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531.
Rahat Kumar Narinder Singh Kartar Singh Atul Kalhan K. K. Prasad 《Indian journal of clinical biochemistry : IJCB》2004,19(1):122-128
The normal coagulation process is initiated by disruption and exposure of the subendothelial components of blood vessels.
Platelets adhere to subendothelium-bound von Willebrand factor via glycoprotein (GP) Ib complex. This initial interaction
per se and the release of platelet agonists transduce signals that leads to the rise in intracellular Ca2+ which induces shape
change, prostaglandin synthesis, release of granular contents and conformational changes in platelet Gp IIb-IIIa. Gp IIb-IIIa
in activated platelets binds fibrinogen and other adhesive proteins and mediates platelet cohesion the primary haemostatic
plug. Furthermore, the activated platelets due to aggregation, result in the formation of fibrin (secondary hemostasis). Normally
the haemostatic process plays a delicate balance between keeping the blood in the fluid state to maintain flow and rapidly
forming an occluding plug following vessel injury. Thrombosis occurs because of alteration in this delicate balance. Arterial
thrombosis occurs in the setting of previous vessel wall injury mostly because of atherosclerosis, while venous thrombosis
occurs in areas of stasis. The recent advances in understanding of the haemostatic process have led to a better understanding
of the mechanism of action of many antithrombotic drugs and identification of new targets for drug development. The molecular
target of the ticlopidine has been identified. Large numbers of IIb-IIIa inhibitors have been developed. The mechanism of
action of heparin has been defined at the molecular level. As a result, a synthetic pentasaccharide, based on antithrombin-binding
domain of heparin, has been developed and tested successfully in clinical trials. New generation direct thrombin inhibitors
are being developed. Factor Xa has a critical position at the convergence of intrinsic and extrinsic pathway. The clinical
tolerability and the efficacy of low molecular weight heparins has established that inhibition of further thrombin generation,
by blocking factor Xa alone can be an effective way of preventing thrombus growth without inactivating thrombin. A large number
of specific factor Xa inhibitors are under development. Some of these are in preliminary clinical trials and appear to be
promising. Future clinical trials will determine whether these new drugs will provide better risk-benefit ratio in treatment
of thrombotic disorders. Similarly role of thrombolytics has been clearly established in many diseases including coronary
artery disease. 相似文献
532.
This paper examines stability and change during the elementary-to-middle school transition, focusing on adolescents’ experiences of home–school dissonance because of real or perceived differences between home/self and values within the school context. Relationships were hypothesized between exacerbation and amelioration of dissonance, middle school mastery and performance goal practices, and students’ perceptions thereof. The sample consisted of 274 African-American and 284 European-American (49% female) students. Middle school teachers (N = 236) provided data on school academic practices. Multilevel growth curve analysis indicated significant variance among the 10 middle schools regarding change in dissonance. Both mastery-focused middle school practices and students’ perception of middle school classrooms as more performance and less mastery focused than elementary classrooms were significant predictors of change in dissonance. Path-analyses evidence pointed to the mediational role of school belonging on the relationship between perception of classroom mastery goals and dissonance. Path analyses revealed direct and indirect effects of perception of classroom performance goals on dissonance and school belonging. This paper highlights the importance of creating inclusive learning environments that minimize social comparison saliency and validate students for who they are. 相似文献
533.
The semiconductor industry operates in a constant state of deflation. It is vital to our survival and progress in this knowledge era. The industry is extremely competitive and requires ongoing technological advances to improve performance while reducing costs to remain competitive. Gaining an understanding of important facets of this industry is essential. Besides knowing about semiconductor history, other aspects of interest include types of semiconductor products in the marketplace and their uses, typical semiconductor-chip making process, overall industry review and trends. One critical tool used by the industry to direct product and technology development is a technology roadmap. Review of the initial and current semiconductor technology roadmap would further enhance our understanding of semiconductor industry. 相似文献
534.
The chemical modifications that occur during vulcanization of rubber and methods for controlling the process are discussed. 相似文献
535.
Wei-Kai Liou Kaushal Kumar Bhagat Chun-Yen Chang 《Journal of Science Education and Technology》2016,25(3):460-473
The present study compares the highly interactive cloud-classroom (HIC) system with traditional methods of teaching materials science that utilize crystal structure picture or real crystal structure model, in order to examine its learning effectiveness across three dimensions: knowledge, comprehension and application. The aim of this study was to evaluate the (HIC) system, which incorporates augmented reality, virtual reality and cloud-classroom to teach basic materials science courses. The study followed a pretest–posttest quasi-experimental research design. A total of 92 students (aged 19–20 years), in a second-year undergraduate program, participated in this 18-week-long experiment. The students were divided into an experimental group and a control group. The experimental group (36 males and 10 females) was instructed utilizing the HIC system, while the control group (34 males and 12 females) was led through traditional teaching methods. Pretest, posttest, and delayed posttest scores were evaluated by multivariate analysis of covariance. The results indicated that participants in the experimental group who used the HIC system outperformed the control group, in the both posttest and delayed posttest, across three learning dimensions. Based on these results, the HIC system is recommended to be incorporated in formal materials science learning settings. 相似文献
536.
Hemanth Tumkur Lakshmikantha Naresh Kumar Ravichandran Mansik Jeon Jeehyun Kim Hyo-sang Park 《Journal of Zhejiang University. Science. B》2018,19(11):818-828
Objectives
The study was done to evaluate the efficacy of optical coherence tomography (OCT), to detect and analyze the microdamage occurring around the microimplant immediately following its placement, and to compare the findings with micro-computed tomography (μCT) images of the samples to validate the result of the present study.Methods
Microimplants were inserted into bovine bone samples. Images of the samples were obtained using OCT and μCT. Visual comparisons of the images were made to evaluate whether anatomical details and microdamage induced by microimplant insertion were accurately revealed by OCT.Results
The surface of the cortical bone with its anatomical variations is visualized on the OCT images. Microdamage occurring on the surface of the cortical bone around the microimplant can be appreciated in OCT images. The resulting OCT images were compared with the μCT images. A high correlation regarding the visualization of individual microcracks was observed. The depth penetration of OCT is limited when compared to μCT.Conclusions
OCT in the present study was able to generate high-resolution images of the microdamage occurring around the microimplant. Image quality at the surface of the cortical bone is above par when compared with μCT imaging, because of the inherent high contrast and high-resolution quality of OCT systems. Improvements in the imaging depth and development of intraoral sensors are vital for developing a real-time imaging system and integrating the system into orthodontic practice.537.
The increase in online graduate programs and the online mentoring of student research have led to the need to identify challenges faced by online mentees and successful strategies used by online mentors during the dissertation process. Based on semistructured interviews with ten graduates, strategies for online mentoring and areas of support valued by online doctoral students during the dissertation process are presented in this article. 相似文献
538.
Niraj Kumar 《Journal of Higher Education Policy & Management》2016,38(6):676-689
The objectives of this paper were to explore the existing status of agricultural higher education in India, application of marketing concepts in similar institutions and to find the most appropriate marketing concept to make agricultural higher education more competitive. Extensive searches of relevant agricultural education, business management and higher educational data bases were made. It was found that agricultural higher education in India is stagnant and is facing an identity crisis among its stakeholders. Marketing theories and concepts which are now being applied in higher education across the globe have not been thought of in the context of agriculture education. A review of the literature suggested that considering the objectives, the multiplicity of stakeholders and the nature of public-funded agricultural education, marketing orientation would be most appropriate. Based on the experiences of similar institutions, the paper suggests a three-level strategy for the implementation of marketing orientation in institutions of agricultural higher education. 相似文献
539.
Cut‐scores were set by expert judges on assessments of reading and listening comprehension of English as a foreign language (EFL), using the bookmark standard‐setting method to differentiate proficiency levels defined by the Common European Framework of Reference (CEFR). Assessments contained stratified item samples drawn from extensive item pools, calibrated using Rasch models on the basis of examinee responses of a German nationwide assessment of secondary school language performance. The results suggest significant effects of item sampling strategies for the bookmark method on cut‐score recommendations, as well as significant cut‐score judgment revision over cut‐score placement rounds. Results are discussed within a framework of establishing validity evidence supporting cut‐score recommendations using the widely employed bookmark method. 相似文献
540.