Displaying publications 41 - 60 of 576 in total

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  1. Kumarasamy V, Kuppusamy UR, Samudi C, Kumar S
    Parasitol Res, 2013 Oct;112(10):3551-5.
    PMID: 23933809 DOI: 10.1007/s00436-013-3538-5
    Blastocystis sp. is a commonly found intestinal microorganism and was reported to cause many nonspecific gastrointestinal symptoms. Various subtypes have been previously reported, and the pathogenicity of different subtypes of Blastocystis is unclear and remains as a controversial issue. A recent study has shown that the Blastocystis antigen isolated from an unknown subtype could facilitate the proliferation of colon cancer cells. Current study was conducted to compare the effect of solubilized antigen isolated from five different subtypes of Blastocystis on colon cancer cells, HCT116. A statistically significant proliferation of these cells was observed when exposed to 1.0 μg/ml solubilized antigen isolated from subtype 3 Blastocystis (37.22%, p < 0.05). Real-time polymerase chain reaction demonstrated the upregulation of Th2 cytokines especially transforming growth factor beta in subtype 3-treated cancer cells (p < 0.01, 3.71-fold difference). Of interest, subtype 3 Blastocystis antigen also caused a significantly higher upregulation of cathepsin B (subtypes 1 and 2, p < 0.01; subtypes 4 and 5, p < 0.001; 6.71-fold difference) which lead to the postulation that it may enhance the exacerbation of existing colon cancer cells by weakening the cellular immune response. The dysregulation of IFN-γ and p53 expression also suggest Blastocystis as a proponent of carcinogenesis. Therefore, it is very likely for subtype 3 Blastocystis to have higher pathogenic potential as it caused an increased propagation of cancer cells and substantial amount of inflammatory reaction compared to other subtypes.
  2. Rajan DS, Rajkumar M, Srinivasan R, Harikumar RP, Suresh S, Kumar S
    Pak J Biol Sci, 2013 Nov 01;16(21):1336-41.
    PMID: 24511743
    Seaweeds have been used by mankind as medicine and food for more than 13,000 years. Marine algae are considered to produce a valuable phytoconstituents characterized by a broad spectrum of antitumor activities. The aim of the present study was to explore the effect of different solvent extracts of Sargassum wightii, Greville against Dalton's Ascitic Lymphoma (DAL) in Swiss male albino mice. DAL cells were injected intraperitoneally 1 x10(6) cell to the mice. Two days after cells injection the animals were treated with different solvent extracts of Sargassum wightii at dose of 200 mg kg(-1) for 14 days. 5-fluorouracil (20 mg kg(-1)) was used as reference drug. On day 11, cancer cell number, packed cell volume, decrease in tumour weight of the mice, increase in life span and hematological parameters were evaluated and compared with the same parameters in control. A significant increase in the life span and a decrease in the cancer cell number and tumour weight were noted in the tumour-induced mice after treatment with the extract. The haematological parameters were also normalized by the ethanolic and chloroform extracts in tumour-induced mice. These observations are suggestive of the protective effect of ethanolic extract of Sargassum wightii is comparatively better than other two tested extracts against Dalton's Ascitic Lymphoma (DAL).
  3. Anis SN, Iqbal NM, Kumar S, Al-Ashraf A
    Bioengineered, 2013 Mar-Apr;4(2):115-8.
    PMID: 23018620 DOI: 10.4161/bioe.22350
    A simple procedure for recovering biodegradable polymer from bacterial cells has been developed using economical and environmentally friendly solvent or chemicals. Recombinant bacterium, Cupriavidus necator harboring pBBR1MCS-C2 plasmid polyhydroxyalkanoate (PHA) synthase gene was used for the production of copolymer P(3HB-co-3HHx) from crude palm kernel oil (CPKO). NaOH was chosen in this study as it could give high purity and recovery yield. Increase of NaOH concentration had resulted in an increase of the PHA purity, but the recovery yield had decreased. The greater improvement of PHA purity and recovery were achieved by incubating the freeze-dried cells (10-30 g/L) in NaOH (0.1 M) for 1-3 h at 30°C and polishing using 20% (v/v) of ethanol. The treatment caused negligible degradation of the molecular weight of PHA recovered from the bacterial cells. The present review also highlights other extraction methods to provide greater insights into economical and sustainable recovery of PHA from bacterial cells.
  4. Chatrchyan S, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, et al.
    Phys Rev Lett, 2014 Apr 25;112(16):161802.
    PMID: 24815637
    Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top quark (the top squark) and the Higgs boson (Higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7  fb-1 of proton-proton collision data at s=8  TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the top squark mass below 360 to 410 GeV, depending on the Higgsino mass.
  5. Chen DC, Chen LY, Ling QD, Wu MH, Wang CT, Suresh Kumar S, et al.
    Biomaterials, 2014 May;35(14):4278-87.
    PMID: 24565521 DOI: 10.1016/j.biomaterials.2014.02.004
    The purification of human adipose-derived stem cells (hADSCs) from human adipose tissue cells (stromal vascular fraction) was investigated using membrane filtration through poly(lactide-co-glycolic acid)/silk screen hybrid membranes. Membrane filtration methods are attractive in regenerative medicine because they reduce the time required to purify hADSCs (i.e., less than 30 min) compared with conventional culture methods, which require 5-12 days. hADSCs expressing the mesenchymal stem cell markers CD44, CD73, and CD90 were concentrated in the permeation solution from the hybrid membranes. Expression of the surface markers CD44, CD73, and CD99 on the cells in the permeation solution from the hybrid membranes, which were obtained using 18 mL of feed solution containing 50 × 10⁴ cells, was statistically significantly higher than that of the primary adipose tissue cells, indicating that the hADSCs can be purified in the permeation solution by the membrane filtration method. Cells expressing the stem cell-associated marker CD34 could be successfully isolated in the permeation solution, whereas CD34⁺ cells could not be purified by the conventional culture method. The hADSCs in the permeation solution demonstrated a superior capacity for osteogenic differentiation based on their alkali phosphatase activity, their osterix gene expression, and the results of mineralization analysis by Alizarin Red S and von Kossa staining compared with the cells from the suspension of human adipose tissue. These results suggest that the hADSCs capable of osteogenic differentiation preferentially permeate through the hybrid membranes.
  6. Kumar S, Neven LG, Yee WL
    J Econ Entomol, 2014 Jun;107(3):1032-44.
    PMID: 25026662
    Sweet cherries, Prunus avium (L.) L., grown in the western United States are exported to many countries around the world. Some of these countries have enforced strict quarantine rules and trade restrictions owing to concerns about the potential establishment and subsequent spread of western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), a major quarantine pest of sweet cherry. We used 1) niche models (CLIMEX and MaxEnt) to map the climatic suitability, 2) North Carolina State University-Animal and Plant Health Inspection Service Plant Pest Forecasting System to examine chilling requirement, and 3) host distribution and availability to assess the potential for establishment of R. indifferens in areas of western North America where it currently does not exist and eight current or potential fresh sweet cherry markets: Colombia, India, Indonesia, Malaysia, Taiwan, Thailand, Venezuela, and Vietnam. Results from niche models conformed well to the current distribution of R. indifferens in western North America. MaxEnt and CLIMEX models had high performance and predicted climatic suitability in some of the countries (e.g., Andean range in Colombia and Venezuela, northern and northeastern India, central Taiwan, and parts of Vietnam). However, our results showed no potential for establishment of R. indifferens in Colombia, Indonesia, Malaysia, Taiwan, Thailand, Venezuela, and Vietnam when the optimal chilling requirement to break diapause (minimum temperature < or = 3 degree C for at least 15 wk) was used as the criterion for whether establishment can occur. Furthermore, these countries have no host plant species available for R. indifferens. Our results can be used to make scientifically informed international trade decisions and negotiations by policy makers.
  7. CMS Collaboration, Chatrchyan S, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, et al.
    Eur Phys J C Part Fields, 2014 08 07;74(8):2973.
    PMID: 25814904
    Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at [Formula: see text][Formula: see text] in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either [Formula: see text], [Formula: see text] or [Formula: see text], [Formula: see text], or [Formula: see text]). The results are based on data corresponding to an integrated luminosity of 18.9 fb[Formula: see text] collected with the CMS detector at the Large Hadron Collider. The measured cross sections, [Formula: see text] and [Formula: see text], are consistent with next-to-leading order quantum chromodynamics calculations.
  8. CMS Collaboration, Chatrchyan S, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, et al.
    Eur Phys J C Part Fields, 2014 08 20;74(8):3014.
    PMID: 25814909
    The normalised differential top quark-antiquark production cross section is measured as a function of the jet multiplicity in proton-proton collisions at a centre-of-mass energy of 7[Formula: see text] at the LHC with the CMS detector. The measurement is performed in both the dilepton and lepton+jets decay channels using data corresponding to an integrated luminosity of 5.0[Formula: see text]. Using a procedure to associate jets to decay products of the top quarks, the differential cross section of the [Formula: see text] production is determined as a function of the additional jet multiplicity in the lepton+jets channel. Furthermore, the fraction of events with no additional jets is measured in the dilepton channel, as a function of the threshold on the jet transverse momentum. The measurements are compared with predictions from perturbative quantum chromodynamics and no significant deviations are observed.
  9. CMS Collaboration, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, et al.
    Eur Phys J C Part Fields, 2014 09 17;74(9):3060.
    PMID: 25814914
    A measurement of the cross section for the production of top quark-antiquark pairs ([Formula: see text]) in association with a vector boson V (W or Z) in proton-proton collisions at [Formula: see text][Formula: see text] is presented. The results are based on a dataset corresponding to an integrated luminosity of 19.5 fb[Formula: see text] recorded with the CMS detector at the LHC. The measurement is performed in three leptonic (e and [Formula: see text]) channels: a same-sign dilepton analysis targeting [Formula: see text] events, and trilepton and four-lepton analyses designed for [Formula: see text] events. In the same-sign dilepton channel, the [Formula: see text] cross section is measured as [Formula: see text], corresponding to a significance of 1.6 standard deviations over the background-only hypothesis. Combining the trilepton and four-lepton channels, a direct measurement of the [Formula: see text] cross section, [Formula: see text], is obtained with a significance of 3.1 standard deviations. The measured cross sections are compatible with standard model predictions within their experimental uncertainties. The inclusive [Formula: see text] process is observed with a significance of 3.7 standard deviations from the combination of all three leptonic channels.
  10. CMS Collaboration, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, et al.
    Eur Phys J C Part Fields, 2014 09 26;74(9):3036.
    PMID: 25814912
    Searches for the direct electroweak production of supersymmetric charginos, neutralinos, and sleptons in a variety of signatures with leptons and [Formula: see text], [Formula: see text], and Higgs bosons are presented. Results are based on a sample of proton-proton collision data collected at center-of-mass energy [Formula: see text] with the CMS detector in 2012, corresponding to an integrated luminosity of 19.5 [Formula: see text]. The observed event rates are in agreement with expectations from the standard model. These results probe charginos and neutralinos with masses up to 720 [Formula: see text], and sleptons up to 260 [Formula: see text], depending on the model details.
  11. Adnan S, Ratnam S, Kumar S, Paterson D, Lipman J, Roberts J, et al.
    Anaesth Intensive Care, 2014 Nov;42(6):715-22.
    PMID: 25342403
    Augmented renal clearance (ARC) refers to increased solute elimination by the kidneys. ARC has considerable implications for altered drug concentrations. The aims of this study were to describe the prevalence of ARC in a select cohort of patients admitted to a Malaysian intensive care unit (ICU) and to compare measured and calculated creatinine clearances in this group. Patients with an expected ICU stay of <24 hours plus an admission serum creatinine concentration <120 µmol/l, were enrolled from May to July 2013. Twenty-four hour urinary collections and serum creatinine concentrations were used to measure creatinine clearance. A total of 49 patients were included, with a median age of 34 years. Most study participants were male and admitted after trauma. Thirty-nine percent were found to have ARC. These patients were more commonly admitted in emergency (P=0.03), although no other covariants were identified as predicting ARC, likely due to the inclusion criteria and the study being under-powered. Significant imprecision was demonstrated when comparing calculated Cockcroft-Gault creatinine clearance (Crcl) and measured Crcl. Bias was larger in ARC patients, with Cockcroft-Gault Crcl being significantly lower than measured Crcl (P <0.01) and demonstrating poor correlation (rs=-0.04). In conclusion, critically ill patients with 'normal' serum creatinine concentrations have varied Crcl. Many are at risk of ARC, which may necessitate individualised drug dosing. Furthermore, significant bias and imprecision between calculated and measured Crcl exists, suggesting clinicians should carefully consider which method they employ in assessing renal function.
  12. CMS Collaboration, Chatrchyan S, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, et al.
    Eur Phys J C Part Fields, 2014 11 12;74(11):3129.
    PMID: 25814874
    A measurement of differential cross sections for the production of a pair of isolated photons in proton-proton collisions at [Formula: see text] is presented. The data sample corresponds to an integrated luminosity of 5.0[Formula: see text] collected with the CMS detector. A data-driven isolation template method is used to extract the prompt diphoton yield. The measured cross section for two isolated photons, with transverse energy above 40 and 25[Formula: see text] respectively, in the pseudorapidity range [Formula: see text], [Formula: see text] and with an angular separation [Formula: see text], is [Formula: see text][Formula: see text]. Differential cross sections are measured as a function of the diphoton invariant mass, the diphoton transverse momentum, the azimuthal angle difference between the two photons, and the cosine of the polar angle in the Collins-Soper reference frame of the diphoton system. The results are compared to theoretical predictions at leading, next-to-leading, and next-to-next-to-leading order in quantum chromodynamics.
  13. Rajiah K, Veettil SK, Kumar S
    Clin Teach, 2014 Dec;11(7):551-6.
    PMID: 25417986 DOI: 10.1111/tct.12213
    The evaluation of clinical skills and competencies is a high-stakes process carrying significant consequences for the candidate. Hence, it is mandatory to have a robust method to justify the pass score in order to maintain a valid and reliable objective structured clinical examination (OSCE). The aim was to trial the borderline approach using the two-domain global rating scale for standard setting in the OSCE.
  14. Kumar SS, Alarfaj AA, Munusamy MA, Singh AJ, Peng IC, Priya SP, et al.
    Int J Mol Sci, 2014;15(12):23418-47.
    PMID: 25526563 DOI: 10.3390/ijms151223418
    Human pluripotent stem cells, including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), hold promise as novel therapeutic tools for diabetes treatment because of their self-renewal capacity and ability to differentiate into beta (β)-cells. Small and large molecules play important roles in each stage of β-cell differentiation from both hESCs and hiPSCs. The small and large molecules that are described in this review have significantly advanced efforts to cure diabetic disease. Lately, effective protocols have been implemented to induce hESCs and human mesenchymal stem cells (hMSCs) to differentiate into functional β-cells. Several small molecules, proteins, and growth factors promote pancreatic differentiation from hESCs and hMSCs. These small molecules (e.g., cyclopamine, wortmannin, retinoic acid, and sodium butyrate) and large molecules (e.g. activin A, betacellulin, bone morphogentic protein (BMP4), epidermal growth factor (EGF), fibroblast growth factor (FGF), keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), noggin, transforming growth factor (TGF-α), and WNT3A) are thought to contribute from the initial stages of definitive endoderm formation to the final stages of maturation of functional endocrine cells. We discuss the importance of such small and large molecules in uniquely optimized protocols of β-cell differentiation from stem cells. A global understanding of various small and large molecules and their functions will help to establish an efficient protocol for β-cell differentiation.
  15. Kaiwartya O, Kumar S, Lobiyal DK, Abdullah AH, Hassan AN
    Sensors (Basel), 2014;14(12):22342-71.
    PMID: 25429415 DOI: 10.3390/s141222342
    Geographic routing is one of the most investigated themes by researchers for reliable and efficient dissemination of information in Vehicular Ad Hoc Networks (VANETs). Recently, different Geographic Distance Routing (GEDIR) protocols have been suggested in the literature. These protocols focus on reducing the forwarding region towards destination to select the Next Hop Vehicles (NHV). Most of these protocols suffer from the problem of elevated one-hop link disconnection, high end-to-end delay and low throughput even at normal vehicle speed in high vehicle density environment. This paper proposes a Geographic Distance Routing protocol based on Segment vehicle, Link quality and Degree of connectivity (SLD-GEDIR). The protocol selects a reliable NHV using the criteria segment vehicles, one-hop link quality and degree of connectivity. The proposed protocol has been simulated in NS-2 and its performance has been compared with the state-of-the-art protocols: P-GEDIR, J-GEDIR and V-GEDIR. The empirical results clearly reveal that SLD-GEDIR has lower link disconnection and end-to-end delay, and higher throughput as compared to the state-of-the-art protocols. It should be noted that the performance of the proposed protocol is preserved irrespective of vehicle density and speed.
  16. Safi SZ, Qvist R, Kumar S, Batumalaie K, Ismail IS
    Biomed Res Int, 2014;2014:801269.
    PMID: 25105142 DOI: 10.1155/2014/801269
    The growing number of people with diabetes worldwide suggests that diabetic retinopathy (DR) and diabetic macular edema (DME) will continue to be sight threatening factors. The pathogenesis of diabetic retinopathy is a widespread cause of visual impairment in the world and a range of hyperglycemia-linked pathways have been implicated in the initiation and progression of this condition. Despite understanding the polyol pathway flux, activation of protein kinase C (KPC) isoforms, increased hexosamine pathway flux, and increased advanced glycation end-product (AGE) formation, pathogenic mechanisms underlying diabetes induced vision loss are not fully understood. The purpose of this paper is to review molecular mechanisms that regulate cell survival and apoptosis of retinal cells and discuss new and exciting therapeutic targets with comparison to the old and inefficient preventive strategies. This review highlights the recent advancements in understanding hyperglycemia-induced biochemical and molecular alterations, systemic metabolic factors, and aberrant activation of signaling cascades that ultimately lead to activation of a number of transcription factors causing functional and structural damage to retinal cells. It also reviews the established interventions and emerging molecular targets to avert diabetic retinopathy and its associated risk factors.
  17. Rashid MH, Hossain MA, Kashem MA, Kumar S, Rafii MY, Latif MA
    ScientificWorldJournal, 2014;2014:639246.
    PMID: 24723819 DOI: 10.1155/2014/639246
    Botrytis gray mold (BGM) caused by Botrytis cinerea Pers. Ex. Fr. is an extremely devastating disease of chickpea (Cicer arietinum L.) and has a regional as well as an international perspective. Unfortunately, nonchemical methods for its control are weak and ineffective. In order to identify an effective control measure, six fungicides with different modes of action were evaluated on a BGM susceptible chickpea variety BARIchhola-1 at a high BGM incidence location (Madaripur) in Bangladesh for three years (2008, 2009, and 2010). Among the six fungicides tested, one was protectant [Vondozeb 42SC, a.i. mancozeb (0.2%)], two systemic [Bavistin 50 WP, a.i. carbendazim (0.2%), and Protaf 250EC, propiconazole (0.05%)], and three combination formulations [Acrobat MZ690, dimethomorph 9% + mancozeb 60%, (0.2%); Secure 600 WG, phenomadone + mancozeb (0.2%); and Companion, mancozeb 63% + carbendazim 12% (0.2%)]. The results showed superiority of combination formulations involving both protectant and systemic fungicides over the sole application of either fungicide separately. Among the combination fungicides, Companion was most effective, resulting in the lowest disease severity (3.33 score on 1-9 scale) and the highest increase (38%) of grain yield in chickpea. Therefore, this product could be preferred over the sole application of either solo protectant or systemic fungicides to reduce yield losses and avoid fungicide resistance.
  18. Chatrchyan S, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, et al.
    Eur Phys J C Part Fields, 2014;74(8):2980.
    PMID: 25814906
    A search for invisible decays of Higgs bosons is performed using the vector boson fusion and associated ZH production modes. In the ZH mode, the Z boson is required to decay to a pair of charged leptons or a [Formula: see text] quark pair. The searches use the 8 [Formula: see text] pp collision dataset collected by the CMS detector at the LHC, corresponding to an integrated luminosity of up to 19.7 [Formula: see text]. Certain channels include data from 7 [Formula: see text] collisions corresponding to an integrated luminosity of 4.9 [Formula: see text]. The searches are sensitive to non-standard-model invisible decays of the recently observed Higgs boson, as well as additional Higgs bosons with similar production modes and large invisible branching fractions. In all channels, the observed data are consistent with the expected standard model backgrounds. Limits are set on the production cross section times invisible branching fraction, as a function of the Higgs boson mass, for the vector boson fusion and ZH production modes. By combining all channels, and assuming standard model Higgs boson cross sections and acceptances, the observed (expected) upper limit on the invisible branching fraction at [Formula: see text] [Formula: see text] is found to be 0.58 (0.44) at 95 % confidence level. We interpret this limit in terms of a Higgs-portal model of dark matter interactions.
  19. Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, Dragicevic M, et al.
    Eur Phys J C Part Fields, 2014;74(10):3076.
    PMID: 25814871
    Observation of the diphoton decay mode of the recently discovered Higgs boson and measurement of some of its properties are reported. The analysis uses the entire dataset collected by the CMS experiment in proton-proton collisions during the 2011 and 2012 LHC running periods. The data samples correspond to integrated luminosities of 5.1[Formula: see text]at [Formula: see text] and 19.7[Formula: see text]at 8[Formula: see text] . A clear signal is observed in the diphoton channel at a mass close to 125[Formula: see text] with a local significance of [Formula: see text], where a significance of [Formula: see text] is expected for the standard model Higgs boson. The mass is measured to be [Formula: see text] , and the best-fit signal strength relative to the standard model prediction is [Formula: see text][Formula: see text][Formula: see text]. Additional measurements include the signal strength modifiers associated with different production mechanisms, and hypothesis tests between spin-0 and spin-2 models.
  20. CMS Collaboration, Khachatryan V, Sirunyan AM, Tumasyan A, Adam W, Bergauer T, et al.
    Eur Phys J C Part Fields, 2014;74(11):3149.
    PMID: 25814876 DOI: 10.1140/epjc/s10052-014-3149-z
    A search for heavy, right-handed neutrinos, [Formula: see text] ([Formula: see text]), and right-handed [Formula: see text] bosons, which arise in the left-right symmetric extensions of the standard model, has been performed by the CMS experiment. The search was based on a sample of two lepton plus two jet events collected in proton-proton collisions at a center-of-mass energy of 8[Formula: see text] corresponding to an integrated luminosity of 19.7 [Formula: see text]. For models with strict left-right symmetry, and assuming only one [Formula: see text] flavor contributes significantly to the [Formula: see text] decay width, the region in the two-dimensional [Formula: see text] mass plane excluded at a 95 % confidence level extends to approximately [Formula: see text] and covers a large range of neutrino masses below the [Formula: see text] boson mass, depending on the value of [Formula: see text]. This search significantly extends the [Formula: see text] exclusion region beyond previous results.
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