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Sample records for vacuum disc herniation

  1. Herniated Lumbar Disc

    MedlinePLUS

    ... is a herniated disc? Nonsurgical treatment Medication and pain management Surgery What can I expect after surgery? How ... program are important parts of treatment. Medication and pain management Medications used to control pain are called analgesics. ...

  2. Radicular interdural lumbar disc herniation.

    PubMed

    Akhaddar, Ali; Boulahroud, Omar; Elasri, Abad; Elmostarchid, Brahim; Boucetta, Mohammed

    2010-07-01

    Intraradicular lumbar disc herniation is a rare complication of disc disease that is generally diagnosed only during surgery. The mechanism for herniated disc penetration into the intradural space is not known with certainty, but adhesion between the radicular dura and the posterior longitudinal ligament was suggested as the most important condition. The authors report the first case of an intraradicular lumbar disc herniation without subdural penetration; the disc hernia was lodged between the two radicular dura layers. The patient, a 34-year-old soldier, was admitted with a 12-month history of low back pain and episodic left sciatica. Neurologic examination showed a positive straight leg raising test on the left side without sensory, motor or sphincter disturbances. Spinal CT scan and MRI exploration revealed a left posterolateral osteophyte formation at the L5-S1 level with an irregular large disc herniation, which migrated superiorly. An intradural extension was suspected. A left L5 hemilaminectomy and S1 foraminotomy were performed. The exploration revealed a large fragment of disc material located between the inner and outer layers of the left S1 radicular dura. The mass was extirpated without cerebrospinal fluid outflow. The postoperative course was uneventful. Radicular interdural lumbar disc herniation should be suspected when a swollen, hard and immobile nerve root is present intraoperatively. PMID:19888608

  3. The Actual Level of Symptomatic Soft Disc Herniation in Patients with Cervical Disc Herniation

    PubMed Central

    Choi, Su Yong; Kim, Woo Kyung; Son, Seong; Jeong, Tae Seok

    2015-01-01

    Objective The aim of this study was to predict the relationship between the symptomatic disc herniation level and the osteophyte level or decreased disc height in patients with cervical disc herniation. Methods Between January 2011 and December 2012, 69 patients with an osteophyte of the cervical spine underwent surgery at a single center due to soft cervical disc herniation. Data including soft disc herniation level, osteophyte level in the posterior vertebral margin, Cobb's angle, and symptom duration were retrospectively assessed. The patients were divided into three groups according to the relationship between the degenerative change level and the level of reported symptoms. Results Among the 69 patients, 48 (69.6%) showed a match between osteophyte level and soft disc herniation level. Disc herniation occurred at the adjacent segment to degenerative osteophyte level in 12 patients (17.4%) and at both the adjacent and the osteophyte level in nine (13.0%). There was no significant difference in Cobb's angle or duration among the three groups. Osteophyte type was not significant. The mean disc height of the prominent degenerative change level group was lower than the adjacent segment level, but this was not significant. Conclusion Soft cervical disc herniation usually occurs at the level an osteophyte forms. However, it may also occur at segments adjacent to that of the osteophyte level. Therefore, in patients with cervical disc herniation, although a prominent osteophyte alone may appear on plain radiography, we must suspect the presence of soft disc herniation at other levels. PMID:26512266

  4. [Repeated operations for recurrent lumbar disc herniations].

    PubMed

    Kloc, W; Imieli?ski, B L; Wasilewski, W; Jende, P; Puzyrewski, R

    1999-01-01

    A study of 73 patients who underwent reoperation for persistent or new complaints following initial lumbar discectomy is presented. 32 patients showed true recurrence of disc herniation (6 on the contralateral side) and 41 at a different level. 14 patients needed 3rd operation. Final results were evaluated using the Functional Economic Rating Scale elaborated by Prolo. Mean score for group operated on twice was 8.1 according to Prolo and 7.1 for group operated on 3 times. PMID:10791038

  5. Tissue Engineering a Biological Repair Strategy for Lumbar Disc Herniation

    PubMed Central

    O'Connell, Grace D.; Leach, J. Kent; Klineberg, Eric O.

    2015-01-01

    Abstract The intervertebral disc is a critical part of the intersegmental soft tissue of the spinal column, providing flexibility and mobility, while absorbing large complex loads. Spinal disease, including disc herniation and degeneration, may be a significant contributor to low back pain. Clinically, disc herniations are treated with both nonoperative and operative methods. Operative treatment for disc herniation includes removal of the herniated material when neural compression occurs. While this strategy may have short-term advantages over nonoperative methods, the remaining disc material is not addressed and surgery for mild degeneration may have limited long-term advantage over nonoperative methods. Furthermore, disc herniation and surgery significantly alter the mechanical function of the disc joint, which may contribute to progression of degeneration in surrounding tissues. We reviewed recent advances in tissue engineering and regenerative medicine strategies that may have a significant impact on disc herniation repair. Our review on tissue engineering strategies focuses on cell-based and inductive methods, each commonly combined with material-based approaches. An ideal clinically relevant biological repair strategy will significantly reduce pain and repair and restore flexibility and motion of the spine. PMID:26634189

  6. Percutaneous treatment of cervical and lumbar herniated disc.

    PubMed

    Kelekis, A; Filippiadis, D K

    2015-05-01

    Therapeutic armamentarium for symptomatic intervertebral disc herniation includes conservative therapy, epidural infiltrations (interlaminar or trans-foraminal), percutaneous therapeutic techniques and surgical options. Percutaneous, therapeutic techniques are imaging-guided, minimally invasive treatments for intervertebral disc herniation which can be performed as outpatient procedures. They can be classified in 4 main categories: mechanical, thermal, chemical decompression and biomaterials implantation. Strict sterility measures are a prerequisite and should include extensive local sterility and antibiotic prophylaxis. Indications include the presence of a symptomatic, small to medium sized contained intervertebral disc herniation non-responding to a 4-6 weeks course of conservative therapy. Contraindications include sequestration, infection, segmental instability (spondylolisthesis), uncorrected coagulopathy or a patient unwilling to provide informed consent. Decompression techniques are feasible and reproducible, efficient (75-94% success rate) and safe (>0.5% mean complications rate) therapies for the treatment of symptomatic intervertebral disc herniation. Percutaneous, imaging guided, intervertebral disc therapeutic techniques can be proposed either as an initial treatment or as an attractive alternative prior to surgery for the therapy of symptomatic herniation in both cervical and lumbar spine. This article will describe the mechanism of action for different therapeutic techniques applied to intervertebral discs of cervical and lumbar spine, summarize the data concerning safety and effectiveness of these treatments, and provide a rational approach for the therapy of symptomatic intervertebral disc herniation in cervical and lumbar spine. PMID:24673977

  7. Concomitance of fibromyalgia syndrome and cervical disc herniation

    PubMed Central

    Güler, Mustafa; Ayd?n, Teoman; Akgöl, Erdal; Ta?p?nar, Özgür

    2015-01-01

    [Purpose] Fibromyalgia syndrome (FMS) and cervical disc herniation (CDH) are a common diseases commonly encountered in physical therapy clinics. There are also patients who have both of these diseases. In this study we aim to investigated whether FMS is a risk factor for cervical disc herniation and the frequency of their coincident occurrence. [Subjects and Methods] Thirty-five patients having a primary FMS diagnosis according to the American Rheumatism Association criteria are taken into consideration and a control group were the subjects of this study. The two groups were compared with respect to cervical disc hernia using cervical region MRI. [Results] The distribution of disc hernia of 6 fibromyalgia patients who had cervical discopathy was: 16.6% C2–3, 16.6% C5–6, 16.6% C6–7, 33.3% C4–5, C5–6 (two levels in two patients) and 16.6% C4–5, C5–6, C7–1 (three levels in one patient) . The herniation directions were given as: central in 5 levels, right paramedian in 1 level, and left paramedian disc hernia in 1 level. There were 4 cervical disk hernia in the control group. The herniation direction were central in two, right paramedian in one, and left paramedian in one patient. [Conclusion] In this study, the existence of cervical disc herniation in fibromyalgia patients was found to be not different from the normal population. PMID:25931731

  8. Treatment of lumbar disc herniation: Evidence-based practice

    PubMed Central

    Schoenfeld, Andrew J; Weiner, Bradley K

    2010-01-01

    Clinical question: What is the best treatment for lumbar disc herniations? Results: For patients failing six weeks of conservative care, the current literature supports surgical intervention or prolonged conservative management as appropriate treatment options for lumbar radiculopathy in the setting of disc herniation. Surgical intervention may result in more rapid relief of symptoms and restoration of function. Implementation: While surgery appears to provide more rapid relief, many patients will gradually get better with continued nonoperative management; thus, patient education and active participation in decision-making is vital. PMID:20689695

  9. Plasma-mediated disc decompression for contained cervical disc herniation: results through 5 years.

    PubMed

    Cesaroni, Alessandro; Nardi, Pier Vittorio

    2011-01-01

    Conventional treatment for cervical disc herniations often defaults to open cervical discectomy, potentially supplemented by intervertebral fusion. Newer treatment strategies focus on percutaneous, minimally invasive procedures which are capable of resolving herniation pathology while offering decreased morbidity and convalescence time when compared to fusion. In cases where patients complain of radicular and neck pain symptoms related to a contained herniated disc, plasma disc decompression may be used as a minimally invasive treatment option on the cervical intervertebral discs.Three hundred and forty-nine patients who presented with a contained herniated cervical disc or focal protrusion causing pain associated with cervical nerve root compression were treated between January 2003 and May 2007. This case series study was conducted to evaluate clinical results through 1 year postoperatively. PMID:21107946

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

    NASA Astrophysics Data System (ADS)

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

    2005-07-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

    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%.

  12. Low back pain associated with lumbar disc herniation: role of moderately degenerative disc and annulus fibrous tears.

    PubMed

    Yang, Hao; Liu, Hui; Li, Zemin; Zhang, Kuibo; Wang, Jianru; Wang, Hua; Zheng, Zhaomin

    2015-01-01

    Lumbar disc herniation is one of the most common spinal degenerative disorders which may lead to low back pain (LBP) and radicular leg pain. However, it remains difficult to diagnose a degenerative herniated disc as the LBP generator in clinical practice. The purpose of this study is to explore the characteristic changes of a herniated disc causing LBP on MRI and to clarify the underlying role of inflammatory mediators and annulus fibrous (AF) tears in LBP generation associated with disc herniation. We prospectively collected intervertebral disc specimens and MRI from 57 single-segment disc herniation patients with radiculopathy. All subjects were grouped according to LBP occurrence or disc degeneration severity for the comparison of inflammatory mediators' expression and AF tears occurrence (High Intensity Zone, HIZ, on MRI). LBP incidence under circumstances of different degeneration severity with or without HIZ was further analyzed. Both LBP incidence and Inflammatory mediators expression in moderately degenerated group was higher than mildly and severely degenerative groups. HIZ incidence was higher in moderately and severely degenerated groups. LBP incidence in the patients with both moderately degenerated discs and HIZ was 86.7%, much higher than the rest of the patient population. In conclusion, the high expression of inflammatory mediators with AF tears causes LBP associated with disc herniation. Moderately degenerative disc with HIZ is MRI morphological change of herniated disc causing LBP, which can be applied to diagnose LBP. PMID:25932092

  13. Anterior Herniation of Partially Calcified and Degenerated Cervical Disc Causing Dysphagia

    PubMed Central

    Turk, Cezmi Cagri; Yildirim, Ali Erdem; Dalgic, Ali

    2015-01-01

    We report a rare case of anterior cervical disc herniation associated with dysphagia. A 32-year-old man presented with complaints of dysphagia and concomitant pain in the right arm resistant to conservative therapy. On physical examination with respect to the muscle strength, the right shoulder abduction and flexion of the forearm were 3/5. Lateral X-ray revealed calcified osteophytes at the anterior C4-5 level. Magnetic resonance imaging showed soft disc herniation involving the right C6 root at the C5-6 level and anterior herniation of the C4-5 cervical disc. Anterior discectomies for C4-5 and C5-6 levels stabilized and ameliorated the dysphagia and pain. Cervical disc herniation usually presents with radicular findings. However, dysphagia may be an uncommon presentation. Anterior cervical disc herniation should be considered in a patient presenting with dysphagia. PMID:26240723

  14. Anterior Herniation of Partially Calcified and Degenerated Cervical Disc Causing Dysphagia.

    PubMed

    Ozdol, Cagatay; Turk, Cezmi Cagri; Yildirim, Ali Erdem; Dalgic, Ali

    2015-08-01

    We report a rare case of anterior cervical disc herniation associated with dysphagia. A 32-year-old man presented with complaints of dysphagia and concomitant pain in the right arm resistant to conservative therapy. On physical examination with respect to the muscle strength, the right shoulder abduction and flexion of the forearm were 3/5. Lateral X-ray revealed calcified osteophytes at the anterior C4-5 level. Magnetic resonance imaging showed soft disc herniation involving the right C6 root at the C5-6 level and anterior herniation of the C4-5 cervical disc. Anterior discectomies for C4-5 and C5-6 levels stabilized and ameliorated the dysphagia and pain. Cervical disc herniation usually presents with radicular findings. However, dysphagia may be an uncommon presentation. Anterior cervical disc herniation should be considered in a patient presenting with dysphagia. PMID:26240723

  15. Occupational risk factors for symptomatic lumbar disc herniation; a case-control study

    PubMed Central

    Seidler, A; Bolm-Audorff, U; Siol, T; Henkel, N; Fuchs, C; Schug, H; Leheta, F; Marquardt, G; Schmitt, E; Ulrich, P; Beck, W; Missalla, A; Elsner, G

    2003-01-01

    Background: Previous studies mostly did not separate between symptomatic disc herniation combined with osteochondrosis/spondylosis of the lumbar spine and symptomatic disc herniation in radiographically normal intervertebral spaces. This may at least in part explain the differences in the observed risk patterns. Aims: To investigate the possible aetiological relevance of physical and psychosocial workload to lumbar disc herniation with and without concomitant osteochondrosis/spondylosis. Methods: A total of 267 cases with acute lumbar disc herniation (in two practices and four clinics) and 197 control subjects were studied. Data were gathered in a structured personal interview and analysed using logistic regression to control for age, region, nationality, and diseases affecting the lumbar spine. Cases without knowledge about osteochondrosis/spondylosis (n=42) were excluded from analysis. Risk factors were examined separately for those cases with (n=131) and without (n=94) radiographically diagnosed concomitant osteochondrosis or spondylosis. Results: There was a statistically significant positive association between extreme forward bending and lumbar disc herniation with, as well as without concomitant osteochondrosis/spondylosis. There was a statistically significant relation between cumulative exposure to weight lifting or carrying and lumbar disc herniation with, but not without, concomitant osteochondrosis/spondylosis. Cases with disc herniation reported time pressure at work as well as psychic strain through contact with clients more frequently than control subjects. Conclusions: Further larger studies are needed to verify the concept of distinct aetiologies of lumbar disc herniation in relatively younger persons with otherwise normal discs and of disc herniation in relatively older persons with structurally damaged discs. PMID:14573712

  16. Lumbar disc herniation with contralateral radiculopathy: do we neglect the epidural fat?

    PubMed

    Yang, Jun-Song; Zhang, Dong-Jie; Hao, Ding-Jun

    2015-01-01

    Lumbar disc herniation (LDH) is the most common cause of radiculopathy, whose pathological entity underlying nerve root compression is usually on the same side as the symptoms. However, LDH causing contralateral radiculopathy are sometimes encountered by pain physicians. There have been tremendous developments in the treatment options for LDH; the situation of LDH causing contralateral radiculopathy is indeed a dilemma for some pain physicians. We will report a case of a patient with a L4-5 disc herniation whose left herniated disc caused radiculopathy on the right side. After a percutaneous lumbar endoscopic discectomy via the side ipsilateral to the symptomatic side, this case obtained a significant symptom remission. The migrated epidural fat is discussed as a cause of associated contralateral neurological deficit. Only via a surgical approach ipsilateral to the herniated side, could there be a clinical improvement postoperatively. PMID:25794228

  17. Target radiofrequency combined with collagenase chemonucleolysis in the treatment of lumbar intervertebral disc herniation.

    PubMed

    Zhang, Daying; Zhang, Yong; Wang, Zhijian; Zhang, Xuexue; Sheng, Mulan

    2015-01-01

    Both target radiofrequency thermocoagulation and collagenase chemonucleolysis are effective micro-invasive therapy means for lumbar intervertebral disc herniation. In order to analyze the clinical effects of target radiofrequency thermocoagulation combined with collagenase chemonucleolysis on lumbar intervertebral disc herniation, the contents of hydroxyproline and glycosaminoglycan were measured and the histological changes of nucleus pulposus was detected in the vitro experiments. Radiofrequency thermocoagulation reduced the hydrolyzation of herniated nucleus pulposus caused by collagenase, as well as the content of hydroxyproline and glycosaminoglycan. Furthermore, 236 patients with lumbar intervertebral disc herniation were treated by target radiofrequency thermocoagulation combined with collagenase chemonucleolysis. The efficiency was evaluated according to Macnab criteria, and the index of lumbar disc herniation (IDH) was compared pre-operation with 3 months post-operation. The post-operative good rate was 66.5% (157/236) at 2 weeks post-operation, and 88.1% (208/236) at 3 months post-operation. In the post-operative follow-up exam, 86.8% of the re-examined cases demonstrated smaller or ablated protrusion, with reduced IDH values from pre-operation, which was statistically significant. No serious complications were detected intra-operatively and post-operatively. In conclusion, target radiofrequency combined with collagenase chemonucleolysis was an effective and safe method for treatment of lumbar intervertebral disc herniation. PMID:25785026

  18. Target radiofrequency combined with collagenase chemonucleolysis in the treatment of lumbar intervertebral disc herniation

    PubMed Central

    Zhang, Daying; Zhang, Yong; Wang, Zhijian; Zhang, Xuexue; Sheng, Mulan

    2015-01-01

    Both target radiofrequency thermocoagulation and collagenase chemonucleolysis are effective micro-invasive therapy means for lumbar intervertebral disc herniation. In order to analyze the clinical effects of target radiofrequency thermocoagulation combined with collagenase chemonucleolysis on lumbar intervertebral disc herniation, the contents of hydroxyproline and glycosaminoglycan were measured and the histological changes of nucleus pulposus was detected in the vitro experiments. Radiofrequency thermocoagulation reduced the hydrolyzation of herniated nucleus pulposus caused by collagenase, as well as the content of hydroxyproline and glycosaminoglycan. Furthermore, 236 patients with lumbar intervertebral disc herniation were treated by target radiofrequency thermocoagulation combined with collagenase chemonucleolysis. The efficiency was evaluated according to Macnab criteria, and the index of lumbar disc herniation (IDH) was compared pre-operation with 3 months post-operation. The post-operative good rate was 66.5% (157/236) at 2 weeks post-operation, and 88.1% (208/236) at 3 months post-operation. In the post-operative follow-up exam, 86.8% of the re-examined cases demonstrated smaller or ablated protrusion, with reduced IDH values from pre-operation, which was statistically significant. No serious complications were detected intra-operatively and post-operatively. In conclusion, target radiofrequency combined with collagenase chemonucleolysis was an effective and safe method for treatment of lumbar intervertebral disc herniation. PMID:25785026

  19. Who should have Surgery for an Intervertebral Disc Herniation?

    PubMed Central

    Pearson, Adam; Lurie, Jon; Tosteson, Tor; Zhao, Wenyan; Abdu, William; Mirza, Sohail; Weinstein, James

    2012-01-01

    Study Design Combined prospective randomized controlled trial and observational cohort study of intervertebral disc herniation (IDH), an as-treated analysis. Objective To determine modifiers of the treatment effect (TE) of surgery (the difference between surgical and nonoperative outcomes) for intervertebral disc herniation (IDH) using subgroup analysis. Summary of Background Data SPORT demonstrated a positive surgical TE for IDH at the group level. However, individual characteristics may affect TE. No prior studies have evaluated TE modifiers in IDH. Methods IDH patients underwent either discectomy (n=788) or nonoperative care (n=404) and were analyzed according to treatment received. Thirty-seven baseline variables were used to define subgroups for calculating the time-weighted average TE for the Oswestry Disability Index (ODI) over 4 years (TE=?ODIsurgery-?ODInonoperative). Variables with significant subgroup by* treatment interactions (p<0.1) were simultaneously entered into a multivariate model to select independent TE predictors. Results All analyzed subgroups improved significantly more with surgery than with nonoperative treatment (p<0.05). In minimally adjusted univariate analyses: being married, absence of joint problems, worsening symptom trend at baseline, high school education or less, older age, no worker’s compensation, longer duration of symptoms, and an SF-36 mental component score (MCS) less than 35 were associated with greater TEs. Multivariate analysis demonstrated: being married (TE ?15.8 vs. ?7.7 single, p<0.001), absence of joint problems (TE ?14.6 vs. ?10.3 joint problems, p=0.012), and worsening symptoms (TE ?15.9 vs. ?11.8 stable symptoms, p=0.032) were independent TE modifiers. TE’s were greatest in married patients with worsening symptoms (?18.3) vs. single patients with stable symptoms (?7.8). Conclusions IDH patients who met strict inclusion criteria improved more with surgery than with nonoperative treatment, regardless of specific characteristics. However, being married, without joint problems, and worsening symptom trend at baseline were associated with a greater treatment effect. PMID:21681140

  20. Role of interleukin-17 in chondrocytes of herniated intervertebral lumbar discs

    PubMed Central

    TIAN, PENG; LI, ZHI-JUN; FU, XIN; MA, XIN-LONG

    2015-01-01

    Lumbar disc herniation (LDH) is a common cause of lumbosacral radiculopathy. An autoimmune response to a herniated nucleus pulposus (NP) has been suggested to play an important role in the initiation of radiculopathy. Interleukin-17 (IL-17) is a cytokine associated with inflammation and autoimmunity. The presence of IL-17 has been studied in patients with LDH; however, extensive investigation into the expression of IL-17 in different disc pathologies of LDH has not yet been conducted. The aim of the present study was to investigate the role of neovascularization and hypertrophic chondrocytes in herniated intervertebral lumbar discs. Fifty-two intervertebral lumbar disc specimens were extracted from 46 patients with LDH and were subsequently classified as either contained or non-contained disc herniation (CDH and NCDH, respectively). The specimens were stained with hematoxylin and eosin or toluidine blue, or were immunostained with polyclonal antibodies to IL-17 using the streptavidin-peroxidase method. The neovascular tissue and staining results were graded to establish the histological differences between the two herniation types. The intervertebral discs (IVDs) obtained from patients with NCDH showed significantly more neovascularization and granulation tissue than the discs obtained from patients with CDH (P<0.05). Furthermore, hypertrophic chondrocytes were more abundant in the NCDH specimens than in the CDH specimens (P<0.05). Similarly, the number of IL-17-immunoreactive cells was significantly higher in the NCDH specimens than that in the CDH specimens (P<0.01). In conclusion, local inflammation and autoreactive immune activation may play an important role in the pathogenesis of LDH. These results also suggest a role of chondrocytes in the repair of herniated IVDs. PMID:26170916

  1. Minimally invasive tubular microdiscectomy for recurrent lumbar disc herniation.

    PubMed

    Hubbe, Ulrich; Franco-Jimenez, Pamela; Klingler, Jan-Helge; Vasilikos, Ioannis; Scholz, Christoph; Kogias, Evangelos

    2016-01-01

    OBJECT The aim of the study was to investigate the safety and efficacy of minimally invasive tubular microdiscectomy for the treatment of recurrent lumbar disc herniation (LDH). As opposed to endoscopic techniques, namely microendoscopic and endoscopic transforaminal discectomy, this microscopically assisted technique has never been used for the treatment of recurrent LDH. METHODS Thirty consecutive patients who underwent minimally invasive tubular microdiscectomy for recurrent LDH were included in the study. The preoperative and postoperative visual analog scale (VAS) scores for pain, the clinical outcome according to modified Macnab criteria, and complications were analyzed retrospectively. The minimum follow-up was 1.5 years. Student t-test with paired samples was used for the statistical comparison of pre- and postoperative VAS scores. A p value < 0.05 was considered to be statistically significant. RESULTS The mean operating time was 90 ± 35 minutes. The VAS score for leg pain was significantly reduced from 5.9 ± 2.1 preoperatively to 1.7 ± 1.3 postoperatively (p < 0.001). The overall success rate (excellent or good outcome according to Macnab criteria) was 90%. Incidental durotomy occurred in 5 patients (16.7%) without neurological consequences, CSF fistula, or negative influence to the clinical outcome. Instability occurred in 2 patients (6.7%). CONCLUSIONS The clinical outcome of minimally invasive tubular microdiscectomy is comparable to the reported success rates of other minimally invasive techniques. The dural tear rate is not associated to higher morbidity or worse outcome. The technique is an equally effective and safe treatment option for recurrent LDH. PMID:26384131

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

    PubMed

    Saberi, Hooshang; Isfahani, Arash Vatankhahan

    2008-01-01

    To evaluate the surgical outcome in terms of functional and subjective recovery, patients who needed discectomies at L1-L2, 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. We prospectively enrolled 50 consecutive patients, referred to our center, who had L1-L2, L2-L3 and L3-L4 herniations and required surgical intervention. Likewise, a comparative group of 50 consecutive patients with herniations at L4-L5 and L5-S1 were selected. All 100 patients were treated and followed for a 1 year period. Physical examination findings as well as Oswestry Disability Questionnaire before surgery were recorded. After 1 year, patients were requested to fill the same questionnaire. Significant decline in the Oswestry Disability Index (ODI) scores was considered to be a measure of functional improvement and recovery. The mean age of patients with upper lumbar disc herniation (L1-L2, L2-L3, L3-L4) was 45.7 years and patients with lower lumbar disc herniation (L4-L5, L5-S1) had a mean age of 41.2 years. There was no statistically significant difference in age between the two groups. The preoperative Oswestry Disability (ODI) Index score had a statistically significant impact on ODI score improvement after surgery in both lower and upper lumbar disc groups. All 100 patients with either lower or upper lumbar disc herniation had statistically significant ODI change after surgical intervention (P < 0.0001 for both groups). However, patients with upper disc herniations and moderate preoperative disability (ODI of 21-40%) did not show significant improvement, while patients with ODI greater than 40% had significant reduction (P = 0.018). Surprisingly, as many as 25% of the former had even an increase in ODI scores after surgery. Gender was also a conspicuous factor in determining the surgical outcome of patients with upper lumbar disc herniation, and male patients had more reduction in ODI score than female patients (P = 0.007). Since the functional recovery in patients with herniated lumbar disc, especially upper lumbar herniation, is influenced by preoperative ODI scores, the use of ODI or any other standard pain assessment tool is a sensible consideration as an inherent investigative method to preclude unfavorable surgical outcome. PMID:17972115

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

    PubMed Central

    Isfahani, Arash Vatankhahan

    2007-01-01

    To evaluate the surgical outcome in terms of functional and subjective recovery, patients who needed discectomies at L1–L2, 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. We prospectively enrolled 50 consecutive patients, referred to our center, who had L1–L2, L2–L3 and L3–L4 herniations and required surgical intervention. Likewise, a comparative group of 50 consecutive patients with herniations at L4–L5 and L5–S1 were selected. All 100 patients were treated and followed for a 1 year period. Physical examination findings as well as Oswestry Disability Questionnaire before surgery were recorded. After 1 year, patients were requested to fill the same questionnaire. Significant decline in the Oswestry Disability Index (ODI) scores was considered to be a measure of functional improvement and recovery. The mean age of patients with upper lumbar disc herniation (L1–L2, L2–L3, L3–L4) was 45.7 years and patients with lower lumbar disc herniation (L4–L5, L5–S1) had a mean age of 41.2 years. There was no statistically significant difference in age between the two groups. The preoperative Oswestry Disability (ODI) Index score had a statistically significant impact on ODI score improvement after surgery in both lower and upper lumbar disc groups. All 100 patients with either lower or upper lumbar disc herniation had statistically significant ODI change after surgical intervention (P < 0.0001 for both groups). However, patients with upper disc herniations and moderate preoperative disability (ODI of 21–40%) did not show significant improvement, while patients with ODI greater than 40% had significant reduction (P = 0.018). Surprisingly, as many as 25% of the former had even an increase in ODI scores after surgery. Gender was also a conspicuous factor in determining the surgical outcome of patients with upper lumbar disc herniation, and male patients had more reduction in ODI score than female patients (P = 0.007). Since the functional recovery in patients with herniated lumbar disc, especially upper lumbar herniation, is influenced by preoperative ODI scores, the use of ODI or any other standard pain assessment tool is a sensible consideration as an inherent investigative method to preclude unfavorable surgical outcome. PMID:17972115

  4. Generalized Joint Laxity is Associated with Primary Occurrence and Treatment Outcome of Lumbar Disc Herniation

    PubMed Central

    Han, Woo Jin; Kim, Hong-Bae; Lee, Gun Woo; Choi, Jung Heum; Jo, Won Jin

    2015-01-01

    Background We investigated relationships between generalized joint laxity and primary lumbar disc herniation occurrence and compared clinical outcomes after conservative treatment in lumbar disc herniation patients with and without generalized joint laxity. Methods The study group included 128 men, and the control group included 276 men matched for age and body mass index with the study group. The primary outcome measure was the presence or absence of generalized joint laxity using the Beighton scale. Clinical outcomes measured by the visual analog scale and the Oswestry disability index 2 years after conservative treatment were the secondary outcome measure. Results Generalized joint laxity prevalence was 13.2% in the study group and 5.1% in the control group, a significant difference (P=0.01). Spearman correlation analysis revealed that weight (r=0.162, P=0.03), body mass index (r=0.131, P=0.03), and generalized joint laxity (r=0.372, P<0.01) significantly correlated with lumbar disc herniation occurrence. In multivariate regression analysis, generalized joint laxity was the only significant lumbar disc herniation predictor (P=0.002; 95% confidence interval, 1.08 to 5.26). Generalized joint laxity in lumbar disc herniation patients was associated with worse clinical outcomes after conservative treatment measured by visual analog scale scores for lower extremity pain (P=0.02), lower back pain (P=0.03), and Oswestry disability index scores (P=0.03). Conclusion Generalized joint laxity might be associated with lumbar disc herniation occurrence and might also be a negative predictor of worse clinical outcomes after conservative treatment. PMID:26019764

  5. [Pain related impairment and the ability to function in herniated disc patients during rehabilitation].

    PubMed

    Kitze, K; Rust, V; Angermeyer, M C

    2007-12-01

    Herniated discs usually occur in middle aged persons. For some the pain is so serious that an operation is necessary. Yet despite modern micro-surgical methods for operations, approximately one-third of the patients continue to report ongoing limitations. The reasons for insufficient success of therapy however lie not only in the illness as such. This study is intended to examine the changes in the subjective success parameters of pain-related impairment and the ability to function in herniated disc patients during rehabilitation. Using multivariate analyses, the influence of sociodemographic, illness-specific, work-related and mental variables on changes in goal variables is shown. 214 herniated disc patients were interviewed before the operation, after post-operative therapy, and six months after surgery. Before their operation, herniated disc patients experienced a severe limitation of activity and ability in everyday function due to pain. About three-fourth of the patients experienced significant improvement in both variables after the operation and post-operative therapy. The influence factors for a successful therapy outcome were male gender and higher educational level. Risk factors were increasing age, a desire for a pension, severe illness symptoms and severe pre-operative depression. In addition to somatic therapy, higher risk patients should receive psychological or social and employment counselling as a support to post-operative therapy. PMID:18188804

  6. Genotypic and Antimicrobial Characterisation of Propionibacterium acnes Isolates from Surgically Excised Lumbar Disc Herniations

    PubMed Central

    Rollason, Jess; Albert, Hanne B.; Barnard, Emma; Worthington, Tony; Hilton, Anthony C.; Vernallis, Ann; Patrick, Sheila; Elliott, Tom

    2013-01-01

    The anaerobic skin commensal Propionibacterium acnes is an underestimated cause of human infections and clinical conditions. Previous studies have suggested a role for the bacterium in lumbar disc herniation and infection. To further investigate this, five biopsy samples were surgically excised from each of 64 patients with lumbar disc herniation. P. acnes and other bacteria were detected by anaerobic culture, followed by biochemical and PCR-based identification. In total, 24/64 (38%) patients had evidence of P. acnes in their excised herniated disc tissue. Using recA and mAb typing methods, 52% of the isolates were type II (50% of culture-positive patients), while type IA strains accounted for 28% of isolates (42% patients). Type III (11% isolates; 21% patients) and type IB strains (9% isolates; 17% patients) were detected less frequently. The MIC values for all isolates were lowest for amoxicillin, ciprofloxacin, erythromycin, rifampicin, tetracycline, and vancomycin (?1mg/L). The MIC for fusidic acid was 1-2 mg/L. The MIC for trimethoprim and gentamicin was 2 to ?4?mg/L. The demonstration that type II and III strains, which are not frequently recovered from skin, predominated within our isolate collection (63%) suggests that the role of P. acnes in lumbar disc herniation should not be readily dismissed. PMID:24066290

  7. Genotypic and antimicrobial characterisation of Propionibacterium acnes isolates from surgically excised lumbar disc herniations.

    PubMed

    Rollason, Jess; McDowell, Andrew; Albert, Hanne B; Barnard, Emma; Worthington, Tony; Hilton, Anthony C; Vernallis, Ann; Patrick, Sheila; Elliott, Tom; Lambert, Peter

    2013-01-01

    The anaerobic skin commensal Propionibacterium acnes is an underestimated cause of human infections and clinical conditions. Previous studies have suggested a role for the bacterium in lumbar disc herniation and infection. To further investigate this, five biopsy samples were surgically excised from each of 64 patients with lumbar disc herniation. P. acnes and other bacteria were detected by anaerobic culture, followed by biochemical and PCR-based identification. In total, 24/64 (38%) patients had evidence of P. acnes in their excised herniated disc tissue. Using recA and mAb typing methods, 52% of the isolates were type II (50% of culture-positive patients), while type IA strains accounted for 28% of isolates (42% patients). Type III (11% isolates; 21% patients) and type IB strains (9% isolates; 17% patients) were detected less frequently. The MIC values for all isolates were lowest for amoxicillin, ciprofloxacin, erythromycin, rifampicin, tetracycline, and vancomycin (?1 mg/L). The MIC for fusidic acid was 1-2 mg/L. The MIC for trimethoprim and gentamicin was 2 to ?4 ?mg/L. The demonstration that type II and III strains, which are not frequently recovered from skin, predominated within our isolate collection (63%) suggests that the role of P. acnes in lumbar disc herniation should not be readily dismissed. PMID:24066290

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

    PubMed Central

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

    2014-01-01

    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

  9. Retrolisthesis and lumbar disc herniation: a postoperative assessment of patient function

    PubMed Central

    Kang, Kevin K.; Shen, Michael S.; Zhao, Wenyan; Lurie, Jon D.; Razi, Afshin E.

    2013-01-01

    BACKGROUND CONTEXT The presence of retrolisthesis has been associated with the degenerative changes of the lumbar spine. However, retrolisthesis in patients with L5–S1 disc herniation has not been shown to have a significant relationship with worse baseline pain or function. Whether it can affect the outcomes after discectomy, is yet to be established. PURPOSE The purpose of this study was to determine the relationship between retrolisthesis (alone or in combination with other degenerative conditions) and postoperative low back pain, physical function, and quality of life. This study was intended to be a follow-up to a previous investigation that looked at the preoperative assessment of patient function in those with retrolisthesis and lumbar disc herniation. STUDY DESIGN Cross-sectional study. PATIENT SAMPLE Patients enrolled in SPORT (Spine Patient Outcomes Research Trial) who had undergone L5–S1 discectomy and had a complete magnetic resonance imaging scan available for review (n=125). Individuals with anterolisthesis were excluded. OUTCOME MEASURES Time-weighted averages over 4 years for the Short Form (SF)-36 bodily pain scale, SF-36 physical function scale, Oswestry Disability Index (ODI), and Sciatica Bothersomeness Index (SBI). METHODS Retrolisthesis was defined as a posterior subluxation of 8% or more. Disc degeneration was defined as any loss of disc signal on T2 imaging. Modic changes were graded 1 to 3 and collectively classified as vertebral end plate degenerative changes. The presence of facet arthropathy and ligamentum flavum hypertrophy was classified jointly as posterior degenerative changes. Longitudinal regression models were used to compare the time-weighted outcomes over 4 years. RESULTS Patients with retrolisthesis did significantly worse with regard to bodily pain and physical function over 4 years. However, there were no significant differences in terms of ODI or SBI. Similarly, retrolisthesis was not a significant factor in the operative time, blood loss, lengths of stay, complications, rate of additional spine surgeries, or recurrent disc herniations. Disc degeneration, modic changes, and posterior degenerative changes did not affect the outcomes. CONCLUSIONS Although retrolisthesis in patients with L5–S1 disc herniation did not affect the baseline pain or function, postoperative outcomes appeared to be somewhat worse. It is possible that the contribution of pain or dysfunction related to retrolisthesis became more evident after removal of the disc herniation. PMID:23201024

  10. Chemonucleolysis for relief of sciatica due to a herniated intervertebral disc.

    PubMed Central

    McCulloch, J A

    1981-01-01

    Chemonucleolysis is the nonoperative chemical removal of displaced lumbar disc material. The enzyme chymopapain, which has a wide margin of safety between its effective therapeutic and toxic doses, is effective in the management of sciatica due to a herniated intervertebral disc. The patient will have leg pain as the dominant symptom and a 50% reduction in straight-leg raising with or without bowstring discomfort and crossover pain. Neurologic symptoms and signs are usual, as are abnormal results of contrast studies, which will verify the level of involvement. In 220 randomly selected patients who met criteria for the diagnosis of sciatica due to a herniated intervertebral disc and did not have psychogenic or nonorganic spinal pain, a spinal stenosis or a history of a previous, unsuccessful operation to relieve the sciatica, chemonucleolysis had a success rate of 80%. The only complications were a severe anaphylactic reaction in two patients and lesser, delayed reactions in five others. All of the reactions were successfully treated. Of the 45 patients in whom chemonucleolysis was unsuccessful, 38 underwent a laminectomy. In 3 of the 38 the results of chemonucleolysis were initially good, but later the disc herniation recurred; thus, the long-term treatment failure rate was 1.4%. PMID:7011530

  11. Comparison of Percutaneous Endoscopic Lumbar Discectomy and Open Lumbar Microdiscectomy for Recurrent Disc Herniation

    PubMed Central

    Lee, Dong Yeob; Shim, Chan Shik; Ahn, Yong; Choi, Young-Geun; Kim, Ho Jin

    2009-01-01

    Objective The purpose of this study was to compare clinical and radiological outcomes of percutaneous endoscopic lumbar discectomy (PELD) and open lumbar microdiscectomy (OLM) for recurrent disc herniation. Methods Fifty-four patients, who underwent surgery, either PELD (25 patients) or repeated OLM (29 patients), due to recurrent disc herniation at L4-5 level, were divided into two groups according to the surgical methods. Excluded were patients with sequestrated disc, calcified disc, severe neurological deficit, or instability. Clinical outcomes were assessed using Visual Analogue Scale (VAS) score and Oswestry Disability Index (ODI). Radiological variables were assessed using plain radiography and/or magnetic resonance imaging. Results Mean operating time and hospital stay were significantly shorter in PELD group (45.8 minutes and 0.9 day, respectively) than OLM group (73.8 minutes and 3.8 days, respectively) (p < 0.001). Complications occurred in 4% in PELD group and 10.3% in OLM group in the perioperative period. At a mean follow-up duration of 34.2 months, the mean improvements of back pain, leg pain, and functional improvement were 4.0, 5.5, and 40.9% for PELD group and 2.3, 5.1, and 45.0% for OLM group, respectively. Second recurrence occurred in 4% after PELD and 10.3% after OLM. Disc height did not change after PELD, but significantly decreased after OLM (p = 0.0001). Neither sagittal rotation angle nor volume of multifidus muscle changed significantly in both groups. Conclusion Both PELD and repeated OLM showed favorable outcomes for recurrent disc herniation, but PELD had advantages in terms of shorter operating time, hospital stay, and disc height preservation. PMID:20062565

  12. A history of lumbar disc herniation from Hippocrates to the 1990s.

    PubMed

    Truumees, Eeric

    2015-06-01

    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

  13. The Impact of Epidural Steroid Injections on the Outcomes of Patients Treated for Lumbar Disc Herniation

    PubMed Central

    Radcliff, Kristen; Hilibrand, Alan; Lurie, Jon D.; Tosteson, Tor D.; Delasotta, Lawrence; Rihn, Jeffrey; Zhao, Wenyan; Vaccaro, Alexander; Albert, Todd J.; Weinstein, James N.

    2012-01-01

    Background: The Spine Patient Outcomes Research Trial (SPORT) is a prospective, multicenter study of operative versus nonoperative treatment of lumbar intervertebral disc herniation. It has been suggested that epidural steroid injections may help improve patient outcomes and lower the rate of crossover to surgical treatment. Methods: One hundred and fifty-four patients included in the intervertebral disc herniation arm of the SPORT who had received an epidural steroid injection during the first three months of the study and no injection prior to the study (the ESI group) were compared with 453 patients who had not received an injection during the first three months of the study or prior to the study (the No-ESI group). Results: There was a significant difference in the preference for surgery between groups (19% in the ESI group compared with 56% in the No-ESI group, p < 0.001). There was no difference in primary or secondary outcome measures at four years between the groups. A higher percentage of patients changed from surgical to nonsurgical treatment in the ESI group (41% versus 12% in the No-ESI, p < 0.001). Conclusions: Patients with lumbar disc herniation treated with epidural steroid injection had no improvement in short or long-term outcomes compared with patients who were not treated with epidural steroid injection. There was a higher prevalence of crossover to nonsurgical treatment among surgically assigned ESI-group patients, although this was confounded by the increased baseline desire to avoid surgery among patients in the ESI group. Given these data, we concluded that more studies are necessary to establish the value of epidural steroid injection for symptomatic lumbar intervertebral disc herniation. Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence. PMID:22739998

  14. Intradural lumbar disc herniations associated with epidural adhesion : report of two cases.

    PubMed

    Han, In-Ho; Kim, Keun-Su; Jin, Byung-Ho

    2009-08-01

    Intradural lumbar disc herniation (ILDH) is rare. In this report, authors present 2 cases of ILDHs associated with severe adhesion between the dural sac and posterior longitudinal ligament. In a 40-year-old man, ILDH occurred in association with epidural adhesion due to ossification of the posterior longitudinal ligament (OPLL). In other 31-year-old man, ILDH occurred in presence of epidural adhesion due to previous spine surgery. PMID:19763222

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

    NASA Astrophysics Data System (ADS)

    Zhang, Dianxue; Cheng, Hefu; Wang, Jindong

    2005-07-01

    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.

  16. Retrolisthesis and Lumbar Disc Herniation: A Pre-operative Assessment of Patient Function

    PubMed Central

    Shen, Michael; Razi, Afshin; Lurie, Jon D.; Hanscom, Brett; Weinstein, Jim

    2008-01-01

    BACKGROUND CONTEXT Retrolisthesis is relatively rare but when present has been associated with increased back pain and impaired back function. Neither the prevalence of this condition in individuals with lumbar disc herniations nor its possible relation to pre-operative back pain and dysfunction has been well studied. PURPOSE The purposes of this study were as follows: 1) to determine the prevalence of retrolisthesis (alone or in combination with other degenerative conditions) in individuals with confirmed L5 – S1 disc herniation who later underwent lumbar discectomy; 2) to determine if there is any association between retrolisthesis and degenerative changes within the same vertebral motion segment; and 3) to determine the relation between retrolisthesis (alone or in combination with other degenerative conditions) and pre-operative low back pain, physical function, and quality of life. STUDY DESIGN/SETTING Cross-sectional study. PATIENT SAMPLE A total of 125 individuals were identified for incorporation into this study. All patients had confirmed L5-S1 disc herniation on MRI and later underwent L5-S1 discectomy. All patients were enrolled in the SPORT (Spine Patient Outcomes Research Trial) study; data was obtained from the multi-institutional database comprised of SPORT patients from across the United States. OUTCOME MEASURES Retrolisthesis, Degenerative change on MRI, Modic Changes. METHODS MRI scans of the lumbar spine were assessed at spinal level L5–S1 for all 125 patients. Retrolisthesis was defined as posterior subluxation of 8% or more. Disc degeneration was defined as any loss of disc signal on T2 imaging. Modic changes were graded 1 – 3 and collectively classified as vertebral endplate degenerative changes. The presence of facet arthropathy and ligamentum flavum hypertrophy were classified jointly as posterior degenerative changes. RESULTS The overall incidence of retrolisthesis at L5-S1 in our study was 23.2%. Retrolisthesis combined with posterior degenerative changes, degenerative disc disease, or vertebral endplate changes had incidences of 4.8%, 16%, and 4.8% respectively. The prevalence of retrolisthesis did not vary by sex, age, race, smoking status, or education level when compared to individuals with normal sagittal alignment. However, individuals with retrolisthesis were more likely to be receiving worker compensation than those without retrolisthesis. Increased age was found to be associated with individuals having vertebral endplate degenerative changes (both alone and in conjunction with retrolisthesis) and degenerative disc disease. Individuals who had retrolisthesis with concomitant vertebral endplate degenerative changes were more often smokers and had no insurance. The presence of retrolisthesis was not associated with an increased incidence of having degenerative disc disease, posterior degenerative changes, or vertebral endplate changes. No statistical significance was found between the presence of retrolisthesis on the degree of patient pre-operative low back pain and physical function. Patients with degenerative disc disease were found to have increased leg pain compared to those patients without degenerative disc changes. CONCLUSIONS We found no significant relationship between retrolisthesis in patients with L5-S1 disc herniation and worse baseline pain or function. It is possible that the contribution of pain or dysfunction related to retrolisthesis was far overshadowed by the presence of symptoms due to the concomitant disc herniation. It remains to be seen whether retrolisthesis will affect outcome following discectomy in these patients. PMID:17630138

  17. Recurrent lumbar disc herniation: A prospective comparative study of three surgical management procedures

    PubMed Central

    El Shazly, Ayman A.; El Wardany, Mohammed A.; Morsi, Ahmad M.

    2013-01-01

    Context: The optimal surgical treatment of recurrent lumbar disc herniation is controversial. Aim: To compare prospectively the clinical outcomes of surgical treatment of recurrent lumbar disc herniation by three different methods; discectomy alone, discectomy with transforaminal lumbar interbody fusion (TLIF), and diecectomy with posterolateral fusion (PLF), regardless of the postoperative radiological findings. Study Design: This is a prospective, randomized, comparative study. Materials and Methods: This is a prospective, randomized, comparative study on 45 patients with first time recurrent lumbar disc herniation. Patients were evaluated clinically by using the criteria of the Japanese Orthopedic Association's evaluation system for low back pain syndrome (JOA score). The patients were classified into three groups: Group A; patients who had revision discectomy alone, group B; patients who had revision discectomy with TLIF, and group C; patients who had revision discectomy with PLF. The mean follow-up period was 37 (±7.85 STD) months. Results: The mean overall recovery rate was 87.2% (±19.26 STD) and the satisfactory rate was 88.9%. Comparison between the three groups showed no significant difference with regard to the mean total postoperative JOA score, recovery rate, and satisfactory rate. However, the postoperative low back pain was significantly higher in group A than that of group B and C. Two patients in group A required further revision surgery. The incidences of dural tear and postoperative neurological deficit were higher in group A. The intraoperative blood loss and length of operation were significantly less in group A. The total cost of the procedure was significantly different between the three groups, being least in group A and highest in group B. There was no significant difference between the three groups with regard to the length of postoperative hospital stay. Conclusion: Revision discectomy is effective in patients with recurrent lumbar disc herniation. Fusion with revision discectomy improves the postoperative low back pain, decreases the intraoperative risk of dural tear or neural damage and decreases the postoperative incidence of mechanical instability or re-recurrence. TLIF and PLF have comparable results when used with revision discectomy, but PLF has significantly less total cost than TLIF. PMID:24403956

  18. Intradural lumbar disc herniation after percutaneous endoscopic lumbar discectomy: case report.

    PubMed

    Tamaki, Yasuaki; Sakai, Toshinori; Miyagi, Ryo; Nakagawa, Takefumi; Shimakawa, Tateaki; Sairyo, Koichi; Chikawa, Takashi

    2015-09-01

    A 64-year-old man was referred to the authors with low-back pain (LBP) and right leg pain with a history of previously diagnosed lumbar disc herniation (LDH) at L4-5. He had undergone 2 percutaneous endoscopic lumbar discectomies (PELDs) for the herniation at another institution, and according to the surgical record of the second surgery, a dural tear occurred intraoperatively but was not repaired. Postoperative conservative treatments such as an epidural block and blood patch had not relieved his persistent LBP or right leg pain. Upon referral to the authors, MRI and myelography revealed an intradural LDH. The herniated mass was removed by durotomy, and posterior lumbar interbody fusion was performed. His symptoms were partially improved after surgery. Primary suture is technically difficult when a dural tear occurs during PELD. Therefore, close attention should be paid to avoiding such tears, and surgeons should increase their awareness of intradural LDH as a possible postoperative complication of PELD. PMID:26068274

  19. Changes in the Cross-Sectional Area of Multifidus and Psoas in Unilateral Sciatica Caused by Lumbar Disc Herniation

    PubMed Central

    Kim, Wook Ha; Lee, Sang-Ho

    2011-01-01

    Objective To quantitatively evaluate the asymmetry of the multifidus and psoas muscles in unilateral sciatica caused by lumbar disc herniation using magnetic resonance imaging (MRI). Methods Seventy-six patients who underwent open microdiscectomy for unilateral L5 radiculopathy caused by disc herniation at the L4-5 level were enrolled, of which 39 patients (51.3%) had a symptom duration of 1 month or less (group A), and 37 (48.7%) had a symptom duration of 3 months or more (group B). The cross-sectional areas (CSAs) of the multifidus and psoas muscles were measured at the mid-portion of the L4-5 disc level on axial MRI, and compared between the diseased and normal sides in each group. Results The mean symptom duration was 0.6±0.4 months and 5.4±2.7 months for groups A and B, respectively (p<0.001). There were no differences in the demographics between the 2 groups. There was a significant difference in the CSA of the multifidus muscle between the diseased and normal sides (p<0.01) in group B. In contrast, no significant multifidus muscle asymmetry was found in group A. The CSA of the psoas muscle was not affected by disc herniation in either group. Conclusion The CSA of the multifidus muscle was reduced by lumbar disc herniation when symptom duration was 3 months or more. PMID:22102949

  20. Nonmedical methods to relieve low back pain caused by lumbar disc herniation: a descriptive study in northeastern Turkey.

    PubMed

    Cilingir, Dilek; Hintistan, Sevilay; Yigitbas, Cagla; Nural, Nesrin

    2014-06-01

    Low back pain due to the effects of lumbar disc herniation is a common complaint of patients who often subsequently seek help from medical professionals. It is also a significant health problem which is quite difficult to treat. This descriptive study was conducted to determine nonmedical methods used by patients with lumbar disc herniation to relieve low back pain; the patients' intensity of low back pain when they were admitted to the hospital was also explored. Ninety-two patients with lumbar disc herniation participated in this study, which was carried out at a university hospital in northeastern Turkey. Data were collected using a patient information form and the visual analog scale (VAS). When the patients were admitted to hospital, their mean VAS score was 6.56 ± 2.45. The study results showed that as a first choice nearly all of the patients (94.6%) with lumbar disc herniation preferred consulting with their physicians before to obtain relief for low back pain. However, in addition to seeing their physician, more than one-half of these patients (57.6%) also used nonmedical methods. The primary nonmedical methods were hot/cold compresses, wrapping various substances on the back, and herbal preparations. An increase in pain was noted by 17.0% of patients after using nonmedical methods. Findings indicated that more than two-thirds of patients experienced either no change or an increase in pain after using nonmedical methods to find relief. PMID:24882024

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

    PubMed Central

    2014-01-01

    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. PMID:25694932

  2. Brain herniation

    MedlinePLUS

    ... herniation; Uncal herniation; Subfalcine herniation; Tonsillar herniation; Herniation - brain ... Brain herniation occurs when something inside the skull produces pressure that moves brain tissues. This is most ...

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

    PubMed Central

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

    2013-01-01

    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

  4. Prognostic Factors for Postsurgical Recovery of Deltoid Palsy due to Cervical Disc Herniations

    PubMed Central

    Chung, Jae-Yoon; Chang, Han; Song, Kyung-Jin; Kim, Jin-Hyok; Hong, Chang-Hwa; Lee, Jung Sub; Lee, Sang-Hun; Song, Kwang-Sup; Yang, Jae Jun; Uh, Jae-Hyung; Kim, Young-Tae; Lee, Jae Min

    2015-01-01

    Study Design Retrospective multicenter study. Purpose We aimed to investigate prognostic factors affecting postsurgical recovery of deltoid palsy due to cervical disc herniation (CDH). Overview of Literature Little information is available about prognostic factors affecting postsurgical recovery of deltoid palsy due to CDH. Methods Sixty-one patients with CDH causing deltoid palsy (less than grade 3) were included in this study: 35 soft discs and 26 hard discs. Average duration of preoperative deltoid palsy was 11.9 weeks. Thirty-two patients underwent single-level surgery, 22 two-level, four three-level, and three four-level. Patients with accompanying myelopathy, shoulder diseases, or peripheral neuropathy were excluded from the study. Results Deltoid palsy (2.4 grades vs. 4.5 grades, p<0.001) and radiculopathy (6.4 points vs. 2.1 points, p<0.001) significantly improved after surgery. Thirty-six of 61 patients (59%) achieved full recovery (grade 5) of deltoid palsy, with an average time of 8.4 weeks. Longer duration of preoperative deltoid palsy and more severe radiculopathy negatively affected the degree of improvement in deltoid palsy. Age, gender, number of surgery level, and disc type did not affect the degree of improvement of deltoid palsy. Contrary to our expectations, severity of preoperative deltoid palsy did not affect the degree of improvement. Due to the shorter duration of preoperative deltoid palsy, in the context of rapid referral, early surgical decompression resulted in significant recovery of more severe grades (grade 0 or 1) of deltoid palsy compared to grade 2 or 3 deltoid palsy. Conclusions Early surgical decompression significantly improved deltoid palsy caused by CDH, irrespective of age, gender, number of surgery level, and disc type. However, longer duration of deltoid palsy and more severe intensity of preoperative radiating pain were associated with less improvement of deltoid palsy postoperatively. PMID:26435786

  5. Magnetic Resonance Imaging Predictors of Surgical Outcome in Patients with Lumbar Intervertebral Disc Herniation

    PubMed Central

    Lurie, Jon D.; Moses, Rachel A.; Tosteson, Anna N. A.; Tosteson, Tor D.; Carragee, Eugene J.; Carrino, John A.; Kaiser, Jay A.; Herzog, Richard J.

    2013-01-01

    Study Design A retrospective cohort design Objective To determine if baseline MRI findings including central/foraminal stenosis, Modic change, disc morphology, facet arthropathy, disc degeneration, nerve root impingement, and thecal sac compression are associated with differential surgical treatment effect. Summary of Background Data Intervertebral Disc Herniation (IDH)remains the most common source of lumbar radiculopathy treated either with discectomy or non-operative intervention. Although MRI remains the reliable gold standard for diagnosis, uncertainty surrounds the relationship between MRI findings and treatment outcomes. Methods Three-hundred-and-seven “complete” images from patients enrolled in a previous trial were de-identified and evaluated by one of 4 independent readers. Findings were compared to outcome measures including the Oswestry Disability Index. Differences in surgery and non-operative treatment outcomes were evaluated between image characteristic subgroups and TE determined by the difference in ODI scores. Results The cohort was comprised of 40% females with an average age of 41.5 (±11.6), 61% of which underwent discectomy for IDH. Patients undergoing surgery with Modic type I endplate changes had worse outcomes (?26.4 versus ?39.7 for none and ?39.2 for type 2, p=0.002) and smaller treatment effect (?3.5 versus ?19.3 for none and ?15.7 for type 2, p=0.003). Those with compression >=1/3 showed the greatest improvement within the surgical group (?41.9 for >=1/3 versus ?31.6 for none and ?38.1 for <1/3,p=0.007), and the highest TE (?23 compared to ?11.7 for none and ?15.2 for <1/3, p=0.015). Furthermore, patients with minimal nerve root impingement demonstrated worse surgical outcomes(?26.5 versus ?41.1 for “displaced” and ?38.9 for “compressed”, p=0.016). Conclusion Among patients with IDH, those with thecal sac compression >=1/3 had greater surgical treatment effect than those with small disc herniations and Modic type I changes. Additionally, patients with nerve root “compression” and “displacement” benefit more from surgery than those with minimal nerve-root impingement. PMID:23429684

  6. Cervical myelopathy due to single level disc herniation presenting as intramedullary mass lesion: What to do first?

    PubMed

    Ek?i, Murat ?akir; Özcan Ek?i, Emel Ece; Y?lmaz, Baran; Tokta?, Zafer Orkun; Konya, Deniz

    2015-01-01

    Cervical myelopathy (CM) is mostly a degenerative process ending in myelopathic and/or radiculopathic syndromes. On T2-weighted magnetic resonance imaging (MRI), CM appears as a hyperintense area near the spondylotic spine. This high intensity signal depends on the impact of outer forces and their duration. It also determines the prognosis of the surgical candidate. A 40-year-old male patient admitted to our clinic with right upper extremity weakness and hypoesthesia that had started 2 months earlier. On neurological examination there was 2/5 motor weakness of right biceps brachii, and hypoesthesia over right C6 dermatome. Right upper extremity deep tendon reflexes were hypoactive, but lower ones were hyperactive. After clinical and radiological work-up, preliminary diagnosis was directed to a spinal intramedullary tumor. Total resection of the herniated cervical disc fragment and the mass lesion was managed. Pathology of the mass lesion was compatible with subacute infarct tissue and inflammatory response. Final diagnosis was CM under effect of cervical disc herniation. Contrast-enhanced spinal cord myelopathic lesions are very rare and resemble much more tumors and inflammatory processes. However, the principal treatment approach totally differs depending on pathology. When there are both a disc herniation and a high clinical suspicion; biopsy should be delayed. The most probable solution will be surgery for the disc disease with thorough preoperative scanning of vascular malformations; clinical and radiological close follow-up after surgery. Biopsy or surgical resection can be performed if patient deteriorates despite the primary surgery. PMID:25972718

  7. SPORT: Do outcomes vary across centers for surgery for lumbar disc herniation?

    PubMed Central

    Desai, Atman; Bekelis, Kimon; Ball, Perry A.; Lurie, Jon; Mirza, Sohail K.; Tosteson, Tor D.; Zhao, Wenyan; Weinstein, James N.

    2014-01-01

    Background Lumbar discectomy is the most common procedure performed in spine surgery. Different centers performing this procedure may have different outcomes. Objective To determine whether the choice of academic spine center in which surgery is performed affects outcome after lumbar discectomy. Methods Spine Patient Outcomes Research Trial (SPORT) cohort participants with a confirmed diagnosis of intervertebral disc herniation (IDH) undergoing standard first-time open discectomy were followed from baseline at 6 weeks, and 3, 6, 12 months and yearly thereafter, at 13 spine clinics in 11 US states. Patient data were retrospectively reviewed. As of August 2009, the mean (SD) follow-up among all analyzed IDH patients was 41.3 (14.6) months. The median (range) follow-up time among all analyzed IDH patients was 47.4 (1.3, 95.3) months. Enrollment began in March 2000 and ended in November 2004. Results 792 patients underwent first-time lumbar discectomy. Significant differences were found amongst centers with regard to patient age and race, and in baseline levels of disability and treatment preferences. There were no significant differences among the study centers in other patient characteristics (e.g., sex, body mass index, the prevalence of smoking, diabetes or hypertension), or disease characteristics (herniation level or type). Some short-term outcomes varied significantly among centers, including operative duration and blood loss, the incidence of durotomy and the length of hospital stay. Unadjusted reoperation rates also varied across centers. There were no differences among the various centers in incidence of nerve root injury, post-operative mortality, SF-36 scores of body pain or physical function, or Oswestry Disability Index at 4 years. Conclusions Although mean operative blood loss, risk of durotomy and length of hospital stay vary across academic centers performing lumbar discectomy, there appears to be no difference in long-term functional outcomes. The role of different reoperation rates in producing similar outcomes remains unclear. PMID:22791040

  8. One stage laminoplasty and posterior herniotomy for the treatment of myelopathy caused by cervical stenosis with cervical disc herniation

    PubMed Central

    Yue, Bin; Chen, Bohua; Ma, Xue-Xiao; Xi, Yong-Ming; Xiang, Hong-Fei; Hu, You-Gu; Zhang, Guoqing

    2015-01-01

    The aim of the study was to introduce a method of one stage laminoplasty and posterior herniotomy for myelopathy caused by cervical stenosis with cervical disc herniation and to evaluate the clinical efficacy of this surgery. From 1999 to 2008, 18 patients with myelopathy caused by cervical stenosis with cervical disc herniation who underwent this procedure were included. The average age was 63 years (range 48-74 years), and the average follow-up period was 46 months (range 3-108 months). Neurologic status was evaluated using the JOA scoring system. Neurological symptoms improvement was seen in all patients after surgery. The average JOA score was 14.22±1.86 by final follow-up, which was higher than preoperative values (P<0.01), and the average improvement in neurological function was 76.63%. Neurologic examination showed that excellent results had been obtained by 10 patients, good results by 8 patients, with no fair or poor results. 2 patients developed cerebrospinal fluid leakage after surgery and recovered during the follow-up period. One patient with cervical disc herniation developed postoperative C5 palsy on the axle side on the third day after surgery. She completely recovered by 1 month after surgery. No other patients experienced postoperative neurologic complications. Complete anterior and posterior decompression of the spinal cord was achieved after surgery. We concluded that one stage laminoplasty and posterior herniotomy is an effective, reliable, and safe procedure for the treatment of myelopathy caused by cervical stenosis with cervical disc herniation. PMID:26309625

  9. Characteristics of Lumbar Disc Herniation With Exacerbation of Presentation Due to Spinal Manipulative Therapy

    PubMed Central

    Huang, Sheng-Li; Liu, Yan-Xi; Yuan, Guo-Lian; Zhang, Ji; Yan, Hong-Wei

    2015-01-01

    Abstract The aim of this article was to delineate the characteristics of lumbar disc herniation (LDH) in patients with exacerbation of symptoms caused by spinal manipulative therapy (SMT). The main emphasis should be on the prevention of this condition by identifying relevant risk factors. Detailed clinico-radiological profiles of a total number of 10 LDH patients with exacerbation of presentation after SMT were reviewed. All the patients underwent neurological and magnetic resonance imaging examinations. Laminectomy and discectomy were performed, and follow-up was carried out in all patients. The duration of symptoms in the patients before SMT was 4–15 years. After the therapy, an acute exacerbation of back and radicular pain was observed within 24?h. Magnetic resonance imaging showed that L4–L5 was the most frequently affected level observed (7 patients), and each patient had a large disc fragment in the spinal canal. The disc fragments were classified into 3 types according to their localizations. The time internal between the exacerbation of presentation and surgery was 23.1 days. No perioperative complications were noted. All the patients were relieved of radicular pain a few days after surgery. During postoperative follow-up, all patients regained the ability to walk; one patient received catheterization for 1 month and another for 6 months. Eight patients reported a complete resolution of presentation and the rest 2 patients were significantly improved. SMT should be prohibited in some LDH patients to prevent neurological damages, in whom there are 5 possible risk factors. Surgical results for these patients are encouraging. PMID:25816037

  10. Percutaneous endoscopic lumbar discectomy for a huge herniated disc causing acute cauda equina syndrome: a case report.

    PubMed

    Jha, Subash C; Tonogai, Ichiro; Takata, Yoichiro; Sakai, Toshinori; Higashino, Kosaku; Matsuura, Tetsuya; Suzue, Naoto; Hamada, Daisuke; Goto, Tomohiro; Nishisho, Toshihiko; Tsutsui, Takahiko; Goda, Yuichiro; Abe, Mitsunobu; Mineta, Kazuaki; Kimura, Tetsuya; Nitta, Akihiro; Hama, Shingo; Higuchi, Tadahiro; Fukuta, Shoji; Sairyo, Koichi

    2015-01-01

    Microsurgery for lumbar disc herniation that requires surgical intervention has been well described. The methods vary from traditional open discectomy to minimally invasive techniques. All need adequate preanesthetic preparation of patients as general anesthesia is required for the procedure, and nerve monitoring is necessary to prevent iatrogenic nerve injury. Conventional surgical techniques sometimes require the removal of the corresponding lamina to assess the nerve root and herniated disc, and this may increase the risk for posterior instability of the vertebral body. Should this occur, fusion surgery may be needed, further increasing morbidity and cost. We present here a case of lumbar herniated disc fragments causing acute cauda equina syndrome that were endoscopically resected through a transforaminal approach in an awake patient under local anesthesia. Percutaneous endoscopic discectomy under local anesthesia proved to be a better alternative to open back surgery as it made immediate intervention possible, was associated with fewer perioperative complications and morbidity, minimized soft tissue damage, and allowed early rehabilitation with a better outcome and greater patient satisfaction. In addition to these advantages, percutaneous endoscopic discectomy protects other approaches that may be needed in subsequent surgeries, whether open or minimally invasive. PMID:25817294

  11. Comparison of Percutaneous Endoscopic Lumbar Discectomy and Open Lumbar Surgery for Adjacent Segment Degeneration and Recurrent Disc Herniation

    PubMed Central

    Chen, Huan-Chieh; Lee, Chih-Hsun; Wei, Li; Lui, Tai-Ngar; Lin, Tien-Jen

    2015-01-01

    Objective. The goal of the present study was to examine the clinical results of percutaneous endoscopic lumbar discectomy (PELD) and open lumbar surgery for patients with adjacent segment degeneration (ASD) and recurrence of disc herniation. Methods. From December 2011 to November 2013, we collected forty-three patients who underwent repeated lumbar surgery. These patients, either received PELD (18 patients) or repeated open lumbar surgery (25 patients), due to ASD or recurrence of disc herniation at L3-4, L4-5, or L5-S1 level, were assigned to different groups according to the surgical approaches. Clinical data were assessed and compared. Results. Mean blood loss was significantly less in the PELD group as compared to the open lumbar surgery group (P < 0.0001). Hospital stay and mean operating time were shorter significantly in the PELD group as compared to the open lumbar surgery group (P < 0.0001). Immediate postoperative pain improvement in VAS was 3.5 in the PELD group and ?0.56 in the open lumbar surgery group (P < 0.0001). Conclusion. For ASD and recurrent lumbar disc herniation, PELD had more advantages over open lumbar surgery in terms of reduced blood loss, shorter hospital stay, operating time, fewer complications, and less postoperative discomfort. PMID:25861474

  12. Prognostic factors for non-success in patients with sciatica and disc herniation

    PubMed Central

    2012-01-01

    Background Few studies have investigated prognostic factors for patients with sciatica, especially for patients treated without surgery. The aim of this study was to identify factors associated with non-success after 1 and 2?years of follow-up and to test the prognostic value of surgical treatment for sciatica. Methods The study was a prospective multicentre observational study including 466 patients with sciatica and lumbar disc herniation. Potential prognostic factors were sociodemographic characteristics, back pain history, kinesiophobia, emotional distress, pain, comorbidity and clinical examination findings. Study participation did not alter treatment considerations for the patients in the clinics. Patients reported on the questionnaires if surgery of the disc herniation had been performed. Uni- and multivariate logistic regression analyses were used to evaluate factors associated with non-success, defined as Maine–Seattle Back Questionnaire score of ?5 (0–12) (primary outcome) and Sciatica Bothersomeness Index ?7 (0–24) (secondary outcome). Results Rates of non-success were at 1 and 2?years 44% and 39% for the main outcome and 47% and 42% for the secondary outcome. Approximately 1/3 of the patients were treated surgically. For the main outcome variable, in the final multivariate model non-success at 1?year was significantly associated with being male (OR 1.70 [95% CI; 1.06???2.73]), smoker (2.06 [1.31???3.25]), more back pain (1.0 [1.01???1.02]), more comorbid subjective health complaints (1.09 [1.03???1.15]), reduced tendon reflex (1.62 [1.03???2.56]), and not treated surgically (2.97 [1.75???5.04]). Further, factors significantly associated with non-success at 2?years were duration of back problems?>;?1?year (1.92 [1.11???3.32]), duration of sciatica?>;?3?months (2.30 [1.40???3.80]), more comorbid subjective health complaints (1.10 [1.03???1.17]) and kinesiophobia (1.04 [1.00???1.08]). For the secondary outcome variable, in the final multivariate model, more comorbid subjective health complaints, more back pain, muscular weakness at clinical examination, and not treated surgically, were independent prognostic factors for non-success at both 1 and 2?years. Conclusions The results indicate that the prognosis for sciatica referred to secondary care is not that good and only slightly better after surgery and that comorbidity should be assessed in patients with sciatica. This calls for a broader assessment of patients with sciatica than the traditional clinical assessment in which mainly the physical symptoms and signs are investigated. PMID:22999108

  13. Preoperative predictors for the return to work of herniated disc patients.

    PubMed

    Kitze, K; Winkler, D; Günther, L; Angermeyer, M C

    2008-02-01

    This study assessed socio-demographic, physical, psychological, and work-related factors predicting the ability to work 6 months after operation in disc herniation patients. After nucleotomy 214 patients answered questionnaires on job satisfaction, their desire for a disability pension, preoperative sick leave, and completed the QLQ-C30, and SCL-27A questionnaires. Additionally, data on the severity of injury and duration of pain were extracted from the clinical reports. 182 patients answered the follow-up questionnaire 6 months after operation by telephone. Socio-demgraphic and psychological factors did not influence the return to work. Factors found to be related to the ability to work were job satisfaction, preoperative sick leave, pain, and the desire for a disability pension. Using multiple regression analysis, the ability to work 6 months after rehabilitation was predicted on the basis of job satisfaction, a preoperative sick leave of less than 6 weeks, and a low pain intensity preoperatively. The results are discussed with respect to their socioeconomic implications. PMID:18393159

  14. Estimates of success in patients with sciatica due to lumbar disc herniation depend upon outcome measure.

    PubMed

    Haugen, Anne Julsrud; Grøvle, Lars; Brox, Jens Ivar; Natvig, Bård; Keller, Anne; Soldal, Dag; Grotle, Margreth

    2011-10-01

    The objectives were to estimate the cut-off points for success on different sciatica outcome measures and to determine the success rate after an episode of sciatica by using these cut-offs. A 12-month multicenter observational study was conducted on 466 patients with sciatica and lumbar disc herniation. The cut-off values were estimated by ROC curve analyses using Completely recovered or Much better on a 7-point global change scale as external criterion for success. The cut-off values (references in brackets) at 12 months were leg pain VAS 17.5 (0-100), back pain VAS 22.5 (0-100), Sciatica Bothersomeness Index 6.5 (0-24), Maine-Seattle Back Questionnaire 4.5 (0-12), and the SF-36 subscales bodily pain 51.5, and physical functioning 81.7 (0-100, higher values indicate better health). In conclusion, the success rates at 12 months varied from 49 to 58% depending on the measure used. The proposed cut-offs may facilitate the comparison of success rates across studies. PMID:21516463

  15. A PHASED REHABILITATION PROTOCOL FOR ATHLETES WITH LUMBAR INTERVERTEBRAL DISC HERNIATION

    PubMed Central

    VanGelder, Leonard H.; Vaughn, Daniel W.

    2013-01-01

    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

  16. Imaging of Herniated Discs of the Cervical Spine: Inter-Modality Differences between 64-Slice Multidetector CT and 1.5-T MRI

    PubMed Central

    Yi, Ji Sook; Han, Jong Kyu; Kim, Hyun-Joo

    2015-01-01

    Objective To assess inter-modality variability when evaluating cervical intervertebral disc herniation using 64-slice multidetector-row computed tomography (MDCT) and magnetic resonance imaging (MRI). Materials and Methods Three musculoskeletal radiologists independently reviewed cervical spine 1.5-T MRI and 64-slice MDCT data on C2-3 though C6-7 of 51 patients in the context of intervertebral disc herniation. Interobserver and inter-modality agreements were expressed as unweighted kappa values. Weighted kappa statistics were used to assess the extents of agreement in terms of the number of involved segments (NIS) in disc herniation and epicenter measurements collected using MDCT and MRI. Results The interobserver agreement rates upon evaluation of disc morphology by the three radiologists were in fair to moderate agreement (k = 0.39-0.53 for MDCT images; k = 0.45-0.56 for MRIs). When the disc morphology was categorized into two and four grades, the inter-modality agreement rates were moderate (k-value, 0.59) and substantial (k-value, 0.66), respectively. The inter-modality agreements for evaluations of the NIS (k-value, 0.78) and the epicenter (k-value, 0.79) were substantial. Also, the interobserver agreements for the NIS (CT; k-value, 0.85 and MRI; k-value, 0.88) and epicenter (CT; k-value, 0.74 and MRI; k-value, 0.70) evaluations by two readers were substantial. MDCT tended to underestimate the extent of herniated disc lesions compared with MRI. Conclusion Multidetector-row computed tomography and MRI showed a moderate-to-substantial degree of inter-modality agreement for the assessment of herniated cervical discs. MDCT images have a tendency to underestimate the anterior/posterior extent of the herniated disc compared with MRI. PMID:26175589

  17. Outcome of surgical treatment of lumbar disc herniation in young individuals.

    PubMed

    Strömqvist, F; Strömqvist, B; Jönsson, B; Gerdhem, P; Karlsson, M K

    2015-12-01

    Lumbar disc herniation (LDH) is uncommon in youth and few cases are treated surgically. Very few outcome studies exist for LDH surgery in this age group. Our aim was to explore differences in gender in pre-operative level of disability and outcome of surgery for LDH in patients aged ? 20 years using prospectively collected data. From the national Swedish SweSpine register we identified 180 patients with one-year and 108 with two-year follow-up data ? 20 years of age, who between the years 2000 and 2010 had a primary operation for LDH. Both male and female patients reported pronounced impairment before the operation in all patient reported outcome measures, with female patients experiencing significantly greater back pain, having greater analgesic requirements and reporting significantly inferior scores in EuroQol (EQ-5D-index), EQ-visual analogue scale, most aspects of Short Form-36 and Oswestry Disabilities Index, when compared with male patients. Surgery conferred a statistically significant improvement in all registered parameters, with few gender discrepancies. Quality of life at one year following surgery normalised in both males and females and only eight patients (4.5%) were dissatisfied with the outcome. Virtually all parameters were stable between the one- and two-year follow-up examination. LDH surgery leads to normal health and a favourable outcome in both male and female patients aged 20 years or younger, who failed to recover after non-operative management. Cite this article: Bone Joint J 2015;97-B:1675-82. PMID:26637684

  18. Surgical management of recurrent lumbar disc herniation and the role of fusion.

    PubMed

    Dower, Ashraf; Chatterji, Robindro; Swart, Alexander; Winder, Mark J

    2016-01-01

    This systematic review was performed to evaluate the various operative management strategies for recurrent lumbar disc herniation (RLDH), including the efficacy of instrumented spinal fusion (ISF) at repeat discectomy, and whether the operative approach for repeat discectomy, minimally invasive (MID) or conventional open discectomy (CD), affected the outcomes. RLDH is one of the most common complications of lumbar discectomies. Whilst repeat discectomy is the standard procedure performed, the routine addition of ISF has been advocated to improve outcomes and prevent reherniation. A comprehensive search of the MEDLINE, EMBASE, CINAHL and Cochrane databases was performed. The measured outcomes included the rate of satisfactory clinical outcome, improvement in leg and back pain, Japanese Orthopaedic Association (JOA) recovery score, and complication rates. In total, 37 studies met our inclusion criteria, with 1483 patients. The rate of satisfactory outcomes was found to be statistically similar between the patients undergoing a discectomy with or without fusion (77.8% with ISF versus 79.5% without ISF; p=0.665). Back pain and JOA scores showed greater improvements in the patients undergoing discectomy and fusion, compared to discectomy alone. The rate of satisfactory outcomes was marginally higher in the patients undergoing MID compared to CD (MID 81.2% versus CD 77.5%; p=0.248). However, the leg pain improvement was similar. The postoperative back pain improvement was greater in the MID group (52.5% MID versus 36.3% CD), but with lower complication rates, specifically durotomies (MID 5.2% versus CD 15.3%; p<0.001). There is no evidence to recommend the routine addition of ISF in the management of RLDH. The data suggest that MID has lower complication rates than CD in the setting of RLDH, yet unequivocal evidence is lacking. PMID:26282154

  19. Correlative analyses of isolated upper lumbar disc herniation and adjacent wedge-shaped vertebrae

    PubMed Central

    Xu, Jia-Xin; Yang, Si-Dong; Wang, Bao-Lin; Yang, Da-Long; Ding, Wen-Yuan; Shen, Yong

    2015-01-01

    Background: Upper lumbar disc herniation (ULDH) is easy to be misdiagnosed due to its special anatomical and atypical clinical features. Few studies have identified the relationship between ULDH and adjacent wedge-shaped vertebrae (WSV). Hypothesis: WSV may have some indicative relations withULDH. Patients and methods: Between January 2003 and October 2013, 47 patients (27 males and 20 females; mean age, 41.2 years) with single-level ULDH (as study group) and 47 sex- and age-matched healthy volunteers (as control group) were studied by radiograph. The two groups were compared with respect to age, sexual proportion, body mass index (BMI), kyphotic angle, and the proportion of WSV. Also, correlative analyses were conducted in the study group to investigate the relation between the kyphotic angle of target vertebrae and other factors including age, BMI, Cobb angle, JOA score and bone mineral density (BMD). Results: The average kyphotic angle in the study group was 11° (4°-22°), while the average kyphotic angle in the control group was 2° (0°-7°). Obviously, the mean kyphotic angle in the study group was statistically larger than that in the control group (t=13.797, P<0.001). The proportion of WSV in the study group was significantly larger than that in the control group (x2=36.380, P<0.0001). The correlations between kyphotic angles and other items (i.e., age, BMI, BMD, Cobb angle and JOA score) in the study group and the control group were low or uncorrelated. Conclusions: WSV are indicatively associated with adjacent ULDH. Thus, ULDH should be alerted when WSV are first found in radiograph and accompanied by clinical symptoms. PMID:25785106

  20. Effectiveness of heat-sensitive moxibustion in the treatment of lumbar disc herniation: study protocol for a randomized controlled trial

    PubMed Central

    2011-01-01

    Background Lumbar disc herniation is a common and costly problem. Moxibustion is employed to relieve symptoms and might therefore act as a therapeutic alternative. Many studies have already reported encouraging results in heat-sensitive moxibustion for lumbar disc herniation. Hence, we designed a randomized controlled clinical trial to investigate the effectiveness of heat-sensitive moxibustion compared with conventional moxibustion. Methods This trial is a multicenter, prospective, randomized controlled clinical trial. The 316 eligible patients are randomly allocated to two different groups. The experimental group is treated with heat-sensitive moxibustion (n = 158); while the control group (n = 158) is treated with conventional moxibustion. The moxibustion locations are different for the groups. The experimental group selects heat-sensitization acupoints from the region which consists of bilateral Da Changshu (BL25) and Yao Shu (Du2). Meanwhile, fixed acupoints are used in control group; patients in both groups receive 18 sessions in 2 weeks. Discussion The study design guarantees a high internal validity for the results. It is one large-scale randomized controlled trial to evaluate the efficacy of heat-sensitive moxibustion compared to conventional moxibustion and may provide evidence for this therapy as a treatment for moderate and severe lumbar disc herniation. Moreover, the result may uncover the inherent laws to improve the therapeutic effect with suspended moxibustion. Trial Registration The trial is registered at Chinese Clinical Trials Registry: ChiCTR-TRC-09000604. The application date was 27 November 2009. The first patient was randomized on the 16 June 2011. PMID:21995679

  1. Herniated disk

    MedlinePLUS

    ... back to all of your activities without having pain or straining your back. People who work in jobs that involve heavy lifting ... a review of the evidence for an American Pain Society clinical practice ... of symptomatic lumbar disc herniations. Orthop Clin North ...

  2. 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

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

    2014-01-01

    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. PMID:25566478

  3. Cost-effectiveness of microendoscopic discectomy versus conventional open discectomy in the treatment of lumbar disc herniation: a prospective randomised controlled trial [ISRCTN51857546

    PubMed Central

    Arts, Mark P; Peul, Wilco C; Brand, Ronald; Koes, Bart W; Thomeer, Ralph TWM

    2006-01-01

    Background Open discectomy is the standard surgical procedure in the treatment of patients with long-lasting sciatica caused by lumbar disc herniation. Minimally invasive approaches such as microendoscopic discectomy have gained attention in recent years. Reduced tissue trauma allows early ambulation, short hospital stay and quick resumption of daily activities. A comparative cost-effectiveness study has not been performed yet. We present the design of a randomised controlled trial on cost-effectiveness of microendoscopic discectomy versus conventional open discectomy in patients with lumbar disc herniation. Methods/Design Patients (age 18–70 years) presenting with sciatica due to lumbar disc herniation lasting more than 6–8 weeks are included. Patients with disc herniation larger than 1/3 of the spinal canal diameter, or disc herniation less than 1/3 of the spinal canal diameter with concomitant lateral recess stenosis or sequestration, are eliglible for participation. Randomisation into microendoscopic discectomy or conventional unilateral transflaval discectomy will take place in the operating room after induction of anesthesia. The length of skin incision is equal in both groups. The primary outcome measure is the functional assessment of the patient, measured by the Roland Disability Questionnaire for Sciatica, at 8 weeks and 1 year after surgery. We will also evaluate several other outcome parameters, including perceived recovery, leg and back pain, incidence of re-operations, complications, serum creatine kinase, quality of life, medical consumption, absenteeism and costs. The study is a randomised prospective multi-institutional trial, in which two surgical techniques are compared in a parallel group design. Patients and research nurses are kept blinded of the allocated treatment during the follow-up period of 2 years. Discussion Currently, open discectomy is the golden standard in the surgical treatment of lumbar disc herniation. Whether microendoscopic discectomy is more cost-effective than unilateral transflaval discectomy has to be determined by this trial. PMID:16696861

  4. Mini-open transthoracic approach for resection of a calcified herniated thoracic disc and repair of the dural surface with fibrin glue: a case report.

    PubMed

    Yoshioka, Katsuhito; Murakami, Hideki; Demura, Satoru; Kato, Satoshi; Tsuchiya, Hiroyuki

    2015-08-01

    This study reports a case of severe anterior compression of the spinal cord by a calcified herniated thoracic disc at the T9/10 level in a 46-year-old woman. She underwent resection of the calcified herniated thoracic disc and the integrated dura, using a microscopically assisted mini-open transthoracic approach. The remaining dura mater was shaped and repaired by alternate overlapping without suture. The dural surface was reinforced with a combination of fibrin glue and a polyglycolic acid sheet. This novel procedure prevented postoperative cerebrospinal fluid leakage. The patient made an excellent recovery, without any complications. PMID:26321561

  5. A comparison of angled sagittal MRI and conventional MRI in the diagnosis of herniated disc and stenosis in the cervical foramen

    PubMed Central

    Shim, Jung Hyun; Lee, Ju Hyun; Choi, Jin Wook; Lee, Dong Chan; Kim, Dong Hyun; Kim, Jae Keon; Hwang, Jang Hoe

    2009-01-01

    The object of this study is to demonstrate that angled sagittal magnetic resonance imaging (MRI) enables the precise diagnosis of herniated disc and stenosis in the cervical foramen, which is not available with conventional MRI. Due to both the anatomic features of the cervical foramen and the limitations of conventional MR techniques, it has been difficult to identify disease in the lateral aspects of the spinal canal and foramen using only conventional MRI. Angled sagittal MRI oriented perpendicular to the true course of the foramina facilitates the identification of the lateral disease. A review of 43 patients, who underwent anterior cervical discectomy and interbody fusion, is presented with a herniated disc and/or stenosis in the cervical foramen. They all had undergone conventional MRI and angled sagittal MRI. Fifty levels were surgically explored for evidence of foraminal herniated disc and stenosis. The results of each test were correlated with what was found at each explored surgical level. The sensitivity, specificity, and accuracy of both examinations for making the diagnosis of foraminal herniated disc and stenosis were compared. During the diagnosis of foraminal herniated disc, the sensitivity, specificity, and accuracy of angled sagittal MRI were 96.7, 95.0, and 96.0%, respectively, compared with 56.7, 85.0, and 68.0% for conventional MRI. In making the diagnosis of foraminal stenosis, the sensitivity, specificity, and accuracy of angled sagittal MRI were 96.3, 95.7, and 96.0%, respectively, compared with 40.7, 91.3, and 66.0% for conventional MRI. In the above groups, the difference between the tests for making the diagnosis of both foraminal herniated disc and stenosis was found to be statistically significant in sensitivity and accuracy. Angled sagittal MRI was a more accurate test compared to conventional MRI for making the diagnosis of herniated disc and stenosis in the cervical foramen. It can be utilized for the precise diagnosis of foraminal herniated disc and stenosis difficult or ambiguous in conventional MRI. PMID:19294432

  6. A new technique for the treatment of lumbar far lateral disc herniation: technical note and preliminary results.

    PubMed

    Greiner-Perth, R; Böhm, H; Allam, Y

    2003-06-01

    A newly designed technique for a minimally invasive approach to the laterally herniated disc is presented. Fifteen patients suffering from far lateral disc herniation (extraforaminal) were operated according to this technique. Through a small skin incision (1.5 cm), the paraspinal muscles are spread by dilators, until a working channel of 9 mm inner diameter and 11 mm outer diameter can be placed. The next steps are done through this channel using the surgical microscope. No bone resections are necessary and the facet joints are left untouched. However, partial resection of the intertransverse ligament may be necessary. The mean follow-up period for these 15 patients was 11.5 months, and they were evaluated by using the visual analogue scale (VAS) and the Oswestry Disability Index (ODI). The average surgical time was 43 min. The ODI improved from 30.6 (preoperative) to 14.3 (postoperative). The VAS of leg pain improved from 7 (preoperative) to 3.6 (postoperative), which represented a statistically significant improvement at the significance level of (P<0.01). No intra-operative or early postoperative complications occurred. However, one recurrence did occur, which was treated by the same technique. This technique combines the advantages of three-dimensional visual control (operating microscope) with the minimal surgical trauma of endoscopic techniques, while avoiding some of the shortcomings of both the microsurgical and endoscopic techniques. PMID:12800006

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

    PubMed

    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

    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

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

    SciTech Connect

    Liu Wengui; Wu Xiaotao; Guo Jinhe; Zhuang Suyang; Teng Gaojun

    2010-08-15

    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.

  9. Safety of carboxymethylcellulose/polyethylene oxide for the prevention of adhesions in lumbar disc herniation – consecutive case series review

    PubMed Central

    Fransen, Patrick

    2008-01-01

    Background Epidural fibrosis is regarded as a cause of failed back surgery syndrome (FBSS) when excessive adhesional/fibrotic scar tissue causes compression, pain or discomfort by tethering of nerve tissue to the surrounding muscle or bone. Fibrosis inhibitors could therefore increase the success rate of spinal surgery and decrease the need for reoperations. In recent years, bio-resorbable gels or films for the prevention of peridural fibrosis and post-operative adhesions have been developed that look clinically promising. This included a 100% synthetic, sterile, absorbable gel combinations of carboxymethylcellulose (CMC) and polyethylene oxide (PEO) used to coat the dura to reduce scarring after discectomy which became available in Europe in 2002. However, given the burden of the problem and unfavorable experience with other types of adhesion-reduction agents, our unit decided to evaluate the safety of CMC/PEO in a large population of patients undergoing spinal microdiscectomy for herniation. Methods To determine the safety and assess efficacy of carboxymethylcellulose/polyethylene oxide (CMC/PEO) gel as an anti-adhesion gel, a consecutive series of 396 patients undergoing lumbar discectomy performed by one surgeon had CMC/PEO gel administered at the end of surgery. The patients were followed up in accordance with standard clinical practice and records reviewed for side effects, such as skin reactions, general reactions or local fluid collections. Reoperations for recurrent herniation included an evaluation of fibrosis reduction. Results No product related complications were observed. Five patients needed reoperations for recurrent herniation. Significant but subjective reduction in fibrosis was observed in these patients. Conclusion The findings provide confidence that CMC/PEO gel is well tolerated as an agent to achieve reduction of fibrosis in lumbar disc surgery. Further formal prospective study is recommended in this area of unmet need. PMID:18513413

  10. Recurrent Lumbar Disc Herniation: Results of Revision Surgery and Assessment of Factors that May Affect the Outcome. A Non-Concurrent Prospective Study

    PubMed Central

    Arockiaraj, Justin; Amritanand, Rohit; Venkatesh, Krishnan; David, Kenny Samuel

    2015-01-01

    Study Design Non-concurrent prospective study. Purpose To determine the functional outcome after open 'fragment' discectomy for recurrent lumbar disc herniation, and to analyze the factors that may affect the outcome. Overview of Literature Literature search revealed only four studies where the factors affecting the outcome of a revision surgery for recurrent disc herniation have been evaluated. None of these studies analyzed for diabetes, disc degeneration and facet arthropathy. We have analyzed these features, in addition to the demographic and clinical factors. Methods Thirty-four patients who underwent the procedure were followed up for an average period of 27.1 months. The Japanese Orthopaedic Association (JOA) score and Oswestry disability index (ODI) were used to assess the functional outcome. Age, gender, smoking, diabetic status, duration of recurrent symptoms, the side of leg pain, level and type of disc herniation, degree of disc degeneration on magnetic resonance imaging, and facet joint arthritis before first and second surgeries, were analyzed as factors affecting the outcome. Results The average Hirabayashi improvement in JOA was 56.4%. The mean preoperative ODI was 74.5% and the mean ODI at final follow-up was 32.2%, the difference being statistically significant (p<0.01). Patients with diabetes, all of whom had poor long term glycemic control, were found to have a poor outcome in terms of ODI improvement (p=0.03). Conclusions Open fragment discectomy is a safe and effective surgical technique for the treatment of recurrent disc herniation. However, patients with uncontrolled diabetes may have a less favorable outcome. PMID:26435791

  11. Can clinical and radiological findings predict surgery for lumbar disc herniation? A systematic literature review

    PubMed Central

    White, Andrew P.; Harrop, James; Dettori, Joseph R.

    2012-01-01

    Study design:?Systematic review. Objective or clinical question:?What clinical and radiological findings in patients with lumbar-herniated nucleus pulposus can serve as predictors of surgical intervention? Methods:?Articles published between January 1975 and August 2011 were systematically reviewed using Pubmed, Cochrane, National Guideline Clearinghouse Databases, and bibliographies of key articles. Each article was subject to quality rating and was analyzed by two independent reviewers. Results:?From 123 citations, 21 underwent full-text review. Four studies met inclusion criteria. Only baseline disability as measured by the Roland Disability Index (RDI) or the Oswestry Disability Index (ODI) was consistently associated with a greater likelihood of having discectomy surgery across multiple studies. With the current literature, we were not able to find an association between surgery and several characteristics including smoking status, body mass index, neurological deficit, positive straight leg testing, and level of herniation. Conclusions:?From the limited data available, it appears that individual radiographic and clinical features are not able to predict the likelihood of surgical intervention. Higher baseline disability measurements (Oswestry and Roland) did correlate, however, with surgical treatment. PMID:23236305

  12. Evaluation of the Clinical Curative Effect of an O2-O3 mixture to Treat Lumbar Disc Herniation with Different Treatment Sessions

    PubMed Central

    Xu, L.; Li, Z-L.; He, X-F.; Xiang, D-C.; Ma, J.; Hong, C-J.; He, J-X.; Yang, L.; Gong, Z-H.; Qiu, J.

    2009-01-01

    Summary To compare the effective rates among one week, two week and four week treatment sessions of ozone therapy for lumbar disc herniation to provide a foundation for clinical decision-making. One hundred and eighty-seven lumbar disc herniation patients were divided into three groups, 103 cases for one week, 61 cases for two week and 23 cases for four week treatment sessions. The clinical curative effective rates in the three groups were 82.52%, 85.24% and 95.65% respectively. The effective rate among the three groups showed no significant difference at statistical analysis. Considering the cost-effectiveness of ozone therapy, increasing the treatment course does not enhance the curative effect. PMID:20465893

  13. Composite Features for Automatic Diagnosis of Intervertebral Disc Herniation from Lumbar MRI

    E-print Network

    Chaudhary, Vipin

    of the spinal column that provide body flexi- bility. Discs in the lumbar spine (lower-back) are composed the spinal canal due to Subarna Ghosh, Raja' S. Alomari and Vipin Chaudhary are affiliated to the Department

  14. Trends in inpatient setting laminectomy for excision of herniated intervertebral disc: Population-based estimates from the US nationwide inpatient sample

    PubMed Central

    Walcott, Brian P.; Hanak, Brian W.; Caracci, James R.; Redjal, Navid; Nahed, Brian V.; Kahle, Kristopher T.; Coumans, Jean-Valery C.E.

    2011-01-01

    Background: Herniated intervertebral discs can result in pain and neurological compromise. Treatment for this condition is categorized as surgical or non-surgical. We sought to identify trends in inpatient surgical management of herniated intervertebral discs using a national database. Methods: Patient discharges identified with a principal procedure relating to laminectomy for excision of herniated intervertebral disc were selected from the Nationwide Inpatient Sample (Healthcare Cost and Utilization Project - Agency for Healthcare Research and Quality, Rockville, MD), under the auspices of a data user agreement. These surgical patients did not undergo instrumented fusion. To account for the Nationwide Inpatient Sample weighting schema, design-adjusted analyses were used. The estimates of standard errors were calculated using SUDAAN software (Research Triangle International, NC, USA). This software is based on the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM); a uniform and standardized coding system. Results: Using International Classification of Disease 9th Revision clinical modifier (ICD-9 CM) procedure code 80.51, we were able to identify disc excision, in part or whole, by laminotomy or hemilaminectomy. The incidence of laminectomy for the excision of herniated intervertebral disc has decreased dramatically from 1993 where 266,152 cases were reported [CI = 22,342]. In 2007, only 123,398 cases were identified [CI = 12,438]. The average length of stay in 1993 was 4 days [CI = 0.17], and in 2007 it decreased to just 2 days [CI = 0.17]. Both these comparisons were significantly different at P < 0.001. The average inflation adjusted (2007 buying power) charge of the procedure in 1993 was 14,790.87 USD [CI = 916.85]. This value rose in 2007 to 24,639 USD [CI = 1,485.51]. This difference was significant at P < 0.001. Conclusions: National estimates indicate that the incidence of inpatient laminectomy for the excision of herniated intervertebral disc has decreased significantly. This trend is multifactorial and is likely related to developments in outcomes research, the growing popularity of alternative procedures (intervertebral instrumented fusion), and transition to an ambulatory setting of surgical care. PMID:21297929

  15. Integrative TCM Conservative Therapy for Low Back Pain due to Lumbar Disc Herniation: A Randomized Controlled Clinical Trial

    PubMed Central

    Yuan, Wei An; Huang, Shi Rong; Guo, Kai; Sun, Wu Quan; Xi, Xiao Bing; Zhang, Ming Cai; Kong, Ling Jun; Lu, Hua; Zhan, Hong Sheng; Cheng, Ying Wu

    2013-01-01

    Low back pain due to lumbar disc herniation (LDH) is very common in clinic. This randomized controlled trial was designed to investigate the effects of integrative TCM conservative therapy for low back pain due to LDH. A total of 408 patients with low back pain due to LDH were randomly assigned to an experimental group with integrative TCM therapy and a control group with normal conservative treatment by the ratio of 3?:?1. The primary outcome was the pain by the visual analogue scale (VAS). The secondary outcome was the low back functional activities by Chinese Short Form Oswestry Disability Index (C-SFODI). Immediately after treatment, patients in the experimental group experienced significant improvements in VAS and C-SFODI compared with the control group (between-group difference in mean change from baseline, ?16.62 points, P < 0.001 in VAS; ?15.55 points, P < 0.001 in C-SFODI). The difference remained at one-month followup, but it is only significant in C-SFODI at six-month followup (?7.68 points, P < 0.001). No serious adverse events were observed. These findings suggest that integrative TCM therapy may be a beneficial complementary and alternative therapy for patients with low back pain due to LDH. PMID:23864883

  16. Assessing the Effect of Spaceflight on the Propensity for Astronauts to Develop Disc Herniation

    NASA Technical Reports Server (NTRS)

    Feiveson, A.; Mendez, C.; Somers, J.

    2015-01-01

    A previous study 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 HNPs occurred well into astronauts' careers or in somecases 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. In addition, when an HNP occurs after spaceflight, is it related to previous spaceflight exposure? The purpose of this study was to investigate whether multiple missions, sex, age, vehicle landing dynamics, and flight duration affect the risk of developing an HNP usinga competing risks model. The outcome of the study will inform the Human System Risk Board assessment of back pain, inform the risk of injury due to dynamic loads, and update the previous dataset, which contained events up to December 31, 2006.

  17. Factors Predicting Patient Dissatisfaction 2 Years After Discectomy for Lumbar Disc Herniation in a Chinese Older Cohort

    PubMed Central

    Wang, Hui; Zhang, Di; Ma, Lei; Shen, Yong; Ding, Wenyuan

    2015-01-01

    Abstract We aim to identify factors predicting patient dissatisfaction 2 years after discectomy for lumbar disc herniation (LDH) in a Chinese older cohort. Preoperative and 2-year follow-up data for 843 patients were analyzed. After 2 years of discectomy, the patients rated their satisfaction by Patient Satisfaction Index (PSI), with response of 1 or 2 defining satisfaction and a PSI response of 3 or 4 defining dissatisfaction. Associations between perioperative variables and satisfaction with the results of surgery were examined in univariate and multivariate analysis. Six hundred fifty-seven patients had a PSI of 1 or 2 and were enrolled as satisfied group, 186 patients had a PSI of 3 or 4 and were enrolled as dissatisfied group. At baseline, no significant differences were found between the 2 groups in age, occupation, Oswestry Disability Index (ODI), Visual Analog Scale (VAS)-leg, and VAS-back. Compared to satisfied group, dissatisfied group had a significantly higher BMI and a higher incidence of depression. Two years after discectomy, no significant differences were found between the 2 groups in decrease of ODI, decrease of VAS-back, decrease of VAS-leg, surgery complications. Compared to satisfied group, dissatisfied group experienced higher incidence of symptom recurrence and depression. Logistic regression analysis showed that obesity, pre- and postoperative depression, symptom recurrence were independently associated with patient dissatisfaction 2 years after discectomy. In conclusion, more than 70% patients expressed satisfaction with discectomy for LDH. Two factors could predict patient dissatisfaction and be assessed before surgery: obesity and preoperative depression. Symptom recurrence and postoperative depression are also associated with diminished patient satisfaction. PMID:26448005

  18. Outcomes of Microendoscopic Discectomy and Percutaneous Transforaminal Endoscopic Discectomy for the Treatment of Lumbar Disc Herniation: A Comparative Retrospective Study

    PubMed Central

    Sinkemani, Arjun; Hong, Xin; Gao, Zeng-Xin; Zhuang, Su-Yang; Jiang, Zan-Li; Zhang, Shao-Dong; Bao, Jun-Ping; Zhu, Lei; Zhang, Pei; Xie, Xin-Hui; Wang, Feng

    2015-01-01

    Study Design Retrospective, case control evaluation of 86 patients who underwent microendoscopic discectomy (MED) and percutaneous transforaminal endoscopic discectomy (PTED) for the treatment of lumbar disc herniation (LDH). Purpose To evaluate the safety and the outcomes of MED and PTED for the treatment of LDH. Overview of Literature MED and PTED are minimally invasive surgical techniques for lower back pain. Studies to date have shown that MED and PTED are safe and effective treatment modalities for LDH. Methods A retrospective study was performed in patients with LDH treated with MED (n=50) and transforaminal endoscopic discectomy (PTED; n=36) in our hospital. All patients were followed-up with self-evaluation questionnaires, Oswestry disability index (ODI), medical outcomes study 36-item short form health survey and MacNab criteria. All the patients in both groups were followed up to 12 months after the operation. Results ODI questionnaire responses were not statistically different between the MED and PTED groups (53.00 vs. 48.72) before treatment. Average scores and minimal disability after 5 days to 12 months of follow-up were 4.96 in the MED group and 3.61 in the PTED group. According to MacNab criteria, 92.0% of the MED group and 94.4% of the PTED group had excellent or good results with no significant difference. Conclusions There was no significant difference between MED and PTED outcomes. Further large-scale, randomized studies with long-term follow-up are needed. PMID:26713113

  19. The Factors Associated With the Successful Outcomes of Percutaneous Disc Decompression in Patients With Lumbar Herniated Nucleus Pulposus

    PubMed Central

    Lee, Sang Heon; Kim, Nack Hwan; Park, Hyeun Jun; Yoo, Hyun-Joon; Jo, Soo Yung

    2015-01-01

    Objective To determine clinical and radiological factors that predict the successful outcome of percutaneous disc decompression (PDD) in patients with lumbar herniated nucleus pulposus (HNP). Methods We retrospectively reviewed the clinical and radiological features of patients who underwent lumbar PDD from April 2009 to March 2013. Sixty-nine patients with lumbar HNP were studied. Clinical outcome was assessed by the visual analogue scale (VAS) and the Oswestry Disability Index (ODI). Multivariate logistic regression analysis was performed to assess relationship among clinical and radiological factors and the successful outcome of the PDD. Results The VAS and the ODI decreased significantly at 1 year follow-up (p<0.01). One year after PDD, the reduction of the VAS (?VAS) was significantly greater in the patients with pain for <6 months (p=0.03) and subarticular HNP (p=0.015). The reduction of the ODI (?ODI) was significantly greater in the patients with high intensity zone (p=0.04). Multivariate logistic regression analysis revealed the following 5 factors that were associated with the successful outcome after PDD: pain duration for <6 months (odds ratio [OR]=14.036; p=0.006), positive straight leg raising test (OR=8.425, p=0.014), the extruded HNP (OR=0.106, p=0.04), the sequestrated HNP (OR=0.037, p=0.026), and the subarticular HNP (OR=10.876, p=0.012). Conclusion PDD provided significant improvement of pain and disability of patients. The results of the analysis indicated that the duration of pain <6 months, positive straight leg raising test, the subarticular HNP, and the protruded HNP were predicting factors associated with the successful response of PDD in patients with lumbar HNP. PMID:26605171

  20. The Impact of Workers' Compensation on Outcomes of Surgical and Nonoperative Therapy for Patients with a Lumbar Disc Herniation SPORT

    PubMed Central

    Atlas, Steven J.; Tosteson, Tor D.; Blood, Emily A.; Skinner, Jonathan S.; Pransky, Glenn S.; Weinstein, James N.

    2010-01-01

    Study Design Prospective randomized and observational cohorts. Objective To compare outcomes of patients with and without workers' compensation who had surgical and nonoperative treatment for a lumbar intervertebral disc herniation (IDH). Summary of Background Data Few studies have examined the association between worker's compensation and outcomes of surgical and nonoperative treatment. Methods Patients with at least 6 weeks of sciatica and a lumbar IDH were enrolled in either a randomized trial or observational cohort at 13 US spine centers. Patients were categorized as workers' compensation or nonworkers' compensation based on baseline disability compensation and work status. Treatment was usual nonoperative care or surgical discectomy. Outcomes included pain, functional impairment, satisfaction and work/disability status at 6 weeks, 3, 6, 12, and 24 months. Results Combining randomized and observational cohorts, 113 patients with workers' compensation and 811 patients without were followed for 2 years. There were significant improvements in pain, function, and satisfaction with both surgical and nonoperative treatment in both groups. In the nonworkers' compensation group, there was a clinically and statistically significant advantage for surgery at 3 months that remained significant at 2 years. However, in the workers' compensation group, the benefit of surgery diminished with time; at 2 years no significant advantage was seen for surgery in any outcome (treatment difference for SF-36 bodily pain [?5.9; 95% CI: ?16.7–4.9] and physical function [5.0; 95% CI: ?4.9–15]). Surgical treatment was not associated with better work or disability outcomes in either group. Conclusion Patients with a lumbar IDH improved substantially with both surgical and nonoperative treatment. However, there was no added benefit associated with surgical treatment for patients with workers' compensation at 2 years while those in the nonworkers' compensation group had significantly greater improvement with surgical treatment. PMID:20023603

  1. Lumbar periradicular abscess mimicking a fragmented lumbar disc herniation : an unusual case.

    PubMed

    Bakar, Bulent; Tekkok, Ismail Hakki

    2008-12-01

    We herein describe the case of a focal spontaneous spinal epidural abscess who was initially diagnosed to have a free fragment of a lumbar disc. A 71-year-old woman presented with history of low back and right leg pain. Magnetic resonance imaging suggested a peripherally enhancing free fragment extending down from S1 nerve root axilla. Preoperative laboratory investigation showed elevation of c-reactive protein (CRP), erythrocyte sedimentation rate (ESR) levels. She was taken for surgery and a fluctuating mass at the axilla of S1 nerve was found. When the mass was probed with a dissector, a dark yellow, thick pus drained out. Pus cultures were negative. Patients who present with extreme low back plus leg pain and increased leucocyte count, ESR and CRP levels should raise the suspicion of an infection of a vertebral body or spinal epidural space. PMID:19137084

  2. Changes in the Expressions of Iba1 and Calcitonin Gene-Related Peptide in Adjacent Lumbar Spinal Segments after Lumbar Disc Herniation in a Rat Model

    PubMed Central

    2015-01-01

    Lumbar disc herniation is commonly encountered in clinical practice and can induce sciatica due to mechanical and/or chemical irritation and the release of proinflammatory cytokines. However, symptoms are not confined to the affected spinal cord segment. The purpose of this study was to determine whether multisegmental molecular changes exist between adjacent lumbar spinal segments using a rat model of lumbar disc herniation. Twenty-nine male Sprague-Dawley rats were randomly assigned to either a sham-operated group (n=10) or a nucleus pulposus (NP)-exposed group (n=19). Rats in the NP-exposed group were further subdivided into a significant pain subgroup (n=12) and a no significant pain subgroup (n=7) using mechanical pain thresholds determined von Frey filaments. Immunohistochemical stainings of microglia (ionized calcium-binding adapter molecule 1; Iba1), astrocytes (glial fibrillary acidic protein; GFAP), calcitonin gene-related peptide (CGRP), and transient receptor potential vanilloid 1 (TRPV1) was performed in spinal dorsal horns and dorsal root ganglions (DRGs) at 10 days after surgery. It was found immunoreactivity for Iba1-positive microglia was higher in the L5 (P=0.004) dorsal horn and in the ipsilateral L4 (P=0.009), L6 (P=0.002), and S1 (P=0.002) dorsal horns in the NP-exposed group than in the sham-operated group. The expression of CGRP was also significantly higher in ipsilateral L3, L4, L6, and S1 segments and in L5 DRGs at 10 days after surgery in the NP-exposed group than in the sham-operated group (P<0.001). Our results indicate that lumbar disc herniation upregulates microglial activity and CGRP expression in many adjacent and ipsilateral lumbar spinal segments. PMID:26713069

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

    PubMed Central

    Weinstein, James N.; Lurie, Jon D.; Tosteson, Tor D.; Tosteson, Anna N. A.; Blood, Emily; Abdu, William A.; Herkowitz, Harry; Hilibrand, Alan; Albert, Todd; Fischgrund, Jeffrey

    2009-01-01

    Study Design Concurrent prospective randomized and observational cohort study. Objectives To assess the 4-year outcomes of surgery vs. non-operative care. Background 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 Non-adherence to treatment assignment caused the intent-to-treat analyses to underestimate the treatment effects. In the 4-year combined as-treated analysis, those receiving surgery demonstrated significantly greater improvement in all the primary outcome measures (mean change Surgery vs. Non-operative; treatment effect; 95% CI): BP (45.6 vs. 30.7; 15.0; 11.8 to 18.1), PF (44.6 vs. 29.7; 14.9; 12.0 to 17.8) and ODI (?38.1 vs. ?24.9; ?13.2; ?15.6 to ?10.9). The percent working was similar between the surgery and non-operative groups, 84.4% vs. 78.4% respectively. Conclusion In a combined as-treated analysis at 4 years, patients who underwent surgery for a lumbar disc herniation achieved greater improvement than non-operatively treated patients in all primary and secondary outcomes except work status. Trial Registration Spine Patient Outcomes Research Trial (SPORT): Intervertebral Disc Herniation; #NCT00000410; http://www.clinicaltrials.gov/ct/show/NCT00000410?order=2 PMID:19018250

  4. Functional and economic outcome following microdiscectomy for lumbar disc herniation in 672 patients.

    PubMed

    Schoeggl, A; Reddy, M; Matula, C

    2003-04-01

    A retrospective assessment of 809 patients operated on in 1990-1998 was performed. A patient-based outcome questionnaire also was incorporated into the study. The outcome was graded according to the Functional Economic Rating scale. A total of 64% of the patients were relieved of their complaints 3.2-10.2 years (median 6.3 years) after lumbar disc surgery. An excellent outcome, defined as Prolo scale of 9 or 10, was achieved in 55.8%, a good outcome (Prolo scale 7 or 8) in 20.7%, a fair outcome (Prolo scale 5 or 6) in 11.4%, and a poor outcome (Prolo scale of

  5. Influences of spinal decompression therapy and general traction therapy on the pain, disability, and straight leg raising of patients with intervertebral disc herniation

    PubMed Central

    Choi, Jioun; Lee, Sangyong; Hwangbo, Gak

    2015-01-01

    [Purpose] The purpose of this study was to identify how spinal decompression therapy and general traction therapy influence the pain, disability, and straight leg raise (SLR) ability of patients with intervertebral disc herniation. [Subjects] The subjects were 30 patients with chronic lumbar pain who were divided into a spinal decompression therapy group (SDTG, n=15), and a general traction therapy group (GTTG, n=15). [Methods] The SDTG used a spinal decompression device, and the GTTG used a lumbar traction device. Both groups received conservative physical therapy three times a week for four weeks. A visual analog scale (VAS) was used to measure the degree of pain the patients with chronic lumbar pain. The Oswestry Disability Index (ODI) was used to measure the degree of functional disability. A goniometer was used to measure the patients’ SLR ability. [Results] Both SDTG and GTTG showed statistically significant decreases in VAS and ODI scores and a statistically significant increase in SLR angle. A comparison of the two groups found no statistically significant differences. [Conclusion] Spinal decompression therapy and general traction therapy are effective at improving the pain, disability, and SLR of patients with intervertebral disc herniation. Thus, selective treatment may be required. PMID:25729196

  6. Microdiscectomy for the Treatment of Lumbar Disc Herniation: An Evaluation of Reoperations and Long-Term Outcomes

    PubMed Central

    Aichmair, Alexander; Du, Jerry Y.; Shue, Jennifer; Evangelisti, Gisberto; Sama, Andrew A.; Hughes, Alexander P.; Lebl, Darren R.; Burket, Jayme C.; Cammisa, Frank P.; Girardi, Federico P.

    2014-01-01

    Design?Retrospective case series. Objective?The objective of this study was to assess the reoperation rate after microdiscectomy for the treatment of lumbar disc herniation (LDH) in patients with???5-year follow-up and identify demographic, perioperative, and outcome-related differences between patients with and without a reoperation. Methods?The medical records, operative reports, and office notes of patients who had undergone microdiscectomy at a single institution between March 1994 and December 2007 were reviewed and long-term follow-up was assessed via a telephone questionnaire. Results?Forty patients (M:24, F:16) with an average age at surgery of 39.9?±?12.5 years (range: 18–80) underwent microdiscectomy at the levels L5–S1 (n?=?28, 70%), L4-L5 (n?=?9, 22.5%), L3–L4 (n?=?2, 5.0%), and L1–L2 (n?=?1, 2.5%). After an average of 40.4?±?40.1 months (range: 1–128), 25% of patients (10/40) required further spine surgery related to the initial microdiscectomy. At an average postoperative follow-up of 11.1?±?4.0 years (range: 5–19), additional symptoms apart from back and leg pain were reported more frequently by patients who underwent a reoperation (p?=?0.005). Patient satisfaction was significantly higher in patients who did not undergo a reoperation (p?=?0.041). For the Oswestry disability index, pain intensity (p?=?0.036), and pain-related sleep disturbances (p?=?0.006) were reported to be more severe in the reoperation group. Conclusions?Microdiscectomy for the treatment of LDH results in a favorable long-term outcome in the majority of cases. The reoperation rate was higher in our series than reported in previous investigations with shorter follow-up. Although there were no statistically significant pre-/perioperative differences between patients with and without reoperation, our findings suggest a difference in self-reported long-term outcome measures. PMID:25278881

  7. Comparison Of Percutaneous Laser Discectomy With Other Modalities For The Treatment Of Herniated Lumbar Discs And Cadaveric Studies Of Percutaneous Laser Discectomy

    NASA Astrophysics Data System (ADS)

    Johansen, W. E.; Smith, Chadwick F.; Vangsness, Thomas; McEleney, Emmett T.; Yamaguchi, Ken; Bales, Peter

    1987-03-01

    Current modalities for treating a herniated lumbar disc include standard open discectomy, microsurgical discectomy, chemonucleoysis and percutaneous discectomy. The Food and Drug Administration has not yet approved percutaneous laser discectomy for clinical investigation. The investigators believe that percutaneous laser discectomy combines the efficacy of both chemonucleoysis and percutaneous discectomy with the safety of both open standard discectomy and microsurgical discectomy. The investigators removed two lumbar discs from a cadaveric spine and weighed each of them. The two lumbar discs weighed in the range of 13.654 grams and 15.713 grams, respectively. The investigators initiated several series of 10 firing cycles from a surgical carbon dioxide laser system. In each firing cycle the surgical carbon dioxide laser system delivered a beam of light energy having an output power of 18.0 watts at pulse duration of 0.045 second at the rate of 15 pulses per second for a period of 6 seconds and vaporized approximately 325 milligrams of disc material. Based on the findings of other investigators reported in the literature relating to percutaneous discectomy the investigators postulated that 10 to 20 firing cycles are required to vaporize 30 to 40% (2.4 to 6.4 grams) of the disc material. The investigators initiated two series of 10 firing cycles in order to perform laser discectomy in a third lumbar disc of the cadaveric spine in situ. The investigators harvested and then bisected the laser-treated third lumbar disc for gross review. Their gross findings indicated a high probability of success For percutaneous laser discectomy.

  8. Risk factors for back pain-related loss of working time after surgery for lumbar disc herniation: a 5-year follow-up study.

    PubMed

    Puolakka, K; Ylinen, J; Neva, M H; Kautiainen, H; Häkkinen, A

    2008-03-01

    The aim of this study is to explore the occurrence and the risk factors of back-related loss of working time in patients undergoing surgery for lumbar disc herniation. One hundred and fifty-two gainfully employed patients underwent surgery for lumbar disc herniation. Two months postoperatively, those patients completed a self-report questionnaire including queries on back and leg pain (VAS), functional capacity (Oswestry disability index--ODI, version 1.0), and motivation to work. After 5 years, lost working time was evaluated by means of a postal questionnaire about sick leave and disability pensions. The cumulative number of back pain-related days-off work was calculated for each patient. All 152 patients, 86 men and 66 women, were prescribed sick leave for the first 2 months. Thereafter, 80 (53%) of them reported back pain-related sick leave or early retirement. A permanent work disability pension due to back problems was awarded to 15 (10%) patients, 5 men (6%) and 10 women (15%). Median number of all work disability days per year was 11 (interquartile range [IQR] 9-37); it was 9 days (IQR 9-22) in patients with minimal disability (ODI score 0-20) at 2 months postoperatively and 67 days (IQR 9-352) in those with moderate or severe disability (ODI > 20; P < 0.001). The respective means were 61, 29, and 140 days/year. Multivariate analysis showed ODI > 20, leg pain, and poor motivation to work to be the risk factors for extension of work disability. Results of the present study show that after the lumbar disc surgery, poor outcome in questionnaire measures the physical functioning (ODI) and leg pain at 2 months postoperatively, as well as poor motivation to work, are associated with the loss of working time. Patients with unfavourable prognosis should be directed to rehabilitation before the loss of employment. PMID:18038161

  9. Risk factors for back pain-related loss of working time after surgery for lumbar disc herniation: a 5-year follow-up study

    PubMed Central

    Ylinen, J.; Neva, M. H.; Kautiainen, H.; Häkkinen, A.

    2007-01-01

    The aim of this study is to explore the occurrence and the risk factors of back-related loss of working time in patients undergoing surgery for lumbar disc herniation. One hundred and fifty-two gainfully employed patients underwent surgery for lumbar disc herniation. Two months postoperatively, those patients completed a self-report questionnaire including queries on back and leg pain (VAS), functional capacity (Oswestry disability index—ODI, version 1.0), and motivation to work. After 5 years, lost working time was evaluated by means of a postal questionnaire about sick leave and disability pensions. The cumulative number of back pain-related days-off work was calculated for each patient. All 152 patients, 86 men and 66 women, were prescribed sick leave for the first 2 months. Thereafter, 80 (53%) of them reported back pain-related sick leave or early retirement. A permanent work disability pension due to back problems was awarded to 15 (10%) patients, 5 men (6%) and 10 women (15%). Median number of all work disability days per year was 11 (interquartile range [IQR] 9–37); it was 9 days (IQR 9–22) in patients with minimal disability (ODI score 0–20) at 2 months postoperatively and 67 days (IQR 9–352) in those with moderate or severe disability (ODI > 20; P < 0.001). The respective means were 61, 29, and 140 days/year. Multivariate analysis showed ODI > 20, leg pain, and poor motivation to work to be the risk factors for extension of work disability. Results of the present study show that after the lumbar disc surgery, poor outcome in questionnaire measures the physical functioning (ODI) and leg pain at 2 months postoperatively, as well as poor motivation to work, are associated with the loss of working time. Patients with unfavourable prognosis should be directed to rehabilitation before the loss of employment. PMID:18038161

  10. Herniated Cervical Disc

    MedlinePLUS

    ... doctor, with the help of a nurse or physical therapist, may also begin education and training on specific exercises to strengthen your neck. These exercises may be performed at home or you may visit a physical therapist for a more specific program to meet ...

  11. Local Irrigation of the Surgical Field with Antibiotics in the End of Procedure Reduces the Infection Rate in Herniated Lumbar Disc Surgery

    PubMed Central

    Kërveshi, Armend; Halili, Nehat; Kastrati, Bujar; Qosja, Faik; Kabashi, Serbeze; Muçaj, Sefedin

    2014-01-01

    Introduction: Reported rate of infections after lumbar discectomy is 1%–15 %. This complication may result in disability or even the death. Aim The aim of the study is to assess the rate of infection associated with lumbar discectomies when combined systemic and local antibiotic prophylaxis was employed. Patients and methods: In this retrospective study we analyzed all patients operated for herniated lumbar disc from 2009 -2012 in our institute. Beside of receiving systemic prophylaxis with 2g of Cefazoline, all patients had their operative field irrigated at the end of operation with Amikacin sulfate injection. Wound was considered infected when local and systemic signs of infection were revealed and were associated with elevated ESR, leukocytosis and elevated CRP. Assessment of infection is done by neurosurgeon during the hospitalization and later at outpatient’s clinic along postoperative course of three months. Results: A total of 604 patients were operated, of those 285 patients (47.2 %) females and 319 males (52.8 %), 12 patients were operated on two levels (1.98 %). Average patient age was 32.5 years (range 20–65 years) Localization of herniated disc was: in L/2-L/3 20 patients or 3.3 %, the L/3-L/4 level 42 patients or 7 % , the L/4 -L /5 262 patients or 43.3 % at the level L/V- S/1 280 patients or 46.3 %. Three patients (0.49%) developed wound infection, two of them superficial infection only with local signs: local pain, redness and leakage. They were treated with oral antibiotics. One with deep wound infection. He presented with local and systemic signs and treated with i.v antibiotics. All the cultures from wound swab revealed staphylococcus aureus. Conclusion: Prophylaxis with systemic antibiotic (Cefazoline 2.0) intravenous administration 30 minutes before the incision and irrigation of operative field with local antibiotic Amikacine sulfate at the end of procedure reduces the infection rate in patients operated for herniated lumbar disc when compared with systemic antibiotic prophylaxis only. PMID:25685087

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

    PubMed Central

    Yang, Hae-sun; Yoo, Won-gyu

    2014-01-01

    [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

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

    PubMed

    Yang, Hae-Sun; Yoo, Won-Gyu

    2014-07-01

    [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

  14. Diffusion-Weighted Imaging for Pretreatment Evaluation and Prediction of Treatment Effect in Patients Undergoing CT-Guided Injection for Lumbar Disc Herniation

    PubMed Central

    Niu, Xiang-Ke; Bhetuwal, Anup

    2015-01-01

    Objective To determine whether a change in apparent diffusion coefficient (ADC) value could predict early response to CT-guided Oxygen-Ozone (O2-O3) injection therapy in patients with unilateral mono-radiculopathy due to lumbar disc herniation. Materials and Methods A total of 52 patients with unilateral mono-radiculopathy received a single intradiscal (3 mL) and periganglionic (5 mL) injection of an O2-O3 mixture. An ADC index of the involved side to the intact side was calculated using the following formula: pre-treatment ADC index = ([ADC involved side - ADC intact side] / ADC intact side) × 100. We analyzed the relationship between the pre-treatment Oswestry Disability Index (ODI) and the ADC index. In addition, the correlation between ODI recovery ratio and ADC index was investigated. The sensitivity and specificity of the ADC index for predicting response in O2-O3 therapy was determined. Results Oswestry Disability Index and the ADC index was not significantly correlated (r = -0.125, p = 0.093). The ADC index and ODI recovery ratio was significantly correlated (r = 0.819, p < 0.001). When using 7.10 as the cut-off value, the ADC index obtained a sensitivity of 86.3% and a specificity of 82.9% for predicting successful response to therapy around the first month of follow-up. Conclusion This preliminary study demonstrates that the patients with decreased ADC index tend to show poor improvement of clinical symptoms. The ADC index may be a useful indicator to predict early response to CT-guided O2-O3 injection therapy in patients with unilateral mono-radiculopathy due to lumbar disc herniation. PMID:26175588

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

    PubMed Central

    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

    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

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

    PubMed Central

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

    2005-01-01

    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. After confirmation of the diagnosis and surgical indication MRI scanning is performed. If a distinct disc herniation is discerned which in addition covers the clinically expected site the patient is eligible for randomization. Depending on the outcome of the randomization scheme the patient will either be submitted to prolonged conservative care or surgery. Surgery will be carried out according to the guidelines and between six and twelve weeks after onset of complaints. The experimental therapy consists of a prolonged conservative treatment under supervision of the general practitioner, which may be followed by surgical intervention in case of persisting or progressive disability. The main primary outcome measure is the disease specific disability of daily functioning. Other primary outcome measures are perceived recovery and intensity of legpain. Secondary outcome measures encompass severity of complaints, quality of life, medical consumption, absenteeism, costs and preference. The main research question will be answered at 12 months after randomization. The total follow-up period covers two years. Discussion Evidence is lacking concerning the optimal treatment of lumbar disc induced sciatica. This pragmatic randomized trial, focusses on the 'timing' of intervention, and will contribute to the decision of the general practictioner and neurologist, regarding referral of patients for surgery. PMID:15707491

  17. A controlled case study of the relationship between environmental risk factors and apoptotic gene polymorphism and lumbar disc herniation.

    PubMed

    Zhang, Yin-Gang; Zhang, Feng; Sun, Zhengmin; Guo, Wentao; Liu, Jian; Liu, Miao; Guo, Xiong

    2013-01-01

    To explore the etiologic role of apoptosis-related genes, environmental risk factors, and their interaction in the occurrence of lumbar disk herniation (LDH), a controlled case study was performed with 128 LDH patients and 132 age- and sex-matched controls. Matrix-assisted laser desorption/ionization, time-of-flight mass spectrometry assay was used to analyze the genotype of nine polymorphism sites in three genes, including Fas -1377G/A rs2234767, Fas -670G/A rs1800682, Fas rs2147420, Fas rs2296603, Fas rs7901656, Fas rs1571019, Fas ligand (FasL) -844C/T rs763110, caspase 9 (CASP9) -1263A>G rs4645978, and CASP9 -712C>T rs4645981. The patients and controls showed similar age and sex, but had significant differences in lumbar load, bed type, amateur sports, and leisure activities (P < 0.05). The correlation analysis revealed that polymorphism of FasL -844C/T (rs763110) and CASP9 -1263A>G (rs4645978) had a significant correlation with LDH, indicating that the genotypes of FasL -844C/T TT and CASP9 -1263A>G GG are probably high-risk genotypes for LDH. The results of environment-gene interaction analysis revealed that, in LDH, the interaction of the FasL -844TT genotype and level III to IV lumbar load was consistent with the ultramultiplying model, and the interaction of the CASP9 rs4645978 GG genotype and level III to IV lumbar load was consistent with the submultiplicative model. Therefore, the risk of LDH was determined by both environmental and genetic risk factors, and the mechanisms of interactions between different genotypes and environmental factors also differed. PMID:23141929

  18. Combination of serum phosphorylated neurofilament heavy subunit and hyperintensity of intramedullary T2W on magnetic resonance imaging provides better prognostic value of canine thoracolumbar intervertebral disc herniation.

    PubMed

    Mashita, Tadahisa; Kamishina, Hiroaki; Nakamoto, Yuya; Akagi, Yosuke; Nakanishi, Ataru; Harasaki, Yusuke; Ozawa, Tsuyoshi; Uemura, Takashi; Kobatake, Yui; Shimamura, Shunsuke; Kitamura, Naoki; Maeda, Sadatoshi; Uzuka, Yuji; Shaw, Gerry; Yasuda, Jun

    2015-04-01

    The aim of this study was to evaluate the prognostic value of concurrent measurement of serum phosphorylated neurofilament heavy subunit (pNF-H) concentration and intramedullary T2W hyperintensity in paraplegic to paraplegic dogs. Our hypothesis was that concurrent measurement of these would provide a more accurate prediction of functional outcome in dogs with thoracolumbar intervertebral disc herniation (IVDH). A prospective case-control clinical study was designed using 94 dogs with acute onset of thoracolumbar IVDH. The association of serum pNF-H concentration, T2W hyperintensity on sagittal MRI (T2H/L2), deep pain perception and surgical outcome were evaluated with logistic regression analysis after three months for all 94 surgically treated dogs. Sensitivity to predict non-ambulatory outcome was compared among pNF-H and T2H/L2 and combination of both. Logistic regression analysis indicated that serum pNF-H concentration and T2H/L2 were significantly correlated with surgical outcome (P<0.05); however, deep pain perception was not (P=0.41). The results of logistic regression analysis indicated that the odds ratios of unsuccessful long-term outcome were 2.6 for serum pNF-H concentration, 1.9 for T2H/L2 and 2.3 for deep pain sensation. The sensitivity and specificity to predict non-ambulatory outcome for using serum parameter pNF-H>2.6 ng/ml, using T2H/L2 value of>0.84 and using both serum pNF-H and T2H/L2, were 95% and 75.7%, 65% and 86.5%, and 90.0% and 97.5%, respectively. Therefore, combined measurements of serum pNF-H and T2H/L2 might be useful for predicting long-term outcome in dogs with thoracolumbar IVDH. PMID:25650056

  19. Comparison of lumbar spine stabilization exercise versus general exercise in young male patients with lumbar disc herniation after 1 year of follow-up

    PubMed Central

    Ye, Chaoqun; Ren, Jixin; Zhang, Jianzheng; Wang, Chongwei; Liu, Zhi; Li, Fang; Sun, Tiansheng

    2015-01-01

    Objective: The safest and most effective conservative treatment for patients with lumbar disc herniation (LDH) has not been established. The purpose of this study was to evaluate the effect of lumbar spine stabilization exercise (LSSE) and general exercise (GE) on pain intensity and functional capacity in young male patients with LDH. Methods: Sixty-three young male adults aged 20 to 29 years with the diagnosis of LDH were enrolled and divided into an LSSE group (n=30) and a GE group (n=33). Patients in both groups received low-power laser (LPL) therapy during the first week of the onset of LDH. Patients in the GE group underwent a GE program. Patients in the LSSE group followed an LSSE program for 3 months. All of the patients were subjected to pain intensity and functional capacity evaluations four times: at pre-and post-LPL therapy, and at 3 months and 1 year post-exercise. Pain intensity of the lower back and legs was evaluated with the visual analogue scale (VAS), and functional capacity was evaluated with the Oswestry Disability Index (ODI). Results: Both groups showed a significant reduction in VAS and ODI scores at 3 and 12 months post-exercise compared with before treatment (P<0.001). The LSSE group showed a significant reduction in the average score of the VAS for low back pain (P=0.012) and the ODI (P=0.003) at 12 months post-exercise compared with the GE group. Conclusions: LSSE and GE are considered as effective interventions for young male patients with LDH. Moreover, LSSE is more effective than GE, and physical therapy, such as LPL, is required during acute LDH. PMID:26309670

  20. The long-term course of patients undergoing alternative and integrative therapy for lumbar disc herniation: 3-year results of a prospective observational study

    PubMed Central

    Shin, Joon-Shik; Lee, Jinho; Kim, Me-riong; Shin, Byung-Cheul; Lee, Myeong Soo; Ha, In-Hyuk

    2014-01-01

    Objectives This study aimed to assess the efficacy and safety of an integrative complementary and alternative medicine (CAM) approach in the management of lumbar herniated disc (LHD) with sciatic pain and investigate pain relapse, use of medical care and surgery rates in patients who actively chose non-surgical CAM treatment for LHD. Study design/Setting This prospective observational study was undertaken at a Korean medicine hospital outpatient setting in Korea. Participants A total of 128 consecutive patients with LHD with a numeric rating scale for leg pain of ?5 completed 6?months of CAM treatment after recruitment from November 2006, and 73/128 participants (57%) attended follow-up 3?years later. Interventions 6?months of CAM treatment (herbal medicine, acupuncture, bee venom pharmacopuncture, and Chuna manipulation). Primary outcome measures Visual analogue scale (VAS) for low back and leg pain, Oswestry Disability Index (ODI), and Short Form (SF)-36 Health Survey. Secondary outcome measures Neurological impairment (muscular weakness, sensory loss, Straight Leg Raise test), MRIs, recurrence of low back pain and/or radiating pain, and use of medical care. Results 92 patients could be assessed for surgical state, of whom 4 replied that they had received surgery. 73 patients attended the 3-year follow-up. The baseline VAS of back pain (4.37±2.70) decreased after treatment (0.90±1.01; p<0.001) and was maintained at 3?years (1.12±1.64; p=0.19). The baseline VAS of leg pain (7.57±1.40) also decreased on treatment (0.82±1.18; p<0.001) and was sustained at 3?years (0.99±1.58; p=0.34). ODI scores declined from 40.74±16.15 to 9.84±9.67 (p<0.001), then decreased further to 6.30±7.19 (p<0.01). SF-36 scores increased from 34.96±13.30 to 69.20±14.96 (p<0.001), reaching 76.19±14.45 (p<0.001) at 3?years. 37 patients reported recurrence of pain and most chose CAM treatment for management of relapse symptoms. Conclusions Although the absence of a control group prevents validation of effectiveness, many patients showed favourable long-term outcomes. Trial registration number ClinicalTrials.gov Identifier: NCT01989403.

  1. Subjective health complaints in patients with lumbar radicular pain and disc herniation are associated with a sex - OPRM1 A118G polymorphism interaction: a prospective 1-year observational study

    PubMed Central

    2014-01-01

    Background Earlier observations show that development of persistent pain may be associated with the genetic variability in the gene encoding for the ?-opioid receptor 1, the OPRM1 A118G (rs1799971). The aim of this study was to investigate the association between OPRM1 genotype and subjective health complaints in patients with radicular pain and disc herniation. Methods A prospective, 1-year observational study was conducted at a hospital back clinic, including 118 Caucasian patients with lumbar radicular pain and MRI confirmed disc herniation. Single nucleotide polymorphism genotyping regarding the OPRM1 A118G was performed. The data of individuals with AA versus AG or GG were analysed separately by linear mixed models. The Subjective Health Complaints Inventory (0-81) including 27 common complaints experienced the previous month on a scale from not at all (0) to severe (3) was used as outcome. Pain, prior duration of leg pain, age, smoking status, and lumbar disc surgery were considered as covariates. Results In total 23 of 118 patients were carriers of the OPRM1 G-allele. All patients except female carriers of the G-allele reported a decrease in pain from baseline to 1 year. Female carriers of the G-allele reported significantly higher subjective health complaints score during the study time span than male carriers of the G-allele when controlling for pain and pain duration. Conclusion The present data indicate that, when controlling for pain intensity and duration, subjective health complaints are associated with a sex - OPRM1 A118G polymorphism interaction in patients with radicular pain. PMID:24884878

  2. Changes in the total Oswestry Index and its ten items in females and males pre- and post-surgery for lumbar disc herniation: a 1-year follow-up

    PubMed Central

    Kautiainen, Hannu; Järvenpää, Salme; Arkela-Kautiainen, Marja; Ylinen, Jari

    2006-01-01

    To study the characteristics and changes in the total Oswestry Disability Index (ODI) and in its ten component items in female and male patients pre- and post-surgery for lumbar disc herniation. Ninety-eight patients [mean (SD) age 43 (13), 61% males] undergoing lumbar disc herniation surgery were selected for this clinical 12-month follow-up. Subjective disability and back and leg pain were assessed by ODI version 1.0 and the visual analog scale. Pre-operatively females had a significantly higher mean (SD) total ODI [59(3)] than males [51(2)] (P = 0.030). Females were more disabled in the walking, sex life, social life and travelling items of the ODI compared to males. The total Oswestry decreased by 38 (95% CI ? 44 to ? 31) in females and by 34 (? 39 to ? 30) in males at the 1-year follow-up. Most of the improvement (88% in females and 80% in males) occurred during the first 6 weeks; thereafter the changes were minor. In males the changes were greatest in pain, social life and travelling and in females in walking, social life and travelling. Internal consistency value of ODI was 0.88 (95% CI 0.82–0.91). Item analysis of the ODI showed that all the items except pain had high corrected item correlation. As recovery following lumbar disc surgery occurred to a great extent during the first 6 weeks, the early post-operative outcome appears to be quite a reliable indicator of the overall post-operative outcome over the 1-year follow-up. The ODI proved to capture a wide range of disability in these lumbar disc surgery patients, thereby supporting the future use of the index. The “pain intensity” component, which collects data on the use of painkillers in version 1.0 of the ODI did not support the item structure of the index in this study. The use of ODI version 2.0 might remove this problem. PMID:16912888

  3. Changes in the total Oswestry Index and its ten items in females and males pre- and post-surgery for lumbar disc herniation: a 1-year follow-up.

    PubMed

    Häkkinen, Arja; Kautiainen, Hannu; Järvenpää, Salme; Arkela-Kautiainen, Marja; Ylinen, Jari

    2007-03-01

    To study the characteristics and changes in the total Oswestry Disability Index (ODI) and in its ten component items in female and male patients pre- and post-surgery for lumbar disc herniation. Ninety-eight patients [mean (SD) age 43 (13), 61% males] undergoing lumbar disc herniation surgery were selected for this clinical 12-month follow-up. Subjective disability and back and leg pain were assessed by ODI version 1.0 and the visual analog scale. Pre-operatively females had a significantly higher mean (SD) total ODI [59(3)] than males [51(2)] (P = 0.030). Females were more disabled in the walking, sex life, social life and travelling items of the ODI compared to males. The total Oswestry decreased by 38 (95% CI - 44 to - 31) in females and by 34 (- 39 to - 30) in males at the 1-year follow-up. Most of the improvement (88% in females and 80% in males) occurred during the first 6 weeks; thereafter the changes were minor. In males the changes were greatest in pain, social life and travelling and in females in walking, social life and travelling. Internal consistency value of ODI was 0.88 (95% CI 0.82-0.91). Item analysis of the ODI showed that all the items except pain had high corrected item correlation. As recovery following lumbar disc surgery occurred to a great extent during the first 6 weeks, the early post-operative outcome appears to be quite a reliable indicator of the overall post-operative outcome over the 1-year follow-up. The ODI proved to capture a wide range of disability in these lumbar disc surgery patients, thereby supporting the future use of the index. The "pain intensity" component, which collects data on the use of painkillers in version 1.0 of the ODI did not support the item structure of the index in this study. The use of ODI version 2.0 might remove this problem. PMID:16912888

  4. Idiopathic spinal cord herniation.

    PubMed

    Miura, Y; Mimatsu, K; Matsuyama, Y; Yoneda, M; Iwata, H

    1996-02-01

    Idiopathic spinal cord herniation is a rare disease, few cases having been reported. We encountered a case of idiopathic spinal cord herniation presenting with severe spasticity in the right leg and urinary dysfunction. The spinal cord was herniated into a cavity created by duplication of the dura mater and resection of the inner layer improved the neurological deficits. MRI, myelography, and CT myelography were useful for diagnosing this disease. Four radiological signs of spinal cord herniation are described. PMID:8692428

  5. Lipoxin A4 attenuates radicular pain possibly by inhibiting spinal ERK, JNK and NF-?B/p65 and cytokine signals, but not p38, in a rat model of non-compressive lumbar disc herniation.

    PubMed

    Miao, G-S; Liu, Z-H; Wei, S-X; Luo, J-G; Fu, Z-J; Sun, T

    2015-08-01

    Inflammatory response induced by protrused nucleus pulposus (NP) has been shown to play a crucial role in the process of radicular pain. Lipoxins represent a unique class of lipid mediators that have anti-inflammatory and pro-resolving action. The present study was undertaken to investigate if intrathecal lipoxin A4 (LXA4) could alleviate mechanical allodynia in the rat models of application of NP to the L5 dorsal root ganglion (DRG). Non-compressive models of application of NP to L5 DRG were established and intrathecal catheterization for drug administration was performed in rats. Daily intrathecal injection of vehicle or LXA4 (10ng or 100ng) was performed for three successive days post-operation. Mechanical thresholds were tested and the ipsilateral lumbar (L4-L6) segment of spinal dorsal horns were removed for the determination of tumor necrosis factor-? (TNF-?), IL-1?, transforming growth factor-?1 (TGF-?1) and IL-10 expression and NF-?B/p65, extracellular signal-regulated kinase (ERK), C-Jun N-terminal kinase (JNK) and P38 expression. Application of NP to DRG in rats induced mechanical allodynia, increased the expression of pro-inflammatory factors (TNF-? and IL-1?), NF-?B/p65, the phosphorylated-ERK (p-ERK), -JNK (p-JNK) and -P38 (p-p38) and decreased the expression of anti-inflammatory cytokines (TGF-?1 and IL-10) in the ipsilateral lumbar (L4-L6) segment of spinal dorsal horns. Intrathecal injection of LXA4 alleviated the development of neuropathic pain, inhibited the upregulation of pro-inflammatory cytokines (TNF-? and IL-1?), upregulated the expression of anti-inflammatory cytokines (TGF-?1 and IL-10) and attenuated the activation of NF-?B/p65, p-ERK, p-JNK, but not p-p38, in a dose-dependent manner. In this study, we have demonstrated that LXA4 potently alleviate radicular pain in a rat model of non-compressive lumbar disc herniation. The anti-inflammatory and pro-resolution properties of LXA4 have shown a great promise for the management of radicular pain caused by intervertebral disc herniation. PMID:25943485

  6. Electroburning of few-layer graphene flakes, epitaxial graphene, and turbostratic graphene discs in air and under vacuum

    PubMed Central

    Richter, Nils; Convertino, Domenica; Coletti, Camilla; Balestro, Franck; Wernsdorfer, Wolfgang; Kläui, Mathias; Affronte, Marco

    2015-01-01

    Summary Graphene-based electrodes are very promising for molecular electronics and spintronics. Here we report a systematic characterization of the electroburning (EB) process, leading to the formation of nanometer-spaced gaps, on different types of few-layer graphene (namely mechanically exfoliated graphene on SiO2, graphene epitaxially grown on the C-face of SiC and turbostratic graphene discs deposited on SiO2) under air and vacuum conditions. The EB process is found to depend on both the graphene type and on the ambient conditions. For the mechanically exfoliated graphene, performing EB under vacuum leads to a higher yield of nanometer-gap formation than working in air. Conversely, for graphene on SiC the EB process is not successful under vacuum. Finally, the EB is possible with turbostratic graphene discs only after the creation of a constriction in the sample using lithographic patterning. PMID:25821711

  7. 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

    Filippiadis, Dimitrios K. Mazioti, A. Papakonstantinou, O. Brountzos, E.; Gouliamos, A.; Kelekis, N. Kelekis, A.

    2012-10-15

    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.

  8. [Effects of 3-hydroxypyridine and succinic acid derivatives on the dynamics of dorsalgia and affective disorders after surgical treatment of disc herniation].

    PubMed

    Volchegorski?, I A; Mester, K M

    2010-01-01

    A prospective, placebo-controlled randomized study of the effects of 3-hydropxypyridine and succinic acid derivatives (emoxipine, reamberin and mexi the early dynamics of dorsalgia and the corresponding affective disorders has been performed in 136 patients after surgical treatment of lumbal disc hen It is established that a two-week administration of all preparations reduced the manifestations of depression during 3.5 months after spinal surgery. The course of emoxipine (150 mg, i.v., daily) produced an antidepressant effect without any changes in the dynamics of dorsalgia, psychological dysada (PD), and quality of life (QL). The 14-day administration of reamberin (400 ml, i.v., daily) significantly reduced in the manifestations of depression and pathic pain, without any effect upon nociceptive pain, PD, and QL dynamics. The two-week course of mexidol (300 mg, i.v., daily) led to the most pron antidepressant effect, which was accompanied by the attenuation of both nociceptive and neuropathic pain, a decrease in PD, and appreciable increase in ter the surgical treatment. PMID:20184287

  9. Cervical arthroplasty using ProDisc-C Case Report

    PubMed Central

    Nica, DA; Copaciu, R

    2013-01-01

    Cervical disc replacement is an emerging motion-preserving technology in the surgical treatment of the cervical degenerative disc disorders used as an alternative to the classic interbody fusion. We present a case report of a patient diagnosed with C6-7 right disc herniation who underwent anterior discectomy and received a total disc replacement using ProDisc C artificial disc prosthesis. PMID:23599830

  10. Spontaneous Regression of a Large Lumbar Disc Extrusion

    PubMed Central

    Ryu, Sung-Joo

    2010-01-01

    Although the spontaneous disappearance or decrease in size of a herniated disc is well known, that of a large extruded disc has rarely been reported. This paper reports a case of a spontaneous regression of a large lumbar disc extrusion. The disc regressed spontaneously with clinical improvement and was documented on a follow up MRI study 6 months later. The literature is reviewed and the possible mechanisms of spontaneous disc regression are discussed. PMID:21082061

  11. SPORT Lumbar Intervertebral Disk Herniation and Back Pain

    PubMed Central

    Pearson, Adam M.; Blood, Emily A.; Frymoyer, John W.; Herkowitz, Harry; Abdu, William A.; Woodward, Randy; Longley, Michael; Emery, Sanford E.; Lurie, Jon D.; Tosteson, Tor D.; Weinstein, James N.

    2009-01-01

    Study Design Diskectomy candidates with at least 6 weeks of sciatica and confirmatory imaging were enrolled in a randomized or observational cohort. Objective This study sought to determine: (1) whether diskectomy resulted in greater improvement in back pain than nonoperative treatment, and (2) whether herniation location and morphology affected back pain outcomes. Summary of Background Data Previous studies have reported that lumbar diskectomy is less successful for relief of back pain than leg pain and patients with central disc herniations or protrusions have worse outcomes. Methods Patients underwent diskectomy or received “usual” nonoperative care. Data from the randomized cohort and observational cohort were combined in an as-treated analysis. Low back pain was recorded on a 0 to 6 point scale, and changes in low back pain were compared between the surgical and nonoperative treatment groups. The effects of herniation location and morphology on back pain outcomes were determined. Results The combined analysis included 1191 patients with 775 undergoing surgery within 2 years, whereas 416 remained nonoperative. Overall, leg pain improved more than back pain in both treatment groups. Back pain improved in both surgical and nonoperative patients, but surgical patients improved significantly more (treatment effect favoring surgery -0.9 at 3 months, -0.5 at 2 years, P < 0.001). Patients who underwent surgery were more likely to report no back pain than nonoperative patients at each follow-up period (28.0% vs. 12.0% at 3 months, P < 0.001, 25.5% vs. 17.6% at 2 years, P = 0.009). At baseline, central herniations were associated with more severe back pain than more lateral herniations (4.3 vs. 3.9, P = 0.012). Patients with central herniations and protrusions had a beneficial treatment effect from surgery similar to the overall surgical group. Conclusion Diskectomy resulted in greater improvement in back pain than nonoperative treatment, and this difference was maintained at 2 years for all herniation locations and morphologies. PMID:18277876

  12. A collagen-GAG matrix for the growth of intervertebral disc tissue

    E-print Network

    Hastreiter, Dawn (Dawn Marie), 1973-

    2002-01-01

    Intervertebral disc (IVD) degeneration and herniation is a significant problem, more so in the aviation field. The IVD also changes during spaceflight. Current treatments for IVD problems can have unfavorable long-term ...

  13. A new pathological classification of lumbar disc protrusion and its clinical significance.

    PubMed

    Ma, Xin-long

    2015-02-01

    Lumbar disc protrusion is common. Its clinical manifestations and treatments are closely related to the pathological changes; however, the pathological classification of lumbar disc protrusion is controversial. This article introduces a new pathological classification comprising four types of lumbar disc protrusion according to intraoperative findings. The damage-herniation type is probably caused by injury and is characterized by soft herniation, the capsule can easily be cut and the broken disc tissue blocks overflow or is easily removed. The broken disc substances should be completely removed; satisfactory results can be achieved by minimally invasive endoscopic surgery. The degeneration-protrusion type is characterized by hard and tough protrusions and the pathological process by degeneration and proliferative reaction. The nerve should be decompressed and relaxed with minimally invasive removal of the posterior wall; the bulged or protruded disc often need not be excised. The posterior vertebral osteochondrosis with disc protrusion type is characterized by deformity of the posterior vertebral body, osteochondral nodules and intervertebral disc protrusion. The herniated and fragmented disc tissue should be removed with partially protruding osteochondral nodules. Intervertebral disc cyst is of uncertain pathogenesis and is characterized by a cyst that communicates with the disc. Resection of the cyst under microscopic or endoscopic control can achieve good results; and whether the affected disc needs to be simultaneously resected is controversial. The new pathological classification proposed here is will aid better understanding of pathological changes and pathogenesis of lumbar disc protrusion and provides a reference for diagnosis and treatment. PMID:25708029

  14. Lumbar Disc Screening Using Back Pain Questionnaires: Oswestry Low Back Pain Score, Aberdeen Low Back Pain Scale, and Acute Low Back Pain Screening Questionnaire

    PubMed Central

    Kim, Do Yeon; Oh, Chang Hyun; Park, Hyung Chun; Park, Chong Oon

    2012-01-01

    Objective To evaluate the usefulness of back pain questionnaires for lumbar disc screening among Korean young males. Methods We carried out a survey for lumbar disc screening through back pain questionnaires among the volunteers with or without back pain. Three types of back pain questionnaire (Oswestry Low Back Pain Score, Aberdeen Low Back Pain Scale, and Acute Low Back Pain Screeing Questionnaire) were randomly assigned to the examinees. The authors reviewed lumbar imaging studies (simple lumbar radiographs, lumbar computed tomography, and magnetic resolutional images), and the severity of lumbar disc herniation was categorized according to the guidelines issued by the Korean military directorate. We calculated the relationship between the back pain questionnaire scores and the severity of lumbar disc herniation. Results The scores of back pain questionnaires increased according to the severity of lumbar disc herniation. But, the range of scores was very vague, so it is less predictable to detect lumbar disc herniation using only back pain questionnaires. The sensitivity between the back pain questionnaires and the presence of lumbar disc herniation was low (16-64%). Conclusion Screening of lumbar disc herniation using only back pain questionnaires has limited value. PMID:25983807

  15. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture disc is the only pressure relief device on the tank,...

  16. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture disc is the only pressure relief device on the tank,...

  17. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture disc is the only pressure relief device on the tank,...

  18. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture disc is the only pressure relief device on the tank,...

  19. 46 CFR 64.61 - Rupture disc.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.61 Rupture disc. If a rupture disc is the only pressure relief device on the tank,...

  20. Assessing the Risk of Disc Heniation Related to Landing Impact Following Long-duration Spacecraft

    NASA Technical Reports Server (NTRS)

    Somers, J. T.; Newby, N..; Wells, J.

    2014-01-01

    Previous research has shown that crewmembers returning on the Space Shuttle have an increased incidence of herniated nucleus pulposus after spaceflight. This increased risk is thought to be related to disc volume expansion due to unloading and prolonged exposure to microgravity. Although there is an increased risk of disc herniation in Space Shuttle astronauts, it is unknown if dynamic landing loads further contribute to the risk of herniation. To determine if dynamic loads increase the risk of incidence, data from crewmembers (excluding cosmonauts) returning on the Soyuz spacecraft will be compared to Space Shuttle astronauts. These data will be obtained from the Lifetime Surveillance of Astronaut Health (LSAH) Project at NASA. Severity and incidence after spaceflight will be mined from the data, and statistical analyses will be used to determine if Soyuz crewmembers have a higher incidence of disc herniation than Space Shuttle crewmembers. The results are expected to show no difference between Space Shuttle and Soyuz crewmembers, indicating that higher dynamic loads on landing and long-duration spaceflight do not significantly increase the risk of disc herniation. If no difference is shown between the two crewmember populations, then disc volume expansion due to microgravity does not significantly increase the risk of injury due to dynamic loads for deconditioned crewmembers. Any risk associated with deconditioning would be primarily due to bone structure changes and resulting bone strength changes. This study is an important first step in determining whether the spinal disc plays a role in injury due to dynamic loads.

  1. Repeated microendoscopic discectomy for recurrent lumbar disk herniation

    PubMed Central

    Hou, Tianyong; Zhou, Qiang; Dai, Fei; Luo, Fei; He, Qingyi; Zhang, Jinsong; Xu, Jianzhong

    2015-01-01

    OBJECTIVES: To explore the microendoscopic discectomy technique and inclusion criteria for the treatment of recurrent lumbar disc herniation and to supply feasible criteria and technical notes to avoid complications and to increase the therapeutic effect. METHODS: A consecutive series of 25 patients who underwent posterior microendoscopic discectomy for recurrent lumbar disc herniation were included. The inclusion criteria were as follows: no severe pain in the lumbar region, no lumbar instability observed by flexion-extension radiography and no intervertebral discitis or endplate damage observed by magnetic resonance imaging. All patients were diagnosed by clinical manifestations and imaging examinations. RESULTS: Follow-up visits were carried out in all cases. Complications, such as nerve injuries, were not observed. The follow-up outcomes were graded using the MacNab criteria. A grade of excellent was given to 12 patients, good to 12 patients and fair to 1 patient. A grade of excellent or good occurred in 96% of cases. One patient relapsed 3 months after surgery and then underwent lumbar interbody fusion and inner fixation. The numerical rating scale of preoperative leg pain was 7.4± 1.5, whereas it decreased to 2.1±0.8 at 7 days after surgery. The preoperative Oswestry disability index of lumbar function was 57.5±10.0, whereas it was 26.0±8.5 at 7 days after surgery. CONCLUSION: In these cases, microendoscopic discectomy was able to achieve satisfactory clinical results. Furthermore, it has advantages over other methods because of its smaller incision, reduced bleeding and more efficient recovery. PMID:25789521

  2. Trans-mediastinal herniation of bulla: Semilunar sign

    PubMed Central

    Singh, Sheetu; Singh, Nishtha; Singh, Virendra

    2015-01-01

    Trans-mediastinal herniation of lung is seen occasionally but herniation of bulla across the mediastinum is rare. We report two cases with trans-mediastinal herniation of bullae leading to an unusual line appearing near the mediastinum. We propose the name ‘Semilunar sign’for this radiological sign because of its resemblance to the half-moon shape.

  3. Percutaneous diode laser disc nucleoplasty

    NASA Astrophysics Data System (ADS)

    Menchetti, P. P.; Longo, Leonardo

    2004-09-01

    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%.

  4. Spinal cord herniation with characteristic bone change: a case report

    PubMed Central

    Imai, Tasuku; Nakane, Yukimi; Tachibana, Eiji; Ogura, Koichiro

    2015-01-01

    ABSTRACT Spinal cord herniation (SCH) is a rare disease characterized by herniation of the thoracic spinal cord through an anterior dural defect, presenting with progressive myelopathy. A case of a 69-year-old woman who presented with Brown-Sequard syndrome and a bone defect, in which an osteophyte created a hemisphere-like cavity with spinal cord herniation, is presented. The strangled spinal cord was released, and the defect was closed microsurgically using an artificial dural patch to prevent re-herniation. Postoperatively, the patient experienced gradual improvement in neurologic function. The SCH mechanism and surgical strategy are discussed. PMID:26412899

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

    PubMed

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

    2014-09-22

    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

  6. Emergency Neurological Life Support: Intracranial Hypertension and Herniation.

    PubMed

    Stevens, Robert D; Shoykhet, Michael; Cadena, Rhonda

    2015-12-01

    Sustained intracranial hypertension and acute brain herniation are "brain codes," signifying catastrophic neurological events that require immediate recognition and treatment to prevent irreversible injury and death. As in cardiac arrest, a brain code mandates the organized implementation of a stepwise management algorithm. The goal of this emergency neurological life support protocol is to implement an evidence-based, standardized approach to the evaluation and management of patients with intracranial hypertension and/or herniation. PMID:26438459

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

    SciTech Connect

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

    2010-10-15

    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.

  8. 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

  9. Herniation of transverse colon into mediastinum after pedicled omental grafting for mediastinitis: report of a case.

    PubMed

    Hashimoto, Makoto; Yamauchi, Akihiko; Shimabuku, Masamori; Higami, Tetsuya

    2015-11-01

    We describe a rare complication and the treating experience of it after pedicled omental grafting for mediastinitis. The patient was diagnosed as an acute mediastinitis soon after the total arch replacement was performed. A two-staged strategy to treat postoperative mediastinitis was scheduled, i.e., the setting up of a vacuum-assisted closure system until the improvement of inflammation followed by wound closure with pedicled omental grafting. The treatment for acute mediastinitis was successful and the patient followed a favorable postoperative course. During the follow-up, chest X-ray film suggested the gradual enlargement of mediastinum and CT showed the herniation of transverse colon into mediastinum. Surgical correction for the hernia was scheduled and performed successfully by the laparoscopic procedure to prevent a possible cardiac and pulmonary dysfunction. PMID:24091537

  10. Internal herniation through a defect in the transverse mesocolon.

    PubMed

    Alaker, Medhat; Mathias, Jegadish

    2014-01-01

    Internal hernias are rare, constituting 5.8% of all intestinal obstruction cases. Congenital transverse mesocolon hernias in adults are specifically rare. We hereby present a case of an adult female presenting with acute intestinal obstruction. Her CT scan showed classic signs of internal herniations: 'Whirlpool sign', crowding of bowel loops in the upper compartment and the absence of caecum from the Right Iliac Fossa. At operation, she was found to have a congenital defect in the transverse mesocolon, through which have herniated the terminal ileum, caecum and the proximal half of the ascending colon. They have furthermore rotated 360° about the axis of the pedicle forming a volvulus. The bowel was viable. The herniated bowel was derotated, and reduced through the defect, the defect was closed with polydioxanone sutures, and the caecum and ascending colon was fixed to the lateral abdominal wall. PMID:24567183

  11. Optical disc discrimination method

    NASA Astrophysics Data System (ADS)

    Nakahara, Hironori; Takeshita, Nobuo

    2015-09-01

    We propose a method for identifying the type of a disc inserted into an optical drive. The disc is irradiated with light from an LED light source and the diffracted light from the information recording layer of the disc is detected by using the movement of the disc during disc loading. Results of the optical simulation agree well with the experimental results. A total of 61 discs were measured, and it was confirmed that these discs can be distinguished accurately.

  12. Artificial Disc Replacement

    MedlinePLUS

    ... treat this condition, alternatives to disc replacement include fusion, nonoperative care or no treatment. Typically, surgery is ... operative treatment for disc pain has been spinal fusion. This is a surgical procedure in which disc ...

  13. D-Zero Cryostat Supplemental Rupture Disc

    SciTech Connect

    Mulholland, G.T.; /Fermilab

    1987-08-03

    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.

  14. Intermittent swelling in the chest; a case of spontaneous intermittent lung herniation

    PubMed Central

    Bangalore Lakshminarayana, Umesh; Cowen, Michael; Kastelik, Jack A; Morjaria, Jaymin B

    2013-01-01

    Herniation of the lung is uncommon and occurs due to protrusion of the lung beyond the confines of the thoracic cavity through an abnormal opening in the chest wall. Any condition associated with raised intrathoracic pressure or that which weakens the thoracic wall may result in lung herniation. We present a case of spontaneous lung herniation which was managed successfully by minimally invasive thoracic surgery. PMID:24177461

  15. Non-reclosing pressure relief device for vacuum systems

    DOEpatents

    Swansiger, W.A.

    1994-02-08

    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.

  16. Non-reclosing pressure relief device for vacuum systems

    DOEpatents

    Swansiger, William A. (Livermore, CA)

    1994-01-01

    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.

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

    PubMed

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

    2015-01-01

    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

  18. Pancreatic herniation: a rare cause of acute pancreatitis?

    PubMed Central

    Kumar, Prashant; Turp, Matthew; Fellows, Sarah; Ellis, Jonathan

    2013-01-01

    Acute pancreatitis is a common and potentially fatal condition, with several well-known causes including gallstones, excessive alcohol consumption and specific medications. We report a case of an 89-year-old man presenting with acute pancreatitis, which we believe to be secondary to a diaphragmatic herniation of the pancreas. This extremely rare anatomical abnormality can be found incidentally in the asymptomatic patient or may present with a variety of acute symptoms. However, there have been only isolated reports of these cases presenting as acute pancreatitis. While the majority of acute pancreatitis cases can be explained by common causes, it is important that clinicians be aware of and should consider investigating for other more unusual possibilities, such as pancreatic herniation, before labelling an episode as ‘idiopathic’. PMID:24343805

  19. Jejunojejunal intussusception with internal herniation in the stomach.

    PubMed

    Khanna, Seema; Kumar, Dinesh; Khanna, Rahul; Gupta, Sanjeev Kumar

    2014-04-01

    Jejunojejunal intussusception with internal herniation of the stomach through a gastrojejunostomy stoma is one of the rarest complications of the previous gastric surgery. The incidence is reported to be less than 0.1 %. An elderly male presented to the emergency room with signs of intestinal obstruction for 1 day. There was also history of appearance of a lump in the mid-abdomen. A primarily healed midline scar of the previous surgery was present; the details of which were not known. X ray abdomen in the erect posture showed multiple air fluid levels. Ultrasonography (USG) revealed dilated stomach with central hyperechogenicity with a peripheral rim of decreased echogenecity. Contrast-enhanced computed tomography (CECT) scan showed jejunojejunal intussusception with internal herniation of the stomach. On laparotomy, it was found that there was a previous gastrojejunostomy with jejunal invagination leading to gangrene of a segment. Resection anastomosis was done. The postoperative period was uneventful. PMID:24891784

  20. Idiopathic Spinal Cord Herniation Presented as Brown-Sequard Syndrome : A Case Report and Surgical Outcome

    PubMed Central

    Ju, Min-Wook; Youm, Jin-Young; Kwon, Hyon-Jo

    2015-01-01

    Spinal cord herniation is a rare condition that has become increasingly recognised in the last few years. The authors report a case of idiopathic spinal cord herniation in a 33 year old woman performed with progressive Brown-Sequard syndrome. The diagnosis was made on MR imaging. After repairing the herniation, the patient made a gradual improvement. Potential causes are discussed, including a possible role of dural defect. In conclusion, idiopathic spinal cord herniation is a potentially treatable condition that should be more readily diagnosed that increasing awareness and improved imaging techniques. PMID:26539277

  1. Cervical lung lobe herniation in dogs identified by fluoroscopy

    PubMed Central

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

    2013-01-01

    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

  2. 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

  3. Automotive disc brake squeal

    NASA Astrophysics Data System (ADS)

    Kinkaid, N. M.; O'Reilly, O. M.; Papadopoulos, P.

    2003-10-01

    Disc brake squeal remains an elusive problem in the automotive industry. Since the early 20th century, many investigators have examined the problem with experimental, analytical, and computational techniques, but there is as yet no method to completely suppress disc brake squeal. This paper provides a comprehensive review and bibliography of works on disc brake squeal. In an effort to make this review accessible to a large audience, background sections on vibrations, contact and disc brake systems are also included.

  4. Turbine disc sealing assembly

    DOEpatents

    Diakunchak, Ihor S.

    2013-03-05

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    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%.

  6. A rare case of femoral herniation of female internal genitalia

    PubMed Central

    Ambedkar, Vivek; Singh, Abhilash; Bain, Jayanta; Singh, Lal Mani

    2015-01-01

    We report a rare case with herniation of the uterus, fallopian tube, and ovary in a femoral hernia. A female patient was admitted with complain of the painful lump in the left groin. Clinical examination indicated strangulated femoral hernia, which necessitated an emergency surgery. During surgical procedure, the uterine tube, left fallopian tube and left ovary, were observed as the contents of the hernia. The contents were reduced back into the pelvic cavity, and the hernia was repaired. The patient made good recovery postsurgery. PMID:26283851

  7. Symptomatic Thoracic Spinal Cord Herniation: Case Series and Technical Report

    PubMed Central

    Hawasli, Ammar H.; Ray, Wilson Z.; Wright, Neill M.

    2014-01-01

    Background and Importance Idiopathic spinal cord herniation (ISCH) is an uncommon condition located predominantly in the thoracic spine and often associated with a remote history of a major traumatic injury. ISCH has an incompletely described presentation and unknown etiology. There is no consensus on treatment algorithm and surgical technique, and there is little data on clinical outcomes. Clinical Presentation In this case series and technical report, we describe the atypical myelopathy presentation, remote history of traumatic injury, radiographic progression, treatment, and outcomes of 5 patients treated at Washington University for symptomatic ISCH. A video showing surgical repair is presented. In contrast to classic compressive myelopathy symptomology, ISCH patients presented with an atypical myelopathy, characterized by asymmetric motor and sensory deficits and early-onset urinary incontinence. Clinical deterioration correlated with progressive spinal cord displacement and herniation observed on yearly spinal imaging in a patient imaged serially due to multiple sclerosis. Finally compared to compressive myelopathy in the thoracic spine, surgical treatment of ISH led to rapid improvement despite long duration of symptoms. Conclusion Symptomatic ISCH presents with atypical myelopathy and slow temporal progression and can be successfully managed with surgical repair. PMID:24871148

  8. Radially truncated galactic discs

    E-print Network

    Richard de Grijs; Michiel Kregel; Karen H. Wesson

    2001-02-02

    We present the first results of a systematic analysis of radially truncated exponential discs for four galaxies of a complete sample of disc-dominated edge-on spiral galaxies. The discs of our sample galaxies are truncated at similar radii on either side of their centres. With possible the exception of the disc of ESO 416-G25, it appears that the truncations in our sample galaxies are closely symmetric, in terms of both their sharpness and the truncation length. However, the truncations occur over a larger region and not as abruptly as found in previous studies. We show that the truncated luminosity distributions of our sample galaxies, if also present in the mass distributions, comfortably meet the requirements for longevity. The formation and maintenance of disc truncations are likely closely related to stability requirements for galactic discs.

  9. Vacuum force

    NASA Astrophysics Data System (ADS)

    Han, Yongquan

    2015-03-01

    To study on vacuum force, we must clear what is vacuum, vacuum is a space do not have any air and also ray. There is not exist an absolute the vacuum of space. The vacuum of space is relative, so that the vacuum force is relative. There is a certain that vacuum vacuum space exists. In fact, the vacuum space is relative, if the two spaces compared to the existence of relative vacuum, there must exist a vacuum force, and the direction of the vacuum force point to the vacuum region. Any object rotates and radiates. Rotate bend radiate- centripetal, gravity produced, relative gravity; non gravity is the vacuum force. Gravity is centripetal, is a trend that the objects who attracted wants to Centripetal, or have been do Centripetal movement. Any object moves, so gravity makes the object curve movement, that is to say, the radiation range curve movement must be in the gravitational objects, gravity must be existed in non vacuum region, and make the object who is in the region of do curve movement (for example: The earth moves around the sun), or final attracted in the form gravitational objects, and keep relatively static with attract object. (for example: objects on the earth moves but can't reach the first cosmic speed).

  10. Surgical vs Nonoperative Treatment for Lumbar Disk Herniation

    PubMed Central

    Weinstein, James N.; Lurie, Jon D.; Tosteson, Tor D.; Skinner, Jonathan S.; Hanscom, Brett; Tosteson, Anna N. A.; Herkowitz, Harry; Fischgrund, Jeffrey; Cammisa, Frank P.; Albert, Todd; Deyo, Richard A.

    2008-01-01

    Context For patients with lumbar disk herniation, the Spine Patient Outcomes Research Trial (SPORT) randomized trial intent-to-treat analysis showed small but not statistically significant differences in favor of diskectomy compared with usual care. However, the large numbers of patients who crossed over between assigned groups precluded any conclusions about the comparative effectiveness of operative therapy vs usual care. Objective To compare the treatment effects of diskectomy and usual care. Design, Setting, and Patients Prospective observational cohort of surgical candidates with imaging-confirmed lumbar intervertebral disk herniation who were treated at 13 spine clinics in 11 US states and who met the SPORT eligibility criteria but declined randomization between March 2000 and March 2003. Interventions Standard open diskectomy vs usual nonoperative care. Main Outcome Measures Changes from baseline in the Medical Outcomes Study Short-Form Health Survey (SF-36) bodily pain and physical function scales and the modified Oswestry Disability Index (American Academy of Orthopaedic Surgeons/MODEMS version). Results Of the 743 patients enrolled in the observational cohort, 528 patients received surgery and 191 received usual nonoperative care. At 3 months, patients who chose surgery had greater improvement in the primary outcome measures of bodily pain (mean change: surgery, 40.9 vs nonoperative care, 26.0; treatment effect, 14.8; 95% confidence interval, 10.8-18.9), physical function (mean change: surgery, 40.7 vs nonoperative care, 25.3; treatment effect, 15.4; 95% CI, 11.6-19.2), and Oswestry Disability Index (mean change: surgery, ?36.1 vs nonoperative care, ?20.9; treatment effect, ?15.2; 95% CI, ?18.5. to ?11.8). These differences narrowed somewhat at 2 years: bodily pain (mean change: surgery, 42.6 vs nonoperative care, 32.4; treatment effect, 10.2; 95% CI, 5.9-14.5), physical function (mean change: surgery, 43.9 vs nonoperavtive care 31.9; treatment effect, 12.0; 95% CI; 7.9-16.1), and Oswestry Disability Index (mean change: surgery ?37.6 vs nonoperative care ?24.2; treatment effect, ?13.4; 95% CI, ?17.0 to ?9.7). Conclusions Patients with persistent sciatica from lumbar disk herniation improved in both operated and usual care groups. Those who chose operative intervention reported greater improvements than patients who elected nonoperative care. However, nonrandomized comparisons of self-reported outcomes are subject to potential confounding and must be interpreted cautiously. Trial Registration clinicaltrials.gov Identifier: NCT00000410 PMID:17119141

  11. Histological analysis of surgical lumbar intervertebral disc tissue provides evidence for an association between disc degeneration and increased body mass index

    PubMed Central

    2011-01-01

    Background Although histopathological grading systems for disc degeneration are frequently used in research, they are not yet integrated into daily care routine pathology of surgical samples. Therefore, data on histopathological changes in surgically excised disc material and their correlation to clinical parameters such as age, gender or body mass index (BMI) is limited to date. The current study was designed to correlate major physico-clinical parameters from a population of orthopaedic spine center patients (gender, age and BMI) with a quantitative histologic degeneration score (HDS). Methods Excised lumbar disc material from 854 patients (529 men/325 women/mean age 56 (15-96) yrs.) was graded based on a previously validated histologic degeneration score (HDS) in a cohort of surgical disc samples that had been obtained for the treatment of either disc herniation or discogenic back pain. Cases with obvious inflammation, tumor formation or congenital disc pathology were excluded. The degree of histological changes was correlated with sex, age and BMI. Results The HDS (0-15 points) showed significantly higher values in the nucleus pulposus (NP) than in the annulus fibrosus (AF) (Mean: NP 11.45/AF 7.87), with a significantly higher frequency of histomorphological alterations in men in comparison to women. Furthermore, the HDS revealed a positive significant correlation between the BMI and the extent of histological changes. No statistical age relation of the degenerative lesions was seen. Conclusions This study demonstrated that histological disc alterations in surgical specimens can be graded in a reliable manner based on a quantitative histologic degeneration score (HDS). Increased BMI was identified as a positive risk factor for the development of symptomatic, clinically significant disc degeneration. PMID:22087871

  12. 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

  13. Iliac Crest Herniation Secondary to Autogenous Bone Grafting Found on Osteopathic Examination.

    PubMed

    Ou, Christine J; Sternfeld, William C; Stausmire, Julie M

    2015-08-01

    Surgical repair of difficult or nonunion fractures is frequently performed with autogenous bone grafts, most commonly from the iliac crest. Complications from this procedure may include vessel injury, nerve injury, pelvic instability, bowel herniation, and ileus. The authors report a case of iliac crest herniation in a patient presenting with a small-bowel obstruction 2 years after anterior iliac crest graft harvest for an open reduction and internal fixation repair of a right humeral shaft fracture. An emergency operation revealed that the right colon had herniated through an opening in the right iliac crest. The appendix had adhered to new osseous bone formed postoperatively, requiring an appendectomy. The hernia defect was successfully repaired with polypropylene mesh. A high index of suspicion for graft site herniation is needed for patients with a history of iliac crest bone grafting who present with symptoms of abdominal pain, flank or hip pain, ileus, or small-bowel obstruction. PMID:26214826

  14. Surgical vs Nonoperative Treatment for Lumbar Disk Herniation

    PubMed Central

    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

    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

  15. Extraperitoneal inguinoscrotal herniation of the ureter: a rare case of recurrence after hernia repair.

    PubMed

    Golgor, E; Stroszczynski, C; Froehner, M

    2009-01-01

    Inguinoscrotal herniation of the ureter is a rare finding with the potential for serious surgical complications. Two anatomic forms are defined. In the more common paraperitoneal variant, the herniating peritoneal sac drags the ureter and sometimes other abdominal structures with it. The uncommon variant--extraperitoneal inguinal herniais without a peritoneal sac and consists of the ureter and fat tissue. We report a case of extraperitoneal inguinoscrotal hernia possibly due to a prior inguinal hernia repair. PMID:19641370

  16. Spontaneous intercostal lung herniation complicated by rib fractures: a therapeutic dilemma

    PubMed Central

    Wani, Adil S.; Kalamkar, Prachi; Alhassan, Sulaiman; Farrell, Michael J.

    2015-01-01

    Lung herniation has been defined as a protrusion of lung tissue through its bounding structure. We present a case of spontaneous intercostal lung herniation following bouts of cough, which was complicated by multiple rib fractures, in which we had to adopt a non-surgical approach due to the clinical circumstance. Its understanding in the field of internal medicine is important as appropriate therapeutic judgment, and long-term follow-up is essential for full recovery. PMID:26719812

  17. Traumatic herniation of buccal fat pad in 1 year old child: case report and review of literature.

    PubMed

    Gadipelly, Srinivas; Sudheer, M V S; Neshangi, Srisha; Harsha, G; Reddy, Vijaybaskar

    2015-03-01

    Traumatic herniation of buccal fat pad (BFP) is very rare, usually seen in infants and young children ranging from 5 months to 12 years of age. Etiology will be blunt injury to buccal mucosa from foreign objects or trauma due to teeth and fall. The suckling activity in infants may also encourage the herniation following trauma. A minor injury or perforation to the buccal mucosa can cause herniation of BFP. The size of herniated mass is very large when compared to the size of the perforation. The history of trauma, absence of prolapse before the injury, its occurrence in infants and young children, specific anatomic sites and location of perforation in mucosa, histopathological appearance of adipose tissue are the characteristic features important for diagnosing the condition. The treatment options for the herniated BFP are usually excision. Alternative to excision is repositioning of the herniated fat in its anatomical location if noticed early. PMID:25848153

  18. Optical Disc Memory System

    NASA Astrophysics Data System (ADS)

    Imanaka, Ryoichi; Saimi, Tetsuo; Okazaki, Yukinori; Okino, Yoshihiro

    1983-11-01

    The video and the audio disc systems have been realized and the progress of optical disc memory systems allows the new products such as the video file system and the document file system. The optical disc memory system has a number of advantages compared with the current magnetic disc memory. These are the large recording capacity, the high recording density (10 to 100 times more than ordinary magnetic disc) and the contact free record and retrieval of the information, which eliminates the "Head Crush" problems and realizes the reliable information storage system. However, high recording density and small track pitches (usually 1.6--2.5 micron meters) increases the probability of error rate of recording infomation. Bit error rate (BER) of the recorded optical disc sometimes presents 10-4-10-5 Which is much higher than the magnetic disc. This high BER strongly depends on the production process. Optical disc is preformatted with the address information and with the tracks for infor-mation recording. The pregrooved disc used to be produced by the optical mastering process and the U-V replication process, which needs the very high-grade clean room and the expensive facilities. Process control of the laser cutting on the resist coated glass master is quite sensitive and must be treated with extreme care. When the large quantity of mass produced optical memory discs is supplied, a new mastering process would be needed. One of the solutions of this problem is the dry mastering process with a mechanical cutting system.

  19. Riboflavin crosslinked high-density collagen gel for the repair of annular defects in intervertebral discs: An in vivo study.

    PubMed

    Grunert, Peter; Borde, Brandon H; Towne, Sara B; Moriguchi, Yu; Hudson, Katherine D; Bonassar, Lawrence J; Härtl, Roger

    2015-10-15

    Open annular defects compromise the ability of the annulus fibrosus to contain nuclear tissue in the disc space, and therefore lead to disc herniation with subsequent degenerative changes to the entire intervertebral disc. This study reports the use of riboflavin crosslinked high-density collagen gel for the repair of annular defects in a needle-punctured rat-tail model. High-density collagen has increased stiffness and greater hydraulic permeability than conventional low-density gels; riboflavin crosslinking further increases these properties. This study found that treating annular defects with crosslinked high-density collagen inhibited the progression of disc degeneration over 18 weeks compared to untreated control discs. Histological sections of FITC-labeled collagen gel revealed an early tight attachment to host annular tissue. The gel was subsequently infiltrated by host fibroblasts which remodeled it into a fibrous cap that bridged the outer disrupted annular fibers and partially repaired the defect. This repair tissue enhanced retention of nucleus pulposus tissue, maintained physiological disc hydration, and preserved hydraulic permeability, according to MRI, histological, and mechanical assessments. Degenerative changes were partially reversed in treated discs, as indicated by an increase in nucleus pulposus size and hydration between weeks 5 and 18. The collagen gel appeared to work as an instant sealant and by enhancing the intrinsic healing capabilities of the host tissue. PMID:26116448

  20. Associations between Alpha Angle and Herniation Pit on MRI Revisited in 185 Asymptomatic Hip Joints

    PubMed Central

    Lee, Eunchae

    2015-01-01

    Objective To evaluate the association between alpha angle and herniation pit on MRI in asymptomatic hip joints and their associations with demographic variables. Materials and Methods Hip MRI of 185 asymptomatic hip joints of 105 adults (age 18 to 80 years) from September 2011 through December 2012 were retrospectively studied. Alpha angles were measured on oblique axial MR images by 2 observers. Herniation pit was determined by 1 observer. Size measures, prevalence, and statistical analyses were conducted regarding its association with age, gender, laterality (right or left hip). Intra- and inter-observer agreements were determined by intra-class correlation coefficient. Results The prevalence of herniation pit in asymptomatic hips was 21.6%. The range of alpha angle was 27.6-65.0 degrees. Seventeen and 16 out of 185 (9.1% and 8.6%) hip joints showed alpha angle of ? 55 degrees in first and second measurement sessions, respectively. There was no association between alpha angle ? 55 and presence of herniation pit. There was no association between alpha angle ? 55 and the size of herniation pit. Inter-observer agreement of alpha angle was 0.485 between first measurements of first vs. second observer, respectively. Intra-observer agreement of alpha angle was 0.654, respectively. Forty (21.6%) of 185 hip joints (35 of 105 patients, 33.3%) had herniation pit, with no difference according to age, gender, or laterality of hip joint. Conclusion There is no association between alpha angle ? 55 degrees and presence of herniation pit or demographic variables. PMID:26576122

  1. Bryan total disc arthroplasty: a replacement disc for cervical disc disease

    PubMed Central

    Wenger, Markus; Markwalder, Thomas-Marc

    2010-01-01

    Total disc arthroplasty is a new option in the treatment of cervical degenerative disc disease. Several types of cervical disc prostheses currently challenge the gold-standard discectomy and fusion procedures. This review describes the Bryan Cervical Disc System and presents the Bryan prosthesis, its indications, surgical technique, complications, and outcomes, as given in the literature. PMID:22915917

  2. Vacuum Technology

    SciTech Connect

    Biltoft, P J

    2004-10-15

    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.

  3. Magnetic resonance imaging on disc degeneration changes after implantation of an interspinous spacer and fusion of the adjacent segment

    PubMed Central

    Liu, Xiaokang; Liu, Yingjie; Lian, Xiaofeng; Xu, Jianguang

    2015-01-01

    The aim of the study was to investigate the changes of the lumbar intervertebral disc degeneration by magnetic resonance imaging (MRI) after the implantation of interspinous device and the fusion of the adjacent segment. A total of 62 consecutive patients suffering L5/S1 lumbar disc herniation (LDH) with concomitant disc space narrowing or low-grade instability up to 5 mm translational slip in L5/S1 level were treated with lumbar interbody fusion (LIF) via posterior approach. Thirty-four of these patients (Coflex group) received an additional implantation of the interspinous spacer device (Coflex™) in the level L4/L5, while the rest of 28 patients (fusion group) underwent the fusion surgery alone. Clinical and radiographic examinations were performed at pre- and postoperative visits to compare the clinical outcomes and the changes of the L4/L5 vertebral disc degeneration on MRI in both Coflex and fusion group. Although both Coflex and fusion group showed improvements of the clinical outcomes assessed by the Oswestry Disability Index (ODI) after surgery, patients in Coflex group had more significant amelioration (P < 0.05) compared to fusion group. During follow up, the postoperative disc degeneration changes in Coflex group assessed by the relative signal intensity (RSI) differed from those in fusion group (P < 0.05). The supplemental implantation of Coflex™ after the fusion surgery could delay the disc degeneration of the adjacent segment. PMID:26131210

  4. Vacuum mechatronics

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

    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.

  5. Vacuum Virtues

    ERIC Educational Resources Information Center

    Rathey, Allen

    2007-01-01

    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…

  6. Correction of true periorbital fat herniation in cosmetic lower lid blepharoplasty.

    PubMed

    Sachs, M E; Bosniak, S L

    1986-01-01

    The presence of puffy, baggy lower eyelids is one of the first signs of the aging face. Baggy eyelids can result from excessive eyelid skin, hypertrophied orbicularis muscle, and/or periorbital fat herniation. An exact diagnosis of which components are contributing to the problem must be made in the preoperative period so that proper correction can be made during surgery. The concept of true periorbital fat herniation in the causation of baggy lower eyelids is presented. The surgical correction of this anatomic defect involves identification and approximation of the dehiscent orbital septum to the capsulopalpebral ligament. Thirty-five patients who presented with true lower eyelid fat herniation and who underwent direct suture repair are reviewed. PMID:3526832

  7. Intervertebral disc degeneration.

    PubMed

    Fraser, R D; Osti, O L; Vernon-Roberts, B

    1993-03-01

    Disc degeneration in the human spine is a complex phenomenon characterised by biochemical change in the nucleus pulposus and inner annulus and the formation of clefts and fissures radiating from the central area of the disc towards the periphery. In addition, and probably independent of these phenomena, discrete defects in the outer annular attachement are seen which are likely to be due to mechanical stress and failure. The presence of stress tears in disc tissue and their failure to heal can initiate or accelerate the degeneration of the central component of the intervertebral disc. We postulate that discogenic pain may be linked to damage to the outer portion of the annulus fibrosus. Although it would seem logical to assume that discs with sustained high intradiscal pressure would be more prone to pain referred in the outer annular layers because of higher tensile strain, analysis of prospective studies has failed to confirm a relationship between typical pain reproduction at discography and high pressure values. It is concluded that, at present, the only consistent morphological changes present in patients with pain reproduction at discography are the presence of various annular defects involving the outer layers. Whether nerve ingrowth during attempts at repair of these defects is a consistent feature remains to be established. PMID:20054919

  8. Revival of the Jumping Disc

    ERIC Educational Resources Information Center

    Ucke, C.; Schlichting, H-J.

    2009-01-01

    Snap discs made of bimetal have many technical applications as thermostats. Jumping discs are a toy version of such snap discs. Besides giving technical information, we describe physical investigations. We show especially how, through simple measurements and calculations, you can determine the initial speed ([approximately equal to]3.5 m…

  9. The DISC Quotient

    NASA Astrophysics Data System (ADS)

    Elliott, John R.; Baxter, Stephen

    2012-09-01

    D.I.S.C: Decipherment Impact of a Signal's Content. The authors present a numerical method to characterise the significance of the receipt of a complex and potentially decipherable signal from extraterrestrial intelligence (ETI). The purpose of the scale is to facilitate the public communication of work on any such claimed signal, as such work proceeds, and to assist in its discussion and interpretation. Building on a "position" paper rationale, this paper looks at the DISC quotient proposed and develops the algorithmic steps and comprising measures that form this post detection strategy for information dissemination, based on prior work on message detection, decipherment. As argued, we require a robust and incremental strategy, to disseminate timely, accurate and meaningful information, to the scientific community and the general public, in the event we receive an "alien" signal that displays decipherable information. This post-detection strategy is to serve as a stepwise algorithm for a logical approach to information extraction and a vehicle for sequential information dissemination, to manage societal impact. The "DISC Quotient", which is based on signal analysis processing stages, includes factors based on the signal's data quantity, structure, affinity to known human languages, and likely decipherment times. Comparisons with human and other phenomena are included as a guide to assessing likely societal impact. It is submitted that the development, refinement and implementation of DISC as an integral strategy, during the complex processes involved in post detection and decipherment, is essential if we wish to minimize disruption and optimize dissemination.

  10. The Teddy Bears' Disc.

    ERIC Educational Resources Information Center

    Laurillard, Diana

    1985-01-01

    Reports an evaluation of the Teddy Bear disc, an interactive videodisc developed at the Open University for a second-level course in metallurgy and materials technology. Findings from observation of students utilizing the videodisc are reviewed; successful design features and design problems are considered; and development costs are outlined. (MBR)

  11. Warp Propagation in Astrophysical Discs

    NASA Astrophysics Data System (ADS)

    Nixon, Chris; King, Andrew

    Astrophysical discs are often warped, that is, their orbital planes change with radius. This occurs whenever there is a non-axisymmetric force acting on the disc, for example the Lense-Thirring precession induced by a misaligned spinning black hole, or the gravitational pull of a misaligned companion. Such misalignments appear to be generic in astrophysics. The wide range of systems that can harbour warped discs—protostars, X-ray binaries, tidal disruption events, quasars and others—allows for a rich variety in the disc's response. Here we review the basic physics of warped discs and its implications.

  12. Warp propagation in astrophysical discs

    E-print Network

    Nixon, Chris

    2015-01-01

    Astrophysical discs are often warped, that is, their orbital planes change with radius. This occurs whenever there is a non-axisymmetric force acting on the disc, for example the Lense-Thirring precession induced by a misaligned spinning black hole, or the gravitational pull of a misaligned companion. Such misalignments appear to be generic in astrophysics. The wide range of systems that can harbour warped discs - protostars, X-ray binaries, tidal disruption events, quasars and others - allows for a rich variety in the disc's response. Here we review the basic physics of warped discs and its implications.

  13. Efficacy of Percutaneous Epidural Neuroplasty Does Not Correlate with Dural Sac Cross-Sectional Area in Single Level Disc Disease

    PubMed Central

    Ji, Gyu Yeul; Oh, Chang Hyun; Moon, Bongju; Choi, Seung Hyun; Yoon, Young Sul; Kim, Keung Nyun

    2015-01-01

    Purpose Percutaneous epidural neuroplasty (PEN) is a minimally invasive treatment. The efficacy of PEN has been relatively well investigated; however, the relationship between the clinical effectiveness of PEN and the severity of spinal canal stenosis by disc material has not yet been established. The purpose of this study was to compare clinical outcomes of PEN according to the dural sac cross-sectional area in single level disc disease. Materials and Methods This study included 363 patients with back pain from single level disc disease with and without radiculopathy. Patients were categorized into groups according to spinal canal compromise by disc material: Category 1, less or more than 50%; and Category 2, three subgroups with lesser than a third, between a third and two thirds, and more than two thirds. Clinical outcomes were assessed according to the Visual Analog Scale (VAS) score for back pain and leg pain and Odom's criteria at 1, 3, 6, 12, and 24 months after treatment. Results The demographic data showed no difference between groups according to spinal canal compromise by disc material except age (older age correlated with more spinal canal compromise). The dural sac cross-sectional area did not correlate with the VAS scores for back and leg pain after PEN in single level disc disease in Groups 1 and 2. Odom's criteria after PEN were also not different according to dural sac cross-sectional area by disc material. Conclusion PEN is an effective procedure in treating single level lumbar disc herniation without affecting dural sac cross-sectional area. PMID:25837174

  14. Biomechanics of Disc Degeneration

    PubMed Central

    Palepu, V.; Kodigudla, M.; Goel, V. K.

    2012-01-01

    Disc degeneration and associated disorders are among the most debated topics in the orthopedic literature over the past few decades. These may be attributed to interrelated mechanical, biochemical, and environmental factors. The treatment options vary from conservative approaches to surgery, depending on the severity of degeneration and response to conservative therapies. Spinal fusion is considered to be the “gold standard” in surgical methods till date. However, the association of adjacent level degeneration has led to the evolution of motion preservation technologies like spinal arthroplasty and posterior dynamic stabilization systems. These new technologies are aimed to address pain and preserve motion while maintaining a proper load sharing among various spinal elements. This paper provides an elaborative biomechanical review of the technologies aimed to address the disc degeneration and reiterates the point that biomechanical efficacy followed by long-term clinical success will allow these nonfusion technologies as alternatives to fusion, at least in certain patient population. PMID:22745914

  15. Mechanotransduction in intervertebral discs

    PubMed Central

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

    2014-01-01

    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

  16. Apsidal precession, disc breaking and viscosity in warped discs

    NASA Astrophysics Data System (ADS)

    Nealon, Rebecca; Nixon, Chris; Price, Daniel J.; King, Andrew

    2016-01-01

    We demonstrate the importance of general relativistic apsidal precession in warped black hole accretion discs by comparing three-dimensional smoothed particle hydrodynamic simulations in which this effect is first neglected, and then included. If apsidal precession is neglected, we confirm the results of an earlier magnetohydrodynamic simulation which made this assumption, showing that at least in this case the ? viscosity model produces very similar results to those of simulations where angular momentum transport is due to the magnetorotational instability. Including apsidal precession significantly changes the predicted disc evolution. For moderately inclined discs thick enough that tilt is transported by bending waves, we find a disc tilt which is non-zero at the inner disc edge and oscillates with radius, consistent with published analytic results. For larger inclinations, we find disc breaking.

  17. Apsidal precession, disc breaking and viscosity in warped discs

    E-print Network

    Nealon, Rebecca; Price, Daniel J; King, Andrew

    2015-01-01

    We demonstrate the importance of general relativistic apsidal precession in warped black hole accretion discs by comparing three - dimensional smoothed particle hydrodynamic simulations in which this effect is first neglected, and then included. If apsidal precession is neglected, we confirm the results of an earlier magnetohydrodynamic simulation which made this assumption, showing that at least in this case the $\\alpha$ viscosity model produces very similar results to those of simulations where angular momentum transport is due to the magnetorotational instability. Including apsidal precession significantly changes the predicted disc evolution. For moderately inclined discs thick enough that tilt is transported by bending waves, we find a disc tilt which is nonzero at the inner disc edge and oscillates with radius, consistent with published analytic results. For larger inclinations we find disc breaking.

  18. Polarimetric microlensing of circumstellar discs

    NASA Astrophysics Data System (ADS)

    Sajadian, Sedighe; Rahvar, Sohrab

    2015-12-01

    We study the benefits of polarimetry observations of microlensing events to detect and characterize circumstellar discs around the microlensed stars located at the Galactic bulge. These discs which are unresolvable from their host stars make a net polarization effect due to their projected elliptical shapes. Gravitational microlensing can magnify these signals and make them be resolved. The main aim of this work is to determine what extra information about these discs can be extracted from polarimetry observations of microlensing events in addition to those given by photometry ones. Hot discs which are closer to their host stars are more likely to be detected by microlensing, owing to more contributions in the total flux. By considering this kind of discs, we show that although the polarimetric efficiency for detecting discs is similar to the photometric observation, but polarimetry observations can help to constraint the disc geometrical parameters e.g. the disc inner radius and the lens trajectory with respect to the disc semimajor axis. On the other hand, the time-scale of polarimetric curves of these microlensing events generally increases while their photometric time-scale does not change. By performing a Monte Carlo simulation, we show that almost four optically thin discs around the Galactic bulge sources are detected (or even characterized) through photometry (or polarimetry) observations of high-magnification microlensing events during 10-yr monitoring of 150 million objects.

  19. Vacuum Waves

    E-print Network

    Paul S. Wesson

    2012-12-11

    As an example of the unification of gravitation and particle physics, an exact solution of the five-dimensional field equations is studied which describes waves in the classical Einstein vacuum. While the solution is essentially 5D in nature, the waves exist in ordinary 3D space, and may provide a way to test for an extra dimension.

  20. Enclosed rotary disc air pulser

    DOEpatents

    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

    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.

  1. Numbered nasal discs for waterfowl

    USGS Publications Warehouse

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

    1964-01-01

    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.

  2. Fournier's gangrene secondary to an acutely inflamed appendix herniating into the deep inguinal ring.

    PubMed

    Sarmah, Piyush B; Khan, Mashuk; Zilvetti, Miguel

    2015-01-01

    Fournier's gangrene (FG) requires prompt recognition and management. We report the case of a 68-year-old man who presented with extensive pain and purple discolouration from the right iliac fossa to perineum. Computed tomography demonstrated gas within the right hemiscrotum extending into the inguinal canal and right buttock, with a right pelvic fluid and air collection. At debridement necrotic fluid was arising from the superficial inguinal ring so laparotomy was performed, revealing a grossly inflamed appendix herniating into the inguinal canal; a right hemicolectomy was performed. Unfortunately, the patient went into cardiac arrest and passed away on the operating table. Histological analysis demonstrated acute-on-chronic inflammation involving the appendix. The condition where appendicitis is implicated in FG is usually due to retroperitoneal rupture and tracking into the perineal spaces. This is the first case reported of an inflamed appendix herniating into the inguinal canal and thus causing FG. PMID:25829533

  3. Fournier's gangrene secondary to an acutely inflamed appendix herniating into the deep inguinal ring

    PubMed Central

    Sarmah, Piyush B.; Khan, Mashuk; Zilvetti, Miguel

    2015-01-01

    Fournier's gangrene (FG) requires prompt recognition and management. We report the case of a 68-year-old man who presented with extensive pain and purple discolouration from the right iliac fossa to perineum. Computed tomography demonstrated gas within the right hemiscrotum extending into the inguinal canal and right buttock, with a right pelvic fluid and air collection. At debridement necrotic fluid was arising from the superficial inguinal ring so laparotomy was performed, revealing a grossly inflamed appendix herniating into the inguinal canal; a right hemicolectomy was performed. Unfortunately, the patient went into cardiac arrest and passed away on the operating table. Histological analysis demonstrated acute-on-chronic inflammation involving the appendix. The condition where appendicitis is implicated in FG is usually due to retroperitoneal rupture and tracking into the perineal spaces. This is the first case reported of an inflamed appendix herniating into the inguinal canal and thus causing FG. PMID:25829533

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

    PubMed Central

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

    2014-01-01

    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

  5. Preparation of ormetoprim sulfadimethoxine medicated discs for disc diffusion assay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Romet (a blend of ormetoprim and sulfadimethoxine) is a typeA medicated article for the manufacture of medicated feed in the catfish industry. Recently, the commercial manufacture of ormetoprim–sulfadimethoxine susceptibility discs was discontinued. Ormetoprim–sulfadimethoxine discs were prepared at...

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

    PubMed Central

    2009-01-01

    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

  7. Persistent Atrial Fibrillation Related to a Congenital Pericardial Defect and Left Atrial Appendage Herniation

    PubMed Central

    Lee, Heemoon; Jeong, Dong Seop; Kim, In Sook; Park, Byung Jo

    2015-01-01

    Congenital pericardial defects (CPDs) are infrequent anomalies that are usually asymptomatic and are discovered incidentally during unrelated interventions. Here we report the case of a CPD with herniation of an enlarged left atrial appendage identified during total thoracoscopic ablation (TTA) for persistent atrial fibrillation (AF). The persistent AF was successfully treated with a hybrid procedure, in which TTA was followed by an electrophysiological study. PMID:26665114

  8. Against the Odds: Massive Lumbar Intradural Disk Herniation in the Elderly

    PubMed Central

    Orakcioglu, Berk; Dao Trong, Huy Philip; Jungk, Christine; Unterberg, Andreas

    2015-01-01

    Study Design?Case report. Objective?Presentation of an unusual case of an elderly patient with massive intradural disk herniation at the L2–L3 level. Methods?Clinical and imaging data are presented after obtaining informed consent from the patient. Results?A 90-year-old man suffering from sudden-onset neurogenic bladder dysfunction and lower back pain but no further neurologic deficits initially presented with magnetic resonance imaging and laboratory values suggestive of an intraspinal infection. However, intraoperative inspection proved the unexpected finding of a large intradural lumbar disk herniation at the L2–L3 level. Conclusions?Lumbar soft disk herniation to the intradural space is a rare event and has never been described in a patient over the age of 75. This case of a 90-year-old man with acute-onset bladder dysfunction underlines the necessity to consider this as a differential diagnosis in the case of a newly diagnosed intradural mass. PMID:26430608

  9. Incarcerated herniation of the cervical spinal cord after laminectomy for an ossification of the yellow ligament.

    PubMed

    Ohnishi, Yu-Ichiro; Iwatsuki, Koichi; Yoshimura, Kazuhiro; Ishihara, Masahiro; Yoshimine, Toshiki

    2010-07-01

    A 74-year-old man showed a spastic gait and myelopathy in both the hands. Computed tomography revealed an OPLL on C3 and C4, bony spurs on the dorsal side of C4-C6, and an OYL on C3 and C4. We scheduled a two-stage decompression for both the OPLL and OYL. First, we performed laminectomy on the C3-C6 segments and resected the OYL. We did not observe any dural tear or CSF leakage in the dura. The patient's neurological symptoms improved. After the laminectomy, his myelopathy recurred. Postoperative MRI showed a spinal cord herniation. We had the C3/4 anterior cervical disectomy and fusion as we planned. In addition, we performed a surgery to repair the damaged dura mater at the site of spinal cord herniation at the same second surgery. The integrity of the arachnoid membrane was preserved. The patient's myelopathy gradually improved. There have been no reports on postoperative neurological deterioration caused by spinal cord herniation associated with a dural defect at the laminectomy site, without dural tear in the surgery after the resection of a posteriorly located cervical OYL. The possibility of a dural defect in OYL cases should be considered when planning a laminectomy for the resection of the OYL. PMID:19937353

  10. High-mobility group box-1 gene, a potent proinflammatory mediators, is upregulated in more degenerated human discs in vivo and its receptor upregulated by TNF-? exposure in vitro.

    PubMed

    Gruber, Helen E; Hoelscher, Gretchen L; Bethea, Synthia; Ingram, Jane; Cox, Michael; Hanley, Edward N

    2015-06-01

    Mechanisms which control and enhance proinflammatory cytokine expression during human disc degeneration are still poorly understood. The high-mobility group box-1 gene (HMGB1) produces a protein which can itself act as a cytokine, or can function as a potent proinflammatory mediator. Little is known about expression of HMGB1 in the human disc. Since proinflammatory cytokines increase significantly during human disc degeneration, in this work we hypothesized that HMGB1 may show upregulation with advancing stages of degeneration, and upregulation in cells exposed to TNF-?. Immunohistochemistry was performed to confirm the presence of HMGB1 in the human disc, and human annulus cells were cultured and challenged with 10(3)pM TNF-? for 14days in 3D culture. Cells with positive HMGB1 immunolocalization were abundant in the outer annulus. Molecular analysis of cultured cells showed an 8-fold significant increase in HMGB1 expression in more degenerated Thompson grade V discs compared to healthier grade I/II discs (p=0.033). Human disc tissue was assessed in molecular studies. Herniated specimens showed a 6.3-fold significantly greater expression level than that seen in control specimens (p=0.001). In culture experiments, expression of the receptor to HMGB1, toll-like receptor 2, showed a 24-fold upregulation in vitro in cells exposed to TNF-? vs. controls (p=0.0003). PMID:25746662

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

    PubMed Central

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

    2014-01-01

    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

  12. Protoplanetary disc evolution and dispersal

    E-print Network

    Owen, James Edward

    2011-10-11

    to the formation of the reservoir of gas and dust from which planets will form: the protoplanetary disc. Protoplanetary discs are an inevitable outcome of star formation and their existence was postulated during the 18th century within the framework of the nebular... hypothesis. 1.1 The origin of protoplanetary discs In order to initiate the star formation process, the gas from which the star is going to form must sat- isfy a basic requirement: namely that the gravitational collapse can proceed unimpeded by the thermal...

  13. Interleukin-17 synergizes with IFN? or TNF? to promote inflammatory mediator release and intercellular adhesion molecule-1 (ICAM-1) expression in human intervertebral disc cells

    PubMed Central

    Gabr, Mostafa A.; Jing, Liufang; Helbling, Antonia R.; Sinclair, S. Michael; Allen, Kyle D.; Shamji, Mohammed F.; Richardson, William J.; Fitch, Robert D.; Setton, Lori A.; Chen, Jun

    2010-01-01

    Interleukin-17 (IL-17) is a cytokine recently shown to be elevated, along with interferon-? (IFN?) and tumor necrosis factor (TNF?), in degenerated and herniated intervertebral disc (IVD) tissues, suggesting a role for these cytokines in intervertebral disc disease. The objective of our study was to investigate the involvement of IL-17 and costimulants IFN? and TNF? in intervertebral disc pathology. Cells were isolated from anulus fibrosus and nucleus pulposus tissues of patients undergoing surgery for intervertebral disc degeneration or scoliosis. The production of inflammatory mediators, nitric oxide (NOx), prostaglandin E2 (PGE2) and interleukin-6 (IL-6), as well as intercellular adhesion molecule (ICAM-1) expression, were quantified for cultured cells following exposure to IL-17, IFN? and TNF?. Intervertebral disc cells exposed to IL-17, IFN? or TNF? showed a remarkable increase in inflammatory mediator release and ICAM-1 expression (GLM and ANOVA, p<0.05). Addition of IFN? or TNF? to IL-17 demonstrated a synergistic increase in inflammatory mediator release, and a marked increase in ICAM-1 expression. These findings suggest that IVD cells not only respond with a catabolic phenotype to IL-17 and costimulants IFN? and TNF?, but also express surface ligands with consequent potential to recruit additional lymphocytes and immune cells to the IVD microenvironment. IL-17 may be an important regulator of inflammation in the IVD pathologies. PMID:20665551

  14. Enlivening Physics, a Local Video Disc Project.

    ERIC Educational Resources Information Center

    McInerney, M.

    1989-01-01

    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)

  15. On total disc replacement.

    PubMed

    Berg, Svante

    2011-02-01

    Low back pain consumes a large part of the community's resources dedicated to health care and sick leave. Back disorders also negatively affect the individual leading to pain suffering, decreased quality-of-life and disability. Chronic low back pain (CLBP) due to degenerative disc disease (DDD) is today often treated with fusion when conservative treatment has failed and symptoms are severe. This treatment is as successful as arthroplasty is for hip arthritis in restoring the patient's quality of life and reducing disability. Even so, there are some problems with this treatment, one of these being recurrent CLBP from an adjacent segment (ASD) after primarily successful surgery. This has led to the development of alternative surgical treatments and devices that maintain or restore mobility, in order to reduce the risk for ASD. Of these new devices, the most frequently used are the disc prostheses used in Total Disc Replacement (TDR). This thesis is based on four studies comparing total disc replacement with posterior fusion. The studies are all based on a material of 152 patients with DDD in one or two segments, aged 20-55 years that were randomly treated with either posterior fusion or TDR. The first study concerned clinical outcome and complications. Follow-up was 100% at both one and two years. It revealed that both treatment groups had a clear benefit from treatment and that patients with TDR were better in almost all outcome scores at one-year follow-up. Fusion patients continued to improve during the second year. At two-year follow-up there was a remaining difference in favour of TDR for back pain. 73% in the TDR group and 63% in the fusion group were much better or totally pain-free (n.s.), while twice as many patients in the TDR group were totally pain free (30%) compared to the fusion group (15%). Time of surgery and total time in hospital were shorter in the TDR group. There was no difference in complications and reoperations, except that seventeen of the patients in the fusion group were re-operated for removal of their implants. The second study concerned sex life and sexual function. TDR is performed via an anterior approach, an approach that has been used for a long time for various procedures on the lumbar spine. A frequent complication reported in males when this approach is used is persistent retrograde ejaculation. The TDR group in this material was operated via an extra-peritoneal approach to the retroperitoneal space, and there were no cases of persistent retrograde ejaculation. There was a surprisingly high frequency of men in the fusion group reporting deterioration in ability to have an orgasm postoperatively. Preoperative sex life was severely hampered in the majority of patients in the entire material, but sex life underwent a marked improvement in both treatment groups by the two-year follow-up that correlated with reduction in back pain. The third study was on mobility in the lumbar spinal segments, where X-rays were taken in full extension and flexion prior to surgery and at two-year follow-up. Analysis of the films showed that 78% of the patients in the fusion group reached the surgical goal (non-mobility) and that 89% of the TDR patients maintained mobility. Preoperative disc height was lower than in a normative database in both groups, and remained lower in the fusion group, while it became higher in the TDR group. Mobility in the operated segment increased in the TDR group postoperatively. Mobility at the rest of the lumbar spine increased in both treatment groups. Mobility in adjacent segments was within the norm postoperatively, but slightly larger in the fusion group. In the fourth study the health economics of TDR vs Fusion was analysed. The hospital costs for the procedure were higher for patients in the fusion group compared to the TDR group, and the TDR patients were on sick-leave two months less. In all, these studies showed that the results in the TDR group were as good as in the fusion group. Patients are more likely to be totally pain-free when treated with TDR compared to fusion

  16. Difficult diagnosis: internal herniation of the terminal ileum through the foramen of Winslow into the lesser sac.

    PubMed

    Nazarian, Scarlet; Clegg, Daisy; Chang, Sebastian; Kuriakose, John

    2015-01-01

    Herniation of the bowel through the foramen of Winslow is rare and accounts for 8% of all internal herniae. It typically presents clinically and biochemically as small bowel obstruction. It carries a high mortality as diagnosis is often delayed, despite bowel strangulation, as clinical signs are not typical and imaging may not be diagnostic. In the case presented here, a healthy 25-year-old man was admitted with sudden onset right-sided abdominal and back pain. He denied vomiting, and had opened his bowels. His bloods were normal and venous lactate <2; CT was not diagnostic. At laparotomy, he was found to have internal herniation of the terminal ileum through the foramen of Winslow, which was gangrenous and required resection. This paper discusses the difficulty in diagnosing internal herniation and poses the question as to whether we are too dependent on CT findings in the setting of an acute abdomen. PMID:26682837

  17. Cervical radiculopathy caused by neural foraminal migration of a herniated calcified intervertebral disk in childhood: a case report.

    PubMed

    Park, Sung Min; Kim, Eun-Sang; Sung, Duk Hyun

    2005-11-01

    Childhood intervertebral disk calcification is a rare clinical entity. Although its clinical course is usually benign, nerve root irritation or spinal cord compression can occasionally occur. We present the clinical and radiologic findings of a 9-year-old boy with cervical radiculopathy due to a herniated calcified intervertebral disk, which developed suddenly after swimming for 1 hour. Radiologic findings indicated that a calcified nucleus pulposus at the C6-7 level herniated into the spinal canal and migrated far into the right C6-7 neural foramen. Surgical management was performed 8 weeks after the onset of symptoms, because the initial presenting symptoms persisted despite conservative treatment. In children, calcified intervertebral disks can cause cervical radiculopathy that requires surgical management when they herniate and migrate far into the neural foramen. PMID:16271574

  18. Disc Golf, a Growing Sport

    PubMed Central

    Nelson, Joseph T.; Jones, Richard E.; Runstrom, Michael; Hardy, Jolene

    2015-01-01

    Background Disc golf is a sport played much like traditional golf, but rather than using a ball and club, players throw flying discs with various throwing motions. It has been played by an estimated 8 to 12 million people in the United States. Like all sports, injuries sustained while playing disc golf are not uncommon. Although formalized in the 1970s, it has grown at a rapid pace; however, disc golf–related injuries have yet to be described in the medical literature. Purpose To describe the most common injuries incurred by disc golf players while comparing the different types of throwing styles. Study Design Descriptive epidemiology study. Methods The data in this study were collected from 883 disc golf players who responded to an online survey collected over a 1-month period. Respondents answered 49 questions related to demographics, experience, style of play, and injury details. Using a chi-square analysis, common injuries sustained in players using backhand and forehand throwing styles were compared. Results More than 81% of respondents stated that they had sustained an injury playing disc golf, including injuries to the elbow (n = 325), shoulder (n = 305), back (n = 218), and knee (n = 199). The injuries were most commonly described as a muscle strain (n = 241), sprain (n = 162), and tendinitis (n = 145). The type of throw primarily used by players varied, with 86.2% using backhand, 12.7% using forehand, and 1.1% using an overhead throw. Players using a forehand throw were more likely to sustain an elbow injury (P = .014). Many players (n = 115) stated they had undergone surgery due to a disc golf–related injury, with the most common surgeries including meniscal, shoulder, spine, and foot/ankle surgeries. Conclusion The majority of surveyed disc golfers sustained at least 1 injury while playing disc golf, with many requiring surgery. The types of injuries sustained by players varied by the types of throw primarily used. As the sport of disc golf continues to expand, health professionals should be aware of injuries sustained, with future studies focusing on injury prevention and education strategies. PMID:26665099

  19. Marathon related death due to brainstem herniation in rehydration-related hyponatraemia: a case report

    PubMed Central

    Petzold, Axel; Keir, Geoffrey; Appleby, Ian

    2007-01-01

    Introduction Identifying marathon runners at risk of neurological deterioration at the end of the race (within a large cohort complaining of exhaustion, dehydration, nausea, headache, dizziness, etc.) is challenging. Here we report a case of rehydration-related hyponatraemia with ensuing brain herniation. Case presentation We report the death of runner in his 30's who collapsed in the recovery area following a marathon. Following rehydration he developed a respiratory arrest in the emergency room. He was found to be hyponatraemic (130 mM). A CT brain scan showed severe hydrocephalus and brain stem herniation. Despite emergency insertion of an extraventricular drain, he was tested for brainstem death the following morning. Funduscopy demonstrated an acute-on-chronic papilledema; CSF spectrophotometry did not reveal any trace of oxyhemoglobin or bilirubin, but ferritin levels were considerably raised (530 ng/mL, upper reference value 12 ng/mL), consistent with a previous bleed. Retrospectively it emerged that the patient had suffered from a thunderclap headache some months earlier. Subsequently he developed morning headaches and nausea. This suggests that he may have suffered from a subarachnoid haemorrhage complicated by secondary hydrocephalus. This would explain why in this case the relatively mild rehydration-related hyponatremia may have caused brain swelling sufficient for herniation. Conclusion Given the frequency of hyponatraemia in marathon runners (serum Na <135 mM in about 13%), and the non-specific symptoms, we discuss how a simple screening test such as funduscopy may help to identify those who require urgent neuroimaging. PMID:18163909

  20. Intracranial hydatid cyst is a rare cause of midbrain herniation: A case report and literature review

    PubMed Central

    Duransoy, Yusuf Kurtulu?; Mete, Mesut; Barutçuo?lu, Mustafa; Ünsal, Ülkün Ünlü; Selçuki, Mehmet

    2013-01-01

    Hydatid disease is a parasitic infection affecting the brain in about 2% of the cases. Brain involvement is most commonly observed in children. Here, we report a 13-year-old male patient who presented with headache, nausea, and vomiting. Before cranial computed tomography (CT) was performed, the patient had generalized epileptic seizures. He was disoriented, and had anisocoria with dilatation of the right pupilla. CT showed a cystic lesion of 10-cm diameter in the right temporoparietal region that had caused a shift of the midline structures to the contralateral side; an urgent operation was performed as there were signs of midbrain herniation. PMID:24470819

  1. Recurrent pseudoaneurysm of the left ventricle with subcutaneous herniation into the chest wall. A case report.

    PubMed Central

    Rao, M S; Vaijyanath, P; Taneja, K; Dubey, B; Manchanda, S C; Venugopal, P

    1998-01-01

    Pseudoaneurysm of the left ventricle is rare, and recurrence is extremely rare. We report the case of a 62-year-old man who presented at our hospital with a painless pulsatile swelling in the left breast. He had undergone coronary artery bypass grafting and left-ventricular aneurysmectomy 14 years earlier. On investigation, the swelling was diagnosed to be a pseudoaneurysm of the left ventricle with subcutaneous herniation. The extreme rarity of this condition prompted us to report the case. The investigative techniques and the surgical strategy are discussed. Images PMID:9885110

  2. Management of post-goniopuncture iris herniation: a two-step procedure.

    PubMed

    Martín-Moro, Julio González; Miguel, Yolanda Fernández

    2014-06-01

    A 38-year-old male presented to the emergency room suffering acute pain in his left eye. Two months before he had been submitted to uneventful non-penetrating deep sclerectomy and one month before to YAG-laser goniopuncture. Examination showed iris herniation into the trabeculo-descemet's window. Surgical reduction was carried out through a peripheral corneal incision, and a large air bubble was injected into the anterior chamber. Four days later a wide laser peripheral iridotomy was performed. This technique can transform a non-penetrating technique into a full-trabeculectomy, without reopening the superficial flap. PMID:23740144

  3. Viscoelastic Disc Arthroplasty Provides Superior Back and Leg Pain Relief in Patients with Lumbar Disc Degeneration Compared to Anterior Lumbar Interbody Fusion

    PubMed Central

    Rischke, Burkhard; Smith, Eric

    2015-01-01

    Background Lumbar disc degeneration (LDD) is one of the most frequently diagnosed spinal diseases. The symptoms these disorders cause are anticipated to increase as the population in Western countries ages. Purpose Compare back and leg pain alleviation in patients with LDD and a viscoelastic disc prosthesis documented in the SWISSspine registry versus patients with anterior lumbar interbody fusion documented in the Spine Tango registry. Study Design Prospectively collected clinical and outcome data in two independent spine registries. Outcome Measures were back and leg pain relief on 0 to 10 numerical rating scales. Materials and Methods The analysis included a single surgeon series of 48 patients with viscoelastic total disc replacement (VTDR) from the SWISSspine registry which were compared to 131 patients with anterior lumbar interbody fusion (ALIF) from the Spine Tango registry. Two linear multivariate regression models were built to assess the associations of patient characteristics with back and leg pain relief. The following covariates were included in the models: patient age and sex, disc herniation as additional diagnosis, number of treated segments, level of treated segment, treatment type (VTDR, ALIF), preoperative back and leg pain levels and follow-up interval. Results Both models showed VTDR to be associated with significantly higher back (2.76 points; 95% confidence interval (CI) 1.78 - 3.73; p < 0.001) and leg pain (2.12 points; 95% CI 1.12 to 3.13; p < 0.001) relief than ALIF. Other influential factors for higher back pain relief were female sex compared with male sex (1.03 additional points; 95% CI 0.27 to 1.78; p = 0.008), monosegmental surgery compared with bisegmental surgery (1.02 additional points; 95% CI 0.21 to 1.83; p = 0.014), and higher back pain at baseline (0.87 points additional pain relief per level of preoperative back pain; 95% CI 0.70 to 1.03; p < 0.001). Other influential factors for leg pain relief were monosegmental surgery (0.93 additional points; 95% CI 0.10 to 1.77; p = 0.029) and higher leg pain at baseline (0.83 points additional pain relief per level of preoperative leg pain; 95% CI 0.70 to 0.96). In both models the L3/4 segment showed 2.36 points (95% CI -4.27 to -0.45; p = 0.016) and 3.69 points (95% CI -5.66 to -1.71; p < 0.001) less pain relief than L5/S1. Discussion Significantly higher back and leg pain relief were observed after viscoelastic total disc replacement in comparison with anterior lumbar interbody fusion. The new less rigid materials used in the second generation total disc replacements (TDRs) may make artificial disc replacement an increasingly attractive option for patients with degenerative lumbar disc disease. Further controlled and long-term follow-up studies are required for more detailed comparisons of the outcomes of these types of disc implants. The Freedom Lumbar Disc is limited by U.S. federal law to investigational use only. PMID:26196033

  4. THE VACUUM/STEAM/VACUUM PROCESS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Vacuum/Steam/Vacuum surface intervention pilot plant process was developed. The process was developed for chicken, hot dogs, fruits and vegetables, and catfish. Optimum process conditions were determined as nominally, 138 C saturated steam, vacuum and steam times of 0.1 s except that the final...

  5. Loss and re-adaptation of lumbar intervertebral disc water signal intensity after prolonged bedrest.

    PubMed

    Kordi, M; Belavý, D L; Armbrecht, G; Sheikh, A; Felsenberg, D; Trudel, G

    2015-09-01

    The adaptation and re-adaptation process of the intervertebral disc (IVD) to prolonged bedrest is important for understanding IVD physiology and IVD herniations in astronauts. Little information is available on changes in IVD composition. In this study, 24 male subjects underwent 60-day bedrest and In/Out Phase magnetic resonance imaging sequences were performed to evaluate IVD shape and water signal intensity. Scanning was performed before bedrest (baseline), twice during bedrest, and three, six and twenty-four months after bedrest. Area, signal intensity, average height, and anteroposterior diameter of the lumbar L3/4 and L4/5 IVDs were measured. At the end of bedrest, disc height and area were significantly increased with no change in water signal intensity. After bedrest, we observed reduced IVD signal intensity three months (p=0.004 versus baseline), six months (p=0.003 versus baseline), but not twenty-four months (p=0.25 versus baseline) post-bedrest. At these same time points post-bedrest, IVD height and area remained increased. The reduced lumbar IVD water signal intensity in the first months after bedrest implies a reduction of glycosaminoglycans and/or free water in the IVD. Subsequently, at two years after bedrest, IVD hydration status returned towards pre-bedrest levels, suggesting a gradual, but slow, re-adaptation process of the IVD after prolonged bedrest. PMID:26350949

  6. Papilledema and optic disc pit: The association of two pathologies in one patient.

    PubMed

    Galvez-Ruiz, Alberto; Ghazi, Nicola; Ruhaily, Yasir

    2012-10-01

    Histologically, optic disc pit (ODP) is described as a small congenital defect in the cribriform plate where a herniation of the dysplastic retina extends to the subarachnoid space in the optic nerve, which is surrounded by a layer of collagen-rich tissue. Approximately 25-75% of cases are complicated by optic disc pit maculopathy (ODPM). The pathogenesis of maculopathies associated with ODP has not been fully elucidated. We present an unusual case of a patient with a history of papilledema secondary to a fronto-temporal meningioma. The patient underwent a successful surgical intervention with resolution of the papilledema 15 years before the detection of an ODP that was associated with retinal detachment in the macular region. Several studies have reported on the importance of intracranial pressure in the development of maculopathies associated with ODP. During the period of intracranial hypertension and papilledema in our patient, the hernia sac that was associated with ODP may have been small, which would have decreased the chances of developing a maculopathy that was associated with OPD. PMID:23961031

  7. Experimental Studies of Spray Deposition on a Flat Surface in a Vacuum Environment

    NASA Technical Reports Server (NTRS)

    Golliher, Eric L.; Yao, S. C.

    2015-01-01

    Cooling of spacecraft components in the space environment is an on-going research effort. The electronics used in modern spacecraft are always changing and the heat flux is increasing. New, one-of-a-kind missions require new approaches to thermal control. In this research, under vacuum conditions, a pulsed water spray impinged on a small disc, while a high speed data acquisition system recorded the temperature histories of this copper disc. The water droplets froze quickly and accumulated on the disc as the spray continued. After the spray stopped, the frozen water that remained on the disc then sublimated into the vacuum environment and cooled the disc. This paper examines two important aspects of this process: 1) the difference in spray start up and shutdown in a vacuum environment versus in a standard atmospheric pressure environment, and 2) the water utilization efficiency in a vacuum environment due to the effects of drop trajectories and drop bouncing on the surface. Both phenomena play a role during spray cooling in a vacuum. This knowledge should help spacecraft designers plan for spray cooling as an option to cool spacecraft electronics, human metabolic generated heat, and heat from other sources.

  8. Background variables (medical history, anthropometric and biological factors) in relation to the outcome of lumbar disc surgery.

    PubMed

    Graver, V; Ljunggren, A E; Loeb, M; Haaland, A K; Lie, H; Magnaes, B

    1998-12-01

    In a prospective cohort study 122 patients with herniated intervertebral lumbar disc and no previous low back surgery preoperatively were assessed regarding medical history, anthropometric and biological background variables. The outcome of surgery (traditional methods) was evaluated one year postoperatively, mainly using a composite Clinical Overall Score (COS), including pain intensity, physical signs, functional capacity and analgesics. Return to work was also assessed. In regression analyses, low body height, high values of weight and body mass index, as well as long duration of sickness absence were shown to be significantly related to a poor outcome, as evaluated by the COS. However, after controlling for modifying effects of previously determined predictive fibrinolytic and psychological variables, the background variables lost their significance. Female sex, low stature, long duration of sickness absence and physically strenuous work activities were statistically significantly related to lower frequencies of return to work. PMID:9825386

  9. Treatment of localized neuropathic pain after disk herniation with 5% lidocaine medicated plaster

    PubMed Central

    Likar, Rudolf; Kager, Ingo; Obmann, Michael; Pipam, Wolfgang; Sittl, Reinhard

    2012-01-01

    Objective To assess treatment with the 5% lidocaine medicated plaster for peripheral neuropathic pain after disk herniation. Study design Case series, single center, retrospective data. Patients and methods Data of 23 patients treated for neuropathic pain with the lidocaine plaster for up to 24 months after a protrusion or prolapse of the cervical, thoracic, or lumbar vertebral disks were retrospectively analyzed. Changes in overall pain intensity, in intensity of different pain qualities and of allodynia and hyperalgesia were evaluated. Results Patients (14 female/nine male, mean age 53.5 ± 10.4 years) presented with radiating pain into the abdomen, back, neck, shoulder, or legs and feet with a mean pain intensity of 8.3 ± 1.5 on the 11-point Likert scale. Mean treatment duration was 7.6 months; 52% of the patients received lidocaine plaster as monotherapy. At the end of the observation, mean overall pain intensity had been reduced to 3.1 ± 1.8. All other parameters also improved. The treatment was well tolerated. Conclusion These results point to a safe and effective treatment approach with 5% lidocaine medicated plaster for localized neuropathic pain related to disk herniation. However, owing to the small sample size, further investigation in a larger-scale controlled trial is warranted. PMID:22973116

  10. Cervical lung herniation complicating a case of acute asphyxial asthma in a child.

    PubMed

    Martchek, Melissa A; Padilla, Benjamin E; Zonfrillo, Mark R; Friedlaender, Eron Y

    2015-04-01

    The abrupt onset of respiratory failure secondary to asthma, known as acute asphyxial asthma (AAA) in adults, is uncommonly reported in children. Here, we report a case of a child with the acute onset of respiratory failure consistent with AAA complicated by the finding of a neck mass during resuscitation. This 11-year-old boy with a history of asthma initially presented in respiratory failure with altered mental status after the complaint of difficulty in breathing minutes before collapsing at home. Initially, his respiratory failure was thought to be secondary to status asthmaticus, and treatment was initiated accordingly. However, a neck mass noted during the resuscitation was cause for concern, and other etiologies for his respiratory failure were considered, including an airway obstructing neck mass. After pediatric surgery and anesthesia consultation for intubation and possible tracheostomy placement, general anesthesia was induced in the operating room with an inhaled anesthetic, with prompt resolution of the bronchspasm and decompression of the neck mass. Review of the imaging and clinical course ultimately yielded a diagnosis of cervical lung herniation as the etiology of his neck mass. We report this case of AAA and cervical lung herniation and a review of the literature of these 2 uncommon phenomena in children. PMID:25831031

  11. Chondrule transport in protoplanetary discs

    NASA Astrophysics Data System (ADS)

    Goldberg, Aaron Z.; Owen, James E.; Jacquet, Emmanuel

    2015-10-01

    Chondrule formation remains one of the most elusive early Solar system events. Here, we take the novel approach of employing numerical simulations to investigate chondrule origin beyond purely cosmochemical methods. We model the transport of generically produced chondrules and dust in a 1D viscous protoplanetary disc model in order to constrain the chondrule formation events. For a single formation event we are able to match analytical predictions of the memory they retain of each other (complementarity), finding that a large mass accretion rate (?10-7 M? yr-1) allows for delays on the order of the disc's viscous time-scale between chondrule formation and chondrite accretion. Further, we find older discs to be severely diminished of chondrules, with accretion rates ?10-9 M? yr-1 for nominal parameters. We then characterize the distribution of chondrule origins in both space and time, as functions of disc parameters and chondrule formation rates, in runs with continuous chondrule formation and both static and evolving discs. Our data suggest that these can account for the observed diversity between distinct chondrite classes, if some diversity in accretion time is allowed for.

  12. The Vacuum Bubble Nucleation

    SciTech Connect

    Lee, Bum-Hoon; Lee, Wonwoo

    2009-07-10

    We study the nucleation of a vacuum bubble via the vacuum-to-vacuum tunneling transition in curved spacetime. We consider Coleman-de Luccia's semiclassical approximation at zero temperature in pure Einstein theory of gravity and the theory with nonminimal coupling. We discuss the dynamics of a nucleated vacuum bubble.

  13. Brain herniation through an internal subdural membrane: a rare complication seen with chronic subdural hematomas in children. Case report.

    PubMed

    Acakpo-Satchivi, Leslie; Luerssen, Thomas G

    2007-12-01

    The authors report an unusual case of cortical herniation into a chronic subdural hematoma (SDH). The patient was successfully treated with good outcome. A 4-month-old boy with a history of macrocrania and very large bilateral chronic SDHs underwent subduroperitoneal shunt treatment shortly after presentation. Eight months later he developed a new-onset seizure disorder, which was localized by electroencephalography to the right frontal region. Neuroimaging demonstrated the development of a focal herniation of the brain through a subdural membrane into the subdural space. The patient underwent a craniotomy to resect the seizure focus and the herniated cortex. The subdural shunt was subsequently replaced. After 2 years of follow-up, the patient remains free of seizures, is on no medication regimen, and is neurologically and developmentally normal. To the authors' knowledge, this is only the fourth report in the medical literature of cortical herniation through a chronic subdural membrane and the first in which successful treatment with a good outcome is described. PMID:18154018

  14. Gastrocnemius muscle herniation as a rare differential diagnosis of ankle sprain: case report and review of the literature

    PubMed Central

    2012-01-01

    Background Muscle herniation of the leg is a rare clinical entity. Yet, knowing this condition is necessary to avoid misdiagnosis and delayed treatment. In the extremities, muscle herniation most commonly occurs as a result of an acquired fascial defect, often due to trauma. Different treatment options for symptomatic extremity muscle herniation in the extremities, including conservative treatment, fasciotomy and mesh repair have been described. Case presentation We present the case of a patient who presented with prolonged symptoms after an ankle sprain. The clinical picture showed a fascial insufficiency with muscle bulging under tension. Ultrasound and MRI imaging confirmed the diagnosis of muscle hernia of the medial gastrocnemius on the right leg. Conservative treatment did not lead to success. Therefore, the fascial defect was treated surgically by repairing the muscle herniation using a synthetic vicryl propylene patch. Conclusions Muscle hernias should be taken into consideration as a rare differential diagnosis whenever patients present with persisting pain or soft tissue swelling after ankle sprain. Diagnosis is mainly based on clinical aspect and physical examination, but can be confirmed by radiologic imaging techniques, including (dynamic) ultrasound and MRI. If conservative treatment fails, we recommend the closure with mesh patches for large fascial defects. PMID:22417228

  15. Debris disc formation induced by planetary growth

    NASA Astrophysics Data System (ADS)

    Kobayashi, H.; Löhne, T.

    2014-08-01

    Several hundred stars older than 10 million years have been observed to have infrared excesses. These observations are explained by dust grains formed by the collisional fragmentation of hidden planetesimals. Such dusty planetesimal discs are known as debris discs. In a dynamically cold planetesimal disc, collisional coagulation of planetesimals produces planetary embryos which then stir the surrounding leftover planetesimals. Thus, the collisional fragmentation of planetesimals that results from planet formation forms a debris disc. We aim to determine the properties of the underlying planetesimals in debris discs by numerically modelling the coagulation and fragmentation of planetesimal populations. The brightness and temporal evolution of debris discs depend on the radial distribution of planetesimal discs, the location of their inner and outer edges, their total mass, and the size of planetesimals in the disc. We find that a radially narrow planetesimal disc is most likely to result in a debris disc that can explain the trend of observed infrared excesses of debris discsvvv around G-type stars, for which planet formation occurs only before 100 million years. Early debris disc formation is induced by planet formation, while the later evolution is explained by the collisional decay of leftover planetesimals around planets that have already formed. Planetesimal discs with underlying planetesimals of radii ˜100 km at ?30 au most readily explain the Spitzer Space Telescope 24 and 70 ?m fluxes from debris discs around G-type stars.

  16. Black hole accretion disc impacts

    E-print Network

    Pihajoki, Pauli

    2015-01-01

    We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength {\\lambda} = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.

  17. Natural vacuum electronics

    NASA Technical Reports Server (NTRS)

    Leggett, Nickolaus

    1990-01-01

    The ambient natural vacuum of space is proposed as a basis for electron valves. Each valve is an electron controlling structure similiar to a vacuum tube that is operated without a vacuum sustaining envelope. The natural vacuum electron valves discussed offer a viable substitute for solid state devices. The natural vacuum valve is highly resistant to ionizing radiation, system generated electromagnetic pulse, current transients, and direct exposure to space conditions.

  18. Determination and comparison of specifics of nucleus pulposus cells of human intervertebral disc in alginate and chitosan–gelatin scaffolds

    PubMed Central

    Renani, Hamid Bahramian; Ghorbani, Masood; Beni, Batool Hashemibeni; Karimi, Z; Mirhosseini, MM; Zarkesh, H; Kabiri, A

    2012-01-01

    Introduction: Low back pain is a major economical and social problem nowadays. Intervertebral disc herniation and central degeneration of disc are two major reasons of low back pain that occur because of structural impairment of disc. The intervertebral disc contains three parts as follows : Annulus fibrosus, transitional region, and nucleus pulposus, which forms the central nucleus of the disc. The reduction of cell count and extracellular matrix, especially in nucleus pulposus, causes disc degeneration. Different scaffolds (natural and synthetic) have been used for tissue repairing and regeneration of the intervertebral disc in tissue engineering. Most scaffolds have biodegradable and biocompatible characteristics and also prepare a fine condition for proliferation and migration of cells. In this study, proliferation of NP cells of human intervertebral disc compromised in Chitosan-gelatin scaffold with alginate scaffold was studied. Materials and Methods: NP cells derived from nucleus pulposus by collagenase enzymatic hydrolysis. They were derived from patients who undergoing open surgery for discectomy in the Isfahan Alzahra hospital. Chitosan was blended with gelatin and glutaraldehyde was used for cross linking the two polymers. Then, alginate scaffold was prepared. Cellular suspension with 1 × 105 transferred to each scaffold and cultured for 21 days. Cell viability and proliferation investigated by trypan blue and (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Scanning electron microscope (SEM) was used to assert the porosity and to survey structure of scaffold. Results: MTT assay dem1onstrated that cell viability of third day had significant difference in contrast by first day in both scaffolds. Accordingly, there was a significant decreased in cellular viability from day 3 to 21. Results of the cell count showed a punctual elevation cell numbers for alginate scaffold but there was no similar result for chitosan–gelatin scaffold. Conclusion: Alginate scaffold prepared a better condition for proliferation of NP cells in comparison with chitosan–gelatin scaffold. Results of this study suggest that alginate scaffold could be useful in in vivo studies and treatment. PMID:23326811

  19. Physics and chemistry of gas in discs 

    E-print Network

    Tilling, Ian

    2013-11-28

    Protoplanetary discs set the initial conditions for planet formation. By combining observations with detailed modelling, it is possible to constrain the physics and chemistry in such discs. I have used the detailed ...

  20. DISC-UK DataShare 

    E-print Network

    Rice, Robin

    DISC-UK DataShare (http://www.disc-uk.org/datashare.html) is a JISC-funded collaborative project led by EDINA and Edinburgh University Data Library, with the Universities of Oxford and Southampton as partners, and the ...

  1. Computer animation via optical video disc

    E-print Network

    Bender, Walter

    1981-01-01

    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 ...

  2. Expression of DISC1 binding partners is reduced in schizophrenia and associated with DISC1 SNPs

    E-print Network

    Wang, Kuan Hong

    Expression of DISC1 binding partners is reduced in schizophrenia and associated with DISC1 SNPs 1, 2005; Revised December 30, 2005; Accepted February 8, 2006 DISC1 has been identified-terminus-truncated DISC1 disrupts intracellular transport, neural architecture and migration, perhaps because it fails

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

    PubMed

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

    2015-03-01

    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

  4. Optical Disc Applications in Libraries.

    ERIC Educational Resources Information Center

    Andre, Pamela Q. J.

    1989-01-01

    Discusses a variety of library applications of optical disc storage technology, including CD-ROM, digital videodisc, and WORM. Research and development projects at the Library of Congress, National Library of Medicine, and National Agricultural Library are described, products offered by library networks are reviewed, and activities in academic and…

  5. Electromagnetic Levitation of a Disc

    ERIC Educational Resources Information Center

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

    2012-01-01

    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…

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

    NASA Astrophysics Data System (ADS)

    Foucart, Francois; Lai, Dong

    2014-12-01

    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.

  7. Indian Vacuum Society: The Indian Vacuum Society

    NASA Astrophysics Data System (ADS)

    Saha, T. K.

    2008-03-01

    The Indian Vacuum Society (IVS) was established in 1970. It has over 800 members including many from Industry and R & D Institutions spread throughout India. The society has an active chapter at Kolkata. The society was formed with the main aim to promote, encourage and develop the growth of Vacuum Science, Techniques and Applications in India. In order to achieve this aim it has conducted a number of short term courses at graduate and technician levels on vacuum science and technology on topics ranging from low vacuum to ultrahigh vacuum So far it has conducted 39 such courses at different parts of the country and imparted training to more than 1200 persons in the field. Some of these courses were in-plant training courses conducted on the premises of the establishment and designed to take care of the special needs of the establishment. IVS also regularly conducts national and international seminars and symposia on vacuum science and technology with special emphasis on some theme related to applications of vacuum. A large number of delegates from all over India take part in the deliberations of such seminars and symposia and present their work. IVS also arranges technical visits to different industries and research institutes. The society also helped in the UNESCO sponsored post-graduate level courses in vacuum science, technology and applications conducted by Mumbai University. The society has also designed a certificate and diploma course for graduate level students studying vacuum science and technology and has submitted a syllabus to the academic council of the University of Mumbai for their approval, we hope that some colleges affiliated to the university will start this course from the coming academic year. IVS extended its support in standardizing many of the vacuum instruments and played a vital role in helping to set up a Regional Testing Centre along with BARC. As part of the development of vacuum education, the society arranges the participation of expert members on the subject to deliver lectures and take part in devising courses in the universities. IVS publishes a quarterly called the `Bulletin of Indian Vacuum Society' since its inception, in which articles on vacuum and related topics are published. NIRVAT, news, announcements, and reports are the other features of the Bulletin. The articles in the Bulletin are internationally abstracted. The Bulletin is distributed free to all the members of the society. The society also publishes proceedings of national/international symposia and seminars, manuals, lecture notes etc. It has published a `Vacuum Directory' containing very useful information on vacuum technology. IVS has also set up its own website http://www.ivsnet.org in January 2002. The website contains information about IVS, list of members, list of EC members, events and news, abstracts of articles published in the `Bulletin of Indian Vacuum Society', utilities, announcements, reports, membership and other forms which can be completed online and also gives links to other vacuum societies. Our Society has been a member of the executive council of the International Union of Vacuum Science, Techniques and Applications (IUVSTA) and its various committees since 1970. In 1983 IVS conducted an International Symposium on Vacuum Technology and Nuclear Applications in BARC, Mumbai, under the sponsorship of IUVSTA. In 1987 IVS arranged the Triennial International Conference on Thin Films in New Delhi, where more than 200 foreign delegates participated. IVS also hosted the IUVSTA Executive Council Meeting along with the conference. The society organized yet again an International Conference on Vacuum Science and Technology and SRS Vacuum Systems at CAT, Indore in1995. IVS arranges the prestigious Professor Balakrishnan Memorial Lecture in memory of its founder vice-president. Leading scientists from India and abroad in the field are invited to deliver the talks. So far 23 lectures have been held in this series. IVS has instituted the `IVS- Professor D Y Phadke Memorial Prize' in memory of our founder presid

  8. Amniotic Sac Herniation Through a Prior Cornual Scar in The Third Trimester

    PubMed Central

    Saad, Antonio F.; Costantine, Maged M.; Saade, George; Makhlouf, Michel

    2015-01-01

    Introduction?Uterine rupture occurs in less than 0.1% of pregnancies. This complication can be detrimental to mother and fetus if not detected and managed in a timely manner. We report an unusual presentation of uterine scar rupture that was diagnosed on ultrasound in a completely stable patient with reassuring fetal status. Case Report?A 24-year-old Gravida 5, Para 3 with history of cornual resection for ectopic pregnancy and two previous uterine ruptures presented at 30 weeks' gestation with worsening abdominal pain. Ultrasound identified herniation of the amniotic sac with fetal parts. The patient underwent cesarean delivery and cornual defect repair. Conclusion?Close observation and early delivery remain vital to the patient's management. PMID:26495171

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

    A previous study [1] reported the instantaneous risk of developing a Herniated Nucleus Pulosus (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 Boards assessment of back pain, assess the risk of injury due to dynamic loads, and update the dataset analyzed which contained data through December 31, 2006.

  10. Mechanical response of the herniated human abdomen to the placement of different prostheses.

    PubMed

    Hernández-Gascón, Belén; Peña, Estefanía; Grasa, Jorge; Pascual, Gemma; Bellón, Juan M; Calvo, Begoña

    2013-05-01

    This paper describes a method designed to model the repaired herniated human abdomen just after surgery and examine its static mechanical response to the maximum intra-abdominal pressure provoked by a physiological movement (standing cough). The model is based on the real geometry of the human abdomen bearing a large incisional hernia with several anatomical structures differentiated by MRI. To analyze the outcome of hernia repair, the surgical procedure was simulated by modeling a prosthesis placed over the hernia. Three surgical meshes with different mechanical properties were considered: an isotropic heavy-weight mesh (Surgipro®), a slightly anisotropic light-weight mesh (Optilene®), and a highly anisotropic medium-weight mesh (Infinit®). Our findings confirm that anisotropic implants need to be positioned such that the most compliant axis of the mesh coincides with the craneo-caudal direction of the body. PMID:24231960

  11. Lumbar Disk Herniation in the Spine Patient Outcomes Research Trial (SPORT): Does Educational Attainment Impact Outcome?

    PubMed Central

    Olson, Patrick R.; Lurie, Jon D.; Frymoyer, John; Walsh, Thomas; Zhao, Wenyan; Abdu, William A.; Weinstein, James N.

    2011-01-01

    Study Design Randomized trial with concurrent observational cohort. 1171 patients were divided into subgroups by educational attainment: high school or less, some college, and college degree or above. Objective To assess the influence of education level on outcomes for treatment of lumbar disk herniation. Summary of Background Data Educational attainment has been demonstrated to have an inverse relationship with pain perception, co-morbidities, and mortality. Methods The Spine Patient Outcomes Research Trial enrolled surgical candidates (imaging-confirmed disk herniation with at least 6 weeks of persistent signs and symptoms of radiculopathy) from 13 multidisciplinary spine clinics in 11 US states. Treatments were standard open diskectomy vs. non-operative treatment. Outcomes were changes from baseline for SF-36 bodily pain (BP) and physical function (PF) scales and the modified Oswestry Disability Index (ODI) at 6 weeks, 3 months, 6 months, and yearly through 4 years. Results Substantial improvement was seen in all patient cohorts. Surgical outcomes did not differ by level of education. For non-operative outcomes, however, higher levels of education were associated with significantly greater overall improvement over 4 years in BP (p=0.007), PF (p=0.001) and ODI (p=0.003). At 4 years a “dose-response” type relationship was shown for BP (high school or less 25.5; some college 31; college graduate or above 36.3; p= 0.004); results were similar for PF and ODI. The success of non-operative treatment in the more educated cohort resulted in an attenuation of the relative benefit of surgery. Conclusions Patients with higher educational attainment demonstrated significantly greater improvement with non-operative treatment while educational attainment was not associated with surgical outcomes. PMID:21311402

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

    PubMed Central

    2013-01-01

    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

  13. 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

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

    2015-04-01

    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. PMID:24227682

  14. Cosmology of Vacuum

    E-print Network

    V. Burdyuzha; G. Vereshkov

    2007-12-29

    Shortly the vacuum component of the Universe from the geometry point of view and from the point of view of the standard model of physics of elementary particles is discussed. Some arguments are given to the calculated value of the cosmological constant (Zeldovich approximation). A new component of space vacuum (the gravitational vacuum condensate) is involved the production of which has fixed time in our Universe. Also the phenomenon of vacuum selforganization must be included in physical consideration of the Universe evolution.

  15. Radiation hard vacuum switch

    DOEpatents

    Boettcher, Gordon E. (Albuquerque, NM)

    1990-01-01

    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.

  16. Factors regulating viable cell density in the intervertebral disc: blood supply in relation to disc height

    PubMed Central

    Boubriak, Olga A; Watson, Natasha; Sivan, Sarit S; Stubbens, Naomi; Urban, Jill P G

    2013-01-01

    The intervertebral disc is an avascular tissue, maintained by a small population of cells that obtain nutrients mainly by diffusion from capillaries at the disc–vertebral body interface. Loss of this nutrient supply is thought to lead to disc degeneration, but how nutrient supply influences viable cell density is unclear. We investigated two factors that influence nutrient delivery to disc cells and hence cell viability: disc height and blood supply. We used bovine caudal discs as our model as these show a gradation in disc height. We found that although disc height varied twofold from the largest to the smallest disc studied, it had no significant effect on cell density, unlike the situation found in articular cartilage. The density of blood vessels supplying the discs was markedly greater for the largest disc than the smallest disc, as was the density of pores allowing capillary penetration through the bony endplate. Results indicate that changes in blood vessels in the vertebral bodies supplying the disc, as well as changes in endplate architecture appear to influence density of cells in intervertebral discs. PMID:23311982

  17. The Classical Vacuum.

    ERIC Educational Resources Information Center

    Boyer, Timothy H.

    1985-01-01

    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…

  18. Grain charging in protoplanetary discs

    E-print Network

    Ilgner, Martin

    2011-01-01

    Recent work identified a growth barrier for dust coagulation that originates in the electric repulsion between colliding particles. Depending on its charge state, dust material may have the potential to control key processes towards planet formation such as MHD (magnetohydrodynamic) turbulence and grain growth which are coupled in a two-way process. We quantify the grain charging at different stages of disc evolution and differentiate between two very extreme cases: compact spherical grains and aggregates with fractal dimension D_f = 2. Applying a simple chemical network that accounts for collisional charging of grains, we provide a semi-analytical solution. This allowed us to calculate the equilibrium population of grain charges and the ionisation fraction efficiently. The grain charging was evaluated for different dynamical environments ranging from static to non-stationary disc configurations. The results show that the adsorption/desorption of neutral gas-phase heavy metals, such as magnesium, effects the ...

  19. Laminated composite disc flywheel development

    NASA Astrophysics Data System (ADS)

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

    1980-02-01

    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.

  20. Ptolemy relations for punctured discs

    E-print Network

    Baur, Karin

    2007-01-01

    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.

  1. Proto-planetary disc evolution and dispersal

    NASA Astrophysics Data System (ADS)

    Rosotti, Giovanni Pietro

    2015-05-01

    Planets form from gas and dust discs in orbit around young stars. The timescale for planet formation is constrained by the lifetime of these discs. The properties of the formed planetary systems depend thus on the evolution and final dispersal of the discs, which is the main topic of this thesis. Observations reveal the existence of a class of discs called "transitional", which lack dust in their inner regions. They are thought to be the last stage before the complete disc dispersal, and hence they may provide the key to understanding the mechanisms behind disc evolution. X-ray photoevaporation and planet formation have been studied as possible physical mechanisms responsible for the final dispersal of discs. However up to now, these two phenomena have been studied separately, neglecting any possible feedback or interaction. In this thesis we have investigated what is the interplay between these two processes. We show that the presence of a giant planet in a photo-evaporating disc can significantly shorten its lifetime, by cutting the inner regions from the mass reservoir in the exterior of the disc. This mechanism produces transition discs that for a given mass accretion rate have larger holes than in models considering only X-ray photo-evaporation, constituting a possible route to the formation of accreting transition discs with large holes. These discs are found in observations and still constitute a puzzle for the theory. Inclusion of the phenomenon called "thermal sweeping", a violent instability that can destroy a whole disc in as little as 10 4 years, shows that the outer disc left can be very short-lived (depending on the X-ray luminosity of the star), possibly explaining why very few non accreting transition discs are observed. However the mechanism does not seem to be efficient enough to reconcile with observations. In this thesis we also show that X-ray photo-evaporation naturally explains the observed correlation between stellar masses and accretion rates and is therefore the ideal candidate for driving disc evolution. Another process that can influence discs is a close encounter with another star. In this thesis we develop a model to study the effect of stellar dynamics in the natal stellar cluster on the discs, following for the first time at the same time the stellar dynamics together with the evolution of the discs. We find that, although close encounters with stars are unlikely to change significantly the mass of a disc, they can change substantially its size, hence imposing an upper limit on the observed disc radii. Finally, we investigated in this thesis whether discs can be reformed after their dispersal. If a star happens to be in a region that is currently forming stars, it can accrete material from the interstellar medium. This mechanism may result in the production of "second generation" discs such that in a given star forming region a few percent of stars may still possess a disc, in tentative agreement with observations of so called "old accretors", which are difficult to explain within the current paradigm of disc evolution and dispersal.

  2. Magnetorotational instability in protoplanetary discs

    NASA Astrophysics Data System (ADS)

    Salmeron, Raquel; Wardle, Mark

    2005-07-01

    We investigate the linear growth and vertical structure of the magnetorotational instability (MRI) in weakly ionized, stratified accretion discs. The magnetic field is initially vertical and dust grains are assumed to have settled towards the mid-plane, so charges are carried by electrons and ions only. Solutions are obtained at representative radial locations from the central protostar for different choices of the initial magnetic field strength, sources of ionization, disc structure and configuration of the conductivity tensor. The MRI is active over a wide range of magnetic field strengths and fluid conditions in low-conductivity discs. Moreover, no evidence was found of a low-limit field strength below which unstable modes do not exist. For the minimum-mass solar nebula model, incorporating cosmic ray ionization, perturbations grow at 1 au for B<~ 8 G. For a significant subset of these strengths (200mG <~B<~ 5G), the maximum growth rate is of the order of the ideal magnetohydrodynamic (MHD) rate (0.75?). Hall conductivity modifies the structure and growth rate of global unstable modes at 1 au for all magnetic field strengths that support MRI. As a result, at this radius, modes obtained with a full conductivity tensor grow faster and are active over a more extended cross-section of the disc than perturbations in the ambipolar diffusion limit. For relatively strong fields (e.g. B>~ 200 mG), ambipolar diffusion alters the envelope shapes of the unstable modes, which peak at an intermediate height, instead of being mostly flat as modes in the Hall limit are in this region of parameter space. Similarly, when cosmic rays are assumed to be excluded from the disc by the winds emitted by the magnetically active protostar, unstable modes grow at this radius for B<~ 2 G. For strong fields, perturbations exhibit a kink at the height where X-ray ionization becomes active. Finally, for R= 5 au (10 au), unstable modes exist for B<~ 800 mG (B<~ 250 mG) and the maximum growth rate is close to the ideal-MHD rate for 20 <~B<~ 500 mG (2 <~B<~ 50 mG). Similarly, perturbations incorporating Hall conductivity have a higher wavenumber and grow faster than solutions in the ambipolar diffusion limit for B<~ 100 mG (B<~ 10 mG). Unstable modes grow even at the mid-plane for B>~ 100 mG (B~ 1 mG), but for weaker fields, a small dead region exists. This study shows that, despite the low magnetic coupling, the magnetic field is dynamically important for a large range of fluid conditions and field strengths in protostellar discs. An example of such magnetic activity is the generation of MRI unstable modes, which are supported at 1 au for field strengths up to a few gauss. Hall diffusion largely determines the structure and growth rate of these perturbations for all studied radii. At radii of order 1 au, in particular, it is crucial to incorporate the full conductivity tensor in the analysis of this instability and more generally in studies of the dynamics of astrophysical discs.

  3. Debris discs in binaries: a numerical study

    E-print Network

    Thebault, Philippe; Augereau, Jean-Charles

    2010-01-01

    Debris disc analysis and modelling provide crucial information about the structure and the processes at play in extrasolar planetary systems. In binary systems, this issue is more complex because the disc should in addition respond to the companion star's perturbations. We explore the dynamical evolution of a collisionally active debris disc for different initial parent body populations, diverse binary configurations and optical depths. We focus on the radial extent and size distribution of the disc at a stationary state. We numerically follow the evolution of $10^{5}$ massless small grains, initially produced from a circumprimary disc of parent bodies following a size distribution in $dN \\propto s^{-3.5}$ds . Grains are submitted to both stars' gravity as well as radiation pressure. In addition, particles are assigned an empirically derived collisional lifetime. For all the binary configurations the disc extends far beyond the critical semimajor axis $a_crit$ for orbital stability. This is due to the steady ...

  4. On the theory of disc photoevaporation

    E-print Network

    Owen, James E; Ercolano, Barbara

    2011-01-01

    We discuss a hydrodynamical model for the dispersal of protoplanetary discs around young, low mass (100) luminosity ratios, the FUV constricts the X-ray flow and may dominate the mass-loss. Simulations of low mass discs with inner holes demonstrate a further stage of disc clearing, which we call `thermal sweeping'. This process occurs when the mid-plane pressure drops to sufficiently low values. At this stage a bound, warm, X-ray heated region becomes sufficiently large and unstable, such that the remaining disc material is cleared on approximately dynamical time-scales. This process significantly reduces the time taken to clear the outer regions of the disc, resulting in an expected transition disc population that will be dominated by accreting objects, as indicated by recent observations.

  5. HD 98800: A most unusual debris disc

    E-print Network

    P. E. Verrier; N. W. Evans

    2008-07-31

    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.

  6. On the evolution of the protolunar disc

    PubMed Central

    Ward, William R.

    2014-01-01

    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

  7. Accretion Discs Show Their True Colours

    NASA Astrophysics Data System (ADS)

    2008-07-01

    Quasars are the brilliant cores of remote galaxies, at the hearts of which lie supermassive black holes that can generate enough power to outshine the Sun a trillion times. These mighty power sources are fuelled by interstellar gas, thought to be sucked into the hole from a surrounding 'accretion disc'. A paper in this week's issue of the journal Nature, partly based on observations collected with ESO's Very Large Telescope, verifies a long-standing prediction about the intensely luminous radiation emitted by these accretion discs. Uncovering the disc ESO PR Photo 21/08 Uncovering the inner disc "Astronomers were puzzled by the fact that the best models of these discs couldn't quite be reconciled with some of the observations, in particular, with the fact that these discs did not appear as blue as they should be," explains lead-author Makoto Kishimoto. Such a discrepancy could be the signal that there was something very wrong with the models. With his colleagues, he investigated this discrepancy by studying the polarised light from six quasars. This enabled them to demonstrate that the disc spectrum is as blue as predicted. "The crucial observational difficulty here has been that the disc is surrounded by a much larger torus containing hot dust, whose light partly outshines that of the disc," says Kishimoto. "Because the light coming from the disc is scattered in the disc vicinity and thus polarised, by observing only polarised light from the quasars, one can uncover the buried light from the disc." In a similar way that a fisherman would wear polarised sunglasses to help get rid of the glare from the water surface and allow him to see more clearly under the water, the filter on the telescope allowed the astronomers to see beyond surrounding clouds of dust and gas to the blue colour of the disc in infrared light. The observations were done with the FORS and ISAAC instruments on one of the 8.2-m Unit Telescopes of ESO's Very Large Telescope, located in the Atacama Desert, in Chile, as well as several other telescopes, including STFC's UKIRT. The standard picture of the accretion disc is therefore vindicated. The authors believe that further measurements could eventually provide valuable insight into how and where the disc ends, and how material is being supplied to the disc.

  8. Vacuum pump aids ejectors

    SciTech Connect

    Nelson, R.E.

    1982-12-01

    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.

  9. Total Disc Replacement in Lumbar Degenerative Disc Diseases

    PubMed Central

    2015-01-01

    More than 10 years have passed since lumbar total disc replacement (LTDR) was introduced for the first time to the world market for the surgical management of lumbar degenerative disc disease (DDD). It seems like the right time to sum up the relevant results in order to understand where LTDR stands on now, and is heading forward to. The pathogenesis of DDD has been currently settled, but diagnosis and managements are still controversial. Fusion is recognized as golden standard of surgical managements but has various kinds of shortcomings. Lately, LTDR has been expected to replace fusion surgery. A great deal of LTDR reports has come out. Among them, more than 5-year follow-up prospective randomized controlled studies including USA IDE trials were expected to elucidate whether for LTDR to have therapeutic benefit compared to fusion. The results of these studies revealed that LTDR was not inferior to fusion. Most of clinical studies dealing with LTDR revealed that there was no strong evidence for preventive effect of LTDR against symptomatic degenerative changes of adjacent segment disease. LTDR does not have shortcomings associated with fusion. However, it has a potentiality of the new complications to occur, which surgeons have never experienced in fusion surgeries. Consequently, longer follow-up should be necessary as yet to confirm the maintenance of improved surgical outcome and to observe any very late complications. LTDR still may get a chance to establish itself as a substitute of fusion both nominally and virtually if it eases the concerns listed above. PMID:26713139

  10. Physical Vacuum in Superconductors

    E-print Network

    Clovis Jacinto de Matos

    2009-08-31

    Although experiments carried out by Jain et al. showed that the Cooper pairs obey the strong equivalence principle, The measurement of the Cooper pairs inertial mass by Tate et al. revealed an anomalous excess of mass. In the present paper we interpret these experimental results in the framework of an electromagnetic model of dark energy for the superconductors' vacuum. We argue that this physical vacuum is associated with a preferred frame. Ultimately from the conservation of energy for Cooper pairs we derive a model for a variable vacuum speed of light in the superconductors physical vacuum in relation with a possible breaking of the weak equivalence principle for Cooper pairs.

  11. Vacuum probe surface sampler

    NASA Technical Reports Server (NTRS)

    Zahlava, B. A. (inventor)

    1973-01-01

    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.

  12. 21 CFR 872.3970 - Interarticular disc prosthesis (interpositional implant).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Interarticular disc prosthesis (interpositional implant). 872.3970 Section 872.3970...Interarticular disc prosthesis (interpositional implant). (a) Identification. An interarticular disc prosthesis (interpositional implant) is a device that is intended to...

  13. Use NASA GES DISC Data in ArcGIS

    NASA Technical Reports Server (NTRS)

    Yang, Wenli; Pham, Long B.; Kempler, Steve

    2015-01-01

    This presentation describes GIS relevant data at NASA Goddard Earth Sciences Data and Information Services Center (GES DISC), GES DISC Services and Support for GIS Users, and use cases of GES DISC data in ArcGIS.

  14. Brain herniation induced by drainage of subdural hematoma in spontaneous intracranial hypotension

    PubMed Central

    Chotai, Silky; Kim, Jong-Hyun; Kim, Joo-Han; Kwon, Taek-Hyun

    2013-01-01

    Spontaneous intracranial hypotension (SIH), typically presents with orthostatic headache, low pressure on lumbar tapping, and diffuse pachymeningeal enhancement on magnetic resonance imaging. SIH is often accompanied by subdural fluid collections, which in most cases responds to conservative treatment or spinal epidural blood patch. Several authors advocate that large subdural hematoma with acute deterioration merits surgical drainage; however, few have reported complications following craniotomy. We describe a complicated case of SIH, which was initially diagnosed as acute subarachnoid hemorrhage with bilateral chronic subdural hematoma (SDH), due to unusual presentation. Burr hole drainage of subdural hematoma was performed due to progressive decrease of consciousness, which then resulted in a huge postoperative epidural hematoma collection. Prompt hematoma evacuation did not restore the patient's consciousness but aggravated downward brain herniation. Trendelenburg position and spinal epidural blood patch achieved a rapid improvement in patient's consciousness. This case indicates that the surgical drainage for chronic SDH in SIH can lead to serious complications and it should be cautiously considered. PMID:24049555

  15. Mechanical behaviour of synthetic surgical meshes: finite element simulation of the herniated abdominal wall.

    PubMed

    Hernández-Gascón, B; Peña, E; Melero, H; Pascual, G; Doblaré, M; Ginebra, M P; Bellón, J M; Calvo, B

    2011-11-01

    The material properties of meshes used in hernia surgery contribute to the overall mechanical behaviour of the repaired abdominal wall. The mechanical response of a surgical mesh has to be defined since the haphazard orientation of an anisotropic mesh can lead to inconsistent surgical outcomes. This study was designed to characterize the mechanical behaviour of three surgical meshes (Surgipro®, Optilene® and Infinit®) and to describe a mechanical constitutive law that accurately reproduces the experimental results. Finally, through finite element simulation, the behaviour of the abdominal wall was modelled before and after surgical mesh implant. Uniaxial loading of mesh samples in two perpendicular directions revealed the isotropic response of Surgipro® and the anisotropic behaviour of Optilene® and Infinit®. A phenomenological constitutive law was used to reproduce the measured experimental curves. To analyze the mechanical effect of the meshes once implanted in the abdomen, finite element simulation of the healthy and partially herniated repaired rabbit abdominal wall served to reproduce wall behaviour before and after mesh implant. In all cases, maximal displacements were lower and maximal principal stresses higher in the implanted abdomen than the intact wall model. Despite the fact that no mesh showed a behaviour that perfectly matched that of abdominal muscle, the Infinit® mesh was able to best comply with the biomechanics of the abdominal wall. PMID:21763794

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

    NASA Astrophysics Data System (ADS)

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

    2007-05-01

    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.

  17. Photon acceleration in vacuum

    E-print Network

    J. T. Mendonca; M. Marklund; P. K. Shukla; G. Brodin

    2006-08-16

    A new process associated with the nonlinear optical properties of the electromagnetic vacuum, as predicted by quantum electrodynamics, is described. This can be called photon acceleration in vacuum, and corresponds to the frequency shift that takes place when a given test photon interacts with an intense beam of background radiation.

  18. Working in a Vacuum

    ERIC Educational Resources Information Center

    Rathey, Allen

    2005-01-01

    In this article, the author discusses several myths about vacuum cleaners and offers tips on evaluating and purchasing this essential maintenance tool. These myths are: (1) Amps mean performance; (2) Everyone needs high-efficiency particulate air (HEPA): (3) Picking up a "bowling ball" shows cleaning power; (4) All vacuum bags are the same; (5)…

  19. Vacuum Energy Decay

    E-print Network

    Enrique Álvarez; Roberto Vidal

    2011-11-09

    The problem of the vacuum energy decay is studied through the analysis of the vacuum survival amplitude ${\\mathcal A}(z, z')$. Transition amplitudes are computed for finite time-span, $Z\\equiv z^\\prime-z$, and their {\\em late time} behavior is discussed up to first order in the coupling constant, $\\l$.

  20. Vacuuming radioactive sludge

    SciTech Connect

    2006-10-16

    Vacuuming an estimated 55 cubic yards of radioactive sludge from the floor of Hanford's K East Basin was a complicated process. Workers stood on grates suspended above the 20-foot deep basin and manipulated vacuuming equipment at the end of long poles--using underwater cameras to guide their work.

  1. Microfabricated triggered vacuum switch

    DOEpatents

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

    2010-05-11

    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.

  2. Cryogenic vacuum tight adhesive

    NASA Astrophysics Data System (ADS)

    Anashkin, O. P.; Keilin, V. E.; Patrikeev, V. M.

    1999-12-01

    A synthetic adhesive for vacuum tight joints at cryogenic temperatures has been developed. It consists of three components, the main component being epoxy silicone organic resin. The joints made with the adhesive remain vacuum tight at liquid helium temperature, including superfluid helium. It was found possible to connect different materials with the adhesive (copper and stainless steel with each other, aluminum, aluminum alloys, fiberglass, etc.). The joints withstood thermal shock tests of ten repeated sharps cooling to liquid nitrogen temperature and heating in hot water. Using the adhesive a lot of different vacuum tight low temperature joints have been made. More than fifteen years of wide application of this adhesive in vacuum tight cryogenic joints proved its high reliability. Some designs of vacuum tight cryogenic joints are presented and the technique of their manufacturing is described.

  3. Vacuum tunneling in gravity

    NASA Astrophysics Data System (ADS)

    Cho, Y. M.; Pak, D. G.

    2011-08-01

    Topologically non-trivial vacuum structures in gravity models with Cartan variables (vielbein and contortion) are considered. We study the possibility of vacuum spacetime tunneling in Einstein gravity assuming that the vielbein may play a fundamental role in quantum gravitational phenomena. It has been shown that in the case of RP3 space topology, the tunneling between non-trivial topological vacuums can be realized by means of Eguchi-Hanson gravitational instanton. In the Riemann-Cartan geometric approach to quantum gravity, the vacuum tunneling can be provided by means of contortion quantum fluctuations. We define a double self-duality condition for the contortion and give explicit self-dual configurations which can contribute to vacuum tunneling amplitude.

  4. Generation of highly inclined protoplanetary discs through single stellar flybys

    E-print Network

    Xiang-Gruess, Meng

    2015-01-01

    We study the three-dimensional evolution of a viscous protoplanetary disc which is perturbed by a passing star on a parabolic orbit. The aim is to test whether a single stellar flyby is capable to excite significant disc inclinations which would favour the formation of so-called misaligned planets. We use smoothed particle hydrodynamics to study inclination, disc mass and angular momentum changes of the disc for passing stars with different masses. We explore different orbital configurations for the perturber's orbit to find the parameter spaces which allow significant disc inclination generation. Prograde inclined parabolic orbits are most destructive leading to significant disc mass and angular momentum loss. In the remaining disc, the final disc inclination is only below $20^\\circ$. This is due to the removal of disc particles which have experienced the strongest perturbing effects. Retrograde inclined parabolic orbits are less destructive and can generate disc inclinations up to $60^\\circ$. The final disc...

  5. Housing protects laser in vacuum

    NASA Technical Reports Server (NTRS)

    Canali, V. G.

    1978-01-01

    Airtight housing encloses laser for easy alinement and operation in high-vacuum chamber. Beam is transmitted through window into vacuum chamber. Flexible line runs through vacuum chamber to outside, maintaining laser enclosure at atmospheric pressure.

  6. The properties of discs around planets and brown dwarfs as evidence for disc fragmentation

    E-print Network

    Stamatellos, Dimitris

    2015-01-01

    Direct imaging searches have revealed many very low-mass objects, including a small number of planetary mass objects, as wide-orbit companions to young stars. The formation mechanism of these objects remains uncertain. In this paper we present the predictions of the disc fragmentation model regarding the properties of the discs around such low-mass objects. We find that the discs around objects that have formed by fragmentation in discs hosted by Sun-like stars (referred to as 'parent' discs and 'parent' stars) are more massive than expected from the ${M}_{\\rm disc}-M_*$ relation (which is derived for stars with masses $M_*>0.2 {\\rm M}_{\\odot}$). Accordingly, the accretion rates onto these objects are also higher than expected from the $\\dot{M}_*-M_*$ relation. Moreover there is no significant correlation between the mass of the brown dwarf or planet with the mass of its disc nor with the accretion rate from the disc onto it. The discs around objects that form by disc fragmentation have larger than expected m...

  7. The quantum vacuum

    E-print Network

    G. S. Paraoanu

    2014-12-12

    The vacuum is the lowest energy state of a field in a certain region of space. This definition implies that no particles can be present in the vacuum state. In classical physics, the only features of vacuum are those of its geometry. For example, in the general theory of relativity the geometry is a dynamical structure that guides the motion of matter, and, in turn, it is bent and curved by the presence of matter. Other than this, the classical vacuum is a structure void of any physical properties, since classically properties are strictly associated with physical objects such as particles and finite-amplitude fields. The situation is very different in quantum physics. As I will show in this paper, the difference stems from the fact that in quantum physics the properties are not strictly tied to objects. We know for example that physical properties come into existence - as values of observables - only when the object is measured. Thus, quantum physics allows us to detach properties from objects. This has consequences: one does not need pre-existing real objects to create actual properties, and indeed under certain perturbations the quantum vacuum produces observable effects such as energy shifts and creation of particles. An open question is if by necessity the vacuum comes with an embedded geometry, and if it is possible to construct viable physical theories in which geometry is detached from the vacuum.

  8. Spinal cord herniation after multilevel anterior cervical corpectomy and fusion for ossification of the posterior longitudinal ligament of the cervical spine.

    PubMed

    Min, Jun-Hong; Jung, Byung-Joo; Jang, Jee-Soo; Kim, Seok-Kang; Jung, Dae-Jin; Lee, Sang-Ho

    2009-03-01

    The authors report the case of a 52-year-old man who had undergone resection of an ossified posterior longitudinal ligament via the anterior approach. The patient experienced postoperative neurological deterioration that may have been caused by a massive cord herniation associated with a dural defect at the corpectomy site. Spinal cord herniation may develop as a complication of anterior cervical decompression. Surgeons should be alert to this condition when planning to treat cervical ossification of the ossified posterior longitudinal ligament via the anterior approach. PMID:19320584

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

    PubMed Central

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

    2012-01-01

    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

  10. Does Opioid Pain Medication Use Affect the Outcome of Patients with Lumbar Disk Herniation?

    PubMed Central

    Radcliff, Kris; Freedman, Mitchell; Hilibrand, Alan; Isaac, Roman; Lurie, Jon D.; Zhao, Wenyan; Vaccaro, Alex; Albert, Todd; Weinstein, James

    2013-01-01

    Study Design Subgroup analysis of prospective, randomized cohort Objective To review the results of patients who received opioid pain medications during treatment compared to patients who did not receive opioid medications. Summary of Background Data The SPORT trial is a prospective, multicenter study of surgical treatment versus nonoperative treatment for lumbar intervertebral disk herniation (IDH). Methods The study population includes patients enrolled in SPORT for treatment of IDH in combined randomized and observational cohorts. Patients who received opioid medications at baseline (Opioid) were compared to those who did not. (No-Opioid) Results There were 520 patients in the Non-Opioid group and 542 patients in the Opioid group. Among the opioid medication group there were significantly (p<0.001) worse baseline scores in primary and secondary outcome measures. There was an increased percentage of patients in the opioid medication group with the perception of worsening symptoms and neurological deficit (p<0.001). A higher percentage of the opioid patients received surgery (p<0.001) At four years follow-up, there were no significant differences in primary or secondary outcome measures or treatment effect of surgery between opioid and non-opioid medication patients. Opioid medications were associated with increased crossover to surgical treatment (p=0.005) and decreased surgical avoidance. (p=0.01)The incidence of opioid use at four years was 16% among patients who were using opioids at baseline and 5% among patients who were not using opioids at baseline. Conclusion Patients who were treated with opioids had significantly worse baseline pain and quality of life. At final follow-up, there was no long term difference in outcome associated with opioid pain medication use. Opioid medications were not associated with surgical avoidance. The majority of patients who use opioids during the study did not continue usage at four years. PMID:23591657

  11. Evading death by vacuum

    E-print Network

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

    2013-03-15

    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.

  12. Thermophoretic vacuum wand

    DOEpatents

    Klebanoff, Leonard Elliott (San Ramon, CA); Rader, Daniel John (Lafayette, CA)

    2001-01-01

    A thermophoretic vacuum wand that is particularly suited for transporting articles in a cleanroom environment so that potential particle contaminants in the air do not become adhered to the surface of the article is described. The wand includes a housing having a platen with a front surface with suction port(s) through the platen; a vacuum source for applying a negative pressure to the suction port(s); and heating device for the object. Heating the article when it is held by the vacuum wand affords thermophoretic protection that effectively prevents particles in the air from depositing onto the article.

  13. Thermophoretic vacuum wand

    DOEpatents

    Klebanoff, Leonard Elliott (San Ramon, CA); Rader, Daniel John (Lafayette, CA)

    2000-01-01

    A thermophoretic vacuum wand that is particularly suited for transporting articles in a cleanroom environment so that potential particle contaminants in the air do not become adhered to the surface of the article is described. The wand includes a housing having a platen with a front surface with suction port(s) through the platen; a vacuum source for applying a negative pressure to the suction port(s); and heating device for the object. Heating the article when it is held by the vacuum wand affords thermophoretic protection that effectively prevents particles in the air from depositing onto the article.

  14. Vacuum-driven Metamorphosis

    E-print Network

    Parker, L; Parker, Leonard; Raval, Alpan

    1999-01-01

    We show that nonperturbative vacuum effects can produce a vacuum-driven transition from a matter-dominated universe to one in which the effective equation of state is that of radiation plus cosmological constant. The actual material content of the universe after the transition remains that of non-relativistic matter. This metamorphosis of the equation of state can be traced to nonperturbative vacuum effects that cause the scalar curvature to remain nearly constant at a well-defined value after the transition, and is responsible for the observed acceleration of the recent expansion of the universe.

  15. Vacuum-driven Metamorphosis

    E-print Network

    Leonard Parker; Alpan Raval

    1999-08-26

    We show that nonperturbative vacuum effects can produce a vacuum-driven transition from a matter-dominated universe to one in which the effective equation of state is that of radiation plus cosmological constant. The actual material content of the universe after the transition remains that of non-relativistic matter. This metamorphosis of the equation of state can be traced to nonperturbative vacuum effects that cause the scalar curvature to remain nearly constant at a well-defined value after the transition, and is responsible for the observed acceleration of the recent expansion of the universe.

  16. Vacuum tight window through which a high power laser beam and a high energy particle beam can be transmitted within close proximity to each other

    SciTech Connect

    Kimura, W.D.

    1984-05-22

    An apparatus and method by which a high-power laser beam and a high-energy particle beam may enter or exit a region, typically filled with gas, to or from another region, typically under vacuum. The two beams are spaced about 3-4 mm apart center-to-center at the entry/exit point and no gas is permitted to leak into the vacuum region. A disc of material capable of resisting high radiation fluxes without forming color centers is sealed into a metallic holding block. Prior to sealing of the disc, a hole approximately 0.16 cm is drilled into the disc while the disc is tilted at or above Brewster's angle forming an eliptical hole. A thin film, approximately 6000 A, indium metallization is sputtered in a circular pattern about the hole and around the edges of a beryllium disc. An indium disc is then sandwiched between the disc with the hole and the beryllium disc touching the indium metallization on each piece.

  17. DISC1 genetics, biology and psychiatric illness

    PubMed Central

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

    2012-01-01

    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

  18. Collapse of vacuum bubbles in a vacuum

    SciTech Connect

    Ng, Kin-Wang; Wang, Shang-Yung

    2011-02-15

    We revisit the dynamics of a false vacuum bubble in a background de Sitter spacetime. We find that there exists a large parameter space that allows the bubble to collapse into a black hole or to form a wormhole. This may have interesting implications for the creation of a baby universe in the laboratory, the string landscape where the bubble nucleation takes place among a plenitude of metastable vacua, and the inflationary physics.

  19. 21 CFR 866.1620 - Antimicrobial susceptibility test disc.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...antimicrobic-impregnated paper discs used to measure by a disc-agar diffusion technique or a disc-broth elution technique the in vitro...bacterial pathogens to antimicrobial agents. In the disc-agar diffusion technique, bacterial susceptibility is...

  20. 21 CFR 866.1620 - Antimicrobial susceptibility test disc.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...antimicrobic-impregnated paper discs used to measure by a disc-agar diffusion technique or a disc-broth elution technique the in vitro...bacterial pathogens to antimicrobial agents. In the disc-agar diffusion technique, bacterial susceptibility is...

  1. 21 CFR 866.1620 - Antimicrobial susceptibility test disc.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...antimicrobic-impregnated paper discs used to measure by a disc-agar diffusion technique or a disc-broth elution technique the in vitro...bacterial pathogens to antimicrobial agents. In the disc-agar diffusion technique, bacterial susceptibility is...

  2. 21 CFR 866.1620 - Antimicrobial susceptibility test disc.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...antimicrobic-impregnated paper discs used to measure by a disc-agar diffusion technique or a disc-broth elution technique the in vitro...bacterial pathogens to antimicrobial agents. In the disc-agar diffusion technique, bacterial susceptibility is...

  3. 21 CFR 872.3970 - Interarticular disc prosthesis (interpositional implant).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Interarticular disc prosthesis (interpositional... disc prosthesis (interpositional implant). (a) Identification. An interarticular disc prosthesis... Food and Drug Administration on or before March 30, 1999, for any interarticular disc...

  4. 21 CFR 872.3970 - Interarticular disc prosthesis (interpositional implant).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Interarticular disc prosthesis (interpositional... disc prosthesis (interpositional implant). (a) Identification. An interarticular disc prosthesis... Food and Drug Administration on or before March 30, 1999, for any interarticular disc...

  5. 21 CFR 872.3970 - Interarticular disc prosthesis (interpositional implant).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Interarticular disc prosthesis (interpositional... disc prosthesis (interpositional implant). (a) Identification. An interarticular disc prosthesis... Food and Drug Administration on or before March 30, 1999, for any interarticular disc...

  6. 21 CFR 872.3970 - Interarticular disc prosthesis (interpositional implant).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Interarticular disc prosthesis (interpositional... disc prosthesis (interpositional implant). (a) Identification. An interarticular disc prosthesis... Food and Drug Administration on or before March 30, 1999, for any interarticular disc...

  7. 21 CFR 872.3970 - Interarticular disc prosthesis (interpositional implant).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Interarticular disc prosthesis (interpositional... disc prosthesis (interpositional implant). (a) Identification. An interarticular disc prosthesis... Food and Drug Administration on or before March 30, 1999, for any interarticular disc...

  8. Optical effects related to Keplerian discs orbiting Kehagias-Sfetsos naked singularities

    NASA Astrophysics Data System (ADS)

    Stuchlík, Zden?k; Schee, Jan

    2014-10-01

    We demonstrate possible optical signatures of the Kehagias-Sfetsos (KS) naked singularity spacetimes representing a spherically symmetric vacuum solution of the modified Ho?ava gravity. In such spacetimes, accretion structures significantly different from those present in standard black hole spacetimes occur due to the ‘antigravity’ effect, which causes an internal static sphere surrounded by Keplerian discs. We focus our attention on the optical effects related to the Keplerian accretion discs, constructing the optical appearance of the Keplerian discs, the spectral continuum due to their thermal radiation, and the spectral profiled lines generated in the innermost parts of such discs. The KS naked singularity signature is strongly encoded in the characteristics of predicted optical effects, especially in cases where the spectral continuum and spectral lines are profiled by the strong gravity of the spacetimes due to the vanishing region of the angular velocity gradient influencing the effectiveness of the viscosity mechanism. We can conclude that optical signatures of KS naked singularities can be well distinguished from the signatures of standard black holes.

  9. Quantum vacuum fluctuations

    E-print Network

    Serge Reynaud; Astrid Lambrecht; Cyriaque Genet; Marc-Thierry Jaekel

    2001-06-19

    The existence of irreducible field fluctuations in vacuum is an important prediction of quantum theory. These fluctuations have many observable consequences, like the Casimir effect which is now measured with good accuracy and agreement with theory, provided that the latter accounts for differences between real experiments and the ideal situation considered by Casimir. But the vacuum energy density calculated by adding field mode energies is much larger than the density observed around us through gravitational phenomena. This ``vacuum catastrophe'' is one of the unsolved problems at the interface between quantum theory on one hand, inertial and gravitational phenomena on the other hand. It is however possible to put properly formulated questions in the vicinity of this paradox. These questions are directly connected to observable effects bearing upon the principle of relativity of motion in quantum vacuum.

  10. Welding space vacuum technology

    NASA Technical Reports Server (NTRS)

    Johnson, R. Barry

    1991-01-01

    The objective was to assist the EH 42 Division in putting together a vacuum system that could attain the desired pressure and be large enough to accommodate the gas-metal arc (GMA) welding fixture apparatus. A major accomplishment was the design and fabrication of the controller/annunciator for the 4' by 8' system. It contains many safety features such as thermocouple set point relays that will only allow inlet and exit gas and vacuum valves to be operated at pre-selected system pressures, and a fail safe mode for power interruptions and operator mistakes. It is felt that significant progress was made in this research effort to weld in a vacuum environment. With continued efforts to increase the pump speeds for vacuum chambers and further studies on weld fixtures and gas inlet pressures, the NASA program will be successful.

  11. Vacuum Camera Cooler

    NASA Technical Reports Server (NTRS)

    Laugen, Geoffrey A.

    2011-01-01

    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.

  12. Cosmology of gravitational vacuum

    E-print Network

    V. Burdyuzha; G. Vereshkov; J. Pacheco

    2007-12-29

    Production of gravitational vacuum defects and their contribution to the energy density of our Universe are discussed. These topological microstructures (defects) could be produced in the result of creation of the Universe from "nothing" when a gravitational vacuum condensate has appeared. They must be isotropically distributed over the isotropic expanding Universe. After Universe inflation these microdefects are smoothed, stretched and broken up. A part of them could survive and now they are perceived as the structures of Lambda-term and an unclustered dark matter. It is shown that the parametrization noninvariance of the Wheeler-De Witt equation can be used to describe phenomenologically vacuum topological defects of different dimensions (worm-holes, micromembranes, microstrings and monopoles). The mathematical illustration of these processes may be the spontaneous breaking of the local Lorentz-invariance of the quasi-classical equations of gravity. Probably the gravitational vacuum condensate has fixed time in our Universe. Besides, 3-dimensional topological defects renormalize Lambda-term.

  13. Vacuum Vessel Remote Handling

    E-print Network

    , seismic, etc.) · Preliminary FEA analysis performed - Linear, static stress analysis - Linear, transient · 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

  14. Archival-grade optical disc design and international standards

    NASA Astrophysics Data System (ADS)

    Fujii, Toru; Kojyo, Shinichi; Endo, Akihisa; Kodaira, Takuo; Mori, Fumi; Shimizu, Atsuo

    2015-09-01

    Optical discs currently on the market exhibit large variations in life span among discs, making them unsuitable for certain business applications. To assess and potentially mitigate this problem, we performed accelerated degradation testing under standard ISO conditions, determined the probable disc failure mechanisms, and identified the essential criteria necessary for a stable disc composition. With these criteria as necessary conditions, we analyzed the physical and chemical changes that occur in the disc components, on the basis of which we determined technological measures to reduce these degradation processes. By applying these measures to disc fabrication, we were able to develop highly stable optical discs.

  15. TFTR diagnostic vacuum controller

    SciTech Connect

    Olsen, D.; Persons, R.

    1981-01-01

    The TFTR diagnostic vacuum controller (DVC) provides in conjunction with the Central Instrumentation Control and Data Acquisition System (CICADA), control and monitoring for the pumps, valves and gauges associated with each individual diagnostic vacuum system. There will be approximately 50 systems on TFTR. Two standard versions of the controller (A and B) wil be provided in order to meet the requirements of two diagnostic manifold arrangements. All pump and valve sequencing, as well as protection features, will be implemented by the controller.

  16. Vacuum self-magnetization?

    SciTech Connect

    Perez Rojas, H.; Rodriguez Querts, E.

    2006-06-19

    We study vacuum properties in a strong magnetic field as the zero temperature and zero density limit of quantum statistics. For charged vector bosons (W bosons) the vacuum energy density diverges for B > B{sub c} = m{sub w}{sup 2}/e, leading to vacuum instability. A logarithmic divergence of vacuum magnetization is found for B = Bc, which suggests that if the magnetic field is large enough, it is self-consistently maintained, and this mechanism actually prevents B from reaching the critical value Bc. For virtual neutral vector bosons bearing an anomalous magnetic moment, the instability of the ground state for B > B{sub c}{sup '} = m{sub n}{sup 2}/q also leads to the vacuum energy density divergence for fields B > B{sub c}{sup '} and to the magnetization divergence for B B{sub c}{sup '}. The possibility of virtual electron-positron pairs bosonization in strong magnetic field and the applicability of the neutral bosons model to describe the virtual positronium behavior in a magnetic field are discussed. We conjecture that this could lead to vacuum self-magnetization in QED.

  17. Protoplanetary disc evolution affected by star-disc interactions in young stellar clusters

    E-print Network

    Rosotti, Giovanni P; Ovelar, Maria de Juan; Hubber, David A; Kruijssen, J M Diederik; Ercolano, Barbara; Walch, Stefanie

    2014-01-01

    Most stars form in a clustered environment. Therefore, it is important to assess how this environment influences the evolution of protoplanetary discs around young stars. In turn, this affects their ability to produce planets and ultimately life. We present here for the first time 3D SPH/N-body simulations that include both the hydrodynamical evolution of the discs around their natal stars, as well as the dynamics of the stars themselves. The discs are viscously evolving, accreting mass onto the central star and spreading. We find penetrating encounters to be very destructive for the discs as in previous studies, although the frequency of such encounters is low. We also find, however, that encounter influence the disc radii more strongly than other disc properties such as the disc mass. The disc sizes are set by the competition between viscous spreading and the disruptive effect of encounters. As discs spread, encounters become more and more important. In the regime of rapid spreading encounters simply trunca...

  18. Eclipse Mapping: Astrotomography of Accretion Discs

    E-print Network

    Baptista, Raymundo

    2015-01-01

    The Eclipse Mapping Method is an indirect imaging technique that transforms the shape of the eclipse light curve into a map of the surface brightness distribution of the occulted regions. Three decades of application of this technique to the investigation of the structure, the spectrum and the time evolution of accretion discs around white dwarfs in cataclysmic variables have enriched our understanding of these accretion devices with a wealth of details such as (but not limited to) moving heating/cooling waves during outbursts in dwarf novae, tidally-induced spiral shocks of emitting gas with sub-Keplerian velocities, elliptical precessing discs associated to superhumps, and measurements of the radial run of the disc viscosity through the mapping of the disc flickering sources. This chapter reviews the principles of the method, discusses its performance, limitations, useful error propagation procedures, as well as highlights a selection of applications aimed at showing the possible scientific problems that ha...

  19. Planet formation in self-gravitating discs 

    E-print Network

    Gibbons, Peter George

    2013-11-28

    The work performed here studies particle dynamics in local two-dimensional simulations of self-gravitating accretion discs with a simple cooling law. It is well known that the structure which arises in the gaseous component ...

  20. Evolution of solids in protoplanetary discs

    NASA Astrophysics Data System (ADS)

    Kornet, K.

    2006-10-01

    1d code designed to track the evolution of solids in protoplanetary discs from an early stage, when all solids are in the dust form, to the stage when most solids are in the form of a planetesimal swarm.

  1. Disc valve for sampling erosive process streams

    DOEpatents

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

    1986-01-01

    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.

  2. Particle Acceleration in (by) Accretion Discs

    E-print Network

    J. I. Katz

    1992-05-04

    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 $e^\\pm$.

  3. Investigation of cryogenic rupture disc design

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

    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.

  4. VACUUM SYSTEMS PHYSICS 359E

    E-print Network

    Landstreet, John D.

    VACUUM SYSTEMS PHYSICS 359E September 28, 2004 INTRODUCTION In this laboratory, you will familiarize yourself with the principles of simple vacuum systems and their use. You will measure the pumping.) VACUUM SYSTEMS AND COMPONENTS In one way or another vacuum techniques appear in most fields of modern

  5. Rossby wave instability in 3D discs

    NASA Astrophysics Data System (ADS)

    Meheut, Heloise; Yu, Cong; Lai, Dong

    2012-05-01

    The Rossby wave instability (RWI) is a promising mechanism for producing large-scale vortices in protoplanetary discs. The instability operates around a density bump in the disc, and the resulting vortices may facilitate planetesimal formation and angular momentum transfer in the disc dead zone. Most previous works on the RWI deal with 2D (height-integrated) discs. However, vortices in 3D may have different dynamical behaviours from those in 2D. Recent numerical simulations of the RWI in 3D global discs by Meheut et al. have revealed intriguing vertical structure of the vortices, including appreciable vertical velocities. In this paper we present a linear analysis of the RWI, in 3D global models of isothermal discs. We calculate the growth rates of the Rossby modes (of various azimuthal wave numbers m= 2-6) trapped around the fiducial density bump and carry out 3D numerical simulations to compare with our linear results. We show that the 3D RWI growth rates are only slightly smaller than the 2D growth rates, and the velocity structures seen in the numerical simulations during the linear phase are in agreement with the velocity eigenfunctions obtained in our linear calculations. This numerical benchmark shows that numerical simulations can accurately describe the instability. The angular momentum transfer rate associated with Rossby vortices is also studied.

  6. Turbulent drag reduction through oscillating discs

    E-print Network

    Wise, Daniel J

    2014-01-01

    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...

  7. Optic disc anomalies and frontonasal dysplasia

    PubMed Central

    Hodgkins, P; Lees, M; Lawson, J; Reardon, W; Leitch, J; Thorogood, P; Winter, R; Taylor, D

    1998-01-01

    AIMS—To document the optic disc abnormalities in patients with frontonasal dysplasia in association with basal encephalocele.?METHODS—Names and hospital numbers of patients with midline clefts were obtained from the ophthalmology and genetics database. Six patients were identified who had the following common findings: midline facial cleft with midline cleft lip and palate; hypertelorism; absent corpus callosum; basal (sphenoethmoidal) encephalocele; and pituitary deficiency (five out of six cases). Ophthalmic examination was performed with fundal photography where possible.?RESULTS—Two patients had unilateral and one a bilateral peripapillary staphyloma. Two patients had bilateral optic disc hypoplasia and one appeared to have a peripapillary staphyloma in one eye and a morning glory disc in the other.?CONCLUSION—Optic disc abnormalities were found in all patients with this constellation of clinical findings. This association appears to represent a distinct subgroup within the spectrum of frontonasal dysplasia. The presence of midline facial anomalies and any dysplastic disc should alert the physician as to the presence of an encephalocele.?? Keywords: frontonasal dysplasia; optic disc; encephalocele PMID:9602627

  8. Discovery of the Fomalhaut C debris disc

    NASA Astrophysics Data System (ADS)

    Kennedy, G. M.; Wyatt, M. C.; Kalas, P.; Duchêne, G.; Sibthorpe, B.; Lestrade, J.-F.; Matthews, B. C.; Greaves, J.

    2014-02-01

    Fomalhaut is one of the most interesting and well-studied nearby stars, hosting at least one planet, a spectacular debris ring and two distant low-mass stellar companions (TW PsA and LP 876-10, a.k.a. Fomalhaut B and C). We observed both companions with Herschel, and while no disc was detected around the secondary, TW PsA, we have discovered the second debris disc in the Fomalhaut system, around LP 876-10. This detection is only the second case of two debris discs seen in a multiple system, both of which are relatively wide (?3000 au for HD 223352/40 and 158 kau [0.77 pc] for Fomalhaut/LP 876-10). The disc is cool (24 K) and relatively bright, with a fractional luminosity Ldisc/L? = 1.2 × 10-4, and represents the rare observation of a debris disc around an M dwarf. Further work should attempt to find if the presence of two discs in the Fomalhaut system is coincidental, perhaps simply due to the relatively young system age of 440 Myr, or if the stellar components have dynamically interacted and the system is even more complex than it currently appears.

  9. Stem Cell Approaches to Intervertebral Disc Regeneration: Obstacles from the Disc Microenvironment.

    PubMed

    Wang, Feng; Shi, Rui; Cai, Feng; Wang, Yun-Tao; Wu, Xiao-Tao

    2015-11-01

    Intervertebral disc (IVD) degeneration results in segmental instability and irritates neural compressive symptoms, such as low back pain and motor deficiency. The transplanting of stem cell into degenerative discs has attracted increasing clinical attention, as a new and proven approach to alleviating disc degeneration and to relieving discogenic pains. Aside from supplementation with stem cells, the IVD itself already contains a pool of stem and progenitor cells. Since the resident disc stem cells are incapable of reversing the pathologic changes that occur during aging and disc degeneration, it has been debated as to whether transplanted stem cells are capable of providing an efficient and durable therapeutic effect, even though there have been positive outcomes in both animal models and in clinical trials. This review aims to decipher the interactions between the stem cell and the disc microenvironment. Within their new niches in the IVD, the exogenous stem cell shows metabolic adaptation to the low-glucose supply, hypoxia, and compressive loadings, but demonstrates little tolerance to the disc-like acidity and hypertonicity. Similarly, the survival of endogenous stem cells is threatened as well by the harsh disc microenvironment, which may exhaust the stem cell resources and restrict the self-repair capacity of a degenerating IVD. To eliminate the intrinsic obstacles within the stressful disc niches, stem cells should be delivered with an injectable scaffold that provides both survival and mechanical support. Quick healing or concretion of the injection injuries, which minimizes stem cell leakage and disturbance to disc homeostasis, is of equal importance toward achieving efficient stem cell-based disc regeneration. PMID:26228642

  10. Complications corner: Anterior thoracic disc surgery with dural tear/CSF fistula and low-pressure pleural drain led to severe intracranial hypotension

    PubMed Central

    Oudeman, Eline A.; Tewarie, Rishi D. S. Nandoe; Jöbsis, G. Joost; Arts, Mark P.; Kruyt, Nyika D.

    2015-01-01

    Background: Thoracic disc surgery can lead to a life-threatening complication: intracranial hypotension due to a subarachnoid-pleural fistula. Case Description: We report a 63-year-old male with paraparesis due to multiple herniated thoracic discs, with compressive myelopathy. The patient required a circumferential procedure including a laminectomy/fusion followed by an anterior thoracic decompression to address both diffuse idiopathic skeletal hyperostosis (DISH) anteriorly and posterior stenosis. The postoperative course was complicated by severe intracranial hypotension attributed to the erroneous placement of a low-pressure drain placed in the pleural cavity instead of a lumbar drain; this resulted in subdural hematoma's necessitating subsequent surgery. Conclusion: Severe neurological deterioration occurring after thoracic decompressive surgery may rarely be attributed to intracranial hypotension due to a subarachnoid-pleural fistula. Patients should be treated with external lumbar drainage of cerebrospinal fluid for 3–5 days rather than a low-pressure pleural drain to avoid the onset of intracranial hypotension leading to symptomatic subdural hematomas. PMID:26005575

  11. ISABELLE vacuum systems

    SciTech Connect

    Halama, H J

    1980-01-01

    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.

  12. DENVER DISC FILTER IN CO91107, SHOWING FIVE DOUBLESIDED DISCS AND ...

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

    DENVER DISC FILTER IN CO-91-107, SHOWING FIVE DOUBLE-SIDED DISCS AND DRIVE MOTOR. NOTE FOUR VERTICAL SLURRY FEED PIPES FROM OVERHEAD MANIFOLD AND SUCTION PIPE IN FOREGROUND. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

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

    NASA Astrophysics Data System (ADS)

    Ghouchani, Azadeh; Ravari, Mohammad; Mahmoudi, Farid

    2011-10-01

    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.

  14. Reconstructing the star formation history of the Milky Way disc(s) from chemical abundances

    NASA Astrophysics Data System (ADS)

    Snaith, O.; Haywood, M.; Di Matteo, P.; Lehnert, M. D.; Combes, F.; Katz, D.; Gómez, A.

    2015-06-01

    We develop a chemical evolution model to study the star formation history of the Milky Way. Our model assumes that the Milky Way has formed from a closed-box-like system in the inner regions, while the outer parts of the disc have experienced some accretion. Unlike the usual procedure, we do not fix the star formation prescription (e.g. Kennicutt law) to reproduce the chemical abundance trends. Instead, we fit the abundance trends with age to recover the star formation history of the Galaxy. Our method enables us to recover the star formation history of the Milky Way in the first Gyrs with unprecedented accuracy in the inner (R < 7-8 kpc) and outer (R > 9-10 kpc) discs, as sampled in the solar vicinity. We show that half the stellar mass formed during the thick-disc phase in the inner galaxy during the first 4-5 Gyr. This phase was followed by a significant dip in star formation activity (at 8-9 Gyr) and a period of roughly constant lower-level star formation for the remaining 8 Gyr. The thick-disc phase has produced as many metals in 4 Gyr as the thin-disc phase in the remaining 8 Gyr. Our results suggest that a closed-box model is able to fit all the available constraints in the inner disc. A closed-box system is qualitatively equivalent to a regime where the accretion rate maintains a high gas fraction in the inner disc at high redshift. In these conditions the SFR is mainly governed by the high turbulence of the interstellar medium. By z ~ 1 it is possible that most of the accretion takes place in the outer disc, while the star formation activity in the inner disc is mostly sustained by the gas that is not consumed during the thick-disc phase and the continuous ejecta from earlier generations of stars. The outer disc follows a star formation history very similar to that of the inner disc, although initiated at z ~ 2, about 2 Gyr before the onset of the thin-disc formation in the inner disc.

  15. Improving Vacuum Cleaners

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Under a Space Act Agreement between the Kirby company and Lewis Research Center, NASA technology was applied to a commercial vacuum cleaner product line. Kirby engineers were interested in advanced operational concepts, such as particle flow behavior and vibration, critical factors to improve vacuum cleaner performance. An evaluation of the company 1994 home care system, the Kirby G4, led to the refinement of the new G5 and future models. Under the cooperative agreement, Kirby had access to Lewis' holography equipment, which added insight into how long a vacuum cleaner fan would perform, as well as advanced computer software that can simulate the flow of air through fans. The collaboration resulted in several successes including fan blade redesign and continuing dialogue on how to improve air-flow traits in various nozzle designs.

  16. Only marginal alignment of disc galaxies

    NASA Astrophysics Data System (ADS)

    Andrae, René; Jahnke, Knud

    2011-12-01

    Testing theories of angular-momentum acquisition of rotationally supported disc galaxies is the key to understanding the formation of this type of galaxies. The tidal-torque theory aims to explain this acquisition process in a cosmological framework and predicts positive autocorrelations of angular-momentum orientation and spiral-arm handedness, i.e. alignment of disc galaxies, on short distance scales of 1 Mpc h-1. This disc alignment can also cause systematic effects in weak-lensing measurements. Previous observations claimed discovering these correlations but are overly optimistic in the reported level of statistical significance of the detections. Errors in redshift, ellipticity and morphological classifications were not taken into account, although they have a significant impact. We explain how to rigorously propagate all the important errors through the estimation process. Analysing disc galaxies in the Sloan Digital Sky Survey (SDSS) data base, we find that positive autocorrelations of spiral-arm handedness and angular-momentum orientations on distance scales of 1 Mpc h-1 are plausible but not statistically significant. Current data appear not good enough to constrain parameters of theory. This result agrees with a simple hypothesis test in the Local Group, where we also find no evidence for disc alignment. Moreover, we demonstrate that ellipticity estimates based on second moments are strongly biased by galactic bulges even for Scd galaxies, thereby corrupting correlation estimates and overestimating the impact of disc alignment on weak-lensing studies. Finally, we discuss the potential of future sky surveys. We argue that photometric redshifts have too large errors, i.e. PanSTARRS and LSST cannot be used. Conversely, the EUCLID project will not cover the relevant redshift regime. We also discuss the potentials and problems of front-edge classifications of galaxy discs in order to improve the autocorrelation estimates of angular-momentum orientation.

  17. Reoperations Following Cervical Disc Replacement

    PubMed Central

    Skovrlj, Branko; Lee, Dong-Ho; Caridi, John Michael

    2015-01-01

    Cervical disc replacement (CDR) has emerged as an alternative surgical option to cervical arthrodesis. With increasing numbers of patients and longer follow-ups, complications related to the device and/or aging spine are growing, leaving us with a new challenge in the management and surgical revision of CDR. The purpose of this study is to review the current literature regarding reoperations following CDR and to discuss about the approaches and solutions for the current and future potential complications associated with CDR. The published rates of reoperation (mean, 1.0%; range, 0%-3.1%), revision (mean, 0.2%; range, 0%-0.5%), and removal (mean, 1.2%; range, 0%-1.9%) following CDR are low and comparable to the published rates of reoperation (mean, 1.7%; range; 0%-3.4%), revision (mean, 1.5%; range, 0%-4.7%), and removal (mean, 2.0%; range, 0%-3.4%) following cervical arthrodesis. The surgical interventions following CDR range from the repositioning to explantation followed by fusion or the reimplantation to posterior foraminotomy or fusion. Strict patient selection, careful preoperative radiographic review and surgical planning, as well as surgical technique may reduce adverse events and the need for future intervention. Minimal literature and no guidelines exist for the approaches and techniques in revision and for the removal of implants following CDR. Adherence to strict indications and precise surgical technique may reduce the number of reoperations, revisions, and removals following CDR. Long-term follow-up studies are needed, assessing the implant survivorship and its effect on the revision and removal rates. PMID:26097667

  18. Electrostatic Levitator Vacuum Chamber

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Optical ports ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (beam passes through the window at left), positioning lasers (one port is at center), and lamps to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  19. Debris Discs: Modeling/theory review

    NASA Astrophysics Data System (ADS)

    Thébault, P.

    2012-03-01

    An impressive amount of photometric, spectroscopic and imaging observations of circumstellar debris discs has been accumulated over the past 3 decades, revealing that they come in all shapes and flavours, from young post-planet-formation systems like Beta-Pic to much older ones like Vega. What we see in these systems are small grains, which are probably only the tip of the iceberg of a vast population of larger (undetectable) collisionally-eroding bodies, leftover from the planet-formation process. Understanding the spatial structure, physical properties, origin and evolution of this dust is of crucial importance, as it is our only window into what is going on in these systems. Dust can be used as a tracer of the distribution of their collisional progenitors and of possible hidden massive pertubers, but can also allow to derive valuable information about the disc's total mass, size distribution or chemical composition. I will review the state of the art in numerical models of debris disc, and present some important issues that are explored by current modelling efforts: planet-disc interactions, link between cold (i.e. Herschel-observed) and hot discs, effect of binarity, transient versus continuous processes, etc. I will finally present some possible perspectives for the development of future models.

  20. Metallicity, planet formation, and disc lifetimes

    E-print Network

    Ercolano, Barbara

    2009-01-01

    The formation of planets within a disc must operate within the time frame of disc dispersal, it is thus crucial to establish what is the dominant process that disperses the gaseous component of discs around young stars. Planet formation itself as well as photoevaporation by energetic radiation from the central young stellar object have been proposed as plausible dispersal mechanisms. [abridged]. In this paper we use the different metallicity dependance of X-ray photoevaporation and planet formation to discriminate between these two processes. We study the effects of metallicity, Z, on the dispersal timescale, t_phot, in the context of a photoevaporation model, by means of detailed thermal calculations of a disc in hydrostatic equilibrium irradiated by EUV and X-ray radiation from the central source. Our models show t_phot \\propto Z^0.52 for a pure photoevaporation model. By means of analytical estimates we derive instead a much stronger negative power dependance on metallicity of the disc lifetime for a dispe...

  1. Genetic aspects of intervertebral disc degeneration.

    PubMed

    Hanaei, Sara; Abdollahzade, Sina; Khoshnevisan, Alireza; Kepler, Christopher K; Rezaei, Nima

    2015-10-01

    Intervertebral disc degeneration (IVDD) is one of the common causes of low back pain. Similar to many other multifactorial diseases, it is affected by environmental and genetic factors. Although not completely understood, genetic factors include a wide spectrum of variations, such as single nucleotide polymorphisms, which could play a significant role in the etiology of this disease. Besides, the interactions with environmental factors could make the role of genetic factors more complicated. Genetic variations in disc components could participate in developing degenerative disc disease through altering the normal homeostasis of discs. Gene polymorphisms in disc proteins (collagens I, II, III, IX, and XI), proteoglycans (aggrecan), cytokines (interleukins I, VI, and X), enzymes (matrix metalloproteinases II, III, and IX), and vitamin D receptor seem to play considerable roles in the pathology of this disease. There are also many other investigated genes that could somehow take part in the process. However, it seems that more studies are needed to clarify the exact role of genetics in IVDD. PMID:25996483

  2. The quantum vacuum

    E-print Network

    Paraoanu, G S

    2014-01-01

    The vacuum is the lowest energy state of a field in a certain region of space. This definition implies that no particles can be present in the vacuum state. In classical physics, the only features of vacuum are those of its geometry. For example, in the general theory of relativity the geometry is a dynamical structure that guides the motion of matter, and, in turn, it is bent and curved by the presence of matter. Other than this, the classical vacuum is a structure void of any physical properties, since classically properties are strictly associated with physical objects such as particles and finite-amplitude fields. The situation is very different in quantum physics. As I will show in this paper, the difference stems form the fact that in quantum physics the properties are not strictly tied to objects. We know for example that physical properties come into existence - as values of observables - only when the object is measured. Thus, quantum physics allows us to detach properties from objects. This has cons...

  3. The vacuum conservation theorem

    E-print Network

    E. Minguzzi

    2015-02-28

    A version of the vacuum conservation theorem is proved which does not assume the existence of a time function nor demands stronger properties than the dominant energy condition. However, it is shown that a stronger stable version plays a role in the study of compact Cauchy horizons.

  4. Langmuir vacuum and superconductivity

    SciTech Connect

    Veklenko, B. A.

    2012-06-15

    It is shown that, in the 'jelly' model of cold electron-ion plasma, the interaction between electrons and the quantum electromagnetic vacuum of Langmuir waves involves plasma superconductivity with an energy gap proportional to the energy of the Langmuir quantum.

  5. The vacuum conservation theorem

    NASA Astrophysics Data System (ADS)

    Minguzzi, E.

    2015-03-01

    A version of the vacuum conservation theorem is proved which does not assume the existence of a time function nor demands stronger properties than the dominant energy condition. However, it is shown that a stronger stable version plays a role in the study of compact Cauchy horizons.

  6. Is our vacuum stable?

    E-print Network

    E. I. Guendelman; J. Portnoy

    2000-04-04

    The stability of our vacuum is analyzed and several aspects concerning this question are reviewed. 1) In the standard Glashow-Weinberg-Salam (GWS) model we review the instability towards the formation of a bubble of lower energy density and how the rate of such bubble formation process compares with the age of the Universe for the known values of the GWS model. 2) We also review the recent work by one of us (E.I.G) concerning the vacuum instability question in the context of a model that solves the cosmological constant problem. It turns out that in such model the same physics that solves the cosmological constant problem makes the vacuum stable. 3) We review our recent work concerning the instability of elementary particle embedded in our vacuum, towards the formation of an infinite Universe. Such process is not catastrophic. It leads to a "bifurcation type" instability in which our Universe is not eaten by a bubble (instead a baby universe is born). This universe does not replace our Universe rather it disconnects from it (via a wormhole) after formation.

  7. Topics in vacuum decay

    NASA Astrophysics Data System (ADS)

    Masoumi, Ali

    2013-12-01

    If a theory has more than one classically stable vacuum, quantum tunneling and thermal jumps make the transition between the vacua possible. The transition happens through a first order phase transition started by nucleation of a bubble of the new vacuum. The outward pressure of the truer vacuum makes the bubble expand and consequently eat away more of the old phase. In the presence of gravity this phenomenon gets more complicated and meanwhile more interesting. It can potentially have important cosmological consequences. Some aspects of this decay are studied in this thesis. Solutions with different symmetry than the generically used O(4) symmetry are studied and their actions calculated. Vacuum decay in a spatial vector field is studied and novel features like kinky domain walls are presented. The question of stability of vacua in a landscape of potentials is studied and the possible instability in large dimension of fields is shown. Finally a compactification of the Einstein-Maxwell theory is studied which can be a good lab to understand the decay rates in compactification models of arbitrary dimensions.

  8. Generation of highly inclined protoplanetary discs through single stellar flybys

    NASA Astrophysics Data System (ADS)

    Xiang-Gruess, M.

    2016-01-01

    We study the three-dimensional evolution of a viscous protoplanetary disc which is perturbed by a passing star on a parabolic orbit. The aim is to test whether a single stellar flyby is capable to excite significant disc inclinations which would favour the formation of so-called misaligned planets. We use smoothed particle hydrodynamics to study inclination, disc mass and angular momentum changes of the disc for passing stars with different masses. We explore different orbital configurations for the perturber's orbit to find the parameter spaces which allow significant disc inclination generation. Prograde inclined parabolic orbits are most destructive leading to significant disc mass and angular momentum loss. In the remaining disc, the final disc inclination is only below 20°. This is due to the removal of disc particles which have experienced the strongest perturbing effects. Retrograde inclined parabolic orbits are less destructive and can generate disc inclinations up to 60°. The final disc orientation is determined by the precession of the disc angular momentum vector about the perturber's orbital angular momentum vector and by disc orbital inclination changes. We propose a sequence of stellar flybys for the generation of misalignment angles above 60°. The results taken together show that stellar flybys are promising and realistic for the explanation of misaligned Hot Jupiters with misalignment angles up to 60°.

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    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.

  10. Vacuum requirements for RHIC

    SciTech Connect

    Rhoades-Brown, M.J.; Harrison, M.

    1991-12-01

    In this note the lifetime due to inelastic scattering of beam and residual gas ions is calculated in units of pressure (Torr). In addition, the transverse emittance growth due to elastic scattering is expressed in units of pressure. The definition of inelastic scattering includes both capture of an electron from a residual gas ion and central nuclear collisions between beam ion and gas atom. Emittance growth via elastic scattering is a simple consequence of multiple Coulomb scattering. Is is important to note that in an accelerator only the density of residual gas atoms is relevant to the machine operation. The measure of this density is the vacuum gauge, where this gauge is calibrated in pressure units at some known temperature T{sub G}. The vacuum unit or pressure is of course temperature dependent, and thus when quoting vacuum requirements for RHIC it is vital to state the temperature at which the pressure is computed. It might be necessary to scale any computed gas density to the pressure appropriate for the measurement with the vacuum gauge. Typically, the vacuum gauge operates at room temperature {approximately}300{degree}K. An explanation on how to rescale pressure as a function of temperature is given in the text. This note assumes the residual gas density in the so-called warm section (300{degree}K) of RHIC to be composed of 90% H{sub 2}, 5% CH{sub 4} and 5% CO. The gas in the cold section (5{degree}K) is assumed to be 100% He. The beam ions are taken to be {sup 197}Au{sup 79+}.

  11. Demonstrations with a Vacuum: Old Demonstrations for New Vacuum Pumps.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1989-01-01

    Explains mechanisms of 19th-century vacuum pumps. Describes demonstrations using the pump including guinea and feather tube, aurora tube, electric egg, Gassiots cascade, air mill, bell in vacuum, density and buoyancy of air, fountain in vacuum, mercury shower, palm and bladder glasses, Bacchus demonstration, pneumatic man-lifter, and Magdeburg…

  12. Disc in flames: Roles of TNF-? and IL-1? in intervertebral disc degeneration.

    PubMed

    Johnson, Z I; Schoepflin, Z R; Choi, H; Shapiro, I M; Risbud, M V

    2015-01-01

    The intervertebral disc is an important mechanical structure that allows range of motion of the spinal column. Degeneration of the intervertebral disc--incited by aging, traumatic insult, genetic predisposition, or other factors--is often defined by functional and structural changes in the tissue, including excessive breakdown of the extracellular matrix, increased disc cell senescence and death, as well as compromised biomechanical function of the tissue. Intervertebral disc degeneration is strongly correlated with low back pain, which is a highly prevalent and costly condition, significantly contributing to loss in productivity and health care costs. Disc degeneration is a chronic, progressive condition, and current therapies are limited and often focused on symptomatic pain relief rather than curtailing the progression of the disease. Inflammatory processes exacerbated by cytokines tumour necrosis factor-? (TNF-?) and interleukin-1? (IL-1?) are believed to be key mediators of disc degeneration and low back pain. In this review, we describe the contributions of TNF-? and IL-1? to changes seen during disc degeneration at both cellular and tissue level, as well as new evidence suggesting a link between infection of the spine and low back pain, and the emerging therapeutic modalities aimed at combating these processes. PMID:26388614

  13. Magnetically driven accretion in protoplanetary discs

    NASA Astrophysics Data System (ADS)

    Simon, Jacob B.; Lesur, Geoffroy; Kunz, Matthew W.; Armitage, Philip J.

    2015-11-01

    We characterize magnetically driven accretion at radii between 1 and 100 au in protoplanetary discs, using a series of local non-ideal magnetohydrodynamic (MHD) simulations. The simulations assume a minimum mass solar nebula (MMSN) disc that is threaded by a net vertical magnetic field of specified strength. Confirming previous results, we find that the Hall effect has only a modest impact on accretion at 30 au, and essentially none at 100 au. At 1-10 au the Hall effect introduces a pronounced bimodality in the accretion process, with vertical magnetic fields aligned to the disc rotation supporting a strong laminar Maxwell stress that is absent if the field is anti-aligned. In the anti-aligned case, we instead find evidence for bursts of turbulent stress at 5-10 au, which we tentatively identify with the non-axisymmetric Hall-shear instability. The presence or absence of these bursts depends upon the details of the adopted chemical model, which suggests that appreciable regions of actual protoplanetary discs might lie close to the borderline between laminar and turbulent behaviour. Given the number of important control parameters that have already been identified in MHD models, quantitative predictions for disc structure in terms of only radius and accretion rate appear to be difficult. Instead, we identify robust qualitative tests of magnetically driven accretion. These include the presence of turbulence in the outer disc, independent of the orientation of the vertical magnetic fields, and a Hall-mediated bimodality in turbulent properties extending from the region of thermal ionization to 10 au.

  14. Furnace brazing under partial vacuum

    NASA Technical Reports Server (NTRS)

    Mckown, R. D.

    1979-01-01

    Brazing furnace utilizing partial-vacuum technique reduces tooling requirements and produces better bond. Benefit in that partial vacuum helps to dissociate metal oxides that inhibit metal flow and eliminates heavy tooling required to hold parts together during brazing.

  15. Tritium handling in vacuum systems

    SciTech Connect

    Gill, J.T.; Coffin, D.O.

    1986-10-01

    This report provides a course in Tritium handling in vacuum systems. Topics presented are: Properties of Tritium; Tritium compatibility of materials; Tritium-compatible vacuum equipment; and Tritium waste treatment.

  16. Vacuum Energy in Quantum Graphs 

    E-print Network

    Wilson, Justin

    2007-07-14

    We calculate the vacuum energy in quantum graphs. Vacuum energy arose in quantum physics but has an independent mathematical interest as a functional carrying information about the eigenvalue spectrum of a system. A quantum graph is a metric graph...

  17. Dielectric Theory of the Vacuum

    E-print Network

    J. X. Zheng-Johansson

    2006-12-11

    The vacuum is proposed to be a dielectric medium constituted of neutral but polarizable vacuuons based on overall experimental observations in separate publications. In the present paper I formally develop the dielectric theory for this dielectric vacuum.

  18. Two-level total lumbar disc replacement

    PubMed Central

    Bakaloudis, Georgios; Lolli, Francesco; Vommaro, Francesco; Parisini, Patrizio

    2009-01-01

    Total lumbar disc replacement (TDR) has been widely used as a treatment option for 2-level symptomatic degenerative disc disease. However, recent studies have presented conflicting results and some authors concluded that outcome deteriorated when disc replacement was performed bisegmentally, with an increase of complications for bisegmental replacements in comparison with monosegmental disc arthroplasty. The goal of the present retrospective study is to investigate results in a group of patients who have received bisegmental TDR with SB Charitè III artificial disc for degenerative disc disease with a minimum follow-up of 3 years, and to compare the results of 2-level disc replacement versus 1-level patients treated with the same prosthesis. A total of 32 patients had at least 3-years follow-up and were reviewed. The average age of the patients was 38.5 years. There were 11 males and 21 females. About 16 patients received 2-level TDR (SB Charitè III) and 16 received 1-level TDR (SB Charitè III). Both radiographic and functional outcome analysis, including patient’s satisfaction, was performed. There were no signs of degenerative changes of the adjacent segments in any case of the 2- or 1-level TDR. There was no statistically significant difference between 2- and 1-level TDR both at 12 months and at 3-years follow-up on functional outcome scores. There was a statistically insignificant difference concerning the patients satisfaction between 1- and 2-level surgeries at the last follow-up (P = 0.46). In the 2-level TDR patients, there were 5 minor complications (31.25%), whereas major complications occurred in 4 more patients (25%) and required a new surgery in 2 cases (12.5%). In the 1-level cases there were 2 minor complications (12.5%) and 2 major complications (12.5%) and a new revision surgery was required in 1 patient (6.25%). In conclusion, the use of 2-level disc replacement at last follow-up presented a higher incidence of complications than in cases with 1-level replacement. At the same time it was impossible to delineate a clear difference in evaluating the questionnaires between the follow-up results of patients receiving 2- and 1-level TDR: the 2-level group presented slightly lower scores at follow-up, but none was statistically significant. PMID:19399536

  19. Disc valve for sampling erosive process streams

    DOEpatents

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

    1986-01-07

    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.

  20. Intervertebral disc degeneration: evidence for two distinct phenotypes

    PubMed Central

    Adams, Michael A; Dolan, Patricia

    2012-01-01

    We review the evidence that there are two types of disc degeneration. ‘Endplate-driven’ disc degeneration involves endplate defects and inwards collapse of the annulus, has a high heritability, mostly affects discs in the upper lumbar and thoracic spine, often starts to develop before age 30 years, usually leads to moderate back pain, and is associated with compressive injuries such as a fall on the buttocks. ‘Annulus-driven’ disc degeneration involves a radial fissure and/or a disc prolapse, has a low heritability, mostly affects discs in the lower lumbar spine, develops progressively after age 30 years, usually leads to severe back pain and sciatica, and is associated with repetitive bending and lifting. The structural defects which initiate the two processes both act to decompress the disc nucleus, making it less likely that the other defect could occur subsequently, and in this sense the two disc degeneration phenotypes can be viewed as distinct. PMID:22881295

  1. A radiation hard vacuum switch

    DOEpatents

    Boettcher, G.E.

    1988-07-19

    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.

  2. Difficult to process? Vacuum it!

    SciTech Connect

    Eckles, A.J.

    1997-09-01

    Recent improvements in vacuum processing have broadened the technology`s use in the chemical process industries, running the gamut from vacuum distillation and evaporation, degassing, freeze drying, vapor deposition and etching, to vacuum filtrations. The paper discusses process improvements, attaining liquid distribution, medium-vacuum processing, falling-film evaporators, wiped-film evaporators, short-path evaporators, evaporation and crystallization, filtration, drying, refrigeration, freeze drying, degassing, semiconductor processing, pumps and their selection, and leak testing.

  3. Clinical measurement and categorization of optic disc in glaucoma patients

    PubMed Central

    Rao, Harsha B L; Sekhar, G C; Babu, Ganesh J; Parikh, Rajul S

    2009-01-01

    Background: Assessment of optic disc size is an important component of optic nerve head examination. Agreement between different methods of disc size measurements is not very good. Purpose: To assess the agreement between the disc size assessed by Heidelberg retina tomograph (HRT) and stereobiomicroscopy with a 90 diopter (D) lens. To report the clinical (measured by biomicroscopy) disc diameters of small, average and large optic discs categorized by HRT disc areas. Setting and Design: Observational study of subjects examined in the glaucoma clinic of a tertiary eye institute. Materials and Methods: Seventy-five eyes of 75 glaucoma subjects were studied. Disc diameter was measured using stereobiomicroscopy and HRT. The agreement between the two sets of measurements was assessed by intraclass correlation coefficient (ICC). Discs were classified into small (<1.6 mm2), average (1.6-2.6 mm2) and large (>2.6 mm2) depending on cutoffs provided by the manufacturers of HRT. The means (95% CI) of the corresponding vertical disc diameter in these groups were assessed. Statistical Analysis: ICC, Bland and Altman plots. Results: ICC for measurements of clinical and HRT horizontal disc diameter was 0.518 and for vertical disc diameter measurement was 0.487. The mean difference between the clinical and HRT measurements as analyzed by the Bland and Altman plot was 0.17 (95% CI, 0.13- 0.47) for horizontal and 0.22 (95% CI, 0.11- 0.54) for vertical disc diameter. Of the 75 eyes, 3 eyes had small discs, 54 average and 18 large discs. The mean clinical vertical disc diameter for small discs was 1.55 mm (95% CI, 1.2-1.7), for average discs was 1.91 mm (95% CI, 1.87-1.96) and for large discs was 2.15 mm (95% CI, 2.03–2.27). Conclusion: The agreement between clinical and HRT disc diameter measurements is moderate. Disc diameter measurement on stereobiomicroscopy can be used to categorize discs into small, average and large discs. PMID:19700874

  4. Portable vacuum object handling device

    DOEpatents

    Anderson, Gordon H. (Los Alamos, NM)

    1983-08-09

    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.

  5. Casimir effect and vacuum energy

    E-print Network

    Cyriaque Genet; Astrid Lambrecht; Serge Reynaud

    2002-10-25

    Vacuum fluctuations have observable consequences, like the Casimir force appearing between two mirrors in vacuum. This force is now measured with good accuracy and agreement with theory. We discuss the meaning and consequences of these statements by emphasizing their relation with the problem of vacuum energy, one of the main unsolved problems at the interface between gravitational and quantum theory.

  6. E ective geometry Casimir vacuum

    E-print Network

    Visser, Matt

    E#11;ective geometry in the Casimir vacuum Matt Visser Physics Department Washington University- hibit anomalous propagation in the Casimir vac- uum (the quantum vacuum between perfectly conducting the Casimir vacuum: A region of empty space delimited by two per- fectly conducting parallel plates

  7. Interactive Optical Disc Systems: Part 1: Analog Storage.

    ERIC Educational Resources Information Center

    Hessler, David W.

    1984-01-01

    Details distinction between digital and analog data, advantages of analog storage, and optical disc use to store analog data. Configuration and potential of three levels of laser disc systems are explained. Selection of display devices for use with laser disc systems and accessing audio data are addressed. (Continued in next issue.) (EJS)

  8. DISC1–ATF4 transcriptional repression complex: dual regulation of the cAMP-PDE4 cascade by DISC1

    E-print Network

    Ishizuka, K

    Disrupted-In-Schizophrenia 1 (DISC1), a risk factor for major mental illnesses, has been studied extensively in the context of neurodevelopment. However, the role of DISC1 in neuronal signaling, particularly in conjunction ...

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

    PubMed

    Srinivas, Shreya; Shetty, Rohit; Collins, Iona

    2012-06-01

    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

  10. Compact vacuum insulation embodiments

    DOEpatents

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

    1992-01-01

    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.

  11. Compact vacuum insulation

    DOEpatents

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

    1993-01-01

    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.

  12. Compact vacuum insulation

    DOEpatents

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

    1993-01-05

    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.

  13. Compact vacuum insulation embodiments

    DOEpatents

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

    1992-04-28

    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. 26 figs.

  14. Electrostatic Levitator Vacuum Chamber

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Optical prots ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (the beam passes through the window at left), poisitioning lasers (one port is at center), and lamps (arc lamp at right), and to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  15. Electrostatic Levitator Vacuum Chambers

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Optical prots ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (the beam passes through the window at left), poisitioning lasers (one port is at center), and lamps (such as the deuterium arc lamp at right), and to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  16. Vacuum tool manipulator

    DOEpatents

    Zollinger, W.T.

    1993-11-23

    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.

  17. Vacuum tool manipulator

    DOEpatents

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

    1993-01-01

    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.

  18. Vacuum Structure and Potential

    E-print Network

    J. X. Zheng-Johansson

    2007-04-02

    Based on overall experimental observations, especially the pair processes, I developed a model structure of the vacuum along with a basic-particle formation scheme begun in 2000 (with collaborator P-I Johansson). The model consists in that the vacuum is, briefly, filled of neutral but polarizable vacuuons, consisting each of a p-vaculeon and n- vaculeon of charges $+e$ and $-e$ of zero rest masses but with spin motions, assumed interacting each other with a Coulomb force. The model has been introduced in full in a book (Nova Sci, 2005) and referred to in a number of journal/E-print papers. I outline in this easier accessible paper the detailed derivation of the model and a corresponding quantitative determination of the vacuuon size.

  19. Dry vacuum pumps

    NASA Astrophysics Data System (ADS)

    Sibuet, R.

    2008-05-01

    For decades and for ultimate pressure below 1 mbar, oil-sealed Rotary Vane Pumps have been the most popular solution for a wide range of vacuum applications. In the late 80ies, Semiconductor Industry has initiated the development of the first dry roughing pumps. Today SC applications are only using dry pumps and dry pumping packages. Since that time, pumps manufacturers have developed dry vacuum pumps technologies in order to make them attractive for other applications. The trend to replace lubricated pumps by dry pumps is now spreading over many other market segments. For the Semiconductor Industry, it has been quite easy to understand the benefits of dry pumps, in terms of Cost of Ownership, process contamination and up-time. In this paper, Technology of Dry pumps, its application in R&D/industries, merits over conventional pumps and future growth scope will be discussed.

  20. The vacuum energy crisis

    E-print Network

    Alexander Vilenkin

    2006-05-09

    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).

  1. Prognosis of intervertebral disc loss from diagnosis of degenerative disc disease

    NASA Astrophysics Data System (ADS)

    Li, S.; Lin, A.; Tay, K.; Romano, W.; Osman, Said

    2015-03-01

    Degenerative Disc Disease (DDD) is one of the most common causes of low back pain, and is a major factor in limiting the quality of life of an individual usually as they enter older stages of life, the disc degeneration reduces the shock absorption available which in turn causes pain. Disc loss is one of the central processes in the pathogenesis of DDD. In this study, we investigated whether the image texture features quantified from magnetic resonance imaging (MRI) could be appropriate markers for diagnosis of DDD and prognosis of inter-vertebral disc loss. The main objective is to use simple image based biomarkers to perform prognosis of spinal diseases using non-invasive procedures. Our results from 65 subjects proved the higher success rates of the combination marker compared to the individual markers and in the future, we will extend the study to other spine regions to allow prognosis and diagnosis of DDD for a wider region.

  2. Reappraisal of the ratio of disc to macula/disc diameter in optic nerve hypoplasia.

    PubMed Central

    Zeki, S M; Dudgeon, J; Dutton, G N

    1991-01-01

    The ratio of disc to macula/disc diameter is characteristically increased in eyes with optic nerve hypoplasia. We present the largest reported series of patients with a definitive diagnosis of optic nerve hypoplasia for whom this ratio has been determined. All measurements were made by an independent masked observer. Our results are in accordance with previous reports. A ratio of 2.94 provides a one-tailed upper population limit of 95%. An attempt has been made to correlate optic disc size and visual acuity. In 75% of bilateral cases the eye with the relatively smaller optic disc was found to have a better Snellen visual acuity than the fellow eye. This suggests that additional pathogenic mechanism(s) may have determined the eventual visual outcome in such eyes. Such mechanisms include macular hypoplasia, high refractive error, refractive amblyopia, central scotoma, and optic atrophy. Images PMID:1911656

  3. The ITER vacuum systems

    NASA Astrophysics Data System (ADS)

    Day, C.; Murdoch, D.

    2008-05-01

    ITER is a large vacuum facility which comprises many service, diagnostic and monitoring vacuum sub-systems as well as three large cryogenic pumping systems for evacuation and maintenance of the required pressure levels. Control of the gas throughput is one of the key issues affecting the performance and achievable burn time of a fusion reactor. The main pumping systems are the torus exhaust pumping, the cryopumps for the neutral beam injection systems for plasma heating, and the cryopumps for the ITER cryostat. All customized cryosorption pumps are force-cooled with supercritical helium and share a similar modular design of cryosorption pumping panels. For regeneration of the cryopumps as well as for roughing down the system volumes prior to operation, four identical sets of forepump trains are used. This paper will focus on the areas of the ITER vacuum systems which require customized developments and cannot rely on commercial solutions. The complex pumps have been tailored for the very specific applications and requirements at ITER, especially characterised by the need to be tritium compatible. An outline of the development path which was needed to come up with a sound design for the ITER cryopumps is given. The way of development is culminating in the manufacturing of 1:1 scale prototypes, which will be extensively tested in dedicated test facilities to ensure compatibility with all design requirements.

  4. The LHC Vacuum System

    NASA Astrophysics Data System (ADS)

    Gröbner, O.

    1997-05-01

    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'.

  5. AIRS Data Products at GES DISC DAAC

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This list contains the names and some characteristics of Atmospheric InfraRed Sounder (AIRS) data products at the Goddard Earth Sciences (GES) Data and Information Services Center (DISC) Distributed Active Archive Center (DAAC). The list includes variables, units, dimensions, and descriptions for each of the data products, which include infrared radiances and brightness temperatures.

  6. DISC-BASED IMMUNOASSAY MICROARRAYS. (R825433)

    EPA Science Inventory

    Microarray technology as applied to areas that include genomics, diagnostics, environmental, and drug discovery, is an interesting research topic for which different chip-based devices have been developed. As an alternative, we have explored the principle of compact disc-based...

  7. The Astral Curved Disc of Chevroches (France)

    NASA Astrophysics Data System (ADS)

    Devevey, F. Rousseau, A.

    2009-08-01

    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.

  8. On the convective overstability in protoplanetary discs

    NASA Astrophysics Data System (ADS)

    Latter, Henrik N.

    2016-01-01

    This paper explores the driving of low-level hydrodynamical activity in protoplanetary-disc dead zones. A small adverse radial entropy gradient, ordinarily stabilized by rotation, excites oscillatory convection (`convective overstability') when thermal diffusion, or cooling, is neither too strong nor too weak. I revisit the linear theory of the instability, discuss its prevalence in protoplanetary discs, and show that unstable modes are exact non-linear solutions in the local Boussinesq limit. Overstable modes cannot grow indefinitely, however, as they are subject to a secondary parametric instability that limits their amplitudes to relatively low levels. If parasites set the saturation level of the ensuing turbulence then the convective overstability is probably too weak to drive significant angular momentum transport or to generate vortices. But I also discuss an alternative, and far more vigorous, saturation route that generates radial `layers' or `zonal flows' (witnessed in semiconvection). Numerical simulations are required to determine which outcome is favoured in realistic discs, and consequently how important the instability is for disc dynamics.

  9. Project DISC: Developing Indian Software Curriculum.

    ERIC Educational Resources Information Center

    Jacobi, Carolyn

    Project DISC (Developing Indian Software Curriculum) was initiated in the Rapid City (South Dakota) school district to improve Native American children's reading and language arts ability and to provide them with microcomputer skills. During the summer of 1982, introductory computer activities were planned, a computer specialist was hired, and…

  10. Infrared variability from circumbinary disc temperature modulations

    NASA Astrophysics Data System (ADS)

    Bodman, Eva H. L.; Quillen, Alice

    2015-11-01

    The temperature of a circumbinary disc edge should undulate due to variations in illumination as a function of binary orbital phase. We explore circumbinary disc temperature variations as a source of broad-band infrared light-curve variability. Approximating the wall of a circumbinary disc edge as a wide optically thick cylinder with surface temperature dependent on its illumination, we find that a binary composed of 1 and 0.5 M? pre-main-sequence stars in a ˜15.5 d period, would exhibit the largest amplitude variations of ˜9 per cent at 3.77 and 4.68 ?m as seen by a distant observer. The amplitude of variations and shape of the light curve are sensitive to the luminosity and mass ratios of the stars in the binary, the radius of the circumbinary disc clearing, the binary separation, and the orbital inclination. The light-curve variations are smooth and very red with a non-sinusoidal shape for most of the parameter space explored. Possible morphologies include a single peak with a flat region, two peaks of different heights, or a single dip.

  11. Spectra of thermally unstable slim discs

    E-print Network

    Ewa Szuszkiewicz; Roberto Turolla; Luca Zampieri

    2000-11-21

    Thermal instability driven by radiation pressure might be relevant for intrinsically bright accreting sources. The most promising candidate where this instability seems to be at work is one of the two known galactic superluminal sources, GRS 1915+105 (Belloni et al. 1997). In spite of being of relevance, this scenario has not yet been confirmed by proper time-dependent modelling. Non-linear time-dependent calculations performed by Szuszkiewicz and Miller (1998) show that thermally unstable discs undergo limit-cycle behaviour with successive evacuation and refilling of the central parts of the disc. This evolution is very similar to the one proposed by Belloni et al. (1997) in their phenomenological model. Further investigations are needed to confirm the thermal instability being operational in this source. First of all the spectra emitted from the disc during its evolution should be calculated and compared with observations. Here such spectra are computed assuming local blackbody emission from the best studied transonic disc model.

  12. Frictional Torque on a Rotating Disc

    ERIC Educational Resources Information Center

    Mungan, Carl E.

    2012-01-01

    Resistance to motion often includes a dry frictional term independent of the speed of an object and a fluid drag term varying linearly with speed in the viscous limit. (At higher speeds, quadratic drag can also occur.) Here, measurements are performed for an aluminium disc mounted on bearings that is given an initial twist and allowed to spin…

  13. Disc valve for sampling erosive process streams

    DOEpatents

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

    1984-08-16

    This is a patent for a disc-type, four-port sampling valve for service with erosive high temperature process streams. Inserts and liners of ..cap alpha..-silicon carbide respectively, in the faceplates and in the sampling cavities, limit erosion while providing lubricity for a smooth and precise operation. 1 fig.

  14. Evolution of gas in debris discs

    NASA Astrophysics Data System (ADS)

    Kral, Quentin; Wyatt, Mark; Pringle, Jim

    2015-12-01

    A non negligible quantity of gas has been discovered in an increasing number of debris disc systems. ALMA high sensitivity and high resolution is changing our perception of the gaseous component of debris discs as CO is discovered in systems where it should be rapidly photodissociated. It implies that there is a replenishment mechanism and that the observed gas is secondary. Past missions such as Herschel probed the atomic part of the gas through O I and C II emission lines. Gas science in debris discs is still in its infancy, and these new observations raise a handful of questions concerning the mechanisms to create the gas and about its evolution in the planetary system when it is released. The latter question will be addressed in this talk as a self-consistent gas evolution scenario is proposed and is compared to observations for the peculiar case of ? Pictoris.Our model proposes that carbon and oxygen within debris discs are created due to photodissociation of CO which is itself created from the debris disc dust (due to grain-grain collisions or photodesorption). The evolution of the carbon atoms is modelled as viscous spreading, with viscosity parameterised using an ? model. The temperature, ionisation fraction and population levels of carbon are followed with a PDR model called Cloudy, which is coupled to the dynamical viscous ? model. Only carbon gets ionised due to its lower ionisation potential than oxygen. The carbon gas disc can end up with a high ionisation fraction due to strong FUV radiation field. A high ionisation fraction means that the magnetorotational instability (MRI) is very active, so that ? is very high. Gas density profiles can be worked out for different input parameters such as the ? value, the CO input rate, the location of the input and the incoming radiation field. Observability predictions can be made for future observations, and our model is tested on ? Pictoris observations. This new gas evolution model fits the carbon and CO observations in ? Pic and gives a self-consistent scenario that might be at play in all debris discs...

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

    PubMed Central

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

    1997-01-01

    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

  16. Influence of blade profile of disc cutter on numerical simulation of the disc slitting process

    NASA Astrophysics Data System (ADS)

    Zeng, J.; Lu, J. B.; Yan, Q. S.; Li, S.

    2015-03-01

    The disc slitting machining experiments for electrical steel sheet were conducted to investigate the wear process of carbide alloy disc cutter and the slitting quality in the disc slitting process, and the blade contour shape of disc cutter in different slitting distance was measured by the surface profiler. A DEFORM-2D model, where the real blade profile or arc fitting profile was used as the blade contour of the cutter, was built to simulate the disc slitting process. Results show that the blade wear of disc cutter increases. The blade wear presents uneven in the side surface and cylindrical surface of the cutter, and the side wear is more serious with the increase of the slitting distance of electrical steel sheet. As the blade wear increases, the height of the rollover increases gradually, the height of the shear area increases at first and then decreases, but the height of the fracture area decreases at first and then increases. Compared with the arc fitting profile, the simulation surface morphology using the real blade profile is in good agreement with the experimental result. The variation of blade profile can change the distribution of the hydrostatic stress of sheet metal and the occurring and propagating of the crack, and the maximum hydrostatic stress can be used to estimate the change tendency of the fracture area.

  17. Collisional dust avalanches in debris discs

    E-print Network

    Anna Grigorieva; Pawel Artymowicz; Philippe Thébault

    2006-09-26

    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.

  18. “Spontaneous” CSF Fistula due to Transtegmental Brain Herniation in Combination with Signs of Increased Intracranial Pressure and Petrous Bone Hyperpneumatization: An Illustrative Case Report

    PubMed Central

    Rivera, Diones; Fermin-Delgado, Rafael; Stoeter, Peter

    2014-01-01

    Background and Importance?Transtegmental brain herniation into the petrous bone is a rare cause of rhinoliquorrhea. Our case presents a combination of several typical clinical and imaging findings illustrating the ongoing etiologic discussion of such cerebrospinal fluid (CSF) fistulas. Clinical Presentation?A 53-year-old man presented with nasal discharge after a strong effort to suppress coughing. Imaging revealed a transtegmental herniation of parts of the inferior temporal gyrus into the petrous bone and in addition a combination of signs of chronically increased intracranial pressure and a hyperpneumatization of the petrous bone. The fistula was closed by a middle cranial fossa approach. Conclusion?The case illustrates the two main predisposing factors for development of petrous bone CSF fistulas: increased intracranial pressure and thinning of the tegmental roof due to extensive development of air cells. Because the CSF leakage repair does not change the underlying cause, patients have to be informed about the possibility of developing increased intracranial pressure and recurrences of brain herniations at other sites. PMID:25485224

  19. Exploratory study for identifying systemic biomarkers that correlate with pain response in patients with intervertebral disc disorders.

    PubMed

    Weber, K T; Satoh, Shina; Alipui, D Olivier; Virojanapa, Justin; Levine, Mitchell; Sison, Cristina; Quraishi, Shaheda; Bloom, Ona; Chahine, Nadeen O

    2015-12-01

    Molecular events that drive disc damage and low back pain (LBP) may precede clinical manifestation of disease onset and can cause detrimental long-term effects such as disability. Biomarkers serve as objective molecular indicators of pathological processes. The goal of this study is to identify systemic biochemical factors as predictors of response to treatment of LBP with epidural steroid injection (ESI). Since inflammation plays a pivotal role in LBP, this pilot study investigates the effect of ESI on systemic levels of 48 inflammatory biochemical factors (cytokines, chemokines, and growth factors) and examines the relationship between biochemical factor levels and pain or disability in patients with disc herniation (DH), or other diagnoses (Other Dx) leading to low back pain, which included spinal stenosis (SS) and degenerative disc disease (DDD). Study participants (n = 16) were recruited from a back pain management practice. Pain numerical rating score (NRS), Oswestry Disability Index (ODI), and blood samples were collected pre- and at 7 to 10 days post-treatment. Blood samples were assayed for inflammatory mediators using commercial multiplex assays. Mediator levels were compared pre- and post-treatment to investigate the potential correlations between clinical and biochemical outcomes. Our results indicate that a single ESI significantly decreased systemic levels of SCGF-? and IL-2. Improvement in pain in all subjects was correlated with changes in chemokines (MCP-1, MIG), hematopoietic progenitor factors (SCGF-?), and factors that participate in angiogenesis/fibrosis (HGF), nociception (SCF, IFN-?2), and inflammation (IL-6, IL-10, IL-18, TRAIL). Levels of biochemical mediators varied based on diagnosis of LBP, and changes in pain responses and systemic mediators from pre- to post-treatment were dependent on the diagnosis cohort. In the DH cohort, levels of IL-17 and VEGF significantly decreased post-treatment. In the Other Dx cohort, levels of IL-2R?, IL-3, and SCGF-? significantly decreased post-treatment. In order to determine whether mediator changes were related to pain, correlations between change in pain scores and change in mediator levels were performed. Subjects with DH demonstrated a profile signature that implicated hematopoiesis factors (SCGF-?, GM-CSF) in pain response, while subjects with Other Dx demonstrated a biomarker profile that implicated chemokines (MCP-1, MIG) and angiogenic factors (HGF, VEGF) in pain response. Our findings provide evidence that systemic biochemical factors in patients with LBP vary by diagnosis, and pain response to treatment is associated with a unique profile of biochemical responses in each diagnosis group. Future hypothesis-based studies with larger subject cohorts are warranted to confirm the findings of this pilot exploratory study. PMID:26440592

  20. Turbulence-induced disc formation in strongly magnetized cloud cores

    NASA Astrophysics Data System (ADS)

    Seifried, D.; Banerjee, R.; Pudritz, R. E.; Klessen, R. S.

    2013-07-01

    We present collapse simulations of strongly magnetized, turbulent molecular cloud cores with masses ranging from 2.6 to 1000 M? in order to study the influence of the initial conditions on the turbulence-induced disc formation mechanism proposed recently by Seifried et al. We find that Keplerian discs are formed in all cases independently of the core mass, the strength of turbulence or the presence of global rotation. The discs appear within a few kyr after the formation of the protostar, are 50-150 au in size, and have masses between 0.05 and a few 0.1 M?. During the formation of the discs the mass-to-flux ratio stays well below the critical value of 10 for Keplerian disc formation. Hence, flux-loss alone cannot explain the formation of Keplerian discs. The formation of rotationally supported discs at such early phases is rather due to the disordered magnetic field structure and due to turbulent motions in the surroundings of the discs, two effects lowering the classical magnetic braking efficiency. Binary systems occurring in the discs are mainly formed via the disc capturing mechanism rather than via disc fragmentation, which is largely suppressed by the presence of magnetic fields.

  1. Examination of turbine discs from nuclear power plants

    SciTech Connect

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

    1982-01-01

    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.

  2. Interface Modes and Their Instabilities in Accretion Disc Boundary Layers

    E-print Network

    David Tsang; Dong Lai

    2008-12-20

    We study global non-axisymmetric oscillation modes trapped near the inner boundary of an accretion disc. Observations indicate that some of the quasi-periodic oscillations (QPOs) observed in the luminosities of accreting compact objects (neutron stars, black holes and white dwarfs) are produced in the inner-most regions of accretion discs or boundary layers. Two simple models are considered in this paper: The magnetosphere-disc model consists of a thin Keplerian disc in contact with a uniformly rotating magnetosphere with and low plasma density, while the star-disc model involves a Keplerian disc terminated at the stellar atomosphere with high density and small density scale height. We find that the interface modes at the magnetosphere-disc boundary are generally unstable due to Rayleigh-Taylor and/or Kelvin-Helmholtz instabilities. However, differential rotation of the disc tends to suppress Rayleigh-Taylor instability and a sufficiently high disc sound speed (or temperature) is needed to overcome this suppression and to attain net mode growth. On the other hand, Kelvin-Helmholtz instability may be active at low disc sound speeds. We also find that the interface modes trapped at the boundary between a thin disc and an unmagnetized star do not suffer Rayleigh-Taylor or Kelvin-Helmholtz instability, but can become unstable due to wave leakage to large disc radii and, for sufficiently steep disc density distributions, due to wave absorption at the corotation resonance in the disc. The non-axisymmetric interface modes studied in this paper may be relevant to the high-frequency QPOs observed in some X-ray binaries and in cataclysmic variables.

  3. Polymers in a Vacuum

    SciTech Connect

    Deutsch, J. M.

    2007-12-07

    In a variety of situations, isolated polymer molecules are found in a vacuum, and here we examine their properties. Angular momentum conservation is shown to significantly alter the average size of a chain and its conservation is only broken slowly by thermal radiation. For an ideal chain, the time autocorrelation for monomer position oscillates with a period proportional to chain length. The oscillations and damping are analyzed in detail. Short-range repulsive interactions suppress oscillations and speed up relaxation, but stretched chains still show damped oscillatory correlations.

  4. Polymers in a vacuum

    E-print Network

    J. M. Deutsch

    2007-06-13

    In a variety of situations, isolated polymer molecules are found in a vacuum and here we examine their properties. Angular momentum conservation is shown to significantly alter the average size of a chain and its conservation is only broken slowly by thermal radiation. The time autocorrelation for monomer position oscillates with a characteristic time proportional to chain length. The oscillations and damping are analyzed in detail. Short range repulsive interactions suppress oscillations and speed up relaxation but stretched chains still show damped oscillatory time correlations.

  5. What is vacuum?

    E-print Network

    Peter Rowlands

    2008-10-01

    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.

  6. Avoiding Death by Vacuum

    E-print Network

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

    2013-05-08

    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.

  7. R&D ERL: Vacuum

    SciTech Connect

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

    2010-01-01

    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.

  8. The avian intervertebral disc arises from rostral sclerotome and lacks a nucleus pulposus: Implications for evolution of the vertebrate disc

    PubMed Central

    Bruggeman, Bradley J.; Maier, Jennifer A.; Mohiuddin, Yasmin S.; Powers, Rae; Lo, YinTing; Guimarães-Camboa, Nuno; Evans, Sylvia M.; Harfe, Brian D.

    2012-01-01

    Deterioration of the intervertebral discs is an unfortunate consequence of aging. The intervertebral disc in mammals is composed of three parts: a jelly-like center called the nucleus pulposus, the cartilaginous annulus fibrosus and anterior and posterior endplates that attach the discs to vertebrae. In order to understand the origin of the disc, we have investigated the intervertebral region of chickens. Surprisingly, our comparison of mouse and chicken discs revealed that chicken discs lack nuclei pulposi. In addition, the notochord, which in mice forms nuclei pulposi, was found to persist as a rod-like structure and express Shh throughout chicken embryogenesis. Our fate mapping data indicates that cells originating from the rostral half of each somite are responsible for forming the avian disc while cells in the caudal region of each somite form vertebrae. A histological analysis of mammalian and non-mammalian organisms suggests that nuclei pulposi are only present in mammals. PMID:22354863

  9. LHC vacuum system

    E-print Network

    Gröbner, Oswald

    1999-01-01

    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...

  10. The LHC Vacuum System

    E-print Network

    Gröbner, Oswald

    1998-01-01

    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...

  11. Changing MFTF vacuum environment

    SciTech Connect

    Margolies, D.; Valby, L.

    1982-12-01

    The Mirror Fusion Test Facility (MFTF) vacuum vessel will be about 60m long and 10m in diameter at the widest point. The allowable operating densities range from 2 x 10/sup 9/ to 5 x 10/sup 10/ particles per cc. The maximum leak rate of 10/sup -6/ tl/sec is dominated during operation by the deliberately injected cold gas of 250 tl/sec. This gas is pumped by over 1000 square meters of cryopanels, external sorption pumps and getters. The design and requirements have changed radically over the past several years, and they are still not in final form. The vacuum system design has also changed, but more slowly and less radically. This paper discusses the engineering effort necessary to meet these stringent and changing requirements. Much of the analysis of the internal systems has been carried out using a 3-D Monte Carlo computer code, which can estimate time dependent operational pressures. This code and its use will also be described.

  12. Inflammation in intervertebral disc degeneration and regeneration

    PubMed Central

    Molinos, Maria; Almeida, Catarina R.; Caldeira, Joana; Cunha, Carla; Gonçalves, Raquel M.; Barbosa, Mário A.

    2015-01-01

    Intervertebral disc (IVD) degeneration is one of the major causes of low back pain, a problem with a heavy economic burden, which has been increasing in prevalence as populations age. Deeper knowledge of the complex spatial and temporal orchestration of cellular interactions and extracellular matrix remodelling is critical to improve current IVD therapies, which have so far proved unsatisfactory. Inflammation has been correlated with degenerative disc disease but its role in discogenic pain and hernia regression remains controversial. The inflammatory response may be involved in the onset of disease, but it is also crucial in maintaining tissue homeostasis. Furthermore, if properly balanced it may contribute to tissue repair/regeneration as has already been demonstrated in other tissues. In this review, we focus on how inflammation has been associated with IVD degeneration by describing observational and in vitro studies as well as in vivo animal models. Finally, we provide an overview of IVD regenerative therapies that target key inflammatory players. PMID:25673296

  13. On the convective overstability in protoplanetary discs

    E-print Network

    Latter, Henrik

    2015-01-01

    This paper explores the driving of low-level hydrodynamical activity in protoplanetary-disc dead zones. A small adverse radial entropy gradient, ordinarily stabilised by rotation, excites oscillatory convection (`convective overstability') when thermal diffusion, or cooling, is neither too strong nor too weak. I revisit the linear theory of the instability, discuss its prevalence in protoplanetary discs, and show that unstable modes are exact nonlinear solutions in the local Boussinesq limit. Overstable modes cannot grow indefinitely, however, as they are subject to a secondary parametric instability that limits their amplitudes to relatively low levels. If parasites set the saturation level of the ensuing turbulence then the convective overstability is probably too weak to drive significant angular momentum transport or to generate vortices. But I also discuss an alternative, and far more vigorous, saturation route that generates radial `layers' or `zonal flows' (witnessed also in semiconvection). Numerical ...

  14. Cervical disc arthroplasty: Pros and cons

    PubMed Central

    Moatz, Bradley; Tortolani, P. Justin

    2012-01-01

    Background: Cervical disc arthroplasty has emerged as a promising potential alternative to anterior cervical discectomy and fusion (ACDF) in appropriately selected patients. Despite a history of excellent outcomes after ACDF, the question as to whether a fusion leads to adjacent segment degeneration remains unanswered. Numerous US investigational device exemption trials comparing cervical arthroplasty to fusion have been conducted to answer this question. Methods: This study reviews the current research regarding cervical athroplasty, and emphasizes both the pros and cons of arthroplasty as compared with ACDF. Results: Early clinical outcomes show that cervical arthroplasty is as effective as the standard ACDF. However, this new technology is also associated with an expanding list of novel complications. Conclusion: Although there is no definitive evidence that cervical disc replacement reduces the incidence of adjacent segment degeneration, it does show other advantages; for example, faster return to work, and reduced need for postoperative bracing. PMID:22905327

  15. Material Science in Cervical Total Disc Replacement

    PubMed Central

    Pham, Martin H.; Mehta, Vivek A.; Tuchman, Alexander; Hsieh, Patrick C.

    2015-01-01

    Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation. PMID:26523281

  16. New Experiments with Spinning Metallic Discs

    NASA Astrophysics Data System (ADS)

    Mazuruk, Konstantin; Grugel, Richard N.

    2003-01-01

    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.

  17. Material Science in Cervical Total Disc Replacement.

    PubMed

    Pham, Martin H; Mehta, Vivek A; Tuchman, Alexander; Hsieh, Patrick C

    2015-01-01

    Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation. PMID:26523281

  18. Portable vacuum object handling device

    DOEpatents

    Anderson, G.H.

    1983-08-09

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

  20. Vacuum leak detector and method

    DOEpatents

    Edwards, Jr., David (7 Brown's La., Bellport, NY 11713)

    1983-01-01

    Apparatus and method for detecting leakage in a vacuum system involves a moisture trap chamber connected to the vacuum system and to a pressure gauge. Moisture in the trap chamber is captured by freezing or by a moisture adsorbent to reduce the residual water vapor pressure therein to a negligible amount. The pressure gauge is then read to determine whether the vacuum system is leaky. By directing a stream of carbon dioxide or helium at potentially leaky parts of the vacuum system, the apparatus can be used with supplemental means to locate leaks.

  1. Vacuum metastability with black holes

    NASA Astrophysics Data System (ADS)

    Burda, Philipp; Gregory, Ruth; Moss, Ian G.

    2015-08-01

    We consider the possibility that small black holes can act as nucleation seeds for the decay of a metastable vacuum, focussing particularly on the Higgs potential. Using a thin-wall bubble approximation for the nucleation process, which is possible when generic quantum gravity corrections are added to the Higgs potential, we show that primordial black holes can stimulate vacuum decay. We demonstrate that for suitable parameter ranges, the vacuum decay process dominates over the Hawking evaporation process. Finally, we comment on the application of these results to vacuum decay seeded by black holes produced in particle collisions.

  2. On the Eddington limit for relativistic accretion discs

    NASA Astrophysics Data System (ADS)

    Abolmasov, Pavel; Chashkina, Anna

    2015-12-01

    Standard accretion disc model relies upon several assumptions, the most important of which is geometrical thinness. Whenever this condition is violated, new physical effects become important such as radial energy advection and mass loss from the disc. These effects are important, for instance, for large mass accretion rates when the disc approaches its local Eddington limit. In this work, we study the upper limits for standard accretion disc approximation and find the corrections to the standard model that should be considered in any model aiming on reproducing the transition to super-Eddington accretion regime. First, we find that for thin accretion disc, taking into account relativistic corrections allows to increase the local Eddington limit by about a factor of 2 due to stronger gravity in general relativity (GR). However, violation of the local Eddington limit also means large disc thickness. To consider consequently the disc thickness effects, one should make assumptions upon the two-dimensional rotation law of the disc. For rotation frequency constant on cylinders r sin ? = const, vertical gravity becomes stronger with height on spheres of constant radius. On the other hand, effects of radial flux advection increase the flux density in the inner parts of the disc and lower the Eddington limit. In general, the effects connected to disc thickness tend to increase the local Eddington limit even more. The efficiency of accretion is however decreased by advection effects by about a factor of several.

  3. The Photoevaporation of Discs Around Young Stars in Massive Clusters

    E-print Network

    C. J. Clarke

    2007-02-05

    We present models in which the photoevaporation of discs around young stars by an external ultraviolet source (as computed by Adams et al 2004) is coupled with the internal viscous evolution of the discs. These models are applied to the case of the Orion Nebula Cluster, where the presence of a strong ultraviolet field from the central OB stars, together with a detailed census of circumstellar discs and photoevaporative flows, is well established. In particular we investigate the constraints that are placed on the initial disc properties in the ONC by the twin requirement that most stars possess a disc on a scale of a few A.U., but that only a minority ($ 0.1 M_\\odot$). The ubiquity of discs on a small scale, on the other hand, mainly constrains the timespan over which the discs have been exposed to the ultraviolet field ($< 2 $Myr). We argue that the discs that are resolved by HST represent a population of discs in which self-gravity was important at the time that the dominant central OB star switched on, but that, according to our models, self-gravity is unlikely to be important in these discs at the present time. We discuss the implications of our results for the so-called proplyd lifetime problem.

  4. Demographics of transition discs in Ophiuchus and Taurus

    NASA Astrophysics Data System (ADS)

    Najita, Joan R.; Andrews, Sean M.; Muzerolle, James

    2015-07-01

    Transition disc systems are young stars that appear to be on the verge of dispersing their protoplanetary discs. We explore the nature of these systems by comparing the stellar accretion rates dot{M}_* and disc masses Md of transition discs and normal T Tauri stars in Taurus and Ophiuchus. After controlling for the known dependences of dot{M}_* and Md on age, dot{M}_* on stellar mass and Md on the presence of stellar or substellar companions, we find that the normal T Tauri stars show a trend of dot{M}_* increasing with Md. The transition discs tend to have higher average disc masses than normal T Tauri stars as well as lower accretion rates than normal T Tauri stars of the same disc mass. These results are most consistent with the interpretation that the transition discs have formed objects massive enough to alter the accretion flow, i.e. single or multiple giant planets. Several Ophiuchus T Tauri stars that are not known transition disc systems also have very low accretion rates for their disc masses. We speculate on the possible nature of these sources.

  5. Basics of videodisc and optical disc technology

    SciTech Connect

    Paris, J.

    1983-11-01

    The optical videodisc is now being used for archival storage of photographs and for records management. The spacedisc project, co-sponsored by nasa and drew university's center for aerospace education, is a prime example of using a videodisc to store individual photographs, slides, and motion sequences with an accompanying paper index. These discs are also used in schools in an interactive individualized learning carrel under microcomputer control. Museums also are using discs as complements to exhibits as well as in cataloging and in classification, information storage and retrieval systems. Ongoing imaginative applications of the optical videodisc include surrogate travel, job performance aids, simulators, electronic malls, and travelogues. Eventually, one will see the videodisc and computer technology with artificial intelligence programs used by the medical community and others. Optical disc and videodisc technology have opened up new horizons for information processing, storage and retrieval, education and training. Regardless of whether a mass consumer market materializes, optical recording technology will play a major role in the future design and development of information systems in the late 1980s and beyond.

  6. Gradient composite materials for artificial intervertebral discs.

    PubMed

    Migacz, Katarzyna; Ch?opek, Jan; Morawska-Chochó?, Anna; Ambroziak, Maciej

    2014-01-01

    Composites with the gradient of Young's modulus constitute a new group of biomimetic materials which affect the proper distribution of stresses between the implant and the bone. The aim of this article was to examine the mechanical properties of gradient materials based on carbon fibre-polysulfone composite, and to compare them to the properties of a natural intervertebral disc. Gradient properties were provided by different orientation or volume fraction of carbon fibres in particular layers of composites. The results obtained during in vitro tests displayed a good durability of the gradient materials put under long-term static load. However, the configuration based on a change in the volume fraction of the fibres seems more advantageous than the one based on a change of the fibres' orientation. The materials under study were designed to replace the intervertebral disc. The effect of Young's modulus of the material layers on the stress distribution between the tissue and the implant was analyzed and the biomimetic character of the gradient composites was stated. Unlike gradient materials, the pure polysulfone and the non-gradient composite resulted in the stress concentration in the region of nucleus pulposus, which is highly disadvantageous and does not occur in the stress distribution of natural intervertebral discs. PMID:25306938

  7. Accretion disc origin of the Earth's water.

    PubMed

    Vattuone, Luca; Smerieri, Marco; Savio, Letizia; Asaduzzaman, Abu Md; Muralidharan, Krishna; Drake, Michael J; Rocca, Mario

    2013-07-13

    Earth's water is conventionally believed to be delivered by comets or wet asteroids after the Earth formed. However, their elemental and isotopic properties are inconsistent with those of the Earth. It was thus proposed that water was introduced by adsorption onto grains in the accretion disc prior to planetary growth, with bonding energies so high as to be stable under high-temperature conditions. Here, we show both by laboratory experiments and numerical simulations that water adsorbs dissociatively on the olivine {100} surface at the temperature (approx. 500-1500 K) and water pressure (approx. 10?? bar) expected for the accretion disc, leaving an OH adlayer that is stable at least up to 900 K. This may result in the formation of many Earth oceans, provided that a viable mechanism to produce water from hydroxyl exists. This adsorption process must occur in all disc environments around young stars. The inevitable conclusion is that water should be prevalent on terrestrial planets in the habitable zone around other stars. PMID:23734050

  8. Effects of bone cement on intervertebral disc degeneration.

    PubMed

    Zhao, Hui; Ni, Cai-Fang; Huang, Jian; Zhao, Su-Ming; Gu, Wei-Wei; Jiang, Hao; Chen, Long; Tan, Tian-Si

    2014-04-01

    Percutaneous vertebroplasty (PVP) is popular for the treatment of intractable pain due to vertebral collapse from various lesions, intervertebral disk leakage of cement is a frequent complication. The aim of this study was to determine whether bone cement causes disc degeneration, and to evaluate the degree of intervertebral disc degeneration (IDD) according to the time period following cement injection, and the type and volume of cement injected. Sixteen dogs were randomly divided into two groups that were sacrificed at 12 or 24 weeks following cement injection. Five intervertebral discs in each dog were studied, including one control untreated disc and four discs randomly injected with polymethylmethacrylate (PMMA) or calcium phosphate cement (CPC) in two quantities. Radiographic and magnetic resonance imaging (MRI) studies were performed prior to animal sacrifice. T2-weighted mid-sagittal images of the discs were qualitatively analyzed for evidence of degeneration by calculating the MRI index, and all harvested discs were studied histopathologically. IDD was not evident in control discs. Univariate analysis revealed significant differences in the MRI index and the histological grade of disc degeneration in terms of the time period following cement injection, as well as the type and volume of cement injected. Result indicate that direct contact with PMMA and CPC can lead to IDD. However, IDD induced by PMMA was more severe than that induced by CPC. The extent of IDD was found to correlate with the time period post-cement injection and the volume of cement injected into the disc. PMMA and CPC may lead to intervertebral disc degeneration. Intervertebral disc degeneration induced by PMMA is more serious than that of CPC. The degree of intervertebral disc degeneration is correlative to the time after operation and the doses of bone cement. PMID:24669259

  9. Optical Coherence Tomography Angiography of Optic Disc Perfusion in Glaucoma

    PubMed Central

    Jia, Yali; Wei, Eric; Wang, Xiaogang; Zhang, Xinbo; Morrison, John C.; Parikh, Mansi; Lombardi, Lori H.; Gattey, Devin M.; Armour, Rebecca L.; Edmunds, Beth; Kraus, Martin F.; Fujimoto, James G.; Huang, David

    2014-01-01

    Purpose To compare optic disc perfusion between normal and glaucoma subjects using optical coherence tomography (OCT) angiography and detect optic disc perfusion changes in glaucoma. Design Observational, cross-sectional study. Participants Twenty-four normal subjects and 11 glaucoma patients were included. Methods One eye of each subject was scanned by a high-speed 1050 nm wavelength swept-source OCT instrument. The split-spectrum amplitude-decorrelation angiography algorithm (SSADA) was used to compute three-dimensional optic disc angiography. A disc flow index was computed from four registered scans. Confocal scanning laser ophthalmoscopy (cSLO) was used to measure disc rim area, and stereo photography was used to evaluate cup/disc ratios. Wide field OCT scans over the discs were used to measure retinal nerve fiber layer (NFL) thickness. Main Outcome Measurements Variability was assessed by coefficient of variation (CV). Diagnostic accuracy was assessed by sensitivity and specificity. Comparisons between glaucoma and normal groups were analyzed by Wilcoxon rank-sum test. Correlations between disc flow index, structural assessments, and visual field (VF) parameters were assessed by linear regression. Results In normal discs, a dense microvascular network was visible on OCT angiography. This network was visibly attenuated in glaucoma subjects. The intra-visit repeatability, inter-visit reproducibility, and normal population variability of the optic disc flow index were 1.2%, 4.2%, and 5.0% CV respectively. The disc flow index was reduced by 25% in the glaucoma group (p = 0.003). Sensitivity and specificity were both 100% using an optimized cutoff. The flow index was highly correlated with VF pattern standard deviation (R2 = 0.752, p = 0.001). These correlations were significant even after accounting for age, cup/disc area ratio, NFL, and rim area. Conclusions OCT angiography, generated by the new SSADA algorithm, repeatably measures optic disc perfusion. OCT angiography could be useful in the evaluation of glaucoma and glaucoma progression. PMID:24629312

  10. Control Dewar Secondary Vacuum Container

    SciTech Connect

    Rucinski, R.; /Fermilab

    1993-10-04

    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.

  11. The Application of Fiber-Reinforced Materials in Disc Repair

    PubMed Central

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

    2013-01-01

    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

  12. Accretion disc viscosity: a limit on the anisotropy

    NASA Astrophysics Data System (ADS)

    Nixon, Chris

    2015-07-01

    Observations of warped discs can give insight into the nature of angular momentum transport in accretion discs. Only a few objects are known to show strong periodicity on long time-scales, but when such periodicity is present it is often attributed to precession of the accretion disc. The X-ray binary Hercules X-1/HZ Herculis (Her X-1) is one of the best examples of such periodicity and has been linked to disc precession since it was first observed. By using the current best-fitting models to Her X-1, which invoke precession driven by radiation warping, I place a constraint on the effective viscosities that act in a warped disc. These effective viscosities almost certainly arise due to turbulence induced by the magnetorotational instability. The constraints derived here are in agreement with analytical and numerical investigations into the nature of magnetohydrodynamic disc turbulence, but at odds with some recent global simulations.

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

    NASA Astrophysics Data System (ADS)

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

    1998-04-01

    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 is also critical to high reflectivity and for fabricating clear mark edges. Following these guidelines, excellent 0.4 µm shortest mark length recording characteristics are achieved with original metal azo dye.

  14. Vacuum enhanced cutaneous biopsy instrument

    DOEpatents

    Collins, Joseph (St. Petersburg, FL)

    2000-01-01

    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.

  15. Vacuum flash evaporated polymer composites

    DOEpatents

    Affinito, John D. (Kennewick, WA); Gross, Mark E. (Pasco, WA)

    1997-01-01

    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.

  16. mixing tube vent to vacuum

    E-print Network

    Wilson, Rachel

    mixing tube vent to vacuum main air tube (ID = 6 mm) valve (Cole Palmer 01380-02) a 0 10 20 30 40 after placing an odor into the device vacuum line. (c) Command to the valve, created from binary random

  17. Statistical mechanics of the vacuum

    E-print Network

    Christian Beck

    2012-03-01

    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.

  18. Multipurpose Vacuum Induction Processing System

    NASA Astrophysics Data System (ADS)

    Govindaraju, M.; Kulkarni, Deepak; Balasubramanian, K.

    2012-11-01

    Multipurpose vacuum processing systems are cost effective; occupy less space, multiple functional under one roof and user friendly. A multipurpose vacuum induction system was designed, fabricated and installed in a record time of 6 months time at NFTDC Hyderabad. It was designed to function as a) vacuum induction melting/refining of oxygen free electronic copper/pure metals, b) vacuum induction melting furnace for ferrous materials c) vacuum induction melting for non ferrous materials d) large vacuum heat treatment chamber by resistance heating (by detachable coil and hot zone) e) bottom discharge vacuum induction melting system for non ferrous materials f) Induction heat treatment system and g) directional solidification /investment casting. It contains provision for future capacity addition. The attachments require to manufacture multiple shaped castings and continuous rod casting can be added whenever need arises. Present capacity is decided on the requirement for 10years of development path; presently it has 1.2 ton liquid copper handling capacity. It is equipped with provision for capacity addition up to 2 ton liquid copper handling capacity in future. Provision is made to carry out the capacity addition in easy steps quickly. For easy operational maintenance and troubleshooting, design was made in easily detachable sections. High vacuum system is also is detachable, independent and easily movable which is first of its kind in the country. Detailed design parameters, advantages and development history are presented in this paper.

  19. Breather cloth for vacuum curing

    NASA Technical Reports Server (NTRS)

    Reed, M. W.

    1979-01-01

    Finely-woven nylon cloth that has been treated with Teflon improves vacuum adhesive bonding of coatings to substrates. Cloth is placed over coating; entire assembly, including substrate, coating, and cloth, is placed in plastic vacuum bag for curing. Cloth allows coating to "breathe" when bag is evacuated. Applications include bonding film coatings to solar concentrators and collectors.

  20. Detecting leaks in vacuum bags

    NASA Technical Reports Server (NTRS)

    Carlstrom, E. E.

    1980-01-01

    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.

  1. Vacuum Gas Tungsten Arc Welding

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

    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.

  2. Vacuum flash evaporated polymer composites

    DOEpatents

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

    1997-10-28

    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.

  3. Purifying Aluminum by Vacuum Distillation

    NASA Technical Reports Server (NTRS)

    Du Fresne, E. R.

    1985-01-01

    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.

  4. Audiovisual Bounce-Inducing Effect: Attention Alone Does Not Explain Why the Discs Are Bouncing

    ERIC Educational Resources Information Center

    Grassi, Massimo; Casco, Clara

    2009-01-01

    Two discs moving from opposite points in space, overlapping and stopping at the other disc's starting point, can be seen as either bouncing or streaming through each other. With silent displays, observers report the discs as streaming, whereas if a sound is played when the discs touch each other, observers report the discs as bouncing. The origin…

  5. Molecules in Protoplanetary HAEBE discs as seen with Herschel.

    NASA Astrophysics Data System (ADS)

    Meeus, G.

    2011-05-01

    The discovery of planets around other stars has revealed that planet formation is ubiquitous. However, the mechanisms determining planet formation are not (yet) well-understood. Primordial protoplanetary discs consist 99% out of gas, and only 1% out of dust. With time, those discs are believed to evolve from a flaring geometry into a flat geometry, as the initially small dust grains grow to larger sizes and settle towards the mid-plane. In the mean time, the gas will disperse, until so little is left that giant planets no longer can form. It is thus important to understand the chemical composition of the disc and the influence of the gas heating/cooling processes on the disc structure, and finally how gas gets dispersed as a pieces of the puzzle of planet formation. In this contribution, we study the protoplanetary discs around Herbig Ae/Be stars, young objects of intermediate mass, in the context of gas chemistry. We present Herschel PACS spectroscopic observations for a sample that was obtained within the GASPS (Gas in Protoplanetary Systems) Open Time Key Project, concentrating on the detection and characterisation of emission lines of the molecules H20, CO and CH+ (besides [OI] and [CII]), tracing the disc between 5 and 500 AU. We look for correlations between the observed line fluxes and stellar properties such as effective temperature, Halpha emission, accretion rates and UV flux, as well as the disc properties: degree of flaring, presence and strength of PAH emission and disc mass. We will present a few cases to show how simultaneous modeling (using the thermo-chemical disc code ProDiMo) of the atomic fine structure lines and both Space Telescope and ground-based molecular lines can constrain the disc gas mass, once the disc structure is derived (here with the radiative transfer code MCFost). Finally, we compare our gas line observations with those of young debris disc stars, for which the HAEBE stars are thought to be progenitors.

  6. Glaucomatous-Type Optic Discs in High Myopia

    PubMed Central

    Nagaoka, Natsuko; Jonas, Jost B.; Morohoshi, Kei; Moriyama, Muka; Shimada, Noriaki; Yoshida, Takeshi; Ohno-Matsui, Kyoko

    2015-01-01

    Purpose To assess the prevalence of glaucoma in patients with high myopia defined as myopic refractive error of >-8 diopters or axial length ?26.5 mm. Methods The hospital-based observational study included 172 patients (336 eyes) with a mean age of 61.9±12.3 years and mean axial length of 30.1±2.3 mm (range: 24.7–39.1mm). Glaucomatous-type optic discs were defined by glaucomatous optic disc appearance. Glaucoma was defined by glaucomatous optic disc appearance and glaucomatous Goldmann visual field defects not corresponding with myopic macular changes. Results Larger disc area (mean: 3.18±1.94 mm2) was associated with longer axial length (P<0.001; standardized correlation coefficient: 0.45). Glaucoma was detected in 94 (28%; 95% Confidence intervals: 23%, 33%) eyes. In multivariate analysis, glaucoma prevalence was 3.2 times higher (P<0.001) in megalodiscs (>3.79 mm2) than in normal-sized discs or small discs (<1.51 mm2) after adjusting for older age. Axial length was not significantly (P = 0.38) associated with glaucoma prevalence in that model. Glaucoma prevalence increased by a factor of 1.39 for each increase in optic disc area by one mm2. Again, axial length was not significantly (P = 0.38) associated with glaucoma prevalence when added to this multivariate model. Conclusion Within highly myopic individuals, glaucoma prevalence increased with larger optic disc size beyond a disc area of 3.8 mm2. Highly myopic megalodiscs as compared to normal sized discs or small discs had a 3.2 times higher risk for glaucomatous optic nerve neuropathy. The increased glaucoma prevalence in axial high myopia was primarily associated with axial myopia associated disc enlargement and not with axial elongation itself. PMID:26425846

  7. New Brown Dwarf Discs in Upper Scorpius Observed with WISE

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    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.

  8. Gravitational instability in protostellar discs at low metallicities

    NASA Astrophysics Data System (ADS)

    Tanaka, Kei E. I.; Omukai, Kazuyuki

    2014-04-01

    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.

  9. A search for eclipsing binaries that host discs

    NASA Astrophysics Data System (ADS)

    Meng, Zeyang; Quillen, Alice C.; Bell, Cameron P. M.; Mamajek, Eric E.; Scott, Erin L.; Zhou, Ji-Lin

    2014-07-01

    We search for systems hosting eclipsing discs using a complete sample of eclipsing binaries (EBs); those previously identified in the third phase of the Optical Gravitational Lensing Experiment (OGLE-III). Within a subsample of 2823 high-cadence, high-photometric precision and large eclipsing depth detached EBs previously identified in the Large Magellanic Cloud (LMC), we find that the skewness and kurtosis of the light-curve magnitude distribution within the primary eclipse can distinguish EBs with a complex-shaped eclipse from those without. Two systems with previously identified eclipsing discs (OGLE-LMC-ECL-11893 and OGLE-LMC-ECL-17782) are identified with near zero skewness (|S| < 0.5) and positive kurtosis. No additional eclipsing disc systems were found in the OGLE-III LMC, Small Magellanic Cloud or Galactic Disc EB light curves. We estimate that the fraction of detached early-type LMC EBs (which have a primary with an I-band magnitude brighter than ?19 mag) that exhibit atypical eclipses and so could host a disc is approximately 1/1000. As circumstellar disc lifetimes are short, we expected to primarily find eclipsing discs around young stars. In addition, as there is more room for a disc in a widely separated binary and because a disc close to a luminous star would be above the dust sublimation temperature, we expected to primarily find eclipsing discs in long-period binaries. However, OGLE-LMC-ECL-17782 is a 13.3 d period B star system with a transient and hot (˜6000 K, ˜0.1 au radius) disc and Scott et al. estimate an age of 150 Myr for OGLE-LMC-ECL-11893. Both discs are unexpected in the EB sample and impel explanation.

  10. Cosmology with decaying vacuum energy

    SciTech Connect

    Freese, K.; Adams, F.; Frieman, J.; Mottola, E.

    1987-09-01

    Motivated by recent attempts to solve the cosmological constant problem, we examine the observational consequences of a vacuum energy density which decays in time. For all times later than t approx. 1 sec, the ratio of the vacuum to the total energy density of the universe must be small. Although the vacuum cannot provide the ''missing mass'' required to close the universe today, its presence earlier in the history of the universe could have important consequences. We discuss restrictions on the vacuum energy arising from primordial nucleosynthesis, the microwave and gamma ray background spectra, and galaxy formation. A small vacuum component at the era of nucleosynthesis, 0.01 < rho/sub vac//rho/sup rad/ < 0.1, increase the number of allowed neutino species to N/sup nu/ > 5, but in some cases would severely distort the microwave spectrum. 9 refs., 3 figs.

  11. Spacetime structure and vacuum entanglement

    E-print Network

    Eduardo Martin-Martinez; Alexander R. H. Smith; Daniel R. Terno

    2015-07-09

    We study the role that both vacuum fluctuations and vacuum entanglement of a scalar field play in identifying the spacetime topology, which is not prescribed from first principles---neither in general relativity or quantum gravity. We analyze how the entanglement and observable correlations acquired between two particle detectors are sensitive to the spatial topology of spacetime. We examine the detector's time evolution to all orders in perturbation theory and then study the phenomenon of vacuum entanglement harvesting in Minkowski spacetime and two flat topologically distinct spacetimes constructed from identifications of the Minkowski space. We show that, for instance, if the spatial topology induces a preferred direction, this direction may be inferred from the dependence of correlations between the two detectors on their orientation. We therefore show that vacuum fluctuations and vacuum entanglement harvesting makes it, in principle, possible to distinguish spacetimes with identical local geometry that differ only in their topology.

  12. Nanostructure changes in the intervertebral discs after experimental laser irradiation.

    PubMed

    Byval'tsev, V A; Panasenkov, S Yu; Belykh, E G; Ivanov, N A; Tsyganov, P Yu; Nikiforov, S B; Sorokovikov, V A; Grigor'ev, E G; Kolesnikov, S I

    2015-02-01

    Laser-induced changes in the intervertebral discs were studied by the method of atomic force microscopy. Alteration of the proximal caudal intervertebral discs was modeled in rats: puncture and exposure to diode laser (2, 3, or 5 W) in constant or pulse regimens or only puncture (control). Nanostructure of disc surface was estimated by surface skewness, root mean square and average roughness, and coefficient of kurtosis. Maximum positive effect and signs of regenerative changes in the surface microstructure of the intervertebral discs were found after exposure to laser (2-3 W) in constant or pulse regimens. PMID:25708335

  13. 21 CFR 866.1620 - Antimicrobial susceptibility test disc.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Diagnostic Devices § 866.1620 Antimicrobial susceptibility test disc. (a)...

  14. Angular momentum of disc galaxies with a lognormal density distribution

    NASA Astrophysics Data System (ADS)

    Marr, John H.

    2015-10-01

    By postulating that the majority of the mass and angular momentum of a disc galaxy is confined to the disc with a lognormal surface density distribution, and that galactic discs are substantially, if not fully, self-gravitating, it may be shown that the resultant rotation curves (RCs) display a good overall fit to observational data for a wide range of galaxy types. With this hypothesis, the total angular momentum J, and total energy |E| of 38 disc galaxies was computed and plotted against the derived disc masses, with best fit slopes for J of 1.683 ± 0.018 and |E| of 1.643 ± 0.038, and a universal disc spin parameter ? = 0.423 ± 0.014. Using the disc parameters Vmax and Rmax as surrogates for the virial velocity and radius, a virial mass estimator M_{disc} ? R_{max} V_{max}^2 was generated, with a log-log slope of 1.024 ± 0.014 for the 38 galaxies, and a proportionality constant ?* = 1.47 ± 0.20 × 105 M?kpc- 1 km- 2 s2. This relationship has less scatter than M?(Vrot)?, and may provide an alternative to the Tully-Fisher relation in determining virial disc masses.

  15. MECHANICAL DESIGN CRITERIA FOR INTERVERTEBRAL DISC TISSUE ENGINEERING

    PubMed Central

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

    2009-01-01

    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

  16. Does the stellar disc flattening depend on the galaxy type?

    NASA Astrophysics Data System (ADS)

    Mosenkov, A. V.; Sotnikova, N. Ya.; Reshetnikov, V. P.; Bizyaev, D. V.; Kautsch, S. J.

    2015-08-01

    We analyse the dependence of the stellar disc flatness on the galaxy morphological type using 2D decomposition of galaxies from the reliable subsample of the Edge-on Galaxies in SDSS catalogue. Combining these data with the retrieved models of the edge-on galaxies from the Two Micron All Sky Survey and the Spitzer Survey of Stellar Structure in Galaxies catalogue, we make the following conclusions. The disc relative thickness z0/h in the near- and mid-infrared passbands correlates weakly with morphological type and does not correlate with the bulge-to-total luminosity ratio B/T in all studied bands. Applying a 1D photometric profile analysis overestimates the disc thickness in galaxies with large bulges making an illusion of the relationship between the disc flattening and the ratio B/T. In our sample, the early-type disc galaxies (S0/a) have both flat and `puffed' discs. The early spirals and intermediate-type galaxies have a large scatter of the disc flatness, which can be caused by the presence of a bar: barred galaxies have thicker stellar discs, on average. On the other hand, the late-type spirals are mostly thin galaxies, whereas irregular galaxies have puffed stellar discs.

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

    SciTech Connect

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

    1988-11-01

    Metabolic changes induced by axial vibratory load to the spine were investigated based on water metabolism in normal intervertebral discs of rabbits with or without pentobarbital anesthesia. Tritiated water concentration in the intervertebral discs of unanesthetized rabbits was reduced remarkably by axial vibration for 30 minutes using the vibration machine developed for this study. Repeated vibratory load for 18 and 42 hours duration showed the recovery of /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.

  18. Low-cost ultrahigh areal density optical disc system towards 400 Gbyte/disc

    NASA Astrophysics Data System (ADS)

    Morimoto, Yoshitaka; Kurokawa, Takahiro; Kikukawa, Atsushi; Watanabe, Koichi; Chiba, Zenjiro; Takeshima, Hideharu; Matsuda, Isao; Kojyo, Shinichi; Shimomai, Kenichi; Fujii, Toru

    2015-09-01

    We introduce a new 400 Gbyte disc system, which has twice as much areal density as BDXL™ does, retaining the use of the conventional optical head and disc technology. Our proposal is based on the application of code modulations with enlarged minimum run length (d) and land/groove (L/G) geometry to increase linear recording density and track density by 1.5 and 1.33 times, respectively. Also, saw tooth wobble (STW) was introduced for a multilayered L/G disc system to suppress readout signal fluctuations. Here, we demonstrated that the linear recording density increased to 45.5 Gbyte/layer by applying d = 3 to a commercially available BDXL™. Also, we checked that crosstalk, which is a major concern in an L/G disc with a track pitch of 240 nm, was suppressed to below -30 dB by choosing the proper groove depth. Moreover, the investigation of the effect of track width modulation on the write/read performance demonstrated that an adverse influence can be suppressed by employing STW.

  19. ISASS Policy Statement - Cervical Artificial Disc.

    PubMed

    Coric, Domagoj

    2014-01-01

    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. PMID:25694944

  20. Correlation between Voronoi volumes in disc packings

    E-print Network

    Song-Chuan Zhao; Stacy Sidle; Harry L. Swinney; Matthias Schröter

    2011-12-19

    We measure the two-point correlation of free Voronoi volumes in binary disc packings, where the packing fraction $\\phi_{\\rm avg}$ ranges from 0.8175 to 0.8380. We observe short-ranged correlations over the whole range of $\\phi_{\\rm avg}$ and anti-correlations for $\\phi_{\\rm avg}>0.8277$. The spatial extent of the anti-correlation increases with $\\phi_{\\rm avg}$ while the position of the maximum of the anti-correlation and the extent of the positive correlation shrink with $\\phi_{\\rm avg}$. We conjecture that the onset of anti-correlation corresponds to dilatancy onset in this system.

  1. ISASS Policy Statement – Lumbar Artificial Disc

    PubMed Central

    Garcia, Rolando

    2015-01-01

    Purpose The primary goal of this Policy Statement is to educate patients, physicians, medical providers, reviewers, adjustors, case managers, insurers, and all others involved or affected by insurance coverage decisions regarding lumbar disc replacement surgery. Procedures This Policy Statement was developed by a panel of physicians selected by the Board of Directors of ISASS for their expertise and experience with lumbar TDR. The panel's recommendation was entirely based on the best evidence-based scientific research available regarding the safety and effectiveness of lumbar TDR. PMID:25785243

  2. Vacuum energy and cosmological evolution

    E-print Network

    Joan Sola

    2014-03-03

    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.

  3. Vacuum Brazing of Accelerator Components

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

    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.

  4. Compact vacuum insulation

    DOEpatents

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

    1992-10-27

    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.

  5. Compact vacuum insulation

    DOEpatents

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

    1992-01-01

    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.

  6. NCSX Vacuum Vessel Fabrication

    SciTech Connect

    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

    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.

  7. Vacuum plasma spray coating

    NASA Technical Reports Server (NTRS)

    Holmes, Richard R.; Mckechnie, Timothy N.

    1989-01-01

    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.

  8. 75 FR 54345 - Determination of Regulatory Review Period for Purposes of Patent Extension; BRYAN CERVICAL DISC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-07

    ...marketing the medical device BRYAN CERVICAL DISC SYSTEM. BRYAN CERVICAL DISC SYSTEM is indicated in...intractable radiculopathy and/or myelopathy. Subsequent to this approval...restoration application for BRYAN CERVICAL DISC SYSTEM (U.S....

  9. DISC1 & GSK3? modulate PDE4 activity: functional integration of psychiatric associated signalling pathways 

    E-print Network

    Carlyle, Becky Catherine

    2010-01-01

    Following the discovery of the DISC1 gene in 2000, subsequent research has led to DISC1 becoming one of the most promising candidate genes for psychiatric disorders. Acting as a scaffold protein, DISC1 has a large number ...

  10. Dixdc1 Is a Critical Regulator of DISC1 and Embryonic Cortical Development

    E-print Network

    Singh, Karun K.

    The psychiatric illness risk gene Disrupted in Schizophrenia-1 (DISC1) plays an important role in brain development; however, it is unclear how DISC1 is regulated during cortical development. Here, we report that DISC1 is ...

  11. Dynamic Compression Effects on Intervertebral Disc Mechanics and Biology

    PubMed Central

    Korecki, Casey L.; MacLean, Jeffrey J.; Iatridis, James C.

    2008-01-01

    Study Design A bovine intervertebral disc organ culture model was used to study the effect of dynamic compression magnitude on mechanical behavior and measurement of biosynthesis rate, cell viability, and mRNA expression. Objective The objective of this study was to examine the effect of loading magnitude on intervertebral disc mechanics and biology in an organ culture model. Summary of Background Data The in vivo and cell culture response of intervertebral disc cells to dynamic mechanical loading provides evidence the disc responds in a magnitude dependant manner. However, the ability to link mechanical behavior of the disc with biologic phenomena has been limited. A large animal organ culture system facilitates measurements of tissue mechanics and biologic response parameters on the same sample allowing a broader understanding of disc mechanobiology. Methods Bovine caudal intervertebral discs were placed in organ culture for 6 days and assigned to a static control or 1 of 2 dynamic compression loading protocols (0.2–1 MPa or 0.2–2.5 MPa) at 1 Hz for 1 hour for 5 days. Disc structure was assessed with measurements of dynamic modulus, creep, height loss, water content, and proteoglycan loss to the culture medium. Cellular responses were assessed through changes in cell viability, metabolism, and qRT-PCR analyses. Results Increasing magnitudes of compression increased disc modulus and creep; however, all mechanical parameters recovered each day. In the anulus, significant increases in gene expression for collagen I and a trend of increasing sulfate incorporation were observed. In the nucleus, increasing gene expression for collagen I and MMP3 was observed between magnitudes and between static controls and the lowest magnitude of loading. Conclusion Results support the hypothesis that biologic remodeling precedes damage to the intervertebral disc structure, that compression is a healthy loading condition for the disc, and further support the link between applied loading and biologic remodeling. PMID:18520935

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

    PubMed

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

    2015-12-15

    Objective-To identify characteristics of chondrodystrophoid and nonchondrodystrophoid small-breed dogs with cervical intervertebral disk herniation (IVDH). Design-Retrospective case series. Animals-187 small-breed (? 15 kg [33 lb]) dogs that underwent surgery because of cervical IVDH. Procedures-Medical records were reviewed for information on breed, sex, age, weight, location of affected intervertebral disks, duration and severity of neurologic signs, and recovery time. Results-55 of the 187 (29.4%) dogs were Beagles. The most frequently affected intervertebral disk was C2-3 (81/253 [32.0%]), and this was the more frequently affected intervertebral disk in dogs of several chondrodystrophoid breeds, including Beagles (29/66 [43.9%]), Dachshunds (13/37 [35.1%]), Shih Tzus (16/41 [39.0%]), and Pekingese (3/10 [30.0%]). However, caudal disks (C5-6 or C6-7) were more frequently affected in Yorkshire Terriers (13/24 [54.2%]) and Chihuahuas (9/13 [69%]). Shih Tzus and Yorkshire Terriers were significantly older at the time of surgery (mean ± SD age, 9.6 ± 2.3 years and 9.5 ± 2.5 years, respectively) than were Pomeranians (6.2 ± 2.3 years), and Yorkshire Terriers had a significantly higher number of affected disks (2.0 ± 0.9) than did Dachshunds (1.1 ± 0.3). Mean recovery time was significantly longer in Yorkshire Terriers (36.7 ± 13.0 days) than in Beagles (16.5 ± 17.1 days), Shih Tzus (17.8 ± 14.5 days), or Chihuahuas (12.2 ± 7. 2 days). Conclusions and Clinical Relevance-Results suggested that there may be breed-specific differences in the characteristics of cervical IVDH in small-breed dogs. PMID:26642135

  13. A focussing disc DIRC for PANDA

    NASA Astrophysics Data System (ADS)

    Cowie, E. N.; Britting, A.; Clarkson, A.; Dodokhof, V. KH.; Düren, M.; Dutta, D.; Eyrich, W.; Föhl, K.; Glazer, D. I.; Hayrapetyan, A.; Hoek, M.; Hohler, R.; Kaiser, R.; Keri, T.; Koch, P.; Kröck, B.; Lehmann, A.; Lehmann, D.; Lumsden, S.; Marton, J.; Merle, O.; Montgomery, R.; Peters, K.; Reinicke, S.; Rosner, G.; Roy, B.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Seitz, B.; Sfienti, C.; Suzuki, K.; Uhlig, F.; Vodopianov, A. S.; Watts, D. P.; Yu, W.

    2011-05-01

    The PANDA experiment at the FAIR upgrade to GSI, Darmstadt, aims to study modern hadronic physics with unprecedented precision. Excellent particle identification of both charged and neutral particles is necessary to achieve the physics aims of PANDA. Two DIRC detectors are foreseen for charged particle identification, one in a barrel configuration for the central region, and the second in a disc configuration for the forward endcap. The design of the forward disc DIRC centres around the novel application of passive chromatic dispersion correction elements, allied with focussing optics, to achieve excellent resolution of Chernekov angle. A system of comprehensive prototype development will show the feasibility of the system. Key to the success of the prototype is fully understanding the production, transport and detection of the Cherenkov photons within the detector. Photon yield and its dependence on the polar angle of the detector have been measured. Observed photon yield is also the basis for subsequent studies into the benefit of chromatic dispersion correction elements, focussing and overall detector performance.

  14. Diocotron Modes in Nonneutral Disc Plasmas.

    NASA Astrophysics Data System (ADS)

    Quinn, J. C.; Dubin, D. H. E.

    2006-10-01

    We study the E xB dynamics of a thin disc of charge confined in a cylindrical Penning trap with wall radius Rw. The axial extent (thickness) of the disc is assumed to be negligible. We show that, as in other similar cases, monotonic density profiles are stable to small perturbations. We then consider the specific density profile that is a uniformly charged spheroid of radius R projected onto a plane, because for R Rw it has the special property of rotating without shear. An eigenvalue equation for a density perturbation can be obtained by linearizing the equations of motion and using a Green's function. We find an analytic expression for a special class of eigenmodes, which are the diocotron modes, and the corresponding eigenfrequencies. These expressions are compared to the results of a numerical computation which was done by discretizing the eigenvalue equation. These results are also compared to the 2d limit of the Dubin theory of electrostatic modes in a spheroidal plasma. D.H.E. Dubin, Phys. Rev. Lett. 66, 2076 (1991).

  15. Decimetre dust aggregates in protoplanetary discs

    E-print Network

    Teiser, Jens; 10.1051/0004-6361/200912027

    2011-01-01

    The growth of planetesimals is an essential step in planet formation. Decimetre-size dust agglomerates mark a transition point in this growth process. In laboratory experiments we simulated the formation, evolution, and properties of decimetre-scale dusty bodies in protoplanetary discs. Small sub-mm size dust aggregates consisting of micron-size SiO$_2$ particles randomly interacted with dust targets of varying initial conditions in a continuous sequence of independent collisions. Impact velocities were 7.7 m/s on average and in the range expected for collisions with decimetre bodies in protoplanetary discs. The targets all evolved by forming dust \\emph{crusts} with up to several cm thickness and a unique filling factor of 31% $\\pm$3%. A part of the projectiles sticks directly. In addition, some projectile fragments slowly return to the target by gravity. All initially porous parts of the surface, i.e. built from the slowly returning fragments, are compacted and firmly attached to the underlying dust layers b...

  16. Phase object imaging inside the airy disc

    NASA Astrophysics Data System (ADS)

    Tychinsky, Vladimir P.

    1991-03-01

    The possibility of phase objects superresoluton imaging is theoretically justifieth The measurements with CPM " AIRYSCAN" showed the reality of O structures observations when the Airy disc di ameter i s 0 86 j. . m SUMMARY It has been known that the amount of information contained in the image of any object is mostly determined by the number of points measured i ndependentl y or by spati al resol uti on of the system. From the classic theory of the optical systems it follows that for noncoherent sources the -spatial resolution is limited by the aperture dd 6LX/N. A. ( Rayleigh criterion where X is wave length NA numerical aperture. ) The use of this criterion is equivalent tO the statement that any object inside the Airy disc of radius d that is the difraction image of a point is practical ly unresolved. However at the coherent illumination the intensity distribution in the image plane depends also upon the phase iq (r) of the wave scattered by the object and this is the basis of the Zernike method of phasecontrast microscopy differential interference contrast (DIC) and computer phase microscopy ( CPM ). In theoretical foundation of these methods there was no doubt in the correctness of Rayleigh criterion since the phase information is derived out of intensity distribution and as we know there were no experiments that disproved this

  17. Pressuredriven outflow and magnetocentrifugal wind from a dynamo active disc

    E-print Network

    Brandenburg, Axel

    a numerical model of an accretion disc with mean­field dynamo action that develops pressure­driven collimated is collimated and confined by the azimuthal magnetic field that is produced by the dynamo in the disc and collimating it into a jet in young stellar objects and active galactic nuclei; see K¨onigl & Pudritz (1999

  18. Can giant planets form by gravitational fragmentation of discs?.

    NASA Astrophysics Data System (ADS)

    Stamatellos, D.; Whitworth, A. P.

    2008-03-01

    Context: Gravitational fragmentation has been proposed as a mechanism for the formation of giant planets in close orbits around solar-type stars. However, it is debatable whether this mechanism can function in the inner regions (R? 40 AU) of real discs. Aims: We investigate the thermodynamics of the inner regions of discs and their propensity to fragment. Methods: We use a newly developed method for treating the energy equation and the equation of state, which accounts for radiative transfer effects in SPH simulations of circumstellar discs. The different chemical and internal states of hydrogen and the properties of dust at different densities and temperatures (ice coated dust grains at low temperatures, ice melting, dust sublimation) are all taken into account by the new method. Results: We present radiative hydrodynamic simulations of the inner regions of massive circumstellar discs and examine two cases: (i) a disc irradiated by a cool background radiation field (T_BGR˜ 10 K) and (ii) a disc heated by radiation from its central star (T_BGR˜ 1200~K[R/AU]-1). In neither case does the disc fragment: in the former because it cannot cool fast enough and in the latter because it is not gravitationally unstable. Our results (a) corroborate previous numerical results using different treatments for the hydrodynamics and the radiative transfer, and (b) confirm our own earlier analytic predictions. Conclusions: Disc fragmentation is unlikely to be able to produce giant planets around solar-type stars at radii ?40 AU.

  19. Jet and disc luminosities in tidal disruption events

    NASA Astrophysics Data System (ADS)

    Piran, Tsvi; S?dowski, Aleksander; Tchekhovskoy, Alexander

    2015-10-01

    Tidal disruption events (TDEs) explore the whole range of accretion rates and configurations. A challenging question is what the corresponding light curves of these events are. We explore numerically the disc luminosity and the conditions within the inner region of the disc using a fully general relativistic slim disc model. Those conditions determine the magnitude of the magnetic field that engulfs the black hole and this, in turn, determines the Blandford-Znajek jet power. We estimate this power in two different ways and show that they are self-consistent. We find, as expected earlier from analytic arguments , that neither the disc luminosity nor the jet power follows the accretion rate throughout the disruption event. The disc luminosity varies only logarithmically with the accretion rate at super-Eddington luminosities. The jet power follows initially the accretion rate but remains constant after the transition from super- to sub-Eddington. At lower accretion rates at the end of the magnetically arrested disc (MAD) phase, the disc becomes thin and the jet may stop altogether. These new estimates of the jet power and disc luminosity that do not simply follow the mass fallback rate should be taken into account when searching for TDEs and analysing light curves of TDE candidates. Identification of some of the above-mentioned transitions may enable us to estimate better TDE parameters.

  20. The turbulent viscosity in accretion discs ULF TORKELSSON

    E-print Network

    Brandenburg, Axel

    The turbulent viscosity in accretion discs ULF TORKELSSON Sterrekundig Instituut, Postbus 80000 tur­ bulence. The turbulence is considered to be a likely source for viscosity in accretion discs. Re viscosity. There are however significant quantitative discrepancies between their re­ sults. Estimates

  1. 26 CFR 1.992-1 - Requirements of a DISC.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Domestic International Sales Corporations § 1.992-1 Requirements of a DISC. (a) “DISC... corporation which, for a taxable year— (1) Is duly incorporated and existing under the laws of any State...

  2. DISC1 Ser704Cys impacts thalamic-prefrontal connectivity.

    PubMed

    Liu, Bing; Fan, Lingzhong; Cui, Yue; Zhang, Xiaolong; Hou, Bing; Li, Yonghui; Qin, Wen; Wang, Dawei; Yu, Chunshui; Jiang, Tianzi

    2015-01-01

    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

  3. Laser Discs, Barcodes, and Books--a Great Combination.

    ERIC Educational Resources Information Center

    Peto, Erica

    1996-01-01

    Describes the use of barcodes to link laser discs with books in school libraries. Highlights include use of a barcode reader as a remote control device as well as a scanner, guidelines for making laser disc books, and a sidebar that explains how to make barcodes and describes software. (LRW)

  4. The age of Taurus - environmental effects on disc lifetimes

    E-print Network

    Rees, Jon M; Bell, C P M; Jeffries, R D; Naylor, Tim

    2015-01-01

    Using semi-empirical isochrones, we find the age of the Taurus star-forming region to be 3-4 Myr. Comparing the disc fraction in Taurus to young massive clusters suggests discs survive longer in this low density environment. We also present a method of photometrically de-reddening young stars using $iZJH$ data.

  5. Alumina barrier for vacuum brazing

    NASA Technical Reports Server (NTRS)

    Beuyukian, C. S.

    1980-01-01

    Heating platens of vacuum-brazing press will not stick to workpiece if aluminum oxide "paper" is interposed. Paper does not disintegrate in press, will not contaminate braze alloy, and helps form smoothly contoured, regular fillet at brazed edges.

  6. Vacuum lamination of photovoltaic modules

    NASA Technical Reports Server (NTRS)

    Burger, D. R.

    1982-01-01

    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.

  7. APS storage ring vacuum system

    SciTech Connect

    Niemann, R.C.; Benaroya, R.; Choi, M.; Dortwegt, R.J.; Goeppner, G.A.; Gonczy, J.; Krieger, C.; Howell, J.; Nielsen, R.W.; Roop, B.; Wehrle, R.B.

    1990-01-01

    The Advanced Photon Source synchrotron radiation facility, under construction at the Argonne National Laboratory, incorporates a large ring for the storage of 7 GeV positrons for the generation of photon beams for the facility's experimental program. The Storage Ring's 1104 m circumference is divided into 40 functional sectors. The sectors include vacuum, beam transport, control, acceleration and insertion device components. The vacuum system, which is designed to operate at a pressure of 1 n Torr, consists of 240 connected sections, the majority of which are fabricated from an aluminum alloy extrusion. The sections are equipped with distributed NeG pumping, photon absorbers with lumped pumping, beam position monitors, vacuum diagnostics and valving. The details of the vacuum system design, selected results of the development program and general construction plans are presented. 11 refs., 6 figs., 3 tabs.

  8. Bending instability in galactic discs: advocacy of the linear theory

    NASA Astrophysics Data System (ADS)

    Rodionov, S. A.; Sotnikova, N. Ya.

    2013-09-01

    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.

  9. Analytical Investigation on Squeal Phenomena Generated in Bicycle Disc Brakes

    NASA Astrophysics Data System (ADS)

    Nakae, Takashi; Sueoka, Atsuo; Ryu, Takahiro

    The squeal phenomenon is often generated in bicycle disc brakes. This paper deals analytically with the generation mechanism and the criterion of whether or not the squeal occurs. According to the experimental studies, it has been made clear that the squeal is mainly in-plane vibration in the direction of disc surface with the frequency about 1kHz caused by frictional characteristics with negative slope with respect to the relative velocity. An analytical model of the bicycle disc brake system has been devised to confirm the experimental results, in which a coupled in-plane and out-of-plane vibrating system is composed of the disc, hub, caliper and spokes. The resulting frequency of squeal and the unstable vibration modes of the disc and spokes from the analytical model agreed well with the experimental results.

  10. Cold cathode vacuum gauging system

    DOEpatents

    Denny, Edward C. (Knoxville, TN)

    2004-03-09

    A vacuum gauging system of the cold cathode type is provided for measuring the pressure of a plurality of separate vacuum systems, such as in a gas centrifuge cascade. Each casing is fitted with a gauge tube assembly which communicates with the vacuum system in the centrifuge casing. Each gauge tube contains an anode which may be in the form of a slender rod or wire hoop and a cathode which may be formed by the wall of the gauge tube. The tube is provided with an insulated high voltage connector to the anode which has a terminal for external connection outside the vacuum casing. The tube extends from the casing so that a portable magnet assembly may be inserted about the tube to provide a magnetic field in the area between the anode and cathode necessary for pressure measurements in a cold cathode-type vacuum gauge arrangement. The portable magnetic assembly is provided with a connector which engages the external high voltage terminal for providing power to the anode within in the gauge tube. Measurement is made in the same manner as the prior cold cathode gauges in that the current through the anode to the cathode is measured as an indication of the pressure. By providing the portable magnetic assembly, a considerable savings in cost, installation, and maintenance of vacuum gauges for pressure measurement in a gas centrifuge cascade is realizable.

  11. Technical specification for vacuum systems

    SciTech Connect

    Khaw, J.

    1987-01-01

    The vacuum systems at the Stanford Linear Accelerator Center (SLAC) are primarily of all-metal construction and operate at pressures from 10/sup -5/ to 10/sup -11/ Torr. The primary gas loads during operation result from thermal desorption and beam-induced desorption from the vacuum chamber walls. These desorption rates can be extremely high in the case of hydrocarbons and other contaminants. These specifications place a major emphasis on eliminating contamination sources. The specifications and procedures have been written to insure the cleanliness and vacuum integrity of all SLAC vacuum systems, and to assist personnel involved with SLAC vacuum systems in choosing and designing components that are compatible with existing systems and meet the quality and reliability of SLAC vacuum standards. The specification includes requirements on design, procurement, fabrication, chemical cleaning, clean room practices, welding and brazing, helium leak testing, residual gas analyzer testing, bakeout, venting, and pumpdown. Also appended are specifications regarding acceptable vendors, isopropyl alcohol, bakeable valve cleaning procedure, mechanical engineering safety inspection, notes on synchrotron radiation, and specifications of numerous individual components. (LEW)

  12. Gas Modelling in the Disc of HD 163296

    NASA Technical Reports Server (NTRS)

    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.; Menard, F.; Mendigutia, I.; Duchene, G.; Dent, W. R. F.; Aresu, G.; Meijerink, R.; Spaans, M.

    2011-01-01

    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 approx. 4Myr, with evidence of a circumstellar disc extending out to approx. 540AU. 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 CO-12 3-2, 2-1 and CO-13 J=1-0 line transitions, as well as the H2 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

  13. Magnetised accretion discs in Kerr spacetimes

    NASA Astrophysics Data System (ADS)

    Ranea-Sandoval, Ignacio F.; García, Federico

    2015-01-01

    Context. Observational data from X-ray binary systems provide strong evidence of astronomical objects that are too massive and compact to be explained as neutron or hybrid stars. When these systems are in the thermal (high/soft) state, they emit mainly in the 0.1-5 keV energy range. This emission can be explained by thin accretion discs that formed around compact objects like black holes. The profile of the fluorescent iron line is useful to obtain insight into the nature of the compact object. General relativity does not ensure that a black hole must form after the complete gravitational collapse of very massive stars, and other theoretical models such as naked singularities cannot be discarded. The cosmic censorship conjecture was proposed by Penrose to avoid these possibilities and is yet to be proven. Aims: We study the effect caused by external magnetic fields on the observed thermal spectra and iron line profiles of thin accretion discs formed around Kerr black holes and naked singularities. We aim to provide a tool that can be used to estimate the presence of magnetic fields in the neighbourhood of a compact object and to probe the cosmic censorship conjecture in these particular astrophysical environments. Methods: We developed a numerical scheme able to calculate thermal spectra of magnetised Page-Thorne accretion discs formed around rotating black holes and naked singularities as seen by an arbitrary distant observer. We incorporated two different magnetic field configurations: uniform and dipolar, using a perturbative scheme in the coupling constant between matter and magnetic field strength. Under the same assumptions, we obtained observed synthetic line profiles of the 6.4 keV fluorescent iron line. Results: We show that an external magnetic field produces potentially observable modifications on the thermal energy spectrum and the fluorescent iron line profile. Thermal energy spectra of naked singularities are harder and brighter than those from black holes, and in addition, peak and cut-off energies are affected by the external magnetic field. Moreover, iron line profiles of slowly rotating black holes suffer more changes by a uniform magnetic field, while nearly extremal black holes and naked singularities are more altered in the dipolar case. Based on our calculations, we discard the possibility of modelling the archetypal black-hole candidate in Cygnus X-1 as a naked singularity. Conclusions: Comparison of our models with observational data can be used to probe the cosmic censorship conjecture and to estimate the existence and global geometry of magnetic fields around compact objects by fitting the thermal energy spectra and iron line profiles of X-ray binaries.

  14. An unusual autopsy case of incomplete decapitation of a motorcyclist with herniation of thoracic organs through a helmet-related neck wound.

    PubMed

    Gioia, Sara; Suadoni, Fabio; Carlini, Luigi; Lancia, Massimo; Bacci, Mauro

    2013-12-01

    The authors report an unusual autopsy case of a motorcyclist who wore a full-face type helmet and had incomplete decapitation and herniation of the heart and a portion of the right lung through an extensive lacerate wound on the front of the neck after his motorcycle crashed. The authors identified 2 main offensive dynamics that occurred simultaneously: First, partial decapitation with a extensive gaping wound on the neck caused by the chin strap after a violent angular movement of the head; second, the translocation of the abdominal organs into the thorax and the herniation of the thoracic organs through the neck wound generated by a compressive trauma of the thorax and abdomen. This singular case, like few others in forensic literature, shows the possibility of helmet chin strap-related traumas and highlights the limitations of modern protective helmets. If the postulated mechanism is confirmed despite the massive benefits derived from the compulsory use of protective helmets, the properties of the helmet chin strap would need to be reassessed to improve the protection of the soft tissue and bones in the neck. PMID:24189629

  15. Vacuum Fluctuations Cannot Mimic a Cosmological Constant

    E-print Network

    Robert D. Klauber

    2007-11-05

    When the vacuum fluctuation pressure is calculated directly from fundamental principles of quantum field theory, in the same manner as vacuum fluctuation energy density is commonly calculated, one finds it is not equal to the negative of the vacuum fluctuation energy density. Thus, vacuum fluctuations cannot manifest as a cosmological constant of any order.

  16. High-Speed Recording Performance of Metal Azo Dye Containing Digital Video Disc-Recordable Discs

    NASA Astrophysics Data System (ADS)

    Suzuki, Yuki; Okamoto, Yuuko; Kurose, Yutaka; Maeda, Shuuichi

    1999-03-01

    We have studied the high-speed performance at speeds of 3.5 m/s 14.0 m/s of digital video disc recordable (DVD-R) discs which contain metal azo dyes. Good recording sensitivity and good mark jitter with carrier-to-noise ratio (C/N) > 50 dB at mark lengths of less than 0.40 µm were demonstrated at over 10 m/s due to the high recording responses of the dyes. Furthermore, by introducing the write strategy with pulse trains, the sensitivity difference between mark lengths could be completely eliminated and excellent recording with a jitter value of 8% level has been achieved at 7.0 m/s with a minimum mark length of around 0.4 µm.

  17. Disc-geometry homopolar synchronous machine

    NASA Astrophysics Data System (ADS)

    Evans, P. D.; Eastham, J. F.

    1980-09-01

    Results of an experimental and theoretical investigation of a disc-geometry homopolar synchronous machine with field excitation on the primary side are presented. The unlaminated mild-steel rotor contains no windings and is brushless. The prototype machine produces approximately 7.5 kW of mechanical output at 3000 rev/min, with a product of power factor and efficiency greater than 0.7. The construction of the stator core is unusual and incorporates both laminated and unlaminated portions. The magnetic circuit is also arranged to minimize the axial force between the stator and rotor. A novel rotor design which achieves a reduced quadrature-axis reactance is shown experimentally to be superior to the conventional homopolar rotor.

  18. Multilayer optical disc system using homodyne detection

    NASA Astrophysics Data System (ADS)

    Kurokawa, Takahiro; Ide, Tatsuro; Tanaka, Yukinobu; Watanabe, Koichi

    2014-09-01

    A write/read system using high-productivity multilayer optical discs was developed. The recording medium used in the system consists of planar recording layers and a separated guide layer, and is fabricated by web coating and lamination process. The recording layers in the medium are made of one-photon-absorption material, on which data can be recorded with a normal laser diode. The developed system is capable of focusing and tracking on the medium and amplifying readout signals by using phase-diversity homodyne detection. A highly layer-selective focusing method using homodyne detection was also proposed. This method obtains stable focus-error signals with clearly separated S-shaped curves even when layer spacing is quite narrow, causing large interlayer crosstalk. Writing on the medium and reading with the signal amplification effect of homodyne detection was demonstrated. In addition, the effectiveness of the method was experimentally evaluated.

  19. Optic disc detection using ant colony optimization

    NASA Astrophysics Data System (ADS)

    Dias, Marcy A.; Monteiro, Fernando C.

    2012-09-01

    The retinal fundus images are used in the treatment and diagnosis of several eye diseases, such as diabetic retinopathy and glaucoma. This paper proposes a new method to detect the optic disc (OD) automatically, due to the fact that the knowledge of the OD location is essential to the automatic analysis of retinal images. Ant Colony Optimization (ACO) is an optimization algorithm inspired by the foraging behaviour of some ant species that has been applied in image processing for edge detection. Recently, the ACO was used in fundus images to detect edges, and therefore, to segment the OD and other anatomical retinal structures. We present an algorithm for the detection of OD in the retina which takes advantage of the Gabor wavelet transform, entropy and ACO algorithm. Forty images of the retina from DRIVE database were used to evaluate the performance of our method.

  20. Calculation of the hadronic vacuum polarization disconnected contribution to the muon anomalous magnetic moment

    E-print Network

    T. Blum; P. A. Boyle; T. Izubuchi; L. Jin; A. Jüttner; C. Lehner; K. Maltman; M. Marinkovic; A. Portelli; M. Spraggs

    2015-12-30

    We report the first lattice QCD calculation of the hadronic vacuum polarization disconnected contribution to the muon anomalous magnetic moment at physical pion mass. The calculation uses a refined noise-reduction technique which enabled the control of statistical uncertainties at the desired level with modest computational effort. Measurements were performed on the $48^3 \\times 96$ physical-pion-mass lattice generated by the RBC and UKQCD collaborations. We find $a_\\mu^{\\rm HVP~(LO)~DISC} = -9.6(3.3)(2.3)\\times 10^{-10}$, where the first error is statistical and the second systematic.

  1. Accretion of the Moon from non-canonical discs

    PubMed Central

    Salmon, J.; Canup, R. M

    2014-01-01

    Impacts that leave the Earth–Moon system with a large excess in angular momentum have recently been advocated as a means of generating a protolunar disc with a composition that is nearly identical to that of the Earth's mantle. We here investigate the accretion of the Moon from discs generated by such ‘non-canonical’ impacts, which are typically more compact than discs produced by canonical impacts and have a higher fraction of their mass initially located inside the Roche limit. Our model predicts a similar overall accretional history for both canonical and non-canonical discs, with the Moon forming in three consecutive steps over hundreds of years. However, we find that, to yield a lunar-mass Moon, the more compact non-canonical discs must initially be more massive than implied by prior estimates, and only a few of the discs produced by impact simulations to date appear to meet this condition. Non-canonical impacts require that capture of the Moon into the evection resonance with the Sun reduced the Earth–Moon angular momentum by a factor of 2 or more. We find that the Moon's semi-major axis at the end of its accretion is approximately 7R?, which is comparable to the location of the evection resonance for a post-impact Earth with a 2.5?h rotation period in the absence of a disc. Thus, the dynamics of the Moon's assembly may directly affect its ability to be captured into the resonance. PMID:25114307

  2. Disc fragmentation rarely forms planetary-mass objects

    NASA Astrophysics Data System (ADS)

    Rice, Ken; Lopez, Eric; Forgan, Duncan; Biller, Beth

    2015-12-01

    It is now reasonably clear that disc fragmentation can only operate in the outer parts of protostellar discs (r > 50 au). It is also expected that any object that forms via disc fragmentation will have an initial mass greater than that of Jupiter. However, whether or not such a process actually operates, or can play a significant role in the formation of planetary-mass objects, is still unclear. We do have a few examples of directly imaged objects that may have formed in this way, but we have yet to constrain how often disc fragmentation may actually form such objects. What we want to consider here is whether or not we can constrain the likely population of planetary-mass objects formed via disc fragmentation by considering how a population of objects at large radii (a > 50) au - if they do exist - would evolve under perturbations from more distant stellar companions. We find that there is a specific region of parameter space to which such objects would be scattered and show that the known exoplanets in that region have properties more consistent with that of the bulk exoplanet population, than with having been formed via disc fragmentation at large radii. Along with the scarcity of directly imaged objects at large radii, our results provide a similar, but independent, constraint on the frequency of objects formed via disc fragmentation.

  3. On the vertical-shear instability in astrophysical discs

    NASA Astrophysics Data System (ADS)

    Barker, A. J.; Latter, H. N.

    2015-06-01

    We explore the linear stability of astrophysical discs exhibiting vertical shear, which arises when there is a radial variation in the temperature or entropy. Such discs are subject to a `vertical-shear instability', which recent non-linear simulations have shown to drive hydrodynamic activity in the MRI-stable regions of protoplanetary discs. We first revisit locally isothermal discs using the quasi-global reduced model derived by Nelson et al. This analysis is then extended to global axisymmetric perturbations in a cylindrical domain. We also derive and study a reduced model describing discs with power-law radial entropy profiles (`locally polytropic discs'), which are somewhat more realistic in that they possess physical (as opposed to numerical) surfaces. The fastest growing modes have very short wavelengths and are localized at the disc surfaces (if present), where the vertical shear is maximal. An additional class of modestly growing vertically global body modes is excited, corresponding to destabilized classical inertial waves (`r modes'). We discuss the properties of both types of modes, and stress that those that grow fastest occur on the shortest available length-scales (determined either by the numerical grid or the physical viscous length). This ill-posedness makes simulations of the instability difficult to interpret. We end with some brief speculation on the non-linear saturation and resulting angular momentum transport.

  4. Does the stellar disc flattening depend on the galaxy type?

    E-print Network

    Mosenkov, A V; Reshetnikov, V P; Bizyaev, D V; Kautsch, S J

    2015-01-01

    We analyze the dependence of the stellar disc flatness on the galaxy morphological type using 2D decomposition of galaxies from the reliable subsample of the Edge-on Galaxies in SDSS (EGIS) catalogue. Combining these data with the retrieved models of the edge-on galaxies from the Two Micron All Sky Survey (2MASS) and the Spitzer Survey of Stellar Structure in Galaxies (S$^4$G) catalogue, we make the following conclusions: (1) The disc relative thickness $z_0/h$ in the near- and mid-infrared passbands correlates weakly with morphological type and does not correlate with the bulge-to-total luminosity ratio $B/T$ in all studied bands. (2) Applying an 1D photometric profile analysis overestimates the disc thickness in galaxies with large bulges making an illusion of the relationship between the disc flattening and the ratio $B/T$. (3) In our sample the early-type disc galaxies (S0/a) have both flat and "puffed" discs. The early spirals and intermediate-type galaxies have a large scatter of the disc flatness, whic...

  5. Accretion of the Moon from non-canonical discs.

    PubMed

    Salmon, J; Canup, R M

    2014-09-13

    Impacts that leave the Earth-Moon system with a large excess in angular momentum have recently been advocated as a means of generating a protolunar disc with a composition that is nearly identical to that of the Earth's mantle. We here investigate the accretion of the Moon from discs generated by such 'non-canonical' impacts, which are typically more compact than discs produced by canonical impacts and have a higher fraction of their mass initially located inside the Roche limit. Our model predicts a similar overall accretional history for both canonical and non-canonical discs, with the Moon forming in three consecutive steps over hundreds of years. However, we find that, to yield a lunar-mass Moon, the more compact non-canonical discs must initially be more massive than implied by prior estimates, and only a few of the discs produced by impact simulations to date appear to meet this condition. Non-canonical impacts require that capture of the Moon into the evection resonance with the Sun reduced the Earth-Moon angular momentum by a factor of 2 or more. We find that the Moon's semi-major axis at the end of its accretion is approximately 7R?, which is comparable to the location of the evection resonance for a post-impact Earth with a 2.5?h rotation period in the absence of a disc. Thus, the dynamics of the Moon's assembly may directly affect its ability to be captured into the resonance. PMID:25114307

  6. Measurement of partial pressures in vacuum technology and vacuum physics

    NASA Technical Reports Server (NTRS)

    Huber, W. K.

    1986-01-01

    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.

  7. Finite Time Vacuum Survival Amplitude and Vacuum Energy Decay

    E-print Network

    Enrique Álvarez; Roberto Vidal

    2011-07-15

    The problem of the vacuum energy decay is studied for both signs of the cosmological constant, through the analysis of the vacuum survival amplitude, defined in terms of the {\\em conformal time}, $z$, by ${\\mathcal A}(z,z^\\prime)\\equiv $. Transition amplitudes are computed for finite time-span, $Z\\equiv z^\\prime-z$, and their {\\em late time} behavior (directly related to the putative decay width of the state) as well as the transients are discussed up to first order in the coupling constant, $\\lambda$.

  8. RFQ Vacuum brazing at CERN

    E-print Network

    Mathot, S

    2008-01-01

    The aim of this paper is to describe the vacuum brazing procedure used at CERN for the brazing of Radio Frequency Quadrupole (RFQ). The RFQ is made of high precision machined OFE copper pieces assembled together. Vacuum brazing is one of the most promising techniques used to join the individual components leading to vacuum tightness and high precision alignment. The RFQ modules brazed at CERN are made of four 100 or 120 cm long vanes (two major and two minor vanes). Our brazing procedure consists of two steps. The first step involves the brazing of the four vanes in a horizontal position. The second step consists of brazing the vacuum stainless steel flanges to the copper structure in a vertical position. The paper describes the problems encountered with the alignment and the vacuum tightness. The difficulties related to the stress relaxation of the machined copper pieces during the brazing heat treatment are discussed. In addition, the solutions developed to improve the alignment of the brazed RFQâ??s are...

  9. Vacuum as a hyperbolic metamaterial

    E-print Network

    Igor I. Smolyaninov

    2011-08-10

    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.

  10. Reduce costs with vacuum excavation

    SciTech Connect

    Vitale, S.A.

    1983-09-01

    Although vacuum excavation equipment and methods are in their infancy, this developing technology offers tremendous promise for the future. The author explains Brooklyn Union Gas Co.'s experience with five vacuum trucks and the procedures that are used. In recent years, the higher cost of natural gas has increased the need for gas utilities to reduce their operating expenses. One way, which has been successful at Brooklyn Union Gas, is the use of vacuum excavation. Although vacuum excavation equipment and techniques are in their infancy, this developing technology offers substantial savings today and tremendous promise for the future. Brooklyn Union started its vacuum digging program by locating keyhole cutoffs--small surface openings ranging from 1 ft by 1 ft to 1 1/2 ft by 1 1/2 ft (0.3 m to 0.45 m square). It is no easy task to accurately locate a service that was installed 60 years ago. Reading the street indications, locating an existing curb valve or repair opening, gaining access to the building, making a physical lineup, and using an M-scope, plus any other tools available, have produced a high success rate.

  11. Size distributions of dust in circumstellar debris discs

    NASA Astrophysics Data System (ADS)

    Krivov, A. V.; Mann, I.; Krivova, N. A.

    2000-10-01

    The size distribution of particles in a dust disc is determined by, and holds the key to, sources, sinks and dynamics of grains. Here we derive the size distribution in circumstellar debris discs, exemplified by the disc of begin {equation}ta Pictoris, by modelling the dynamical evolution of the circumstellar dust, dominated by collisions. The whole disc is considered as consisting of two dust populations: larger grains moving in bound orbits (alpha -meteoroids) and smaller ones blown away by radiation pressure (begin {equation}ta-meteoroids). Although begin {equation}ta-meteoroids leave the disc in hyperbolic trajectories, they are continuously replenished by collisions, so that at any time the disc contains a substantial population of small particles. As a consequence, the fragmentation of alpha -meteoroids not only by mutual collisions, but also by impacts of begin {equation}ta-meteoroids becomes significant. This flattens the distribution of alpha -meteoroids in the size regime adjacent to the blow-out limit and shifts the cross section-dominating sizes from a few micrometres to ga 10 mum . The overall distribution shows essentially three different slopes: steeper ones for both begin {equation}ta-meteoroids and large alpha -meteoroids and a gentler one for alpha -meteoroids with sizes just above the blow-out limit. This resembles the size distribution of interplanetary dust particles in the Solar system which, however, is shaped by different mechanisms. The basic features of the modelled size distribution (the presence of a substantial population of small hyperbolic particles in the disc, the dominance of grains ~ 10 mum in size) well agree with the observational data available. Although particular calculations were made for the begin {equation}ta Pic disc, our basic qualitative conclusions directly apply to the debris discs around other Vega-type stars with low gas contents and similar or somewhat lower optical depths.

  12. Gap formation and stability in non-isothermal protoplanetary discs

    NASA Astrophysics Data System (ADS)

    Les, Robert; Lin, Min-Kai

    2015-06-01

    Several observations of transition discs show lopsided dust distributions. A potential explanation is the formation of a large-scale vortex acting as a dust-trap at the edge of a gap opened by a giant planet. Numerical models of gap-edge vortices have so far employed locally isothermal discs in which the temperature profile is held fixed, but the theory of this vortex-forming or `Rossby wave' instability was originally developed for adiabatic discs. We generalize the study of planetary gap stability to non-isothermal discs using customized numerical simulations of disc-planet systems where the planet opens an unstable gap. We include in the energy equation a simple cooling function with cooling time-scale t_c=? ? _k^{-1}, where ?k is the Keplerian frequency, and examine the effect of ? on the stability of gap edges and vortex lifetimes. We find increasing ? lowers the growth rate of non-axisymmetric perturbations, and the dominant azimuthal wavenumber m decreases. We find a quasi-steady state consisting of one large-scale, overdense vortex circulating the outer gap edge, typically lasting O(103) orbits. We find vortex lifetimes generally increase with the cooling time-scale tc up to an optimal value of tc ˜ 10 orbits, beyond which vortex lifetimes decrease. This non-monotonic dependence is qualitatively consistent with recent studies using strictly isothermal discs that vary the disc aspect ratio. The lifetime and observability of gap-edge vortices in protoplanetary discs is therefore dependent on disc thermodynamics.

  13. Local and global dynamics of warped astrophysical discs

    NASA Astrophysics Data System (ADS)

    Ogilvie, Gordon I.; Latter, Henrik N.

    2013-08-01

    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 and 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 hydrodynamic states in the local model are horizontally uniform laminar flows that oscillate at the orbital frequency. These correspond to the non-linear solutions for warped discs found in previous work by Ogilvie, and we present an alternative derivation and generalization of that theory. In a companion paper, we show that these laminar flows are often linearly unstable, especially if the disc is nearly Keplerian and of low viscosity. The local model can be used in future work to determine the non-linear outcome of the hydrodynamic instability of warped discs, and its interaction with others such as the magnetorotational instability.

  14. Cervical Disc Injury—Symptoms and Conservative Treatment

    PubMed Central

    Gorham, F. W.

    1964-01-01

    Primary traumatic cervical disc disease and chronic disc disease associated with spondylitis aggravated by injury causes referred pain to the head, face, neck, arms, shoulders and chest, and even in the low back. Such pain may be reproduced by the injection of contrast medium for cervical discography. Dorsal nerve root pain is rare. Clear-cut disc derangement or annular incompetence may be demonstrated by discography at levels which reproduce symptoms. The pain pattern at each level is not consistent. Conservative treatment, involving primarily the use of a cervical extension collar, results in substantial improvement in 75 per cent of cases. PMID:14229745

  15. Simple solutions of multilayered discs subjected to biaxial moment loading.

    SciTech Connect

    Hsueh, Chun-Hway; Kelly, J R

    2009-01-01

    The purpose of this study was to derive a simple closed-form solution for the stress distribution through the thickness of multilayered discs subjected to biaxial moment loading, such that it can be used readily to evaluate the biaxial strength of multilayered dental ceramics using biaxial flexure tests. Methods A simple analytical model was developed to derive the stress distribution through the thickness of multilayered discs subjected to biaxial moment loading. The accuracy of the solution was verified by comparing with previous rigorous analytical solutions and finite element results. The results obtained from Roark's formulas for bilayered discs were also included for comparison.

  16. Hot Jupiters and Central Cavities of Protoplanetary Discs

    E-print Network

    Szymon Starczewski; Artur J. Gawryszczak; Richard Wunsch; Michal Rozyczka

    2007-11-12

    We investigate numerically the orbital evolution of massive extrasolar planets within central cavities of their parent protoplanetary discs. Assuming that they arrive at the inner edge of the disc due to type II migration, we show that they spiral further in. We find that in magnetospheric cavities more massive planets stop migrating at a larger distance from the edge of the disc. This effect may qualitatively explain the correlation between masses and orbital periods found for massive planets with P shorter than 5 days.

  17. Constraining the thick disc formation scenario of the Milky Way

    NASA Astrophysics Data System (ADS)

    Robin, A. C.; Reylé, C.; Fliri, J.; Czekaj, M.; Robert, C. P.; Martins, A. M. M.

    2014-09-01

    Aims: More than 30 years after its discovery, the thick disc of the Milky Way is not fully explored. We examine the shape of the thick disc in order to gain insight into the process of its formation. Methods: The shape of the thick disc is studied in detail using photometric data at high and intermediate latitudes from SDSS and 2MASS surveys. We adopted the population synthesis approach using an approximate Bayesian computation - Markov chain Monte Carlo (ABC-MCMC) method to determine the potential degeneracies in the parameters that can be caused by the mixing with the halo and the thin disc. We characterised the thick-disc shape, scale height, scale length, local density, and flare, and we investigated the extent of the thick-disc formation period by simulating several formation episodes. Results: We find that the vertical variation in density is not exponential, but much closer to a hyperbolic secant squared. Assuming a single formation epoch, the thick disc is better fitted with a sech2 scale height of 470 pc and a scale length of 2.3 kpc. However, if one simulates two successive formation episodes, which mimicks an extended formation period, the older episode has a higher scale height and a longer scale length than the younger episode, which indicates a contraction during the collapse phase. The scale height decreases from 800 pc to 340 pc, the scale length from 3.2 kpc to 2 kpc. The likelihood is much higher when the thick disc formation extends over a longer period. We also show that star formation increases from the old episode to the young and that there is no flare in the outskirt of the thick disc during the main episode. We compare our results with formation scenarios of the thick disc. During the fitting process, the halo parameters are determined as well. If a power-law density is assumed, it has an exponent of 3.3 and an axis ratio of 0.7. Alternatively, a Hernquist shape would have an exponent of 2.76, an axis ratio of 0.77, and a core radius of 2.1 kpc. The constraint on the halo shows that a transition between an inner and outer halo, if it exists, cannot be at a distance shorter than about 30 kpc, which is the limit of our investigation using turnoff halo stars. Finally, we show that extrapolating the thick disc towards the bulge region explains well the stellar populations observed there that there is no longer need to invoke a classical bulge. Conclusions: The facts that the thick-disc episode lasted for several billion years, that a contraction is observed during the collapse phase, and that the main thick disc has a constant scale height with no flare argue against the formation of the thick disc through radial migration. The most probable scenario for the thick disc is that it formed while the Galaxy was gravitationally collapsing from well-mixed gas-rich giant clumps that were sustained by high turbulence, which prevented a thin disc from forming for a time, as proposed previously. This scenario explains well the observations in the thick-disc region and in the bulge region. Figures 8-11 and Appendix A are available in electronic form at http://www.aanda.org

  18. Microscale Digital Vacuum Electronic Gates

    NASA Technical Reports Server (NTRS)

    Manohara, Harish (Inventor); Mojarradi, Mohammed M. (Inventor)

    2014-01-01

    Systems and methods in accordance with embodiments of the invention implement microscale digital vacuum electronic gates. In one embodiment, a microscale digital vacuum electronic gate includes: a microscale field emitter that can emit electrons and that is a microscale cathode; and a microscale anode; where the microscale field emitter and the microscale anode are disposed within at least a partial vacuum; where the microscale field emitter and the microscale anode are separated by a gap; and where the potential difference between the microscale field emitter and the microscale anode is controllable such that the flow of electrons between the microscale field emitter and the microscale anode is thereby controllable; where when the microscale anode receives a flow of electrons, a first logic state is defined; and where when the microscale anode does not receive a flow of electrons, a second logic state is defined.

  19. Gravity-Induced Vacuum Dominance

    SciTech Connect

    Lima, William C. C.; Vanzella, Daniel A. T.

    2010-04-23

    It has been widely believed that, except in very extreme situations, the influence of gravity on quantum fields should amount to just small, subdominant contributions. This view seemed to be endorsed by the seminal results obtained over the last decades in the context of renormalization of quantum fields in curved spacetimes. Here, however, we argue that this belief is false by showing that there exist well-behaved spacetime evolutions where the vacuum energy density of free quantum fields is forced, by the very same background spacetime, to become dominant over any classical energy-density component. By estimating the time scale for the vacuum energy density to become dominant, and therefore for backreaction on the background spacetime to become important, we argue that this (infrared) vacuum dominance may bear unexpected astrophysical and cosmological implications.

  20. Impedances of Laminated Vacuum Chambers

    SciTech Connect

    Burov, A.; Lebedev, V.; /Fermilab

    2011-06-22

    First publications on impedance of laminated vacuum chambers are related to early 70s: those are of S. C. Snowdon [1] and of A. G. Ruggiero [2]; fifteen years later, a revision paper of R. Gluckstern appeared [3]. All the publications were presented as Fermilab preprints, and there is no surprise in that: the Fermilab Booster has its laminated magnets open to the beam. Being in a reasonable mutual agreement, these publications were all devoted to the longitudinal impedance of round vacuum chambers. The transverse impedance and the flat geometry case were addressed in more recent paper of K. Y. Ng [4]. The latest calculations of A. Macridin et al. [5] revealed some disagreement with Ref. [4]; this fact stimulated us to get our own results on that matter. Longitudinal and transverse impendances are derived for round and flat laminated vacuum chambers. Results of this paper agree with Ref. [5].