Ultraviolet (UV) radiation, in particular the midwavelength range (UVB; 290-320 nm), is one of the most significant risk factors for the development of nonmelanoma skin cancer. UVB radiation-induced immunosuppression, which occurs in both humans and laboratory animals, contributes to their pathogenesis. However, there are conflicting reports on the relative role of CD4(+) and CD8(+) T cells in UVB induced skin cancer. The purpose of this study was to delineate the contribution of these two cell subpopulations to UVB induced immunosuppression and tumor development using C3H/HeN (WT), CD4 knockout (CD4(-/-) ) and CD8 knockout (CD8(-/-) ) mice. We observed that UVB induced skin carcinogenesis was retarded in terms of number of tumors per group, tumor volume and percentage of mice with tumors, in mice deficient in CD4(+) T cells compared with wild-type mice, whereas significantly greater (P < 0.05) numbers of tumors occurred in CD8(-/-) mice. These results indicate that, CD4(+) T cells promote tumor development while CD8(+) T cells have the opposite effect. Further, we found that CD4(+) T cells from tumor-bearing mice produced interleukin (IL)-4, IL-10, and IL-17 whereas CD8(+) T cells produced interferon-γ. Manipulation of T-cell subpopulations that are induced by UVB radiation could be a means of preventing skin cancers caused by this agent. 相似文献
This study develops the extended Kantorovich method (EKM) to provide a closed form semi analytical solution for the bending analysis of two edge-bonded thin rectangular plates. The constituent plates could be different in thickness, length, material, loading conditions, and Winkler foundation’s stiffness. A combination of clamp, free, and simply supports are applied to the structure. The shared edge in the composite plate is assumed to be perfectly bonded. By applying the EKM together with the idea of weighted residual technique, two sets of ODEs are obtained. Bending is assumed to remain continuous on the bonded edge. The EKM procedure is modified by applying the coordinate of an arbitrary shared point in the boundary conditions for the shared edge, to relate the bending of the two plates. The ODEs are solved iteratively to obtain the deflection function in a fast convergence trend. Two examples of aluminium-steel plate and functionally graded material-steel plate are considered. The deflection results from the boundary modified EKM (BM-EKM) are in high agreement with the finite element solution results. The bending of stepped plates is a special case of the current study. The suggested BM-EKM strengthens the EKM’s ability for solving complex jointed/bonded structures in structural analyses.
We present a thorough computational study of transition metal-doped zeolite and aluminophosphate (AlPO) frameworks. The structural and electronic chemistry of the dopants is examined with ab initio quantum mechanical calculations, and the results correlated with the Brønsted and Lewis acid strength, and with the redox potential of the dopant ions in the framework. The energetics of doping is provided, and is employed to analyze the mode of dopant incorporation, and its site ordering in the microporous framework. In total, 23 dopant ions are examined in the isostructural framework of chabasite and AlPO-34. These cover most of the isomorphous framework replacements known to occur experimentally, but also framework replacements that have not yet been achieved. In this case, ab initio modeling techniques are employed in a predictive way. Finally, we present a computational study of the alkene epoxidation on titanosilicates, that covers the whole catalytic cycle. 相似文献
Series of functional multidendate ligands based on pyrazole and amino acid derivatives were prepared in good and excellent yields (75–5%) by condensation of one equivalent of amino acid ester hydrochloride substrates with two equivalents of (3,5-dimethyl-1H–pyrazol-1-yl)methanol. These tridentate functionalized compounds and their starting materials were screened for their antifungal activities against Fusarium oxysporum f.sp. albedinis and the yeast of Saccharomyces cerevisiae. Considerable activities were recorded with respect to the two studied microorganisms. 相似文献
Journal of Sol-Gel Science and Technology - New carbon aerogels were prepared using Novolac sol as precursor. The elaboration process and the structural characterizations of these porous carbon... 相似文献
The effect of noise on the performance of Schottky Barrier Carbon Nanotube Field Effect Transistors (SB-CNTFETs) has been
investigated under various bias conditions. In order to calculate the noise power spectral density, the Non-Equilibrium Green’s
Function formalism (NEGF) is used to obtain the transmission coefficient and the number of carriers inside the channel. Results
are presented in two sections: In the first section the Hooge’s empirical rule is used to investigate the flicker noise properties
of SB-CNTFETs with defects in the gate oxide region, while in the second section the thermal and shot noise properties of
SB-CNTFETs are studied. Finally, the best bias points in the ON and OFF states have been suggested according to the total
noise power spectral density and the device signal to noise ratio.
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The effects of the addition of three types of surfactants (cationic, anionic, non-ionic) at different concentrations in the plating bath on the deposition rate, PTFE content and surface morphology of electroless Ni-P/PTFE composite coatings were investigated. It was demonstrated that the cationic and non-ionic surfactants created a uniform distribution of PTFE particles in the coatings. The effects of the surfactant type and concentration on the corrosion properties of Ni-P/PTFE coatings were also studied. The corrosion resistance was increased by the incorporation of PTFE particles into the Ni-P matrix. The level of improvement depended largely on the type and concentration of the applied surfactants. 相似文献
Deutsch’s entropic uncertainty relation is examined by using two experiments in which the spin of a single spin-half particle is detected after passing through two Stern-Gerlach apparatuses in two successive times. Two experiments differ only in the angle settings of the Stern-Gerlach apparatuses. In the general case where the angles are arbitrarily arranged, Deutsch’s inequality is violated. 相似文献