Praveen kumar S - Academia.edu (original) (raw)

Papers by Praveen kumar S

Asian Paleoanthropology

The timing of hominin dispersals during the early Pleistocene, specifically into East Asia, is we... more The timing of hominin dispersals during the early Pleistocene, specifically into East Asia, is well established. The pattern of migration across inner Asia and the subsequent duration/intensity of hominin colonization of these areas, however, are still poorly resolved. The large territory of Central Asia defines a clear path within Eurasia through which hominin dispersals farther east may have occurred. The purpose of the present study is to examine the degree to which an autochthonous evolutionary trajectory is supported in Central Asia and how the potential connections between this and neighboring regions may be characterized during the Pleistocene. Archaeological and human paleontological evidence from the region is reviewed and compared to that from the Near East, the Altai, and China. This review informs a more detailed analysis of the Central Asian Middle Paleolithic record. Prevailing theoretical models suggest that Central Asia was inhabited by Neandertals migrating from the west to seek refuge from expanding modern human populations during the Middle Paleolithic. Morphological analyses of the newly discovered Obi-Rakhmat hominin and a re-evaluation of the Teshik-Tash child, both from sites in Uzbekistan, provide a test of this model. Results indicate that evidence of the morphological pattern that typically describes European Neandertals is equivocal in Central Asia. Although both Obi-Rakhmat and Teshik-Tash express some Neandertal features, their morphologies also suggest some admixture with local populations and/or those migrating into Central Asia from the North and East.

LAP LAMBERT Academic Publishing eBooks, May 14, 2012

Today‘s world is very much polluted and very much risky for the living beings. There are many fac... more Today‘s world is very much polluted and very much risky for the living beings. There are many factors which are inhibiting our growth and increasing various diseases in human population and in other animals also. So I have summarized these factors in this book. This book has mainly focused on effects of mobile phone radiation on living beings. It dealt with various pathways in a cell undergoing changed due to radiations. I have tried to update as much information as I could in all the chapters. I have searched many articles and research work done till now to collect the latest information for the readers. I shall greatly appreciate interaction with the readers and shall welcome any suggestions/criticisms from the students as these would surely help me to improve the work. This book also contains a project study which demonstrates that how radiation can affect cell physiology and can produce tumors. It is expected that this book will surely provide a idea about the relation of radiation and their harmful effects. Thus it will make the people aware about their health. This is the main purpose of this book. I shall in any case welcome any suggestions/criticism for further improvement, since there surely remains a limitless scope for the same.

The effectiveness of a data retrieving method depends upon the data specific queries for retrievi... more The effectiveness of a data retrieving method depends upon the data specific queries for retrieving the data from the database. Fundamentally, iceberg queries are unique class of aggregation queries that compute aggregate values upon user interested threshold. The basic bitmap index technique is used to process an iceberg query by conducting a bitwise-AND operation between every pair of bitmap vectors that consumes a large amount of execution time to answer an iceberg query. Furthermore, this execution time increases when the cardinality of an attributes are increases. The major part taken into the consideration about the bitwise-AND operations in the iceberg queries. The reduced number of AND operation increases the effectiveness of the iceberg query. In this work, an efficient iceberg query evaluation process is proposed by removing the unnecessary fruitless bitwise-AND operations needed to find the item pairs. The proposed scheme is index-based technique. In this scheme, the inde...

The fiber optic system plays a major role in modern electronic communication system. The principl... more The fiber optic system plays a major role in modern electronic communication system. The principle of fiber optics is also used in many modern medical electronic fields like endoscopy devices. The optical property variation paves the way for selecting the fascinating project titled “Blood group detection using fiber optics” in determining the various blood groups of a human body. The analog input actuates a LED. The light pulses from the LED are allowed to fall on blood samples by using optical fiber cables. The other end of the optical cable is coupled to a pin-photo diode, which acts as a photo detector. Due to the optical variations of different blood groups there will be corresponding voltage variations in the output of the photo detector. Thereby we can identify the blood group easily.

MOJ Proteomics & Bioinformatics, May 30, 2017

Malaria is a vector-borne infectious disease caused by protozoan parasites of the genus Plasmodiu... more Malaria is a vector-borne infectious disease caused by protozoan parasites of the genus Plasmodium. Four types of the plasmodium parasite can infect humans; the most serious forms of the diseases are caused by Plasmodium falciparum. Plasmepsin group of enzymes are key enzymes in the life cycle of malarial parasites. Plasmepsin II enzyme is responsible for the formation of the hemozoin through the hemoglobin degradation pathway. Specification of potential drug target by inhibiting Plasmepsin II Enzyme, N-(R-Carboxy-Ethyl)-Alpha-(S)-(2-Phenylethyl) presently used as an inhibitor, to prevent the degradation. Changeover of side chains based on isomeric property of Achiral compounds is aimed to be a new inhibitor for the Plasmepsin II enzyme. Scaffold hopping is an approach used to discover new chemical classes by replacing a portion (the scaffold) of a known compound, while preserving the remaining chemical groups, under the assumption that they are important for biological activity. The main goal of this investigation was to find out the types of combination with the ligand to be the most active in the inhibition of Plasmepsin II enzyme, among the Achiral compounds. Achiral inhibitors revealed exploitation of a new inhibitor observed in Plasmepsin II protein, by Electrostatic potential, binding energy, and bond interactions.

International Journal of Microwave and Wireless Technologies, 2020

In this work, the authors report the operation of a cylindrical dielectric resonator antenna (CDR... more In this work, the authors report the operation of a cylindrical dielectric resonator antenna (CDRA) in the high gain HEM13 δ mode, for the first time. This mode, excited with a standard microstrip slot, radiates in the broadside direction with gain in the range of 8−10 dBi. It is shown that through feed optimization, the HEM13 δ mode can be excited dominantly by suppressing the fundamental HEM11 δ mode of the CDRA. Detailed simulation studies show that the HEM13 δ mode is supported by cylindrical dielectric resonators with an aspect ratio (radius to height ratio or a/d) >1, and it resonates at a frequency approximately 2.2 times that of the fundamental HEM11 δ mode. The above features of the HEM13 δ mode CDRA can be used as approximate design rules. For a CDRA with dielectric constant ɛr = 24, diameter 2a = 19.43 mm, and height d = 7.3 mm (a/d = 1.3), the HEM13 δ mode is excited at 6.125 GHz with a peak gain of 10.14 dBi in simulation. Corresponding values from prototype measurem...

IOP Conference Series: Materials Science and Engineering, 2018

Excitation of the higher order modes (HOM) of a cylindrical dielectric resonator antenna(DRA) of ... more Excitation of the higher order modes (HOM) of a cylindrical dielectric resonator antenna(DRA) of high relative permittivity, using dual feed scheme is investigated. The feed scheme uses a pair of narrow slots and is chosen on the basis of the field distribution of the desired DRA modes. Numerical studies using ANSYS HFSS show that the dual-feed excited a combination of two HOMs, which are identified as HEM 21 and TM 01. The mixed-up nature is further verified through studying the radiation pattern of the DRA which shows azimuthal asymmetry and low gain. It is suggested that if one of the HOM is suppressed, better antenna performance can be achieved.

Quaternary Science Reviews, 2019

South Asia has a rich Palaeolithic heritage, and chronological resolution for this record has sub... more South Asia has a rich Palaeolithic heritage, and chronological resolution for this record has substantially improved over the past decade as a result of focused, interdisciplinary research at a number of key sites. Expanding the spatial diversity of dated Palaeolithic sites in South Asia grows increasingly important to examine how patterns of change through time vary within and between the region's diverse habitats. Critically, alternate models of modern human dispersals into South Asia highlight the significance of either coastal or continental routes of dispersal, but currently no coastal Palaeolithic sites directly dating to the timeframe of human expansions are known. Our previous research in Kachchh was the first study to clearly identify the presence of Palaeolithic sites in Late Pleistocene landscapes in close proximity to the Indian Ocean coastline. Here, we present the first results of surface survey and test excavation at the site of Sandhav (Kachchh, India), approximately 25km from the modern shoreline. We characterise the geomorphology of the landscape, highlighting multiple phases of alluvial aggradation and post-depositional carbonate formation, associated with Palaeolithic artefacts. To date, excavations have tested the uppermost Pleistocene deposit, yielding a small collection of fresh Middle Palaeolithic artefacts associated with a luminescence age dating to the first half of MIS 5 (~114 ka), which provides a minimum age for Late Acheulean artefacts in underlying units. We discuss our findings in the context of debates surrounding the timing, lithic technologies, and ecologies associated with the expansions of modern humans into South Asia.

Microwave and Optical Technology Letters, 2019

In this article, excitation of the magnetic quadrupole mode of a cylindrical dielectric resonator... more In this article, excitation of the magnetic quadrupole mode of a cylindrical dielectric resonator antenna, designated as the HEM 21δ mode, using planar feeding technique is discussed for the first time. Two types of planar feeds-a dualmicrostrip feed and a dual-slot feed are numerically investigated. Results show that the dual-slot feed is more suitable for exciting the HEM 21δ mode as it gives better symmetry of the radiation pattern and lower cross-polarization level. A DRA prototype (dielectric constant, ε r = 24, loss tangent, tanδ = 0.002, diameter, 2a = 19.43 mm and height, h = 7.3 mm) using dual-slot feed is fabricated and characterized. Measurements demonstrate a resonant frequency of~4.96 GHz, bandwidth of~4.4%, peak gain of~3.45 dBi and peak cross-polar level of~− 11 dB for the HEM 21δ mode, which are in decent agreement with numerical predictions.

IETE Journal of Research, 2019

This paper presents the numerical and experimental investigations on the use of a cylindrical die... more This paper presents the numerical and experimental investigations on the use of a cylindrical dielectric resonator (DR) as a displacement sensor in the millimetre range, for the first time. The sensor principle is based on the sensitivity of the coupling between a resonator and a transmission line, which is a simple microstrip line in the present context, to positional changes (displacement) of the resonator. Corresponding change in the input reflection coefficient of the microstrip line can be used to quantify the displacement. It is demonstrated numerically that the sensitivity and the linearity of the displacement sensing are highly dependent on the dielectric constant of the DR, a feature that is absent in other resonator-based sensors. Experimental results for an available DR sample of dielectric constant 24, diameter 19.43 mm and height 7.3 mm, operating in the HEM 11δ mode with a resonant frequency of 3.41 GHz are presented to validate the simulations. Analysis of the results shows that in the measurement range of 1-8 mm, the above arrangement gives a sensitivity of 2.01 dB/mm. Such displacement sensors may find application in strain or pressure measurement, as well as in diagnosing alignment or positional errors.

Journal of maxillofacial and oral surgery, 2018

BMJ open ophthalmology, 2017

To identify the effects of chronic alcohol and/or tobacco use on retinal nerve fibre layer (RNFL)... more To identify the effects of chronic alcohol and/or tobacco use on retinal nerve fibre layer (RNFL) thickness and to find the association between severity of addiction with RNFL thinning. A case-control study was performed in 200 eyes of cases and 200 healthy control eyes. Cases were recruited from deaddiction clinic having history of alcohol and/or tobacco use for at least 5 years. Severity of alcohol and tobacco was graded by Alcohol Use Disorders Identification Test (AUDIT) and Fagerstorm Nicotine Dependence (FTND) scale, respectively. Age-matched and gender-matched individuals attending ophthalmology outpatient department without addiction were recruited as controls. RNFL thickness was measured using Stratus optical coherence tomography (OCT). Statistically significant RNFL thinning was noted in all quadrants except nasal quadrant in the cases. Statistically significant thinning was seen in all quadrants except nasal with increased FTND scale. Thinning was noted in all quadrants w...

for their useful questions and comments. The views expressed herein are those of the authors and ... more for their useful questions and comments. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. At least one co-author has disclosed a financial relationship of potential relevance for this research. Further information is available online at http://www.nber.org/papers/w23829.ack NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

Annual review of biochemistry, Jan 2, 2016

Ice-binding proteins (IBPs) are a diverse class of proteins that assist organism survival in the ... more Ice-binding proteins (IBPs) are a diverse class of proteins that assist organism survival in the presence of ice in cold climates. They have different origins in many organisms, including bacteria, fungi, algae, diatoms, plants, insects, and fish. This review covers the gamut of IBP structures and functions and the common features they use to bind ice. We discuss mechanisms by which IBPs adsorb to ice and interfere with its growth, evidence for their irreversible association with ice, and methods for enhancing the activity of IBPs. The applications of IBPs in the food industry, in cryopreservation, and in other technologies are vast, and we chart out some possibilities.

Sn-Ag-Cu (SAC) solders are susceptible to appreciable microstructural coarsening due to the combi... more Sn-Ag-Cu (SAC) solders are susceptible to appreciable microstructural coarsening due to the combined effect of thermal and mechanical stimuli during service and storage. This results in evolution of joint properties over time, and thereby influences the long-term reliability of microelectronic packages. Accurate prediction of this aging behavior is therefore critical for joint reliability predictions. Here, we study the coarsening behavior of ball grid array (BGA) joints of Sn-3.8Ag-0.7Cu (SAC387) solder attached to ENIG bond-pads with four different thermo-mechanical histories. Both Ag3Sn and Cu6Sn5 precipitates underwent rapid coarsening due to the combined effects of the temperature and superimposed inelastic strain. However, following aging, the Cu6Sn5 particles were much coarser than the Ag3Sn precipitates, and numbered about ~100 times less. Therefore the mechanical behavior evolution during aging is dominated by the coarsening kinetics of Ag3Sn. Based on these observations, a...

Scientific Reports, 2015

The fundamental task in RNA-Seq-based transcriptome analysis is alignment of millions of short re... more The fundamental task in RNA-Seq-based transcriptome analysis is alignment of millions of short reads to the reference genome or transcriptome. Choosing the right tool for the dataset in hand from many existent RNA-Seq alignment packages remains a critical challenge for downstream analysis. To facilitate this choice, we designed a novel tool for comparing alignment results of user data based on the relative reliability of uniquely aligned reads (CADBURE). CADBURE can easily evaluate different aligners, or different parameter sets using the same aligner, and selects the best alignment result for any RNA-Seq dataset. Strengths of CADBURE include the ability to compare alignment results without the need for synthetic data such as simulated genomes, alignment regeneration and randomly subsampled datasets. The benefit of a CADBURE selected alignment result was supported by differentially expressed gene (DEG) analysis. We demonstrated that the use of CADBURE to select the best alignment from a number of different alignment results could change the number of DEGs by as much as 10%. In particular, the CADBURE selected alignment result favors fewer false positives in the DEG analysis. We also verified differential expression of eighteen genes with RT-qPCR validation experiments. CADBURE is an open source tool (http://cadbure.sourceforge.net/). RNA-Seq analysis describes the collection of methods to characterize transcriptomes using high-throughput sequencing of abundant cDNA fragments 1,2. The fundamental task in RNA-Seq-based transcriptome analysis is spliced alignment (called aligning or mapping) of short sequencing reads to the reference genome or transcriptome 1-3. The complexities inherent in RNA-seq data require specialized tools (i.e., aligner) to map them to genome. RNA-seq data possesses many complexities like alternate splice isoforms that can contain many different combinations of exons transcribed from a gene 2,4. As with many high-throughput sequencing technologies, the sequence fragments are short (35 nt to 100 nt), presenting considerable challenges to an aligner which must determine the unique mapping location among the many possible locations in the reference genome 5,6. Furthermore, the reference genome is most often different than that of the actual biological source of RNAs being sequenced. Organism-specific sequence properties like repetitive sequences, gene structures, polymorphisms, and RNA polymerase fidelity compound the difficulty in achieving proper alignment of a given sequence read. In these circumstances, the aligner's solution is often a compromise between the sensitivity and specificity provided an initial level of heuristic match 2,7-11. This tradeoff in specificity and sensitivity makes an aligner work better on some datasets than others. In RNA-Seq projects, one major challenge is to choose a right mapping tool among many existing tools. Current tools available for mapping sequencing reads include GSNAP 9 , TopHat2 8 , CLC Genomics Workbench (CLC Bio-Qiagen, Aarhus, Denmark), MapSplice 11 , PALMapper 12 , STAR 13 to name a few (for an exhaustive list see 14). Although many previous investigations compared different aligners 3,8,9,11,13,15 , to

ChemInform, 2007

Enantiospecific syntheses of derivatives all the four diastereomers of A-ring enyne synthon of 1α... more Enantiospecific syntheses of derivatives all the four diastereomers of A-ring enyne synthon of 1α,25-dihydroxyvitamin D 3 (5-ethynyl-4-methylcyclohex-4-en-1,3-diol) have been described starting from the abundantly available monoterpene (R)-carvone, exploiting the isopropenyl group of carvone as an equivalent of an hydroxy group. A combination of Criegee rearrangement and Mitsunobu reactions has been strategically employed.

Multinational Finance Journal, 2008

The quality of corporate governance has been shown to have wide-ranging implications, e.g., on th... more The quality of corporate governance has been shown to have wide-ranging implications, e.g., on the performance of stock markets and on exchange rates. This study investigates whether the quality of corporate governance in a country impacts investment decisions made at the micro level of the firm. The study focuses on Asian emerging markets since they have widely varying standards of corporate governance. Based on eight measures of corporate governance, four aggregate indices of corporate governance (business environment, legal environment, investor rights, and an overall measure) are developed for seven countries in the sample drawing on data from published sources. The results indicate that improvements in corporate governance mitigate the dependency of firm investments on their internal resources and facilitate access by firms to capital markets (JEL: G15, G30, G31).

$Research paper thumbnail of Effects of strain rate and aging on deformation and fracture of Sn-Ag-Cu solder joints$

2008 11th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, 2008

Abstract With the proliferation of mobile electronics in everyday life, the ability of electronic... more Abstract With the proliferation of mobile electronics in everyday life, the ability of electronic packages to sustain impact loading under drop conditions has become a paramount reliability concern. Since solder joints, which serve as mechanical and electrical ...

Journal of Nepal Chemical Society, 2013

In the course of screening of plant extracts for antimicrobial activity, the methanolic extract o... more In the course of screening of plant extracts for antimicrobial activity, the methanolic extract of Bergenia ligulata (Saxifragaceae) exhibited antibacterial activity against gram-positive bacteria. Fractionation of ethylacetate soluble phase of the methanol extract led to the isolation of bergenin (1), 11-O-p-hydroxybenzoylbergenin (2), 6-O-galloylarbutin (3) and epiafzelechin (4). Except bergenin, other compounds were isolated for the first time from B. ligulata. DOI: http://dx.doi.org/10.3126/jncs.v28i0.8118 Journal of Nepal Chemical Society Vol. 28, 2011 Page: 110-114 Uploaded Date: May 24, 2013