545 research outputs found
Improvement of the process for electrochemical impregnation of nickel hydroxide electrodes
Nickel hydroxide electrodes containing 11g/dsqm hydroxide, with capacities of 3.6 to 3.8 Ah/dsqm were prepared at 353 K by electrochemical impregnation. The reproducibility of the results is obtained by readjusting the pH before each preparation. The control of each electrode is done during two cycles of charge and discharge following the manufacture by a potential relaxation method
New Physics with three-photon events at LEP
The effect of the most general \z3gt vertex in the reaction e^+e^- \ra
3\gamma is studied with a particular attention to LEP searches. We give exact
analytical expressions including realistic cuts for the signal and present a
detailed analysis based on a Monte Carlo that includes the effect of the
irreducible QED cross section. As special applications we discuss the
effect of heavy scalars, fermions and gauge bosons and comment on the
``monopole" connection.Comment: No changes made from previous version, 34 pages, LateX, uses epsf, 11
.eps figs., full paper (including figs) is also available via WWW at
http://lapphp0.in2p3.fr/preplapp/psth/lastee3g.ps.gz or via anonymous ftp at
ftp:///lapphp0.in2p3.fr/pub/preprints-theorie/ftpee3g.u
GRACE/SUSY Automatic Generation of Tree Amplitudes in the Minimal Supersymmetric Standard Model
GRACE/SUSY is a program package for generating the tree-level amplitude and
evaluating the corresponding cross section of processes of the minimal
supersymmetric extension of the standard model (MSSM). The Higgs potential
adopted in the system, however, is assumed to have a more general form
indicated by the two-Higgs-doublet model. This system is an extension of GRACE
for the standard model(SM) of the electroweak and strong interactions. For a
given MSSM process the Feynman graphs and amplitudes at tree-level are
automatically created. The Monte-Carlo phase space integration by means of
BASES gives the total and differential cross sections. When combined with
SPRING, an event generator, the program package provides us with the simulation
of the SUSY particle productions.Comment: 39 page, 1 figur
t(4;12)(q11-q21;p13)
Review on t(4;12)(q11-q21;p13), with data on clinics, and the genes involved
3D micro-computed tomography of trabecular and cortical bone architecture with application to a rat model of immobilisation osteoporosis
Bone mass and microarchitecture are the main determinants of bone strength. Three-dimensional micro-computed tomogrpahy has the potential to examine complete bones of small laboratory animals with very high resolution in a non-invasive way. In the presented work, the proximal part of the tibiae of hindlimb unloaded and control rats were measured with 3D MicroCT, and the secondary spongiosa of the scanned region was evaluated using direct evaluation techniques that do not require model assumptions. For determination of the complete bone status, the cortex of the tibiae was evaluated and characterised by its thickness. It is shown that with the proposed anatomically conforming volume of interest (VOI), up to an eight-fold volume increase can be evaluated compared to cubic or spherical VOIs. A pronounced trabecular bone loss of â50% is seen after 23 days of tail suspension. With the new evaluation techniques, it is shown that most of this bone loss is caused by the thinning of trabeculae, and to a lesser extent by a decrease in their number. What changes most radically is the structure type: the remaining bone is more rod-like than the control group's bone. Cortical bone decreases less than trabecular bone, with only â18% after 23 day
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Cervical Deformity Patients Have Baseline Swallowing Dysfunction but Surgery Does Not Increase Dysphagia at 3 Months: Results From a Prospective Cohort Study.
Study designProspective cohort study.ObjectivesMost studies of dysphagia in the cervical spine have focused on a degenerative patient population; the rate of dysphagia following surgery for cervical deformity (CD) is unknown. This study aims to investigate if surgery for cervical deformity results in postoperative dysphagia.MethodsPatients with CD undergoing surgery from 2013 to 2015 were prospectively enrolled to evaluate dysphagia. Demographic, operative, and radiographic variables were analyzed. The Quality of Life in Swallowing Disorders (SWAL-QoL) was used to measure dysphagia. Paired t test, independent t tests, and bivariate Pearson correlations were performed.ResultsA total of 88 CD patients, aged 61.52 ± 10.52 years, were enrolled. All patients (100%) had 3-month SWAL-QoL for analysis. The baseline preoperative SWAL-QoL was 78.35. This is roughly the same level of dysphagia as an anterior cervical discectomy patient that is 3 weeks removed from surgery. Increasing body mass index (BMI) was correlated with decreased SWAL-QoL score (r = -0.30, P = .001). Age, gender, smoking, and Charlson Comorbidity Index (CCI) showed no significant correlations with preoperative SWAL-QoL. Patients with prior cervical surgery had a lower preoperative SWAL-QoL (P = .04). While 11 patients had acute postoperative dysphagia, CD surgery did not result in lower SWAL-QoL at 3 months (77.26 vs 78.35, P = .53). Surgical variables, including estimated blood loss (EBL), anterior or posterior fusion levels, steroid use, preoperative traction, staged surgery, surgical approach, anterior corpectomy, posterior osteotomy, and UIV (upper instrumented vertebrae) location, showed no impact on postoperative SWAL-QoL. Correction of cervical kyphosis was not correlated to 3-month SWAL-QoL scores or the change in SWAL-QoL scores.ConclusionsWhile patients undergoing surgery for cervical deformity had swallowing dysfunction at baseline, we did not observe a significant decline in SWAL-QoL scores at 3 months. Patients with prior cervical surgery and higher BMI had a lower baseline SWAL-QoL. There were no surgical or radiographic variables correlated to a change in SWAL-QOL score
Is There a Patient Profile That Characterizes a Patient With Adult Spinal Deformity as a Candidate for Minimally Invasive Surgery?
Study designRetrospective review.ObjectivesThe goal of this study was to evaluate the baseline characteristics of patients chosen to undergo traditional open versus minimally invasive surgery (MIS) for adult spinal deformity (ASD).MethodsA multicenter review of 2 databases including ASD patients treated with surgery. Inclusion criteria were age >45 years, Cobb angle minimum of 20°, and minimum 2-year follow-up. Preoperative radiographic parameters and disability outcome measures were reviewed.ResultsA total of 350 patients were identified: 173 OPEN patients and 177 MIS. OPEN patients were significantly younger than MIS patients (61.5 years vs 63.74 years, P = .013). The OPEN group had significantly more females (87% vs 76%, P = .006), but both groups had similar body mass index. Preoperative lumbar Cobb was significantly higher for the OPEN group (34.2°) than for the MIS group (26.0°, P < .001). The mean preoperative Oswestry Disability Index was significantly higher in the MIS group (44.8 in OPEN patients and 49.8 in MIS patients, P < .011). The preoperative Numerical Rating Scale value for back pain was 7.2 in the OPEN group and 6.8 in the MIS group preoperatively, P = .100.ConclusionsPatients chosen for MIS for ASD are slightly older and have smaller coronal deformities than those chosen for open techniques, but they did not have a substantially lesser degree of sagittal malalignment. MIS surgery was most frequently utilized for patients with an sagittal vertical axis under 6âcm and a baseline pelvic incidence and lumbar lordosis mismatch under 30°
The posterior use of BMP-2 in cervical deformity surgery does not result in increased early complications: A prospective multicenter study
Study designProspective cohort study.ObjectivesTo describe the rate of short-term complications following the posterior use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in cervical deformity (CD) surgery.MethodsCD patients from 2013 to 2015 were enrolled in a prospective, multicenter database. Patients were divided into those receiving rhBMP-2 (BMP) and no rhBMP-2 (NOBMP). The relationship between BMP use, demographic variables surgical variables, radiographic parameters and complications was evaluated.ResultsA total of 100 patients (47 BMP, 53 NOBMP) were included. Follow-up time averaged 7.6 months (range 3-12 months). An average of 13.6mg of BMP was used per person with 1.49 mg per level. Compared with the NOBMP group, patients in the BMP group were older (P = .03). BMP was more commonly used in patients that and had longer prior fusions (6.0 vs 2.5, P < .01). There were no differences between groups with regards to a history of surgery, Charlson Comorbidity Index, estimated blood loss, operation time, fusion levels, and surgical approach. The maintenance of radiographic parameters at 6-month follow-up was similar. There were no differences in terms of total complication incidence, total complications per person, major complications per person or any specific complication. Linear regression and Pearson correlation analysis did not reveal any strong r2 values (r2 = 0.09, 0.08, 0.06) between the use of BMP and complications (major or operative).ConclusionsBMP use was not directly associated with an increased incidence of early complications in this prospective cohort of operative adult CD patients. Its use was associated with increased number of levels instrumented and fused
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Cervical, Thoracic, and Spinopelvic Compensation After Proximal Junctional Kyphosis (PJK): Does Location of PJK Matter?
Study Design:Retrospective case series. Objective:Compensatory changes above a proximal junctional kyphosis (PJK) have not been defined. Understanding these mechanisms may help determine optimal level selection when performing revision for PJK. This study investigates how varying PJK location changes proximal spinal alignment. Methods:Patients were grouped by upper instrumented vertebrae (UIV): lower thoracic (LT; T8-L1) or upper thoracic (UT; T1-7). Alignment parameters were compared. Correlation analysis was performed between PJK magnitude and global/cervical alignment. Results:A total of 369 patients were included; mean age of 63 years, body mass index 28, and 81% female, LT (n = 193) versus UT (n = 176). The rate of radiographic PJK was 49%, higher in the LT group (55% vs 42%, P = .01). The UT group displayed significant differences in all cervical radiographic parameters (P < .05) between PJK versus non-PJK patients, while the LT group displayed significant differences in T1S and C2-T3 sagittal vertical axis (SVA) (CTS). In comparing UT versus LT patients, UT had more posterior global alignment (smaller TPA [T1 pelvic angle], SVA, and larger PT [pelvic tilt]) and larger anterior cervical alignment (greater cSVA [cervical SVA], T1S-CL [T1 slope-cervical lordosis] mismatch, CTS) compared to LT. Correlation analysis of PJK magnitude and location demonstrated a correlation with increases in CL, T1S, and CTS in the UT group. In the LT group, PT increased with PJK angle (r = 0.17) and no significant correlations were noted to SVA, cSVA, or T1S-CL. Conclusions:PJK location influences compensation mechanisms of the cervical and thoracic spine. LT PJK results in increased PT and CL with decreased CTS. UT PJK increases CL to counter increases in T1S with continued T1S-CL mismatch and elevated cSVA
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Clinically Significant Thromboembolic Disease in Adult Spinal Deformity Surgery: Incidence and Risk Factors in 737 Patients.
Study Design:Retrospective cohort study. Objectives:Describe the rate and risk factors for venous thromboembolic events (VTEs; defined as deep venous thrombosis [DVT] and/or pulmonary embolism [PE]) in adult spinal deformity (ASD) surgery. Methods:ASD patients with VTE were identified in a prospective, multicenter database. Complications, revision, and mortality rate were examined. Patient demographics, operative details, and radiographic and clinical outcomes were compared with a non-VTE group. Multivariate binary regression model was used to identify predictors of VTE. Results:A total of 737 patients were identified, 32 (4.3%) had VTE (DVT = 14; PE = 18). At baseline, VTE patients were less likely to be employed in jobs requiring physical labor (59.4% vs 79.7%, P < .01) and more likely to have osteoporosis (29% vs 15.1%, P = .037) and liver disease (6.5% vs 1.4%, P = .027). Patients with VTE had a larger preoperative sagittal vertical axis (SVA; 93âmm vs 55âmm, P < .01) and underwent larger SVA corrections. VTE was associated with a combined anterior/posterior approach (45% vs 25%, P = .028). VTE patients had a longer hospital stay (10 vs 7 days, P < .05) and higher mortality rate (6.3% vs 0.7%, P < .01). Multivariate analysis demonstrated osteoporosis, lack of physical labor, and increased SVA correction were independent predictors of VTE (r2 = .11, area under the curve = 0.74, P < .05). Conclusions:The incidence of VTE in ASD is 4.3% with a DVT rate of 1.9% and PE rate of 2.4%. Osteoporosis, lack of physical labor, and increased SVA correction were independent predictors of VTE. Patients with VTE had a higher mortality rate compared with non-VTE patients
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