受控的大电流—紧凑型汽车动力系统

本文介绍了带有低压MOSFET或高压IGBT功率器件的SKAI汽车动力系统的性能和应用。     

Involvement of carboxy-terminal amino acids in secretion of human lysosomal protease cathepsin L

Cathepsin L, a lysosomal cysteine protease, is overexpressed and secreted by malignantly transformed cells. However, the reason for secretion of this man 6-phosphate-containing lysosomal protease into the extracellular medium is not clear. We wished to determine whether there is a region within the primary sequence of the proenzyme form of cathepsin L which affects its subcellular and extracellular localization. High-level transient expression of human procathepsin L in mouse NIH 3T3 cells results in the secretion of most of this protein into the extracellular medium. At the same time, the endogenous mouse procathepsin L in these nontransformed cells is found in its usual location in lysosomes. Mutants of human procathepsin L with carboxy-terminus deletions involving the last 11 amino acids are not secreted into the medium. Deletion of as little as two amino acids, Thr and Val, from the carboxy terminus, blocked the secretion of the protein but did not affect its enzyme activity, posttranslational processing, or subcellular distribution. Replacement of Thr-Val by two bulky amino acids Tyr-Asn allowed secretion of the procathepsin L, but the replacement of these two amino acids by nonbulky alanines prevented its secretion. Single alanine substitutions of the last six amino acids (ASYPTV) indicated that substitution by alanine of Y or T does not affect the secretion of hproCAT L, but alanine substitutions of S, P, or V completely blocked its secretion into the culture medium. We therefore conclude that the carboxy terminus of procathepsin L contains a sequence essential for its secretion.     

The thrill of victory and the agony of defeat: Spontaneous expressions of medal winners of the 2004 Athens Olympic games.

Facial behaviors of medal winners of the judo competition at the 2004 Athens Olympic Games were coded with P. Ekman and W. V. Friesen's (1978) Facial Affect Coding System (FACS) and interpreted using their Emotion FACS dictionary. Winners' spontaneous expressions were captured immediately when they completed medal matches, when they received their medal from a dignitary, and when they posed on the podium. The 84 athletes who contributed expressions came from 35 countries. The findings strongly supported the notion that expressions occur in relation to emotionally evocative contexts in people of all cultures, that these expressions correspond to the facial expressions of emotion considered to be universal, that expressions provide information that can reliably differentiate the antecedent situations that produced them, and that expressions that occur without inhibition are different than those that occur in social and interactive settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A neuropsychological theory of motor skill learning

This article describes a neuropsychological theory of motor skill learning that is based on the idea that learning grows directly out of motor control processes. Three motor control processes may be tuned to specific tasks, thereby improving performance: selecting spatial targets for movement, sequencing these targets, and transforming them into muscle commands. These processes operate outside of awareness. A 4th, conscious process can improve performance in either of 2 ways: by selecting more effective goals of what should be changed in the environment or by selecting and sequencing spatial targets. The theory accounts for patterns of impairment of motor skill learning in patient populations and for learning-related changes in activity in functional imaging studies. It also makes a number of predictions about the purely cognitive, including accounts of mental practice, the representation of motor skill, and the interaction of conscious and unconscious processes in motor skill learning.     

The Visual Reproduction subtest: Standardization and clinical validation of a delayed recall procedure.

Provided a normative database for a delayed recall procedure using the Visual Reproduction subtest from Form I of the Wechsler Memory Scale and examined the test's clinical sensitivity in 4 groups of patients. Normative data were based on 255 neurologically normal adults (aged 18–91 yrs). Clinical groups included 103 patients with severe head trauma, left hemisphere cerebrovascular accident (CVA), right hemisphere CVA, and Alzheimer's disease (mean ages 28.85, 63.46, 64.21, and 64.85 yrs, respectively). Normative data revealed significant age-related differences, with older Ss performing lower on both immediate and delayed recall tasks. Ss in all 4 clinical groups performed significantly below age-matched controls. Visual Reproduction scores correlated positively with measures of visual-spatial ability, verbal memory, and visual memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of the effects of porous media structure on mixing-controlled reactions using pore-scale modeling and micromodel experiments

The objectives of this work were to determine if a pore-scale model could accurately capture the physical and chemical processes that control transverse mixing and reaction in microfluidic pore structures (i.e., micromodels), and to directly evaluate the effects of porous media geometry on a transverse mixing-limited chemical reaction. We directly compare pore-scale numerical simulations using a lattice-Boltzmann finite volume model (LB-FVM) with micromodel experiments using identical pore structures and flow rates, and we examine the effects of grain size, grain orientation, and intraparticle porosity upon the extent of a fast bimolecular reaction. For both the micromodel experiments and LB-FVM simulations, two reactive substrates are introduced into a network of pores via two separate and parallel fluid streams. The substrates mix within the porous media transverse to flow and undergo instantaneous reaction. Results indicate that (i) the LB-FVM simulations accurately captured the physical and chemical process in the micromodel experiments, (ii) grain size alone is not sufficient to quantify mixing at the pore scale, (iii) interfacial contact area between reactive species plumes is a controlling factor for mixing and extent of chemical reaction, (iv) at steady state, mixing and chemical reaction can occur within aggregates due to interconnected intra-aggregate porosity, (v) grain orientation significantly affects mixing and extent of reaction, and (vi) flow focusing enhances transverse mixing by bringing stream lines which were initially distal into close proximity thereby enhancing transverse concentration gradients. This study suggests that subcontinuum effects can play an important role in the overall extent of mixing and reaction in groundwater, and hence may need to be considered when evaluating reactive transport.     

Motor skills have diverse neural bases: Spared and impaired skill acquisition in Huntington's disease.

The striatum contributes to the learning of some, but not all, motor skills. The researchers suggest that the striatum plays a role when participants learn a repeating sequence of movements, but it does not contribute when they learn a new mapping between perceptual cues and the appropriate motor response. The researchers tested patients with striatal damage due to Huntington's disease (HD) on 2 versions of a tracking task. In 1 task, the target moved randomly, allowing participants to learn the relationship between the joystick and cursor. Patients showed normal learning. In the other task, the target moved in a repeating pattern, and participants could improve performance by learning the repeating sequence of movements necessary to track the pattern. Patients were impaired on this task. Learning sequences is impaired in HD, whereas learning new mappings between perceptual cues and responses is not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interdependence of successive absolute judgments.

The aim was "to determine whether successive absolute judgments of a cognitive nature are interdependent, and if so, to evaluate a method for controlling this bias." The design involved rating populations of countries, with one group of Ss rating a "test" country following rating of a sparsely populated one and a second group following the rating of a populous country. This type of design was used several times in longer lists of words. Results of 8 test items indicated that "ratings tend to be biased in the direction of the previous rating… bias increases as the number of response categories increases." When the Ss were instructed to rate extreme stimuli first, no bias effect was found. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the development of procedural knowledge.

Amnesic patients demonstrate by their performance on a serial reaction time task that they learned a repeating spatial sequence despite their lack of awareness of the repetition (M. J. Nissen and P. Bullemer; see PA Vol 74:13436). In the experiments reported here, we investigated this form of procedural learning in normal subjects. A subgroup of subjects showed substantial procedural learning of the sequence in the absence of explicit declarative knowledge of it. Their ability to generate the sequence was effectively at chance and showed no savings in learning. Additional amounts of training increased both procedural and declarative knowledge of the sequence. Development of knowledge in one system seems not to depend on knowledge in the other. Procedural learning in this situation is neither solely perceptual nor solely motor. The learning shows minimal transfer to a situation employing the same motor sequence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of ectopic overexpression of p21(WAF1/CIP1) on aneuploidy and the malignant phenotype of human brain tumor cells

p21WAF1/CIP1 is a downstream effector of the p53 tumor suppressor gene and a universal cyclin-dependent kinase (CDK) inhibitor. To determine the ability of p21WAF1/CIP1 to function as a tumor suppressor, we constructed a replication-defective adenovirus vector containing p21WAF1/CIP1 (Adp21WAF1/CIP1) to effect ectopic overexpression in a p53-defective human astrocytoma cell line, U-373MG. We observed a marked decrease in CDC2 and CDK2 kinase activity associated with a corresponding decrease in the amount of CDC2 but not CDK2 protein; a decreased growth potential of Adp21WAF1/CIP1-infected cells demonstrated by diminished [3H]thymidine incorporation, increased cell doubling time and G1-arrested cell cycle; an association between Adp21WAF1/CIP1-infected cells and inhibition of aneuploid cell accumulation; and an alteration of the malignant phenotype of cells was evidenced by the loss of anchorage-independent growth in soft agar and the failure to induce tumorigenesis in both peripheral and intracerebral xenograft models, including the prevention of tumor formation Adp21WAF1/CIP1 infection 2 days post tumor cell implantation. Adp21WAF1/CIP1. Adp21WAF1/CIP1 appears to be a strong candidate for gene therapy studies based on these studies indicating that Adp21WAF1/CIP1 inhibits proliferation, tumorigenicity and aneuploidy in human brain tumor cells.