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OALib Journal期刊

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Prediction of the Fragmentation Pathway of Atorvastatin De-Protonated Ion  [PDF]
Dev Kant Shandilya, Rekha Israni, Peter Edward Joseph
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104547
Abstract:
Introduction: A fragmentation pathway of atorvastatin de-protonated ion was proposed based on rational interpretation workflows. Method: The mass spectral data (MS, MS/MS and MS3) of atorvastatin was obtained by electrospray negative ionization mode with flow injection analysis; using liquid chromatography systems coupled with tandem mass spectrometers (Q-trap and Q-ToF). Results: The fragmentation pathway was established using fragment ions of de-protonated ion; elemental composition, molecular structure and mechanism of formation for each major fragment presented. Pathway was proposed based on the MS3 spectral data in combination with basic interpretation rules and rational workflows. Conclusion: This study and data interpretation workflows can be useful for writing fragmentation pathway, mechanism for formation of fragments, and can be applied for mass spectral data interpretation of similar small organic molecules.
Prediction of the Fragmentation Pathway of Valsartan Protonated Ion  [PDF]
Dev Kant Shandilya, Rekha Israni, Peter Edward Joseph
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104764
Abstract:
Introduction: A fragmentation pathway of valsartan protonated ion proposed based on rational interpretation workflows. Method: The mass spectral data (MS, MS/MS, and MS3) of valsartan protonated ion, were attained by electrospray positive ionization with flow injection analysis; using liquid chromatography systems hyphenated with hybrid tandem mass spectrometer (Q-trap). Results: The pathway of fragmentation was established using product ions of the protonated ion; elemental composition, molecular structure and mechanism of formation for significant product ions were proposed. A pathway was proposed based on the MS/MS and MS3 spectral data in combination with basic interpretation rules and rational workflows. Conclusion: Workflow used for data interpretation can be useful for writing the fragmentation pathway, a mechanism for the formation of fragments, and can be applied for mass spectral data interpretation of similar small organic molecules.
Prediction of the Fragmentation Pathway of Atorvastatin by Using High Resolution Collision Induced Dissociation (HR-MS/MS) Spectral Information  [PDF]
Dev Kant Shandilya, Rekha Israni, Peter Edward Joseph, Venkata Siva Satyanarayana Kantamreddi
Open Access Library Journal (OALib Journal) , 2017, DOI: 10.4236/oalib.1103473
Abstract:
Introduction: A possible fragmentation pathway of atorvastatin was proposed based on rational interpretation of high resolution collision induced dissociation (CID) fragmentation spectral data. Method: The mass spectral (MS and MS/MS) data of atorvastatin was obtained by using a flow injection analysis, LC coupled with high resolution mass analyzer system with Q-TOF technology. Results: The elemental composition for each major fragment was proposed with a calculated mass error in parts per million (ppm). The mass error found in this study is from 0.3 to 5.7 ppm; strongly supports all the proposed elemental composition of fragments. Based on the fragments, possible fragmentation pathway was proposed. Conclusion: The workflow followed for interpretation can also address the structural possibilities of similar type of small organic molecules.
Identification of Oxidative Degradation Products of Lansoprazole by Using High Resolution Mass Spectrometry Spectral Data  [PDF]
Dev Kant Shandilya, Rekha Israni, Peter Edward Joseph, Anoop Kumar, Manoj Pillai
International Journal of Analytical Mass Spectrometry and Chromatography (IJAMSC) , 2017, DOI: 10.4236/ijamsc.2017.53004
Abstract:
The study focused on the application of high-resolution mass spectrometry for the identification of impurities in pharmaceutical small molecules. A high-performance liquid chromatography (HPLC) coupled high resolution mass spectrometer (HRMS) was used for identification of oxidative degradation impurities (DIs) of lansoprazole. The utilization of HRMS facilitates to determine the accurate mass of impurities and their fragment/product ions. A fast mass spectrometer (MS) compatible reverse phase chromatography method was used to investigate the oxidative stressed impurities. HPLC column; C18 (50 × 4.6 mm, 3.5 μm) was used with gradient elution. Spectral data acquired using information dependent acquisition (IDA) with real time dynamic background subtraction algorithm (DBS). Three oxidative impurities: DI-I (m/z 386.0781), DI-II (m/z 402.0734) and DI-III (m/z 386.0785), was observed during this study; interpretation of high resolution spectral data of all three impurities was carried out; elemental composition and molecular structure was proposed for major fragments. In this study mass error was found ≤7.7 parts per million (ppm).
Constant Modulus Blind Equalization for Time-Varying MIMO-FIR Channels with Pulse Estimation
Rekha
International Journal of Advanced Computer Research , 2012,
Abstract: The constant modulus (CM) property of sourcesignal can be mostly utilized to equalize the singleinputmultiple-output and finite impulse response(FIR) channels. In existing, the channels areblindly equalized and the equalization methods arebased on higher order statistics that estimates allnon-zero channel pulsation under time-invarianceassumption. However, the assumption cannot besatisfied time varying multiple input multiple output(MIMO) applications ex. Mobile communication. Inthis paper, the proposed algorithm which extendsthe CM criterion to blind equalization usingcomplex exponential basic expansion model (CEBEM)and the channel is assumed as time varyingMIMO-FIR. The method only employ the Secondorder statistics (SOS) and finally, it estimates onlyone pulsation. In this way, the system increases theSNR of the transmitted symbols and produces mostbeneficial result in time-varying channels. The fastconvergence is also achieved through zero forcingequalization.
Mathematical Model of Blood Flow in Small Blood Vessel in the Presence of Magnetic Field  [PDF]
Rekha Bali, Usha Awasthi
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.22031
Abstract: A mathematical model for blood flow in the small blood vessel in the presence of magnetic field is presented in this paper. We have modeled the two phase model for the blood flow consists of a central core of suspended erythrocytes and cell-free layer surrounding the core. The system of differential equations has been solved analytically. We have obtained the result for velocity, flow rate and effective viscosity in presence of peripheral layer and magnetic field .All the result has been obtained and discussed through graphs.
A Casson Fluid Model for Multiple Stenosed Artery in the Presence of Magnetic Field  [PDF]
Rekha Bali, Usha Awasthi
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.35066
Abstract: The flow of blood through a multistenosed artery under the influence of external applied magnetic field is studied. The artery is modeled as a circular tube. The effect of non-Newtonian nature of blood in small blood vessels has been taken into account by modeling blood as a Casson fluid. The effect of magnetic field, height of stenosis, parameter determin- ing the shape of the stenosis on velocity field, volumetric flow rate in stenotic region and wall shear stress at surface of stenosis are obtained and shown graphically. Some important observations regarding the flow of blood in multi stenosed artery are obtained leading to medical interest.
Near-Lossless Compression Based on a Full Range Gaussian Markov Random Field Model for 2D Monochrome Images  [PDF]
K. Seetharaman, V. Rekha
Journal of Signal and Information Processing (JSIP) , 2013, DOI: 10.4236/jsip.2013.41002
Abstract:

This paper proposes a Full Range Gaussian Markov Random Field (FRGMRF) model for monochrome image compression, where images are assumed to be Gaussian Markov Random Field. The parameters of the model are estimated based on Bayesian approach. The advantage of the proposed model is that it adapts itself according to the nature of the data (image) because it has infinite structure with a finite number of parameters, and so completely avoids the problem of order determination. The proposed model is fitted to reconstruct the image with the use of estimated parameters and seed values. The residual image is computed from the original and the reconstructed images. The proposed FRGMRF model is redefined as an error model to compress the residual image to obtain better quality of the reconstructed image. The parameters of the error model are estimated by employing the Metropolis-Hastings (M-H) algorithm. Then, the error model is fitted to reconstruct the compressed residual image. The Arithmetic coding is employed on seed values, average of the residuals and the model coefficients of both the input and residual images to achieve higher compression ratio. Different types of textured and structured images are considered for experiment to illustrate the efficiency of the proposed model. The results obtained by the FRGMRF model are compared to the JPEG2000. The proposed approach yields higher compression ratio than the JPEG whereas it produces Peak Signal to Noise Ratio (PSNR) with little higher than the JPEG, which is negligible.

Digital Circuits Implementation On Rpga Simulator
Pankaj Kumar Israni,S. C. Jain
Computer Science , 2013,
Abstract: For Reversible computing, Target technology is yet to become available. Adequate tools are not yet developed for reversible technology. Simulation is still under development. Classical logic synthesis methods and simulation tools can not be used in reversible computing. Because these work on irreversible logic blocks but in reversible computing reversible logic blocks are used for design and implementation. So, we need a simulation platform to analysis and development in this area. So, we worked on this area and developed a GUI based simulator. In the Dissertation work, we undertook simulation of RPGA, reversible alternative to FPGA. We developed a RPGA simulator in our project. RPGA simulator combines the technology of PLD/FPGA/SYSTOLIC array. Our RPGA simulator, implements a given symmetric reversible Circuit on a RPGA structure. We also worked on RPGA structure gates (picton and kerntopf gates) to develop a better RPGA structure. Stepwise execution on RPGA structure is also performed in RPGA simulator. We also designed new algorithms for Truth Table generation and symmetry analysis. The dissertation work aims to develop entire simulator is GUI based and easy to learn that makes it user friendly. User can easily view all simulation results in GUI of our RPGA simulator.
Boundary Layer Flow past a Stretching Cylinder and Heat Transfer with Variable Thermal Conductivity  [PDF]
Rekha R. Rangi, Naseem Ahmad
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.33032
Abstract: The boundary layer flow of viscous incompressible fluid over a stretching cylinder has been considered to study flow field and temperature field. Due to non-linearity, a numerical approach called Keller-box technique has been used to compute the values of velocity function f and temperature field at different points of dynamic region. The expressions for skin friction and Nusselt number have also been obtained. The dependence of velocity profile and temperature profile on the dimensionless parameter of practical interest has been analyzed in detail by graphs. The dependence of Skin friction and Nusselt number has been seen through tables.
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