[Finite element analysis on biomechanical properties of medial collateral ligament of elbow joint under different flexion angles].

Three-dimensional finite element model of elbow was established to study the effect of medial collateral ligament (MCL) in maintaining the stability of elbow joint. In the present study a three-dimensional geometric model of elbow joint was established by reverse engineering method based on the computed tomography (CT) image of healthy human elbow. In the finite element pre-processing software, the ligament and articular cartilage were constructed according to the anatomical structure, and the materials and contacts properties were given to the model. In the neutral forearm rotation position and 0° flexion angle, by comparing the simulation data of the elbow joint with the experimental data, the validity of the model is verified. The stress value and stress distribution of medial collateral ligaments were calculated at the flexion angles of elbow position in 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, respectively. The result shows that when the elbow joint loaded at different flexion angles, the anterior bundle has the largest stress, followed by the posterior bundle, transverse bundle has the least, and the stress value of transverse bundle is trending to 0. Therefore, the anterior bundle plays leading role in maintaining the stability of the elbow, the posterior bundle plays supplementary role, and the transverse bundle does little. Furthermore, the present study will provide theoretical basis for clinical recognizing and therapy of elbow instability caused by medial collateral ligament injury.

[Finite element analysis of male lower urinary tract based on the collodion slice images].

Males typically have high rates of morbidity of primary bladder neck obstruction, while the existing urodynamic examination is invasive and more likely to cause false diagnosis. To build a non-invasive biomechanical detecting system for the male lower urinary tract, a finite element model for male lower urinary tract based on the collodion slice images of normal male lower urinary tract was constructed, and the fluid-structure interaction of the lower urinary tract was simulated based on the real urination environment. The finite element model of the lower urinary tract was validated by comparing the clinical experiment data with the simulation result. The stress, flow rate and deformation of the lower urinary tract were analyzed, and the results showed that the Von Mises stress and the wall shear stress at the membrane sphincter in the normal male lower urinary tract model reached a peak, and there was nearly 1 s delay than in the bladder pressure, which helped to validate the model. This paper lays a foundation for further research on the urodynamic response mechanism of the bladder pressure and flow rate of the lower urinary tract obstruction model, which can provide a theoretical basis for the research of non-invasive biomechanical detecting system.

Clinical performance of multiplex high-risk e6 mrna expression in comparison with hpv dna subtypes for the identification of women at risk of cervical cancer.

We compared multiplex E6 messenger ribonucleic acid (mRNA) tests using real-time quantitative reverse transcriptase polymerase chain reactions (PCR) with human papillomavirus (HPV) DNA subtypes using a MY11/GP6+ PCR-based reverse-blot assay to identify cervical intraepithelial neoplasias of grade 2 or worse (CIN2+). In total, 684 women were studied, of whom 377 (55%) were diagnosed with CIN2+ histologically. The specificity of HPV mRNA to predict histological CIN2+ was higher than that of HPV DNA (81.3% vs. 44.2%). The odds ratios (ORs) to predict histological CIN2+ in women with positive for type 16, 18, 31, and 45 E6 mRNA or by HPV DNA detection were 7.1 (95% confidence interval [CI] 3.9-13.1) and 2.5 (95%CI 1.9-3.5), respectively, compared to those with negative for E6 mRNA or HPV DNA. The OR to predict histological CIN2+ in women with a cytological grade

Overexpressing Ferredoxins in Chlamydomonas reinhardtii Increase Starch and Oil Yields and Enhance Electric Power Production in a Photo Microbial Fuel Cell.

Ferredoxins (FDX) are final electron carrier proteins in the plant photosynthetic pathway, and function as major electron donors in diverse redox-driven metabolic pathways. We previously showed that overexpression of a major constitutively expressed ferredoxin gene PETF in Chlamydomonas decreased the reactive oxygen species (ROS) level and enhanced tolerance to heat stress. In addition to PETF, an endogenous anaerobic induced FDX5 was overexpressed in transgenic Chlamydomonas lines here to address the possible functions of FDX5. All the independent FDX transgenic lines showed decreased cellular ROS levels and enhanced tolerance to heat and salt stresses. The transgenic Chlamydomonas lines accumulated more starch than the wild-type line and this effect increased almost three-fold in conditions of nitrogen depletion. Furthermore, the lipid content was higher in the transgenic lines than in the wild-type line, both with and without nitrogen depletion. Two FDX-overexpressing Chlamydomonas lines were assessed in a photo microbial fuel cell (PMFC); power density production by the transgenic lines was higher than that of the wild-type cells. These findings suggest that overexpression of either PETF or FDX5 can confer tolerance against heat and salt stresses, increase starch and oil production, and raise electric power density in a PMFC.

Effect of synthesis temperature on the structural morphology of a metal-organic framework and the capacitor performance of derived cobalt-nickel layered double hydroxides.

Three-dimensional interconnected nickel-cobalt layered double hydroxides (NiCo-LDHs) were prepared on nickel foam by ion exchange using a cobalt-based metal-organic framework (Co-MOF) as a template at different temperatures. The effects of the Co-MOF preparation temperature on the growth, mass, morphology, and electrochemical properties of the Co-MOF and derived NiCo-LDH samples were studied. The synthesis temperature from 30 to 50 °C gradually increased the mass of the active material and the thickness of the Co-MOF sheets grown on the nickel foam. The higher the temperature is, the larger the proportion of Co3+. ß-Cobalt hydroxide (ß-Co(OH)2) sheets were generated above 60 °C. The morphology and mass loading pattern of the derived flocculent layer clusters of NiCo-LDH were inherited from metal-organic frameworks (MOFs). The areal capacitance of NiCo-LDH shows an inverted U-shaped curve trend with increasing temperature. The electrode material synthesized at 50 °C had a tremendous specific capacitance of 7631 mF·cm-2 at a current density of 2 mA·cm-2. The asymmetric supercapacitor assembled with the sample and active carbon (AC) achieved an energy density of 55.0 Wh·kg-1 at a power density of 800.0 W·kg-1, demonstrating the great potential of the NiCo-LDH material for energy storage. This work presents a new strategy for designing and fabricating advanced green supercapacitor materials with large power and energy densities.

Overexpression of ferredoxin, PETF, enhances tolerance to heat stress in Chlamydomonas reinhardtii.

Reactive oxygen species (ROS) produced by plants in adverse environments can cause damage to organelles and trigger cell death. Removal of excess ROS can be achieved through the ascorbate scavenger pathway to prevent plant cell death. The amount of this scavenger can be regulated by ferredoxin (FDX). Chloroplastic FDXs are electron transfer proteins that perform in distributing photosynthetic reducing power. In this study, we demonstrate that overexpression of the endogenous photosynthetic FDX gene, PETF, in Chlamydomonas reinhardtii could raise the level of reduced ascorbate and diminish H2O2 levels under normal growth conditions. Furthermore, the overexpressing PETF transgenic Chlamydomonas lines produced low levels of H2O2 and exhibited protective effects that were observed through decreased chlorophyll degradation and increased cell survival under heat-stress conditions. The findings of this study suggest that overexpression of PETF can increase the efficiency of ROS scavenging in chloroplasts to confer heat tolerance. The roles of PETF in the downregulation of the ROS level offer a method for potentially improving the tolerance of crops against heat stress.

Highly effective transfer of micro-LED pixels to the intermediate and rigid substrate with weak and tunable adhesion by thiol modification.

Based on transfer printing technology, micro-LED pixels can be transferred to different types and sizes of driving substrates to realize displays with different application scenarios. To achieve a successful transfer, GaN-based micro-LEDs first need to be separated from the original epitaxial substrate. Here, micro-LED pixels (each size 25 µm × 30 µm) on the sapphire substrate were transferred to a flexible semiconductor wafer processing (SWP) tape that is strongly sticky by conventional laser lift-off (LLO) techniques. The pixels on the SWP tape were then transferred by using a sacrificial layer of non-crosslinked oligomeric polystyrene (PS) film onto the intermediate and rigid substrate (IRS) with weak and tunable adhesion by thiol (-SH) modification. The electrode of the micro-LED is Au metal, which forms Au-S bonds with the surface of the IRS to fix the pixels. The rigid substrate helps ensure that the pixel spacing is almost unchanged during the stamp transfer process, and the weak and tunable adhesion facilitates the pixels being picked up by the stamp. The experimental results demonstrate that the pixels can be efficiently transferred to the IRS by LLO and sacrificial layer-assistance, which will provide the possibility of achieving the further transfer of pixels to different types and sizes of driving substrates by a suitable transfer stamp. The transfer process details are discussed, which can provide insights into the transfer of micro-nano devices through polymer sacrificial layers.

[Analysis on work related fatigue among prison police and mental medical staffs].

OBJECTIVE: To investigate the work related fatigue among prison police and mental medical staffs; to compare the social support between two groups; to develop specific intervention strategies in the future. METHODS: The Chinese Maslach Burnout Inventory (CMBI) and the Social Support Rating Scale (SSRS) were applied to 100 prison police and 100 mental medical staffs respectively. Their status of work related fatigue and relevant social support were analyzed accordingly. RESULTS: 1) The level of fatigue among prison police was higher than mental medical staffs (P < 0.05); 2) The factor scores of "emotional burnout" and "depersonalization" among prison police were higher than that among mental medical staffs (P < 0.05). There was no significant difference between the two groups on the "decreased sense of achievement" (P > 0.05); 3) The level of social support in the prison police was higher than that in the mental medical staffs (P < 0.05). CONCLUSION: Both prison police and mental medical staffs were vulnerable to suffering from fatigue. However, the details and relevant social support between these two groups were different. Active intervention should be taken for different occupation.

Effect of the medial collateral ligament and the lateral ulnar collateral ligament injury on elbow stability: a finite element analysis.

Ligaments are the most important stabilizer of elbow. However, the stress of ligaments is hard to measure because of the complex biomechanical environment in the elbow. Our objective was to develop a human elbow finite element model and to validate it by a comparison with previous experimental data. Then several different ligaments injury conditions and elbow flexion were simulated to analyse the elbow instability and to stress the biomechanical consequences. The computational investigation of different effects of ligament constraints of elbow was studied by means of finite element analysis. The stress of the anterior bundle was almost greater than other ligaments in all conditions, which played the most important role during the elbow flexion. The posterior bundle was the secondary stabilizer during flexion after the anterior bundle. The lateral ulnar collateral ligament (LUCL) injury could result in an increase of the ulnar cartilage stress. The anterior bundle and the LUCL were recommended to be repaired in elbow joint dislocations and fractures. This study could help understand the dynamic effects of ligaments on the joint over the entire extension by investigating the tissue stress.

Periodic folding of a falling viscoelastic sheet.

A viscoelastic solid sheet fed from a certain height towards a rigid horizontal plane folds on itself provided that there is no slip. This phenomenon commonly occurs in the manufacturing process of textile and paper products. In this paper we apply a particle dynamics model to investigate this phenomenon. At a low feeding velocity and low viscosity, the inertial effect and the viscous dissipation within the sheet are negligible, and our model successfully reproduces the existing quasistatic results in the gravitational regime. As the feeding velocity and the viscosity of the sheet increase, the folding process changes significantly. The length of the folds decrease and the "rolling back" motion of the sheet vanishes. In the inertial regime, a scaling law between the fold length and the feeding velocity is derived by balancing the kinetic energy and the elastic bending energy involved in folding, which is verified by the simulation. It is found that above a critical feeding velocity, the folding morphology transforms from line contact into point contact with the sheet exhibiting a lemniscate-like pattern. Finally, a phase diagram for the folding morphology is constructed. The results presented in this work may offer some insights into the high-speed manufacturing of paper and fabric sheets.

Multi-component heteroarene couplings via polarity-reversed radical cascades.

A multi-component radical addition strategy enables difunctionalization of alkenes with heteroarenes and a variety of radical precursors, including N3, P(O)R2, and CF3. This unified approach for coupling diverse classes of electrophilic radicals and heteroarenes to vinyl ethers allows for direct, vicinal C-C as well as C-N, C-P, and C-Rf bond formation.

Effects of interface sliding on the formation of telephone cord buckles.

Sliding at interface during thin film buckling was reported by recent atomistic simulations. A stability analysis under the Föppl-von Kármán plate theory is performed to investigate the effect of interface sliding on the transition of a straight-sided blister to the telephone cord buckle in biaxially compressed thin films on rigid substrates. It is shown that the critical stress and the wavelength of the telephone cord buckle significantly increase as the interface sliding is noticeable in comparison with the constant values derived from previous classic analysis without interface sliding. Our theoretic analysis is further validated by results from numerical simulations based on our recently developed continuum model of nonlinear buckling. The results indicate that the wavelength variation in the telephone cord buckle observed in experiments may be due to interface sliding.