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1.
Axons of primary olfactory neurons are intimately associated with olfactory ensheathing cells (OECs) from the olfactory epithelium until the final targeting of axons within the olfactory bulb. However, little is understood about the nature and role of interactions between OECs and axons during development of the olfactory nerve pathway. We have used high resolution time-lapse microscopy to examine the growth and interactions of olfactory axons and OECs in vitro. Transgenic mice expressing fluorescent reporters in primary olfactory axons (OMP-ZsGreen) and ensheathing cells (S100ß-DsRed) enabled us to selectively analyse these cell types in explants of olfactory epithelium. We reveal here that rather than providing only a permissive substrate for axon growth, OECs play an active role in modulating the growth of pioneer olfactory axons. We show that the interactions between OECs and axons were dependent on lamellipodial waves on the shaft of OEC processes. The motility of OECs was mediated by GDNF, which stimulated cell migration and increased the apparent motility of the axons, whereas loss of OECs via laser ablation of the cells inhibited olfactory axon outgrowth. These results demonstrate that the migration of OECs strongly regulates the motility of axons and that stimulation of OEC motility enhances axon extension and growth cone activity.  相似文献   
2.
Allele-specific DNA methylation (ASM) is a hallmark of imprinted genes, but ASM in the larger nonimprinted fraction of the genome is less well characterized. Using methylation-sensitive SNP analysis (MSNP), we surveyed the human genome at 50K and 250K resolution, identifying ASM as recurrent genotype call conversions from heterozygosity to homozygosity when genomic DNAs were predigested with the methylation-sensitive restriction enzyme HpaII. Using independent assays, we confirmed ASM at 16 SNP-tagged loci distributed across various chromosomes. At 12 of these loci (75%), the ASM tracked strongly with the sequence of adjacent SNPs. Further analysis showed allele-specific mRNA expression at two loci from this methylation-based screen--the vanin and CYP2A6-CYP2A7 gene clusters--both implicated in traits of medical importance. This recurrent phenomenon of sequence-dependent ASM has practical implications for mapping and interpreting associations of noncoding SNPs and haplotypes with human phenotypes.  相似文献   
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Microstructures have profound effects on the hardness and strength of Cu-Cr alloys. The microstructures of a Cu-Cr alloy cast in a water-cooled copper mold were studied in the present work. The scanning electron microscopy (SEM) results show that there are the copper matrix saturated with chromium, spherical precipitates of chromium separated from liquid phase during cooling before the initiation of solidification, and a eutectic phase in grain boundary areas. To investigate the effect of age-hardening treatment on the microstructures and properties of the material, some samples were subsequently age-hardened in a salt bath and investigated by transmission electron microscopy (TEM). The results show that coherent precipitates with the diameter of 11 nm are detectable in the samples before and after the age-hardening stage. Of course, the volume fraction of coherent precipitates is higher after the aging process.  相似文献   
5.
This paper focuses on finding solutions to two important questions regarding making Iranian banks customer-oriented with the use of customer relationship management (CRM) concepts: What is a practical architecture for the CRM of a bank that can bring about benefits of CRM to the organization, and what is the method to achieve such architecture? This research uses an Action Research (AR) approach in one of the largest Iranian banks to achieve answers to the aforementioned questions. In brief, it concentrates on the AR cycle and its reflexes. In the plan stage, extended literature review, pioneer banks studies, and benchmarking provide a preliminary plan. Later, in the act stage this plan can be confirmed, extended, or customized based on more precise examination of the organization, managers and employees’ interviews, and customer opinion surveys. In the check stage, university and bank experts will review the plans and in the last stage of the cycle, reflected results, lessons, and experiences that help system design in the second bank will be discussed. The efficient method of achieving the CRM architecture (which in the beginning we had only general knowledge about) as well as the improvements that can be done based on experts’ opinions in order to receive more applicable results, are among the issues that will be discussed in this paper.  相似文献   
6.
Systemic Practice and Action Research - Considering the unfortunate intensification of the Non-performing loans in Iran`s credits system makes it vital to study the current system shortcomings....  相似文献   
7.
The increasing demands for medicinal leeches around the world has increased the need for new sources of leeches. To assess the feasibility of culturing a new medicinal leech species, growth, survival and reproduction of Hirudo orientalis was investigated under laboratory conditions (28°C; 9.5D:14.5L light regime; monthly feeding by sheep blood) from hatching until sexual maturity. Several interesting results emerged from this study. (1) The first copulation was observed in 5.5-month-old leeches and cocoon deposition started by six months. (2) Cocoon length and diameter did not differ significantly between six- and nine-month-old leeches, but the percentage of leeches depositing cocoons was significantly higher in the nine-month old group. (3) The growth curve was saltatory, similar to other sanguivorous species. The mean (±SE) wet weight of 6-month-old individuals was 4.70 (±0.86) g. (4) Weight gain rate decreased with increasing age. (5) Mortality only occurred in the one-, seven- and eight-month age groups at the rate of 5.7%, 23.1% and 14.3%, respectively.  相似文献   
8.
The aim of this study is to apply process mineralogy as a practical tool for further understanding and predicting the flotation kinetics of the copper sulfide minerals. The minerals' composition and association, grain distribution, and liberation within the ore samples were analyzed in the feed, concentrate, and the tailings of the flotation processes with two pulp densities of 25 wt% and 30 wt%. The major copper-bearing minerals identified by microscopic analysis of the concentrate samples included chalcopyrite(56.2 wt%), chalcocite(29.1 wt%),covellite(6.4 wt%), and bornite(4.7 wt%). Pyrite was the main sulfide gangue mineral(3.6 wt%) in the concentrates. A 95% degree of liberation with d_(80) 80 μm was obtained for chalcopyrite as the main copper mineral in the ore sample. The recovery rate and the grade in the concentrates were enhanced with increasing chalcopyrite particle size. Chalcopyrite particles with a d_(80) of approximately 100 μm were recovered at the early stages of the flotation process. The kinetic studies showed that the kinetic second-order rectangular distribution model perfectly fit the flotation test data. Characterization of the kinetic parameters indicated that the optimum granulation distribution range for achieving a maximum flotation rate for chalcopyrite particles was between the sizes 50 and 55 μm.  相似文献   
9.
提出了一种形式方法用于验证TLM-2.0的设计方案.该方法中TLM-2.0设计方案将被转换成定时自动机形式模型.定义若干种属性,验证将根据这些属性执行,并引入一种模拟事务级设计方案差错的故障模型来评估这些属性.然后这些属性通过使用形式UPPAAL验证工具在系统的定时自动机表示上针对这些故障被验证.最后通过一个实例研究说明该方法的有效性.  相似文献   
10.
Systemic Practice and Action Research - Child labour has become an ever growing social problem in developing countries like Iran. This study presents a strategy for solving this problem regarding...  相似文献   
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