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41.
Age-dependent MRI-detected lesions at early stages of transient global ischemia in rat brain 总被引:2,自引:0,他引:2
Canese R Lorenzini P Fortuna S Volpe MT Giannini M Podo F Michalek H 《Magma (New York, N.Y.)》2004,17(3-6):109-116
Although ischemic stroke has higher incidence and severity in aged than in young humans, the age factor is generally neglected in ischemia animal models. This study was aimed at comparing age-dependent effects at early stages of transient global cerebral ischemia (TGCI) in rats. TGCI was induced in two groups of rats (3–6 and 20–24 months old, respectively) by exposure to 15% oxygen and 15 min occlusion of the two common carotid arteries. Brains were analysed in vivo by MRI–apparent diffusion coefficient (ADC) and T2 maps–at 1–3 h post-TGCI and in vitro by histochemical examination of triphenyltetrazolium chloride (TTC)-stained slices. At 1–3 h post-TGCI, a higher incidence of lesions was found in aged than in young rats especially in the hippocampus and cortex (occipital plus parietal) but not in the thalamus. The lesioned regions showed lower ADC values in aged than in younger rats. The most substantial ADC decreases were associated with enhanced spin-spin relaxation and lower TTC staining. The different responses of the two age groups support the use of aged animals for investigations on different ischemia models. Our model of brain ischemia appears appropriate for further studies including drug effects. 相似文献
42.
Jeong Yeob Han Ph.D. Meg Wise Ph.D. Eunkyung Kim Ph.D. Candidate Ray Pingree Ph.D. Robert P. Hawkins Ph.D. Suzanne Pingree Ph.D. Fiona McTavish M.S. David H. Gustafson Ph.D. 《Journal of Computer-Mediated Communication》2010,15(3):367-388
In order to provide insights about cancer patients' online information seeking behaviors, the present study analyzes individuals' transaction log data and reports on how demographics, disease‐related factors, and psychosocial needs predict patterns of service use within a particular Interactive Cancer Communication System (ICCS). Study sample included 294 recently diagnosed breast cancer patients. Data included pretest survey scores of demographic, disease‐related, and psychosocial factors and automatically collected ICCS use data over the 4‐month intervention. Statistical analyses correlated pre‐test survey scores with subsequent, specific types of ICCS service usage. Patterns of online cancer information seeking differed according to the patients' characteristics, suggesting that lower income, less educated women and those lacking in information‐seeking competence use the computer and online services to the same or a greater degree if those services are made available to them. Results of this study can inform more effective resource development for future eHealth applications. 相似文献
43.
A crude lipophilic extract and specific pure metabolites of the soft coral Sinularia flexibilis have been examined for algacidal properties both in laboratory and field experiments. Laboratory algal bioassays, in which cultures of the common fouling alga Ceramium codii were incubated with six different diterpenes isolated from S. flexibilisrevealed that 11-episinulariolide exhibits strong algacidal properties. Field experiments carried out with treated settlement tiles confirmed the laboratory findings and provided evidence for the algacidal properties of 11-episinulariolide against several other common reef algae. Sinulariolide, which had previously been reported to inhibit the growth of unicellular algae, was approximately one third as effective as its stereoisomer 11-episinulariolide in the laboratory growth inhibition bioassay and showed no significant algacidal properties at the concentrations used in the field experiments. 相似文献
44.
Dr. N. Amy Yewdall Bastiaan C. Buddingh Wiggert J. Altenburg Suzanne B. P. E. Timmermans Daan F. M. Vervoort Prof. Loai K. E. A. Abdelmohsen Dr. Alexander F. Mason Prof. Jan C. M. van Hest 《Chembiochem : a European journal of chemical biology》2019,20(20):2643-2652
The bottom-up construction of cell mimics has produced a range of membrane-bound protocells that have been endowed with functionality and biochemical processes reminiscent of living systems. The contents of these compartments, however, experience semidilute conditions, whereas macromolecules in the cytosol exist in protein-rich, crowded environments that affect their physicochemical properties, such as diffusion and catalytic activity. Recently, complex coacervates have emerged as attractive protocellular models because their condensed interiors would be expected to mimic this crowding better. Here we explore some relevant physicochemical properties of a recently developed polymer-stabilized coacervate system, such as the diffusion of macromolecules in the condensed coacervate phase, relative to in dilute solutions, the buffering capacity of the core, the molecular organization of the polymer membrane, the permeability characteristics of this membrane towards a wide range of compounds, and the behavior of a simple enzymatic reaction. In addition, either the coacervate charge or the cargo charge is engineered to allow the selective loading of protein cargo into the coacervate protocells. Our in-depth characterization has revealed that these polymer-stabilized coacervate protocells have many desirable properties, thus making them attractive candidates for the investigation of biochemical processes in stable, controlled, tunable, and increasingly cell-like environments. 相似文献
45.
There is strong evidence for the protective effects of physical activity on chronic health problems. Activity monitors can objectively measure free living occupational and leisure time physical activity. Utility is an important consideration when determining the most appropriate monitor for specific populations and environments. Hours of activity data collected, the reasons for activity hours not being recorded, and how these two factors might change over time when using an activity monitor in free living are rarely reported. This study investigated user perceptions, adherence to minimal wear time and loss of data when using the RT3 activity monitor in 21 healthy adults, in a variety of occupations, over three (7 day) repeated weeks of measurement in free living. An activity diary verified each day of monitoring and a utility questionnaire explored participant perceptions on the usability of the RT3. The RT3 was worn for an average of 14 h daily with 90% of participants having complete data sets. In total 6535.8 and 6092.5 h of activity data were collected from the activity diary and the RT3 respectively. An estimated 443.3 h (6.7%) of activity data were not recorded by the RT3. Data loss was primarily due to battery malfunction (45.2%). Non-adherence to wear time accounted for 169.5 h (38.2%) of data loss, of which 14 h were due to occupational factors. The RT3 demonstrates good utility for free living activity measurement, however, technical issues and strategies to manage participant adherence require consideration with longitudinal and repeated measures studies. 相似文献
46.
Outsourced information systems development (OISD) projects are challenging endeavors, and the literature suggests differences between the parties involved as critical hinderers of such projects. Using institutional theory as a foundational theory, we propose a process explanation of the effects of differences between parties in OISD projects. Our explanation relies on the interaction of four components: (1) the IS development and project management institutional profiles of the parties involved; (2) the institutional distance between practices within these profiles; (3) instances of conflicting institutional demands when institutional distance becomes salient; and (4) the repertoire of institutional strategic responses available to parties to address those instances. We suggest that the constitutive elements of institutional distance and the degree to which parties envision their collaboration beyond the project at hand contribute to explaining the enactment of strategic responses. Accounting for the fact that practices, as well as the institutional logics that drive their enactment, may differ between parties, we make a theoretical contribution to the literature on OISD by building a fine-grained explanation of the effects of differences between parties in OISD projects. 相似文献
47.
Jane Ndungu Bruce C. Monger Denie C.M. Augustijn Suzanne J.M.H. Hulscher Nzula Kitaka Jude M. Mathooko 《International journal of remote sensing》2013,34(22):8142-8155
Restoration of the ecosystem services and functions of lakes requires an understanding of the turbidity dynamics in order to arrive at informed environmental management decisions. The understanding of the spatio-temporal dynamics of turbidity requires frequent monitoring of the turbidity components such as chlorophyll-a concentration. In this study, we explored the use of Moderate Resolution Imaging Spectroradiometer Aqua (MODIS-Aqua) satellite data in studying the spatio-temporal changes in chlorophyll-a concentration in Lake Naivasha, a turbid tropical system. The temporal trend of chlorophyll-a concentration over the study period in the lake was also evaluated. The temporal trend assessment was achieved through the removal of periodic seasonal interference using Seasonal-Trend decomposition based on the LOESS (Local Regression) procedure. The resultant chlorophyll-a concentration maps derived from MODIS-Aqua satellite data give an indication of the monthly spatial variation in chlorophyll-a concentration from 2002 to 2012. The results of regression analyses between satellite-derived chlorophyll-a and in situ measurements reveal a high level of precision, but with a measureable bias with the satellite underestimating actual in situ measurements (R2 = 0.65, P < 0.001). Although the actual values of the chlorophyll-a concentrations are underestimated, the significant relationship between satellite-derived chlorophyll-a and in situ measurements provides reliable information for studying spatial variations and temporal trends. In 2009 and 2010, it was difficult to detect chlorophyll-a from the MODIS-Aqua imagery, and this coincided with a period of the lowest water levels in Lake Naivasha. An inverse relationship between de-seasoned water level and chlorophyll-a concentration was evident. This study shows that MODIS-Aqua satellite data provide useful information on the spatio-temporal variations in Lake Naivasha, which is useful in establishing general trends that are more difficult to determine through routine ground measurements. 相似文献
48.
The use of rules in a distributed environment creates new challenges for the development of active rule execution models. In particular, since a single event can trigger multiple rules that execute over distributed sources of data, it is important to make use of concurrent rule execution whenever possible. This paper presents the details of the integration rule scheduling (IRS) algorithm. Integration rules are active database rules that are used for component integration in a distributed environment. The IRS algorithm identifies rule conflicts for multiple rules triggered by the same event through static, compile-time analysis of the read and write sets of each rule. A unique aspect of the algorithm is that the conflict analysis includes the effects of nested rule execution that occurs as a result of using an execution model with an immediate coupling mode. The algorithm therefore identifies conflicts that may occur as a result of the concurrent execution of different rule triggering sequences. The rules are then formed into a priority graph before execution, defining the order in which rules triggered by the same event should be processed. Rules with the same priority can be executed concurrently. The IRS algorithm guarantees confluence in the final state of the rule execution. The IRS algorithm is applicable for rule scheduling in both distributed and centralized rule execution environments. 相似文献
49.
Attachment, separation, and women's vocational development: A longitudinal analysis. 总被引:1,自引:0,他引:1
O'Brien Karen M.; Friedman Suzanne Miller; Tipton Linda C.; Linn Sonja Geschmay 《Canadian Metallurgical Quarterly》2000,47(3):301
This study tested a proposed model investigating the relations among attachment to and separation from parents, career self-efficacy, and career aspiration over a 5-year period with a sample of 207 young women. Results suggested that being attached to parents may lead to the development of confidence in pursuing career-related tasks, which in turn influences career aspiration. Separation from parents did not have direct effects on career self-efficacy. Results also indicated that women's career plans changed over a 5-year period with young women selecting more traditional and less prestigious careers than those to which they aspired in their senior year of high school. In addition, these women chose careers that underutilized their abilities. Finally, this sample of young women intended to have both careers and families, and the majority of these women ranked family as more important than career. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
50.
Suzanne Strum 《Nexus Network Journal》2012,14(1):35-52
This paper offers an account of the unusual protosystemic and informational approach to architecture that emerged in the early 1930’s within the largely unknown Structural Study Associates (SSA), a circle of architects around Buckminster Fuller. It examines the design of a dynamic information system for architects by SSA members Knud L?nberg-Holm and Carl Theodore Larson and compares them to pre- and post-war knowledge indexing systems and world projects. This study also explores the systems-oriented positions outlined by these architects. This provides a view of American architecture of the era that counters the one presented by the canonical International Style Exhibition of 1932, which essentially edited out the more variegated approaches to modern architecture and technology as represented by the SSA and especially L?nberg-Holm. 相似文献