Renal R2 chemoreceptor activity is attenuated after back heating in the rat

The aim of the present study was to determine the afferent connections of the nucleus accumbens in snakes, in particular its catecholaminergic input. For that purpose, in vitro and in vivo applications of retrograde tracers in the nucleus accumbens of Elaphe guttata were combined with tyrosine hydroxylase (TH) immunohistochemistry. Both techniques revealed telencephalic inputs to the nucleus accumbens originating from the diagonal band of Broca, ventral pallidum, amygdaloid complex, and dorsal cortex. Major diencephalic inputs arise from the dorsomedial thalamic nucleus and the hypothalamus. In the brainstem, a few retrogradely labeled cells were observed in the raphe nucleus and the locus coeruleus. Considerably more cells were found in the midbrain tegmentum. Within the confines of the locus coeruleus and, in particular, the midbrain tegmentum, retrogradely labeled cells stained also for TH suggesting that those areas constitute the major catecholaminergic input to the nucleus accumbens of snakes. The experimental approach used in the present study, in particular the in vitro technique, seems to be very suited for studying the development of basal ganglia organization of reptiles in the near future.     

NMR structure and mutagenesis of the FADD (Mort1) death-effector domain

When activated, membrane-bound receptors for Fas and tumour-necrosis factor initiate programmed cell death by recruiting the death domain of the adaptor protein FADD to the membrane. FADD then activates caspase 8 (also known as FLICE or MACH) through an interaction between the death-effector domains of FADD and caspase 8. This ultimately leads to the apoptotic response. Death-effector domains and homologous protein modules known as caspase-recruitment domains have been found in several proteins and are important regulators of caspase (FLICE) activity and of apoptosis. Here we describe the solution structure of a soluble, biologically active mutant of the FADD death-effector domain. The structure consists of six antiparallel, amphipathic alpha-helices and resembles the overall fold of the death domains of Fas and p75. Despite this structural similarity, mutations that inhibit protein-protein interactions involving the Fas death domain have no effect when introduced into the FADD death-effector domain. Instead, a hydrophobic region of the FADD death-effector domain that is not present in the death domains is vital for binding to FLICE and for apoptotic activity.     

The complexity of oblivious plans for orienting and distinguishing polygonal parts

In the problem ofparts feeding we are given a class of feasible operations for reorienting a part, and we are asked to find a fixed sequence of these operations which is guaranteed to bring the part into a known goal orientation from any possible initial orientation. Goldberg addressed this problem in [2], and showed that, for planar polygonal parts, there is always a sequence of simple operations which can be performed by a simple parallel-jaw gripper, which is guaranteed to orient the part (up to symmetry) without the use of any sensor information; he also conjectured thatO(n) steps are sufficient.In this paper we prove Goldberg's conjecture by explicitly constructing plans of at most2n – 1 steps for orienting polygonal parts in this model. We also give a lower bound on the number of steps required for such plans to show that this upper bound is tight.Finally, we extend these results to the problem ofdistinguishing among a finite set of parts using minimal sensing. Specifically, we assume that we are given a set of known polygonal parts, and a parallel-jaw gripper able to sense the distance between its jaws upon closure. We construct a simple oblivious plan of linear complexity which, when presented with a polygonal part, determines the index of this part.This research was supported in part by the NSF under Grant CCR-9207422, and by a Zumberge Fellowship. A preliminary version of this paper appeared in theProceedings of the Fourth Canadian Conference on Computational Geometry [1].     

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本文根据四川天然气产能建设多年的实践,分析了产能建设的特点和存在问题,着重强调了当前搞好产能建设应注意的几个问题,供决策和工作参考。     

糖化酶制剂辐照性能研究

研究了工业糖化酶制剂经辐照处理后各项性能的变化。结果表明,经2kGy以下剂量的γ射线处理后,可提高其贮存稳定性,改善卫生品质,不影响其正常使用。     

Observation of atomic steps on CaCO3 crystal surface

By using scanning polarization force microscopy,the deliquescence process and the atomic steps on the cleavage surface of CaCO3 in air were studied in situ.Under an exposure to medium umidity(-57%),the sloiw step movement has been observed.     

Occlusion of large atrial septal defects with a centering buttoned device: early clinical experience

A feasibility clinical study was conducted for the transcatheter occlusion of large ostium secundum atrial septal defects with the centering buttoned device. The centering buttoned device is a modification of the regular buttoned device in which a centering counter-occluder is sutured at the central 40% portion of the occluder. During centering it is stretched, forming a parachute-shaped structure and pulling the occluder over the center of the defect. During buttoning, the counter-occluder forms a double figure eight, opposing the right atrial side of the atrial septum. Occlusion was performed in 12 patients aged 6 to 56 years. All had been rejected for transcatheter occlusion by the regular buttoned device, because of either their defect size or the lack of adequate septal rim. The defect size varied between 23 and 31 mm, and the device size varied between 45 and 60 mm. Nine had immediate effective occlusions of their defects and three residual shunts. One patient with unbuttoning had hemolysis at 2 weeks and underwent surgery. Early results of the transcatheter occlusion of large atrial septal defects are promising, and larger clinical trials are justified.     

Relative contribution of endothelial cell and polymorphonuclear neutrophil activation in their interactions in systemic inflammatory response syndrome

OBJECTIVE: To examine the relative contribution of polymorphonuclear neutrophil (PMN) vs endothelial cell (EC) activation on the adherence and subsequent killing of ECs by PMNs. DESIGN: In vitro comparative studies of PMN-EC adherence and cytotoxicity. SETTING: Research laboratory and the surgical intensive care unit of a tertiary-level university hospital. PATIENTS: Patients with systemic inflammatory response syndrome admitted to the surgical intensive care unit and hospitalized preoperative noninfected surgical patients. INTERVENTION: None. METHODS: Polymorphonuclear neutrophils were isolated from 21 healthy volunteers, 22 preoperative patients, and 30 patients from the surgical intensive care unit with systemic inflammatory response syndrome. The PMNs were activated with lipopolysaccharide, 100 ng/mL (Escherichia coli 0111:b4), for 40 minutes at 37 degrees C before the adherence and cytotoxicity assays. Human umbilical vein endothelial monolayers were stimulated with tumor necrosis factor alpha, 25 ng/mL, and interleukin 1 beta, 15 U/mL, for 3 hours. The PMNs or EC cells were labeled with sodium chromate Cr 51 and used in a standard adherence or killing assay as required. RESULTS: Control and preoperative patient PMN treatment with lipopolysaccharide produced a modest increase in adherence. The PMNs from patients with systemic inflammatory response syndrome showed moderately increased human umbilical vein endothelial cell adherence, and this could not be augmented further with lipopolysaccharide stimulation. There was a marked increase in PMN adherence to EC after EC activation in all study groups (P < .001). Similar to the adherence data, human umbilical vein endothelial cell cytotoxicity was significantly increased in all groups after human umbilical vein endothelial cell activation (P < .01) but not after PMN stimulation with lipopolysaccharide. CONCLUSION: These data suggest that stimulation of ECs is far more important in producing increased adherence and cytotoxicity of EC than PMN stimulation with lipopolysaccharide in all study groups. Therapeutic efforts in patients with systemic inflammatory response syndrome should be focused on the EC.     

二元光栅照明研究

采用部分相干成象理论对二元光机照明进行了较为详细的研究。分析了二元光栅照明对分辨力，焦，照明能量和照明均匀性的影响，并通过实验研究验证了二元光栅对分辨力和焦深有较大程度的提高，同时能量损失不大。     

WTG420铁路罐车用钢的组织结构和力学性能分析

分析了ＷＴＧ４２０铁路罐车用钢的组织结构和力学性能。提出了冶炼与轧制的技术关键，其一，添加稀土元素改善钢中夹杂物；其二，采用控轧控冷使铁素体晶粒细化。