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1

Herniated Lumbar Disc  

MedlinePLUS

... 50. A herniated lumbar disc may also cause back pain, although back pain alone (without leg pain) can have many causes ... 90% success); surgery is less effective in relieving back pain. Nonsurgical treatment Your doctor may prescribe nonsurgical treatments ...

2

Herniated Cervical Disc  

MedlinePLUS

... may be recommended if you have severe arm pain. These are injections of corticosteroid into the epidural space (the area ... muscles along the spine. While occasionally useful for pain control, trigger point injections do not help heal a herniated cervical disc. ...

3

[Spontaneous regression of symptomatic lumbar disc herniation].  

PubMed

Lumbar disc herniation is very common, sometimes leading to disability of the patient, and in a significant number of cases can only be solved with surgery. This paper reports a case with a large symptomatic disc herniation, which suffered spontaneous regression, and no surgery was necessary. The case is documented on serial MRI, consistent with the clinical improvement of the patient. PMID:22472931

Ribeiro, R Pimenta; Matos, R Milheiro; Vieira, A; Costa, J M; Proença, R; Pinto, R

2011-01-01

4

Spontaneous cervical intradural disc herniation.  

PubMed

Cervical intradural disc herniation (IDH) is a rare condition with very few case reports in the literature. We report a 64-year-old man who presented with sudden onset neck pain and rapidly progressing weakness in the left upper and lower limb. There was no history of trauma. MRI of the cervical spine showed a C6-C7 disc prolapse, for which he underwent a C6-C7 discectomy and fusion with bone graft through an anterior cervical approach. To our knowledge, all patients with a cervical IDH reported in the literature have a traumatic etiology. To the best of our knowledge, we report the first patient with a spontaneous cervical IDH. PMID:24210799

Warade, Abhijit G; Misra, Basant K

2014-05-01

5

Spinal Neurofibroma Masquerading as a Herniated Disc  

PubMed Central

We present the only case in English medical literature of a spinal neurofibroma misdiagnosed as a herniated disc using magnetic resonance imaging (MRI). This case presented with typical symptoms and radiological findings of a herniated disc. Intraoperatively, an abnormality was noted at the S1 nerve root sleeve. Further exploration revealed a spinal neurofibroma which was completely resected, resulting in an improvement in the patient’s symptoms. Currently, there is heavy reliance on MRI as a highly sensitive and specific tool used in the diagnosis of herniated lumbar discs. Although there have been occasional reports of misdiagnoses using MRI, there are no reported cases of a spinal neurofibroma being misdiagnosed as a herniated lumbar disc. Despite great advances in radiological diagnostic imaging, surgical surprises do still occur. Ultimately, instinct is still essential in intraoperative surgical decisions. PMID:23275853

Lamki, Tariq; Ammirati, Mario

2012-01-01

6

[Diagnostics and therapy of spinal disc herniation].  

PubMed

Degenerative processes in a movement segment of the vertebral column, which can potentially give rise to herniation of elements of the nucleus pulposus, are complex and of variable clinical and radiological dimensions; however the mere assumption that degenerative changes precede disc herniation remains a matter of debate. By definition, spinal disc herniation (SDH) refers to components of the gelatinous nucleus pulposus protruding beyond the dorsal level of the vertebral body margin through tears in the annulus fibrosus. Clinical presentation may include pain, paresis and sensory disturbances. Magnetic resonance imaging (MRI) is considered the gold standard in the diagnosis of SDH. In the majority of patients a conservative approach with physical therapy exercises and adequate analgesic and antiphlogistic medical treatment results in a substantial improvement of symptoms. PMID:25398570

Zimmer, A; Reith, W

2014-11-01

7

Paraplegia due to thoracic disc herniation.  

PubMed

Disc herniation at the thoracic the spine level is more common than generally thought. Localisation of pain may be vague and may erroneously point to cardiopulmonary, gastrointestinal, genito-urinary or even psychiatric disease. Magnetic resonance imaging is the investigation of choice, especially if spinal cord compression is suspected. PMID:9338030

Pal, B; Johnson, A

1997-07-01

8

Percutaneous treatment of intervertebral disc herniation.  

PubMed

Interventional radiology plays a major role in the management of symptomatic intervertebral disc herniations. In the absence of significant pain relief with conservative treatment including oral pain killers and anti-inflammatory drugs, selective image-guided periradicular infiltrations are generally indicated. The precise control of needle positioning allows optimal distribution of steroids along the painful nerve root. After 6 weeks of failure of conservative treatment including periradicular infiltration, treatment aiming to decompress or remove the herniation is considered. Conventional open surgery offers suboptimal results and is associated with significant morbidity. To achieve minimally invasive discal decompression, different percutaneous techniques have been developed. Their principle is to remove a small volume of nucleus, which results in an important reduction of intradiscal pressure and subsequently reduction of pressure inside the disc herniation. However, only contained disc herniations determined by computed tomography or magnetic resonance are indicated for these techniques. Thermal techniques such as radiofrequency or laser nucleotomy seem to be more effective than purely mechanical nucleotomy; indeed, they achieve discal decompression but also thermal destruction of intradiscal nociceptors, which may play a major role in the physiopathology of discal pain. The techniques of image-guided spinal periradicular infiltration and percutaneous nucleotomy with laser and radiofrequency are presented with emphasis on their best indications. PMID:21629404

Buy, Xavier; Gangi, Afshin

2010-06-01

9

Sacral perineural cyst accompanying disc herniation.  

PubMed

Although most of sacral perineural cysts are asymptomatic, some may produce symptoms. Specific radicular pain may be due to distortion, compression, or stretching of nerve root by a space occupying cyst. We report a rare case of S1 radiculopathy caused by sacral perineural cyst accompanying disc herniation. The patient underwent a microscopic discectomy at L5-S1 level. However, the patient's symptoms did not improved. The hypesthesia persisted, as did the right leg pain. Cyst-subarachnoid shunt was set to decompress nerve root and to equalize the cerebrospinal fluid pressure between the cephalad thecal sac and cyst. Immediately after surgery, the patient had no leg pain. After 6 months, the patient still remained free of leg pain. PMID:19352483

Ju, Chang Il; Shin, Ho; Kim, Seok Won; Kim, Hyeun Sung

2009-03-01

10

Thoracic Disc Herniation Presenting with Transient Anterior Spinal Artery Syndrome  

PubMed Central

Summary This report is a clinical and radiologic correlation of anterior spinal arterial distribution ischemia with a thoracic disc herniation affecting the artery of Adamkiewicz. We could only find one other similar reported case. A 38-year-old woman developed sudden onset of severe back pain and radiculopathy, followed by rapidly evolving paraparesis. The neurological examination was consistent with a deficit caused by anterior spinal artery ischemia. MRI revealed T2 signal change in the thoracolumbar spinal cord and a laterally placed, non-calcified disc herniation. Selective spinal angiography performed 30 hours after onset revealed displacement of the left T9 radicular feeding artery by the disc herniation; at this time the artery was patent. The patient experienced some resolution of symptoms within the first 24 hours and was managed conservatively and made a significant recovery within two weeks. Appropriately located thoracic disc herniations can disturb the blood supply to the thoracolumbar spinal cord. PMID:20667212

Guest, J.D.; Griesdale, D.E.; Marotta, T.

2000-01-01

11

Outcome of symptomatic upper lumbar disc herniation.  

PubMed

"Upper" lumbar disc herniations (LDH) are different from the "lower" and possess increased chance of neural compromise and cauda equina syndrome that necessitates operative management despite of contradictory surgical outcome. We underwent the study to assess the clinical and functional outcome of symptomatic upper LDH surgery from July 2003 to June 2012 in BSMMU, Dhaka, Bangladesh. The records of 123 patients (age range, 30-69 years), 56 men and 67 women (mean 52 years) having upper lumbar discectomy were reviewed. The surgical time, intra-operative blood loss, self evaluated back pain and thigh and/or groin pain status [using Visual Analogue Score (VAS)] and the disability status [using Oswestry disability (ODI) questionnaire] was analyzed. Radiological stability (using Posner's criteria), functional outcome [using Japanese Orthopaedic Association (JOA) Score] and overall outcome (using MacNab`s criteria), was calculated. Chi-squared test and z-test using SPSS revealed mean operative time and mean blood loss had no significant (p>0.05) difference. Pain, sensory, motor and reflex status as well as VAS, ODI and all the components of JOA questionnaire had significant (p<0.05) improvement. In spite of intra-operative complications in 20.32% cases, overall satisfactory outcome was achieved in 83.74% cases. The postoperative complications (08.13%) could be managed conservatively. However, carefully decided surgical alternatives resulted in satisfactory clinical and functional outcome in upper LDH surgery. PMID:25481595

Awwal, M A; Ahsan, M K; Sakeb, N

2014-10-01

12

Percutaneous Thoracic Intervertebral Disc Nucleoplasty: Technical Notes from 3 Patients with Painful Thoracic Disc Herniations  

PubMed Central

Symptomatic thoracic disc herniation is an uncommon condition and early surgical approaches were associated with significant morbidity and even mortality. We are the first to describe the technique of percutaneous thoracic nucleoplasty in three patients with severe radicular pain due to thoracic disc herniation. Two of the patients experienced more than 75% pain relief and one patient experienced more than 50% pain relief. Post-procedural pain relief was maintained up to an average of 10 months after nucleoplasty. One patient with preoperative neurological signs improved postoperatively. There were no reported complications in all three patients. In view of the reduced morbidity and shorter operating time, thoracic intervertebral disc nucleoplasty can be considered in patients with pain due to thoracic disc herniation, with no calcification of the herniated disc, and in patients who may be otherwise be unfit for conventional surgery. PMID:21386942

Gültuna, Ismail; Riezebos, Patricia; Beems, Tjemme; Vissers, Kris C.

2011-01-01

13

Treatment of lumbar disc herniation by percutaneous laser disc decompression (PLDD) and modified PLDD  

NASA Astrophysics Data System (ADS)

Objective: To study the micro-invasive operative method and to compare the effect of treatment of PLDD and modified PLDD for Lumbar Disc Herniation. Method: Vaporized part of the nucleus pulposus in single or multiple point after acupuncture into lumbar disc, to reach the purpose of the decompression of the lumbar disc. Result: Among the 19 cases of the regular PLDD group, the excellent and good rate was 63.2%, and among the 40 cases of the modified PLDD group, the excellent and good rate was 82.5%. Conclusion: The modified PLDD has good effect on the treatment for lumbar disc herniation.

Chi, Xiao fei; Li, Hong zhi; Wu, Ru zhou; Sui, Yun xian

2005-07-01

14

Automatic diagnosis of lumbar disc herniation with shape and appearance features from MRI  

NASA Astrophysics Data System (ADS)

Intervertebral disc herniation is a major reason for lower back pain (LBP), which is the second most common neurological ailment in the United States. Automation of herniated disc diagnosis reduces the large burden on radiologists who have to diagnose hundreds of cases each day using clinical MRI. We present a method for automatic diagnosis of lumbar disc herniation using appearance and shape features. We jointly use the intensity signal for modeling the appearance of herniated disc and the active shape model for modeling the shape of herniated disc. We utilize a Gibbs distribution for classification of discs using appearance and shape features. We use 33 clinical MRI cases of the lumbar area for training and testing both appearance and shape models. We achieve over 91% accuracy in detection of herniation in a cross-validation experiment with specificity of 91% and sensitivity of 94%.

Alomari, Raja'S.; Corso, Jason J.; Chaudhary, Vipin; Dhillon, Gurmeet

2010-03-01

15

Establishing the Effect of Vibration and Postural Constraint Loading on the Progression of Intervertebral Disc Herniation.  

E-print Network

??Intervertebral disc herniations have been indicated as a possible injury development pathway due to occupational vibration exposures in seated postures through epidemiological investigations. Little experimental… (more)

Yates, Justin

2009-01-01

16

THORACOLUMBAR INTRADURAL DISC HERNIATION IN EIGHT DOGS: CLINICAL, LOW-FIELD MAGNETIC RESONANCE IMAGING, AND COMPUTED TOMOGRAPHIC MYELOGRAPHY FINDINGS.  

PubMed

Intradural disc herniation is a rarely reported cause of neurologic deficits in dogs and few published studies have described comparative imaging characteristics. The purpose of this retrospective cross sectional study was to describe clinical and imaging findings in a group of dogs with confirmed thoracolumbar intradural disc herniation. Included dogs were referred to one of four clinics, had acute mono/paraparesis or paraplegia, had low field magnetic resonance imaging (MRI) and/or computed tomographic myelography, and were diagnosed with thoracolumbar intradural disc herniation during surgery. Eight dogs met inclusion criteria. The prevalence of thoracolumbar intradural disc herniation amongst the total population of dogs that developed a thoracolumbar intervertebral disc herniation and that were treated with a surgical procedure was 0.5%. Five dogs were examined using low-field MRI. Lesions that were suspected to be intervertebral disc herniations were observed; however, there were no specific findings indicating that the nucleus pulposus had penetrated into the subarachnoid space or into the spinal cord parenchyma. Thus, the dogs were misdiagnosed as having a conventional intervertebral disc herniation. An intradural extramedullary disc herniation (three cases) or intramedullary disc herniation (two cases) was confirmed during surgery. By using computed tomographic myelography (CTM) for the remaining three dogs, an intradural extramedullary mass surrounded by an accumulation of contrast medium was observed and confirmed during surgery. Findings from this small sample of eight dogs indicated that CTM may be more sensitive for diagnosing canine thoracolumbar intradural disc herniation than low-field MRI. PMID:25263808

Tamura, Shinji; Doi, Shoko; Tamura, Yumiko; Takahashi, Kuniaki; Enomoto, Hirokazu; Ozawa, Tsuyoshi; Uchida, Kazuyuki

2014-09-26

17

Hemilaminoplasty for the treatment of lumbar disc herniation  

PubMed Central

The aim of this study was to evaluate the clinical outcome of the hemilaminoplasty technique for the treatment of lumbar disc herniation (LDH). Forty-three cases of single-level LDH underwent a discectomy and hemilaminoplasty procedure. The preoperative JOA score and VAS of lower back and leg pain were 10.4±1.3, 7.8±2.1, and 8.6±1.7, respectively. The Cobb angle of lumbar sagittal alignment was 10.1±2.0. Twenty-five patients who agreed to lumbar discectomy through fenestration were enrolled as the control group. The postoperative JOA score and VAS of low back and leg pain of the hemilaminoplasty group were 19.4±1.3, 1.4±0.4, and 2.1±0.5, respectively. The Cobb angle was 29.2±1.9 degrees. There was no epidural scar observed in any of the patients. The Cobb angle of the hemilaminoplasty group was higher than that of the control group (p?

Xinyu, Liu; Jianmin, Li; Liangtai, Gong

2008-01-01

18

Magnetic resonance imaging of the lumbar herniated disc in pregnancy.  

PubMed

Lumbosacral pain is a significant complaint in approximately one-half of all pregnancies. In 15%, the pain can be disabling. Although the mechanical and positional stresses of pregnancy have been cited as the primary source of this discomfort, in approximately 1:10,000 cases a herniated lumbar disc (HNP) can be identified as the proximal cause of pain. A 35-yr-old G4AB3PO patient presenting at 10 wk of pregnancy with severe incapacitating lumbar radiculopathy is described. Magnetic resonance imaging, selected by the patient as a diagnostic option, demonstrated a clinically suspected large midline HNP at the L5-S1 level. In the past, visualizing the presence of a HNP during pregnancy by either computerized axial tomography scan or myelography has exposed the fetus to ionizing radiation. However, magnetic resonance imaging now permits a more detailed evaluation without similar x-ray exposure. To date, no recognized biologic effect of MRI on the developing fetus has been reported. Although the long-term effects of an magnetic resonance imaging on the developing fetus have not been conclusively evaluated, its potential for accurate diagnosis and subsequent patient management, as well as planning the delivery, appears to outweigh any recognized hazard to the developing fetus. PMID:7873115

LaBan, M M; Viola, S; Williams, D A; Wang, A M

1995-01-01

19

Co-occurrence of lumbar spondylolysis and lumbar disc herniation with lumbosacral nerve root anomaly  

PubMed Central

Lumbosacral nerve root anomalies are the leading cause of lumbar surgery failures. Although co-occurrence of lumbar spondylolysis and disc herniation is common, it is very rare to observe that a nerve root anomaly accompanies these lesions. A 49-year-old male patient presented with sudden-onset right leg pain. Examinations revealed L5/S1 lumbar spondylolysis and disc herniation. At preoperative period, he was also diagnosed with lumbosacral root anomaly. Following discectomy and root decompression, stabilization was performed. The complaints of the patient diagnosed with lumbosacral root anomaly at intraoperative period were improved at postoperative period. It should be remembered that in patients with lumbar disc herniation and spondylolysis, lumbar root anomalies may coexist when clinical and neurological picture is severe. Preoperative and perioperative assessments should be made meticulously to prevent neurological injury. PMID:25210343

Y?lmaz, Tevfik; Turan, Yahya; Gül?en, ?smail; Dalbayrak, Sedat

2014-01-01

20

Prevalence and Severity of Preoperative Disabilities in Iranian Patients with Lumbar Disc Herniation  

PubMed Central

Background: Literature recommends that refractory cases with lumbar disc herniation and appropriate indications are better to be treated surgically, but do all the patients throughout the world consent to the surgery with a same disability and pain threshold? We aim to elucidate the prevalence and severity of disabilities and pain in Iranian patients with lumbar disc herniation who have consented to the surgery. Methods: In this case series study, we clinically evaluated 194 (81 female and 113 male) admitted patients with primary, simple, and stable L4-L5 or L5-S1 lumbar disc herniation who were undergoing surgical discectomy. The mean age of the patients was 38.3±11.2 (range: 18-76 years old). Disabilities were evaluated by the items of the Oswestry Disability Index (ODI) questionnaire and severity of pain by the Visual Analogue Scale (VAS). Chi-square test was used to compare the qualitative variables. Results: Severe disability (39.2%) and crippled (29.9%) were the two most common types of disabilities. Mean ODI score was 56.7±21.1 (range: 16-92). Total mean VAS in all patients was 6.1±1.9 (range: 0-10). Sex and level of disc herniation had no statistical effect on preoperative ODI and VAS. The scale of six was the most frequent scale of preoperative VAS in our patients. Conclusion: Iranian patients with lumbar disc herniation who consented to surgery have relatively severe pain or disability. These severities in pain or disabilities have no correlation with sex or level of disc herniation and are not equal with developed countries. PMID:25207293

Omidi-Kashani, Farzad; Hasankhani, Ebrahim Ghayem; Moghadam, Mohammad Hallaj; Esfandiari, Mohammad Sadegh

2013-01-01

21

Lumbar Disc Herniation in a Patient With Congenital Vertebral Body Anomaly: A Case Report  

PubMed Central

Lumbar disc herniation is characterized with low back and leg pain resulting from the degenerated lumbar disc compressing the spinal nerve root. The etiology of degenerative spine is related to age, smoking, microtrauma, obesity, disorders of familial collagen structure, occupational and sports-related physical activity. However, disc herniations induced by congenital lumbar vertebral anomalies are rarely seen. Vertebral fusion defect is one of the causes of congenital anomalies. The pathogenesis of embryological corpus vertebral fusion anomaly is not fully known. In this paper, a 30-year-old patient who had the complaints of low back and right leg pain after falling from a height is presented. She had right L5-S1 disc herniation that had developed on the basis of S1 vertebra corpus fusion anomaly in Lumbar computed tomography. This case has been discussed in the light of literature based on evaluations of Lumbar Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). This case is unique in that it is the first case with development of lumbar disc herniation associated with S1 vertebral corpus fusion anomaly. Congenital malformations with unusual clinical presentation after trauma should be evaluated through advanced radiological imaging techniques. PMID:25620987

Atabey, Cem; Topuz, Ali Kivanc; Velio?lu, Murat; Demircan, Mehmet Nusret

2014-01-01

22

Lumbar disc herniation in a patient with congenital vertebral body anomaly: a case report.  

PubMed

Lumbar disc herniation is characterized with low back and leg pain resulting from the degenerated lumbar disc compressing the spinal nerve root. The etiology of degenerative spine is related to age, smoking, microtrauma, obesity, disorders of familial collagen structure, occupational and sports-related physical activity. However, disc herniations induced by congenital lumbar vertebral anomalies are rarely seen. Vertebral fusion defect is one of the causes of congenital anomalies. The pathogenesis of embryological corpus vertebral fusion anomaly is not fully known. In this paper, a 30-year-old patient who had the complaints of low back and right leg pain after falling from a height is presented. She had right L5-S1 disc herniation that had developed on the basis of S1 vertebra corpus fusion anomaly in Lumbar computed tomography. This case has been discussed in the light of literature based on evaluations of Lumbar Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). This case is unique in that it is the first case with development of lumbar disc herniation associated with S1 vertebral corpus fusion anomaly. Congenital malformations with unusual clinical presentation after trauma should be evaluated through advanced radiological imaging techniques. PMID:25620987

Atabey, Cem; Ero?lu, Ahmet; Topuz, Ali Kivanc; Velio?lu, Murat; Demircan, Mehmet Nusret

2014-12-01

23

Five and Ten Year Follow-up on Intradiscal Ozone Injection for Disc Herniation  

PubMed Central

Background Disc herniation is the most common cause for spinal surgery and many clinicians employ epidural steroid injections with limited success. Intradiscal injection of ozone gas has been used as an alternative to epidural steroids and surgical discectomy. Early results are positive but long-term data are limited. Methods One hundred and eight patients with confirmed contiguous disc herniation were treated with intradiscal injection of ozone in 2002-2003. One-hundred seven patients were available for telephone follow-up at 5 years. Sixty patients were available for a similar telephone follow-up at ten years. Patients were asked to describe their clinical outcome since the injection. Surgical events were documented. MRI images were reviewed to assess the reduction in disc herniation at six months. Results MRI films demonstrated a consistent reduction in the size of the disc herniation. Seventy-nine percent of patients had a reduction in herniation volume and the average reduction was 56%. There were 19 patients that ultimately had surgery and 12 of them occurred in the first six months after injection. One of these 12 was due to surgery at another level. Two surgeries involved an interspinous spacer indicated by stenosis or DDD. All other surgeries were discectomies. Of the patients that avoided surgery 82% were improved at 5 years and 88% were improved at 10 years. Other than subsequent surgeries, no spine-related complications were experienced. Conclusions/Level of Evidence We conclude that ozone is safe and effective in approximately 75% of patients with disc herniation and the benefit is maintained through ten years. This is a retrospective review and randomized trials are needed. Clinical Relevance Intradiscal ozone injection may enable patients to address their pain without multiple epidural injections and surgery. The benefit of ozone is durable and does not preclude future surgical options. The risk reward profile for this treatment is favorable. PMID:25694935

Buric, Josip; Rigobello, Luca; Hooper, David

2014-01-01

24

Plasma disc decompression for contained cervical disc herniation: a randomized, controlled trial  

PubMed Central

Prospective case series studies have shown that plasma disc decompression (PDD) using the COBLATION SpineWand device (ArthroCare Corporation, Austin, TX) is effective for decompressing the disc nucleus in symptomatic contained cervical disc herniations. This prospective, randomized controlled clinical trial was conducted to evaluate the clinical outcomes of percutaneous PDD as compared to conservative care (CC) through 1 year. Patients (n = 115) had neck/arm pain >50 on the visual analog scale (VAS) pain scale and had failed at least 30 days of failed CC. Patients were randomly assigned to receive either PDD (n = 62) or CC (n = 58). Clinical outcome was determined by VAS pain score, neck disability index (NDI) score, and SF-36 health survey, collected at 6 weeks, 3 months, 6 months, and 1 year. The PDD group had significantly lower VAS pain scores at all follow-up time points (PDD vs. CC: 6 weeks, ?46.87 ± 2.71 vs. ?15.26 ± 1.97; 3 months, ?53.16 ± 2.74 vs. ?30.45 ± 2.59; 6 months, ?56.22 ± 2.63 vs. ?40.26 ± 2.56; 1 year, ?65.73 ± 2.24 vs. ?36.45 ± 2.86; GEE, P < 0.0001). PDD patients also had significant NDI score improvement over baseline when compared to CC patients at the 6 weeks (PDD vs. CC: ?9.15 ± 1.06 vs. ?4.61 ± 0.53, P < 0.0001) and 1 year (PDD vs. CC: ?16.70 ± 0.29 vs. ?12.40 ± 1.26, P = 0.005) follow-ups. PDD patients showed statistically significant improvement over baseline in SF-36 physical component summary scores when compared to CC patients at 6 weeks and 1 year (PDD vs. CC: 8.86 + 8.04 vs. 4.24 ± 3.79, P = 0.0004; 17.64 ± 10.37 vs. 10.50 ± 10.6, P = 0.0003, respectively). In patients who had neck/arm pain due to a contained cervical disc herniation, PDD was associated with significantly better clinical outcomes than a CC regimen. At 1 year, CC patients appeared to suffer a “relapse, showing signs of decline in most measurements, whereas PDD patients showed continued stable improvement. PMID:19902277

Nardi, Pier Vittorio

2009-01-01

25

Is there any relationship between proinflammatory mediator levels in disc material and myelopathy with cervical disc herniation and spondylosis? A non-randomized, prospective clinical study  

PubMed Central

The proinflammatory mediator (PIM) levels were assessed in surgically removed samples of herniated cervical intervertebral discs. The objective of this study was to investigate if there is a correlation between the levels of PIMs in disc material and myelopathy associated with cervical intervertebral disc herniation and spondylosis. The role of proinflammatory mediators in the degeneration of intervertebral disc and the inflammatory effects of disc herniations on radicular pain has been previously published. However, the possible relationship between PIMs and myelopathy related to cervical disc herniation and spondylosis has not been investigated before. Thirty-two patients undergoing surgery for cervical disc herniation and spondylosis were investigated. Surgically obtained disc materials, stored at 70°C, were classified into two groups: cervical disc herniation alone or with myelopathy. Biochemical preparation and solid phase enzyme amplified sensitivity immunoassay (ELISIA) analysis of the samples were performed to assess the concentration of mediators in the samples. Very similar values of interleukin-6 were found in both groups whereas the concentrations of mediators were significantly higher in myelopathy group. This study has demonstrated that PIMs are involved in cervical intervertebral disc degeneration with higher concentrations in the samples associated with myelopathy. PMID:17476536

Asir, Alparslan; Cetinkal, Ahmet; Gedik, Nursal; Kutlay, Ahmet Murat; Çolak, Ahmet; Kurtar, Sedat; Simsek, Hakan

2007-01-01

26

Spontaneous intradural disc herniation with focal distension of the subarachnoid space in a dog.  

PubMed

Myelo-computed tomography of a paraparetic 14-year-old dog revealed subarachnoid distension with an intradural filling defect above the T13-L1 disc space. T12-L1 hemilaminectomy followed by durotomy allowed removal of a large piece of degenerated disc material that compressed the spinal parenchyma. Full return to function was achieved 10 days post-surgery. The distension was likely secondary to the intradural herniation, and is a rare and distinct finding. PMID:23633713

Barnoon, Itai; Chai, Orit; Srugo, Itai; Peeri, Dana; Konstantin, Lilach; Brenner, Ori; Shamir, Merav H

2012-11-01

27

Diagnosis of Disc Herniation Based on Classifiers and Features Generated from Spine MR Images  

E-print Network

Diagnosis of Disc Herniation Based on Classifiers and Features Generated from Spine MR Images patients suffer from lumbar disorders and radiologists have to treat more patients reliably in a limited of diagnostic radiologists.3 Accordingly, the demand for computer-assisted image processing and analysis has

Chaudhary, Vipin

28

Clinical Features and Surgical Results of Cervical Myelopathy Caused by Soft Disc Herniation  

PubMed Central

Objective There are many causes of cervical myelopathy including trauma, degenerative conditions, tumors and demyelinating disorders. However, myelopathy caused by soft disc herniation might be seen rarely than the spondylosis caused by hard disc. Here, authors retrospectively analyzed the clinical features and results of cervical myelopathy caused by soft disc herniation. Methods From March 2010 to December 2010, 134 patients with degenerative cervical spinal disease were treated with anterior cervical discectomy and interbody fusion. Among them, 21 patients with cervical myelopathy secondary to cervical soft disc herniation were analyzed. Their clinical features, preoperative and, postoperative clinical results were evaluated by Nurick Grade and Japanese Orthopaedic Association scale (JOA) retrospectively. Preoperative clinical features including duration of myelopathy, pain intensity and postoperative clinical results including improvement rate of myelopathy and radiculopathy were retrospectively analyzed by Nurick Grade and JOA scale. We also evaluated correlation between the duration of symptom, type of the disc herniation, pain intensity and clinical outcome. Results Mean age was 49.7 and male was predominant. Gait disturbance with mild to moderate pain was most common symptom in clinical features. Severe pain was shown in only 9 cases, and the other 12 cases experienced mild to moderate pain. Mean duration of myelopathy was 1.18 month. The mean JOA scores were 11.22 before surgery and 14.2 after surgery. The mean Nurick grades were 2.78 before treatment and 1.67 after treatment. Neurologic status of mild or moderate pain group on preoperative state is worse than that of severe pain group. The patients with duration of myelopathy symptom (<1 month) showed lower clinical improvement rate than the patients with myelopathy over 1 month. Patients with median type of disc herniation showed poorer neurological status than those with paramedian type of herniation in preoperative state. Conclusion Authors reviewed the clinical features and surgical outcome of the cervical myelopathy secondary to cervical soft disc herniation. We presumed that patients of more than one month of symptom duration, mild to moderate initial symptom would be related with better postoperative improvement rate. PMID:24757475

Park, Sung Joo; Kim, Min Ki; Lee, Sung Ho; Oh, In Ho

2013-01-01

29

Chiropractic Management and Rehabilitation of a 38-Year-Old Male with an L5-S1 Disc Herniation  

PubMed Central

Abstract Objective To present a chiropractic treatment plan for a patient with lumbar disc herniation including radicular symptoms below the knee. Clinical Features A 38-year-old male experienced lumbar disc herniation with radicular symptoms to the lower extremities, below the knee. Etiology of this episode included a traumatic injury which was complicated by chronic degenerative joint and disc changes. Intervention and Outcome The treatment regime included chiropractic spinal manipulation, modalities and exercise rehabilitation. Specific rehabilitation exercises were used during various stages of healing in an attempt to stabilize a potential surgical case. Goals of care were to alleviate pain, increase function, and decrease peripheralization related to disc herniation in this case. The patient reached a level of functional biomechanical stability over 15 weeks. Conclusion This case demonstrates that with proper management, rehabilitation of a patient with disc herniation can be reached in a short duration of time. PMID:19674637

Hammer, Christopher J.

2004-01-01

30

Spontaneous Cervical Intradural Disc Herniation Associated with Ossification of Posterior Longitudinal Ligament  

PubMed Central

Intradural herniation of a cervical disc is rare; less than 35 cases have been reported to date. A 52-year-old man with preexisting ossification of posterior longitudinal ligament developed severe neck pain with Lt hemiparesis while asleep. Neurological exam was consistent with Brown-Séquard syndrome. Magnetic resonance images showed a C5-6 herniated disc that was adjacent to the ossified ligament and indenting the cord. The mass was surrounded by cerebrospinal fluid signal intensity margin, and caudally the ventral dura line appears divided into two, consistent with the “Y-sign” described by Sasaji et al. Cord edema were noted. Because of preexisting canal stenosis and spinal cord at risk, a laminoplasty was performed, followed by an anterior C6 corpectomy. Spot-weld type adhesions of the posterior longitudinal ligament to the dura was noted, along with a longitudinal tear in the dura. An intradural extra-arachnoid fragment of herniated disc was removed. Clinical exam at 6 months after surgery revealed normal muscle strength but persistent mild paresthesias. It is difficult to make a definite diagnosis of intradural herniation preoperatively; however, the clinical findings and radiographic signs mentioned above are suggestive and should alert the surgeon to look for an intradural fragment. PMID:25295205

Wang, Dachuan; Wang, Haifeng; Shen, Wun-Jer

2014-01-01

31

Nucleus pulposus cells derived IGF-1 and MCP-1 enhance osteoclastogenesis and vertebrae disruption in lumbar disc herniation  

PubMed Central

Study design: Chronic strained lumbar disc herniation (LDH) cases were classified into bulging LDH, herniated LDH and prolapse LDH types according to imaging examination, and vertebrae disruptions were evaluated. Cytokines derived from the nucleus pulposus cells were detected, and their effects on osteoclastogenesis, as well as the mechanisms involved, were studied via an in vitro osteoclast differentiation system. Objective: To clarify the mechanisms of lumbar vertebrae resorption induced by lumbar herniation. Summary and background data: Chronic strained lumbar disc herniation induced vertebrae erosion exacerbates quality of patients’ life and clinical outcome. Although nucleus pulposus cells derived cytokines were reported to play an important role in this pathogenesis, the fundamental mechanisms underlying this process are still unclear. Methods: Chronic strained lumbar disc herniation patients were diagnosed with CT scan and T2-weighted magnetic resonance imaging. RNA was extracted from 192 surgical specimens of the herniated lumbar disc and 29 surgical excisions of the lumbar disc from spinal injury patients. The expressions of osteoclastogenesis related cytokines and chemokines were examined using real time PCR. Monocytes were induced into osteoclast with M-CSF and RANKL in vitro, while the IGF-1 and MCP-1 were added into the differentiation procedure in order to evaluate the effects and explore the molecular mechanisms. Results: Vertebrae erosion had a positive relationship with lumbar disc herniation severity types. In all of the osteoclastogenesis related cytokines, the IGF-1 and MCP-1 were the most highly expressed in the nucleus pulposus cells. IGF-1 enhances activation of NF-kB signaling directly, but MCP-1 upregulated the expression of RANK, so that enhanced cellular sensitivity to RANKL resulted in increasing osteoclastogenesis and activity. Conclusion: Lumbar herniation induced overexpression of IGF-1 and MCP-1 in nucleus pulposus cells aggravated vertebral erosions. Hence, this study suggests that targeting osteoclastogenesis related cytokines has potential clinical significance in the treatment of lumbar disc herniation patients.

Zhu, Zhongjiao; Huang, Peng; Chong, Yanxue; George, Suraj K; Wen, Bingtao; Han, Na; Liu, Zhiqiang; Kang, Lixin; Lin, Nie

2014-01-01

32

[Value of computed tomography in the differential diagnosis of postoperative lumbar disc herniation recurrence and fibrotic changes].  

PubMed

Plain computed tomography scans and after intravenous contrast enhancement were used to investigate a group of 26 patients after an operation for lumbar disc herniation with signs of failed back surgery syndrome. The diagnosis of relapsing disc herniation was established in 12 patients. It was confirmed by surgery in 10, while massive epidural fibrosis was discovered in two. Own experience with the above method, which is considered by the authors the most reliable, is presented. PMID:7976673

Burval, S; Nekula, J; Vaverka, M; Velísková, J; Klaus, E

1993-01-01

33

A History of Lumbar Disc Herniation From Hippocrates to the 1990s.  

PubMed

In ancient times, a supernatural understanding of the syndrome of lumbar radiculopathy often involved demonic forces vexing the individual with often crippling pain. The ancient Greeks and Egyptians began to take a more naturalistic view and, critically, suspected a relationship between lumbar spinal pathology and leg symptoms. Relatively little then changed for those with sciatica until the classic works by Cotugno and Kocher arrived in the late 18th century. Early lumbar canal explorations were performed in the late 1800s and early 1900s by MacEwen, Horsley, Krause, Taylor, Dandy, and Cushing, among others. In these cases, when compressive pathologies were found and removed, the lesions typically were (mis-)identified as enchondromas or osteochondritis dissecans. To better understand the history, learn more about the first treatments of lumbar disc herniation, and evaluate the impact of the early influences on modern spine practice, searches of PubMed and Embase were performed using the search terms discectomy, medical history, lumbar spine surgery, herniated disc, herniated nucleus pulposus, sciatica, and lumbar radiculopathy. Additional sources were identified from the reference lists of the reviewed papers. Many older and ancient sources including De Ischiade Nervosa are available in English translations and were used. When full texts were not available, English abstracts were used. The first true, intentional discectomy surgery was performed by Mixter and Barr in 1932. Early on, a transdural approach was favored. In 1938, Love described the intralaminar, extradural approach. His technique, although modified with improved lighting, magnification, and retractors, remains a staple approach to disc herniations today. Other modalities such as chymopapain have been investigated. Some remain a part of the therapeutic armamentarium, whereas others have disappeared. By the 1970s, CT scanning after myelography markedly improved the clinical evaluation of patients with lumbar disc herniation. In this era, use of discectomy surgery increased rapidly. Even patients with very early symptoms were offered surgery. Later work, especially by Weber and Hakelius, showed that many patients with lumbar disc herniation would improve without surgical intervention. In the ensuing decades, the debate over operative indications and timing continued, reaching another pivotal moment with the 2006 publication of the initial results of Spine Patient Outcomes Research Trial. PMID:24752913

Truumees, Eeric

2014-04-22

34

Proinflammatory Cytokine Expression Profile in Degenerated and Herniated Human Intervertebral Disc Tissues  

PubMed Central

Objective Prior reports document macrophage and lymphocyte infiltration with proinflammatory cytokine expression in pathologic intervertebral disc (IVD) tissues. Nevertheless, the role of the Th17 lymphocyte lineage in mediating disc disease remains uninvestigated. We undertook this study to evaluate the immunophenotype of pathologic IVD specimens, including interleukin-17 (IL-17) expression, from surgically obtained IVD tissue and from nondegenerated autopsy control tissue. Methods Surgical IVD tissues were procured from patients with degenerative disc disease (n = 25) or herniated IVDs (n = 12); nondegenerated autopsy control tissue was also obtained (n = 8) from the anulus fibrosus and nucleus pulposus regions. Immunohistochemistry was performed for cell surface antigens (CD68 for macrophages, CD4 for lymphocytes) and various cytokines, with differences in cellularity and target immunoreactivity scores analyzed between surgical tissue groups and between autopsy control tissue regions. Results Immunoreactivity for IL-4, IL-6, IL-12, and interferon-? (IFN?) was modest in surgical IVD tissue, although expression was higher in herniated IVD samples and virtually nonexistent in control samples. The Th17 lymphocyte product IL-17 was present in >70% of surgical tissue fields, and among control samples was detected rarely in anulus fibrosus regions and modestly in nucleus pulposus regions. Macrophages were prevalent in surgical tissues, particularly herniated IVD samples, and lymphocytes were expectedly scarce. Control tissue revealed lesser infiltration by macrophages and a near absence of lymphocytes. Conclusion Greater IFN? positivity, macrophage presence, and cellularity in herniated IVDs suggests a pattern of Th1 lymphocyte activation in this pathology. Remarkable pathologic IVD tissue expression of IL-17 is a novel finding that contrasts markedly with low levels of IL-17 in autopsy control tissue. These findings suggest involvement of Th17 lymphocytes in the pathomechanism of disc degeneration. PMID:20222111

Shamji, Mohammed F.; Setton, Lori A.; Jarvis, Wingrove; So, Stephen; Chen, Jun; Jing, Liufang; Bullock, Robert; Isaacs, Robert E.; Brown, Christopher; Richardson, William J.

2010-01-01

35

Horner's syndrome secondary to intervertebral disc herniation at the level of T1-2.  

PubMed

A 54-year-old Caucasian woman presented with a 6?week history of periscapular pain and a T1 radiculopathy associated with Horner's syndrome. MRI of her cervicothoracic spine revealed an intervertebral disc herniation at the level of T1-2. During investigation she experienced some improvement in her symptoms and a conservative approach was pursued. At 6?months her pain and radiculopathy had resolved, and there was mild residual ptosis. PMID:24903729

Spacey, Kate; Zaidan, Ammar; Dannawi, Zaher; Khazim, Rabi; Khazim, R; Dannawi, Zaher; Dannawi, Z

2014-01-01

36

The clinical study of percutaneous disc decompression of treating herniation of cervical disc with Nd:YAG laser  

NASA Astrophysics Data System (ADS)

Objective: The possibility of PLDD (percutaneous laser disc decompression) and an ideal non-operative method which is long everlasting effect for PLDD was investigated. Methods: 159 patients of Cervical Disc Herniation with PLDD were studied. All the herniated discs were irradiated with 10­15J/S Nd:YAG laser quantum through optical-fiber under the supervision of C-arm X-ray. Results: All the patients were followed and reexamined CT or MRI after one to six months of PLDD. The result of cured (67.92%), excellent (24.53%), moderation (5.66%), non-effect (1.88%) was got. The excellent rate was 88.24%. The effective rate was 97.65%. Non-effective rate was 2.35%. Conclusion: When irradiated with Nd:YAG laser, the nucleus pulposus was vapouring, charring and coagulating. The volume and inner-pressure of the disc decreased. So the symptoms and signs improved. The main value of this methods were micro-damage, non-operation, no bleeding, no bone injury, good therapy effect, quick recovery, lesser pain, safety and excellent long everlasting effect. It is an ideal non-operative method of treating PLDD.

Zhang, Dianxue; Cheng, Hefu; Wang, Jindong

2005-07-01

37

Dorsal Extradural Lumbar Disc Herniation Causing Cauda Equina Syndrome : A Case Report and Review of Literature  

PubMed Central

A 73-year-old male presented with a rare dorsally sequestrated lumbar disc herniation manifesting as severe radiating pain in both leg, progressively worsening weakness in both lower extremities, and urinary incontinence, suggesting cauda equina syndrome. Magnetic resonance imaging suggested the sequestrated disc fragment located in the extradural space at the L4-L5 level had surrounded and compressed the dural sac from the lateral to dorsal sides. A bilateral decompressive laminectomy was performed under an operating microscope. A large extruded disc was found to have migrated from the ventral aspect, around the thecal sac, and into the dorsal aspect, which compressed the sac to the right. After removal of the disc fragment, his sciatica was relieved and the patient felt strength of lower extremity improved. PMID:20379476

Lee, Sang-Ho; Arbatti, Nikhil J.

2010-01-01

38

Lumbar Spine Disc Herniation Diagnosis with a Joint Shape Model  

E-print Network

Buffalo, Buffalo, NY, USA, gdhillon@proscan.com, Abstract. Lower Back Pain (LBP) is the second most common. Keywords: Lumbar Spine Diagnosis, MRI, Disc Degenerative Disease 1 Introduction Low Back Pain has a major Alomari et al. for Low Back Pain [2]. Low back Pain has high societal impact as it disrupts individ- uals

Corso, Jason J.

39

Percutaneous endoscopic cervical discectomy for discogenic cervical headache due to soft disc herniation.  

PubMed

A discogenic cervical headache is a subtype of cervicogenic headache (CEH) that arises from a degenerative cervical disc abnormality. The purpose of this study was to evaluate the clinical outcome of percutaneous endoscopic cervical discectomy (PECD) for patients with chronic cervical headache due to soft cervical disc herniation. Seventeen patients underwent PECD for intractable headache. The inclusion criteria were soft disc herniation without segmental instability, proven by both local anesthesia and provocative discography for headache unresponsive to conservative treatment. The mean follow-up period was 37.6 months. Fifteen of the 17 patients (88.2%) showed successful outcomes based on the Macnab criteria. Pain scores on a visual analog scale (VAS) improved from a preoperative mean of 8.35 +/- 0.79 to 2.12 +/- 1.17, postoperatively (P < 0.01). The mean disc height decreased from 6.81 +/- 1.08 to 5.98 +/- 1.07 mm (P < 0.01). There was no newly developed segmental instability or spontaneous fusion on follow-up radiography. In conclusion, PECD appears to be effective for chronic severe discogenic cervical headache under strict inclusion criteria. PMID:16133482

Ahn, Y; Lee, S H; Chung, S E; Park, H S; Shin, S W

2005-12-01

40

Acute paraplegia secondary to thoracic disc herniation of the adjacent segment following thoracolumbar fusion and instrumentation.  

PubMed

Proximal junctional disease is a well-recognized postoperative phenomenon in adults who are undergoing long thoracolumbar fusion and instrumentation, and is attributed to increased a junctional stress concentration. In general, the onset of symptoms in these patients is insidious and the disease progresses slowly. We report on a contrary case of rapidly progressing paraplegia secondary to acute disc herniation at the proximal adjacent segment after long posterior thoracolumbar fusion with cement augmentation at the upper instrumented vertebra and the supra-adjacent vertebra. The patient was treated with a discectomy through the costo-transverse approach combined with extension of the posterior instrumentation. The patient's neurological status improved markedly. Stress concentration at the proximal junction disc space may have caused accelerated disc degeneration which in turn lead to this complication. PMID:23508671

Badra, Mohammad Ibrahim; Assaker, Richard; Musharrafieh, Ramzi Sharif

2013-03-01

41

A Novel Approach to the Surgical Treatment of Lumbar Disc Herniations: Indications of Simple Discectomy and Posterior Transpedicular Dynamic Stabilization Based on Carragee Classification  

PubMed Central

Surgery of lumbar disc herniation is still a problem since Mixter and Barr. Main trouble is dissatisfaction after the operation. Today there is a debate on surgical or conservative treatment despite spending great effort to provide patients with satisfaction. The main problem is segmental instability, and the minimally invasive approach via microscope or endoscope is not necessarily appropriate solution for all cases. Microsurgery or endoscopy would be appropriate for the treatment of Carragee type I and type III herniations. On the other hand in Carragee type II and type IV herniations that are prone to develop recurrent disc herniation and segmental instability, the minimal invasive techniques might be insufficient to achieve satisfactory results. The posterior transpedicular dynamic stabilization method might be a good solution to prevent or diminish the recurrent disc herniation and development of segmental instability. In this study we present our experience in the surgical treatment of disc herniations. PMID:23653862

Ozer, A. F.; Keskin, F.; Oktenoglu, T.; Suzer, T.; Ataker, Y.; Gomleksiz, C.; Sasani, M.

2013-01-01

42

A comparison of minimally invasive techniques in percutaneous treatment of lumbar herniated discs. A review.  

PubMed

Low back pain is the commonest spine disease causing absence from work in developed countries. Low back pain with classical irradiation along the course of the nerve root affected is more frequently due to disc disease. In 60-80% of patients with herniated disc, radicular symptoms disappear with conservative treatment after about six weeks, the remainder are treated surgically with a 2-6% of incidence of true recurrence of herniation post-intervention and with failed back surgery syndrome in 15% of cases. Recently minimally invasive techniques have developed as "alternative" treatments to surgical intervention. This review aimed to assess the pathogenesis of low back pain caused by lumbar disc hernia as a basis for action of minimally invasive techniques; to illustrate the techniques already used or currently in use, to compare them in technical guidance, indications and complications, exposing for each of them the inclusion/exclusion criteria in enrolling patients and the imaging guide technique of choice. Minimally invasive techniques can be a valuable alternative to traditional surgery with low cost, low risk of complications, easy feasibility, and in the event of failure they do not exclude subsequent surgery. PMID:24206960

Guarnieri, G; Vassallo, P; Pezzullo, M G; Laghi, F; Zeccolini, F; Ambrosanio, G; Galasso, R; Muto, M; Izzo, R

2009-03-23

43

Management of Chronic Pain of Cervical Disc Herniation and Radiculitis with Fluoroscopic Cervical Interlaminar Epidural Injections  

PubMed Central

Study Design: A randomized, double-blind, active controlled trial. Objective: To evaluate the effectiveness of cervical interlaminar epidural injections of local anesthetic with or without steroids in the management of chronic neck pain and upper extremity pain in patients with disc herniation and radiculitis. Summary of Background Data: Epidural injections in managing chronic neck and upper extremity pain are commonly employed interventions. However, their long-term effectiveness, indications, and medical necessity, of their use and their role in various pathologies responsible for persistent neck and upper extremity pain continue to be debated, even though, neck and upper extremity pain secondary to disc herniation and radiculitis, is described as the common indication. There is also paucity of high quality literature. Methods: One-hundred twenty patients were randomly assigned to one of 2 groups: Group I patients received cervical interlaminar epidural injections of local anesthetic (lidocaine 0.5%, 5 mL); Group II patients received 0.5% lidocaine, 4 mL, mixed with 1 mL of nonparticulate betamethasone. Primary outcome measure was ? 50 improvement in pain and function. Outcome assessments included Numeric Rating Scale (NRS), Oswestry Disability Index (ODI), opioid intake, employment, and changes in weight. Results: Significant pain relief and functional status improvement (? 50%) was demonstrated in 72% of patients who received local anesthetic only and 68% who received local anesthetic and steroids. In the successful group of participants, significant improvement was illustrated in 77% in local anesthetic group and 82% in local anesthetic with steroid group. Conclusions: Cervical interlaminar epidural injections with or without steroids may provide significant improvement in pain and function for patients with cervical disc herniation and radiculitis. PMID:22859902

Manchikanti, Laxmaiah; Cash, Kimberly A.; Pampati, Vidyasagar; Wargo, Bradley W.; Malla, Yogesh

2012-01-01

44

Co-existence of L5-S1 disc herniation and conus medullaris ependymoma  

PubMed Central

INTRODUCTION The lumbar disc herniations are seen very common than spinal ependymomas in the neurosurgery polyclinic routine. PRESENTATION OF CASE In our case, both pathologies were seen at the most frequently located levels compatible with the literature. Aim of this case report is, to remind once more that, different pathologies can be found at the same time in a single patient; differential diagnosis must be done very carefully. DISCUSSION The routine Computed Tomography (CT) imaging for low back pain can not show the conus medullaris pathology. Spinal tumors or other similar pathologies should be kept in mind for differential diagnosis. A good medical history and a good physical examination must be completed before the final diagnosis. CONCLUSION Viewing of spinal canal with Magnetic Resonance Imaging (MRI) will be useful for the patients who we intend to do disc surgery. PMID:25460457

Mino?lu, Mustafa; Akkol, ?smail; Özdemir, Nail; Y?ld?r?m, Levent

2014-01-01

45

Describing a new syndrome in L5-S1 disc herniation: Sexual and sphincter dysfunction without pain and muscle weakness  

PubMed Central

Context: Little seems to be known about the sexual dysfunction (SD) in lumbar intervertebral disc herniation. Aims: Investigation of sexual and sphincter dysfunction in patient with lumbar disc hernitions. Settings and Design: A retrospective analysis. Materials and Methods: Sexual and sphincter dysfunction in patients admitted with lumbar disc herniations between September 2012-March 2014. Statistical Analysis Used: Statistical analysis was performed using the Predictive Analytics SoftWare (PASW) Statistics 18.0 for Windows (Statistical Package for the Social Sciences, SPSS Inc., Chicago, Illinois). The statistical significance was set at P < 0.05. The Wilcoxon signed ranks test was used to evaluate the difference between patients. Results: Four patients with sexual and sphincter dysfunction were found, including two women and two men, aged between 20 and 52 years. All of them admitted without low back pain. In addition, on neurological examination, reflex and motor deficit were not found. However, almost all patients had perianal sensory deficit and sexual and sphincter dysfunction. Magnetic resonance imaging (MRI) of three patients displayed a large extruded disc fragment at L5-S1 level on the left side. In fourth patient, there were not prominent disc herniations. There was not statistically significant difference between pre-operative and post-operative sexual function, anal-urethral sphincter function, and perianal sensation score. A syndrome in L5-S1 disc herniation with sexual and sphincter dysfunction without pain and muscle weakness was noted. We think that it is crucial for neurosurgeons to early realise that paralysis of the sphincter and sexual dysfunction are possible in patients with lumbar L5-S1 disc disease. Conclusion: A syndrome with perianal sensory deficit, paralysis of the sphincter, and sexual dysfunction may occur in patients with lumbar L5-S1 disc disease. The improvement of perianal sensory deficit after surgery was counteracted by a trend toward disturbed sexual function. Further researches are needed to explore the extent of this problem.

Akca, Nezih; Ozdemir, Bulent; Kanat, Ayhan; Batcik, Osman Ersagun; Yazar, Ugur; Zorba, Orhan Unal

2014-01-01

46

Treatment of contained lumbar disc herniations using radiofrequency assisted micro-tubular decompression and nucleotomy: four year prospective study results  

PubMed Central

Background Patients with radiculopathy caused by contained disc herniations are less likely to have good outcomes following discectomy surgery than patients with disc herniations that are not contained. The author presents his 4-year results from a prospective trial regarding the efficacy and safety of a tubular transforaminal radiofrequency-assisted manual decompression and annulus modulation of contained disc herniations in 58 patients. Methods Fifty-eight patients with lumbar radiculopathy due to a contained disc herniation were enrolled in a prospective clinical study. Visual analog scores (VAS) for back pain and leg pain, quality of life assessment, Macnab criteria, and SF-12 were collected from patients before treatment, at 2-years and 4-years post-treatment. Results At 4 years, results were obtained from 47 (81%) of patients. Compared to mean pre- treatment assessments, mean 4-year VAS for back pain improved from 8.6 to 2.3 points, and mean VAS for leg pain improved from 7.8 to 2.3. Eighty-three percent of respondents reported that they were “satisfied” or “very satisifed” with their quality of life at 4-years as per SF-12. At 4 years, recurrence was noted in 3 (6.4%) of respondents and no complications were reported. Conclusions The 2-year and 4-year study results are nearly identical, suggesting durable benefit out to 4 years. These results also suggest that in carefully selected patients with sustained contained disc herniations who have failed conservative treatments, manual decompression combined with radiofrequency-assisted decompression and annulus modulation are very likely to have good outcomes 4 years post-treatment.

2014-01-01

47

The Influence of Obesity on the Outcome of Treatment of Lumbar Disc Herniation  

PubMed Central

Background: Questions remain as to the effect that obesity has on patients managed for symptomatic lumbar disc herniation. The purpose of this study was to determine if obesity affects outcomes following the treatment of symptomatic lumbar disc herniation. Methods: An as-treated analysis was performed on patients enrolled in the Spine Patient Outcomes Research Trial for the treatment of lumbar disc herniation. A comparison was made between patients with a body mass index of <30 kg/m2 (nonobese) (n = 854) and those with a body mass index of ?30 kg/m2 (obese) (n = 336). Baseline patient demographic and clinical characteristics were documented. Primary and secondary outcomes were measured at baseline and at regular follow-up time intervals up to four years. The difference in improvement from baseline between operative and nonoperative treatment was determined at each follow-up period for both groups. Results: At the time of the four-year follow-up evaluation, improvements over baseline in primary outcome measures were significantly less for obese patients as compared with nonobese patients in both the operative treatment group (Short Form-36 physical function, 37.3 compared with 47.7 points [p < 0.001], Short Form-36 bodily pain, 44.2 compared with 50.0 points [p = 0.005], and Oswestry Disability Index, ?33.7 compared with ?40.1 points [p < 0.001]) and the nonoperative treatment group (Short Form-36 physical function, 23.1 compared with 32.0 points [p < 0.001] and Oswestry Disability Index, ?21.4 compared with ?26.1 points [p < 0.001]). The one exception was that the change from baseline in terms of the Short Form-36 bodily pain score was statistically similar for obese and nonobese patients in the nonoperative treatment group (30.9 compared with 33.4 points [p = 0.39]). At the time of the four-year follow-up evaluation, when compared with nonobese patients who had been managed operatively, obese patients who had been managed operatively had significantly less improvement in the Sciatica Bothersomeness Index and the Low Back Pain Bothersomeness Index, but had no significant difference in patient satisfaction or self-rated improvement. In the present study, 77.5% of obese patients and 86.9% of nonobese patients who had been managed operatively were working a full or part-time job. No significant differences were observed in the secondary outcome measures between obese and nonobese patients who had been managed nonoperatively. The benefit of surgery over nonoperative treatment was not affected by body mass index. Conclusions: Obese patients realized less clinical benefit from both operative and nonoperative treatment of lumbar disc herniation. Surgery provided similar benefit over nonoperative treatment in obese and nonobese patients. Level of Evidence: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence. PMID:23192403

Rihn, Jeffrey A.; Kurd, Mark; Hilibrand, Alan S.; Lurie, Jon; Zhao, Wenyan; Albert, Todd; Weinstein, James

2013-01-01

48

Chiropractic/Rehabilitative Management of Post-Surgical Disc Herniation: A Retrospective Case Report  

PubMed Central

Abstract Objective To discuss management of postsurgical lumbar disc herniation using a program of chiropractic manipulation and an active rehabilitation program. Clinical Features The patient was a 54-year-old Caucasian male with a history of acute low back pain and left sciatic pain down the left posterior thigh and lateral calf and numbness in the dorsum of the left foot. Prior medical intervention included treatment with steroid anti-inflammatory drugs and lumbar microdiscectomy surgery, with incomplete resolution of his symptoms. The patient was unable to walk without pain or return to normal activities of daily living. He was antalgic in flexion. His lumbar range of motion was restricted in flexion and extension. He exhibited a positive straight leg raise and exhibited foot drop on the left. Intervention and Outcome The treatment plan and intervention consisted of patient education on proper posture and proper bending and lifting techniques. Rehabilitative exercise began in the office and progressed to home based therapy and exercises. He noticed a decrease in his signs and symptoms after seven visits. Active rehabilitation was continued with the goal of returning lumbar spinal extensor strength. He was released to home therapy and supportive chiropractic care with continued positive response. Conclusion Management of postsurgical lumbar disc herniation with chiropractic and active rehabilitation is discussed. Spinal deconditioning and a weakness of the lumbar spinal extensor muscles appeared to be related to the patient's symptoms. Patient education on proper posture, proper lifting techniques, core stabilization exercises, active strengthening exercise and chiropractic manipulation appeared effective in this case. PMID:19674632

Estadt, Gary M.

2004-01-01

49

Comparative Evaluation of Oxygen-Ozone Therapy and Combined Use of Oxygen-Ozone Therapy with Percutaneous Intradiscal Radiofrequency Thermocoagulation for the Treatment of Lumbar Disc Herniation  

Microsoft Academic Search

AimTo compare the efficacy of oxygen-ozone therapy and the combined use of oxygen-ozone therapy with percutaneous intradiscal radiofrequency thermocoagulation (PIRFT) for the treatment of contained lumbar disc herniation.

Sujeet Gautam; V. Rastogi; Ankur Jain; A. P. Singh

2011-01-01

50

Schmorl's nodes (intravertebral herniations of intervertebral disc tissue) in two historic British populations.  

PubMed Central

The herniation of the nucleus pulposus into the vertebral body produces ectopic deposit of disc material which are known as Schmorl's nodes. This prolapsed disc tissue leaves characteristic deformations on the surface of the vertebral body and hence the incidence of this lesion can be studied in skeletal remains. This report describes the occurrence of Schmorl's nodes in TV8-SV1 in two historic adult British populations, one from Aberdeen and the other from London. In the Aberdeen group, both males and females showed a high incidence rate and severity of Schmorl's nodes. In the London group, the males had a similarly high affliction whereas the females were nearly free of the condition. The lesion had no significant predilection for any one particular vertebral surface. However, in males in both localities, the frequency of Schmorl's nodes was significantly higher in the thoracic region than in the lumbosacral region. In contrast, both groups of females showed similar node frequency in these two zones. The majority of Schmorl's nodes were localised in the central and central-posterior regions of the vertebral surface. When nodes occurred on successive vertebral surfaces, they often formed sequences showing similar shape and position. The aetiology of Schmorl's nodes is unclear. Various hypothetical causal factors were appraised in relation to the findings of this study. It was suggested that anomalies in vascular and/or notochordal regression may be related to the development of the lesion. Images Fig. 2 Fig. 6 PMID:3323152

Saluja, G; Fitzpatrick, K; Bruce, M; Cross, J

1986-01-01

51

Operative management of lumbar disc herniation : the evolution of knowledge and surgical techniques in the last century.  

PubMed

Removal of a herniated disc with the use of the operative microscope was first performed by Yasargil (Adv Neurosurg. 4:81-2, 1977) in 1977. However, it began to be used more and more only in the late 1980s (McCulloch JA (1989) Principles of microsurgery for lumbar disc disease. Raven Press, New York). In the 1990s, many spinal surgeons abandoned conventional discectomy with naked-eye to pass to the routine practice of microdiscectomy. The merits of this technique are that it allows every type of disc herniation to be excised through a short approach to skin, fascia and muscles as well as a limited laminoarthrectomy. For these reasons, it has been, and still is, considered the "gold standard" of surgical treatment for lumbar disc herniation, and the method used by the vast majority of spinal surgeons. In the 1990s, the advent of MRI and the progressive increase in definition of this modality of imaging, as well as histopathologic and immunochemical studies of disc tissue and the analysis of the results of conservative treatments have considerably contributed to the knowledge of the natural evolution of a herniated disc. It was shown that disc herniation may decrease in size or disappear in a few weeks or months. Since the second half of the 1990s there has been a revival of percutaneous procedures. Some of these are similar to the percutaneous automated nucleotomy; other methods are represented by intradiscal injection of a mixture of "oxygen-ozone" (Alexandre A, Buric J, Paradiso R. et al. (2001) Intradiscal injection of oxygen ozone for the treatment of lumbar disc herniations: result at 5 years. 12th World Congress of Neurosurgery; 284-7), or laserdiscectomy performed under CT scan (Menchetti PPM. (2006) Laser Med Sci. 4:25-7). The really emerging procedure is that using an endoscope inserted into the disc through the intervertebral foramen to visualize the herniation and remove it manually using thin pituitary rongeurs, a radiofrequency probe or both (Chiu JC. (2004) Surg Technol Int. 13:276-86).Microdiscectomy is still the standard method of treatment due to its simplicity, low rate of complications and high percentage of satisfactory results, which exceed 90% in the largest series. Endoscopic transforaminal discectomy appears to be a reliable method, able to give similar results to microdiscectomy, provided the surgeon is expert enough in the technique, which implies a long learning curve in order to perform the operation effectively, with no complications. All the non-endoscopic percutaneous procedures now available can be used, but the patient must be clearly informed that while the procedure is simple and rapid, at least for the disc L4-L5 and those above (except for laserdiscectomy under CT, that can be easily performed also at L5-S1), their success rate ranges from 60 to 70% and that, in many cases, pain may decrease slowly and may take even several weeks to disappear. PMID:21107933

Postacchini, F; Postacchini, R

2011-01-01

52

Cervical Myelopathy Caused by Disc Herniation at the Segment of Existing Osteochondroma in a Patient with Hereditary Multiple Exostoses  

PubMed Central

Hereditary multiple exostoses (HME) is a benign hereditary disorder characterized by multiple osteochondromas. Osteochondroma appears occasionally in the spinal column as a part of HME. A 37-year-old man presented with a history of HME and cervical compressive myelopathy caused by intraspinal osteochondroma arising from the lamina of the C5 and disc herniation at the C5-6. He was treated by open-door laminoplasty at the C5 and C6 with excision of the tumor. The neurological symptoms were immediately relieved after surgery. Magnetic resonance images demonstrated a sufficient decompression of the spinal cord with a spontaneous regression of the herniated disc at one year after surgery. There was no recurrence of the tumor and no appearance of kyphosis and segmental instability of the cervical spine on postoperative imaging studies for three years after surgery. The patient could be successfully treated by laminoplasty with excision of the tumor and without removal of the herniated disc. PMID:25558330

Tarukado, Kiyoshi; Senba, Hideyuki; Kitamura, Takahiro; Komiya, Norihiro; Shidahara, Satoshi

2014-01-01

53

Intradural schwannoma complicated by lumbar disc herniation at the same level: A case report and review of the literature  

PubMed Central

Intradural tumours of the spine are usually benign and have a good prognosis, if they are diagnosed and removed early. Lumbar disc herniation is a common cause of chronic, acute, or recurrent lumbar radiculopathy. However, to date, there have been no reports of progressive neurological deficiencies due to the co-existence of two significant pathologies contributing to intradural and extradural compression. The current study reports the rare case of a patient with simultaneous extradural and intradural compression of the nerve root due to co-existent intervertebral disc herniation and an intradural schwannoma at the same level. A 71-year-old female suffering from lower back pain and radiating pain of the right lower extremities was admitted to Busan Korea Hospital (Busan, Korea). Magnetic resonance imaging revealed lumbar disc herniation at L4–5 and a mass occupying the intradural space at the same level of the compressed dural sac. Using the posterior approach, surgical excision of the two pathologies was performed. Pathological diagnosis confirmed schwannoma and the symptoms markedly improved. PMID:25013519

BAEK, SEUNG-WOOK; KIM, CHEOL; CHANG, HAN

2014-01-01

54

Cervical myelopathy caused by disc herniation at the segment of existing osteochondroma in a patient with hereditary multiple exostoses.  

PubMed

Hereditary multiple exostoses (HME) is a benign hereditary disorder characterized by multiple osteochondromas. Osteochondroma appears occasionally in the spinal column as a part of HME. A 37-year-old man presented with a history of HME and cervical compressive myelopathy caused by intraspinal osteochondroma arising from the lamina of the C5 and disc herniation at the C5-6. He was treated by open-door laminoplasty at the C5 and C6 with excision of the tumor. The neurological symptoms were immediately relieved after surgery. Magnetic resonance images demonstrated a sufficient decompression of the spinal cord with a spontaneous regression of the herniated disc at one year after surgery. There was no recurrence of the tumor and no appearance of kyphosis and segmental instability of the cervical spine on postoperative imaging studies for three years after surgery. The patient could be successfully treated by laminoplasty with excision of the tumor and without removal of the herniated disc. PMID:25558330

Ikuta, Ko; Tarukado, Kiyoshi; Senba, Hideyuki; Kitamura, Takahiro; Komiya, Norihiro; Shidahara, Satoshi

2014-12-01

55

Feasibility and Efficacy of Percutaneous Lateral Lumbar Discectomy in the Treatment of Patients with Lumbar Disc Herniation: A Preliminary Experience  

PubMed Central

Objective. This study was aimed at evaluating the effectiveness and safety of percutaneous lateral lumbar discectomy (PLLD) in treating patients with lumber disc herniation. Methods. A total of 183 patients with lumbar disc herniation were recruited to receive PLLD surgery from April 2006 to October 2011. All the adverse effects were recorded during the follow-up at 1, 3, 6, and 12 months after PLLD. The clinical outcomes were determined by visual analog scale and Japanese Orthopaedic Association score. Results. The surgery was performed successfully in all patients (102 males and 81 females aged from 21 to 66 years) with a mean 16.6-month follow-up (range from 26 to 65 months). No postoperative complications, including intestinal and vascular complications, nerve injuries, and postoperative infections, were associated with PLLD. At one month after surgery, visual analog scale (3.12±1.44 versus 6.76±2.31, P<0.05) was significantly lower than the baseline and was sustained until 24 months after surgery (3.25 ± 1.78 versus 6.76±2.31, P<0.05). Besides that, Japanese Orthopaedic Association score (25.25±3.21 versus 11.78±2.38, P<0.05) was increased when compared to the baseline. Conclusions. PLLD was a promising, mini-invasive, and effective treatment for lumber disc herniation.

Jiang, Wenjin; Sun, Bolin; Sheng, Qirui; Song, Xuepeng; Zheng, Yanbo; Wang, Ligang

2015-01-01

56

Pure traumatic upper cervical disc herniation causing spinal cord injury: a case report and review of literature  

PubMed Central

Abstract: One third of all spinal injuries involve cervical vertebrae, and the impact of injury to the cervical spinal cord is profound and requires systemic treatment. The role and timing of surgical decompression after an acute spinal cord injury (SCI) remains one of the most controversial topics pertaining to spinal surgery. Lack of controlled, prospective, multicenter clinical studies has contributed to confusion in optimal treatment methods for patients with injuries of the cervical spinal cord. Clinically, the question of whether surgical decompression improves motor recovery following SCI remains surrounded by controversy. Case: Two cases with a 32-year-old man who developed right -sided Brown-Séquard Syndrome Following a motor to car accident with the large right paramedian C3–C4 disc herniation, and ipsilateral spinal cord compression and a 30-year-old man with the syndrome of acute central cervical spinal cord injury with motor impairment involving only upper extremities due to central C2–C3 disc herniation following a pedestrian accident are reported. Discectomy and anterior cervical fusion with the polyetheretherketone (PEEK) cage were performed. A complete motor deficit recovery and a marked sensitive deficit improvement were obtained. The need for and timing of surgical decompression in post traumatic spinal cord injury is controversial. Surgery may expedite neurological recovery in some patients and may provide additional neurological recovery when clinical improvement has plateaued or worsened. In our patient a complete motor deficit recovery was observed. Keywords: Cervical, Disc herniation, Spinal cord injury

Sharifi, Guive; Mosavi, Seyed Ali; Shafieezad, Misagh; Asgari Nosari, Massoud

2012-01-01

57

A PHASED REHABILITATION PROTOCOL FOR ATHLETES WITH LUMBAR INTERVERTEBRAL DISC HERNIATION  

PubMed Central

Conservative non-surgical management of a herniated lumbar intervertebral disc (HLD) in athletes is a complex task due to the dramatic forces imparted on the spine during sport participation. The demands placed upon the athlete during rehabilitation and return to sport are unique not only from a sport specific perspective, but also regarding return to the sport strength and conditioning programs utilized for sport preparation. Many prescriptions fail to address postural and motor control faults specific to athletic development, which may prevent full return to sport after suffering a HLD or predispose the athlete to future exacerbations of a HLD. Strength exercises involving squatting, deadlifting, and Olympic power lifts are large components of the typical athlete's conditioning program, therefore some progressions are provided to address potential underlying problems in the athlete's technique that may have contributed to their HLD in the first place. The purpose of this clinical commentary is to propose a framework for rehabilitation that is built around the phases of healing of the disc. Phase I: Non-Rotational/Non-Flexion Phase (Acute Inflammatory Phase), Phase II: Counter rotation/Flexion Phase (Repair Phase), Phase III: Rotational Phase/Power development (Remodeling Phase), and Phase IV: Full return to sport. This clinical commentary provides a theoretical basis for these phases based on available literature as well as reviewing many popular current practice trends in the management of an HLD. The authors recognize the limits of any general exercise rehabilitation recommendation with regard to return to sport, as well as any general strength and conditioning program. It is vital that an individual assessment and prescription is made for every athlete which reviews and addresses movement in all planes of motion under all necessary extrinsic and intrinsic demands to that athlete. Level of Evidence: 5 PMID:24175134

VanGelder, Leonard H.; Vaughn, Daniel W.

2013-01-01

58

Genetic mapping of a susceptibility locus for disc herniation and spastic paraplegia on 6q23.3-q24.1  

PubMed Central

It has been suggested that a genetic factor(s) or a familial predisposition may contribute to the clinical manifestations of disc herniation; moreover, no genetic linkage between spinal disc herniation and spastic paraplegia has ever been described. A family with consanguineous parents and four of eight sibs affected by multiple disc herniations and spastic paraplegia was clinically and genetically analysed. Surgery caused partial improvement in all of them. After the exclusion of type II collagen and vitamin D receptor genes and the recessive loci for HSPs, a genome wide search was performed with about 500 fluorescent markers. Positive lod score values were obtained for chromosome 6q22.31-q24.1, with evidence of three homozygous intervals. The maximum multipoint lod score of 3.28 was obtained in only one interval, between markers D6S1699 and D6S314. On the whole, a susceptibility locus for disc herniation and autosomal recessive spastic paraplegia was found on chromosome 6q23.3-q24.1. This is the first time that disc herniation and the associated neurological syndrome has been linked to a human chromosomal region. PMID:12070243

Zortea, M; Vettori, A; Trevisan, C; Bellini, S; Vazza, G; Armani, M; Simonati, A; Mostacciuolo, M

2002-01-01

59

Instrumented transforaminal lumbar interbody fusion in surgical treatment of recurrent disc herniation  

PubMed Central

Background: The incidence of recurrence in patients undergoing primary discectomy due to lumbar disc herniation (LDH), is regularly reported as 5-15%. In this study we aimed to evaluate surgical outcome of instrumented transforaminal lumbar interbody fusion (TLIF) in the patients suffering from recurrent LDH. Methods: We retrospectively studied 51 patients (30 female, 21 male) from August 2007 to October 2011. The mean age and follow-up of the patients was 46.4±14.8 (ranged; 29-77 years old) and 31.4±6.8 (ranged; 25-50 months), respectively. Clinical improvement was assessed by Oswestry Disability Index (ODI), visual analogue scale (VAS), and subjective satisfaction rate, while fusion was appraised radiologically. Data analysis was by one sample Kolmogorov-Smirnov, paired t, and Mann-Whitney tests. Results: Surgery could significantly improve mean leg and lumbar VAS and ODI from preoperative 7.4±2.5, 7.8±3.1, and 72.1±21.5 to postoperative 3.4±3.6, 3.5±2.6, and 27.5±18.0, respectively at the last follow-up visit. Subjective satisfaction rate was excellent in 24 patients (47.1%), good in 14 (27.5%), fair 11 (21.6%), and poor in two (3.9%). We had one patient with iatrogenic partial L5 nerve root injury and one with unknown late onset refractory postoperative back pain. Fusion rate was 100% and instrument failure was nil. Conclusion: In surgical treatment of the patients with recurrent LDH, bilaterally instrumented TLIF is a relatively safe and effective procedure and can be associated with least instrument failure and highest fusion rate while no postoperative bracing is also needed.

Omidi-Kashani, Farzad; Ghayem Hasankhani, Ebrahim; Noroozi, Hamid Reza

2014-01-01

60

Do preoperative fear avoidance model factors predict outcomes after lumbar disc herniation surgery? A systematic review  

PubMed Central

Background Lumbar disc herniation (LDH) surgery is usually recommended when conservative treatments fail to manage patients’ symptoms. However, many patients undergoing LDH surgery continue to report pain and disability. Preoperative psychological factors have shown to be predictive for postoperative outcomes. Our aim was to systematically review studies that prospectively examined the prognostic value of factors in the Fear Avoidance Model (FAM), including back pain, leg pain, catastrophizing, anxiety, fear-avoidance, depression, physical activity and disability, to predict postoperative outcomes in patients undergoing LDH surgery. Methods We performed a systematic literature review of prospective studies that measured any FAM factors preoperatively to predict postoperative outcomes for patients undergoing LDH surgery. Our search databases included PubMed, CINAHL, and PsycINFO. We assessed the quality of each included study using a certain quality assessment list. Degree of agreement between reviewers on quality assessment was examined. Results related to FAM factors in the included studies were summarized. Results Thirteen prospective studies met our inclusion criteria. Most studies were considered high quality. Heterogeneity was present between the included studies in many aspects. The most common FAM factors examinered were baseline pain, disability and depression. In, general, depression, fear-avoidance behaviors, passive pain coping, and anxiety FAM factors appeared to have negative influence on LDH surgical outcome. Baseline back pain and leg pain appeared to have differing prognostic value on LDH surgical outcomes. Conclusions FAM factors seem to influence LDH surgical outcomes. Patients with high levels of depression, anxiety and fear-avoidance behaviors are more likely to have poor outcomes following LDH surgery. Conversely, high levels of leg pain, but not back pain seem to be predictor for favorable LDH surgery outcome. More research is needed to determine the exact role of FAM factors on LDH surgical outcome and the value for screening for these factors. PMID:24237581

2013-01-01

61

Efficacy of Epidural Neuroplasty Versus Transforaminal Epidural Steroid Injection for the Radiating Pain Caused by a Herniated Lumbar Disc  

PubMed Central

Objective To compare the treatment effects of epidural neuroplasty (NP) and transforaminal epidural steroid injection (TFESI) for the radiating pain caused by herniated lumbar disc. Methods Thirty-two patients diagnosed with herniated lumbar disc through magnetic resonance imaging or computed tomography were included in this study. Fourteen patients received an epidural NP and eighteen patients had a TFESI. The visual analogue scale (VAS) and functional rating index (FRI) were measured before the treatment, and at 2 weeks, 4 weeks and 8 weeks after the treatment. Results In the epidural NP group, the mean values of the VAS before the treatment, and at 2 weeks, 4 weeks and 8 weeks after the treatment were 7.00±1.52, 4.29±1.20, 2.64±0.93, 1.43±0.51 and those of FRI were 23.57±3.84, 16.50±3.48, 11.43±2.44, 7.00±2.15. In the TFESI group, the mean values of the VAS before the treatment, and at 2 weeks, 4 weeks and 8 weeks after the treatment were 7.22±2.05, 4.28±1.67, 2.56±1.04, 1.33±0.49 and those of FRI were 22.00±6.64, 16.22±5.07, 11.56±4.18, 8.06±1.89. During the follow-up period, the values of VAS and FRI within each group were significantly reduced (p<0.05) after the treatment. But there were no significant differences between the two groups statistically. Conclusion Epidural NP and TFESI are equally effective treatments for the reduction of radiating pain and for improvement of function in patients with a herniated lumbar disc. We recommend that TFESI should be primarily applied to patients who need interventional spine treatment, because it is easier and more cost-effective than epidural NP. PMID:24466517

Kim, Hae Jong; Rim, Byeong Cheol; Lim, Jeong-Wook; Park, Noh Kyoung; Kang, Tae-Wook; Sohn, Min Kyun; Beom, Jaewon

2013-01-01

62

Fluoroscopic caudal epidural injections in managing chronic axial low back pain without disc herniation, radiculitis, or facet joint pain  

PubMed Central

Background Chronic low back pain without disc herniation is common. Various modalities of treatments are utilized in managing this condition, including epidural injections. However, there is continued debate on the effectiveness, indications, and medical necessity of any treatment modality utilized for managing axial or discogenic pain, including epidural injections. Methods A randomized, double-blind, actively controlled trial was conducted. The objective was to evaluate the ability to assess the effectiveness of caudal epidural injections of local anesthetic with or without steroids for managing chronic low back pain not caused by disc herniation, radiculitis, facet joints, or sacroiliac joints. A total of 120 patients were randomized to two groups; one group did not receive steroids (group 1) and the other group did (group 2). There were 60 patients in each group. The primary outcome measure was at least 50% improvement in Numeric Rating Scale and Oswestry Disability Index. Secondary outcome measures were employment status and opioid intake. These measures were assessed at 3, 6, 12, 18, and 24 months after treatment. Results Significant pain relief and functional status improvement (primary outcome) defined as a 50% or more reduction in scores from baseline, were observed in 54% of patients in group 1 and 60% of patients in group 2 at 24 months. In contrast, 84% of patients in group 1 and 73% in group 2 saw significant pain relief and functional status improvement in the successful groups at 24 months. Conclusion Caudal epidural injections of local anesthetic with or without steroids are effective in patients with chronic axial low back pain of discogenic origin without facet joint pain, disc herniation, and/or radiculitis. PMID:23091395

Manchikanti, Laxmaiah; Cash, Kimberly A; McManus, Carla D; Pampati, Vidyasagar

2012-01-01

63

Use of Magnetic Resonance Imaging to Identify Outcome Predictors of Caudal Epidural Steroid Injections for Lower Lumbar Radicular Pain Caused by a Herniated Disc  

PubMed Central

Objective We used lumbar magnetic resonance image (MRI) findings to determine possible outcome predictors of a caudal epidural steroid injection (CESI) for radicular pain caused by a herniated lumbar disc (HLD). Methods Ninety-one patients with radicular pain whose MRI indicated a HLD were enrolled between September 2010 and July 2013. The CESIs were performed using ultrasound (US). A responder was defined as having complete relief or at least a 50% reduction of pain as assessed by the visual analog scale (VAS) and functional status on the Roland Morris Disability Questionnaire (RMDQ); responder (VAS n=61, RMDQ n=51), and non-responder (VAS n=30, RMDQ n=40). MRI findings were analyzed and compared between the two groups with regard to HLD level, HLD type (protrusion or exclusion), HLD zone (central, subarticular, foraminal, and extraforaminal), HLD volume (mild, moderate, or severe), relationship between HLD and nerve root (no contact, contact, displaced, or compressed), disc height loss (none, less than half, or more than half ), and disc degeneration grade (homogeneous disc structure or inhomogeneous disc structure-clear nucleus and height of intervertebral disc). Results A centrally located herniated disc was more common in the responder group than that in the non-responder group. Treatment of centrally located herniated discs showed satisfactory results. (VAS p=0.025, RMDQ p=0.040). Other factors, such as HLD level, HLD type, HLD volume, relationship to nerve root, disc height loss, and disc degeneration grade, were not critical. Conclusion The HLD zone was significant for pain reduction after CESI. A centrally located herniated disc was a predictor of a good clinical outcome.

Cha, Sung Oh; Jang, Chul Hoon; Hong, Jin Oh; Park, Joon Sang

2014-01-01

64

Acute spontaneous cervical disc herniation causing rapidly progressive myelopathy in a patient with comorbid ossified posterior longitudinal ligament: Case report and literature review  

PubMed Central

Background: Ossification of the posterior longitudinal ligament (OPLL) and cervical disc herniation are commonly encountered neurosurgical conditions. Here we present an unusual case of nontraumatic rapidly progressive myelopathy due to cervical disc herniation with comorbid OPLL and conduct a literature review focusing on the frequency and management of disc herniations with OPLL. Case Description: A 52-year-old healthy female presented with a 72-h history of rapid progression of dense quadriparesis with sensory deficits, with a precedent 4-week history of nontraumatic midline neck pain. Clinical examination revealed profound motor deficits below the C5 myotome. Spinal neuroimaging revealed OPLL (computed tomography [CT]) and a cervical disc herniation spanning from C4/5 to C5/6 with significant retrovertebral disease (magnetic resonance imaging [MRI]). Operative management involved an anterior cervical corpectomy and instrumented fusion, with removal of both the sequestered disc material and the locally compressive OPLL. The patient recovered full motor function and independent ambulation with no residual signs or symptoms of myelopathy at the time of discharge. Conclusion: This unique case of a spontaneous cervical disc herniation in the context of OPLL causing rapidly progressive myelopathy illustrates the complementarity of CT and MRI in diagnosing the underlying cause of a rapidly progressive neurologic deficit in the absence of antecedent trauma. Though the optimal surgical management of such pathology remains uncertain; in this case, the anterior approach was motivated by the significant retrovertebral ventrally compressive sequestrum, and provided for excellent neurologic outcome. This article also reviews the occurrence/management of such acute cervical discs with OPLL. PMID:25289163

Westwick, Harrison J.; Goldstein, Christina L.; Shamji, Mohammed F.

2014-01-01

65

Hemifacial hyperhidrosis associated with ipsilateral/contralateral cervical disc herniation myelopathy. Functional considerations on how compression pattern determines the laterality  

PubMed Central

Summary Sweating is an important mechanism for ensuring constant thermoregulation, but hyperhidrosis may be disturbing. We present five cases of hemifacial hyperhidrosis as a compensatory response to an/hypohidrosis caused by cervical disc herniation. All the patients complained of hemifacial hyperhidrosis, without anisocoria or blepharoptosis. Sweat function testing and thermography confirmed hyperhidrosis of hemifacial and adjacent areas. Neck MRI showed cervical disc herniation. Three of the patients had lateral compression with well-demarcated hypohidrosis below the hyperhidrosis on the same side as the cervical lesion. The rest had paramedian compression with poorly demarcated hyperhidrosis and hypohidrosis on the contralateral side. Although MRI showed no intraspinal pathological signal intensity, lateral dural compression might influence the circulation to the sudomotor pathway, and paramedian compression might influence the ipsilateral sulcal artery, which perfuses the sympathetic descending pathway and the intermediolateral nucleus. Sweat function testing and thermography should be performed to determine the focus of the hemifacial hyperhidrosis, and the myelopathy should be investigated on both sides. PMID:25014051

Iwase, Satoshi; Inukai, Yoko; Nishimura, Naoki; Sato, Maki; Sugenoya, Junichi

2014-01-01

66

Gene expression profile analysis of human mesenchymal stem cells from herniated and degenerated intervertebral discs reveals different expression of osteopontin.  

PubMed

Gene expression analysis provides an effective methodology to identify clinically relevant genes implicated in intervertebral disc (IVD) pathology. The analysis of gene profile in mesenchymal stem cells (MSCs) from human herniated IVD (H-IVD) and degenerated IVD (D-IVD) has not yet been investigated. We present in this study a characterization of MSCs isolated from clinically categorized H-IVD and D-IVD disc samples. H-IVD-MSCs and D-IVD-MSCs showed multipotent mesenchymal differentiation ability, expressing positivity for adipogenic, osteogenic, and chondrogenic markers with an immunophenotypical profile representative of MSCs. FACS analyses revealed a higher expression of CD44 in D-IVD-MSCs compared to H-IVD-MSCs. Gene expression profile revealed that most genes under investigation displayed large variations and were not significantly different in the two types of analyzed IVD-MSCs. Conversely, the gene expression of osteopontin (OPN), a protein involved in bone matrix mineralization and extracellular matrix destruction, was found markedly increased (more than 400-fold) in D-IVD-MSCs compared to H-IVD-MSCs. Moreover, the OPN protein expression was detectable only in D-IVD-MSCs, and its levels were directly related with D-IVD severity. These findings suggest that an abnormal expression of OPN in D-IVD-MSCs occurs and plays a pivotal role in the pathophysiological process of human disc degeneration. We speculate that the regulation of the OPN pathway might be a therapeutic target to counteract disc degeneration. PMID:25203751

Marfia, Giovanni; Navone, Stefania Elena; Di Vito, Clara; Tabano, Silvia; Giammattei, Lorenzo; Di Cristofori, Andrea; Gualtierotti, Roberta; Tremolada, Carlo; Zavanone, Mario; Caroli, Manuela; Torchia, Francesco; Miozzo, Monica; Rampini, Paolo; Riboni, Laura; Campanella, Rolando

2015-02-01

67

Long-Term Outcomes of Patients with Lumbar Disc Herniation Treated with Percutaneous Discectomy: Comparative Study with Microendoscopic Discectomy  

SciTech Connect

We assessed the long-term outcomes of patients with lumbar disc herniation treated with percutaneous lumbar discectomy (PLD) or microendoscopic discectomy (MED). A retrospective study was performed in consecutive patients with lumbar disc herniation treated with PLD (n = 129) or MED (n = 101) in a single hospital from January 2000 to March 2002. All patients were followed up with MacNab criteria and self-evaluation questionnaires comprising the Oswestry Disability Index and Medical Outcomes Study 36-Item Short-Form Health Survey. Several statistical methods were used for analyses of the data, and a p value of <0.05 was considered to be statistically significant. A total of 104 patients (80.62%) with PLD and 82 patients (81.19%) with MED were eligible for analyses, with a mean follow-up period of 6.64 {+-} 0.67 years and 6.42 {+-} 0.51 years, respectively. There were no significant differences between the two groups in age, number of lesions, major symptoms and physical signs, and radiological findings. According to the MacNab criteria, 75.96% in the PLD group and 84.15% in the MED group achieved excellent or good results, respectively, this was statistically significant (p = 0.0402). With the Oswestry Disability Index questionnaires, the average scores and minimal disability, respectively, were 6.97 and 71.15% in the PLD group and 4.89 and 79.27% in the MED group. Total average scores of Medical Outcomes Study 36-Item Short-Form Health Survey were 75.88 vs. 81.86 in PLD group vs. MED group (p = 0.0582). The cost and length of hospitalization were higher or longer in MED group, a statistically significant difference (both p < 0.0001). Long-term complications were observed in two patients (2.44%) in the MED group, no such complications were observed in the PLD group. Both PLD and MED show an acceptable long-term efficacy for treatment of lumbar disc herniation. Compared with MED patients, long-term satisfaction is slightly lower in the PLD patients; complications, hospitalization duration, and costs in PLD group are also lower.

Liu Wengui [Southeast University, Department of Radiology, Zhong-Da Hospital (China); Wu Xiaotao [Southeast University, Department of Orthopedics, Zhong-Da Hospital (China); Guo Jinhe [Southeast University, Department of Radiology, Zhong-Da Hospital (China); Zhuang Suyang [Southeast University, Department of Orthopedics, Zhong-Da Hospital (China); Teng Gaojun, E-mail: gjteng@vip.sina.co [Southeast University, Department of Radiology, Zhong-Da Hospital (China)

2010-08-15

68

Cytokine expression in the epidural space: a model of non-compressive disc herniation-induced inflammation  

PubMed Central

Study Design Animal study Objective Development of an animal model for the study of biochemical changes that occur in the epidural space after intervertebral disc herniation. Summary of Background Data Although strong evidence for an inflammatory component exists, the biochemical processes underlying pain following disc herniation remain unknown. Methods Epidural lavage was performed in 48 rats after L5 dorsal root ganglion (DRG) exposure at baseline and 3, 6, or 24 hours after placement of autologous nucleus pulposus (NP) (N = 15), saline (N = 15), or NP + an interferon-gamma antibody (anti-IFN?; N = 18) directly onto the DRG. Multiplex assays quantifying interleukin (IL-)-1-?, IL-1?, IL-2, IL-4, IL-6, IL-10, TNF?, IFN? and GM-CSF were performed. NP (N = 7) was also analyzed for these cytokines by placing NP into saline and measuring the relative concentration. Results Cytokines measured low at baseline (0–100pg/ml) in all groups. Compared to saline, NP application caused IL-6 elevation, peaking at T=3hr, that was prevented by anti-IFN?. NP induced elevation of TNF?, peaking at T=24hr and was prevented by anti-IFN?. IFN? was elevated after NP at T=3hr and T=24hr. IL-1? was similar after saline versus NP. The concentrations of IL-1? and IL-10 were elevated at T=3hr, 6hr and 24hr in all groups without between-groups difference. The level of IL-4 peaked at T=3hr in the NP group and was different than saline and NP +anti-IFN? groups but the time effect was insignificant. There was no change for GM-CSF. The concentration of cytokines measured in normal NP was < 2pg/ml for all cytokines except TNF?. Conclusion In this model of acute non-compressive disc herniation, NP caused the elevation of epidural IL-6, TNF? and IFN?; all attenuated by IFN? blockade. IL-1? and IL-10 were both significantly elevated by saline alone and their response was not prevented by IFN? blockade. This model may prove useful for the study of the biochemical processes by which NP induces inflammation-induced nerve root irritation and radiculopathic pain. PMID:22648034

Cuellar, Jason M.; Borges, Paula M.; Cuéllar, Vanessa Gabrovsky; Yoo, Andrew; Scuderi, Gaetano J.; Yeomans, David C.

2012-01-01

69

The Surgical Treatment of Single Level Multi-Focal Subarticular and Paracentral and/or Far-Lateral Lumbar Disc Herniations: The Single Incision Full Endoscopic Approach  

PubMed Central

Background Surgery for same level multi-focal extruded lumbar disc herniations is technically challenging and the optimal method controversial. The subarticular disc herniation may pose the most challenging subtype requiring partial or complete facetectomy with or without fusion. The far-lateral disc herniation, often treated using a Wiltse approach, can also be difficult to access especially in the obese patient. When both the subarticular and far-lateral subtypes are simultaneously present at the same level with or without a paracentral disc herniation, a total facetectomy and interbody fusion (TLIF) or a total disc replacement (TDR) may be necessary. Endoscopic surgical techniques may reduce the need for these more invasive methods. Methods Fifteen patients (6 male and 9 female) who had same level multi-focal (subarticular as well as far-lateral and/or paracentral) extruded disc herniations underwent single incision unilateral endoscopic disc excision by the same surgeon at a single institution. Patients were prospectively followed for an average of 15.3 months (range 14-18 months) and outcomes were evaluated radiographically and clinically (Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI). Results The mean operative time was 52 minutes with minimal blood loss in all cases. Fourteen of the 15 patients were discharged to home on the day of their surgery. The mean ODI and leg VAS scores improved from 22.9 ± 3.2 to 12.9 ± 2.7 (p < 0.005), and from 8.6 ± 1.6 to 2.1 + 0.4 (p < 0.005), respectively. Conclusions After an average of 15.3 months of follow-up, the clinical and radiographic results of full endoscopic surgical treatment of single level multi-focal (subarticular as well as far-lateral and/or paracentral) disc herniations are excellent. This study is a case series with mid-term follow-up (Level IV). Clinical Relevance Foraminal and extra-foraminal full endoscopic decompression appears to offer a safe minimally invasive solution to a complex pathologic problem. PMID:25694941

Scott, David L.; Han, Xiao; Yacob, Alem

2014-01-01

70

Minimally invasive surgery for synchronous, same-level lumbar intradural-extramedullary neoplasm and acute disc herniation.  

PubMed

Schwannomas are the most common intradural-extramedullary spinal tumors, with an estimated incidence of 3 to 10 cases per 100,000 people. With continued advances in minimally invasive surgery (MIS) over recent years, MIS techniques have been utilized by spine surgeons in the resection of intradural spinal neoplasms with favorable surgical results and clinical outcomes. This video demonstrates a rare case of symptomatic, synchronous, same-level lumbar intradural-extramedullary neoplasm and acute disc herniation, both of which were successfully treated using a single MIS approach. Surgical pearls and nuances are discussed to better delineate technique and minimize potential complications. The video can be found here: http://youtu.be/78ibbicBRUk. PMID:25175577

Tan, Lee A; Kasliwal, Manish K; Wewel, Joshua; Fontes, Ricardo B V; O'Toole, John E

2014-09-01

71

Oxygen-ozone therapy for herniated lumbar disc in patients with subacute partial motor weakness due to nerve root compression.  

PubMed

Intradiscal oxygen-ozone (O2-O3) chemonucleolysis is a well-known effective treatment for pain caused by protruding disc disease and nerve root compression due to bulging or herniated disc. The most widely used therapeutic combination is intradiscal injection of an O2-O3 mixture (chemonucleolysis), followed by periradicular injection of O2-O3, steroid and local anaesthetic to enhance the anti-inflammatory and analgesic effect. The treatment is designed to resolve pain and is administered to patients without motor weakness, whereas patients with acute paralysis caused by nerve root compression undergo surgery 24-48h after the onset of neurological deficit. This paper reports on the efficacy of O2-O3 chemonucleolysis associated with anti-inflammatory foraminal injection in 13 patients with low back pain and cruralgia, low back pain and sciatica and subacute partial motor weakness caused by nerve root compression unresponsive to medical treatment. All patients were managed in conjunction with our colleagues in the Neurosurgery Unit of Bellaria Hospital and the IRCCS Institute of Neurological Sciences, Bologna. The outcomes obtained are promising: 100% patients had a resolution of motor weakness, while 84.6% had complete pain relief. Our results demonstrate that O2-O3 therapy can be considered a valid treatment option for this category of patients. PMID:25363257

Dall'Olio, Massimo; Princiotta, Ciro; Cirillo, Luigi; Budai, Caterina; de Santis, Fabio; Bartolini, Stefano; Serchi, Elena; Leonardi, Marco

2014-10-31

72

Higher preoperative Oswestry Disability Index is associated with better surgical outcome in upper lumbar disc herniations  

Microsoft Academic Search

To evaluate the surgical outcome in terms of functional and subjective recovery, patients who needed discectomies at L1–L2,\\u000a L2–L3 and L3–L4 levels were compared with an age and sex-matched group of patients who required L4–L5 and L5–S1 discectomies.\\u000a We prospectively enrolled 50 consecutive patients, referred to our center, who had L1–L2, L2–L3 and L3–L4 herniations and\\u000a required surgical intervention. Likewise,

Hooshang Saberi; Arash Vatankhahan Isfahani

2008-01-01

73

Comparison of the Efficacy of Caudal, Interlaminar, and Transforaminal Epidural Injections in Managing Lumbar Disc Herniation: Is One Method Superior to the Other?  

PubMed Central

Background Epidural injections are performed utilizing 3 approaches in the lumbar spine: caudal, interlaminar, and transforaminal. The literature on the efficacy of epidural injections has been sporadic. There are few high-quality randomized trials performed under fluoroscopy in managing disc herniation that have a long-term follow-up and appropriate outcome parameters. There is also a lack of literature comparing the efficacy of these 3 approaches. Methods This manuscript analyzes data from 3 randomized controlled trials that assessed a total of 360 patients with lumbar disc herniation. There were 120 patients per trial either receiving local anesthetic alone (60 patients) or local anesthetic with steroids (60 patients). Results Analysis showed similar efficacy for caudal, interlaminar, and transforaminal approaches in managing chronic pain and disability from disc herniation. The analysis of caudal epidural injections showed the potential superiority of steroids compared with local anesthetic alone a 2-year follow-up, based on the average relief per procedure. In the interlaminar group, results were somewhat superior for pain relief in the steroid group at 6 months and functional status at 12 months. Interlaminar epidurals provided improvement in a significantly higher proportion of patients. The proportion of patients nonresponsive to initial injections was also lower in the group for local anesthetic with steroid in the interlaminar trial. Conclusions The results of this assessment show significant improvement in patients suffering from chronic lumbar disc herniation with 3 lumbar epidural approaches with local anesthetic alone, or using steroids with long-term follow-up of up to 2 years, in a contemporary interventional pain management setting. PMID:25589942

Singh, Vijay; Pampati, Vidyasagar; Falco, Frank JE; Hirsch, Joshua A.

2015-01-01

74

Effects of Acupuncture, Core-stability Exercises, and Treadmill Walking Exercises in Treating a Patient with Postsurgical Lumbar Disc Herniation: A Clinical Case Report.  

PubMed

The objective of this study is to investigate the effects of acupuncture, core-stability exercises, and treadmill 12-minute walking exercises in treating patients with postsurgical lumbar disc herniation. A 34-year-old woman with a history lumbar disc prolapse who had undergone lumbar disc surgery on two different occasions was treated using acupuncture, core-stability exercises, and treadmill walking exercises three times per week for 12 weeks. The outcome measures used in this study were pain intensity, spinal range of movement, and general health. After 12 weeks of treatment, the patient had made improvement in terms of pain, which was reduced from 9/10 to 1/10. In a similar vein, the patient's general health showed improvement of >100% after 12 weeks of treatment. Pre-treatment scores of spinal flexion and left-side flexion, which measured 20 cm and 12 cm, respectively, increased to 25 cm and 16 cm after 12 weeks of treatment. This study showed that acupuncture, core-stability exercises, and treadmill walking exercises were useful in relieving pain, increasing spinal range of movement, and improving the health of a patient with postsurgical lumbar disc herniation. PMID:25660445

Ganiyu, Sokunbi Oluwaleke; Gujba, Kachalla Fatimah

2015-02-01

75

Comparative analysis of serum proteomes: Identification of proteins associated with sciatica due to lumbar intervertebral disc herniation  

PubMed Central

Lumbar intervertebral disc herniation (LDH) is one of the most common orthopedic conditions that can cause lower back pain and sciatica. However, the pathogenesis of LDH is poorly understood. The aim of the present study was to use proteomic analysis of blood samples to establish whether there are serum proteins associated with LDH, which may be useful in elucidating LDH pathogenesis. The ultimate aim was to develop a simple technique for the diagnosis of LDH based on the blood samples of patients with sciatica. The study used comparative analysis of serum proteomes associated with sciatica due to LDH. A total of 30 LDH patients with sciatica, receiving treatment between August and December 2007, were selected as the experimental group (or LDH group). A total of 2 ml of blood was obtained from each of the 30 patients in the LDH group and from 30 healthy volunteers, who constituted the control group. Two-dimensional electrophoresis of the blood samples was conducted, distinct protein spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and proteins associated with LDH were detected. An enzyme-linked immunosorbent assay (ELISA) was developed to screen for the LDH proteins and was tested on the sera of a second test and control group that included 10 patients with LDH and 10 healthy subjects, respectively. Based on signal intensity, the expression levels of 6 proteins on the dielectrophoretogram were found to be significantly associated with LDH. The identities of the LDH proteins were upregulated apolipoprotein-L1 (APO-L1) and two types of serum albumin precursors, and downregulated apolipoprotein M (APO-M), tetranectin (TN) and immunoglobulin light chain (IGL). Further ELISA experiments confirmed that there were increased serum levels of 4 out of the 6 proteins in patients with sciatica due to LDH, which was statistically different compared to the healthy subjects. In conclusion, these results suggest that serum APO-L1, TN, APO-M and IGL may serve as LDH biomarkers. PMID:25054013

XIE, PEIGEN; LIU, BIN; CHEN, RUIQIANG; YANG, BU; DONG, JIANWEN; RONG, LIMIN

2014-01-01

76

The Effects of Stretching with Lumbar Traction on VAS and Oswestry Scales of Patients with Lumbar 4–5 Herniated Intervertebral Disc  

PubMed Central

[Purpose] This study investigated the effect of stretching with lumbar traction on VAS and Oswestry scale scores of lumbar 4–5 herniated intervertebral disc (HIVD) patients. [Subjects] We recruited 20 lumbar 4–5 HIVD patients. [Methods] We performed stretching with lumbar traction for lumbar 4–5 HIVD patients during 4 weeks. The VAS and Oswestry scales were measured before and 4 weeks after the intervention. [Results] The results showed a significant decrease in VAS scale scores for stretching with lumbar traction in lumbar 4–5 HIVD patients, from 18±1.29 to 2.1±1.35. The Oswestry scale scores also decreased significantly, from 20.35±2.01 to 3.5±2.84, after stretching with lumbar traction. [Conclusion] Thus, we suggest stretching with lumbar traction for lumbar 4–5 HIVD patients. PMID:25140094

Yang, Hae-sun; Yoo, Won-gyu

2014-01-01

77

Minimally invasive surgery with spotlight work channel system in the treatment of lumbar disc herniation: a retrospective study of 21 cases.  

PubMed

A group of lumbar discherniation cases was treated with posterior discectomy and decompression with Spotlight working channel. We retrospectively studied these patients. To study and analyze the clinical efficacy and technical features of discectomy which is carried out with the Spotlight channel technology. The development of the minimally invasive spine surgery technology promotes new instruments and materials. For minimally invasive spine surgery in channel technology, the newly launched DepuySpine working channel-Spotlight, which is a new generation of wide viewing angle, single-hole device for minimally invasive spine operations, has good prospects for clinical application. From March 2011 to March 2012, 21 patients who were diagnosed with lumbar disc herniation were treated with posterior discectomy and decompression with Spotlight working channel, then the lumbar and leg pain visual analogue scale (VAS) scores of before and after surgery and that of the follow-ups and the Oswestry Disability Index were analyzed. All patients were successfully operated, and also they received follow-ups for more than 1 year. The postoperative lumbar and leg pain VAS scores improved significantly compared with the preoperative ones (P < 0.05) and can effectively maintain (P > 0.05). The three time points of lumbar pain VAS were 7.80 ± 0.49, 1.51 ± 0.52 and 1.47 ± 0.59. The leg pain VAS were 7.53 ± 0.50, 1.58 ± 0.58 and 1.49 ± 0.67. During the follow-ups of the cases in this group, no case of disc herniation relapsed. Patients were satisfied with that. The Spotlight channel system is one of the surgical approaches to "minimally invasive spine technology with direct vision". It has a good range of surgical indications. It can be carried out flexibly and used widely, which means it will be easier for the surgeons to master. PMID:25129385

Xu, Haidong; Jia, Fengyu; Liu, Yanbin; Fu, Qiang

2015-01-01

78

Four-year follow-up results of transforaminal lumbar interbody fusion as revision surgery for recurrent lumbar disc herniation after conventional discectomy.  

PubMed

This study investigated the safety, effectiveness, and clinical and radiological outcomes of transforaminal lumbar interbody fusion (TLIF) for recurrent lumbar disc herniation (rLDH) following previous lumbar spine surgery. Seventy-three consecutive patients treated for rLDH between June 2005 and May 2012 were included in the study. The previous surgical procedures included percutaneous discectomy, discectomy with laminotomy, discectomy with unilateral laminectomy, and discectomy with bilateral laminectomy. The level of rLDH was L4-L5 in 51 patients, L5-S1 in 19 patients, and L3-L4 in three patients. All patients underwent reoperation using the TLIF technique. Outcomes were evaluated using the Oswestry disability index (ODI), visual analogue scale (VAS) scores for low back pain and leg pain, and the Japanese Orthopaedic Association (JOA) score, based on the results of physical examinations and questionnaires. The range of motion and disc height index of the operative segment were compared between preoperative and postoperative radiographs. The mean follow-up period was 4.1years. The VAS scores for low back pain and leg pain, ODI, and JOA score improved significantly between the preoperative and final follow-up evaluations. The mean recovery rate of the JOA score was 89.0%. The disc space height and stability at the fused level were significantly improved after surgery. The fusion rate at the final follow-up was 93.2%. There were no major complications. These results indicate that TLIF can be considered an effective, reliable, and safe alternative procedure for the treatment of rLDH. PMID:25443080

Li, Zhonghai; Tang, Jiaguang; Hou, Shuxun; Ren, Dongfeng; Li, Li; Lu, Xiang; Hou, Tiesheng

2015-02-01

79

Surgical versus Non-Operative Treatment for Lumbar Disc Herniation: Eight-Year Results for the Spine Patient Outcomes Research Trial (SPORT)  

PubMed Central

Study Design Concurrent prospective randomized and observational cohort studies. Objective To assess the 8-year outcomes of surgery vs. non-operative care. Summary of Background Data Although randomized trials have demonstrated small short-term differences in favor of surgery, long-term outcomes comparing surgical to non-operative treatment remain controversial. Methods Surgical candidates with imaging-confirmed lumbar intervertebral disc herniation meeting SPORT eligibility criteria enrolled into prospective randomized (501 participants) and observational cohorts (743 participants) at 13 spine clinics in 11 US states. Interventions were standard open discectomy versus usual non-operative care. Main outcome measures were changes from baseline in the SF-36 Bodily Pain (BP) and Physical Function (PF) scales and the modified Oswestry Disability Index (ODI - AAOS/Modems version) assessed at 6 weeks, 3 and 6 months, and annually thereafter. Results Advantages were seen for surgery in intent-to-treat analyses for the randomized cohort for all primary and secondary outcomes other than work status; however, with extensive non-adherence to treatment assignment (49% patients assigned to non-operative therapy receiving surgery versus 60% of patients assigned to surgery) these observed effects were relatively small and not statistically significant for primary outcomes (BP, PF, ODI). Importantly, the overall comparison of secondary outcomes was significantly greater with surgery in the intent-to-treat analysis (sciatica bothersomeness [p > 0.005], satisfaction with symptoms [p > 0.013], and self-rated improvement [p > 0.013]) in long-term follow-up. An as-treated analysis showed clinically meaningful surgical treatment effects for primary outcome measures (mean change Surgery vs. Non-operative; treatment effect; 95% CI): BP (45.3 vs. 34.4; 10.9; 7.7 to 14); PF (42.2 vs. 31.5; 10.6; 7.7 to 13.5) and ODI (?36.2 vs. ?24.8; ?11.2; ?13.6 to ?9.1). Conclusion Carefully selected patients who underwent surgery for a lumbar disc herniation achieved greater improvement than non-operatively treated patients; there was little to no degradation of outcomes in either group (operative and non-operative) from 4 to 8 years. PMID:24153171

Lurie, Jon D.; Tosteson, Tor D.; Tosteson, Anna N. A.; Zhao, Wenyan; Morgan, Tamara S.; Abdu, William A.; Herkowitz, Harry; Weinstein, James N.

2014-01-01

80

H Wave and Spinal Root Potentials in Neuromonitoring of S1 Root Function during Evacuation of Herniated Disc: Preliminary Results  

PubMed Central

Aim To determine the changes in the tibial H reflex and spinal nerve root potentials (SRPs) of the S1 root during posterior discectomy and the effects of surgical manipulation. Methods Tibial H reflex responses (M and H waves) were intermittently recorded from the soleus muscle by surface electrodes during different stages of surgery in 5 patients with S1 radiculopathy. All patients had Achilles reflex preserved bilateraly and no paresis on manual strength testing preoperatively. SRPs were additionally obtained by direct epidural recordings from the surgically exposed S1 root in 2 of them. Results The variations in the amplitude of H wave were minor and reversible upon the cessation of surgical manipulation of the root, but the H reflex was not lost either temporarily or permanently in any of the patients. Prolongation of H wave latency by up to 18% at the end of surgery in comparison with preoperative value was noticed in 4 patients. However, there was increased degree of desynchronization of the SRP in some phases of the spinal root manipulation, such as root mobilization before the disc incision and retraction during the disc evacuation. H waves and SRPs were continuously present during the surgery. Ankle jerks were preserved postoperatively in all 5 patients. Conclusion Unremarkable variations in H wave latency may be followed by increased SRP desynchronization. Monitoring of the epidurally recorded SRPs seems to be more sensitive to surgical manipulations of the spinal nerve root than the tibial H reflex recordings from the soleus muscle. PMID:16625696

Makovec, Matej; Benedi?i?, Mitja; Bošnjak, Roman

2006-01-01

81

Analgesic effects of balanced acupuncture versus body acupuncture in low-back and leg pain patients with lumbar disc herniation, as assessed by resting-state functional magnetic resonance imaging?  

PubMed Central

Balanced acupuncture, a single-acupoint balance therapy, regulates the balance of the cerebral center, and is characterized by exerting quick effects and a short treatment course. A total of 20 low-back and leg pain patients with lumbar disc herniation were treated with balanced acupuncture or body acupuncture. Central mechanisms of varied acupunctures were compared using resting-state functional MRI. Patients from both groups received functional MRI before and after acupuncture. Functional connectivity in brain regions that were strongly associated with the bilateral amygdala was analyzed utilizing AFNI software. Visual analogue scale scores were greater in the balanced acupuncture group compared with the body acupuncture group. Function of the endogenous pain regulation network was enhanced in patients in the balanced acupuncture group, but was not changed in the body acupuncture group. This result indicates that the analgesic effects of body acupuncture do not work through the central nervous system. These data suggest that balanced acupuncture exerts analgesic effects on low-back and leg pain patients with lumbar disc herniation by regulating the function of the endogenous pain regulation network.

Ye, Yongsong; Liu, Bo

2012-01-01

82

Herniated Disk  

MedlinePLUS

... the jelly-like center of the disk to leak, irritating the nearby nerves. This can cause sciatica or back pain. Your doctor will diagnose a herniated disk with a physical exam and, sometimes, imaging tests. With treatment, most people recover. Treatments include rest, ...

83

A Combinatorial Relative Mass Value Evaluation of Endogenous Bioactive Proteins in Three-Dimensional Cultured Nucleus Pulposus Cells of Herniated Intervertebral Discs: Identification of Potential Target Proteins for Gene Therapeutic Approaches  

PubMed Central

Painful degenerative disc diseases have been targeted by different biological treatment approaches. Nucleus pulposus (NP) cells play a central role in intervertebral disc (IVD) maintenance by orchestrating catabolic, anabolic and inflammatory factors that affect the extracellular matrix. IVD degeneration is associated with imbalances of these factors, resulting in a catabolic inflammatory metabolism. Therefore, accurate knowledge about their quantity and quality with regard to matrix synthesis is vital for a rational gene therapeutic approach. NP cells were isolated from 63 patients operated due to lumbar disc herniation (mean age 56 / range 29 - 84 years). Then, three-dimensional culture with low-glucose was completed in a collagen type I scaffold for four weeks. Subsequently cell proliferation evaluation was performed using 3-(4, 5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide and intracellular concentration of 28 endogenously expressed anabolic, catabolic, inflammatory factors and relevant matrix proteins was determined by enzyme-linked immunosorbent assay. Specimen-related grades of degeneration were confirmed by preoperative magnetic resonance imaging. Independent from gender, age and grade of degeneration proliferation rates remained similar in all groups of NP cells. Progressive grades of degeneration, however, showed a significant influence on accumulation of selective groups of factors such as disintegrin and metalloproteinase with thrombospondin motifs 4 and 5, matrix metalloproteinase 3, metalloproteinase inhibitor 1 and 2, interleukin-1? and interleukin-1 receptor. Along with these changes, the key NP matrix proteins aggrecan and collagen II decreased significantly. The concentration of anabolic factors bone morphogenetic proteins 2, 4, 6 and 7, insulin-like growth factor 1, transforming growth factor beta 1 and 3, however, remained below the minimal detectable quantities. These findings indicate that progressive degenerative changes in NP may be problematic with regard to biologic treatment strategies. Hence, gene therapeutic interventions regulating relevant bioactive factors identified in this work might contribute to the development of regenerative treatment approaches for degenerative disc diseases. PMID:24278441

Mern, Demissew S.; Fontana, Johann; Beierfuß, Anja; Thomé, Claudius; Hegewald, Aldemar A.

2013-01-01

84

Quantitative Discomanometry: Correlation of Intradiscal Pressure Values to Pain Reduction in Patients With Intervertebral Disc Herniation Treated With Percutaneous, Minimally Invasive, Image-Guided Techniques  

SciTech Connect

Purpose: To illustrate quantitative discomanometry's (QD) diagnostic efficacy and predictive value in discogenic-pain evaluation in a prospective study correlating intradiscal pressure values with pain reduction after percutaneous image-guided technique (i.e., percutaneous decompression, PD). Materials and Methods: During the last 3 years, 36 patients [21 male and 15 female (mean age 36 {+-} 5.8 years)] with intervertebral disc hernia underwent QD before PD. Under absolute sterilization and fluoroscopy, a mixture of contrast medium and normal saline (3:1 ratio) was injected. A discmonitor performed a constant rate injection and recorded pressure and volume values, thus producing the relative pressure-volume curve. PD was then performed. Pain reduction and improved mobility were recorded at 3, 12, and 24 months after PD using clinical evaluation and a numeric visual scale (NVS; 0 to 10 units). Results: Mean pain values of 7.5 {+-} 1.9 (range 4 to 8) NVS units were recorded before PD; these decreased to 2.9 {+-} 2.44 at 3 months, 1.0 {+-} 1.9 at 12 months, and 1.0 {+-} 1.9 NVS units at 24 months after PD. Recorded correlations (pressure, volume, significant pain-reduction values) with bilateral statistical significance included a maximum injected volume of 2.4 ml (p = 0.045), P{sub o} < 14 psi [initial pressure required to inject 0.1 ml of the mixture inside the disc (p = 0.05)], P{sub max} {<=} 65 psi [greatest pressure value on the curve (p = 0.018)], and P{sub max} - P{sub o} {<=} 47 psi (p = 0.038). Patients meeting these pressure or volume cut-off points, either independently or as a total, had significant pain reduction (>4 NVS units) after PD. No complications were noted. Conclusions: QD is an efficient technique that may have predictive value for discogenic pain evaluation. It might serve as a useful tool for patient selection for intervertebral disc therapies.

Filippiadis, Dimitrios K., E-mail: dfilippiadis@yahoo.gr; Mazioti, A., E-mail: argyromazioti@yahoo.gr; Papakonstantinou, O., E-mail: sogofianol@gmail.com; Brountzos, E., E-mail: ebrountz@med.uoa.gr [University General Hospital 'Attikon', Second Radiology Department (Greece); Gouliamos, A., E-mail: agouliam@med.uoa.gr [University General Hospital 'Areteion', First Radiology Department (Greece); Kelekis, N., E-mail: kelnik@med.uoa.gr; Kelekis, A., E-mail: akelekis@med.uoa.gr [University General Hospital 'Attikon', Second Radiology Department (Greece)

2012-10-15

85

Senescence in human intervertebral discs  

Microsoft Academic Search

Intervertebral discs demonstrate degenerative changes relatively early in life. Disc degeneration, in turn, is associated\\u000a with back pain and disc herniation, both of which cause considerable clinical problems in the western world. Cell senescence\\u000a has been linked to degenerative diseases of other connective tissues such as osteoarthritis. Thus we investigated the degree\\u000a of cell senescence in different regions of discs

S. Roberts; E. H. Evans; D. Kletsas; D. C. Jaffray; S. M. Eisenstein

2006-01-01

86

Advances in Susceptibility Genetics of Intervertebral Degenerative Disc Disease  

PubMed Central

The traditional view that the etiology of lumbar disc herniation is primarily due to age, gender, occupation, smoking and exposure to vehicular vibration dominated much of the last century. Recent research indicates that heredity may be largely responsible for the degeneration as well as herniation of intervertebral discs. Since 1998, genetic influences have been confirmed by the identification of several genes forms associated with disc degeneration. These researches are paving the way for a better understanding of the biologic mechanisms. Now, many researchers unanimously agree that lumbar disc herniation appears to be similar to other complex diseases, whose etiology has both environmental and hereditary influence, each with a part of contribution and relative risk. Then addressing the etiological of lumbar disc herniation, it is important to integrate heredity with the environment factors. For the purpose of this review, we have limited our discussion to several susceptibility genes associated with disc degeneration. PMID:18781226

Zhang, Yin'gang; Sun, Zhengming; Liu, Jiangtao; Guo, Xiong

2008-01-01

87

Asymptomatic Transhiatal Pancreatic Herniation after Oesophagectomy  

PubMed Central

Transhiatal herniation of abdominal organs after oesophageal resection and reconstruction is rare and sparsely described in the literature. The commonest organ to herniate is the colon. Pancreatic herniation has been reported twice before. We report a case of postoesophagectomy transhiatal pancreatic herniation in an asymptomatic patient. PMID:25478403

Pal, Sujoy; Dash, Nihar Ranjan; Madhusudhan, KS; Srivastava, Deep Narayan

2014-01-01

88

Intramuscular Oxygen-Ozone Therapy in the Treatment of Acute Back Pain With Lumbar Disc Herniation A Multicenter, Randomized, Double-Blind, Clinical Trial of Active and Simulated Lumbar Paravertebral Injection  

Microsoft Academic Search

Study Design. Multicenter randomized, double-blind, simulated therapy-controlled trial in a cohort of patients with acute low back pain (LBP) due to lumbar disc herni- ation (LDH). Objective. To assess the benefit of intramuscular-para- vertebral injections of an oxygen-ozone (O2O3) mixture. Summary of Background Data. Recent findings have shown that O2O3 therapy can be used to treat LDH that fails to

Marco Paoloni; Angelo Cacchio; Dario Apuzzo; Salvatore Marotta; Michele Razzano; Marianno Franzini; Valter Santilli

89

Intradural disc mimicking: a spinal tumor lesion  

Microsoft Academic Search

Study design: A case report of intradural disc hernia mimicking an intradural extramedullary spinal tumor lesion in radiological evaluation.Objective: To describe a lumbar intradural disc herniation with atypical radiological appearance and point out the role of contrast magnetic resonance imaging (MRI) of the lumbar spine.Setting: Turkey.Case report: A 58-year-old man with suspected lumbar intradural mass and neurological involvement received L5

M V Aydin; S Ozel; O Sen; B Erdogan; T Yildirim

2004-01-01

90

Paraduodenal herniation: An internal herniation in a virgin abdomen  

PubMed Central

INTRODUCTION A paraduodenal hernia is an uncommon hernia that results from an abnormal rotation of the midgut. Commonly, these hernias are congenital in nature, and are reported to cause 1.5–5.8% of intestinal obstructions. These hernias occur when a part of the jejunum herniates through the posterior portion of the ligament of Treitz. Diagnosing these hernias preoperatively has been shown to be difficult, despite the studies that are available. Early diagnosis is imperative to the patient in order to avoid strangulation of the bowel, which is associated with a high mortality. PRESENTATION OF CASE In this case, we present a case of a left-sided paraduodenal hernia in a virgin abdomen in a 38-year-old African American male with a herniation of a loop of jejunum through a defect of the posterior portion of the ligament of Treitz. The patient also had a volvulized segment of the proximal jejunum, and part of this bowel was found to be ischemic. DISCUSSION Acute intestinal obstruction caused by a left paraduodenal hernia is a rare cause of intestinal obstruction. A literary search of PubMed between 1980 and 2012 indicated only 44 cases of intestinal obstruction secondary to a left paraduodenal hernia. CONCLUSION The patient underwent exploratory laparotomy, and the herniated bowel was found to be ischemic. The hernia was reduced, and the ischemic bowel resected. The defect was closed, and the patient had a non-complicated recovery. PMID:25437660

Kabbani, Dana; Salem, Ayman; Holloway, Daniel K.

2014-01-01

91

Higher risk of dural tears and recurrent herniation with lumbar micro-endoscopic discectomy  

Microsoft Academic Search

Existing studies on micro-endoscopic lumbar discectomy report similar outcomes to those of open and microdiscectomy and conflicting\\u000a results on complications. We designed a randomised controlled trial to investigate the hypothesis of different outcomes and\\u000a complications obtainable with the three techniques. 240 patients aged 18–65 years affected by posterior lumbar disc herniation\\u000a and symptoms lasting over 6 weeks of conservative management were randomised

Marco Teli; Alessio Lovi; Marco Brayda-Bruno; Antonino Zagra; Andrea Corriero; Fabrizio Giudici; Leone Minoia

2010-01-01

92

Enhancement of KTP\\/532 laser disc decompression and arthroscopic microdiscectomy with a vital dye  

Microsoft Academic Search

Currently, the clinical indications and results of arthroscopic microdiscectomy and laser disc decompression come close to, but do not exceed, the results of classic discectomy or microdiscectomy for the whole spectrum of surgical disc herniations. However, as minimally invasive techniques continue to evolve, results can be expected to equal or be potentially superior to conventional surgery. This exhibit demonstrates how

Anthony T. Yeung

1993-01-01

93

[A case of paraesophageal omental herniation].  

PubMed

A 48-year-old woman underwent routine chest roentgenography and a mass shadow was seen in the posterior mediastinum. CT, MRI and celiac arteriography were performed, and paraesophageal omental herniation was diagnosed. Paraesophageal omental herniation is uncommon, and there have been no reports cases with complications. Therefore, this case is being followed-up carefully. PMID:9611979

Saijo, Y; Honda, H; Nishigaki, Y; Noro, T

1998-01-01

94

Osteopoikilosis mimicking lumbar disc herniation: a case report  

Microsoft Academic Search

It is important for the chiropractor to be able to determine the nature of the pathology discovered on plain film radiography, and to suggest appropriate follow-up investigations, deemed to be clinically appropriate. This case demonstrates the value of plain-film radiography in diagnosing a rare sclerosing bone dysplasia, which in 10–15% of affected individuals is associated with articular pain and swelling.

Michelle Wessely

2000-01-01

95

Tissue-engineered intervertebral discs produce new matrix, maintain disc height, and restore biomechanical function to the rodent spine  

Microsoft Academic Search

Lower back and neck pain are leading physical conditions for which patients see their doctors in the United States. The organ commonly implicated in this condition is the intervertebral disc (IVD), which frequently herniates, ruptures, or tears, often causing pain and limiting spinal mobility. To date, approaches for replacement of diseased IVD have been confined to purely mechanical devices designed

Robby D. Bowles; Harry H. Gebhard; Roger Härtl; Lawrence J. Bonassar

2011-01-01

96

Percutaneous diode laser disc nucleoplasty  

NASA Astrophysics Data System (ADS)

The treatment of herniated disc disease (HNP) over the years involved different miniinvasive surgical options. The classical microsurgical approach has been substituted over the years both by endoscopic approach in which is possible to practice via endoscopy a laser thermo-discoplasty, both by percutaneous laser disc nucleoplasty. In the last ten years, the percutaneous laser disc nucleoplasty have been done worldwide in more than 40000 cases of HNP. Because water is the major component of the intervertebral disc, and in HNP pain is caused by the disc protrusion pressing against the nerve root, a 980 nm Diode laser introduced via a 22G needle under X-ray guidance and local anesthesia, vaporizes a small amount of nucleous polposus with a disc shrinkage and a relief of pressure on nerve root. Most patients get off the table pain free and are back to work in 5 to 7 days. Material and method: to date, 130 patients (155 cases) suffering for relevant symptoms therapy-resistant 6 months on average before consulting our department, have been treated. Eightyfour (72%) males and 46 (28%) females had a percutaneous laser disc nucleoplasty. The average age of patients operated was 48 years (22 - 69). The level of disc removal was L3/L4 in 12 cases, L4/L5 in 87 cases and L5/S1 in 56 cases. Two different levels were treated at the same time in 25 patients. Results: the success rate at a minimum follow-up of 6 months was 88% with a complication rate of 0.5%.

Menchetti, P. P.; Longo, Leonardo

2004-09-01

97

Case report: The operation for the lumbar disk herniation just after cesarean delivery in the third trimester of pregnancy  

PubMed Central

INTRODUCTION Low back pain is common during pregnancy. However, the incidence of symptomatic lumbar disc herniation during pregnancy is very rare. We report a case of lumbar disc herniation underwent discectomy just after cesarean delivery in the third trimester of pregnancy. PRESENTATION OF CASE A 33-year-old woman presented at 32 weeks gestation. She had a low back pain and the left-sided leg pain below the knee. At 34 weeks gestation, she had severe weakness of the left extension halluces longus, left ankle dorsiflexion. MRI showed a large disc herniation at L4/5 expanded to the spinal canal more. The cesarean delivery was performed in the supine position. The patient was then turned to a prone position, and a left L4/5 discectomy was performed. But the day after surgery, she had a severe low back pain and the right leg pain below the knee. MRI showed a disc herniation at L4/5 on the right side of the spinal canal. At 6 days after the first surgery, a right L4/5 discectomy was performed. In the immediate postoperative period, the patient experienced complete relief of the right leg pain. DISCUSSION It is necessary to cooperate with a pediatrician, an obstetrician, and an anethesiologists. For obtaining the best outcome on mother and child, it is important to discuss in advance to be able to respond quickly for changeable situation. CONCLUSION It is necessary to conduct the operation under pregnancy in consideration of the great influence on mother and child. PMID:25437670

Ochi, Hironori; Ohno, Ryuichi; Kubota, Mitsuaki; Hanyu, Ryo; Sakai, Kensuke; Sugawara, Yu; Mukasa, Fumihiro; Kaneko, Kazuo

2014-01-01

98

Deuk Laser Disc Repair® is a safe and effective treatment for symptomatic cervical disc disease  

PubMed Central

Background: Deuk Laser Disc Repair® is a new full-endoscopic surgical procedure to repair symptomatic cervical disc disease. Methods: A prospective cohort of 66 consecutive patients underwent cervical Deuk Laser Disc Repair® for one (n = 21) or two adjacent (n = 45) symptomatic levels of cervical disc disease and were evaluated postoperatively for resolution of headache, neck pain, arm pain, and radicular symptoms. All patients were candidates for anterior cervical discectomy and fusion (ACDF) or arthroplasty. The Mann–Whitney Wilcoxon test was used to calculate P values. Results: All patients (n = 66) had significant improvement in preoperative symptoms with an average symptom resolution of 94.6%. Fifty percent (n = 33) had 100% resolution of all preoperative cervicogenic symptoms. Only 4.5% (n = 3) had less than 80% resolution of preoperative symptoms. Visual analog scale (VAS) significantly improved from 8.7 preoperatively to 0.5 postoperatively (P < 0.001) for the cohort. Average operative and recovery times were 57 and 52 minutes, respectively. There were no perioperative complications. Recurrent disc herniation occurred in one patient (1.5%). Average postoperative follow-up was 94 days and no significant intergroup difference in outcomes was observed (P = 0.111) in patients with <90 days (n = 52) or >90 days (n = 14, mean 319 days) follow-up. No significant difference in outcomes was observed (P = 0.774) for patients undergoing one or two level Deuk Laser Disc Repair®. Patients diagnosed with postoperative cervical facet syndrome did significantly worse (P < 0.001). Conclusion: Deuk Laser Disc Repair® is a safe and effective alternative to ACDF or arthroplasty for the treatment of one or two adjacent symptomatic cervical disc herniations with an overall success rate of 94.6%. PMID:23776754

Deukmedjian, Ara J.; Jason Cutright, S. T.; Augusto Cianciabella, PA-C; Deukmedjian, Arias

2013-01-01

99

Herniated pancreatic body within a paraesophageal hernia  

PubMed Central

A hiatal hernia can be classified as one of four types according to the position of the gastroesophageal (GE) junction and the extent of herniated stomach. Type I, or sliding hernias, account for up to 95% of all hiatal hernias and occur when the GE junction migrates into the posterior mediastinum through the hiatus. Type II occurs when the fundus herniates through the hiatus alongside a normally positioned GE junction. Type III is a combination of types I and II hernias with a displaced GE junction as well as stomach protruding through the hiatus. Type IV paraesophageal hernias are the rarest of the hiatal hernias. Usually, colon or small bowel is herniated within the mediastinum along with the stomach. We present a case of a paraesophageal hernia with the mid-body of the pancreas as part of the hernia contents. PMID:21394323

Coughlin, Megan; Fanous, Medhat; Velanovich, Vic

2011-01-01

100

Topographical guidance of intervertebral disc cell growth in vitro: towards the development of tissue repair strategies for the anulus fibrosus  

Microsoft Academic Search

The anulus fibrosus (AF) of the intervertebral disc consists of concentric sheets of collagenous matrix that is synthesised\\u000a during embryogenesis by aligned disc cells. This highly organised structure may be severely disrupted during disc degeneration\\u000a and\\/or herniation. Cell scaffolds that incorporate topographical cues as contact guidance have been used successfully to promote\\u000a the healing of injured tendons. Therefore, we have

William E. Johnson; Andrew Wootton; Alicia El Haj; Stephen M. Eisenstein; Adam S. Curtis; Sally Roberts

2006-01-01

101

Accretion discs  

NASA Astrophysics Data System (ADS)

Accretion discs are flattened astronomical objects made of rapidly rotating gas which slowly spirals onto a central gravitating body. The gravitational energy of infalling matter extracted in accretion discs powers stellar binaries, active galactic nuclei, proto-planetary discs and some gamma-ray bursts. The black hole accretion in quasars is the most powerful and efficient stationary engine known in the universe. In accretion discs the high angular momentum of rotating matter is gradually transported outwards by stresses (related to turbulence, viscosity, shear and magnetic fields). This gradual loss of angular momentum allows matter to progressively move inwards, towards the centre of gravity. The gravitational energy of the gaseous matter is thereby converted to heat. A fraction of the heat is converted into radiation, which partially escapes and cools down the accretion disc. Accretion disc physics is thus governed by a non-linear combination of many processes, includ! ing gravity, hydrodynamics, viscosity, radiation and magnetic fields.

Abramowicz, Marek A.; Straub, Odele

2014-08-01

102

Annulo-nucleoplasty using Disc-FX in the management of lumbar disc pathology: Early results  

PubMed Central

Background Back pain due to Lumbar Disc Disease is a major clinical problem. The treatment options range from physiotherapy to fusion surgery. A number of minimally invasive procedures have also been developed in the recent past for its management. Disc-FX is a new minimally invasive technique that combines percutaneous discectomy, nuclear ablation and annular modification. Literature on its role in the management of lumbar disc pathology is scarce. Methods We included 24 consecutive patients who underwent the Disc-FX for back pain due to lumbar disc pathology non-responsive to non-operative treatment for a period of at least 6 months. Based on Magnetic Resonance Imaging (MRI) these patients fell into 2 groups – those with degenerative disc disease (DDD) (n = 12) and those with a contained lumbar disc herniation (CLDH)(n = 12). They were evaluated using the Visual analogue scale (VAS), Oswestry Disability Index (ODI) and Short Form-36 (SF-36) scores preoperatively and postoperatively. Results The mean age was 37.9 years (21-53 years). There were 17 males and 7 females. One patient in each subgroup was excluded from the final evaluation. Significant improvement was seen in all outcome measures. The overall rate of reintervention for persistent symptoms was 18.18% (4/22); in the CLDH subgroup, it was 36.36% (4/11). Conclusions and level of evidence Early results after the Disc-FX procedure suggest that it s a reasonable treatment option for patients with back pain due to lumbar disc disease, especially for those with DDD who fail conservative treatment. It could be an alternative to procedures like fusion or disc replacement. This study presents Level IV evidence. Clinical relevance We feel that our study establishes Disc-FX as a modality of treating symptomatic lumbar disc disease due to DDD. However, longer term prospective studies are needed to prove this and to evaluate its role in the treatment of patients with CLDH.

Kumar, Aravind; Siddharth M, Shah; Sambhav P, Shah; Tan, Justin

2014-01-01

103

Lifestyle factors and lumbar disc disease: results of a German multi-center case-control study (EPILIFT)  

PubMed Central

Introduction In the large-scale case-control study EPILIFT, we investigated the dose-response relationship between lifestyle factors (weight, smoking amount, cumulative duration of different sports activities) and lumbar disc disease. Methods In four German study regions (Frankfurt am Main, Freiburg, Halle/Saale, Regensburg), 564 male and female patients with lumbar disc herniation and 351 patients with lumbar disc narrowing (chondrosis) aged 25 to 70 years were prospectively recruited. From the regional population registers, 901 population control subjects were randomly selected. In a structured personal interview, we enquired as to body weight at different ages, body height, cumulative smoking amount and cumulative duration of different sports activities. Confounders were selected according to biological plausibility and to the change-in-estimate criterion. Adjusted, gender-stratified odds ratios with 95% confidence intervals were calculated using unconditional logistic regression analysis. Results The results of this case-control study reveal a positive association between weight and lumbar disc herniation as well as lumbar disc narrowing among men and women. A medium amount of pack-years was associated with lumbar disc herniation and narrowing in men and women. A non-significantly lowered risk of lumbar disc disease was found in men with high levels of cumulative body building and strength training. Conclusions According to our multi-center case-control study, body weight might be related to lumbar disc herniation as well as to lumbar disc narrowing. Further research should clarify the potential protective role of body building or strength training on lumbar disc disease. PMID:20955546

2010-01-01

104

Herniation through the foramen of Winslow presenting as obstructive jaundice.  

PubMed

Herniation through the foramen of Winslow is a rare variety of paraduodenal hernia. We report a 19-month-old child with obstructive jaundice due to midgut herniation through the foramen of Winslow with associated volvulus. The herniation and volvulus were precipitated by intestinal malrotation. The patient underwent extraamniotic silo repair of exomphalos major in the neonatal period. Investigation for malrotation is recommended after extraamniotic closure of exomphalos. PMID:15902477

Antao, B; Hamill, J; Samuel, M; Hiorns, M; Pierro, A

2005-07-01

105

Cecal bascule herniation into the lesser sac  

PubMed Central

Cecal bascule is a rare cause of bowel obstruction in which a mobile cecum folds anteriorly and superiorly over the ascending colon. Herein, we present the first case of internal herniation of a cecal bascule into the lesser sac through the foramen of winslow, aiming at discussing radiological findings, differential diagnosis, and surgical management of this uncommon condition. A 75-year-old female presented to the emergency room with an 18-h history of sudden onset sharp, progressively worsening abdominal pain associated with vomiting. Physical exam revealed abdominal distention and epigastric tenderness while initial laboratory tests were unremarkable. Computed tomography of her abdomen and pelvis showed a loop of distended colon within lesser sac without signs of bowel ischemia or perforation. On exploratory laparotomy, a cecal bascule was found herniating into lesser sac via foramen of winslow. Upon reduction, the cecum appeared viable therefore a cecopexy was performed without bowel resection. Unlike cecal volvulus, cecal bascule consists of no axial rotation of the bowel with no mesenteric vascular compromise and therefore ischemia would only occur from intraluminal tension or extraluminal compression from the borders of foramen of winslow. The management of internal herniation of a cecal bascule is always surgical including anatomic resection or cecopexy. PMID:25516868

Makarawo, Tafadzwa; Macedo, Francisco Igor; Jacobs, Michael J

2014-01-01

106

Cecal bascule herniation into the lesser sac.  

PubMed

Cecal bascule is a rare cause of bowel obstruction in which a mobile cecum folds anteriorly and superiorly over the ascending colon. Herein, we present the first case of internal herniation of a cecal bascule into the lesser sac through the foramen of winslow, aiming at discussing radiological findings, differential diagnosis, and surgical management of this uncommon condition. A 75-year-old female presented to the emergency room with an 18-h history of sudden onset sharp, progressively worsening abdominal pain associated with vomiting. Physical exam revealed abdominal distention and epigastric tenderness while initial laboratory tests were unremarkable. Computed tomography of her abdomen and pelvis showed a loop of distended colon within lesser sac without signs of bowel ischemia or perforation. On exploratory laparotomy, a cecal bascule was found herniating into lesser sac via foramen of winslow. Upon reduction, the cecum appeared viable therefore a cecopexy was performed without bowel resection. Unlike cecal volvulus, cecal bascule consists of no axial rotation of the bowel with no mesenteric vascular compromise and therefore ischemia would only occur from intraluminal tension or extraluminal compression from the borders of foramen of winslow. The management of internal herniation of a cecal bascule is always surgical including anatomic resection or cecopexy. PMID:25516868

Makarawo, Tafadzwa; Macedo, Francisco Igor; Jacobs, Michael J

2014-12-16

107

DETAIL OF DENVER DISC FILTER IN CO91107, SUCTION END. NOTE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL OF DENVER DISC FILTER IN CO-91-107, SUCTION END. NOTE BEARING HOUSING WITH CAST LOGO, SUCTION PIPE GOING OFF TO THE RIGHT, AND FILTER DISC IN BACKGROUND. VACUUM INSIDE DISCS FURTHER DEWATERED CONCENTRATE. AS DISC SLOWLY ROTATED A BAR SCRAPED DRIED CONCENTRATE FROM OUTSIDE OF FILTER CLOTH. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

108

Effect of microgravity on the biomechanical properties of lumbar and caudal intervertebral discs in mice.  

PubMed

Prolonged exposure to microgravity has shown to have deleterious effects on the human spine, indicated by low back pain during spaceflight and increased incidence of post-spaceflight herniated nucleus pulposus. We examined the effect of microgravity on biomechanical properties of lumbar and caudal discs from mice having been on 15-day shuttle mission STS-131. Sixteen C57BL/C mice (spaceflight group, n=8; ground-based control group, n=8) were sacrificed immediately after spaceflight. Physiological disc height (PDH) was measured in situ, and compressive creep tests were performed to parameterize biomechanical properties into endplate permeability (k), nuclear swelling pressure strain dependence (D), and annular viscoelasticity (G). For caudal discs, the spaceflight group exhibited 32% lower PDH, 70% lower D and crept more compared to the control mice (p=0.03). For lumbar discs, neither PDH nor D was significantly different between murine groups. Initial modulus, osmotic pressure, k and G for lumbar and caudal discs did not appear influenced by microgravity (p>0.05). Decreases in both PDH and D suggest prolonged microgravity effectively diminished biomechanical properties of caudal discs. By contrast, differences were not noted for lumbar discs. This potentially deleterious interaction between prolonged weightlessness and differential ranges of motion along the spine may underlie the increased cervical versus lumbar disc herniation rates observed among astronauts. PMID:25085756

Bailey, Jeannie F; Hargens, Alan R; Cheng, Kevin K; Lotz, Jeffrey C

2014-09-22

109

Inguinal herniation of the bladder in an infant.  

PubMed

Inguinal herniation of the bladder is an uncommon finding with fewer than 200 cases reported in the literature. It is found most commonly in older, obese men with lower urinary tract symptoms. We report a case of inguinal herniation of the bladder in a premature infant. PMID:16672120

Manatt, Scott; Campbell, Jeffrey B; Ramji, Faridali; Kuhn, Ann; Frimberger, Dominic

2006-04-01

110

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

SciTech Connect

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

Kelekis, Alexis D., E-mail: akelekis@med.uoa.gr; Filippiadis, Dimitris K., E-mail: dfilippiadis@yahoo.g [Attikon University Hospital, 2nd Radiology Department (Greece); Martin, Jean-Baptiste, E-mail: jbmartin@cird.c [Geneva University Hospital, Service d'Imagerie Medicale (Switzerland); Brountzos, Elias, E-mail: ebrountz@med.uoa.g [Attikon University Hospital, 2nd Radiology Department (Greece)

2010-10-15

111

Ambulatory surgery is safe and effective in radicular disc disease.  

PubMed

Advances in medicine, including diagnostic techniques and therapeutic procedures, have resulted in the ambulatory management of many diseases. A number of surgical procedures previously considered to require hospitalization now are offered on a routine basis as an outpatient or short-stay admission. Although the use of microdiscectomy for the treatment of virgin herniated disc in ambulatory patients has been reported in very limited numbers, it has not been applied to other problems, such as recurrent herniated disc, far lateral disc, or foramenal stenosis. In addition, it only has been used in optimal patients. The authors analyzed a diverse group of patients who underwent outpatient microdiscectomy and found, for most patients studied, hospitalization was not necessary. Seventy-four patients were prospectively studied to determine whether unilateral root decompression for disc or stenosis could be accomplished on an ambulatory basis. Ninety percent of the patients were able to be discharged on the day of surgery. There was no significant morbidity related to the ambulatory approach. The authors also found a significant cost savings for third party reimbursers. PMID:8184345

Bookwalter, J W; Busch, M D; Nicely, D

1994-03-01

112

Compared with the Conventional MR Imaging, Do the Constructive Interference Steady State Sequence and Diffusion Weighted Imaging Aid in the Diagnosis of Lumbar Disc Hernias?  

PubMed Central

Objective: Our aim was to evaluate the efficacy of Diffusion Weighted Imaging (DWI) and Constructive Interference Steady State (CISS) sequences in the depiction of lumbar disc hernias, including sequestrated and extruded discs. Materials and Methods: 100 patients; 35 males and 65 females, with 3 sequestration-16 extruded and 81 protruded all together 100 herniated discs were involved in this study. If a patient had more than one herniated disc, then the more precise herniation was included. All the MRI procedures were handled in Siemens Symphony Power 1.5 T. magnet. DWI- Apparent diffusion coefficient (ADC mapping) and CISS sequences were obtained in axial planes. Statistical analysis of CISS and DWI results were analysed by fischer’s test, chi square statistics. Results: CISS sequence had a 89% sensitivity, 100% specificity for all lumbar disc hernias, had 100% sensitivity and specificity in the evaluation of sequestrated and extruded discs. DWI had a 77% sensitivity and %100 specificity, had 100% sensitivity and 50% specificity in the evaluation of extrusion, 100% sensitivity and specificity in the evaluation of sequestration. Conclusion: CISS sequence and quantitative DWI may be alternative imaging modalities to the routine MR imaging sequences in the depiction of lumbar disc hernias, including sequestration and extruded discs.

Aydin, Hasan; Kizilgoz, Volkan; Hekimoglu, Baki

2011-01-01

113

Migratory intradural disk herniation and a strategy for intraoperative localization.  

PubMed

Study Design?Case report. Objective?Describe a case of intradural disk herniation and a method for intraoperative localization. Methods?Intradural disk herniations are uncommon but well described. The diagnosis of these lesions is often difficult, and sometimes they may be diagnosed only through an intradural exploration after an expected disk fragment cannot be located. We report the case of an intradural disk herniation with an additional diagnostic difficulty-a migrated intradural disk. Results?We present the first intraoperative imaging evidence of disk migration and propose a strategy to locate intradural disk fragments prior to durotomy. Conclusion?Intradural disk herniations should be suspected when intraoperative findings are not congruent with imaging findings. An intraoperative myelogram may be helpful. PMID:25648315

Daffner, Scott D; Sedney, Cara L; Rosen, Charles L

2015-02-01

114

Intrathoracic omental herniation through the esophageal hiatus: a case report.  

PubMed

A case of paraesophageal omental herniation in a 74-year-old man is reported. Although computed tomography (CT) and magnetic resonance imaging (MRI) depicted a retrocardiac fatty mass that resembled omental herniation, residual concern remained regarding lipomatous tumor. Angiography provided decisive evidence of a mass containing omental vessels passing through the esophageal hiatus, which led to the final diagnosis. The patient underwent a strict course of observation, because he had no symptoms or abnormal physical or laboratory findings. Paraesophageal omental herniation mimics lipomatous tumors, such as lipoma or well-differentiated liposarcoma, extending to both sides of the diaphragm. Correct diagnosis of omental herniation requires the evidence of omental fat accompanied with omental vessels passing through the esophageal hiatus. Since angiography is an invasive diagnostic procedure, we would recommend dynamic MRI or reconstructed 3D MR angiography as alternatives to angiography. PMID:11837582

Kubota, K; Ohara, S; Yoshida, S; Nonami, Y; Takahashi, T

2001-01-01

115

Inguinal herniation with hydrometra/mucometra in a poodle bitch.  

PubMed

A 5-year-old, sexually intact poodle bitch was presented with a 2-year history of inguinal mass. A tentative diagnosis of hydrometra/mucometra with inguinal herniation was made and ovariohysterectomy with hernia repair was performed. Both fluid-filled uterine horns, both broad ligaments, and the uterine body were observed to be herniated through the inguinal ring. On histopathology, marked edema and diffuse hemorrhage were diagnosed in the uterus. PMID:24155486

Sontas, B Hasan; Toydemir, F T Seval; Erdogan, Ozge; Sennazli, Gülbin; Ekici, Hayri

2013-09-01

116

Inguinal herniation with hydrometra/mucometra in a poodle bitch  

PubMed Central

A 5-year-old, sexually intact poodle bitch was presented with a 2-year history of inguinal mass. A tentative diagnosis of hydrometra/mucometra with inguinal herniation was made and ovariohysterectomy with hernia repair was performed. Both fluid-filled uterine horns, both broad ligaments, and the uterine body were observed to be herniated through the inguinal ring. On histopathology, marked edema and diffuse hemorrhage were diagnosed in the uterus. PMID:24155486

Sontas, B. Hasan; Toydemir, F.T. Seval; Erdogan, Özge; ?ennazli, Gülbin; Ekici, Hayri

2013-01-01

117

Idiopathic brain herniation. A report of two paediatric cases.  

PubMed

SUMMARY - 'Idiopathic' herniation of the brain is a rare entity previously reported in 13 cases. It may be incidentally encountered in neuroimaging studies acquired for various clinical indications. We herein describe two cases of idiopathic brain herniation that were incidentally diagnosed. A 12-year-old boy presented with a six-month history of daytime sleepiness and sudden spells of sleep. Herniation of the left inferior temporal gyrus was revealed in MRI acquired with the suspicion of epilepsy. His overnight polysomnogram and multiple sleep latency tests were compatible with the diagnosis of narcolepsy. The other case, a two-year-old girl, was transferred from an outside hospital due to partial seizures with the fever. Herniation of the precuneal gyrus was encountered in MRI acquired after controlling her seizures with the initiation of phenytoin. The brain herniations of both patients were considered to be inconsistent with their medical conditions, so that they were symptom-free with only medical treatment for following three and six months, respectively. This is a rare presentation of idiopathic brain herniation as an incidental finding that accompanied narcolepsy and epilepsy. Awareness of this entity would avoid excessive surgical and medical treatments. PMID:25260205

Koc, Gonca; Doganay, Selim; Bayram, Ayse Kacar; Gorkem, Sureyya Burcu; Dogan, Mehmet Sait; Per, Huseyin; Coskun, Abdulhakim

2014-10-01

118

D-Zero Cryostat Supplemental Rupture Disc  

SciTech Connect

The common relief and rupture disc vent line requires a double disc assembly with vented interspace for accurate disc burst pressures. The first disc must take pump and purge vacuum loading, but be set to operate at 110% of the MAWP, 18.3 psig (ASME code). The available solution is 18.3 psig with a burst tolerance of +/- psig. The interspace should be locally vented by a flow limiting vent valve to decouple the vent line backpressure from the vessel rupture disc. The second disc must take the worst case vent line backpressure, the steady state value found in D-Zero engineering note 3740.000-EN-63 with all three cryostats simultaneously venting at the fire condition into the 4-inch x 6-inch and 6-inch x 8-inch sections. This value is less than 2 psid. The maximum rupture value for the second disc must be less than the minimum rupture value for the first disc less 2 psid i.e. < 16.3.

Mulholland, G.T.; /Fermilab

1987-08-03

119

Intervertebral Disc Engineering through Exploiting Mesenchymal Stem Cells: Progress and Perspective.  

PubMed

Intervertebral disc degeneration is a common spinal disorder and may manifest with low back pain or sciatica. The degeneration is characterized by the loss of extracellular matrix integrity and dehydration in the nucleus pulposus. This compromises the viscoelastic property and compressive strength of the disc and therefore the capacity to withstand axial load, eventually causing the disc to collapse or leading to disc bulging or herniation due to abnormal strains on the surrounding annulus. Mesenchymal stem/stromal cells (MSCs) are attractive cell sources for engineering or repair of the disc tissues with respect to their ease of availability and capacity to expand in vitro. Moreover, recent investigations have proposed a potential of MSCs to differentiate into disc-like cells. This review discusses the approaches and concerns for engineering intervertebral disc through manipulating MSCs, with a highlight on the relevance of disc progenitor discovery. Ultimately, stem cell-based engineering of intervertebral disc may facilitate the preservation of motion segment function and address degenerative disc disease in future without spinal fusion. PMID:25429703

Tam, Wai-Kit; Cheung, Kenneth M C; Leung, Victor Y L

2014-11-25

120

Non-reclosing pressure relief device for vacuum systems  

DOEpatents

A non-reclosing overpressure protection device such as a rupture disc provides a non-reclosing opening upon forcible contact with a knife blade. A bellows, having an inlet capable of being sealably connected to a source of pressure (the vacuum system) and an outlet containing the rupture disc, transmits the pressure in the system to the disc. The bellows maintains the disc away from the knife when the pressure is below an overpressure amount, and carries the disc to a position when the pressure is above an overpressure amount where the disc is ruptured by the knife.

Swansiger, William A. (Livermore, CA)

1994-01-01

121

Non-reclosing pressure relief device for vacuum systems  

DOEpatents

A non-reclosing overpressure protection device such as a rupture disc provides a non-reclosing opening upon forcible contact with a knife blade. A bellows, having an inlet capable of being sealably connected to a source of pressure (the vacuum system) and an outlet containing the rupture disc, transmits the pressure in the system to the disc. The bellows maintains the disc away from the knife when the pressure is below an overpressure amount, and carries the disc to a position when the pressure is above an overpressure amount where the disc is ruptured by the knife. 6 figures.

Swansiger, W.A.

1994-02-08

122

Omental mesothelial cyst herniated to the thorax through the esophageal hiatus: a case report.  

PubMed

Both mesothelial cyst in the omentum and omental herniation through the esophageal hiatus without abdominal visceral involvement are rare. We report a case of omental mesothelial cyst herniated to the thorax through the esophageal hiatus. PMID:20871418

Lee, Eun Ju; Choi, Yo Won; Jeon, Seok Chol; Heo, Jeong-Nam; Park, Choong Ki; Paik, Seung Sam; Chung, Won Sang

2011-08-01

123

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

PubMed

Degeneration of the intervertebral disc (IVD) and disc herniation are two causes of low back pain. The aetiology of these disorders is unknown, but tissue weakening, which primarily occurs due to inherited genetic factors, ageing, nutritional compromise and loading history, is the basic factor causing disc degeneration. Symptomatic disc herniation mainly causes radicular pain. Current treatments of intervertebral disc degeneration and low back pain are based on alleviating the symptoms and comprise administration of painkillers or surgical methods such as spinal fusion. None of these methods is completely successful. Current research focuses on regeneration of the IVD and particularly on regeneration of the nucleus pulposus. Less attention has been directed to the repair or regeneration of the annulus fibrosus, although this is the key to successful nucleus pulposus, and therewith IVD, repair. This review focuses on the importance of restoring the function of the annulus fibrosus, as well as on the repair, replacement or regeneration of the annulus fibrosus in combination with restoration of the function of the nucleus pulposus, to treat low back pain. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24616324

Sharifi, Shahriar; Bulstra, Sjoerd K; Grijpma, Dirk W; Kuijer, Roel

2014-02-25

124

Surgical treatment of thoracic disc disease via minimally invasive lateral transthoracic trans/retropleural approach: analysis of 33 patients.  

PubMed

Thoracic disc herniations are associated with serious neurological consequences if not treated appropriately. Although a number of techniques have been described, there is no consensus about the best surgical approach. In this study, the authors report their experience in the operative management of patients with thoracic disc herniations using minimally invasive lateral transthoracic trans/retropleural approach. A series of 33 consecutive patients with thoracic disc herniations who underwent anterior spinal cord decompression followed by instrumented fusion through lateral approach is being reported. Demographic and radiographic data, perioperative complications, and clinical outcomes were reviewed. Forty disc levels in 33 patients (18F/15M; mean age, 52.9) were treated. Twenty-three patients presented with myelopathy (69 %), 31 had radiculopathy (94 %), and 31 had axial pain (94 %). Among patients with myelopathy, 14 (42.4 %) had bladder and/or bowel dysfunction. In the last eight cases (24 %), the approach was retropleural instead of transpleural. Patients were followed up for 18.2 months on average. The mean length of hospital stay was 5 days. None of the patients developed neurological deterioration postoperatively. Among 23 patients who had myelopathy signs, 21 (91 %) had improved postoperatively. The mean preoperative visual analog scale pain score, Oswestry Disability Index score, SF-36 PCS, and mental component summary scores were 7.5, 42.4, 29.6, and 37.5 which improved to 3.5, 33.2, 35.5, and 52.6, respectively. Perioperative complications occurred in six patients (18.1 %), all of which resolved uneventfully. Minimally invasive lateral transthoracic trans/retropleural approach is a safe and efficacious technique for achieving adequate decompression in thoracic disc herniations in a less invasive manner than conventional approaches. PMID:23572229

Nacar, Osman Arikan; Ulu, Mustafa Onur; Pekmezci, Murat; Deviren, Vedat

2013-07-01

125

DETAIL OF FILTER DISCS ON DENVER FILTER IN CO91107. AS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL OF FILTER DISCS ON DENVER FILTER IN CO-91-107. AS DISCS SLOWLY ROTATE, VACUUM INSIDE DISCS ATTRACT SLURRY IN THE SUMP AND DEWATERS CONCENTRATE AS DISCS MOVE THROUGH AIR. FURTHER ROTATION PASSES A BAR TO SCRAPE OFF DRIED METAL CONCENTRATE, ASSISTED BY BLASTS OF COMPRESSED AIR. METAL CONCENTRATE READY FOR SHIPMENT TO SMELTER FALLS INTO BIN BELOW. EIMCO FILTERS OPERATE SIMILARLY. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

126

Dynamics of Astrophysical Discs  

NASA Astrophysics Data System (ADS)

Preface; Names and addresses of participants; Conference photograph; 1. Spiral waves in Saturn's rings; 2. Structure of the Uranian rings; 3. Planetary rings: theory; 4. Simulations of light scattering in planetary rings; 5. Accretion discs around young stellar objects and the proto-Sun; 6. The ß Pictoris disc: a planetary rather than a protoplanetary one; 7. Optical polarimetry and thermal imaging of the disc axound ß Pictoris; 8. Observations of discs around protostars and young stars; 9. VLA observations of ammonia towaxd moleculax outflow sources; 10. Derivation of the physical properties of molecular discs by an MEM method; 11. Masers associated with discs around young stars; 12. The nature of polarisation discs axound young stars; 13. The correlation between the main parameters of the interstellar gas (including Salpeter's spectrum of masses) as a result of the development of turbulent Rossby waves; 14. Discs in cataclysmic variables and X-ray binaries; 15. A disc instability model for soft X-ray transients containing black holes; 16. X-ray variability from the accretion disc of NGC 5548; 17. Viscously heated coronae and winds around accretion discs; 18. Optical emission line profiles of symbiotic stars; 19. The effect of formation of Fell in winds confined to discs for luminous stars; 20. Observational evidence for accretion discs in active galactic nuclei; 21. The fuelling of active galactic nuclei by non-axisynlinetric instabilities; 22. The circum-nuclear disc in the Galactic centre; 23. Non-axisymmetric instabilities in thin self-gravitating differentially rotating gaseous discs; 24. Non-linear evolution of non-axisymmetric perturbations in thin self-gravitating gaseous discs; 25. Eccentric gravitational instabilities in nearly Keplerian discs; 26. Gravity mode instabilities in accretion tori; 27. The stability of viscous supersonic shear flows - critical Reynolds numbers and their implications for accretion discs; 28. Asymptotic analysis of overstable convective modes of uniformly rotating stars; 29. Polytropic models in very rapid rotation; 30. Distribution and kinematics of gas in galaxy discs; 31. Are the smallest galaxies optically invisible?; 32. Can we understand the constancy of rotation curves?; 33. How well do we know the surface density of the Galactic disc?; 34. On the heating of the Galactic disc; 35. The bulge-disc interaction in galactic centres; 36. Dynamics of the large-scale disc in NGC 1068; 37. The flow of gas in barred galaxies; 38. The warped dust lane in A1029-459; 39. Structure and evolution of dissipative non-planar galactic discs; 40. Non-axisymmetric magnetic fields in turbulent gas discs; 41. Non-axisymmetric disturbances in galactic discs; 42. Spiral instabilities in N-body simulations; 43. Long-lived spiral waves in N-body simulations; 44. Overstable modes in stellar disc systems; 45. Galactic seismological approach to the spiral galaxy NGC 3198; 46. Characteristics of bars from 3-1) simulations; 47. Spirals and bars in linear theory; 48. Stellar hydrodynamical solutions for Eddington discs; 49. Theory of gradient instabilities of the gaseous Galactic disc and rotating shallow water; 50. Stability criteria for gravitating discs; 51. Stability of two-component galactic discs; 52. The smoothed particle hydrodynamics of galactic discs; 53. Tidal triggering of active disc galaxies by rich clusters; 54. The formation of spiral arms in early stages of galaxy interaction; 55. Formation of leading spiral arms in retrograde galaxy encounters; 56. The influence of galaxy interactions on stellar bars; 57. Disc galaxies - work in progress in Gothenburg; 58. Motion of a satellite in a disc potential; 59. Observer's summary; 60. Common processes and problems in disc dynamics; Citation index; Index of authors; Subject index.

Sellwood, J. A.

2004-01-01

127

Omental herniation through the esophageal hiatus mimics mediastinal lipomatous tumor.  

PubMed

A 61-year-old man with a mediastinal abnormal mass on computed tomography is presented. Sagittal sections of magnetic resonance imaging (MRI) clearly indicated the continuity of the fatty mass from the abdomen to the thorax. The diagnosis was an omental herniation through the esophageal hiatus during the operation. First, we returned the omentum into the abdominal cavity, and then repaired the hiatus. The patient had an uneventful postoperative recovery. A herniation of the omentum through the esophageal hiatus is rare; this case is the tenth found in both English and Japanese literatures. The coronal and sagittal planes of MRI were useful in distinguishing the herniation of omentum through the esophageal hiatus from lipomatous tumor. It is our intention of raising awareness about the disease. PMID:15651406

Yunoki, Junji; Ohteki, Hitoshi; Naito, Kozo; Hisajima, Kazuhiro

2004-12-01

128

Omental herniation through the esophageal hiatus in a cat.  

PubMed

A four-year-old male cat was presented with regurgitation. Thoracic radiography and contrast radiogram showed a large oval mass and elevated esophagus. Exploratory thoracotomy showed omental herniation into the posterior mediastium through the esophageal hiatus. Because the mass of the omental herniation was so large, celiotomy through a paracostal incision was combined in order to return the omentum to its normal position. The diameter of the esophageal hiatus was approximately 1 cm but no fibrous adhesion was observed around the hiatus. Continuous 1-0 surgical sutures on the hiatus reduced the diameter of the hiatus. The cat made a successful postoperative recovery without complications. PMID:12520113

Mitsuoka, Kokori; Tanaka, Ryou; Nagashima, Yukiko; Hoshi, Katsuichiro; Matsumoto, Hirokazu; Yamane, Yoshihisa

2002-12-01

129

Percutaneous laser disc decompression for thoracic disc disease: report of 10 cases  

PubMed Central

Background: Discogenic pain or herniation causing neural impingement of the thoracic vertebrae is less common than that in the cervical or lumbar regions. Treatment of thoracic discogenic pain usually involves conservative measures. If this fails, conventional fusion or discectomy can be considered, but these procedures carry significant risk. Objectives: To assess the efficacy and safety of percutaneous laser disc decompression (PLDD) for the treatment of thoracic disc disease. Methods: Ten patients with thoracic discogenic pain who were unresponsive to conservative intervention underwent the PLDD procedure. Thoracic pain was assessed using the Visual Analog Scale (VAS) scores preoperatively and at 6-month intervals with a minimum of 18-months follow-up. Patients were diagnosed and chosen for enrollment based on abnormal MRI findings and positive provocative discograms. Patients with gross herniations were not included. Results: Length of follow-up ranged from 18 to 31 months (mean: 24.2 mo). Median pretreatment thoracic VAS score was 8.5 (range: 5-10) and median VAS score at final follow-up was 3.8 (range: 0-9). Postoperative improvement was significant with a 99% confidence interval. Of interest, patients generally fell into two groups, those with significant pain reduction and those with little to no improvement. Although complications such as pneumothorax, discitis, or nerve damage were possible, no adverse events occurred during the procedures. Limitations: The study is limited by its small size and lack of a sham group. Larger controlled studies are warranted. Conclusions: With further clinical evidence, PLDD could be considered a viable option with a low risk of complication for the treatment of thoracic discogenic pain that does not resolve with conservative treatment. PMID:20567616

Haufe, Scott M.W.; Mork, Anthony R.; Pyne, Morgan; Baker, Ryan A.

2010-01-01

130

Turbine disc sealing assembly  

DOEpatents

A disc seal assembly for use in a turbine engine. The disc seal assembly includes a plurality of outwardly extending sealing flange members that define a plurality of fluid pockets. The sealing flange members define a labyrinth flow path therebetween to limit leakage between a hot gas path and a disc cavity in the turbine engine.

Diakunchak, Ihor S.

2013-03-05

131

Aetiology of Herniation of the Hindbrain in Craniosynostosis  

Microsoft Academic Search

The occurrence and extent of herniation of the hindbrain has been evaluated in a population of children with craniosynostosis by means of magnetic resonance imaging of the craniocervical junction. The role of intracranial pressure (ICP), posterior fossa size and hydrocephalus in the development of this deformity has also been assessed. Magnetic resonance imaging (Siemens Magnetom 1.5T) was reviewed in 27

Dominic N. P. Thompson; William Harkness; Barry M. Jones; Richard D. Hayward

1997-01-01

132

Herniation of calcified cervical intervertebral disk in children.  

PubMed

Childhood intervertebral disk calcification is a rare clinical entity and usually has a benign course, generally undergoing spontaneous resolution. However, rapid neurologic deterioration due to herniation, found in both of our cases of calcified cervical intervertebral disks, required urgent anterior discectomy and fusion, resulting in excellent recovery. PMID:1298105

Mohanty, S; Sutter, B; Mokry, M; Ascher, P W

1992-12-01

133

Minimally Invasive Oxygen-Ozone Therapy for Lumbar Disk Herniation  

Microsoft Academic Search

BACKGROUND AND PURPOSE: Oxygen-ozone therapy is a minimally invasive treatment for lumbar disk herniation that exploits the biochemical properties of a gas mixture of oxygen and ozone. We assessed the therapeutic outcome of oxygen-ozone therapy and compared the outcome of administering medical ozone alone with the outcome of medical ozone followed by injection of a corticosteroid and an anesthetic at

Cosma F. Andreula; Luigi Simonetti; Fabio de Santis; Raffaele Agati; Renata Ricci; Marco Leonardi

134

Potential regenerative treatment strategies for intervertebral disc degeneration in dogs  

PubMed Central

Pain due to spontaneous intervertebral disc (IVD) disease is common in dogs. In chondrodystrophic (CD) dogs, IVD disease typically develops in the cervical or thoracolumbar spine at about 3–7 years of age, whereas in non-chondrodystrophic (NCD) dogs, it usually develops in the caudal cervical or lumbosacral spine at about 6–8 years of age. IVD degeneration is characterized by changes in the biochemical composition and mechanical integrity of the IVD. In the degenerated IVD, the content of glycosaminoglycan (GAG, a proteoglycan side chain) decreases and that of denatured collagen increases. Dehydration leads to tearing of the annulus fibrosus (AF) and/or disc herniation, which is clinically characterized by pain and/or neurological signs. Current treatments (physiotherapy, anti-inflammatory/analgesic medication, surgery) for IVD disease may resolve neurological deficits and reduce pain (although in many cases insufficient), but do not lead to repair of the degenerated disc. For this reason, there is interest in new regenerative therapies that can repair the degenerated disc matrix, resulting in restoration of the biomechanical function of the IVD. CD dogs are considered a suitable animal model for human IVD degeneration because of their spontaneous IVD degeneration, and therefore studies investigating cell-, growth factor-, and/or gene therapy-based regenerative therapies with this model provide information relevant to both human and canine patients. The aim of this article is to review potential regenerative treatment strategies for canine IVD degeneration, with specific emphasis on cell-based strategies. PMID:24387033

2014-01-01

135

Central nervous system lesions and cervical disc herniations in amateur divers  

Microsoft Academic Search

Permanent neuropsychological changes such as memory disturbances and depression have been found in professional divers, even in those who have never had decompression sickness. The changes are probably the result of intravascular gas bubbles insufficient to cause acute symptoms. We examined amateur divers with long histories of self-contained underwater breathing apparatus diving by magnetic resonance imaging and compared them with

J Reul; A Jung; A Thron; J Weis; K Willmes

1995-01-01

136

Percutaneous Laser Disc Decompression (PLDD): Experience and Results From Multiple Centers and 19,880 Procedures  

NASA Astrophysics Data System (ADS)

In mid-February 1986, Peter Ascher and Daniel Choy performed the first Percutaneous Laser Disc Decompression (PLDD) at the Neurosurgical Department, University of Graz, Graz, Austria. It was planned to deliver 1000 joules with a Nd:YAG laser to a herniated L4-5 disc causing sciatica. At 600 joules the procedure was terminated because the pain was gone. Since then, PLDD has spread all over the world, with procedures being performed in the entire spine except for T1-T4 because these discs do not permit percutaneous access with a needle. The success rate has ranged from 70 to 89%, and the complication rate, chiefly discitis, from 0.3 to 1.0%. When successful, return to normal work averages one week. Long term follow-up to 23 years yields a recurrence rate of 4-5%.

Paolo Tassi, Gian; Choy, Daniel S. J.; Hellinger, Johannes; Hellinger, Stefan; Lee, Sang-Ho

2010-05-01

137

BLU-RAY DISC  

Microsoft Academic Search

In the two decades that followed the initial CD-press conference in 1979, the optical storage industry had grown up. A complete\\u000a family of CD formats has been defined and developed. There were read-only, write once and rewritable discs on the market.\\u000a The price of these discs had gradually come down to very affordable levels. Many suppliers offered popular optical disc

J. A. M. M. Haaren; M. Kuijper; Yourii V. Martynov; Benno H. W. Hendriks; Ferry Zijp; Jan Aarts; Jan-Peter Baartman; Gerard Rosmalen; Jean J. H. B. Schleipen; Henk Houten; Tatsuya Narahara; Shoei Kobayashi; Masayuki Hattori; Yoshihide Shimpuku; Gijs J. Enden; Joost A. H. M. Kahlman; Marten Dijk; Roel Woudenberg; I. Ubbens; L. Spruijt; J. M. ter Meulen; K. Schep; Shigeru Furumiya; Bert Stek; Hiromichi Ishibashi; Tamotsu Yamagami; Jaap H. M. Neijzen; Erwin R. Meinders; Helmar Santen

138

Percutaneous breast implant herniation: a rare complication of miliary TB.  

PubMed

We describe the case of a 46-year-old female patient treated for disseminated tuberculosis (TB) infection involving the lungs, urinary tract and skin. Following initiation of antituberculous therapy, the patient's right breast implant eroded through the overlying skin and was seen to be herniating through the resulting defect. The breast implant was removed under local anaesthetic and histological analysis of the resected tissue demonstrated granuloma formation consistent with periprosthetic TB. Wound healing following implant removal was poor and future breast augmentation surgery was only considered following completion of 12?months anti-TB treatment. This case constitutes the first report in the literature of percutaneous breast implant herniation resulting from periprosthetic infection with TB. A high index of suspicion is required to ensure early detection and timely management of TB and, in cases where periprosthetic pus aspirate is sterile, mycobacterial infection must be actively excluded. PMID:25568276

Dale, Adam P; Dedicoat, Martin J; Saleem, Tausif; Moran, Ed

2015-01-01

139

Congenital diaphragmatic hernia: delayed presentation with asymptomatic spleenic herniation.  

PubMed

Patients with congenital diaphragmatic hernia (CDH) usually present in the immediate neonatal period with respiratory distress. Presentation beyond the neonatal period has, however, been reported. We report a case of a 3-year-old child who presented with a six months history of respiratory symptoms and had been subjected to a variety of therapies like antibiotics, antitubercular medication and two attempts at putting an intercostal tube, as radiographs were suggestive of pleural effusion. This study highlights the importance of a high index of suspicion, relevance of thorough clinical examination and non-invasive diagnostic modalities along with an uncommon occurrence of asymptomatic spleenic herniation at such a later age. Spleenic herniation is rare outside neonatal period. PMID:11845935

Sehgal, Arvind; Chandra, Jagdish; Singh, Varinder; Dutta, A K; Bagga, Deepak

2002-01-01

140

Acute renal failure caused by bilateral ureteral herniation through the sciatic foramen.  

PubMed

Ureteral herniation is rare. Only a few cases of bilateral ureterosciatic herniation have been reported. We report the case of a 74-year-old woman with flank pain and acute renal failure. The initial ultrasound scan showed bilateral hydronephrosis. Follow-up computed tomography imaging demonstrated sciatic herniation of both ureters, causing bilateral hydronephrosis and hydroureter. The patient underwent bilateral retrograde ureterography and ureteral stent placement, with improvement in renal function to normal limits. Observation after stent removal demonstrated recurrent sciatic herniation of both ureters. Definitive surgical correction was performed by way of laparoscopic bilateral ureterolysis and sciatic notch hernia repair using mesh. PMID:23602799

Whyburn, James J; Alizadeh, Ahmadreza

2013-06-01

141

Herniation of the spinal cord 38 years after childhood trauma  

Microsoft Academic Search

We report an unusual post-traumatic spinal cord herniation, which became symptomatic 38 years after the trauma. A 44-year-old man presented with a 2-year history of increasing impotence, neuropathic bladder dysfunction and dissociated sensory loss below the level of T6. At the age of 6 years he had a severe blunt spinal injury with transient paraparesis. MRI revealed right lateral and

H. Urbach; B. Kaden; U. Pechstein; L. Solymosi

1996-01-01

142

Vitamin K deficiency bleeding presenting as impending brain herniation.  

PubMed

It is presently a universal practice to administer vitamin K at birth. Hence, the serious bleeding manifestations from vitamin K deficiency are nowadays very rare. We describe a case of late vitamin K deficiency bleeding presenting as intracranial hemorrhage with impending coning and the related review of literature. Such severe bleeding episodes due to vitamin K deficiency are associated with multiple cranial involvement and impending brain herniation is probably rare. PMID:21042512

Gopakumar, H; Sivji, R; Rajiv, P K

2010-01-01

143

Vitamin K deficiency bleeding presenting as impending brain herniation  

PubMed Central

It is presently a universal practice to administer vitamin K at birth. Hence, the serious bleeding manifestations from vitamin K deficiency are nowadays very rare. We describe a case of late vitamin K deficiency bleeding presenting as intracranial hemorrhage with impending coning and the related review of literature. Such severe bleeding episodes due to vitamin K deficiency are associated with multiple cranial involvement and impending brain herniation is probably rare. PMID:21042512

Gopakumar, H.; Sivji, R.; Rajiv, P. K.

2010-01-01

144

Cervical lung lobe herniation in dogs identified by fluoroscopy  

PubMed Central

This study aimed to determine the frequency of cervical lung lobe herniation (CLLH) in dogs evaluated fluoroscopically and to identify associated characteristics. Reports of diagnostic procedures and patient summaries from 2008 to 2010 were reviewed retrospectively. Signalment, body weight, duration of cough, presence of heart murmur and airway collapse, and radiographic findings were compared between dogs with and without CLLH. Of the 121 dogs that were examined, CLLH occurred in 85 (70%). The extra-thoracic trachea kinked during herniation in 33 (39%) dogs with CLLH. Collapse of the intra-thoracic trachea (assessed fluoroscopically or bronchoscopically) and collapse of major bronchi (assessed fluoroscopically) were strongly associated with CLLH. Although redundant dorsal tracheal membrane on radiographs was associated with CLLH, extra-thoracic tracheal collapse, assessed fluoroscopically or bronchoscopically, was not. No other associations were found. Cervical lung lobe herniation was present in most dogs evaluated during cough and was associated with intra-thoracic large airway collapse, but not duration of cough. PMID:24155415

Nafe, Laura A.; Robertson, Ian D.; Hawkins, Eleanor C.

2013-01-01

145

Early Postoperative Results after Removal of Cranially Migrated Lumbar Disc Prolapse: Retrospective Comparison of Three Different Surgical Strategies  

PubMed Central

Background. To compare the early postoperative results of three surgical approaches to lumbar disc herniations that migrated cranially. Minimally invasive techniques such as the translaminar and endoscopic transforaminal approaches are utilized in patients with lumbar disc herniations to gain access to cranially located disc material and to avoid the potentially destabilizing resection of ligament and bone tissue, which is associated with an extended interlaminar approach. Methods. This retrospective study compares the postoperative pain and functional capacity levels of 69 patients who underwent an interlaminar (Group A, n = 27), a translaminar (Group B, n = 22), or an endoscopic transforaminal procedure (Group C, n = 20). Results. Median VAS scores for leg pain decreased significantly from before to after surgery in all groups. Surgical revisions were required in thirteen cases (five in Group A, one in Group B, and seven in Group C; P = 0.031). After six weeks, there were significant differences in back pain and functional outcome scores and in the results for the MacNab criteria but not in leg pain scores. Conclusions. The interlaminar and translaminar techniques were the safest and fastest ways of gaining access to cranially migrated disc material and the most effective approaches over a period of six weeks. PMID:25478234

Schulz, C.; Kunz, U.; Mauer, U. M.; Mathieu, R.

2014-01-01

146

Recurrent wound dehiscence and small bowel herniation following Caesarean section in a woman with hidradenitis suppurativa.  

PubMed

Caesarean wound dehiscence that is severe enough to result in bowel herniation is exceptionally rare. This case describes a woman who experienced wound dehiscence following each of her two Caesarean sections, with bowel herniation present in the second case. The contribution of her comorbid hidradenitis suppurativa will be discussed. PMID:24876503

Fernando, Magage; Schultz, Meleesa J

2014-01-01

147

Coplanar circumbinary debris discs  

NASA Astrophysics Data System (ADS)

We present resolved Herschel images of circumbinary debris discs in the ? CrB (HD 139006) and ? Tri (HD13161) systems. By modelling their structure, we find that both discs are consistent with being aligned with the binary orbital planes. Though secular perturbations from the binary can bring the disc into alignment, in both cases the alignment time at the distances at which the disc is resolved is greater than the stellar age, so we conclude that the coplanarity was primordial. Neither disc can be modelled as a narrow ring, requiring extended radial distributions. To satisfy both the Herschel and mid-infrared images of the ? CrB disc, we construct a model that extends from 1 to 300 au, whose radial profile is broadly consistent with a picture where planetesimal collisions are excited by secular perturbations from the binary. However, this model is also consistent with stirring by other mechanisms, such as the formation of Pluto-sized objects. The ? Tri disc is modelled as a disc that extends from 50 to 400 au. A model with depleted (rather than empty) inner regions also reproduces the observations and is consistent with binary and other stirring mechanisms. As part of the modelling process, we find that the Herschel PACS (Photodetector and Array Camera & Spectrometer) beam varies by as much as 10 per cent at 70 ?m and a few per cent at 100 ?m. The 70 ?m variation can therefore hinder image interpretation, particularly for poorly resolved objects. The number of systems in which circumbinary debris disc orientations have been compared with the binary plane is now 4. More systems are needed, but a picture in which discs around very close binaries (? CrB, ? Tri and HD 98800, with periods of a few weeks to a year) are aligned, and discs around wider binaries (99 Her, with a period of 50 yr) are misaligned, may be emerging. This picture is qualitatively consistent with the expectation that the protoplanetary discs from which the debris emerged are more likely to be aligned if their binaries have shorter periods.

Kennedy, G. M.; Wyatt, M. C.; Sibthorpe, B.; Phillips, N. M.; Matthews, B. C.; Greaves, J. S.

2012-11-01

148

Vacuum Technology  

SciTech Connect

The environmental condition called vacuum is created any time the pressure of a gas is reduced compared to atmospheric pressure. On earth we typically create a vacuum by connecting a pump capable of moving gas to a relatively leak free vessel. Through operation of the gas pump the number of gas molecules per unit volume is decreased within the vessel. As soon as one creates a vacuum natural forces (in this case entropy) work to restore equilibrium pressure; the practical effect of this is that gas molecules attempt to enter the evacuated space by any means possible. It is useful to think of vacuum in terms of a gas at a pressure below atmospheric pressure. In even the best vacuum vessels ever created there are approximately 3,500,000 molecules of gas per cubic meter of volume remaining inside the vessel. The lowest pressure environment known is in interstellar space where there are approximately four molecules of gas per cubic meter. Researchers are currently developing vacuum technology components (pumps, gauges, valves, etc.) using micro electro mechanical systems (MEMS) technology. Miniature vacuum components and systems will open the possibility for significant savings in energy cost and will open the doors to advances in electronics, manufacturing and semiconductor fabrication. In conclusion, an understanding of the basic principles of vacuum technology as presented in this summary is essential for the successful execution of all projects that involve vacuum technology. Using the principles described above, a practitioner of vacuum technology can design a vacuum system that will achieve the project requirements.

Biltoft, P J

2004-10-15

149

Vacuum mechatronics  

NASA Technical Reports Server (NTRS)

The discipline of vacuum mechatronics is defined as the design and development of vacuum-compatible computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. The importance of vacuum mechatronics is growing with an increased application of vacuum in space studies and in manufacturing for material processing, medicine, microelectronics, emission studies, lyophylisation, freeze drying and packaging. The quickly developing field of vacuum mechatronics will also be the driving force for the realization of an advanced era of totally enclosed clean manufacturing cells. High technology manufacturing has increasingly demanding requirements for precision manipulation, in situ process monitoring and contamination-free environments. To remove the contamination problems associated with human workers, the tendency in many manufacturing processes is to move towards total automation. This will become a requirement in the near future for e.g., microelectronics manufacturing. Automation in ultra-clean manufacturing environments is evolving into the concept of self-contained and fully enclosed manufacturing. A Self Contained Automated Robotic Factory (SCARF) is being developed as a flexible research facility for totally enclosed manufacturing. The construction and successful operation of a SCARF will provide a novel, flexible, self-contained, clean, vacuum manufacturing environment. SCARF also requires very high reliability and intelligent control. The trends in vacuum mechatronics and some of the key research issues are reviewed.

Hackwood, Susan; Belinski, Steven E.; Beni, Gerardo

1989-01-01

150

Vacuum Energy  

E-print Network

There appears to be three, perhaps related, ways of approaching the nature of vacuum energy . The first is to say that it is just the lowest energy state of a given, usually quantum, system. The second is to equate vacuum energy with the Casimir energy. The third is to note that an energy difference from a complete vacuum might have some long range effect, typically this energy difference is interpreted as the cosmological constant. All three approaches are reviewed, with an emphasis on recent work. It is hoped that this review is comprehensive in scope. There is a discussion on whether there is a relation between vacuum energy and inertia. The solution suggested here to the nature of the vacuum is that Casimir energy can produce short range effects because of boundary conditions, but that at long range there is no overall effect of vacuum energy, unless one considers lagrangians of higher order than Einstein's as vacuum induced. No original calculations are presented in support of this position. This is not a review of the cosmological constant {\\it per se}, but rather vacuum energy in general, my approach to the cosmological constant is not standard.

Mark D. Roberts

2000-12-07

151

Vacuum Virtues  

ERIC Educational Resources Information Center

Upright vacuums, like cars, vary in quality, features and performance. Like automobiles, some uprights are reliable, others may be problematic, and some become a problem as a result of neglect or improper use. So, how do education institutions make an informed choice and, having done so, ensure that an upright vacuum goes the distance? In this…

Rathey, Allen

2007-01-01

152

Gravitational vacuum  

NASA Astrophysics Data System (ADS)

The existence of a special gravitational vacuum is considered in this paper. A phenomenological method differing from the traditional Einsteinian formalization is utilized. Vacuum, metric and matter form a complex determined by field equations and at great distances from gravitational masses vacuum effects are small but could be large in powerful fields. Singularities and black holes justify the approach as well as the Ambartsmyan theory concerning the existence of supermassive and superdense prestallar bodies that then disintegrate. A theory for these superdense bodies is developed involving gravitational field equations that describe the vacuum by an energy momentum tensor and define the field and mass distribution. Computations based on the theory for gravitational radii with incompressible liquid models adequately reflecting real conditions indicate that a gravitational vacuum could have considerable effects on superdense stars and could have radical effects for very large masses.

Grigoryan, L. S.; Saakyan, G. S.

1984-09-01

153

Spontaneous disc degeneration in the baboon model: magnetic resonance imaging and histopathologic correlation.  

PubMed

Degenerative disc disease is a major source of disability in humans. The baboon model is an excellent natural disease model to study comparable human disease, because baboons are relatively large (adult males 20-26 kg, adult females 12-17 kg), long-lived (30-45 years), well defined, easy to use, and closely related to humans. Published investigations with plain radiographs of disc degeneration in baboons indicated vertebral anatomy and changes that were remarkably similar to those seen in humans, and it would be valuable to determine if magnetic resonance imaging (MRI) and histopathologic evaluation would be useful methods for studying the model, as MRI allows multi-planar visualization of tissues without the use of intravenous contrast and it is superior for evaluating disc hydration, annulus tears, and herniations. The thoracolumbar junctions from 47 randomly selected baboons, ranging in age from 2 weeks to 34 years, were evaluated with MRI and histopathology. Excellent correlation with MRI was observed for changes in disc desiccation, height, and age (P < 0.001). The pathologic analysis demonstrated P values of < 0.001 when comparing histopathology with age and MRI results. All severely degenerated discs seen by MRI were in baboons 14 years of age or older. PMID:11990242

Platenberg, R C; Hubbard, G B; Ehler, W J; Hixson, C J

2001-10-01

154

Pain and disability correlated with disc degeneration via magnetic resonance imaging in scoliosis patients  

PubMed Central

Prior imaging studies of scoliosis patients attempted to demonstrate a relationship between plain radiographic curve patterns and curve progression and pain, or used magnetic resonance imaging (MRI) to focus on spinal cord abnormalities. Pain in scoliosis patients may differ from nondeformity patients, yet may still be discogenic. The purpose of this study was to assess the possible relationship of degenerative disc findings on MRI to scoliosis patients’ pain. This prospective study enrolled scoliosis and control patients, all of whom had assessment for back pain (visual analog scale) and disability (Oswestry Index) and spinal MRI to identify prevalence and distribution of degenerative disc findings. Specifically, we assessed 60 consecutive pediatric and adult idiopathic scoliosis patients who had progressed to surgical treatment, 60 age- and gender-matched asymptomatic controls, and 172 nondeformity symptomatic degenerative disc disease patients who had progressed to surgical treatment. All subjects had independent analysis of their preoperative MRI for disc degeneration, disc herniation, Schmorl’s nodes, and inflammatory end plate changes. Imaging findings of the scoliosis patients were compared to those from asymptomatic and symptomatic control groups. Our results found that both pediatric and adult scoliosis patients had significantly more pain and disability than did asymptomatic controls (P < 0.001). The adult idiopathic scoliosis patients had pain and disability similar to those of surgical degenerative disc disease control groups. Disc degeneration and herniation (contained) were not related to pain. However, in the pediatric scoliosis patients, those with Schmorl’s nodes often had greater pain than those without (P = 0.01). Adults with painful scoliosis, typically occurring at the apex of the scoliosis or at the lumbosacral junction, had a significantly higher frequency of inflammatory end plate changes on MRI than did controls (P < 0.001). Prior studies have demonstrated a correlation of inflammatory end plate changes to lumbar discogenic pain. In conclusions, scoliosis patients who have progressed to surgical intervention, pediatric patients have varying degrees of pain, and those with Schmorl’s nodes may be at greater risk for pain. Adult scoliosis patients have multifactorial pain of which one component may be related to degeneration of the lower lumbar discs similar to that in nondeformity patients. Additionally, adult scoliosis patients may have MRI findings consistent with discogenic pain at the apex of their curvature, most commonly at the proximal lumbar levels. PMID:17973128

Mullin, William J.

2007-01-01

155

Effectiveness and cost-effectiveness of rehabilitation after lumbar disc surgery (REALISE): design of a randomised controlled trial  

PubMed Central

Background Patients who undergo lumbar disc surgery for herniated discs, are advocated two different postoperative management strategies: a watchful waiting policy, or referral for rehabilitation immediately after discharge from the hospital. A direct comparison of the effectiveness and cost-effectiveness of these two strategies is lacking. Methods/Design A randomised controlled trial will be conducted with an economic evaluation alongside to assess the (cost-) effectiveness of rehabilitation after lumbar disc surgery. Two hundred patients aged 18–70 years with a clear indication for lumbar disc surgery of a single level herniated disc will be recruited and randomly assigned to either a watchful waiting policy for first six weeks or exercise therapy starting immediately after discharge from the hospital. Exercise therapy will focus on resumption of activities of daily living and return to work. Therapists will tailor the intervention to the individual patient’s needs. All patients will be followed up by the neurosurgeon six weeks postoperatively. Main outcome measures are: functional status, pain intensity and global perceived recovery. Questionnaires will be completed preoperatively and at 3, 6, 9, 12 and 26 weeks after surgery. Data will be analysed according to the intention-to-treat principle, using a linear mixed model for continuous outcomes and a generalised mixed model for dichotomous outcomes. The economic evaluation will be performed from a societal perspective. Discussion The results of this trial may lead to a more consistent postoperative strategy for patients who will undergo lumbar disc surgery. Trial registration Netherlands Trial Register: NTR3156 PMID:23560810

2013-01-01

156

Herniation of uncus and parahippocampal gyrus: an accidental finding on magnetic resonance imaging of cerebrum.  

PubMed

Idiopathic herniation of uncus and parahippocampal gyrus into the ambient cistern is a very rare entity, which could be mistaken for other pathology such as tumor. To the best of our knowledge, two prior cases of this kind of herniation have been described. One of these cases was with associated symptomatology and other abnormalities, and the other was characterized as idiopathic. In this case report, we report a case of accidental finding of a herniation of uncus and parahippocampal gyrus into the ambient cistern, without any other accompanying abnormalities, well depicted by magnetic resonance imaging without further necessity for surgical brain intervention. PMID:25610616

Yavarian, Yousef; Bayat, Michael; Brøndum Frøkjær, Jens

2015-01-01

157

Herniation of uncus and parahippocampal gyrus: an accidental finding on magnetic resonance imaging of cerebrum  

PubMed Central

Idiopathic herniation of uncus and parahippocampal gyrus into the ambient cistern is a very rare entity, which could be mistaken for other pathology such as tumor. To the best of our knowledge, two prior cases of this kind of herniation have been described. One of these cases was with associated symptomatology and other abnormalities, and the other was characterized as idiopathic. In this case report, we report a case of accidental finding of a herniation of uncus and parahippocampal gyrus into the ambient cistern, without any other accompanying abnormalities, well depicted by magnetic resonance imaging without further necessity for surgical brain intervention. PMID:25610616

Bayat, Michael; Brøndum Frøkjær, Jens

2015-01-01

158

The immediately failed lumbar disc surgery: incidence, aetiologies, imaging and management.  

PubMed

Studies on immediate failed back surgery syndrome (iFBSS) following lumbar microdiscectomy are rare. Our aim is to describe the incidence and the causes of these immediate failures to define the value of radiological imaging for identification of the underlying pathology and to propose a management algorithm. We defined iFBSS as persistence, deterioration or recurrence (during hospital stay) of radicular pain and/or sensorimotor deficits and/or sphincter dysfunction after microdiscectomy, which was uneventful from the surgeon's perspective. The medical records of 1546 patients undergoing discectomy for mediolateral lumbar disc herniations were screened for iFBSS. The pre- and postoperative imaging, surgical records, therapy and outcome of patients with iFBSS were reviewed. Forty-four of 1546 patients (2.8 %) with iFBSS were identified. All patients underwent reoperation. Overseen disc material/re-herniation (n?=?22), epidural hematoma (n?=?6), inadequate decompression of accompanying recessal stenosis (n?=?2) and dural tear with fascicle herniation (n?=?1) were found to be causative. In 13 patients, who revealed no clear pathology intraoperatively, we diagnosed a battered root syndrome (nerve root swelling due to excessive surgical manipulation). The correct diagnosis could be established by neuroradiological imaging in 25 of 43 radiologically investigated patients (57 %). In our study, the radiological workup was of limited value for the correct differentiation of the various aetiologies of iFBSS. Therefore, the authors believe that the treatment strategy should strongly rely on the clinical presentation. To avoid unnecessary surgery in cases of battered root syndrome, we propose to proceed to reoperation only in patients with new or persistent radiculopathy despite adequate antiedematous medical therapy. PMID:25242202

Rohde, V; Mielke, D; Ryang, Y; Gilsbach, J M

2015-01-01

159

Cumulative occupational lumbar load and lumbar disc disease – results of a German multi-center case-control study (EPILIFT)  

PubMed Central

Background The to date evidence for a dose-response relationship between physical workload and the development of lumbar disc diseases is limited. We therefore investigated the possible etiologic relevance of cumulative occupational lumbar load to lumbar disc diseases in a multi-center case-control study. Methods In four study regions in Germany (Frankfurt/Main, Freiburg, Halle/Saale, Regensburg), patients seeking medical care for pain associated with clinically and radiologically verified lumbar disc herniation (286 males, 278 females) or symptomatic lumbar disc narrowing (145 males, 206 females) were prospectively recruited. Population control subjects (453 males and 448 females) were drawn from the regional population registers. Cases and control subjects were between 25 and 70 years of age. In a structured personal interview, a complete occupational history was elicited to identify subjects with certain minimum workloads. On the basis of job task-specific supplementary surveys performed by technical experts, the situational lumbar load represented by the compressive force at the lumbosacral disc was determined via biomechanical model calculations for any working situation with object handling and load-intensive postures during the total working life. For this analysis, all manual handling of objects of about 5 kilograms or more and postures with trunk inclination of 20 degrees or more are included in the calculation of cumulative lumbar load. Confounder selection was based on biologic plausibility and on the change-in-estimate criterion. Odds ratios (OR) and 95% confidence intervals (CI) were calculated separately for men and women using unconditional logistic regression analysis, adjusted for age, region, and unemployment as major life event (in males) or psychosocial strain at work (in females), respectively. To further elucidate the contribution of past physical workload to the development of lumbar disc diseases, we performed lag-time analyses. Results We found a positive dose-response relationship between cumulative occupational lumbar load and lumbar disc herniation as well as lumbar disc narrowing among men and women. Even past lumbar load seems to contribute to the risk of lumbar disc disease. Conclusion According to our study, cumulative physical workload is related to lumbar disc diseases among men and women. PMID:19422710

Seidler, Andreas; Bergmann, Annekatrin; Jäger, Matthias; Ellegast, Rolf; Ditchen, Dirk; Elsner, Gine; Grifka, Joachim; Haerting, Johannes; Hofmann, Friedrich; Linhardt, Oliver; Luttmann, Alwin; Michaelis, Martina; Petereit-Haack, Gabriela; Schumann, Barbara; Bolm-Audorff, Ulrich

2009-01-01

160

Histology of Herniations through the Body Wall and Cuticle of Zooplankton from the Laurentian Great Lakes  

E-print Network

Histology of Herniations through the Body Wall and Cuticle of Zooplankton from the Laurentian Great a histologic and cyto- logic analysis of the protrusions and found that they are composed of apparently

161

Diaphragmatic Herniation through Prosthetic Material after Extrapleural Pneumonectomy: Be Aware of Tumor Recurrence  

PubMed Central

Extrapleural pneumonectomy (EPP) is indicated in selected group of patients with pleural mesothelioma. Diaphragmatic reconstruction represents a part of this complex operation. We present the case of a late diaphragmatic gastric herniation through prosthetic material after EPP. PMID:25360411

Pop, Daniel; Cohen, Charlotte; Schneck, Anne-Sophie; Nadeemy, Ahmad S.; Venissac, Nicolas; Mouroux, Jerome

2013-01-01

162

A Case of Spontaneous Temporomandibular Joint Herniation into the External Auditory Canal with Clicking Sound  

PubMed Central

A bony defect of the external auditory canal (EAC) and herniation of the temporomandibular joint (TMJ) can be caused by tumorous conditions, inflammation, trauma, and otologic procedures. Spontaneous TMJ herniation into the EAC can be caused by a congenital bony defect known as patent Huschke's foramen, which is a very rare condition. In our case, an objective clicking sound was produced when the patient opened his mouth. A protruding mass was found in the anterior wall of the EAC during mouth closing, and herniation of the TMJ was confirmed with computed tomography. Therefore, we thought the clicking sound of our case could have resulted from spontaneous TMJ herniation through the patent foramen of Huschke. PMID:24653913

Kim, Tae Hyun; Lee, Sun Kyu; Kim, Su Jin

2013-01-01

163

Case report: Complex retroperitoneal herniation after abdominoperineal resection  

PubMed Central

INTRODUCTION We describe the occurrence of a retroperitoneal hernia into the colonic mesentery after abdomoniperineal resection (APR) for rectal cancer. PRESENTATION OF CASE A 70 year old male presented with complete small bowel obstruction secondary to a complex retroperitoneal herniation. Operative repair was carried out with successful reduction of the hernia contents. DISCUSSION A review of the literature is reported concerning retroperitoneal hernia. This occurrence is rare in the adult. Management of the resultant pelvic space after APR is discussed. Closure of the pelvic peritoneum is helpful in avoiding this and other similar complications. CONCLUSION We believe this to be the first report of a small bowel obstruction secondary to this unusual hernia circumstance. Although rare, due vigilance and thorough imaging can lead to effective and timely management of this complication. PMID:22975445

Alkhoury, Fuad; Martin, Jeremiah

2012-01-01

164

A Study on Dispersion and Rate of Fat Infiltration in the Lumbar Spine of Patients with Herniated Nucleus Polpusus  

PubMed Central

[Purpose] This study investigated the relationship between herniated nucleus pulposus (HNP) and fat infiltration of muscles around the spine by measuring body mass index (BMI) and fat infiltration of the muscles around the spine. [Subjects and Methods] Subjects were 82 people, both men and women they were divided into two groups, a normal group and a patient group who were suffering from serious HNP between L4 and L5. Of the anthropometric measurement, and fat infiltration muscles by measuring the cross-sectional area from the center of the disc to the muscle around the spine and the cross-sectional area of fat infiltration. [Results] Fat infiltration rate of each lumbar layer in the normal group was different L34–L45 and L45–L5S1, but not between L23–L34. Fat infiltration in the muscle between the normal group and patients with HNP was different in the layers and the difference was greatest in the L5–S1 layer. [Conclusion] We performed correlation analysis of BMI and the total fat infiltration rate in each group to find the relationship between obesity and fat infiltration in the lumbar spine. Fat infiltration increased, and normal people or patients with chronic back pain are considered to be exposed to other diseases as fat infiltration in the lumbar spine increases. PMID:24567672

Kong, Bong-jun; Lim, Jong-soo; Kim, Kyung

2014-01-01

165

Surgical vs Nonoperative Treatment for Lumbar Disk Herniation  

PubMed Central

Context Lumbar diskectomy is the most common surgical procedure performed for back and leg symptoms in US patients, but the efficacy of the procedure relative to nonoperative care remains controversial. Objective To assess the efficacy of surgery for lumbar intervertebral disk herniation. Design, Setting, and Patients The Spine Patient Outcomes Research Trial, a randomized clinical trial enrolling patients between March 2000 and November 2004 from 13 multidisciplinary spine clinics in 11 US states. Patients were 501 surgical candidates (mean age, 42 years; 42% women) with imaging-confirmed lumbar intervertebral disk herniation and persistent signs and symptoms of radiculopathy for at least 6 weeks. Interventions Standard open diskectomy vs nonoperative treatment individualized to the patient. Main Outcome Measures Primary outcomes were changes from baseline for the Medical Outcomes Study 36-item Short-Form Health Survey bodily pain and physical function scales and the modified Oswestry Disability Index (American Academy of Orthopaedic Surgeons MODEMS version) at 6 weeks, 3 months, 6 months, and 1 and 2 years from enrollment. Secondary outcomes included sciatica severity as measured by the Sciatica Bothersomeness Index, satisfaction with symptoms, self-reported improvement, and employment status. Results Adherence to assigned treatment was limited: 50% of patients assigned to surgery received surgery within 3 months of enrollment, while 30% of those assigned to nonoperative treatment received surgery in the same period. Intent-to-treat analyses demonstrated substantial improvements for all primary and secondary outcomes in both treatment groups. Between-group differences in improvements were consistently in favor of surgery for all periods but were small and not statistically significant for the primary outcomes. Conclusions Patients in both the surgery and the nonoperative treatment groups improved substantially over a 2-year period. Because of the large numbers of patients who crossed over in both directions, conclusions about the superiority or equivalence of the treatments are not warranted based on the intent-to-treat analysis. Trial Registration clinicaltrials.gov Identifier: NCT00000410 PMID:17119140

Weinstein, James N.; Tosteson, Tor D.; Lurie, Jon D.; Tosteson, Anna N. A.; Hanscom, Brett; Skinner, Jonathan S.; Abdu, William A.; Hilibrand, Alan S.; Boden, Scott D.; Deyo, Richard A.

2008-01-01

166

The Chemistry of Optical Discs.  

ERIC Educational Resources Information Center

Explains the chemistry used in compact discs (CD), digital versatile discs (DVD), and magneto-optical (MO) discs focusing on the steps of initial creation of the mold, the molding of the polycarbonate, the deposition of the reflective layers, the lacquering of the CDs, and the bonding of DVDs. (Contains 15 references.) (YDS)

Birkett, David

2002-01-01

167

Vacuum Gauges  

NSDL National Science Digital Library

This is a description for a learning module from Maricopa Advanced Technology Education Center. This PDF describes the module; access may be purchased by visiting the MATEC website. Semiconductor manufacturing equipment requires the use of many different types of vacuum gauges. Selection is based on range of process operations and production requirements. This MATEC module explores the theory and functionality of vacuum gauges and provides many examples of different types of gauges. The focus is on understanding the operating ranges and application constraints of each type of gauge. Mathematical equations are used to explain calibration, sensitivity, and overall operations of each type of gauge.

2012-11-28

168

Stemming the Degeneration: IVD Stem Cells and Stem Cell Regenerative Therapy for Degenerative Disc Disease  

PubMed Central

The intervertebral disc (IVD) is immensely important for the integrity of vertebral column function. The highly specialized IVD functions to confer flexibility and tensile strength to the spine and endures various types of biomechanical force. Degenerative disc disease (DDD) is a prevalent musculoskeletal disorder and is the major cause of low back pain and includes the more severe degenerative lumbar scoliosis, disc herniation and spinal stenosis. DDD is a multifactorial disorder whereby an imbalance of anabolic and catabolic factors, or alterations to cellular composition, or biophysical stimuli and genetic background can all play a role in its genesis. However, our comprehension of IVD formation and theetiology of disc degeneration (DD) are far from being complete, hampering efforts to formulate appropriate therapies to tackle DD. Knowledge of the stem cells and various techniques to manipulate and direct them to particular fates have been promising in adopting a stem-cell based regenerative approach to DD. Moreover, new evidence on the residence of stem/progenitor cells within particular IVD niches has emerged holding promise for future therapeutic applications. Existing issues pertaining to current therapeutic approaches are also covered in this review. PMID:23951558

Sivakamasundari, V; Lufkin, Thomas

2013-01-01

169

Mechanotransduction in intervertebral discs  

PubMed Central

Mechanotransduction plays a critical role in intracellular functioning—it allows cells to translate external physical forces into internal biochemical activities, thereby affecting processes ranging from proliferation and apoptosis to gene expression and protein synthesis in a complex web of interactions and reactions. Accordingly, aberrant mechanotransduction can either lead to, or be a result of, a variety of diseases or degenerative states. In this review, we provide an overview of mechanotransduction in the context of intervertebral discs, with a focus on the latest methods of investigating mechanotransduction and the most recent findings regarding the means and effects of mechanotransduction in healthy and degenerative discs. We also provide some discussion of potential directions for future research and treatments. PMID:25267492

Tsai, Tsung-Ting; Cheng, Chao-Min; Chen, Chien-Fu; Lai, Po-Liang

2014-01-01

170

Correlations between severity of clinical signs and histopathological changes in 60 dogs with spinal cord injury associated with acute thoracolumbar intervertebral disc disease.  

PubMed

The outcome of spinal surgery in dogs with absent voluntary motor function and nociception following intervertebral disc (IVD) herniation is highly variable, which likely attests to differences in the severity of spinal cord damage. This retrospective study evaluated the extent to which neurological signs correlated with histologically detected spinal cord damage in 60 dogs that were euthanased because of thoracolumbar IVD herniation. Clinical neurological grades correlated significantly with the extent of white matter damage (P<0.001). However, loss of nociception also occurred in 6/31 (19%) dogs with relatively mild histological changes. The duration of clinical signs, Schiff-Sherrington posture, loss of reflexes and pain on spinal palpation were not significantly associated with the severity of spinal cord damage. Although clinical-pathological correlation was generally good, some clinical signs frequently thought to indicate severe cord injury did not always correlate with the degree of cord damage, suggesting functional rather than structural impairment in some cases. PMID:23702280

Henke, D; Vandevelde, M; Doherr, M G; Stöckli, M; Forterre, F

2013-10-01

171

Counter-rotating accretion discs  

NASA Astrophysics Data System (ADS)

Counter-rotating discs can arise from the accretion of a counter-rotating gas cloud on to the surface of an existing corotating disc or from the counter-rotating gas moving radially inwards to the outer edge of an existing disc. At the interface, the two components mix to produce gas or plasma with zero net angular momentum which tends to free-fall towards the disc centre. We discuss high-resolution axisymmetric hydrodynamic simulations of viscous counter-rotating discs for the cases where the two components are vertically separated and radially separated. The viscosity is described by an isotropic ?-viscosity including all terms in the viscous stress tensor. For the vertically separated components, a shear layer forms between them and the middle part of this layer free-falls to the disc centre. The accretion rates are increased by factors of ˜102-104 over that for a conventional disc rotating in one direction with the same viscosity. The vertical width of the shear layer and the accretion rate are strongly dependent on the viscosity and the mass fraction of the counter-rotating gas. In the case of radially separated components where the inner disc corotates and the outer disc rotates in the opposite direction, a gap between the two components opens and closes quasi-periodically. The accretion rates are ?25 times larger than those for a disc rotating in one direction with the same viscosity.

Dyda, S.; Lovelace, R. V. E.; Ustyugova, G. V.; Romanova, M. M.; Koldoba, A. V.

2015-01-01

172

Enclosed rotary disc air pulser  

DOEpatents

An enclosed rotary disc air pulser for use with a solvent extraction pulse olumn includes a housing having inlet, exhaust and pulse leg ports, a shaft mounted in the housing and adapted for axial rotation therein, first and second disc members secured to the shaft within the housing in spaced relation to each other to define a chamber therebetween, the chamber being in communication with the pulse leg port, the first disc member located adjacent the inlet port, the second disc member being located adjacent the exhaust port, each disc member having a milled out portion, the disc members positioned on the shaft so that as the shaft rotates, the milled out portions permit alternative cyclical communication between the inlet port and the chamber and the exhaust port and the chamber.

Olson, A. L. (Idaho Falls, ID); Batcheller, Tom A. (Idaho Falls, ID); Rindfleisch, J. A. (Arco, ID); Morgan, John M. (Arco, ID)

1989-01-01

173

Cellulite: from standing fat herniation to hypodermal stretch marks.  

PubMed

There are glaring discrepancies in the microanatomical descriptions of cellulite in the literature. We revisited this common skin condition in women with a microscopic examination of 39 autopsy specimens. A control group consisted of 4 women and 11 men showing no evidence of cellulite. The lumpy aspect of the dermohypodermal interface appeared to represent a gender-linked characteristic of the thighs and buttocks without being a specific sign of cellulite. Incipient cellulite identified by the mattress phenomenon was related to the presence of focally enlarged fibrosclerotic strands partitioning the subcutis. Such strands possibly serve as a physiologic buttress against fat herniation limiting the outpouching of fat lobules on pinching the skin. These structures might represent a reactive process to sustained hypodermal pressure caused by fat accumulation. Full-blown cellulite likely represents subjugation of the hypertrophic response when connective tissue is overcome by progressive fat accumulation. Histologic aspects reminiscent of stretch marks are identified within the hypodermal strands, resulting in clinical skin dimpling. PMID:10698214

Piérard, G E; Nizet, J L; Piérard-Franchimont, C

2000-02-01

174

Enucleation/partial nephrectomy for large mixed epithelial stromal tumor and herniating into the pelvicalyceal system  

PubMed Central

Objectives: Mixed Epithelial and Stromal Tumor of the kidney is an adult renal neoplasm. It is mostly benign in nature. Typically it is composed of a mixture of epithelial and mesenchymal components. We hereby report on the feasibility of performing partial nephrectomy/enucleation for Huge Mixed Epithelial Stromal Tumor of the kidney without sacrificing the involved renal unit even in the tumors herniating into the collecting system. Methods: Two female patients on long term hormonal therapy developed large enhancing multiloculated and septated renal masses. Kidney mass size was 18.5 cms in one patient and 11.5 in the second. In one patient, the mass was herniating into the collecting system. Both patients had enucleation/partial nephrectomy. Results: Enucleation and partial nephrectomy were successfully performed in both patients. In the patient with the mass herniating into the collecting system, the horns of the mass herniating into the collecting system were easily enucleated with repair of the collecting system and salvage of the involved renal unit. Post op pathology revealed MEST in both patients. There were no intraoperative or postoperative complications. Conclusions: Enucleation and partial nephrectomy for huge MEST is feasible. Mixed Epithelial Stromal Tumor herniating into the pelvicalyceal system may not warrant nephroureterectomy as previously reported. PMID:25371624

Kamel, Mohamed H.; Davis, Rodney; Cox, Roni M.; Cole, Adam; Eltahawy, Ehab

2014-01-01

175

Intrathoracic omental herniation through the esophageal hiatus: report of a case.  

PubMed

We report herein an extremely rare case of intrathoracic omental herniation through the esophageal hiatus. In fact, according to our review of the literature, only eight other cases have been reported, most of which were misdiagnosed as mediastinal lipoma after being identified as an intrathoracic mass. We report herein the ninth case of intrathoracic omental herniation through the esophageal hiatus. A 54-year-old obese woman was admitted to our hospital for investigation of a chest roentgenographic abnormality. She was asymptomatic, and her physical examination and laboratory data were all within normal limits. Her chest X-ray demonstrated a large, sharply-defined mass, and a computed tomography scan of the thorax indicated a large mediastinal mass with fat density. A thoracotomy was performed under the diagnosis of a mediastinal lipoma which revealed an encapsulated fatty mass, 10x7.5x6 cm in size, that proved to be an omental herniation through the esophageal hiatus. There was no herniation of the stomach or intestines into the thorax. The esophageal hiatus was repaired after the omental mass and hernia sac had been resected. This case report serves to demonstrate that whenever a mass of fat density is recognized in the lower thorax, an omental herniation should be borne in mind as a possible differential diagnosis. PMID:10211566

Kato, N; Iwasaki, H; Rino, Y; Imada, T; Amano, T; Kondo, J

1999-01-01

176

Numbered nasal discs for waterfowl  

USGS Publications Warehouse

Numbered nasal discs were successfully used in studies requiring large numbers of individually marked waterfowl. The procedure for constructing these discs is outlined. Blue-winged teal (Anas discors) with 5/8-inch discs, and canvasback (Aythya valisineria) and redhead (A. americana) with 3/4-inch discs can be individually identified up to 50 and 80 yards, respectively, with a gunstock-mounted, 20-power spotting scope. The particular value of these markers is their durability, the number of combinations possible, and the apparent absence of behavioral or mortality influence among such species as the blue-winged teal.

Bartonek, J.C.; Dane, C.W.

1964-01-01

177

Conservative management of recurrent lumbar disk herniation with epidural fibrosis: a case report  

PubMed Central

Objective A retrospective case report of a 24-year-old man with recurrent lumbar disk herniation and epidural fibrosis is presented. Recurrent lumbar disk herniation and epidural fibrosis are common complications following lumbar diskectomy. Clinical Features A 24-year-old patient had a history of lumbar diskectomy and new onset of low back pain and radiculopathy. Magnetic resonance imaging revealed recurrent herniation at L5/S1, left nerve root displacement, and epidural fibrosis. Intervention and Outcomes The patient received a course of chiropractic care including lumbar spinal manipulation and rehabilitation exercises with documented subjective and objective functional and symptomatic improvement. Conclusion This case report describes chiropractic management including spinal manipulative therapy and rehabilitation exercises and subsequent objective and subjective functional and symptomatic improvement. PMID:23843756

Welk, Aaron B.; Werdehausen, Destiny N.; Kettner, Norman W.

2012-01-01

178

A ventral incisional hernia with herniation of the left hepatic lobe and review of the literature.  

PubMed

Ventral incisional hernias with hepatic herniation are extremely rare. Only six cases have been reported so far in the literature. We report a case of a ventral incisional hernia with hepatic herniation along with a review of the literature. A 70-year-old female patient with a history of coronary artery bypass graft surgery 6?months earlier, was admitted to our hospital with symptoms of epigastric swelling and discomfort for 3?months. On examination, she had a mild tender 5?cm×5?cm epigastric lump and was diagnosed as ventral incisional hernia. Contrast-enhanced CT of the abdomen revealed a ventral hernia with herniation of omentum and left hepatic lobe. The patient underwent onlay mesh repair and is asymptomatic at 1-month follow-up. There is a need for evaluation of risk factors for this type of ventral incisional hernia and to recognise it as a special entity. PMID:25631758

Neelamraju Lakshmi, Harish; Saini, Devendra; Om, Prabha; Bagree, Rajendra

2015-01-01

179

Dead discs, unstable discs and the stars they surround  

NASA Astrophysics Data System (ADS)

Strong stellar magnetic fields significantly alter the behaviour of surrounding accretion discs. Recent work has demonstrated that at low accretion rates a large amount of mass can remain confined in the disc, contrary to the standard assumption that the magnetic field will expel the disc in an outflow (the "propeller regime"). These "dead discs" often become unstable, causing cycles of accretion onto the central star. Here I present the main predictions of this model, and argue that it provides a good explanation for the peculiar behaviour seen in several accreting sources with strong magnetic fields. I will focus in particular on three accreting millisecond X-ray pulsars: SAX J1808.4-3658, NGC 6440 X-2 and IGR J00291+5934. These sources all show low-frequency quasi-periodic oscillations consistent with a variable accretion rate, as well as unusual outburst patterns that suggest gas is confined in the inner disc regions during quiescence.

D'Angelo, Caroline

2014-01-01

180

Mechanism of Action of Oxygen Ozone Therapy in the Treatment of Disc Herniation and Low Back Pain  

Microsoft Academic Search

\\u000a In the low back syndrome the pain has a multifactorial origin and ozone can surprisingly display a number of beneficial effects\\u000a ranging from the inhibition of inflammation, correction of ischemia and venous stasis, and finally inducing a reflex therapy\\u000a effect by stimulating anti-nociceptor analgesic mechanisms. The intradiscal and intramuscular injection of oxygen–ozone is\\u000a a successful approach comparable to other minimally

Emma Borrelli

181

Non traumatic liver herniation due to persistent cough mimicking a pulmonary mass  

PubMed Central

Background: Non traumatic liver herniation through a diaphragmatic defect is rare. Case Report: A 44 year old woman presented with lower lobe opacity at the right lung. Chest Computed tomography (CT) demonstrated a round tumor adjacent to the right diaphragm. Percutaneous needle biopsy revealed liver tissue. A small liver herniation through a diaphragmatic defect was detected in saggital and coronal CT views but no traumatic rupture of the diaphragm or endometriosis were documented. Conclusions: The patient suffered from gastroesophageal reflux disease and increased transdiaphragmatic pressure from paroxysmal cough due to aspirations may have provoked the diaphragmatic rupture. PMID:25031522

Pataka, A; Paspala, A; Sourla, E; Bagalas, V; Argyropoulou, P

2013-01-01

182

Region Specific Response of Intervertebral Disc Cells to Complex Dynamic Loading: An Organ Culture Study Using a Dynamic Torsion-Compression Bioreactor  

PubMed Central

The spine is routinely subjected to repetitive complex loading consisting of axial compression, torsion, flexion and extension. Mechanical loading is one of the important causes of spinal diseases, including disc herniation and disc degeneration. It is known that static and dynamic compression can lead to progressive disc degeneration, but little is known about the mechanobiology of the disc subjected to combined dynamic compression and torsion. Therefore, the purpose of this study was to compare the mechanobiology of the intervertebral disc when subjected to combined dynamic compression and axial torsion or pure dynamic compression or axial torsion using organ culture. We applied four different loading modalities [1. control: no loading (NL), 2. cyclic compression (CC), 3. cyclic torsion (CT), and 4. combined cyclic compression and torsion (CCT)] on bovine caudal disc explants using our custom made dynamic loading bioreactor for disc organ culture. Loads were applied for 8 h/day and continued for 14 days, all at a physiological magnitude and frequency. Our results provided strong evidence that complex loading induced a stronger degree of disc degeneration compared to one degree of freedom loading. In the CCT group, less than 10% nucleus pulposus (NP) cells survived the 14 days of loading, while cell viabilities were maintained above 70% in the NP of all the other three groups and in the annulus fibrosus (AF) of all the groups. Gene expression analysis revealed a strong up-regulation in matrix genes and matrix remodeling genes in the AF of the CCT group. Cell apoptotic activity and glycosaminoglycan content were also quantified but there were no statistically significant differences found. Cell morphology in the NP of the CCT was changed, as shown by histological evaluation. Our results stress the importance of complex loading on the initiation and progression of disc degeneration. PMID:24013824

Chan, Samantha C. W.; Walser, Jochen; Käppeli, Patrick; Shamsollahi, Mohammad Javad; Ferguson, Stephen J.; Gantenbein-Ritter, Benjamin

2013-01-01

183

Airway obstruction caused by endotracheal tube cuff herniation during creation of tracheal stoma.  

PubMed

We report an unusual case of airway obstruction caused by herniation of endotracheal tube (ETT) cuff in a 62-year-old male who underwent surgery for hypopharyngeal carcinoma. During the procedure of creating a tracheal stoma, a new oral ETT was inserted by the surgical team to the lower portion of the trachea through the cut opening to replace the old for ventilation and prevention of soiling of the airway. Upon resumption of surgical manipulation, right endobronchial intubation was disclosed. The ETT cuff was therefore repositioned and reinflated, but airway obstruction persisted in spite of tube obstruction being ruled out by successfully passing a suction catheter through the ETT. After deflating the cuff the obstruction was resolved, and ventilation was eased. Thus the ETT was replaced with another new one and careful scrutiny made after the event revealed a herniating cuff due to manufacturing defect. It was conceivable that endobronchial intubation with over-inflation of the tube cuff may cause cuff herniation, particularly when surgical manipulation was active at the adjacency, in spite of the use of a modern tube with low-pressure high-volume cuff. Performing the "cuff deflation test" is the simple way to diagnose cuff herniation. Awareness of this condition, especially when anesthesiologists lose direct control of the airway during such procedures is important because undesirable complications can be prevented through quick decision and action. PMID:15869007

Kao, Ming-Chang; Yu, Ya-Sheng; Liu, Hsu-Tang; Tsai, Shen-Kou; Lin, Su-Man; Huang, Ying-Che

2005-03-01

184

Idiopathic Ventral Spinal Cord Herniation: An Increasingly Recognized Cause of Thoracic Myelopathy  

PubMed Central

Idiopathic spinal cord herniation (ISCH), where a segment of the spinal cord has herniated through a ventral defect in the dura, is a rarely encountered cause of thoracic myelopathy. The purpose of our study was to increase the clinical awareness of this condition by presenting our experience with seven consecutive cases treated in our department since 2005. All the patients developed pronounced spastic paraparesis or Brown-Séquard syndrome for several years (mean, 4.7 years) prior to diagnosis. MRI was consistent with a transdural spinal cord herniation in the mid-thoracic region in all the cases. The patients underwent surgical reduction of the herniated spinal cord and closure of the dural defect using an artificial dural patch. At follow-up, three patients experienced considerable clinical improvement, one had slight improvement, one had transient improvement, and two were unchanged. Two of the four patients with sphincter dysfunction regained sphincter control. MRI showed realignment of the spinal cord in all the patients. ISCH is probably a more common cause of thoracic myelopathy than previously recognized. The patients usually develop progressive myelopathy for several years before the correct diagnosis is made. Early diagnosis is important in order to treat the patients before the myelopathy has become advanced. PMID:25336997

Berg-Johnsen, Jon; Ilstad, Eivind; Kolstad, Frode; Züchner, Mark; Sundseth, Jarle

2014-01-01

185

Abnormal anatomy of inferior orbital fissure and herniation of buccal fat pad.  

PubMed

The anatomy of the inferior orbital fissure has been well studied, and its reported dimensions vary little. It is encountered during exploration of the orbital floor and when possible is not disturbed. We describe a case of herniation of buccal fat through the inferior orbital fissure that was found during exploration and repair of the orbital floor. PMID:25451070

Aldridge, T; Thomson, A; Ilankovan, V

2015-01-01

186

Single Lung Retransplantation for Graft Infarction due to Herniation of Heart  

PubMed Central

A young woman with terminal respiratory failure due to idiopathic pulmonary hypertension underwent bilateral lung transplantation. The postoperative course was complicated by herniation of the heart through over the cut pericardial edge on left side leading to left-sided graft infarction requiring pneumonectomy. Unable to wean off mechanical ventilation, patient required lobar transplantation on the left side. PMID:25360412

Mohite, Prashant N.; Sabashnikov, Anton; Rao, Praveen; Zych, Bartlomiej; Simon, André

2013-01-01

187

Medical Information on Optical Disc*  

PubMed Central

Optical discs may permit a revolutionary change in the distribution and use of medical information. A single compact disc, similar in size to that used for digital audio recording, can contain over 500 million characters of information that is accessible by a Personal Computer. These discs can be manufactured at a cost lower than that of print on paper, at reasonable volumes. Software can provide the health care professional with nearly instantaneous access to the information. Thus, for the first time, the opportunity exists to have large local medical information collections. This paper describes an application of this technology in the field of Oncology.

Schipma, Peter B.; Cichocki, Edward M.; Ziemer, Susan M.

1987-01-01

188

Enlivening Physics, a Local Video Disc Project.  

ERIC Educational Resources Information Center

Describes how to make and use an inexpensive video disc of physics demonstrations. Discusses the background, production of the disc, subject of the disc including angular momentum, "monkey and the hunter" experiment, Doppler shift, pressure of a constant volume of gas thermometer, and wave effects, and using the disc in classroom. (YP)

McInerney, M.

1989-01-01

189

Tissue engineering: A live disc  

NASA Astrophysics Data System (ADS)

A material-cell hybrid device that mimics the anatomic shape of the intervertebral disc has been made and successfully implanted into mice to show that tissue engineering may, in the future, benefit sufferers from back pain.

Hukins, David W. L.

2005-12-01

190

Imaging diagnostics for transitional discs  

NASA Astrophysics Data System (ADS)

Transitional discs are a special type of protoplanetary disc, where planet formation is thought to be taking place. These objects feature characteristic inner cavities and/or gaps of a few tens of AUs in sub-millimetre images of the disc. This signature suggests a localised depletion of matter in the disc that could be caused by planet formation processes. However, recent observations have revealed differences in the structures imaged at different wavelengths in some of these discs. In this paper, we aim to explain these observational differences using self-consistent physical 2D hydrodynamical and dust evolution models of these objects, assuming their morphology is indeed generated by the presence of a planet. We use these models to derive the distribution of gas and dust in a theoretical planet-hosting disc for various planet masses and orbital separations. We then simulate observations of the emitted and scattered light from these models with Very Large Telescope (VLT)/SPHERE-ZIMPOL, Subaru/HiCIAO, VLT/VISIR, and ALMA. We do this by first computing the full resolution images of the models at different wavelengths and then simulating the observations while accounting for the characteristics of each particular instrument. The presence of the planet generates pressure bumps in the gas distribution of the disc, whose characteristics strongly depend on the planet mass and position. These bumps cause large grains to accumulate, while small grains are allowed into inner regions. This spatial differentiation of the grain sizes explains the differences in the observations, since different wavelengths and observing techniques trace different parts of the dust size distribution. Based on this effect, we conclude that the combination of visible/near-infrared polarimetric and sub-mm images is the best strategy to constrain the properties of the unseen planet responsible for the disc structure.

de Juan Ovelar, M.; Min, M.; Dominik, C.; Thalmann, C.; Pinilla, P.; Benisty, M.; Birnstiel, T.

2013-12-01

191

Large residual strains are present in the intervertebral disc annulus fibrosus in the unloaded state.  

PubMed

The intervertebral disc annulus fibrosus (AF) is subjected to high circumferential tensile stresses resulting from nucleus pulposus pressurisation under axial compression. In other pressure containing tissues, such as blood vessel walls, residual compressive stresses along the inside surface of the tissues without pressurisation reduce peak tensile stresses under pressurisation. This study hypothesised that similar patterns of residual stress exist in the annulus fibrosus. Accurate characterisation of residual stresses is essential for both the incorporation of nonlinear material descriptions into models of the disc as well as the design of effective annulus repair strategies. By imaging nine bovine caudal discs before and after the release of residual stresses via incision, we measured a mean residual stretch of 0.86 ± 0.13 at the inner AF and 1.02 ± 0.08 at the outer AF. These stretch values were used to calculate a gradient of residual stress ranging from -230 ± 22 kPa of compression at the inner AF to 54 ± 0.2 kPa of tension at the outer AF. Material models of AF have assumed that the AF was in a stress free reference state when there are no external loads. However, this study documents that there are large residual stresses in the AF even without external loads. The release of residual tension in the outer AF by herniation, needle injection or incisions makes closure difficult and may accelerate degeneration of the surrounding tissue. Retention of these residual stresses may be essential to maintaining disc mechanical function and to producing viable AF repair techniques. PMID:22342138

Michalek, A J; Gardner-Morse, M G; Iatridis, J C

2012-04-30

192

Adjacent segment degeneration after single-level anterior cervical decompression and fusion: Disc space distraction and its impact on clinical outcomes.  

PubMed

The purpose of this study was to find whether excessive distraction of the disc space for cage insertion was a risk factor for adjacent segment degeneration (ASD) after anterior cervical decompression and fusion (ACDF). One hundred and sixteen consecutive patients who underwent ACDF for single-level cervical disc herniation between June 2006 and November 2008 were retrospectively reviewed. Preoperative, postoperative and final follow-up disc height (DH), sagittal segmental alignment (SSA), and sagittal alignment of the cervical spine (SACS) were measured and compared between the ASD group and non-ASD group. In 116 patients, ASD was radiographically proven in 28 (24.1%) patients. The clinical outcomes were significantly improved compared to the preoperative scores in both groups. However, the postoperative and final follow-up DH of the ASD group were significantly higher than in the non-ASD group (p<0.05). In addition, the postoperative DH was significantly correlated with the postoperative or final follow-up SSA (p<0.05). However, postoperative DH was not found to significantly correlate with postoperative or final follow-up SACS (p=0.072 and p=0.096, respectively). Multivariate analysis showed that postoperative DH was the most significant risk factor for ASD. The clinical outcomes of ACDF for single-level degenerative cervical disc disease were satisfactory. Postoperative DH (the distracted distance) had the greatest impact on the incidence of ASD. Excessive disc space distraction is a considerable risk factor for the development of radiographic ASD. PMID:25487176

Li, Jia; Li, Yongqian; Kong, Fanlong; Zhang, Di; Zhang, Yingze; Shen, Yong

2014-12-01

193

21 CFR 872.3970 - Interarticular disc prosthesis (interpositional implant).  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Interarticular disc prosthesis (interpositional implant). 872... § 872.3970 Interarticular disc prosthesis (interpositional implant). (a) Identification. An interarticular disc prosthesis (interpositional implant) is...

2011-04-01

194

Hydrogel discs for digital microfluidics  

PubMed Central

Hydrogels are networks of hydrophilic polymer chains that are swollen with water, and they are useful for a wide range of applications because they provide stable niches for immobilizing proteins and cells. We report here the marriage of hydrogels with digital microfluidic devices. Until recently, digital microfluidics, a fluid handling technique in which discrete droplets are manipulated electromechanically on the surface of an array of electrodes, has been used only for homogeneous systems involving liquid reagents. Here, we demonstrate for the first time that the cylindrical hydrogel discs can be incorporated into digital microfluidic systems and that these discs can be systematically addressed by droplets of reagents. Droplet movement is observed to be unimpeded by interaction with the gel discs, and gel discs remain stationary when droplets pass through them. Analyte transport into gel discs is observed to be identical to diffusion in cases in which droplets are incubated with gels passively, but transport is enhanced when droplets are continually actuated through the gels. The system is useful for generating integrated enzymatic microreactors and for three-dimensional cell culture. This paper demonstrates a new combination of techniques for lab-on-a-chip systems which we propose will be useful for a wide range of applications. PMID:22662096

Fiddes, Lindsey K.; Luk, Vivienne N.; Au, Sam H.; Ng, Alphonsus H. C.; Luk, Victoria; Kumacheva, Eugenia; Wheeler, Aaron R.

2012-01-01

195

Perforation of the Pregnant Uterus during Laparoscopy for Suspected Internal Herniation after Gastric Bypass  

PubMed Central

We report perforations of a pregnant uterus during laparoscopy for suspected internal herniation after gastric bypass at 24 weeks of gestation. Abdominal access and gas insufflation were achieved by the use of a 12 mm optic trocar. An additional 5 mm trocar was positioned. The perforations were handled by suturing following laparotomy and mobilisation of the high located uterus. The uterine fundus was located in the subcostal area. Internal herniation was not verified. A cesarean section was made 6 weeks later due to acute low abdominal pain. During delivery the uterus was found normal. At 5 months of age the child has developed normal and seems healthy. Optical trocars should be used with caution for abdominal access during laparoscopy in pregnancy. Open access should probably be preferred in most cases. Accidental perforations of the uterine cavity may be handled in selected cases with simple closure even following the use of large trocars under close postoperative surveillance throughout the pregnancy. PMID:25548693

Harsem, N. K.; Røstad, S.; Mathisen, L. C.; Jacobsen, A. F.

2014-01-01

196

Acute gastric incarceration from thoracic herniation in pregnancy following laparoscopic antireflux surgery  

PubMed Central

Diaphragmatic hernia is a rare complication in pregnancy which due to misdiagnosis or management delays may be life-threatening. We report a case of a woman in the third trimester of pregnancy who presented with sudden onset of severe epigastric and thoracic pain radiating to the back. Earlier in the index pregnancy, she had undergone laparoscopic antireflux surgery (ARS) for a hiatus hernia because of severe gastro-oesophageal reflux. Owing to increasing epigastric pain a CT scan was carried out which diagnosed wrap disruption with gastric herniation into the thoracic cavity and threatened incarceration. This is, to our knowledge, the first report of severe adverse outcome after ARS during pregnancy, with acute intrathoracic gastric herniation. We recommend the avoidance of ARS in pregnancy, and the need to advise women undergoing ARS of the postoperative risks if pregnancy occurs within a few years of ARS. PMID:23378556

Brygger, Louise; Fristrup, Claus Wilki; Harbo, Frederik Severin Gråe; Jørgensen, Jan Stener

2013-01-01

197

Surgical technique for idiopathic spinal cord herniation: the Hammock method. Technical note.  

PubMed

Idiopathic spinal cord herniation is a rare disease, and surgical treatment is recommended for patients with motor deficits or progressive neurological symptoms. Surgery is performed to release and reposition the tethered spinal cord. In terms of repositioning and prevention of reherniation, various procedures have been proposed; enlargement of the ventral dural defect, primary closure of the defect with sutures, and insertion of a ventral patch for duraplasty. We treated 3 patients with idiopathic spinal cord herniation, using a ventral patch for duraplasty with an expanded polytetrafluoroethylene pericardial membrane (the Hammock method), and all 3 cases had good clinical outcome. The specific important technical aspects are described and illustrated. If this procedure is performed meticulously under the microscope by following the specific techniques, the Hammock method is safer and more effective for prevention of reherniation than simple enlargement of the dural defect. PMID:22522340

Akutsu, Hiroyoshi; Takada, Tomoya; Nakai, Kei; Tsuda, Kyoji; Sakane, Masataka; Aita, Ikuo; Matsumura, Akira

2012-01-01

198

Localized strain measurements of the intervertebral disc annulus during biaxial tensile testing.  

PubMed

Both inter-lamellar and intra-lamellar failures of the annulus have been described as potential modes of disc herniation. Attempts to characterize initial lamellar failure of the annulus have involved tensile testing of small tissue samples. The purpose of this study was to evaluate a method of measuring local surface strains through image analysis of a tensile test conducted on an isolated sample of annular tissue in order to enhance future studies of intervertebral disc failure. An annulus tissue sample was biaxial strained to 10%. High-resolution images captured the tissue surface throughout testing. Three test conditions were evaluated: submerged, non-submerged and marker. Surface strains were calculated for the two non-marker conditions based on motion of virtual tracking points. Tracking algorithm parameters (grid resolution and template size) were varied to determine the effect on estimated strains. Accuracy of point tracking was assessed through a comparison of the non-marker conditions to a condition involving markers placed on tissue surface. Grid resolution had a larger effect on local strain than template size. Average local strain error ranged from 3% to 9.25% and 0.1% to 2.0%, for the non-submerged and submerged conditions, respectively. Local strain estimation has a relatively high potential for error. Submerging the tissue provided superior strain estimates. PMID:25145810

Karakolis, Thomas; Callaghan, Jack P

2015-12-01

199

Blunt traumatic pericardial rupture and cardiac herniation with a penetrating twist: two case reports  

PubMed Central

Background Blunt Traumatic Pericardial Rupture (BTPR) with resulting cardiac herniation following chest trauma is an unusual and often fatal condition. Although there has been a multitude of case reports of this condition in past literature, the recurring theme is that of a missed injury. Its occurrence in severe blunt trauma is in the order of 0.4%. It is an injury that frequently results in pre/early hospital death and diagnosis at autopsy, probably owing to a combination of diagnostic difficulties, lack of familiarity and associated polytrauma. Of the patients who survive to hospital attendance, the mortality rate is in the order of 57-64%. Methods We present two survivors of BTPR and cardiac herniation, one with a delayed penetrating cardiac injury secondary to rib fractures. With these two cases and literature review, we hope to provide a greater awareness of this injury Conclusion BTPR and cardiac herniation is a complex and often fatal injury that usually presents under the umbrella of polytrauma. Clinicians must maintain a high index of suspicion for BTPR but, even then, the diagnosis is fraught with difficulty. In blunt chest trauma, patients should be considered high risk for BTPR when presenting with: Cardiovascular instability with no obvious cause Prominent or displaced cardiac silhouette and asymmetrical large volume pneumopericardium Potentially, with increasing awareness of the injury and improved use and availability of imaging modalities, the survival rates will improve and cardiac Herniation could even be considered the 5th H of reversible causes of blunt traumatic PEA arrest. PMID:20003497

2009-01-01

200

Bipolar duraplasty: a new technique for reducing transcranial cerebral herniation to allow for definitive cranioplasty.  

PubMed

Large, full-thickness calvarial defects cause increased brain tissue compliance, often resulting in transient, transcranial herniation in the setting of normotensive intracranial pressures. Cranioplasty serves to protect the cerebrum from external injury, provide an aesthetic contour, and alleviate neurological symptoms. Traditional options for management include head elevation, osmotic diuresis, mild hyperventilation, durotomy with closure following fluid evacuation, expansile cranioplasty, lobectomy, and procedure abortion with prolonged helmet therapy. Patients treated conservatively with helmet therapy commonly are noncompliant and sustain repeated minor trauma to unprotected cerebral contents. Furthermore, recent literature suggests that early cranioplasty may improve outcomes and reduce costs. The authors present a novel solution, bipolar duraplasty, which allows safe, transient reduction of normotensive parenchymal herniation using bipolar electrocautery. The dura of the herniated sac is cauterized using a low-set, bipolar current in a series of sagittal and coronal lines, resulting in immediate contraction and reduction allowing for definitive cranioplasty. This new method was used in a patient with a 30-cm(2) frontal bone defect following resection of a right falcine atypical meningioma. In this scenario, bipolar duraplasty was performed free of complication, and the patient has remained asymptomatic and greatly satisfied for 1 year since the procedure. This technique might facilitate earlier cranioplasty, could be applied to a wide range of patients, and may afford better neurological outcomes at a reduced cost. PMID:21854117

Gordon, Chad R; Swanson, Edward W; Westvik, Tormod; Yaremchuk, Michael J

2011-11-01

201

Computer animation via optical video disc  

E-print Network

This paper explores the notion of marrying two technologies: raster-scan computer animation and optical video discs. Animated sequences, generated at non real-time rates, then transfered to video disc, can be recalled under ...

Bender, Walter

1981-01-01

202

Hydrodynamic instability in eccentric astrophysical discs  

E-print Network

Eccentric Keplerian discs are believed to be unstable to three-dimensional hydrodynamical instabilities driven by the time-dependence of fluid properties around an orbit. These instabilities could lead to small-scale turbulence, and ultimately modify the global disc properties. We use a local model of an eccentric disc, derived in a companion paper, to compute the nonlinear vertical ("breathing mode") oscillations of the disc. We then analyse their linear stability to locally axisymmetric disturbances for any disc eccentricity and eccentricity gradient using a numerical Floquet method. In the limit of small departures from a circular reference orbit, the instability of an isothermal disc is explained analytically. We also study analytically the small-scale instability of an eccentric neutrally stratified polytropic disc with any polytropic index using a WKB approximation. We find that eccentric discs are generically unstable to the parametric excitation of small-scale inertial waves. The nonlinear evolution o...

Barker, Adrian J

2014-01-01

203

Disc Replacement for Low Back Pain  

MedlinePLUS

... for Low Back Pain Disc Replacement for Low Back Pain Page Content The evolution of disc replacement surgery may help select patients who have chronic low back pain. However, choosing which type of patient this procedure ...

204

Relatively uniform and accelerated degradation of pure iron coated with micro-patterned Au disc arrays.  

PubMed

Pure iron has been proven to be a potential biodegradable metal, but its degradation rate was too slow. To accelerate its biodegradation, micro-patterned Au disc films were deposited on the surface of pure iron by vacuum sputtering. The influence of Au disc films on the degradation of pure iron matrix in vitro was investigated in the present study. Electrochemical measurement results indicated that the corrosion current density of pure iron coated with micro-patterned Au disc films in Hank's solution was 4 times larger than that of the uncoated one, while the difference between the influences of micro-patterned Au discs with different diameters on the corrosion rate of pure iron was insignificant. Immersion test indicated that the corrosion depth for pure iron coated with Au disc films was about three times as that of bare pure iron. Both electrochemical test and immersion test revealed that the corrosion of pure iron matrix coated with Au disc array became more uniform. PMID:25579971

Cheng, J; Huang, T; Zheng, Y F

2015-03-01

205

Stable counteralignment of a circumbinary disc  

NASA Astrophysics Data System (ADS)

In general, when gas accretes on to a supermassive black hole (SMBH) binary, it is likely to have no prior knowledge of the binary angular momentum. Therefore, a circumbinary disc forms with a random inclination angle ? to the binary. It is known that for ? < 90° the disc will coalign with respect to the binary. If ? > 90°, the disc wholly counteraligns if it satisfies cos ? < -Jd/2Jb, where Jd and Jb are the magnitudes of the disc and binary angular momentum vectors, respectively. If, however, ? > 90° and this criterion is not satisfied, the same disc may counteralign its inner regions and, on longer time-scales, coalign its outer regions. I show that for typical disc parameters, describing an accretion event on to an SMBH binary, a misaligned circumbinary disc is likely to wholly coalign or counteralign with the binary plane. This is because the binary angular momentum dominates the disc angular momentum. However, with extreme parameters (binary mass ratio M2/M1? 1 or binary eccentricity e˜ 1), the same disc may simultaneously coalign and counteralign. It is known that coplanar prograde circumbinary discs are stable. I show that coplanar retrograde circumbinary discs are also stable. A chaotic accretion event on to an SMBH binary will therefore result in a coplanar circumbinary disc that is either prograde or retrograde with respect to the binary plane.

Nixon, Christopher J.

2012-07-01

206

Radiation hard vacuum switch  

DOEpatents

A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction.

Boettcher, Gordon E. (Albuquerque, NM)

1990-01-01

207

Electromagnetic Levitation of a Disc  

ERIC Educational Resources Information Center

This paper presents a teaching experiment that explores the levitation of a disc of ferromagnetic material in the presence of the magnetic field produced by a single electromagnet. In comparison to the classical experiment of the levitation of a sphere, the main advantage of the proposed laboratory bench is that the uniform magnetic field…

Valle, R.; Neves, F.; de Andrade, R., Jr.; Stephan, R. M.

2012-01-01

208

Intramural Sports Ultimate Disc "Hat"  

E-print Network

not provide health or accident insurance that covers intramural sports participants. The Intramural SportsIntramural Sports Ultimate Disc "Hat" Tournament Summer 2014 Intramural Sports Calendar of Events on the day of the tournament, teams will be drawn out of a hat and mixed for play. Sports and Special

Escher, Christine

209

Glycosaminoglycans of cat invertebral disc  

PubMed Central

The glycosaminoglycan contents of samples from cat intervertebral discs were examined by using cetylpyridinium chloride salt elution techniques. The values obtained related to the region of the vertebral column from which they were derived, to the area of the disc, and to water content. In wet tissue there was a significant difference between regions of the vertebral column and between areas of the disc and findings agreed with previous histological reports. The greater part of the glycosaminoglycans present consisted of chondroitin sulphate and dermatan sulphate with smaller amounts of hyaluronic acid; little keratan sulphate was found. The maximum amounts of chondroitin sulphate and dermatan sulphate occurred in the 0.5m-magnesium chloride fractions usually, but moved towards higher molar concentrations in samples derived from some sites, particularly in the lumbar region. Mean values for the water content of the areas of the disc were: nucleus pulposus, 82.4%; inner anulus, 65.6%; outer anulus, 50.5%. The water content was directly related to the amounts of chondroitin sulphate and dermatan sulphate. ImagesPLATE 1 PMID:4256903

Butler, W. F.; Wels, C. M.

1971-01-01

210

The Classical Vacuum.  

ERIC Educational Resources Information Center

The classical vacuum of physics is not empty, but contains a distinctive pattern of electromagnetic fields. Discovery of the vacuum, thermal spectrum, classical electron theory, zero-point spectrum, and effects of acceleration are discussed. Connection between thermal radiation and the classical vacuum reveals unexpected unity in the laws of…

Boyer, Timothy H.

1985-01-01

211

Evolution of linear warps in accretion discs and applications to protoplanetary discs in binaries  

NASA Astrophysics Data System (ADS)

Warped accretion discs are expected in many protostellar binary systems. In this paper, we study the long-term evolution of disc warp and precession for discs with dimensionless thickness H/r larger than their viscosity parameter ?, such that bending waves can propagate and dominate the warp evolution. For small warps, these discs undergo approximately rigid-body precession. We derive analytical expressions for the warp/twist profiles of the disc and the alignment time-scale for a variety of models. Applying our results to circumbinary discs, we find that these discs align with the orbital plane of the binary on a time-scale comparable to the global precession time of the disc, and typically much smaller than its viscous time-scale. We discuss the implications of our finding for the observations of misaligned circumbinary discs (such as KH 15D) and circumbinary planetary systems (such as Kepler-413); these observed misalignments provide useful constraints on the uncertain aspects of the disc warp theory. On the other hand, we find that circumstellar discs can maintain large misalignments with respect to the plane of the binary companion over their entire lifetime. We estimate that inclination angles larger than ˜20° can be maintained for typical disc parameters. Overall, our results suggest that while highly misaligned circumstellar discs in binaries are expected to be common, such misalignments should be rare for circumbinary discs. These expectations are consistent with current observations of protoplanetary discs and exoplanets in binaries, and can be tested with future observations.

Foucart, Francois; Lai, Dong

2014-12-01

212

Radiographic Markers of Femoroacetabular Impingement: Correlation of Herniation Pit and Femoral Bump with a Positive Cross-Over Ratio  

PubMed Central

Introduction. The goal of this study was to research the association of femoral bumps and herniation pits with the overlap-ratio of the cross-over sign. Methods. Pelvic X-rays and CT-scans of 2925 patients with good assessment of the anterior and the posterior acetabular wall and absence of neutral pelvic tilt were enrolled in the investigation. Finally pelvic X-rays were assessed for the presence of a positive cross-over sign, and CT-scans for a femoral bump or a herniation pit. Additionally, if a positive cross-over sign was discovered, the overlap-ratio was calculated. Results. A femoral bump was found in 53.3% (n = 1559), and a herniation pit in 27.2% (n = 796) of all hips. The overlap-ratio correlated positively with the presence of a femoral bump, while a negative correlation between the overlap-ratio and the presence of a herniation pit was found. The latter was significantly more often combined with a femoral bump than without. Conclusions. We detected an increased prevalence of femoral bump with increasing overlap-ratios of the cross-over sign indicating a relation to biomechanical stress. The observed decreased prevalence of herniation pits with increasing overlap-ratios could be explained by reduced mechanical stress due to nontightened iliofemoral ligament in the presence of retroversion of the acetabulum. PMID:24876972

Scheyerer, Max J.; Copeland, Carol E.; Stromberg, Jeffrey; Ruckstuhl, Thomas; Werner, Clément M. L.

2014-01-01

213

Numerical simulations of protostellar encounters II. Coplanar disc-disc encounters  

E-print Network

It is expected that an average protostar will undergo at least one impulsive interaction with a neighbouring protostar whilst a large fraction of its mass is still in a massive, extended disc. Such interactions must have a significant impact upon the evolution of the protostars and their discs. We have carried out a series of simulations of coplanar encounters between two stars, each possessing a massive circumstellar disc, using an SPH code that models gravitational, hydrodynamic and viscous forces. We find that during a coplanar encounter, disc material is swept up into a shock layer between the two interacting stars, and the layer then fragments to produce new protostellar condensations. The truncated remains of the discs may subsequently fragment; and the outer regions of the discs may be thrown off to form circumbinary disc-like structures around the stars. Thus coplanar disc-disc encounters lead efficiently to the formation of multiple star systems and small-N clusters.

S. J. Watkins; A. S. Bhattal; H. M. J. Boffin; N. Francis; A. P. Whitworth

1998-05-28

214

The pathophysiology, classification, treatment, and prognosis of a spontaneous thoracic spinal cord herniation: A case study with literature review  

PubMed Central

Background: Spinal cord herniation was first described in 1974. It generally occurs in middle-aged adults in the thoracic spine. Symptoms typically include back pain and progressive paraparesis characterized by Brown-Séquard syndrome. Surgical reduction of the hernia improves the attendant symptoms and signs, even in patients with longstanding deficits. Case Description: A 66-year-old female with back pain for 7 years, accompanied by paresthesias and a progressive paraparesis, underwent a thoracic MRI which documented a ventral spinal cord herniation at the T4 level. Following a laminectomy, with reduction of the hernia and ventral dural repair, the patient improved. Conclusion: Herniation of the thoracic cord, documented on MR, may produce symptomatic paraparesis which may resolve following laminectomy with ventral dural repair.

De Souza, Rodrigo Becco; De Aguiar, Guilherme Brasileiro; Daniel, Jefferson Walter; Veiga, José Carlos Esteves

2014-01-01

215

Laminated composite disc flywheel development  

NASA Astrophysics Data System (ADS)

A flywheel concept for an electric powered vehicle uses a laminated disc and a filament wound outer ring assembled with an interference fit between these two components. The laminated, central disc is made of S2-glass-epoxy and the outer ring is filament-wound graphite-epoxy. Projections for this particular flywheel design indicate that it will be both practical and relatively inexpensive to produce, and that it will have a high energy density capacity. Two hybrid composite flywheels of 37 cm O.D. were successfully assembled. The spin test data are summarized, the nondestructive test dat are discussed and the fabrication techniques developed for the hybrid flywheel assembly are described.

Nimmer, R. P.; Torossian, K.; Hickey, J.

1980-02-01

216

Ptolemy relations for punctured discs  

E-print Network

We construct frieze patterns of type D_N with entries which are numbers of matchings between vertices and triangles of corresponding triangulations of a punctured disc. For triangulations corresponding to orientations of the Dynkin diagram of type D_N, we show that the numbers in the pattern can be interpreted as specialisations of cluster variables in the corresponding Fomin-Zelevinsky cluster algebra.

Baur, Karin

2007-01-01

217

Thermal cracking in disc brakes  

Microsoft Academic Search

Disc brakes are exposed to large thermal stresses during routine braking and extraordinary thermal stresses during hard braking. High-g decelerations typical of passenger vehicles are known to generate temperatures as high as 900°C in a fraction of a second. These large temperature excursions have two possible outcomes: thermal shock that generates surface cracks; and\\/or large amounts of plastic deformation in

Thomas J. Mackin; Steven C. Noe; K. J. Ball; B. C. Bedell; D. P. Bim-Merle; M. C. Bingaman; D. M. Bomleny; G. J. Chemlir; D. B. Clayton; H. A. Evans; R. Gau; J. L. Hart; J. S. Karney; B. P. Kiple; R. C. Kaluga; P. Kung; A. K. Law; D. Lim; R. C. Merema; B. M. Miller; T. R. Miller; T. J. Nielson; T. M. O'Shea; M. T. Olson; H. A. Padilla; B. W. Penner; C. Penny; R. P. Peterson; V. C. Polidoro; A. Raghu; B. R. Resor; B. J. Robinson; D. Schambach; B. D. Snyder; E. Tom; R. R. Tschantz; B. M. Walker; K. E. Wasielewski; T. R. Webb; S. A. Wise; R. S. Yang; R. S. Zimmerman

2002-01-01

218

Thin, thick and dark discs in LCDM  

E-print Network

In a LCDM cosmology, the Milky Way accretes satellites into the stellar disc. We use cosmological simulations to assess the frequency of near disc plane and higher inclination accretion events, and collisionless simulations of satellite mergers to quantify the final state of the accreted material and the effect on the thin disc. On average, a Milky Way-sized galaxy has 3 subhalos with vmax>80km/s; 7 with vmax>60km/s; and 15 with vmax>40km/s merge at redshift z>1. Assuming isotropic accretion, a third of these merge at an impact angle 20 degrees) are twice as likely as low inclination ones. These lead to structures that closely resemble the recently discovered inner/outer stellar halos. They also do more damage to the Milky Way stellar disc creating a more pronounced flare, and warp; both long-lived and consistent with current observations. The most massive mergers (vmax>80km/s) heat the thin disc enough to produce a thick disc. These heated thin disc stars are essential for obtaining a thick disc as massive as that seen in the Milky Way; they likely comprise some ~50-90% of the thick disc stars. The Milky Way thin disc must reform from fresh gas after z=1 [abridged].

J. I. Read; G. Lake; O. Agertz; Victor P. Debattista

2008-03-19

219

Intervertebral disc: anatomy-physiology-pathophysiology-treatment.  

PubMed

This review article describes anatomy, physiology, pathophysiology and treatment of intervertebral disc. The intervertebral discs lie between the vertebral bodies, linking them together. The components of the disc are nucleus pulposus, annulus fibrosus and cartilagenous end-plates. The blood supply to the disc is only to the cartilagenous end-plates. The nerve supply is basically through the sinovertebral nerve. Biochemically, the important constituents of the disc are collagen fibers, elastin fibers and aggrecan. As the disc ages, degeneration occurs, osmotic pressure is lost in the nucleus, dehydration occurs, and the disc loses its height. During these changes, nociceptive nuclear material tracks and leaks through the outer rim of the annulus. This is the main source of discogenic pain. While this is occurring, the degenerative disc, having lost its height, effects the structures close by, such as ligamentum flavum, facet joints, and the shape of the neural foramina. This is the main cause of spinal stenosis and radicular pain due to the disc degeneration in the aged populations. Diagnosis is done by a strict protocol and treatment options are described in this review. The rationale for new therapies are to substitute the biochemical constituents, or augment nucleus pulposus or regenerate cartilaginous end-plate or finally artificial disc implantation.. PMID:18211591

Raj, P Prithvi

2008-01-01

220

Traumatic Right Diaphragmatic Rupture Combined with Avulsion of the Right Kidney and Herniation of the Liver into the Thorax  

PubMed Central

Right-sided diaphragmatic rupture is less common and more difficult to diagnose than left-sided lesion. It is rarely combined with the herniation of the abdominal organs into the thorax. High level of suspicion is the key to early diagnosis, and a delay in diagnosis is implicated with a considerable risk of mortality and morbidity. We experienced a case of right-sided diaphragmatic rupture combined with complete avulsion of the right kidney and herniation of the liver into the thoracic cavity. PMID:22263130

Kim, Chong Wook; Park, Chong-Bin; Ahn, Jae Hong

2011-01-01

221

Spontaneous Spinal Cord Herniation: MR Imaging and Clinical Features in Six Cases  

Microsoft Academic Search

\\u000a Abstract\\u000a \\u000a \\u000a Background and Purpose:\\u000a   Spontaneous spinal cord herniation (SSCH) is a rare but important differential diagnosis of spinal cord disorder. The aim\\u000a of this study was to evaluate the topography and lesion pattern in six patients with SSCH by magnetic resonance imaging (MRI)\\u000a and their correlation with clinical symptoms.\\u000a \\u000a \\u000a \\u000a \\u000a Material and Methods:\\u000a   MRI was evaluated according to intramedullary hyperintense signal

Stella Blasel; Elke Hattingen; Horst Baas; Friedhelm Zanella; Stefan Weidauer

2008-01-01

222

Management of Cerebellar Tonsillar Herniation following Lumbar Puncture in Idiopathic Intracranial Hypertension  

PubMed Central

Lumbar puncture is performed routinely for diagnostic and therapeutic purposes in idiopathic intracranial hypertension, despite lumbar puncture being classically contraindicated in the setting of raised intracranial pressure. We report the case of a 30-year-old female with known idiopathic intracranial hypertension who had cerebellar tonsillar herniation following therapeutic lumbar puncture. Management followed guidelines regarding treatment of traumatic intracranial hypertension, including rescue decompressive craniectomy. We hypothesize that the changes in brain compliance that are thought to occur in the setting of idiopathic intracranial hypertension are protective against further neuronal injury due to axonal stretch following decompressive craniectomy.

Hoffman, Kenneth R.; Chan, Sean W.; Hughes, Andrew R.; Halcrow, Stephen J.

2015-01-01

223

Vacuum pump aids ejectors  

SciTech Connect

The steam ejector/vacuum pump hybrid system has been operating satisfactorily since the summer of 1981. This system has essentially been as troublefree as the all-ejector system and, of course, has provided a substantial cost savings. Construction is currently under way to convert the vacuum system of another crude still which is equipped with steam ejectors and barometric condensers to the hybrid system of steam ejectors, surface condensers, and vacuum pumps. This current project is even more financially attractive because it allows a dirty water cooling tower which serves the barometric condensers to be shut down. Providing a vacuum for crude distillation vacuum towers with this hybrid system is by no means the only application of this technique. Any vacuum system consisting of all steam ejectors would be a candidate for this hybrid system and the resulting savings in energy.

Nelson, R.E.

1982-12-01

224

A method for quantitative measurement of lumbar intervertebral disc structures: an intra- and inter-rater agreement and reliability study  

PubMed Central

Background There is a shortage of agreement studies relevant for measuring changes over time in lumbar intervertebral disc structures. The objectives of this study were: 1) to develop a method for measurement of intervertebral disc height, anterior and posterior disc material and dural sac diameter using MRI, 2) to evaluate intra- and inter-rater agreement and reliability for the measurements included, and 3) to identify factors compromising agreement. Methods Measurements were performed on MRIs from 16 people with and 16 without lumbar disc herniation, purposefully chosen to represent all possible disc contours among participants in a general population study cohort. Using the new method, MRIs were measured twice by one rater and once by a second rater. Agreement on the sagittal start- and end-slice was evaluated using weighted Kappa. Length and volume measurements were conducted on available slices between intervertebral foramens, and cross-sectional areas (CSA) were calculated from length measurements and slice thickness. Results were reported as Bland and Altman’s limits of agreement (LOA) and intraclass correlation coefficients (ICC). Results Weighted Kappa (Kw (95% CI)) for start- and end-slice were: intra-: 0.82(0.60;0.97) & 0.71(0.43;0.93); inter-rater: 0.56(0.29;0.78) & 0.60(0.35;0.81). For length measurements, LOA ranged from [?1.0;1.0] mm to [?2.0;2.3] mm for intra-; and from [?1.1; 1.4] mm to [?2.6;2.0] mm for inter-rater. For volume measurements, LOA ranged from [?293;199] mm3 to [?582;382] mm3 for intra-, and from [?17;801] mm3 to [?450;713] mm3 for inter-rater. For CSAs, LOA ranged between [?21.3; 18.8] mm2 and [?31.2; 43.7] mm2 for intra-, and between [?10.8; 16.4] mm2 and [?64.6; 27.1] mm2 for inter-rater. In general, LOA as a proportion of mean values gradually decreased with increasing size of the measured structures. Agreement was compromised by difficulties in identifying the vertebral corners, the anterior and posterior boundaries of the intervertebral disc and the dural sac posterior boundary. With two exceptions, ICCs were above 0.81. Conclusions Length measurements and calculated CSAs of disc morphology and dural sac diameter from MRIs showed acceptable intra- and inter-rater agreement and reliability. However, caution should be taken when measuring very small structures and defining anatomical landmarks. PMID:23953197

2013-01-01

225

Vacuum probe surface sampler  

NASA Technical Reports Server (NTRS)

A vacuum probe surface sampler is described for rapidly sampling relatively large surface areas which possess relatively light loading densities of micro-organism, drug particles or the like. A vacuum head with a hollow handle connected to a suitable vacuum source is frictionally attached to a cone assembly terminating in a flared tip adapted to be passed over the surface to be sampled. A fine mesh screen carried by the vacuum head provides support for a membrane filter which collects the microorganisms or other particles. The head assembly is easily removed from the cone assembly without contacting the cone assembly with human hands.

Zahlava, B. A. (inventor)

1973-01-01

226

NSLS II Vacuum System  

SciTech Connect

National Synchrotron Light Source II, being constructed at Brookhaven, is a 3-GeV, 500 mA, 3rd generation synchrotron radiation facility with ultra low emittance electron beams. The storage ring vacuum system has a circumference of 792 m and consists of over 250 vacuum chambers with a simulated average operating pressure of less than 1 x 10{sup -9} mbar. A summary of the update design of the vacuum system including girder supports of the chambers, gauges, vacuum pumps, bellows, beam position monitors and simulation of the average pressure will be shown. A brief description of the techniques and procedures for cleaning and mounting the chambers are given.

Ferreira, M.; Doom, L.; Hseuh, H.; Longo, C.; Settepani, P.; Wilson, K.; Hu, J.

2009-09-13

227

Rossby wave instability in astrophysical discs  

NASA Astrophysics Data System (ADS)

A brief review is given of the Rossby wave instability in astrophysical discs. In non-self-gravitating discs, around for example a newly forming stars, the instability can be triggered by an axisymmetric bump at some radius r0 in the disc surface mass-density. It gives rise to exponentially growing non-axisymmetric perturbation (\\propto \\exp \\,({ { i}}m\\phi ) , m = 1,2,…) in the vicinity of r0 consisting of anticyclonic vortices. These vortices are regions of high pressure and consequently act to trap dust particles which in turn can facilitate planetesimal growth in proto-planetary discs. The Rossby vortices in the discs around stars and black holes may cause the observed quasi-periodic modulations of the disc's thermal emission.

Lovelace, R. V. E.; Romanova, M. M.

2014-08-01

228

Stellar capture by an accretion disc  

E-print Network

Long-term evolution of a stellar orbit captured by a massive galactic center via successive interactions with an accretion disc has been examined. An analytical solution describing evolution of the stellar orbital parameters during the initial stage of the capture was found. Our results are applicable to thin Keplerian discs with an arbitrary radial distribution of density and rather general prescription for the star-disc interaction. Temporal evolution is given in the form of quadrature which can be carried out numerically.

D. Vokrouhlicky; V. Karas

1997-10-15

229

Close-packing of growing discs  

SciTech Connect

Spiral lattices are derived by allowing growing discs to aggregate under a close-packing rule. Both Fibonacci and Lucas numbers of visible spirals arise naturally, dependent only on the choice of growth centre. Both the rate of convergence towards an ideal spiral, and chirality, are determined by the initial placement of the first few discs (initial conditions). Thus the appearance of spiral packings is no more or less mysterious than the appearance of hexagonal packed arrays of equal discs.

Bursill, L.A.; Xudong, F. (Melbourne Univ., Parkville (Australia). School of Physics)

1988-12-01

230

Close-Packing of Growing Discs  

NASA Astrophysics Data System (ADS)

Spiral lattices are derived by allowing growing discs to aggregate under a close-packing rule. Both Fibonacci and Lucas numbers of visible spirals arise naturally, dependent only on the choice of growth centre. Both the rate of convergence towards an ideal spiral, and chirality, are determined by the initial placement of the first few discs (initial conditions). Thus the appearance of spiral packings is no more or less mysterious than the appearance of hexagonal packed arrays of equal discs.

Bursill, L. A.; Xudong, Fan

231

Turbulent drag reduction through oscillating discs  

NASA Astrophysics Data System (ADS)

The changes of a turbulent channel flow subjected to oscillations of wall flush-mounted rigid discs are studied by means of direct numerical simulations. The Reynolds number is $R_\\tau$=$180$, based on the friction velocity of the stationary-wall case and the half channel height. The primary effect of the wall forcing is the sustained reduction of wall-shear stress, which reaches a maximum of 20%. A parametric study on the disc diameter, maximum tip velocity, and oscillation period is presented, with the aim to identify the optimal parameters which guarantee maximum drag reduction and maximum net energy saving, computed by taking into account the power spent to actuate the discs. This may be positive and reaches 6%. The Rosenblat viscous pump flow is used to predict the power spent for disc motion in the turbulent channel flow and to estimate localized and transient regions over the disc surface subjected to the turbulent regenerative braking effect, for which the wall turbulence exerts work on the discs. The FIK identity is employed to show that the wall-friction reduction is due to two distinguished effects. One effect is linked to the direct shearing action of the near-wall oscillating disc boundary layer on the wall turbulence, which causes the attenuation of the turbulent Reynolds stresses. The other effect is due the additional disc-flow Reynolds stresses produced by the inter-disc structures. The contribution to drag reduction due to turbulent Reynolds stress attenuation depends on the penetration thickness of the disc-flow boundary layer, while the contribution due to the elongated structures scales linearly with a simple function of the maximum tip velocity and oscillation period for the largest disc diameter tested, a result suggested by the Rosenblat flow solution. A brief discussion on the future applicability of the oscillating-disc technique is also presented.

Wise, Daniel J.; Ricco, Pierre

2014-05-01

232

Disc repositioning: does it really work?  

PubMed

Although limited, there is evidence to support the assumption that temporomandibular joint (TMJ) articular disc repositioning indeed works; to date, there is no evidence that TMJ articular disc repositioning does not work. Despite the controversy among professionals in private practice and academia, TMJ articular disc repositioning is a procedure based on (still limited) evidence; the opposition is based solely on clinical preference and influenced by the ability to perform it or not. PMID:25483446

Gonçalves, João Roberto; Cassano, Daniel Serra; Rezende, Luciano; Wolford, Larry M

2015-02-01

233

HD 98800: A most unusual debris disc  

E-print Network

The dynamics of planetesimals in the circumbinary debris disc of the quadruple star system HD 98800 are investigated. Evolving a spherical shell of test particles from a million years ago to the present day indicates that both coplanar and retrograde warped discs could exist, as well as a high inclination halo of material. Significant gaps are seen in the discs, as well as unexpected regions of stability due to the retrograde nature of the stellar orbits. Despite a viewing angle almost perpendicular to the direction of the warp of the planetesimal disc it is still intersected by the line of sight for eccentricities of the outer orbit of 0.5 or less.

P. E. Verrier; N. W. Evans

2008-07-31

234

On the evolution of the protolunar disc.  

PubMed

The structure and viscous evolution of a post-impact, protolunar disc is examined. The equations for a silicate disc in two-phase (vapour-liquid) equilibrium are employed to derive an analytical solution to vertical structure. Both a vertically mixed phase disc and a stratified disc, where a magma layer exists in the mid-plane surrounded by a vapour reservoir, are considered. The former largely reproduces the low gas mass fraction, x?1, profiles of the disc described in earlier literature that proposed that the disc would hover on the brink of gravitational instability. In the latter, the vapour layer has x?1 and is generally gravitationally stable, while the magma layer is vigorously unstable. The viscous evolution of the stratified model is then explored. Initially, the disc quickly settles to a quasi-steady state with a vapour reservoir containing the majority of the disc mass. The magma layer viscously spreads on a time scale of approximately 3-4 years, during which vapour continuously condenses into droplets that settle to the mid-plane, maintaining the magma surface density in spite of disc spreading. Material flowing inwards is accreted by the Earth; material flowing outwards past the Roche boundary can become incorporated into accreting moonlets. This evolution persists until the vapour reservoir is depleted in approximately 50-100 years, depending on its initial mass. PMID:25114314

Ward, William R

2014-09-13

235

Enhancing tissue repair in annulus fibrosus defects of the intervertebral disc: analysis of a bio-integrative annulus implant in an in-vivo ovine model.  

PubMed

Annulus fibrosus repair techniques for the intervertebral disc (IVD) address the unsolved problem of reherniation after IVD herniation and might facilitate the development of nucleus pulposus replacement techniques for IVD diseases. This study investigates the suitability of a bio-integrative annulus implant.Standardized box defects were applied to the annulus L3/4 and L4/5 of 16 sheep, followed by randomized insertion of the textile polyglycolic acid/polyvinylidene fluoride annulus implant in one of the defects. Explantation was conducted after 2, 6 and 12 weeks, followed by provocative pressure testing and histological analysis. At 2 weeks' follow-up, all specimens of the control defect group demonstrated uncontained herniated nucleus pulposus tissue in the annulus defects. For the treated specimens, the annulus implant consistently provided an effective barrier for herniating nucleus pulposus tissue, with no implant dislocation at all time-points. After 2 weeks, a homogeneous cell infiltration of the annulus implant was observed, leading to a progressive directional matrix build-up. Repair tissue thickness was significantly stronger with the annulus implant at all follow-ups (p < 0.01). No pronounced foreign body reaction and no difference in the amount of supra-annular scar tissue over the defect sites were observed. The implantation procedure inflicted annulus damage adjacent to the defect. At later time-points, however, no difference in comparison with the control defect group was evident. The investigated biointegrative annulus implant showed promising results with regard to biointegration, enhancement of repair tissue and function as a mechanical barrier in an ovine model. © 2013 The Authors. Journal of Tissue Engineering and Regenerative Medicine published by John Wiley & Sons, Ltd. PMID:24227682

Hegewald, Aldemar Andres; Medved, Fabian; Feng, Daxiong; Tsagogiorgas, Charalambos; Beierfuß, Anja; Schindler, Genevieve Ama Kyremaa; Trunk, Marcus; Kaps, Christian; Mern, Demissew Shenegelegn; Thomé, Claudius

2013-11-12

236

Vacuum Vessel Remote Handling  

E-print Network

FIRE Vacuum Vessel and Remote Handling Overview B. Nelson, T. Burgess, T. Brown, H-M Fan, G. Jones · Vacuum Vessel - Design requirements - Design concept and features - Analysis to date - Status and summary Replacement Time Estimates - Balance of RH Equipment · Design and analysis are consistent with pre

237

The ultimate vacuum  

Microsoft Academic Search

The ultimate vacuum, defined as the lowest pressure that can be produced and measured reproducibly in a vacuum system at room temperature, has decreased by a factor of about 1014 since the first measurement of sub-atmospheric pressure by Robert Boyle in about 1660. A brief historical review is presented of the key advances that caused significant decreases in the ultimate

P. A. Redhead

1999-01-01

238

Microfabricated triggered vacuum switch  

DOEpatents

A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

Roesler, Alexander W. (Tijeras, NM); Schare, Joshua M. (Albuquerque, NM); Bunch, Kyle (Albuquerque, NM)

2010-05-11

239

ELETTRA vacuum system  

NASA Astrophysics Data System (ADS)

A status report of the vacuum system of ELETTRA, the 2 GeV, 400 mA light source under construction in Trieste, will be described. The Vacuum project, presented at ``Synchrotron Radiation Vacuum Workshop'' at Riken (Japan 22-24 March 1990) and more recently at EVC-2, the European Vacuum Conference at Trieste (Italy 21-26 May 1990), is now in the phase of testing a prototype sector, which is 1/24 of the ring circumference. Details and some technological aspects of the fabrication will be reviewed together with the vacuum performances. Results of laboratory experiments on components, standard or not, allowed us to finalize the main choices in light of the general philosophy of the project and will be properly summarized.

Bernardini, M.

1991-08-01

240

[Computed tomography in the diagnosis of recurrent herniated disks following prior lumbar intervertebral disk operations].  

PubMed

20 patients with recurrent symptoms following operations for disc prolapse and resistant to treatment were studied by CT, using plain and enhanced images. The results have been analysed. In 10 patients a recurrence of disc prolapse was diagnosed, and this was confirmed surgically in 8 cases. In 2 patients there was epidural scarring. The findings indicate that differential diagnosis between scarring and recurring prolapse can be accurately made by this technique. PMID:1596545

Burval, S; Nekula, J; Vaverka, M; Velísková, J

1992-05-01

241

Clinical characteristics of nonglaucomatous optic disc cupping  

PubMed Central

Pathological optic disc cupping (ODC) is predominantly referred to as glaucoma; however, it is not only glaucoma that leads to pathological optic disc excavation. A number of other nonglaucomatous diseases also result in optic atrophy and excavation of the optic disc. Therefore, in the present study, the etiology of nonglaucomatous optic disc cupping (NGODC) was analyzed and differentiated from glaucomatous optic disc cupping (GODC). The morphology and clinical data of 19 eyes, from 12 patients exhibiting NGODC, were analyzed. Of the 12 cases, none were diagnosed with glaucoma, four presented with optic neuritis, one with Devic’s disease, one with Leber’s hereditary optic neuropathy, two with pituitary adenoma, one with basal ganglia cerebral hemorrhage, one with cilioretinal artery occlusion associated with central retinal vein occlusion, one with central retinal artery occlusion and the remaining patient exhibited optic nerve injuries. The key features that differentiated NGODC from GODC were the color of the optic disc rim and the correlation between visual field defects and the disc appearance. The focally notched disc also aided in distinguishing between the two disorders. The results of the present study indicated that it is critical to acknowledge that nonglaucomatous diseases also lead to ODC and that distinguishing between them is necessary. PMID:24669265

ZHANG, YI-XIN; HUANG, HOU-BIN; WEI, SHI-HUI

2014-01-01

242

Clinical characteristics of nonglaucomatous optic disc cupping.  

PubMed

Pathological optic disc cupping (ODC) is predominantly referred to as glaucoma; however, it is not only glaucoma that leads to pathological optic disc excavation. A number of other nonglaucomatous diseases also result in optic atrophy and excavation of the optic disc. Therefore, in the present study, the etiology of nonglaucomatous optic disc cupping (NGODC) was analyzed and differentiated from glaucomatous optic disc cupping (GODC). The morphology and clinical data of 19 eyes, from 12 patients exhibiting NGODC, were analyzed. Of the 12 cases, none were diagnosed with glaucoma, four presented with optic neuritis, one with Devic's disease, one with Leber's hereditary optic neuropathy, two with pituitary adenoma, one with basal ganglia cerebral hemorrhage, one with cilioretinal artery occlusion associated with central retinal vein occlusion, one with central retinal artery occlusion and the remaining patient exhibited optic nerve injuries. The key features that differentiated NGODC from GODC were the color of the optic disc rim and the correlation between visual field defects and the disc appearance. The focally notched disc also aided in distinguishing between the two disorders. The results of the present study indicated that it is critical to acknowledge that nonglaucomatous diseases also lead to ODC and that distinguishing between them is necessary. PMID:24669265

Zhang, Yi-Xin; Huang, Hou-Bin; Wei, Shi-Hui

2014-04-01

243

Measuring the wear of diamond discs  

Microsoft Academic Search

Before grinding, the face of the pneumatic instrument's measuring nozzle 1 is set opposite the working surface 2 of the diamond disc 3 and the face of the nozzle 6 opposite the surface 5, which forms part of the disc's body and is located near its working surface and, therefore, is displaced owing to thermal expansion together with the latter

E. S. Zemlyanskii

1974-01-01

244

Counterrotating stars in simulated galaxy discs  

NASA Astrophysics Data System (ADS)

Counterrotating stars in disc galaxies are a puzzling dynamical feature whose origin has been ascribed to either satellite accretion events or to disc instabilities triggered by deviations from axisymmetry. We use a cosmological simulation of the formation of a disc galaxy to show that counterrotating stellar disc components may arise naturally in hierarchically clustering scenarios even in the absence of merging. The simulated disc galaxy consists of two coplanar, overlapping stellar components with opposite spins: an inner counterrotating bar-like structure made up mostly of old stars surrounded by an extended, rotationally supported disc of younger stars. The opposite-spin components originate from material accreted from two distinct filamentary structures which at turn around, when their net spin is acquired, intersect delineating a `V'-like structure. Each filament torques the other in opposite directions; the filament that first drains into the galaxy forms the inner counterrotating bar, while material accreted from the other filament forms the outer disc. Mergers do not play a substantial role and most stars in the galaxy are formed in situ; only 9 per cent of all stars are contributed by accretion events. The formation scenario we describe here implies a significant age difference between the co- and counterrotating components, which may be used to discriminate between competing scenarios for the origin of counterrotating stars in disc galaxies.

Algorry, David G.; Navarro, Julio F.; Abadi, Mario G.; Sales, Laura V.; Steinmetz, Matthias; Piontek, Franziska

2014-02-01

245

Dependence of optic disc parameters on disc area according to Heidelberg Retina Tomograph: Part II.  

NASA Astrophysics Data System (ADS)

With the help of Heidelberg Retina Tomograph (HRT-II) optic disc parameters in 211 eyes of 115 healthy patients with refraction Em +/- 3,0 D and 96 eyes of 72 patients with myopia 3,5-14,0 D without any signs of glaucoma were studied. Analysis of optic disc parameters were carried out in 5 groups of patients according to disc area: less than 1,5 mm2, 1,5- 2,5 mm2, 2,5-3,0 mm2, 3,0-3,5 mm2 and more than 3,5 mm2. An accurate depending on disc area was revealed for all optic disc parameters in all sectors, which was manifested by increasing cup disc and rim disc (area and volume) and other parameters. We consider it is necessary to use the proper tables for right interpretation of received data for early diagnosis of glaucoma.

Machekhin, V.; Manaenkova, G.; Bondarenko, O.

2007-05-01

246

Is the rate of re-operation after primary lumbar microdiscectomy affected by surgeon grade or intra-operative lavage of the disc space?  

PubMed

STUDY DESIGN. Retrospective audit of consecutive patients. OBJECTIve. To investigate the re-operation rate following elective primary lumbar microdiscectomy and to determine whether principal surgeon grade and/or disc space lavage is a factor in recurrence. SUMMARY OF BACKGROUND DATA. Recurrent herniation of disc material following lumbar microdiscecomy surgery is one of the commonest complications of the procedure. Any reduction in the number of revision microdiscectomies performed per year would have a significant impact on patients' lives and on the health service economy. We undertook this study to ascertain whether principal surgeon grade and/or disc space lavage has an impact in reducing the re-operation rate. METHODS. We undertook a retrospective audit of patients who underwent elective primary lumbar microdiscectomy, over a 3-year period (n = 971). RESULTS. The overall re-operation rate for primary elective microdiscectomy was 3.8%, consistent with the published literature. The relative risk of re-operation in patients primarily operated by registrar surgeons was 1.2 fold the risk in patients operated by consultants (95% CI: 0.62, 2.35) although not statistically significant (p = 0.568). The risk of re-operation in the 'non lavage' group was 2.15 times the risk in the 'lavage' group (95% CI: 0.63, 7.34), but it did not reach significance (p = 0.222). CONCLUSIONS. Principal surgeon grade and intervertebral disc lavage have not been found conclusively to be factors in the rate of recurrence. This information is useful to reassure patients that their outcome from such surgery is not dependent on the grade of surgeon performing the operation. There is a possible trend towards intervertebral disc lavage reducing the rate of recurrence. PMID:23957779

Ellenbogen, Jonathan R; Marlow, William; Fischer, Benjamin E; Tsegaye, Magnum; Wilby, Martin J

2014-04-01

247

Enhancing cell migration in shape-memory alginate-collagen composite scaffolds: In vitro and ex vivo assessment for intervertebral disc repair.  

PubMed

Lower lumbar disc disorders pose a significant problem in an aging society with substantial socioeconomic consequences. Both inner tissue (nucleus pulposus) and outer tissue (annulus fibrosus) of the intervertebral disc are affected by such debilitating disorders and can lead to disc herniation and lower back pain. In this study, we developed an alginate-collagen composite porous scaffold with shape-memory properties to fill defects occurring in annulus fibrosus tissue of degenerated intervertebral discs, which has the potential to be administered using minimal invasive surgery. In the first part of this work, we assessed how collagen incorporation on preformed alginate scaffolds influences the physical properties of the final composite scaffold. We also evaluated the ability of annulus fibrosus cells to attach, migrate, and proliferate on the composite alginate-collagen scaffolds compared to control scaffolds (alginate only). In vitro experiments, performed in intervertebral disc-like microenvironmental conditions (low glucose and low oxygen concentrations), revealed that for alginate only scaffolds, annulus fibrosus cells agglomerated in clusters with limited infiltration and migration capacity. In comparison, for alginate-collagen scaffolds, annulus fibrosus cells readily attached and colonized constructs, while preserving their typical fibroblastic-like cell morphology with spreading behavior and intense cytoskeleton expression. In a second part of this study, we investigated the effects of alginate-collagen scaffold when seeded with bone marrow derived mesenchymal stem cells. In vitro, we observed that alginate-collagen porous scaffolds supported cell proliferation and extracellular matrix deposition (collagen type I), with secretion amplified by the local release of transforming growth factor-?3. In addition, when cultured in ex vivo organ defect model, alginate-collagen scaffolds maintained viability of transplanted mesenchymal stem cells for up to 5 weeks. Taken together, these findings illustrate the advantages of incorporating collagen as a means to enhance cell migration and proliferation in porous scaffolds which could be used to augment tissue repair strategies. PMID:25376622

Guillaume, Olivier; Naqvi, Syeda Masooma; Lennon, Kerri; Buckley, Conor Timothy

2014-11-01

248

Hydrodynamic instability in warped astrophysical discs  

E-print Network

Warped astrophysical discs are usually treated as laminar viscous flows, which have anomalous properties when the disc is nearly Keplerian and the viscosity is small: fast horizontal shearing motions and large torques are generated, which cause the warp to evolve rapidly, in some cases at a rate that is inversely proportional to the viscosity. However, these flows are often subject to a linear hydrodynamic instability, which may produce small-scale turbulence and modify the large-scale dynamics of the disc. We use a warped shearing sheet to compute the oscillatory laminar flows in a warped disc and to analyse their linear stability by the Floquet method. We find widespread hydrodynamic instability deriving from the parametric resonance of inertial waves. Even very small, unobservable warps in nearly Keplerian discs of low viscosity can be expected to generate hydrodynamic turbulence, or at least wave activity, by this mechanism.

Ogilvie, Gordon I

2013-01-01

249

Complications of Bryan cervical disc replacement.  

PubMed

The primary goals of cervical disc replacement are to avoid fusion in the affected segment, maintain the mobility and function of the involved cervical segments, allow patients to quickly return to routine activities and reduce or eliminate adjacent-segment disease. A large number of patients have already undergone, and more and more patients will in the future undergo, cervical disc replacement. The cervical device which best preserves movement, and has therefore been the device of choice, has been the Bryan cervical disc. Although a safe surgical technique has been demonstrated and favorable results of using the Bryan disc reported, some complications have also accompanied this arthroplasty. Complications of Bryan cervical disc replacement include those related to the operative approach and decompression process, loosening and failure of the device, postoperative kyphosis, heterotopic ossification, and loss of movement due to spontaneous fusion. In order to avoid these complications, strict patient selection criteria and a meticulous knowledge of anatomy are necessary. PMID:22009921

Cao, Jun-ming; Zhang, Ying-ze; Shen, Yong; Ding, Wen-yuan

2010-05-01

250

Evading death by vacuum  

NASA Astrophysics Data System (ADS)

In the Standard Model, the Higgs potential allows only one minimum at tree level. But the open possibility that there might be two scalar doublets enriches the vacuum structure, allowing for the risk that we might now be in a metastable state, which we dub the panic vacuum. Current experiments at the LHC are probing the Higgs particle predicted as a result of the spontaneous symmetry breaking. Remarkably, in the two Higgs model with a softly broken U(1) symmetry, the LHC experiments already allow to exclude many panic vacuum solutions.

Barroso, A.; Ferreira, P. M.; Ivanov, I. P.; Santos, Rui; Silva, João P.

2013-09-01

251

Evading death by vacuum  

E-print Network

In the Standard Model, the Higgs potential allows only one minimum at tree-level. But the open possibility that there might be two scalar doublets enriches the vacuum structure, allowing for the risk that we might now be in a metastable state, which we dub the panic vacuum. Current experiments at the LHC are probing the Higgs particle predicted as a result of the spontaneous symmetry breaking. Remarkably, in the two Higgs model with a softly broken U(1) symmetry, the LHC experiments already preclude panic vacuum solutions.

A. Barroso; P. M. Ferreira; I. P. Ivanov; Rui Santos; João P. Silva

2012-11-26

252

Outcomes of single-level cervical disc arthroplasty versus anterior cervical discectomy and fusion.  

PubMed

Several studies have established the short-term safety and efficacy of cervical disc arthroplasty (CDA) as compared to anterior cervical discectomy and fusion (ACDF). However, few single-center comparative trials have been performed, and current studies do not contain large numbers of patients. We retrospectively reviewed all patients from a single military tertiary medical center between August 2008 to August 2012 who underwent single-level CDA or single-level ACDF and compared their clinical outcomes and complications. A total of 259 consecutive patients were included in the study, 171 patients in the CDA group with an average follow-up of 9.8 (±9.9)months and 88 patients in the ACDF group with an average follow-up of 11.8 (±9.6)months. Relief of pre-operative symptoms was 90.1% in the CDA group and 86.4% in the ACDF group with rates of return to full pre-operative activity of 93.0% and 88.6%, respectively. Patients who underwent CDA had a higher rate of persistent posterior neck pain (15.8% versus 12.5%), and patients who underwent ACDF were at risk for symptomatic pseudarthrosis at a rate of 3.4%. Reoperation rates were higher in the ACDF group (5.7% versus 3.5%). To our knowledge, this review is the largest, non-funded, comparison study between single-level CDA and single-level ACDF. This study demonstrates that CDA is a safe and reliable alternative to ACDF in the treatment of cervical radiculopathy and myelopathy resulting from spondylosis and acute disc herniation. PMID:24986154

Tracey, Robert W; Kang, Daniel G; Cody, John P; Wagner, Scott C; Rosner, Michael K; Lehman, Ronald A

2014-11-01

253

Novel lap test determines the mechanics of delamination between annular lamellae of the intervertebral disc.  

PubMed

Delamination between lamellae of the annulus fibrosus is a crucial stage of intervertebral disc herniation, and to better understand the mechanics of the delamination process, a novel lap test was devised. Specimens consisting of two adjacent, naturally bonded lamellae were obtained from the cervical region of frozen porcine spines. They were cut into specimens nominally 3.5mm wide by 7 mm long and tabs of the deep and superficial layers were removed from opposite ends of the specimens so that a 4.5-5.0mm long intact interface remained between the lamellae. Specimens were mounted in a BioTester tensile instrument using BioRake attachments having 5 sharpened points side-by-side, and they were strained at 2%/s. Force-time curves were obtained and, using tracking software, a detailed map was made of the time course of the displacements within the specimens. Extensibility of the lamellae themselves was found to substantially complicate interpretation of the data. The experiments, together with mathematical analyses and finite element models, show that much of the shear load is transferred between lamellae at the ends of the bonded region, a finding of clinical importance. The inter-lamellae bond was found to have a peak strength of 0.30 ± 0.05 N/mm of specimen width (not to be confused with lap length), and the remarkable ability to carry substantial load even when lamellae had displaced up to 10mm relative to each other. PMID:20850752

Gregory, Diane E; Veldhuis, Jim H; Horst, Caleb; Wayne Brodland, G; Callaghan, Jack P

2011-01-01

254

Vacuum Camera Cooler  

NASA Technical Reports Server (NTRS)

Acquiring cheap, moving video was impossible in a vacuum environment, due to camera overheating. This overheating is brought on by the lack of cooling media in vacuum. A water-jacketed camera cooler enclosure machined and assembled from copper plate and tube has been developed. The camera cooler (see figure) is cup-shaped and cooled by circulating water or nitrogen gas through copper tubing. The camera, a store-bought "spy type," is not designed to work in a vacuum. With some modifications the unit can be thermally connected when mounted in the cup portion of the camera cooler. The thermal conductivity is provided by copper tape between parts of the camera and the cooled enclosure. During initial testing of the demonstration unit, the camera cooler kept the CPU (central processing unit) of this video camera at operating temperature. This development allowed video recording of an in-progress test, within a vacuum environment.

Laugen, Geoffrey A.

2011-01-01

255

Pumpdown and Vacuum Pumps  

NSDL National Science Digital Library

This is a link to a PDF version of lecture slides that discuss vacuum pumpdown. Graphics are included which depict pumpdown procedure, venting procedure, pressure curves and system pumpdown. Keywords: Outgassing, pressure range, rotary vane, rotary piston, roots blower

Rack, Philip D.

256

Osseous erosion by herniated nucleus pulposus mimicking intraspinal tumor: a case report  

PubMed Central

Erosion of spinal osseous structure, so-called scalloping, has been rarely reported associated with herniated nucleus pulposus (HNP). We report a rare case of HNP causing erosion of the spinal osseous structure (including lamina). The patient was an 81-year-old woman with 3-year history of low-back pain and left leg radiating pain. Muscle weakness of the left leg was also apparent. Computed tomography following myelography showed severe compression of the dural sac at the level of L3–L4; furthermore, erosion of the lamina, pedicle, and vertebral body was noted, indicating that the space-occupying mass was most probably a tumorous lesion. The mass also showed calcification inside. During the surgery, the mass was confirmed to be an HNP with calcification. Following resection, the pain disappeared. Surgeons should be aware of the possibility of scalloping of the vertebrae caused by HNP mimicking a tumorous lesion. PMID:21103903

Yoshioka, Shinji; Sakai, Toshinori; Tamura, Tatsuya; Kosaka, Hirofumi; Yasui, Natsuo

2010-01-01

257

Spondylocostal dysostosis with tetralogy of Fallot and herniation of the spleen through the diaphragm.  

PubMed

Spondylocostal dysostosis (SCD) is a very rare syndrome characterized by vertebral malformation and rib deformity. Some of the patients with SCD have other birth defects in the central nervous system, the genitourinary tract, diaphragm or heart and so forth. There have been reported SCD with complex congenital heart disease, such as pulmonary atresia, double outlet right ventricle, and d-transposition of great arteries. However, there have been no reported SCD patients with confirmed tetralogy of Fallot (TOF). Here, a patient with SCD having a very rare combination of rib defects on the right side and left-sided scoliosis, tetralogy of Fallot, and diaphragmatic spleen herniation, which had not been reported before, was described. PMID:24666313

Nagasawa, Hiroyuki; Koyama, Toshinari; Sasai, Hideo; Kohno, Yoshinori; Yamamoto, Yutaka; Kondo, Masashi; Sugawara, Masami; Terazawa, Daisuke; Miura, Ryosuke

2014-08-01

258

Autologous adipose stem cells and polylactide discs in the replacement of the rabbit temporomandibular joint disc.  

PubMed

The temporomandibular joint (TMJ) disc lacks functional replacement after discectomy. We investigated tissue-engineered bilayer polylactide (PLA) discs and autologous adipose stem cells (ASCs) as a potential replacement for the TMJ disc. These ASC discs were pre-cultured either in control or in differentiation medium, including transforming growth factor (TGF)-?1 for one week. Prior to implantation, expression of fibrocartilaginous genes was measured by qRT-PCR. The control and differentiated ASC discs were implanted, respectively, in the right and left TMJs of rabbits for six (n = 5) and 12 months (n = 5). Thereafter, the excised TMJ areas were examined with cone beam computed tomography (CBCT) and histology. No signs of infection, inflammation or foreign body reactions were detected at histology, whereas chronic arthrosis and considerable condylar hypertrophy were observed in all operated joints at CBCT. The left condyle treated with the differentiated ASC discs appeared consistently smoother and more sclerotic than the right condyle. The ASC disc replacement resulted in dislocation and morphological changes in the rabbit TMJ. The ASC discs pre-treated with TGF-?1 enhanced the condylar integrity. While adverse tissue reactions were not shown, the authors suggest that with improved attachment and design, the PLA disc and biomaterial itself would hold potential for TMJ disc replacement. PMID:23720535

Ahtiainen, Katja; Mauno, Jari; Ellä, Ville; Hagström, Jaana; Lindqvist, Christian; Miettinen, Susanna; Ylikomi, Timo; Kellomäki, Minna; Seppänen, Riitta

2013-08-01

259

Herniated Disk  

MedlinePLUS

... Yes, exercises can be helpful. Begin by stretching. Bend over forward and bend to the sides. Start these exercises after your ... back by reducing the pressure on your disk Bend your knees and hips when you lift something, ...

260

Herniated disk  

MedlinePLUS

... diet and exercise are very important for improving back pain. Physical therapy is important for nearly everyone with ... with treatment. But you may have long-term back pain even after treatment. It may take several months ...

261

Nutrient supply and intervertebral disc metabolism.  

PubMed

The metabolic environment of disc cells is governed by the avascular nature of the tissue. Because cellular energy metabolism occurs mainly through glycolysis, the disc cells require glucose for survival and produce lactic acid at high rates. Oxygen is also necessary for cellular activity, although not for survival; its pathway of utilization is unclear. Because the tissues are avascular, disc cells depend on the blood supply at the margins of the discs for their nutrients. The nucleus and inner anulus of the disc are supplied by capillaries that arise in the vertebral bodies, penetrate the subchondral bone, and terminate at the bone-disc junction. Small molecules such as glucose and oxygen then reach the cells by diffusion under gradients established by the balance between the rate of transport through the tissue to the cells and the rate of cellular demand. Metabolites such as lactic acid are removed by the reverse pathway. The concentrations of nutrients farthest from the source of supply can thus be low; oxygen concentrations as low as 1% have been measured in the discs of healthy animals. Although gradients cannot be measured easily in humans, they can be calculated. Measured concentrations in surgical patients are in agreement with calculated values. PMID:16595440

Grunhagen, Thijs; Wilde, Geoffrey; Soukane, Dahbia Mokhbi; Shirazi-Adl, Saeed A; Urban, Jill P G

2006-04-01

262

DISC1 genetics, biology and psychiatric illness  

PubMed Central

Psychiatric disorders are highly heritable, and in many individuals likely arise from the combined effects of genes and the environment. A substantial body of evidence points towards DISC1 being one of the genes that influence risk of schizophrenia, bipolar disorder and depression, and functional studies of DISC1 consequently have the potential to reveal much about the pathways that lead to major mental illness. Here, we review the evidence that DISC1 influences disease risk through effects upon multiple critical pathways in the developing and adult brain. PMID:23550053

THOMSON, Pippa A.; MALAVASI, Elise L.V.; GRÜNEWALD, Ellen; SOARES, Dinesh C.; BORKOWSKA, Malgorzata; MILLAR, J. Kirsty

2012-01-01

263

Optical disc system for baseband HDTV signal  

NASA Astrophysics Data System (ADS)

We developed a new type of optical disc system for baseband high definition television (signal. In conventional technology we cannot record HDTV signal for sufficiently long time because it has very wide bandwidth. In this system we can solve this problem based on the following technology HDTV signal is divided into two channels recorded on the both sides of a 30 cm diameter disc and reproduced with two optical pickups at the same time. As a result this system can continuously play HDTV signal for more than 30 minutes with constant-linear-velocity (CLV) disc. 1 .

Matsushita, Katsuhiko; Ohnaka, Takashi; Hosohara, Nabuhiro; Idegata, Osamu; Tanaka, Tatsuo

1992-08-01

264

ISABELLE vacuum systems  

SciTech Connect

The Intersecting Storage Accelerator (ISABELLE) consists of two rings having a circumference of 3.8 km each. In these rings superconducting magnets, held at 4 K, bend and focus the proton beam which is accelerated up to 400 GeV. Due to very different pressure requirements, ISABELLE has two completely independent vacuum systems. One, which operates at 1 x 10/sup -11/ Torr, provides a very clean environment for the circulating proton beam. Here only ion and titanium sublimation pumps are used to provide the vacuum. The other system maintains superconducting magnet vessels at a pressure below 1 x 10/sup -4/ Torr, since at this pressure the gas conduction becomes negligible. In this so-called insulating vacuum system, turbomolecular pumps pump the inadvertent small helium leaks. Other gases are cryocondensed on the cold surfaces of the cryogenic system. The basic element of ISABELLE known as Full Cell containing 45 meters of beam tube, 8 pumping stations, 8 superconducting magnets and complete instrumentation has been constructed, leak checked and tested. All design parameters have been achieved in both vacuum systems. The two vacuum systems are described with particular emphasis on the influence of superconducting magnets in the selection of materials and UHV components.

Halama, H J

1980-01-01

265

Only marginal alignment of disc galaxies  

E-print Network

Testing theories of angular-momentum acquisition of rotationally supported disc galaxies is the key to understand the formation of this type of galaxies. The tidal-torque theory tries to explain this acquisition process in a cosmological framework and predicts positive autocorrelations of angular-momentum orientation and spiral-arm handedness on distances of 1Mpc/h. This disc alignment can also cause systematic effects in weak-lensing measurements. Previous observations claimed discovering such correlations but did not account for errors in redshift, ellipticity and morphological classifications. We explain how to rigorously propagate all important errors. Analysing disc galaxies in the SDSS database, we find that positive autocorrelations of spiral-arm handedness and angular-momentum orientations on distances of 1Mpc/h are plausible but not statistically significant. This result agrees with a simple hypothesis test in the Local Group, where we find no evidence for disc alignment. Moreover, we demonstrate tha...

Andrae, Rene

2011-01-01

266

Stellar Wind Erosion of Protoplanetary Discs  

E-print Network

An analytic model is developed for the erosion of protoplanetary gas discs by high velocity magnetized stellar winds. The winds are centrifugally driven from the surface of rapidly rotating, strongly magnetized young stars. The presence of the magnetic field in the wind leads to Reynolds numbers sufficiently large to cause a strongly turbulent wind/disk boundary layer which entrains and carries away the disc gas. The model uses the conservation of mass and momentum in the turbulent boundary layer. The time-scale for significant erosion depends on the disc accretion speed, accretion rate and on the wind mass loss rate. The time-scale is estimated to be ~2E6 yr. The stellar wind erosion may act in conjunction with photo-evaporation of the discs.

Schnepf, Neesha R; Romanova, Marina

2014-01-01

267

Kinematic structures in galactic disc simulations  

NASA Astrophysics Data System (ADS)

N-body and test particle simulations have been used to characterize the stellar streams in the galactic discs of Milky Way type galaxies. Tools such as the second and third order moments of the velocity ellipsoid and clustering methods -EM-WEKA and FoF- allow characterizing these kinematic structures and linking them to the stellar overdensities and to the resonant regions all through the disc.

Roca-Fàbrega, S.; Romero-Gómez, M.; Figueras, F.; Antoja, T.; Valenzuela, O.

2011-10-01

268

Investigation of cryogenic rupture disc design  

NASA Technical Reports Server (NTRS)

Rupture disc designs of both the active (command actuated) and passive (pressure ruptured) types were evaluated for performance characteristics at cryogenic temperatures and for capability to operate in a variety of cryogens, including gaseous and liquid fluorine. The test results, coupled with information from literature and industry searches, were used to establish a statement of design criteria and recommended practices for application of rupture discs to cryogenic rocket propellant feed and vent systems.

Keough, J. B.; Oldland, A. H.

1973-01-01

269

Particle Acceleration in (by) Accretion Discs  

E-print Network

I present a model for acceleration of protons by the second-order Fermi process acting on randomly scrambled magnetic flux arches above an accretion disc. The accelerated protons collide with thermal protons in the disc, producing degraded energetic protons, charged and neutral pions, and neutrons. The pions produce gamma-rays by spontaneous decay of $\\pi^0$ and by bremsstrahlung and Compton processes following the decay of $\\pi^\\pm$ to $e^\\pm$.

J. I. Katz

1992-05-04

270

Disc valve for sampling erosive process streams  

DOEpatents

A four-port disc valve for sampling erosive, high temperature process streams. A rotatable disc defining opposed first and second sampling cavities rotates between fired faceplates defining flow passageways positioned to be alternatively in axial alignment with the first and second cavities. Silicon carbide inserts and liners composed of .alpha. silicon carbide are provided in the faceplates and in the sampling cavities to limit erosion while providing lubricity for a smooth and precise operation when used under harsh process conditions.

Mrochek, John E. (Oak Ridge, TN); Dinsmore, Stanley R. (Norris, TN); Chandler, Edward W. (Knoxville, TN)

1986-01-01

271

Long-term clinical outcomes and radiological findings and their correlation with each other after standard open discectomy for lumbar disc herniation.  

PubMed

OBJECT This retrospective study was designed to evaluate the clinical outcomes and radiological findings after open lumbar discectomy (OLD) in patients who were followed up for 10 years or longer. METHODS The authors classified 79 patients who had a mean age (± SD) of 53.6 ± 13.6 years (range 30-78 years) into 4 groups according to the length of their follow-up. Patients in Group 1 were followed up for 10-14 years, in Group 2 for 15-19 years, in Group 3 for 20-24 years, and in Group 4 for more than 25 years. In all of these patients, the clinical outcomes were assessed by using patients' self-reported scores on visual analog scales (VASs) measuring back and leg pain and by using scores from the Oswestry Disability Index (ODI). In addition, 10 radiological parameters suggesting degenerative changes or instability at the operated segment were recorded at various time points and used to calculate a numeric radiological finding (NRF) score by rating a presence for each finding of spinal degeneration or instability as 1. RESULTS The authors observed that OLD decreased pain and disability scores in all groups. Numeric radiological findings were highest in Group 4, and a significant correlation was detected between NRFs and VAS scores of back pain (p = 0.039). In this cohort, the reoperation rate was 13.9% during a mean follow-up period of 15.3 years. Clinical outcomes tended to be most favorable in Group 1, representing patients who had OLD most recently, and they tended to deteriorate in the other 3 groups, indicating some worsening of outcomes over time. Degeneration of the spine at the operated level measured with radiographic methods tended to increase over time, but some stabilization was observed. Although spinal degeneration was stable, clinical outcomes deteriorated over time. CONCLUSIONS This cross-sectional assessment of a retrospective cohort indicates that outcomes after OLD deteriorate over time. Increased back pain indicated a worsening of clinical outcomes, and this worsening was correlated with radiological findings of degeneration at the operated segment. PMID:25431963

Son, Il-Nam; Kim, Young-Hoon; Ha, Kee-Yong

2015-02-01

272

Prolonged conservative treatment or 'early' surgery in sciatica caused by a lumbar disc herniation: rationale and design of a randomized trial [ISRCT 26872154  

Microsoft Academic Search

BACKGROUND: The design of a randomized multicenter trial is presented on the effectiveness of a prolonged conservative treatment strategy compared with surgery in patients with persisting intense sciatica (lumbosacral radicular syndrome). METHODS\\/DESIGN: Patients presenting themselves to their general practitioner with disabling sciatica lasting less than twelve weeks are referred to the neurology outpatient department of one of the participating hospitals.

Wilco C Peul; Hans C van Houwelingen; Wilbert B van der Hout; Ronald Brand; Just AH Eekhof; Joseph ThJ Tans; Ralph TWM Thomeer; Bart W Koes

2005-01-01

273

Fibrin in intervertebral disc tissue engineering.  

PubMed

Fibrin is clinically employed as a versatile, safe, and clinically applicable sealant and cell carrier. It has been able to support disc cell survival, favor extracellular matrix production, and enhance the efficiency of cell transfer in the intervertebral disc (IVD). The aim of this review was to evaluate how fibrin has been used in vitro, in vivo, and in clinical trials for IVD tissue engineering. Within the in vitro studies, disc cells were cultured in fibrin alone or combined with other materials and a difference in the behavior of nucleus pulposus (NP) and annulus fibrosus (AF) cells was sometimes reported, but in general, the formation of fibrocartilaginous matrix was observed. Moreover, data concerning the fibrin long-term stability and its anti-inflammatory properties were found. Disc cells of human origin were never employed in combination with fibrin in vivo or in clinical trials. In vivo, disc degeneration models used to test the fibrin properties essentially involved NP injuries. The addition of cells, in particular if terminally differentiated, to the injected fibrin seemed to promote a more physiological matrix in comparison with fibrin alone. Important aspects should be further investigated in future studies such as the use of fibrin to treat AF lesions as well as the mechanical properties of the fibrin-based biomaterials and of the neoformed tissue. Finally, in vivo studies and clinical trials with in situ injection of fibrin and human disc cells should be performed. PMID:24961887

Colombini, Alessandra; Ceriani, Cristina; Banfi, Giuseppe; Brayda-Bruno, Marco; Moretti, Matteo

2014-12-01

274

Vacuum driven accelerated expansion  

E-print Network

It has been shown that an improved estimation of quantum vacuum energy can yield not only acceptable but also experimentally sensible results. The very idea consists in a straightforward extraction of gravitationally interacting part of the full quantum vacuum energy by means of gauge transformations. The implementation of the idea has been performed in the formalism of effective action, in the language of Schwinger's proper time and the Seeley-DeWitt heat kernel expansion, in the background of the Friedmann-Robertson-Walker geometry.

Bogus?aw Broda; Piotr Bronowski; Marcin Ostrowski; Micha? Szanecki

2008-12-29

275

The Disc-Jet Connection  

E-print Network

A large body of theoretical and computational work shows that jets - modelled as magnetized disk winds - exert an external torque on their underlying disks that can efficiently remove angular momentum and act as major drivers of disk accretion. These predictions have recently been confirmed in direct HST measurements of the jet rotation and angular momentum transport in low mass protostellar systems. We review the theory of disc winds and show that their physics is universal and scales to jets from both low and high mass star forming regions. This explains the observed properties of outflows in massive star forming regions, before the central massive star generates an ultracompact HII region. We also discuss the recent numerical studies on the formation of massive accretion disks and outflows through gravitational collapse, including our own work on 3D Adaptive Mesh simulations (using the FLASH code) of the hydromagnetic collapse of an initial rotating, and cooling Bonner-Ebert sphere. Magnetized collapse gives rise to outflows. Our own simulations show that both a jet-like disk wind on sub AU scales, and a larger scale molecular outflow occur (Banerjee and Pudritz 2005).

Ralph E. Pudritz; Robi Banerjee

2005-07-11

276

A vacuum chamber feedthrough  

NASA Technical Reports Server (NTRS)

Simple and inexpensive microwave feedthrough has been designed which transfers 130 ns, 5kV pulse into vacuum chamber. Feedthrough may be used over wide range and is adaptable to most coaxial cables, since either multistrand or single strand center conductor cable can be used.

Brown, V. D.

1973-01-01

277

Vacuum ultraviolet holography  

NASA Technical Reports Server (NTRS)

The authors report the first demonstration of holographic techniques in the vacuum ultraviolet spectral region. Holograms were produced with coherent 1182 A radiation. The holograms were recorded in polymethyl methacrylate and read out with an electron microscope. A holographic grating with a fringe spacing of 836 A was produced and far-field Fraunhofer holograms of sub-micron particles were recorded.

Bjorklund, G. C.; Harris, S. E.; Young, J. F.

1974-01-01

278

Vacuum ultraviolet holography  

NASA Technical Reports Server (NTRS)

We report the first demonstration of holographic techniques in the vacuum ultraviolet spectral region. Holograms were produced with coherent 1182-A radiation. The holograms were recorded in polymethyl methacrylate and examined with an electron microscope. A holographic grating with a fringe spacing of 386 A was produced and far-field Fraunhofer holograms of submicron particles were recorded.

Bjorklund, G. C.; Harris, S. E.; Young, J. F.

1974-01-01

279

Vacuum insulator coating development  

Microsoft Academic Search

The authors discuss the electrical and mechanical requirements for vacuum insulators in high peak power generators. To increase the lifetime of these insulators, they have developed a coating called Dendresist. This coating has extended the insulator lifetime on the PITHON, DM2, CASINO, and Double-EAGLE pulsed power generators. They describe its development, and compare its electrical and mechanical strength to that

I. S. Roth; P. S. Sincerny; L. Mandelcorn; M. Mendelsohn; D. Smith; T. G. Engel; L. Schlitt; C. M. Cooke

1997-01-01

280

On Lovelock vacuum solution  

E-print Network

We show that the asymptotic large $r$ limit of all Lovelock vacuum and electrovac solutions with $\\Lambda$ is always the Einstein solution in $d \\geq 2n+1$ dimensions. It is completely free of the order $n$ of the Lovelock polynomial indicating universal asymptotic behaviour.

Naresh Dadhich

2010-12-18

281

Transcalvarial brain herniation volume after decompressive craniectomy is the difference between two spherical caps.  

PubMed

Decompressive craniectomy (DC) is a surgical procedure used to relieve severely increased intracranial pressure (ICP) by removing a portion of the skull. Following DC, the brain expands through the skull defect created by DC, resulting in transcalvarial herniation (TCH). Traditionally, people measure only changes in the ICP but not in the intracranial volume (ICV), which is equivalent to the volume of TCH (VTCH), in patients undergoing DC. We constructed a simple model of the cerebral hemispheres, assuming the shape of the upper half of a sphere with a radius of 8cm. We hypothesized that the herniated brain following DC also conforms to the shape of a spherical cap. Considering that a circular piece of the skull with a radius of a was removed, VTCH is the volume difference between 2 spherical caps at the operated side and the corresponding non-operated side, which represents the pre-DC volume underneath the removed skull due to the bilateral symmetry of the skull and the brain. Subsequently, we hypothesized that the maximal extent of TCH depends on a because of the biomechanical limitations imposed by the inelastic scalp. The maximum value of VTCH is 365.0mL when a is 7.05cm and the height difference between the spherical caps (?h) at its maximum is 2.83cm. To facilitate rapid calculation of VTCH, we proposed a simplified estimation formula, VˆTCH=12A(2)?h, where A=2a. With the a value ranging between 0 and 7cm, the ratio between VˆTCH and VTCH ranges between 0.77 and 1.27, with different ?h values. For elliptical skull defects with base diameters of A and C, the formula changes to VˆTCH=12AC?h. If our hypothesis is correct, surgeons can accurately calculate VTCH after DC. Furthermore, this can facilitate volumetric comparisons between the effects of DCs in skulls of varying sizes, allowing quantitative comparisons between ICVs in addition to ICPs. PMID:25583637

Liao, Chun-Chih; Tsai, Yi-Hsin; Chen, Yi-Long; Huang, Ke-Chun; Chiang, I-Jen; Wong, Jau-Min; Xiao, Furen

2015-03-01

282

Numerical simulations of protostellar encounters III. Non-coplanar disc-disc encounters  

E-print Network

It is expected that an average protostar will undergo at least one impulsive interaction with a neighbouring protostar whilst a large fraction of its mass is still in a massive, extended disc. If protostars are formed individually within a cluster before falling together and interacting, there should be no preferred orientation for such interactions. As star formation within clusters is believed to be coeval, it is probable that during interactions, both protostars possess massive, extended discs. We have used an SPH code to carry out a series of simulations of non-colpanar disc-disc interactions. We find that non-coplanar interactions trigger gravitational instabilities in the discs, which may then fragment to form new companions to the existing stars. (This is different from coplanar interactions, in which most of the new companion stars form after material in the discs has been swept up into a shock layer, and this then fragments.) The original stars may also capture each other, leading to the formation of a small-N cluster. If every star undergoes a randomly oriented disc-disc interaction, then the outcome will be the birth of many new stars. Approximately two-thirds of the stars will end up in multiple systems.

S. J. Watkins; A. S. Bhattal; H. M. J. Boffin; N. Francis; A. P. Whitworth

1998-05-28

283

Isolation and Characterization of Adult Spinal Disc Stem Cells from Healthy Human Spinal Disc Tissues  

PubMed Central

This report details the isolation, culture, and characterization of spinal disc stem cells derived from human adult spinal disc tissue specimens. Using stem cell suspension culture methods and biology, human adult spinal disc stem cells were isolated and monoclonally cultured into multicellular sphere-like clusters (discospheres). Discospheres from the first culture series were collected, processed, and replated as single stem cells for serial expansion studies using suspension culture, demonstrating linear expansion was possible. Discospheres and adult spinal disc stem cells were plated on matrix coated culture surfaces in stem cell media for several hours to allow fixation, and assayed for the stem cell biomarkers. Discospheres and adult spinal disc stem cells were plated on laminin-coated culture surfaces in chondrogenic media and culture conditions for 14 days to differentiate them into NP cells. NP cells cultured from these experiments demonstrated NP morphology and phenotype; NP biomarker expression, secretion of extracellular matrix, and the ability to be serially passaged with large volume expansion possible. Tissue engineering studies using the “burst kinetic assay”, demonstrated that discospheres have remarkable intrinsic developmental and tissue engineering biology that is robust and organized. In summary, adult disc stem cells and NP cells have been isolated, cultured, and characterized, from healthy spinal disc tissues. These findings demonstrate the important potential to be explored for using stem cell based tissue engineering for the treatment of degenerative disc disease (DDD).

Duntsch, Christopher; Dillard, Erika; Akbar, Umar

2015-01-01

284

Liquid immersion deep-UV optical disc mastering for high data capacity ROM discs  

NASA Astrophysics Data System (ADS)

In this paper we describe the liquid immersion mastering technique and its application to the mastering of ROM discs for the Blu-ray Disc system and for ROM discs with considerably higher data densities. Replicated 25GB BD-ROM discs were evaluated using a standard blue test player (?=405nm, NA=0.85). A bottom jitter value with limit equalizer of less than 5% was measured. Also the values of asymmetry, normalized push pull and symbol error rate were well within the Blu-ray Disc format specification, offering a large process window. Full-format BD-ROM test discs with high definition video content were mastered and their successful read-back was demonstrated. In addition we show that liquid immersion mastering can successfully be applied for mastering of considerably higher densities. Measurements on replicated discs up to data densities above 40GB per layer are discussed. The present results demonstrate that liquid immersion mastering is a proven technology for the mass-production of high data capacity ROM discs.

Neijzen, Jaap H. M.; Meinders, Erwin R.; Boamfa, Marius I.; Chen, Dianyong

2005-09-01

285

Modeling and optimization of an elastic arthroplastic disc for a degenerated disc  

NASA Astrophysics Data System (ADS)

A three-dimensional finite element model (FEM) of the L3-L4 motion segment using ABAQUS v 6.9 has been developed. The model took into account the material nonlinearities and is imposed different loading conditions. In this study, we validated the model by comparison of its predictions with several sets of experimental data. Disc deformation under compression and segmental rotational motions under moment loads for the normal disc model agreed well with the corresponding in vivo studies. By linking ABAQUS with MATLAB 2010.a, we determined the optimal Young s modulus as well as the Poisson's ratio for the artificial disc under different physiologic loading conditions. The results of the present study confirmed that a well-designed elastic arthroplastic disc preferably has an annulus modulus of 19.1 MPa and 1.24 MPa for nucleus section and Poisson ratio of 0.41 and 0.47 respectively. Elastic artificial disc with such properties can then achieve the goal of restoring the disc height and mechanical function of intact disc under different loading conditions and so can reduce low back pain which is mostly caused due to disc degeneration.

Ghouchani, Azadeh; Ravari, Mohammad; Mahmoudi, Farid

2011-10-01

286

Angular Momentum Transfer in Star-Discs Encounters: The Case of Low-Mass Discs  

E-print Network

A prerequisite for the formation of stars and planetary systems is that angular momentum is transported in some way from the inner regions of the accretion disc. Tidal effects may play an important part in this angular momentum transport. Here the angular momentum transfer in an star-disc encounter is investigated numerically for a variety of encounter parameters in the case of low mass discs. Although good agreement is found with analytical results for the entire disc, the loss {\\it inside} the disc can be up to an order of magnitude higher than previously assumed. The differences in angular momentum transport by secondaries on a hyperbolic, parabolic and elliptical path are shown, and it is found that a succession of distant encounters might be equally, if not more, successful in removing angular momentum than single close encounter.

S. Pfalzner

2003-10-27

287

A radiation hard vacuum switch  

DOEpatents

A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction. 3 figs.

Boettcher, G.E.

1988-07-19

288

Stochastic oscillations of general relativistic discs  

NASA Astrophysics Data System (ADS)

We analyse the general relativistic oscillations of thin accretion discs around compact astrophysical objects interacting with the surrounding medium through non-gravitational forces. The interaction with the external medium (a thermal bath) is modelled via a friction force and a random force, respectively. The general equations describing the stochastically perturbed discs are derived by considering the perturbations of trajectories of the test particles in equatorial orbits, assumed to move along the geodesic lines. By taking into account the presence of a viscous dissipation and of a stochastic force, we show that the dynamics of the stochastically perturbed discs can be formulated in terms of a general relativistic Langevin equation. The stochastic energy transport equation is also obtained. The vertical oscillations of the discs in the Schwarzschild and Kerr geometries are considered in detail, and they are analysed by numerically integrating the corresponding Langevin equations. The vertical displacements, velocities and luminosities of the stochastically perturbed discs are explicitly obtained for both the Schwarzschild and the Kerr cases.

Harko, Tiberiu; Mocanu, Gabriela Raluca

2012-04-01

289

Design concepts in lumbar total disc arthroplasty  

PubMed Central

The implantation of lumbar disc prostheses based on different design concepts is widely accepted. This paper reviews currently available literature studies on the biomechanics of TDA in the lumbar spine, and is targeted at the evaluation of possible relationships between the aims of TDA and the geometrical, mechanical and material properties of the various available disc prostheses. Both theoretical and experimental studies were analyzed, by a PUBMED search (performed in February 2007, revised in January 2008), focusing on single level TDA. Both semi-constrained and unconstrained lumbar discs seem to be able to restore nearly physiological IAR locations and ROM values. However, both increased and decreased ROM was stated in some papers, unrelated to the clinical outcome. Segmental lordosis alterations after TDA were reported in most cases, for both constrained and unconstrained disc prostheses. An increase in the load through the facet joints was documented, for both semi-constrained and unconstrained artificial discs, but with some contrasting results. Semi-constrained devices may be able to share a greater part of the load, thus protecting the surrounding biological structure from overloading and possible early degeneration, but may be more susceptible to wear. The next level of development will be the biomechanical integration of compression across the motion segment. All these findings need to be supported by long-term clinical outcome studies. PMID:18946684

Bellini, Chiara M.; Zweig, Thomas; Ferguson, Stephen; Raimondi, Manuela T.; Lamartina, Claudio; Brayda-Bruno, Marco; Fornari, Maurizio

2008-01-01

290

Surge-damping vacuum valve  

DOEpatents

A valve having a mechanism for damping out flow surges in a vacuum system which utilizes a slotted spring-loaded disk positioned adjacent the valve's vacuum port. Under flow surge conditions, the differential pressure forces the disk into sealing engagement with the vacuum port, thereby restricting the flow path to the slots in the disk damping out the flow surge.

Bullock, Jack C. (Pleasanton, CA); Kelly, Benjamin E. (Tracy, CA)

1980-01-01

291

Portable vacuum object handling device  

SciTech Connect

The disclosure relates to a portable device adapted to handle objects which are not to be touched by hand. A piston and bore wall form a vacuum chamber communicating with an adaptor sealably engageable with an object to be lifted. The piston is manually moved and set to establish vacuum. A valve is manually actuable to apply the vacuum to lift the object.

Anderson, G.H.

1981-07-30

292

Portable vacuum object handling device  

DOEpatents

The disclosure relates to a portable device adapted to handle objects which are not to be touched by hand. A piston and bore wall form a vacuum chamber communicating with an adaptor sealably engageable with an object to be lifted. The piston is manually moved and set to establish vacuum. A valve is manually actuatable to apply the vacuum to lift the object.

Anderson, Gordon H. (Los Alamos, NM)

1983-08-09

293

Influence of the temperature on the tribological behaviour of PEEK composites in vacuum environment  

NASA Astrophysics Data System (ADS)

This paper describes tribological experiments carried out with polyetheretherketone (PEEK), filled with carbon fibres and solid lubricants (polytetrafluoroethylene (PTFE), graphite or MoS2), against steel discs. Oscillating sliding tests were performed in high vacuum environment in the temperature range between -40°C and +160°C. Results indicate that MoS2 filled PEEK show the best tribological performance in vacuum. Particularly, in the lower temperature range and at higher loads the friction behaviour is improved by the MoS2 content.

Theiler, G.; Gradt, T.

2008-03-01

294

Compact vacuum insulation  

DOEpatents

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially "point" or "line" contacts with the metal wall sheets. In the case of monolithic spacers that form "line" contacts, two such spacers with the line contacts running perpendicular to each other form effectively "point" contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

Benson, David K. (Golden, CO); Potter, Thomas F. (Denver, CO)

1993-01-01

295

Compact vacuum insulation embodiments  

DOEpatents

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially "point" or "line" contacts with the metal wall sheets. In the case of monolithic spacers that form "line" contacts, two such spacers with the line contacts running perpendicular to each other form effectively "point" contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

Benson, David K. (Golden, CO); Potter, Thomas F. (Denver, CO)

1992-01-01

296

Compact vacuum insulation  

DOEpatents

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point'' or line'' contacts with the metal wall sheets. In the case of monolithic spacers that form line'' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point'' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

Benson, D.K.; Potter, T.F.

1993-01-05

297

Integrated structure vacuum tube  

NASA Technical Reports Server (NTRS)

High efficiency, multi-dimensional thin film vacuum tubes suitable for use in high temperature, high radiation environments are described. The tubes are fabricated by placing thin film electrode members in selected arrays on facing interior wall surfaces of an alumina substrate envelope. Cathode members are formed using thin films of triple carbonate. The photoresist used in photolithography aids in activation of the cathodes by carbonizing and reacting with the reduced carbonates when heated in vacuum during forming. The finely powdered triple carbonate is mixed with the photoresist used to delineate the cathode locations in the conventional solid state photolithographic manner. Anode and grid members are formed using thin films of refractory metal. Electron flow in the tubes is between grid elements from cathode to anode as in a conventional three-dimensional tube.

Dimeff, J.; Kerwin, W. J. (inventors)

1976-01-01

298

Vacuum tool manipulator  

DOEpatents

Apparatus for manipulating a vacuum hose in a reactor vessel comprises a housing with two opposing openings, an arm carried by the housing and deployable from a stowed position essentially completely within the housing to an extended position where the arm extends through the two openings in a generally horizontal position. The arm preferably has a two-fingered gripping device for gripping the vacuum hose but may carry a different end effector such as a grinding wheel. The fingers are opened and closed by one air cylinder. A second air cylinder extends the device. A third air cylinder within the housing pivotally pulls the opposing end of the arm into the housing via a pivoting member pivotally connected between the third air cylinder shaft and the arm.

Zollinger, William T. (3927 Almon Dr., Martinez, GA 30907)

1993-01-01

299

Vacuum tool manipulator  

DOEpatents

Apparatus for manipulating a vacuum hose in a reactor vessel comprises a housing with two opposing openings, an arm carried by the housing and deployable from a stowed position essentially completely within the housing to an extended position where the arm extends through the two openings in a generally horizontal position. The arm preferably has a two-fingered gripping device for gripping the vacuum hose but may carry a different end effector such as a grinding wheel. The fingers are opened and closed by one air cylinder. A second air cylinder extends the device. A third air cylinder within the housing pivotally pulls the opposing end of the arm into the housing via a pivoting member pivotally connected between the third air cylinder shaft and the arm. 6 figures.

Zollinger, W.T.

1993-11-23

300

The vacuum energy crisis  

E-print Network

The smallness of the vacuum energy density and its near coincidence with the average matter density of the universe are naturally explained by anthropic selection. An alternative explanation, based on the cyclic model of Steinhardt and Turok, does not address the coincidence problem and is therefore less convincing. This article appeared in ``Science'' (4 May 2006) as a ``perspective'' for Steinhardt and Turok's paper in the same issue (astro-ph/0605173).

Alexander Vilenkin

2006-05-09

301

Is vacuum dispersive?  

E-print Network

The question we ask is: does the speed of light {\\it{in vacuo}} depend on its frequency? While the answer is NO in the frame of classical physics, we point out that the opposite could be true if one takes into account the polarization of Dirac sea. We estimate the dependence of the index of refraction of vacuum + Dirac sea versus the wavelength of an incoming beam, and suggest a way to test this effect.

Yves Pomeau

2014-09-02

302

Spinning out of control: Wall turbulence over rotating discs  

NASA Astrophysics Data System (ADS)

The friction drag reduction in a turbulent channel flow generated by surface-mounted rotating disc actuators is investigated numerically. The wall arrangement of the discs has a complex and unexpected effect on the flow. For low disc-tip velocities, the drag reduction scales linearly with the percentage of the actuated area, whereas for higher disc-tip velocity, the drag reduction can be larger than the prediction found through the linear scaling with the actuated area. For medium disc-tip velocities, all the cases which display this additional drag reduction exhibit stationary-wall regions between discs along the streamwise direction. This effect is caused by the viscous boundary layer which develops over the portions of stationary wall due to the radial flow produced by the discs. For the highest disc-tip velocity, the drag reduction even increases by halving the number of discs. The power spent to activate the discs is instead independent of the disc arrangement and scales linearly with the actuated area for all disc-tip velocities. The Fukagata-Iwamoto-Kasagi identity and flow visualizations are employed to provide further insight into the dynamics of the streamwise-elongated structures appearing between discs. Sufficient interaction between adjacent discs along the spanwise direction must occur for the structures to be created at the disc side where the wall velocity is directed in the opposite direction to the streamwise mean flow. Novel half-disc and annular actuators are investigated to improve the disc-flow performance, resulting in a maximum of 26% drag reduction.

Wise, Daniel J.; Alvarenga, Claudia; Ricco, Pierre

2014-12-01

303

The LHC Vacuum System  

NASA Astrophysics Data System (ADS)

The Large Hadron Collider (LHC) at CERN, involves two proton storage rings with colliding beams of 7 TeV. The machine will be housed in the existing LEP tunnel and requires 16 m long superconducting bending magnets. The vacuum chamber will be the inner wall of the cryostat and hence at the temperature of the magnet cold bore, i.e. at 1.9 K and therefore a very good cryo-pump. To reduce the cryogenic power consumption, the heat load from synchrotron radiation and from the image currents in the vacuum chamber will be absorbed on a 'beam screen', which operates between 5 and 20 K, inserted in the magnet cold bore. The design pressure necessary for operation must provide a lifetime of many days and a stringent requirement comes from the power deposition in the superconducting magnet coils due to protons scattered on the residual gas which could lead to a magnet quench. Cryo-pumping of gas on the cold surfaces provides the necessary low gas densities but it must be ensured that the vapour pressure of cryo-sorbed molecules, of which H2 and He would be the most critical species, remains within acceptable limits. The room temperature sections of the LHC, specifically in the experiments, the vacuum must be stable against ion induced desorption and ISR-type 'pressure bumps'.

Gröbner, O.

1997-05-01

304

Effect of intervertebral disc degeneration on disc cell viability: a numerical investigation.  

PubMed

Degeneration of the intervertebral disc may be initiated and supported by impairment of the nutrition processes of the disc cells. The effects of degenerative changes on cell nutrition are, however, only partially understood. In this work, a finite volume model was used to investigate the effect of endplate calcification, water loss, reduction of disc height and cyclic mechanical loading on the sustainability of the disc cell population. Oxygen, lactate and glucose diffusion, production and consumption were modelled with non-linear coupled partial differential equations. Oxygen and glucose consumption and lactate production were expressed as a function of local oxygen concentration, pH and cell density. The cell viability criteria were based on local glucose concentration and pH. Considering a disc with normal water content, cell death was initiated in the centre of the nucleus for oxygen, glucose, and lactate diffusivities in the cartilaginous endplate below 20% of the physiological values. The initial cell population could not be sustained even in the non-calcified endplates when a reduction of diffusion inside the disc due to water loss was modelled. Alterations in the disc shape such as height loss, which shortens the transport route between the nutrient sources and the cells, and cyclic mechanical loads, could enhance cell nutrition processes. PMID:21970697

Galbusera, Fabio; Mietsch, Antje; Schmidt, Hendrik; Wilke, Hans-Joachim; Neidlinger-Wilke, Cornelia

2013-01-01

305

Joint Nonparametric Alignment for Analyzing Spatial Gene Expression Patterns in Drosophila Imaginal Discs  

E-print Network

or computer. Many dipteran organisms, including the fruit fly Drosophila melanogaster, have a three-stage life. First row: wing discs, second row: haltere discs, third row: leg discs, fourth row: eye discs

Sastry, S. Shankar

306

Disc valve for sampling erosive process streams  

DOEpatents

A four-port disc valve is described for sampling erosive, high temperature process streams. A rotatable disc defining opposed first and second sampling cavities rotates between fired faceplates defining flow passageways positioned to be alternatively in axial alignment with the first and second cavities. Silicon carbide inserts and liners composed of [alpha] silicon carbide are provided in the faceplates and in the sampling cavities to limit erosion while providing lubricity for a smooth and precise operation when used under harsh process conditions. 1 fig.

Mrochek, J.E.; Dinsmore, S.R.; Chandler, E.W.

1986-01-07

307

Hard Discs on the Hyperbolic Plane  

E-print Network

We examine a simple hard disc fluid with no long range interactions on the two dimensional space of constant negative Gaussian curvature, the hyperbolic plane. This geometry provides a natural mechanism by which global crystalline order is frustrated, allowing us to construct a tractable model of disordered monodisperse hard discs. We extend free area theory and the virial expansion to this regime, deriving the equation of state for the system, and compare its predictions with simulation near an isostatic packing in the curved space.

Carl D. Modes; Randall D. Kamien

2007-11-30

308

Fractured occluder disc: a previously unrecognized complication of the Starr-Edwards disc prosthesis.  

PubMed

Fracture of the occluder disc of a low-profile Starr-Edwards prosthesis is a hitherto unrecognized complication. We describe a patient who presented with right heart failure and severe pulmonary hypertension 27 years after mitral valve replacement with a model 6520 caged-disc prosthesis. At surgery, there was a longitudinal split in the occluder disc, and organized thrombus was lodged between the split segments. This case offers a unique opportunity to study the long-term effects of wear on the polyethylene poppet and Stellite cage. PMID:11206761

Malouf, J F; Hannoush, H M; Odell, J A

2001-01-01

309

Instabilities in Circumstellar Discs Charles F. Gammie 1  

E-print Network

Instabilities in Circumstellar Discs Charles F. Gammie 1 Isaac Newton Institute, 20 Clarkson Rd is governed by angular momentum transport; without torques the disc gas would remain in orbit and not accrete

Gammie, Charles F.

310

[Recognizing the pitfalls. Non-glaucomatous optic disc cupping].  

PubMed

Pathological optic disc cupping is most often caused by open angle glaucoma. More rarely, other optic neuropathies may be associated with acquired pathological optic disc cupping, sometimes mimicking glaucoma. A careful interpretation of the history, optic disc characteristics and visual fields are the main tools in the decision process of glaucomatous versus non-glaucomatous optic disc cupping, avoiding inappropriate, expensive neuroimaging examinations. PMID:17646798

Milea, D

2007-05-01

311

Symptomatic lumbar disc protrusion causing progressive myelopathy in a low-lying cord.  

PubMed

Low-lying cord is an uncommon entity, and cord compression due lumbar disc disease is rarely encountered. We discuss our experience with a case of lumbar cord compression secondary to a large disc protrusion, which caused myelopathy in a low-lying/tethered cord. A 77-year-old woman with known spina bifida occulta presented with 6-week history of severe low back pain and progressive paraparesis. Magnetic resonance imaging showed a low-lying tethered cord and a large disc prolapse at L2/3 causing cord compression with associated syringomyelia. Medical comorbidities precluded her from anterior decompression, and therefore a posterior decompression was performed. She recovered full motor power in her lower limbs and could eventually walk unaided. She had a deep wound infection, which was successfully treated with debridement, negative pressure therapy (vacuum-assisted closure pump), and antibiotics. Six months after surgery, her Oswestry Disability Index improved from 55% preoperatively to 20%. Posterior spinal cord decompression for this condition has been successful in our case, and we believe that the lumbar lordosis may have helped indirectly decompress the spinal cord by posterior decompression alone. PMID:24353956

Srinivas, Shreya; Shetty, Rohit; Collins, Iona

2012-06-01

312

DISC1 as a therapeutic target for mental illnesses  

PubMed Central

Introduction Many genetic studies have indicated that DISC1 is not merely “disrupted-in-schizophrenia,” but is more generally implicated in various brain dysfunctions associated with aberrant neurodevelopment and intracellular signaling pathways. Thus, the DISC1 gene is mildly associated with a variety of brain disorders, including schizophrenia, mood disorders, and autism. This novel concept fits with the results from biological studies of DISC1, which include cell and animal models. Areas covered We review the molecular structure and functions of DISC1, particularly those in conjunction with its important interactors. Functions of these interacting proteins are also introduced under the concept of the “DISC1 interactome.” Finally, we discuss how the DISC1 interactome can provide potential therapeutic targets for mental illnesses. Expert opinion Modulation of DISC1 stability and post-transcriptional modifications may be key targets to address DISC1-related pathology. In addition, modulation of DISC1 interactors and the mechanisms of their interactions with DISC1 may also provide drug targets. Disc1 rodent models can subsequently be used as templates for in vivo validations of compounds designed for DISC1 and its interacting proteins. Furthermore, these rodents will serve as genetic models for schizophrenia and related conditions, especially in conjunction with their pathologies during the neurodevelopmental trajectory. PMID:23130881

Hikida, Takatoshi; Gamo, Nao J.; Sawa, Akira

2014-01-01

313

Influences of osteoporosis and disc degeneration on lumbar spinal stability  

Microsoft Academic Search

Disc degeneration and osteoporosis are two main factors affecting the elderly and impacting the quality of life. The aims of this study were to provide the information on mechanical changes resulting from disc degeneration and osteoporosis and further to understand their roles in segmental instability. The influences of disc degeneration and osteoporosis were investigated using a 3?dimensional finite element model

2003-01-01

314

Transforaminal Epidural Clonidine versus Corticosteroid for Acute Lumbosacral Radiculopathy due to Intervertebral Disk Herniation  

PubMed Central

Study Design Randomized, double-blinded trial clinical trial. Objective To compare efficacies of 2 active therapies for chronic low back pain. Summary of Background Data Radicular pain may result from intervertebral disk herniation (IDH). Clonidine has demonstrated analgesic and antiinflammatory activity in animal studies of nerve injury. Extensive clinical experience supports neuraxial clonidine's safety. Methods Patients with ˜3 months of low back and leg pain due to IDH were randomized to transforaminal epidural (TFE) injection(s) of 2% lidocaine and either clonidine (200 or 400mcg) or triamcinolone (40mg). Patients received 1- 3 injections administered about 2 weeks apart. Patients, investigators and study coordinators were blinded to treatment. Primary outcome was 11-point Pain Intensity Numerical Rating Scale (PI-NRS) at 1 month. Other outcomes included Patient Global Impression of Change (PGIC), and functional measures. Results Thirty-three patients were screened and randomized. Twenty-six patients enrolled; 11 received clonidine and 15 triamcinolone. Both groups showed significant improvement in pain score at 2 weeks and 1 month compared to baseline (p< 0.05). The corticosteroid group showed additional functional improvement at 1 month relative to clonidine (p=0.022). There was no difference between groups for primary outcome. However, as target enrollment was not reached, we cannot say with confidence that the 2 treatments would be expected to result in similar short-term pain relief. Side-effects were common in both groups, but there were no serious complications. Conclusions Radicular pain due to IDH improved rapidly with TFE injection of either clonidine or triamcinolone. Corticosteroid resulted in greater functional improvement, with unclear differences in analgesia. Future studies will determine if clonidine is superior to placebo and of particular use in those at risk for corticosteroid complications. PMID:21192304

Burgher, Abram H.; Hoelzer, Bryan C.; Schroeder, Darrell R.; Wilson, Gregory A.; Huntoon, Marc A.

2010-01-01

315

Herniation Pits in Human Mummies: A CT Investigation in the Capuchin Catacombs of Palermo, Sicily  

PubMed Central

Herniation pits (HPs) of the femoral neck were first described in a radiological publication in 1982 as round to oval radiolucencies in the proximal superior quadrant of the femoral neck on anteroposterior radiographs of adults. In following early clinical publications, HPs were generally recognized as an incidental finding. In contrast, in current clinical literature they are mentioned in the context of femoroacetabular impingement (FAI) of the hip joint, which is known to cause osteoarthritis (OA). The significance of HPs in chronic skeletal disorders such as OA is still unclear, but they are discussed as a possible radiological indicator for FAI in a large part of clinical studies. In this paleoradiological study we examined a sample of mummies from the Capuchin Catacombs of Palermo, Sicily, by a mobile computed tomography (CT) scanner. Evaluation of the CT examinations revealed HPs in six out of 16 (37.5%) adult male mummies. The first aim of this study was to compare the characteristics of HPs shown in our mummy collection to the findings described in clinical literature. Thereby CT evaluation revealed that their osseous imaging characteristics are in accordance, consisting of round to oval subcortical lesions at the anterior femoral neck, clearly demarcated by a sclerotic margin. The second aim was to introduce HPs to the paleoradiological and paleopathological methodology as an entity that underwent a renaissance from an incidental finding to a possible radiological indicator of FAI in the clinical situation. As FAI plays an important role in the development of OA of the hip, which is a very common finding in human skeletal remains, HPs should always be considered in paleoradiological evaluation of hip joint diseases. PMID:22567164

Panzer, Stephanie; Piombino-Mascali, Dario; Zink, Albert R.

2012-01-01

316

Avoiding Death by Vacuum  

NASA Astrophysics Data System (ADS)

The two-Higgs doublet model (2HDM) can have two electroweak breaking, CP-conserving, minima. The possibility arises that the minimum which corresponds to the known elementary particle spectrum is metastable, a possibility we call the "panic vacuum". We present analytical bounds on the parameters of the softly broken Peccei-Quinn 2HDM which are necessary and sufficient conditions to avoid this possibility. We also show that, for this particular model, the current LHC data already tell us that we are necessarily in the global minimum of the theory, regardless of any cosmological considerations about the lifetime of the false vacua.

Barroso, A.; Ferreira, P. M.; Ivanov, I.; Santos, R.; Silva, João P.

2013-07-01

317

What is vacuum?  

E-print Network

Vacuum can be defined with exact mathematical precision as the state which remains when a fermion, with all its special characteristics, is created out of absolutely nothing. The definition leads to a special form of relativistic quantum mechanics, which only requires the construction of a creation operator. This form of quantum mechanics is especially powerful for analytic calculation, at the same time as explaining, from first principles, many aspects of the Standard Model of particle physics. In particular, the characteristics of the weak, strong and electric interactions can be derived from the structure of the creation operator itself.

Peter Rowlands

2008-10-01

318

Artificial Cervical Disc Replacement Improves Mobility  

MedlinePLUS Videos and Cool Tools

... see it gets inserted, it’s very rough. It’s titanium plasma sprayed, and this allows for the body ... the ProDisc C implant have a plasma-sprayed titanium coding to provide bony coating to promote bony ...

319

The Astral Curved Disc of Chevroches (France)  

NASA Astrophysics Data System (ADS)

The excavation of the unexplored secondary agglomeration in Chevroches (Nièvre), from 2001 to 2002, directed by F. Devevey (INRAP), has led to the discovery of an astrological bronze curved disc of a type unknown in the ancient world; it is inscribed with three lines in Greek transcribing Egyptian an Roman months, and the twelve signs of the zodiac. This article presents the first observations.

Devevey, F. Rousseau, A.

2009-08-01

320

The Substitution-Elimination Mechanistic Disc Method  

ERIC Educational Resources Information Center

A method designed to facilitate prediction of mechanism and products by developing critical thinking skills and reducing memorization is presented. The mechanistic disc method requiring students to utilize their understanding of charge stabilization, structural organic chemistry, and the fundamental mechanisms of aliphatic substitution and…

Buonora, Paul T.; Yu Jin Lim

2004-01-01

321

Metamorphosis of imaginal discs of Drosophila melanogaster  

Microsoft Academic Search

Imaginal discs ofDrosophila melanogaster larvae, 24–53 hrs after oviposition, were transplanted into mature immobile larval hosts. The transplants did not respond to the hormonal stimuli of metamorphosis, but instead completed their larval development. When reinjected into mature larval hosts, they now differentiated the full set of their presumptive imaginal structures. The process of acquiring competence for metamorphosis appears to be

Géza Mindek

1972-01-01

322

Disc Turbulence and Viscosity By AXEL BRANDENBURG  

E-print Network

. Introduction Accretion discs are a bit like waterfalls. Potential energy gets converted into kinetic stream splashes to the bottom. Equating the change of internal energy, c v ffiT , with the potential energy difference suggests a temperature increase ffiT of only 0.1 Kelvin. This is of course consistent

Brandenburg, Axel

323

Global Structure of Magnetorotationally Turbulent Protoplanetary Discs  

E-print Network

The aim of the present paper is to investigate the spatial structure of a protoplanetary disc whose dynamics is governed by magnetorotational turbulence. We perform a series of local 3D chemo-radiative MHD simulations located at different radii of a disc which is twice as massive as the standard minimum mass solar nebula of Hayashi (1981). The ionisation state of the disc is calculated by including collisional ionisation, stellar X-rays, cosmic rays and the decay of radionuclides as ionisation sources, and by solving a simplified chemical network which includes the effect of the absorption of free charges by {\\mu}m-sized dust grains. In the region where the ionisation is too low to assure good coupling between matter and magnetic fields, a non-turbulent central "dead zone" forms, which ranges approximately from a distance of 2 AU to 4 AU from the central star. The approach taken in the present work allows for the first time to derive the global spatial structure of a protoplanetary disc from a set of physical...

Flaig, M; Kley, W; Kissmann, R

2011-01-01

324

Rossby-wave instability in viscous discs  

NASA Astrophysics Data System (ADS)

Rossby-wave instability (RWI), which depends on density bumps and extrema in the vortensities of differentially rotating discs, plays an important role in the evolution of protoplanetary discs. In this article, we investigate the effect of viscosity on non-axisymmetric RWI in self-graviting accretion discs. For this purpose, we add viscosity to the work of Lovelace & Hohlfeld. Consideration of viscosity complicates the problem, so we use a numerical method to investigate stable and unstable modes. We consider three ranges of viscosity: high viscosity in the range 0.1 ? ? ? 0.4, moderate viscosity in the range 0.01 ? ? < 0.1 and low viscosity in the range ? < 0.01. The results show that the occurrence of RWI is related to the value of viscosity, so that the effect of high viscosity is important, while low viscosity is negligible. These results may be applied to the study of the role of RWI in planet formation and angular momentum transport for different kinds of protoplanetary discs with different viscosities.

Gholipour, Mahmoud; Nejad-Asghar, Mohsen

2014-07-01

325

Grain size segregation in debris discs  

NASA Astrophysics Data System (ADS)

Context. In most debris discs, dust grain dynamics is strongly affected by stellar radiation pressure. Because this mechanism is size-dependent, we expect dust grains to be spatially segregated according to their sizes. However, because of the complex interplay between radiation pressure, grain processing by collisions, and dynamical perturbations, this spatial segregation of the particle size distribution (PSD) has proven difficult to investigate and quantify with numerical models. Aims: We propose to thoroughly investigate this problem by using a new-generation code that can handle some of the complex coupling between dynamical and collisional effects. We intend to explore how PSDs behave in both unperturbed discs at rest and in discs pertubed by planetary objects. Methods: We used the DyCoSS code to investigate the coupled effect of collisions, radiation pressure, and dynamical perturbations in systems that have reached a steady-state. We considered two setups: a narrow ring perturbed by an exterior planet, and an extended disc into which a planet is embedded. For both setups we considered an additional unperturbed case without a planet. We also investigated the effect of possible spatial size segregation on disc images at different wavelengths. Results: We find that PSDs are always spatially segregated. The only case for which the PSD follows a standard dn ? s-3.5ds law is for an unperturbed narrow ring, but only within the parent-body ring itself. For all other configurations, the size distributions can strongly depart from such power laws and have steep spatial gradients. As an example, the geometrical cross-section of the disc is very rarely dominated by the smallest grains on bound orbits, as it is expected to be in standard PSDs in sq with q ? -3. Although the exact profiles and spatial variations of PSDs are a complex function of the set-up that is considered, we are still able to derive some reliable results that will be useful for image or SED-fitting models of observed discs.

Thebault, P.; Kral, Q.; Augereau, J.-C.

2014-01-01

326

Thermal and Optical Properties of Metal Azo Dyes for Digital Video Disc-Recordable Discs  

Microsoft Academic Search

The effects of the optical and thermal properties of metal azo dyes on the recording characteristics of digital video disc-recordable (DVD-R) discs have been studied. A sharp threshold for thermal decomposition of the dye assures a clear mark edge and low jitter for the minimum mark length of 0.4 0.44 µm. A steep absorption edge at the 635 nm side

Yuki Suzuki; Michikazu Horie; Yuuko Okamoto; Yutaka Kurose; Shuichi Maeda

1998-01-01

327

Enhancement of Overgrowth by Gene Interactions in Lethal(2)giant Discs Imaginal Discs from Drosophila Melanogaster  

PubMed Central

Recessive lethal mutations of the lethal(2)giant discs (l(2)gd) and lethal(2)fat (l(2)ft) loci of Drosophila melanogaster cause imaginal disc hyperplasia during a prolonged larval stage. Imaginal discs from l(2)ft l(2)gd or Gl(2)gd double homozygotes show more extensive overgrowth than in either single homozygote, and double homozygous l(2)ft l(2)gd mitotic clones in adult flies show much more overgrowth than is seen in clones homozygous for either l(2)gd or l(2)ft alone. dachsous (ds) also acts as an enhancer of l(2)gd, producing dramatically overgrown discs and causing failure to pupariate in double homozygotes. The comb gap (cg) mutation, which also interacts with ds, greatly enhances the tendency of imaginal discs from l(2)gd larvae to duplicate as they overgrow. If l(2)gd homozygotes are made heterozygous for l(2)ft, then several discs duplicate, indicating that l(2)ft acts as a dominant enhancer of l(2)gd. l(2)ft also acts as a dominant enhancer of l(2)gd, and conversely l(2)gd acts as a dominant modifier of l(2)ft. The enhancement of overgrowth caused by various mutant combinations is accompanied by changes in expression of Decapentaplegic and Wingless. These results show that tumor suppressor genes act in combination to control cell proliferation, and that tissue hyperplasia can be associated with ectopic expression of genes involved in pattern formation. PMID:9335602

Buratovich, M. A.; Bryant, P. J.

1997-01-01

328

Coupling effects of disc flexibility on the dynamic behaviour of multi disc-shaft systems  

NASA Astrophysics Data System (ADS)

The dynamic behaviour of a rotor consisting of multidiscs on a solid or hollow shaft, as used in gas or steam turbines, is considered. The effect of shaft flexibility on the dynamic characteristics of the discs and the coupling effects between the shaft and disc modes are investigated. The influence of the disc flexibility on the shaft system is also investigated. A new, thick, three-dimensional, cylindrical element is developed for the dynamic analysis and applied to various geometry of the discs-shaft system. Advantage is fully taken in the analysis of the rotational periodicity of the wave propagation. Results presented for various cases with differing flexibility and geometry show clearly the coupling effects in a multi disc-shaft system. Inference diagrams are developed, from which the dynamic behaviour of a system can be predicted for differing flexibility relationships between the solid or hollow shafts and the discs. The effect of various fixing conditions and boundary conditions on the coupling characteristics are also presented. The theoretical results show very close agreement with the experimental results.

Shahab, A. A. S.; Thomas, J.

1987-05-01

329

R&D ERL: Vacuum  

SciTech Connect

The ERL Vacuum systems are depicted in a figure. ERL has eight vacuum volumes with various sets of requirements. A summary of vacuum related requirements is provided in a table. Five of the eight volumes comprise the electron beamline. They are the 5-cell Superconducting RF Cavity, Superconducting e-gun, injection, loop and beam dump. Two vacuum regions are the individual cryostats insulating the 5-cell Superconducting RF Cavity and the Superconducting e-gun structures. The last ERL vacuum volume not shown in the schematic is the laser transport line. The beamline vacuum regions are separated by electropneumatic gate valves. The beam dump is common with loop beamline but is considered a separate volume due to geometry and requirements. Vacuum in the 5-cell SRF cavity is maintained in the {approx}10{sup -9} torr range at room temperature by two 20 l/s ion pumps and in the e-gun SRF cavity by one 60 l/s ion pump. Vacuum in the SRF cavities operated at 2{sup o}K is reduced to low 10{sup -11} torr via cryopumping of the cavity walls. The cathode of the e-gun must be protected from poisoning, which can occur if vacuum adjacent to the e-gun in the injection line exceeds 10-11 torr range in the injection warm beamline near the e-gun exit. The vacuum requirements for beam operation in the loop and beam dump are 10-9 torr range. The beamlines are evacuated from atmospheric pressure to high vacuum level with a particulate free, oil free turbomolecular pumping cart. 25 l/s shielded ion pumps distributed throughout the beamlines maintain the vacuum requirement. Due to the more demanding vacuum requirement of the injection beamline proximate to the e-gun, a vacuum bakeout of the injection beamline is required. In addition, two 200 l/s diode ion pumps and supplemental pumping provided by titanium sublimation pumps are installed in the injection line just beyond the exit of the e-gun. Due to expected gas load a similar pumping arrangement is planned for the beam dump. The cryostat vacuum thermally insulating the SRF cavities need only reduce the convective heat load such that heat loss is primarily radiation through several layers of multi-layer insulation and conductive end-losses which are contained by 5{sup o}K thermal transitions. Prior to cool down rough vacuum {approx}10{sup -5} torr range is established and maintained by a dedicated turbomolecular pump station. Cryopumping by the cold mass and heat shields reduces the insulating vacuum to 10{sup -7} torr range after cool down.

Mapes, M.; Smart, L.; Weiss, D.; Steszyn, A.; Todd, R.

2010-01-01

330

Collisional dust avalanches in debris discs  

E-print Network

We quantitatively investigate how collisional avalanches may developin debris discs as the result of the initial break-up of a planetesimal or comet-like object, triggering a collisional chain reaction due to outward escaping small dust grains. We use a specifically developed numerical code that follows both the spatial distribution of the dust grains and the evolution of their size-frequency distribution due to collisions. We investigate how strongly avalanche propagation depends on different parameters (e.g., amount of dust released in the initial break-up, collisional properties of dust grains and their distribution in the disc). Our simulations show that avalanches evolve on timescales of ~1000 years, propagating outwards following a spiral-like pattern, and that their amplitude exponentially depends on the number density of dust grains in the system. We estimate a probability for witnessing an avalanche event as a function of disc densities, for a gas-free case around an A-type star, and find that features created by avalanche propagation can lead to observable asymmetries for dusty systems with a beta Pictoris-like dust content or higher. Characteristic observable features include: (i) a brightness asymmetry of the two sides for a disc viewed edge-on, and (ii) a one-armed open spiral or a lumpy structure in the case of face-on orientation. A possible system in which avalanche-induced structures might have been observed is the edge-on seen debris disc around HD32297, which displays a strong luminosity difference between its two sides.

Anna Grigorieva; Pawel Artymowicz; Philippe Thébault

2006-09-01

331

Stellar orbit evolution in close circumstellar disc encounters  

NASA Astrophysics Data System (ADS)

The formation and early evolution of circumstellar discs often occurs within dense, newborn stellar clusters. For the first time, we apply the moving-mesh code AREPO, to circumstellar discs in 3D, focusing on disc-disc interactions that result from stellar flybys. Although a small fraction of stars are expected to undergo close approaches, the outcomes of the most violent encounters might leave an imprint on the discs and host stars that will influence both their orbits and their ability to form planets. We first construct well-behaved 3D models of self-gravitating discs, and then create a suite of numerical experiments of parabolic encounters, exploring the effects of pericentre separation rp, disc orientation and disc-star mass ratio (Md/M*) on the orbital evolution of the host stars. Close encounters (2rp ? disc radius) can truncate discs on very short time-scales. If discs are massive, close encounters facilitate enough orbital angular momentum extraction to induce stellar capture. We find that for realistic primordial disc masses Md ? 0.1M*, non-colliding encounters induce minor orbital changes, which is consistent with analytic calculations of encounters in the linear regime. The same disc masses produce entirely different results for grazing/colliding encounters. In the latter case, rapidly cooling discs lose orbital energy by radiating away the energy excess of the shock-heated gas, thus causing capture of the host stars into a bound orbit. In rare cases, a tight binary with a circumbinary disc forms as a result of this encounter.

Muñoz, D. J.; Kratter, K.; Vogelsberger, M.; Hernquist, L.; Springel, V.

2015-01-01

332

The vacuum arc centrifuge  

NASA Astrophysics Data System (ADS)

The separation of elements and isotopes by means of rotating magnetized plasma columns using a laser-triggered vacuum arc centrifuge is described. This vacuum arc centrifuge is sustained by the erosion and ionization of the cathode material, thus producing relatively pure, highly ionized, rotating plasma columns of the cathode material. Any solid metal, or mixture of metals, can be converted into plasma, and the constituent isotopes partially separated in the centrifuge, by fabricating the arc cathode out of the desired metals. The device also offers the possibility of operation with nonconducting solid elements or compounds by imbedding the desired substance in a conducting matrix. A wide variety of metals and combinations of metals were studied, ranging from C through Cu to Cd/Sn. Typical angular rotation frequencies of approx. 100,000 rad/sec were measured, with concomitant enrichments up to a factor of two for Cu 65. The device in its present form is not a viable source of partially enriched stable isotopes at a competitive cost.

Krishnan, M.; Hirshfield, J. L.

333

The LHC Vacuum System  

E-print Network

The Large Hadron Collider (LHC) at CERN, involves two proton storage rings with colliding beams of 7 TeV. The machine will be housed in the existing LEP tunnel and requires 16 m long superconducting b ending magnets. The vacuum chamber will be the inner wall of the cryostat and hence at the temperature of the magnet cold bore, i.e. at 1.9 K and therefore a very good cryopump. To reduce the cryogeni c power consumption, the heat load from synchrotron radiation and from the image currents in the vacuum chamber will be absorbed on a 'beam screen', which operates between 5 and 20 K, inserted in the magnet cold bore. The design pressure necessary for operation must provide a lifetime of several days and a further stringent requirement comes from the power deposition in the superconducting magnet coils due to protons scattered on the residual gas which could lead to a magnet quench. Cryopumping of gas on the cold surfaces provides the necessary low gas densities but it must be ensured that the vapour pressure of cr...

Gröbner, Oswald

1998-01-01

334

LHC vacuum system  

E-print Network

The Large Hadron Collider (LHC) project, now in the advanced construction phase at CERN, comprises two proton storage rings with colliding beams of 7-TeV energy. The machine is housed in the existing LEP tunnel with a circumference of 26.7 km and requires a bending magnetic field of 8.4 T with 14-m long superconducting magnets. The beam vacuum chambers comprise the inner 'cold bore' walls of the magnets. These magnets operate at 1.9 K, and thus serve as very good cryo-pumps. In order to reduce the cryogenic power consumption, both the heat load from synchrotron radiation emitted by the proton beams and the resistive power dissipation by the beam image currents have to be absorbed on a 'beam screen', which operates between 5 and 20 K and is inserted inside the vacuum chamber. The design of this beam screen represents a technological challenge in view of the numerous and often conflicting requirements and the very tight mechanical tolerances imposed. The synchrotron radiation produces strong outgassing from the...

Gröbner, Oswald

1999-01-01

335

Vacuum disconnectors an application study  

Microsoft Academic Search

The ageing of vacuum interrupters with combined functions of disconnector and circuit-breaker or switch is studied for compact shielded solid insulated switchgear. Different prototypes are manufactured to investigate the influence of contact materials and contact designs. A test program is presented that realistically represents the ageing as described in the standards. The feasibility to create vacuum disconnecting circuit-breakers, vacuum switch-disconnectors

H. Schellekens; T. Shioiri; M. Homma; P. Picot; K. Sasage; D. Mazzucchi

2010-01-01

336

Portable vacuum object handling device  

DOEpatents

The disclosure relates to a portable device adapted to handle objects which are not to be touched by hand. A piston and bore wall form a vacuum chamber communicating with an adaptor sealably engageable with an object to be lifted. The piston is manually moved and set to establish vacuum. A valve is manually actuatable to apply the vacuum to lift the object. 1 fig.

Anderson, G.H.

1983-08-09

337

Low partial discharge vacuum feedthrough  

NASA Technical Reports Server (NTRS)

Relatively discharge free vacuum feedthrough uses silver-plated copper conductor jacketed by carbon filled silicon semiconductor to reduce concentrated electric fields and minimize occurrence of partial discharge.

Benham, J. W.; Peck, S. R.

1979-01-01

338

Vacuum insulation on the moon  

NASA Astrophysics Data System (ADS)

This paper presents recent concepts and analysis on vacuum insulation issues in the lunar environment, including dust initiated breakdown, thermal management, gas contamination, and solar radiation effects.

Gordon, Lloyd B.; Gaustad, Krista L.

1994-05-01

339

Examination of turbine discs from nuclear power plants  

SciTech Connect

Investigations were performed on a cracked turbine disc from the Cooper Nuclear Power Station, and on two failed turbine discs (governor and generator ends) from the Yankee-Rowe Nuclear Power Station. Cooper is a boiling water reactor (BWR) which went into commercial operation in July 1974, and Yankee-Rowe is a pressurized water reactor (PWR) which went into commercial operation in June 1961. Cracks were identified in the bore of the Cooper disc after 41,913 hours of operation, and the disc removed for repair. At Yankee-Rowe two discs failed after 100,000 hours of operation. Samples of the Cooper disc and both Yankee-Rowe disc (one from the governor and one from the generator end of the LP turbine) were sent to Brookhaven National Laboratory (BNL) for failure analysis.

Czajkowski, C.J.; Weeks, J.R.

1982-01-01

340

Computer assisted characterization of cervical intervertebral disc degeneration in MRI  

NASA Astrophysics Data System (ADS)

A texture-based pattern recognition system is proposed for the automatic characterization of cervical intervertebral disc degeneration from saggital magnetic resonance images of the spine. A case sample of 50 manually segmented ROIs, corresponding to 25 normal and 25 degenerated discs, was analyzed and textural features were generated from each disc-ROI. Student's t-test verified the existence of statistically significant differences between textural feature values generated from normal and degenerated discs. This finding is indicative of disc image texture differentiation due to the degeneration of the disc. The generated features were employed in the design of a pattern recognition system based on the Least Squares Minimum Distance classifier. The system achieved a classification accuracy of 94{%} and it may be of value to physicians for the assessment of cervical intervertebral disc degeneration in MRI.

Michopoulou, S.; Boniatis, I.; Costaridou, L.; Cavouras, D.; Panagiotopoulos, E.; Panayiotakis, G.

2009-05-01

341

A novel classification system of lumbar disc degeneration.  

PubMed

The Pfirrmann and modified Pfirrmann grading systems are currently used to classify lumbar disc degeneration. These systems, however, do not incorporate variables that have been associated with lumbar disc degeneration, including Modic changes, a high intensity zone, and a significant reduction in disc height. A system that incorporates these variables that is easy to apply may be useful for research and clinical purposes. A grading system was developed that incorporates disc structure and brightness, presence or absence of Modic changes, presence or absence of a high intensity zone, and reduction in disc height (disc height less than 5mm). MRI of 300 lumbar discs in 60 patients were analyzed twice by two neurosurgeons. Intra and inter-observer reliabilities were assessed by calculating Cohen's ? values. There were 156 grade zero ("normal"), 50 grade one, 57 grade two, 26 grade three, 10 grade four, and one grade five ("worst") discs. Inter-observer reliability was substantial (?=0.66 to 0.77) for disc brightness/structure, Modic changes, and disc height. Inter-observer reliability was moderate (?=0.41) for high intensity zone. Intra-observer reliability was moderate to excellent (?=0.53 to 0.94) in all categories. Agreement on the total grade between reviewers occurred 71% of the time and a difference of one grade occurred in an additional 25% of cases. Lumbar disc degeneration can be graded reliably by this novel system. The advantage of this system is that it incorporates disc brightness/structure, Modic changes, high intensity zone, and a rigid definition of loss of disc height. This system might be useful in research studies evaluating disc degeneration. Further studies are required to demonstrate possible clinical utility in predicting outcomes after spinal treatments such as fusion. PMID:25443079

Riesenburger, Ron I; Safain, Mina G; Ogbuji, Richard; Hayes, Jackson; Hwang, Steven W

2015-02-01

342

Entrapment Type Vacuum Pumps  

NSDL National Science Digital Library

This is a description for a learning module from Maricopa Advanced Technology Education Center. This PDF describes the module; access may be purchased by visiting the MATEC website. Entrapment type pumps operate primarily in the high to ultra-high vacuum ranges. The discussion in this MATEC module includes applications, theory of operation, operating range and preventative maintenance. The focus is on three major types of pumps: cryosorption, cryogenic and sputter-ion. The overall performance of these types of pumps depends on a variety of parameters. For example, it is important that learners understand the balance between pumping speed and capacity. Competency is demonstrated as the learners specify systems for defined process applications.

343

Control Dewar Secondary Vacuum Container  

SciTech Connect

This engineering note provides background information regarding the control dewar secondary vacuum container. The secondary vacuum container has it's origin with the CDP control dewar design. The name secondary vacuum container replaced the CDP term 'Watt can' which was named after Bob Watt (SLAC), a PAC/DOE review committee member who participated in a review of CDP and recommended a secondary vacuum enclosure. One of the most fragile parts of the control dewar design is the ceramic electrical feed throughs located in the secondary vacuum container. The secondary vacuum container is provided to guard against potential leaks in these ceramic insulating feed throughs. The secondary vacuum container has a pumping line separate from the main solenoid/control dewar insulating vacuum. This pumping line is connected to the inlet of the turbo pump for initial pumpdown. Under normal operation the container is isolated. Should a feedthrough develop a small leak, alternate pumping arrangements for the secondary vacuum container could be arranged. The pressure in the secondary vacuum container should be kept in a range that the breakdown voltage is kept at a maximum. The breakdown voltage is known to be a function of pressure and is described by a Paschen curve. I cannot find a copy of the curve at this time, but from what I remember, the breakdown voltage is a minimum somewhere around 10-3 torr. Ideally the pressure in the secondary vacuum can should be kept very low, around 10 E-6 or 10 E-7 torr for maximum breakdown voltage. If however a leak developed and this was not possible, then one could operate at a pressure higher than the minima point.

Rucinski, R.; /Fermilab

1993-10-04

344

[Postpartum secondary cerebral venous sinus thrombosis with axial transtentorial and tonsillar herniation as a complication of intracranial hypotension syndrome after spinal anaesthesia].  

PubMed

We describe the case of a 28-year-old postpartum female patient who suffered from a secondary cerebral venous sinus thrombosis due to an intracranial hypotension syndrome with axial transtentorial and tonsillar herniation and the clinical signs of incarceration after spinal anaesthesia. PMID:25489758

Kraayvanger, L; Berlit, P

2014-12-01

345

Oxygen abundance distribution in the Galactic disc  

NASA Astrophysics Data System (ADS)

We performed a non-local thermodynamic equilibrium (NLTE) analysis of the infrared oxygen triplet for a large number of Cepheid spectra obtained with the Hobby-Eberly Telescope. These data were combined with our previous NLTE results for stars observed with the Max Planck Gesellschaft Telescope with the aim of investigating the oxygen abundance distribution in the Galactic thin disc. We found the slope of the radial (O/H) distribution to be equal -0.058 dex kpc-1. However, we found some evidence that the distribution might become flatter in the outer parts of the disc. This is supported by the results of other authors who have studied open clusters, planetary nebulae and H II regions. Some mechanisms of flattening are discussed.

Korotin, S. A.; Andrievsky, S. M.; Luck, R. E.; Lépine, J. R. D.; Maciel, W. J.; Kovtyukh, V. V.

2014-11-01

346

New Experiments with Spinning Metallic Discs  

NASA Technical Reports Server (NTRS)

A number of recent advanced theories related to torsion properties of the space-time matrix predict the existence of an interaction between classically spinning objects. Indeed, some experimental data suggest that spinning magnetic bodies discernibly interact with Earth's natural fields. If there are interactions between rotating bodies then nuclear spins could be used for detection. Thus, assuming a spinning body induces a hypothetical torsion field, a sensor based on the giant magnetoresistance effect would detect local changes. Experimentally, spinning a brass wheel shielded from Earth's magnetic field showed no measurable change in signals; with no shielding a Faraday disc phenomenon was observed. Unexpected experimental measurements from the non-axial Faraday disc configuration were recorded and a theoretical model was derived to explain them.

Mazuruk, Konstantin; Grugel, Richard N.

2003-01-01

347

Vacuum Gas Tungsten Arc Welding  

NASA Technical Reports Server (NTRS)

A two-year program investigated vacuum gas tungsten arc welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. After a vacuum chamber and GTAW power supply were modified, several difficult-to-weld materials were studied and key parameters developed. Finally, Incoloy 903 weld overlays were produced without microfissures.

Weeks, J. L.; Todd, D. T.; Wooten, J. R.

1997-01-01

348

Braneworld dynamics with vacuum polarization  

E-print Network

We investigate the cosmological dynamics of a brane Universe when quantum corrections from vacuum polarization are taken into account. New vacuum de Sitter points existing on Randall-Sundrum brane are described. We show also that quantum correction can destroy the DGP de Sitter solution on induced gravity brane.

A. V. Toporensky; P. V. Tretyakov

2005-12-15

349

Vacuum Enhanced Cutaneous Biopsy Instrument  

SciTech Connect

A syringe-like disposable cutaneous biopsy instrument equipped with a tubular blade at its lower end, and designed so that a vacuum is created during use, said vacuum serving to retain undeformed a plug of tissue cut from a patient's skin.

Collins, Joseph

1999-06-25

350

Detecting leaks in vacuum bags  

NASA Technical Reports Server (NTRS)

Small leaks in vacuum bag can be readily detected by eye, using simple chemical reaction: combination of ammonia and acetic acid vapors to produce cloudy white smoke. Technique has been successfully used to test seam integrity and to identify minute pinholes in vacuum bag used in assembly of ceramic-tile heat shield for Space Shuttle Orbiter.

Carlstrom, E. E.

1980-01-01

351

Vacuum flash evaporated polymer composites  

DOEpatents

A method for fabrication of polymer composite layers in a vacuum is disclosed. More specifically, the method of dissolving salts in a monomer solution, vacuum flash evaporating the solution, condensing the flash evaporated solution as a liquid film, and forming the condensed liquid film into a polymer composite layer on a substrate is disclosed.

Affinito, J.D.; Gross, M.E.

1997-10-28

352

On simplicity of vacuum modules  

Microsoft Academic Search

We find necessary and sufficient conditions of irreducibility of vacuum modules over affine Lie algebras and superalgebras. From this we derive conditions of simplicity of minimal W-algebras. Moreover, in the case of the Virasoro and Neveu–Schwarz algebras we obtain explicit formulas for the vacuum determinants.

Maria Gorelik; Victor Kac

2007-01-01

353

Purifying Aluminum by Vacuum Distillation  

NASA Technical Reports Server (NTRS)

Proposed method for purifying aluminum employs one-step vacuum distillation. Raw material for process impure aluminum produced in electrolysis of aluminum ore. Impure metal melted in vacuum. Since aluminum has much higher vapor pressure than other constituents, boils off and condenses on nearby cold surfaces in proportions much greater than those of other constituents.

Du Fresne, E. R.

1985-01-01

354

Statistical mechanics of the vacuum  

E-print Network

The vacuum is full of virtual particles which exist for short moments of time. In this paper we construct a chaotic model of vacuum fluctuations associated with a fundamental entropic field that generates an arrow of time. The dynamics can be physically interpreted in terms of fluctuating virtual momenta. This model leads to a generalized statistical mechanics that distinguishes fundamental constants of nature.

Christian Beck

2011-12-07

355

Vacuum enhanced cutaneous biopsy instrument  

DOEpatents

A syringe-like disposable cutaneous biopsy instrument equipped with a tubular blade at its lower end, and designed so that a vacuum is created during use, said vacuum serving to retain undeformed a plug of tissue cut from a patient's skin.

Collins, Joseph (St. Petersburg, FL)

2000-01-01

356

??????????????????????????????????????????? Vacuum Cooling Process of Lettuce  

Microsoft Academic Search

The aim of this research work is to study the moisture and the temperature variation of lettuce under vacuum cooling processes. The experiment was carried out in a rectangular vacuum chamber having a volume of 0.036 m3. The experimental results showed that the cooling rate at the first stage of running was considerably high. the chamber temperature profile during the

Phanlop Saranyachoet; Naris Pratinthong; Thanit Swasdisevi

357

Superresolution technology applied to optical discs  

NASA Astrophysics Data System (ADS)

Smaller focal points are essential for the development of the next-generation optical disc. The size of focal point depends on the diffraction effect that is dependant on the numerical aperture of a lens and the wavelength of light. However, increase of the numerical aperture and decrease of the light wavelength will be ultimately limited due to the technical difficulty of fabricating a too-high NA lens and the too-short wavelength laser. In this paper, we report another approach of using the superresolution technology to compress the size of the so-called Airy spot for the next-generation optical disc, which is independent on the wavelength of laser. The superresolution phase plates are designed and fabricated with a microoptics technique. When such a phase plate is inserted into the optical system, the central spot at the focal plane of a lens is decreased to be 0.8 times of the Airy pattern, implying the possibility of reading higher storage density of optical discs. The most attractive feature is that the phase plate can be mass-produced at a very low cost, compared with the high cost of the high-numerical lens and/or the short wavelength laser. The disadvantages are that the inserted phase plate will induce the slight circular sidelobes around the central sport, so that it consumes a little more laser energy. The shortcoming could be overcome with suitable amendment. We have fabricated the phase plates with the surface-relief profile on a normal glass for phase modulation. Experimental results of superresolution effect with a low numerical aperture (NA=0.1) and a high-numerical lens (NA=0.8) are reported, which are in good agreement with the theoretical prediction. Superresolution technique should be highly interesting as a novel technique of the next-generation pickup head for reading the high storage of the optical discs.

Zhou, Changhe; Luo, Hongxin

2005-09-01

358

Development of fluorescent multilayer disc structure  

NASA Astrophysics Data System (ADS)

The fluorescent multilayer disc (FMD) consists of a substrate and the sandwich-structure of information and intermediate layers. While all the structure of the disc is transparent and homogeneous the parasitic signal will be caused mostly by photoluminescence (PL) and absorption of pits areas where laser light is unfocused. At large number of layers (10 or more) the noise level will get significant value, so it was suggested to derive readout signal as a variable one. Also it was proposed to record information only by the lands, to decrease the absorbance level and thus uncontrolled changing of the noise level. Furthermore in the FMD information layer there are inner and outside peripheral areas which hold a stable level of parasitic signal during readout from the edges of the disc. While the PL readout signal is spatially isotropic the optical head of the FMD drive receives just a part of the probing beam energy. PL quantum yield, absorption factor, receiver systems exposure loss coefficients are other reasons of the low PL signal. Thus the problem of the low SNR in this case is a major one and the only way of its solving is synthesis of the dye with a high PL quantum yield. The PL relaxation time on the other hand is a main feature of the data reading rate and therefore selection of the appropriate recording material will allow to bring this parameter in accordance to parameters of modern optical discs. To achieve this goal the composite organic pyrazoline dyes where synthesized and investigated as effective medium with a PL quantum yield up to 60-70%, relaxation time less than 100 ns, PL wide spectrum and opportunity of two-photon absorption. These parameters were further improved by a method based on the performance of organic dye molecules in the zeolite matrix.

Beliak, Ievgen; Butenko, Larisa

2011-09-01

359

Inner disc obscuration in GRS 1915+105 based on relativistic slim disc model  

NASA Astrophysics Data System (ADS)

We study the observational signatures of the relativistic slim disc of 10 M? black hole, in a wide range of mass accretion rate, dot{m}, dimensionless spin parameter, a*, and viewing angle, i. In general, the innermost temperature, Tin, increases with the increase of i for a fixed value of dot{m} and a*, due to the Doppler effect. However, for i > 50° and dot{m}>dot{m}_turn, Tin starts to decrease with the increase of dot{m}. This is a result of self-obscuration - the radiation from the innermost hot part of the disc is blocked by the surrounding cooler part. The value of dot{m}_turn and the corresponding luminosities depend on a* and i. Such obscuration effects cause an interesting behaviour on the disc luminosity (Ldisc)-Tin plane for high inclinations. In addition to the standard disc branch which appears below dot{m}_turn and which obeys L_disc ? T_in4 relation, another branch above dot{m}_turn, which is nearly horizontal, may be observed at luminosities close to the Eddington luminosity. We show that these features are likely observed in a Galactic X-ray source, GRS 1915+105. We support a high spin parameter (a* > 0.9) for GRS 1915+105 since otherwise the high value of Tin and small size of the emitting region (rin < 1rS) cannot be explained.

Vierdayanti, K.; Sadowski, A.; Mineshige, S.; Bursa, M.

2013-11-01

360

Vacuum energy as dark matter  

NASA Astrophysics Data System (ADS)

We consider the vacuum energy of massive quantum fields in an expanding universe. We define a conserved renormalized energy-momentum tensor by means of a comoving cutoff regularization. Using exact solutions for de Sitter space-time, we show that in a certain range of mass and renormalization scales there is a contribution to the vacuum energy density that scales as nonrelativistic matter and that such a contribution becomes dominant at late times. By means of the WKB approximation, we find that these results can be extended to arbitrary Robertson-Walker geometries. We study the range of parameters in which the vacuum energy density would be compatible with current limits on dark matter abundance. Finally, by calculating the vacuum energy in a perturbed Robertson-Walker background, we obtain the speed of sound of density perturbations and show that the vacuum energy density contrast can grow on sub-Hubble scales as in standard cold dark matter scenarios.

Albareti, F. D.; Cembranos, J. A. R.; Maroto, A. L.

2014-12-01

361

Automatic Handling Mechanisms For An Optical Disc Mass Memory System  

NASA Astrophysics Data System (ADS)

An optical disc mass memory system is being developed which will provide automatic access to any data in a store of 1013 bits within five seconds. This system contains a library of 128 optical discs with mechanisms for retrieving any disc, loading it onto a turntable, and recording or playing digital data at a rate of 50 Mb/s. The optical discs are housed in protective cartridges to facilitate handling by the operating personnel and automatic disc handling mechanisms. Cartridges are moved from the store to a load station by a belt-driven X-Y transport mechanism. The load station then mounts the discs onto a precision turntable, and they are spun up to speed while housed within their protective cartridges. A window in the cartridge wall provides access for the record and play laser beams to operate on the disc media. The disc handling mechanisms were designed to minimize mechanical shock and vibration while providing a rapid, smooth operation. A special centering hub design, for the turntable minimizes disc eccentricities during multiple load/unload cycles and allows easy inter-changeability among machines. This paper will describe the cartridge, turntable, and disc handling mechanisms designs. Test results from an engineering model implementing these designs will also be presented.

Ammon, G. J.; Siryj, B. W.

1983-09-01

362

The origin and formation of the circumstellar disc  

NASA Astrophysics Data System (ADS)

The formation and evolution of the circumstellar disc in the collapsing molecular cloud with and without magnetic field is investigated from the pre-stellar stage resolving both the molecular cloud core and the protostar itself. In the collapsing cloud core, the first (adiabatic) core appears prior to the protostar formation. Reflecting the thermodynamics of the collapsing gas, the first core is much more massive than the protostar. When the molecular cloud has no angular momentum, the first core falls on to the protostar and disappears a few years after the protostar formation. On the other hand, when the molecular cloud has an angular momentum, the first core does not disappear even after the protostar formation, and directly evolves into the circumstellar disc with a Keplerian rotation. There are two paths for the formation of the circumstellar disc. When the initial cloud has a considerably small rotational energy, two nested discs appear just after the protostar formation. During the early main accretion phase, the inner disc increases its size and merges with the outer disc (i.e. first core) to form a single circumstellar disc with a Keplerian rotation. On the other hand, when the molecular cloud has a rotational energy comparable to observations, a single centrifugally supported disc that corresponds to the first core already exists prior to the protostar formation. In such a cloud, the first core density gradually increases, maintaining the Keplerian rotation and forms the protostar inside it. The magnetic field rarely affects the early formation of the circumstellar disc because the magnetic field dissipates in the high-density gas region where the circumstellar disc forms. As a result, in any case, the protostar at its formation is already surrounded by a massive circumstellar disc. The circumstellar disc is about 10-100 times more massive than the protostar in the main accretion phase. Such discs are favourable sites for the formation of binary companions and gas-giant planets.

Machida, Masahiro N.; Matsumoto, Tomoaki

2011-06-01

363

Macroscopic changes during negative pressure wound therapy of the open abdomen using conventional negative pressure wound therapy and NPWT with a protective disc over the intestines  

Microsoft Academic Search

Background  Higher closure rates of the open abdomen have been reported with negative pressure wound therapy (NPWT) than with other wound\\u000a management techniques. However, the method has occasionally been associated with increased development of fistulae. We have\\u000a previously shown that NPWT induces ischemia in the underlying small intestines close to the vacuum source, and that a protective\\u000a disc placed between the

Sandra Lindstedt; Malin Malmsjö; Johan Hansson; Joanna Hlebowicz; Richard Ingemansson

2011-01-01

364

Radiation magnetohydrodynamics in global simulations of protoplanetary discs  

NASA Astrophysics Data System (ADS)

Aims: Our aim is to study the thermal and dynamical evolution of protoplanetary discs in global simulations, including the physics of radiation transfer and magneto-hydrodynamic turbulence caused by the magneto-rotational instability. Methods: We have developed a radiative transfer method based on the flux-limited diffusion approximation that includes frequency dependent irradiation by the central star. This hybrid scheme is implemented in the PLUTO code. The focus of our implementation is on the performance of the radiative transfer method. Using an optimized Jacobi preconditioned BiCGSTAB solver, the radiative module is three times faster than the magneto-hydrodynamic step for the disc set-up we consider. We obtain weak scaling efficiencies of 70% up to 1024 cores. Results: We present the first global 3D radiation magneto-hydrodynamic simulations of a stratified protoplanetary disc. The disc model parameters were chosen to approximate those of the system AS 209 in the star-forming region Ophiuchus. Starting the simulation from a disc in radiative and hydrostatic equilibrium, the magneto-rotational instability quickly causes magneto-hydrodynamic turbulence and heating in the disc. We find that the turbulent properties are similar to that of recent locally isothermal global simulations of protoplanetary discs. For example, the rate of angular momentum transport ? is a few times 10-3. For the disc parameters we use, turbulent dissipation heats the disc midplane and raises the temperature by about 15% compared to passive disc models. The vertical temperature profile shows no temperature peak at the midplane as in classical viscous disc models. A roughly flat vertical temperature profile establishes in the optically thick region of the disc close to the midplane. We reproduce the vertical temperature profile with viscous disc models for which the stress tensor vertical profile is flat in the bulk of the disc and vanishes in the disc corona. Conclusions: The present paper demonstrates for the first time that global radiation magneto-hydrodynamic simulations of turbulent protoplanetary discs are feasible with current computational facilities. This opens up the window to a wide range of studies of the dynamics of the inner parts of protoplanetary discs, for which there are significant observational constraints.

Flock, M.; Fromang, S.; González, M.; Commerçon, B.

2013-12-01

365

Genetic and Functional Studies of the Intervertebral Disc: A Novel Murine Intervertebral Disc Model  

PubMed Central

Intervertebral disc (IVD) homeostasis is mediated through a combination of micro-environmental and biomechanical factors, all of which are subject to genetic influences. The aim of this study is to develop and characterize a genetically tractable, ex vivo organ culture model that can be used to further elucidate mechanisms of intervertebral disc disease. Specifically, we demonstrate that IVD disc explants (1) maintain their native phenotype in prolonged culture, (2) are responsive to exogenous stimuli, and (3) that relevant homeostatic regulatory mechanisms can be modulated through ex-vivo genetic recombination. We present a novel technique for isolation of murine IVD explants with demonstration of explant viability (CMFDA/propidium iodide staining), disc anatomy (H&E), maintenance of extracellular matrix (ECM) (Alcian Blue staining), and native expression profile (qRT-PCR) as well as ex vivo genetic recombination (mT/mG reporter mice; AdCre) following 14 days of culture in DMEM media containing 10% fetal bovine serum, 1% L-glutamine, and 1% penicillin/streptomycin. IVD explants maintained their micro-anatomic integrity, ECM proteoglycan content, viability, and gene expression profile consistent with a homeostatic drive in culture. Treatment of genetically engineered explants with cre-expressing adenovirus efficaciously induced ex vivo genetic recombination in a variety of genetically engineered mouse models. Exogenous administration of IL-1ß and TGF-ß3 resulted in predicted catabolic and anabolic responses, respectively. Genetic recombination of TGFBR1fl/fl explants resulted in constitutively active TGF-ß signaling that matched that of exogenously administered TGF-ß3. Our results illustrate the utility of the murine intervertebral disc explant to investigate mechanisms of intervertebral disc degeneration. PMID:25474689

Pelle, Dominic W.; Peacock, Jacqueline D.; Schmidt, Courtney L.; Kampfschulte, Kevin; Scholten, Donald J.; Russo, Scott S.; Easton, Kenneth J.; Steensma, Matthew R.

2014-01-01

366

Vacuum phenomenon: Clinical relevance.  

PubMed

Vacuum phenomenon (VP) is an anatomical entity of potential confusion in the diagnosis and evaluation of joint pathology. Observation of this phenomenon has been demonstrated on basic radiographs, computed tomography, and magnetic resonance imaging. Although VP is most often associated with degenerative joint disease, it is observed with other pathologies. Two problematic scenarios can occur: a false-positive diagnosis of serious pathology instead of benign VP and a false-negative diagnosis of benign VP with a more serious underlying process Despite this potential for confusion, criteria for distinguishing VP from other causes of joint pain and for evaluating a suspected case of VP have not been fully established. We reviewed the literature to determine underlying mechanism, symptomology, associated pathologies, and clinical importance of VP. The formation of VP can be explained by gas solubility, pressure-volume relationships, and human physiology. CT, GRE-MRI, and multipositional views are the best imaging studies to view VP. Although most cases of VP are benign, it can be associated with clinical signs and symptoms. VP outside the spine is an underreported finding on imaging studies. VP should be on the differential diagnosis for joint pain, especially in the elderly. We have proposed criteria for diagnosing VP and generated a basic algorithm for its workup. Underreporting of this phenomenon shows a lack of awareness of VP on the part of physicians. By identifying true anatomic VP, we can prevent harm from suboptimal treatment of patients. PMID:24288359

Gohil, Ishan; Vilensky, Joel A; Weber, Edward C

2014-04-01

367

Compact vacuum insulation  

DOEpatents

Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases there between are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and various laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels. 35 figs.

Benson, D.K.; Potter, T.F.

1992-10-27

368

Compact vacuum insulation  

DOEpatents

Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases therebetween are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and variious laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels.

Benson, David K. (Golden, CO); Potter, Thomas F. (Denver, CO)

1992-01-01

369

Vacuum plasma spray coating  

NASA Technical Reports Server (NTRS)

Currently, protective plasma spray coatings are applied to space shuttle main engine turbine blades of high-performance nickel alloys by an air plasma spray process. Originally, a ceramic coating of yttria-stabilized zirconia (ZrO2.12Y2O3) was applied for thermal protection, but was removed because of severe spalling. In vacuum plasma spray coating, plasma coatings of nickel-chromium-aluminum-yttrium (NiCrAlY) are applied in a reduced atmosphere of argon/helium. These enhanced coatings showed no spalling after 40 MSFC burner rig thermal shock cycles between 927 C (1700 F) and -253 C (-423 F), while current coatings spalled during 5 to 25 test cycles. Subsequently, a process was developed for applying a durable thermal barrier coating of ZrO2.8Y2O3 to the turbine blades of first-stage high-pressure fuel turbopumps utilizing the enhanced NiCrAlY bond-coating process. NiCrAlY bond coating is applied first, with ZrO2.8Y2O3 added sequentially in increasing amounts until a thermal barrier coating is obtained. The enchanced thermal barrier coating has successfully passed 40 burner rig thermal shock cycles.

Holmes, Richard R.; Mckechnie, Timothy N.

1989-01-01

370

Precooler Ring Vacuum System  

SciTech Connect

The precooler vacuum system, as proposed by FNAL, is based on a suitable modification of the existing Electron Cooling Ring System. Because of the magnetic cycle of the bending magnets, distributed ion pumping, as exists in the Electron Cooling Ring, is not applicable. Instead, the proposed pumping will be done with commercial appendage ion pumps mounted approximately every two meters around the circumference of the ring. The loss of effective pumping speed and non-uniformity of system pressure with appendage pumps may not be major considerations but the large number required does effect experimental and analytical equipment placement considerations. There is a distributed pumping technique available which: (1) is not affected by the magnetic cycle of the bending magnets; (2) will provide a minimum of four times the hydrogen pumping speed of the proposed appendage ion pumps; (3) will require no power during pumping after the strip is activated; (4) will provide the heat source for bakeout; (5) is easily replaceable; and (6) can be purchased, installed, and operated at a generous economic advantage over the presently proposed ion pumped system. The pumping technique referred to is non-evaporable gettering with ST101 Zr/Al pumping strip. A technical description of this pumping strip is given on Data Sheet 1 and 2 attached to this report.

Moenich, J.

1980-10-02

371

NCSX Vacuum Vessel Fabrication  

SciTech Connect

The National Compact Stellarator Experiment (NCSX) is being constructed at the Princeton Plasma Physics Laboratory (PPPL) in conjunction with the Oak Ridge National Laboratory (ORNL). The goal of this experiment is to develop a device which has the steady state properties of a traditional stellarator along with the high performance characteristics of a tokamak. A key element of this device is its highly shaped Inconel 625 vacuum vessel. This paper describes the manufacturing of the vessel. The vessel is being fabricated by Major Tool and Machine, Inc. (MTM) in three identical 120º vessel segments, corresponding to the three NCSX field periods, in order to accommodate assembly of the device. The port extensions are welded on, leak checked, cut off within 1" of the vessel surface at MTM and then reattached at PPPL, to accommodate assembly of the close-fitting modular coils that surround the vessel. The 120º vessel segments are formed by welding two 60º segments together. Each 60º segment is fabricated by welding ten press-formed panels together over a collapsible welding fixture which is needed to precisely position the panels. The vessel is joined at assembly by welding via custom machined 8" (20.3 cm) wide spacer "spool pieces." The vessel must have a total leak rate less than 5 X 10-6 t-l/s, magnetic permeability less than 1.02?, and its contours must be within 0.188" (4.76 mm). It is scheduled for completion in January 2006.

Viola, M. E.; Brown, T.; Heitzenroeder, P.; Malinowski, F.; Reiersen, W.; Sutton, L.; Goranson, P.; Nelson, B.; Cole, M.; Manuel, M.; McCorkle, D.

2005-10-07

372

Vacuum energy and cosmological evolution  

E-print Network

An expanding universe is not expected to have a static vacuum energy density. The so-called cosmological constant $\\Lambda$ should be an approximation, certainly a good one for a fraction of a Hubble time, but it is most likely a temporary description of a true dynamical vacuum energy variable that is evolving from the inflationary epoch to the present day. We can compare the evolving vacuum energy with a Casimir device where the parallel plates slowly move apart ("expand"). The total vacuum energy density cannot be measured, only the effect associated to the presence of the plates, and then also their increasing separation with time. In the universe there is a nonvanishing spacetime curvature $R$ as compared to Minkowskian spacetime that is changing with the expansion. The vacuum energy density must change accordingly, and we naturally expect $\\delta\\Lambda\\sim R\\sim H^2$. A class of dynamical vacuum models that trace such rate of change can be constructed. They are compatible with the current cosmological data, and conveniently extended can account for the complete cosmic evolution from the inflationary epoch till the present days. These models are very close to the $\\Lambda$CDM model for the late universe, but very different from it at the early times. Traces of the inherent vacuum dynamics could be detectable in our recent past.

Joan Sola

2014-02-27

373

Vacuum Brazing of Accelerator Components  

NASA Astrophysics Data System (ADS)

Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.

Singh, Rajvir; Pant, K. K.; Lal, Shankar; Yadav, D. P.; Garg, S. R.; Raghuvanshi, V. K.; Mundra, G.

2012-11-01

374

Disc1 Variation Leads to Specific Alterations in Adult Neurogenesis  

PubMed Central

Disrupted in schizophrenia 1 (DISC1) is a risk factor for a spectrum of neuropsychiatric illnesses including schizophrenia, bipolar disorder, and major depressive disorder. Here we use two missense Disc1 mouse mutants, described previously with distinct behavioural phenotypes, to demonstrate that Disc1 variation exerts differing effects on the formation of newly generated neurons in the adult hippocampus. Disc1 mice carrying a homozygous Q31L mutation, and displaying depressive-like phenotypes, have fewer proliferating cells while Disc1 mice with a homozygous L100P mutation that induces schizophrenia-like phenotypes, show changes in the generation, placement and maturation of newly generated neurons in the hippocampal dentate gyrus. Our results demonstrate Disc1 allele specific effects in the adult hippocampus, and suggest that the divergence in behavioural phenotypes may in part stem from changes in specific cell populations in the brain. PMID:25272038

Chandran, Jayanth S.; Kazanis, Ilias; Clapcote, Steven J.; Ogawa, Fumiaki; Millar, J. Kirsty; Porteous, David J.; ffrench-Constant, Charles

2014-01-01

375

The Application of Fiber-Reinforced Materials in Disc Repair  

PubMed Central

The intervertebral disc degeneration and injury are the most common spinal diseases with tremendous financial and social implications. Regenerative therapies for disc repair are promising treatments. Fiber-reinforced materials (FRMs) are a kind of composites by embedding the fibers into the matrix materials. FRMs can maintain the original properties of the matrix and enhance the mechanical properties. By now, there are still some problems for disc repair such as the unsatisfied static strength and dynamic properties for disc implants. The application of FRMs may resolve these problems to some extent. In this review, six parts such as background of FRMs in tissue repair, the comparison of mechanical properties between natural disc and some typical FRMs, the repair standard and FRMs applications in disc repair, and the possible research directions for FRMs' in the future are stated. PMID:24383057

Pei, Bao-Qing; Li, Hui; Zhu, Gang; Li, De-Yu; Fan, Yu-Bo; Wu, Shu-Qin

2013-01-01

376

Local and global dynamics of warped astrophysical discs  

E-print Network

Astrophysical discs are warped whenever a misalignment is present in the system, or when a flat disc is made unstable by external forces. The evolution of the shape and mass distribution of a warped disc is driven not only by external influences but also by an internal torque, which transports angular momentum through the disc. This torque depends on internal flows driven by the oscillating pressure gradient associated with the warp, and on physical processes operating on smaller scales, which may include instability and turbulence. We introduce a local model for the detailed study of warped discs. Starting from the shearing sheet of Goldreich & Lynden-Bell, we impose the oscillating geometry of the orbital plane by means of a coordinate transformation. This warped shearing sheet (or box) is suitable for analytical and computational treatments of fluid dynamics, magnetohydrodynamics, etc., and it can be used to compute the internal torque that drives the large-scale evolution of the disc. The simplest hyd...

Ogilvie, Gordon I

2013-01-01

377

New Laser Labeling Technology for Recordable Digital Versatile Disc  

NASA Astrophysics Data System (ADS)

A new labeling technology, i.e., “LabelflashTM”, is reported. This technology uses the digital versatile disc (DVD) drive data recording head to burn high-quality images directly into a specialized dye layer on the label side of DVD discs. The basic structure of the disc is similar to a conventional double-sided recordable digital versatile disc (DVD-R). Consequently, a Labelflash disc shows various features as follows: non consumable, no special optical path or drive control system, the same working distance as that for data recording, manufactured using conventional equipment for double-sided DVD-R, fast drawing speed, high durability, and professional appearance. Moreover, four color variation types and mat-type discs were developped. The graphic quality performance index for Labelflash was newly proposed. The values were closely matched by the subjective evaluations of contrast.

Kubo, Hiroshi; Shibata, Michihiro; Yamada, Seiya; Itoga, Hisanori; Fushiki, Tatsuo

2007-06-01

378

Unilateral tilted disc and ipsilateral keratoconus in the same eye  

PubMed Central

The objective of this case was to report unilateral tilted disc in a boy with ipsilateral keratoconus. The tilted disc syndrome is a non-hereditary bilateral condition. This configuration is accompanied by situs inversus of the retinal vessels, congenital inferonasal conus, thinning of the inferonasal retinal pigment epithelium and choroid, and myopic astigmatism. Unilateral tilted disc syndrome is a rare condition. Keratoconus is a disorder characterised by progressive corneal steepening. The author present a case of unilateral tilted disc in a boy with ipsilateral keratoconus. Pterygium is a common disorder and tilted disc syndrome is a bilateral condition. But unilateral tilted disc in a boy with ipsilateral keratoconus is the first report in literature. Due to these clinical presentation, this report is an exception in literature and reported an unknown clinical coincident. PMID:22692492

Ciftci, Suleyman

2011-01-01

379

Compatible optical pickup actuator for next generation versatile disc system  

Microsoft Academic Search

Nowadays, high-density disc and high-speed optical disk drive have become popular as optical disc has many merits such as cost effectiveness, high data transfer rate, large storage capacity, removability and compatibility. In this paper, we presented a compatible optical pickup actuator for next generation versatile disc (NVD) system. This actuator has high AC sensitivities and good 2nd resonance frequency through

Lei Zhong; Jianshe Ma; Xuemin Cheng; Buqing Zhang

2008-01-01

380

Overview of disc arthroplasty—past, present and future  

Microsoft Academic Search

Degenerative disc disease is one of the most frequent spinal disorders. The anatomy and the biomechanics of the intervertebral\\u000a disc are very complex, and the pathomechanics of its degeneration are poorly understood. Despite this complexity and uncertainty,\\u000a great advances have been made in the field of disc replacement technology, with promising results. Difficulties are continuously\\u000a being encountered, but careful analysis

Tamás Fülöp Fekete; François Porchet

2010-01-01

381

Herschel DEBRIS survey of debris discs around A stars  

NASA Astrophysics Data System (ADS)

The Herschel DEBRIS survey (Disc Emission via a Bias-free Reconnaissance in the Infrared/Submillimetre) brings a unique perspective to the study of debris discs around main-sequence A-type stars. We have observed a sample of 89 A-stars with the Photodetector Array Camera and Spectrometer (PACS) on the Herschel space telescope at 100 and 160 ?m. A statistical analysis of the data shows a lower debris disc rate than has previously been found. The drop is due in part to the fact that some excess sources were resolved as background objects by the superior angular resolution (a factor of 2.5) of PACS-100 relative to that of Spitzer (MIPS-70). We found a 3-? detection rate of 23 myblue which is similar to the the detection rate around main-sequence F, G and K stars. Most of the debris discs were detected around the youngest and hottest stars in our sample. The incidence of discs in single and multiple systems was similar. The debris discs in multiple systems ware found either in tight binary systems (<1 AU) or wide ones (>100 AU). Debris discs in both tight and wide binary systems have physical properties that are statistically similar to those of discs around single stars. We did not detect any debris discs in binary systems with intermediate separation, in which the orbit and the debris disc would be on the same scale. One possible explanation is that discs in intermediate systems have evolved much faster owing to the disc-companion interactions and they are now undetectable.

Thureau, N.

2014-11-01

382

Gravitational instability in protostellar discs at low metallicities  

NASA Astrophysics Data System (ADS)

Fragmentation of protostellar discs controls the growth of protostars and plays a key role in determining the final mass of newborn stars. In this paper, we investigate the structure and gravitational stability of the protostellar discs in the full metallicity range between zero and the solar value. Using the mass-accretion rates evaluated from the thermal evolution in the preceding collapse phase of the pre-stellar cores, we calculate disc structures and their evolution in the framework of the standard steady discs. Overall, with higher metallicity, more efficient cooling results in the lower accretion rate and lower temperature inside the disc: at zero metallicity, the accretion rate is ˜10-3 M? yr-1 and the disc temperature is ˜1000 K, while at solar metallicity, ˜10-6 M? yr-1 and ˜10 K. Despite the large difference in these values, the zero- and solar-metallicity discs have similar stability properties: the Toomre parameter for the gravitational stability, which can be written using the ratio of temperatures in the disc and in the envelope as QT ˜ (Tdisc/Tenv)3/2, is ? 1, i.e. marginally stable. At intermediate metallicities of 10-5 to 10-3 Z?, however, the discs are found to be strongly unstable with QT ˜ 0.1-1 since dust cooling, which is effective only in the discs due to their high density ( ? 1010 cm- 3), makes the temperature in the discs lower than that in the envelopes. This indicates that masses of the individual stars formed as a result of the protostellar disc fragmentation can be significantly smaller than their parent core in this metallicity range. The typical stellar mass in this case would be a few M?, which is consistent with the observationally suggested mass-scale of extremely metal-poor stars.

Tanaka, Kei E. I.; Omukai, Kazuyuki

2014-04-01

383

Optic disc measurement: a comparison of indirect ophthalmoscopic methods  

Microsoft Academic Search

AIMS--Two methods of indirect ophthalmoscopic estimation of optic disc size, the 78 dioptre lens and optic disc biometer were evaluated. METHODS--Twenty nine eyes of 29 patients were measured by both methods and compared with optic disc size calculated using the three planimetric corrections described by Bengtsson and Krakau. RESULTS--The closest agreement with the clinical measurements was found using correction 3.

A F Spencer; S A Vernon

1995-01-01

384

New Brown Dwarf Discs in Upper Scorpius Observed with WISE  

NASA Technical Reports Server (NTRS)

We present a census of the disc population for UKIDSS selected brown dwarfs in the 5-10 Myr old Upper Scorpius OB association. For 116 objects originally identified in UKIDSS, the majority of them not studied in previous publications, we obtain photometry from the Wide-Field Infrared Survey Explorer data base. The resulting colour magnitude and colour colour plots clearly show two separate populations of objects, interpreted as brown dwarfs with discs (class II) and without discs (class III). We identify 27 class II brown dwarfs, 14 of them not previously known. This disc fraction (27 out of 116, or 23%) among brown dwarfs was found to be similar to results for K/M stars in Upper Scorpius, suggesting that the lifetimes of discs are independent of the mass of the central object for low-mass stars and brown dwarfs. 5 out of 27 discs (19 per cent) lack excess at 3.4 and 4.6 microns and are potential transition discs (i.e. are in transition from class II to class III). The transition disc fraction is comparable to low-mass stars.We estimate that the time-scale for a typical transition from class II to class III is less than 0.4 Myr for brown dwarfs. These results suggest that the evolution of brown dwarf discs mirrors the behaviour of discs around low-mass stars, with disc lifetimes of the order of 5 10 Myr and a disc clearing time-scale significantly shorter than 1 Myr.

Dawson, P.; Scholz, A.; Ray, T. P.; Natta, A.; Marsh, K. A.; Padgett, D.; Ressler, M. E.

2013-01-01

385

Numerical simulations of protostellar encounters I. Star-disc encounters  

E-print Network

It appears that most stars are born in clusters, and that at birth most stars have circumstellar discs which are comparable in size to the separations between the stars. Interactions between neighbouring stars and discs are therefore likely to play a key role in determining disc lifetimes, stellar masses, and the separations and eccentricities of binary orbits. Such interactions may also cause fragmentation of the discs, thereby triggering the formation of additional stars. We have carried out a series of simulations of disc-star interactions using an SPH code which treats self-gravity, hydrodynamic and viscous forces. We find that interactions between discs and stars provide a mechanism for removing energy from, or adding energy to, the orbits of the stars, and for truncating the discs. However, capture during such encounters is unlikely to be an important binary formation mechanism. A more significant consequence of such encounters is that they can trigger fragmentation of the disc, via tidally and compressionally induced gravitational instabilities, leading to the formation of additional stars. When the disc-spins and stellar orbits are randomly oriented, encounters lead to the formation of new companions to the original star in 20% of encounters. If most encounters are prograde and coplanar, as suggested by simulations of dynamically-triggered star formation, then new companions are formed in approximately 50% of encounters.

H. M. J. Boffin; S. J. Watkins; A. S. Bhattal; N. Francis; A. P. Whitworth

1998-05-28

386

On the fragmentation criteria of self-gravitating protoplanetary discs  

NASA Astrophysics Data System (ADS)

We investigate the fragmentation criterion in massive self-gravitating discs. We present new analysis of the fragmentation conditions which we test by carrying out global three-dimensional numerical simulations. Whilst previous work has placed emphasis on the cooling time-scale in units of the orbital time-scale, ?, we find that at a given radius the surface mass density (i.e. disc mass and profile) and star mass also play a crucial role in determining whether a disc fragments or not as well as where in the disc fragments form. We find that for shallow surface mass density profiles (p < 2, where ??R-p), fragments form in the outer regions of the disc. However for steep surface mass density profiles (p > rsim 2), fragments form in the inner regions of a disc. In addition, we also find that the critical value of the cooling time-scale in units of the orbital time-scale, ?crit, found in previous simulations is only applicable to certain disc surface mass density profiles and for particular disc radii and is not a general rule for all discs. We find an empirical fragmentation criterion between the cooling time-scale in units of the orbital time-scale, ?, the surface mass density, the star mass and the radius.

Meru, Farzana; Bate, Matthew R.

2011-01-01

387

Stacked-disc structure for fluid filter or valve silencer  

NASA Technical Reports Server (NTRS)

A stacked-disc structure is comprised of a stack of annular discs (13) scalloped along the outer edge to provide lobes (13a) and etched on one side to provide lands (13a). A web (13d) is retained in the lobes to strengthen the discs so that they will not collapse due to high fluid pressure. The stack of discs is retained by a housing (10) having a fluted interior wall to retain the ends of the lobes. End plates (11 and 12) secure the stack of discs with a spacer (14) at one end having lands (14a) on lobes which match the lobes of the stacked discs to allow fluid to flow into, or out of, the spaces between the lobes of the stacked discs. The spaces between the lands on the etched discs provide passages for fluid flow into or out of the hollow core of the stack. The height of the lands (i.e., depth of the etch) determines the size of the smallest particle that will be permitted to flow through. The stacked-disc structure may be connected to the inlet of a valve, or be incorporated into the valve housing on the inlet side of the valve seat to assure substantially constant fluid velocity, and thereby reduce valve noise when the valve is operated.

Hagler, Jr., Ray (Inventor)

1983-01-01

388

MECHANICAL DESIGN CRITERIA FOR INTERVERTEBRAL DISC TISSUE ENGINEERING  

PubMed Central

Due to the inability of current clinical practices to restore function to degenerated intervertebral discs, the arena of disc tissue engineering has received substantial attention in recent years. Despite tremendous growth and progress in this field, translation to clinical implementation has been hindered by a lack of well-defined functional benchmarks. Because successful replacement of the disc is contingent upon replication of some or all of its complex mechanical behaviour, it is critically important that disc mechanics be well characterized in order to establish discrete functional goals for tissue engineering. In this review, the key functional signatures of the intervertebral disc are discussed and used to propose a series of native tissue benchmarks to guide the development of engineered replacement tissues. These benchmarks include measures of mechanical function under tensile, compressive and shear deformations for the disc and its substructures. In some cases, important functional measures are identified that have yet to be measured in the native tissue. Ultimately, native tissue benchmark values are compared to measurements that have been made on engineered disc tissues, identifying measures where functional equivalence was achieved, and others where there remain opportunities for advancement. Several excellent reviews exist regarding disc composition and structure, as well as recent tissue engineering strategies; therefore this review will remain focused on the functional aspects of disc tissue engineering. PMID:20080239

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

2009-01-01

389

Laparoscopic management of a small bowel herniation from an ileal conduit: report of a case and review of the literature.  

PubMed

Bladder carcinoma can be treated with cystectomy and urinary diversion. Ileal conduit is a popular technique, originally performed with closure of all mesenteric and peritoneal defects to minimize internal herniation. Recent advances in laparoscopic and robotic techniques often leave these defects open. We present a case of a 75-year-old gentleman with a small bowel entrapment underneath an intraperitoneal ileal conduit and ureter causing obstruction. This internal hernia occurred 2 months after undergoing a DaVinci robotic-assisted laparoscopic cystoprostatectomy with an ileal conduit. Bowel obstruction is an important complication associated with the need for reoperation and patient mortality. Historical review shows a precedent for closure of the mesenteric defect, obliterating the peritoneal defect in the right lumbar gutter, and suturing the ileal conduit to the posterior peritoneum to prevent potential internal hernias. The literature involving ileal conduits is examined for consensus on the preferred method of treating these potential spaces. PMID:23579536

Coughlin, Lisa M; Orr, Dennis P

2013-04-01

390

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

SciTech Connect

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

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

1988-11-01

391

Assessing the Effect of Spaceflight on the Propensity for Astronauts to Develop Disk Herniation  

NASA Technical Reports Server (NTRS)

BACKGROUND: A previous study [1] reported that the instantaneous risk of developing a Herniated Nucleus Pulposus (HNP) was higher in astronauts who had flown at least one mission, as compared with those in the corps who had not yet flown. However, the study only analyzed time to HNP after the first mission (if any) and did not account for the possible effects of multiple missions. While many HNP's occurred well into astronauts' careers or in some cases years after retirement, the higher incidence of HNPs relatively soon after completion of space missions appears to indicate that spaceflight may lead to an increased risk of HNP. The purpose of this study was to support the Human System Risk Board assessment of back pain, evaluate the risk of injury due to dynamic loads, and update the previous dataset which contained events up to December 31, 2006. METHODS: Data was queried from the electronic medical record and provided by the Lifetime Surveillance of Astronaut Health. The data included all 330 United States astronauts from 1959 through February 2014. Cases were confirmed by Magnetic Resonance Imaging, Computerized Tomography, Myelography, operative findings, or through clinical confirmation with a neurologist or neurosurgeon. In this analysis, astronauts who had an HNP at selection into the corps or had an HNP diagnosis prior to their first flight were excluded. The statistical challenges in using the available data to separate effects of spaceflight from those associated with general astronaut training and lifestyle on propensity to develop HNPs are many. The primary outcome is reported date of first HNP (if any), which at best is only an approximation to the actual time of occurrence. To properly analyze this data with a survival analysis model, one must also know the "exposure" time - i.e. how long each astronaut has been at risk for developing an HNP. If an HNP is reported soon after a mission, is it mission caused or general? If the former, exposure time should be counted from the time of landing (assuming the risk of HNP occurring during a mission is zero). If the latter, exposure time should be counted from the time of selection; however we can't directly know which one to use. In our analysis we take both of these possibilities into account with a competing risks model, wherein two distinct stochastic processes are going on: TG = time to HNP (general) and TS = time to HNP (spaceflight). Under this type of model, whichever of these occurs first is what we observe; in other words we don't observe TG or TS, only min(TG, TS). Here, we parameterized the model in terms of separate Weibull hazard functions for each process and estimated all parameters using maximum likelihood. In addition, we allowed for a "cured fraction" - i.e. the possibility that some astronauts may never develop an HNP. RESULTS: Results will include a depiction of the competing hazard functions as well as a probability curve for the relative likelihood that an HNP reported at a given time after a mission is actually mission caused. Other factors, such as dwell time in microgravity and vehicle landing environment will be explored. An overall assessment as to whether spaceflight truly exacerbates HNP risk will be made.

Feiveson, A. H.; Mendez, C. M.; Somers, J. T.

2014-01-01

392

Does disk space degeneration according to Los Angeles and Modic scales have relation with recurrent disk herniation?  

PubMed Central

Background: After single disk herniation operation, about 5–20% recurrences may occur. Different etiology may affect the prevalence of recurrence. Disk degeneration according to Modic and Los Angles scales could affect recurrence rate. This study wants to show the relationship between disk space degeneration according to these scales on severity, time, and prevalence of disk herniation recurrence. Materials and Methods: Thirty-four patients presented with radicular pain (with or without back pain) and history of lumbar disk surgery was included in this prospective study. Pre- and postoperative T2-weighted sagittal magnetic resonance imaging (MRI) compared for Modic and Los Angeles disk degeneration grading, then, data analysis on SPSS (version 20) software, paired t-test, and others. Results: The result of study shows for first operation that grade (II) Los Angeles is the most common, but, for second procedure grade (IV) was less common and the mostly decreased (from 14.7 to 9.2%). In addition, Wilcoxon test shows no change of Los Angeles grading for both first and second surgery (P = 0.06). Whereas; based on Modic criteria grading was different from first operation, in other words, grade (I) (41.2%) in first operation was changed to 20.6% in second operation (P = 0.007). Conclusion: Our study showed that the Los Angeles criterion is more practical and useful for prediction of recurrence and in the patients with Los Angles grade III and IV and grade II and III on Modic scale, the chance of recurrence is less than patients with lower grades.

Abrishamkar, Saied; Mahmoudkhani, Mehdi; Aminmansour, Bahram; Mahabadi, Amir; Jafari, Shohreh

2014-01-01

393

Einstein-?tsuki vacuum equations  

NASA Astrophysics Data System (ADS)

The generalisation of the Einstein vacuum theory to ?tsuki geometry is considered. It is shown that the theory based on Lagrangian density ?-gR is consistent and leads to a theory that is classically indistinguishable from the Einstein theory.

Smrz, P. K.

1993-01-01

394

Inhomogeneous and Interacting Vacuum Energy  

NASA Astrophysics Data System (ADS)

Vacuum energy is a simple model for dark energy driving an accelerated expansion of the universe. If the vacuum energy is inhomogeneous in spacetime then it must be interacting. We present the general equations for a spacetime-dependent vacuum energy in cosmology, including inhomogeneous perturbations. We show how any dark energy cosmology can be described by an interacting vacuum+matter. Different models for the interaction can lead to different behaviour (e.g., sound speed for dark energy perturbations) and hence could be distinguished by cosmological observations. As an example we present the cosmic microwave microwave background anisotropies and the matter power spectrum for two different versions of a generalised Chaplygin gas cosmology.

De-Santiago, Josue; Wands, David; Wang, Yuting

395

Vacuum lamination of photovoltaic modules  

NASA Technical Reports Server (NTRS)

Vacuum lamination of terrestrial photovoltaic modules is a new high volume process requiring new equipment and newly develop materials. Equipment development, materials research, and some research in related fields and testing methods are discussed.

Burger, D. R.

1982-01-01

396

Vacuum system pump down analysis  

SciTech Connect

My assignment on the SP-100 Vacuum Vessel Vacuum System Team was to perform a transient pump down analysis for the vacuum vessel that will house the SP-100 reactor during testing. Pump down time was calculated for air and helium. For all cases the proposed vacuum system will be able to pump down the vessel within the required time. The use of a larger rotary piston pump (DUO250) improves the pump down time by 35 minutes and therefore should be considered. The 6-inch duct for the roughing line is optimal, however, because all cases are well below the 24 hour time frame, the 4-inch duct is sufficient. The use of the single turbomolecular pump during pump down is sufficient. A pump down with helium in the vessel and a helium inleakage delays the time to achieve the base pressure marginally and is acceptable.

Rohrdanz, D.R.

1990-08-01

397

Radiation of Accretion Discs in Strong Gravity  

E-print Network

In this thesis a computational tool for modelling spectral features of X-ray sources in a strong gravitational field is developed. Six transfer functions, the gravitational and Doppler shift, lensing, emission angle, relative time delay, change of the polarization angle and azimuthal emission angle, have been computed for light rays emitted from the equatorial plane of the Kerr black hole and received by an observer at infinity. The values of these functions for different angular momenta of the black hole and inclination angles of the observer in Kerr ingoing coordinates have been stored in the form of tables in a FITS file. Graphical representations of the results are shown as an atlas of contour figures of these functions. For the modelling of the spectra of an accretion disc, several general relativistic codes have been developed. Some of them can be used inside a more general spectral fitting package XSPEC for routine fitting of the data measured by X-ray satellites. These are the models for the relativistic emission lines, Compton reflection and for the general use as a relativistic extension of existing models (convolution models). Other components of the tool have extended features for studying non-stationary emission from accretion discs and polarimetry. The newly developed codes have been employed in several applications: data from XMM-Newton observations of Seyfert galaxy MCG-6-30-15 have been fitted, emission from an X-ray illuminated spot orbiting near a black hole was simulated, and polarization from an accretion disc illuminated by a primary source located above the black hole was computed.

Michal Dovciak

2004-11-22

398

Vacuum Variable Medium Temperature Blackbody  

Microsoft Academic Search

This article describes the vacuum variable medium-temperature blackbody (VMTBB) constructed to serve as a highly stable reference\\u000a source with an aperture diameter of 20 mm in the temperature range from 150 °C to 430 °C under medium-vacuum conditions (10?3 Pa) and in a reduced background environment (liquid-nitrogen-cooled shroud). The VMTBB was realized for the calibration facility\\u000a at the PTB in the field of

S. P. Morozova; N. A. Parfentiev; B. E. Lisiansky; U. A. Melenevsky; B. Gutschwager; C. Monte; J. Hollandt

2010-01-01

399

26 CFR 1.6011-2 - Returns, etc., of DISC's and former DISC's.  

Code of Federal Regulations, 2010 CFR

...must furnish to each of its shareholders on or before the last...distributions from the DISC to such shareholder for the taxable year of...designated in the form of a communication sent to a shareholder and service center at...

2010-04-01

400

Subretinal and disc neovascularisation in serpiginous choroiditis.  

PubMed Central

Three out of 15 patients with serpiginous choroiditis who have been followed up for 1 to 10 years (mean 4.9 years) developed subretinal neovascularisation in the macula. In one eye new vessels were treated with argon laser without attaining permanent obliteration, in the second eye the neovascular membrane was regarded as untreatable because it was under the fovea, and in the third eye new vessels became obliterated spontaneously after atrophy of the surrounding choriocapillaris and the pigment epithelium of the retina. In a furth patient disc new vessels were seen at the active stage of serpiginous choroiditis; these new vessels disappeared after scarring of the initial chorioretinal lesions. Images PMID:6176258

Laatikainen, L; Erkkilä, H

1982-01-01

401

An Analysis of Burst Disc Pressure Instability  

SciTech Connect

During the development stage of the 1X Acorn burst disc, burst pressure test results exhibited an unexpected increase of 8 to 14% over times of 90--100 days from initial fabrication. This increase is a concern where design constraints require stability. The disc material, 316L stainless steel sheet, is formed to a dome-like geometry and scored to produce a thin-walled, high-strength ligament. The fracture events controlling burst occur in that ligament. Thus it has been characterized both for tensile properties and microstructure through nanoindentation, magnetic measurements, optical and transmission electron microscopy. These results compare favorably with finite element simulation of the properties of the ligament. The ligament exhibits a highly heterogeneous microstructure; its small volume and microstructural heterogeneity make it difficult to identify which microstructural feature controls fracture and hence burst pressure. Bulk mechanical test specimens were fabricated to emulate mid-ligament properties, and aged at both room and elevated temperatures to characterize and accelerate the temporal behavior of the burst disc. Property changes included yield and ultimate tensile strength increases, and fracture strain decreases with aging. Specimens were subjected to a reversion anneal identical to that given the burst disc to eliminate the martensite phase formed during rolling. Reversion-annealed samples exhibited no change in properties in room temperature or accelerated aging, showing that the reversion-anneal eliminated the aging phenomenon. Aging was analyzed in terms of diffusion controlled precipitate growth kinetics, showing that carbon migration to dislocations is consistent with the strength increases. A vacancy-assisted diffusion mechanism for carbon transport is proposed, giving rise to rapid aging, which replaces interstitial carbon diffusion until excess vacancies from deformation are consumed. Mechanical activation parameters in stress relaxation were measured, indicating that the deformation structures formed at high strains typical of the score ligament are resistant to annealing, and mimic the behavior of a thermal obstacles. This model also qualitatively explains the different rates of aging resulting from a range of levels of cold work.

S. L. Robinson; B. C. Odegard, Jr.; N. r. Moody; S. H. Goods

2000-06-01

402

ISASS Policy Statement – Cervical Artificial Disc  

PubMed Central

Morgan Lorio, MD, FACS, Chair, ISASS Task Force on Coding & Reimbursement The ISASS Task Force reached out to Domagoj Coric, MD to provide a timely summation on cervical disc arthroplasty given his special interest and recent IASP championship of this innovative technology to insure enhanced spine patient access. The ISASS Task Force is pleased with this step towards published ISASS societal policy and applauds Dr. Coric's effort; if ISASS is to continue to succeed we must continually harness the voluntary talents and energies of our members with gratitude.

2014-01-01

403

Vacuum Refining of Molten Silicon  

NASA Astrophysics Data System (ADS)

Metallurgical fundamentals for vacuum refining of molten silicon and the behavior of different impurities in this process are studied. A novel mass transfer model for the removal of volatile impurities from silicon in vacuum induction refining is developed. The boundary conditions for vacuum refining system—the equilibrium partial pressures of the dissolved elements and their actual partial pressures under vacuum—are determined through thermodynamic and kinetic approaches. It is indicated that the vacuum removal kinetics of the impurities is different, and it is controlled by one, two, or all the three subsequent reaction mechanisms—mass transfer in a melt boundary layer, chemical evaporation on the melt surface, and mass transfer in the gas phase. Vacuum refining experimental results of this study and literature data are used to study the model validation. The model provides reliable results and shows correlation with the experimental data for many volatile elements. Kinetics of phosphorus removal, which is an important impurity in the production of solar grade silicon, is properly predicted by the model, and it is observed that phosphorus elimination from silicon is significantly increased with increasing process temperature.

Safarian, Jafar; Tangstad, Merete

2012-12-01

404

Simulations of spectral lines from an eccentric precessing accretion disc  

E-print Network

Two dimensional SPH simulations of a precessing accretion disc in a q=0.1 binary system (such as XTE J1118+480) reveal complex and continuously varying shape, kinematics, and dissipation. The stream-disc impact region and disc spiral density waves are prominent sources of energy dissipation.The dissipated energy is modulated on the period P_{sh} = ({P_{orb}}^{-1}-{P_{prec}}^{-1}^{-1} with which the orientation of the disc relative to the mass donor repeats. This superhump modulation in dissipation energy has a variation in amplitude of ~10% relative to the total dissipation energy and evolves, repeating exactly only after a full disc precession cycle. A sharp component in the light curve is associated with centrifugally expelled material falling back and impacting the disc. Synthetic trailed spectrograms reveal two distinct "S-wave" features, produced respectively by the stream gas and the disc gas at the stream-disc impact shock. These S-waves are non-sinusoidal, and evolve with disc precession phase. We identify the spiral density wave emission in the trailed spectrogram. Instantaneous Doppler maps show how the stream impact moves in velocity space during an orbit. In our maximum entropy Doppler tomogram the stream impact region emission is distorted, and the spiral density wave emission is uppressed. A significant radial velocity modulation of the whole line profile occurs on the disc precession period. We compare our SPH simulation with a simple 3D model: the former is appropriate for comparison with emission lines while the latter is preferable for skewed absorption lines from precessing discs.

S. B. Foulkes; C. A. Haswell; J. R. Murray; D. J. Rolfe

2004-01-19

405

Safety and Efficacy of Dietary Agmatine Sulfate in Lumbar Disc-associated Radiculopathy. An Open-label, Dose-escalating Study Followed by a Randomized, Double-blind, Placebo-controlled Trial.  

PubMed

Objective. Agmatine, decarboxylated arginine, was shown in preclinical studies to exert efficacious neuroprotection by interacting with multiple molecular targets. This study was designed to ascertain safety and efficacy of dietary agmatine sulfate in herniated lumbar disc-associated radiculopathy. Study Design. First, an open-label dose escalation study was performed to assess the safety and side-effects of agmatine sulfate. In the follow-up study, participants diagnosed with herniated lumbar disc-associated radiculopathy were randomly assigned to receive either placebo or agmatine sulfate in a double-blind fashion. Methods. Participants in the first study were recruited consecutively into four cohorts who took the following escalating regimens: 1.335 g/day agmatine sulfate for 10 days, 2.670 g/day for 10 days, 3.560 g/day for 10 days, and 3.560 g/day for 21 days. Participants in the follow-up study were assigned to receive either placebo or agmatine sulfate, 2.670 g/day for 14 days. Primary outcome measures were pain using the visual analog scale, the McGill pain questionnaire and the Oswestry disability index, sensorimotor deficits, and health-related quality of life using the 36-item short form (SF-36) questionnaire. Secondary outcomes included other treatment options, and safety and tolerability assessment. Results. Safety parameters were within normal values in all participants of the first study. Three participants in the highest dose cohort had mild-to-moderate diarrhea and mild nausea during treatment, which disappeared upon treatment cessation. No other events were observed. In the follow-up study, 51 participants were randomly enrolled in the agmatine group and 48 in the placebo. Continuous improvement of symptoms occurred in both groups, but was more pronounced in the agmatine (analyzed n = 31) as compared with the placebo group (n = 30). Expressed as percent of baseline values, significantly enhanced improvement in average pain measures and in quality of life scores occurred after treatment in the agmatine group (26.7% and 70.8%, respectively) as compared with placebo (6.0% [P disc-associated radiculopathy. Study Registration. ClinicalTrials.gov Protocol Registration System Identifier: NCT00405041. PMID:20447305

Keynan, Ory; Mirovsky, Yigal; Dekel, Samuel; Gilad, Varda H; Gilad, Gad M

2010-03-01

406

The jet-disc connection in AGN  

NASA Astrophysics Data System (ADS)

We present our latest results on the connection between accretion rate and relativistic jet power in active galactic nuclei (AGN), by using a large sample which includes mostly blazars, but contains also some radio galaxies. The jet power can be traced by ?-ray luminosity in the case of blazars, and radio luminosity for both classes. The accretion-disc luminosity is instead traced by the broad emission lines. Among blazars, we find a correlation between broad line emission and the ?-ray or radio luminosities, suggesting a direct tight connection between jet power and accretion rate. We confirm that the observational differences between blazar subclasses reflect differences in the accretion regime, but with blazars only we cannot properly access the low-accretion regime. By introducing radio galaxies, we succeed in observing the fingerprint of the transition between radiatively efficient and inefficient accretion discs in the jetted AGN family. The transition occurs at the standard critical value Ld/LEdd ˜ 10-2 and it appears smooth. Below this value, the ionizing luminosity emitted by the accretion structure drops significantly.

Sbarrato, T.; Padovani, P.; Ghisellini, G.

2014-11-01

407

Central flow tilting disc valve for aortic valve replacement  

PubMed Central

A new central flow tilting disc valve has been introduced. The clinical experience from the first 50 patients treated with aortic valve replacement and followed up for 12 months is reported. The results obtained are so encouraging that the tilting disc valve is at present preferred for all aortic valve replacements in this institution. Images PMID:5485003

Björk, Viking Olov

1970-01-01

408

James Clerk Maxwell and the dynamics of astrophysical discs  

Microsoft Academic Search

Maxwell's investigations into the stability of Saturn's rings provide one of the earliest analyses of the dynamics of astrophysical discs. Current research in planetary rings extends Maxwell's kinetic theory to treat dense granular gases of particles undergoing moderately frequent inelastic collisions. Rather than disrupting the rings, local instabilities may be responsible for generating their irregular radial structure. Accretion discs around

Gordon I. Ogilvie

2008-01-01

409

Optimization of Valve Disc Using Orthogonal Array and Kriging Model  

NASA Astrophysics Data System (ADS)

A butterfly valve is a type of flow control device, typically used to regulate a fluid flowing. Currently, FEA is often used to predict the safety in the design of valve disc. Also, the study about the affection of butterfly valve's disc to the valve flow characteristics by using CFD has been done by many researchers. Along with the development of computer technique, design and analysis of computer experiments has becoming more and more important in engineering design and optimization. Hereinto Kriging model is one popular analysis approach for the purpose of creating a cheap "meta-model" as a surrogate to a computationally expensive simulation model. In this paper, the numerical analysis considered the strength, pressure loss coefficient and weight of valve disc simultaneously is investigated to improve the shape of a traditional butterfly valve disc. Firstly, an initial model of butterfly valve is made to evaluate the performance of the valve disc by using CFD and FEM. Then several experiments with different variables combination of the valve disc are conducted by mean of orthogonal array. Finally, the Kriging model is used to find the optimum variables combination of valve disc based on the result of computer experiments. In addition, the optimum result is verified by FEA and CFD simulation again. The result shows that compared with traditional computer experiments, optimization by using Kriging model can improve the weight of the valve disc very effectively in a short time.

Song, Xueguan; Wang, Lin; Kang, Jungho; Kim, Seung Gyu; Jo, Young Jik; Park, Youngchul

2008-10-01

410

Rayleigh disc measurements in superfluid 4He and 3He  

NASA Astrophysics Data System (ADS)

The Rayleigh disc as a detector of hydrodynamic flow in superfluids is described. An experimental cell incorporating a novel system for detecting the deflection of the disc - the Butterfly-valve inductor (1) - has been used to observe for the first time steady thermal counterflow in superfluid 4He. We describe the extension of these experiments to superfluid 3He.

Newbury, R.; Hutchins, J. D.; Betts, D. S.; Brewer, D. F.; Garrett, S.; Truscott, W. S.

1981-08-01

411

DISC1 Ser704Cys impacts thalamic-prefrontal connectivity.  

PubMed

The Disrupted-in-Schizophrenia 1 (DISC1) gene has been thought as a putative susceptibility gene for various psychiatric disorders, and DISC1 Ser704Cys is associated with variations of brain morphology and function. Moreover, our recent diffusion magnetic resonance imaging (dMRI) study reported that DISC1 Ser704Cys was associated with information transfer efficiency in the brain anatomical network. However, the effects of the DISC1 gene on functional brain connectivity and networks, especially for thalamic-prefrontal circuit, which are disrupted in various psychiatric disorders, are largely unknown. Using a functional connectivity density (FCD) mapping method based on functional magnetic resonance imaging data in a large sample of healthy Han Chinese subjects, we first investigated the association between DISC1 Ser704Cys and short- and long-range FCD hubs. Compared with Ser homozygotes, Cys-allele individuals had increased long-range FCD hubs in the bilateral thalami. The functional and anatomical connectivity of the thalamus to the prefrontal cortex was further analyzed. Significantly increased thalamic-prefrontal functional connectivity and decreased thalamic-prefrontal anatomical connectivity were found in DISC1 Cys-allele carriers. Our findings provide consistent evidence that the DISC1 Ser704Cys polymorphism influences the thalamic-prefrontal circuits in humans and may provide new insights into the neural mechanisms that link DISC1 and the risk for psychiatric disorders. PMID:24146131

Liu, Bing; Fan, Lingzhong; Cui, Yue; Zhang, Xiaolong; Hou, Bing; Li, Yonghui; Qin, Wen; Wang, Dawei; Yu, Chunshui; Jiang, Tianzi

2015-01-01

412

Revolution Now? Classical Music Recordings and Compact Discs.  

ERIC Educational Resources Information Center

Discusses the change of library music collections from long-playing (LP) recordings to compact discs (CD). Highlights include the drawbacks of LPs, disc prices and players, sound quality, logistics, selection of recordings, and a renewed commitment to sound recording facilities and collections. Ten sources are given. (EJS)

Curtis, Robert

1986-01-01

413

Tribological properties of automotive disc brakes with solid lubricants  

Microsoft Academic Search

In automotive brake systems, high temperatures and pressures are generated at the contacting surfaces. This affects the pad and disc materials, creating a friction film between the surfaces, which consists of wear particles and volatile reactants from the pad and disc. To acquire suitable tribological properties, a pad matrix contains up to 20 different ingredients, mainly selected from experience. In

Luise Gudmand-Høyer; Allan Bach; Georg T Nielsen; Per Morgen

1999-01-01

414

On the evolution of the Snow Line in Protoplanetary Discs  

NASA Astrophysics Data System (ADS)

We examine the evolution of the snow line in a protoplanetary disc. If the magneto-rotational instability (MRI) drives turbulence throughout the disc, there is a unique snow line outside of which the disc is icy. The snow line moves closer to the star as the infall accretion rate drops. Because the snow line moves inside the radius of the Earth's orbit, the formation of our water-devoid planet is difficult with this model. However, protoplanetary discs are not likely to be sufficiently ionised to be fully turbulent. A dead zone at the mid-plane slows the flow of material through the disc and a global steady state cannot be achieved. We model the evolution of the snow line also in a disc with a dead zone. As the mass is accumulating, the outer parts of the dead zone become self gravitating, heat the massive disc and thus the outer snow line does not come inside the radius of the Earth's orbit. With this model there is sufficient time and mass in the disc for the Earth to form from water-devoid planetesimals at a radius of 1AU. Furthermore, the additional inner icy region within the dead zone predicted by this model may allow for the formation of giant planets close to their host star without the need for much migration.

Martin, Rebecca G.; Livio, Mario

2014-01-01

415

Spine imaging after lumbar disc replacement: pitfalls and current recommendations  

Microsoft Academic Search

BACKGROUND: Most lumbar artificial discs are still composed of stainless steel alloys, which prevents adequate postoperative diagnostic imaging of the operated region when using magnetic resonance imaging (MRI). Thus patients with postoperative radicular symptoms or claudication after stainless steel implants often require alternative diagnostic procedures. METHODS: Possible complications of lumbar total disc replacement (TDR) are reviewed from the available literature

Yohan Robinson; Bengt Sandén

2009-01-01

416

Type II Migration: Varying Planet Mass and Disc Viscosity  

E-print Network

This paper continues an earlier study of giant planet migration, examining the effect of planet mass and disc viscosity on the migration rate. We find that the migration rate of a gap-opening planet varies systematically with the planet's mass, as predicted in our earlier work. However, the variation with disc viscosity appears to be much weaker than expected.

Richard G. Edgar

2008-07-03

417

Phase Change Disc for High Data Rate Recording  

Microsoft Academic Search

We have developed a phase change disc having a thin transparent cover layer corresponding to the new optical recording system (DVR) using a blue laser (405 nm) and a numerical aperture (NA) of 0.85. We have achieved a user capacity of 22 GB per side of the 120 mm diameter disc, and a user data recording rate of 70 Mbps

Hiroyasu Inoue; Hideki Hirata; Tatsuya Kato; Hiroshi Shingai; Hajime Utsunomiya

2001-01-01

418

Multi-hundred horsepower permanent magnet brushless disc motors  

Microsoft Academic Search

Permanent magnet motors are now practical up to thousands of horsepower. The relative advantages of disc, rotating cylinder, and cup rotor geometries are dependent on shaft speed and power level. Brushless disc motors with pulse width modulated drives have been demonstrated over a range of 200 to 20000 RPM and 10 to 700 horsepower

Alan R. Millner; Kaman Electromagnetics Corp

1994-01-01

419

Gene terapy in regeneration of the intervertebral disc  

Microsoft Academic Search

Background to regeneration of the intervertebral disc: Our research is directed towards exploring the importance of the extracellular environment on the function of cells from the central nucleus pulposus (NP) of the intervertebral disc (IVD) and utilizing that information to facilitate strategies for regenerating the degenerate IVD. The NP is a key component of the IVD. The matrix produced by

Tony Freemont; Stephen Richardson; Christine LeMaitre; Judith Hoyland

420

Disc-O-Logue: French Language Popular Recording Catalog  

NSDL National Science Digital Library

Can't remember who sang "La Machine a Laver"? Disc-O-Logue, the catalogue that lists French-language popular music recordings available in Canada, has the answer for you. Disc-O-Logue, a music publication created by Louise Lamothe, lists French language songs from Canada, France, and other parts of the French-speaking world that were available on LP and 45-rpm discs in Canada from 1962-1979. The National Library of Canada acquired the Disc-O-Logue archive in 1986 and has converted part of it, information on 90,000 songs, into a database which can be searched by song title, performer, composer, format, and label. In addition, the site features a gallery of album cover artwork, examples of best seller lists from 1963 to 1966, and a description of Madame Lamothe's process of creating Disc-O-Logue.

421

Stress and Dynamic Analysis of Rotating Composite Disc  

NASA Astrophysics Data System (ADS)

The present paper focuses on the dynamic behaviour and stresses in a fiber reinforced composite disc for possible applications to turbomachines. The discs of rotors in turbomachines, in addition to centrifugal loading, are also subjected to flexural vibrations. Variation of bending natural frequencies of composite disc in different modes, with several numbers of nodal diameters and nodal circles, is studied with respect to rotational speed and the various fibre reinforcement configurations. Natural frequencies associated with forward and backward travelling waves are obtained, which give the critical speed(s) of the disc. The semipolar configuration is studied in detail, in which the effect of the inclination of the reinforcement with the radial direction, on the dynamic characteristics of the disc is examined.

Dev, Rahul; Gupta, K.; Singh, S. P.

422

Bending instability in galactic discs: advocacy of the linear theory  

NASA Astrophysics Data System (ADS)

We demonstrate that in N-body simulations of isolated disc galaxies, there is numerical vertical heating which slowly increases the vertical velocity dispersion and the disc thickness. Even for models with over a million particles in a disc, this heating can be significant. Such an effect is just the same as in numerical experiments by Sellwood. We also show that in a stellar disc, outside a boxy/peanut bulge, if it presents, the saturation level of the bending instability is rather close to the value predicted by the linear theory. We pay attention to the fact that the bending instability develops and decays very fast, so it cannot play any role in secular vertical heating. However, the bending instability defines the minimal value of the ratio between the vertical and radial velocity dispersions ?z/?R ? 0.3 (so indirectly the minimal thickness), which stellar discs in real galaxies may have. We demonstrate that observations confirm the last statement.

Rodionov, S. A.; Sotnikova, N. Ya.

2013-09-01

423

Measurement of partial pressures in vacuum technology and vacuum physics  

NASA Technical Reports Server (NTRS)

It is pointed out that the measurement of gaseous pressures of less than 0.0001 torr is based on the ionization of gas atoms and molecules due to collisions with electrons. The particle density is determined in place of the pressure. The ionization cross sections for molecules of various gases are discussed. It is found that the true pressure in a vacuum system cannot be determined with certainty if it is unknown which gas is present. Effects of partial pressure determination on the condition of the vacuum system are discussed together with ion sources, systems of separation, and ion detection.

Huber, W. K.

1986-01-01

424

[Acute abdomen in children: a continuous challenge. Two cases report: Meckel's diverticulum with small bowel volvolus and internal herniation related to epiploic appendagitis mimicking acute appendicitis].  

PubMed

Acute abdomen is a continuous clinical challenge in pediatric age. The aim of our study is to describe two pediatric rare cases: the first case is a small bowel volvolus related to Meckel's diverticulum confused with an intestinal intussusception; the second an internal herniation related to epiploic appendagitis with intestinal obstruction mimic acute appendicitis in two years old children. We review the current literature. PMID:25004643

Gasparella, M; Ferro, M; Marzaro, M; Benetton, C; Zanatta, C; Zoppellaro, F; Gasparella, M

2014-01-01

425

Vacuum as a hyperbolic metamaterial  

E-print Network

As demonstrated by Chernodub, vacuum in a strong magnetic field behaves as a periodic Abrikosov vortex lattice in a type-II superconductor. We investigate electromagnetic behavior of vacuum in this state. Since superconductivity is realized along the axis of magnetic field only, strong anisotropy of the vacuum dielectric tensor is observed. The diagonal components of the tensor are positive in the x and y directions perpendicular to the magnetic field, and negative in the z direction along the field. As a result, vacuum behaves as a hyperbolic metamaterial medium. If the magnetic field is constant, low frequency extraordinary photons experience this medium as a (3+1) Minkowski spacetime in which the role of time is played by the spatial z coordinate. Spatial variations of the magnetic field curve this effective spacetime, and may lead to formation of "event horizons", which are analogous to electromagnetic black holes in hyperbolic metamaterials. We also note that hyperbolic metamaterials behave as diffractionless "perfect lenses". Since large enough magnetic fields probably had arisen in the course of evolution of early Universe, the demonstrated hyperbolic behavior of early vacuum may have imprints in the large scale structure of the present-day Universe.

Igor I. Smolyaninov

2011-08-10

426

The Light-Front Vacuum  

E-print Network

Background: The vacuum in the light-front representation of quantum field theory is trivial while vacuum in the equivalent canonical representation of the same theory is non-trivial. Purpose: Understand the relation between the vacuum in light-front and canonical representations of quantum field theory and the role of zero-modes in this relation. Method: Vacuua are defined as linear functionals on an algebra of field operators. The role of the algebra in the definition of the vacuum is exploited to understand this relation. Results: The vacuum functional can be extended from the light-front Fock algebra to an algebra of local observables. The extension to the algebra of local observables is responsible for the inequivalence. The extension defines a unitary mapping between the physical representation of the local algebra and a sub-algebra of the light-front Fock algebra. Conclusion: There is a unitary mapping from the physical representation of the algebra of local observables to a sub-algebra of the light-fro...

Herrmann, Marc

2015-01-01

427

Measurement of Local Strains in Intervertebral Disc Anulus Fibrosus Tissue under Dynamic Shear: Contributions of Matrix Fiber Orientation and Elastin Content  

PubMed Central

Shear strain has been implicated as an initiator of intervertebral disc anulus failure, however a clear, multi-scale picture of how shear strain affects the tissue microstructure has been lacking. The purposes of this study were to measure microscale deformations in anulus tissue under dynamic shear in two orientations, and to determine the role of elastin in regulating these deformations. Bovine AF tissue was simultaneously shear loaded and imaged using confocal microscopy following either a buffer or elastase treatment. Digital image analysis was used to track through time local shear strains in specimens sheared transversely, and stretch and rotation of collagen fiber bundles in specimens sheared circumferentially. The results of this study suggest that sliding does not occur between AF plies under shear, and that interlamellar connections are governed by collagen and fibrilin rather than elastin The transverse shear modulus was found to be approximately 1.6 times as high in plies the direction of the collagen fibers as in plies across them. Under physiological levels of in-plane shear, fiber bundles stretched and re-oriented linearly. Elastin was found to primarily stiffen plies transversely. We conclude that alterations in the elastic fiber network, as found with IVD herniation and degeneration, can therefore be expected to significantly influence the AF response to shear making it more susceptible to micro failure under bending or torsion loading. PMID:19664773

Michalek, Arthur J; Buckley, Mark R; Bonassar, Lawrence J; Cohen, Itai; Iatridis, James C

2009-01-01

428

Gas modelling in the disc of HD 163296  

NASA Astrophysics Data System (ADS)

We present detailed model fits to observations of the disc around the Herbig Ae star HD 163296. This well-studied object has an age of ~4 Myr, with evidence of a circumstellar disc extending out to ~540 AU. We use the radiation thermo-chemical disc code ProDiMo to model the gas and dust in the circumstellar disc of HD 163296, and attempt to determine the disc properties by fitting to observational line and continuum data. These include new Herschel/PACS observations obtained as part of the open-time key program GASPS (GAS in Protoplanetary Systems), consisting of a detection of the [Oi] 63 ?m line and upper limits for several other far infrared lines. We complement this with continuum data and ground-based observations of the 12CO 3-2, 2-1 and 13CO J = 1-0 line transitions, as well as an upper limit for the H2 0-0 S(1) transition. We explore the effects of stellar ultraviolet variability and dust settling on the line emission, and on the derived disc properties. Our fitting efforts lead to derived gas/dust ratios in the range 9-100, depending on the assumptions made. We note that the line fluxes are sensitive in general to the degree of dust settling in the disc, with an increase in line flux for settled models. This is most pronounced in lines which are formed in the warm gas in the inner disc, but the low excitation molecular lines are also affected. This has serious implications for attempts to derive the disc gas mass from line observations. We derive fractional PAH abundances between 0.007 and 0.04 relative to ISM levels. Using a stellar and UV excess input spectrum based on a detailed analysis of observations, we find that the all observations are consistent with the previously assumed disc geometry.

Tilling, I.; Woitke, P.; Meeus, G.; Mora, A.; Montesinos, B.; Riviere-Marichalar, P.; Eiroa, C.; Thi, W.-F.; Isella, A.; Roberge, A.; Martin-Zaidi, C.; Kamp, I.; Pinte, C.; Sandell, G.; Vacca, W. D.; Ménard, F.; Mendigutía, I.; Duchêne, G.; Dent, W. R. F.; Aresu, G.; Meijerink, R.; Spaans, M.

2012-02-01

429

Probing dust settling in proto-planetary discs with ALMA  

NASA Astrophysics Data System (ADS)

Investigating the dynamical evolution of dust grains in proto-planetary discs is a key issue to understand how planets should form. We identify under which conditions dust settling can be constrained by high angular resolution observations at mm wavelengths, and which observational strategies are suited for such studies. Exploring a large range of models, we generate synthetic images of discs with different degrees of dust settling, and simulate high angular resolution (˜0.05-0.3 arcsec) Atacama Large Millimeter/submillimeter Array (ALMA) observations of these synthetic discs. The resulting data sets are then analysed blindly with homogeneous disc models (where dust and gas are totally mixed) and the derived disc parameters are used as tracers of the settling factor. Our dust discs are partially resolved by ALMA and present some specific behaviours on radial and mainly vertical directions, which can be used to quantify the level of settling. We find out that an angular resolution better than or equal to ˜0.1 arcsec (using 2.3 km baselines at 0.8mm) allows us to constrain the dust scale height and flaring index with sufficient precision to unambiguously distinguish between settled and non-settled discs, provided the inclination is close enough to edge-on (i ? 75°). Ignoring dust settling and assuming hydrostatic equilibrium when analysing such discs affect the derived dust temperature and the radial dependency of the dust emissivity index. The surface density distribution can also be severely biased at the highest inclinations. However, the derived dust properties remain largely unaffected if the disc scale height is fitted separately. ALMA has the potential to test some of the dust settling mechanisms, but for real discs, deviations from ideal geometry (warps, spiral waves) may provide an ultimate limit on the dust settling detection.

Boehler, Y.; Dutrey, A.; Guilloteau, S.; Piétu, V.

2013-05-01

430

Morphological similarities after compression trauma of bovine and human intervertebral discs: Do disc cells have a chance of surviving?  

PubMed

To study the behavior of bovine disc cells and changes in disc matrix following in vitro compression tests; to compare the findings to investigations on human intervertebral discs (IVD) after burst fracture of the cervical spine. Healthy IVDs (n = 21) from three bovine tails were studied at 6 and 12 h post-mortem, with 16 IVDs subjected to impact loading and five as unloaded controls. IVDs (n = 8) from patients with burst fractures were compared to the bovine compression group. Specimens were studied macroscopically, histologically, and ultrastructurally for healthy cells, balloon cells, and disc cell death (DCD). Annulus ruptures were seen in both post-trauma groups, with radial ruptures being present histologically in all loaded bovine discs. Balloon cells were found in some human IVDs and were induced in vitro in bovine loaded discs within a distinct range of absorbed energy. There was a positive correlation between DCD and absorbed energy in all compartments of bovine discs. Both species showed similar patterns of DCD in the different compartments. This study was able to show similarities between both species in cell morphologies and matrix damage. The survival of the disc after substantial compression trauma thus seems to remain highly questionable. PMID:24888549

Sitte, Ingrid; Kathrein, Anton; Klosterhuber, Miranda; Lindtner, Richard Andreas; Neururer, Sabrina Barbara; Rauch, Stefan; Kuhn, Volker; Schmoelz, Werner

2014-09-01