Parathyroid hormone (PTH) stimulates adrenocorticotropin release in AtT-20 cells stably expressing a common receptor for PTH and PTH-related peptide

Complementary DNA encoding a rat bone PTH/PTHrP receptor was stably expressed in the murine corticotroph cell line, AtT-20. Several clones, expressing variable numbers of PTH/PTHrP receptors, were developed. In contrast to the relatively low binding affinity (apparent Kd = 15 nM) observed in COS-7 cells transiently expressing the PTH/PTHrP receptor, all AtT-20 stable transfectants bound [Nle8,18,Tyr34]bPTH(1-34)NH2 (NlePTH) with an affinity that was indistinguishable from that observed in ROS 17/2.8 cells expressing native PTH/PTHrP receptors. Additionally, NlePTH dramatically increased cAMP accumulation and ACTH release in AtT-20 cells expressing the PTH/PTHrP receptor with an ED50 of 0.6 +/- 0.3 and 0.3 +/- 0.1 nM, respectively. The high binding affinity and the high efficacy of NlePTH in stimulating cAMP accumulation and ACTH release indicate that the PTH/PTHrP receptor is efficiently coupled to the intracellular signalling system responsible for stimulation of ACTH release in AtT-20 cells. No additivity of cAMP accumulation or of ACTH release was observed when these cells were treated with maximally active concentrations of both NlePTH and CRF. This suggests that the receptors for both of these hormones share the same intracellular effectors, and that intracellular signaling in AtT-20 cells is not compartmentalized. Additionally, the ability of NlePTH to stimulate ACTH release in AtT-20 cells, a function that is normally performed by CRF, demonstrates promiscuity between activated receptors and distal biological functions.     

开磷集团都匀氮肥厂造气废水治理

开磷集团都匀氮肥厂造气废水经沉淀捞渣,去除悬浮物后进入微涡流塔板澄清器中进一步澄清处理,经澄清后的水进入高效玻璃钢冷却塔冷却后,清水泵打入洗气塔内循环使用。     

工业机器人自适应逆模控制

本文提出一种关节型机器人的自适应逆模控制结构,采用机器人关节的等效线性系统的逆系统模型和满足可实现性条件的滤波器来构造相应的控制器,并由自适应机构在线建立和修改逆模的参数,使机器人的实际运行轨迹渐近地再现希望轨迹。仿真实验结果表明:采用本方案构造的控制系统响应速度快,跟随精度高、抗干扰能力强。此外,系统结构简单,易于实现。     

西方话语中的中国制造

在C C TV总部大楼的方案设计竞赛中,荷兰著名的大都会建筑事务所(O M A)获邀参加,和几十家境内外的建筑事务所进行角逐,在评委们的几经反复之后,最终库哈斯的方案胜出,这一结果对于很多人来说都是难以令人接受的,所以随之而来的便是铺天盖地的质疑之声,概括来说,公众对之的批评     

An analysis of BioHashing and its variants

As a result of the growing demand for accurate and reliable personal authentication, biometric recognition, a substitute for or complement to existing authentication technologies, has attracted considerable attention. It has recently been reported that, along with its variants, BioHashing, a new technique that combines biometric features and a tokenized (pseudo-) random number (TRN), has achieved perfect accuracy, having zero equal error rates (EER) for faces, fingerprints and palmprints. There are, however, anomalies in this approach. These are identified in this paper, in which we systematically analyze the details of the approach and conclude that the claim of having achieved a zero EER is based upon an impractical hidden assumption. We simulate the claimants’ experiments and find that it is not possible to achieve their reported performance without the hidden assumption and that, indeed, the results are worse than when using the biometric alone.     

新型炭复合材料吸附剂脱除汽油中硫化物的研究

制备了负载不同过渡金属离子（Ag^＋、Cu^2＋）的吸附剂Ag／Al2O3、Cu／Al2O3和Ag／SiO2，在固定床吸附脱硫装置上，考察了吸附剂对汽油模型化合物MGF-1（正庚烷中含噻吩硫760mg／L）的脱硫效果。结果表明，Ag／Al2O3具有较好的脱硫效果。将Al2O3在630℃下分别覆炭4，6，8h制得覆炭吸附剂，测定了覆炭吸附剂负载Ag^＋后对汽油模型化合物MGF-1和MGF-2的脱硫效果。结果表明，吸附剂覆炭后可明显提高吸附剂对硫化物的吸附选择性，当覆炭时间为6h时，吸附剂对硫化物的吸附选择性最好。     

快速一步法（ROSE法）提取DNA应用于RAPD—PCR扩增

对ＲＯＳＥ法的操作程序进行了进一步的简化，“一管一步”即可完成ＤＮＡ提取全过程，系统地与ＣＴＡＢ和ＳＤＳ法进行了比较，其提取过程明显比ＣＴＡＢ法、ＳＤＳ法简单，提取效率分别比ＣＴＡＢ、ＳＤＳ提高４倍和９倍，无污染物产生；与ＣＴＡＢ和ＳＤＳ法比分别节省费用约２００％和７００％。提取的ＤＮＡ能满足ＲＡＰＤ－ＰＣＲ研究的需要。因此，改良后的ＲＯＳＥ法可能是一种适合于ＤＮＡ提取自动化的方法，同时可能成为植     

Heterogeneity in intensive care units: fact or fiction?

Weight reduction, either by dietary or surgical means, is associated with prolongation of the heart rate corrected QT interval (QTc = QT/R-R0.5) and, on occasion, sudden death. Screening subjects with obesity before weight loss for prolonged QTc intervals is an accepted practice, although at present, there are no guidelines for whether subjects should be fasting before electrocardiogram (EKG) evaluation. The aim of this study was to test the hypothesis that EKG QTc interval duration is independent of meal ingestion. The hypothesis was tested in 11 healthy subjects who ingested a 500-kcal formula meal. A small decrease in absolute QT interval and a steady decline in R-R interval were observed for up to 60 minutes after formula ingestion. The QTc interval increased above baseline at 15 minutes (p < 0.007) after meal, a change that persisted for the 1-hour postmeal observation period. Spectral analysis of EKG R-R intervals (low-/high-frequency amplitude ratio) indicated a change in cardiac autonomic flow after meal ingestion. The QTc interval did not lengthen and R-R low-/high-frequency amplitude ratio remained unchanged in eight subjects evaluated in a similar manner but in whom isovolumic amounts of water replaced the meal. These observations suggest that (1) cardiac repolarization changes with fasting and feeding, (2) the QTc interval is influenced by meal intake, and (3) the autonomic nervous system may play a role in meal-related QTc changes. These findings have implications for the evaluation of patients with obesity before starting and during weight loss treatment.