Informatics Publishing Limited

K. Shailaja ¹, R. Revathi ¹, V. S. Saravanan ¹

Affiliations
1 Department of Pharmaceutical Analysis, The Erode College of Pharmacy and Research, Erode- 638112, IN

Abstract

A simple, accurate and precise reverse phase high performance liquid chromatographic (RP-HPLC) method was developed for the simultaneous quantitative estimation of Emtricitabine (EMT) and Tenofovir disoproxil fumerate (TDF) in tablet dosage form. Quantitation was carried on an ACE (150 mm x 4.6mm, 5μ) column using gradient composition of 0.01 M citric acid monohydrate buffer pH 4.5 as mobile phase A and methanol as mobile phase B at a flow rate of 1.0 mL/min with detection at 260 nm. Determination of the different validation parameters such as precision, linearity, accuracy, specificity, robustness, limit of detection, limit of quantification and filter validation was done. The system suitability parameters such as retention time, theoretical plates and tailing factor were found to be 3.181min, 13438, 0.14 and 6.090min, 48847, 1.05 respectively for EMT and TDF. The detector response is linear from 16 μg/mL to 64 μg/mL for EMT and 24 μg/mL to 96 μg/mL TDF. The limit of detection and limit of quantification was 0.101, 0.189 μg/mLand 0.306, 0.575 μg/mL for EMT and TDF respectively. The percentage recovery for average of three different concentrations (50, 100 and 150%) was 101.1, 100.6, 99.8 and 99.7, 99.4, 99.6% for EMT and TDF respectively.The high percentage of recovery and low % RSD confirms the suitability of the method for the simultaneous estimation of EMT and TDF in tablet dosage form.The method could effectively separate the drugs from their degradation products, it can be regarded as stability indicating method.

Keywords

RP-HPLC, Simultaneous Estimation, EMT, TDF, Forced Degradation Studies

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C. Nandha Kumar ¹, R. Revathi ¹, I. Jaisankar ¹, K. Baranidharan ¹, P. Durai Rasu ¹

Affiliations
1 Forest College and Research Institute, Mettupalayam, Tamilnadu- 641 301, IN

Abstract

Birds are excellent indicators of water quality and measures of biodiversity. The study on bird diversity was conducted during November 2012 to March 2013 at Ukkadam Lake, Coimbatore, Tamil Nadu. Total of 48 avifaunal species belonging to 20 families were recorded in the study area. The result showed that only one species was rare, one species was winter visitor, two species belong to nearly threatened category, two species critically endangered and forty species were under the least concerned category. Species diversity and species richness showed that more bird diversity occurred in the month of March followed by January and February and least in the month of November. Highest bird population was observed in the monthJanuary and February

Keywords

Wetland, Bird Diversity, Tamilnadu, Conservation, Avifaunal Diversity

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R. Revathi ¹, R. Rajeswari ¹

Affiliations
1 Department of Mathematics, Sathyabama University, Chennai 600119, IN

Abstract

A graph G (V,E) with |V| = n is said to have modular multiplicative divisor labeling if there exist a bijection f: V(G) → {1, 2, …,} and the induced function f^*: E(G) → {0, 1, 2, …, n - 1} where f(uv) = f(u)f(v) (mod n) such that n divides the sum of all edge labels of G. We prove that the path P_n , and the graph P_{a, b} (a graph which connects two vertices by means of "b" internally disjoint paths of length "a" each), shadow graph of a path and the cartesian product P_n × P₁, (n is not a multiple of 6) admits modular multiplicative divisor labeling. Also we discuss the upper bound for the number of edges in a modular multiplicative divisor graphs. AMS Subject Classification: 05C78

Keywords

Graph Labeling, Path, Graph P_a,b, Shadow Graph D₂(G), the Cartesian Product P_n × P₁

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S. John Peter ¹, R. Revathi ¹, I. Jaisankar ¹, P. Durai Rasu ¹

Affiliations
1 Forest College and Research Institute, Mettupalayam, Tamilnadu, IN

Abstract

A total of 87 bird species belonging to 13 orders and 31 families of terrestrial and semi-aquatic birds were identified and recorded during the study. The highest population of bird species recorded during the month of January followed by December. The maximum number of birds was observed of the corvidae family (11 species) followed by columbidae (6 species) and passeridae (6 species). The highest diversity of 4.19 was observed in the month of January followed by 4.17 in the month of February and 4.15 in the month of April. Species richness was highest in the month of January followed by February and least in April. This study illustrated useful information on bird diversity in the study region which serves as a baseline for future monitoring programs.

Keywords

Birds Diversity, Species Richness, Nilgiris, Bird Community.

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R. Revathi ¹, Mohan Kumar ²

Affiliations
1 Department of Information and Communication Engineering, S.K.P Engineering College, Tiruvannamalai-606611, IN
2 Information and Communication Engineering, SKP Engineering College, Tiruvannamalai, Tamil Nadu, IN

Abstract

This paper presents Circuit level model of a dual gate bilayer and four layers GFET. This model accurately estimates the conductance at the charge neutrality point (CNP). At the CNP, the device has its maximum resistance, (i) Validates the device off-current for a range of Electric field perpendicular to channel (ii) Estimates the amount of bandgap opening created by application of Electric field using the general Schottky equation. (iii) Validates the channel output conductance against varying gate voltage for both a bilayer and four layer graphene channels.

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R. Revathi ¹, Mohan Kumar ²

Affiliations
1 Department of Information and Communication Engineering, S.K.P. Engineering College, Tiruvannamalai-606611, IN
2 Information and Communication Engineering, SKP Engineering College, Tiruvannamalai, IN

Abstract

This paper presents Circuit level model of a dual gate bilayer and four layers GFET. This model accurately estimates the conductance at the charge neutrality point (CNP). At the CNP, the device has its maximum resistance, (i) Validates the device off-current for a range of Electric field perpendicular to channel (ii) Estimates the amount of bandgap opening created by application of Electric field using the general Schottky equation. (iii) Validates the channel output conductance against varying gate voltage for both a bilayer and four layer graphene channels.

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S. K. Baji ¹, K. S. Ramesh ¹, R. Revathi ¹, S. Koteswara Rao ¹

Affiliations
1 K L University, Green fields, Vaddeswaram - 522502, Andhra Pradesh, IN

Abstract

Background/Objectives: Earthquakes are the more vulnerable disasters for mankind and are inevitable. The major objective of our work is to identify the precursors of earthquakes and analysed the precursors in ionosphere prior to the occurrence of earthquake using Global Positioning System Total Electronic Content (GPSTEC). Methods/Statistical Analysis: In this work Multiple Signal Classification algorithm (MUSIC) is explored. MUSIC estimates the frequency content of a signal or autocorrelation matrix using a Eigen space method. Findings: It is clearly observed that there is a significant raise in energy of the ionosphere on the day of earthquake occurrence. Application/Improvement: If the quality data is available before and after the occurrence of earthquake also, then it may be possible to develop the early warning system for earthquakes.

Keywords

Earthquakes, GPSTEC, Ionosphere, Multiple Signal Classification (MUSIC), Seismo-ionospheric Perturbations.

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A. V. V. Pavani ¹, D. Tejasri ¹, R. Revathi ¹, K. S. Ramesh ¹, S. Koteswara Rao ¹, S. Lakshminarayana ¹

Affiliations
1 Guntur, Andhra Pradesh, IN

Abstract

Background/Objectives: Ionospheric total electron content perturbations generated by earthquake occurred in Indonesia are analyzed. Methods/Statistical Analysis: The vertical total electron content data on the earthquake day is detrended such that it can be analyzed using statistical signal processing algorithms. Modified periodogram algorithm is implemented on both the disturbed and undisturbed vertical total electron content data. Findings: From the power spectral densities of modified periodogram, the time of occurrence of earthquake is observed and it is noted that it is matching with the actual time of occurrence of event considered. Application/Improvement: This analysis aids in developing an early warning system for earthquakes.

Keywords

Atmospheric Sciences, Earthquakes, Global Positioning System, Statistical Signal Processing.

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Ch. Goutham ¹, K. Rakesh ¹, K. S. Ramesh ¹, R. Revathi ¹, S. Koteswra Rao ¹, P. Chitra ¹, V. N. Ramakrishnan ¹

Affiliations
1 Guntur, Andhra Pradesh, IN

Abstract

Background/Objectives: Earthquakes are the most unpredictable natural disasters in nature. Spectral analysis of seismoionospheric perturbations will be helpful in understanding the source mechanisms of the earthquakes. Seismogenic perturbations observed in ionosphere for an earthquake occurred on 19th December 2013 are investigated. The earthquake peaked at 4.6 on Richter scale. It took place at 16:41 hour's green which mean time. International global navigation satellite services data for the station BAKO is considered for the analysis. Methods/Statistical Analysis: In present work Bartlett method is implemented on the vertical total electron content data on the earthquake day. Findings: Earthquake signatures in the ionosphere are indentified. It is also observed that the power spectral density of the perturbations has a giant initial value and abated slowly. Application: These findings will aid us to develop early warning systems for earthquakes.

Keywords

Earthquake, Signal Processing, Upper Atmospheric Sciences.

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R. Revathi ¹, V. S. Saravanan ¹, T. Ethiraj ², Jhansi Lakshmi Marreddy ¹

Affiliations
1 Department of Pharmaceutical Analysis, The Erode College of Pharmacy and Research, Erode, Tamil Nadu, IN
2 Department of Pharmaceutics, The Erode College of Pharmacy and Research, Erode, Tamil Nadu, IN

Abstract

A simple reverse phase liquid chromatographic method was developed and validated as per the ICH guidelines for the quantitative determination of candesartan cilexetil in pharmaceutical dosage forms. The mobile phase consisted of 0.02 M mono basic potassium phosphate buffer: acetonitrile: triethyl amine (40:60:0.2) and adjust pH to 6.0 with ortho phosphoric acid. The eluent was monitored at 254 nm, at a flow rate of 2 mL/min and retention time was observed at 9.153 min. The linearity was observed from 0.08071-0.24213 mg/mL with R2= 0.998. The LOD and LOQ were found to be 0.00005 mg/mL and 0.00017 mg/mL respectively. This method was also validated and can be successfully applied for routine analysis.

Keywords

Candesartan Cilexetil, RP-HPLC, Validation.

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R. Revathi ¹, P. Venkata Naga Suresh ¹, M. Koteswara Rao ¹, T. Ethiraj ², S. Rajarajan ³

Affiliations
1 Dept. of Pharmaceutical Analysis, The Erode College of Pharmacy and Research, Erode-638112, Tamil Nadu, IN
2 Dept. of Pharmaceutics, The Erode College of Pharmacy and Research, Erode-638112, Tamil Nadu, IN
3 Dept. of Pharmacy Practice, The Erode College of Pharmacy and Research, Erode-638112, Tamil Nadu, IN

Abstract

Objective of the present work is to optimize condition to develop UV zero order, first derivative spectrophotometric method and a simple, rapid and reproducible RP-HPLC method for the estimation of didanosine in selected dosage form. Chromatographic separation of didanosine was achieved with chromosil column (150 mm x 4.6 mm i.d, 5μ particle size), mobile phase used was phosphate buffer: acetonitrile: methanol in the ratio of 20:35:45 with 0.6 ml/min flow rate. The chromatograms were recorded at 248nm.The retention time was < 3 minutes (2.72±0.1). The method was validated for system suitability, precision, accuracy, linearity and robustness. The isocratic LC method offers simplicity, selectivity, precision, accuracy and less time consuming. Hence these two methods can be used for the routine analysis of the estimation of didanosine in Pharmaceutical dosage form.

Keywords

Didanosine, Accuracy, Linearity, Retention Time.

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R. Revathi ¹

Affiliations
1 Department of Computer Science, Jawaharlal Nehru College for Women, Ulundurpet, IN

Abstract

A common goal of the engineering field of signal processing is to reconstruct a signal from a series of sampling measurements. In general, this task is impossible because there is no way to reconstruct a signal during the times that the signal is not measured. Nevertheless, with prior knowledge or assumptions about the signal, it turns out to be possible to perfectly reconstruct a signal from a series of measurements. Over time, engineers have improved their understanding of which assumptions are practical and how they can be generalized. An early breakthrough in signal processing was the Nyquist-Shannon sampling theorem. It states that if the signal's highest frequency is less than half of the sampling rate, then the signal can be reconstructed perfectly. The main idea is that with prior knowledge about constraints on the signal's frequencies, fewer samples are needed to reconstruct the signal. Sparse sampling (also known as, compressive sampling, or compressed sampling) is a signal processing technique for efficiently acquiring and reconstructing a signal, by finding solutions to underdetermined linear systems. This is based on the principle that, through optimization, the sparsity of a signal can be exploited to recover it from far fewer samples than required by the Shannon-Nyquist sampling theorem. There are two conditions under which recovery is possible.[1] The first one is sparsity which requires the signal to be sparse in some domain. The second one is incoherence which is applied through the isometric property which is sufficient for sparse signals Possibility of compressed data acquisition protocols which directly acquire just the important information Sparse sampling (CS) is a fast growing area of research. It neglects the extravagant acquisition process by measuring lesser values to reconstruct the image or signal. Sparse sampling is adopted successfully in various fields of image processing and proved its efficiency. Some of the image processing applications like face recognition, video encoding, Image encryption and reconstruction are presented here.

Keywords

Sparse Sampling, Image Enhancement, Top-Hat and Bottom-Hat Transform, Nyquist Rate, AFM Imaging.

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R. Revathi ¹

Affiliations
1 Department of Computer Science, Jawaharlal Nehru College for Women, Ulundurpet, IN

Abstract

Image denoising is an important image processing task, both as a process itself, and as a component in other processes. Very many ways to denoise an image or a set of data exists. The main properties of a good image denoising model are that it will remove noise while preserving edges. Traditionally, linear models have been used. One common approach is to use a Gaussian filter, or equivalently solving the heat-equation with the noisy image as input-data, i.e. a linear, 2nd order PDE-model. For some purposes this kind of denoising is adequate. One big advantage of linear noise removal models is the speed. But a back draw of the linear models is that they are not able to preserve edges in a good manner: edges, which are recognized as discontinuities in the image, are smeared out. Here I am using a novel approach to image denoising that is level set approach is employed. Level Set Methods offer an appealing approach to noise removal. In particular, they exploit the fact that curves moving under their curvature smooth out and disappear. Since the method evolves contours, boundaries remain essentially sharp and do not blur. Second, a "min/max" switch is used to control whether or not curvature flow is applied; this results in an algorithm that stops automatically once the smallest features are removed.

Keywords

Gaussian Denoising, Single Image Super-Resolution (SISR) and JPEG Image Deblocking, DnCNN, AWGN.

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