128 research outputs found
Towards Understanding Cytotoxicity And Cellular Uptake Of Engineered Nanomaterials
With a widespread use of nanomaterials in various manufacturing applications including consumer goods, semiconductor industry and pharmaceuticals, the safety of Engineering Nanomaterials (ENs) is a vital area of research. It is extremely important to analyze the risks posed by ENs in order to optimize design and/or control their use. The overarching goal of this work is to understand the cytotoxicity and cellular uptake potential of specific EN of well characterized physicochemical properties. Towards this objective, the specific aims of this project are to (a) comprehensively characterize the physical and chemical properties of starting ENs, (b) study their dose and time-course cytotoxic responses using cell viability assays and (c) assess cellular uptake of nanomaterials in mammalian cell types. Three nanomaterials were studied in this work - gold nanorods, zinc oxide and silica nanoparticles. The mammalian cell types used include 3T3 fibroblasts, neuronal PC12 and Normal Human Bronchial Epithelial (NHBE) cells. The extent of toxicity on these cell lines is studied by first characterizing the ENs using XRD, DLS and SEM analysis to determine physical and chemical properties prior to introduction. Next, cytotoxicity response is acquired using viability assay studies such as MTT and LDH assay. This analysis is further substantiated by using SEM and confocal microscopy to correlate dose-dependent cytotoxicity to morphological changes. Lastly, cellular uptake of the nanomaterials is investigated. Toxicity of nanomaterials is found to increase with concentration and is dependent on the properties of the material and the target species
A VALIDATED GRADIENT STABILITY-INDICATING LC METHOD FOR THE ANALYSIS OF VALSARTAN IN PHARMACEUTICAL DOSAGE FORM
Objective: The objective of this research work was to develop a sensitive, precise, specific, linear and stability-indicating gradient HPLC method for the estimation of valsartan in bulk drug and in pharmaceutical preparations.Methods: Chromatographic separation was achieved on C-18 stationary phase with a gradient mobile phase consisting of orthophosphoric acid buffer (the pH of the solution was adjusted to 4.2±0.05 with triethylamine) and methanol. The eluent was monitored with PDA detector at 225 nm with a flow rate of 1.0 ml/min, run time of 65 min.Results: The method was linear over the range of 20-120μg/ml. The correlation coefficient was found to be 0.9994±0.02. In order to check the selectivity of the method for pharmaceutical preparations, forced degradation studies were carried out. Valsartan was found to be stable at light and oxidation experiments. The performance of the method was validated according to the present ICH guidelines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision and robustness. .The LOQ was found to be 0.26µg/ml and the LOD was found to be 0.79µg/ml. Valsartan showed good correlation coefficient in the concentration range of 20-120μg/ml. The developed method was compared statistically by applying two-way anova and student's t-test to correlate with an isocratic method and was applied to bulk drug and tablet dosage form. There was no significant difference between the two methods.Conclusion: The proposed method was found to be accurate, precise, sensitive and robust. Hence, it can be used successfully for the routine analysis of valsartan in pharmaceutical formulation and for analysis of stability samples obtained during accelerated stability study
Learning Transfer Operators by Kernel Density Estimation
Inference of transfer operators from data is often formulated as a classical
problem that hinges on the Ulam method. The usual description, which we will
call the Ulam-Galerkin method, is in terms of projection onto basis functions
that are characteristic functions supported over a fine grid of rectangles. In
these terms, the usual Ulam-Galerkin approach can be understood as density
estimation by the histogram method. Here we show that the problem can be recast
in statistical density estimation formalism. This recasting of the classical
problem, is a perspective that allows for an explicit and rigorous analysis of
bias and variance, and therefore toward a discussion of the mean square error.
Keywords: Transfer Operators; Frobenius-Perron operator; probability density
estimation; Ulam-Galerkin method;Kernel Density Estimation
Explorations of the Rocky Outcrops of Lower Jira Valley of Bargarh Upland, West Odisha, India
For the last few decades a large number of microlithic sites have been reported in the Jira river valley. All these sites have yielded very rich stone tool antiquities. But these prehistoric lithic assemblages are found in different contexts and geographical locations. A number of open air sites are found in this region which can be categorized into four major types like Foot hill contexts, River Banks, Rocky knobs and Piedmont areas. Prehistoric settlements of all these contexts in this region vary from one to another in use of raw materials and technology. Recent explorations made by author in Jira valley have brought to light some Rocky knob sites in lower part of this valley. In this paper a preliminary study has been made to discuss the cultural antiquity reported from the Rocky Knob sites
Organic receptors for chemical sensors realized on flexible substrates
The aim of this research was to carry out synthesis and characterization of series of dithienyl pyrrole (SNS) based conducting polymers and their applications as chemical gas sensors in the perspective of development of flexible multisensing radio frequency identification (RFID) system for perishable goods monitoring, the aim of the EU project ‘FlexSmell’.
In this context, number of dithienyl pyrrole derivatives were synthesized and polymerized by both chemical and electrochemical methods. The synthesis of SNS based polymers with different functionalities on their backbone was undertaken in order to study the effect of electron donating/withdrawing substituents on the properties of the polymers. The SNS polymers with halogen atoms (F, Cl, Br and I) were also prepared and studied for their effects on the properties of the polymers. Flexible chemoresistive sensors were fabricated by electrochemical deposition of the SNS polymers onto interdigitated electrodes (IDE) substrates. The sensors were characterized against the analytes responsible for decay of perishable goods, such as humidity, ammonia, ethanol etc.
The optical absorption spectra of the SNS conducting polymers showed well defined absorption bands due to π-π* transition or to the transitions among polaron, bipolaron and band states. These features correlate with the good conductivity shown by the investigated compounds when regarded in the frame of the conduction models for organic materials owning delocalised π bonds. The influence of the substituents on the electrical conductivities of the polymers was analysed. The polymers have their electrical conductivity linked to the electron donating character and electronegativity (for the polymers with halogen atoms) of the substituents. The polymers are also studied for their thermal stability, morphology etc. The SNS polymers characterized for their sensing performances against humidity, ammonia and ethanol showed linear increase in their resistances with the relative humidity and a power function one in respect with the concentrations of the other analytes.
Attempts have also been made towards the synthesis of dithienyl pyrrole-dialkylbithiazoles copolymers for the synthesis of easily soluble and environmentally stable polymeric materials intended to be used for chemical sensing.
The main goal of the FlexSmell project, development of flexible multisensing RFID system was achieved by working in collaboration with Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland, The University of Manchester (UK) and Holst Centre (The Netherlands). The multisensor platform was developed at EPFL whereas RFID tag at Holst Centre. Multisensor platforms with sensors of different transduction principles were fabricated by ink-jet printing of Ag-nanoparticle ink on flexible polyethylene terephthalate foils. The platforms have two IDE capacitors for humidity sensing, one resistive temperature detector for temperature measurement and two IDE resistive devices for ammonia and VOCs detection. The capacitive devices were functionalised with cellulose acetate butyrate or polyether urethane layers at University of Tübingen whereas resistive ones with polyaniline and polypyrrole layers at The University of Manchester. The RFID tag was integrated with the multisensor platform through a hybrid approach. In comparison with the currently available RFID sensing systems based on silicon technology, our prototype of low cost flexible multisensing platform with wireless communication capabilities represents a very promising approach for the next generations of smart RFID tags.
Another part of the work explored the possibility to incorporate porcine odorant binding proteins in the structure of field effect gas biosensors through chemical and physical immobilization of the biological material on gold coated substrates. The concept has been tested by differential Kelvin probe measurements. This investigation was also performed in the frame of FlexSmell project for future developments of biosensor based RFID systems.
Keywords: Conducting polymers, Dithienyl pyrrole, Chemical gas sensors, Smart multisensing RFID, Biosensors
Ionic liquids with and without transition metal nanoparticles for advanced heat transfer fluids and catalysis applications.
Tecnologies de transferència de calor de nova generació, amb menys consum d'energia per al benestar de la societat són necessàries. En aquest sentit, els líquids iònics (ILS) són en l'actualitat els fluids més investigats per la seva major estabilitat tèrmica i la naturalesa no volàtil que els fan més avantatjosos que els fluids convencionals. A més, la dispersió de nanopartícules metàl·liques en els fluids convencionals també estan sent investigats en els últims temps a causa de la seva major conductivitat tèrmica, millora en la fluïdesa reduint el cost de bombament, i absència de sedimentació de sal. Aquestes característiques fan fascinants als nanofluidos (NFs) com una bona alternativa a les solucions salines convencionals per a aplicacions de transferència de calor. En aquest treball, ILS basats en el catió imidazoli es van preparar amb anions com ara clorur, bromur, iodur i tetrafluroborate. Diverses propietats termofísiques com la conductivitat tèrmica, capacitat calorífica, densitat i viscositat d'aquests fluids van ser investigades en detall. Com que només hi ha molt pocs treballs publicats sobre NPs de metalls de transició en líquids iònics per a aplicacions de transferència de calor, aquesta tesi s'enfoca en el disseny de les ILS desitjats i en el desenvolupament de materials compostos de metalls de transició NPs amb els ILS iònics preparats. Per a aquest propòsit, es van utilitzar NPs de ruteni (Ru) i plata (Ag). Les propietats tèrmiques d'aquests líquids iònics es van millorar mitjançant la preparació in situ de compostos d'ILS amb nanopartícules de ruteni sense utilitzar agents tensioactius, a temperatura ambient. Per a la preparació dels ionanofluidos (INFs) amb plata, es van utilitzar nanoparículas amb morfologies variables, de 1D, 2D i 3D. Aquests ionanofluids redueixen la viscositat de líquids iònics de base juntament amb la millora en la seva conductivitat tèrmica. Des d'aquesta perspectiva, un catalitzador de carbó amb 5% de ruteni amb àcid de Bronsted IL [Hmim] [HSO4] com un co-catalitzador va ser desenvolupat per hidrogenólisis selectiva del bio-derivat d'àcid levulínic (LA) gamma-valerolactona (GVL) , el qual és un additiu de combustibles.Tecnologías de transferencia de calor de nueva generación, con menos consumo de energía para el bienestar de la sociedad son necesarias. En este sentido, los líquidos iónicos (ILs) son en la actualidad los fluidos más investigados debido a su mayor estabilidad térmica y la naturaleza no volátil que los hacen más ventajosos que los fluidos convencionales. Además, la dispersión de nanopartículas metálicas en los fluidos convencionales también están siendo investigados en los últimos tiempos debido a su mayor conductividad térmica, mejora en la fluidez reduciendo el coste de bombeo, y ausencia de sedimentación de sal. Estas características hacen fascinantes a los nanofluidos (NFs) como una buena alternativa a las soluciones salinas convencionales para aplicaciones de transferencia de calor. En este trabajo, ILs basados en el catión imidazolio se prepararon con aniones tales como cloruro, bromuro, yoduro y tetrafluroborate. Varias propiedades termofísicas como la conductividad térmica, capacidad calorífica, densidad y viscosidad de estos fluidos fueron investigadas en detalle. Como sólo hay muy pocos trabajos publicados sobre NPs de metales de transición en líquidos iónicos para aplicaciones de transferencia de calor, esta tesis se enfoca en el diseño de las ILs deseados y en el desarrollo de materiales compuestos de metales de transición NPs con los ILs iónicos preparados. Para este propósito, se utilizaron NPs de rutenio (Ru) y plata (Ag). Las propiedades térmicas de estos líquidos iónicos se mejoraron mediante la preparación in situ de compuestos de ILs con nanopartículas de rutenio sin utilizar agentes tensioactivos, a temperatura ambiente. Para la preparación de los ionanofluidos (INFs) con plata, se utilizaron nanoparículas con morfologías variables, de 1D, 2D y 3D. Estos ionanofluids reducen la viscosidad de líquidos iónicos de base junto con la mejora en su conductividad térmica. Desde esta perspectiva, un catalizador de carbon con 5% de rutenio con ácido de Bronsted IL [Hmim] [HSO4] como un co-catalizador fue desarrollado para hidrogenólisis selectiva del bio-derivado de ácido levulínico (LA) gamma-valerolactona (GVL), el cual es un aditivo de combustibles.New generation heat transfer technologies with less energy consumption and improved economy are needed for welfare of the society. In this regard, ionic liquids (ILs) are most investigated fluids due to their higher thermal stability and non-volatile nature which make them more advantageous than the conventional fluids. In addition, dispersion of metal nanoparticles in conventional fluids are also being investigated in recent times due to their higher thermal conductivity, easy flow, which reduce pumping cost as well as no salt sedimentation. These fascinating features make NFs as a good alternative to the conventional salt solutions for heat transfer applications. In this work, imidazolium cation based ILs were prepared with variation in anions such as chloride, bromide, iodide and tetrafluroborate. Several thermophysical properties as thermal conductivity, heat capacity, density and viscosity of these fluids were investigated in detail. As there are only a very few reports available on transition metal NPs in ILs for heat transfer applications, this thesis work is focused on first designing the desired ILs and then developing composites of transition metal NPs with the prepared ionic ILs. For this purpose, NPs of ruthenium (Ru) and silver (Ag) were used. Thermal properties of these ILs were improved by in-situ preparation of composites of ILs with ruthenium nanoparticles without using capping agents or surfactants at room temperature. For preparing Ag containing ionanofluids (INFs), readily available NPs of Ag with variable morphologies, of 1D, 2 D and 3 D were used. These ionanofluids reduced the viscosity of base ILs along with the enhancement in their thermal conductivity. From this perspective, Carbon supported 5% ruthenium catalyst with Bronsted acidic IL [Hmim][HSO4] as a co-catalyst was developed for selective hydrogenolysis of bio-derived levulinic acid (LA) gamma-valerolactone (GVL) which is fuel additive
SYNTHESIS, CHARACTERIZATION AND ANTIOXIDANT ACTIVITY OF POTASSIUM CIS-DIAQUA-BIS (OXALATO) CHROMATE (III) WITH LEVODOPA AND CARBIDOPA
Objective: These studies focus on the interaction between two clinically active antiparkinsonian drugs L-dopa (L) and carbidopa (C) with the cis-[Cr(C2O4)2(H2O)2]-and evaluation of the synthesized product from a coordination chemistry aspect with respect to the possibility of its antioxidant activity and its therapeutic application in the treatment of Parkinson disease.Methods: The resulting synthesized complexes were characterized by UV-VIS and FTIR spectroscopy. Evaluation of antioxidant activities of this cis-[Cr(C2O4)2(H2O)2]--L-dopa(ML), cis-[Cr(C2O4)2(H2O)2]--carbidopa(MC) and standard butylated hydroxytoluene (BHT) were carried out by using 1,1-diphenyl-1-picrylhydrazyl free radical (DPPH), 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cations and hydrogen peroxide method.Results: The results of spectral analysis of the synthesized products indicate that complexes have a Cr(III) ion coordinated via the carboxylic and amino group. In the reduction of radical DPPH· and the formation of radical monocation ABTS·+the ability to scavenge radical was measured in these experiments by the discoloration of the solution. However, in hydrogen peroxide method, the increased in absorbance showing its scavenging potential. The scavenging capacity of the test compounds and standard on the DPPH, ABTS·+, H2O2 decreased in the order BHT>ML>MC>C>L which were 98.4, 96.4, 86.4, 68.3, 49.7% for DPPH, BHT>ML>L>MC>C which were 99.3, 96.9, 96.3,66.6, 53.4% for ABTS·+, BHT>ML>MC>L>C which were 68.8%, 52.4%, 49.6%, 43.1% and 37.7% for H2O2 at the concentration of 50 µg/ml, respectively.Conclusion: The experimental findings showed that cis-[Cr(C2O4)2(H2O)2]--levodopa and cis-[Cr(C2O4)2(H2O)2]--carbidopa are having higher antioxidant potential than Levodopa and carbidopa although not superior to that of standard compound
DOCUMENTATION OF TRIBAL CLAIMS FOR RHEUMATISM IN ODISHA, INDIA
Objectives: Odisha has been known as a rich source of valuable medicinal plants. Present work enumerates the indigenous knowledge on plant utilized as a natural remedy for rheumatism by the local or native peoples of Odisha.Methods: Information on curative values of different wild drug plant species has been gathered through personal interaction with tribal peoples. The study was conducted during the year 2010-2011 following standard ethno botanical methods.Results: A total of 144 plant species belonging to 57 families and 130 genera has been documented. The dominant families are Fabaceae, Acacthaceae, Apocyaceae, Euphorbiaceae, Malvaceae. Shrubs (34%) were the primary source of medicine, followed by herbs (32%) and trees (22%). High rate of frequency citation (Fc) of different medicinal plant species reveals that the current ethno botanical claims are strongly authenticated and needs to be further phytochemical and pharmacological investigation of herbal drug development program.Conclusions: Immediate steps should be taken not only to protect the medicinal flora of the state, but also to conserve the valuable traditional knowledge prior to extinction.Â
Invasive Alien Flora in and around an Urban Area of India
Invasive alien species are non-native exotic organisms which can disperse and destroy the biodiversity and change the ecosystem. The present study deals with the comprehensive list of invasive alien plants (IAPs) of Rourkela Steel City, Sundargarh, Odisha, with background information on family, habit, and nativity. A total of 165 invasive alien species under 132 genera and 59 families have been recorded. From the nativity study, among 25 geographic regions, the majority of invasive plants reported from American continent (62%) with 103 species. While in life form analysis, the herbs (114 species) are dominant, followed by trees (23 species), shrubs (22 species), climber (5 species), and undershrub (1 species). Ageratum conyzoides, Blumea lacera, Cassia alata, Lantana camara, Cassia tora, Parthenium hysterophorus, Xanthium sp., Datura sp., Cardamine scutata, Argemone mexicana, Grangea maderaspatana, Hyptis suaveolens, and Gnaphalium polycaulon are some noxious species found during the study. Parthenium hysterophorus is the highly noxious plant which is grown everywhere after Ageratum conyzoides and Lantana camara. Most of the invasive species are locally used for medicinal purposes as well as for food, fuel, and fodder purposes. A better planning and reporting of the spread of new plants in the area are needed for early identification and control of the invasive alien plant species in different seasons. Since the flora of Sundargarh districts has not been beneficially explored, this study will help in the compilation of flora of Sundargarh district and Rourkela in particular. Further studies will reveal the allelopathic effects on different agricultural crops as well as the different ethnobotanical values
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