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Search Results: 1 - 10 of 223617 matches for " and R Rabindran "
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Preliminary Studies on Force/Motion Control of Intelligent Mechanical Systems
Dinesh Rabindran
Computer Science , 2014,
Abstract: To rationalize the relatively high investment that industrial automation systems entail, research in the field of intelligent machines should target high value functions such as fettling, die-finishing, deburring, and fixtureless manufacturing. For achieving this goal, past work has concentrated on force control algorithms at the system level with limited focus on performance expansion at the actuator level. We present a comprehensive literature review on robot force control, including algorithms, specialized actuators, and robot control software. A robot force control testbed was developed using Schunk's PowerCube 6-DOF Arm and a six-axis ATI force/torque sensor. Using parameter identification experiments, manipulator module inertias and the motor torque constant were estimated. Experiments were conducted to study the practical issues involved in implementing stable contact transitions and programmable endpoint impedance. Applications to human augmentation, virtual fixtures, and teleoperation are discussed. These experiments are used as a vehicle to understand the performance improvement achievable at the actuator level. The approach at UTRRG has been to maximize the choices within the actuator to enhance its intelligence. Drawing on this 20-year research history in electromechanical actuator architecture, we propose a new concept that mixes two inputs, distinct in their velocity ratios, within the same dual actuator called a Force/Motion Actuator (FMA). Detailed kinematic and dynamic models of this dual actuator are developed. The actuator performance is evaluated using simulations with an output velocity specification and resolving input trajectories using a minimum-norm solution. It is shown that a design choice of 14:1 motion scaling between the two inputs results in good sensitivity to output force disturbances without compromising velocity tracking performance.
Effect of substrate media on virulence of Fusarium pallidoroseum: a potential bioherbicide for Parthenium management
Indian Phytopathology , 2012,
Abstract: Aggressiveness of the pathogen was influenced by the nutritional status of the substrate medium. F. pal/idoroseum, grown on Coon's medium had greater biomass production with very good sporulation and was proved to be highly pathogenic on parthenium plant and its
Marker Assisted Selection for Leaf Blast Disease resistance and other yield traits in rice (Oryza sativa L.) using RAPD Markers
Immanuel Selvaraj. C, , Pothiraj Nagarajan, K. Thiyagarajan, M Bharathi, and R Rabindran
Electronic Journal of Plant Breeding , 2011,
Abstract: A segregating population of 220 F2 individuals was developed by raising the selfed F1 seeds of a single hybrid plant, White Ponnix Moroberekan. Two hundred and twenty F3 families were phenotyped for blast resistance under artificial condition. Bulksegregantanalysis resulted in the identification of 12 leaf blast resistant phenotype specific RAPD markers. Mapping survey wasdone with seven RAPD primers which co-segregated in BSA. Twelve RAPD markers were scored in the F2 mapping population.Out of 12 marker loci, 11 marker loci (91.97 per cent) fitted into the expected segregation ratio of 3:1 based on χ2- test at 0.05per cent probability value. One way ANOVA was performed to identify the marker phenotype association and this resulted in theidentification of seven RAPD markers linked to three traits viz., leaf blast resistance (OPBB 5258, OPBB 5194, OPAL 16940 andOPBD 12680), five markers for GPT and one marker for grain yield per plant.
Genetic diversity analysis aiding in selection of parents by RAPD markers in rice (Oryza sativa L)
Immanuel Selvaraj. C, Pothiraj Nagarajan, K. Thiyagarajan, M Bharathi, and R Rabindran
Electronic Journal of Plant Breeding , 2011,
Abstract: Genetic diversity among 26 rice genotypes was investigated using RAPD markers. The genotypes were screened for the leaf blastdisease reaction at two different environments. The average number of alleles amplified per primer was 9.03. Average number ofpolymorphic bands per primer was 6.80 with average polymorphism information content (PIC) of 0.264. Clustering based ondendrogram revealed two major clusters and 5 sub clusters. Principal Coordinate Analysis (PCoA) revealed three major groups.The first coordinate does not discriminate any of the genotypes based on the geographical origin, but the second and thirdcoordinates differentiated South East Asian and South Asian genotypes clearly. Genetic diversity analysis of rice genotypes withRAPD marker system and phenotypic screening for blast resistance revealed that White Ponni (susceptible) and Moroberekan(resistant) were one among the genetically distant and contrasting parents for leaf blast resistance. There is no cleardiscrimination of the markers to distinguish leaf blast resistant and susceptible genotypes into separate clusters by the principalcoordinate analysis.
Study of the Dynamic Coupling Term (μ) in Parallel Force/Velocity Actuated Systems
Dinesh Rabindran,Delbert Tesar
Computer Science , 2014,
Abstract: Presented in this paper is an actuator concept, called a Parallel Force/Velocity Actuator (PFVA), that combines two fundamentally distinct actuators (one using low gear reduction or even direct drive, which we will call a Force Actuator (FA) and the other with a high reduction gear train that we will refer to as a Velocity Actuator (VA)). The objective of this work is to evaluate the effect of the relative scale factor, RSF, (ratio of gear reductions) between these inputs on their dynamic coupling. We conceptually describe a Parallel Force/Velocity Actuator (PFVA) based on a Dual-Input-Single- Output (DISO) epicyclic gear train. We then present an analytical formulation for the variation of the dynamic coupling term w.r.t. RSF. Conclusions from this formulation are illustrated through a numerical example involving a 1-DOF four-bar linkage. It is shown, both analytically and numerically, that as we increase the RSF, the two inputs to the PFVA are decoupled w.r.t. the inertia torques. This understanding can serve as an important design guideline for PFVAs. The paper also presents two limitations of this study and suggests future work based on these caveats.
Deletions within the 3' Non-Translated Region of Alfalfa mosaic virus RNA4 Do Not Affect Replication but Significantly Reduce Long-Distance Movement of Chimeric Tobacco mosaic virus
Gourgopal Roy,Oleg Fedorkin,Masaaki Fujiki,Marina Skarjinskaia,Elisabeth Knapp,Shailaja Rabindran,Vidadi Yusibov
Viruses , 2013, DOI: 10.3390/v5071802
Abstract: Alfalfa mosaic virus (AlMV) RNAs 1 and 2 with deletions in their 3' non?translated regions (NTRs) have been previously shown to be encapsidated into virions by coat protein (CP) expressed from RNA3, indicating that the 3' NTRs of RNAs 1 and 2 are not required for virion assembly. Here, we constructed various mutants by deleting sequences within the 3' NTR of AlMV subgenomic (sg) RNA4 (same as of RNA3) and examined the effect of these deletions on replication and translation of chimeric Tobacco mosaic virus (TMV) expressing AlMV sgRNA4 from the TMV CP sg promoter (Av/A4) in tobacco protoplasts and Nicotiana benthamiana plants. While the Av/A4 mutants were as competent as the wild-type Av/A4 in RNA replication in protoplasts, their encapsidation, long-distance movement and virus accumulation varied significantly in N. benthamiana. These data suggest that the 3' NTR of AlMV sgRNA4 contains potential elements necessary for virus encapsidation.
Discovery of Novel AKT Inhibitors with Enhanced Anti-Tumor Effects in Combination with the MEK Inhibitor
Melissa Dumble, Ming-Chih Crouthamel, Shu-Yun Zhang, Michael Schaber, Dana Levy, Kimberly Robell, Qi Liu, David J. Figueroa, Elisabeth A. Minthorn, Mark A. Seefeld, Meagan B. Rouse, Sridhar K. Rabindran, Dirk A. Heerding, Rakesh Kumar
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100880
Abstract: Tumor cells upregulate many cell signaling pathways, with AKT being one of the key kinases to be activated in a variety of malignancies. GSK2110183 and GSK2141795 are orally bioavailable, potent inhibitors of the AKT kinases that have progressed to human clinical studies. Both compounds are selective, ATP-competitive inhibitors of AKT 1, 2 and 3. Cells treated with either compound show decreased phosphorylation of several substrates downstream of AKT. Both compounds have desirable pharmaceutical properties and daily oral dosing results in a sustained inhibition of AKT activity as well as inhibition of tumor growth in several mouse tumor models of various histologic origins. Improved kinase selectivity was associated with reduced effects on glucose homeostasis as compared to previously reported ATP-competitive AKT kinase inhibitors. In a diverse cell line proliferation screen, AKT inhibitors showed increased potency in cell lines with an activated AKT pathway (via PI3K/PTEN mutation or loss) while cell lines with activating mutations in the MAPK pathway (KRAS/BRAF) were less sensitive to AKT inhibition. Further investigation in mouse models of KRAS driven pancreatic cancer confirmed that combining the AKT inhibitor, GSK2141795 with a MEK inhibitor (GSK2110212; trametinib) resulted in an enhanced anti-tumor effect accompanied with greater reduction in phospho-S6 levels. Taken together these results support clinical evaluation of the AKT inhibitors in cancer, especially in combination with MEK inhibitor.
Power Aware Routing Protocol (PARP) for Wireless Sensor Networks  [PDF]
R. Prema, R. Rangarajan
Wireless Sensor Network (WSN) , 2012, DOI: 10.4236/wsn.2012.45019
Abstract: Several wireless sensor network applications ought to decide the intrinsic variance between energy efficient communication and the requirement to attain preferred quality of service (QoS) such as packet delivery ratio, delay and to reduce the power consumption of wireless sensor nodes. In order to address this challenge, we propose the Power Aware Routing Protocol (PARP), which attains application-specified communication delays at low energy cost by dynamically adapting transmission power and routing decisions. Extensive simulation results prove that the proposed PARP attains better QoS and reduced power consumption.
Studies on Dissolution Behaviour of Nanoparticulate Curcumin Formulation  [PDF]
R. Ravichandran
Advances in Nanoparticles (ANP) , 2013, DOI: 10.4236/anp.2013.21010

Curcumin is the main biologically active phytochemical compound of turmeric that has been widely used by ancient cultures throughout Asia. However the dissolution rate limited absorption and pre-absorption degradation limits its use as a potential therapeutic. In this study an attempt has been made to overcome the above limitations by curcumin delivery through nanotechnology. Nanocurcumin solid dosage formulations were prepared and studied for its dissolution behaviour. Considerable improvement in the dissolution behavior was observed in the drug nanocrystal-loaded solid dosage forms. This is expected to enhance the bioavailability of poorly soluble medicinal herbs such as turmeric in the body.

Pharmacokinetic Study of Nanoparticulate Curcumin: Oral Formulation for Enhanced Bioavailability  [PDF]
R. Ravichandran
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2013, DOI: 10.4236/jbnb.2013.43037

Curcumin, a bioactive component of turmeric, which is a commonly used spice and nutritional supplement, is isolated from the rhizomes of Curcuma longa Linn. (Zingiberaceae). In recent years, the potential pharmacological actions of Curcumin in inflammatory disorders, cardiovascular disease, cancer, Alzheimer’s disease and neurological disorders have been shown. However, the clinical application of Curcumin is severely limited by its main drawbacks such as instability, low solubility, poor bioavailability and rapid metabolism. Multifarious nanotechnology-based drug delivery systems for Curcumin including liposomes, polymeric nanoparticles, solid lipid nanoparticles, micelles, nanogels, nanoemulsions, complexes and dendrimer/dimer, have been attempted to enhance the oral bioavailability, biological activity or tissue-targeting ability of Curcumin. We attempted the nanosuspensions based delivery of curcumin. Nanonisation renders curcumin completely dispersible in aqueous media. To enhance the curcumin absorption by oral administration, nanoparticulate solid oral formulation of curcumin was prepared by us and the resulting capsule was then examined for its efficiency on bioavailability in Male Wistar rats at a dose of 100 mg curcumin/kg body weight and the pharmacokinetic parameters were compared to those of normal curcumin powder and a commercial curcumin capsule CUR-500. The bio-distribution of curcumin in organs of rat was also studied. Nanoparticulation significantly raised the curcumin concentration in selective organs in the body. The results obtained provide promising results for nanoparticulate Curcumin to improve its biological activities. Enhanced bioavailability of curcumin in the form of nanoparticle is likely to bring this promising natural product to the forefront of therapeutic agents for treatment of human disease. The available information also strongly suggests that nano-formulation of ingredients such as curcumin may be used as a novel nutrient delivery system too.

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