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排序方式: 共有5073条查询结果,搜索用时 15 毫秒
951.
C Ponticelli P Altieri F Scolari P Passerini D Roccatello B Cesana P Melis B Valzorio M Sasdelli S Pasquali C Pozzi G Piccoli A Lupo S Segagni F Antonucci M Dugo M Minari A Scalia L Pedrini G Pisano C Grassi M Farina R Bellazzi 《Canadian Metallurgical Quarterly》1998,9(3):444-450
Recent research on development of the implantable artificial pancreas for treatment of diabetes is reviewed, based on a Medline literature search that focused on glucose sensors, insulin pumps, and pump control systems. To achieve a closed feedback loop, a clinically applicable implantable artificial pancreas requires miniaturization and coordination of three components: an insulin pump, a blood glucose monitor, and a control system. Recent clinical studies have demonstrated that implantable insulin pumps are feasible for satisfactory control of diabetes for over a year, with the major complication being obstruction of the infusion catheter. Research on continuous glucose sensors has predominantly used the glucose-oxidase reaction or near-infrared light spectroscopy. Implantable glucose oxidase sensors have been limited by local factors causing unstable signal output, whereas optical sensors must overcome interference by substances with absorption spectra similar to glucose. Investigators have developed control algorithms in an effort to stabilize operation of the integrated artificial pancreas in the face of variations in sensor output and pump function. The ultimate goals of fully automatic glucose control by an artificial pancreas include prevention or delay of chronic complications of diabetes, lowered risk of hypoglycemia, and less patient inconvenience and discomfort than with multiple daily glucose self-tests and insulin injection. The recent developments of optical glucose sensing, radiotelemetry systems to link pump and sensor, and miniaturization and refinement of insulin pumps are significant steps toward a clinically applicable artificial pancreas. 相似文献
952.
DL Kirkpatrick M Kuperus M Dowdeswell N Potier LJ Donald M Kunkel M Berggren M Angulo G Powis 《Canadian Metallurgical Quarterly》1998,55(7):987-994
The interactions of a series of 2-imidazolyl disulfide antitumor compounds with the thioredoxin reductase(TR)/thioredoxin (hTrx) redox system have been studied. Disulfides III-2 (n-butyl 2-mercaptoimidazolyl disulfide) and VI-2 (ethyl 2-mercaptoimidazolyl disulfide) were substrates for reduction by TR with Km values of 43 and 48 microM. Disulfides IV-2 (1-methylpropyl 2-mercaptoimidazolyl disulfide) and DLK-36 (benzyl 2-mercaptoimidazolyl disulfide) were competitive inhibitors of the reduction of hTrx by TR with Ki values of 31 microM. None of the disulfides were substrates for reduction by human glutathione reductase. The disulfides caused reversible thioalkylation of hTrx at the redox catalytic site as shown by the fact that there was no thioalkylation of a mutant hTrx where both the catalytic site Cys32 and Cys35 residues were replaced by Ser. In addition, the disulfides caused a slower irreversible inactivation of hTrx as a substrate for reduction by TR, with half-lives for III-2 of 30 min, for IV-2 of 4 hr, and for IX-2 (t-butyl 2-mercaptoimidazolyl disulfide) of 24 hr. This irreversible inactivation of hTrx occurred at concentrations of the disulfides an order of magnitude below those that inhibited TR, and involved the Cys73 of hTrx, which is outside the conserved redox catalytic site, as shown by the resistance to inactivation of a mutant hTrx where Cys73 was replaced by Ser. Electrophoretic and mass spectral analyses of the products of the reaction between the disulfides and hTrx show that modification of 1-3 Cys residues of the protein occurred in a concentration-dependent fashion. The disulfides inhibited the hTrx-dependent proliferation of MCF-7 breast cancer cells with IC50 values for III-2 and IV-2 of 0.2 and 1.2 microM, respectively. The results show that although the catalytic sites of TR and hTrx are reversibly inhibited by the 2-imidazolyl disulfides, it is the irreversible thioalkylation of Cys73 of hTrx by the disulfides that most probably accounts for the inhibition of thioredoxin-dependent cell growth by the disulfides. 相似文献
953.
954.
Blanchard Kimberly A.; Morgenstern Jon; Morgan Thomas J.; Lobouvie Erich W.; Bux Donald A. 《Canadian Metallurgical Quarterly》2003,17(4):328
Negative consequences are an important component of the substance use change process, yet no standardized measure exists to assess consequences of use. This study evaluated the psychometric properties of the Inventory of Drug Use Consequences, a self-report measure assessing drinking and drug use consequences. Participants (N=252) were assessed at entry into outpatient substance abuse treatment. Items loaded strongly on 1 factor, and internal consistency of the total scale was high. Fifteen items with the highest correlations with the total scale were chosen to represent the construct. The shortened measure exhibited good internal consistency, convergent and discriminant validity, and detected change over time and may be the measure of substance use consequences that is lacking in the field. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
955.
The present study explores the relation among 4 personality traits associated with impulsive behavior and alcohol abuse. Personality traits were measured using the 4 subscales of the UPPS Impulsive Behavior Scale (UPPS: S. P. Whiteside & D. R. Lynam. 2001). The UPPS and measures of psychopathology were administered to clinical samples of alcohol abusers high in antisocial personality traits (AAPD), alcohol abusers low in antisocial personality traits (AA), and a control group (total N = 60). Separate analyses of variance indicated that AAPDs had significant elevations on all 4 UPPS scales, whereas the AAs and controls differed only on the Urgency subscale. However, when controlling for psychopathology, group differences on the UPPS scales disappeared. The results suggest that personality traits related to impulsive behavior are not directly related to alcohol abuse but rather are associated with the elevated levels of psychopathology found in a subtype of alcohol abusers. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
956.
Dimitrios Georgakopoulos Donald Baker Marian Nodine Andrzej Cichoki 《World Wide Web》2007,10(1):85-109
The Video Event Awareness Workbench (VEAW) analyzes surveillance video from thousands of video cameras and automatically detects complex events in near-real-time-at pace with their input video streams. For events of interest to security personnel, VEAW generates and routes alerts and related video evidence to subscribing security personnel. Complex event processing in VEAW is driven by user-authored awareness specifications comprised of inter-connected spatio-temporal stream and statistical operators that consume and produce events described in VEAW’s surveillance ontology. In this paper we introduce VEAW’s event driven architecture and describe its solutions for automating video surveillance, including the orchestration of continuous and tasked video analysis algorithms (e.g., for entity tracking and identification), fusion of events from multiple sources in an installation-specific “world” model, and proactive information gathering to deal with missing or incomplete information (this is done by tasking video analysis algorithms and security personnel to provide it). We also discuss how VEAW deals with late arriving information (due to out-of-band video analysis tasks and overhead), as well as a related resource optimization aimed at minimizing computation costs. We illustrate the benefits of VEAW by illustrating its application on the automation of real-world security policies. 相似文献
957.
Lynam Donald R.; Gaughan Eric T.; Miller Joshua D.; Miller Drew J.; Mullins-Sweatt Stephanie; Widiger Thomas A. 《Canadian Metallurgical Quarterly》2011,23(1):108
A new self-report assessment of the basic traits of psychopathy was developed with a general trait model of personality (five-factor model [FFM]) as a framework. Scales were written to assess maladaptive variants of the 18 FFM traits that are robustly related to psychopathy across a variety of perspectives including empirical correlations, expert ratings, and translations of extant assessments. Across 3 independent undergraduate samples (N = 210–354), the Elemental Psychopathy Assessment (EPA) scales proved to be internally consistent and unidimensional, and were strongly related to the original FFM scales from which they were derived (mean convergent r = .66). The EPA scales also demonstrated substantial incremental validity in the prediction of existing psychopathy measures over their FFM counterparts. When summed to form a psychopathy total score, the EPA was substantially correlated with 3 commonly used psychopathy measures (mean r = .81). Finally, in a small male forensic sample (N = 70), the EPA was significantly correlated with scores on a widely used self-report psychopathy measure, disciplinary infractions, alcohol use, and antisocial behavior. The EPA provides an opportunity to examine psychopathy and its nomological network through smaller, more basic units of personality rather than by scales or factors that blend these elements. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
958.
Lynam Donald R.; Miller Joshua D.; Miller Drew J.; Bornovalova Marina A.; Lejuez C. W. 《Canadian Metallurgical Quarterly》2011,2(2):151
Borderline personality disorder (BPD) has received significant attention as a predictor of suicidal behavior (SB) and nonsuicidal self-injury (NSSI). Despite significant promise, trait impulsivity has received less attention. Understanding the relations between impulsivity and SB and NSSI is confounded, unfortunately, by the heterogeneous nature of impulsivity. This study examined the relations among 4 personality pathways to impulsive behavior studied via the UPPS model of impulsivity and SB and NSSI in a residential sample of drug abusers (N = 76). In this study, we tested whether these 4 impulsivity-related traits (i.e., Negative Urgency, Sensation Seeking, Lack of Premeditation, and Lack of Perseverance) provide incremental validity in the statistical prediction of SB and NSSI above and beyond BPD; they do. We also tested whether BPD symptoms provide incremental validity in the prediction of SB and NSSI above and beyond these impulsivity-related traits; they do not. In addition to the main effects of Lack of Premeditation and Negative Urgency, we found evidence of a robust interaction between these 2 personality traits. The current results argue strongly for the consideration of these 2 impulsivity-related domains—alone and in interaction—when attempting to understand and predict SB and NSSI. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
959.
Frederick Donald E.; Rojas-Líbano Daniel; Scott Meagen; Kay Leslie M. 《Canadian Metallurgical Quarterly》2011,125(4):588
To elucidate the cognitive structures of animals, neuroscientists use several behavioral tasks. Therefore, it is imperative to have a firm understanding of each task's behavioral parameters in order to parse out possible task effects. We compare two operant discrimination tasks (Go/No-Go: GNG; Two-Alternative Choice: TAC) that are commonly used in olfactory research. Past research has suggested that solving the two tasks requires divergent cognitive strategies. One hypothesis is that the two tasks differ in how an animal optimizes reward rate by means of a speed–accuracy trade-off (SAT). If this is true, then changing tasks could give researchers an additional tool to understand animal cognition. However, no study has systematically analyzed the two tasks in parallel using odor stimuli. Using standardized training protocols, we test GNG and TAC in parallel. Our protocols allow us to isolate the stimulus sampling period from a general reaction time period. We find that the two tasks do not differ with regard to the stimulus sampling period and conclude that the two tasks do not differ in the amount of time it takes an animal to perform a discrimination. Instead, tasks differ in the time it takes to make an overt behavioral response, with GNG showing shorter periods than TAC. We also find no evidence of rats using either task-specific or intertrial interval-dependent SAT schema in order to optimize reward rate. We show that similarities between dependent variables, with the possible exception of response delay, appear to be under experimenter control. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
960.
Pettifor Jean; McCarron Michelle C. E.; Schoepp Greg; Stark Cannie; Stewart Donald 《Canadian Metallurgical Quarterly》2011,52(3):198
Supervision is a specialized area of psychological activity that has its own foundation of knowledge, skills, and attitudes, which are enhanced by training. As our discipline develops its standards for competent practice in supervision, there is a need to develop ethical guidelines to assist both supervisors and supervisees in maintaining productive working relationships. Organized around the hierarchy of ethical principles comprising the Canadian Code of Ethics for Psychologists, the Canadian Psychological Association adopted Ethical Guidelines for Supervision in Psychology: Teaching, Research, Practice, and Administration in early 2009. In this article, each of the four ethical principles (Respect for the Dignity of Persons, Responsible Caring, Integrity in Relationships, and Responsibility to Society) is examined in the context of supervision within the areas of teaching, research, practice, and administration. The history of the guidelines, as well as some of their innovative and unique elements, is also discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献