oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Search Results: 1 - 10 of 1259 matches for " Leena Tripathi "
All listed articles are free for downloading (OA Articles)
Page 1 /1259
Display every page Item
Genetic engineering for improvement of Musa production in Africa
Leena Tripathi
African Journal of Biotechnology , 2003,
Abstract: Bananas and plantains (Musa sp.) are the most important staple food and source of carbohydrates in many countries of Africa. The production is often constrained by many pests and diseases. In order to augment conventional breeding and to avoid constraints imposed by some pests and pathogens, transgenic approaches are being considered. The development of transgenic Musa plants has been achieved recently using the microprojectile bombardment procedure or Agrobacterium-mediated transformation. The transgenic approach shows potential for the genetic improvement of the crop using a wide set of transgenes currently available which may confer resistance to nematode pests, fungal, bacterial and viral diseases. This article discusses the applications of genetic engineering for the enhancement of Musa production.
Role of biotechnology in medicinal plants
Leena Tripathi, Jaindra Nath Tripathi
Tropical Journal of Pharmaceutical Research , 2003,
Abstract: Medicinal plants are the most important source of life saving drugs for the majority of the world's population. The biotechnological tools are important to select, multiply and conserve the critical genotypes of medicinal plants. In-vitro regeneration holds tremendous potential for the production of high-quality plant-based medicine. Cryopreservation is long-term conservation method in liquid nitrogen and provides an opportunity for conservation of endangered medicinal plants. In-vitro production of secondary metabolites in plant cell suspension cultures has been reported from various medicinal plants. Bioreactors are the key step towards commercial production of secondary metabolites by plant biotechnology. Genetic transformation may be a powerful tool for enhancing the productivity of novel secondary metabolites; especially by Agrobacterium rhizogenes induced hairy roots. This article discusses the applications of biotechnology for regeneration and genetic transformation for enhancement of secondary metabolite production in-vitro from medicinal plants.
Strategies for resistance to bacterial wilt disease of bananas through genetic engineering
Leena Tripathi, Jaindra Nath Tripathi, WK Tushemereirwe
African Journal of Biotechnology , 2004,
Abstract: The livelihoods of millions of Ugandan farmers have been threatened by current outbreak of a banana bacterial wilt disease caused by Xanthomonas campestris pv. musacearum, which is very destructive and rapidly spreading in Uganda. Bananas are the highest value staple food and source of income for millions of people in this region. Economic impact of the disease is clear as a result of widespread destruction of banana, pre-harvest rotting of fruits, and a lack of farmers' ability to grow bananas in disease endemic areas. The disease attacks all varieties of banana, including East African Highland Bananas (EAHBs). No banana germplasm with bacterial wilt resistance has been identified. The transgenic approach shows potential for the genetic improvement of the crop using a wide set of transgenes currently available which may confer bacterial resistance. This article discusses the potential strategies to develop transgenic banana plants resistant to bacterial wilt disease. Key Words: Banana, bacterial wilt, genetic transformation, disease resistant. African Journal of Biotechnology Vol.3(12) 2004: 688-692
Agrobacterium-induced hypersensitive necrotic reaction in plant cells: a resistance response against Agrobacterium-mediated DNA transfer
Danladi Dada Kuta, Leena Tripathi
African Journal of Biotechnology , 2005,
Abstract: High necrosis and poor survival rate of target plant tissues are some of the major factors that affect the efficiency of Agrobacterium-mediated T-DNA transfer into plant cells. These factors may be the result of, or linked to, hypersensitive defense reaction in plants to Agrobacterium infection, which may involve the recognition of specific signals from the Agrobacterium that triggers the burst of reactive oxygen species at the infection site. Evidences of Agrobacterium-induced necrosis in target plant tissues and its link to reactive oxygen species are presented. Application of antioxidants, addition of acetosyringone and optimization of pre-culture conditions suppress the Agrobacterium-induced hypersensitive necrotic response in target plant tissues, thereby enhancing stable transformation.
FORMULATION AND EVALUATION OF FLOATING MATRIX TABLETS OF FAMOTIDINE USING NATURAL POLYMERS
Jagtap Leena S,Swami Seema P,Mali Prabha R,Tripathi Pallavi S
International Research Journal of Pharmacy , 2011,
Abstract: In the present investigation effervescent floating matrix tablets of famotidine are formulated to achieve gastric retention for a period of 8 to 10 hrs. Famotidine is H2 receptor antagonist widely prescribed in gastric ulcer, Duodenal ulcer, Zollinger Ellison syndrome & Gastro-esophageal reflux disease. Famotidine has low oral bioavailability of 35% & short biological half life of 2 – 3 hrs. This favors development of sustained release dosage form. Besides this, it is primarily absorbed from stomach. Local delivery increase stomach wall receptor site bioavailability and increase efficacy of drug to reduce acid secretion. Hence the principle of Floating drug delivery system was applied to improve systemic as well as local drug delivery. Natural polysaccharides such as xanthan gum and chitosan were used to achieve sustained release of the drug. Thus it can be concluded that floating matrix famotidine tablets so formulated achieved desired gastric retention for 8 to 10 hrs and sustained the drug release. Thus one tablet daily is sufficient to reduce gastric acidity as compared to conventional tablets in hyperacidity conditions.
Quantitative Digital Imaging of Banana Growth Suppression by Plant Parasitic Nematodes
Hugh Roderick, Elvis Mbiru, Danny Coyne, Leena Tripathi, Howard J. Atkinson
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0053355
Abstract: A digital camera fitted with a hemispherical lens was used to generate canopy leaf area index (LAI) values for a banana (Musa spp.) field trial with the aim of establishing a method for monitoring stresses on tall crop plants. The trial in Uganda consisted of two cultivars susceptible to nematodes, a plantain, Gonja manjaya and an East African Highland banana, Mbwazirume, plus a nematode resistant dessert banana, Yangambi km5. A comparative approach included adding a mixed population of Radopholus similis, Helicotylenchus multicinctus and Meloidogyne spp. to the soil around half the plants of each cultivar prior to field planting. Measurements of LAI were made fortnightly from 106 days post-planting over two successive cropping cycles. The highest mean LAI during the first cycle for Gonja manjaya was suppressed to 74.8±3.5% by the addition of nematodes, while for Mbwazirume the values were reduced to 71.1±1.9%. During the second cycle these values were 69.2±2.2% and 72.2±2.7%, respectively. Reductions in LAI values were validated as due to the biotic stress by assessing nematode numbers in roots and the necrosis they caused at each of two harvests and the relationship is described. Yield losses, including a component due to toppled plants, were 35.3% and 55.3% for Gonja manjaya and 31.4% and 55.8% for Mbwazirume, at first and second harvests respectively. Yangambi km5 showed no decrease in LAI and yield in the presence of nematodes at both harvests. LAI estimated by hemispherical photography provided a rapid basis for detecting biotic growth checks by nematodes on bananas, and demonstrated the potential of the approach for studies of growth checks to other tall crop plants caused by biotic or abiotic stresses.
Collaborative Meeting as an Integrative Mechanism in a Multinational Investment Project  [PDF]
Leena Pekkinen, Jaakko Kujala
Technology and Investment (TI) , 2014, DOI: 10.4236/ti.2014.51006
Abstract:

In multinational and complex projects that are often implemented by multiple organizations, the entire projects need to be divided into manageable subprojects. At the same time, all subprojects are needed to be kept aligned with the project goals and targets by integration and coordination. The purpose of this article is to study the role of a particular, work-shop type, collaborative meeting by utilizing the characteristics of an integrative information processing framework. A single case study method was used to observe the practices of collaborative meetings. This study contributes to the project management research by analysing how collaborative meeting practice can be used as a mechanism to reduce uncertainty and equivocality in a large investment project. The results of this study are two folds: Firstly, the case project’s collaborative meetings are described in detail; secondly, the perceived features and procedures of the collaborative meetings in the case project are illustrated showing the role of the collaborative meetings as an integrative tool. Moreover, the perceived integrative characteristics of the collaborative meetings reducing uncertainty and equivocality are presented. This study indicates that collaborative meeting is an integrative mechanism reducing uncertainty and equivocality in a large investment project context.

Risk Management in Project Networks: An Information Processing View  [PDF]
Leena Pekkinen, Kirsi Aaltonen
Technology and Investment (TI) , 2015, DOI: 10.4236/ti.2015.61005
Abstract: Increasingly, projects are executed by networks of organizations. The networked form of organization has many important implications for project risk management. Information processing theories introduce mechanisms for processing information inside organizations as well as among organizations to reduce the uncertainty and equivocality inherently present in international projects. This study aims to examine the risk management practices involved at a project network level through an empirical analysis of one complex large project network executed in a challenging institutional environment. With regard to network level risk management, the paper identifies eight formal information processing mechanisms for implementing risk management: (1) established rules and criteria for the selection of subcontractors at a global level, (2) specification of responsibilities in the contract, (3) formal risk sheet, (4) progress follow-up tool, (5) database for project information, (6) customer reporting system, (7) updated project plan after the project is delayed, and (8) country study team. Personal relationships between parties, personal commitment, experienced individuals, and face-to-face meetings are identified as informal information processing mechanisms used as measures of project risk management to reduce equivocality. We also elaborate the fitness of the mechanisms used for the contextual situations of the project network settings.
Use of Masonry Construction & Demolition Waste in Concrete  [PDF]
Tahir Kibriya, Leena Tahir
World Journal of Engineering and Technology (WJET) , 2017, DOI: 10.4236/wjet.2017.52017
Abstract: Massive amounts of brick waste are obtained from demolition of old buildings and structures around the world. With the increased stress on sustainable construction, and environmentally friendly materials and greener concreting practices, a large proportion of such waste bricks are crushed and mixed with normal aggregates for use in concrete. The performance of concrete containing waste brick aggregates partially replacing normal aggregates have not been investigated for their performance. This paper covers investigations carried out on concrete with such aggregates obtained from demolition waste and mixed with varying proportions of normal aggregates to produce concrete. Two types of crushed brick aggregates were mixed with gravel in the ratios of 30:70 and 40:60 by weight and specimen were cast for investigations. Two w/c ratios were investigated. Various tests were carried out to assess the compressive strength of cubes and cylinders of mixed aggregates concrete along with f1exural strength, stress/strain behavior, moduli of elasticity, ultrasonic pulse velocity determination, densities, surface absorption, shrinkage and frost resistance. The values obtained from these tests were compared with the values of concrete with normal aggregates (gravel) with similar w/c ratios. While the strength tests and durability tests more or less gave satisfactory results however the larger moisture absorption by the waste brick aggregates reduces the frost resistance capacity somewhat thereby care needs to be exercised in using these mixes in regions/areas susceptible to frost.
Sustainable Construction—High Performance Concrete Containing Limestone Dust as Filler  [PDF]
Tahir Kibriya, Leena Tahir
World Journal of Engineering and Technology (WJET) , 2017, DOI: 10.4236/wjet.2017.53034
Abstract: Massive amounts of limestone waste are produced by the stone processing industry worldwide. Generally, it is believed that 60% to 70% of the stone is wasted in processing in the form of fragments, powder and slurry out of which around 30% is in the form of fine powder [1]. This waste has no beneficial usage and poses environmental hazards. Use of this waste product in the construction industry can largely reduce the amount of waste to be disposed off by the local municipalities in addition to reducing large burden on the environment. Some basic research on use of limestone dust as cement/ concrete filler?has?been carried out in the recent past but high strength/ high performance concretes have not been investigated yet [2] [3]. The concrete industry is among the largest consumer of raw materials worldwide and has been investigated for use of various types of waste materials like crushed brick, rice husk and straw ash as either aggregates for concrete or as partial cement substitutes. Use of limestone dust as filler material in concrete can consume a huge amount of this waste material which has to be disposed off otherwise, creating large burden on the environment. This experimental study aimed at evaluating the properties of high performance concretes made from Portland cement, natural aggregates and sand. Limestone dust was added by replacing sand in the percentages of 10% and 20%. Wide ranging investigations covering most aspects of mechanical behavior and permeability were carried out for various mixes for compressive strengths of 60?N/mm2, 80?N/mm2 and 100?N/mm2.
Page 1 /1259
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.