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利用悬浮培养进行葡萄细胞抗寒性筛选的研究

园艺学报 1992年第2期19卷 135-139页

作者：张明鹏 rajashekar C.B. 仲恺农业技术学院广州510225 堪萨斯州立大学

利用细胞悬浮培养和TTC分析法,进行葡萄细胞抗寒性筛选的研究结果表明,3个供试品种,未经低温筛选的细胞低温致死温度为-3℃左右。经过-3至-7℃人工低温分级筛选,可以筛选出低温致死温度在-5、-6和-7℃左右的抗寒细胞系。在-3至-7℃范围... 详细信息

利用细胞悬浮培养和TTC分析法,进行葡萄细胞抗寒性筛选的研究结果表明,3个供试品种,未经低温筛选的细胞低温致死温度为-3℃左右。经过-3至-7℃人工低温分级筛选,可以筛选出低温致死温度在-5、-6和-7℃左右的抗寒细胞系。在-3至-7℃范围内,筛选温度越低,所获抗寒细胞系的抗寒性越强,其低温致死温度也越低。当筛选温度下降至-8℃时,3个供试品种的细胞残存量都极微,没有筛选出抗寒细胞系。

关键词：葡萄抗寒性筛选细胞悬浮培养

Fabrication and Characterization of Glass Fiber with SiC Reinforced Polymer Composites

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Open Journal of Composite Materials 2022年第1期12卷 16-29页

作者： rajashekar Reddy Palle Jens Schuster Yousuf Pasha Shaik Monis Kazmi Department of Applied Logistics and Polymer Sciences University of Applied Sciences Kaiserslautern Institute for Plastics Engineering West Pfalz (IKW) Pirmasens Germany

Glass Fiber Reinforced Polymeric (GFRP) Composites are most commonly used as bumpers for vehicles, electrical equipment panels, and medical devices enclosures. These materials are also widely used for structural applications in aerospace, automotive, and in providing alternatives to traditional metallic materials. The paper fabricated epoxy and polyester resin composites by using silicon carbide in various proportions along with GFRP. The hand lay-up technique was used to fabricate the laminates. To determine the properties of fabricated composites, the tensile, impact, and flexural tests were conducted. This method of fabrication was very simple and cost-effective. Their mechanical properties like yield strength, yield strain, Young’s modulus, flexural modulus, and impact energy were investigated. The mechanical properties of the GFRP composites were also compared with the fiber volume fraction. The fiber volume fraction plays a major role in the mechanical properties of GFRP composites. Young’s modulus and tensile strength of fabricated composites were modelled and compared with measured values. The results show that composites with epoxy resin demonstrate higher strength and modulus compared to composites with polyester resin.

关键词： Polymer Matrix Composite Epoxy and Polyester Resins Silicon Carbide Glass Fibers Hand Lay-Up Technique Modelling

Hydrogen Peroxide Alleviates Hypoxia during Imbibition and Germination of Bean Seeds (<i>Phaseolus vulgaris</i>L.)

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American Journal of Plant Sciences 2014年第24期5卷 3572-3584页

作者： C. B. rajashekar Kwang-Hyun Baek Department of Horticulture Forestry and Recreation Resources Kansas State University Manhattan KS USA

Bean seeds (Phaseolus vulgaris L. cv. Tendergreen) were imbibed in water to examine the effects of hypoxia during imbibition and subsequent germination. Hypoxic conditions occurred when seeds were imbibed in water for 24 h or longer and resulted in severe reduction of hypocotyl elongation and stem growth during subsequent germination under non-limiting oxygen conditions. Under continued hypoxic conditions, bean seeds failed to germinate, however, this was reversed in the presence of hydrogen peroxide (20 mM) in the medium. Furthermore, imbibition of seeds in the presence of hydrogen peroxide overcame the adverse hypoxic effects on hypocotyl elongation and stem growth. Exogenous hydrogen peroxide increased the dissolved oxygen levels in the germinating medium, and catalase and transition metal ions such as Fe2+, Cu2+ and Mn2 helped to facilitate the production of oxygen from hydrogen peroxide. In these catalysts, catalase played a major role in the decomposition of hydrogen peroxide as demonstrated by the use of a catalase inhibitor, 3-amino-1, 2, 4-triazole, which reversed the positive effects produced by hydrogen peroxide on germination of seeds under hypoxic conditions. The results show that imbibition is sensitive to oxygen deficits which affect subsequent hypocotyl growth and seedling performance. The adverse effects of hypoxia on germination of bean seeds can be overcome by exogenous hydrogen peroxide.

关键词： Aminotriazole Anoxia Catalase Hydrogen Peroxide Hypoxia Phaseolus vulgaris Seed Germination

Exogenous Vitamin K3 and Peroxides Can Alleviate Hypoxia in Bean Seedlings (<i>Phaseolus vulgaris</i>L.)

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American Journal of Plant Sciences 2014年第22期5卷 3396-3407页

作者： C. B. rajashekar Jinmin Fu Anju Giri Department of Horticulture Forestry and Recreation Resource Kansas State University Manhattan USA Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture Wuhan Botanical Garden Chinese Academy of Sciences Wuhan China

Oxygen limiting conditions are a common occurrence in root zones of most crop plants and can adversely affect nearly all aspects of plant growth and development including its survival. The objective of this study was to determine the effectiveness of a novel redox cycling agent, vitamin K3, and various peroxides including hydrogen peroxide, calcium peroxide and magnesium peroxide in alleviating the effects of hypoxia in bean seedlings grown in nutrient culture. All the anti-hypoxic agents including vitamin K3 had a positive impact on the overall growth of bean seedlings under hypoxic conditions, but their responses were variable depending on the concentration. With regard to shoot growth, vitamin K3 (5 μM) increased the leaf area significantly, by more than 58% over the hypoxic control plants and produced the highest stem fresh weight similar to calcium peroxide (20 μM) and magnesium peroxide (10 μM). In addition, the use of vitamin K3 resulted in the highest accumulation of chlorophyll (chla + chlb) in the leaves, an increase of nearly two-fold over the hypoxic control plants. Furthermore under hypoxia, calcium peroxide (20 μM) and magnesium peroxide (10 μM) produced the highest leaf biomass (FW) followed by vitamin K3. Vitamin K3 (1 μM) also favored root growth in bean seedlings under hypoxia;it produced the largest increase in root length and root biomass (DW) similar to calcium peroxide and magnesium peroxide. Based on the overall shoot and root growth response of bean seedlings to various anti-hypoxic substances under hypoxic conditions, calcium peroxide, magnesium peroxide and vitamin K3 performed better than hydrogen peroxide. These findings show that vitamin K3 and peroxide salts are effective in alleviating hypoxic stress in bean seedlings and also, further highlight their potential for dealing with hypoxia in wide ranging situations.

关键词： Hypoxia Vitamin K3 Menadione Peroxides Beans

Organic Crop Management Enhances Chicoric Acid Content in Lettuce

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Food and Nutrition Sciences 2012年第9期3卷 1296-1302页

作者： Channa B. rajashekar Myung-Min Oh Edward E. Carey Department of Horticultural Science Chungbuk National University Cheongju Korea Department of Horticulture Forestry and Recreation Resources Kansas State University Manhattan KS USA International Potato Center Fumesua Kumasi Ghana

L- chicoric acid is a dominant phenolic compound in lettuce (Lactuca sativa L.) and has been shown to accumulate in response to many abiotic stresses and crop management practices. It is a potent inhibitor of human immunodeficiency virus (HIV-1) integrase needed for the replication of this virus and for the productive infection of the host cell. L- chicoric acid has been found to act synergistically in combination with anti-HIV drugs used for treating acquired immuno-deficiency disorder (AIDS). We show in this study that organic management practices increase the chicoric acid content by nearly 2-fold compared to conventional management practices while they did not have a significant effect on the overall accumulation of phenolic compounds and antioxidants. Similar increase was observed in quercetin-3-O-glucoside under organic management. In addition, pre-plant fertilization decreased the levels of many phenolic compounds including chicoric acid under organic management unlike under conventional management. However, organically managed crop without pre-plant fertilization had better growth and produced about 2.5 times higher yield and higher chicoric acid content than did the conventionally managed crop. Thus, the results show that long term organic crop management practices, but avoiding pre-plant fertilization, can significantly enhance the yield of antiretroviral agent chicoric acid in lettuce.

关键词： AIDS Antiretroviral Crop Production Practices HIV-1 Organic Fertilization Phytochemical

Supplemental UV-A and UV-B Affect the Nutritional Quality of Lettuce and Tomato: Health-Promoting Phytochemicals and Essential Nutrients

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American Journal of Plant Sciences 2021年第1期12卷 104-126页

作者： Myungjin Lee Cary Rivard Eleni Pliakoni Weiqun Wang C. B. rajashekar Department of Horticulture and Natural Resources Kansas State University Manhattan KS USA K-State Olathe Horticulture Research and Extension Center Olathe KS USA Department of Horticulture and Natural Resources Kansas State University Olathe KS USA Department of Food Nutrition Dietetics and Health Kansas State University Manhattan KS USA

UV radiation plays an important role not only in plant growth and development but also in the accumulation of essential nutrients and health-promoting phytochemicals in plants. The main objective of this study was to examine the effects of supplemental UV-A, UV-B, and UV-AB on the nutritional quality of lettuce (Lactuca sativa, cv. red leaf “New Red Fire” and green leaf “Two Star”) and tomato (Solanum lycopersicum L., cv. BHN-589) grown in a greenhouse. Supplemental UV radiation was provided by UV lamps 5 - 6 days prior to harvest. Supplemental UV-A produced higher accumulation of total phenolic compounds and higher antioxidant capacity in red leaf lettuce compared to other treatments. Overall, supplemental UV-A produced a stronger response than other UV treatments and control in the accumulation of many phenolic compounds including luteolin-7-glucoside, quecetin-3-glucoside, and apigenin-3-glucoside in red leaf lettuce. However, UV-B and UV-AB had a negative response in the accumulation of many phenolic compounds including chlorogenic acid, luteolin-7-glucoside, quercetin-3-glucoside, and apigenin-3-glucoside in both red and green leaf lettuce varieties. In tomato fruits, supplemental UV-A had no effect on their total phenolic concentration. However, supplemental UV-B radiation for 3 h or UV-AB radiation for 9 h exposure produced higher total phenolic concentration in the fruits compared to other supplemental UV treatments. Supplemental UV-AB (3 hexposure) was generally more effective than other UV treatments in increasing the accumulation of a number of phenolic compounds including chlorogenic acid, caffeic acid, chicoric acid, luteolin-7

关键词： Greenhouse Lettuce Micronutrients Nutritional Quality Phytochemicals Spectral Quality Tomato UV-A and UV-B

The Effect of Supplemental Blue, Red and Far-Red Light on the Growth and the Nutritional Quality of Red and Green Leaf Lettuce

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American Journal of Plant Sciences 2019年第12期10卷 2219-2235页

作者： Myungjin Lee Jingwen Xu Weiqun Wang C. B. rajashekar Department of Horticulture and Natural Resources Kansas State University Manhattan KS USA Department of Food Nutrition Dietetics and Health Kansas State University Manhattan KS USA

Spectral quality of radiation has a major impact on the growth, development and nutritional quality of crops. The effect of supplemental radiation (blue, red and far-red) on the growth and nutritional quality with regard to health-promoting phytochemical and micronutrient composition of two lettuce (Lactuca sativa) varieties (red leaf “New Red Fire” and green leaf “Two Star”) was studied. Supplemental radiation was provided by blue (450 nm), red (660 nm) or far-red (730 nm) LEDs against a background of white light (fluorescent lighting, PAR;270 μmol/m2/s) in a growth chamber study. All the supplemental radiation treatments increased dry shoot biomass in both varieties. However, supplemental far-red radiation increased both fresh and dry shoot biomass in both varieties. In addition, supplemental far-red radiation produced distinct morphological characteristics in lettuce plants. It produced the largest shoot biomass, bigger and taller plants, fewer leaves but with larger leaf area compared to the control, similar to the shade avoidance response. With regard to the accumulation of phytochemicals, supplemental blue radiation enhanced the total phenolic compound concentration in both varieties. In addition, supplemental blue radiation sharply increased the accumulation of several phenolic compounds in green leaf lettuce including chlorogenic acid, chicoric acid, rutin, kaempferol, luteolin and apigenin. For example, the leaf concentration of rutin in green leaf lettuce increased by 20-fold under supplemental blue radiation. Similarly, supplemental red radiation increased the concentration of many of these phenolic compounds in red leaf lettuce. However, supplemental far-red radiation had an inhibitory effect on the accumulation of chlorogenic acid, chicoric acid, rutin and kaempferol in red leaf lettuce. While supplemental radiation did not affect the accumulation of most of the micronutrients, it had a negative impact on the accumulation of some micronutrients, the res

关键词： LEDs Lettuce Micronutrients Nutritional Quality Phytochemicals Spectral Quality

Polytetrafluoroethylene Patch versus Autologous Pericardial Patch for Right Ventricular Outflow Tract Reconstruction in Patients with Tetralogy of Fallot

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World Journal of Cardiovascular Surgery 2017年第3期7卷 41-53页

作者： Sachin Talwar Intekhab Alam Vishnubhatla Srreenivas Palleti rajashekar Sivasubramanian Ramakrishnan Shiv Kumar Choudhary Balram Airan Department of Cardiothoracic and Vascular Surgery All India Institute of Medical Sciences New Delhi India Biostatistics All India Institute of Medical Sciences New Delhi India Cardiology All India Institute of Medical Sciences New Delhi India

Objective: For patients of TOF with pulmonary annular hypoplasia, reconstruction of right ventricular outflow tract (RVOT) often requires a trans annular patch (TAP). The present study aims to compare the outcomes of TOF repair using Polytetrafluoroethylene (PTFE) patch versus autologous glutaraldehyde fixed pericardial patch for RVOT reconstruction. Materials and methods: 103 consecutive patients undergoing TOF repair in whom TAP was required were randomized into two groups: Group I (pericardial patch), Group II (PTFE patch). Postoperative outcomes in terms of postoperative heart rhythm, duration of mechanical ventilation, mediastinal and pleural drainage, length of stay in intensive care unit (ICU) and hospital mortality were assessed. A separate team of cardiologists independently evaluated pre- and post-operative gradients across the RVOT, degree of pulmonary insufficiency, right ventricular systolic function. Results: There were no significant differences between the two groups in terms of the incidence of postoperative arrhythmias, duration of mechanical ventilation, length of intensive care unit or hospital stay. The requirement of inotropes was no different in the PTFE patch group as compared with the pericardial patch group (16.84 ± 7.04 vs. 17.90 ± 6.71, median 19 vs. 20, p = 0.825). The re-exploration rate was higher in the PTFE group as compared with the pericardial patch group (6 vs. 1). Postoperative Echocar-diography revealed no differences in the RV systolic function between the two groups before discharge. Conclusion: In patients undergoing TOF repair, using a PTFE patch yields comparable results. However, the efficacy of PTFE will only be established once;mid-term and long-term results are available.

关键词： Tetralogy of Fallot Right Ventricular Outflow Tract Patch Material

Ivabradine—The Final Crusader for Postoperative Junctional Ectopic Tachycardia, a Case Report with Literature Review

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World Journal of Cardiovascular Surgery 2019年第8期9卷 73-82页

作者： Manoj Kumar Sahu Harsha Vardhan Niraghatam Nikhil Bansal Sarvesh Pal Singh Palleti rajashekar Shiv Kumar Choudhary Department of Cardiothoracic and Vascular Surgery CN Centre All India Institute of Medical Sciences New Delhi India

Background: Junctional ectopic tachycardia (JET) is one troublesome supraventricular arrhythmia in postoperative pediatric cardiac surgical patients. Unless treated timely and effectively it may lead to morbidity and even mortality. Aim: To understand the role of Ivabradine in the treatment of JET in postoperative pediatric cardiac surgical patients. Case: We present a postoperative case of complete repair of Tetralogy of Fallot who was in normal sinus rhythm in the preoperative period and developed JET 4 hours later in postoperative period which was persistent despite measures to optimize the internal milieu of the body and conventional antiarrhythmics, that was successfully treated with Ivabradine at a dose of 0.05 mg/kg/12 hourly. Conclusion: Ivabradine can be used to successfully treat postoperative JET in cases ofrefractory to other antiarrhythmic drugs like Digoxin and Amiodarone.

关键词： Tetralogy of Fallot Junctional Ectopic Tachycardia Ivabradine