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Search Results: 1 - 10 of 224241 matches for " Dwivedi R "
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Role of lipid peroxidation and trace metal in cataractogenesis
Dwivedi R,Partap V
Indian Journal of Ophthalmology , 1986,
Evaluation of the Accuracy of “Ottawa Ankle Rules” for Predicting Fractures in Acute Ankle and Midfoot Injuries
R Dwivedi,SB Ale
Journal of Universal College of Medical Sciences , 2014, DOI: 10.3126/jucms.v2i2.11166
Abstract: INTRODUCTION: Twisting injuries of ankle and foot are one of the most common injuries seen in emergency department and are the most common sports injuries. Almost all such cases are investigated by X-rays to rule out fractures, but clinically significant fractures are detected only in a small number of cases (approximately 15%). Ottawa Ankle Rules (OARs) are screening tools, applied in acute ankle and foot injuries to exclude those cases that are not likely to have fractures and thereby reduce the number of unnecessary X-rays. At the same time, all clinically significant fractures are included and not a single clinically significant fracture is missed when OARs are applied properly. This study was conducted to evaluate the accuracy of “Ottawa Ankle Rules” in our setup.
Frequency of Cyclonic Disturbances and Changing Productivity Patterns in the North Indian Ocean Region: A Study Using Sea Surface Temperature and Ocean Colour Data  [PDF]
Madhumita Tripathy, Mini Raman, R. M. Dwivedi, Ajai Ajai
International Journal of Geosciences (IJG) , 2012, DOI: 10.4236/ijg.2012.33052
Abstract: In recent years we are observing devastating cyclones like Nargis, Gonu, Sidr, Liala, Phet etc in the North Indian Ocean associated with heavy rains, thunderstorm, high tide and intense winds that caused shocking destructions in the coastal areas. As these are originating over the Ocean and propagating towards land, they also change physical property as well as biological structure of the Ocean. In recent years, several attempts were made to associate tropical cyclone trends with climate change resulting from green house warming. The studies have indicated an increase in intense cyclones in the Arabian Sea. Time series analysis of ocean colour data have revealed rapid and profound change in the productivity pattern over the last few years in the Arabian Sea that appears to be related to the warming trends being experienced over the Asian subcontinent. In view of the above, a study was carried out to examine the frequency of cyclonic disturbances in the Arabian Sea and the Bay of Bengal and its effect in modulating the productivity patterns. Data on the monthly and annual occurrences of tropical cyclones in the Bay of Bengal and the Arabian Sea were collected from 1908 to 2007 from SAARC Meteorological Research Centre and Indian Meteorological Department. Sea surface temperature (SST) from NOAA-AVHRR and phytoplankton biomass indexed as chlorophyll-a concentration from Sea WiFs for ten years (1998-2007) were used to study the physical and biological effects of cyclonic events in the Arabian Sea (AS) and the Bay of Bengal (BOB). Analysis of the monthly and annual occurrences of tropical cyclone reveals an increasing trend of cyclonic disturbances in the AS whereas there is a decreasing trend in the BOB in the last decade (1998-2007). SST analysis indicates decrease in monthly average SST by 1.5℃ to 1.75℃ in the AS and 1.5℃ to 1.25℃ in the BOB in the pre-monsoon season. Phytoplankton biomass was observed to increase by a factor of two after the passage of cyclone. Results of the ten year analysis and comparison with the climatology showed that frequent occurrence of cyclonic events that cause short term-nutrient enrichment of upper-stratified ocean resulting in enhanced biological productivity and perturbations in the otherwise stable and seasonally-varying ecological structure of the North Indian Ocean.
Oxidative stress in patients with laryngeal carcinoma
Dwivedi R,Raturi D,Kandpal N,Dwivedi R
Indian Journal of Cancer , 2008,
Abstract: Background : Cancer is a multifactorial disease. Repetitive cumulative damage of cellular organelles by oxy-free radicals are few of the important causative factors. Aim : To assess the role of oxidative stress in the laryngeal cancer patients in Indian population. Setting and Design : Case control study. Materials and Methods : Level of malondialdehyde (MDA) as a marker of oxidative stress was examined in large cohort of control (50) and laryngeal carcinoma patients (155) from North India. Both the controls and laryngeal carcinoma patients were smokers. Results : In control healthy subjects MDA levels were 0.102±0.07 (0.080- 0.303, 95% CI) n mol/ml, as compared to 0.329±0.16 (0.124-0.354, 95% CI) n mol/ml in the cases of laryngeal carcinoma patients. Three times higher serum MDA levels indicated that there was significant oxidative stress in the subjects having laryngeal carcinoma lesions. In addition patients with secondaries were having MDA levels of 0.4±0.02 (0.391-0.408 95% CI) n mol/ml, as compared to 0.57±0.03 (0.558-0.582 95% CI)n mol/ml in group of patients without secondaries. These two values were statistically significant as compared to control values (P< 0.01). Conclusion : These findings suggest that in case of laryngeal carcinoma patients, there is increase in the level of oxidative enzyme MDA. The oxidative stress might be due to the modulation of pro-oxidant or anti-oxidant systems in laryngeal carcinoma.
Phylogenetic inference under varying proportions of indel-induced alignment gaps
Bhakti Dwivedi, Sudhindra R Gadagkar
BMC Evolutionary Biology , 2009, DOI: 10.1186/1471-2148-9-211
Abstract: (1) In general, there was a strong – almost deterministic – relationship between the amount of gap in the data and the level of phylogenetic accuracy when the alignments were very "gappy", (2) gaps resulting from deletions (as opposed to insertions) contributed more to the inaccuracy of phylogenetic inference, (3) the probabilistic methods (Bayesian, PhyML & "MLε, " a method implemented in DNAML in PHYLIP) performed better at most levels of gap percentage when compared to parsimony (MP) and distance (NJ) methods, with Bayesian analysis being clearly the best, (4) methods that treat gapped sites as missing data yielded less accurate trees when compared to those that attribute phylogenetic signal to the gapped sites (by coding them as binary character data – presence/absence, or as in the MLε method), and (5) in general, the accuracy of phylogenetic inference depended upon the amount of available data when the gaps resulted from mainly deletion events, and the amount of missing data when insertion events were equally likely to have caused the alignment gaps.When gaps in an alignment are a consequence of indel events in the evolution of the sequences, the accuracy of phylogenetic analysis is likely to improve if: (1) alignment gaps are categorized as arising from insertion events or deletion events and then treated separately in the analysis, (2) the evolutionary signal provided by indels is harnessed in the phylogenetic analysis, and (3) methods that utilize the phylogenetic signal in indels are developed for distance methods too. When the true homology is known and the amount of gaps is 20 percent of the alignment length or less, the methods used in this study are likely to yield trees with 90–100 percent accuracy.DNA sequences are used routinely to infer phylogenies [1-3]. The sequences within lineages (branches of the phylogenetic tree) evolve independently over time by means of several evolutionary processes, including point replacements of nucleotides (base subst
The impact of sequence parameter values on phylogenetic accuracy
Bhakti Dwivedi,Sudhindra R Gadagkar
Biology and Medicine , 2009,
Abstract: An accurately inferred phylogeny is important to the study of molecular evolution. Factors affecting the accuracy of aphylogenetic tree can be traced to several sequential steps leading to the inference of the phylogeny. I examine herethe features of the sequences in the alignment which impact phylogenetic (topological) accuracy rather than anysource of error during the process of sequence alignment or choice of the method of inference. Specifically, I studythe implications of the following five parameters, individually and in combination: sequence length, substitution rate,nucleotide base composition, the transition-transversion rate ratio and the rate heterogeneity among the sites. It isfound that the transition-transversion rate ratio or kappa has a significant impact on phylogenetic accuracy, with astrong positive interaction with accuracy at high substitution rates, contrary to general belief. This work on knownexpected tree has implications for the researcher in field and would enable them to choose from among the multiplegenes typically available today for an accurate phylogenetic inference. In addition, the increased accuracy withincrease in kappa suggest that the phylogenetic signal may be strong in the nucleotide sites that have experiencedconsiderable number of transversion than transition substitutions and thus can be useful in inference of a meaningfulphylogeny.
Lantana Camara Linn. (Raimuniya) : A Noxious Weed Having Pivotal Importance In Therapeutics
Dwivedi S,Dubey R,Patidar P,Dwivedi A
Pharmaceutical Reviews , 2008,
Abstract: Lantana camara Linn. is a significant weed of which there are some 650 varieties in over 60 countries or island groups.It is established and expanding in many regions of the world, often as a result of clearing of forest for timber or agriculture. It impacts severely on agriculture as well as on natural ecosystems. The plants can grow individually in clumps or as dense thickets, crowding out more desirable species. In disturbed native forests it can become the dominant understorey species, disrupting succession and decreasing biodiversity. Being the noxious nature of the weed, it is used in the treatment of various ailments. The present paper reviews the phytochemical profile and therapeutic efficacy of the plant.
Simulation Analysis on Applicability of Meta Material and PBG Based mm-Wave Planar Antenna for Advanced Cellular Technologies  [PDF]
Smrity Dwivedi
Open Journal of Antennas and Propagation (OJAPr) , 2017, DOI: 10.4236/ojapr.2017.51003
Abstract: Metamaterials have got a unique identification in the field of electromagnetic. Left handed metamaterials have been recognized through its working at high frequencies with larger bandwidth in antenna design. The author has proposed a multi substrates LH metamaterials with an array of split triangular antennas for wideband as well as for larger bandwidth. FR4 is being used at frequency 42 - 26 GHz with thickness of 3 mm for substrate and matching circuit is inserted to get high gain with minimum reflections. The number of rods in PBG is 100, which is found to get high return losses and ideal behavior of VSWR. Obtained results have been in good agreement such as S11 is approximately 30 dB, VSWR 1.8 dB and the bandwidth enhancement is 2 GHz at frequency 5 GHz. All results are plotted using commercial software CST microwave studio (Version 2012) and MATLAB.
Design of Wideband PBG Antenna for New Generation Communication Systems through Simulation  [PDF]
Smrity Dwivedi
Open Journal of Antennas and Propagation (OJAPr) , 2017, DOI: 10.4236/ojapr.2017.54013
In modern wireless communication system, demand of high bandwidth antennas with low cost are increased. In proposed paper, these requirements have been fully justified by using PBG based wideband antenna. Although, metamaterial is one more option to build this idea, sometimes, negative permittivity or negative permeability or both does not permit to allow easy fabrication and maintaining low cost. An antenna with several periodic rods and organic magnetic materials substrate made it possible to enhance the bandwidth and think off using it for 5G communication systems. Proposed antenna is designed and fabricated for frequency range of 40 GHz - 50 GHz, and 12 × 9 periodic rods with substrate having organic magnetic materials property. Antenna is designed and analyzed using commercial simulation software CST microwave studio (CST STUDIO SUITE 2014) and measured for return loss and VSWR for fabricated design. Obtained results meet the requirement of wider bandwidth of 1.5 - 2 GHz and return loss, ?35 dB, and directivity is 61 dBi with efficiency of 61%.
Clinical importance of quality of life measures in head and neck cancer
Kazi R,Sayed S,Dwivedi R
Indian Journal of Cancer , 2010,
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