贮液池工程质量保障措施的探讨

分析了影响贮液池工程质量的因素,进而从设计方面、施工方面、施工工艺方面提出了保障贮液池工程质量的措施.     

一种石化行业专用冷水机组的设计

以一种节能防腐防爆石化行业专用冷水机组的设计过程为例,介绍了机组在系统设计方面、防腐方面、防爆方面以及控制方面的特点和设计选型的相关情况。     

高职院校法律专业实践教学方法初探

我国的很多高职院校开展了法律专业,并且随着我国法治方面的发展也取得了很大的进步,但是在法律专业实践教学方面做的还有些欠缺,还是借助于传统的教学方法和课程设置,没有注重到高职院校学生操作实践能力的培养,考虑不到社会方面的实际需求。这就需要加强学生的实践教学,因此从以下几个方面分析了高职院校法律专业实践教学方法。     

公交车站智能信息发布系统的设计

本文介绍基于RFID技术设计了一种可以安装在公交车站的电子信息发布系统,主要包含硬件设计和嵌入式软件设计两个方面;硬件方面主要围绕整个的功能需求、模块构架、器件方案等方面进行阐述,而嵌入式软件方面主要针对指站台控制器的设计进行阐述,并总结了此系统的一些优点。     

基于Pro/E的直齿圆柱齿轮的CAD/CAM/CAE一体化技术研究

主要研究了在Pro/E环境下直齿圆柱齿轮的CAD/CAM/CAE一体化技术.在CAD方面,分析了Pro/E实体建模的核心思想,并进行了齿轮的实体建模.在CAE方面,进行了齿轮的结构静力学分析.在CAM方面,对齿轮进行了数控加工仿真,并生成了NC代码.     

电能计量的无线采集与监视系统优化探析

在对电能计量采集与监视系统的应用现状、结构组成及不足之处进行分析的基础上,着重从通信协议、数据传输、人机界面、电源系统4个方面进行了优化改进,有针对性地解决了这4个方面的问题,可为此方面的应用研究提供参考。     

基于Linux嵌入式的电源管理的研究

文章从硬件及软件方面介绍了TagMaster AB公司的RFID手持阅读器电源管理的设计.在硬件设计方面,手持阅读器采用了Atmel公司的AT91RM9200高性能低功耗微控制器,并利用芯片的电源管理模块控制外设;在软件方面,采用了多种电源管理策略,实现了与外接设备特性相符的电源管理函数.经使用测试,手持阅读器功耗得到了大幅度的下降.     

双壳贝类消化生理的研究进展

本文总结了近些年来双壳贝类组织学和组织化学方面及双壳贝类消化酶方面的研究。组织学方面总结了消化道和消化腺的结构,组织化学总结了消化道和消化腺中富含的各种物质和消化酶。目前,双壳贝类消化生理的研究仍有很大的空白,研究前景相当广阔。     

配电电缆截面选择

文章对配电电缆设计选择载流量截面、投资费用与选择方案等方面均进行了有关经济技术的分析,提出了可行的补偿年限法,在经济方面取得了显著效果.     

顶高可调式交叉滚轮轴承六方面偏心轴的设计

分析了小滚轮外径顶高可调式交叉滚轮轴承中两端六方面偏心轴的设计方法,导出了六方面中垂线与滚动体内切圆水平轴线x、垂直轴线y的不同位置和小滚轮顶高增高量之间的关系式,并得出了六方面中垂线与x,y轴线最合适的夹角。     

Histochemical and ultrahistochemical localization of heavy metals in calf organs

Cadmium, zinc, selenium, and copper were administered, singly or in combination, orally or subcutaneously. Experiment I included 32 calves of both sexes; six received Cd (two groups), Zn, Cd, and Zn, and Cd and Se (two groups) and one group was a control. In Experiment II (21 bulls), three were given Cd, Cd, and Cu, and Cd and Zn, respectively, and one group was a control. For light microscopy, in Experiment I the highest amounts of silver granules were present in the samples of liver, small intestine, and vesicular gland of all the exposed groups; in Experiment II the most affected organs were liver, kidney, and small intestine. For electron microscopy, in Experiment I, after administration of Cd and Zn, the highest amounts of granules were seen in the cytoplasm of hepatocytes and cells of the proximal and distal renal tubules and the lowest amounts were found in glandular cells of the pancreas. Administration of Cd and Se resulted in the presence of large numbers of granules in the nuclei and nucleoli of spermatogonies. In Experiment II, ingestion of Cd and Zn in feed led to the appearance of highest amounts of granules in the nucleoli, nuclei, and cytoplasm of cells in testes, kidneys, and pancreas. Following Cd intake, the highest accumulation of granules was observed in the nucleoli of hepatocytes and cells of the proximal and distal renal tubules. Combined Cd and Cu produced the highest number of granules in cells of the proximal and distal renal tubules and in the nucleoli and nuclei of germinal epithelium.     

Immunolocalization of S100-like protein in the brain of an emerging model organism: Nothobranchius furzeri

The S100 protein in nervous tissue appears to play important roles in regulating neuronal differentiation, glial proliferation, plasticity, development, axonal growth, and in neurogenetic processes. In fish, the adult neurogenic activity is much higher than in mammals. In this study, the localization of S100 protein was investigated in the brain of annual teleost fish, Nothobranchius furzeri, which is an emerging model organism for aging research. By immunohistochemical techniques, S100 immunoreactivity (IR) was detected in glial cells, small neurons, and fibers throughout all regions of central nervous system (CNS) with different pattern of distribution. In the telencephalon, S100 IR was seen in the olfactory bulbs and in different areas of the telencephalic hemispheres. In the diencephalon, S100 positivity was observed in the habenular nuclei of the epithalamus, in the cortical thalamic nucleus, in the dorsal, ventral and caudal portions, the latter with the posterior recessus nucleus, and in the diffuse inferior lobe of the hypothalamus, along the diencephalic ventricle and in the dorsal optic tract. In the mesencephalon, S100 IR was observed in the longitudinal tori, in the optic tectum, and along the mesencephalic ventricle. In the rhombencephalon, S100 IR was shown in valvula and body of the cerebellum, and in some nuclei of the medulla oblongata. The results suggest that S100 may play a key role in the maintenance of the CNS and in neurogenesis processes in the adulthood.     

中国部分典型地区气溶胶光学特性观测

利用DTF型太阳光度计在我国几个典型城市地区较长期观测得到的资料,分析了不同地区气溶胶光学厚度日变化和季节变化特征,得到了各地区观测期间日均值、月均值和季节值的变化.结果显示,观测期间丽江地区气溶胶光学厚度最小,大气较洁净,大气中以细粒子为主;其次是张北;喀什和合肥地区气溶胶光学厚度都较大,但喀什、张北多以粗粒子为主,合肥多以细粒子为主.各地区都在春季气溶胶光学厚度较大,冬季最小.喀什的气溶胶光学厚度值多集中在0.15到0.7之间,张北多集中在0.08到0.4之间,合肥多集中在0.2到0.75之间,丽江多集中在0.01到0.1之间.各地区气溶胶光学厚度和(A)ngstr(o)m波长指数频率分布基本呈高斯分布,气溶胶光学厚度峰值分布由高到低依次为合肥、喀什、张北、丽江,(A)ngstr(o)m波长指数由高到低依次为丽江、合肥、张北、喀什.     

Sinusoidal endothelial cells of the liver: Fine structure and function in relation to age

Liver endothelial cells form a continuous lining of the liver capillaries, or sinusoids, separating parenchymal cells and fat-storing cells from sinusoidal blood. Liver sinusoidal endothelial cells differ in fine structure from endothelial cells lining larger blood vessels and from other capillary endothelia in that they lack a distinct basement membrane and also contain open pores, or fenestrae, in the thin cytoplasmic projections which constitute the sinusoidal wall. This distinctive morphology supports the protective role played by liver endothelium, the cells forming a general barrier against pathogenic agents and serving as a selective sieve for substances passing from the blood to parenchymal and fat-storing cells, and vice versa. Sinusoidal endothelial cells, furthermore, significantly participate in the metabolic and clearance functions of the liver. They have been shown to be involved in the endocytosis and metabolism of a wide range of macromolecules, including glycoproteins, lipoproteins, extracellular matrix components, and inert colloids, establishing endothelial cells as a vital link in the complex network of cellular interactions and cooperation in the liver. Fine structural studies in combination with the development of cell isolation and culture techniques from both experimental animal and human liver have greatly contributed to the elucidation of these endothelial cell functions. Morphological and biochemical investigations have both revealed little changes with age except for an accumulation of iron ferritin and a decrease in the activities of glucose-6-phosphatase, Mg-ATPase, and in glucagon-stimulated adenylcyclase. Future studies are likely to disclose more fully the role of sinusoidal endothelial cells in the regulation of liver hemodynamics, in liver metabolism and blood clearance, in the maintenance of hepatic structure, in the pathogenesis of various liver diseases, and in the aging process in the liver.     

TRPV4 in the sensory organs of adult zebrafish

TRPV4 is a nonselective cation channel that belongs to the vanilloid (V) subfamily of transient receptor potential (TRP) ion channels. While TRP channels have been found to be involved in sensing temperature, light, pressure, and chemical stimuli, TPRV4 is believed to be primarily a mechanosensor although it can also respond to warm temperatures, acidic pH, and several chemical compounds. In zebrafish, the expression of trpv4 has been studied during embryonic development, whereas its pattern of TPRV4 expression during the adult life has not been thoroughly analyzed. In this study, the occurrence of TRPV4 was addressed in the zebrafish sensory organs at the mRNA (RT-PCR) and protein (Westernblot) levels. Once the occurrence of TRPV4 was demonstrated, the TRPV4 positive cells were identified by using immunohistochemistry. TPRV4 was detected in mantle and sensory cells of neuromasts, in a subpopulation of hair sensory cells in the macula and in the cristae ampullaris of the inner ear, in sensory cells in the taste buds, in crypt neurons and ciliated sensory neurons of the olfactory epithelium, and in cells of the retina. These results demonstrate the presence of TRPV4 in all sensory organs of adult zebrafish and are consistent with the multiple physiological functions suspected for TRPV4 in mammals (mechanosensation, hearing, and temperature sensing), but furthermore suggest potential roles in olfaction and vision in zebrafish.     

Immunohistochemistry of neuronal nitric oxide synthase and protein nitration in the striatum of the aged rat

To ascertain the possible implications of the nitric oxide (NO*) producing system in striatal senescence, and by using immunohistochemistry and image-processing approaches, we describe the presence of the enzyme nitric oxide synthase (NOS), the NADPH-diaphorase (NADPH-d) histochemical marker, and nitrotyrosine-derived complexes (N-Tyr) in the striatum of adult and aged rats. The results showed neuronal NOS immunoreactive (nNOS-IR) aspiny medium-sized neurons and nervous fibres in both age groups, with no variation in the percentage of immunoreactive area but a significant decrease in the intensity and in the number of somata with age, which were not related to the observed increase with age of the striatal bundles of the white matter. In addition, NADPH-d activity was detected in neurons with morphology similar to that of the nNOS-IR cells; a decrease in the percentage of area per field and in the number of cells, but an increase in the intensity of staining for the NADPH-d histochemical marker, were detected with age. The number of neuronal NADPH-d somata was higher than for the nNOS-IR ones in both age groups. Moreover, N-Tyr-IR complexes were observed in cells (neurons and glia) and fibres, with a significant increase in the percentage of the area of immunoreaction, related to the increase of white matter, but a decrease in intensity for the aged group. On the other hand, we did not detect the inducible isoform (iNOS) either in adult or in aged rats. Taken together, these results support the contention that NADPH-d staining is not such an unambiguous marker for nNOS, and that increased protein nitration may participate in striatal aging.     

Distribution of sex steroid hormone receptors in the avian brain: functional implications for neural sex differences and sexual behaviors

Developmental and seasonal changes in the production of androgens, estrogens, and progestins seem to control sex-specific differentiation and seasonal changes in appetitive and consummatory sexual behaviors of birds. This results in profound sex differences in the quality (sex-specific) or quantity (sex-typical) of behaviors such as courtship, territoriality, or copulation. Steroids affect the brain by binding to intracellularly located receptors. The same brain areas express androgen, estrogen, and progesterone receptors in male and female brains. Sex differences in these genetically determined patterns occur in the size of neuron populations that intrinsically express sex steroid receptors. Further permanent sex differences are subsequent to degenerative fates of receptor expressing neuron populations during ontogeny. Transient sex differences in receptor expression appear to be due to area-specific up- and down-regulation of receptor levels, reflecting transient changes in the level of circulating steroids, changes in environmental conditions, or in the physiological status of the individuals. In particular, intrinsic sex differences in the expression pattern of sex steroid receptors and steroid-independent regulation of the expression level of these receptors in the brain are limiting mechanisms for gonad-dependent sexual development and activities.     

Application of elemental microanalysis to elucidate the role of spherites in the digestive gland of the helicid snail Chilostoma lefeburiana

In this case study we present an application of different analytical electron microscopic methods in biology, to elucidate their usefulness in such investigations. Using analytical electron microscopy, spherites in the digestive gland cells of the helicid snail Chilostoma lefeburiana were examined at three stages: just before the non-feeding period of over-wintering in November, in the middle of over-wintering in February and at its end in March. A detailed characterization of changes in the elemental composition of the spherites was characterized by a combination of transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDXS), electron energy-loss spectroscopy (EELS) and energy filtering TEM (EFTEM). During over-wintering, the spherites passed the following changes. Before over-wintering in November, they consisted of striking concentric layers of electron-dense and electron-lucent zones, while in February and March they showed clear empty zones between materials of different electron density. In November spherites, C, O, Ca, P, Cl, Fe, Si, Na, K, Mg and S were detected, whereas in February ones C, O, N, Cl, Si and S were found and only C, O, N, Si and Cl were detected in March spherites. It is suggested that the elements missing in February and March were used in different physiological processes during over-wintering, like (1) the maintenance of the appropriate elemental composition of the internal environment, (2) accumulation of non-toxic waste materials that cannot be metabolized and (3) avoiding potential intoxication by contamination with toxic metals.     

Early changes induced by short-term low-dose cadmium exposure in rat ventral and dorsolateral prostates

Prostate cancer (PCa) is the most commonly diagnosed cancer in men. The etiology of PCa in humans is multifactorial and includes age, ethnicity, environmental factors, and other unknown causes. Epidemiological and experimental evidence has shown that cadmium is associated with PCa both in humans and rodents. This metal can act as an endocrine disruptor during prostate development, and it induces prostate lesions late in life. In this study, we investigated the effects of low-dose cadmium on rat prostate morphology during puberty. Two-month-old male Wistar rats were randomized into two experimental groups: cadmium-treated and control. The ventral and dorsolateral prostates were dissected, weighed, and immunohistochemically stained with specific antibodies against Ki-67 and the androgen receptor (AR). The concentration of cadmium was measured in the blood and prostate, and testosterone concentration was measured from the plasma. Our results show that cadmium concentration was increased in both the blood and the prostate of cadmium-treated rats, but there were no changes in the prostatic weight, epithelial cell height, or testosterone levels. However, AR immunostaining and epithelial cell proliferation (Ki-67 index) were increased in both prostates with an increase in apoptosis only in the dorsal lobe. Furthermore, atypical hyperplasic proliferative lesions were found in the dorsolateral lobe after cadmium exposure. Cadmium treatment reduced collagen fiber absolute volume in both prostates. Thus, low-doses of cadmium, even for a short period of time, can interfere with prostate epithelium-stroma homeostasis, and this disruption might be an important factor in the onset of prostate lesions late in life.     

原子吸收分光光度法在环境分析领域中的应用

原子吸收分光光度法是国内外环境分析中最常见的方法之一,本文介绍了原子吸收分光光度法在环境分析中的应用,对美国ＥＰＡ、日本ＪＩＳ和我国现行的标准法系列和统一方法进行了比较,还报道了ＧＦＡＡＳ测定的样品消解中,可能由于用水及酸类引起的沾污问题,同时对国外ＧＦＡＳＳ法直接测定固体环境试样进行了报道,环境形态分析是ＡＡＳ法的主要应用领域,且该技术在国内外发展很快,以Ａｓ、Ｐｂ、Ｓｎ的形态分析为重点,介绍了ＧＣ－ＡＡＳ、ＨＰＬＣ－ＡＡＳ、ＩＣ－ＡＥＳ在形态分析中的应用,同时,对于使用不同的固体样品处理方法,使用ＡＡＳ测定定重金属也进行了介绍,本文引用至１９９９年国内外文献４４篇。