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匹配条件: “ Sunita Biswas” ,找到相关结果约2081条。
Sensory Regulation of Neuroligins and Neurexin I in the Honeybee Brain
Sunita Biswas,Judith Reinhard,John Oakeshott,Robyn Russell,Mandyam V. Srinivasan,Charles Claudianos
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0009133
Abstract: Neurexins and neuroligins, which have recently been associated with neurological disorders such as autism in humans, are highly conserved adhesive proteins found on synaptic membranes of neurons. These binding partners produce a trans-synaptic bridge that facilitates maturation and specification of synapses. It is believed that there exists an optimal spatio-temporal code of neurexin and neuroligin interactions that guide synapse formation in the postnatal developing brain. Therefore, we investigated whether neuroligins and neurexin are differentially regulated by sensory input using a behavioural model system with an advanced capacity for sensory processing, learning and memory, the honeybee.
Congenital malaria with atypical presentation: A case report from low transmission area in India
Neena Valecha, Sunita Bhatia, Sadhna Mehta, Sukla Biswas, Aditya P Dash
Malaria Journal , 2007, DOI: 10.1186/1475-2875-6-43
Abstract: An infant is described who presented with irritability and feeding problems. Clinical examination and investigations revealed that the infant was afebrile, had jaundice, hepatosplenomegaly and haemolytic anaemia. Peripheral smear demonstrated Plasmodium vivax. While the mother had significant levels of immunoglobulin G (IgG), the infant was found negative for IgG and had low immunoglobulin M (IgM) levels. The mother had a history of febrile illness during pregnancy and her peripheral smear was also positive for P. vivax. Both were successfully treated with chloroquine in the dose of 25 mg/kg/day over three days.The case emphasizes the importance of considering the diagnosis of malaria even in infants in low transmission area, who may not present with typical symptoms of malaria, such as fever, but have other clinical manifestations like jaundice and haemolytic anaemia.Congenital malaria can be acquired by transmission of parasites from mother to child during pregnancy or perinataly during labour [1]. Congenital malaria has been documented for many years but it was previously thought to be uncommon specially in indigenous populations [2]. More recent studies, however, suggest that incidence has increased and values between 0.3 to 33% have been observed from both endemic and non-endemic areas [2]. Mukthar et al. [3] attribute the higher incidence to an increased resistance and virulence of parasite resulting from altered antigenic determinants in addition to increased reporting. Although placental infections with Plasmodium falciparum have been described, the role of other species especially Plasmodium vivax, which exists in good proportion in some countries, including India, is not known. In a study conducted in central India although 2.2% (4/182) women were placenta positive for P. vivax or mixed infection, but none of the infants developed parasitaemia up to 6 months of age [4].Children with congenital malaria can present with fever, irritability, feeding problems,
Bridging the Synaptic Gap: Neuroligins and Neurexin I in Apis mellifera
Sunita Biswas, Robyn J. Russell, Colin J. Jackson, Maria Vidovic, Olga Ganeshina, John G. Oakeshott, Charles Claudianos
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0003542
Abstract: Vertebrate studies show neuroligins and neurexins are binding partners in a trans-synaptic cell adhesion complex, implicated in human autism and mental retardation disorders. Here we report a genetic analysis of homologous proteins in the honey bee. As in humans, the honeybee has five large (31–246 kb, up to 12 exons each) neuroligin genes, three of which are tightly clustered. RNA analysis of the neuroligin-3 gene reveals five alternatively spliced transcripts, generated through alternative use of exons encoding the cholinesterase-like domain. Whereas vertebrates have three neurexins the bee has just one gene named neurexin I (400 kb, 28 exons). However alternative isoforms of bee neurexin I are generated by differential use of 12 splice sites, mostly located in regions encoding LNS subdomains. Some of the splice variants of bee neurexin I resemble the vertebrate α- and β-neurexins, albeit in vertebrates these forms are generated by alternative promoters. Novel splicing variations in the 3′ region generate transcripts encoding alternative trans-membrane and PDZ domains. Another 3′ splicing variation predicts soluble neurexin I isoforms. Neurexin I and neuroligin expression was found in brain tissue, with expression present throughout development, and in most cases significantly up-regulated in adults. Transcripts of neurexin I and one neuroligin tested were abundant in mushroom bodies, a higher order processing centre in the bee brain. We show neuroligins and neurexins comprise a highly conserved molecular system with likely similar functional roles in insects as vertebrates, and with scope in the honeybee to generate substantial functional diversity through alternative splicing. Our study provides important prerequisite data for using the bee as a model for vertebrate synaptic development.
Distinct Early Molecular Responses to Mutations Causing vLINCL and JNCL Presage ATP Synthase Subunit C Accumulation in Cerebellar Cells
Yi Cao,John F. Staropoli,Sunita Biswas,Janice A. Espinola,Marcy E. MacDonald,Jong-Min Lee,Susan L. Cotman
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017118
Abstract: Variant late-infantile neuronal ceroid lipofuscinosis (vLINCL), caused by CLN6 mutation, and juvenile neuronal ceroid lipofuscinosis (JNCL), caused by CLN3 mutation, share clinical and pathological features, including lysosomal accumulation of mitochondrial ATP synthase subunit c, but the unrelated CLN6 and CLN3 genes may initiate disease via similar or distinct cellular processes. To gain insight into the NCL pathways, we established murine wild-type and CbCln6nclf/nclf cerebellar cells and compared them to wild-type and CbCln3Δex7/8/Δex7/8 cerebellar cells. CbCln6nclf/nclf cells and CbCln3Δex7/8/Δex7/8 cells both displayed abnormally elongated mitochondria and reduced cellular ATP levels and, as cells aged to confluence, exhibited accumulation of subunit c protein in Lamp 1-positive organelles. However, at sub-confluence, endoplasmic reticulum PDI immunostain was decreased only in CbCln6nclf/nclf cells, while fluid-phase endocytosis and LysoTracker? labeled vesicles were decreased in both CbCln6nclf/nclf and CbCln3Δex7/8/Δex7/8 cells, though only the latter cells exhibited abnormal vesicle subcellular distribution. Furthermore, unbiased gene expression analyses revealed only partial overlap in the cerebellar cell genes and pathways that were altered by the Cln3Δex7/8 and Cln6nclf mutations. Thus, these data support the hypothesis that CLN6 and CLN3 mutations trigger distinct processes that converge on a shared pathway, which is responsible for proper subunit c protein turnover and neuronal cell survival.
Pattern Formation in Tri-Trophic Ratio-Dependent Food Chain Model  [PDF]
Dawit Melese, Sunita Gakkhar
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.212213
Abstract: In this paper, a spatial tri-trophic food chain model with ratio-dependent Michaelis-Menten type functional response under homogeneous Neumann boundary conditions is studied. Conditions for Hopf and Turing bifurcation are derived. Sufficient conditions for the emergence of spatial patterns are obtained. The results of numerical simulations reveal the formation of labyrinth patterns and the coexistence of spotted and stripe-like patterns.
Pressure Sensor Based on Mechanically Induced LPFG in Novel MSM Fiber Structure  [PDF]
Sunita Ugale, Vivekanand Mishra
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.33036

We have proposed and demonstrated experimentally a novel and simple pressure sensor based on mechanically induced long period optical fiber gratings. We report here for the first time to our knowledge the characterization of mechanically induced long period fiber gratings in novel multimode-singlemode-multimode fiber structure. The MLPFG induced in single mode fiber and multimode fibers are studied separately and the results are compared with MLPFG induced in MSM fiber structure. MLPFG in MSM structure has much greater sensitivity. We have obtained maximum transmission loss peak of around 18 dB, and the sensitivity of pressure sensor is 8 dB/Kg.

Nitrogen and Boron Doped Diamond Like Carbon Thin Films Synthesis by Electrodeposition from Organic Liquids and Their Characterization  [PDF]
Sunita Kundoo, Satyajit Kar
Advances in Materials Physics and Chemistry (AMPC) , 2013, DOI: 10.4236/ampc.2013.31005

Thin films of amorphous diamond like carbon (a:DLC) were deposited by using a novel technique. By electrodeposition from methanol-camphor solution thin a:DLC films were deposited on non-conductive glass substrates and also on high resistive Si substrates, by using a fine wire mesh electrode, at atmospheric pressure and temperature below 350 K. Thin films of a:DLC were doped by incorporation of nitrogen (a:N-DLC) and boron (a:B-DLC) using urea and boric acid with methanol-camphor solution respectively during the electrodeposition process. From transmittance measurements in the UV-VIS-NIR region, the optical energy band gap of about 1.0 eV for undoped a:DLC film, 2.12 eV for a:N-DLC and 2.0 eV for a:B-DLC films were determined. The spectra showed high transparency in the visible and NIR region. Fourier transform infrared spectroscopy (FTIR) measurements showed the appearance of various C-H and C-C bonding in the spectrum of undoped amorphous DLC film and confirmed C-N and C=N bond formation in a:N-DLC film. From the temperature variation of d.c. conductivity studies, the activation energies were determined and found to be 0.75 eV, 0.32 eV and 0.58 eV for undoped a:DLC films, a:N-DLC and a:B-DLC films respectively. Electrical resistivity at room temperature was reduced by the doping effect, from 109 Ω-cm for undoped films to 107 Ω-cm for nitrogen doped films and 108 Ω-cm for boron doped films.

Deformation of a two-phase medium due to a long buried strike-slip fault  [PDF]
Sunita Rani, Neeru Bala
Natural Science (NS) , 2013, DOI: 10.4236/ns.2013.510132

The aim of the present paper is to obtain the two-dimensional deformation of a two-phase elastic medium consisting of half-spaces of different ri- gidities in welded contact due to a buried long strike-slip fault. The solution is valid for arbitrary values of the fault-depth and the dip angle. The effect of fault-depth on the displacement and stress fields for different values of dip angle has been studied numerically. It is found that the displacement field varies significantly for a buried fault from the corresponding displacement field for an interface-breaking fault. The contour maps showing the stress field for various dip angles for buried and interface-breaking fault have been plotted. It has been observed that the stress field varies significantly for a buried fault from the corresponding stress field for an interface-breaking fault.

An Exact Scalar Field Inflationary Cosmological Model Which Solves Cosmological Constant Problem, Dark Matter Problem and Other Problems of Inflationary Cosmology  [PDF]
Debasis Biswas
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.48A017

An exact scalar field cosmological model is constructed from the exact solution of the field equations. The solutions are exact and no approximation like slow roll is used. The model gives inflation, solves horizon and flatness problems. The model also gives a satisfactory estimate of present vacuum energy density as well as vacuum energy density at Planck epoch and solves cosmological constant problem of 120 orders of magnitude discrepancy of vacuum energy density. Further, this model predicts existence of dark matter/energy and gives an extremely accurate estimate of present energy density of dark matter and energy. Along with explanations of graceful exit, radiation era, matter domination, this model also indicates the reason for present accelerated state of the universe. In this work a method is shown following which one can construct an infinite number of exact scalar field inflationary cosmological models.

Outcomes of antiretroviral therapy in a northern Indian urban clinic
Sharma,Surendra K; Dhooria,Sahajal; Prasad,KT; George,Ninoo; Ranjan,Sanjay; Gupta,Deepak; Sreenivas,Vishnubhatla; Kadhiravan,Tamilarasu; Miglani,Sunita; Sinha,Sanjeev; Wig,Naveet; Biswas,Ashutosh; Vajpayee,Madhu;
Bulletin of the World Health Organization , 2010, DOI: 10.1590/S0042-96862010000300017
Abstract: problem: antiretroviral therapy (art) programmes have been successful in several countries. however, whether they would succeed as part of a national programme in a resource-constrained setting such as india is not clear. the outcomes and specific problems encountered in such a setting have not been adequately studied. approach: we assessed the efficacy and functioning of india's national art programme in a tertiary care centre in northern india. all art-naive patients started on art between may 2005 and october 2006 were included in the study and were followed until 31 april 2008. periodic clinical and laboratory evaluations were carried out in accordance with national guidelines. changes in cd4+ lymphocyte count, body weight and body mass index were assessed at follow-up, and the operational problems analysed. local setting: the setting was a tertiary care centre in northern india with a mixed population of patients, mostly of low socioeconomic status. the centre is reasonably well resourced but faces constraints in health-care delivery, such as lack of adequate human resources and a high patient load. relevant changes: the response to art in the cohort studied was comparable to that reported from other countries. however, the programme had a high attrition rate, possibly due to patient-related factors and operational constraints. lessons learnt: a high rate of attrition can affect the overall efficacy and functioning of an art programme. addressing the issues causing attrition might improve patient outcomes in india and in other resource-constrained countries.

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