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Search Results: 1 - 10 of 1815 matches for " Rana Chattopadhyay "
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Plasmodium yoelii-Infected A. stephensi Inefficiently Transmit Malaria Compared to Intravenous Route
Solomon Conteh,Rana Chattopadhyay,Charles Anderson,Stephen L. Hoffman
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0008947
Abstract: It was recently reported that when mosquitoes infected with P. berghei sporozoites feed on mice, they deposit approximately 100–300 sporozoites in the dermis. When we inoculate P. yoelii (Py) sporozoites intravenously (IV) into BALB/c mice, the 50% infectious dose (ID50) is often less than 3 sporozoites, indicating that essentially all Py sporozoites in salivary glands are infectious. Thus, it should only take the bite of one infected mosquito to infect 100% of mice. In human subjects, it takes the bite of at least 5 P. falciparum-infected mosquitoes to achieve 100% blood stage infection. Exposure to 1–2 infected mosquitoes only leads to blood stage infection in approximately 50% of subjects. If mosquitoes carrying Py sporozoites inoculate 100–300 sporozoites per bite, and 1 to 2 mosquito bites achieve 50% blood stage infection rates, then this would suggest that the majority of sporozoites inoculated by mosquitoes into the dermis are not responsible for a productive infection, or that a significant number of sporozoite-infected mosquitoes do not inoculate any sporozoites. The objective of this study was to determine if this is the case. We therefore studied the infectivity to mice of the bites of 1, 2, 4, or 5–8 Py-infected mosquitoes. The bite of one Py sporozoite-infected mosquito caused blood stage infection in 41.4% (12/29) of mice, two bites infected 66.7% (22/33), four bites infected 75% (18/24), and five to eight bites infected 100% (21/21). These findings demonstrate that inoculation of sporozoites by mosquito bite is much less efficient than IV inoculation of Py sporozoites by needle and syringe. Such data may have implications for determining the best route and dose of administration to humans of our attenuated P. falciparum sporozoite vaccine, the scientific basis of which is immunity by bites from irradiated infected mosquitoes, and suggest that the challenge is to develop a method of administration that approximates IV inoculation, not one that mimics mosquito bite.
Analytical Solution for Bending Stress Intensity Factor from Reissner’S Plate Theory  [PDF]
Lalitha Chattopadhyay
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.35060
Abstract: Plate-type structural members are commonly used in engineering applications like aircraft, ships nuclear reactors etc. These structural members often have cracks arising from manufacture or from material defects or stress concentrations. Designing a structure against fracture in service involves consideration of strength of the structure as a function of crack size, dimension and the applied load based on principles of fracture mechanics. In most of the engineering structures the plate thickness is generally small and in these cases though the classical plate theory has provided solutions, the neglect of transverse shear deformation leads to the limitation that only two conditions can be satisfied on any boundary whereas we have three physical boundary conditions on an edge of a plate. In this paper this incompatibility is eliminated by using Reissner plate theory where the transverse shear deformation is included and three physically natural boundary conditions of vanishing bending moment, twisting moment and transverse shear stress are satisfied at a free boundary. The problem of estimating the bending stress distribution in the neighbourhood of a crack located on a single line in an elastic plate of varying thickness subjected to out-of-plane moment applied along the edges of the plate is examined. Using Reissner’s plate theory and integral transform technique, the general formulae for the bending moment and twisting moment in an elastic plate containing cracks located on a single line are derived. The thickness depended solution is obtained in a closed form for the case in which there is a single crack in an infinite plate and the results are compared with those obtained from the literature.
Slow Structural Change in India: Is It Related to Rising Relative Price of Agriculture? A Partial Equilibrium Model  [PDF]
Subhasankar Chattopadhyay
Theoretical Economics Letters (TEL) , 2016, DOI: 10.4236/tel.2016.63044
Abstract: Economic growth across countries is associated with changes in the composition of sectoral output, employment and consumption structure, known as “structural change”. With high growth rates in the Indian economy in the post liberalization period, structural change is expected to be rapid. However, the share of the manufacturing sector has “crossed” over that of the agriculture only very recently from the supply side and yet to cross over from the demand side. Through a simple partial equilibrium model, this paper shows that such slow structural change may be linked to a secular rise in the relative price of agricultural goods in India.
Policy Initiative for Balance Regional Development and Growth  [PDF]
Rajeev Rana
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.814188
Abstract: The economics growth and development mostly coined together, and it was thought that growth itself led to development of the country but it was found that there are more dissimilarities than complementary. A higher growth will spontaneously lead development only when there is equitable distribution of resources and balancing regional development. But it did not happen in practices as high growth widen inequality and unequal distribution between the different groups of people in the societies as well between inter-state and intra-state to create regional imbalance, further as there is a transition period of the economy and urbanization took place it was experienced that regional imbalance widen in the term of class difference, gender discrimination (lower participation of women, as well alarming sex ratio), resources distribution, and per capital income. Further, the regional economic disparities create more inequality between savings, investment, and had interconnected map over the vicious cycle of corruption, demographic challenges, influencing chronic & infectious diseases, illicit trade, migration, food insecurity, and governance failures. The paper is addressing those various issues and thrust area of policy initiatives to present the causes of regional imbalance and growth as well the policy initiative for inclusive development.
Establishment of an In Vitro Assay for Assessing the Effects of Drugs on the Liver Stages of Plasmodium vivax Malaria
Rana Chattopadhyay,Soundarapandian Velmurugan,Chinnamma Chakiath,Lucy Andrews Donkor,Wilbur Milhous,John W. Barnwell,William E. Collins,Stephen L. Hoffman
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0014275
Abstract: Plasmodium vivax (Pv) is the second most important human malaria parasite. Recent data indicate that the impact of Pv malaria on the health and economies of the developing world has been dramatically underestimated. Pv has a unique feature in its life cycle. Uninucleate sporozoites (spz), after invasion of human hepatocytes, either proceed to develop into tens of thousands of merozoites within the infected hepatocytes or remain as dormant forms called hypnozoites, which cause relapses of malaria months to several years after the primary infection. Elimination of malaria caused by Pv will be facilitated by developing a safe, highly effective drug that eliminates Pv liver stages, including hypnozoites. Identification and development of such a drug would be facilitated by the development of a medium to high throughput assay for screening drugs against Pv liver stages. We undertook the present pilot study to (1) assess the feasibility of producing large quantities of purified, vialed, cryopreserved Pv sporozoites and (2) establish a system for culturing the liver stages of Pv in order to assess the effects of drugs on the liver stages of Pv. We used primaquine (PQ) to establish this assay model, because PQ is the only licensed drug known to clear all Pv hepatocyte stages, including hypnozoites, and the effect of PQ on Pv hepatocyte stage development in vitro has not previously been reported. We report that we have established the capacity to reproducibly infect hepatoma cells with purified, cyropreserved Pv spz from the same lot, quantitate the primary outcome variable of infected hepatoma cells and demonstrate the inhibitory activity of primaquine on the infected hepatoma cells. We have also identified small parasite forms that may be hypnozoites. These data provide the foundation for finalizing a medium throughput, high content assay to identify new drugs for the elimination of all Pv liver stages.
Gold Nanoparticles: Acceptors for Efficient Energy Transfer from the Photoexcited Fluorophores  [PDF]
Debanjana Ghosh, Nitin Chattopadhyay
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.31004
Abstract:

The citrate reduction method of synthesis of gold nanoparticles (AuNP) is standardized with the assistance of instruments like spectrophotometer and TEM. A correlation has been developed between the particle diameter and the fractional concentration of the reductant. This enables one to assess the diameter of the AuNP to be synthesized, in advance, from the composition of the reaction mixture and the diameter of the synthesized particles can be confirmed simply from spectrophotometry. Further, it has been demonstrated that the synthesized AuNPs serve as excellent acceptors for a super-efficient energy transfer (ET) from the donor coumarin 153, leading to a quenching of fluorescence of the latter. The Stern-Volmer constants determined from the fluorescence lifetimes are in the range 107 - 109 mol-1·dm3 and are orders of magnitude higher than the normal photochemical quenching processes. The energy transfer efficiency increases radically with an increase in the size of the metal nanoparticle. The highly efficient energy transfer and the variation of the efficiency of the ET process with a variation of the particle size is ascribed to a large enhancement in the extinction coefficient and an increase in the spectral overlap between the plasmon absorption band of AuNPs and the fluorescence spectrum of C153 with an increase in the size of the nanoparticles. The impact of the work remains in providing a demonstration of a super quenching effect of the AuNPs and projects that they can be exploited for developing biosensors with high degree of sensitivity, if tagged to the biomacromolecules.

Protein Mediated Silica Particles with pH Controlled Porosity and Morphology  [PDF]
Shilpi Show, Brajadulal Chattopadhyay
Advances in Microbiology (AiM) , 2016, DOI: 10.4236/aim.2016.614093
Abstract: Background: The silica leaching activity of some of the mystifying non-pathogenic BKH1 bacteria present in the cluster of hot springs (temperatures range 35°C - 80°C) at Bakreshwar (West Bengal, India, 23°52'48\"N; 87°22'40\"N) has provided some significant advancements in the field of nanotechnology. The present investigation was designed to synthesis the silica particles using bioremediase protein at different pH conditions. Methods: A secretary bacterial protein bioremediase (UniProt Knowledgebase Accession Number P86277) isolated from a thermophilic non-pathogenic bacterium BKH1 (GenBank Accession No. FJ177512) has been used to synthesis the silica particles at different pH conditions (pH at 3.0, 5.0, 8.0, 10.0, and 12.0 respectively). The silica particles were synthesized by the action of bioremediase protein on Tetra-ethyl-orthosilicate (TEOS) under ambient condition. Morphological and compositional studies of the biosynthesized silica particles were characterized by Field emission scanning electron microscope (FE-SEM) equipped with Energy dispersive X-ray analyser (EDX). Results: The Fourier transformed infra-red (FTIR) spectroscopic analysis confirmed the nature as well as occurrence of several functional groups surrounded on the silica particles. The amorphous nature of the prepared silica particles was confirmed by X-ray diffractometer (XRD) study. The Zeta potential (ζ) study revealed the stability of silica particles in neutral pH environment. The Brunauer-Emmett-Teller (BET) surface area measurement confirmed the porosity variation in all biosynthesized silica particles prepared at different pH conditions. Raman spectra analytically depend on their respective specific surface (BET) area. Thermogravimetry tool was used to monitor the effects of the thermal treatment on the surface properties of all the samples. Conclusions: The method for the synthesis of silica particles at different pH condition using the protein bioremediase has a special implication as it is an environmentally benign, cost-effective and facile technique which may have conceivable application in chromatographic packing. In addition, controlling of size as well as porosity of the silica particles can be achievable by pH as an only variable.
Statistics of Projected Motion in One Dimension of a D-Dimensional Random Walker  [PDF]
Jayeeta Chattopadhyay, Muktish Acharyya
Applied Mathematics (AM) , 2018, DOI: 10.4236/am.2018.96042
Abstract:
We are studying the motion of a random walker in generalised d-dimensional continuum with unit step length (up to 10 dimensions) and its projected one dimensional motion numerically. The motion of a random walker in lattice or continuum is well studied in statistical physics but what will be the statistics of projected one dimensional motion of higher dimensional random walker is yet to be explored. Here in this paper, by addressing this particular type of problem, it shows that the projected motion is diffusive irrespective of any dimension; however, the diffusion rate is changing inversely with dimensions. As a consequence, it can be predicted that for the one dimensional projected motion of infinite dimensional random walk, the diffusion rate will be zero. This is an interesting result, at least pedagogically, which implies that though in infinite dimensions there is diffusion, its one dimensional projection is motionless. At the end of the discussion we are able to make a good comparison between projected one dimensional motion of generalised d-dimensional random walk with unit step length and pure one dimensional random walk with random step length varying uniformly between -h to h where h is a “step length renormalizing factor”.
A Simple Model of Currency Notes Withdrawal  [PDF]
Siddhartha Chattopadhyay, Sohini Sahu
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.814198
Abstract: In the backdrop of the demonetization move by the Government of India, this paper proposes a model of optimal currency holding when there is a possibility of currency withdrawal. Our results indicate that if the perceived probability of withdrawal of higher denomination currency is very high, then agents would eventually hold cash in lower denomination currency only, thereby making the higher currency notes redundant. Thus, one of the targets of demonetization, which is less holding of higher currency notes, can be achieved without actually implementing demonetization.
Delineation of Stage Specific Expression of Plasmodium falciparum EBA-175 by Biologically Functional Region II Monoclonal Antibodies
B. Kim Lee Sim,David L. Narum,Rana Chattopadhyay,Adriana Ahumada,J. David Haynes,Steven R. Fuhrmann,Jennifer N. Wingard,Hong Liang,J. Kathleen Moch,Stephen L. Hoffman
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0018393
Abstract: The malaria parasite Plasmodium falciparum EBA-175 binds its receptor sialic acids on glycophorin A when invading erythrocytes. The receptor-binding region (RII) contains two cysteine-rich domains with similar cysteine motifs (F1 and F2). Functional relationships between F1 and F2 domains and characterization of EBA-175 were studied using specific monoclonal antibodies (mAbs) against these domains.
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