Satyabrata Das - Academia.edu (original) (raw)

Papers by Satyabrata Das

Karbala International Journal of Modern Science, 2020

An energy-efficient sensor cloud model is proposed based on the combination of prediction and for... more An energy-efficient sensor cloud model is proposed based on the combination of prediction and forecasting methods. The prediction using Artificial Neural Network (ANN) with single activation function and forecasting using Autoregressive Integrated Moving Average (ARIMA) models use to reduce the communication of data. The requests of the users generate in every second. These requests must be transferred to the wireless sensor network (WSN) through the cloud system in the traditional model, which consumes extra energy. In our approach, instead of one second, the sensors generally communicate with the cloud every 24 hours, and most of the requests reply using the combination of prediction and forecasting methods in the cloud system, which results in less communication and more battery life for the sensor. In our model, we used the ANN model initially, which had predicted the temperature for a given day with an accuracy of 92%. The results of ANN, together with the earlier real temperatures, are given as input to the ARIMA forecasting model, which provides an accuracy of 96% for one day in advance. Our simulation shows that the proposed method saves more energy compared to the traditional approach.

Journal of Sensors, 2018

The sensor cloud is a combination of cloud computing with a wireless sensor network (WSN) which p... more The sensor cloud is a combination of cloud computing with a wireless sensor network (WSN) which provides an easy to scale and efficient computing infrastructure for real-time application. A sensor cloud should be energy efficient as the life of the battery in the sensor is limited and there is a huge consumption of energy in the data centre in running the servers to provide storage. In this paper, we have classified energy-efficient techniques for sensor cloud into different categories and analyzed each technology by using various parameters. Usage percentage of each parameter for every technology is calculated and for all technologies on average is also calculated. From our analysis, we found that most of the energy-efficient techniques ignore quality of service (QoS) parameters, scalability, and network lifetime. Multiparameter optimization including other QoS parameters along with energy may be the future direction of research. Our study will be helpful for researchers to get inf...

The Journal of biological chemistry, Jan 22, 2015

Etv2 is an essential transcriptional regulator of hematoendothelial lineages during embryogenesis... more Etv2 is an essential transcriptional regulator of hematoendothelial lineages during embryogenesis. While Etv2 downstream targets have been identified, little is known regarding the upstream transcriptional regulation of Etv2 gene expression. In the present study, we have established a novel methodology that utilizes the differentiating embryonic stem cell and differentiating embryoid body (ES/EB) system, to define the modules and enhancers embedded within the Etv2 promoter. Using this system, we defined an autoactivating role for Etv2, which is mediated by two adjacent Ets motifs in the proximal promoter. In addition, we have defined the role of VEGF/Flk1-Calcineurin-NFAT signaling cascade in the transcriptional regulation of Etv2. Furthermore, we have defined an Etv2-Flt1-Flk1 cascade, which serves as a negative feedback mechanism to regulate Etv2 gene expression. To complement and extend these studies, we have demonstrated that the Flt1 null embryonic phenotype was partially rescu...

Materials & Design, 2009

Dry sliding wear behaviour of cenosphere reinforced aluminum syntactic foam having density of 1.9... more Dry sliding wear behaviour of cenosphere reinforced aluminum syntactic foam having density of 1.9 g/cc (around 30% porosity) has been studied using a pin-on-disc apparatus at load range of 1-5 kg and sliding velocity of 2-4 m/s. Coefficient of friction and wear rate of the syntactic foam has been compared with that of 10 wt% SiC reinforced aluminum composite. Scanning electron microscope (SEM) is used to characterize the microstructure and the worn surface for examining the wear mechanism. The craters on the specimen surface due to presence of cenosphere play important role in the wear process.

Cancer research, Jan 14, 2015

Ibrutinib (Imbruvica), a small-drug inhibitor of Bruton tyrosine kinase (BTK), is currently under... more Ibrutinib (Imbruvica), a small-drug inhibitor of Bruton tyrosine kinase (BTK), is currently undergoing clinical testing in patients with multiple myeloma, yet important questions on the role of BTK in myeloma biology and treatment are outstanding. Using flow-sorted side population cells from human myeloma cell lines and multiple myeloma primary samples as surrogate for the elusive multiple myeloma stem cell, we found that elevated expression of BTK in myeloma cells leads to AKT/WNT/β-catenin-dependent upregulation of key stemness genes (OCT4, SOX2, NANOG, and MYC) and enhanced self-renewal. Enforced transgenic expression of BTK in myeloma cells increased features of cancer stemness, including clonogenicity and resistance to widely used myeloma drugs, whereas inducible knockdown of BTK abolished them. Furthermore, overexpression of BTK in myeloma cells promoted tumor growth in laboratory mice and rendered side population-derived tumors that contained high levels of BTK more sensitive...

Journal of Stem Cell Research & Therapy, 2012

Introduction: The potential of pluripotent stem cells to be used for cell therapy depends on a co... more Introduction: The potential of pluripotent stem cells to be used for cell therapy depends on a comprehensive understanding of the molecular mechanisms underlying their unique ability to specify cells of all germ layers while undergoing unlimited self-renewal. Alternative splicing and alternate promoter selection contribute to this mechanism by increasing the number of transcripts generated from a single gene locus and thus enabling expression of novel protein variants which may differ in their biological role. The homeodomain-containing transcription factor NANOG plays a critical role in maintaining the pluripotency of Embryonic Stem Cells (ESC). Therefore, a thorough understanding of the transcriptional regulation of the NANOG locus in ESCs is necessary. Methods: Regulatory footprints and transcription levels were identified for NANOG in human embryonic stem cells from data obtained using high-throughput sequencing methodologies. Quantitative real-time PCR following reverse transcription of RNA extracted human ESCs was used to validate the expression of transcripts from a region that extends upstream of the annotated NANOG transcriptional start. Promoter identification and characterization was performed using promoter reporter and electrophoretic mobility shift assays. Results: Transcriptionally active chromatin marking and transcription factor binding site enrichment were observed at a region upstream of the known transcriptional start site in NANOG. Expression of novel transcripts from this transcriptionally active region confirmed the existence of NANOG alternative splicing in human ESCs. We identified an alternate NANOG promoter of significant strength at this upstream region. We also discovered that NANOG autoregulates its expression by binding to its proximal downstream promoter. Conclusion: Our study reveals novel transcript expression from NANOG in human ESCs, indicating that alternative splicing increases the diversity of transcripts originating from the NANOG locus and that these transcripts are expressed by an alternate promoter. Alternative splicing and alternate promoter usage collaborate to regulate NANOG, enabling its function in the maintenance of ESCs.

Transactions of Nonferrous Metals Society of China, 2012

Aluminum−10% TiB master alloy was added in various proportions in 7178 Al alloy in order to exami... more Aluminum−10% TiB master alloy was added in various proportions in 7178 Al alloy in order to examine the effect of TiB on grain refinement, wear and compressive deformation of the later one. Microstructural characterization reveals that TiB particles act as grain refiners for primary base alloy and result in globular dendrites. It was observed that the wear resistance and strength of the alloy decreased when the master alloy addition increased beyond 20%, even though the dendrites become much finer and almost spherical in nature.

Materials Science and Engineering: A, 2006

The influence of material related parameters such as alloy composition and reinforcement volume f... more The influence of material related parameters such as alloy composition and reinforcement volume fraction and the experimental parameters such as the slurry concentration and rotational speed on the erosion-corrosion behavior of SiC particle reinforced aluminum alloy composites in saline, acidic and basic environments is studied. It is observed that 2014-SiC composite exhibited better wear resistance than LM13-SiC composite in acidic and NaCl media. Further both the composites exhibited better wear resistance than their matrix alloys in these environments irrespective of the sand content in the slurry and the rotational speed. The wear rates increased with increasing sand content in both the media. Al/Si/precipitate interfaces were found to be the preferential sites for corrosive attack in both the alloys and composites. In basic media the trend was reversed with both the composites exhibiting lower wear resistance than their matrix alloys. Further 2014-SiC composite exhibited lower wear resistance than LM13-SiC composite in basic media.

Materials Science and Engineering: A, 2014

The compressive deformation behavior of aluminum cenosphere syntactic foams of varying densities ... more The compressive deformation behavior of aluminum cenosphere syntactic foams of varying densities and cenosphere sizes have been studied at different strain rates (from 0.01/s to 10/s). The plateau stress, densification strain, energy absorption and strain rate sensitivity parameter as a function of relative density, strain rate and cenosphere size have been examined. Densification strain is found to be almost invariant to relative density, strain rate and cenosphere size. But, the plateau stress and energy absorption of syntactic foams are influenced by the relative density and cenosphere size. However, plateau stress is found to be almost invariant to the strain rate. The energy absorption is marginally higher in case of syntactic foam with coarser cenosphere at higher strain rate, whereas reverse is true at lower strain rate. This is attributed to the differences in deformation mechanism at different strain rates.

Materials Science and Engineering: A, 2009

In this study, the crush behaviour and the energy absorption capability of an aluminium honeycomb... more In this study, the crush behaviour and the energy absorption capability of an aluminium honeycomb core is discussed. A three-dimensional finite-element model of a honeycomb-core structure was developed using the commercial code Abaqus. Flatwise and edgewise experimental compressive tests were made to validate the numerical model and good agreement was found between the experimental data and the numerical results. Virtual compressive tests varying the cell size, cell-wall thickness, and material properties were performed. The deformation mode, compressive core behaviour and its energy-absorption capacity were examined. The crushing parameters at in-plane directions were more affected by the variations of the characteristic core parameters; although, in general, increasing the cell-wall thickness and the yield stress of the aluminium alloy give higher crush loads, and therefore the absorbed energy increases. However, if the cell size increases, the energy-absorption capacity decreases.

Blood, 2013

Key Points RARα2 activates Wnt and hedgehog pathways in maintaining myeloma stem cell features an... more Key Points RARα2 activates Wnt and hedgehog pathways in maintaining myeloma stem cell features and drug resistance.

Archives of Ophthalmology, 2009

To determine if loss of protein kinase C␥ (PKC␥) results in increased structural damage to the re... more To determine if loss of protein kinase C␥ (PKC␥) results in increased structural damage to the retina by hyperbaric oxygen (HBO), a treatment used for several ocular disorders. Methods: Six-week-old mice were exposed in vivo to 100% HBO 3 times a week for 8 weeks. Eyes were dissected, fixed, embedded in Epon, sectioned, stained with toluidine blue O, and examined by light microscopy. Results: The thicknesses of the inner nuclear and ganglion cell layers were increased. Destruction of the outer plexiform layer was observed in the retinas of the PKC␥knockout mice relative to control mice. Exposure to HBO caused significant degradation of the retina in knockout mice compared with control mice. Damage to the outer segments of the photoreceptor layer and ganglion cell layer was apparent in central retinas of HBO-treated knockout mice. Conclusions: Protein kinase C␥-knockout mice had increased retinal sensitivity to HBO. Results demonstrate that PKC␥ protects retinas from HBO damage. Clinical Relevance: Care should be taken in treating patients with HBO, particularly if they have a genetic disease, such as spinocerebellar ataxia type 14, a condition in which the PKC␥ is mutated and nonfunctional.

Applied Geochemistry, 2022

$Research paper thumbnail of Performances comparison of nonlinear hydrodynamic journal bearing with rotor internal damping using optimal and fractional order controllers$

2017 IEEE Calcutta Conference (CALCON), 2017

Hydrodynamic journal bearings are one of the most widely used bearings to support the rotating sh... more Hydrodynamic journal bearings are one of the most widely used bearings to support the rotating shafts. Rotating machines have a number of complicated accessories attached with it and they are also made extremely flexible. Rotating machines are also required to run at higher speed, much higher than their first threshold speed. Rotor-hydrodynamic journal bearing systems exhibit different kinds of phenomena pertaining to its operations. Hydrodynamic journal bearing and integrated model tends to be unstable due to nonconservative nature of hydrodynamic forces and stiffness coefficients. First, we linearized the non-linear system using state feedback linearization. Second, optimal and fractional order control methods are used for stabilizing the integrated system. Modeling and simulation are done by using MATLAB-Simulink programming. The performances are discussed for both cases.

Proceedings of the National Academy of Sciences, 2020

International Journal of Materials Research, 2019

The microstructure, mechanical, and high-stress abrasive wear of as-cast and heat-treated LM25-Si... more The microstructure, mechanical, and high-stress abrasive wear of as-cast and heat-treated LM25-SiC composites were compared with those of a matrix alloy and a low-cost hypereutectic alloy (LM30). The microstructure of the composite exhibits uniformly dispersed SiC particles and good interfacial bonding between the SiC particles and the matrix. Heat treatment caused the needle-shaped silicon to become spherical and improved the homogeneity of its dispersion in the matrix. The hardness, ultimate tensile strength, yield strength, and wear resistance of the materials were improved, but the elongation was reduced as a result of the heat treatment. The wear rate and friction coefficient of the materials decreased as the sliding distance increased for both the as-cast and heat-treated samples. The wear surface morphology and wear debris analyses were performed by using high-resolution field emission scanning electron microscopy.

Materials Sciences and Applications, 2016

For the first time in the world advanced multi layered Red Mud and MWCNTs (ARMC) based EMI shield... more For the first time in the world advanced multi layered Red Mud and MWCNTs (ARMC) based EMI shielding material has been developed at CSIR-AMPRI, Bhopal. Red mud provides oxides of titanium and iron as precursor and the MWCNTs provides electrical conductivity characteristics necessary for making desired EMI shielding materials. The novel process involves unique designing of chemical compositions and mineralogical phases of red mud, MWCNTs together with appropriate additive and solvent which results in the simultaneous and synergistic chemical reactions among various constituents thereby forming tailored precursor powder. Further, the ceramic processing of tailored precursor powder in appropriate environment enables formation of advanced ARMC shielding material having a variety of ceramic phases with multi elemental compositions and multi layered crystal structures. The synthesized material was characterized by various techniques namely XRD, PL, FESEM, EDXA. The reflection loss (R. L.) of the sample was calculated based on the measured complex permittivity and permeability. The advanced ARMC material with thickness t = 1.5 mm showed a minimum R. L. of −35.5 Db at 14.0 GHz with a response band width of 1.8 GHz. Thus, the developed advanced ARMC material acts as a good EMI wave absorber.

International Journal of Medical Research & Health Sciences, 2014