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Search Results: 1 - 10 of 50876 matches for " Y.?Aparna "
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A New and Enantioselective Chromatographic Method for Linagliptin on Amylose Coated Chiral Stationary Phase  [PDF]
Cholleti Vijay Kumar, Pasula Aparna, Pavan Kumar Vasa, Y. Ravindra Kumar, Nitin Haridas Dhekale
American Journal of Analytical Chemistry (AJAC) , 2016, DOI: 10.4236/ajac.2016.77051
Abstract: A new and enantioselective liquid chromatographic method was developed for estimation of S-Linagliptin in Linagliptin (LINA) drug substances. The desired enantiomeric separation was achieved on Chiralpak AD-H (250*4.6 mm*5 μm) column with the mobile phase composition of ethanol, methanol and diethylamine in a ratio of 90:10:0.1 (v/v/v) with flow rate of 0.5 mL·min-1 and column oven temperature 30°C and the eluted compounds were monitored at 225 nm. In the proposed chiral method, USP resolutions between both the enantiomers were more than 5.0. Limit of detection and Limit of quantitation of S-LINA was found to be 0.03 μg·mL-1 and 0.10 μg·mL-1 respectively. Linearity study was conducted from LOQ to 150% and correlation coefficient found to be 0.9997. Accuracy was within the range of 98.6% to 101.5%. To prove selectivity power of the method specificity study was conducted by subjecting drug substance to acid, base, hydrolysis, oxidation and photolysis and ensured the peak purity of analyte in degraded samples. Moreover, the method has been fully validated as per ICH guidelines. The proposed method is precise, accurate, linear, rugged, robust and suitable for accurate quantification of S-LINA in LINA drug substance.
Enantiomeric Separation of S-Epichlorohydrin and R-Epichlorohydrin by Capillary Gas Chromatography with FID Detector  [PDF]
Cholleti Vijay Kumar, Pavan Kumar Vasa, Y. Ravindra Kumar, Pasula Aparna, Padi Pratyusha
American Journal of Analytical Chemistry (AJAC) , 2016, DOI: 10.4236/ajac.2016.711069
Abstract: The aim of this study was to develop a simple and derivatization free method for the Quantification of S-Epichlorohydrin in R-Epichlorohydrin by using a gas chromatography coupled with flame ionization detector (FID). Enantiopure epichlorohydrin was a valuable epoxide key starting material for preparing optically active Rivaroxaban. The enantiomeric separations of S-Epichlorohydrin and R-Epichlorohydrin were achieved on Gamaa-Dex-225 (30 meters × 0.25 mm I.D, 0.25 μm) column with a total run time of 30 min. Nitrogen was used as a carrier gas with constant pressure 25.0 psi. The critical experimental parameters such as, column selection, flow rate, injection volume and diluent were studied and optimized. Excellent correlation coeffient between peak responses and concentrations was >0.9998. The recoveries of S-Epichlorohydrin spiked in R-Epichlorohydrin were in the range from 98.2% to 102.8%. Limit of quantitation for S-Epichlorohydrin was sufficiently lower than limits specified by ICH. The method has validated as per International Conference on Harmonization (ICH) guidelines. A precise, accurate, linear and robust Gas Chromatography method was developed for the quantification of S-Epichlorohydrin in R-Epichlorohydrin for Rivaroxaban.
Health expenditures and personal bankruptcies  [PDF]
Aparna Mathur
Health (Health) , 2012, DOI: 10.4236/health.2012.412192
Abstract: Using household-level data from the Panel Study of Income Dynamics, we estimate the extent to which medical expenses are responsible for driving households to bankruptcy. Our results suggest that an increase of 10 percent in medical debts would cause a 27 percent increase in the filing propensity of households with primarily medical debt, and an approximately 36 percent increase in filing propensity of households where medical debts co-exist with primarily credit card debts. Studying the post-bankruptcy scenario, we find that filers are 19 percent less likely to own a home even several years after the filing, compared to non-filers. However, the consequences are less adverse for medical filers i.e. those who filed due to high medical bills compared to other filers.
Industrial Unsustainability  [PDF]
Aparna Nayak
Journal of Geoscience and Environment Protection (GEP) , 2015, DOI: 10.4236/gep.2015.34003
Abstract: The development of unconventional gas exploration in the USA, in particular shale gas, caused a revolution in the American and the global gas markets. The regional-wide use of unconventional gas resources could stabilize the natural gas demand and the energy supply security of European and Asian countries. But traditionally, almost all gas contracts in Europe and Asia are linked to oil because of the demand for stable, long-term contracts. Furthermore, in many Asian countries, large state-owned enterprises dominate their national gas markets, leading to little competition and incentives to reduce gas prices. In Europe, the expansion of unconventional gas is facing grassroots opposition from environmental groups who are concerned about ground water safety, adequate waste water management, seismic events and greenhouse gas emissions. In this article, I will discuss the rapidly changing natural gas markets and the role and prospects of unconventional gas as well as its environmental impacts and unsustainability in industry level.
Clean India  [PDF]
Aparna Nayak
Journal of Geoscience and Environment Protection (GEP) , 2015, DOI: 10.4236/gep.2015.35015
Abstract: Mahatma Gandhi was mindful of the poor position of Indian rural people at that time and he dreamt of a cleaner India, where he emphasized on cleanliness and sanitation as an intact function of surviving. President Pranab Mukherjee in his address to Parliament in June 2014, said, “For ensuring hygiene, waste management and sanitation across the nation a “Swachh Bharat Mission” will be established. This will be our tribute to Mahatma Gandhi on his 150th birth anniversary to be celebrated in the year 2019”. The Narendra Modi Government will shortly establish the “Swachh Bharat” movement to solve the sanitation problem in India, to solve the problem of waste management and make India a clean state, ensuring hygiene all across the nation. Emphasizing “Clean India” on August 15, 2014 in his Independence Day speech, the Prime Minister said that this trend is linked with the economic activity of the state. This missionary work for creating a clean India will be launched on October 2, 2014, the birth anniversary of Mahatma Gandhi with the objective of completing the mission in 2019, the 150th birth anniversary of the father of the country.
Dicephalus dipus tribrachius: A case report of unusual conjoined twins
Aparna C,Renuka I,Sailabala G,Nayudamma Y
Indian Journal of Pathology and Microbiology , 2010,
Abstract: A conjoined twin is a rarity. It occurs 1 in 50,000 to 1 in 2,00,000 fetuses. Forty percent of the conjoined twins are stillborn and an additional one-third die within 24 h of birth. They result from late twinning events about 14th day after fertilization. We report a case of stillborn conjoined twins sent for autopsy. The bodies of the fetuses were fused from the thorax to the pelvis. There were two heads, three upper limbs and two lower limbs, with fusion of the thoracic, abdominal and pelvic regions. On systemic examination, some organs were fused and some were separate. A multilocular cyst with milky fluid was seen in the pelvic region. This case is reported in view of its rarity.
Preparation and Characterization of CuO Nanoparticles by Novel Sol-Gel Technique
Y.?Aparna,K.?Venkateswara Rao,P.?Srinivasa Subbarao
Journal of Nano- and Electronic Physics , 2012,
Abstract: Recent developments of nanosize materials of metal and metal oxide particles are intensively pursued because of their prominence in different fields of applications. Among all the transition metal oxides, CuO is a potential candidate for the application of magnetic storage devices, solar energy transfer, sensors, and super capacitors etc. Moreover CuO nanoparticles act as a good catalyst in some of the chemical reactions. CuO nanoparticles were prepared by novel sol-gel method. In this technique CuCl2.6H2O is added with acetic acid and heated to 100 °C with continuous stirring. To control the ph of the above solution, NaOH is added to the solution till ph reached desired value. The color of the solution changed from blue to black with precipitation. The black precipitation was washed 3 – 4 times with distilled water. Finally the solution was centrifuged and dried in air for one day. The CuO nanoparticles were characterized by studying their structure with X-ray diffraction and composition by energy dispersive X-ray analysis. The size of the nanoparticles is estimated by particle size analyzer and transmission electron microscopy. The optical studies were carried out with Uv-Vis spectrophotometer.
ARR5 and ARR6 Mediate Tissue Specific Cross-talk between Auxin and Cytokinin in Arabidopsis  [PDF]
Aparna Kakani, Zhaohua Peng
American Journal of Plant Sciences (AJPS) , 2011, DOI: 10.4236/ajps.2011.24065
Abstract: Auxin and cytokinin interaction plays an essential role in a wide range of plant growth and developmental processes. The interaction consequence of the two hormones is highly tissue specific. The molecular mechanisms underlying the tissue specificity are largely unknown. Here we show that the cytokinin signaling pathway key components ARR5 and ARR6 respond to auxin with a highly tissue specific and contrasted pattern in Arabidopsis seedlings and calli in the presence of cytokinin. Our results suggest that the two highly homologous but functionally distinct genes, ARR5 and ARR6, play a critical role in mediating tissue specific interaction between auxin and cytokinin.
Keystroke Dynamics Based Authentication Using Information Sets  [PDF]
Aparna Bhatia, Madasu Hanmandlu
Journal of Modern Physics (JMP) , 2017, DOI: 10.4236/jmp.2017.89094
Abstract: This paper presents keystroke dynamics based authentication system using the information set concept. Two types of membership functions (MFs) are computed: one based on the timing features of all the samples and another based on the timing features of a single sample. These MFs lead to two types of information components (spatial and temporal) which are concatenated and modified to produce different feature types. Two Component Information Set (TCIS) is proposed for keystroke dynamics based user authentication. The keystroke features are converted into TCIS features which are then classified by SVM, Random Forest and proposed Convex Entropy Based Hanman Classifier. The TCIS features are capable of representing the spatial and temporal uncertainties. The performance of the proposed features is tested on CMU benchmark dataset in terms of error rates (FAR, FRR, EER) and accuracy of the features. In addition, the proposed features are also tested on Android Touch screen based Mobile Keystroke Dataset. The TCIS features improve the performance and give lower error rates and better accuracy than that of the existing features in literature.
Gap Functions and Error Bounds for Set-Valued Vector Quasi Variational Inequality Problems  [PDF]
Rachana Gupta, Aparna Mehra
Applied Mathematics (AM) , 2017, DOI: 10.4236/am.2017.812135
Abstract:
One of the classical approaches in the analysis of a variational inequality problem is to transform it into an equivalent optimization problem via the notion of gap function. The gap functions are useful tools in deriving the error bounds which provide an estimated distance between a specific point and the exact solution of variational inequality problem. In this paper, we follow a similar approach for set-valued vector quasi variational inequality problems and define the gap functions based on scalarization scheme as well as the one with no scalar parameter. The error bounds results are obtained under fixed point symmetric and locally α-Holder assumptions on the set-valued map describing the domain of solution space of a set-valued vector quasi variational inequality problem.
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