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121.
A Childerstone H Takamatsu H Yang M Denyer RM Parkhouse 《Canadian Metallurgical Quarterly》1998,62(4):281-296
Infection of pigs with many strains of African Swine Fever Virus (ASFV) has been shown to cause a loss or marked decrease in the ability of splenocytes to respond to mitogens. These observations have been extended by cell fractionation and reconstitution experiments to show that the mitogen stimulated proliferative capacity of both the CD4+ and CD8+ T cells is affected. Similarly, monocytes which are directly infectable by virus, are functionally defective as antigen presenting cells when added to mitogen stimulated normal T cells. Interestingly, the same T cells which respond poorly in mitogenic assays can be activated by stimulation through the CD3 receptor. In contrast to the defective mitogenic response of T cells, B cell function, as assessed by stimulation through the CD40 ligand in vitro remains intact. There is no evidence for apoptosis in either the T cells or the B cells recovered from the spleens of ASFV infected animals 1-5 days following infection. Although the number of leucocytes which can be recovered from the infected spleen decreases rapidly with progression of the disease, the proportion of the different cell phenotypes remains constant. Thus decreased activity of lymphocytes in lymphoid tissue from ASFV infected animals appears to be directly attributable to infection of the monocytes. 相似文献
122.
Neurons in the central nucleus of the inferior colliculus (ICc) typically respond with phase-locked discharges to low rates of sinusoidal amplitude-modulated (SAM) signals and fail to phase-lock to higher SAM rates. Previous studies have shown that comparable phase-locking to SAM occurs in the dorsal nucleus of the lateral lemniscus (DNLL) and medial superior olive (MSO) of the mustache bat. The studies of MSO and DNLL also showed that the restricted phase-locking to low SAM rates is created by the coincidence of phase-locked excitatory and inhibitory inputs that have slightly different latencies. Here we tested the hypothesis that responses to SAM in the mustache bat IC are shaped by the same mechanism that shapes responses to SAM in the two lower nuclei. We recorded responses from ICc neurons evoked by SAM signals before and during the iontophoretic application of several pharmacological agents: bicuculline, a competitive antagonist for gamma-aminobutyric acid-A (GABAA) receptors; strychnine, a competitive antagonist for glycine receptors; the GABAB receptor blocker, phaclofen, and the N-methyl-D-aspartate (NMDA) receptor blocker, (-)-2-amino-5-phosphonopentanoic acid (AP5). The hypothesis that inhibition shapes responses to SAM signals in the ICc was not confirmed. In >90% of the ICc neurons tested, the range of SAM rates to which they phase-locked was unchanged after blocking inhibition with bicuculline, strychnine or phaclofen, applied either individually or in combination. We also considered the possibility that faster alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors follow high temporal rates of incoming excitation but that the slower NMDA receptors could follow only lower rates. Thus at higher SAM rates, NMDA receptors might generate a sustained excitation that "smears" the phase-locked excitation generated by the AMPA receptors. The NMDA hypothesis, like the inhibition hypothesis, was also not confirmed. In none of the cells that we tested did the application of AP5 by itself, or in combination with bicuculline, cause an increase in the range of SAM rates that evoked phase-locking. These results illustrate that the same response property, phase-locking restricted to low SAM rates, is formed in more than one way in the auditory brain stem. In the MSO and DNLL, the mechanism is coincidence of phase-locked excitation and inhibition, whereas in ICc the same response feature is formed by a different but unknown mechanism. 相似文献
123.
K. N. Pande D. R. Peshwe Anupama Kumar 《Transactions of the Indian Institute of Metals》2012,65(3):313-319
Polyamide (PA) is generally used in automotive applications in which the extensive mechanistic situations lead the material to wear. To deal with this situation, attempts are made to treat this material cryogenically using liquid nitrogen. The material is treated at different temperatures (?80, ?140 and ?185?°C) for stipulated time period (4, 8, 12, 16, 20 and 24?h) in the cryostat. Cryo-treated samples are then allowed to attain the ambient temperature and tested for studying the effect of cryogenic treatment. Selected material is also studied simultaneously for thermal ageing. The mechanical, thermal and structural properties of ??un-treated?? and ??cryo-treated?? PA are studied in a comparative manner. Mechanical properties like wear performance and tensile properties are evaluated. The morphological changes due to cryo-treatment are investigated using scanning electron microscopy. Structural characterization by X-ray diffraction and Fourier transform infrared spectroscopy revealed the change in % crystallinity, which is found to be the most important parameter responsible for enhancement of wear performance. In a similar way, thermal changes are also studied by using differential scanning calorimeter. Experimental data is evaluated for the polymer with improved structural, mechanical and thermal properties in order to get optimized parameters for the cryo-treatment. 相似文献
124.
Pande R Xie L Zagozdzon-Wosik W Nesteruk K Wosik J 《Applied physics letters》2012,100(6):63701-637014
We report on investigations of nonlinear radiofrequency responses of electrolytes with Na(+) and Cl(-) ions placed within gold electrodes of a capacitor. The sample was part of a frequency-adjustable inductance-capacitance-resistance (LCR) parallel resonant circuit, and measurements were carried out using the two frequencies intermodulation distortion technique. We employed double layer model to analyze the observed nonlinearities and their dependence on ionic concentration. Electrode-electrolyte interface polarization was found to be a predominant cause of this intrinsic nonlinearity and to be dependent on electrolytic ion concentration. We also measured and calculated coefficients of resistive and capacitive components of the observed nonlinearity. 相似文献
125.
Silicon - Al-Si based alloy matrix composites are now broadly utilized by the industrial sectors like automobile, structural, aerospace and more practical industrial applications due to its... 相似文献
126.
Pande Zhang Benxue Jiang Yiguang Jiang Ge Zhang Shuilin Chen Jintai Fan Long Zhang 《Journal of the American Ceramic Society》2017,100(11):5030-5037
Composite YAG/Nd:LuAG transparent ceramics were fabricated by a thermal bonding process. The spatial distribution of ions around the original bonding interface of the YAG/Nd:LuAG composite laser ceramic was investigated. Around the original bonding interface, Lu3+ and Y3+ ions were replaced with each other in dodecahedral symmetry sites. Results from X‐ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS) quantitative chemical analyses positively show that the distance of Y3+ ions diffused in the LuAG part is about 35 μm, while Lu3+ ions’ diffused distance in the YAG part is about 5 μm. This corresponds to the diffusion coefficient of Y3+ ions and Lu3+ ions (DY=2.43 ×10?10 cm2/s and DLu=0.56×10?10 cm2/s at 1750°C). The formation of YxLu(3?x)Al5O12 polycrystal in the bonding section explains the complete combination of LuAG and YAG without a bonding interface. Moreover, no diffusion phenomenon of Nd3+ ions was detected near the original bonding interface. 相似文献
127.
B. G. J. S. Sonneveld M. A. Keyzer P. Adegbola S. Pande 《Water Resources Management》2012,26(2):553-579
Climate change studies for West Africa tend to predict a reduced potential for farming that will affect the food security
situation of an already impoverished population. However, these studies largely ignore farmers’ adaptations and market adjustments
that mitigate predicted negative effects. The paper attempts to fill some of this gap through a spatially explicit evaluation
of the impact of climate change on farm income in the Oueme River Basin (ORB), Benin. The ORB is in many respects representative
for the middle belt of West Africa where the predominantly sparse occupation leaves potential for migration from more densely
populated areas. We apply a number of structural, spatially explicit relationships estimated for the whole territory of Benin
to simulate conditions in the ORB proper that are similar to those currently prevailing in the drier North, and the more humid
South. Our scenario results factor out for the main crops cultivated the constituent effects on yields, area, and revenue
per ton. We find that under average climate change conditions the current low yields are not reduced, provided that cropping
patterns are adjusted, while price increases partly compensate for the remaining adverse effects on farmer income. Consequently,
without any policy intervention, farm incomes remain relatively stable, albeit at low levels and with increased occurrence
of crop failures after extreme droughts. Scenario simulations show that there are also beneficial aspects that can, with adequate
interventions, even turn losses into gains. Main channel for improvement would be the reduction of fallow, which is particularly
promising because it requires few adjustments in prevailing farming practices, exploits the potential of uncultivated land
and improves the water use efficiency. It also enables the Basin's capacity to absorb future migrant flows from more severely
affected neighboring Sahelian areas. 相似文献
128.
RM. Senthamarai P. Devadas Manoharan D. Gobinath 《Construction and Building Materials》2011,25(5):2413-2419
Concrete which contains waste products as aggregate is called ‘Green’ concrete. Use of hazardous waste in concrete-making will lead to green environment and sustainable concrete technology and so such concrete can also be called as ‘Green’ concrete. Concrete made with ceramic electrical insulator waste as coarse aggregate shows good workability, compressive, tensile and flexural strengths and modulus of elasticity. Further, study of its durability will ensure greater reliability in its usage. Permeation characters are used widely to quantify durability properties of concrete. This paper presents an experimental investigation on the permeation characteristics [volume of voids and water absorption (ASTM C642-06), chloride penetration (ASTM C1202-10), and sorption] of concrete with ceramic electrical insulator waste coarse aggregate (hereafter it is called recycled aggregate concrete) of six different water–cement ratios in comparison with those of corresponding conventional concrete mixes. From the results it has been observed that there is no significant change in the basic trend of permeation characteristics of this recycled aggregate concrete when compared to the conventional concrete. This recycled aggregate concrete possesses higher permeation characteristic values than those of conventional concrete. These values decrease with decrease in water–cement ratio for both the recycled aggregate concrete and the conventional concrete. 相似文献
129.
The folding of a protein-like heteropolymer is studied by using direct simulation of a lattice model that folds rapidly to a well-defined "native" structure. The details of each molecular folding event depend on the random initial conformation as well as the random thermal fluctuations of the polymer. By analyzing the statistical properties of hundreds of folding events, a classical folding "pathway" for such a polymer is found that includes partially folded, on-pathway intermediates that are shown to be metastable equilibrium states of the polymer. These results are discussed in the context of the "classical" and "new" views of folding. 相似文献
130.
P Mooney M Sarmiento JM Bishop N Biswas NM Cason L Dauwe J Godfrey VP Kenney R Pemper E Rojek RC Ruchti WD Shephard G Ginther RM Edelstein CP Forsyth K Gamarnik AE Kreymer RJ Lipton JM McQuade DM Potter JS Russ L Spiegel DE Johnson D Buchholz LM Cremaldi SW Delchamps HS Mao JL Rosen W Sakumoto RA Schluter SB Sontz C Winter 《Canadian Metallurgical Quarterly》1989,39(9):2494-2498