Magnocellular axons in passage through the median eminence release vasopressin

Vasopressin (arginine vasopressin, AVP) is present in two types of nerve fibres in the median eminence (ME). First, it is found in nerve terminals that originate in the parvicellular neurones of the hypothalamic paraventricular nucleus (PVN) and abut on the pericapillary space surrounding the fenestrated capillaries of the primary pituitary portal plexus in the external zone (EZ) of the ME. These neurones also synthesize corticotropin-releasing factor (CRF), which acts synergetically with vasopressin to stimulate release of adrenocorticotropin (ACTH) from the pituitary gland (see ref. 7). Second, vasopressinergic axons of the magnocellular neurosecretory system pass through the internal zone (IZ) of the ME to terminate in the neurohaemal contact zone of the neurohypophysis. The involvement of vasopressinergic magnocellular neurones in the control of ACTH secretion is much debated. Of particular interest in this context is the origin of the vasopressin found in pituitary portal blood. Although it has been demonstrated that vasopressin and CRF are present in the same neurosecretory granules of EZ fibres, parallel determinations of vasopressin and CRF in pituitary portal blood have shown alterations of the concentration of vasopressin without a concomitant change in that of CRF. Such a dissociation suggests that either differential release of vasopressin and CRF can occur from a single population of nerve endings, or there are fibres in the pituitary-stalk ME which release vasopressin but not CRF. Here we present evidence for the latter. Our results indicate that stimuli causing depolarization of the axonal membrane in vitro elicit release of vasopressin from nerve fibres in the external and internal zones of the ME.     

Co-localization of corticotropin-releasing factor and vasopressin in median eminence neurosecretory vesicles

Vasopressin (VP) potentiates the effect of corticotropin-releasing factor (CRF) on the secretion of adrenocorticotropic hormone (ACTH) from anterior pituitary cells in vitro, and both CRF and VP have been found in portal blood. These data support the hypothesis that VP acts synergistically with CRF to cause the secretion of ACTH in vivo but the origin of the CRF and VP, and the physiology of their release, have not been precisely defined. Parvocellular cell bodies in the paraventricular nucleus (PVN) which project to the external zone of the median eminence can be stained for both CRF and VP after adrenalectomy, and there is light microscopic immunocytochemical evidence that neurophysin (NP) may be located within some of the CRF-containing axons. Electron microscopic immunocytochemical studies have demonstrated the presence of CRF, VP and its 'carrier' protein, VP-associated neurophysin (NP-VP) in 100-nm neurosecretory vesicles (NSVs) in axons terminating near the portal capillary plexus in the external zone of the median eminence. If these peptides are extensively co-localized in the same NSVs in the median eminence, then coordinate secretion of CRF and VP in vivo is obligatory, at least in some physiological circumstances. We demonstrate in this report, using post-embedding electron microscopic immunocytochemistry on serial ultrathin sections, that CRF, VP and NP-VP are contained not only in the same axons and terminals, but in the same 100-nm NSVs in the median eminence of both normal and adrenalectomized rats. In addition, in the normal rat median eminence 44% of the CRF-positive axons and terminals stained strongly for VP and NP-VP, whereas in the adrenalectomized rat virtually all the CRF-positive structures in the median eminence showed strong staining for VP and NP-VP, indicating a transformation of one subpopulation of CRF-positive axons and terminals by adrenalectomy.     

高速逆流色谱系统中的信号的计算机采集和控制

结合电子测量技术和计算机控制技术，设计了一种高速逆流色谱的信号采集和控制系统．在实现流出组分吸光度信号的采集、处理、谱图显示的同时，提供按等体积方式对组分进行收集的功能．介绍了该系统工作的基本原理、系统的硬件组成和软件设计．     

高速逆流色谱制备雷酚内酯异构体的研究

以选定的溶剂体系为基础,研究温度、转速对高速逆流色谱技术分离制备雷酚内酯异构体工艺的影响。研究结果表明,在选定的溶剂体系(正己烷∶乙酸乙酯∶甲醇∶水=2∶3∶3∶2,V/V/V/V)下,流动相流速为2.0 mL/min时,正向洗脱,分离较佳的恒温水浴循环水温度为25.0℃、转速为800 r/min,此时管柱内固定相的保留率为60.0%,管路工作压力为0.15 MPa。     

高速逆流色谱法分离珠子草中的木脂素

为克服采用传统方法分离木脂素的不足,采用高速逆流色谱法对珠子草中的木脂素进行分离,得到3个木脂素,通过红外光谱（ IR）、质谱（ MS）、核磁共振（ NMR）等方法鉴定为珠子草素（ niranthin）、叶下珠次素（hypophyllanthin）和叶下珠脂素（phyllanthin）。分离溶剂体系为正己烷/乙酸乙酯/甲醇/水（3/2/3/2,V/V）,下相为流动相,流速为2 mL/min,转速为正转800 r/min,温度为25℃。实验结果为木脂素的分离提供了一条有效的途径。     

高速逆流法分离纯化五味子中的五味子酚

95%乙醇提取五味子种子的粗提物,经过硅胶分离后的1g粗品用高速逆流色谱首次分离得到122mg纯度为99.9%的五味子酚,结构经ESI-MS,MS/MS鉴定。同时分离得到86mg纯度为98%的五味子甲素、93mg纯度为97%的五味子乙素和114mg纯度为99%的五味子酯甲。两相溶剂系统确定为正已烷-甲醇-水（体积比为7:6:1）的三元溶剂系统,上相为固定相,下相为流动相,转速为800r/min,流速为2.0mL/min。     

用虚拟多管模型研究填料塔气液逆流停留时间分布

对填料塔中的气液逆流过程,用虚拟气液固圆柱体建立了多管流动模型,得到了充分发展段和进口过渡段的速度分布和一定管长下的液相停留时间分布,进而求得液相平均停留时间和持液量的表达式及模型参数,并用实验进行了验证。该模型反映了气液逆流过程本质,简化了过程,适用于液相层流的情况。     

用连续逆流式超临界双塔浓缩和精制维生素K1

文中研究了用连续逆流式超临界双塔浓缩和精制维生素K₁的工艺方法。第一塔压力18～24MPa，温度35～50℃；第二塔压力8～11MPa，温度40～60℃；CO₂与原料质量流量比由37.5到70。产品为清亮黄色油状液体，维生素K1的质量分数可达97.24%。     

基于自适应中值滤波器和TV修复的椒盐噪声去除

提出一种两步式椒盐噪声去除方法．第一步利用自适应中值滤波器来识别出被噪声污染的候选点;第二步利用一种边缘保持技术（全变差图像修复）来恢复出被噪声污染的点．由于椒盐噪声点的灰度值和原始像素灰度独立,所以在采用恢复技术时不使用噪声点自身的灰度信息．在噪声率不很高的情况下,这种方法可以获得比现有最好方法更高的信噪比;当噪声率高达70％以上时,该方法的信噪比与现有方法非常接近,但是主观视觉效果（例如边缘保持能力）更佳．     

梯度在多元函数上的应用

本文研究了多元函数梯度在多元函数连续性和极值上几个应用.     

逆流色谱溶剂体系选择的溶液理论模型

从溶液理论出发，建立一个预测和选择逆流色谱溶剂体系的模型，预测了影响分离效果的两相分相情况、两相相比、密度、界面张力等因素，并估算了溶质的分离情况。用文献值和实验值对预测结果进行了检验，结果表明，各参数的预测结果较好，溶质分离情况的估算可指导确定溶质的出峰顺序。     

Alterations in cecal microbiota of Jinhua piglets fostered by a Yorkshire sow

Gut microbiota health and diseases. Several play important roles in host factors, in particular antibiot- ics, affect the gut microbiota of pigs. Cross-fostering has been applied as a regular practice to equalize litter size, reduce pre-weaning mortality and increase body weight. However, the effect of cross-fostering on cecal microbiota is unclear. In this study, we fostered three Jinhua pigs to a Yorkshire sow. The fostered Jinhua piglets grew signifi- cantly faster than their biological siblings. To explore whether the cecal microbiota of piglets will alter during fostering, we characterized the cecal microbiota of allpiglets by examining the V3 hypervariable region ot 165 rDNA. We observed altered cecal microbiota in these piglets using the Illumina HiSeq 2000 platform, and this was accompanied with an increase in growth rate after fostering. The relative abundance of Bacteroidetes in the fostered Jinhua piglets was decreased compared with their biological siblings, although still higher in comparison with their new littermates. Beta-diversity analysis also showed that the cecal microbiota of the adopted Jinhua piglets differed from their biological siblings with a shift toward their step-siblings. Our data show that cecal microbiota of piglets were altered after cross-fostering while the growth rate increased.     

Head rotation and sound image localization in the median plane

The effect of head rotation on median plane sound source (or image) localization is studied. It is suggested that, at low frequency, the change of interaural time difference (ITD) caused by head rotation supplies information for determining sound source direction in the median plane. Based on the suggestion, the summed sound image Ioealization equations for multiple loudspeakers arranged in the median plane are derived. Especially, for a pair of loudspeakers arranged front-back symmetrically in the median plane, the localization equations are similar to that of stereophonic sound in horizontal plane. A sound image localization experiment was carried out to prove the theoretical analysis. The results of this paper are not only available to virtual spatial auditory, but also supply a quantitative validation of the hypothesis that head rotation is a cue for sound source localization in the median plane at low frequency.     

目标检测中的快速中值滤波法

在简要描述条带式CCD(Charge Coupled Device)弹道相机测试系统中的计算机软件处理子系统的基础上,针对在图像处理过程中,中值滤波排序工作量多、速度慢、非实时性的缺点,提出了一种快速中值滤波法.其主要特点是充分利用相邻两个中值滤波窗口内信号数据的相关性,通过移出和移入一列像素,而保留其左边界和上边界窗口内的排序信息;仅对新移入的像素进行排序的方法,完成中值滤波处理.使传统算法的复杂度由O(D4)下降到O(D2),大大提高了运算速度.将此方法应用到测试系统中,取得了很好的效果,实现了系统实时性要求.