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Somatic embryogenesis in wild relatives of cotton (Gossypium Spp.)   总被引:2,自引:0,他引:2  
Wild cotton species can contribute a valuable gene pool for agronomically desirable cultivated tetraploid cultivars. In order to exploit diploid cotton a regeneration system is required to achieve transformation based goals. The present studies aimed at optimizing the conditions for regeneration of local varieties as well as wild species of cotton. Different callus induction media were tested with varying concentrations of hormones in which sucrose was used as nutritional source. Different explants (hypocotyls, cotyledon, root) were used to check the regeneration of both local cotton plants and wild relatives using T & G medium, BAP medium, CIM medium, EMMS medium, and cell suspension medium. Different stages of embryogenicity such as early torpedo stage, late torpedo stage, heart stage, globular stage and cotyledonary stage were observed in wild relatives of cotton. The results of this study pave the way for establishing future transformation methods.  相似文献   
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The present study was undertaken to evaluate antidiabetic and antioxidant activities of Cassia tora (C. tora) seeds extract against streptozotocin induced diabetes in experimental rats to scientifically validate its use against diabetes. Ethanolic extract of C. tora seeds extract and standard drug (glibenclamide) prepared in aqueous gum acacia (2 %, w/v) suspension and fed orally to streptozotocin induced male adult diabetic rats of Charles Foster strain for 15 days. Biochemical parameters in normal, diabetic control, standard (600 μg/kg bw p.o.) and treated (500 mg/kg bw p.o.) animal groups were quantified and compared. Treatment of streptozotocin induced diabetic rats with ethanolic seeds extract caused significant (p < 0.001) reduction in blood glucose (270–220 mg/dl), total cholesterol (140–104 mg/dl), triglyceride (149–99 mg/dl), phospholipids (100–74 mg/dl), free fatty acid (2.39–2.00 μmol/l), lipid peroxide (9–5.63 nmol MDA/dl) and significantly increased post heparin lipolytic activity (11–14 nmol FFA released/h/l plasma) (p < 0.001). Furthermore, the seeds extract (100–400 μg) when tested for its antioxidant activity in vitro, showed significant (p < 0.001) inhibition in the generation of super oxide anions in enzymic system a (46–37, 33, 23, 21 nmol uric acid formed/min), in enzymic system b (113–91, 77, 60, 51 nmol formazon formed/min), non-enzymic system (324–230, 211, 161, 141 nmol uric acid formed/min) and hydroxyl radicals in enzymic system (544–501, 411, 319, 291 nmol 2,3-dihydroxybenzoate formed/h) and non-enzymic system (28–21, 17, 14, 12). The results of the present study demonstrated antidiabetic, antidyslipidemic and antioxidant activities of C. tora seeds which could help in prevention of diabeticdyslipidemia and related complications.  相似文献   
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ABSTRACT

Science educators demonstrated that students’ framings – their expectations of what is going on – influence how they participate, and what science knowledge they reveal, in clinical interviews. This paper complements research that explores how interviewers are likely to affect student framings, by exploring how subtler interactions can lead students to change their framings, and thus their behaviour, in unexpected ways. We present data from interviews with two students, Sarah and Omar, as they reasoned about evaporation and condensation. Sarah demonstrated spontaneous changes in how she participated over the course of the interview, whereas Omar demonstrated subtler changes that existing methods may not capture. These changes affected the nature of scientific knowledge and reasoning demonstrated by each participant, but could not be fully explained by response to interviewer behaviour. We use the constructs of footing and positioning theory to examine how students participated during the interviews, and how this affected the ways they demonstrated knowledge and reasoning about the interview topic. In both cases, footing and positioning theory allowed us to better understand the dynamic ways students engage in the interview. This paper contributes new methods for analysing complex interview dynamics, and suggests situations for which such methods are necessary.  相似文献   
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Trace metals are beneficial nutrient materials that act as essential cofactors in physiological processes. Recent evidence suggests that increase or decrease in certain trace metals may be related with risk and development of chronic diseases such as cancer. This study analyzed some trace elements level in hair and nail of patients with stomach cancer, and compared with their level in healthy controls. Trace elements (Cu, Fe, K, Li, Mg, Mn, Na, P, Se, Sr and Zn) are estimated in hair and nail of the 73 cancer patients and 83 controls by atomic absorption spectrophotometric method. The levels of Cu, K, Li, P and Se in hair and nail samples, were significantly higher in cases than controls. Levels of Mg and Sr were significantly lower in cases than controls. Fe level in hair samples was significantly higher in cases than controls. The mean concentrations of Fe, Se and P significantly increased with increasing cancer stage in the hair of patients. The average concentration of k also significantly increased with increasing cancer stage in the nail of patients. The results of our study show that there is an association between the increase in Cu, K, Li, P, Se and Fe, and stomach cancer development. Our results reveal that the increase in the trace elements could be a potential diagnostic marker to predict cancer progression and its etiology.  相似文献   
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Abstract

This study examines the promotion and knowledge of online patent literature search among students, librarians, and instructors to enhance university scientific output in Zanzibar. The study was guided by four key questions: What is the level of awareness of students, instructors and library staff about patent documents as source of information? To what extent do students and instructors access online patent databases? What is the library experience in training students about online patent literature searching?, and what are the challenges facing library and instructors in promoting patent literature search? The study used survey approach whereby questionnaire and interview were used to collect data. The recent literatures regarding online patent literature searching were also critically reviewed. A survey was conducted at two Universities in Zanzibar namely the State University of Zanzibar and Zanzibar University, whereby 20 library staff, 10 instructors and 140 undergraduate students from the School of Computing and the Faculty of Engineering were involved in this study. The findings show that more than three quarters of respondents were either partially aware or not aware at all about the existence of free online patent databases. Likewise, the majority of students had no enough skills of patent literature searching. However, usually the library organizes training on general online literature searching skills but patent literature searching was not effectively taught and a big challenge observed in this study regarding promotion of patent literature searching is inadequate patent searching skills among library and instructors. Based on the findings, the study proposed several recommendations to rectify the existing problem.  相似文献   
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