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Maria Immaculata Arifin Samia Hannaoui Sheng Chun Chang Simrika Thapa Hermann M. Schatzl Sabine Gilch 《International journal of molecular sciences》2021,22(5)
Chronic wasting disease (CWD) is a prion disease found in both free-ranging and farmed cervids. Susceptibility of these animals to CWD is governed by various exogenous and endogenous factors. Past studies have demonstrated that polymorphisms within the prion protein (PrP) sequence itself affect an animal’s susceptibility to CWD. PrP polymorphisms can modulate CWD pathogenesis in two ways: the ability of the endogenous prion protein (PrPC) to convert into infectious prions (PrPSc) or it can give rise to novel prion strains. In vivo studies in susceptible cervids, complemented by studies in transgenic mice expressing the corresponding cervid PrP sequence, show that each polymorphism has distinct effects on both PrPC and PrPSc. It is not entirely clear how these polymorphisms are responsible for these effects, but in vitro studies suggest they play a role in modifying PrP epitopes crucial for PrPC to PrPSc conversion and determining PrPC stability. PrP polymorphisms are unique to one or two cervid species and most confer a certain degree of reduced susceptibility to CWD. However, to date, there are no reports of polymorphic cervid PrP alleles providing absolute resistance to CWD. Studies on polymorphisms have focused on those found in CWD-endemic areas, with the hope that understanding the role of an animal’s genetics in CWD can help to predict, contain, or prevent transmission of CWD. 相似文献
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Mohd Firdaus Omar Hazizan Md Akil Zainal Arifin Ahmad Shahrom Mahmud 《Polymer Engineering and Science》2014,54(4):949-960
The effect of strain rate is widely recognized as an essential factor that influences the mechanical properties of polymer matrix composites. Despite its importance, no previous work has been reported on the high‐strain rate behavior of polypropylene/zinc oxide nanocomposites. Based on this, static and dynamic compression properties of polypropylene/zinc oxide nanocomposites, with particle contents of 1%, 3%, and 5% by weight, were successfully studied at different strain rates (i.e., 0.01 s?1, 0.1 s?1, 650 s?1, 900 s?1, and 1100 s?1) using a universal testing machine and a split Hopkinson pressure bar apparatus. For standardization, approximately 24 nm of zinc oxide nanoparticles were embedded into polypropylene matrix for each of the tested polypropylene/zinc oxide nanocomposites. Results show that the yield strength, the ultimate strength, and the stiffness properties, of polypropylene/zinc oxide nanocomposites, were greatly affected by both particle loading and applied strain rate. Furthermore, the rate sensitivity and the absorbed energy of all tested specimens showed a positive increment with increasing strain rate, whereas the thermal activation volume showed a contrary trend. In addition, the fractographic analysis and particle dispersion of all composite specimens were successfully obtained using a field emisission scanning electron microscopy. POLYM. ENG. SCI., 54:949–960, 2014. © 2013 Society of Plastics Engineers 相似文献
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Nano-Micro Letters - Electroceramic calcium copper titanates (CaCu3Ti4O12, CCTO), with high dielectric permittivities (ε) of approximately 105 and 104, respectively, for single crystal and... 相似文献
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Optical and photoelectrochemical (PEC) properties of a TiO2 thin film electrode doped with a new variation of ruthenium–(4,4′dimethyl-2,2′-bipyridine)–isothiocyanato–tungsten[bis-(phenyl-1,2-ethilenodithiolenic)] bimetallic complex (BM) were investigated. Physical adsorption process was used to immobilise the BM on the TiO2 thin film. Crystalline structure and surface morphology of the thin films were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) techniques. N3 commercial dye was also used as a dopant to the TiO2 films for comparison. Light absorption spectra and bandgap energy of the thin films were determined using UV–vis spectroscopy. Light absorption of the TiO2 thin film doped with BM was better than the TiO2 doped with the N3 commercial dye. Band edges of the TiO2 thin film and the BM were determined via cyclic voltammetry (CV) measurements. Top-edge of the BM valence band (VB) was more positive than the bottom edge of the conduction band (CB) of the TiO2 film (vs. NHE). PEC analysis indicated that photocurrent of TiO2 doped with the BM electrode was higher than TiO2 doped with the N3 in the beginning of illumination process, but the performance was defeated after a while. Based on the optical properties and the PEC analyses, BM has potential to be used as dye sensitisers for a PEC cell. 相似文献
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Rensheng Deng Davis Yohanes Arifin Mak Ye Chyn Chi-Hwa Wang 《Chemical engineering science》2010,65(16):4598-4605
We present a study on Taylor vortex flow in between a rotating inner cylinder and a stationary outer cylinder with vertical or horizontal baffles. A mineral oil is used as the working fluid in the annular channel of 60 mm in height and 11.6 mm in gap width. The flow pattern in the annulus is investigated by particle image velocimetry (PIV) and computational fluid dynamics (CFD). Both the experimental and simulation results show that the presence of vertical baffles influences the vertical positions of vortices—it is primarily significant for the bottom vortex. Increasing number of vertical baffles gradually decreases the azimuthal variation in the vertical position. The baffles also lead to the occurrence of a circulation flow immediately upstream and downstream each baffle plate in the radial–azimuthal plane. On the other hand, an annular horizontal baffle with sufficient width alters the vortex structure in the gap, for instance, fewer vortices are observed. With two horizontal baffles in the annulus, the flow pattern is largely affected by the baffle width and the distance between the two baffles. This study provides a better understanding of Taylor vortex in presence of internal baffles, which will be important for practical applications of Taylor vortex devices. 相似文献
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Wan Fahmin Faiz Wan Ali Mohamadarif Othman Mohd Fadzil Ain Norazharuddin Shah Abdullah Zainal Arifin Ahmad 《Journal of the European Ceramic Society》2013,33(7):1317-1324
Y3Fe5O12 (YIG) prepared by conventional solid-state method can rarely be of high purity. However, this study suggests that high purity YIG can be produced via conventional solid-state methods, through stoichiometry modification. This is achieved by adding various amounts of excess Fe2O3 to control the YIG stoichiometric ratios. In this work, ferrite and yttria were calcined at 1100 °C (for 8 h) and sintered at 1420 °C (6 h). In most samples, the formation of YIG, with YFeO3 (YIP) and/or Fe2O3 as associated phases were detected. Uniform microstructures of YIG are also observed. YIP phase in YIG is found to be inversely related to the addition of excess Fe2O3, up to 8 wt%. At above 8 wt% Fe2O3 addition, YIP disappears, leaving unreacted excess Fe2O3 as a new associated phase. From the investigation, it is safe to conclude that the purity of YIG can be increased with the addition of excess Fe2O3. 相似文献
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