稀土与L-酪氨酸甘氨酸三元固态配合物的合成与表征

在乙醇溶液中合成了四种稀土与 L-酪氨酸、甘氨酸的三元固态配合物 RE( Tyr) 1.5 ( Gly) 4 ( Cl O4) 3( RE=La3+、Ce3+、Gd3+、Y3+) ,并通过摩尔电导、热分析、红外光谱等进行了表征。     

H∞混合灵敏度控制在主汽压系统中的应用

主蒸汽压力是电厂热工过程控制中的重要参数,由于锅炉燃烧工况变化较大,主汽压对象模型具有不确定性,常规控制方法很难得到预期的控制效果。为提高系统控制品质,提出了主汽压系统的H∞混合灵敏度设计方法,给出了选择加权函数的具体方法,采用MATLAB软件进行仿真计算,得到H∞最优控制器。仿真结果表明,在对象模型参数发生较大变化时,与常规PID调节方法相比,H∞最优控制器能使主汽压控制系统具有良好的鲁棒稳定性和动态性能。     

Sympathetic response to stimulation of the pontine A5 region in conscious rabbits

OBJECT: This study is a retrospective analysis of clinical data obtained in 28 patients affected by obstructive hydrocephalus who presented with signs of midbrain dysfunction during episodes of shunt malfunction. METHODS: All patients presented with an upward gaze palsy, sometimes associated with other signs of oculomotor dysfunction. In seven cases the ocular signs remained isolated and resolved rapidly after shunt revision. In 21 cases the ocular signs were variably associated with other clinical manifestations such as pyramidal and extrapyramidal deficits, memory disturbances, mutism, or alterations in consciousness. Resolution of these symptoms after shunt revision was usually slow. In four cases a transient paradoxical aggravation was observed at the time of shunt revision. In 11 cases ventriculocistemostomy allowed resolution of the symptoms and withdrawal of the shunt. Simultaneous supratentorial and infratentorial intracranial pressure recordings performed in seven of the patients showed a pressure gradient between the supratentorial and infratentorial compartments, with a higher supratentorial pressure before shunt revision. Inversion of this pressure gradient was observed after shunt revision and resolution of the gradient was observed in one case after third ventriculostomy. In six recent cases, a focal midbrain hyperintensity was evidenced on T2-weighted magnetic resonance imaging sequences at the time of shunt malfunction. This rapidly resolved after the patient underwent third ventriculostomy. CONCLUSIONS: It is probable that in obstructive hydrocephalus, at the time of shunt malfunction, the development of a transtentorial pressure gradient could initially induce a functional impairment of the upper midbrain, inducing upward gaze palsy. The persistence of the gradient could lead to a global dysfunction of the upper midbrain. Third ventriculostomy contributes to equalization of cerebrospinal fluid pressure across the tentorium by restoring free communication between the infratentorial and supratentorial compartments, resulting in resolution of the patient's clinical symptoms.     

Efficacy of carbohydrate sources for milk production by cows fed diets based on alfalfa silage

The effectiveness of three carbohydrate sources, high-moisture ear corn (HMEC), cracked shelled corn (CSC), and a 50:50 mixture of HMEC plus dried citrus pulp (DCP), fed with or without supplemental rumen-undegraded protein as expeller soybean meal (ESBM), was assessed in 48 multiparous dairy cows. All diets contained (dry mater [DM] basis) 50% alfalfa silage, 10% ryegrass silage, 28% NDF, and one of six concentrates: A) 38% HMEC; B) 38% CSC; C) 19% DCP plus 19% HMEC; D) 27% HMEC plus 12% ESBM; E) 27% CSC plus 12% ESBM; or F) 13% DCP, 13% HMEC, and 12% ESBM. Diets A, B, and C averaged 19% crude protein, of which 53% was nonprotein nitrogen (NPN), and diets D, E, and F averaged 22% crude protein, of which 40% was NPN. Cows were fed a high-energy covariate diet for 2 wk, blocked into eight groups of six, based on covariate protein yield, then randomly assigned to diets that were fed for 12 wk. Feeding ESBM increased DM intake, yields of milk, fat-corrected milk, fat, protein, SNF, and milk and blood urea concentration and decreased weight loss. There were no production differences between HMEC and CSC. However, DM intake, yields of milk, fat-corrected milk, fat, protein, lactose, SNF, and milk SNF content all were lower on the diets containing DCP versus HMEC and CSC. A 6 x 6 Latin square trial conducted at the same time with six ruminally cannulated cows showed similar effects of diet on DM intake and milk production. Ruminal ammonia was elevated by ESBM but not ruminal total amino acids and branched-chain volatile fatty acids. Ruminal propionate was highest on HMEC diets and lowest on DCP diets; acetate, butyrate and acetate-to-propionate ratio were lowest on HMEC diets and highest on DCP diets. These results indicated that, compared to HMEC and CSC, feeding the pectin-rich carbohydrate source DCP altered ruminal fermentation but depressed intake and milk production in lactating cows.     

红曲与红曲色素的研究进展

阐述了红曲与红曲色素的各类，生产工艺及应用，介绍了红曲与红曲色素的现状和市场开发前景。     

基于光纤微弯的缠绕式管道形变传感器

利用多模光纤的微弯特性 ,提出并实现了一种新颖的光纤缠绕式管道形变传感器 ;也给出了它的基本实验原理 .研究表明多模光纤的微弯损耗对导管的变形响应灵敏 ,其灵敏度可达 3.5 d B/ με.并且实验与理论符合的很好     

Spontaneous orientation of transplanted olfactory glia influences axonal regeneration

Transplanted olfactory ensheathing cells (OECs) have previously been demonstrated to support axonal growth and myelination in the adult rat CNS. Here, the capacity of donor OECs to control the direction of axonal regeneration has been investigated following transplantation, as elongated columns, into the thalamus of adult rats. The OECs formed a 'glial bridge' which extended from the thalamus to the hippocampus. Transplanted OECs rapidly adopted a spindle-shaped morphology which was orientated along the vertical axis of the transplant. Numerous host axons grew into the transplants and followed the highly orientated OEC cell matrix across the choroid fissure. Thus, the spontaneous elongation and orientation of donor OECs may support highly directional host axonal growth across natural barriers within the CNS.     

Meta-analysis of multiple outcomes by regression with random effects

Earlier work showed how to perform fixed-effects meta-analysis of studies or trials when each provides results on more than one outcome per patient and these multiple outcomes are correlated. That fixed-effects generalized-least-squares approach analyzes the multiple outcomes jointly within a single model, and it can include covariates, such as duration of therapy or quality of trial, that may explain observed heterogeneity of results among the trials. Sometimes the covariates explain all the heterogeneity, and the fixed-effects regression model is appropriate. However, unexplained heterogeneity may often remain, even after taking into account known or suspected covariates. Because fixed-effects models do not make allowance for this remaining unexplained heterogeneity, the potential exists for bias in estimated coefficients, standard errors and p-values. We propose two random-effects approaches for the regression meta-analysis of multiple correlated outcomes. We compare their use with fixed-effects models and with separate-outcomes models in a meta-analysis of periodontal clinical trials. A simulation study shows the advantages of the random-effects approach. These methods also facilitate meta-analysis of trials that compare more than two treatments.     

GLUT4 and transferrin receptor are differentially sorted along the endocytic pathway in CHO cells

The trafficking of GLUT4, a facilitative glucose transporter, is examined in transfected CHO cells. In previous work, we expressed GLUT4 in neuroendocrine cells and fibroblasts and found that it was targeted to a population of small vesicles slightly larger than synaptic vesicles (Herman, G.A, F. Bonzelius, A.M. Cieutat, and R.B. Kelly. 1994. Proc. Natl. Acad. Sci. USA. 91: 12750-12754.). In this study, we demonstrate that at 37 degrees C, GLUT4-containing small vesicles (GSVs) are detected after cell surface radiolabeling of GLUT4 whereas uptake of radioiodinated human transferrin does not show appreciable accumulation within these small vesicles. Immunofluorescence microscopy experiments show that at 37 degrees C, cell surface-labeled GLUT4 as well as transferrin is internalized into peripheral and perinuclear structures. At 15 degrees C, endocytosis of GLUT4 continues to occur at a slowed rate, but whereas fluorescently labeled GLUT4 is seen to accumulate within large peripheral endosomes, no perinuclear structures are labeled, and no radiolabeled GSVs are detectable. Shifting cells to 37 degrees C after accumulating labeled GLUT4 at 15 degrees C results in the reappearance of GLUT4 in perinuclear structures and GSV reformation. Cytosol acidification or treatment with hypertonic media containing sucrose prevents the exit of GLUT4 from peripheral endosomes as well as GSV formation, suggesting that coat proteins may be involved in the endocytic trafficking of GLUT4. In contrast, at 15 degrees C, transferrin continues to traffic to perinuclear structures and overall labels structures similar in distribution to those observed at 37 degrees C. Furthermore, treatment with hypertonic media has no apparent effect on transferrin trafficking from peripheral endosomes. Double-labeling experiments after the internalization of both transferrin and surface-labeled GLUT4 show that GLUT4 accumulates within peripheral compartments that exclude the transferrin receptor (TfR) at both 15 degrees and 37 degrees C. Thus, GLUT4 is sorted differently from the transferrin receptor as evidenced by the targeting of each protein to distinct early endosomal compartments and by the formation of GSVs. These results suggest that the sorting of GLUT4 from TfR may occur primarily at the level of the plasma membrane into distinct endosomes and that the organization of the endocytic system in CHO cells more closely resembles that of neuroendocrine cells than previously appreciated.