralf Peter

2015-09-01

The characteristics of radio frequency (RF) modulated plasma boundary sheaths are studied on the basis of the so-called ``standard sheath model.'' This model assumes that the applied radio frequency ωRF is larger than the plasma frequency of the ions but smaller than that of the electrons. It comprises a phase-averaged ion model - consisting of an equation of continuity (with ionization neglected) and an equation of motion (with collisional ion-neutral interaction taken into account) - a phase-resolved electron model - consisting of an equation of continuity and the assumption of Boltzmann equilibrium -, and Poisson's equation for the electrical field. Previous investigations have studied the standard sheath model under additional approximations, most notably the assumption of a step-like electron front. This contribution presents an investigation and parameter study of the standard sheath model which avoids any further assumptions. The resulting density profiles and overall charge-voltage characteristics are compared with those of the step-model based theories. The authors gratefully acknowledge Efe Kemaneci for helpful comments and fruitful discussions.

Evaluation and management of 2 ferocactus spines in the orbit.

Science.gov (United States)

Russell, David J; Kim, Tim I; Kubis, Kenneth

2013-01-01

A 49-year-old woman, who had fallen face first in a cactus 1 week earlier, presented with a small, mobile, noninflamed subcutaneous nodule at the rim of her right lateral orbit with no other functional deficits. A CT scan was obtained, which revealed a 4-cm intraorbital tubular-shaped foreign body resembling a large cactus spine. A second preoperative CT scan, obtained for an intraoperative guidance system, demonstrated a second cactus spine, which was initially not seen on the first CT scan. Both spines were removed surgically without complication. The authors discuss factors that can cause diagnosis delay, review the radiographic features of cactus spines, and discuss the often times benign clinical course of retained cactus spine foreign bodies. To the authors' knowledge, this is the first case report of cactus spines in the orbit. Health-care professionals should have a low threshold for imaging in cases of traumatic injuries involving cactus spines.

Sheath heating in low-pressure capacitive radio frequency discharges

International Nuclear Information System (INIS)

Wood, B.P.

1991-01-01

Capacitively coupled, parallel plate, r.f. discharges are commonly used for materials processing. The electrons in such a discharge gain and lose energy by reflection from the oscillating sheaths which form at the electrodes. Previous models of the electron heating by this mechanism have assumed that the sheath motion is slow compared to the electron thermal velocity, so that the electron energy change from each reflection is small. Here, the heating rate, density, and sheath width relations are derived analytically in the limit of very fast sheath motion. Numerical results are presented spanning the slow and fast limits. Results from particle-in-cell simulations show that in the large-energy-change regime, an electron beam is produced on each sheath expansion. At low pressure, this beam can traverse the plasma and interact with the sheath at the opposite electrode, producing a beam energy and density dependence on the length of the discharge. The beam produces a time and space varying warm tail on the electron energy distribution. Two revised heating models are derived, assuming power-law and two-temperature electron energy distributions, with temporal variation in electron temperature. These revised models yield new predictions for the variation of the power, density, and sheath thickness with applied r.f. voltage. These predictions are compared with simulation results and laboratory experiment. The electron sheath motion is investigated experimentally by observing the signal on a floating probe in the sheath region. This is compared to the signal product by a non-linear circuit model which accounts for the perturbation of the sheath potential by the probe and includes various forms of sheath motion. The experimental observations are consistent with the analytical predictions. Experimental observations of plasma-sheath resonance oscillations are presented which agree with analytical predictions

Research on stress distribution regularity of cement sheaths of radial well based on ABAQUS

Science.gov (United States)

Shi, Jihui; Cheng, Yuanfang; Li, Xiaolong; Xiao, Wen; Li, Menglai

2017-12-01

To ensure desirable outcome of hydraulic fracturing based on ultra-short radius radial systems, it is required to investigate the stress distribution regularity and stability of the cement sheath. On the basis of the theoretical model of the cement sheath stress distribution, a reservoir mechanical model was built using the finite element software, ABAQUS, according to the physical property of a certain oil reservoir of the Shengli oilfield. The stress distribution of the casing-cement-sheath-formation system under the practical condition was simulated, based on which analyses were conducted from multiple points of view. Results show that the stress on the internal interface of the cement sheath exceeds that on the external interface, and fluctuates with higher amplitudes, which means that the internal interface is the most failure-prone. The unevenness of the cement sheath stress distribution grows with the increasing horizontal principal stress ratio, and so does the variation magnitude. This indicates that higher horizontal principal stress ratios are unfavourable for the structural stability of the cement sheath. Both the wellbore quantity of the URRS and the physical property of the material can affect the cement sheath distribution. It is suggested to optimize the quantity of the radial wellbore and use cement with a lower elastic modulus and higher Poisson’s ratio. At last, the impact level of the above factor was analysed, with the help of the grey correlation analysis.

Global Reconstruction for Extensive Destruction in Tuberculosis of the Lumbar Spine and Lumbosacral Junction: A Case Report

Science.gov (United States)

Uvaraj, Nalli R.; Bosco, Aju; Gopinath, Nalli R.

2014-01-01

Study Design Case report. Objective To analyze the surgical difficulties in restoring global spinal stability and to describe an effective surgical option for tuberculosis with extensive destruction of the lumbosacral spine. Advanced tuberculosis with destruction of the lumbosacral spine can result in a kyphosis or hypolordosis, leading to back pain, spinal instability, and neurological deficits. The conventional treatment goals of lumbosacral tuberculosis are to correct and prevent a lumbar kyphosis, treat or prevent a neurological deficit, and restore global spinal stability. Instrumentation at the lumbosacral junction is technically demanding due to the complex local anatomy, the unique biomechanics, and the difficult fixation in the surrounding diseased bone. Methods We report a 21-year-old woman with tuberculosis from L1 to S2 with back pain and spinal instability. The radiographs showed a kyphosis of the lumbar spine. The magnetic resonance imaging and computed tomography scans revealed extensive destruction of the lumbar and lumbosacral spine. Spinopelvic stabilization combined with anterior debridement and reconstruction with free fibular strut graft was performed. Results The radiographs at follow-up showed a good correction of the kyphosis and excellent graft incorporation and fusion. Conclusions Anterior column reconstruction with a fibular strut graft helps restore and maintain the vertebral height. Posterior stabilization with spinopelvic fixation can be an effective surgical option for reconstructing the spine in extensive lumbosacral tuberculosis with sacral body destruction, requiring long fusions to the sacrum. It augments spinal stability, prevents graft-related complications, and accelerates the graft incorporation and fusion, thereby permitting early mobilization and rehabilitation. In spinal tuberculosis, antitubercular therapy may have to be prolonged in cases with large disease load, based on the clinicoradiographic and laboratory

Bilateral locked facets in the thoracic spine

NARCIS (Netherlands)

M.H.A. Willems; Braakman, R. (Reinder); B. van Linge (Bert)

1984-01-01

textabstractTwo cases of traumatic bilateral locked facets in the thoracic spine are reported. Both patients had only minor neurological signs. They both made a full neurological recovery after surgical reduction of the locked facets. Bilateral locked facets are very uncommon in the thoracic spine.

Are black holes in alternative theories serious astrophysical candidates? The case for Einstein-dilaton-Gauss-Bonnet black holes

International Nuclear Information System (INIS)

Pani, Paolo; Cardoso, Vitor

2009-01-01

It is generally accepted that Einstein's theory will get some as yet unknown corrections, possibly large in the strong-field regime. An ideal place to look for these modifications is in the vicinities of compact objects such as black holes. Here, we study dilatonic black holes, which arise in the framework of Gauss-Bonnet couplings and one-loop corrected four-dimensional effective theory of heterotic superstrings at low energies. These are interesting objects as a prototype for alternative, yet well-behaved gravity theories: they evade the 'no-hair' theorem of general relativity but were proven to be stable against radial perturbations. We investigate the viability of these black holes as astrophysical objects and try to provide some means to distinguish them from black holes in general relativity. We start by extending previous works and establishing the stability of these black holes against axial perturbations. We then look for solutions of the field equations describing slowly rotating black holes and study geodesic motion around this geometry. Depending on the values of mass, dilaton charge, and angular momentum of the solution, one can have differences in the innermost-stable-circular-orbit location and orbital frequency, relative to black holes in general relativity. In the most favorable cases, the difference amounts to a few percent. Given the current state-of-the-art, we discuss the difficulty of distinguishing the correct theory of gravity from electromagnetic observations or even with gravitational-wave detectors.

Measurements of the sheath potential in low density plasmas

International Nuclear Information System (INIS)

Bradley, J.W.; Khamis, R.A.; Sanduk, M.I.; Elliott, J.A.; Rusbridge, M.G.

1992-01-01

We have measured the sheath potential around a probe in a range of different plasma conditions in the UMIST, University of Manchester Institute of Science and Technology, quadrupole GOLUX and in a related experiment in which the plasma expands freely to supersonic velocity. In the latter case, the sheath potential agrees well with an appropriately modified form of the usual expression for a field-free plasma, for both hydrogen and argon plasmas. In GOLUX, however, the sheath potential is found to be significantly less than the accepted value, even when the magnetic field is taken into account. For the slow moving plasma in the outer part of the quadrupole confining field, we present both theoretical and experimental results showing that the reduction is due to truncation of the electron velocity distribution as the probe drains electrons from a closed flux tube faster than they can be replaced. In the central hot plasma, however, this explanation cannot apply. Here, the plasma is moving at about sonic speed and magnetic effects are weak. Nevertheless, the results are significantly different from both in the field free experiment. (author)

Recurrent spine surgery patients in hospital administrative database

Directory of Open Access Journals (Sweden)

M. Sami Walid

2012-02-01

Full Text Available Introduction: Hospital patient databases are typically used by administrative staff to estimate loss-profit ratios and to help with the allocation of hospital resources. These databases can also be very useful in following rehospitalization. This paper studies the recurrence of spine surgery patients in our hospital population based on administrative data analysis. Methods: Hospital data on 4,958 spine surgery patients operated between 2002 and 2009 were retrospectively reviewed. After sorting the cohort per ascending discharge date, the patient official name, consisting of first, middle and last names, was used as the variable determining duplicate cases in the SPSS statistical program, designating the first case in each group as primary. Yearly recurrence rate and change in procedure distribution were studied. In addition, hospital charges and length of stay were compared using the Wilcoxon-Mann-Whitney test. Results: Of 4,958 spine surgery patients 364 (7.3% were categorized as duplicate cases by SPSS. The number of primary cases from which duplicate cases emerged was 327 meaning that some patients had more than two spine surgeries. Among primary patients (N=327 the percentage of excision of intervertebral disk procedures was 33.3% and decreased to 15.1% in recurrent admissions of the same patients (N=364. This decrease was compensated by an increase in lumbar fusion procedures. On the other hand, the rate of cervical fusion remained the same. The difference in hospital charges between primary and duplicate patients was $2,234 for diskectomy, $6,319 for anterior cervical fusion, $8,942 for lumbar fusion – lateral technique, and $12,525 for lumbar fusion – posterior technique. Recurrent patients also stayed longer in hospital, up to 0.9 day in lumbar fusion – posterior technique patients. Conclusion: Spine surgery is associated with an increasing possibility of additional spine surgery with rising invasiveness and cost.

Sheath structure transition controlled by secondary electron emission

Science.gov (United States)

Schweigert, I. V.; Langendorf, S. J.; Walker, M. L. R.; Keidar, M.

2015-04-01

In particle-in-cell Monte Carlo collision (PIC MCC) simulations and in an experiment we study sheath formation over an emissive floating Al2O3 plate in a direct current discharge plasma at argon gas pressure 10-4 Torr. The discharge glow is maintained by the beam electrons emitted from a negatively biased hot cathode. We observe three types of sheaths near the floating emissive plate and the transition between them is driven by changing the negative bias. The Debye sheath appears at lower voltages, when secondary electron emission is negligible. With increasing applied voltage, secondary electron emission switches on and a first transition to a new sheath type, beam electron emission (BEE), takes place. For the first time we find this specific regime of sheath operation near the floating emissive surface. In this regime, the potential drop over the plate sheath is about four times larger than the temperature of plasma electrons. The virtual cathode appears near the emissive plate and its modification helps to maintain the BEE regime within some voltage range. Further increase of the applied voltage U initiates the second smooth transition to the plasma electron emission sheath regime and the ratio Δφs/Te tends to unity with increasing U. The oscillatory behavior of the emissive sheath is analyzed in PIC MCC simulations. A plasmoid of slow electrons is formed near the plate and transported to the bulk plasma periodically with a frequency of about 25 kHz.

Application of Spray Foam Insulation Under Plywood and Oriented Strand Board Roof Sheathing

Energy Technology Data Exchange (ETDEWEB)

Grin, A. [Building Science Corporation, Somerville, MA (United States); Smegal, J. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

2013-10-01

Unvented roof strategies with open cell and closed cell spray polyurethane foam insulation sprayed to the underside of roof sheathing have been used since the mid-1990's to provide durable and efficient building enclosures. However, there have been isolated moisture related incidents reported anecdotally that raise potential concerns about the overall hygrothermal performance of these systems. This project involved hygrothermal modeling of a range of rainwater leakage and field evaluations of in-service residential roofs using spray foam insulation. All of the roof assemblies modeled exhibited drying capacity to handle minor rainwater leakage. All field evaluation locations of in-service residential roofs had moisture contents well within the safe range for wood-based sheathing. Explorations of eleven in-service roof systems were completed. The exploration involved taking a sample of spray foam from the underside of the roof sheathing, exposing the sheathing, then taking a moisture content reading. All locations had moisture contents well within the safe range for wood-based sheathing. One full-roof failure was reviewed, as an industry partner was involved with replacing structurally failed roof sheathing. In this case the manufacturer's investigation report concluded that the spray foam was installed on wet OSB based on the observation that the spray foam did not adhere well to the substrate and the pore structure of the closed cell spray foam at the ccSPF/OSB interface was indicative of a wet substrate.

Retroperitoneal Malignant Peripheral Nerve Sheath Tumor Replacing an Absent Kidney in a Child

Directory of Open Access Journals (Sweden)

Samin Alavi

2013-01-01

Full Text Available Malignant peripheral nerve sheath tumors (MPNSTs are nonrhabdomyosarcoma soft tissue sarcomas with rare occurrence in children specially in the retroperitoneum. We describe a young child who presented with an abdominal mass. Both ultrasound and computed tomography revealed a large right-sided abdominal mass in the anatomic place of right kidney, while no kidney or ureter was observed at that side. He underwent surgical resection of the tumor with a primary impression of Wilms tumor. To the authors’ knowledge, this is the first case of retroperitoneal malignant peripheral nerve sheath tumor and absent kidney. This case suggests the very rare probability of association of MPNSTs in children with genitourinary tract anomalies such as renal agenesis.

Post-mortem MRI of the foetal spine and spinal cord

International Nuclear Information System (INIS)

Widjaja, E.; Whitby, E.H.; Cohen, M.; Paley, M.N.J.; Griffiths, P.D.

2006-01-01

Aims: To compare the findings of post-mortem magnetic resonance imaging (MRI) of the foetal spine with autopsy with a view to using post-mortem MRI as an alternative or adjunct to autopsy, particularly in foetal and neonatal cases. Materials and Methods: The brains and spines of 41 foetuses, with a gestational age range of 14-41 weeks, underwent post-mortem MRI before autopsy. Post-mortem MRI of the brain consisted of T2-weighted sequences in three orthogonal planes and MRI of the spine consisted of T2-weighted sequence in the sagittal and axial planes in all cases and coronal planes in selected cases. Results: Thirty of 41 (78%) foetal spines were found to be normal at autopsy and on post-mortem MRI. Eleven of 41 (22%) foetal spines were abnormal: eight foetuses had myelomeningocoeles and Chiari 2 deformities, one foetus had limited dorsal myeloschisis, one foetus had caudal regression syndrome, and one had diastematomyelia. The post-mortem MRI findings concurred with the autopsy findings in 10/11 of the abnormal cases, the disagreement being the case of diastematomyelia that was shown on post-mortem MRI but was not diagnosed at autopsy. Conclusions: In this series, post-mortem MRI findings agreed with the autopsy findings in 40/41(98%) cases and in one case the post-mortem MRI demonstrated an abnormality not demonstrated at autopsy

The medicolegal landscape of spine surgery: how do surgeons fare?

Science.gov (United States)

Makhni, Melvin C; Park, Paul J; Jimenez, Jesus; Saifi, Comron; Caldwell, Jon-Michael; Ha, Alex; Figueroa-Santana, Bianca; Lehman, Ronald A; Weidenbaum, Mark

2018-02-01

Because of the limited and confidential nature of most legal data, scarce literature is available to physicians about reasons for litigation in spine surgery. To optimally compensate patients while protecting physicians, further understanding of the medicolegal landscape is needed for high-risk procedures such as spine surgery. Based on these, surgeons can explore ways to better protect both their patients and themselves. To characterize the current medicolegal environment of spine surgery by analyzing a recent dataset of malpractice litigation. A retrospective study. All malpractice cases involving spine surgery available to public query between the years of 2010 and 2014. Case outcome for spine surgery malpractice cases between the years of 2010 and 2014. WestlawNext was used to analyze spine surgery malpractice cases at the state and federal level between the years 2010 and 2014. WestlawNext is a subscription-based, legal search engine that contains publicly available federal and state court records. All monetary values were inflation adjusted for 2016. One hundred three malpractice cases were categorized by case descriptors and outcome measures. Claims were categorized as either intraoperative complaints or preoperative complaints. Rulings in favor of the defendant (surgeon) were noted in 75% (77 of 103) of the cases. Lack of informed consent was cited in 34% of cases. For the 26 cases won by the plaintiff, the average amount in settlement was $2,384,775 versus $3,945,456 in cases brought before a jury. Cases involving consent averaged a compensation of $2,029,884, whereas cases involving only intraoperative complaints averaged a compensation of $3,667,530. A significant correlation was seen between increased compensation for plaintiffs and cases involving orthopedic surgeons (p=.020) or nerve injury (p=.005). Wrong-level surgery may be associated with lower plaintiff compensation (p=.055). The length of cases resulting in defense verdicts averaged 5.51 years

The effect of holes in long-lasting insecticidal nets on malaria in Malawi: results from a case-control study.

Science.gov (United States)

Minta, Anna A; Landman, Keren Z; Mwandama, Dyson A; Shah, Monica P; Eng, Jodi L Vanden; Sutcliffe, James F; Chisaka, Joseph; Lindblade, Kim A; Mathanga, Don P; Steinhardt, Laura C

2017-10-02

Long-lasting insecticidal nets (LLINs) are a cornerstone of malaria prevention. Holes develop in LLINs over time and compromise their physical integrity, but how holes affect malaria transmission risk is not well known. After a nationwide mass LLIN distribution in July 2012, a study was conducted to assess the relationship between LLIN damage and malaria. From March to September 2013, febrile children ages 6-59 months who consistently slept under LLINs (every night for 2 weeks before illness onset) were enrolled in a case-control study at Machinga District Hospital outpatient department. Cases were positive for Plasmodium falciparum asexual parasites by microscopy while controls were negative. Digital photographs of participants' LLINs were analysed using an image-processing programme to measure holes. Total hole area was classified by quartiles and according to the World Health Organization's proportionate hole index (pHI) cut-offs [ 790 cm 2 (too torn)]. Number of holes by location and size, and total hole area, were compared between case and control LLINs using non-parametric analyses and logistic regression. Of 248 LLINs analysed, 97 (39%) were from cases. Overall, 86% of LLINs had at least one hole. The median number of holes of any size was 9 [interquartile range (IQR) 3, 22], and most holes were located in the lower halves of the nets [median 7 (IQR 2, 16)]. There were no differences in number or location of holes between LLINs used by cases and controls. The median total hole area was 10 cm 2 (IQR 2, 125) for control LLINs and 8 cm 2 (IQR 2, 47) for case LLINs (p = 0.10). Based on pHI, 109 (72%) control LLINs and 83 (86%) case LLINs were in "good" condition. Multivariable modeling showed no association between total hole area and malaria, controlling for child age, caregiver education, and iron versus thatched roof houses. LLIN holes were not associated with increased odds of malaria in this study. However, most of the LLINs were in relatively good

Composition of the sheath produced by the green alga Chlorella sorokiniana.

Science.gov (United States)

Watanabe, K; Imase, M; Sasaki, K; Ohmura, N; Saiki, H; Tanaka, H

2006-05-01

To investigate the chemical characterization of the mucilage sheath produced by Chlorella sorokiniana. Algal mucilage sheath was hydrolysed with NaOH, containing EDTA. The purity of the hydrolysed sheath was determined by an ATP assay. The composition of polysaccharide in the sheath was investigated by high-performance anion-exchange chromatography with pulsed amperometric detection. Sucrose, galacturonic acid, xylitol, inositol, ribose, mannose, arabinose, galactose, rhamnose and fructose were detected in the sheath as sugar components. Magnesium was detected in the sheath as a divalent cation using inductively coupled argon plasma. The sheath matrix also contained protein. It appears that the sheath is composed of sugars and metals. Mucilage sheath contains many kinds of saccharides that are produced as photosynthetic metabolites and divalent cations that are contained in the culture medium. This is the first report on chemical characterization of the sheath matrix produced by C. sorokiniana.

Fibrin Sheath Angioplasty: A Technique to Prevent Superior Vena Cava Stenosis Secondary to Dialysis Catheters

Science.gov (United States)

Hacker, Robert I.; Garcia, Lorena De Marco; Chawla, Ankur; Panetta, Thomas F.

2012-01-01

Fibrin sheaths are a heterogeneous matrix of cells and debris that form around catheters and are a known cause of central venous stenosis and catheter failure. A total of 50 cases of central venous catheter fibrin sheath angioplasty (FSA) after catheter removal or exchange are presented. A retrospective review of an outpatient office database identified 70 eligible patients over a 19-month period. After informed consent was obtained, the dialysis catheter exiting the skin was clamped, amputated, and a wire was inserted. The catheter was then removed and a 9-French sheath was inserted into the superior vena cava, a venogram was performed. If a fibrin sheath was present, angioplasty was performed using an 8 × 4 or 10 × 4 balloon along the entire length of the fibrin sheath. A completion venogram was performed to document obliteration of the sheath. During the study, 50 patients were diagnosed with a fibrin sheath, and 43 had no pre-existing central venous stenosis. After FSA, 39 of the 43 patient's (91%) central systems remained patent without the need for subsequent interventions; 3 patients (7%) developed subclavian stenoses requiring repeat angioplasty and stenting; 1 patent (2.3%) developed an occlusion requiring a reintervention. Seven patients with prior central stenosis required multiple angioplasties; five required stenting of their central lesions. Every patient had follow-up fistulograms to document long-term patency. We propose that FSA is a prudent and safe procedure that may help reduce the risk of central venous stenosis from fibrin sheaths due to central venous catheters. PMID:23997555

Concomitant lower thoracic spine disc disease in lumbar spine MR imaging studies.

Science.gov (United States)

Arana, Estanislao; Martí-Bonmatí, Luis; Dosdá, Rosa; Mollá, Enrique

2002-11-01

Our objective was to study the coexistence of lower thoracic-spine disc changes in patients with low back pain using a large field of view (FOV) in lumbar spine MR imaging. One hundred fifty patients with low back pain were referred to an MR examination. All patients were studied with a large FOV (27 cm), covering from the coccyx to at least the body of T11. Discs were coded as normal, protrusion, and extrusion (either epiphyseal or intervertebral). The relationship between disc disease and level was established with the Pearson chi(2) test. The T11-12 was the most commonly affected level of the lower thoracic spine with 58 disc cases rated as abnormal. Abnormalities of T11-12 and T12-L1 discs were significantly related only to L1-L2 disease ( p=0.001 and p=0.004, respectively) but unrelated to other disc disease, patient's gender, and age. No correlation was found between other discs. Magnetic resonance imaging of the lumbar spine can detect a great amount of lower thoracic disease, although its clinical significance remains unknown. A statistically significant relation was found within the thoracolumbar junctional region (T11-L2), reflecting common pathoanatomical changes. The absence of relation with lower lumbar spine discs is probably due to differences in their pathomechanisms.

Concomitant lower thoracic spine disc disease in lumbar spine MR imaging studies

International Nuclear Information System (INIS)

Arana, Estanislao; Marti-Bonmati, Luis; Dosda, Rosa; Molla, Enrique

2002-01-01

Our objective was to study the coexistence of lower thoracic-spine disc changes in patients with low back pain using a large field of view (FOV) in lumbar spine MR imaging. One hundred fifty patients with low back pain were referred to an MR examination. All patients were studied with a large FOV (27 cm), covering from the coccyx to at least the body of T11. Discs were coded as normal, protrusion, and extrusion (either epiphyseal or intervertebral). The relationship between disc disease and level was established with the Pearson χ 2 test. The T11-12 was the most commonly affected level of the lower thoracic spine with 58 disc cases rated as abnormal. Abnormalities of T11-12 and T12-L1 discs were significantly related only to L1-L2 disease (p=0.001 and p=0.004, respectively) but unrelated to other disc disease, patient's gender, and age. No correlation was found between other discs. Magnetic resonance imaging of the lumbar spine can detect a great amount of lower thoracic disease, although its clinical significance remains unknown. A statistically significant relation was found within the thoracolumbar junctional region (T11-L2), reflecting common pathoanatomical changes. The absence of relation with lower lumbar spine discs is probably due to differences in their pathomechanisms. (orig.)

Studies of irradiated zircaloy fuel sheathing using XPS

Energy Technology Data Exchange (ETDEWEB)

Chan, P K; Irving, K G [Atomic Energy of Canada Ltd., Chalk River, ON (Canada); Hocking, W H; Duclos, A M; Gerwing, A F [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.

1996-12-31

The preliminary results reported here support the hypothesis that CANLUB graphite coating reduces the rate at which oxygen can react with fuel sheathing. X-ray photoelectron spectroscopic (XPS) characterization of Zircaloy sheathing obtained from extended-burnup Bruce-type elements (BDL-406-XY (555 MW.h/kgU) and BDL-406-AAH (731 MW.h/kgU)) irradiated in NRU indicates that CANLUB may reduce fuel sheath oxidation, and hence that fission-liberated oxygen may remain in the fuel. Chemical shifts in the Zr 3d spectra suggest that a stoichiometric (ZrO{sub 2}) oxide film was formed only on Zircaloy in direct contact with fuel. Particulate fuel adhering to the sheath was also determined to be systematically more oxidized on surfaces with CANLUB than on those without it. The unique association of tin on sheathing specimens with the non-CANLUB-coated specimens might also suggest that the tin had segregated from the sheathing. It must be emphasized that further experiments are required to better define the effect of CANLUB on fuel oxidation. (author). 14 refs., 1 tab., 3 figs.

Studies of irradiated zircaloy fuel sheathing using XPS

International Nuclear Information System (INIS)

Chan, P.K.; Irving, K.G.; Hocking, W.H.; Duclos, A.M.; Gerwing, A.F.

1995-01-01

The preliminary results reported here support the hypothesis that CANLUB graphite coating reduces the rate at which oxygen can react with fuel sheathing. X-ray photoelectron spectroscopic (XPS) characterization of Zircaloy sheathing obtained from extended-burnup Bruce-type elements (BDL-406-XY (555 MW.h/kgU) and BDL-406-AAH (731 MW.h/kgU)) irradiated in NRU indicates that CANLUB may reduce fuel sheath oxidation, and hence that fission-liberated oxygen may remain in the fuel. Chemical shifts in the Zr 3d spectra suggest that a stoichiometric (ZrO 2 ) oxide film was formed only on Zircaloy in direct contact with fuel. Particulate fuel adhering to the sheath was also determined to be systematically more oxidized on surfaces with CANLUB than on those without it. The unique association of tin on sheathing specimens with the non-CANLUB-coated specimens might also suggest that the tin had segregated from the sheathing. It must be emphasized that further experiments are required to better define the effect of CANLUB on fuel oxidation. (author). 14 refs., 1 tab., 3 figs

Dynamic sheath studies in plasma source ion implantation

International Nuclear Information System (INIS)

Schever, J.T.; Shamim, M.; Conrad, J.R.

1990-01-01

Plasma Source Ion Implantation (PSII) is a non-line-of-sight method for materials processing in which a target is immersed in a plasma and pulse biased to a high negative voltage (∼ 50 kV). A model of the dynamic sheath which forms under these conditions has been developed and applied to planar, cylindrical and spherical geometries. This model assumes that the transient sheath obeys the Child-Langmuir law for space charge limited emission at each instant during the propagation. Ions uncovered by the propagating sheath edge supply the space charge limited current. This yields an equation relating sheath edge velocity to position, which can be integrated to obtain the sheath edge position as a function of time. The same procedure used in cylindrical and spherical geometry results in a similar equation which must be integrated numerically. Comparison of results of experimental measurements, our model and simulation will be presented for the dynamic sheath edge position and target current waveform. Measurements of implanted dose uniformity of wedge shaped targets are also presented

Analytical expression for sheath edge around corner cathodes

International Nuclear Information System (INIS)

Sheridan, T E

2009-01-01

A simple analytical expression for the position of the sheath edge around a two-dimensional corner cathode with included angle θ c has been discovered. This expression is valid for weakly collisional sheaths in the Child-Langmuir regime φ c >> kT e /e, where -φ c e is the electron temperature. In polar coordinates (r, θ), the sheath edge is given by (r/s 0 )sin[πθ/(2π - θ c )] = [π/(2π - θ c )] where s 0 is the planar sheath width far from the vertex of the corner. This result is verified by comparison with previous numerical solutions (Watterson P A 1989 J. Phys. D: Appl. Phys. 22 1300) for the knife edge (θ c = 0) and convex square corner (θ c = π/2). The observed agreement suggests that this expression gives the sheath edge for all corner angles, both concave and convex. The utility of this result is demonstrated by computing the full sheath solution for a knife-edge cathode with φ c = 100kT e /e.

Delayed intracranial subdural empyema following burr hole drainage: Case series and literature review.

Science.gov (United States)

Kim, You-Sub; Joo, Sung-Pil; Song, Dong-Jun; Kim, Sung-Hyun; Kim, Tae-Sun

2018-05-01

A subdural empyema (SDE) following burr hole drainage of a chronic subdural hematoma (CSDH) can be difficult to distinguish from a recurrence of the CSDH, especially when imaging data is limited to a computed tomography (CT) scan. All patients underwent burr hole drainage of the CSDH at first, and the appearance of the SDE occurred within one month. A contrast-enhanced magnetic resonance imaging (MRI) scan, with diffusion-weighted imaging (DWI), revealed both the SDE and diffuse meningitis in all patients. In Case 1, because the patient was very young, burr hole drainage of the SDE, rather than craniotomy, was performed. However, subsequent craniotomy was required due to recurrence of the SDE. In Cases 2 and 3, an initial craniotomy was performed without burr hole drainage. Symptoms improved for all patients, and each was discharged without any neurologic deficits or subsequent recurrence. Neurosurgeons should consider the possibility of infection if recurrence of CSDH occurs within 1 month following drainage of a subdural hematoma. A contrast-enhanced MRI with DWI should be performed to differentiate SDE from CSDH. In addition, surgical evacuation of the empyema via wide craniotomy is preferred to burr hole drainage.

Malignant Peripheral Nerve Sheath Tumor: MRI and CT Findings

Directory of Open Access Journals (Sweden)

K. O. Kragha

2015-01-01

important in its diagnosis. A rare case of MPNST that produced urinary retention and bowel incontinence is presented that may aid clinicians in the diagnosis of this rare clinical entity. Motor weakness, central enhancement, and immunohistochemistry may assist in the diagnosis of MPNST and differentiation between benign peripheral nerve sheath tumor (BPNST and MPNST.

Tuberculosis of the spine

Energy Technology Data Exchange (ETDEWEB)

Psarras, H.; Faraj, J.; Gouliamos, A.; Kalovidouris, A.; Vlahos, L.; Papavassiliou, C.

1985-07-01

Two surgically proven cases of turberculous psoas abscess are presented. The common findings on CT were low-density paraspinal masses and extension of the lesions which followed the typical distribution of iliopsoas muscle in both cases. The skeletal findings from the spine are also discussed. Our cases indicate the complementary use of plain radiography and CT in the investigation of tuberculous spondylitis.

Imaging of spine injuries

International Nuclear Information System (INIS)

Lomoschitz, F. . e-mai: friedrich.lomoschitz@univie.ac.at

2001-01-01

Spinal trauma requires a prompt and detailed diagnosis for estimating the prognosis and installing proper therapy. Conventional radiograms are the first imaging modality in most cases. In the cervical and the lumbar spine, a CT has to be performed in patients with polytrauma and a higher risk of complications or with signs of instability. Especially for imaging the cervicocranium, multiplanar reformations in sagittal and coronal planes are necessary. For fractures of the thoracic spine, MR imaging is superior to CT because of the better detection of associated neurologic complications. (author)

Non-Maxwellian plasma sheaths

International Nuclear Information System (INIS)

Haines, M.G.

1998-01-01

There is much experimental evidence that heat flux to divertor plates or to limiters is very asymmetric. For example, Lowry made measurements on poloidal limiters in JET, Stangeby and McCracken reported asymmetries in several experiments. In 1991 Haines considered the effects on the Child-Langmuir sheaths of having a net current flow. It was found that a sheath that receives more ions than electrons receives more energy flux than a sheath that receives more electrons than ions. We now extend the model to include for the electrons departures from a Maxwellian distribution arising from a net current flow, heat flow and thermoelectric effects in the scrape-off layer (SOL). It is envisaged that a net current flows in the SOL due to applied or induced electric fields, and is of a magnitude similar to that in the adjacent bulk plasma, though reduced due to the lower temperature in the SOL. We employ conventional linear transport theory eg. Braginskii, Epperlein and Haines in which the ions are a stationary Maxwellian. (orig.)

Diagnostic value of multi-slice spiral CT for atlantoaxial spine injuries in children

International Nuclear Information System (INIS)

Xia Chengde; Qin Hongwei; Li Junhong

2009-01-01

Objective: To evaluate the diagnostic value of multi-slice spiral CT (MSCT) for the atlantoaxial spine injuries in children. Methods: The CT findings of 21 cases with the atlantoaxial spine injuries in children were reviewed retrospectively. Results: Fractures of dens occurred in 4 cases, isolated atlantoaxial dislocation in 15 cases, subluxation of the C2/3 right vertebra facet in 1 and atlanto-occipital subluxation in 1. CT diagnosis was correct in all cases. And plain film diagnosis was correct ia 13. Conclusion: MSCT could clearly demonstrate the fractures and dislocations of the atlantoaxial spine injuries in children and correctly determine the type of the atlantoaxial spine injuries in children, MSCT is the modality of choice in diagnosis of the atlantoaxial spine injuries in children and should be performed routinely. (authors)

Brachial Plexopathy After Cervical Spine Surgery.

Science.gov (United States)

Than, Khoi D; Mummaneni, Praveen V; Smith, Zachary A; Hsu, Wellington K; Arnold, Paul M; Fehlings, Michael G; Mroz, Thomas E; Riew, K Daniel

2017-04-01

Retrospective, multicenter case-series study and literature review. To determine the prevalence of brachial plexopathy after cervical spine surgery and to review the literature to better understand the etiology and risk factors of brachial plexopathy after cervical spine surgery. A retrospective case-series study of 12 903 patients at 21 different sites was performed to analyze the prevalence of several different complications, including brachial plexopathy. A literature review of the US National Library of Medicine and the National Institutes of Health (PubMed) database was conducted to identify articles pertaining to brachial plexopathy following cervical spine surgery. In our total population of 12 903 patients, only 1 suffered from postoperative brachial plexopathy. The overall prevalence rate was thus 0.01%, but the prevalence rate at the site where this complication occurred was 0.07%. Previously reported risk factors for postoperative brachial plexopathy include age, anterior surgical procedures, and a diagnosis of ossification of the posterior longitudinal ligament. The condition can also be due to patient positioning during surgery, which can generally be detected via the use of intraoperative neuromonitoring. Brachial plexopathy following cervical spine surgery is rare and merits further study.

How to Patch Active Plasma and Collisionless Sheath: Practical Guide

International Nuclear Information System (INIS)

Kaganovich, Igor D.

2002-01-01

Most plasmas have a very thin sheath compared with the plasma dimension. This necessitates separate calculations of the plasma and sheath. The Bohm criterion provides the boundary condition for calculation of plasma profiles. To calculate sheath properties, a value of electric field at the plasma-sheath interface has to be specified in addition to the Bohm criterion. The value of the boundary electric field and robust procedure to approximately patch plasma and collisionless sheath with a very good accuracy are reported

Tuberculosis of the spine

International Nuclear Information System (INIS)

Psarras, H.; Faraj, J.; Gouliamos, A.; Kalovidouris, A.; Vlahos, L.; Papavassiliou, C.

1985-01-01

Two surgically proven cases of turberculous psoas abscess are presented. The common findings on CT were low-density paraspinal masses and extension of the lesions which followed the typical distribution of iliopsoas muscle in both cases. The skeletal findings from the spine are also discussed. Our cases indicate the complementary use of plain radiography and CT in the investigation of tuberculous spondylitis. (orig.) [de

EMS Adherence to a Pre-hospital Cervical Spine Clearance Protocol

Directory of Open Access Journals (Sweden)

Johnson, David

2001-10-01

Full Text Available Purpose: To determine the degree of adherence to a cervical spine (c-spine clearance protocol by pre-hospital Emergency Medical Services (EMS personnel by both self-assessment and receiving hospital assessment, to describe deviations from the protocol, and to determine if the rate of compliance by paramedic self-assessment differed from receiving hospital assessment. Methods: A retrospective sample of pre-hospital (consecutive series and receiving hospital (convenience sample assessments of the compliance with and appropriateness of c-spine immobilization. The c-spine clearance protocol was implemented for Orange County EMS just prior to the April-November 1999 data collection period. Results: We collected 396 pre-hospital and 162 receiving hospital data forms. From the pre-hospital data sheet. the percentage deviation from the protocol was 4.096 (16/396. Only one out of 16 cases that did not comply with the protocol was due to over immobilization (0.2%. The remaining 15 cases were under immobilized, according to protocol. Nine of the under immobilized cases (66% that should have been placed in c-spine precautions met physical assessment criteria in the protocol, while the other five cases met mechanism of injury criteria. The rate of deviations from protocol did not differ over time. The receiving hospital identified 8.0% (13/162; 6/16 over immobilized, 7/16 under immobilized of patients with deviations from the protocol; none was determined to have actual c-spine injury. Conclusion: The implementation of a pre-hospital c-spine clearance protocol in Orange County was associated with a moderate overall adherence rate (96% from the pre-hospital perspective, and 92% from the hospital perspective, p=.08 for the two evaluation methods. Most patients who deviated from protocol were under immobilized, but no c-spine injuries were missed. The rate of over immobilization was better than previously reported, implying a saving of resources.

C5 Palsy After Cervical Spine Surgery: A Multicenter Retrospective Review of 59 Cases.

Science.gov (United States)

Thompson, Sara E; Smith, Zachary A; Hsu, Wellington K; Nassr, Ahmad; Mroz, Thomas E; Fish, David E; Wang, Jeffrey C; Fehlings, Michael G; Tannoury, Chadi A; Tannoury, Tony; Tortolani, P Justin; Traynelis, Vincent C; Gokaslan, Ziya; Hilibrand, Alan S; Isaacs, Robert E; Mummaneni, Praveen V; Chou, Dean; Qureshi, Sheeraz A; Cho, Samuel K; Baird, Evan O; Sasso, Rick C; Arnold, Paul M; Buser, Zorica; Bydon, Mohamad; Clarke, Michelle J; De Giacomo, Anthony F; Derakhshan, Adeeb; Jobse, Bruce; Lord, Elizabeth L; Lubelski, Daniel; Massicotte, Eric M; Steinmetz, Michael P; Smith, Gabriel A; Pace, Jonathan; Corriveau, Mark; Lee, Sungho; Cha, Peter I; Chatterjee, Dhananjay; Gee, Erica L; Mayer, Erik N; McBride, Owen J; Roe, Allison K; Yanez, Marisa Y; Stroh, D Alex; Than, Khoi D; Riew, K Daniel

2017-04-01

A multicenter, retrospective review of C5 palsy after cervical spine surgery. Postoperative C5 palsy is a known complication of cervical decompressive spinal surgery. The goal of this study was to review the incidence, patient characteristics, and outcome of C5 palsy in patients undergoing cervical spine surgery. We conducted a multicenter, retrospective review of 13 946 patients across 21 centers who received cervical spine surgery (levels C2 to C7) between January 1, 2005, and December 31, 2011, inclusive. P values were calculated using 2-sample t test for continuous variables and χ 2 tests or Fisher exact tests for categorical variables. Of the 13 946 cases reviewed, 59 patients experienced a postoperative C5 palsy. The incidence rate across the 21 sites ranged from 0% to 2.5%. At most recent follow-up, 32 patients reported complete resolution of symptoms (54.2%), 15 had symptoms resolve with residual effects (25.4%), 10 patients did not recover (17.0%), and 2 were lost to follow-up (3.4%). C5 palsy occurred in all surgical approaches and across a variety of diagnoses. The majority of patients had full recovery or recovery with residual effects. This study represents the largest series of North American patients reviewed to date.

The feasibility of transradial laser atherectomy for chronic total occlusion using the 5 Fr sheath system

Directory of Open Access Journals (Sweden)

Khaled Sherif

2016-05-01

Full Text Available Objective. We present a case of chronic total occlusion (CTO approached with LASER endovascular intervention by radial artery approach using a 5 French sheath. Case report. A 57-year-old man presented to our hospital having had retrosternal chest pain for two days. Physical examination was normal at the time of presentation. The laboratory tests were within normal limits, including cardiac enzymes except the lipid panel which showed hypertriglyceridemia. The patient underwent a myocardial perfusion scintigraphy stress test that revealed inferior wall ischemia, with normal left ventricular ejection fraction. A 5-French vascular sheath was placed in the right radial artery. Selective coronary artery angiography was performed, which showed right coronary artery (RCA CTO. A 5-French JR4 guide catheter successfully engaged the RCA and Laser angioplasty was performed across the CTO into the RCA. A marked improvement of flow was evident thereafter. Conclusion. To best of our knowledge this is the first case report showing the feasibility of laser atherectomy using the 5 French sheath system in a coronary arterial CTO.

Plasma sheath in non-Maxwellian plasma

International Nuclear Information System (INIS)

Shimizu, Takuo; Horigome, Takashi

1992-01-01

Reviewing many theoretical and experimental works on the electron-energy distributions (EEDF) of various plasmas, we point out that many plasmas have EEDF of non-Maxwellian in shape. Therefore, the recent treatment of plasma sheath using the Maxwell-Boltzmann distribution approximation should be improved. To do this, we have adopted Rutcher's standard distribution as a generalized form in place of the traditional Maxwellian, and found that the minimum energy of ions entering the sheath edge (Bohm's criterion) varies largely, and have also shown the variation of Debye length with the shape of EEDF. The length is the most important parameter to proceed with more detailed analysis on plasma-sheaths, and also to control them in the future. (author)

Theory of the Electron Sheath and Presheath

Science.gov (United States)

Scheiner, Brett; Baalrud, Scott; Yee, Benjamin; Hopkins, Matthew; Barnat, Edward

2015-09-01

Electron sheaths are commonly found near Langmuir probes collecting the electron saturation current. The common assumption is that the probe collects the random flux of electrons incident on the sheath, which tacitly implies that there is no electron presheath and that the flux collected is due to a velocity space truncation of the velocity distribution function (VDF). This work provides a dedicated theory of electron sheaths, which suggests that electron sheaths are not so simple. Motivated by VDFs observed in recent Particle-In-Cell (PIC) simulations, we develop a 1D model for the electron sheath and presheath. In the model, under low temperature plasma conditions, an electron pressure gradient accelerates electrons in the presheath to a flow velocity that exceeds the electron thermal speed at the sheath edge. This pressure gradient allows the generation of large flows compared to those that would be generated by the electric field alone. It is due to this pressure gradient that the electron presheath extends much further into the plasma (nominally by a factor of √{mi /me }) than an analogous ion presheath. Results of the model are compared with PIC simulations. This work was supported by the Office of Fusion Energy Science at the U.S. Department of Energy under contract DE-AC04-94SL85000 and by the Office of Science Graduate Student Research (SCGSR) program under Contract Number DE-AC05-06OR23100.

Anode sheath in Hall thrusters

International Nuclear Information System (INIS)

Dorf, L.; Semenov, V.; Raitses, Y.

2003-01-01

A set of hydrodynamic equations is used to describe quasineutral plasma in ionization and acceleration regions of a Hall thruster. The electron distribution function and Poisson equation are invoked for description of a near-anode region. Numerical solutions suggest that steady-state operation of a Hall thruster can be achieved at different anode sheath regimes. It is shown that the anode sheath depends on the thruster operating conditions, namely the discharge voltage and the mass flow rate

Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

Science.gov (United States)

Kunoh, Tatsuki; Hashimoto, Hideki; McFarlane, Ian R.; Hayashi, Naoaki; Suzuki, Tomoko; Taketa, Eisuke; Tamura, Katsunori; Takano, Mikio; El-Naggar, Mohamed Y.; Kunoh, Hitoshi; Takada, Jun

2016-01-01

Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II) to Fe(III) and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II) concentrations, Fe(III) precipitates visibly formed immediately after addition of Fe(II) to the medium, suggesting prompt abiotic oxidation of Fe(II) to Fe(III). Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III) was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II) medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter), while those in the Fe(III) medium were composed of large, aggregated particles (≥3 µm diameter) with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved) of Fe encrustation of the Leptothrix sheaths. PMID:27271677

Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

Directory of Open Access Journals (Sweden)

Tatsuki Kunoh

2016-06-01

Full Text Available Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II to Fe(III and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II concentrations, Fe(III precipitates visibly formed immediately after addition of Fe(II to the medium, suggesting prompt abiotic oxidation of Fe(II to Fe(III. Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter, while those in the Fe(III medium were composed of large, aggregated particles (≥3 µm diameter with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved of Fe encrustation of the Leptothrix sheaths.

A Novel Technique Using a Protection Filter During Fibrin Sheath Removal for Implanted Venous Access Device Dysfunction

Energy Technology Data Exchange (ETDEWEB)

Sotiriadis, Charalampos; Hajdu, Steven David [University Hospital of Lausanne, Cardiothoracic and Vascular Unit, Department of Radiology (Switzerland); Degrauwe, Sophie [University Hospital of Lausanne, Department of Cardiology (Switzerland); Barras, Heloise; Qanadli, Salah Dine, E-mail: salah.qanadli@chuv.ch [University Hospital of Lausanne, Cardiothoracic and Vascular Unit, Department of Radiology (Switzerland)

2016-08-15

With the increased use of implanted venous access devices (IVADs) for continuous long-term venous access, several techniques such as percutaneous endovascular fibrin sheath removal, have been described, to maintain catheter function. Most standard techniques do not capture the stripped fibrin sheath, which is subsequently released in the pulmonary circulation and may lead to symptomatic pulmonary embolism. The presented case describes an endovascular technique which includes stripping, capture, and removal of fibrin sheath using a novel filter device. A 64-year-old woman presented with IVAD dysfunction. Stripping was performed using a co-axial snare to the filter to capture the fibrin sheath. The captured fragment was subsequently removed for visual and pathological verification. No immediate complication was observed and the patient was discharged the day of the procedure.

Intramedullary capillary hemangioma of the thoracic spine: case report and review of the literature

Directory of Open Access Journals (Sweden)

Paul Santiago

2009-07-01

Full Text Available Capillary hemangiomas are benign vascular neoplasms. When associated with the spine, these growths frequently involve the vertebral body, but rarely have they been reported to occur as intradural lesions, while even more rarely occurring in a true intramedullary location. We report a rare case of an intrame-dullary capillary hemangioma of the thoracic spinal cord and a review of the literature.

Tophaceous gout in the cervical spine

Energy Technology Data Exchange (ETDEWEB)

Cabot, Jonathan [Royal Adelaide Hospital, Department of Orthopaedic Surgery, Adelaide, South Australia (Australia); Mosel, Leigh; Kong, Andrew; Hayward, Mike [Flinders Medical Centre, Department of Medical Imaging, Bedford Park, South Australia (Australia)

2005-12-01

Gout is a common metabolic disorder typically affecting the distal joints of the appendicular skeleton. Involvement of the axial skeleton, particularly the facet joints and posterior column of the cervical spine, is rare. This case report highlights such a presentation in a 76-year old female who presented with cervical spine pain following a fall. Her radiological findings were suggestive of a destructive metastatic process. Histological diagnosis confirmed tophaceous gout. (orig.)

Tophaceous gout in the cervical spine

International Nuclear Information System (INIS)

Cabot, Jonathan; Mosel, Leigh; Kong, Andrew; Hayward, Mike

2005-01-01

Gout is a common metabolic disorder typically affecting the distal joints of the appendicular skeleton. Involvement of the axial skeleton, particularly the facet joints and posterior column of the cervical spine, is rare. This case report highlights such a presentation in a 76-year old female who presented with cervical spine pain following a fall. Her radiological findings were suggestive of a destructive metastatic process. Histological diagnosis confirmed tophaceous gout. (orig.)

Child–Langmuir law applicability for a cathode sheath description of glow discharge in hydrogen

International Nuclear Information System (INIS)

Lisovskiy, V A; Artushenko, K P; Yegorenkov, V D

2016-01-01

The present paper reveals that the Child-Langmuir law version with the constant ion mobility has to be applied for the cathode sheath description of the glow discharge in hydrogen. Using the analytical model we demonstrate that even in a high electric field the constant mobility law version rather than that for the constant ion mean free path has to hold in the case of impeded charge exchange and the dominant effect of polarization forces on the ion motion through the cathode sheath. (paper)

Effect of two-temperature electrons distribution on an electrostatic plasma sheath

International Nuclear Information System (INIS)

Ou, Jing; Xiang, Nong; Gan, Chunyun; Yang, Jinhong

2013-01-01

A magnetized collisionless plasma sheath containing two-temperature electrons is studied using a one-dimensional model in which the low-temperature electrons are described by Maxwellian distribution (MD) and high-temperature electrons are described by truncated Maxwellian distribution (TMD). Based on the ion wave approach, a modified sheath criterion including effect of TMD caused by high-temperature electrons energy above the sheath potential energy is established theoretically. The model is also used to investigate numerically the sheath structure and energy flux to the wall for plasmas parameters of an open divertor tokamak-like. Our results show that the profiles of the sheath potential, two-temperature electrons and ions densities, high-temperature electrons and ions velocities as well as the energy flux to the wall depend on the high-temperature electrons concentration, temperature, and velocity distribution function associated with sheath potential. In addition, the results obtained in the high-temperature electrons with TMD as well as with MD sheaths are compared for the different sheath potential

A suitable boundary condition for bounded plasma simulation without sheath resolution

International Nuclear Information System (INIS)

Parker, S.E.; Procassini, R.J.; Birdsall, C.K.; Cohen, B.I.

1993-01-01

We have developed a technique that allows for a sheath boundary layer without having to resolve the inherently small space and time scales of the sheath region. We refer to this technique as the logical sheath boundary condition. This boundary condition, when incorporated into a direct-implicit particle code, permits large space- and time-scale simulations of bounded systems, which would otherwise be impractical on current supercomputers. The lack of resolution of the collector sheath potential drop obtained from conventional implicit simulations at moderate values of ω pe Δt and Δz/λ De provides the motivation for the development of the logical sheath boundary condition. The algorithm for use of the logical sheath boundary condition in a particle simulation is presented. Results from simulations which use the logical sheath boundary condition are shown to compare reasonably well with those from an analytic theory and simulations in which the sheath is resolved

Epiretinal proliferation in lamellar macular holes and full-thickness macular holes: clinical and surgical findings.

Science.gov (United States)

Lai, Tso-Ting; Chen, San-Ni; Yang, Chung-May

2016-04-01

To report the clinical findings and surgical outcomes of lamellar macular holes (LMH) with or without lamellar hole-associated epiretinal proliferation (LHEP), and those of full-thickness macular holes (FTMH) presenting with LHEP. From 2009 to 2013, consecutive cases of surgically treated LMH, and all FTMH cases with LHEP were reviewed, given a follow-up time over 1 year. In the LMH group (43 cases), those with LHEP (19 cases) had significantly thinner bases and larger openings than those without (24 cases). The rate of disrupted IS/OS line was higher in the LHEP subgroup preoperatively (68.4 % vs 37.5 %), but similar between subgroups postoperatively (36.8 % and 33.3 %). The preoperative and postoperative visual acuity showed no significant difference between two subgroups. In the FTMH group (13 cases), the average hole size was 219.2 ± 92.1 μm. Permanent or transient spontaneous hole closure was noted in 69.2 % of cases. An intact IS-OS line was found in only 23 % of cases at the final follow-up. In the LMH group, LHEP was associated with a more severe defect but didn't affect surgical outcomes. In the FTMH group, spontaneous hole closure was frequently noted. Despite small holes, disruption of IS-OS line was common after hole closure.

Accuracy and complications of CT-guided core needle biopsy of peripheral nerve sheath tumours

Energy Technology Data Exchange (ETDEWEB)

Pianta, Marcus; Chock, Eric; Schlicht, Stephen [St Vincent' s Hospital, Fitzroy, VIC (Australia); McCombe, David [St Vincent' s Hospital and Victorian Hand Surgery Associates, Victoria (Australia)

2015-09-15

This single-centre study retrospectively reviews the complications in patients that have occurred following peripheral nerve sheath tumour biopsy, and assesses whether there is an association with biopsy technique or underlying lesion characteristics. 41 consecutive core needle biopsies of proven peripheral nerve sheath tumours over a 2-year period in a tertiary teaching hospital were reviewed. Patient demographics and symptoms, tumour characteristics and radiological appearances were recorded. Biopsy and surgical histology were correlated, and post-biopsy and surgical complications analyzed. 41 biopsies were performed in 38 patients. 68 % schwannomas, 24 % neurofibromas and 7 % malignant peripheral nerve sheath tumours. Biopsy histology correlated with surgery in all cases. 71 % of lesions were surgically excised. 60 % of patients reported pain related to their lesion. Following the biopsy, 12 % reported increased pain, which resolved in all cases. Pain exacerbation was noted in tumours smaller in size, more superficial and in closer proximity of the biopsy needle tip to the traversing nerve. Number of biopsy needle passes was not associated with an increased incidence of procedure-related pain. Core biopsy of a suspected peripheral nerve sheath tumour may be performed safely before excisional surgery to confirm lesion histology and assist prognosis. There is excellent correlation between core biopsy and excised surgical specimen histology. The most common complication of pain exacerbation is seen in a minority and is temporary, and more likely with smaller, more superficial lesions and a closer needle-tip to traversing nerve distance during biopsy. (orig.)

Accuracy and complications of CT-guided core needle biopsy of peripheral nerve sheath tumours

International Nuclear Information System (INIS)

Pianta, Marcus; Chock, Eric; Schlicht, Stephen; McCombe, David

2015-01-01

This single-centre study retrospectively reviews the complications in patients that have occurred following peripheral nerve sheath tumour biopsy, and assesses whether there is an association with biopsy technique or underlying lesion characteristics. 41 consecutive core needle biopsies of proven peripheral nerve sheath tumours over a 2-year period in a tertiary teaching hospital were reviewed. Patient demographics and symptoms, tumour characteristics and radiological appearances were recorded. Biopsy and surgical histology were correlated, and post-biopsy and surgical complications analyzed. 41 biopsies were performed in 38 patients. 68 % schwannomas, 24 % neurofibromas and 7 % malignant peripheral nerve sheath tumours. Biopsy histology correlated with surgery in all cases. 71 % of lesions were surgically excised. 60 % of patients reported pain related to their lesion. Following the biopsy, 12 % reported increased pain, which resolved in all cases. Pain exacerbation was noted in tumours smaller in size, more superficial and in closer proximity of the biopsy needle tip to the traversing nerve. Number of biopsy needle passes was not associated with an increased incidence of procedure-related pain. Core biopsy of a suspected peripheral nerve sheath tumour may be performed safely before excisional surgery to confirm lesion histology and assist prognosis. There is excellent correlation between core biopsy and excised surgical specimen histology. The most common complication of pain exacerbation is seen in a minority and is temporary, and more likely with smaller, more superficial lesions and a closer needle-tip to traversing nerve distance during biopsy. (orig.)

Thoracic Duct Injury Following Cervical Spine Surgery: A Multicenter Retrospective Review

OpenAIRE

Derakhshan, Adeeb; Lubelski, Daniel; Steinmetz, Michael P.; Corriveau, Mark; Lee, Sungho; Pace, Jonathan R.; Smith, Gabriel A.; Gokaslan, Ziya; Bydon, Mohamad; Arnold, Paul M.; Fehlings, Michael G.; Riew, K. Daniel; Mroz, Thomas E.

2017-01-01

Study Design: Multicenter retrospective case series. Objective: To determine the rate of thoracic duct injury during cervical spine operations. Methods: A retrospective case series study was conducted among 21 high-volume surgical centers to identify instances of thoracic duct injury during anterior cervical spine surgery. Staff at each center abstracted data for each identified case into case report forms. All case report forms were collected by the AOSpine North America Clinical Research Ne...

Electrospinning jet behaviors under the constraints of a sheath gas

Directory of Open Access Journals (Sweden)

Yang Zhao

2016-11-01

Full Text Available Increasing the ejection efficiency and uniformity of nanofibers is the key to applications of electrospinning technology. In this work, a novel electrospinning spinneret with a sheath gas passageway is designed. The frictional resistance that stems from the sheath gas provides additional stretching and restriction forces on the jet. The sheath gas also reduces interference and enhances the stability of the charged jet. A bead-on-strain simulation model is built up to determine the constraint effects of the sheath gas. Simulation results show that the sheath gas decreases the motion area and increases the stretching ratio of the liquid jet. The stretching force from the sheath gas decreases the diameter and increases the uniformity of the nanofiber. As the gas pressure increases from 0 kPa to 50 kPa, the critical voltage of the jet ejection decreases from 8.4 kV to 2.5 kV, the diameter of the nanofiber deposition zone decreases from 40 cm to 10 cm, and the diameter of the nanofibers decreases from 557.97 nm to 277.73 nm. The uniformity of nanofibers can be improved significantly using a sheath gas. The sheath gas contributes to the rapid deposition of a uniform nanofibrous membrane and the industrial applications of electrospinning.

Use of guiding sheaths in peroral fluoroscopic gastroduodenal stent placement

International Nuclear Information System (INIS)

Bae, Jae-Ik; Shin, Ji Hoon; Song, Ho-Young; Yoon, Chang Jin; Nam, Deok Ho; Choi, Won-Chan; Lim, Jin-Oh

2005-01-01

Our purpose was to assess the safety and usefulness of guiding sheaths in peroral fluoroscopic gastroduodenal stent placement. Two types of guiding sheath were made from straight polytetrafluoroethylene tubes. Type A was 80 cm in length, 4 mm in outer diameter and 3 mm in inner diameter. Type B was 70 cm in length, 6 mm in outer diameter and 5 mm in inner diameter. The type A sheath was used in 18 patients in whom a catheter-guide wire combination failed to pass through a stricture. The type B sheath was used in 22 patients in whom a stent delivery system failed to pass through the stricture due to loop formation within the gastric lumen. The overall success rate for guiding a catheter-guide wire through a stricture after using the type A sheath was 89%. The overall success rate for passing a stent delivery system through a stricture after using the type B sheath was 100%. All procedures were tolerated by the patients without any significant complications. The guiding sheaths were safe and useful in peroral fluoroscopic gastroduodenal stent placement. (orig.)

Myositis Ossificans Progressiva in the Whole Spine: A Case Report

Directory of Open Access Journals (Sweden)

Ebrahim Ghayem Hasankhani

2018-02-01

Full Text Available Myositis ossificans progressiva is a rare inherited disease characterized by progressive ectopic ossifications associated with thumb and big toe anomalies. Ossification usually progresses from central to the peripheral, proximal to distal, cranial to caudal, and from dorsal to ventral directions and leading to activity limitation, significant eating disability, recurrent pulmonary infection, and atelectasis. In this report, we present a 7-year-old boy with a total spine stiffness (wooden spine seriously limited his activity of daily living.

Experimental investigation of plasma sheaths in magnetic mirror and cusp configurations

Science.gov (United States)

Jiang, Zhengqi; Wei, Zi-an; Ma, J. X.

2017-11-01

Sheath structures near a metal plate in a magnetized plasma were experimentally investigated in magnetic mirror and cusp configurations. Plasma parameters and the sheath potential distributions were probed by a planar and an emissive probe, respectively. The measured sheath profiles in the mirror configuration show that the sheath thickness first decreases and then increases when the magnetic strength is raised. A magnetic flux-tube model was used to explain this result. In the cusp configuration, the measured sheath thickness decreases with the increase of the coil current creating the magnetic cusp. However, when normalized by the electron Debye length, the dependence of the sheath thickness on the coil current is reversed.

Behavior of collisional sheath in electronegative plasma with q-nonextensive electron distribution

Science.gov (United States)

Borgohain, Dima Rani; Saharia, K.

2018-03-01

Electronegative plasma sheath is addressed in a collisional unmagnetized plasma consisting of q-nonextensive electrons, Boltzmann distributed negative ions and cold fluid positive ions. Considering the positive ion-neutral collisions and ignoring the effects of ionization and collisions between negative species and positive ions (neutrals), a modified Bohm sheath criterion and hence floating potential are derived by using multifluid model. Using the modified Bohm sheath criterion, the sheath characteristics such as spatial profiles of density, potential and net space charge density have been numerically investigated. It is found that increasing values of q-nonextensivity, electronegativity and collisionality lead to a decrease of the sheath thickness and an increase of the sheath potential and the net space charge density. With increasing values of the electron temperature to negative ion temperature ratio, the sheath thickness increases and the sheath potential as well as the net space charge density in the sheath region decreases.

Thoracic Duct Injury Following Cervical Spine Surgery: A Multicenter Retrospective Review.

Science.gov (United States)

Derakhshan, Adeeb; Lubelski, Daniel; Steinmetz, Michael P; Corriveau, Mark; Lee, Sungho; Pace, Jonathan R; Smith, Gabriel A; Gokaslan, Ziya; Bydon, Mohamad; Arnold, Paul M; Fehlings, Michael G; Riew, K Daniel; Mroz, Thomas E

2017-04-01

Multicenter retrospective case series. To determine the rate of thoracic duct injury during cervical spine operations. A retrospective case series study was conducted among 21 high-volume surgical centers to identify instances of thoracic duct injury during anterior cervical spine surgery. Staff at each center abstracted data for each identified case into case report forms. All case report forms were collected by the AOSpine North America Clinical Research Network Methodological Core for data processing, cleaning, and analysis. Of a total of 9591 patients reviewed that underwent cervical spine surgery, 2 (0.02%) incurred iatrogenic injury to the thoracic duct. Both patients underwent a left-sided anterior cervical discectomy and fusion. The interruption of the thoracic duct was addressed intraoperatively in one patient with no residual postoperative effects. The second individual developed a chylous fluid collection approximately 2 months after the operation that required drainage via needle aspiration. Damage to the thoracic duct during cervical spine surgery is a relatively rare occurrence. Rapid identification of the disruption of this lymphatic vessel is critical to minimize deleterious effects of this complication.

Addition of rectus sheath relaxation incisions to emergency midline laparotomy for peritonitis to prevent fascial dehiscence.

Science.gov (United States)

Marwah, Sanjay; Marwah, Nisha; Singh, Mandeep; Kapoor, Ajay; Karwasra, Rajender Kumar

2005-02-01

The incidence of fascial dehiscence and incisional hernia after two methods for abdominal wound closure (rectus sheath relaxation incisions and conventional mass closure) was studied in a randomized prospective clinical trial in a consecutive series of 100 patients undergoing midline laparotomy for peritonitis. The two groups were well matched for etiologies of peritonitis, the surgical procedures performed, and the presence of known risk factors for fascial dehiscence. Fifty patients each were randomized either to the conventional continuous mass closure procedure or the rectus sheath relaxation incision technique (designed to increase wound elasticity and decrease tension in the suture line) using identical polypropylene sutures. The incidence of postoperative complications such as duration of ileus, chest infection, and wound infection were not statistically different between the two groups. The intensity of postoperative pain in the rectus sheath relaxation incision group was significantly less. The incidence of wound hematoma was significantly increased in the rectus sheath relaxation incision group. The incidences of fascial dehiscence (16% vs,28%; p cases of peritonitis using the rectus sheath relaxation technique is safe and less painful, provides increased wound elasticity and decreased tension on the suture line, and significantly decreases the incidence of wound dehiscence.

ALINE: A device dedicated to understanding radio-frequency sheaths

Directory of Open Access Journals (Sweden)

S. Devaux

2017-08-01

Full Text Available In fusion devices, radiofrequency (RF antennas are used for heating the plasma. Those antennas and the plasma interact with each other through the so-called RF sheaths, layers of plasma where the quasi-neutrality breaks down and large electric fields arise. Among the effects of RF sheaths, there is the enhancement of the particles and energy fluxes toward the surface of the antenna, which in turn generate hot spots and release impurities, which are both deleterious for plasma operations. RF sheaths comprehension stumbles on the difficulty to achieve in situ measurements of the sheath properties, as scrape-off layer plasmas are a harsh environment. The very goal of the ALINE device is to tackle this issue and to fulfil the blank between numerical simulations and full-scale experiment by providing measurements within the RF sheaths in a controlled environment. In this paper we report on the latest experimental results from ALINE, in which a cylindrical Langmuir probe mounted on a remotely controlled and programmable arm allows for plasma characterizations in the three dimensions of space around the stainless steel antenna, including the sheath. We present a series of density and potential profiles and three dimension (3D maps in the plasma surrounding a stainless-steel RF antenna as well as in the sheath itself, for unmagnetized and magnetized plasmas.

In vivo engineering of a functional tendon sheath in a hen model.

Science.gov (United States)

Xu, Liang; Cao, Dejun; Liu, Wei; Zhou, Guangdong; Zhang, Wen Jie; Cao, Yilin

2010-05-01

Repair of injured tendon sheath remains a major challenge and this study explored the possibility of in vivo reconstruction of a tendon sheath with tendon sheath derived cells and polyglycolic acid (PGA) fibers in a Leghorn hen model. Total 55 Leghorn hens with a 1cm tendon sheath defect created in the left middle toe of each animal were randomly assigned into: (1) experimental group (n=19) that received a cell-PGA construct; (2) scaffold control group (n=18) that received a cell-free PGA scaffold; (3) blank control group (n=18) with the defect untreated. Tendon sheath cells were isolated, in vitro expanded, and seeded onto PGA scaffolds. After in vitro culture for 7 days, the constructs were in vivo implanted to repair the sheath defects. Alcian blue staining confirmed the ability of cultured cells to produce specific matrices containing acidic carboxyl mucopolysaccharide (mainly hyaluronic acid). In addition, the engineered sheath formed a relatively mature structure at 12 weeks post-surgery, which was similar to that of native counterpart, including a smooth inner surface, a well-developed sheath histological structure with a clear space between the tendon and the engineered sheath. More importantly, Work of Flexion assay revealed that the tendons needed less power consumption to glide inside the engineered sheath when compared to the tendons which were surrounded by scar-repaired tissues, indicating that the engineered sheaths had gained the function to a certain extent of preventing tendon adhesion. Taken together, these results suggest that tendon sheaths that are functionally and structurally similar to native sheaths are possible to be engineered in vivo using tendon sheath cells and PGA scaffolds. Copyright 2010 Elsevier Ltd. All rights reserved.

微小后组脑神经鞘瘤七例报告%Clinical study of 7 cases of missed diagnosis of micro-tumor of cranial nerve sheath and literature review

Institute of Scientific and Technical Information of China (English)

赵奎明; 杨冬; 袁越; 张哲; 张黎; 于炎冰

2012-01-01

目的 分析临床罕见的微小后组脑神经鞘瘤的临床特点,探讨其临床症状、早期诊断、手术方法和疗效.方法 回顾性分析1999年9月至2009年8月我院治疗的7例临床漏诊的微小后组脑神经鞘瘤病例,总结其临床症状、早期诊断、手术方法及疗效,并结合文献进行分析.结果 本组病例中共有舌咽神经鞘瘤5例、迷走神经鞘瘤1例、舌下神经鞘瘤1例.肿瘤均完全切除.术后并发症包括一过性轻度面瘫、声音嘶哑2例、吞咽困难1例.结论 对出现后组脑神经症状的患者应考虑到后组脑神经鞘瘤的可能,尽快明确诊断并积极手术治疗可获得优良疗效,有利于患者的治疗和康复.%Objective To analyze the clinical characteristics of the rare micro-lower cranial nerve sheath tumor,and investigate the clinical symptoms,early treatment options,as well as surgical elements/effectiveness.Methods Seven missed diagnoses of micro-lower cranial nerve sheath tumor admitted to our department from October 1999 to August 2009 were analyzed retrospectively.Diagnosis,clinical characteristics,early treatment options,surgical elements and effectiveness were summarized and analyzed in combined with literature review.Results In this group of patients,there were 5 glossopharyngeal nerve sheath tumors,1 vagus nerve sheath tumor and 1 hypoglossal nerve sheath tumor.Total resections were achieved in all of the patients.Postoperative complications included 1 case of transient mild paralysis,2 cases of hoarseness and 1 case of dysphagia.Conclusions For patient with lower cranial nerve symptoms,nerve sheath tumors should be taken into consideration.Early diagnosis and effective surgery will contribute to patient's treatment and rehabilitation.

Intrapontine malignant nerve sheath tumor

DEFF Research Database (Denmark)

Kozić, Dusko; Nagulić, Mirjana; Samardzić, Miroslav

2008-01-01

. On pathological examination, the neoplasm appeared to be an intrapontine nerve sheath tumor originating most likely from the intrapontine segment of one of the cranial nerve fibres. The tumor showed exophytic growth, with consequent spread to adjacent subaracnoid space. MR spectroscopy revealed the presence......The primary source of malignant intracerebral nerve sheath tumors is still unclear We report the imaging and MR spectroscopic findings in a 39-year-old man with a very rare brain stem tumor MR examination revealed the presence of intraaxial brain stem tumor with a partial exophytic growth...

The Child-Langmuir law and analytical theory of collisionless to collision-dominated sheaths

International Nuclear Information System (INIS)

Benilov, M S

2009-01-01

This paper is concerned with summarizing simple analytical models of space-charge sheaths and tracing their relation to the Child-Langmuir model of an ion sheath. The topics discussed include the Child-Langmuir law and model of a collisionless ion sheath, the Mott-Gurney law and model of a collision-dominated ion sheath, the Bohm model of a collisionless ion-electron sheath, the Su-Lam-Cohen model of a collision-dominated ion-electron sheath, ion sheaths with arbitrary collisionality, high-accuracy boundary conditions for the Child-Langmuir and Mott-Gurney models of an ion sheath and the mathematical sense of Child-Langmuir type models of an ion sheath from the point of view of modern theoretical physics.

The many facets of pulsed neutron cased-hole logging

Energy Technology Data Exchange (ETDEWEB)

Albertin, I.; Darling, H.; Mahdavi, M.; Plasek, R. [Schlumberger Houston Product Center, Sugarland, TX (United States); Cedeno, I. [City Investing Company Ltd., Quito (Ecuador); Hemingway, J.; Richter, P. [GeoQuest, Bakersfield, CA (United States); Markley, M. [Schlumberger, Bogota (Colombia); Olesen, J.R. [Schlumberger, Beijing (China); Roscoe, B. [Schlumberger-Doll Research, Ridgefield, CT (United States); Zeng, Wenchong [Shengli Petroleum Administration Bureau, China Petroleum Corporation, Beijing (China)

1996-12-31

The RST Reservoir Saturation Tool, which bombards formations with neutrons and detects gamma rays from the resulting interactions, is rapidly becoming a complete stand-alone, cased-hole evaluation service. Measurements like elemental analysis, thermal decay times, porosity evaluation and production analysis help reservoir engineers locate bypassed oil, detect waterflood fronts, fine-tune formation evaluations and monitor production profiles. 19 figs., 12 refs.

Primary dorsal spine primitive neuroectodermal tumor in an adult patient: Case report and literature review

Directory of Open Access Journals (Sweden)

Satyashiva Munjal

2017-01-01

Full Text Available Primary spinal primitive neuroectodermal tumor (psPNET is a rare entity with few cases reported in literature. We report a case of a 50-year-old female who presented to us with paraplegia and was diagnosed with extradural dorsal spine psPNET. The diagnosis was not suspected at presentation or on radiology but was established on histopathological examination. It is important to distinguish it from central nervous system primitive neuroectodermal tumors and from other spinal tumors since it follows a different clinical course and therapeutic outcome.

What is the size of a floating sheath? An answer

Science.gov (United States)

Voigt, Farina; Naggary, Schabnam; Brinkmann, Ralf Peter

2016-09-01

The formation of a non-neutral boundary sheath in front of material surfaces is universal plasma phenomenon. Despite several decades of research, however, not all related issues are fully clarified. In a recent paper, Chabert pointed out that this lack of clarity applies even to the seemingly innocuous question ``What the size of a floating sheath?'' This contribution attempts to provide an answer that is not arbitrary: The size of a floating sheath is defined as the plate separation of an equivalent parallel plate capacitor. The consequences of the definition are explored with the help of a self-consistent sheath model, and a comparison is made with other sheath size definitions. Deutsche Forschungsgemeinschaft within SFB TR 87.

Effects of emitted electron temperature on the plasma sheath

International Nuclear Information System (INIS)

Sheehan, J. P.; Kaganovich, I. D.; Wang, H.; Raitses, Y.; Sydorenko, D.; Hershkowitz, N.

2014-01-01

It has long been known that electron emission from a surface significantly affects the sheath surrounding that surface. Typical fluid theory of a planar sheath with emitted electrons assumes that the plasma electrons follow the Boltzmann relation and the emitted electrons are emitted with zero energy and predicts a potential drop of 1.03T e /e across the sheath in the floating condition. By considering the modified velocity distribution function caused by plasma electrons lost to the wall and the half-Maxwellian distribution of the emitted electrons, it is shown that ratio of plasma electron temperature to emitted electron temperature significantly affects the sheath potential when the plasma electron temperature is within an order of magnitude of the emitted electron temperature. When the plasma electron temperature equals the emitted electron temperature the emissive sheath potential goes to zero. One dimensional particle-in-cell simulations corroborate the predictions made by this theory. The effects of the addition of a monoenergetic electron beam to the Maxwellian plasma electrons were explored, showing that the emissive sheath potential is close to the beam energy only when the emitted electron flux is less than the beam flux

Malignant transformation in a hybrid schwannoma/perineurioma: Addition to the spectrum of a malignant peripheral nerve sheath tumor

Directory of Open Access Journals (Sweden)

Bharat Rekhi

2011-01-01

Full Text Available Benign nerve sheath tumors include schwannomas, neurofibromas and perineuriomas. The malignant counterpart of a nerve sheath tumor is designated as a malignant peripheral nerve sheath tumor (MPNST. Lately, benign nerve sheath tumors comprising more than one component have been described, including hybrid schwannomas/perineuriomas. However, malignant transformation in a hybrid schwannoma/perineurioma has not been documented so far. Herein, we present a rare case of a young adult male who presented with a soft tissue mass in his right thigh that was excised elsewhere and submitted to us for histopathological review. One of the tissue sections displayed histopathological features of a hybrid schwannoma/perineurioma, including alternate arrangement of benign schwann and perineurial cells, reinforced with S100-P and epithelial membrane antigen positivity, respectively, along with low MIB1 and negative p53 immunostaining. The other two tissue sections showed a spindly sarcomatous tumor that was immunohistochemically positive for S100-P, CD34, p53 and exhibited high MIB1 (30-40%. Diagnosis of a MPNST arising in a hybrid schwannoma/perineurioma was made. This unusual case forms yet another addition to the spectrum of a MPNST.

Sheath impedance effects in very high frequency plasma experiments

International Nuclear Information System (INIS)

Schwarzenbach, W.; Howling, A.A.; Fivaz, M.; Brunner, S.; Hollenstein, C.

1995-05-01

The frequency dependence (13.56 MHz to 70 MHz) of the ion energy distribution at the ground electrode was measured by mass spectrometry in a symmetrical capacitive argon discharge. Reduced sheath impedance at Very High Frequency allows high levels of plasma power and substrate ion flux whilst maintaining low levels of ion energy and electrode voltage. The lower limit of ion bombardment energy is fixed by the sheath floating potential at high frequency, in contrast to low frequencies where only the rf voltage amplitude is determinant. The capacitive sheaths are thinner at high frequencies which accentuates the high frequency reduction in sheath impedance. It is argued that the frequency dependence of sheath impedance is responsible for the principal characteristics of Very High Frequency plasmas. The measurements are summarised by simple physical descriptions and compared with a Particle-In-Cell simulation. (author) figs., tabs., refs

Genomic and Expression Profiling of Benign and Malignant Nerve Sheath Profiling of Benign and Malignant Nerve Sheath

Science.gov (United States)

2007-05-01

Benign and Malignant Nerve Sheath Tumors in Neurofibromatosis Patients PRINCIPAL INVESTIGATOR: Matt van de Rijn, M.D., Ph.D. Torsten...Annual 3. DATES COVERED 1 May 2006 –30 Apr 2007 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Genomic and Expression Profiling of Benign and Malignant Nerve...Award Number: DAMD17-03-1-0297 Title: Genomic and Expression Profiling of Benign and Malignant Nerve Sheath Tumors in Neurofibromatosis

Nondestructive testing of metallic sheath for internally cooled superconductor

International Nuclear Information System (INIS)

McClung, R.W.; Cook, K.V.; Dodd, C.V.; Smith, J.H.

1983-01-01

For quality assurance in the Oak Ridge National Laboratory Large Coil Program, we developed ultrasonic and eddy-current techniques to examine the JBK-75 alloy sheath for superconducting cable for a large magnet. Ultrasound was used to examine the strip before forming into the sheath, and eddy currents were used to examine the seam weld after the sheath had been formed around the cable

Adherence to Canadian C-Spine Rule in a regional hospital: a retrospective study of 406 cases.

Science.gov (United States)

Paxton, Mark; Heal, Clare F; Drobetz, Herwig

2012-10-01

Cervical spine radiography may be over-utilised in an emergency department setting. The Canadian C-Spine Rule has been developed to reduce unnecessary radiography. Our aim was to retrospectively determine the proportion of cervical spine radiographs requested through the emergency department for trauma patients that were clinically indicated, according to the Canadian C-Spine Rule. This was a cross-sectional survey conducted at a regional centre in Northern Queensland, Australia. All cervical spine radiographs for trauma, performed at the Mackay Base Hospital from 1 January 2009 to the 31 December 2009, were reviewed. The relevant patient charts were audited for evidence of indications for radiography. Of 406 patients in the study, 155 patients (38%) (95% confidence interval 33.3%, 42.7%) had cervical spine imaging performed that was not indicated according to the Canadian C-Spine Rule. None of these patients had a significant cervical spine injury on radiography. Applying the Canadian C-Spine Rule would have safely reduced the incidence of cervical spine radiography by 38%. This would also reduce costs, patient morbidity and radiation exposure. © 2012 The Authors. Journal of Medical Imaging and Radiation Oncology © 2012 The Royal Australian and New Zealand College of Radiologists.

Effects of fast monoenergetic electrons on the ion dynamics near the cathode in a pulsed direct current plasma sheath

International Nuclear Information System (INIS)

Sharifian, M.; Shokri, B.

2008-01-01

A detailed one-dimensional simulation of the ion dynamics of the plasma sheath near a substrate (cathode) in the presence of fast monoenergetic electrons has been carried out in this article. The sheath evolution is investigated by using a fluid model assuming that the ions, plasma electrons and monoenergetic, fast electrons act as three fluids (fluid approach). The effect of the density of fast electrons on the ion density, ion velocity, and ion energy near the cathode and the evolution of the sheath boundary in front of the cathode are separately explored. Also, the variation of the ion velocity and ion density at the vicinity of the cathode as a function of time is investigated in the absence and presence of the electron beam. Results indicate that the presence of fast electrons in the sheath causes significant change in the sheath thickness and therefore basically changes the ion velocity, ion density, and ion impact energy on the cathode compared to the absence of the electron beam case

Plasma Sheath Behavior in a Coaxial Discharge Device

International Nuclear Information System (INIS)

EL-Aragi, G.; Soliman, H.M.; Masoud, M.M.

2001-01-01

The behavior of the plasma sheath has been studied experimentally and theoretically for 3 kJ coaxial discharge device. The discharge takes place in argon gas with pressure of 0.8 mbar. The experiments are conducted with a 10 kV bank charging voltage, which corresponds to 110 kA peak discharge current with time period of 34 μs. The experimental investigations have been studied using a magnetic probes and a miniature Rogowsky coil. A snowplough model is used to drive an analytical solution of the plasma sheath behavior in axial direction. Measurements of radial distribution of plasma sheath current density J r at the muzzle, show that J r has the following relation, J r is proportional to r -1.1 . From the experimental results and theoretical calculations of axial distribution of azimuthal magnetic field induction and plasma sheath velocity, the inclination angle between the normal of the plasma sheath with the axial distance at any axial position is evaluated and it has approximately a constant value for most axial distances. Also, the axial motion of plasma sheath acceleration is estimated experimentally a max = 0.13 x 10 12 ' cm / s 2 at z = 11 cm and from theoretical calculations a max = 0.15 x 10 12 cm/ s 2 at max z = 1.6 cm. A comparison of the experimental results with the theoretical calculations, under the assumption of the snowplough model are not in agreement. (author)

Dynamic posterior stabilization for degenerative lumbar spine disease: a large consecutive case series with long-term follow-up by additional postal survey.

Science.gov (United States)

Greiner-Perth, R; Sellhast, N; Perler, G; Dietrich, D; Staub, L P; Röder, C

2016-08-01

Dynamic stabilization of the degenerated spine was invented to overcome the negative side effects of fusion surgery like adjacent segment degeneration. Amongst various different implants DSS(®) is a pedicle-based dynamic device for stabilizing the spine and preserving motion. Nearly no clinical data of the implant have been reported so far. The current analysis presents results from a single spine surgeon who has been using DSS(®) for the past 5 years and recorded all treatment and outcome data in the international Spine Tango registry. From the prospectively documented overall patient pool 436 cases treated with DSS(®) could be identified. The analysis was enhanced with a mailing of COMI patient questionnaires for generating longer-term follow-ups up to 4 years. 387 patients (189 male, 198 female; mean age 67.3 years) with degenerative lumbar spinal disease including degenerative spondylolisthesis (6.1 %) could be evaluated. The type of degeneration was mainly spinal stenosis (89.9 %). After a mean follow-up of 1.94 years, the COMI score and NRS back and leg pain improved significantly and to a clinically relevant extent. The postoperative trend analysis could not determine a relevant deterioration of these outcomes until 4 years postoperative. 10 patients were revised (2.6 %) and the implant was removed; in most cases, a fusion was performed. Another 5 cases (1.3 %) had an extension of the dynamic stabilization system to the adjacent level. 84.2 % of patients rated that the surgery had helped a lot or had helped. The results of this large consecutive series with a follow-up up to 4 years could demonstrate a good and stable clinical outcome after posterior dynamic stabilization with DSS(®). For degenerative diseases of the lumbar spine, this treatment seems to be a valid alternative to fusion surgery.

Age-Based Comparison of Human Dendritic Spine Structure Using Complete Three-Dimensional Reconstructions

Science.gov (United States)

Benavides-Piccione, Ruth; Fernaud-Espinosa, Isabel; Robles, Victor; Yuste, Rafael; DeFelipe, Javier

2013-01-01

Dendritic spines of pyramidal neurons are targets of most excitatory synapses in the cerebral cortex. Recent evidence suggests that the morphology of the dendritic spine could determine its synaptic strength and learning rules. However, unfortunately, there are scant data available regarding the detailed morphology of these structures for the human cerebral cortex. In the present study, we analyzed over 8900 individual dendritic spines that were completely 3D reconstructed along the length of apical and basal dendrites of layer III pyramidal neurons in the cingulate cortex of 2 male humans (aged 40 and 85 years old), using intracellular injections of Lucifer Yellow in fixed tissue. We assembled a large, quantitative database, which revealed a major reduction in spine densities in the aged case. Specifically, small and short spines of basal dendrites and long spines of apical dendrites were lost, regardless of the distance from the soma. Given the age difference between the cases, our results suggest selective alterations in spines with aging in humans and indicate that the spine volume and length are regulated by different biological mechanisms. PMID:22710613

Stability of the Tonks–Langmuir discharge pre-sheath

Energy Technology Data Exchange (ETDEWEB)

Tskhakaya, D. D. [Fusion@ÖAW, Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna (Austria); Kos, L. [LECAD Laboratory, Faculty of Mechanical Engineering, University of Ljubljana, SI-1000 Ljubljana (Slovenia); Tskhakaya, D. [Fusion@ÖAW, Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna (Austria); Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria)

2016-03-15

The article formulates the stability problem of the plasma sheath in the Tonks–Langmuir discharge. Using the kinetic description of the ion gas, i.e., the stability of the potential shape in the quasi-neutral pre-sheath regarding the high and low frequency, the perturbations are investigated. The electrons are assumed to be Maxwell–Boltzmann distributed. Regarding high-frequency perturbations, the pre-sheath is shown to be stable. The stability problem regarding low-frequency perturbations can be reduced to an analysis of the “diffusion like” equation, which results in the instability of the potential distribution in the pre-sheath. By means of the Particle in Cell simulations, also the nonlinear stage of low frequency oscillations is investigated. Comparing the figure obtained with the figure for linear stage, one can find obvious similarity in the spatial-temporal behavior of the potential.

An analytical investigation: Effect of solar wind on lunar photoelectron sheath

Science.gov (United States)

Mishra, S. K.; Misra, Shikha

2018-02-01

The formation of a photoelectron sheath over the lunar surface and subsequent dust levitation, under the influence of solar wind plasma and continuous solar radiation, has been analytically investigated. The photoelectron sheath characteristics have been evaluated using the Poisson equation configured with population density contributions from half Fermi-Dirac distribution of the photoemitted electrons and simplified Maxwellian statistics of solar wind plasma; as a consequence, altitude profiles for electric potential, electric field, and population density within the photoelectron sheath have been derived. The expression for the accretion rate of sheath electrons over the levitated spherical particles using anisotropic photoelectron flux has been derived, which has been further utilized to characterize the charging of levitating fine particles in the lunar sheath along with other constituent photoemission and solar wind fluxes. This estimate of particle charge has been further manifested with lunar sheath characteristics to evaluate the altitude profile of the particle size exhibiting levitation. The inclusion of solar wind flux into analysis is noticed to reduce the sheath span and altitude of the particle levitation; the dependence of the sheath structure and particle levitation on the solar wind plasma parameters has been discussed and graphically presented.

Dysphagia associated with cervical spine and postural disorders.

Science.gov (United States)

Papadopoulou, Soultana; Exarchakos, Georgios; Beris, Alexander; Ploumis, Avraam

2013-12-01

Difficulties with swallowing may be both persistent and life threatening for the majority of those who experience it irrespective of age, gender, and race. The purpose of this review is to define oropharyngeal dysphagia and describe its relationship to cervical spine disorders and postural disturbances due to either congenital or acquired disorders. The etiology and diagnosis of dysphagia are analyzed, focusing on cervical spine pathology associated with dysphagia as severe cervical spine disorders and postural disturbances largely have been held accountable for deglutition disorders. Scoliosis, kyphosis–lordosis, and osteophytes are the primary focus of this review in an attempt to elucidate the link between cervical spine disorders and dysphagia. It is important for physicians to be knowledgeable about what triggers oropharyngeal dysphagia in cases of cervical spine and postural disorders. Moreover, the optimum treatment for dysphagia, including the use of therapeutic maneuvers during deglutition, neck exercises, and surgical treatment, is discussed.

The feasibility of transradial laser atherectomy for chronic total occlusion using the 5 Fr sheath system.

Science.gov (United States)

Sherif, Khaled; Yaqub, Yasir; Suarez, Jose A

2016-05-01

We present a case of chronic total occlusion (CTO) approached with LASER endovascular intervention by radial artery approach using a 5 French sheath. A 57-year-old man presented to our hospital having had retrosternal chest pain for two days. Physical examination was normal at the time of presentation. The laboratory tests were within normal limits, including cardiac enzymes except the lipid panel which showed hypertriglyceridemia. The patient underwent a myocardial perfusion scintigraphy stress test that revealed inferior wall ischemia, with normal left ventricular ejection fraction. A 5-French vascular sheath was placed in the right radial artery. Selective coronary artery angiography was performed, which showed right coronary artery (RCA) CTO. A 5-French JR4 guide catheter successfully engaged the RCA and Laser angioplasty was performed across the CTO into the RCA. A marked improvement of flow was evident thereafter. To best of our knowledge this is the first case report showing the feasibility of laser atherectomy using the 5 French sheath system in a coronary arterial CTO. Copyright © 2016 by Academy of Sciences and Arts of Bosnia and Herzegovina.

The Tubular Sheaths Encasing Methanosaeta thermophila Filaments Are Functional Amyloids.

Science.gov (United States)

Dueholm, Morten S; Larsen, Poul; Finster, Kai; Stenvang, Marcel R; Christiansen, Gunna; Vad, Brian S; Bøggild, Andreas; Otzen, Daniel E; Nielsen, Per Halkjær

2015-08-14

Archaea are renowned for their ability to thrive in extreme environments, although they can be found in virtually all habitats. Their adaptive success is linked to their unique cell envelopes that are extremely resistant to chemical and thermal denaturation and that resist proteolysis by common proteases. Here we employ amyloid-specific conformation antibodies and biophysical techniques to show that the extracellular cell wall sheaths encasing the methanogenic archaea Methanosaeta thermophila PT are functional amyloids. Depolymerization of sheaths and subsequent MS/MS analyses revealed that the sheaths are composed of a single major sheath protein (MspA). The amyloidogenic nature of MspA was confirmed by in vitro amyloid formation of recombinant MspA under a wide range of environmental conditions. This is the first report of a functional amyloid from the archaeal domain of life. The amyloid nature explains the extreme resistance of the sheath, the elastic properties that allow diffusible substrates to penetrate through expandable hoop boundaries, and how the sheaths are able to split and elongate outside the cell. The archaeal sheath amyloids do not share homology with any of the currently known functional amyloids and clearly represent a new function of the amyloid protein fold. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Malignant Peripheral Nerve Sheath Tumour of the Maxilla

Directory of Open Access Journals (Sweden)

Puja Sahai

2014-01-01

Full Text Available A 38-year-old man was diagnosed with malignant peripheral nerve sheath tumour of the maxilla. He was treated with total maxillectomy. Histopathological examination of the resected specimen revealed a close resection margin. The tumour was of high grade with an MIB-1 labelling index of almost 60%. At six weeks following the surgery, he developed local tumour relapse. The patient succumbed to the disease at five months from the time of diagnosis. The present report underlines the locally aggressive nature of malignant peripheral nerve sheath tumour of the maxilla which necessitates an early therapeutic intervention. A complete resection with clear margins is the most important prognostic factor for malignant peripheral nerve sheath tumour in the head and neck region. Adjuvant radiotherapy may be considered to improve the local control. Future research may demarcate the role of targeted therapy for patients with malignant peripheral nerve sheath tumour.

A CASE OF OSTEOPOROSIS OF THE SPINE IN AN ELDERLY MALE WITH CALCIFIC AORTIC STENOSIS

Directory of Open Access Journals (Sweden)

N. Yu. Karpova

2014-07-01

Full Text Available The given clinical example presents a case of concomitant diseases of the heart and axial skeleton. Calcific aortic stenosis detected by chance in an elderly male was associated with osteoporosis of the lumbar spine with moderate perturbation of the calcium–vitamin D–parathyroid hormone axis and with no classical risk factors for impaired bone mineral density. Possible approaches to pathogenetic therapy are described.

A CASE OF OSTEOPOROSIS OF THE SPINE IN AN ELDERLY MALE WITH CALCIFIC AORTIC STENOSIS

Directory of Open Access Journals (Sweden)

N. Yu. Karpova

2013-01-01

Full Text Available The given clinical example presents a case of concomitant diseases of the heart and axial skeleton. Calcific aortic stenosis detected by chance in an elderly male was associated with osteoporosis of the lumbar spine with moderate perturbation of the calcium–vitamin D–parathyroid hormone axis and with no classical risk factors for impaired bone mineral density. Possible approaches to pathogenetic therapy are described.

Applicability of the Child-Langmuir laws versions for describing the glow discharge cathode sheath in CO2

Science.gov (United States)

Lisovskiy, Valeriy; Krol, Hennadii; Osmayev, Ruslan; Yegorenkov, Vladimir

2016-09-01

This work is devoted to the determination of the law that may be applicable to the description of the cathode sheath in CO2. To this end three versions of the Child-Langmuir law have been considered - a collision free one (for the ions moving through a cathode sheath without collisions with gas molecules) as well as two collision- related versions- one for a constant mean free path of positive ions and one for a constant mobility of positive ions. The current-voltage characteristics and the cathode sheath thickness of the glow discharge in carbon oxide have been simultaneously measured in the pressure range from 0.05 to 1 Torr and with the discharge current values up to 80 mA. The inter-electrode distance has been chosen such that the discharge consists only of the cathode sheath and a small portion of the negative glow, i.e. the experiments have been performed in short tubes. In this case the voltage drop across the cathode sheath is equal approximately to the voltage drop across the electrodes. In the whole range of the discharge conditions we have studied the cathode sheath characteristics are found to obey correctly only to the Child-Langmuir law version with a constant ion mobility. The reason for this phenomenon may be related with a significant conversion of carbon dioxide molecules.

Collaborative Research: Understanding Ion Losses to Plasma Boundaries Sheaths and Presheaths

Energy Technology Data Exchange (ETDEWEB)

Hershkowitz, Noah [Univ. of Wisconsin, Madison, WI (United States)

2015-10-01

Sheaths are common to all bounded steady-state plasmas. This includes laboratory, industrial, fusion, and in some cases even space plasmas. They form in general to balance particle loss and maintain quasi-neutrality in plasmas. Electrons are lighter than the ions by 2000 times or more (depending on the gas), and in most plasmas ion temperatures are rarely higher than the electron temperature and generally much lower. Thus in most cases, negative potential sheaths occur to confine electrons and allow ions to be freely lost. We have investigated how a plasma locally response to a positive bias on a small electrode, and have established area criteria which plasma reacts differently to the positive bias – first a pure electron sheath, and a global non-ambipolar regime where all electrons are lost to the electrode, and a double layer structure identified as a virtual cathode forms to limiting electron loss and maintain quasi-neutrality, and finally a anode spot regime where a secondary discharge occurs in front of the electrode, turning it into the major loss area of the entire plasma. Electrode area and plasma parameters criteria for these regimes were established, and the effect of the virtual cathode on the electrode’s I-V characteristics was investigated. We have also developed a global non-ambipolar electron source to replace hollow cathodes in a number of plasma applications. This eliminates the lifetime limitation and maintenance cost of hollow cathodes as they easily wear out easily and cannot be replaced in space applications.

Cervical spine injury in the elderly: imaging features

Energy Technology Data Exchange (ETDEWEB)

Ehara, S. [Dept. of Radiology, Iwate Medical University School of Medicine, Morioka (Japan); Shimamura, Tadashi [Dept. of Orthopedic Surgery, Iwate Medical University School of Medicine, Morioka (Japan)

2001-01-01

An increase in the elderly population has resulted in an increased incidence of cervical spine injury in this group. No specific type of cervical spine trauma is seen in the elderly, although dens fractures are reported to be common. Hyperextension injuries due to falling and the resultant central cord syndrome in the mid and lower cervical segments due to decreased elasticity as a result of spondylosis may be also characteristic. The imaging features of cervical spine injury are often modified by associated spondylosis deformans, DISH and other systemic disorders. The value of MR imaging in such cases is emphasized. (orig.)

Frontal plane fractures of the accessory carpal bone and implications for the carpal sheath of the digital flexor tendons.

Science.gov (United States)

Minshall, G J; Wright, I M

2014-09-01

Accurate radiological and ultrasonographic descriptions of frontal plane fractures of the accessory carpal bone (ACB) are lacking, and implications of these fractures for the carpal sheath and its contents have not previously been reported. Aims were as follows: 1) to describe the location and radiological features of frontal plane fractures of the ACB; 2) to document communication of displaced fractures with the carpal sheath and consequent injury to the deep digital flexor tendon (DDFT); 3) to describe ultrasonographic identification of lesions; and 4) to report tenoscopic evaluation and treatment. Retrospective case series. Analysis of frontal plane fractures of the ACB referred to a single hospital between 2006 and 2012, including review of radiographic, ultrasonographic and tenoscopic images. Nine fractures were identified, of which 8 displaced fractures all communicated with the carpal sheath. Comminuted fragments and/or protruding fracture margins lacerated the lateral margin of the enclosed DDFT. This was identifiable ultrasonographically and confirmed at tenoscopy in 7 cases. Treatment in these horses consisted of removal of torn tendon tissue together with fragmentation and protuberant fracture edges, and 7 of 7 cases returned to work. One horse with a nondisplaced fracture was managed with immobilisation; the fracture healed, and the horse returned to work. One horse with a displaced fracture was retired to stud. Frontal plane fractures of the ACB occur palmar to the groove in its lateral margin for the tendon of insertion of ulnaris lateralis. Comminuted fragments can displace distally within the carpal sheath to a mid-metacarpal level or abaxially to lie extrathecally, lateral to the parent bone. Displaced fractures communicate with the carpal sheath and traumatise the DDFT. © 2013 EVJ Ltd.

Zircaloy sheathed thermocouples for PWR fuel rod temperature measurements

International Nuclear Information System (INIS)

Anderson, J.V.; Wesley, R.D.; Wilkins, S.C.

1979-01-01

Small diameter zircaloy sheathed thermocouples have been developed by EG and G Idaho, Inc., at the Idaho National Engineering Laboratory. Surface mounted thermocouples were developed to measure the temperature of zircaloy clad fuel rods used in the Thermal Fuels Behavior Program (TFBP), and embedded thermocouples were developed for use by the Loss-of-Fluid Test (LOFT) Program for support tests using zircaloy clad electrically heated nuclear fuel rod simulators. The first objective of this developmental effort was to produce zircaloy sheathed thermocouples to replace titanium sheathed thermocouples and thereby eliminate the long-term corrosion of the titanium-to-zircaloy attachment weld. The second objective was to reduce the sheath diameter to obtain faster thermal response and minimize cladding temperature disturbance due to thermocouple attachment

Morphometric Analysis of Connective Tissue Sheaths of Sural Nerve in Diabetic and Nondiabetic Patients

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Braca Kundalić

2014-01-01

Full Text Available One of the most common complications of diabetes mellitus is diabetic neuropathy. It may be provoked by metabolic and/or vascular factors, and depending on duration of disease, various layers of nerve may be affected. Our aim was to investigate influence of diabetes on the epineurial, perineurial, and endoneurial connective tissue sheaths. The study included 15 samples of sural nerve divided into three groups: diabetic group, peripheral vascular disease group, and control group. After morphological analysis, morphometric parameters were determined for each case using ImageJ software. Compared to the control group, the diabetic cases had significantly higher perineurial index (P<0.05 and endoneurial connective tissue percentage (P<0.01. The diabetic group showed significantly higher epineurial area (P<0.01, as well as percentage of endoneurial connective tissue (P<0.01, in relation to the peripheral vascular disease group. It is obvious that hyperglycemia and ischemia present in diabetes lead to substantial changes in connective tissue sheaths of nerve, particularly in peri- and endoneurium. Perineurial thickening and significant endoneurial fibrosis may impair the balance of endoneurial homeostasis and regenerative ability of the nerve fibers. Future investigations should focus on studying the components of extracellular matrix of connective tissue sheaths in diabetic nerves.

Analytical solutions and particle simulations of cross-field plasma sheaths

International Nuclear Information System (INIS)

Gerver, M.J.; Parker, S.E.; Theilhaber, K.

1989-01-01

Particles simulations have been made of an infinite plasma slab, bounded by absorbing conducting walls, with a magnetic field parallel to the walls. The simulations have been either 1-D, or 2-D, with the magnetic field normal to the simulation plane. Initially, the plasma has a uniform density between the walls, and there is a uniform source of ions and electrons to replace particles lost to the walls. In the 1-D case, there is no diffusion of the particle guiding centers, and the plasma remains uniform in density and potential over most of the slab, with sheaths about a Debye length wide where the potential rises to the wall potential. In the 2-D case, the density profile becomes parabolic, going almost to zero at the walls, and there is a quasineutral presheath in the bulk of the plasma, in addition to sheaths near the walls. Analytic expressions are found for the density and potential profiles in both cases, including, in the 2-D case, the magnetic presheath due to finite ion Larmor radius, and the effects of the guiding center diffusion rate being either much less than or much grater than the energy diffusion rate. These analytic expressions are shown to agree with the simulations. A 1-D simulation with Monte Carlo guiding center diffusion included gives results that are good agreement with the much more expensive 2-D simulation. 17 refs., 10 figs

Physics of the intermediate layer between a plasma and a collisionless sheath and mathematical meaning of the Bohm criterion

Energy Technology Data Exchange (ETDEWEB)

Almeida, N. A.; Benilov, M. S. [Departamento de Fisica, CCCEE, Universidade da Madeira Largo do Municipio, 9000 Funchal (Portugal)

2012-07-15

A transformation of the ion momentum equation simplifies a mathematical description of the transition layer between a quasi-neutral plasma and a collisionless sheath and clearly reveals the physics involved. Balance of forces acting on the ion fluid is delicate in the vicinity of the sonic point and weak effects come into play. For this reason, the passage of the ion fluid through the sonic point, which occurs in the transition layer, is governed not only by inertia and electrostatic force but also by space charge and ion-atom collisions and/or ionization. Occurrence of different scenarios of asymptotic matching in the plasma-sheath transition is analyzed by means of simple mathematical examples, asymptotic estimates, and numerical calculations. In the case of a collisionless sheath, the ion speed distribution plotted on the logarithmic scale reveals a plateau in the intermediate region between the sheath and the presheath. The value corresponding to this plateau has the meaning of speed with which ions leave the presheath and enter the sheath; the Bohm speed. The plateau is pronounced reasonably well provided that the ratio of the Debye length to the ion mean free path is of the order of 10{sup -3} or smaller. There is no such plateau if the sheath is collisional and hence no sense in talking of a speed with which ions enter the sheath.

Survey of French spine surgeons reveals significant variability in spine trauma practices in 2013.

Science.gov (United States)

Lonjon, G; Grelat, M; Dhenin, A; Dauzac, C; Lonjon, N; Kepler, C K; Vaccaro, A R

2015-02-01

In France, attempts to define common ground during spine surgery meetings have revealed significant variability in clinical practices across different schools of surgery and the two specialities involved in spine surgery, namely, neurosurgery and orthopaedic surgery. To objectively characterise this variability by performing a survey based on a fictitious spine trauma case. Our working hypothesis was that significant variability existed in trauma practices and that this variability was related to a lack of strong scientific evidence in spine trauma care. We performed a cross-sectional survey based on a clinical vignette describing a 31-year-old male with an L1 burst fracture and neurologic symptoms (numbness). Surgeons received the vignette and a 14-item questionnaire on the management of this patient. For each question, surgeons had to choose among five possible answers. Differences in answers across surgeons were assessed using the Index of Qualitative Variability (IQV), in which 0 indicates no variability and 1 maximal variability. Surgeons also received a questionnaire about their demographics and surgical experience. Of 405 invited spine surgeons, 200 responded to the survey. Five questions had an IQV greater than 0.9, seven an IQV between 0.5 and 0.9, and two an IQV lower than 0.5. Variability was greatest about the need for MRI (IQV=0.93), degree of urgency (IQV=0.93), need for fusion (IQV=0.92), need for post-operative bracing (IQV=0.91), and routine removal of instrumentation (IQV=0.94). Variability was lowest for questions about the need for surgery (IQV=0.42) and use of the posterior approach (IQV=0.36). Answers were influenced by surgeon specialty, age, experience level, and type of centre. Clinical practice regarding spine trauma varies widely in France. Little published evidence is available on which to base recommendations that would diminish this variability. Copyright © 2015. Published by Elsevier Masson SAS.

The spine problem: Finding a function for dendritic spines

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Sarah eMalanowski

2014-09-01

Full Text Available Why do neurons have dendritic spines? This question— the heart of what Yuste calls the spine problem— presupposes that why-questions of this sort have scientific answers: that empirical findings can favor or count against claims about why neurons have spines. Here we show how such questions can receive empirical answers. We construe such why-questions as questions about how spines make a difference to the behavior of some mechanism that we take to be significant. Why-questions are driven fundamentally by the effort to understand how some item, such as the dendritic spine, is situated in the causal structure of the world (the causal nexus. They ask for a filter on that busy world that allows us to see a part’s individual contribution to a mechanism, independent of everything else going on. So understood, answers to why-questions can be assessed by testing the claims these answers make about the causal structure of a mechanism. We distinguish four ways of making a difference to a mechanism (necessary, modulatory, component, background condition, and we sketch their evidential requirements. One consequence of our analysis is that there are many spine problems and that any given spine problem might have many acceptable answers.

Three-dimensional MR myelography of the lumbar spine: comparative case study to X-ray myelography

International Nuclear Information System (INIS)

Eberhardt, K.E.W.; Hollenbach, H.P.; Tomandl, B.; Huk, W.J.

1997-01-01

Conventional myelography was compared with a new type of MR technique using a fat-suppressing 3D fast imaging with steady precession (FISP) sequence for diagnosis of the lumbar root compression syndrome. 80 patients with discogenic disease in the lumbar spine were examined with a 1.0-T whole-body MR system (Siemens Magnetom Impact, Erlangen, Germany). A strongly T2 * -weighted 3D FISP sequence was applied in the sagittal orientation. To obtain fat suppression, a frequency-selective 1-3-3-1 prepulse was applied prior to the imaging sequence. The acquired 3D data set was evaluated using a maximum intensity projection (MIP) program. The measurement time was 7 min, 47 s. Magnetic resonance myelography has significant advantages over conventional myelography, particularly in cases of extreme spinal canal stenosis. Compared with the conventional method, this new MR technique shows comparable sensitivity in the visualization of the spinal nerve roots in the lumbar spine. (orig.). With 5 figs., 2 tabs

Is the cervical spine clear? Undetected cervical fractures diagnosed only at autopsy.

Science.gov (United States)

Sweeney, J F; Rosemurgy, A S; Gill, S; Albrink, M H

1992-10-01

Undetected cervical-spine injuries are a nemesis to both trauma surgeons and emergency physicians. Radiographic protocols have been developed to avoid missing cervical-spine fractures but are not fail-safe. Three case reports of occult cervical fractures documented at autopsy in the face of normal cervical-spine radiographs and computerized tomography scans are presented.

Rare cause of neck pain: tumours of the posterior elements of the cervical spine.

Science.gov (United States)

Katsuura, Yoshihiro; Cason, Garrick; Osborn, James

2016-12-15

Here we present two cases of primary bone tumours of the cervical spine in patients who had persistent neck pain-in one case, lasting 8 years. In each case, there was a delay in diagnosis and referral to a spine specialist was prolonged. Primary bone tumours of the spine are rare, which is in contrast to the wide prevalence of cervical neck pain. Many primary care providers may go an entire career without encountering a symptomatic primary cervical spine tumour. In this paper, we discuss the clinical course and treatment of each patient and review the current literature on primary bone tumours of the spine. Owing to the subtle roentgenographic findings of primary cervical tumours, we highlight the importance of advanced imaging in the clinical work-up of simple axial neck pain lasting >6 weeks to avoid misdiagnosis of serious pathology. 2016 BMJ Publishing Group Ltd.

Importance of lateral spine view in DEXA bone densitometry

International Nuclear Information System (INIS)

Hussain, R.; Khan, A.S.M.H.; Momtaz, S.; Rahman, M.U.; Jehan, A.H.

2002-01-01

Aim: Bone Mineral Density (BMD) measurement is an invaluable technique for assessing fracture risk in suspected cases of osteoporosis. The routine procedure includes AP spine and hip views. But quite often there are discordant results between them, bone mineral concentration (BMC) in the AP spine appears higher than hip. Our study was done to establish the importance of lateral spine view. The lateral view would provide better scope to draw the ROI perfectly and so BMC would be more accurately measured. Materials and Methods: In a prospective study a total of 60 consecutive patients (48F, 12M) were evaluated for bone densitometric measurements. The age group was 35 - 80 years (Mean 59 years). None of the patients received estrogen, biphosphonates or steroid therapy. Bone density of the hip and lumbar spine were measured with Norland XR 36. The T-score, which measures the difference between patient's BMD and young-normal was computed and age-matched Z-score were calculated. X-ray correlation was also done in most of the cases. Results: When we analyzed the femoral neck values, 30 cases were osteoporotic and 23 were osteopenic whereas according to AP spine views only 20 were osteoporotic and 30 were osteopenic. So, clearly a significant number of patients having osteoporosis were interpreted as osteopenia (P 0.05). But in the same vertebra there were significant differences (P<0.05) of BMC measured with AP and lateral views. Conclusion: The lateral view can exclude the posterior element of the vertebra as well as the aorta anteriorly, where a high incidence of calcified atherosclerotic plaques are present. AP view includes these drawbacks resulting in falsely higher BMC. Lateral spine view can eliminate these problems and so it provides an important role in BMD measurements. The authors recommend that it should be included in routine practice

Black-hole creation in quantum cosmology

Energy Technology Data Exchange (ETDEWEB)

Zhong Chao, Wu [Rome, Univ. `La Sapienza` (Italy). International Center for Relativistic Astrophysics]|[Specola Vaticana, Vatican City State (Vatican City State, Holy See)

1997-11-01

It is proven that the probability of a black hole created from the de Sitter space-time background, at the Wkb level, is the exponential of one quarter of the sum of the black hole and cosmological horizon areas, or the total entropy of the universe. This is true not only for the spherically symmetric cases of the Schwarzschild or Reissner-Nordstroem black holes, but also for the rotating cases of the Kerr black hole and the rotating charged case of the Newman black hole. The de Sitter metric is the most probable evolution at the Planckian era of the universe.

Significance of rice sheath photosynthesis: Yield determination by ...

African Journals Online (AJOL)

Using high-yielding hybrid rice Liangyopeijiu (LYP9), its male parent 9311 and hybrid rice Shanyou 63 (SY63) as the experimental materials, the photosynthesis of rice sheath was studied by 14C radio-autography. The results showed that rice sheath could trap sunlight and produce photosynthates, and these ...

Spontaneous traumatic macular hole closure in a 50-year-old woman: a case report

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Rotsos Tryfon

2011-07-01

Full Text Available Abstract Introduction Traumatic macular holes (TMH are well-known complications of ocular contusion injury. Spontaneous closure occurs in approximately 50% of cases, but rarely after the age of thirty. We report a case of spontaneous closure of a full thickness macular hole due to a blunt trauma and we suggest possible mechanisms for this closure. Case presentation A 50-year-old Greek woman was referred with a history of reduced best-corrected visual acuity after blunt trauma to her right eye. Diagnosis was based on fundoscopic, optical coherence tomography as well as fluorescein angiography findings with follow-up visits at two days, 20 days and five months. Fundoscopy revealed a full-thickness TMH with a minor sub-retinal hemorrhage and posterior vitreous detachment. The presence of a coagulum in the TMH base was observed. Subsequently, TMH closure was observed. Conclusion The clot in the TMH base, potentially a hemorrhage by-product containing a significant quantity of platelets, may have simulated the clot observed after autologous serum use, thus facilitating a similar effect. This may have stimulated glial cell migration and proliferation, thus contributing to spontaneous hole closure.

Sheath-accumulating Propagation of Interplanetary Coronal Mass Ejection

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Takuya; Shibata, Kazunari, E-mail: takahasi@kusastro.kyoto-u.ac.jp [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607–8471 (Japan)

2017-03-10

Fast interplanetary coronal mass ejections (ICMEs) are the drivers of strong space weather storms such as solar energetic particle events and geomagnetic storms. The connection between the space-weather-impacting solar wind disturbances associated with fast ICMEs at Earth and the characteristics of causative energetic CMEs observed near the Sun is a key question in the study of space weather storms, as well as in the development of practical space weather prediction. Such shock-driving fast ICMEs usually expand at supersonic speeds during the propagation, resulting in the continuous accumulation of shocked sheath plasma ahead. In this paper, we propose a “sheath-accumulating propagation” (SAP) model that describes the coevolution of the interplanetary sheath and decelerating ICME ejecta by taking into account the process of upstream solar wind plasma accumulation within the sheath region. Based on the SAP model, we discuss (1) ICME deceleration characteristics; (2) the fundamental condition for fast ICMEs at Earth; (3) the thickness of interplanetary sheaths; (4) arrival time prediction; and (5) the super-intense geomagnetic storms associated with huge solar flares. We quantitatively show that not only the speed but also the mass of the CME are crucial for discussing the above five points. The similarities and differences between the SAP model, the drag-based model, and the“snow-plow” model proposed by Tappin are also discussed.

Sheath-accumulating Propagation of Interplanetary Coronal Mass Ejection

International Nuclear Information System (INIS)

Takahashi, Takuya; Shibata, Kazunari

2017-01-01

Fast interplanetary coronal mass ejections (ICMEs) are the drivers of strong space weather storms such as solar energetic particle events and geomagnetic storms. The connection between the space-weather-impacting solar wind disturbances associated with fast ICMEs at Earth and the characteristics of causative energetic CMEs observed near the Sun is a key question in the study of space weather storms, as well as in the development of practical space weather prediction. Such shock-driving fast ICMEs usually expand at supersonic speeds during the propagation, resulting in the continuous accumulation of shocked sheath plasma ahead. In this paper, we propose a “sheath-accumulating propagation” (SAP) model that describes the coevolution of the interplanetary sheath and decelerating ICME ejecta by taking into account the process of upstream solar wind plasma accumulation within the sheath region. Based on the SAP model, we discuss (1) ICME deceleration characteristics; (2) the fundamental condition for fast ICMEs at Earth; (3) the thickness of interplanetary sheaths; (4) arrival time prediction; and (5) the super-intense geomagnetic storms associated with huge solar flares. We quantitatively show that not only the speed but also the mass of the CME are crucial for discussing the above five points. The similarities and differences between the SAP model, the drag-based model, and the“snow-plow” model proposed by Tappin are also discussed.

Experimental test of models of radio-frequency plasma sheaths

International Nuclear Information System (INIS)

Sobolewski, M.A.

1997-01-01

The ion current and sheath impedance were measured at the radio-frequency-powered electrode of an asymmetric, capacitively coupled plasma reactor, for discharges in argon at 1.33 endash 133 Pa. The measurements were used to test the models of the radio frequency sheath derived by Lieberman [IEEE Trans. Plasma Sci. 17, 338 (1989)] and Godyak and Sternberg [Phys. Rev. A 42, 2299 (1990)], and establish the range of pressure and sheath voltage in which they are valid. copyright 1997 American Institute of Physics

Pattern and presentation of spine trauma in Gwagwalada‑Abuja ...

African Journals Online (AJOL)

Results: There were 202 patients with male preponderance and a mean age of 38.9 ± 11.4 years over the 11‑year period. The most common cause of spine injury was road traffic injury (79.7%). Cervical spine injury (10.4%) accounted for the highest number of cases with complete neurologic deficit. The majority of patients, ...

Lumbar spine chordoma

Directory of Open Access Journals (Sweden)

M.A. Hatem, M.B.Ch.B, MRes, LMCC

2014-01-01

Full Text Available Chordoma is a rare tumor arising from notochord remnants in the spine. It is slow-growing, which makes it difficult to diagnose and difficult to follow up after treatment. Typically, it occurs in the base of the skull and sacrococcygeal spine; it rarely occurs in other parts of the spine. CT-guided biopsy of a suspicious mass enabled diagnosis of lumbar spine chordoma.

Studies on the transmission of sub-THz waves in magnetized inhomogeneous plasma sheath

Science.gov (United States)

Yuan, Kai; Shen, Linfang; Yao, Ming; Deng, Xiaohua; Chen, Zhou; Hong, Lujun

2018-01-01

There have been many studies on the sub-terahertz (sub-THz) wave transmission in reentry plasma sheaths. However, only some of them have paid attention to the transmission of sub-THz waves in magnetized plasma sheaths. In this paper, the transmission of sub-THz waves in both unmagnetized and magnetized reentry plasma sheaths was investigated. The impacts of temporal evolution of the plasma sheath on the wave transmission were studied. The transmission of "atmospheric window" frequencies in a magnetized plasma sheath was discussed in detail. According to the study, the power transmission rates (Tp) for the left hand circular (LHC) and the right hand circular modes in the magnetized plasma sheath are obviously higher and lower than those in the unmagnetized plasma sheath, respectively. The Tp of LHC mode increases with both wave frequency and external magnetic field strength. Also, the Tp of LHC mode in both magnetized and unmagnetized plasma sheaths varies with time due to the temporal evolution of the plasma sheath. Moreover, the performance of sub-THz waves in magnetized plasma sheath hints at a new approach to the "blackout" problem. The new approach, which is in the capability of modern technology, is to utilize the communication system operating at 140 GHz with an onboard magnet installed near the antenna.

The dust motion inside the magnetized sheath - The effect of drag forces

International Nuclear Information System (INIS)

Pandey, B. P.; Samarian, A.; Vladimirov, S. V.

2010-01-01

The isolated charged dust inside the magnetized plasma sheath moves under the influence of the electron and ion drag force and the sheath electrostatic field. The charge on the dust is a function of its radius as well as the value of the ambient sheath potential. It is shown that the charge on the dust determines its trajectory and dust performs the spiraling motion inside the sheath. The location of the turning spiral is determined by the number of negative charge on the dust, which in turn is a function of the dust radius. The back and forth spiraling motion finally causes the dust to move in a small, narrow region of the sheath. For a bigger dust particle, the dust moves closer to the sheath presheath boundary suggesting that the bigger grains, owing to the strong repulsion between the wall and dust, will be unable to travel inside the sheath. Only small, micron-sized grains can travel closer to the wall before repulsion pushes it back toward the plasma-sheath boundary. The temporal behavior of the spiraling dust motion appears like a damped harmonic oscillation, suggesting that the plasma drag force causes dissipation of the electrostatic energy. However, after initial damping, the grain keeps oscillating although with much smaller amplitude. The possible application of the present results to the ongoing sheath experiments is discussed.

Fatal Cervical Spine Injury Following a Bicycle Crash

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Uhrenholt Lars

2017-06-01

Full Text Available Spinal injury following direct loading of the head and neck is a rare sequel of bicycle crashes. Fatal head injuries following bicycle crashes have been described in great detail and safety measures such as bicycle helmets have been developed accordingly. Less frequently, however, potentially severe cervical spine injuries have been described. We present the case of a middle-aged female who sustained an ultimately fatal cervical spine injury following a collision with a car whilst biking wearing a helmet. We discuss the literature regarding the protective effects of bicycle helmets, the relevance to cervical spine injury and legislation on mandatory use of helmets for injury prevention.

Fabrication and use of zircaloy/tantalum-sheathed cladding thermocouples and molybdenum/rhenium-sheathed fuel centerline thermocouples

International Nuclear Information System (INIS)

Wilkins, S.C.; Sepold, L.K.

1985-01-01

The thermocouples described in this report are zircaloy/tantalum-sheathed and molybdenum/rhenium alloy-sheathed instruments intended for fuel rod cladding and fuel centerline temperature measurements, respectively. Both types incorporate beryllium oxide insulation and tungsten/rhenium alloy thermoelements. These thermocouples, operated at temperatures of 2000 0 C and above, were developed for use in the internationally sponsored Severe Fuel Damage test series in the Power Burst Facility. The fabrication steps for both thermocouple types are described in detail. A laser-welding attachment technique for the cladding-type thermocouple is presented, and experience with alternate materials for cladding and fuel therocouples is discussed

Recurring intracranial malignant peripheral nerve sheath tumor: case report and systematic review of the literature

NARCIS (Netherlands)

van den Munckhof, Pepijn; Germans, Menno R.; Schouten-van Meeteren, Antoinette Y. N.; Oldenburger, Foppe; Troost, Dirk; Vandertop, W. Peter

2011-01-01

To report the clinical presentation and management of an intracranial frontoparietal malignant peripheral nerve sheath tumor (MPNST) and its recurrence in a 6-year-old girl, along with a systematic review of the literature. A previously healthy 6-year-old girl presented with severe signs of

Reexcision Perineural Invasion and Epithelial Sheath Neuroma Possibly on a Spectrum of Postinjury Reactive Hyperplasia Mediated by IL-6.

Science.gov (United States)

Wang, James Y; Nuovo, Gerard; Kline, Mitchell; Magro, Cynthia M

2017-01-01

Epithelial sheath neuroma is a rarely recognized but established entity in the medical literature. First described in 2000 by Requena et al, there have only been 7 published cases to date, mostly in female patients and presenting as symptomatic solitary lesions on the back without a known history of trauma. In 2006, Beer et al described and reviewed a dozen cases in which epithelial sheath neuroma-like features were seen in the advent of a surgical procedure, which was termed "re-excision perineural invasion" and attributed to possible eccrine duct implantation during surgery. Our case is a 66-year-old male patient who underwent an excision of a melanocytic neoplasm in which a reactive epithelial sheath neuroma was incidentally discovered in the excision specimen, adjacent to the biopsy site cicatrix. Histologically, there was benign cutaneous nerve hyperplasia with a proliferation of squamous epithelium in intimate apposition to the nerve bundles in the superficial dermis. We postulate that the process active in the formation of re-excision perineural invasion is the same as in epithelial sheath neuroma and that minor trauma not appreciable on histologic examination is responsible in the latter entity. We performed IL-6 staining and documented that IL-6 was upregulated at the interface of the nerve and reactive epithelium, but was absent in nerves distant from the site of surgery, suggesting that IL-6 may be essential to the lesion's development. The recognition of reactive epithelial sheath neuroma including the subcategory of re-excision perineural invasion is crucial for the dermatopathologist to prevent mislabeling this reactive entity as a perineural squamous cell carcinoma, which has clinical consequences for the patient such as wider re-excision and radiation treatment. Additionally, we have identified a potential pathophysiologic basis for this lesion.

An investigation of tendon sheathing filler migration into concrete

International Nuclear Information System (INIS)

Naus, D.J.; Oland, C.B.

1998-03-01

During some of the inspections at nuclear power plants with prestressed concrete containments, it was observed that the containments has experienced leakage of the tendon sheathing filler (i.e., streaks). The objective of this activity was to provide an indication of the extent of tendon sheathing filler leakage into the concrete and its affects on concrete properties. Literature was reviewed and concrete core samples were obtained from the Trojan Nuclear Plant and tested. The literature primarily addressed effects of crude or lubricating oils that are known to cause concrete damage. However, these materials have significantly different characteristics relative to the materials used as tendon sheathing fillers. Examination and testing of the concrete cores indicated that the appearance of tendon sheathing filler on the concrete surface was due to leakage from the conduits and its subsequent migration through cracks that were present. Migration of the tendon sheathing filler was confined to the cracks and there was no perceptible movement into the concrete. Results of compressive strength testing indicated that the concrete quality was consistent in the containment and that the strength had increased over 40% in 25.4 years relative to the average compressive strength at 28-days age

Spatial and Working Memory Is Linked to Spine Density and Mushroom Spines.

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Rasha Refaat Mahmmoud

Full Text Available Changes in synaptic structure and efficacy including dendritic spine number and morphology have been shown to underlie neuronal activity and size. Moreover, the shapes of individual dendritic spines were proposed to correlate with their capacity for structural change. Spine numbers and morphology were reported to parallel memory formation in the rat using a water maze but, so far, there is no information on spine counts or shape in the radial arm maze (RAM, a frequently used paradigm for the evaluation of complex memory formation in the rodent.24 male Sprague-Dawley rats were divided into three groups, 8 were trained, 8 remained untrained in the RAM and 8 rats served as cage controls. Dendritic spine numbers and individual spine forms were counted in CA1, CA3 areas and dentate gyrus of hippocampus using a DIL dye method with subsequent quantification by the Neuronstudio software and the image J program.Working memory errors (WME and latency in the RAM were decreased along the training period indicating that animals performed the task. Total spine density was significantly increased following training in the RAM as compared to untrained rats and cage controls. The number of mushroom spines was significantly increased in the trained as compared to untrained and cage controls. Negative significant correlations between spine density and WME were observed in CA1 basal dendrites and in CA3 apical and basal dendrites. In addition, there was a significant negative correlation between spine density and latency in CA3 basal dendrites.The study shows that spine numbers are significantly increased in the trained group, an observation that may suggest the use of this method representing a morphological parameter for memory formation studies in the RAM. Herein, correlations between WME and latency in the RAM and spine density revealed a link between spine numbers and performance in the RAM.

Spatial and Working Memory Is Linked to Spine Density and Mushroom Spines.

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Mahmmoud, Rasha Refaat; Sase, Sunetra; Aher, Yogesh D; Sase, Ajinkya; Gröger, Marion; Mokhtar, Maher; Höger, Harald; Lubec, Gert

2015-01-01

Changes in synaptic structure and efficacy including dendritic spine number and morphology have been shown to underlie neuronal activity and size. Moreover, the shapes of individual dendritic spines were proposed to correlate with their capacity for structural change. Spine numbers and morphology were reported to parallel memory formation in the rat using a water maze but, so far, there is no information on spine counts or shape in the radial arm maze (RAM), a frequently used paradigm for the evaluation of complex memory formation in the rodent. 24 male Sprague-Dawley rats were divided into three groups, 8 were trained, 8 remained untrained in the RAM and 8 rats served as cage controls. Dendritic spine numbers and individual spine forms were counted in CA1, CA3 areas and dentate gyrus of hippocampus using a DIL dye method with subsequent quantification by the Neuronstudio software and the image J program. Working memory errors (WME) and latency in the RAM were decreased along the training period indicating that animals performed the task. Total spine density was significantly increased following training in the RAM as compared to untrained rats and cage controls. The number of mushroom spines was significantly increased in the trained as compared to untrained and cage controls. Negative significant correlations between spine density and WME were observed in CA1 basal dendrites and in CA3 apical and basal dendrites. In addition, there was a significant negative correlation between spine density and latency in CA3 basal dendrites. The study shows that spine numbers are significantly increased in the trained group, an observation that may suggest the use of this method representing a morphological parameter for memory formation studies in the RAM. Herein, correlations between WME and latency in the RAM and spine density revealed a link between spine numbers and performance in the RAM.

Structural Conservation of the Myoviridae Phage Tail Sheath Protein Fold

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Aksyuk, Anastasia A.; Kurochkina, Lidia P.; Fokine, Andrei; Forouhar, Farhad; Mesyanzhinov, Vadim V.; Tong, Liang; Rossmann, Michael G. (SOIBC); (Purdue); (Columbia)

2012-02-21

Bacteriophage phiKZ is a giant phage that infects Pseudomonas aeruginosa, a human pathogen. The phiKZ virion consists of a 1450 {angstrom} diameter icosahedral head and a 2000 {angstrom}-long contractile tail. The structure of the whole virus was previously reported, showing that its tail organization in the extended state is similar to the well-studied Myovirus bacteriophage T4 tail. The crystal structure of a tail sheath protein fragment of phiKZ was determined to 2.4 {angstrom} resolution. Furthermore, crystal structures of two prophage tail sheath proteins were determined to 1.9 and 3.3 {angstrom} resolution. Despite low sequence identity between these proteins, all of these structures have a similar fold. The crystal structure of the phiKZ tail sheath protein has been fitted into cryo-electron-microscopy reconstructions of the extended tail sheath and of a polysheath. The structural rearrangement of the phiKZ tail sheath contraction was found to be similar to that of phage T4.

ICME-driven sheath regions deplete the outer radiation belt electrons

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Hietala, H.; Kilpua, E. K.; Turner, D. L.

2013-12-01

It is an outstanding question in space weather and solar wind-magnetosphere interaction studies, why some storms result in an increase of the outer radiation belt electron fluxes, while others deplete them or produce no change. One approach to this problem is to look at differences in the storm drivers. Traditionally drivers have been classified to Stream Interaction Regions (SIRs) and Interplanetary Coronal Mass Ejections (ICMEs). However, an 'ICME event' is a complex structure: The core is a magnetic cloud (MC; a clear flux rope structure). If the mass ejection is fast enough, it can drive a shock in front of it. This leads to the formation of a sheath region between the interplanetary shock and the leading edge of the MC. While both the sheath and the MC feature elevated solar wind speed, their other properties are very different. For instance, the sheath region has typically a much higher dynamic pressure than the magnetic cloud. Moreover, the sheath region has a high power in magnetic field and dynamic pressure Ultra Low Frequency (ULF) range fluctuations, while the MC is characterised by an extremely smooth magnetic field. Magnetic clouds have been recognised as important drivers magnetospheric activity since they can comprise long periods of very large southward Interplanetary Magnetic Field (IMF). Nevertheless, previous studies have shown that sheath regions can also act as storm drivers. In this study, we analyse the effects of ICME-driven sheath regions on the relativistic electron fluxes observed by GOES satellites on the geostationary orbit. We perform a superposed epoch analysis of 31 sheath regions from solar cycle 23. Our results show that the sheaths cause an approximately one order of magnitude decrease in the 24h-averaged electron fluxes. Typically the fluxes also stay below the pre-event level for more than two days. Further analysis reveals that the decrease does not depend on, e.g., whether the sheath interval contains predominantly northward

Electric sheath and presheath in a collisionless, finite ion temperature plasma

International Nuclear Information System (INIS)

Emmert, G.A.; Wieland, R.M.; Mense, A.T.; Davidson, J.N.

1980-01-01

The plasma-sheath equation for a collisionless plasma with arbitrary ion temperature in plane geometry is formulated. Outside the sheath, this equation is approximated by the plasma equation, for which an analytic solution for the electrostatic potential is obtained. In addition, the ion distribution function, the wall potential, and the ion energy and particle flux into the sheath are explicitly calculated. The plasma-sheath equation is also solved numerically with no approximation of the Debye length. The numerical results compare well with the analytical results when the Debye length is small

Rare causes of scoliosis and spine deformity: experience and particular features

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Pliarchopoulou Fani M

2007-10-01

Full Text Available Abstract Background Spine deformity can be idiopathic (more than 80% of cases, neuromuscular, congenital or neurofibromatosis-related. However, there are many disorders that may also be involved. We present our experience treating patients with scoliosis or other spine deformities related to rare clinical entities. Methods A retrospective study of the records of a school-screening study in North-West Greece was performed, covering a 10-year period (1992–2002. The records were searched for patients with deformities related to rare disorders. These patients were reviewed as regards to characteristics of underlying disorder and spine deformity, treatment and results, complications, intraoperative and anaesthesiologic difficulties particular to each case. Results In 13 cases, the spine deformity presented in relation to rare disorders. The underlying disorder was rare neurological disease in 2 cases (Rett syndrome, progressive hemidystonia, muscular disorders (facioscapulohumeral muscular dystrophy, arthrogryposis in 2 patients, osteogenesis imperfecta in 2 cases, Marfan syndrome, osteopetrosis tarda, spondyloepiphyseal dysplasia congenita, cleidocranial dysplasia and Noonan syndrome in 1 case each. In 2 cases scoliosis was related to other congenital anomalies (phocomelia, blindness. Nine of these patients were surgically treated. Surgery was avoided in 3 patients. Conclusion This study illustrates the fact that different disorders are related with curves with different characteristics, different accompanying problems and possible complications. Investigation and understanding of the underlying pathology is an essential part of the clinical evaluation and preoperative work-up, as clinical experience at any specific center is limited.

Atomic Structure of Type VI Contractile Sheath from Pseudomonas aeruginosa.

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Salih, Osman; He, Shaoda; Planamente, Sara; Stach, Lasse; MacDonald, James T; Manoli, Eleni; Scheres, Sjors H W; Filloux, Alain; Freemont, Paul S

2018-02-06

Pseudomonas aeruginosa has three type VI secretion systems (T6SSs), H1-, H2-, and H3-T6SS, each belonging to a distinct group. The two T6SS components, TssB/VipA and TssC/VipB, assemble to form tubules that conserve structural/functional homology with tail sheaths of contractile bacteriophages and pyocins. Here, we used cryoelectron microscopy to solve the structure of the H1-T6SS P. aeruginosa TssB1C1 sheath at 3.3 Å resolution. Our structure allowed us to resolve some features of the T6SS sheath that were not resolved in the Vibrio cholerae VipAB and Francisella tularensis IglAB structures. Comparison with sheath structures from other contractile machines, including T4 phage and R-type pyocins, provides a better understanding of how these systems have conserved similar functions/mechanisms despite evolution. We used the P. aeruginosa R2 pyocin as a structural template to build an atomic model of the TssB1C1 sheath in its extended conformation, allowing us to propose a coiled-spring-like mechanism for T6SS sheath contraction. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Two cases of congenital defects within transverse processes of lumbar spine; Dwa przypadki wad wrodzonych wyrostkow poprzecznych ledzwiowego odcinka kregoslupa

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Malawski, S.; Sokolski, B. [Klinika Ortopedii, Centrum Medyczne Ksztalcenia Podyplomowego, Otwock (Poland)

1993-12-31

Two cases of congenital defects of transverse processes of lumbar spine causing lumbalgia are described. The first one was produced by direct contact of the elongated processes with subsequent pseudoarthrosis. Hypertrophied processes caused stenosis around intervertebral foramen and irritated posterior neural branch in the second case. Surgical resection of the hypertrophied transverse processes has brought the cure. (author). 4 refs, 6 figs.

Bilateral rectal sheath hematomas after low-molecular weight heparin treatment in uremia.

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Xu, Lu; Liu, Lei; Li, Xinjian

2017-11-01

Rectus sheath hematomas (RSHs) are uncommon. They are usually unilateral and rarely bilateral. In this paper, we report the first case of spontaneous bilateral RSHs in a uremic patient after the administration of the first dose of low-molecular weight heparin during hemodialysis. The most interesting aspect of this case is that the main symptom of RSH in our patient was urinary bladder irritation. We highlight the importance of the prompt diagnosis and management of this medical emergency.

Gene Expression Profiling of the Intact Dermal Sheath Cup of Human Hair Follicles.

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Niiyama, Shiro; Ishimatsu-Tsuji, Yumiko; Nakazawa, Yosuke; Yoshida, Yuzo; Soma, Tsutomu; Ideta, Ritsuro; Mukai, Hideki; Kishimoto, Jiro

2018-04-24

Cells that constitute the dermal papillae of hair follicles might be derived from the dermal sheath, the peribulbar component of which is the dermal sheath cup. The dermal sheath cup is thought to include the progenitor cells of the dermal papillae and possesses hair inductive potential; however, it has not yet been well characterized. This study investigated the gene expression profile of the intact dermal sheath cup, and identified dermal sheath cup signature genes, including extracellular matrix components and BMP-binding molecules, as well as TGF-b1 as an upstream regulator. Among these, GREM2, a member of the BMP antagonists, was found by in situ hybridization to be highly specific to the dermal sheath cup, implying that GREM2 is a key molecule contributing to maintenance of the properties of the dermal sheath cup.

Compression test of cold-formedsteel perforated profile with steel sheathing

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Shamanin Aleksandr Yur’evich

2015-05-01

Full Text Available The subject of this paper is the stability and strength of cold-formed and perforated steel sigma-section columns with steel sheathing of different thickness. Ceilings with and without steel sheathing of different thickness are tested to failure in compression on a laboratory machine, which was based on a manual hydraulic jack. Series of 4 experiments with full-scale walls (2.5 m height were carried out. Also, for examination of the role of boundary conditions, the sheet in a ceiling is either left free or connected to base with screws.In civil engineering there are many experiments and methodologies for calculating the strength and buckling of ceiling with the sheathing of various materials, such as oriented strand board and gypsum board. However, for producing superstructures of ships the materials with high plastic properties and strength characteristics are required. For example steel possesses such properties. It was the main reason for conducting a series of experiments and studying the behavior of cold-formed steel columns with steel sheathing. During the experiments the deformation of the cross-section of three equally spaced cross sections was determined, as well as the axial deformation of the central column in the ceiling with steel sheathing.The test results showed the influence of the thickness of sheathing and boundary condition of a sheet on the strength and buckling of ceiling. According to the results of the tests it is necessary to evaluate the impact of the sheathing made of different materials and if necessary to carry out further tests.

Decreased bed rest post-percutaneous coronary intervention with a 7-French arterial sheath and its effects on vascular complications.

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Wentworth, Laura J; Bechtum, Elizabeth L; Hoffman, Jessica G; Kramer, Robert R; Bartel, David C; Slusser, Joshua P; Tilbury, Ralph Thomas

2018-01-01

To compare the incidence of femoral access puncture site complications in the control group, who underwent 6 hr of bed rest, with patients in the case group, who underwent 4 hr of bed rest. The ideal bed rest length after percutaneous coronary intervention with a 7-French arterial sheath has been investigated by nursing practice. However, in this larger-sheath-size group, best practices have not been determined, and bed rest time continues to vary markedly among institutions. Retrospective study. Data were retrieved from the National Cardiovascular Data Registry and electronic health records in this retrospective study. Sample size was 401 patients: 152 case patients with 4-hr bed rest and 249 controls with 6-hr bed rest. Case group data were obtained from 20 May 2013-31 December 2014; and control group data, 15 June 2011-20 May 2013. National Cardiovascular Data Registry event rates were generally low in both groups: Only three patients in each group had a bleeding event within 72 hr (2% vs. 1%) and no patient and only two controls had arteriovenous fistula (0% vs. 1%). Complications documented in the electronic health records with institutional femoral access puncture site complication definitions identified bleeding at the access site in eight case patients (5%) and nine controls (4%). Haematoma at the access site occurred in 21 case patients (14%) and 25 controls (10%). The practice change of decreasing bed rest from 6-4 hr for patients with 7-French arterial sheaths post-percutaneous coronary intervention was associated with no significant change in femoral access puncture site complications in either National Cardiovascular Data Registry data or institutional electronic health records data. This introduces expanded evidence of safety in decreasing bed rest length in larger (7-French) arterial sheaths post-percutaneous coronary intervention. © 2017 John Wiley & Sons Ltd.

Experimental evaluation of the stability of goat's cervical spine after percutaneous cervical diskectomy

International Nuclear Information System (INIS)

Du Zhongli; Zhou Yicheng; Wang Chengyuan; Hong Cheng; Liu Hanqiao; Zhang Jiangfan; Ding Hui; Feng Dingyi

1999-01-01

Objective: To evaluate the stability of the goat's cervical spine after PCD (percutaneous cervical diskectomy). Methods: Ten adult goats were studied. Seven had PCD at C 3-4 , and three at C 4-5 . The cervical spine of the goat was studied with MR using axial, corona land sagittal images and with anteroposterior and lateral radiographs before and after PCD. The height of the disk, the disk space angle and dislocation were measured respectively before and after PCD. The data were examined by t-test. Results: The disk space (7 cases, 70%) became narrow obviously, and hyperostosis (5 cases, 50%) disk bulging (4 cases, 40%) appeared after PCD, but there was no obvious dislocation or angulation between the adjacent vertebral bodies. Conclusions: The stability of the goat's cervical spine is not affected after PCD. Indicating that this might also hold true for human cervical spine

Thermionic emission from monolayer graphene, sheath formation and its feasibility towards thermionic converters

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Misra, Shikha; Upadhyay Kahaly, M.; Mishra, S. K.

2017-02-01

A formalism describing the thermionic emission from a single layer graphene sheet operating at a finite temperature and the consequent formation of the thermionic sheath in its proximity has been established. The formulation takes account of two dimensional densities of state configuration, Fermi-Dirac (f-d) statistics of the electron energy distribution, Fowler's treatment of electron emission, and Poisson's equation. The thermionic current estimates based on the present analysis is found to be in reasonably good agreement with experimental observations (Zhu et al., Nano Res. 07, 1 (2014)). The analysis has further been simplified for the case where f-d statistics of an electron energy distribution converges to Maxwellian distribution. By using this formulation, the steady state sheath features, viz., spatial dependence of the surface potential and electron density structure in the thermionic sheath are derived and illustrated graphically for graphene parameters; the electron density in the sheath is seen to diminish within ˜10 s of Debye lengths. By utilizing the graphene based cathode in configuring a thermionic converter (TC), an appropriate operating regime in achieving the efficient energy conversion has been identified. A TC configured with the graphene based cathode (operating at ˜1200 K/work function 4.74 V) along with the metallic anode (operating at ˜400 K/ work function 2.0 V) is predicted to display ˜56% of the input thermal flux into the electrical energy, which infers approximately ˜84% of the Carnot efficiency.

A STUDY OF EPIDEMIOLOGY OF SPINE INJURY IN FALL FROM HEIGHT

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Amel Antony

2016-09-01

Full Text Available BACKGROUND This study puts in a sincere effort to study the spinal cord injuries in cases of fall from height. This study is intended to help the fellow radiologists to identify and thus help the individuals to cut down the progression of the disease. Identifying the spinal trauma and its clinic - epidemiological aspects will help further the practicing clinicians. The study can also help in formulation of preventive measures and putting forward management protocols in cases of spinal injury. METHODS This study was done in the Department of Radiology, Travancore Medical College, Kollam. This study was done from June 2104 to march 2016. Thirty two cases were identified and were taken up for the study. INCLUSION CRITERIA Spinal injuries following fall from height. EXCLUSION CRITERIA 1. Other spinal pathologies were not considered for the study. 2. Diabetic patients were excluded. RESULTS In the present study male sex amounted to ninety percent which amounted to twenty nine cases of spinal injury followed by female sex which amounted to ten percent which amounted to three cases. The age wise distribution of cases showed that age group of twenty to forty years showed maximum number of cases which amounted to sixteen admissions followed by age group of forty to sixty years which amounted to seven cases followed by age group of zero to twenty years which amounted to five cases, followed by age group of more than sixty years which amounted to four cases. Based on approximate height from which the fall occurred seventeen cases fell from the height of more than twenty feet, followed by nine cases which fell from the height of ten to twenty feet and six cases fell from the height of less than ten feet. The CT scan showed that eighteen cases had displaced spinal fractures followed by forteen cases which had undisplaced spinal fractures. Cord injury was seen in six cases. Based on the level of spine injury twenty six cases had lumbar spine injury, eleven

[Cervical myelopathy after low grade distortion of the cervical spine. Possible association with pre-existing spondylosis of the cervical spine].

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Aurich, M; Hofmann, G O; Gras, F M

2015-04-01

A patient with spondylosis deformans of the cervical spine with no neurological deficits developed rapidly progressive tetraparesis 1 day after a whiplash injury due to a car accident (rear end collision), although initially there were no clinical symptoms. Surgical decompression and spondylodesis led to relief of the neurological deficits. This case demonstrates that even a low grade whiplash injury (grade 1) can cause severe neurological symptoms later and that a degenerative disease of the spine is a predisposing factor.

Sheath rendezvous method: a novel distal protection technique during endovascular treatment of subclavian artery occlusions.

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Haraguchi, Takuya; Urasawa, Kazushi; Nakama, Tatsuya; Nakagawa, Yuya; Tan, Michinao; Koshida, Ryoji; Sato, Katsuhiko

2016-10-01

To describe an innovative distal protection technique, "sheath rendezvous method", during endovascular treatment for subclavian arterial occlusions. 4.5F and 6F guiding sheath were inserted from left brachial and common femoral artery, respectively. 0.014″ guidewire retrogradely passed through occlusion and into antegrade sheath to establish a pull-through system. 3.0 mm balloon was used to expand occlusion and anchor to deliver retrograde sheath into antegrade one. Both sheaths locked by balloon dilatation crossed occlusion until antegrade sheath passed over lesion. Balloon expandable stent was delivered within antegrade sheath. Sheath was removed, and stent was implanted. We obtained an excellent outcome without complications.

Dural ectasia of the optic nerve sheath: is it always benign?

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Berker Bakbak

2009-11-01

Full Text Available Berker Bakbak1, Hava Dönmez2, Tülay Kansu3, Hayyam Kiratli41Hacettepe University Institute of Neurological Sciences and Psychiatry, Neuro-ophthalmology Unit, Ankara, Turkey; 2Diskapi Yildirim Beyazid Education and Research Hospital Neurology Clinic, Ankara, Turkey; 3Hacettepe University Medical Faculty, Department of Neurology, Neuro-Ophthalmology Unit, Ankara, Turkey; 4Hacettepe University Medical Faculty, Department of Ophthalmology, Ocular Oncology Unit, Ankara, TurkeyAbstract: A 36-year-old woman with a 3-month history of progressive visual loss had papilledema, dilatation of the optic nerve sheaths and normal cerebrospinal fluid pressures. She was diagnosed as dural ectasia of the optic nerve sheaths and surgical decompression was performed. In this case report, severe visual loss is described as a serious complication of this rare disease and the importance of early surgical intervention is emphasized.Keywords: optic nerve, dural ectasia, meningocele

Incidence of enhancement of the optic nerve/sheath complex in fat-suppression orbit MRI

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Lee, Ho Kyu; Yoon, Kwon Ha; Choi, Choong Gon; Suh, Dae Chul [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

1995-04-15

To elucidate the incidence of Gd-DTPA enhancement of the optic nerve/sheath complex (ONC) in patients with various ophthalmopathies using fat-suppression MRI. Orbit MRI with fat-suppression technique (ChemSat) was performed in 58 patients with normal and various orbital lesions. The fat-suppression MR was done with and without Gd-DTPA injection in all cases. MR findings were reviewed retrospectively in a blind fashion with respect to presence or absence of contrast enhancement of the ONC. Contrast enhancement of the ONC was seen in 86% (6/7) of cavernous sinus lesions, 80% (8/10) of intraconal lesions excluding the ONC, 57% (16/28) of ONC lesions, 38% (3/8) of ocular lesions, and 2% (1/55) of normal orbits. The ONC enhancement was the most common in optic nerve/sheath tumors (10/10), and pseudotumors (6/6), cavernous sinus dural arteriovenous malformations (3/3) and cavernous sinus thrombosis (2/2), and less frequently seen in optic neuritis (3/14). Enhancement of the ONC may be seen in lesions of the cavernous sinus and orbit other than optic nerve/sheath lesion.

Benign and malignant neurogenic tumors of nerve sheath origin on FDG PET

International Nuclear Information System (INIS)

Yun, M. J.; Go, D. H.; Yoo, Y. H.; Shin, K. H.; Lee, J. D

2004-01-01

The differentiation between benign and malignant nerve sheath tumors is difficult based on conventional radiological imaging. This study was undertaken to investigate the value of FDG PET in distinguishing benign from malignant neurogenic tumors of nerve sheath origin. We performed a retrospective review of the medical record to select patients with nerve sheath tumors who had underdone FDG PET imaging. Fifteen patients (7F: 8M) with benign or malignant nerve sheath tumors were included in this study. Of the 15 patients, 9 were diagnosed with the known neurofibromatosis type I. A total of 19 nerve sheath tumors were included from the 15 patients. All patients had undergone FDG PET to evaluate for malignant potential of the known lesions. Images of FDG PET were semi-quantitatively analyzed and a region of interest (ROI) was placed over the area of the maximum FDG uptake and an average standardized uptake value was taken for final analysis. There were 5 malignant peripheral nerve sheath tumors, 5 schwannomas, and 9 neurofibromas. The mean SUV was 2 (ranged from 1.6 to 3.3) for schwannomas, 1.3 (0.7 to 2.5) for neurofibromas, and 8.4 (4.6 to 12.2) for malignant peripheral nerve sheath tumors. Of 14 benign tumors, all except one schwannoma showed a SUV less than 3. When a cutoff SUV of 4 was used to differentiate the nerve sheath tumors, all tumors were correctly classified as benign or malignant, respectively. Among the 9 patients diagnosed with neurofibromatosis type I. 4 had malignant peripheral nerve sheath tumors and FDG PET accurately detected all the 4 lesions with malignant transformation. According to our results, FDG PET seems to have a great potential for accurately characterizing benign versus malignant nerve sheath tumors. It appears to be extremely useful for patients with neurofibromatosis to localize the lesion with malignant transformation

Malpractice litigation following spine surgery.

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Daniels, Alan H; Ruttiman, Roy; Eltorai, Adam E M; DePasse, J Mason; Brea, Bielinsky A; Palumbo, Mark A

2017-10-01

OBJECTIVE Adverse events related to spine surgery sometimes lead to litigation. Few studies have evaluated the association between spine surgical complications and medical malpractice proceedings, outcomes, and awards. The aim of this study was to identify the most frequent causes of alleged malpractice in spine surgery and to gain insight into patient demographic and clinical characteristics associated with medical negligence litigation. METHODS A search for "spine surgery" spanning February 1988 to May 2015 was conducted utilizing the medicolegal research service VerdictSearch (ALM Media Properties, LLC). Demographic data for the plaintiff and defendant in addition to clinical data for the procedure and legal outcomes were examined. Spinal cord injury, anoxic/hypoxic brain injury, and death were classified as catastrophic complications; all other complications were classified as noncatastrophic. Both chi-square and t-tests were used to evaluate the effect of these variables on case outcomes and awards granted. RESULTS A total of 569 legal cases were examined; 335 cases were excluded due to irrelevance or insufficient information. Of the 234 cases included in this investigation, 54.2% (127 cases) resulted in a defendant ruling, 26.1% (61) in a plaintiff ruling, and 19.6% (46) in a settlement. The awards granted for plaintiff rulings ranged from $134,000 to $38,323,196 (mean $4,045,205 ± $6,804,647). Awards for settlements ranged from $125,000 to $9,000,000 (mean $1,930,278 ± $2,113,593), which was significantly less than plaintiff rulings (p = 0.022). Compared with cases without a delay in diagnosis of the complication, the cases with a diagnostic delay were more likely to result in a plaintiff verdict or settlement (42.9% vs 72.7%, p = 0.007) than a defense verdict, and were more likely to settle out of court (17.5% vs 40.9%, p = 0.008). Similarly, compared with cases without a delay in treatment of the complication, those with a therapeutic delay were more

A study on uncertainty by passage of time of stereotactic body radiation therapy for spine metastasis cancer

International Nuclear Information System (INIS)

Cho, Yong Wan; Kim, Joo Ho; Ahn, Seung Kwon; Lee, Sang Kyoo; Cho, Jeong Hee

2015-01-01

The purpose of this study was to determine the proper treatment time of stereotactic body radiation therapy for spine metastasis cancer by using the image guidance system of CyberKnife(Accuracy Incorporated, USA) which is able to correct movements of patients during the treatment. Fifty seven spine metastasis cancer patients who have stereotactic body radiation therapy of CyberKnife participate, 8 of them with cervical spine cancer, 26 of them with thoracic spine cancer, and 23 of them with lumbar spine cancer. X-ray images acquired during the treatment were classified by treatment site. From the starting point of treatment, motion tendency of patients is analyzed in each section which is divided into every 5 minutes. In case of cervical spine, there is sudden increase of variation in 15 minutes after the treatment starts in rotational direction. In case of thoracic spine, there is no significantly variable section. However, variation increases gradually with the passage of time so that it is assumed that noticeable value comes up in approximately 40 minutes. In case of lumbar spine, sharp increase of variation is seen in 20 minutes in translational and rotational direction. Without having corrections during the treatment, proper treatment time is considered as less than 15 minutes for cervical spine, 40 minutes for thoracic spine, and 20 minutes for lumbar spine. If treatment time is longer than these duration, additional patient alignments are required or PTV margin should be enlarged

A study on uncertainty by passage of time of stereotactic body radiation therapy for spine metastasis cancer

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Cho, Yong Wan; Kim, Joo Ho; Ahn, Seung Kwon; Lee, Sang Kyoo; Cho, Jeong Hee [Dept. of Radiation Oncology, Yonsei Cancer Center, Seoul (Korea, Republic of)

2015-06-15

The purpose of this study was to determine the proper treatment time of stereotactic body radiation therapy for spine metastasis cancer by using the image guidance system of CyberKnife(Accuracy Incorporated, USA) which is able to correct movements of patients during the treatment. Fifty seven spine metastasis cancer patients who have stereotactic body radiation therapy of CyberKnife participate, 8 of them with cervical spine cancer, 26 of them with thoracic spine cancer, and 23 of them with lumbar spine cancer. X-ray images acquired during the treatment were classified by treatment site. From the starting point of treatment, motion tendency of patients is analyzed in each section which is divided into every 5 minutes. In case of cervical spine, there is sudden increase of variation in 15 minutes after the treatment starts in rotational direction. In case of thoracic spine, there is no significantly variable section. However, variation increases gradually with the passage of time so that it is assumed that noticeable value comes up in approximately 40 minutes. In case of lumbar spine, sharp increase of variation is seen in 20 minutes in translational and rotational direction. Without having corrections during the treatment, proper treatment time is considered as less than 15 minutes for cervical spine, 40 minutes for thoracic spine, and 20 minutes for lumbar spine. If treatment time is longer than these duration, additional patient alignments are required or PTV margin should be enlarged.

Multimodal imaging in neurofibromatosis type 1-associated nerve sheath tumors; Multimodale Bildgebung bei Neurofibromatose-Typ-1-assoziierten Nervenscheidentumoren

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Salamon, J.; Adam, G. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Diagnostic and Interventional Radiology; Mautner, V.F. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Neurology; Derlin, T. [Hannover Medical School, Hannover (Germany). Dept. of Nuclear Medicine

2015-12-15

Neurofibromatosis type 1 (NF1) is a neurogenetic disorder. Individuals with NF1 may develop a variety of benign and malignant tumors of which peripheral nerve sheath tumors represent the most frequent entity. Plexiform neurofibromas may demonstrate a locally destructive growth pattern, may cause severe symptoms and may undergo malignant transformation into malignant peripheral nerve sheath tumors (MPNSTs). Whole-body magnetic resonance imaging (MRI) represents the reference standard for detection of soft tissue tumors in NF1. It allows for identification of individuals with plexiform neurofibromas, for assessment of local tumor extent, and for evaluation of whole-body tumor burden on T2-weighted imaging. Multiparametric MRI may provide a comprehensive characterization of different tissue properties of peripheral nerve sheath tumors, and may identify parameters associated with malignant transformation. Due to the absence of any radiation exposure, whole-body MRI may be used for serial follow-up of individuals with plexiform neurofibromas. {sup 18}F-fluorodeoxyglucose positron-emission-tomography (FDG PET/CT) allows a highly sensitive and specific detection of MPNST, and should be used in case of potential malignant transformation of a peripheral nerve sheath tumor. PET/CT provides a sensitive whole-body tumor staging. The use of contrast-enhanced CT for diagnosis of peripheral nerve sheath tumors is limited to special indications. To obtain the most precise readings, optimized examination protocols and dedicated radiologists and nuclear medicine physicians familiar with the complex and variable morphologies of peripheral nerve sheath tumors are required.

A Unique Case of Primary Ewing’s Sarcoma of the Cervical Spine in a 53-Year-Old Male: A Case Report and Review of the Literature

Directory of Open Access Journals (Sweden)

Marshall T. Holland

2015-01-01

Full Text Available Extraskeletal Ewing’s sarcoma (EES is a rare presentation, representing only 15% of all primary Ewing’s sarcoma cases. Even more uncommon is EES presenting as a primary focus in the spinal canal. These rapidly growing tumors often present with focal neurological symptoms of myelopathy or radiculopathy. There are no classic characteristic imaging findings and thus the physician must keep a high index of clinical suspicion. Diagnosis can only be definitively made by histopathological studies. In this report, we discuss a primary cervical spine EES in a 53-year-old man who presented with a two-month history of left upper extremity pain and acute onset of weakness. Imaging revealed a cervical spinal canal mass. After undergoing cervical decompression, histopathological examination confirmed a diagnosis of Ewing’s sarcoma. A literature search revealed fewer than 25 reported cases of primary cervical spine EES published in the past 15 years and only one report demonstrating this pathology in a patient older than 30 years of age age=38. Given the low incidence of this pathology presenting in this age group and the lack of treatment guidelines, each patient’s plan should be considered on a case-by-case basis until further studies are performed to determine optimal evidence based treatment.

A singular methodology to design cement sheath integrity exposed to steam stimulation

Energy Technology Data Exchange (ETDEWEB)

Garnier, A.; Saint-Marc, J. [Total SA, Paris (France); Bois, A.P. [CurisTec (France); Kermanac' h, Y. [Total E and P Canada Ltd., Calgary, AB (Canada)

2008-10-15

Oil well cements must be capable of providing zonal isolation as well as casing support and casing protection. However, steam assisted gravity drainage (SAGD) processes often place significant stresses on well casings and cement sheath boundaries. This paper presented a barrier design developed to ensure long-term cement sheath integrity in shallow reservoir conditions. Rock mechanics simulations were conducted in order to evaluate stresses in the field. The thermal gradient in well components was simulated. Thermo-hydraulic simulations of SAGD processes were conducted in order to evaluate thermal loadings and develop a series of temperature grids. Well trajectory, architecture and geology were considered, as well as formation properties, pore pressures, in situ stress states, and applied loadings. The results of both studies were then analyzed in order to determine the mechanical properties required by the cement in order to withstand thermal stresses. Various cement systems were then triaxial tested in order to validate simulation results. The method was used to design a cement system with low Young's modulus and high tensile strength at a well in the Joslyn field in Canada. The method is now being used by Total in fields throughout the world. 19 refs., 5 tabs., 16 figs.

Microscope sterility during spine surgery.

Science.gov (United States)

Bible, Jesse E; O'Neill, Kevin R; Crosby, Colin G; Schoenecker, Jonathan G; McGirt, Matthew J; Devin, Clinton J

2012-04-01

Prospective study. Assess the contamination rates of sterile microscope drapes after spine surgery. The use of the operating microscope has become more prevalent in certain spine procedures, providing superior magnification, visualization, and illumination of the operative field. However, it may represent an additional source of bacterial contamination and increase the risk of developing a postoperative infection. This study included 25 surgical spine cases performed by a single spine surgeon that required the use of the operative microscope. Sterile culture swabs were used to obtain samples from 7 defined locations on the microscope drape after its use during the operation. The undraped technician's console was sampled in each case as a positive control, and an additional 25 microscope drapes were swabbed immediately after they were applied to the microscope to obtain negative controls. Swab samples were assessed for bacterial growth on 5% sheep blood Columbia agar plates using a semiquantitative technique. No growth was observed on any of the 25 negative control drapes. In contrast, 100% of preoperative and 96% of postoperative positive controls demonstrated obvious contamination. In the postoperative group, all 7 sites of evaluation were found to be contaminated with rates of 12% to 44%. Four of the 7 evaluated locations were found to have significant contamination rates compared with negative controls, including the shafts of the optic eyepieces on the main surgeon side (24%, P = 0.022), "forehead" portion on both the main surgeon (24%, P = 0.022) and assistant sides (28%, P = 0.010), and "overhead" portion of the drape (44%, P = 0.0002). Bacterial contamination of the operative microscope was found to be significant after spine surgery. Contamination was more common around the optic eyepieces, likely due to inadvertent touching of unsterile portions. Similarly, all regions above the eyepieces also have a propensity for contamination because of unknown contact

Surgical treatment of gross posttraumatic deformations in thoracic spine

Directory of Open Access Journals (Sweden)

Aleksei E. Shul’ga

2017-10-01

Full Text Available Rigid severe post-traumatic thoracic spine deformities result from frequent, recent high-energy trauma in children with an increasing frequency due to a variety of reasons. These types of injuries are commonly followed by spinal cord anatomic injury; therefore, the treatment of these patients warrants special attention from the ethical viewpoint. Generally, the only indication for surgical intervention is spinal dysfunction. Considering this and the patients’ ordinary severe somatic state, surgical trauma should be minimized as much as possible. However, for adequate deformity correction, effective spine stabilization and restoration of liquorodynamics is necessary. Recent studies have reported the successful use of different methods of dorsal interventions (P/VCR in cases with unstable damages in children. Here, we present the case of a 15-year-old boy who underwent surgical treatment for coarse post-traumatic thoracic spine deformity with chronic fracture-dislocation of Th7 vertebra.

Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes

Energy Technology Data Exchange (ETDEWEB)

Grin, A. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

2014-09-01

The goal of this research is to provide durable and long-term water management solutions using exterior insulating sheathing as part of the water management system. It is possible to tape or seal the joints in insulating sheathing to create a drainage plane and even an air control layer. There exists the material durability component of the tape as well as the system durability component being the taped insulating sheathing as the drainage plane. This measure guideline provides best practice and product recommendations from the interviewed contractors and homebuilders who collectively have a vast amount of experience. Three significant issues were discussed with the group, which are required to make taped insulating sheathing a simple, long-term, and durable drainage plane: horizontal joints should be limited or eliminated wherever possible; where a horizontal joint exists use superior materials; and frequent installation inspection and regular trade training are required to maintain proper installation.

Pathologic evaluation of the cervical spine following surgical and chiropractic interventions.

Science.gov (United States)

Matshes, Evan W; Joseph, Jeffrey

2012-01-01

When patients die after chiropractic or surgical interventions of the cervical spine, pathologists tasked with the autopsy are frequently overwhelmed by the complicated anatomy, laborious dissections, complex operative procedures and surgical hardware, and the necessity to differentiate artifacts from trauma and disease. However, abundant data can be obtained from careful evaluation of the cervical spine in situ; extensive postmortem diagnostic imaging procedures; detailed dissections of the removed, formalin-fixed and decalcified spine; and histology. This study presents a regimented, stepwise approach to the evaluation of the cervical spine in these difficult cases, promotes uniform assessment, facilitates diagnoses, and supports the accumulation of otherwise hard-to-come-by reference material that can be of value in future cases. The resultant detailed autopsy findings may prove useful in the medico-legal death investigation process. Autopsy findings may also be of great value to health care providers involved in quality assurance processes. © 2011 American Academy of Forensic Sciences.

Multilevel brown tumors of the spine in a patient with severe secondary hyperparathyroidism A case report and review of the literature.

Science.gov (United States)

Salamone, Daniela; Muresan, Simona; Muresan, Mircea; Neagoe, Radu

2016-03-31

The brown tumour is an extreme form of osteitis fibrosa cystica, representing a serious complication of the advanced primary or secondary hyperparathyroidism. It occurs in settings of high levels parathyroid hormone, like in primary or secondary hyperparathyroidism, with a frequency of 3-4% and 1.5-13% respectively, usually affecting young people. The authors report a case of a 45 years old woman on long-term hemodialysis, with severe secondary hyperparathyroidism. The main clinical complaints were neck pain, lower thoraco-lumbar back pain, persistent left groin pain, and bilateral lower extremities weakness. The computed tomography scan revealed multiple spine brown tumors affecting the cervical, thoracic and lumbar level. After an initial partial response to the treatment of two years with Cinacalcet, a deterioration of the secondary hyperparathyroidism occurred (hypercalcemia, hyperphosphatemia) and the patient was referred for parathyroidectomy. The patient underwent total parathyroidectomy with auto-transplantation, with a positive postoperative result. Secondary hyperparathyroidism can lead, during its course, to osteolytic bone lesions called brown tumors. If the medical treatment fails, the surgical removal of the parathyroid glands with autotransplant remains the only treatment of the bone lesions progression. Reviewing the relevant literature in English (until March 2015), we found 24 cases of symptomatic vertebral brown tumors. To the authors' knowledge, this is the first case which describes a multilevel spine involvement (more than two), and the fifth describing a cervical localization. Hypocalcaemia, Secondary hyperparathyroidism, Spine brown tumors.

Synovial sarcoma mimicking benign peripheral nerve sheath tumor

Energy Technology Data Exchange (ETDEWEB)

Larque, Ana B.; Nielsen, G.P.; Chebib, Ivan [Massachusetts General Hospital and Harvard Medical School, Department of Pathology, Boston, MA (United States); Bredella, Miriam A. [Massachusetts General Hospital and Harvard Medical School, Department of Radiology, Boston, MA (United States)

2017-11-15

To assess the radiographic and clinicopathologic features of synovial sarcoma of the nerve that were clinically or radiologically interpreted as benign peripheral nerve sheath tumor. Five patients with synovial sarcoma arising from the peripheral nerve and interpreted clinically and radiologically as peripheral nerve sheath tumors were identified. Clinicopathologic and imaging features were evaluated. There were three females and two males, ranging in age from 28 to 50 (mean 35.8) years. Most patients (4/5) complained of a mass, discomfort or pain. MR images demonstrated a heterogeneous, enhancing, soft tissue mass contiguous with the neurovascular bundle. On histologic examination, most tumors were monophasic synovial sarcoma (4/5). At the time of surgery, all tumors were noted to arise along or within a peripheral nerve. All patients were alive with no evidence of disease with median follow-up of 44 (range 32-237) months. For comparison, approximately 775 benign peripheral nerve sheath tumors of the extremities were identified during the same time period. Primary synovial sarcoma of the nerve can mimic peripheral nerve sheath tumors clinically and on imaging and should be included in the differential diagnosis for tumors arising from peripheral nerves. (orig.)

Primary optic nerve sheath meningioma

Energy Technology Data Exchange (ETDEWEB)

Jeremic, Branislav [International Atomic Energy Agency, Vienna (Austria); Pitz, Susanne (eds.) [University Eye Hospital, Mainz (Germany)

2008-07-01

Optic nerve sheath meningioma (ONSM) is a rare tumour. Cases are usually separated into primary ONSM, which arises either intraorbitally or, less commonly, intracanalicularly, and secondary ONSM, which arises intracranially and subsequently invades the optic canal and orbit. This is the first book to cover all important aspects of the diagnosis and treatment of primary ONSM. After a general introduction, individual chapters discuss the clinical presentation, clinical examination and diagnosis, imaging, and histology. Treatment options are then addressed in detail, with special emphasis on external beam radiation therapy, and in particular stereotactic fractionated radiation therapy. The latter has recently produced consistently good results and is now considered the emerging treatment of choice for the vast majority of patients with primary ONSM. This well-illustrated book will prove invaluable to all practitioners who encounter primary ONSM in their clinical work. (orig.)

Properties of plasma sheath with ion temperature in magnetic fusion devices

International Nuclear Information System (INIS)

Liu Jinyuan; Wang Feng; Sun Jizhong

2011-01-01

The plasma sheath properties in a strong magnetic field are investigated in this work using a steady state two-fluid model. The motion of ions is affected heavily by the strong magnetic field in fusion devices; meanwhile, the effect of ion temperature cannot be neglected for the plasma in such devices. A criterion for the plasma sheath in a strong magnetic field, which differs from the well-known Bohm criterion for low temperature plasma sheath, is established theoretically with a fluid model. The fluid model is then solved numerically to obtain detailed sheath information under different ion temperatures, plasma densities, and magnetic field strengths.

Partial-thickness macular hole in vitreomacular traction syndrome: a case report and review of the literature

Directory of Open Access Journals (Sweden)

Al Sabti Khalid

2010-01-01

Full Text Available Abstract Introduction Vitreomacular traction syndrome has recently been recognized as a distinct clinical condition. It may lead to many complications, such as cystoid macular edema, macular pucker formation, tractional macular detachment, and full-thickness macular hole formation. Case presentation We report a case of vitreomacular traction syndrome with eccentric traction at the macula and a partial-thickness macular hole in a 63-year-old Pakistani Punjabi man. The patient was evaluated using optical coherence tomography, and he underwent a successful pars plana vitrectomy. After the operation, his foveal contour regained normal configuration, and his visual acuity improved from 20/60 to 20/30. Conclusions Pars plana vitrectomy prevents the progression of a partial thickness macular hole in vitreomacular traction syndrome. The relief of traction by vitrectomy restores foveal anatomy and visual acuity in this condition.

Plasma sheath axial phase dynamics in coaxial device

Energy Technology Data Exchange (ETDEWEB)

Soliman, H.M. (Plasma Physics Dept., NRC, Atomic Energy Authority, Cairo (Egypt)); Masoud, M.M. (Plasma Physics Dept., NRC, Atomic Energy Authority, Cairo (Egypt))

1994-10-01

The study of the plasma sheath dynamics in the axial phase has been carried out in a 3 kJ coaxial system of Mather type for two different inner electrode (IE) lengths, 20 cm and 31.5 cm. For both lengths, measurements showed that the plasma sheath is splitted into two layers at the breech, which is referred to as a shock front and its magnetic piston. It has been found that the two layers of the plasma current sheath rotate around the inner electrode. At the muzzle the back layer reverse its rotation direction due to the magnetic field structure of the system. Results showed that the axial velocity of the first layer is greater than the second one all over the axial phase within the range between 1.4 and 1.7. (orig.).

Plasma sheath axial phase dynamics in coaxial device

International Nuclear Information System (INIS)

Soliman, H.M.; Masoud, M.M.

1994-01-01

The study of the plasma sheath dynamics in the axial phase has been carried out in a 3 kJ coaxial system of Mather type for two different inner electrode (IE) lengths, 20 cm and 31.5 cm. For both lengths, measurements showed that the plasma sheath is splitted into two layers at the breech, which is referred to as a shock front and its magnetic piston. It has been found that the two layers of the plasma current sheath rotate around the inner electrode. At the muzzle the back layer reverse its rotation direction due to the magnetic field structure of the system. Results showed that the axial velocity of the first layer is greater than the second one all over the axial phase within the range between 1.4 and 1.7. (orig.)

Optic Nerve Sheath Mechanics in VIIP Syndrome

Science.gov (United States)

Raykin, Julia; Forte, Taylor E.; Wang, Roy; Feola, Andrew; Samuels, Brian; Myers, Jerry; Nelson, Emily; Gleason, Rudy; Ethier, C. Ross

2016-01-01

Visual Impairment Intracranial Pressure (VIIP) syndrome is a major concern in current space medicine research. While the exact pathology of VIIP is not yet known, it is hypothesized that the microgravity-induced cephalad fluid shift increases intracranial pressure (ICP) and drives remodeling of the optic nerve sheath. To investigate this possibility, we are culturing optic nerve sheath dura mater samples under different pressures and investigating changes in tissue composition. To interpret results from this work, it is essential to first understand the biomechanical response of the optic nerve sheath dura mater to loading. Here, we investigated the effects of mechanical loading on the porcine optic nerve sheath.Porcine optic nerves (number: 6) were obtained immediately after death from a local abattoir. The optic nerve sheath (dura mater) was isolated from the optic nerve proper, leaving a hollow cylinder of connective tissue that was used for biomechanical characterization. We developed a custom mechanical testing system that allowed for unconfined lengthening, twisting, and circumferential distension of the dura mater during inflation and under fixed axial loading. To determine the effects of variations in ICP, the sample was inflated (0-60 millimeters Hg) and circumferential distension was simultaneously recorded. These tests were performed under variable axial loads (0.6 grams - 5.6 grams at increments of 1 gram) by attaching different weights to one end of the dura mater. Results and Conclusions: The samples demonstrated nonlinear behavior, similar to other soft connective tissue (Figure 1). Large increases in diameter were observed at lower transmural pressures (approximately 0 to 5 millimeters Hg), whereas only small diameter changes were observed at higher pressures. Particularly interesting was the existence of a cross-over point at a pressure of approximately 11 millimeters Hg. At this pressure, the same diameter is obtained for all axial loads applied

Conspicuous carotenoid-based pelvic spine ornament in three-spined stickleback populations—occurrence and inheritance

Directory of Open Access Journals (Sweden)

CR Amundsen

2015-04-01

Full Text Available Reports on reddish carotenoid-based ornaments in female three-spined sticklebacks (Gasterosteus aculeatus are few, despite the large interest in the species’ behaviour, ornamentation, morphology and evolution. We sampled sticklebacks from 17 sites in north-western Europe in this first extensive study on the occurrence of carotenoid-based female pelvic spines and throat ornaments. The field results showed that females, and males, with reddish spines were found in all 17 populations. Specimens of both sexes with conspicuous red spines were found in several of the sites. The pelvic spines of males were more intensely red compared to the females’ spines, and large specimens were more red than small ones. Fish infected with the tapeworm (Schistocephalus solidus had drabber spines than uninfected fish. Both sexes had red spines both during and after the spawning period, but the intensity of the red colour was more exaggerated during the spawning period. As opposed to pelvic spines, no sign of red colour at the throat was observed in any female from any of the 17 populations. A rearing experiment was carried out to estimate a potential genetic component of the pelvic spine ornament by artificial crossing and rearing of 15 family groups during a 12 months period. The results indicated that the genetic component of the red colour at the spines was low or close to zero. Although reddish pelvic spines seem common in populations of stickleback, the potential adaptive function of the reddish pelvic spines remains largely unexplained.

Carotid Artery Injury in Anterior Cervical Spine Surgery: Multicenter Cohort Study and Literature Review.

Science.gov (United States)

Härtl, Roger; Alimi, Marjan; Abdelatif Boukebir, Mohamed; Berlin, Connor D; Navarro-Ramirez, Rodrigo; Arnold, Paul M; Fehlings, Michael G; Mroz, Thomas E; Riew, K Daniel

2017-04-01

Retrospective study and literature review. To provide more comprehensive data about carotid artery injury (CAI) or cerebrovascular accident (CVA) related to anterior cervical spine surgery. We conducted a retrospective, multicenter, case series study involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network. Medical records of 17 625 patients who went through cervical spine surgery (levels from C2 to C7) between January 1, 2005, and December 31, 2011, were analyzed. Also, we performed a literature review using Medline and PubMed databases. The following terms were used alone, and in combination, to search for relevant articles: cervical, spine, surgery, complication, iatrogenic, carotid artery, injury, cerebrovascular accident, CVA, and carotid stenosis. Among 17 625 patients that were analyzed, no cases were reported to experienced CAI or CVA after cervical spine surgery. Nevertheless, in our PubMed search we found 157 articles, but only 5 articles matched our study objective criteria; 2 cases were reported to present CAI and 3 cases presented CVA. CAI and CVA related to anterior cervical spine surgeries are extremely rare. We were not able to find neither in our retrospective study nor in our literature research a correlation between the type or length of anterior cervical spine procedure with CVA or CAI complications. However, surgeons should be aware of the possibility of vascular complications and minimize intraoperative direct vascular manipulations or retraction. Preoperative screening for underlying vascular pathology and risk factors is also important.

INDICATION OF THE BLACK HOLE POWERED JET IN M87 BY VSOP OBSERVATIONS

Energy Technology Data Exchange (ETDEWEB)

Asada, Keiichi; Nakamura, Masanori; Pu, Hung-Yi, E-mail: asada@asiaa.sinica.edu.tw, E-mail: nakamura@asiaa.sinica.edu.tw, E-mail: hypu@asiaa.sinica.edu.tw [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China)

2016-12-10

In order to study the collimation and acceleration mechanism of relativistic jets, the jet streamline of M87 at milliarcsecond scale is extensively investigated with images from VSOP observations at 1.6 and 5 GHz. Thanks to the higher angular resolution of VSOP, especially in the direction transverse to the jet, we resolved the jet streamline into three ridgelines at the scale of milli arcseconds. While the properties of the outer two ridgelines are in good agreement with those measured in previous observations and can be expressed by one power-law line with a power law index of 1.7, an inner ridgeline is clearly observed for the first time. We compared the measured size with the outermost streamline expected by Blandford and Znajek's parabolic solutions, which are anchored at the event horizon, with different black hole spin parameters. We revealed that the observed inner ridgeline is narrower than the prediction, suggesting the origin of the inner ridgeline to be part of a spine originating from the spinning black hole. The inner ridgeline becomes very dim at large distances from the central engine at 5 GHz. We considered two possible cases for this; Doppler beaming and/or radiative cooling. Either case seems to be reasonable for its explanation, and future multi-frequency observations will discriminate those two possibilities.

A Case of Malignant Peripheral Nerve Sheath Tumor with Rhabdomyoblastic Differentiation: Malignant Triton Tumor

Directory of Open Access Journals (Sweden)

Kenichiro Mae

2013-12-01

Full Text Available Malignant peripheral nerve sheath tumors (MPNST constitute a rare variety of soft tissue sarcomas thought to originate from Schwann cells or pluripotent cells of the neural crest. Malignant triton tumor (MTT, a very rare, highly aggressive soft tissue tumor, is a subgroup of MPNST and is comprised of malignant Schwann cells coexisting with malignant rhabdomyoblasts. We herein report the case of a 24-year-old man who presented a subcutaneous mass in his right thigh. The mass was removed surgically in its entirety and radiation therapy was applied locally to prevent tumor regrowth. Nonetheless, the patient died 10 months after surgery from metastases to the lung and brain. He presented neither cafe-au-lait spots nor cutaneous neurofibromas. The histopathology showed a transition from a neurofibroma to an MTT, making this the second report of an MTT arising from a neurofibroma without neurofibromatosis type 1, an autosomal dominant disorder with which 50-70% of tumors reported in previous studies were associated. A histopathological examination using immunostaining with desmin confirmed this diagnosis. MTT has a poorer prognosis than MPNST and should therefore be regarded as a distinct clinical entity.

Whole spine MRI in the assessment of acute vertebral body trauma

International Nuclear Information System (INIS)

Green, R.A.R.; Saifuddin, A.

2004-01-01

To determine the incidence and types of multilevel vertebral body injury in association with acute spinal trauma as assessed by whole spine MRI. All acute admissions to a regional spinal injury unit had whole spine MRI carried out, to detect occult vertebral body injury. Two radiologists assessed 127 cases prospectively, over a period of 3 years. All cases had T2-weighted sagittal imaging of the whole spine (where possible using a T2-weighted fat-suppressed sequence), with T1-weighted imaging in both sagittal and axial planes covering the primary injury. The incidence of secondary injury (defined as either bone bruising, wedge compression fracture or burst fracture) was determined and defined by type, site and relationship to the primary injury. Seventy-seven per cent of cases had a secondary injury level. Of these, bone bruising was the commonest but often occurred in combination with secondary wedge compression fracture or burst fracture. MRI detected 27 non-contiguous wedge compression fractures and 16 non-contiguous burst fractures, giving an incidence of secondary level, non-contiguous fracture of approximately 34%. A higher frequency of secondary vertebral body injury may be defined by MRI than has been described in previous studies based on radiographic evaluation of the whole spine. Whole spine MRI in assessment for occult vertebral body fracture enables increased confidence in the conservative or surgical management of patients with severe spinal injury. (orig.)

Iatrogenic Spinal Cord Injury Resulting From Cervical Spine Surgery.

Science.gov (United States)

Daniels, Alan H; Hart, Robert A; Hilibrand, Alan S; Fish, David E; Wang, Jeffrey C; Lord, Elizabeth L; Buser, Zorica; Tortolani, P Justin; Stroh, D Alex; Nassr, Ahmad; Currier, Bradford L; Sebastian, Arjun S; Arnold, Paul M; Fehlings, Michael G; Mroz, Thomas E; Riew, K Daniel

2017-04-01

Retrospective cohort study of prospectively collected data. To examine the incidence of iatrogenic spinal cord injury following elective cervical spine surgery. A retrospective multicenter case series study involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network was conducted. Medical records for 17 625 patients who received cervical spine surgery (levels from C2 to C7) between January 1, 2005, and December 31, 2011, were reviewed to identify occurrence of iatrogenic spinal cord injury. In total, 3 cases of iatrogenic spinal cord injury following cervical spine surgery were identified. Institutional incidence rates ranged from 0.0% to 0.24%. Of the 3 patients with quadriplegia, one underwent anterior-only surgery with 2-level cervical corpectomy, one underwent anterior surgery with corpectomy in addition to posterior surgery, and one underwent posterior decompression and fusion surgery alone. One patient had complete neurologic recovery, one partially recovered, and one did not recover motor function. Iatrogenic spinal cord injury following cervical spine surgery is a rare and devastating adverse event. No standard protocol exists that can guarantee prevention of this complication, and there is a lack of consensus regarding evaluation and treatment when it does occur. Emergent imaging with magnetic resonance imaging or computed tomography myelography to evaluate for compressive etiology or malpositioned instrumentation and avoidance of hypotension should be performed in cases of intraoperative and postoperative spinal cord injury.

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Bone mineral density changes of lumbar spine and femur in osteoporotic patient treated with bisphosphonates and beta-hydroxy-beta-methylbutyrate (HMB): Case report.

Science.gov (United States)

Tatara, Marcin R; Krupski, Witold; Majer-Dziedzic, Barbara

2017-10-01

Currently available approaches to osteoporosis treatment include application of antiresorptive and anabolic agents influencing bone tissue metabolism. The aim of the study was to present bone mineral density (BMD) changes of lumbar spine in osteoporotic patient treated with bisphosphonates such as ibandronic acid and pamidronic acid, and beta-hydroxy-beta-methylbutyrate (HMB). BMD and volumetric BMD (vBMD) of lumbar spine were measured during the 6 year observation period with the use of dual-energy X-ray absorptiometry (DEXA) and quantitative computed tomography (QCT). The described case report of osteoporotic patient with family history of severe osteoporosis has shown site-dependent response of bone tissue to antiosteoporotic treatment with bisphosphonates. Twenty-five-month treatment with ibandronic acid improved proximal femur BMD with relatively poor effects on lumbar spine BMD. Over 15-month therapy with pamidronic acid was effective to improve lumbar spine BMD, while in the proximal femur the treatment was not effective. A total of 61-week long oral administration with calcium salt of HMB improved vBMD of lumbar spine in the trabecular and cortical bone compartments when monitored by QCT. Positive effects of nearly 2.5 year HMB treatment on BMD of lumbar spine and femur in the patient were also confirmed using DEXA method. The results obtained indicate that HMB may be applied for the effective treatment of osteoporosis in humans. Further studies on wider human population are recommended to evaluate mechanisms influencing bone tissue metabolism by HMB.

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Lifescience Database Archive (English)

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File list: Pol.Neu.05.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

Lifescience Database Archive (English)

Full Text Available Pol.Neu.05.AllAg.Nerve_Sheath_Neoplasms mm9 RNA polymerase Neural Nerve Sheath Neop...lasms http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Neu.05.AllAg.Nerve_Sheath_Neoplasms.bed ...

Percutaneous spine injection: considerations for improving treatment

International Nuclear Information System (INIS)

Lee, Joon Woo; Kim, Sung Hyun; Lee, In Sook; Choi, Jung Ah; Yoon, Chang Jin; Hwang, Sung Il; Kang, Heung Sik; Choi, Ja Young; Koh, Young Hwan; Hong, Sung Hwan

2005-01-01

To discuss the causes of treatment failure in percutaneous spine injections for low back pain or radiculopathy by analyzing patients who have experienced negative treatment effect on their first visit and a positive treatment effect on their second visit. The authors reviewed the cases of 24 patients who visited the pain intervention outpatient department in our hospital due to back pain or radiculopathy. All patients reviewed experienced a negative treatment effect following their first spine injection, but a positive treatment effect following the second injection. The dates of the cases range from June 2003 to May 2004. Two radiologists analyzed the possible causes of the negative treatment effect following the first injection therapies by considering clinical aspects as well as reviewing radiological images. The most common condition was the presence of the change in the level of the second selective nerve root block (n=13). In seven cases, the methods for administering the injections were changed to facet block (n=2), midline epidural block (n=1), selective nerve root block (n=3) and caudal epidural block (n=1). In four cases, there were no changes in the methods for administering the injections nor were there any changes in the level of the selective nerve root block between first and second visit. In those cases, after reviewing spot radiographs performed during injection, we attributed the causes of failure of injection therapy to an inappropriate distribution of drugs. We can improve the effect of percutaneous spine injections for low back pain or radioculopathy by determining the exact level of perineural root block, trying alternative methods, and insuring a good distribution of the injected drugs

Use of thoracic spine thrust manipulation for neck pain and headache in a patient following multiple-level anterior cervical discectomy and fusion: a case report.

Science.gov (United States)

Salvatori, Renata; Rowe, Robert H; Osborne, Raine; Beneciuk, Jason M

2014-06-01

Case report. Thoracic spine thrust manipulation has been shown to be an effective intervention for individuals experiencing mechanical neck pain. The patient was a 46-year-old woman referred to outpatient physical therapy 2 months following multiple-level anterior cervical discectomy and fusion. At initial evaluation, primary symptoms consisted of frequent headaches, neck pain, intermittent referred right elbow pain, and muscle fatigue localized to the right cervical and upper thoracic spine regions. Initial examination findings included decreased passive joint mobility of the thoracic spine, limited cervical range of motion, and limited right shoulder strength. Outcome measures consisted of the numeric pain rating scale, the Neck Disability Index, and the global rating of change scale. Treatment consisted of a combination of manual therapy techniques aimed at the thoracic spine, therapeutic exercises for the upper quarter, and patient education, including a home exercise program, over a 6-week episode of care. Immediate reductions in cervical-region pain (mean ± SD, 2.0 ± 1.1) and headache (2.0 ± 1.3) intensity were reported every treatment session immediately following thoracic spine thrust manipulation. At discharge, the patient reported 0/10 cervical pain and headache symptoms during all work-related activities. From initial assessment to discharge, Neck Disability Index scores improved from 46% to 16%, with an associated global rating of change scale score of +7 ("a very great deal better"). This case report describes the immediate and short-term clinical outcomes for a patient presenting with symptoms of neck pain and headache following anterior cervical discectomy and fusion surgical intervention. Clinical rationale and patient preference aided the decision to incorporate thoracic spine thrust manipulation as a treatment for this patient. Level of Evidence Therapy, level 4.

Thoracic spine pain

Directory of Open Access Journals (Sweden)

Aleksey Ivanovich Isaikin

2013-01-01

Full Text Available Thoracic spine pain, or thoracalgia, is one of the common reasons for seeking for medical advice. The epidemiology and semiotics of pain in the thoracic spine unlike in those in the cervical and lumbar spine have not been inadequately studied. The causes of thoracic spine pain are varied: diseases of the cardiovascular, gastrointestinal, pulmonary, and renal systems, injuries to the musculoskeletal structures of the cervical and thoracic portions, which require a thorough differential diagnosis. Facet, costotransverse, and costovertebral joint injuries and myofascial syndrome are the most common causes of musculoskeletal (nonspecific pain in the thoracic spine. True radicular pain is rarely encountered. Traditionally, treatment for thoracalgia includes a combination of non-drug and drug therapies. The cyclooxygenase 2 inhibitor meloxicam (movalis may be the drug of choice in the treatment of musculoskeletal pain.

Shear flow instability in a partially-ionized plasma sheath around a fast-moving vehicle

International Nuclear Information System (INIS)

Sotnikov, V. I.; Mudaliar, S.; Genoni, T. C.; Rose, D. V.; Oliver, B. V.; Mehlhorn, T. A.

2011-01-01

The stability of ion acoustic waves in a sheared-flow, partially-ionized compressible plasma sheath around a fast-moving vehicle in the upper atmosphere, is described and evaluated for different flow profiles. In a compressible plasma with shear flow, instability occurs for any velocity profile, not just for profiles with an inflection point. A second-order differential equation for the electrostatic potential of excited ion acoustic waves in the presence of electron and ion collisions with neutrals is derived and solved numerically using a shooting method with boundary conditions appropriate for a finite thickness sheath in contact with the vehicle. We consider three different velocity flow profiles and find that in all cases that neutral collisions can completely suppress the instability.

Evaluation of the Effusion within Biceps Long Head Tendon Sheath Using Ultrasonography

Science.gov (United States)

Park, In; Lee, Hyo-Jin; Kim, Sung-Eun; Bae, Sung-Ho; Lee, Kwang-Yeol; Park, Kwang-Sun

2015-01-01

Background Many shoulder diseases are related to glenohumeral joint synovitis and effusion. The purpose of the present study is to detect effusion within the biceps long head tendon sheath as the sign of glenohumeral joint synovitis using ultrasonography, and to evaluate the clinical meaning of effusion within the biceps long head tendon sheath. Methods A consecutive series of 569 patients who underwent ultrasonography for shoulder pain were reviewed retrospectively and ultimately, 303 patients were included. The authors evaluated the incidence and amount of the effusion within the biceps long head tendon sheath on the ultrasonographic short axis view. Furthermore, the authors evaluated the correlation between the amount of effusion within the biceps long head tendon sheath and the range of motion and the functional score. Results The effusion within the biceps long head tendon sheath was detected in 58.42% of the patients studied: 69.23% in adhesive capsulitis, 56.69% in rotator cuff tear, 41.03% in calcific tendinitis, and 33.33% in biceps tendinitis. The average amount of the effusion within the biceps long head tendon sheath was 1.7 ± 1.6 mm, and it was measured to be the largest in adhesive capsulitis. The amount of effusion within biceps long head tendon sheath showed a moderate to high degree of correlation with the range of motion, and a low degree of correlation with the functional score and visual analogue scale for pain in each type of shoulder disease. Conclusions The effusion within the biceps long head tendon sheath is closely related to the range of motion and clinical scores in patients with painful shoulders. Ultrasonographic detection of the effusion within the biceps long head tendon sheath might be a simple and easy method to evaluate shoulder function. PMID:26330958

Design of Cold-Formed Steel Screw Connections with Gypsum Sheathing at Ambient and Elevated Temperatures

Directory of Open Access Journals (Sweden)

Wei Chen

2016-09-01

Full Text Available Load-bearing cold-formed steel (CFS walls sheathed with double layers of gypsum plasterboard on both sides have demonstrated good fire resistance and attracted increasing interest for use in mid-rise CFS structures. As the main connection method, screw connections between CFS and gypsum sheathing play an important role in both the structural design and fire resistance of this wall system. However, studies on the mechanical behavior of screw connections with double-layer gypsum sheathing are still limited. In this study, 200 monotonic tests of screw connections with single- or double-layer gypsum sheathing at both ambient and elevated temperatures were conducted. The failure of screw connections with double-layer gypsum sheathing in shear was different from that of single-layer gypsum sheathing connections at ambient temperature, and it could be described as the breaking of the loaded sheathing edge combined with significant screw tilting and the loaded sheathing edge flexing fracture. However, the screw tilting and flexing fracture of the loaded sheathing edge gradually disappear at elevated temperatures. In addition, the influence of the loaded edge distance, double-layer sheathing and elevated temperatures is discussed in detail with clear conclusions. A unified design formula for the shear strength of screw connections with gypsum sheathing is proposed for ambient and elevated temperatures with adequate accuracy. A simplified load–displacement model with the post-peak branch is developed to evaluate the load–displacement response of screw connections with gypsum sheathing at ambient and elevated temperatures.

Embedded cladding surface thermocouples on Zircaloy-sheathed heater rods

International Nuclear Information System (INIS)

Wilkins, S.C.

1977-06-01

Titanium-sheathed Type K thermocouples embedded in the cladding wall of zircaloy-sheathed heater rods are described. These thermocouples constitute part of a program intended to characterize the uncertainty of measurements made by surface-mounted cladding thermocouples on nuclear fuel rods. Fabrication and installation detail, and laboratory testing of sample thermocouple installations are included

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File list: ALL.Neu.05.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

Lifescience Database Archive (English)

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A technical case report on use of tubular retractors for anterior cervical spine surgery.

Science.gov (United States)

Kulkarni, Arvind G; Patel, Ankit; Ankith, N V

2017-12-19

The authors put-forth this technical report to establish the feasibility of performing an anterior cervical corpectomy and fusion (ACCF) and a two-level anterior cervical discectomy and fusion (ACDF) using a minimally invasive approach with tubular retractors. First case: cervical spondylotic myelopathy secondary to a large postero-inferiorly migrated disc treated with corpectomy and reconstruction with a mesh cage and locking plate. Second case: cervical disc herniation with radiculopathy treated with a two-level ACDF. Both cases were operated with minimally invasive approach with tubular retractor using a single incision. Technical aspects and clinical outcomes have been reported. No intra or post-operative complications were encountered. Intra-operative blood loss was negligible. The patients had a cosmetic scar on healing. Standard procedure of placement of tubular retractors is sufficient for adequate surgical exposure with minimal invasiveness. Minimally invasive approach to anterior cervical spine with tubular retractors is feasible. This is the first report on use of minimally invasive approach for ACCF and two-level ACDF.

Spontaneous rectus sheath hematoma: The utility of CT angiography

Directory of Open Access Journals (Sweden)

Antonio Pierro, MD

2018-04-01

Full Text Available We described the utility of computed tomography (CT angiography in detection of bleeding vessels for a rapid percutaneous arterial embolization of the spontaneous rectus sheath hematoma. A 70-year-old woman comes to our attention with acute abdominal pain and a low hemoglobin level. An unenhanced CT was performed demonstrating a large rectus sheath hematoma. A conservative management was initially established. Despite this therapy, the abdominal pain increased together with a further decrease of hemoglobin values. A CT angiography was then performed, demonstrating an active bleeding within the hematoma and addressing the patient to a rapid percutaneous arterial embolization. Keywords: Rectus sheath hematoma, Acute abdomen, Arterial embolization, CT angiography, Active bleeding

A case of desmoplastic melanoma that was difficult to distinguish from malignant peripheral nerve sheath tumor

Directory of Open Access Journals (Sweden)

Kenji Yorita

2018-03-01

Full Text Available The clinical and pathological diagnosis of desmoplastic melanoma is difficult, because almost 50% of desmoplastic melanoma cases involve non-pigmented lesions and the tumor cells can resemble fibroblasts or Schwannian cells based on their frequent amelanotic features. Moreover, desmoplastic melanoma typically has low positive rates for melanoma markers, with the exception of the S-100 protein. We report the case of an 81-year-old Japanese man with an 8-mm desmoplastic melanoma. He initially noticed a painless and non-pigmented skin lesion that did not grow noticeably for 6 months. It was unlikely that he had von Recklinghausen disease, and the mass was initially considered a dermatofibroma. Excisional biopsy revealed an intradermal mass, with the superficial portion mimicking neurofibroma and the deeper portion exhibiting nodular growth of sarcomatoid spindle cells. The tumor region lacked intradermal proliferation of atypical melanocytic cells, intracytoplasmic melanin, and expression of melanoma markers (except S-100 protein and Sox10. Although a malignant peripheral nerve sheath tumor derived from neurofibroma was possible, the slow growth with diffuse and strong immunoreactivity to the S-100 protein and Sox10 favored a diagnosis of desmoplastic melanoma. Pathologists should recognize that desmoplastic melanoma may not involve in situ lesions or the immunohistochemical expression of standard melanoma markers.

Minimally invasive spine surgery: Hurdles to be crossed

Directory of Open Access Journals (Sweden)

Mahesh Bijjawara

2014-01-01

Full Text Available MISS as a concept is noble and all surgeons need to address and minimize the surgical morbidity for better results. However, we need to be cautions and not fall prey into accepting that minimally invasive spine surgery can be done only when certain metal access systems are used. Minimally invasive spine surgery (MISS has come a long way since the description of endoscopic discectomy in 1997 and minimally invasive TLIF (mTLIF in 2003. Today there is credible evidence (though not level-I that MISS has comparable results to open spine surgery with the advantage of early postoperative recovery and decreased blood loss and infection rates. However, apart from decreasing the muscle trauma and decreasing the muscle dissection during multilevel open spinal instrumentation, there has been little contribution to address the other morbidity parameters like operative time , blood loss , access to decompression and atraumatic neural tissue handling with the existing MISS technologies. Since all these parameters contribute to a greater degree than posterior muscle trauma for the overall surgical morbidity, we as surgeons need to introspect before we accept the concept of minimally invasive spine surgery being reduced to surgeries performed with a few tubular retractors. A spine surgeon needs to constantly improve his skills and techniques so that he can minimize blood loss, minimize traumatic neural tissue handling and minimizing operative time without compromising on the surgical goals. These measures actually contribute far more, to decrease the morbidity than approach related muscle damage alone. Minimally invasine spine surgery , though has come a long way, needs to provide technical solutions to minimize all the morbidity parameters involved in spine surgery, before it can replace most of the open spine surgeries, as in the case of laparoscopic surgery or arthroscopic surgery.

Iatrogenic Spinal Cord Injury Resulting From Cervical Spine Surgery

OpenAIRE

Daniels, Alan H.; Hart, Robert A.; Hilibrand, Alan S.; Fish, David E.; Wang, Jeffrey C.; Lord, Elizabeth L.; Buser, Zorica; Tortolani, P. Justin; Stroh, D. Alex; Nassr, Ahmad; Currier, Bradford L.; Sebastian, Arjun S.; Arnold, Paul M.; Fehlings, Michael G.; Mroz, Thomas E.

2017-01-01

Study Design: Retrospective cohort study of prospectively collected data. Objective: To examine the incidence of iatrogenic spinal cord injury following elective cervical spine surgery. Methods: A retrospective multicenter case series study involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network was conducted. Medical records for 17?625 patients who received cervical spine surgery (levels from C2 to C7) between January 1, 2005, and December 31, 2011,...

Slow-wave propagation and sheath interaction in the ion-cyclotron frequency range

International Nuclear Information System (INIS)

Myra, J R; D'Ippolito, D A

2010-01-01

In previous work (Myra J R and D'Ippolito D A 2008 Phys. Rev. Lett. 101 195004) we studied the propagation of slow-wave (SW) resonance cones launched parasitically by a fast-wave antenna into a tenuous magnetized plasma. Here we extend the treatment of SW propagation and sheath interaction to 'dense' scrape-off-layer plasmas where the usual cold-plasma SW is evanescent. Using the sheath boundary condition, it is shown that for sufficiently close limiters, the SW couples to a sheath-plasma wave and is no longer evanescent, but radially propagating. A self-consistent calculation of the rf-sheath width yields the resulting sheath voltage in terms of the amplitude of the launched SW, plasma parameters and connection length. The conditions for avoiding potentially deleterious rf-wall interactions in tokamak rf heating experiments are summarized.

Spine Trauma Associated with Off-Road Vehicles.

Science.gov (United States)

Reid, David C.; And Others

1988-01-01

A seven-year review of 1,447 cases of spine trauma showed that 53 cases were associated with the use of off-road vehicles, such as all-terrain vehicles, snowmobiles, and motorized dirt bikes. The development of safe riding areas, legislation governing safe operation, and public safety education are advised to curb this trend. (Author/JL)

Comparison of a fuel sheath failure model with published experimental data

International Nuclear Information System (INIS)

Varty, R.L.; Rosinger, H.E.

1982-01-01

A fuel sheath failure model has been compared with the published results of experiments in which a Zircaloy-4 fuel sheath was subjected to a temperature ramp and a differential pressure until failure occurred. The model assumes that the deformation of the sheath is controlled by steady-state creep and that there is a relationship between tangential stress and temperature at the instant of failure. The sheath failure model predictions agree reasonably well with the experimental data. The burst temperature is slightly overpredicted by the model. The burst strain is overpredicted for small experimental burst strains but is underpredicted otherwise. The reasons for these trends are discussed and the extremely wide variation in burst strain reported in the literature is explained using the model

Axial loaded MRI of the lumbar spine

Energy Technology Data Exchange (ETDEWEB)

Saifuddin, A. E-mail: asaifuddin@aol.com; Blease, S.; MacSweeney, E

2003-09-01

Magnetic resonance imaging is established as the technique of choice for assessment of degenerative disorders of the lumbar spine. However, it is routinely performed with the patient supine and the hips and knees flexed. The absence of axial loading and lumbar extension results in a maximization of spinal canal dimensions, which may in some cases, result in failure to demonstrate nerve root compression. Attempts have been made to image the lumbar spine in a more physiological state, either by imaging with flexion-extension, in the erect position or by using axial loading. This article reviews the literature relating to the above techniques.

Unusual Presentation of a Primary Ewing's Sarcoma of the Spine with Paraplegia: A Case Report.

Science.gov (United States)

Kannan, Karthik Kailash; Sundarapandian, Rajkumar Jayachandran; Surulivel, Vignesh Jayabalan

2015-03-01

Ewing's sarcoma is a primary malignancy of the bone affecting individuals in the second decade of life. Primary sarcomas of the spine are rare and the occurrence of Primary Ewing's sarcoma in the spine is very rare. Ewing's sarcoma occurring in the spine is divided into two types, Ewing's sarcoma of sacral spine which are very aggressive with poor prognosis and Ewing's sarcoma of the non sacral spine which is an extremely rare occurrence. Patient may present with neurological deficit when the tumour extends into the spinal canal causing spinal cord compression. Magnetic resonance imaging (MRI) is very sensitive in diagnosing the tumour and defining the extent of the tumour. Here we report an 18-year-old boy who presented with back pain and complete paraplegia of two months duration. The MRI gave a differential diagnosis of infective pathology due to the fluid collection in the paraspinal region, followed by primary malignancy as the second diagnosis. Patient underwent posterior spinal decompression and stabilization, and intaoperatively there was significant collection of pus whose culture showed no growth. The histopathology and immunohistochemistry studies confirmed the diagnosis of Ewing's sarcoma and patient was started on combination chemotherapy and radiotherapy.

The collisional capacitive RF sheath and the assumption of a sharp electron edge

Science.gov (United States)

Brinkmann, Ralf Peter

2008-10-01

The transition from quasi-neutrality to charge depletion is one of the characteristic features of the plasma boundary sheath. It is often described in terms of the so-called step model which assumes a transition point (electron step) where the electron density drops from a value equal to the ion density (in the bulk) to a value of zero (in the sheath). Inserted into Poisson's equation, the step model yields an expression for the field which is realistic deep in the sheath but fails to merge correctly into the ambipolar field of the bulk. This work studies the consequences of that approximation for the example of the collision-dominated, capacitive RF sheath by Lieberman [1]. First, the model is solved exactly, using a relaxation scheme. Then, the step approximation is applied which recovers Lieberman's semi-analytical solution. It is demonstrated that the step approximation induces a spurious divergence of the ion density at the sheath edge and prevents a matching of the sheath model to a bulk model. Integral sheath quantities, on the other hand, like the capacitance or the overall voltage drop, are faithfully reproduced. [1] M. A. Lieberman, IEEE Trans. Plasma Sci. 16, pp. 638-644 (1988).

Theoretical and computational studies of the sheath of a planar wall

Science.gov (United States)

Giraudo, Martina; Camporeale, Enrico; Delzanno, Gian Luca; Lapenta, Giovanni

2012-03-01

We present an investigation of the stability and nonlinear evolution of the sheath of a planar wall. We focus on the electrostatic limit. The stability analysis is conducted with a fluid model where continuity and momentum equations for the electrons and ions are coupled through Poisson's equation. The effect of electron emission from the wall is studied parametrically. Our results show that a sheath instability associated with the emitted electrons can exist. Following Ref. [1], it is interpreted as a Rayleigh-Taylor instability driven by the favorable combination of the sheath electron density gradient and electric field. Fully kinetic Particle-In-Cell (PIC) simulations will also be presented to investigate whether this instability indeed exists and to study the nonlinear effect of electron emission on the sheath profiles. The simulations will be conducted with CPIC, a new electrostatic PIC code that couples the standard PIC algorithm with strategies for generation and adaptation of the computational grid. [4pt] [1] G.L. Delzanno, ``A paradigm for the stability of the plasma sheath against fluid perturbations,'' Phys. Plasmas 18, 103508 (2011).

Dynamics of Dust in a Plasma Sheath with Magnetic Field

International Nuclear Information System (INIS)

Duan Ping; Liu Jinyuan; Gon Ye; Liu Yue; Wang Xiaogang

2007-01-01

Dynamics of dust in a plasma sheath with a magnetic field was investigated using a single particle model. The result shows that the radius, initial position, initial velocity of the dust particles and the magnetic field do effect their movement and equilibrium position in the plasma sheath. Generally, the dust particles with the same size, whatever original velocity and position they have, will locate at the same position in the end under the net actions of electrostatic, gravitational, neutral collisional, and Lorentz forces. But the dust particles will not locate in the plasma sheath if their radius is beyond a certain value

Over spinning a black hole?

Energy Technology Data Exchange (ETDEWEB)

Bouhmadi-Lopez, Mariam; Cardoso, Vitor; Nerozzi, Andrea; Rocha, Jorge V, E-mail: mariam.bouhmadi@ist.utl.pt, E-mail: vitor.cardoso@ist.utl.pt, E-mail: andrea.nerozzi@ist.utl.pt, E-mail: jorge.v.rocha@ist.utl.pt [CENTRA, Department de Fisica, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049 Lisboa (Portugal)

2011-09-22

A possible process to destroy a black hole consists on throwing point particles with sufficiently large angular momentum into the black hole. In the case of Kerr black holes, it was shown by Wald that particles with dangerously large angular momentum are simply not captured by the hole, and thus the event horizon is not destroyed. Here we reconsider this gedanken experiment for black holes in higher dimensions. We show that this particular way of destroying a black hole does not succeed and that Cosmic Censorship is preserved.

Coronal mass ejections and their sheath regions in interplanetary space

Science.gov (United States)

Kilpua, Emilia; Koskinen, Hannu E. J.; Pulkkinen, Tuija I.

2017-11-01

Interplanetary coronal mass ejections (ICMEs) are large-scale heliospheric transients that originate from the Sun. When an ICME is sufficiently faster than the preceding solar wind, a shock wave develops ahead of the ICME. The turbulent region between the shock and the ICME is called the sheath region. ICMEs and their sheaths and shocks are all interesting structures from the fundamental plasma physics viewpoint. They are also key drivers of space weather disturbances in the heliosphere and planetary environments. ICME-driven shock waves can accelerate charged particles to high energies. Sheaths and ICMEs drive practically all intense geospace storms at the Earth, and they can also affect dramatically the planetary radiation environments and atmospheres. This review focuses on the current understanding of observational signatures and properties of ICMEs and the associated sheath regions based on five decades of studies. In addition, we discuss modelling of ICMEs and many fundamental outstanding questions on their origin, evolution and effects, largely due to the limitations of single spacecraft observations of these macro-scale structures. We also present current understanding of space weather consequences of these large-scale solar wind structures, including effects at the other Solar System planets and exoplanets. We specially emphasize the different origin, properties and consequences of the sheaths and ICMEs.

Coronal mass ejections and their sheath regions in interplanetary space

Directory of Open Access Journals (Sweden)

Emilia Kilpua

2017-11-01

Full Text Available Abstract Interplanetary coronal mass ejections (ICMEs are large-scale heliospheric transients that originate from the Sun. When an ICME is sufficiently faster than the preceding solar wind, a shock wave develops ahead of the ICME. The turbulent region between the shock and the ICME is called the sheath region. ICMEs and their sheaths and shocks are all interesting structures from the fundamental plasma physics viewpoint. They are also key drivers of space weather disturbances in the heliosphere and planetary environments. ICME-driven shock waves can accelerate charged particles to high energies. Sheaths and ICMEs drive practically all intense geospace storms at the Earth, and they can also affect dramatically the planetary radiation environments and atmospheres. This review focuses on the current understanding of observational signatures and properties of ICMEs and the associated sheath regions based on five decades of studies. In addition, we discuss modelling of ICMEs and many fundamental outstanding questions on their origin, evolution and effects, largely due to the limitations of single spacecraft observations of these macro-scale structures. We also present current understanding of space weather consequences of these large-scale solar wind structures, including effects at the other Solar System planets and exoplanets. We specially emphasize the different origin, properties and consequences of the sheaths and ICMEs.

Extremal black holes in N=2 supergravity

NARCIS (Netherlands)

Katmadas, S.

2011-01-01

An explanation for the entropy of black holes has been an outstanding problem in recent decades. A special case where this is possible is that of extremal black holes in N=2 supergravity in four and five dimensions. The best developed case is for black holes preserving some supersymmetry (BPS),

Cervical spine injuries in suicidal hanging without a long-drop--patterns and possible underlying mechanisms of injury: an autopsy study.

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Nikolić, Slobodan; Zivković, Vladimir

2014-06-01

The incidence of cervical spine injuries in suicidal hangings with a short-drop has been reported to be extremely low or non-existent. The aim of this study was to determine the frequency and pattern of cervical spine injuries in suicidal hanging. A retrospective autopsy study was performed and short-drop suicidal hanging cases with documented cervical spine injuries were identified. This group was further analyzed with regard to the gender and age of the deceased, the position of the ligature knot, the presence of hyoid-laryngeal fractures, and the level of cervical spine injury. Cervical spine injuries were present in 25 of the 766 cases, with an average age of 71.9 ± 10.7 years (range 39-88 years). In 16 of these 25 cases, the ligature knot was in the anterior position. The most common pattern of cervical spine injury included partial or complete disruption of the anterior longitudinal ligament and widening of the lower cervical spine disk spaces, associated with absence of hyoid-laryngeal fractures. Cervical spine injuries are not commonly found in short-drop suicidal hanging, occurring in only 3.3 % of all observed cases. Cervical spine injury may be occurring in 80 % of subjects aged 66.5 years and above. The most common pattern of cervical spine injury included anterior longitudinal ligament disruption of the lower cervical spine, disk space widening, and no vertebral body displacement. These injuries were mainly associated with an anterior knot position, and may be a consequence of loop pressure to the posterior neck and cervical spine hyperextension.

Nonarteritic anterior ischemic optic neuropathy following pars plana vitrectomy for macular hole treatment: case report.

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Cunha, Leonardo Provetti; Cunha, Luciana Virgínia Ferreira Costa; Costa, Carolina Ferreira; Monteiro, Mário Luiz Ribeiro

2016-01-01

Herein, we report a case of nonarteritic anterior ischemic optic neuropathy (NAION) following uneventful pars plana vitrectomy for macular hole treatment. A 56-year-old previously healthy woman presented with a full-thickness macular hole in right eye (OD) and small cup-to-disc ratios in both eyes. Five days after surgery, she noticed sudden painless loss of vision in OD and was found to have an afferent pupillary defect and intraocular pressure of 29 mmHg. Fundus examination showed right optic disc edema and the resolution of a macular hole with an inferior altitudinal visual field defect. Erythrocyte sedimentation rate, C-reactive protein levels, and general physical examination findings were normal. She was treated with hypotensive eyedrops and oral prednisone, resulting in mild visual improvement and a pale optic disc. A combination of face-down position and increased intraocular pressure due to a small optic disc cup were considered as potential mechanisms underlying NAION in the present case. Vitreoretinal surgeons should be aware of NAION as a potentially serious complication and be able to recognize associated risk factors and clinical findings.

Interior structure of rotating black holes. III. Charged black holes

International Nuclear Information System (INIS)

Hamilton, Andrew J. S.

2011-01-01

This paper extends to the case of charged rotating black holes the conformally stationary, axisymmetric, conformally separable solutions presented for uncharged rotating black holes in a companion paper. In the present paper, the collisionless fluid accreted by the black hole may be charged. The charge of the black hole is determined self-consistently by the charge accretion rate. As in the uncharged case, hyper-relativistic counterstreaming between ingoing and outgoing streams drives inflation at (just above) the inner horizon, followed by collapse. If both ingoing and outgoing streams are charged, then conformal separability holds during early inflation, but fails as inflation develops. If conformal separability is imposed throughout inflation and collapse, then only one of the ingoing and outgoing streams can be charged: the other must be neutral. Conformal separability prescribes a hierarchy of boundary conditions on the ingoing and outgoing streams incident on the inner horizon. The dominant radial boundary conditions require that the incident ingoing and outgoing number densities be uniform with latitude, but the charge per particle must vary with latitude such that the incident charge densities vary in proportion to the radial electric field. The subdominant angular boundary conditions require specific forms of the incident number- and charge-weighted angular motions. If the streams fall freely from outside the horizon, then the prescribed angular conditions can be achieved by the charged stream, but not by the neutral stream. Thus, as in the case of an uncharged black hole, the neutral stream must be considered to be delivered ad hoc to just above the inner horizon.

Thoracic spine x-ray

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Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most ...

Halovest treatment in traumatic cervical spine injury.

Science.gov (United States)

Razak, M; Basir, T; Hyzan, Y; Johari, Z

1998-09-01

This is a cross-sectional study on the use of halovest appliance in the Orthopaedic and Traumatology Department, Kuala Lumpur Hospital from June 1993 to September 1996. Fifty-three patients with cervical spine injuries were treated by halovest stabilization. Majority of cases was caused by motor-vehicle accident; others were fall from height at construction sites, fall at home, hit by falling object and assault. The injuries were Jefferson fracture of C1, odontoid fractures, hangman fractures, open spinous process fracture and fracture body of C2, and fracture, and fracture-dislocation of the lower cervical spines. Majority of patients had hospital stay less than 30 days. The use of the halovest ranges from 4 to 16 weeks and the healing rate was 96%. Two patients of lower cervical spine injury had redislocation and one of them was operated. There was one case of non-union of type II odontoid fracture and treated by posterior fusion. Other complications encountered during halovest treatment were minor. They were pin-site infection, pin-loosening, clamp loosening and neck pain or neck stiffness. This method of treatment enables patient to ambulate early and reduces hospital stay. We found that halovest is easy to apply, safe and tolerable to most of the patients.

Anode Sheath Switching in a Carbon Nanotube Arc Plasma

International Nuclear Information System (INIS)

Fetterman, Abe; Raitses, Yevgeny; Keidar, Michael

2008-01-01

The anode ablation rate is investigated as a function of anode diameter for a carbon nanotube arc plasma. It is found that anomalously high ablation occurs for small anode diameters. This result is explained by the formation of a positive anode sheath. The increased ablation rate due to this positive anode sheath could imply greater production rate for carbon nanotubes.

A case of lung abscess successfully treated by transbronchial drainage using a guide sheath

OpenAIRE

Izumi, Hiroki; Kodani, Masahiro; Matsumoto, Shingo; Kawasaki, Yuji; Igishi, Tadashi; Shimizu, Eiji

2017-01-01

A 51?year?old man was diagnosed with colon cancer in September 2011, and a solitary pulmonary nodule was detected by computed tomography (CT) scan. We performed a transbronchial biopsy with endobronchial ultrasonography using a guide sheath (GS) and diagnosed lung metastasis of colon cancer. The patient experienced remittent fever after the biopsy in spite of intravenous antibiotic therapies. Moreover, his CT scan showed a large lung abscess at the biopsy site. We performed transbronchial dra...

Fatal outcome after brain stem infarction related to bilateral vertebral artery occlusion - case report of a detrimental complication of cervical spine trauma

Directory of Open Access Journals (Sweden)

Beauchamp Kathryn M

2011-07-01

Full Text Available Abstract Background Vertebral artery injury (VAI after blunt cervical trauma occurs more frequently than historically believed. The symptoms due to vertebral artery (VA occlusion usually manifest within the first 24 hours after trauma. Misdiagnosed VAI or delay in diagnosis has been reported to cause acute deterioration of previously conscious and neurologically intact patients. Case presentation A 67 year-old male was involved in a motor vehicle crash (MVC sustaining multiple injuries. Initial evaluation by the emergency medical response team revealed that he was alert, oriented, and neurologically intact. He was transferred to the local hospital where cervical spine computed tomography (CT revealed several abnormalities. Distraction and subluxation was present at C5-C6 and a comminuted fracture of the left lateral mass of C6 with violation of the transverse foramen was noted. Unavailability of a spine specialist prompted the patient's transfer to an area medical center equipped with spine care capabilities. After arrival, the patient became unresponsive and neurological deficits were noted. His continued deterioration prompted yet another transfer to our Level 1 regional trauma center. A repeat cervical spine CT at our institution revealed significantly worsened subluxation at C5-C6. CT angiogram also revealed complete occlusion of bilateral VA. The following day, a repeat CT of the head revealed brain stem infarction due to bilateral VA occlusion. Shortly following, the patient was diagnosed with brain death and care was withdrawn. Conclusion Brain stem infarction secondary to bilateral VA occlusion following cervical spine trauma resulted in fatal outcome. Prompt imaging evaluation is necessary to assess for VAI in cervical trauma cases with facet joint subluxation/dislocation or transverse foramen fracture so that treatment is not delayed. Additionally, multiple transportation events are risk factors for worsening when unstable cervical

The anatomy of the first sacral nerve root sheath shown by computed tomography.

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Moore, N R; Dixon, A K; Freer, C E

1989-08-01

Analysis of 25 patients with normal computed tomographic appearances at the lumbosacral junction revealed wide variation in the anatomical level at which the first sacral nerve root sheaths were seen emerging from the theca. In nine patients (36%), the S1 nerve root sheaths were first recognized at the level of the lumbosacral disc. In 14 patients (56%), the sheaths emerged cranial to the disc; it is possible that these patients may be more prone to neurological complications related to disc or facet joint disease, especially if the sheath is laterally sited within the lateral recess. Conversely, that minority of patients (two, 8%) in whom the root sheaths emerge caudal to the disc level may be relatively protected from neurological complications.

Ipsilateral Closed Clavicle and Scapular spine Fracture with Acromioclavicular Joint Disruption.

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Kembhavi, Raghavendra S; James, Boblee

2015-01-01

Injuries around shoulder and clavicle are quite common. Injuries involving lateral end of clavicle involving acromioclavicular joints are commoner injuries. In this rare injury, we report about a case involving clavicle and scapular spine fracture with acromioclavicular disruption which has never been described in English literature as per our knowledge. A patient with closed clavicle and scapular spine fracture with acromioclavicular joint disruption was treated with open reduction and internal fixation of clavicle and scapular spine as a staged procedures. Six months post operatively, patient had excellent functional recovery with near full range of movements. Though rare complex injury, clavicle fracture with scapular spine fracture with acromioclavicular disruption, when managed properly with good physiotherapy protocol post operatively will result in good clinical and functional outcome.

Effects of Reentry Plasma Sheath on GPS Patch Antenna Polarization Property

Directory of Open Access Journals (Sweden)

L. Zhao

2013-01-01

Full Text Available A plasma sheath enveloping a reentry vehicle would affect performances of on-board antenna greatly, especially the navigation antennas. This paper studies the effects of reentry plasma sheath on a GPS right-hand circularly polarized (RHCP patch antenna polarization property during a typical reentry process. Utilizing the algorithm of finite integration technique, the polarization characteristic of a GPS antenna coated by a plasma sheath is obtained. Results show that the GPS RHCP patch antenna radiation pattern distortions as well as polarization deteriorations exist during the entire reentry process, and the worst polarization mismatch loss between a GPS antenna and RHCP GPS signal is nearly 3 dB. This paper also indicates that measures should be taken to alleviate the plasma sheath for maintaining the GPS communication during the reentry process.

CASE SERIES: Malignant Peripheral Nerve Sheath Tumor in the Course of the Mandibular Nerve.

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Monika, Probst; Steffen, Koerdt; Maximilian, Ritschl Lucas; Oliver, Bissinger; Friederike, Liesche; Jens, Gempt; Bernhard, Meyer; Egon, Burian; Nina, Lummel; Andreas, Kolk

2018-06-05

Malignant peripheral nerve sheath tumors (MPNST) are infiltrating, aggressive tumors belonging to the group of soft tissue sarcomas. This report refers to three patients with a tumorous swelling in the entire inferior alveolar nerve (IAN) with similar disease courses suspect for a MPNST, which is particularly rare in the trigeminal nerve. Diagnostic tools, surgical proceedings and reconstructive procedures were highlighted. Three male patients (58-68 years), who suffered from numbness, pain and mild swelling in the sensation area served by the mental nerve presented at the department of oral and maxillofacial surgery and underwent diagnostic workup including CT, MRI, F18-PET-CT, as well as a biopsy of the clinical visible tumor mass with histopathological and molecular pathological analysis. MR imaging revealed the full extent of the tumor comprising the course of the entire mandibular nerve (one case bilateral) starting in the trigeminal ganglion through the IAN and ending in the mental foramen. Hence, both a neurosurgical and maxillofacial intervention with jaw replacement were necessary. Adjuvant radiation of the intracranial closed resection margins, and in one case of parts of the mandible was required. In order to reveal the full extent of tumor spread of MPNSTs sufficient preoperative imaging is crucial as it is an important step in therapy planning. MRI and PET-CT are the imaging modalities with the best prospect of success in depicting the whole extent of the disease. Radical surgical management is the treatment of choice whereas radiochemotherapy shows an ancillary part. Copyright © 2018 Elsevier Inc. All rights reserved.

Compressibility of rotating black holes

International Nuclear Information System (INIS)

Dolan, Brian P.

2011-01-01

Interpreting the cosmological constant as a pressure, whose thermodynamically conjugate variable is a volume, modifies the first law of black hole thermodynamics. Properties of the resulting thermodynamic volume are investigated: the compressibility and the speed of sound of the black hole are derived in the case of nonpositive cosmological constant. The adiabatic compressibility vanishes for a nonrotating black hole and is maximal in the extremal case--comparable with, but still less than, that of a cold neutron star. A speed of sound v s is associated with the adiabatic compressibility, which is equal to c for a nonrotating black hole and decreases as the angular momentum is increased. An extremal black hole has v s 2 =0.9 c 2 when the cosmological constant vanishes, and more generally v s is bounded below by c/√(2).

Internal pressure effects in the AIRCO-LCT conductor sheath

International Nuclear Information System (INIS)

Luton, J.N.; Clinard, J.A.; Lue, J.W.; Gray, W.H.; Summers, L.T.; Kershaw, R.

1985-01-01

The large Nb 3 Sn superconducting test coil produced by Westinghouse Electric Corporation for the international Large Coil Task (LCT) utilizes a conductor composed of cabled multifilamentary strands immersed in flowing supercritical helium contained by a square structural sheath made of the high-strength stainless alloy JBX-75. Peak pressures of a few hundred atmospheres are predicted to occur during quench, and measurement of these pressures seems feasible only through penetrations of the sheath wall. Fully processed short lengths of conductor were taken from production ends, fitted with pressure taps and strain gauges, and pressurized with helium gas. Failure, at 1000 atm at liquid nitrogen temperature, was by a catastrophic splitting of the sheath at a corner. Strain measurements and burst pressure agreed with elastic-plastic finite element stress calculations made for the sheath alone. Neither the production seam weld nor the pressure tap penetrations or their fillet welds contributed to the failure, although the finite element calculations show that these areas were also highly stressed, and examination of the failed sample showed that the finite welds were of poor quality. Failure was by tensile overload, with no evidence of fatigue

Magnetic resonance imaging of the spine in multiple myeloma

International Nuclear Information System (INIS)

Tanaka, Masato; Nakahara, Shinnosuke; Koura, Hiroshi; Kai, Nobuo; Asaumi, Koji; Tanaka, Shunsuke; Sezaki, Tatsuo; Fukuda, Shunichi; Sunami, Kazutaka

2000-01-01

The characteristics of diagnostic imaging of the spine in multiple myeloma were examined. Twenty-one patients with stage II-III multiple myeloma (male=12, female=9, mean age=64) underwent MRI of the spine. Other diagnostic imaging modalities used in these patients included, CT bone scintigraphy, and radiography. All images of the spine were assessed and compared with the MRI images. The type of progression was evaluated based on the tumor distribution classification established by Sezaki. T1-weighted images of all 21 patients showed low signals in vertebral bodies, including 14 cases with a focal low signal intensity and 7 cases with diffuse low signal intensity. On the T2-weighted images, 15 of the 21 cases (71%) showed equivalent signals, while T2*-weighted images obtained by the field-echo method yielded high signals in 10 out of 11 cases. It was difficult to differentiate between senile osteoporosis and multiple myeloma by MRI, but CT images clearly distinguished between them. The results suggested that fat-suppressive T1-contrast images and T2*-weighted images are useful in detecting lesions, especially focal low signal intensity lesions. Patients with the multiple-lesion-tumor type of disease were more likely to develop paralysis more than those with the diffuse myeloproliferative type. Thus, the tumor distribution classification established by Sezaki was useful in considering radiotherapy for the treatment of patients at risk of paralysis. Bone scintigraphy revealed accumulation only in spinal lesions caused by compression fractures, while CT appeared to be useful in localizing the diffuse myeloproliferative type of lesions. The problems associated with diagnosis by MRI are differentiation of multiple myeloma from senile osteoporosis and metastatic bone tumors of the spine. There are few specific findings in multiple myeloma. (K.H.)

Non-contiguous spinal injury in cervical spinal trauma: evaluation with cervical spine MRI

International Nuclear Information System (INIS)

Choi, Soo Jung; Shin, Myung Jin; Kim, Sung Moon; Bae, Sang Jin

2004-01-01

We wished to evaluate the incidence of non-contiguous spinal injury in the cervicothoracic junction (CTJ) or the upper thoracic spines on cervical spinal MR images in the patients with cervical spinal injuries. Seventy-five cervical spine MR imagings for acute cervical spinal injury were retrospectively reviewed (58 men and 17 women, mean age: 35.3, range: 18-81 years). They were divided into three groups based on the mechanism of injury; axial compression, hyperflexion or hyperextension injury, according to the findings on the MR and CT images. On cervical spine MR images, we evaluated the presence of non-contiguous spinal injury in the CTJ or upper thoracic spine with regard to the presence of marrow contusion or fracture, ligament injury, traumatic disc herniation and spinal cord injury. Twenty-one cases (28%) showed CTJ or upper thoracic spinal injuries (C7-T5) on cervical spinal MR images that were separated from the cervical spinal injuries. Seven of 21 cases revealed overt fractures in the CTJs or upper thoracic spines. Ligament injury in these regions was found in three cases. Traumatic disc herniation and spinal cord injury in these regions were shown in one and two cases, respectively. The incidence of the non-contiguous spinal injuries in CTJ or upper thoracic spines was higher in the axial compression injury group (35.5%) than in the hyperflexion injury group (26.9%) or the hyperextension (25%) injury group. However, there was no statistical significance (ρ > 0.05). Cervical spinal MR revealed non-contiguous CTJ or upper thoracic spinal injuries in 28% of the patients with cervical spinal injury. The mechanism of cervical spinal injury did not significantly affect the incidence of the non-contiguous CTJ or upper thoracic spinal injury

A Multicenter Review of Superior Laryngeal Nerve Injury Following Anterior Cervical Spine Surgery.

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Tempel, Zachary J; Smith, Justin S; Shaffrey, Christopher; Arnold, Paul M; Fehlings, Michael G; Mroz, Thomas E; Riew, K Daniel; Kanter, Adam S

2017-04-01

A retrospective multicenter case-series study; case report and review of the literature. The anatomy and function of the superior laryngeal nerve (SLN) are well described; however, the consequences of SLN injury remain variable and poorly defined. The prevalence of SLN injury as a consequence of cervical spine surgery is difficult to discern as its clinical manifestations are often inconstant and frequently of a subclinical degree. A multicenter study was performed to better delineate the risk factors, prevalence, and outcomes of SLN injury. A retrospective multicenter case-series study involving 21 high-volume surgical centers from the AO Spine North America Clinical Research Network. Medical records for 17 625 patients who received subaxial cervical spine surgery from 2005 to 2011 were reviewed to identify occurrence of 21 predefined treatment complications. Descriptive statistics were provided for baseline patient characteristics. A retrospective review of the neurosurgical literature on SLN injury was also performed. A total of 8887 patients who underwent anterior cervical spine surgery at the participating institutions were screened, and 1 case of SLN palsy was identified. The prevalence ranged from 0% to 1.25% across all centers. The patient identified underwent a C4 corpectomy. The SLN injury was identified after the patient demonstrated difficulty swallowing postoperatively. He underwent placement of a percutaneous gastrostomy tube and his SLN palsy resolved by 6 weeks. This multicenter study demonstrates that identification of SLN injury occurs very infrequently. Symptomatic SLN injury is an exceedingly rare complication of anterior cervical spine surgery. The SLN is particularly vulnerable when exposing the more rostral levels of the cervical spine. Careful dissection and retraction of the longus coli may decrease the risk of SLN injury during anterior cervical surgery.

Non-contiguous spinal injury in cervical spinal trauma: evaluation with cervical spine MRI

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Choi, Soo Jung; Shin, Myung Jin; Kim, Sung Moon [University of Ulsan College of Medicine, Seoul (Korea, Republic of); Bae, Sang Jin [Sanggyepaik Hospital, Inje University, Seoul (Korea, Republic of)

2004-12-15

We wished to evaluate the incidence of non-contiguous spinal injury in the cervicothoracic junction (CTJ) or the upper thoracic spines on cervical spinal MR images in the patients with cervical spinal injuries. Seventy-five cervical spine MR imagings for acute cervical spinal injury were retrospectively reviewed (58 men and 17 women, mean age: 35.3, range: 18-81 years). They were divided into three groups based on the mechanism of injury; axial compression, hyperflexion or hyperextension injury, according to the findings on the MR and CT images. On cervical spine MR images, we evaluated the presence of non-contiguous spinal injury in the CTJ or upper thoracic spine with regard to the presence of marrow contusion or fracture, ligament injury, traumatic disc herniation and spinal cord injury. Twenty-one cases (28%) showed CTJ or upper thoracic spinal injuries (C7-T5) on cervical spinal MR images that were separated from the cervical spinal injuries. Seven of 21 cases revealed overt fractures in the CTJs or upper thoracic spines. Ligament injury in these regions was found in three cases. Traumatic disc herniation and spinal cord injury in these regions were shown in one and two cases, respectively. The incidence of the non-contiguous spinal injuries in CTJ or upper thoracic spines was higher in the axial compression injury group (35.5%) than in the hyperflexion injury group (26.9%) or the hyperextension (25%) injury group. However, there was no statistical significance ({rho} > 0.05). Cervical spinal MR revealed non-contiguous CTJ or upper thoracic spinal injuries in 28% of the patients with cervical spinal injury. The mechanism of cervical spinal injury did not significantly affect the incidence of the non-contiguous CTJ or upper thoracic spinal injury.

Automated curved planar reformation of 3D spine images

International Nuclear Information System (INIS)

Vrtovec, Tomaz; Likar, Bostjan; Pernus, Franjo

2005-01-01

Traditional techniques for visualizing anatomical structures are based on planar cross-sections from volume images, such as images obtained by computed tomography (CT) or magnetic resonance imaging (MRI). However, planar cross-sections taken in the coordinate system of the 3D image often do not provide sufficient or qualitative enough diagnostic information, because planar cross-sections cannot follow curved anatomical structures (e.g. arteries, colon, spine, etc). Therefore, not all of the important details can be shown simultaneously in any planar cross-section. To overcome this problem, reformatted images in the coordinate system of the inspected structure must be created. This operation is usually referred to as curved planar reformation (CPR). In this paper we propose an automated method for CPR of 3D spine images, which is based on the image transformation from the standard image-based to a novel spine-based coordinate system. The axes of the proposed spine-based coordinate system are determined on the curve that represents the vertebral column, and the rotation of the vertebrae around the spine curve, both of which are described by polynomial models. The optimal polynomial parameters are obtained in an image analysis based optimization framework. The proposed method was qualitatively and quantitatively evaluated on five CT spine images. The method performed well on both normal and pathological cases and was consistent with manually obtained ground truth data. The proposed spine-based CPR benefits from reduced structural complexity in favour of improved feature perception of the spine. The reformatted images are diagnostically valuable and enable easier navigation, manipulation and orientation in 3D space. Moreover, reformatted images may prove useful for segmentation and other image analysis tasks

Black Hole Paradoxes

International Nuclear Information System (INIS)

Joshi, Pankaj S.; Narayan, Ramesh

2016-01-01

We propose here that the well-known black hole paradoxes such as the information loss and teleological nature of the event horizon are restricted to a particular idealized case, which is the homogeneous dust collapse model. In this case, the event horizon, which defines the boundary of the black hole, forms initially, and the singularity in the interior of the black hole at a later time. We show that, in contrast, gravitational collapse from physically more realistic initial conditions typically leads to the scenario in which the event horizon and space-time singularity form simultaneously. We point out that this apparently simple modification can mitigate the causality and teleological paradoxes, and also lends support to two recently suggested solutions to the information paradox, namely, the ‘firewall’ and ‘classical chaos’ proposals. (paper)

Hertwig’s Epithelial Root Sheath Fate during Initial Cellular Cementogenesis in Rat Molars

International Nuclear Information System (INIS)

Yamamoto, Tsuneyuki; Yamada, Tamaki; Yamamoto, Tomomaya; Hasegawa, Tomoka; Hongo, Hiromi; Oda, Kimimitsu; Amizuka, Norio

2015-01-01

To elucidate the fate of the epithelial root sheath during initial cellular cementogenesis, we examined developing maxillary first molars of rats by immunohistochemistry for keratin, vimentin, and tissue non-specific alkaline phosphatase (TNALP) and by TdT-mediated dUTP nick end labeling (TUNEL). The advancing root end was divided into three sections, which follow three distinct stages of initial cellular cementogenesis: section 1, where the epithelial sheath is intact; section 2, where the epithelial sheath becomes fragmented; and section 3, where initial cellular cementogenesis begins. After fragmentation of the epithelial sheath, many keratin-positive epithelial sheath cells were embedded in the rapidly growing cellular cementum. A few unembedded epithelial cells located on the cementum surface. Dental follicle cells, precementoblasts, and cementoblasts showed immunoreactivity for vimentin and TNALP. In all three sections, there were virtually no cells possessing double immunoreactivity for vimentin-keratin or TNALP-keratin and only embedded epithelial cells showed TUNEL reactivity. Taken together, these findings suggest that: (1) epithelial sheath cells divide into two groups; one group is embedded in the cementum and thereafter dies by apoptosis, and the other survives on the cementum surface as epithelial cell rests of Malassez; and (2) epithelial sheath cells do not undergo epithelial-mesenchymal transition during initial cellular cementogenesis

Treatment of hematomas after anterior cervical spine surgery: A retrospective study of 15 cases.

Science.gov (United States)

Miao, Weiliang; Ma, Xiaojun; Liang, Deyong; Sun, Yu

2018-05-04

Postoperative hematoma is a rare and dangerous complication of cervical spine surgery. The aim of this study was to investigate the incidence and related factors of postoperative hematoma, and to report on 15 cases at our institution over a 6-year period. Fifteen cases of postoperative hematoma were retrospectively identified. We investigated their neurological outcomes, characteristics, and surgical data, and identified risk factors associated with postoperative (PO) hematoma. Patients with hematoma were compared to those with no hematoma, in order to identify risk factors. Retropharyngeal hematomas developed in seven cases and epidural hematomas in eight. The total incidence of postoperative hematoma was 1.2%: 0.5% retropharyngeal hematomas and 0.6% spinal epidural hematomas. At time of onset, the severity of paralysis was assessed as grade B in one case, grade C in six cases, and grade D in eight cases. Risk factors for PO hematoma were: (1) presence of ossification of the posterior longitudinal ligament (OPLL) (Phematoma group and non-hematoma group (P>0.05). Precise preoperative preparation and systematic evaluation are central to successful management of PO hematoma after anterior cervical surgery. Risk factors for PO hematoma include multilevel decompression, OPLL, higher BMI, and longer operation time. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Epidural Hematoma Following Cervical Spine Surgery.

Science.gov (United States)

Schroeder, Gregory D; Hilibrand, Alan S; Arnold, Paul M; Fish, David E; Wang, Jeffrey C; Gum, Jeffrey L; Smith, Zachary A; Hsu, Wellington K; Gokaslan, Ziya L; Isaacs, Robert E; Kanter, Adam S; Mroz, Thomas E; Nassr, Ahmad; Sasso, Rick C; Fehlings, Michael G; Buser, Zorica; Bydon, Mohamad; Cha, Peter I; Chatterjee, Dhananjay; Gee, Erica L; Lord, Elizabeth L; Mayer, Erik N; McBride, Owen J; Nguyen, Emily C; Roe, Allison K; Tortolani, P Justin; Stroh, D Alex; Yanez, Marisa Y; Riew, K Daniel

2017-04-01

A multicentered retrospective case series. To determine the incidence and circumstances surrounding the development of a symptomatic postoperative epidural hematoma in the cervical spine. Patients who underwent cervical spine surgery between January 1, 2005, and December 31, 2011, at 23 institutions were reviewed, and all patients who developed an epidural hematoma were identified. A total of 16 582 cervical spine surgeries were identified, and 15 patients developed a postoperative epidural hematoma, for a total incidence of 0.090%. Substantial variation between institutions was noted, with 11 sites reporting no epidural hematomas, and 1 site reporting an incidence of 0.76%. All patients initially presented with a neurologic deficit. Nine patients had complete resolution of the neurologic deficit after hematoma evacuation; however 2 of the 3 patients (66%) who had a delay in the diagnosis of the epidural hematoma had residual neurologic deficits compared to only 4 of the 12 patients (33%) who had no delay in the diagnosis or treatment ( P = .53). Additionally, the patients who experienced a postoperative epidural hematoma did not experience any significant improvement in health-related quality-of-life metrics as a result of the index procedure at final follow-up evaluation. This is the largest series to date to analyze the incidence of an epidural hematoma following cervical spine surgery, and this study suggest that an epidural hematoma occurs in approximately 1 out of 1000 cervical spine surgeries. Prompt diagnosis and treatment may improve the chance of making a complete neurologic recovery, but patients who develop this complication do not show improvements in the health-related quality-of-life measurements.

A multi-national report on methods for institutional credentialing for spine radiosurgery

International Nuclear Information System (INIS)

Gerszten, Peter C; Shin, John H; Winey, Brian; Oh, Kevin; Sweeney, Reinhart A; Guckenberger, Matthias; Sahgal, Arjun; Sheehan, Jason P; Kersh, Ronald; Chen, Stephanie; Flickinger, John C; Quader, Mubina; Fahim, Daniel; Grills, Inga

2013-01-01

Stereotactic body radiotherapy and radiosurgery are rapidly emerging treatment options for both malignant and benign spine tumors. Proper institutional credentialing by physicians and medical physicists as well as other personnel is important for the safe and effective adoption of spine radiosurgery. This article describes the methods for institutional credentialing for spine radiosurgery at seven highly experienced international institutions. All institutions (n = 7) are members of the Elekta Spine Radiosurgery Research Consortium and have a dedicated research and clinical focus on image-guided spine radiosurgery. A questionnaire consisting of 24 items covering various aspects of institutional credentialing for spine radiosurgery was completed by all seven institutions. Close agreement was observed in most aspects of spine radiosurgery credentialing at each institution. A formal credentialing process was believed to be important for the implementation of a new spine radiosurgery program, for patient safety and clinical outcomes. One institution has a written policy specific for spine radiosurgery credentialing, but all have an undocumented credentialing system in place. All institutions rely upon an in-house proctoring system for the training of both physicians and medical physicists. Four institutions require physicians and medical physicists to attend corporate sponsored training. Two of these 4 institutions also require attendance at a non-corporate sponsored academic society radiosurgery course. Corporate as well as non-corporate sponsored training were believed to be complimentary and both important for training. In 5 centers, all cases must be reviewed at a multidisciplinary conference prior to radiosurgery treatment. At 3 centers, neurosurgeons are not required to be involved in all cases if there is no evidence for instability or spinal cord compression. Backup physicians and physicists are required at only 1 institution, but all institutions have more

Rigid Spine Syndrome among Children in Oman

Directory of Open Access Journals (Sweden)

Roshan Koul

2015-08-01

Full Text Available Objectives: Rigidity of the spine is common in adults but is rarely observed in children. The aim of this study was to report on rigid spine syndrome (RSS among children in Oman. Methods: Data on children diagnosed with RSS were collected consecutively at presentation between 1996 and 2014 at the Sultan Qaboos University Hospital (SQUH in Muscat, Oman. A diagnosis of RSS was based on the patient’s history, clinical examination, biochemical investigations, electrophysiological findings, neuro-imaging and muscle biopsy. Atrophy of the paraspinal muscles, particularly the erector spinae, was the diagnostic feature; this was noted using magnetic resonance imaging of the spine. Children with disease onset in the paraspinal muscles were labelled as having primary RSS or rigid spinal muscular dystrophy. Secondary RSS was classified as RSS due to the late involvement of other muscle diseases. Results: Over the 18-year period, 12 children were included in the study, with a maleto- female ratio of 9:3. A total of 10 children were found to have primary RSS or rigid spinal muscular dystrophy syndrome while two had secondary RSS. Onset of the disease ranged from birth to 18 months of age. A family history was noted, with two siblings from one family and three siblings from another (n = 5. On examination, children with primary RSS had typical features of severe spine rigidity at onset, with the rest of the neurological examination being normal. Conclusion: RSS is a rare disease with only 12 reported cases found at SQUH during the study period. Cases of primary RSS should be differentiated from the secondary type.

Primary Langerhans cell histiocytosis (LCH in the adult cervical spine: A case report and review of the literature

Directory of Open Access Journals (Sweden)

Sang-Deok Kim, M.D.

2017-03-01

Full Text Available Langerhans cell histiocytosis (LCH of the spine is a common benign disease in children and adolescents that rarely affects adults. Main management of single lesion (unifocal vertebral LCH is conservative method, unless there is neurological deficit due to mass effect, surgery must be considered. This is an interesting and rare case report of the patient with LCH at C5 vertebral body who underwent fusion surgery.

Unirradiated UO2 in irradiated zirconium alloy sheathing

International Nuclear Information System (INIS)

MacDonald, R.D.; Hardy, D.G.; Hunt, C.E.L.; Scoberg, J.A.

1979-07-01

Zircaloy-clad UO 2 fuel elements have defected in power reactors when element power outputs were raised significantly after a long irradiation at low power. We have irradiated fuel elements fabricated from fresh UO 2 pellets and zirconium alloy sheaths previously irradiated without fuel. This gave a fuel element with radiation-damaged low-ductility sheathing but with no fission products in the fuel. The elements were power boosted in-reactor to linear power outputs up to 84 kW/m for two five-day periods. No elements defected despite sheath strains of 0.82 percent at circumferential ridge postions. Half of these elements were subsequently soaked at low power to build up the fission product inventory in the fuel and then power boosted to 63 kW/m for a third time. Two elements defected on this final boost. We conclude that these defects were caused by fission product induced stress-corrosion cracking and that this mechanism plays an importent role in power reactor fuel defects. (auth)

Balloon sheaths for gastrointestinal guidance and access: a preliminary phantom study

International Nuclear Information System (INIS)

He, Xu; Shin, Ji Hoon; Kim, Hyo Cheol; Woo, Cheol Woong; Woo, Sung Ha; Choi, Won Chan; Kim, Jong Gyu; Lim, Jin Oh; Kim, Tae Hyung; Yoon, Chang Jin; Song, Ho Young; Kang, Wee Chang

2005-01-01

We wanted to evaluate the feasibility and usefulness of a newly designed balloon sheath for gastrointestinal guidance and access by conducting a phantom study. The newly designed balloon sheath consisted of an introducer sheath and a supporting balloon. A coil catheter was advanced over a guide wire into two gastroduodenal phantoms (one was with stricture and one was without stricture); group I was without a balloon sheath, group II was with a deflated balloon sheath, and groups III and IV were with an inflated balloon and with the balloon in the fundus and body, respectively. Each test was performed for 2 minutes and it was repeated 10 times in each group by two researchers, and the positions reached by the catheter tip were recorded. Both researchers had better performances with both phantoms in order of group IV, III, II and I. In group IV, both researchers advanced the catheter tip through the fourth duodenal segment in both the phantoms. In group I, however, the catheter tip never reached the third duodenal segment in both the phantoms by both the researchers. The numeric values for the four study groups were significantly different for both the phantoms (ρ < 0.001). A significant difference was also found between group III and IV for both phantoms (ρ < 0.001). The balloon sheath seems to be feasible for clinical use, and it has good clinical potential for gastrointestinal guidance and access, particularly when the inflated balloon is placed in the gastric body

Ontogeny of the sheathing leaf base in maize (Zea mays).

Science.gov (United States)

Johnston, Robyn; Leiboff, Samuel; Scanlon, Michael J

2015-01-01

Leaves develop from the shoot apical meristem (SAM) via recruitment of leaf founder cells. Unlike eudicots, most monocot leaves display parallel venation and sheathing bases wherein the margins overlap the stem. Here we utilized computed tomography (CT) imaging, localization of PIN-FORMED1 (PIN1) auxin transport proteins, and in situ hybridization of leaf developmental transcripts to analyze the ontogeny of monocot leaf morphology in maize (Zea mays). CT imaging of whole-mounted shoot apices illustrates the plastochron-specific stages during initiation of the basal sheath margins from the tubular disc of insertion (DOI). PIN1 localizations identify basipetal auxin transport in the SAM L1 layer at the site of leaf initiation, a process that continues reiteratively during later recruitment of lateral leaf domains. Refinement of these auxin transport domains results in multiple, parallel provascular strands within the initiating primordium. By contrast, auxin is transported from the L2 toward the L1 at the developing margins of the leaf sheath. Transcripts involved in organ boundary formation and dorsiventral patterning accumulate within the DOI, preceding the outgrowth of the overlapping margins of the sheathing leaf base. We suggest a model wherein sheathing bases and parallel veins are both patterned via the extended recruitment of lateral maize leaf domains from the SAM. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

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The Tubular Sheaths Encasing Methanosaeta and Methanospirillum Filaments are Functional Amyloids

DEFF Research Database (Denmark)

Dueholm, Morten Simonsen; Larsen, Poul; Nielsen, Per Halkjær

Archaea are well-recognized for their ability to thrive in extreme environments, although they can be found in virtually all habitats. Their adaptive success is linked to their unique cell envelopes, which often display extremely resistant to chemical and thermal denaturation and resist proteolysis...... techniques to show that the extracellular cell wall sheaths of the methanogenic archaea Methanosaeta and Methanospirillum are functional amyloid structures. Depolymerization of sheaths with formic acid and reducing agents and subsequent MS/MS analysis revealed that the sheaths are composed of a single major...... sheath protein (MspA). The amyloidogenic nature of MspA was confirmed by in vitro amyloid formation of recombinant MspA under a wide range of environmental conditions. This is the first report of a functional amyloid from the archaeal domain of life. The amyloid properties explain the extreme resistance...

Selective pH-Responsive Core-Sheath Nanofiber Membranes for Chem/Bio/Med Applications: Targeted Delivery of Functional Molecules.

Science.gov (United States)

Han, Daewoo; Steckl, Andrew J

2017-12-13

Core-sheath fibers using different Eudragit materials were successfully produced, and their controlled multi-pH responses have been demonstrated. Core-sheath fibers made of Eudragit L 100 (EL100) core and Eudragit S 100 (ES100) sheath provide protection and/or controlled release of core material at pH 6 by adjusting the sheath thickness (controlled by the flow rate of source polymer solution). The thickest sheath (∼250 nm) provides the least core release ∼1.25%/h, while the thinnest sheath (∼140 nm) provides much quicker release ∼16.75%/h. Furthermore, switching core and sheath material dramatically altered the pH response. Core-sheath fibers made of ES100 core and EL100 sheath can provide a consistent core release rate, while the sheath release rate becomes higher as the sheath layer becomes thinner. For example, the thinnest sheath (∼120 nm) provides a core and sheath release ratio of 1:2.5, while the thickest sheath (∼200 nm) shows only a ratio of 1:1.7. All core-sheath Eudragit fibers show no noticeable release at pH 5, while they are completely dissolved at pH 7. Extremely high surface area in the porous network of the fiber membranes provides much faster (>30 times) response to external pH changes as compared to that of equivalent cast films.

Primary malignant peripheral nerve sheath tumor at unusual location

Directory of Open Access Journals (Sweden)

Souvagya Panigrahi

2013-01-01

Full Text Available Malignant peripheral nerve sheath tumor (MPNST is a rare soft tissue sarcoma. Most arise in association with major nerve trunks. Their most common anatomical sites are the proximal portions of the upper and lower extremities and the trunk. MPNSTs have rarely been reported in literature to occur in other unusual body parts. We review all such cases reported till now in terms of site of origin, surgical treatment, adjuvant therapy and outcome and shortly describe our experience with two of these cases. Both of our case presented with lump at unusual sites resembling neurofibroma, one at orbitotemporal area and other in the paraspinal region with characteristic feature of neurofibroma with the exception that both had very short history of progression. They underwent gross total removal of the tumor with adjuvant radiotherapy postoperatively. At 6-month follow-up both are doing well with no evidence of recurrence.

The surgical management of the rheumatoid spine: Has the evolution of surgical intervention changed outcomes?

Directory of Open Access Journals (Sweden)

Robin Bhatia

2014-01-01

Full Text Available Context: Surgery for the rheumatoid cervical spine has been shown to stabilize the unstable spine; arrest/improve the progression of neurological deficit, help neck pain, and possibly decelerate the degenerative disease process. Operative intervention for the rheumatoid spine has significantly changed over the last 30 years. Aims: The purpose of this study was to review all cases of cervical rheumatoid spine requiring surgical intervention in a single unit over the last 30 years. Materials and Methods: A prospectively-maintained spine database was retrospectively searched for all cases of rheumatoid spine, leading to a review of indications, imaging, Ranawat and Myelopathy Disability Index measures, surgical morbidity, and survival curve analysis. Results: A total of 224 cases were identified between 1981 and 2011. Dividing the data into three time-epochs, there has been a significant increase in the ratio of segment-saving Goel-Harms C1-C2: Occipitocervical fixation (OCF surgery and survival has increased between 1981 and 2011 from 30% to 51%. Patients undergoing C1-C2 fixation were comparatively less myelopathic and in a better Ranawat class preoperatively, but postoperative outcome measures were well-preserved with favorable mortality rates over mean 39.6 months of follow-up. However, 11% of cases required OCF at mean 28 months post-C1-C2 fixation, largely due to instrumentation failure (80%. Conclusion: We present the largest series of surgically managed rheumatoid spines, revealing comparative data on OCF and C1-C2 fixation. Although survival has improved over the last 30 years, there have been changes in medical, surgical and perioperative management over that period of time too confounding the interpretation; however, the analysis presented suggests that rheumatoid patients presenting early in the disease process may benefit from C1 to C2 fixation, albeit with a proportion requiring OCF at a later time.

Postoperative 3D spine reconstruction by navigating partitioning manifolds

Energy Technology Data Exchange (ETDEWEB)

Kadoury, Samuel, E-mail: samuel.kadoury@polymtl.ca [Department of Computer and Software Engineering, Ecole Polytechnique Montreal, Montréal, Québec H3C 3A7 (Canada); Labelle, Hubert, E-mail: hubert.labelle@recherche-ste-justine.qc.ca; Parent, Stefan, E-mail: stefan.parent@umontreal.ca [CHU Sainte-Justine Hospital Research Center, Montréal, Québec H3T 1C5 (Canada)

2016-03-15

Purpose: The postoperative evaluation of scoliosis patients undergoing corrective treatment is an important task to assess the strategy of the spinal surgery. Using accurate 3D geometric models of the patient’s spine is essential to measure longitudinal changes in the patient’s anatomy. On the other hand, reconstructing the spine in 3D from postoperative radiographs is a challenging problem due to the presence of instrumentation (metallic rods and screws) occluding vertebrae on the spine. Methods: This paper describes the reconstruction problem by searching for the optimal model within a manifold space of articulated spines learned from a training dataset of pathological cases who underwent surgery. The manifold structure is implemented based on a multilevel manifold ensemble to structure the data, incorporating connections between nodes within a single manifold, in addition to connections between different multilevel manifolds, representing subregions with similar characteristics. Results: The reconstruction pipeline was evaluated on x-ray datasets from both preoperative patients and patients with spinal surgery. By comparing the method to ground-truth models, a 3D reconstruction accuracy of 2.24 ± 0.90 mm was obtained from 30 postoperative scoliotic patients, while handling patients with highly deformed spines. Conclusions: This paper illustrates how this manifold model can accurately identify similar spine models by navigating in the low-dimensional space, as well as computing nonlinear charts within local neighborhoods of the embedded space during the testing phase. This technique allows postoperative follow-ups of spinal surgery using personalized 3D spine models and assess surgical strategies for spinal deformities.

Postoperative 3D spine reconstruction by navigating partitioning manifolds

International Nuclear Information System (INIS)

Kadoury, Samuel; Labelle, Hubert; Parent, Stefan

2016-01-01

Purpose: The postoperative evaluation of scoliosis patients undergoing corrective treatment is an important task to assess the strategy of the spinal surgery. Using accurate 3D geometric models of the patient’s spine is essential to measure longitudinal changes in the patient’s anatomy. On the other hand, reconstructing the spine in 3D from postoperative radiographs is a challenging problem due to the presence of instrumentation (metallic rods and screws) occluding vertebrae on the spine. Methods: This paper describes the reconstruction problem by searching for the optimal model within a manifold space of articulated spines learned from a training dataset of pathological cases who underwent surgery. The manifold structure is implemented based on a multilevel manifold ensemble to structure the data, incorporating connections between nodes within a single manifold, in addition to connections between different multilevel manifolds, representing subregions with similar characteristics. Results: The reconstruction pipeline was evaluated on x-ray datasets from both preoperative patients and patients with spinal surgery. By comparing the method to ground-truth models, a 3D reconstruction accuracy of 2.24 ± 0.90 mm was obtained from 30 postoperative scoliotic patients, while handling patients with highly deformed spines. Conclusions: This paper illustrates how this manifold model can accurately identify similar spine models by navigating in the low-dimensional space, as well as computing nonlinear charts within local neighborhoods of the embedded space during the testing phase. This technique allows postoperative follow-ups of spinal surgery using personalized 3D spine models and assess surgical strategies for spinal deformities

Intraosseous hemangioblastoma of the cervical spine: case report.

Science.gov (United States)

Li, Zhenteng; Curtis, Brian; Layser, Robert; Selvarajan, Santosh Kumar; Harrop, James; Kenyon, Lawrence C; Parsons, Theodore; Rubin, Asa

2017-09-01

A 69-year-old woman presented with bilateral upper-extremity radiculopathy and neck pain after a mechanical fall. Admission CT and MRI of the cervical spine demonstrated a pathological C-4 fracture. Subsequent malignancy workup was negative. A CT-guided biopsy of the lesion showed intraosseous hemangioblastoma. Hemangioblastoma is a highly vascular, slow-growing tumor of the CNS; intraosseous location of this tumor is extremely rare. The authors review the diversity of its presentation and the treatment techniques of this rare tumor in an extremely rare location.

Can using a peel-away sheath in shunt implantation prevent ventricular catheter obstruction?

Science.gov (United States)

Camlar, Mahmut; Ersahin, Yusuf; Ozer, Fusun Demirçivi; Sen, Fatih; Orman, Mehmet

2011-02-01

Shunt obstruction is the most common shunt complication. In 2003, Kehler et al. used peel-away sheath while implanting the ventricular catheter in 20 patients. They found less revision rate in the peel-away sheath group. We aimed to test the efficacy of this technique in cadavers. We used 100 fresh brains obtained from medicolegal autopsies. Posterior parietal and frontal approaches were used to puncture the lateral ventricle in each cerebral hemisphere. The ventricle is punctured with a peel-away sheath system. After the ventricle is reached, the mandarin is retracted and the ventricular catheter is introduced through the opening. The ventricular catheter was removed from the ventricle, the opening at the tip of the ventricular catheter was checked out for obstruction, and the number of patent and plugged openings was recorded. This procedure was repeated four times for each location with and without using peel-away sheath. The control group consisted of the procedures done without using peel-away sheath. The number of the plugged openings in the peel-away sheath group was significantly smaller than the control group. There was no significant difference between the two groups in terms of gender and left and right cerebral hemispheres. The obstruction rate was significantly lower in the posterior parietal approach. Pearson's correlation showed that increasing age was associated with less obstruction rate. Peel-away sheath decreases the number of plugged openings of the ventricular catheter. A clinical cooperative study is needed to prove that a peel-away sheath should be included in the ventricular shunt systems in the market.

Defensive Medicine in U.S. Spine Neurosurgery.

Science.gov (United States)

Din, Ryan S; Yan, Sandra C; Cote, David J; Acosta, Michael A; Smith, Timothy R

2017-02-01

Observational cross-sectional survey. To compare defensive practices of U.S. spine and nonspine neurosurgeons in the context of state medical liability risk. Defensive medicine is a commonly reported and costly phenomenon in neurosurgery. Although state liability risk is thought to contribute greatly to defensive practice, variation within neurosurgical specialties has not been well explored. A validated, online survey was sent via email to 3344 members of the American Board of Neurological Surgeons. The instrument contained eight question domains: surgeon characteristics, patient characteristics, practice type, insurance type, surgeon liability profile, basic surgeon reimbursement, surgeon perceptions of medical legal environment, and the practice of defensive medicine. The overall response rate was 30.6% (n = 1026), including 499 neurosurgeons performing mainly spine procedures (48.6%). Spine neurosurgeons had a similar average practice duration as nonspine neurosurgeons (16.6 vs 16.9 years, P = 0.64) and comparable lifetime case volume (4767 vs 4,703, P = 0.71). The average annual malpractice premium for spine neurosurgeons was similar to nonspine neurosurgeons ($104,480.52 vs $101,721.76, P = 0.60). On average, spine neurosurgeons had a significantly higher rate of ordering labs, medications, referrals, procedures, and imaging solely for liability concerns compared with nonspine neurosurgeons (89.2% vs 84.6%, P = 0.031). Multivariate analysis revealed that spine neurosurgeons were roughly 3 times more likely to practice defensively compared with nonspine neurosurgeons (odds ratio, OR = 2.9, P = 0.001) when controlling for high-risk procedures (OR = 7.8, P < 0.001), annual malpractice premium (OR = 3.3, P = 0.01), percentage of patients publicly insured (OR = 1.1, P = 0.80), malpractice claims in the last 3 years (OR = 1.13, P = 0.71), and state medical-legal environment (OR = 1.3, P = 0

Oncogenous osteomalacia and myopericytoma of the thoracic spine: a case report.

Science.gov (United States)

Brunschweiler, Benoit; Guedj, Nathalie; Lenoir, Thibault; Faillot, Thierry; Rillardon, Ludovic; Guigui, Pierre

2009-11-01

A case report. To illustrate a rare case of oncogenous osteomalacia caused by a spinal thoracic myopericytoma. Osteomalacia related to a tumor is well known. The cause of the disorder is usually a highly vascularized, benign tumor of mesenchymal origin. Location of the tumor in the spine is very rare. Removal of the tumor is followed by resolution of osteomalacia. Diagnosis of oseomalacia was established on the presence of cardinal clinical, biologic, and radiologic features of osteomalacia. Localization of the tumor at T5 and T6 levels was obtained by magnetic resonance imaging. Surgical treatment consisted in a circumferential correction-fusion with hemivertebrectomy of T5 and T6 and tumor removal. Tumor removal was rapidly followed by disappearance of the clinical symptoms of osteomalacia, and by correction of hypophosphatemia. At 2-years follow-up, no recurrence of the tumor was detectable on imaging studies-the correction fusion remained stable. Histologically, the tumor was classified as a myopericytoma. There was no relapse of the clinical features of osteomalacia. However, secondary recurrence of the biologic markers due to an incomplete tumor removal was disclosed. Removal of the tumor was followed by healing of the clinical features of osteomalacia, demonstrating the causal connection between the myopericytoma and the osteopathy.

Slow Wave Propagation and Sheath Interaction for ICRF Waves in the Tokamak SOL

International Nuclear Information System (INIS)

Myra, J. R.; D'Ippolito, D. A.

2009-01-01

In previous work we studied the propagation of slow-wave resonance cones launched parasitically by a fast-wave antenna into a tenuous magnetized plasma. Here we extend the previous calculation to ''dense'' scrape-off-layer (SOL) plasmas where the usual slow wave is evanescent. Using the sheath boundary condition, it is shown that for sufficiently close limiters, the slow wave couples to a sheath plasma wave and is no longer evanescent, but radially propagating. A self-consistent calculation of the rf-sheath width yields the resulting sheath voltage in terms of the amplitude of the launched SW, plasma parameters and connection length.

Frictional effects between Overton sand and a simulated casing for a bore hole

International Nuclear Information System (INIS)

Dong, R.G.

1975-01-01

A series of tests were run to simulate the frictional effects between Overton sand and the casing for a bore hole for an underground nuclear test. The objective was to find a description for this frictional interaction which can be applied to an analysis of stemming materials under field conditions

Reliability and safety of a new upper cervical spine injury treatment algorithm

Directory of Open Access Journals (Sweden)

Andrei Fernandes Joaquim

Full Text Available ABSTRACT In the present study, we evaluated the reliability and safety of a new upper cervical spine injury treatment algorithm to help in the selection of the best treatment modality for these injuries. Methods Thirty cases, previously treated according to the new algorithm, were presented to four spine surgeons who were questioned about their personal suggestion for treatment, and the treatment suggested according to the application of the algorithm. After four weeks, the same questions were asked again to evaluate reliability (intra- and inter-observer using the Kappa index. Results The reliability of the treatment suggested by applying the algorithm was superior to the reliability of the surgeons’ personal suggestion for treatment. When applying the upper cervical spine injury treatment algorithm, an agreement with the treatment actually performed was obtained in more than 89% of the cases. Conclusion The system is safe and reliable for treating traumatic upper cervical spine injuries. The algorithm can be used to help surgeons in the decision between conservative versus surgical treatment of these injuries.

The relative axial expansions under irradiation of stacks of UO{sub 2} pellets in zircaloy sheaths

Energy Technology Data Exchange (ETDEWEB)

Notley, M. J.F.

1962-08-15

An experiment was performed to measure the relative axial movement of UO{sub 2} fuel pellets inside a Zircaloy sheath. Although the results must be treated with some reservation, the inferences are that there is very little relative movement between the fuel and the sheath when the two are in firm pressure contact. Relative movement was in the range 0.075 {+-} 0.03 cm for a 30 cm fuel length, and was not greatly affected by the power output, profile of the pellet end-faces or the diametral clearance left between the fuel and the sheath on assembly. However in two elements that had thick sheaths to withstand the coolant pressure and that were assembled with large diametral clearances (2% of the diameter) the available axial clearance for relative fuel/ sheath movement (1%) was fully taken up. The thin sheathed elements showed residual axial expansions of up to 0.17 cm, indicating that the pellets move relative to the sheath only until frictional forces are sufficient for the sheath to grip the fuel; thereafter the sheath is extended. The measurements also indicate that sheath elongation is governed by the temperature at the contact points between adjacent pellets, eg. at the inner edge of a pellet shoulder, as long as that temperature is below approximately 1000{sup o}C. At higher temperatures, the UO{sub 2} is too plastic to exert sufficient force to strain the sheath. (author)

The endomembrane sheath: a key structure for understanding the plant cell?

Science.gov (United States)

Reuzeau, C.; McNally, J. G.; Pickard, B. G.

1997-01-01

Recent evidence suggests that integrin is abundant in endomembranes of plant cells, and the endomembranes are clad by a sheath of cytoskeleton including F-actin. A role for endomembrane integrin and the endomembrane sheath is proposed: this system might orchestrate metabolic regulation by providing and modulating loci for channelling, and might accelerate channeling as needed by dragging the endoplasmic reticulum (ER) and organelles through the cytoplasm. To accomplish this "streaming", F-actin might lever against the rest of the endomembrane sheath and the ER might also lever against adhesion sites (i.e., plasmodesmata and plasmalemmal control centers). As an important agent in the control of cellular activities, according to this model, the endomembrane sheath would play a major part in responses to diverse signals and stresses, and under extreme stress cell survival would depend on the ability of the system to maintain enough integrity to direct critical syntheses and degradations.

Examination of Cervical Spine Histological Sections - A Technical Note

DEFF Research Database (Denmark)

Uhrenholt, Lars; Ullerup, Rita; Vesterby, Annie

2006-01-01

Detailed knowledge of the cervical spine facet joints morphology and anatomy is increasingly important since improved understanding of clinical syndromes, such as whiplash injuries, and therapeutic interventions is based on this knowledge. So far systematic examination of the age-related morphology...... of these joints has not yet been performed, nor has any generally accepted histological classification system for degenerative changes in the cervical spine facet joints been proposed. In the case of whiplash injuries the presented histological method has particular relevance since it allows detailed description...

Cervical spine instability in the course of rheumatoid arthritis – imaging methods

Directory of Open Access Journals (Sweden)

Małgorzata Mańczak

2017-08-01

Full Text Available Cervical spine is affected in more than a half of patients with rheumatoid arthritis (RA. Depending on the degree of damage to the individual joints and ligaments RA-related cervical spine instability takes the form of atlanto-axial subluxation, subaxial subluxation or cranial settling. In the advanced cases spinal stenosis can occur as well as spinal cord injuries with typical neurological symptoms. The identification of patients with cervical spine instability before the occurrence of neurological complications still constitutes a diagnostic challenge. The article presents the methods of cervical spine imaging with the use of plain radiographs, magnetic resonance imaging (MRI and computed tomography (CT. We discuss the advantages and disadvantages associated with each method and the possibility of its application in the diagnosis of cervical spine instability in RA. The knowledge of the above mentioned issues is indispensable to select an appropriate time for surgical intervention.

Microscopic origin of black hole reentrant phase transitions

Science.gov (United States)

Zangeneh, M. Kord; Dehyadegari, A.; Sheykhi, A.; Mann, R. B.

2018-04-01

Understanding the microscopic behavior of the black hole ingredients has been one of the important challenges in black hole physics during the past decades. In order to shed some light on the microscopic structure of black holes, in this paper, we explore a recently observed phenomenon for black holes namely reentrant phase transition, by employing the Ruppeiner geometry. Interestingly enough, we observe two properties for the phase behavior of small black holes that leads to reentrant phase transition. They are correlated and they are of the interaction type. For the range of pressure in which the system underlies reentrant phase transition, it transits from the large black holes phase to the small one which possesses higher correlation than the other ranges of pressures. On the other hand, the type of interaction between small black holes near the large/small transition line differs for usual and reentrant phase transitions. Indeed, for the usual case, the dominant interaction is repulsive whereas for the reentrant case we encounter an attractive interaction. We show that in the reentrant phase transition case, the small black holes behave like a bosonic gas whereas in the usual phase transition case, they behave like a quantum anyon gas.

Dust crystal in the electrode sheath of a gaseous discharge

International Nuclear Information System (INIS)

Schweigert, I.V.; Schweigert, V.A.

2002-01-01

The phenomena observed in strongly coupled dusty plasmas in the electrode sheath of gas discharge clearly indicate that the screened Coulomb potential is not valid for inter-particle interaction. The reason why the conventional model breaks down is clear now. The strong electric field, accelerating ions toward the cathode, leads to an asymmetrical particle shielding and the appearance of an attractive component in the inter-particle force. The sheath plasma with micro-particles is non Hamiltonian system because of input of energy from ion flux from the bulk plasma. The models of interaction potential of microparticles in sheath are proposed. The first is the linear effective positive charge (EPC). On the basis of this model the stability of the dust crystal in the sheath is analyzed both analytically and in MD simulations. The scenario of crystal melting is described. The role of different types of defects in the local heating of the crystal is considered. The next non-linear model of sheath plasma with micro-particles allows to find all parameter of plasma crystal: particle charge, inter-particle distance and study the structural transition. We constructed the analytical expression for inter-particle potential and have found the mechanism acceleration of extra particle beneath the monolayer. Recently new more simple analytical kinetic approach, accounting for ion collisions, have been developed. The structural transition in the dust molecular was obtained in simulation with multipole expansion model interaction potential

Thrombus Development on a Transseptal Sheath in the Right Atrium Before Electrical Pulmonary Vein Isolation

Directory of Open Access Journals (Sweden)

Nieves Romero-Rodriguez

2008-02-01

Full Text Available We describe the case of a patient who developed a thrombus on the transseptal sheath in the right atrium before transseptal puncture for circumferential pulmonary vein isolation for paroxysmal atrial fibrillation treatment. The use of intracardiac echocardiography allowed to its identification and probably prevented the patient from suffering a serious thromboembolic complication.

Dissociation and Re-Aggregation of Multicell-Ensheathed Fragments Responsible for Rapid Production of Massive Clumps of Leptothrix Sheaths

Science.gov (United States)

Kunoh, Tatsuki; Nagaoka, Noriyuki; McFarlane, Ian R.; Tamura, Katsunori; El-Naggar, Mohamed Y.; Kunoh, Hitoshi; Takada, Jun

2016-01-01

Species of the Fe/Mn-oxidizing bacteria Leptothrix produce tremendous amounts of microtubular, Fe/Mn-encrusted sheaths within a few days in outwells of groundwater that can rapidly clog water systems. To understand this mode of rapid sheath production and define the timescales involved, behaviors of sheath-forming Leptothrix sp. strain OUMS1 were examined using time-lapse video at the initial stage of sheath formation. OUMS1 formed clumps of tangled sheaths. Electron microscopy confirmed the presence of a thin layer of bacterial exopolymer fibrils around catenulate cells (corresponding to the immature sheath). In time-lapse videos, numerous sheath filaments that extended from the periphery of sheath clumps repeatedly fragmented at the apex of the same fragment, the fragments then aggregated and again elongated, eventually forming a large sheath clump comprising tangled sheaths within two days. In this study, we found that fast microscopic fragmentation, dissociation, re-aggregation and re-elongation events are the basis of the rapid, massive production of Leptothrix sheaths typically observed at macroscopic scales. PMID:27490579

Aspergillus Spondylitis involving the Cervico-Thoraco-Lumbar Spine in an Immunocompromised Patient: a Case Report

International Nuclear Information System (INIS)

Son, Jeong-Min; Jee, Won-Hee; Jung, Chan-Kwon; Kim, Sang-Il; Ha, Kee-Yong

2007-01-01

Aspergillosis is a rare cause of spondylitis. Moreover, early diagnosis by MR imaging and adequate treatment can prevent the serious complications of fungal infection. To our knowledge, the MR findings of multilevel aspergillus spondylitis in the cervico-thoraco-lumbar spine have not been previously described. Here, we report the MR findings of aspergillus spondylitis involving the cervical, thoracic, and lumbar spine in a liver transplant recipient. spergillosis is a rare cause of spondylitis, and early diagnosis by MR imaging and adequate treatment are essential for a good outcome. Although the MR findings of bacterial spondylitis have been fully described, the findings of aspergillus spondylitis have been rarely described, and to the best of our knowledge multilevel involvement of cervico-thoraco-lumbar spine has not been previously reported. Here, we report the MR imaging findings of aspergillus spondylitis involving the cervico-thoraco-lumbar spine in a liver transplant recipient. In conclusion, aspergillus spondylitis should be considered in the differential diagnosis of immunocompromised patients with MR findings resembling those of tuberculous spondylitis

Statistical mechanics of black holes

International Nuclear Information System (INIS)

Harms, B.; Leblanc, Y.

1992-01-01

We analyze the statistical mechanics of a gas of neutral and charged black holes. The microcanonical ensemble is the only possible approach to this system, and the equilibrium configuration is the one for which most of the energy is carried by a single black hole. Schwarzschild black holes are found to obey the statistical bootstrap condition. In all cases, the microcanonical temperature is identical to the Hawking temperature of the most massive black hole in the gas. U(1) charges in general break the bootstrap property. The problems of black-hole decay and of quantum coherence are also addressed

Floating fat in the wrist joint and in the tendon sheaths

Energy Technology Data Exchange (ETDEWEB)

Le Corroller, Thomas; Zink, Jean-Vincent; Champsaur, Pierre [Hopital Sainte-Marguerite, Radiology Department, Marseille (France); Parratte, Sebastien; Argenson, Jean-Noel [Hopital Sainte-Marguerite, Orthopaedic Surgery Department, Marseille (France)

2010-09-15

A traumatic fat effusion in a tendon sheath is an unreported entity. We report on the clinical and imaging features, including radiography and computed tomography (CT), of a fat-density effusion in the wrist joint and tendon sheaths of the extensor pollicis longus, extensor carpi radialis longus, and extensor carpi radialis brevis in a 28-year-old patient after a roller-skating accident. Radiographs showed a fracture of the distal radius and a wrist joint effusion. Preoperative CT examination exhibited two distinct layers resulting in a fat-fluid level pathognomonic of lipohemarthrosis in the radiocarpal joint. In addition, a fat-density effusion was noted in the sheaths of the second and third compartment extensor tendons. The lipohemarthrosis depicted on imaging classically results from the extrusion of fat from bone marrow into the joint space after an intraarticular fracture. Similarly, a traumatic fat effusion in a tendon sheath presents characteristic imaging features that may help to diagnose a potentially overlooked fracture. (orig.)

Floating fat in the wrist joint and in the tendon sheaths

International Nuclear Information System (INIS)

Le Corroller, Thomas; Zink, Jean-Vincent; Champsaur, Pierre; Parratte, Sebastien; Argenson, Jean-Noel

2010-01-01

A traumatic fat effusion in a tendon sheath is an unreported entity. We report on the clinical and imaging features, including radiography and computed tomography (CT), of a fat-density effusion in the wrist joint and tendon sheaths of the extensor pollicis longus, extensor carpi radialis longus, and extensor carpi radialis brevis in a 28-year-old patient after a roller-skating accident. Radiographs showed a fracture of the distal radius and a wrist joint effusion. Preoperative CT examination exhibited two distinct layers resulting in a fat-fluid level pathognomonic of lipohemarthrosis in the radiocarpal joint. In addition, a fat-density effusion was noted in the sheaths of the second and third compartment extensor tendons. The lipohemarthrosis depicted on imaging classically results from the extrusion of fat from bone marrow into the joint space after an intraarticular fracture. Similarly, a traumatic fat effusion in a tendon sheath presents characteristic imaging features that may help to diagnose a potentially overlooked fracture. (orig.)

Experimental Studies of Anode Sheath Phenomena in a Hall Thruster Discharge

International Nuclear Information System (INIS)

Dorf, L.; Raitses, Y.; Fisch, N.J.

2004-01-01

Both electron-repelling and electron-attracting anode sheaths in a Hall thruster were characterized by measuring the plasma potential with biased and emissive probes [L. Dorf, Y. Raitses, V. Semenov, and N.J. Fisch, Appl. Phys. Let. 84 (2004) 1070]. In the present work, two-dimensional structures of the plasma potential, electron temperature, and plasma density in the near-anode region of a Hall thruster with clean and dielectrically coated anodes are identified. Possible mechanisms of anode sheath formation in a Hall thruster are analyzed. The path for current closure to the anode appears to be the determining factor in the anode sheath formation process. The main conclusion of this work is that the anode sheath formation in Hall thrusters differs essentially from that in the other gas discharge devices, like a glow discharge or a hollow anode, because the Hall thruster utilizes long electron residence times to ionize rather than high neutral pressures

Reactive Arthritis Secondary to Cauda Equina Injury following Spine Fracture: A Case Report

Directory of Open Access Journals (Sweden)

Xiao Li

2011-01-01

Full Text Available A 38-year-old man presented with a one-month history of muscle weakness and dysesthesia in the lower extremities, urinary retention, and urinary tract infection after lumbar burst fracture resulted from high fall. During the rehabilitation in our hospital, he had arthritis in both the ankle and knee. However, the patient was treated as gouty arthropathy initially. The arthritis was completely remitted in a few days after the patient was diagnosed as reactive arthritis and started with sulfasalazine therapy and there was no recurrence during 4 months of follow-up. Based on this case, early recognition of reactive arthritis is of major importance to avoid delayed initiation of appropriate treatment in the patients with polyarthritis secondary to neurogenic bladder following cauda equina injury after spine fracture.

Electric fields in the sheath formed in a 300 mm, dual frequency capacitive argon discharge

International Nuclear Information System (INIS)

Barnat, E V; Miller, P A; Hebner, G A; Paterson, A M; Panagopoulos, T; Hammond, E; Holland, J

2007-01-01

The spatial structure and temporal evolution of the electric fields in a sheath formed in a dual frequency, 300 mm capacitive argon discharge are measured as functions of relative mixing between a low frequency current and a high frequency current. It is found that the overall structure of the sheath (potential across the sheath and the thickness of the sheath) are dominated by the lower frequency component while (smaller) oscillations in these quantities are dictated by the higher frequency component. Comparisons of the measured spatial and temporal profiles are made for Lieberman's and Robiche et al sheath model and with a particle in a cell calculation

30 CFR 15.32 - Tolerances for weight of explosive, sheath, wrapper, and specific gravity.

Science.gov (United States)

2010-07-01

..., wrapper, and specific gravity. 15.32 Section 15.32 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... explosive, sheath, wrapper, and specific gravity. (a) The weight of the explosive, the sheath, and the outer.... (c) The specific gravity of the explosive and sheath shall be within ±7.5 percent of that specified...

Effect of electron emission on an ion sheath structure

International Nuclear Information System (INIS)

Mishra, M K; Phukan, A; Chakraborty, M

2014-01-01

This article reports on the variations of ion sheath structures due to the emission of both hot and cold electrons in the target plasma region of a double plasma device. The ion sheath is produced in front of a negatively biased plate. The plasma is produced by hot filament discharge in the source region, and no discharge is created in the target region of the device. The plate is placed in the target (diffused plasma) region where cold electron emitting filaments are present. These cold electrons are free from maintenance of discharge, which is sustained in the source region. The hot ionizing electrons are present in the source region. Three important parameters are changed by both hot and cold electrons i.e. plasma density, plasma potential and electron temperature. The decrease in plasma potential and the increase in plasma density lead to the contraction of the sheath. (paper)

Malignant peripheral nerve sheath tumours in inherited disease

Directory of Open Access Journals (Sweden)

Evans D

2012-10-01

Full Text Available Abstract Background Malignant peripheral nerve sheath tumours (MPNST are rare tumours known to occur at high frequency in neurofibromatosis 1 (NF1, but may also occur in other cancer prone syndromes. Methods The North West Regional Genetic Register covers a population of 4.1 million and was interrogated for incidence of MPNST in 12 cancer prone syndromes. Age, incidence and survival curves were generated for NF1. Results Fifty two of 1254 NF1 patients developed MPNST, with MPNST also occurring in 2/181 cases of schwannomatosis and 2/895 NF2 patients. Three cases were also noted in TP53 mutation carriers. However, there were no cases amongst 5727BRCA1/2 carriers and first degree relatives, 2029 members from Lynch syndrome families, nor amongst 447 Familial Adenomatous Polyposis, 202 Gorlin syndrome, nor 87 vHL cases. Conclusion MPNST is associated with schwannomatosis and TP53 mutations and is confirmed at high frequency in NF1. It appears to be only increased in NF2 amongst those that have been irradiated. The lifetime risk of MPNST in NF1 is between 9–13%.

Accounting for Debye sheath expansion for proud Langmuir probes in magnetic confinement fusion plasmas.

Science.gov (United States)

Tsui, C K; Boedo, J A; Stangeby, P C

2018-01-01

A Child-Langmuir law-based method for accounting for Debye sheath expansion while fitting the current-voltage I-V characteristic of proud Langmuir probes (electrodes that extend into the volume of the plasma) is described. For Langmuir probes of a typical size used in tokamak plasmas, these new estimates of electron temperature and ion saturation current density values decreased by up to 60% compared to methods that did not account for sheath expansion. Changes to the collection area are modeled using the Child-Langmuir law and effective expansion perimeter l p , and the model is thus referred to as the "perimeter sheath expansion method." l p is determined solely from electrode geometry, so the method may be employed without prior measurement of the magnitude of the sheath expansion effects for a given Langmuir probe and can be used for electrodes of different geometries. This method correctly predicts the non-saturating ΔI/ΔV slope for cold, low-density plasmas where sheath-expansion effects are strong, as well as for hot plasmas where ΔI/ΔV ∼ 0, though it is shown that the sheath can still significantly affect the collection area in these hot conditions. The perimeter sheath expansion method has several advantages compared to methods where the non-saturating current is fitted: (1) It is more resilient to scatter in the I-V characteristics observed in turbulent plasmas. (2) It is able to separate the contributions to the ΔI/ΔV slope from sheath expansion to that of the high energy electron tail in high Te conditions. (3) It calculates the change in the collection area due to the Debye sheath for conditions where ΔI/ΔV ∼ 0 and for V = V f .

Soil sheaths, photosynthate distribution to roots, and rhizosphere water relations for Opuntia ficus-indica

Energy Technology Data Exchange (ETDEWEB)

Huang, B.; North, G.B.; Nobel, P.S. (Univ. of California, Los Angeles, CA (United States))

1993-09-01

Soil sheaths incorporating aggregated soil particles surround young roots of many species, but the effects of such sheaths on water movement between roots and the soil are largely unknown. The quantity and location of root exudates associated with soil sheath along the entire length of its young roots, except within 1.4 cm of the tip. The soil sheaths, which average 0.7 mm in thickness, were composed of soil particles and root hairs, both of which were covered with exuded mucilaginous material. As determined with a [sup 14]C pulse-labeling technique, 2% of newly fixed [sup 14]C-photosynthate was translocated into the roots at 3d, 6% at 9 d, and 8% at 15 d after labeling. The fraction of insoluble [sup 14]C in the roots increased twofold from 3 d to 15 d. Over the same time period, 6%-9% of the [sup 14]C translocated to the roots was exuded into the soil. The soluble [sup 14]C compounds exuded into the soil were greater in the 3-cm segment at the root tip than elsewhere along the root, whereas mucilage was exuded relatively uniformly along roots 15 cm in length. The volumetric efflux of water increase for both sheathed and unsheathed roots as the soil water potential decreased form -0.1 MPa to -1.0 MPa. The efflux rate was greater for unsheathed roots than for sheathed roots, which were more turgid and had a higher water potential, especially at lower soil water potentials. During drying, soil particles in the sheaths aggregate more tightly, making the sheaths less permeable to water and possibly creating air gaps. The soil sheaths of O. ficus-indica thus reduce water loss from the roots to a drying soil. 34 refs., 6 figs., 1 tab.

Malignant peripheral nerve sheath tumor arisen from plexiform Neurofibromatosis type 1

International Nuclear Information System (INIS)

Kirova, G.; Penkov, M.; Hadjidekov, G.; Parvanova, V.

2005-01-01

Neurofibromatosis type 1 is multisystemic neurocutaneous disorder involving both neuroectodermal and mesenchymal texture and the most common familial cancer predisposing syndrome in humans. Tumors occurring in patients with NF1 are primarily peripheral neurofibromas. They can continue to develop throughout life and the rate of appearance may vary greatly from year to year. At the same time any new and rapid change noted at clinical examination - increase volume, pain or neurological deficit, requires biopsy because of potential malignant transformation of the neurofibroma into neurofibrosarcoma. The definitive treatment depends on the respectable character of the tumor. In this case the authors document two cases of malignant peripheral nerve sheath tumor occurring in the association with NF type l

Utilization of manual therapy to the lumbar spine in conjunction with traditional conservative care for individuals with bilateral lower extremity complex regional pain syndrome: A case series.

Science.gov (United States)

Walston, Zachary; Hernandez, Luis; Yake, Dale

2018-06-06

Conservative therapies for complex regional pain syndrome (CRPS) have traditionally focused on exercise and desensitization techniques targeted at the involved extremity. The primary purpose of this case series is to report on the potential benefit of utilizing manual therapy to the lumbar spine in conjunction with traditional conservative care when treating patients with lower extremity CRPS. Two patients with the diagnosis of lower extremity CRPS were treated with manual therapy to the lumbar spine in conjunction with education, exercise, desensitization, and soft tissue techniques for the extremity. Patient 1 received 13 sessions over 6 weeks resulting in a 34-point improvement in oswestry disability index (ODI) and 35-point improvement in lower extremity functional scale (LEFS). Patient 2 received 21 sessions over 12 weeks resulting in a 28-point improvement in ODI and a 41-point improvement in LEFS. Both patients exhibited reductions in pain and clinically meaningful improvements in function. Manual therapies when applied to the lumbar spine in these patients as part of a comprehensive treatment plan resulted in improved spinal mobility, decreased pain, and reduction is distal referred symptoms. Although one cannot infer a cause and effect relationship from a case series, this report identifies meaningful clinical outcomes potentially associated with manual physical therapy to the lumbar spine for two patients with complex regional pain syndrome type 1.

Unusual Presentation of a Primary Ewing’s Sarcoma of the Spine with Paraplegia: A Case Report

Science.gov (United States)

Sundarapandian, Rajkumar Jayachandran; Surulivel, Vignesh Jayabalan

2015-01-01

Ewing’s sarcoma is a primary malignancy of the bone affecting individuals in the second decade of life. Primary sarcomas of the spine are rare and the occurrence of Primary Ewing’s sarcoma in the spine is very rare. Ewing’s sarcoma occurring in the spine is divided into two types, Ewing’s sarcoma of sacral spine which are very aggressive with poor prognosis and Ewing’s sarcoma of the non sacral spine which is an extremely rare occurrence. Patient may present with neurological deficit when the tumour extends into the spinal canal causing spinal cord compression. Magnetic resonance imaging (MRI) is very sensitive in diagnosing the tumour and defining the extent of the tumour. Here we report an 18-year-old boy who presented with back pain and complete paraplegia of two months duration. The MRI gave a differential diagnosis of infective pathology due to the fluid collection in the paraspinal region, followed by primary malignancy as the second diagnosis. Patient underwent posterior spinal decompression and stabilization, and intaoperatively there was significant collection of pus whose culture showed no growth. The histopathology and immunohistochemistry studies confirmed the diagnosis of Ewing’s sarcoma and patient was started on combination chemotherapy and radiotherapy. PMID:25954672

Robotics and the spine: a review of current and ongoing applications.

Science.gov (United States)

Shweikeh, Faris; Amadio, Jordan P; Arnell, Monica; Barnard, Zachary R; Kim, Terrence T; Johnson, J Patrick; Drazin, Doniel

2014-03-01

Robotics in the operating room has shown great use and versatility in multiple surgical fields. Robot-assisted spine surgery has gained significant favor over its relatively short existence, due to its intuitive promise of higher surgical accuracy and better outcomes with fewer complications. Here, the authors analyze the existing literature on this growing technology in the era of minimally invasive spine surgery. In an attempt to provide the most recent, up-to-date review of the current literature on robotic spine surgery, a search of the existing literature was conducted to obtain all relevant studies on robotics as it relates to its application in spine surgery and other interventions. In all, 45 articles were included in the analysis. The authors discuss the current status of this technology and its potential in multiple arenas of spinal interventions, mainly spine surgery and spine biomechanics testing. There are numerous potential advantages and limitations to robotic spine surgery, as suggested in published case reports and in retrospective and prospective studies. Randomized controlled trials are few in number and show conflicting results regarding accuracy. The present limitations may be surmountable with future technological improvements, greater surgeon experience, reduced cost, improved operating room dynamics, and more training of surgical team members. Given the promise of robotics for improvements in spine surgery and spine biomechanics testing, more studies are needed to further explore the applicability of this technology in the spinal operating room. Due to the significant cost of the robotic equipment, studies are needed to substantiate that the increased equipment costs will result in significant benefits that will justify the expense.

Disparities in Rates of Spine Surgery for Degenerative Spine Disease Between HIV Infected and Uninfected Veterans

Science.gov (United States)

King, Joseph T.; Gordon, Adam J.; Perkal, Melissa F.; Crystal, Stephen; Rosenthal, Ronnie A.; Rodriguez-Barradas, Maria C.; Butt, Adeel A.; Gibert, Cynthia L.; Rimland, David; Simberkoff, Michael S.; Justice, Amy C.

2011-01-01

Study Design Retrospective analysis of nationwide Veterans Health Administration (VA) clinical and administrative data. Objective Examine the association between HIV infection and the rate of spine surgery for degenerative spine disease. Summary of Background Data Combination anti-retroviral therapy (cART) has prolonged survival in patients with HIV/AIDS, increasing the prevalence of chronic conditions such as degenerative spine disease that may require spine surgery. Methods We studied all HIV infected patients under care in the VA from 1996–2008 (n=40,038) and uninfected comparator patients (n=79,039) matched on age, gender, race, year, and geographic region. The primary outcome was spine surgery for degenerative spine disease defined by ICD-9 procedure and diagnosis codes. We used a multivariate Poisson regression to model spine surgery rates by HIV infection status, adjusting for factors that might affect suitability for surgery (demographics, year, comorbidities, body mass index, cART, and laboratory values). Results Two-hundred twenty eight HIV infected and 784 uninfected patients underwent spine surgery for degenerative spine disease during 700,731 patient-years of follow-up (1.44 surgeries per 1,000 patient-years). The most common procedures were spinal decompression (50%), and decompression and fusion (33%); the most common surgical sites were the lumbosacral (50%), and cervical (40%) spine. Adjusted rates of surgery were lower for HIV infected patients (0.86 per 1,000 patient-years of follow-up) than for uninfected patients (1.41 per 1,000 patient-years; IRR 0.61, 95% CI: 0.51, 0.74, Pdegenerative spine disease. Possible explanations include disease prevalence, emphasis on treatment of non-spine HIV-related symptoms, surgical referral patterns, impact of HIV on surgery risk-benefit ratio, patient preferences, and surgeon bias. PMID:21697770

Photovoltaic building sheathing element with anti-slide features

Science.gov (United States)

Keenihan, James R.; Langmaid, Joseph A.; Lopez, Leonardo C.

2015-09-08

The present invention is premised` upon an assembly that includes at least a photovoltaic building sheathing element capable of being affixed on a building structure, the photovoltaic building sheathing element. The element including a photovoltaic cell assembly, a body portion attached to one or more portions of the photovoltaic cell assembly; and at feast a first and a second connector assembly capable of directly or indirectly electrically connecting the photovoltaic cell assembly to one or more adjoining devices; wherein the body portion includes one or more geometric features adapted to engage a vertically adjoining device before installation.

Time-lapse cased hole reservoir evaluation based on the dual-detector neutron lifetime log: the CHES II approach

International Nuclear Information System (INIS)

DeVries, M.R.; Fertl, W.

1977-01-01

A newly developed cased hole analysis technique provides detailed information on (1) reservoir rock properties, such as porosity, shaliness, and formation permeability, (2) reservoir fluid saturation, (3) distinction of oil and gas pays, (4) state of reservoir depletion, such as cumulative hydrocarbon-feet at present time and cumulative hydrocarbon-feet already depleted (e.g., the sum of both values then giving the cumulative hydrocarbon-feet originally present), and (5) monitoring of hydrocarbon/water and gas/oil contacts behind pipe. The basic well log data required for this type of analysis include the Dual-Detector Neutron Lifetime Log, run in casing at any particular time in the life of a reservoir, and the initial open-hole resistivity log. In addition, porosity information from open-hole porosity log(s) or core data is necessary. Field examples from several areas are presented and discussed in the light of formation reservoir and hydrocarbon production characteristics

Sheathed electrical resistance heaters for nuclear or other specialized service - approved 1973

International Nuclear Information System (INIS)

Anon.

1976-01-01

This specification presents the requirements for cylindrical metal-sheathed, electrical resistance heaters with compacted mineral-oxide insulation for nuclear or other specialized service. The intended use of a sheathed heater in a specific nuclear or general application will require an evaluation by the purchaser of the compatibility of the heater assembly in the proposed application including the effects of the integrated proposed application including the effects of the integrated neutron flux, temperature, and atmosphere on the properties of the materials of construction. This specification does not include all possible specifications, standards, etc. for materials that may be used in sheathing, insulation, resistance wire, or conductors wire in nuclear environments. The requirements of this specification include only the austenitic stainless steels and nickel-based alloys for sheathing; magnesium oxide, aluminum oxide, beryllium oxide for insulation; and nickel-chromium or iron-chromium-aluminum heater elements with or without low-resistance connecting wires. The intent of this specification is to present the requirements for heaters capable of operating at sheath temperatures and heat fluxes that will limit the maximum internal heater-element temperature to 1050 0 C

Dosimetric analysis of varying cord planning organ at risk volume in spine stereotactic body radiation therapy

Directory of Open Access Journals (Sweden)

Dawn Owen, MD, PhD

2016-01-01

Conclusion: Current guidelines may overestimate the risk of myelopathy from spine SBRT. The current study's population included both radiation-naïve and retreatment cases, but no myelopathy was observed despite exceeding recommended spine limits.

RF-sheath assessment of ICRF antenna geometry for long pulses

International Nuclear Information System (INIS)

Colas, L.; Bremond, S.

2003-01-01

Monitoring powered ion cyclotron resonance frequency (ICRF) antennas in magnetic fusion devices has revealed localized modifications of the plasma edge in the antenna shadow, most of them probably related to an enhanced polarization of the scrape-off layer (SOL) through radio-frequency (RF) sheath rectification. Although tolerable on present short RF pulses, sheaths should be minimized, as they may hinder proper operation of steady-state antennas and other subsystems connected magnetically to them, such as lower hybrid grills. As a first step towards mitigating RF sheaths in the design of future antennas, the present paper analyses the spatial structure of sheath potential maps in their vicinity, in relation with the 3D topology of RF near fields and the geometry of antenna front faces. Various combinations of poloidal radiating straps are first considered, and results are confronted to those inferred from transmission line theory. The dependence of sheath potentials on RF voltages or RF currents is studied. The role of RF near-field symmetries along tilted field lines is stressed to interpret such effects as that of strap phasing. A generalization of the 'dipole effect' is proposed. With similar arguments, the behavior of Faraday screen corners, where hot spots concentrate on Tore-Supra (TS), is then studied. The merits of aligning the antenna structure with the tilted magnetic field are thus discussed. The effect of switching from TS (high RF voltage near corners) to ITER-like electrical configurations of the straps (high voltage near equatorial plane) is also analyzed. (authors)

Levitation and dynamics of a collection of dust particles in a fully ionized plasma sheath

International Nuclear Information System (INIS)

Nitter, T.; Aslaksen, T.K.; Melandsoe, F.; Havnes, O.

1994-01-01

The authors have examined the dynamics of a collection of charged dust particles in the plasma sheath above a large body in a fully ionized space plasma when the radius of the large body is much larger than the sheath thickness. The dust particles are charged by the plasma, and the forces on the dust particles are assumed to be from the electric field in the sheath and from gravitation only. These forces will often act in opposite direction and may balance, making dust suspension and collection possible. The dust particles are supplied by injection or by electrostatic levitation. The ability of the sheath to collect dust particles, will be optimal for a certain combination of gravitation and plasma and dust particle parameters. In a dense dust sheath, the charges on the dust particles contribute significantly to the total space charge, and collective effects become important. These effects will reduce the magnitude of the sheath electric field strength and the charge on the dust particles. As dust particles are collected, the dust sheath is stretched and the largest dust particles may drop out, because the sheath is no longer able to suspend them. In a tenuous dust sheath, the inner layer, from the surface and about one Debye length thick, will be unstable for dust particle motion, and dust will not collect there. In a dense dust sheath, collective effects will decrease the thickness of this inner dust-free layer, making dust collection closer to the surface possible. By linearization of the force and current equations, they find the necessary and sufficient conditions which resemble those of planetary system bodies, but the results may also be of relevance to some laboratory plasmas

Benign Peripheral Nerve Sheath Tumor in a Wild Toco Toucan ( Ramphastos toco ).

Science.gov (United States)

Carvalho, Marcelo P N; Fernandes, Natalia C C A; Nemer, Viviane C; Neto, Ramiro N Dias; Teixeira, Rodrigo H F; Miranda, Bruna S; Mamprim, Maria J; Catão-Dias, José L; Réssio, Rodrigo A

2016-09-01

Peripheral nerve sheath tumors are a heterogeneous group of neoplasms that comprise neurofibromas, schwannomas, neurilemmomas, and perineuromas. In animals, peripheral nerve sheath neoplasms are most commonly diagnosed in dogs and cattle, followed by horses, goats, and cats, but their occurrence is uncommon in birds. An adult, free-living, male toco (common) toucan ( Ramphastos toco ) was admitted to the zoo animal clinic with weight loss, dehydration, and presence of a soft nodule adhered to the medial portion of the left pectoral muscle. Clinical, cytologic, and computed tomography scan results were indicative of a neoplasm. The toucan died during surgical resection of the mass. Necropsy, histopathologic, and immunohistochemical findings confirmed the diagnosis of benign peripheral nerve sheath tumor. To our knowledge, benign peripheral nerve sheath tumor has not previously been reported in a toucan or any other species in the order Piciformes.

Research articles published by Korean spine surgeons: Scientific progress and the increase in spine surgery.

Science.gov (United States)

Lee, Soo Eon; Jahng, Tae-Ahn; Kim, Ki-Jeong; Hyun, Seung-Jae; Kim, Hyun Jib; Kawaguchi, Yoshiharu

2017-02-01

There has been a marked increase in spine surgery in the 21st century, but there are no reports providing quantitative and qualitative analyses of research by Korean spine surgeons. The study goal was to assess the status of Korean spinal surgery and research. The number of spine surgeries was obtained from the Korean National Health Insurance Service. Research articles published by Korean spine surgeons were reviewed by using the Medline/PubMed online database. The number of spine surgeries in Korea increased markedly from 92,390 in 2004 to 164,291 in 2013. During the 2000-2014 period, 1982 articles were published by Korean spine surgeons. The annual number of articles increased from 20 articles in 2000 to 293 articles in 2014. There was a positive correlation between the annual spine surgery and article numbers (particles with Oxford levels of evidence 1, 2, and 3. The mean five-year impact factor (IF) for article quality was 1.79. There was no positive correlation between the annual IF and article numbers. Most articles (65.9%) were authored by neurosurgical spine surgeons. But spinal deformity-related topics were dominant among articles authored by orthopedics. The results show a clear quantitative increase in Korean spinal surgery and research over the last 15years. The lack of a correlation between annual IF and published article numbers indicate that Korean spine surgeons should endeavor to increase research value. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mid-range outcomes in 64 consecutive cases of multilevel fusion for degenerative diseases of the lumbar spine

Directory of Open Access Journals (Sweden)

Marc Röllinghoff

2010-01-01

Full Text Available In the treatment of multilevel degenerative disorders of the lumbar spine, spondylodesis plays a controversial role. Most patients can be treated conservatively with success. Multilevel lumbar fusion with instrumentation is associated with severe complications like failed back surgery syndrome, implant failure, and adjacent segment disease (ASD. This retrospective study examines the records of 70 elderly patients with degenerative changes or instability of the lumbar spine treated between 2002 and 2007 with spondylodesis of more than two segments. Sixty-four patients were included; 5 patients had died and one patient was lost to follow-up. We evaluated complications, clinical/radiological outcomes, and success of fusion. Flexion-extension and standing X-rays in two planes, MRI, and/or CT scans were obtained pre-operatively. Patients were assessed clinically using the Oswestry disability index (ODI and a Visual Analogue Scale (VAS. Surgery performed was dorsolateral fusion (46.9% or dorsal fusion with anterior lumbar interbody fusion (ALIF; 53.1%. Additional decompression was carried out in 37.5% of patients. Mean follow-up was 29.4±5.4 months. Average patient age was 64.7±4.3 years. Clinical outcomes were not satisfactory for all patients. VAS scores improved from 8.6±1.3 to 5.6±3.0 pre- to post-operatively, without statistical significance. ODI was also not significantly improved (56.1±22.3 pre- and 45.1±26.4 post-operatively. Successful fusion, defined as adequate bone mass with trabeculation at the facets and transverse processes or in the intervertebral segments, did not correlate with good clinical outcomes. Thirty-five of 64 patients (54% showed signs of pedicle screw loosening, especially of the screws at S1. However, only 7 of these 35 (20% complained of corresponding back pain. Revision surgery was required in 24 of 64 patients (38%. Of these, indications were adjacent segment disease (16 cases, pedicle screw loosening (7 cases

Statistical black-hole thermodynamics

International Nuclear Information System (INIS)

Bekenstein, J.D.

1975-01-01

Traditional methods from statistical thermodynamics, with appropriate modifications, are used to study several problems in black-hole thermodynamics. Jaynes's maximum-uncertainty method for computing probabilities is used to show that the earlier-formulated generalized second law is respected in statistically averaged form in the process of spontaneous radiation by a Kerr black hole discovered by Hawking, and also in the case of a Schwarzschild hole immersed in a bath of black-body radiation, however cold. The generalized second law is used to motivate a maximum-entropy principle for determining the equilibrium probability distribution for a system containing a black hole. As an application we derive the distribution for the radiation in equilibrium with a Kerr hole (it is found to agree with what would be expected from Hawking's results) and the form of the associated distribution among Kerr black-hole solution states of definite mass. The same results are shown to follow from a statistical interpretation of the concept of black-hole entropy as the natural logarithm of the number of possible interior configurations that are compatible with the given exterior black-hole state. We also formulate a Jaynes-type maximum-uncertainty principle for black holes, and apply it to obtain the probability distribution among Kerr solution states for an isolated radiating Kerr hole

Nonmetastatic Ewing’s Sarcoma of the Lumbar Spine in an Adult Patient

Directory of Open Access Journals (Sweden)

Maurizio Iacoangeli

2012-01-01

Full Text Available Although the spine is frequently involved in metastatic Ewing's sarcoma, primary involvement of the spine, beside sacrum, is much less frequent, especially in adult patients. Because of the low incidence of these tumors, there are currently no clinical guidelines outlining their management and a multitude of therapeutic strategies have been employed with varying success. The definitive management of Ewing's sarcoma of the spine, as in other locations, could include the combination of three main modalities: aggressive surgery, radiotherapy, and combined chemotherapy. Whenever possible, en bloc spondylectomy or extralesional resection is preferable, providing a better oncological result with a longer survival and a better preservation of the spine biomechanics. This is the lesson we learned about the case, we present here, of nonmetastatic lumbar localization by Ewing’s sarcoma in as adult patient.

Ultrasound-guided fine needle aspiration in the diagnosis of peripheral nerve sheath tumors in 4 dogs

Science.gov (United States)

da Costa, Ronaldo C.; Parent, Joane M.; Dobson, Howard; Ruotsalo, Kristiina; Holmberg, David; Duque, M. Carolina; Poma, Roberto

2008-01-01

Ultrasound-guided fine needle aspiration was used in establishing the diagnosis in 4 cases of malignant peripheral nerve sheath tumor. Sonographic and cytologic characteristics are discussed. Because of its availability and ease of use, axillary ultrasonography with fine needle aspiration can be an initial diagnostic step for suspected brachial plexus tumors. PMID:18320983

Design and Fabrication of a Precision Template for Spine Surgery Using Selective Laser Melting (SLM).

Science.gov (United States)

Wang, Di; Wang, Yimeng; Wang, Jianhua; Song, Changhui; Yang, Yongqiang; Zhang, Zimian; Lin, Hui; Zhen, Yongqiang; Liao, Suixiang

2016-07-22

In order to meet the clinical requirements of spine surgery, this paper proposes the fabrication of the customized template for spine surgery through computer-aided design. A 3D metal printing-selective laser melting (SLM) technique was employed to directly fabricate the 316L stainless steel template, and the metal template with tiny locating holes was used as an auxiliary tool to insert spinal screws inside the patient's body. To guarantee accurate fabrication of the template for cervical vertebra operation, the contact face was placed upwards to improve the joint quality between the template and the cervical vertebra. The joint surface of the printed template had a roughness of Ra = 13 ± 2 μm. After abrasive blasting, the surface roughness was Ra = 7 ± 0.5 μm. The surgical metal template was bound with the 3D-printed Acrylonitrile Butadiene Styrene (ABS) plastic model. The micro-hardness values determined at the cross-sections of SLM-processed samples varied from HV0.3 250 to HV0.3 280, and the measured tensile strength was in the range of 450 MPa to 560 MPa, which showed that the template had requisite strength. Finally, the metal template was clinically used in the patient's surgical operation, and the screws were inserted precisely as the result of using the auxiliary template. The geometrical parameters of the template hole (e.g., diameter and wall thickness) were optimized, and measures were taken to optimize the key geometrical units (e.g., hole units) in metal 3D printing. Compared to the traditional technology of screw insertion, the use of the surgical metal template enabled the screws to be inserted more easily and accurately during spinal surgery. However, the design of the high-quality template should fully take into account the clinical demands of surgeons, as well as the advice of the designing engineers and operating technicians.

Anode sheath transition in an anodic arc for synthesis of nanomaterials

Science.gov (United States)

Nemchinsky, V. A.; Raitses, Y.

2016-06-01

The arc discharge with ablating anode or so-called anodic arc is widely used for synthesis of nanomaterials, including carbon nanotubes and fullerens, metal nanoparticles etc. We present the model of this arc, which confirms the existence of the two different modes of the arc operation with two different anode sheath regimes, namely, with negative anode sheath and with positive anode sheath. It was previously suggested that these regimes are associated with two different anode ablating modes—low ablation mode with constant ablation rate and the enhanced ablation mode (Fetterman et al 2008 Carbon 46 1322). The transition of the arc operation from low ablation mode to high ablation mode is determined by the current density at the anode. The model can be used to self-consistently determine the distribution of the electric field, electron density and electron temperature in the near-anode region of the arc discharge. Simulations of the carbon arc predict that for low arc ablating modes, the current is driven mainly by the electron diffusion to the anode. For positive anode sheath, the anode voltage is close to the ionization potential of anode material, while for negative anode sheath, the anode voltage is an order of magnitude smaller. It is also shown that the near-anode plasma, is far from the ionization equilibrium.

Anode sheath transition in an anodic arc for synthesis of nanomaterials

International Nuclear Information System (INIS)

Nemchinsky, V A; Raitses, Y

2016-01-01

The arc discharge with ablating anode or so-called anodic arc is widely used for synthesis of nanomaterials, including carbon nanotubes and fullerens, metal nanoparticles etc. We present the model of this arc, which confirms the existence of the two different modes of the arc operation with two different anode sheath regimes, namely, with negative anode sheath and with positive anode sheath. It was previously suggested that these regimes are associated with two different anode ablating modes—low ablation mode with constant ablation rate and the enhanced ablation mode (Fetterman et al 2008 Carbon 46 1322). The transition of the arc operation from low ablation mode to high ablation mode is determined by the current density at the anode. The model can be used to self-consistently determine the distribution of the electric field, electron density and electron temperature in the near-anode region of the arc discharge. Simulations of the carbon arc predict that for low arc ablating modes, the current is driven mainly by the electron diffusion to the anode. For positive anode sheath, the anode voltage is close to the ionization potential of anode material, while for negative anode sheath, the anode voltage is an order of magnitude smaller. It is also shown that the near-anode plasma, is far from the ionization equilibrium. (paper)

The plasma-sheath boundary region

International Nuclear Information System (INIS)

Franklin, R N

2003-01-01

In this review an attempt is made to give a broad coverage of the problem of joining plasma and sheath over a wide range of physical conditions. We go back to the earliest works quoting them, where appropriate, to understand what those who introduced the various terms associated with the structure of the plasma-sheath had in mind. We try to bring out the essence of the insights that have been gained subsequently, by quoting from the literature selectively, indicating how misunderstandings have arisen. In order to make it accessible to the generality of those currently working in low temperature plasmas we have sought to avoid mathematical complexity but retain physical insight, quoting from published work where appropriate. Nevertheless, in clarifying my own ideas I have found it necessary to do additional original work in order to give a consistent picture. In this way I have sought to bring together work in the late 1920s, the 1960s, and now mindful of the commercial importance of plasma processing, work over the past 15 years that adds to the general understanding. (topical review)

Extension type fracture of the ankylotic thoracic spine with gross displacement causing esophageal rupture

NARCIS (Netherlands)

Groen, F. R J; Delawi, D.; Kruyt, M. C.; Oner, F. C.

2016-01-01

Purpose: This study aimed at discussing the relevance of the type B3 fracture of the new AOSpine classification. Methods: Hyperextension fractures of the spine are rare in the general population, but common in the ankylotic spine. We present a case of a severe spinal fracture with concomitant