Dependence of grip strength on shoulder position and its implications for ergonomics practice

Grip strength (GS) variability due to positional changes in the upper extremity joints is of importance while designing workstations and work methods. This study was conducted to analyze the GS variations due to positional changes at shoulder joint when some important variables were under control. The GSs of dominant and nondominant hands were measured in eight shoulder (0°, 45°, 90°, and 135° of flexion and abduction) and standard test positions (STP). One hundred and thirteen subjects 20–30 years old completed the study. At the dominant side, no significant difference was observed in the pairwise comparisons between STP and the others. Maximum and minimum GSs were obtained in 0° abduction and 45° flexion and abduction, respectively. At the nondominant side, GSs were significantly lower (p < 0.001) in the corresponding test positions and demonstrated more variability. The findings of this study can contribute to the available knowledge to guide occupational ergonomists in their practices.     

Hemodialysis‐related headache

Headache is one of the most frequently encountered neurological symptoms during hemodialysis. According to International Classification of Headache criteria dialysis‐related headache was defined as the headache occurring during hemodialysis with no specific characteristic. It resolves spontaneously within 72 hours after the hemodialysis session ends. There are few studies in the literature investigating the clinical features of dialysis headache. The pathophysiology of hemodialysis‐related headache is not known, but various triggering factors have been identified, including changes in blood pressure, serum sodium and magnesium levels during hemodialysis sessions, caffeine deprivation and stress. The aim of this article is to evaluate and analyze features of headache in patients undergoing hemodialysis.     

Influence of Mg doping on the structural,optical, and electrical properties of Zn0.95Li0.05O Nanoparticles

This study investigates the effect of Li and Mg codoping on the structural, optical, and electrical properties of the ZnO. Zn_0.95−xLi_0.05Mg_xO (x = 0.00, 0.01, 0.02, 0.03) nanoparticles are synthesized by hydrothermal method. X-ray diffraction (XRD) results confirmed that all samples are polycrystalline with a hexagonal-wurtzite structure. The surface morphology of the samples were examined by Scanning Electron Microscopy (SEM). The SEM analysis showed that all samples exhibit cheese-like plates and the plate sizes increase with Mg addition. Optical properties were examined by UV-VIS diffuse reflectance spectroscopy. The optical measurements indicate that the reflectance edge of the samples have red shift up to 2% Mg doping level, but blue-shift for 3% Mg doping. The optical band gap of Zn_0.95−xLi_0.05Mg_xO nanostructures are calculated as 3.227, 3.214, 3.209, and 3.221 eV with x = 0.00, 0.01, 0.02, 0.03 respectively. Electrical properties including the carrier concentration, Hall mobility, and resistivity were studied using Van-der Pauw method. The temperature resistivity curves of the samples shown typical semiconductor behavior. The carrier concentration decreases with increasing doping level up to 2% Mg, and it slightly increases for 3% Mg. The variation of the Hall mobility for the samples is inversely proportional to the carrier concentration.     

锦纶-聚酯复合帘线的有限元分析

轮胎制造行业大量使用各种纤维帘线,然而纤维帘线的设计、开发和制造是一个非常复杂的过程,工程技术人员通常要开展一系列严谨而且复杂的工作,如建立模型、数据分析、结构设计、样品试制和产品测试等,采取不同的方法和技术措施解决过程中存在的各种问题,最后才能确定帘线制造的最佳方案.有限元分析是解决这种具有挑战性工程技术问题最有效的方法之一.尤其是近年来计算能力和智能工具技术水平的快速发展,促进了有限元分析技术的推广应用.     

Proximate composition and fatty acid profile of three different fresh and dried commercial sea cucumbers from Turkey

Proximate composition and fatty acid (FA) profile of three commercial sea cucumbers; Holothuria tubulosa, Holothuria polii and Holothuria mammata caught from Aegean Sea of Turkey were analysed. The effects of regional variation and drying process on FA composition were also investigated. Moisture, protein, fat and ash contents of the species ranged between 81.24% and 85.24%, 7.88% and 8.82%, 0.09% and 0.18%, and 5.13% and 7.85%, respectively, with a significant changes among species (P < 0.05) with some exceptions. Although FA values varied significantly (P < 0.05) among species and regions, the changes for most FA types representing the same region for different species were not significantly different. Total polyunsaturated fatty acids (PUFA) were found to be higher than total saturated (SFA) and monosaturated FAs (MUFA) accounting for 53.0–62.12% for ∑PUFA, 13.28–16.41% for ∑MUFA and 13.99–19.21% for ∑SFA. While some individual SFAs and PUFAs decreased after drying process, various individual FAs of MUFA increased in their amounts (P < 0.05). Among PUFAs, the highest mean value of eicosapentaenoic acid and docosahexaenoic acid for all regions were determined for H. polii as 7.25% and H. tubulosa as 12.37% in fresh samples, respectively. This study represents new information relating to FA contents and drying effect on FA profile for these species.     

The study of MIG weldability of heat-treated aluminum alloys

In this article, Metal Inert Gas (MIG) weldability of commercially received and aged samples of 6061-T₆ and 7075-T₆₅₁ aluminum alloys was investigated. The welding joints were prepared in ten different combinations. Microstructure, microhardness, EDX, energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses were used in order to evaluate the effect of aged heat treatment on the performance of welded joints. In addition, the mechanical properties of welding joints were characterized using the tensile and microhardness tests. In conclusion, it was shown that prewelding aging heat treatment improves the mechanical properties of welding joints.     

Plasma polymerization‐modified bacterial polyhydroxybutyrate nanofibrillar scaffolds

The design and the development of novel scaffold materials for tissue engineering have attracted much interest in recent years. Especially, the prepared nanofibrillar scaffold materials from biocompatible and biodegradable polymers by electrospinning are promising materials to be used in biomedical applications. In this study, we propose to produce low‐cost and cell‐friendly bacterial electrospun PHB polymeric scaffolds by using Alcaligenes eutrophus DSM 545 strain to PHB production. The produced PHB was characterized by Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Nanofibrous scaffolds were fabricated via electrospinning method that has a fiber diameter approximately 700–800 nm. To investigate cell attachment, cell growth, and antioxidant enzyme activity on positively and negatively charged PHB scaffold, PHB surface was modified by plasma polymerization technique using polyethylene glycol (PEG) and ethylenediamine (EDA). According to the results of superoxide dismutase (SOD) activity study, PEG‐modified nanofibrillar scaffolds indicated more cellular resistance against oxidative stress compared to the EDA modification. As can be seen in cell proliferation results, EDA modification enhanced the cell proliferation more than PEG modification, while PEG modification is better as compared with nonmodified scaffolds. In general, through plasma polymerization technique, surface modified nanofibrillar structures are effective substrates for cell attachment and outgrowth. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Ambient Vibration Tests of a Steel Footbridge

The paper presents analytical and experimental modal analysis of a steel footbridge for modal parameter identification. 3D finite element model is established for the steel footbridge based on the design drawing and modal parameters are obtained from deformed configurations. The field test is carried out by ambient vibration test under human walking excitation. Both Peak Picking method in the frequency domain and the Stochastic Subspace Identification method in the time domain are used for the output-only modal identification. From the study, good agreement is found between mode shapes, but some differences in the natural frequencies and analytical frequencies are bigger.     

Viscoelastic Properties of a Biological Hydrogel Produced from Soybean Oil

Hydrogels formed from biopolymers or natural sources have special advantages because they may have biodegradable and biocompatible properties. The viscoelastic properties of a newly developed biological hydrogel made from epoxidized soybean oil (ESO) were investigated. The material called HPESO is a hydrolytic product of polymerized ESO (PESO). HPESO exhibited viscoelastic solid or gel behavior above 2% (wt. %) concentration at room temperature and viscous liquid behavior at 55 °C. The thermal assembly disassembly reassembly function of the HPESO hydrogel was completely reversible. The viscoelastic properties of HPESO were dependent on concentration. Analysis of modulus and concentration dependence and stress relaxation measurement indicated that HPESO was a physical gel where the cross-linkers between the molecules were physical junctions. HPESO hydrogel also exhibited fast initial recovery of its viscoelastic properties after being subjected to mechanical shear disruption. The function and behavior of the HPESO hydrogel suggest that this biomaterial may be suitable for applications in drug delivery and scaffolds of bioengineering and tissue engineering. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by the USDA implies no approval of the product to the exclusion of others that may also be suitable.