3,506 research outputs found
Prosthesis replacement in Mason III radial head fractures: A meta-analysis
AbstractIntroductionThis present study was to evaluate the clinical efficacy of prosthesis replacement (PR) for patients with Mason III radial head fractures (RHF) compared with open reduction and internal fixation (ORIF).MethodsWe retrieved the relevant trials up to September 2013 from several public databases, mainly including PubMed, Embase, Springer, Elsevier Science Direct, Cochrane Library, Google scholar, CNKI and Wanfang database. Weighted mean difference (WMD) or odds ratio (OR) and their 95% confidence intervals (CI) were calculated to compare the clinical outcomes between PR and ORIF.ResultsA total of 9 studies including 365 patients with Mason III RHF (169 patients treated with PR and 196 patients treated with ORIF) were reanalyzed in the meta-analysis. The results showed that the patients with Mason III RHF receiving PR, compared with the ORIF ones, had a significantly higher percentage of postoperative excellent and good rate (OR=3.48, 95% CI=1.98 to 6.11, P<0.0001), better Broberg and Morrey elbow scores (WMD=9.79, 95% CI=4.22 to 15.36, P=0.0006) and significantly lower postoperative complications (OR=0.33, 95% CI=0.16 to 0.69, P=0.003).ConclusionsAlthough the results of this study supported the use of PR in the treatment of Mason III RHF in Chinese population with short-term outcomes, the evidences are of low quality and further studies were required for confirming these results in the longer term on other populations.Level of evidenceLevel III. Low power meta-analysis
Temperature dependence of electron-spin relaxation in a single InAs quantum dot at zero applied magnetic field
The temperature-dependent electron spin relaxation of positively charged
excitons in a single InAs quantum dot (QD) was measured by time-resolved
photoluminescence spectroscopy at zero applied magnetic fields. The
experimental results show that the electron-spin relaxation is clearly divided
into two different temperature regimes: (i) T < 50 K, spin relaxation depends
on the dynamical nuclear spin polarization (DNSP) and is approximately
temperature-independent, as predicted by Merkulov et al. (ii) T > about 50 K,
spin relaxation speeds up with increasing temperature. A model of two LO phonon
scattering process coupled with hyperfine interaction is proposed to account
for the accelerated electron spin relaxation at higher temperatures.Comment: 10 pages, 4 figure
Large-time Behavior of Solutions to the Inflow Problem of Full Compressible Navier-Stokes Equations
Large-time behavior of solutions to the inflow problem of full compressible
Navier-Stokes equations is investigated on the half line .
The wave structure which contains four waves: the transonic(or degenerate)
boundary layer solution, 1-rarefaction wave, viscous 2-contact wave and
3-rarefaction wave to the inflow problem is described and the asymptotic
stability of the superposition of the above four wave patterns to the inflow
problem of full compressible Navier-Stokes equations is proven under some
smallness conditions. The proof is given by the elementary energy analysis
based on the underlying wave structure. The main points in the proof are the
degeneracies of the transonic boundary layer solution and the wave interactions
in the superposition wave.Comment: 27 page
Enhancing the Production of a Novel Exopolysaccharide by Bacillus mucilaginosus CGMCC5766 Using Statistical Experiment Design
Purpose: To improve the production of a novel exopolysaccharide (EPS) by Bacillus mucilaginosus CGMCC5766.Methods: The culture medium for production of EPS was optimized using statistical experiment design. Sucrose, CaCO3 and K2HPO4 were found to be the key factors based on the results obtained from Plackett–Burman experimental design. The optimal concentration range of the three factors was examined by the steepest ascent path, and then the optimum concentration was further investigated through response surface methodology. Validation experiments were also carried out to establish the adequacy and accuracy of the model obtained.Results: Under optimal conditions (sucrose 61.31 g/l, CaCO3 5.06 g/l and K2HPO4 0.17 g/l), EPS concentration achieved 22.04 g/l, which was about 1.6-fold increase compared with that using the original medium. EPS concentration in 5-l fermenter reached 23.46 ± 0.76 g/l.Conclusion: The optimization medium is considered fundamental and useful for the development of B. mucilaginosus CGMCC5766 cultivation process for efficient production of EPS on a large scale.Keywords: Bacillus mucilaginosus CGMCC5766, Exopolysaccharide, Medium, Optimization, Statistical experiment desig
Over-expression of NAD kinase in Corynebacterium crenatum and its Impact on L-Arginine Biosynthesis
Purpose: To improve the biosynthesis of L-arginine by overexpressing homologous NAD kinase (ppnk) in Corynebacterium crenatum SYPA5-5 and to study its impact in presence of high (HOS) and low oxygen supply (LOS).Methods: A recombinant plasmid (pJC1-tac-ppnK) harboring homologous NAD kinase (ppnk) was constructed in a shuttle vector pJC1 and transferred in L-arginine producing strain Corynebacterium crenatum SYPA5-5. Furthermore, fermentation was performed by shake flask method with consecutive determination of cell growth and glucose concentration. NAD+ kinase activity was studied by stop method and NADP(H) concentrations were determined by spectrophotometric enzymatic cycling method. To check the biosynthesis of amino acids, HPLC method was used to determine extracellular amino acid concentrations.Results: In HOS condition, NAD+ kinase activity increased by 116 %, while intracellular concentrations of NADP+ and NADPH increased by 7.3 and 36.8 %, respectively. Whereas, in LOS condition , NAD+ kinase activity increased 49 % , with intracellular 14.67 and 15 % increases in NADP+ and NADPHrespectively. More importantly, recombinant strain could produce 26.47 and 11.36 g/L L-arginine in HOS and LOS respectively, which is higher than control strain value of 24.29 and 7.58 g/L respectively.Conclusion: These results suggest that altering the concentration of co-enzymes by NAD kinase in Corynebacterium crenatum is an effective way to increase NADP+ with concurrent production of NADPH for further enhanced L-arginine biosynthesis in Corynebacterium crenatum in both conditions of high and low oxygen supply.Keywords: NAD kinase, PpnK, L-arginine, Corynebacterium crenatu
Magnetic field processing to enhance critical current densities of MgB2 superconductors
Magnetic field of up to 12 T was applied during the sintering process of pure
MgB2 and carbon nanotube (CNT) doped MgB2 wires. We have demonstrated that
magnetic field processing results in grain refinement, homogeneity and
significant enhancement in Jc(H) and Hirr. The Jc of pure MgB2 wire increased
by up to a factor of 3 to 4 and CNT doped MgB2 by up to an order of magnitude
in high field region respectively, compared to that of the non-field processed
samples. Hirr for CNT doped sample reached 7.7 T at 20 K. Magnetic field
processing reduces the resistivity in CNT doped MgB2, straightens the entangled
CNT and improves the adherence between CNTs and MgB2 matrix. No crystalline
alignment of MgB2 was observed. This method can be easily scalable for a
continuous production and represents a new milestone in the development of MgB2
superconductors and related systems
SQA-SAM: Segmentation Quality Assessment for Medical Images Utilizing the Segment Anything Model
Segmentation quality assessment (SQA) plays a critical role in the deployment
of a medical image based AI system. Users need to be informed/alerted whenever
an AI system generates unreliable/incorrect predictions. With the introduction
of the Segment Anything Model (SAM), a general foundation segmentation model,
new research opportunities emerged in how one can utilize SAM for medical image
segmentation. In this paper, we propose a novel SQA method, called SQA-SAM,
which exploits SAM to enhance the accuracy of quality assessment for medical
image segmentation. When a medical image segmentation model (MedSeg) produces
predictions for a test image, we generate visual prompts based on the
predictions, and SAM is utilized to generate segmentation maps corresponding to
the visual prompts. How well MedSeg's segmentation aligns with SAM's
segmentation indicates how well MedSeg's segmentation aligns with the general
perception of objectness and image region partition. We develop a score measure
for such alignment. In experiments, we find that the generated scores exhibit
moderate to strong positive correlation (in Pearson correlation and Spearman
correlation) with Dice coefficient scores reflecting the true segmentation
quality.Comment: Work in progress
Risk factors for candida infection of the genital tract in the tropics
Objective: To investigate the risk factors associated with candida infection of the genital tract in the tropics.Methods: We performed questionnaire survey and experiments at the Hainan branch of General Hospital of People’s Liberation Army, Hainan General Hospital and Sanya Maternity and Child Health Care Hospital in 2013. Controls were without Candida infection of genital tract, and cases had from Candida infection.Results: We recruited 689 cases and 652 controls. The average age of cases with Candida infection of the genital tract was higher than that of controls. In the multivariate modeling, marriage (adjusted odds ratio: 2.49, 95% confidential interval: 1.09-5.67) and vaginal lavage (adjusted odds ratio: 4.41, 95% confidential interval: 1.13-5.14) were significantly associated with Candida infection of genital tract in tropics.Conclusion: Candida infection was related with age. Marriage and Vaginal lavage were significant risk factors. Attention should be paid to health education for the prevention of these infections.Key word: Candida infection, risk factors, genital tract
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