bluuebunny/crossref_metadata_2025 huggingface dataset:
DIAMETER VULNERABILITY OF DIRECTED CYCLES AND DIRECTED TORI
Authors: MA XIAOYAN , HUANG XIAOHUI , ZHANG ZHAO
Published: April 2012

The diameter of a graph is important for the network as it measures the maximum communication delay between any pair of processors. In this paper, we study the diameter vulnerability of the directed cycle [Formula: see text] and the directed torus [Formula: see text] with respect to arc addition, that is, what is the minimum number of arcs the addition of which reduces the diameter by at least k.
Analytical inference model for prediction and customization of inter-agent dependency requirements
Authors: Gaur Vibha , Soni Anuja
Published: April 2012

Inter-agent communication is one of the main concerns of Agent Oriented Requirements Engineering (AORE). The concern is delineated as managing inter-dependencies and interaction among various agents performing collaborative activities. To carry out cooperative activities, the application areas viz. electronic commerce and enterprise resource planning in the distributed environment require an agent to predict and customize dependency needs termed as Degree of Dependency (DoD) so that the goal may be obtained within resource constraints and with optimal number of agents. To quantify and predict exertion load of an agent within resource constraints, this paper proposes an Analytical Inference Model (AIM) that would facilitate the developer to evaluate and envisage DoD and hence analyze the optimum number of agents to obtain predicted DoD. In this work, Adaptive Neuro Fuzzy Inference System (ANFIS) combining the potential benefits of Artificial Neural Network (ANN) and Fuzzy Logic (FL) is employed to discover the linear relationship in input domain attributes and DoD. The resultant optimization of exertion loads would immensely improve the quality of the Multi-Agent System. The hybrid, as well as back propagation learning algorithm, is employed to adapt from training data. The bestfitness of proposed model against test data is examined by the performance indicators-Coefficient of Correlation (CORR) and the Normalized Root Mean Square Error (NRMSE). It is observed that hybrid learning algorithm outperforms the back propagation algorithm.
The role of CaMKII in regulating GLUT4 expression in skeletal muscle
Authors: Ojuka Edward O. , Goyaram Veeraj , Smith James A. H.
Published: April 2012

Contractile activity during physical exercise induces an increase in GLUT4 expression in skeletal muscle, helping to improve glucose transport capacity and insulin sensitivity. An important mechanism by which exercise upregulates GLUT4 is through the activation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) in response to elevated levels of cytosolic Ca2+during muscle contraction. This review discusses the mechanism by which Ca2+activates CaMKII, explains research techniques currently used to alter CaMK activity in cells, and highlights various exercise models and pharmacological agents that have been used to provide evidence that CaMKII plays an important role in regulating GLUT4 expression. With regard to transcriptional mechanisms, the key research studies that identified myocyte enhancer factor 2 (MEF2) and GLUT4 enhancer factor as the major transcription factors regulating glut4 gene expression, together with their binding domains, are underlined. Experimental evidence showing that CaMK activation induces hyperacetylation of histones in the vicinity of the MEF2 domain and increases MEF2 binding to its cis element to influence MEF2-dependent Glut4 gene expression are also given along with data suggesting that p300 might be involved in acetylating histones on the Glut4 gene. Finally, an appraisal of the roles of other calcium- and non-calcium-dependent mechanisms, including the major HDAC kinases in GLUT4 expression, is also given.
Recovery of Copper, Nickel and Zinc from Sulfate Solutions by Solvent Extraction Using LIX 984N
Authors: Sridhar Vaishnavi , Verma J. K.
Published: April 2012

Recovery of valuable metals such as copper, nickel and zinc from synthetic sulfate solutions using LIX 984N as the extractant dissolved in kerosene was investigated. The metals get extracted at different equilibrium pH of the aqueous phase and thus the pH of the aqueous solutions forms the basis of their separation. Copper was extracted at an equilibrium pH of 3.5, while nickel and zinc get extracted at an equilibrium pH of 7.3 and 8.8 respectively. The extraction isotherms of copper, nickel and zinc were obtained by contacting the respective metal solutions and 0.05 M LIX 984N at different A:O phase ratio at their respective equilibrium pH of maximum extraction. A two‐stage counter‐ current extraction simulation was done to achieve quantitative extraction of the metals. Furthermore, a two‐stage counter‐ current stripping simulation yielded quantitative recovery of the individual metals, from their loaded organic phases. On the basis of the results, a flow sheet of the process has been developed.
Thermal Properties of Some Organic Liquids Using Ultrasonic Velocity Measurements
Authors: Ramadoss P. , Buvaneswari N.
Published: April 2012

Debye temperature and thermal relaxation time has been calculated in normal and boiling temperature. Using thermal relaxation time, the heat of fusion has been calculated for nineteen organic liquids and the results throw light on the method of calculating heat of fusion.
Formation of the River Water Chemistry in the Middle Section of Dousitu River, China
Authors: Hui Qian , Peiyue Li , Jia Ding , Chao Yang , Xuedi Zhang
Published: April 2012

On basis of hydrogeology of the study area, the characteristics of chemistry of river water and groundwater were analyzed. Analysis results of three river water samples (B3, B4 and B5) collected in the middle section of Dousitu River show the TDS increases from B3 to B4 and decreases from B4 to B5. The concentrations of Cl-, Na+, K+, Mg2+ and HCO3- have a similar change with TDS, but the concentrations of Ca2+ and SO42- increase steadily along flow path. The chemical types of the river water change from HCO3•Cl‐Na to Cl•SO4•HCO3‐Na and finally to SO4•Cl‐Na. The causes of these changes are analyzed and studied in depth using various methods. Results indicate river water evaporation, dissolution/precipitation of minerals, cation exchange and mixing of different waters all play important roles in the formation of the river water chemistry. But in different sections of the river, the main processes are different. The study shows that when a reservoir is built in arid areas, the loss of water resources due to evaporation is huge, which can lead to the degradation of water qualities. Hence, great care should be taken to build a reservoir in arid or semi‐arid regions.
PVC‐Membrane Potentiometric Electrochemical Sensor Based on 2‐(4‐Oxopentan‐2‐ylideneamino)isoindoline‐1,3‐dione for Selective Determination of Holmium(III)
Authors: Zamani Hassan Ali
Published: April 2012

2‐(4‐Oxopentan‐2‐ylideneamino) isoindoline‐1,3‐dione (OID) was found to be a suitable neutral ionophore in the fabrication of a highly selective Ho3+ membrane sensor. The electrode has a near‐Nernstian slope of 19.6±0.5 mV per decade with a wide concentration range between 1.0×10-6 and 1.0×10-2 mol/L in the pH range of 3.5–8.8, having a fast response time (∼5 s) and a detection limit of 5.8×10-7 mol/L. This electrode presented very good selectivity and sensitivity towards the Ho3+ ions over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The practical utility of the electrode has been demonstrated by its use as an indicator electrode for the potentiometric titration of a Ho3+ solution with EDTA and for the determination of Ho3+ ions concentration in mixtures of two and three different ions.
Microwave Induced Improved Synthesis of Some Novel Substituted 1, 3‐Diarylpropenones and their Antimicrobial Activity
Authors: Ameta K. L. , Kumar Biresh , Rathore Nitu S.
Published: April 2012

Application of solid support, solvent free reaction condition and a dynamic microwave power system in the chemical synthesis of some novel 1, 3‐diaryl‐propenones has been described. A series of chalcones (3a-h) were synthesized by the condensation of 4‐hydroxy‐3,5‐dinitroacetophenone with various substituted aromatic aldehydes in presence of montmorrilonite K10 as a catalyst and solid support media under microwave irradiation. The protocol offers several advantages such as simple procedure, fast reaction rate, mild reaction condition, eco‐friendly and improved yield as compared to conventional methods. These compounds have been screened for their antibacterial and antifungal activities against different microorganisms. The structures of novel synthesized compounds have been established on the basis of elemental analysis, 1H NMR, 13C NMR and IR spectral data.
Reactive Extraction of L (+) Tartaric Acid by Amberlite LA‐2 in Different Solvents
Authors: İnci İ. , Aşçi Y. S. , Tuyun A. F.
Published: April 2012

The extraction of L(+) tartaric acid from aqueous solutions by amberlite LA‐2 is a secondary amine mixture in different diluent solvents. Extraction equilibria of L(+) tartaric acid by amberlite LA‐2 in 1‐octanol, cyclohexane, isooctane, hexane, methyl isobutyl ketone (MIBK) solvents at temperature 298.15 K have been measured. The batch extraction experiments distribution coefficients (D), loading factors ( Z) and extraction efficiency (E) were calculated. The maximum removal of L(+) tartaric acid is 91 % with MIBK and 0.92 mol.L-1 initial concentration of Amberlite LA‐2.
Kinetics of Oxidation of 3‐Benzoylpropionic Acid by N‐Bromoacetamide in Aqueous Acetic Acid Medium
Authors: Farook N. A. Mohamed , Seyed Dameem G. A.
Published: April 2012

The kinetics of oxidation of 3‐benzoylpropionic acid (KA) with N‐bromoacetamide (NBA) have been studied potentiometrically in 50:50 (v/v) aqueous acetic acid medium at 298 K The reaction was first order each with respect to [KA], [NBA] and [H+]. The main product of the oxidation is the corresponding carboxylic acid. The rate decreases with the addition of acetamide, one of the products of the reaction. Variation in ionic strength of the reaction medium has no significant effect on the rate of oxidation. But the rate of the reaction is enhanced by lowering the dielectric constant of the reaction medium. A mechanism consistent with observed results have been proposed and the related rate law was deduced.
Zeolite (ZSM‐5) as a Highly Efficient and Heterogeneous Catalyst for the Synthesis of β‐Enaminones and β‐Enamino Esters
Authors: Shekhar Amiya , Pathak Devendra Deo
Published: April 2012

Several β‐enaminones and β‐enaminoesters have been synthesized in high yields from amine and β‐diketone in the presence of Zeolite (ZSM‐5) as a catalyst. This method is applicable to both cyclic and acyclic ketones with aromatic and aliphatic amines.
Removal of Erichrome Black T from Synthetic Wastewater by Cotton Waste
Authors: Ladhe U. V. , K. Wankhede S. , T. Patil V. , R. Patil P.
Published: April 2012

Adsorptions of Erichrome Black T dye in aqueous solution on cotton stem activated carbon have been studied as a function of contact time, concentration and pH. Effect of various experimental parameters has been investigated at 39±1 °C under batch adsorption technique. The result shows that cotton stem activated carbon adsorbs dye to a sufficient extent. The physicochemical characterization and chemical kinetics was also examined for the same dye. The overall result shows that it can be fruitfully used for the removal of dye from wastewaters.
Cloud Point Extraction and Determination of Silver Ion in Real Sample using Bis((1H‐benzo[d ]imidazol‐2yl)methyl)sulfane
Authors: Ahmadi Farshid , Niknam Khodabakhsh , Niknam Ebrahim , Delavari Saeid , Khanmohammadi Azadeh
Published: April 2012

Bis((1H‐benzo[d]imidazol‐2yl)methyl)sulfane (BHIS) was used as a complexing agent in cloud point extraction for the first time and applied for selective pre‐concentration of trace amounts of silver. The method is based on the extraction of silver at pH 8.0 by using non‐ionic surfactant T‐X114 and bis((1H‐benzo[d]imidazol‐2yl)methyl)sulfane as a chelating agent. The adopted concentrations for BHIS, Triton X‐114 and HNO3, bath temperature, centrifuge rate and time were optimized. Detection limits (3SDb/m) of 1.7 along with enrichment factor of 39 for silver ion was achieved. The high efficiency of cloud point extraction to carry out the determination of analytes in complex matrices was demonstrated. The proposed method was successfully applied to the ultra‐trace determination of silver in real samples.
Equilibrium Isotherm Modeling, Kinetics and Thermodynamics Study for Removal of Lead from Waste Water
Authors: Chowdhury Z. , Zain S. M. , Rashid A. K.
Published: April 2012

The low cost adsorbent palm oil fuel ash (POFA) derived from an agricultural waste material was investigated as a replacement of current expensive methods for treating wastewater contaminated by Pb(II) cation. Adsorption studies were carried out to delineate the effect of contact time, temperature, pH and initial metal ion concentration. The experimental data followed pseudo second order kinetics which confirms chemisorptions. The values of Langmuir dimensionless constant, RL and Freundlich constant, 1/n were less than 1 representing favorable process for adsorption. Thermodynamic parameters such as ΔG°, ΔH° and ΔS°, related to Gibbs free energy, enthalpy and entropy were evaluated. It was concluded that, chemically treated palm oil fuel ash (POFA) can be used successfully for adsorption of Pb(II) from aqueous solution.
Adsorption of Malachite Green Dye by Acid Activated Carbon ‐ Kinetic, Thermodynamic and Equilibrium Studies
Authors: Baskaran P. K. , Venkatraman B. R. , Arivoli S.
Published: April 2012

The ability of zea mays dust carbon to remove malachite green from aqueous solutions has been studied for different adsorbate concentrations by varying the amount of adsorbent, temperature, pH and shaking time. Thermodynamic parameters such as ΔH°,ΔS° and ΔG°, were calculated from the slope and intercept of the linear plots. Analysis of adsorption results obtained at 303, 313, 323 and 333 K showed that the adsorption pattern on zea mays dust carbon seems to follow the Langmuir and Freundlich. The numerical values of sorption free energy indicate physical adsorption. The kinetic data indicated an intra‐particle diffusion process with sorption being first order. The concentration of malachite green oxalate was measured before and after adsorption by using UV‐visible spectrophotometer.
Synthesis, Isolation and Characterization of Process‐Related Impurities in Salbutamol Sulphate
Authors: Sharma Yogesh Kumar , Agarwal Dau Dayal , Bhure Sudesh , Mukharjee Rajendra Nath , Sahu Pramod Kumar , Bhardwaj Santosh
Published: April 2012

Three known and one unknown impurities in salbutamol sulphate bulk drug at level 0.1% (ranging from 0.05‐0.1%) were detected by gradient reverse phase high performance liquid chromatography. These impurities were preliminarily identified by the mass number of the impurities. Different experiments were conducted and finally synthesized and characterized the known and unknown imputities.
Stability‐Indicating RP‐HPLC Method for Assay of Silver Lactate
Authors: Srinivasan V. , Sivaramakrishnan H. , Karthikeyan B.
Published: April 2012

A simple, economic and time‐efficient stability‐indicating, reverse‐phase high‐performance liquid chromatographic (RP‐HPLC) method has been developed for analysis of silver lactate in the presence of degradation products generated by decomposition. When silver lactate was subjected to acid hydrolysis, base hydrolysis, oxidative, photolytic, humidity and thermal stress, degradation was observed during base hydrolysis, oxidation, humidity and thermal stress. The drug was found to be stable to other stress conditions. Successful chromatographic condition of the drug from the degradation products formed under stress conditions was achieved on a phenomenex Gemini column with potassium dihydrogen phosphate buffer, pH adjusted to 2.2 with orthophosphoric acid, as mobile phase. The method was validated for linearity, precision, specificity and robustness and can be used for quality‐control during manufacture and assessment of the stability of samples of silver lactate. To the best of our knowledge, a validated stability‐indicating LC assay method for silver lactate based on lactic acid is reported for the first time.
Hydrochemical Formation Mechanisms and Quality Assessment of Groundwater with Improved TOPSIS Method in Pengyang County Northwest China
Authors: Peiyue Li , Hui Qian , Jianhua Wu
Published: April 2012

Inverse geochemical modeling was used in this paper to quantitatively study the formation mechanisms of groundwater in Pengyang County, China. An improved TOPSIS method based on entropy weight was used to perform groundwater quality assessment in this area. The assessment results show that the groundwater in the study area is fit for human consumption and the high concentrations of some elements can be attributed to the strong water‐rock interactions. The inverse geochemical modeling reveals that the dominant reactions in different parts of the study area are different. In the south part of the study area, the precipitation of sodium montmorillonite, calcite and the dissolution of gypsum, fluorite, halite, albite and dolomite as well as CO2 dissolution and cation exchange are the major water‐rock interactions, while in the north part, the leading reactions are the precipitation of gypsum, dolomite, sodium montmorillonite, fluorite, the dissolution of calcite and albite and the CO2 emission and cation exchange are also important. All these reactions are influenced by the initial aquatic environment and hydrodynamic conditions of the flow path.
A Comparative Study of Carbon Nanotubes Synthesized from Co/Zn/Al and Fe/Ni/Al Catalyst
Authors: Dikio Ezekiel Dixon
Published: April 2012

The catalyst systems Fe/Ni/Al and Co/Zn/Al were synthesized and used in the synthesis of carbon nanotubes. The carbon nanotubes produced were characterized by Field Emission Scanning Electron Microscope (FE-SEM), Energy Dispersive x‐ray Spectroscopy (EDS), Raman spectroscopy, Thermogravimetric Analysis (TGA) and Transmission Electron Microscope (TEM). A comparison of the morphological profile of the carbon nanotubes produced from these catalysts indicates the catalyst system Fe/Ni/Al to have produced higher quality carbon nanotubes than the catalyst system Co/Zn/Al.
Preparation Characterization and Antibacterial Studies of Chelates of Schiff Base Derived from4‐Aminoantipyrine, Furfural and o‐phenylenediamine
Authors: Suresh M. S. , Prakash V.
Published: April 2012

A new series of transition metal complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) were synthesized from the Schiff base ligand derived from 4‐aminoantipyrine, furfural and o‐phenylenediamine. The structural features were derived from their elemental analyses, infrared, UV‐visible spectroscopy, NMR spectroscopy, thermal gravimetric analyses, ESR spectral analyses and conductivity measurements. The data of the complexes suggested square planar geometry for the metals with primary valency two. Antimicrobial screening tests were performed against bacteria. The comparative study of the MIC values of the Schiff base and its metal complexes indicate that the metal complexes exhibit greater antibacterial activity than the free ligand.
Mild and Efficient Oxidation ofPrimary and Secondary Alcohols Using NiO2/Silica Gel System (Solvent Free)
Authors: Kooti Mohammad , Amirian Soodabeh
Published: April 2012

Oxidation of alcohols by nickel peroxide and silica gel system using grinding method has been studied. In the oxidation process, NiO2 is converted to NiO, which is recoverable.
Optimizing Gingival Biotype Using Subepithelial Connective Tissue Graft: A Case Report and One-Year Followup
Authors: Grover Harpreet Singh , Yadav Anil , Yadav Priya , Nanda Prashant
Published: April 2012

Gingival recession is the exposure of root surfaces due to apical migration of the gingival tissue margins. The principal objectives of treating a gingival recession are to achieve better esthetics and reduce hypersensitivity. The gingival biotype is an important modifying factor in the treatment of gingival recession. The purpose of this paper is to highlight the significance of changing the soft tissue biotype to a more favorable one while attempting root coverage, to achieve more stable and long-lasting results using subepithelial connective tissue graft.
X‐Ray Diffraction and SEM Investigation of Solidification/ Stabilization of Nickel and Chromium Using Fly ash
Authors: Patil Ranjana A. , Zodape Sangesh P.
Published: April 2012

The main thrust of the paper is mechanism of immobilization of nickel(Ni) and chromium(Cr) metal sludge by solidification/stabilization using lime fly ash and sand (LFAS). The mineralogy of fly ash used for the study has been determined on the basis of x‐ ray diffraction analysis (XRD). Attempts have been made to investigate the consequences of interaction of heavy metal ion with constituents of lime fly ash sand composite on the basis of XRD studies and scanning electron microscopy (SEM, except chromium).
Development of Validated Spectrophotometric Methods for Estimation of Ethacridine Lactate in Pharmaceutical Formulations
Authors: Unnisa Aziz , Manasa N. , Ravali P. Lakshmi
Published: April 2012

Ethacridine lactate (EAL) is an antiseptic in solutions of 0.1%. It is also used as an agent for second trimester abortion. Two simple and sensitive spectrophotometric methods (Method A and Method B) were developed for the estimation of EAL in pharmaceutical formulations. Method A is based on the condensation of the primary aromatic amino group of ethacridine lactate with an aromatic aldehyde (p‐Dimethylamino‐ cinnamaldehyde) to form a chromophore with absorption maximum of 600nm. Method B is based on redox reaction followed by complex formation of EAL with IO3-Metol reagent to form a stable chromogen, which can be estimated at 520 nm. Method A obeys Beer’s law in the concentration range of 2 to 12 μg/mL and method B in the range of 20 to 100 μg/mL. Interference studies were conducted to see the influence of excipients with the proposed methods. The common excipients usually present in dosage forms do not interfere in the proposed method A and method B. The optical characteristics, regression analysis data and precision of the methods were also calculated. The methods were validated for use in routine quality control of EAL in pharmaceutical formulations.
Cloud Point Extraction of Toxic Reactive Black 5 Dye from Water Samples Using Triton X‐100 as Nonionic Surfactant
Authors: Mousavi Raziyeh , Nekouei Farzin
Published: April 2012

A surfactant mediated cloud point extraction (CPE) procedure has been developed to remove color from wastewater containing reactive black 5, using triton x‐100 (TX‐100) as non‐ionic surfactant. The effects of the concentration of the surfactant, pH, temperature and salt concentration on the different concentrations of dye have been studied and optimum conditions were obtained for the removal of reactive black 5 (RB 5). The concentration of RB 5 in the dilute phase was measured using UV‐Vis spectrophotometer. It was found that the separation of phases was complete and the recovery of RB 5 was very effective in the presence of NaCl as an electrolyte. The results showed that up to 600 mg L-1 of RB 5 can quantitatively be removed (>97%) by cloud point extraction procedure in a single extraction using optimum conditions.
Palladium Nanoparticles Immobilized on Poly(vinyl chloride)‐Supported Pyridinium as an Efficient and Recyclable Catalyst for Suzuki‐Miyaura Cross‐Coupling Reaction
Authors: Zhou Bo , Li Yi-Qun
Published: April 2012

The palladium nanoparticles immobilized on the polymeric surface of poly(vinyl chloride)‐supported pyridinium (PVC‐Py‐Pd0) were achieved by a simple procedure by applying the corresponding functionalized polymer and palladium chloride in ethanol solution. The as‐prepared catalyst (PVC‐Py‐Pd0) was found to be air and moisture stable and exhibits significant catalytic activity for Suzuki‐Miyaura cross‐coupling reaction of various aryl halides and phenylboronic acid under milder operating conditions. The procedure presented here showed several merits such as short reaction time, simple experimental and isolated procedure and excellent yields of products. Furthermore, the catalyst can be easily recovered and reused for at least six times with consistent activities.
Stability Constants of Mixed Ligand Complexes of Transition Metal(II) Ions with Salicylidene‐4‐methoxyaniline as Primary Ligand and 5‐Bromosalicylidene‐4‐nitroaniline as Secondary Ligand
Authors: Nadkarni N. G. , Mangaonkar K. V.
Published: April 2012

Binary and ternary complexes of the type M‐Y and M‐X‐Y [M = Mn(II), Ni(II), Cu(II) and Zn(II); X = salicylidene‐4‐methoxyaniline and Y=5‐bromosalicylidene‐4‐nitroaniline] have been examined pH‐metrically at 27±0.5 °C and at constant ionic strength, μ= 0.1 M (KCl) in 75 : 25(v/v) 1,4‐dioxne‐water medium. The stability constants for binary (M‐Y) and ternary (M‐X‐Y) systems were calculated. The relative stability (Δ log KT) values of the ternary complexes with corresponding binary complexes for all the metal(II) ions in the present study found to be negative indicating that ternary 1:1:1 (M‐X‐Y) complexes are less stable than binary 1:1 (M‐Y) complexes. In the ternary system studied, the order of stability constants of mixed ligand complexes with respect to the metal ions was found to be Cu(II) > NI(II) > Mn(II) > Zn(II); which is same as in the corresponding binary (M‐Y) systems.
Corrosion Behaviour of Mild Steel in Acidic Medium in Presence of Aqueous Extract of Allamanda Blanchetii
Authors: Anand B. , Balasubramanian V.
Published: April 2012

The inhibition efficiency (IE) of an aqueous extract of Allamanda blanchetii (Purple) in controlling corrosion of mild steel which has been evaluated by weight loss method in the absence and presence of corrosion inhibitor at different time intervals at room temperature. The result showed that the corrosion inhibition efficiency of Allamanda blanchetii was found to vary with different time interval and different acid concentrations. Also, it was found that the corrosion inhibition behavior of Allamanda blanchetii is greater in sulphuric acid than citric acid medium. So Allamanda blanchetti can be used as a good inhibitor for preventing mild steel material. The surface analysis study confirms the corrosion of the mild steel and its inhibition by the inhibitor Allamanda blanchetii.
Development of Polymethylmethacrylate Based Composite for Gas Sensing Application
Authors: Devikala S. , Kamaraj P.
Published: April 2012

Gas detection instruments are increasingly needed for industrial health and safety, environmental monitoring and process control. Conductive polymer composites have various industrial applications. The composite prepared by mixing carbon black with polymethylmethacrylate (PMMA) has very good gas sensing applications. The gas sensors based on carbon nanotube/polymer, ceramic and metal oxide composites such as epoxy, polyimide, PMMA / Barium titanate and tin oxide have also been developed. In the present work, a new composite has been prepared by using PMMA and ammonium dihydrogen phosphate (ADP). The PMMA/Ammonium dihydrogen phosphate (PMADP) composites PMADP 1 and PMADP 2 were characterized by using Powder XRD. The thick films of the composite on glass plates were prepared by using a spin coating unit at 9000 rpm. The application of the thick film as gas sensor has been studied between 0 and 2000 seconds. The results reveal that the thick film of PMADP composite can function as a very good gas sensor.
Fast and Efficient Method for Imination of N‐Aminorhodanine Using Inorganic Solid Support under Microwave Irradiation and Classical Heating
Authors: Tabatabaee Masoumeh , Heravi Majid M. , Sharif Mahboubeh , Esfandiyari Fatemeh
Published: April 2012

Reaction of N‐aminorhodanine with various aldehydes under classical heating (in various solvents, using hydrochloric acid or acetic acid as catalyst) or by using Al2O3 under microwave irradiation in solventless system led to the corresponding imines (2 or 3). All the compounds have been characterized by elemental analyses, NMR and IR spectroscopy. Results indicate that treatment of N‐aminorhodanine with aldehydes in acetonitrile as solvent or under solventless system led to the corresponding imines (2a-2e), while reactions were performed in solvent such as methanol 3a-3e was formed as products of ring cleavage and imination.
Potentiometric Sensors for Pr(III) Based on N-N᾽o‐Phenylene‐bis(salicylideneimine) Using Epoxy Resin and PVC as Binding Materials
Authors: Harish K. Sharma , Neha Verma , Kapoor J. K.
Published: April 2012

Praseodymium(III) ion selective electrodes have been prepared using N-N᾽o‐phenylene‐bis(salicylideneimine) as a suitable electro‐active material. Several membranes comprising of varying compositions of electro‐active material with epoxy resin and polyvinylchloride (PVC) as binding materials were prepared. However the one with composition 50% Schiff᾽s base and 50% binder was found to exhibit best performance. The sensor with epoxy resin as binder presents a linear dynamic range of 1.0×10-6 to 1.0×10-1 M with a Nernstian slope of 19.9 mV/decade. The sensor has a quick response time. (less than 10 s). The reproducibility of the electrode is about 6 months without any considerable, noticeable potential divergence. The sensor is effective in pH range of 3.00‐8.62. In case of PVC as binding material; the results are compared for same composition of electro‐active material. The sensor presents a linear dynamic range of 1.0×10-6 to 1.0×10-1 M with a slope of 14.0 mV/decade. The response time of the sensor is found to be 20s with a reproducibility of 4 months. The sensor is effective in pH range of 2.97‐8.90. Effect of internal solution was studied and both the electrodes could satisfactorily be used in partially non‐aqueous medium. Selectivity coefficients for both the electrodes have been determined by FIM (fixed interference method) with respect to many rare earth metal ions, alkali & alkaline earth metal ions and some transition metal ions. Both the electrodes were successfully employed as indicator electrode in the potentiometric titration of Pr(III) ions with oxalic acid and EDTA.
Effects of HBV Genetic Variability on RNAi Strategies
Authors: Panjaworayan Nattanan , Brown Chris M.
Published: April 2012

RNAi strategies present promising antiviral strategies against HBV. RNAi strategies require base pairing between short RNAi effectors and targets in the HBV pregenome or other RNAs. Natural variation in HBV genotypes, quasispecies variation, or mutations selected by the RNAi strategy could potentially make these strategies less effective. However, current and proposed antiviral strategies against HBV are being, or could be, designed to avoid this. This would involve simultaneous targeting of multiple regions of the genome, or regions in which variation or mutation is not tolerated. RNAi strategies against single genotypes or against variable regions of the genome would need to have significant other advantages to be part of robust therapies.
An Improved, Highly Efficient Method for the Synthesis of Bisphenols
Authors: S. Patil L. , S. Suryawanshi V. , B. Pawar O. , D. Shinde N.
Published: April 2012

An efficient synthesis of bisphenols is described by condensation of substituted phenols with corresponding cyclic ketones in presence of cetyltrimethylammonium chloride and 3‐mercaptopropionic acid as a catalyst in extremely high purity and yields.
Bayesian Image Restoration Using a Large‐Scale Total Patch Variation Prior
Authors: Chen Yang , Yu Weimin , Li Yinsheng , Yang Zhou , Luo Limin , Chen Wufan
Published: April 2012

Edge‐preserving Bayesian restorations using nonquadratic priors are often inefficient in restoring continuous variations and tend to produce block artifacts around edges in ill‐posed inverse image restorations. To overcome this, we have proposed a spatial adaptive (SA) prior with improved performance. However, this SA prior restoration suffers from high computational cost and the unguaranteed convergence problem. Concerning these issues, this paper proposes a Large‐scale Total Patch Variation (LS‐TPV) Prior model for Bayesian image restoration. In this model, the prior for each pixel is defined as a singleton conditional probability, which is in a mixture prior form of one patch similarity prior and one weight entropy prior. A joint MAP estimation is thus built to ensure the iteration monotonicity. The intensive calculation of patch distances is greatly alleviated by the parallelization of Compute Unified Device Architecture(CUDA). Experiments with both simulated and real data validate the good performance of the proposed restoration.
Solid‐Phase Extraction with Diethyldithiocarbamate as Chelating Agent for Preconcentration and Trace Determination of Copper, Iron and Lead in Fruit Wine and Distilled Spirit by Flame Atomic Absorption Spectrometry
Authors: Chanthal Saksit , Suwamart Nongnoot , Ruangviriyachai Chalerm
Published: April 2012

Some heavy metals that present in wine and distilled spirit as background contamination are generally found at trace level particularly less than detection limit of common analytical techniques including flame atomic absorption spectrometry (FAAS). Thus, preconcentration method of the trace metals was developed. The optimum conditions for diethyldithiocarbamate (DDTC) complexes of Cu, Fe and Pb were then investigated for the preconcentration step using C18 solid‐phase extraction prior to measurement by FAAS. The preconcentration factor of 15‐fold was obtained with the appropriate ratio of sample volume used (150 mL) to 10 mL final volume giving their method recoveries of Cu, Fe and Pb found in the ranges of 96.5‐107, 102‐116 and 91.7‐107%, respectively. Precision determinations (n = 10) for 0.1 mg L-1 of Cu, Fe and Pb each in a model solution were 3.7, 4.2 and 7.1 %RSD respectively. The detection limits (3SD) of Cu, Fe and Pb were found to be 1.4, 3.3 and 5.7 μg L-1, respectively. The developed method was applied to ten samples of local fruit wines and five samples of distilled spirits, resulting in the ranges of 0.012‐0.80 and 0.12‐8.8 mg L-1 for Cu; 0.18‐3.4 and 0.036‐0.29 mg L-1 for Fe and 0.0070‐0.053 and 0.014‐0.026 mg L-1 for Pb, respectively. Therefore, the method is simple and inexpensive for routine analysis of the trace metals in these samples to overcome limit of detection of the instrument used.
Mineral Composition, Total Phenol Content and Antioxidant Activity of a Macrolichen Everniastrum cirrhatum (Fr.) Hale (Parmeliaceae)
Authors: Kekuda T. R. Prashith , Vinayaka K. S. , Swathi D. , Suchitha Y. , Venugopal T. M. , Mallikarjun N.
Published: April 2012

In the present study, we investigated for the first time mineral composition, total phenol content and antioxidant activity of a foliose macrolichen Everniastrum cirrhatum (Fr.) Hale (Parmeliaceae) from Bhadra wildlife sanctuary, Karnataka, India. Mineral content of the lichen was estimated by Atomic absorption spectrophotometer after acid digestion. The secondary metabolites were detected by thin layer chromatography (TLC) and phytochemical assays. The lichen material was extracted with methanol in soxhlet apparatus. Total phenol content was estimated by folin ciocalteu method. Antioxidant activity was determined by DPPH, Ferric reducing and metal chelating assays. Among the principal elements, calcium was found in high concentration followed by magnesium, potassium and phosphorus. Among trace elements, iron was detected in high amount followed by zinc, manganese and copper. The DPPH radical scavenging activity was found to be dose dependent with an IC50 of 6.73 μg/mL. In ferric reducing assay, the absorbance increased with the concentration of extract suggesting reducing power. The extract exhibited good metal chelating activity with an IC50 value of 29.28 μg/mL. Total phenol content was 101.2 mg tannic acid equivalents per gram of extract. Phytochemical analysis revealed the presence of alkaloids, saponins, tannins and terpenoids. TLC revealed atranorin, salazinic acid and protolichesterinic acid. The lichen can be consumed as a source of minerals required for the body as appreciable amount of minerals has been detected. The marked antioxidant activity may be attributed to the presence of phenol content in the extract. Further studies on isolation of metabolites and their bioactivities are under investigation.
Oligodeoxynucleotide Containing Disulphide Bond Stabilizes Triplex DNA Structure
Authors: Kumar Ajay
Published: April 2012

The triplex formation of disulphide containing oligonucleotide with duplex DNA using melting temperature studies is reported. The stability of the triplex formed with disulphide containing oligonucleotide was compared with unmodified oligonucleotide and C‐5 propyne deoxyuridine containing oligonucleotide. Melting temperature (Tm) values of the triplexes formed with disulphide containing oligonucleotide were found to be 37 °C and 46 °C at pH 7 and 6 respectively. The triplexes formed with C‐5 propyne deoxyuridine substituted oligonucleotide showed Tm values at 27 °C and 42 °C at pH 7 and 6. The Tm values of the triplexes formed with unmodified oligonucleotide were found to be 18 °C and 32 °C at pH 7 and 6 respectively. This clearly demonstrates that disulphide containing oligonucleotide stabilzes triplex DNA structure better than unmodified oligonucleotide as well as C‐5 propyne deoxyuridine containing oligonucleotide when targeted with duplex DNA at both the mentioned pH values.
Spectrophotometric Study of Complexation Between Some New N2O2‐Schiff Bases and Some Transition Metal Ions in Nonaqueous Solvents
Authors: Shokrollahi A. , Ghaedi M. , Montazerozohori M. , Kianfar A. H. , Ghaedi H. , Khanjari N. , Noshadi S. , Joybar S.
Published: April 2012

The complexation reaction between some transition and heavy metal cations and some new N2O2 Schiff bases in acetonitrile (AN) or methanol (MeOH) as nonaqueous solvents at 25 °C and 0.05 M tetraethylammonium perchlorate (TEAP) were investigated by spectrophotometric method. The stoichiometry and overall stability constants of complexes have been evaluated by computer refinement of abs‐mole ratio data, using the KINFIT program. All investigated metal ions form 1:1 ML, 1:2 ML2 or 2:1 M2L complexes with studied ligands. The effect of structure on the complexation was investigated.
Preconcentration of Cr(III) from Natural Water by Modified Nano Polyacrylonitrile Fiber by Methanolamine
Authors: Moghimi Ali
Published: April 2012

Modified nano polyacrylonitrile fiber (PANF) was prepared by adding acrylic fibers to methanolamine (MMA) with different concentration solutions. The stability of a chemically modified nano polyacrylonitrile fiber especially in concentrated hydrochloric acid which was then used as a recycling and pre‐concentration reagent for further uses of modified nano polyacrylonitrile fiber. The application of this modified nano polyacrylonitrile fiber for sorption of a series of metal ions was performed by using different controlling factors such as the pH of metal ion solution and the equilibration shaking time by the static technique. Cr(III) was found to exhibit the highest affinity towards extraction by these modified nano polyacrylonitrile fiber phases. The pronounced selectivity was also confirmed from the determined distribution coefficient (Kd) of all the metal ions, showing the highest value reported for Cr(III) to occur by modified nano polyacrylonitrile fiber. The modified nano polyacrylonitrile fiber for selective extraction of Cr(III) were successfully accomplished in aqueous solution as well as preconcentration of low concentration of Cr(III) (60 pg mL-1) from natural tap water with a preconcentration factor of 100 for Cr(III) and then off‐line Cr(III) in water samples were determined by flame atomic absorption.
Synthesis and Oxidation ofCobalt(II) Pheophytin‐α Complex
Authors: Dikio Ezekiel D. , Isabirye David A.
Published: April 2012

The mechanism of oxidation of natural pheophytin‐a incorporated with cobalt as the central metal ion has been investigated. Natural pheophytin‐aextracted from spinach was metallated with cobalt(II) to form the complex, cobalt(II) pheophytin‐α [Cophe]. The complex was characterized by Ultraviolet and Visible, Fourier Transform Infrared and Electrospray ion Mass Spectroscopy. The synthesis of cobalt(II) pheophytin‐a was carried out and the effect of the substitution on the chlorophyll macrocycle was studied by the reaction of hexaaquachromium(III) cation. The presence of cobalt as the central metal ion increases the energies of the chlorophyll main absorption transitions. The oxidation of the cobalt(II) pheophytin‐α, [Cophe] by hexaaquachromium(III) cation in dilute hydrochloric acid has been studied and found to follow first‐order kinetics. Rate constants for the oxidation reaction at 313, 322.8 and 332.9 K were found to be 5.4×10-5, 1.8×10-4 and 5.9×10-4/s respectively. An outer‐sphere mechanism has been proposed for the oxidation of cobalt(II) pheophytin‐α.
New Robust Exponential Stability Criterion for Uncertain Neutral Systems with Discrete and Distributed Time‐Varying Delays and Nonlinear Perturbations
Authors: Pinjai Sirada , Mukdasai Kanit
Published: April 2012

We investigate the problem of robust exponential stability for uncertain neutral systems with discrete and distributed time‐varying delays and nonlinear perturbations. Based on the combination of descriptor model transformation, decomposition technique of coefficient matrix, and utilization of zero equation and new Lyapunov functional, sufficient conditions for robust exponential stability are obtained and formulated in terms of linear matrix inequalities (LMIs). The new stability conditions are less conservative and more general than some existing results.
Adsorption Study of Some Sulphanilic Azo Dyes on Charcoal
Authors: Mohammed H. J. , Kadhim B. J. , Mohammed Aseel Sh.
Published: April 2012

Studies on the removal of two dyes (sulphanilic azo antipyrine and sulphanilic azo imidazole) from aqueous solution by adsorption on charcoal as an adsorbent were carried out. A series of experiments were under taken in a batch adsorption technique to access the effect of the process variables i.e. contact time, initial dye concentration, initial pH, adsorbent dose and temperature. Adsorbent dosage (0.1 g) higher value for both dyes. The equilibrium in the solution was observed within (35 min) of two sulphanilic dyes on charcoal. The equilibrium isotherms for both dyes were determined to describe the adsorption process. The results showed that the equilibrium data was fitted by of the Freundlich isotherms on charcoal surface. The result obtained shows that the adsorption isotherm for both dyes on charcoal was according to Giles classification. The thermodynamic factors such as ∆Η, ∆G and ∆S were calculated.
Synthesis, Spectral Characterization and Antimicrobial Evaluation of Schiff Base Cu(II), Ni(II) and Co(II) Novel Macrocyclic Complexes
Authors: Kumar Gajendra , Kumar Amit , Shishodia Nupur , Garg Y. P. , Yadav B. P.
Published: April 2012

A series of Schiff base macrocyclic complexes of the type [HLMX2] where M = Cu(II), Ni(II), Co(II) and X = Cl, OAc have been synthesized by condensation of acetylacetone and thiocarbohydrazide (2:2) in the presence of divalent metal salt in methanolic medium. The complexes have been characterized with the help of elemental analysis, conductance measurements, magnetic measurements and their structural configuration have been determined by various spectroscopic (Electronic, IR, 1H NMR, 13C NMR, GCMS) techniques. Electronic and magnetic moments of the complexes indicate that the geometries of the metal centers are octahedral. These metal complexes were also tested for their antimicrobial activities to assess their inhibiting potential.
Dual‐Wavelength Spectral Correction Method for Simultaneous Determination of V(IV) and V(V)
Authors: Mirzajani R. , Kiasat A. R.
Published: April 2012

Simultaneous determination of V(IV) and V(V) was performed when the calibration matrix was obtained using beta‐corrected spectral data. The method is based on the reaction between V(IV) and V(V) and 4‐(2‐pyridylazo)‐resorcinol (PAR) as a ligand at pH 6. Using β‐correction technique true absorbance of chelate produced can be calculated because the quantity of absorbance, which has related to the fraction of reagent that reacted with metal ion and has been subtracted when reagent applied as reference by this correction has compensated. The parameters controlling behavior of the system were investigated and optimum conditions selected. Calibration model was constructed based on absorption spectra in the 540‐600 nm range for 25 different mixtures of V(IV) and V(V) in the concentration ranges of 0.10‐4.00 µgmL−1 of V(IV) and 0.10‐5.00 µgmL−1of V(V). Applying this method to the analysis of mixtures of V(IV) and V(V) in waste water and soil samples with total relative standard error of less than 4.3% validated the proposed method.
Method Development and Validation for Determination of Voglibose in Tablet Formulation Using LC‐MS/MS
Authors: Rajput Mithlesh , Dahiya Meenakshi , Kumari Premlata , Kalra Kamini , Aggarwal Manjeet , Khandal R. K.
Published: April 2012

Voglibose is a potent α glucosidase inhibitor, used for the treatment of diabetes mellitus. For quantitative determination of voglibose in pharmaceutical formulations of low doses, simple, sensitive, accurate and precise LC‐MS/MS method using electrospray ionization in positive mode was developed and validated. The method was found linear in the concentration range of 25.0‐1200 ηg/mL with a correlation coefficient of 0.9998. The limit of detection (LOD) of the method was found to be 1.5 ηg/mL and limit of quantitation (LOQ) was achieved at 3.0 ηg/mL. The recoveries of voglibose from spiked samples at different concentration levels were found in the range of 98‐102%. The proposed method was found suitable for quantitation of voglibose and for the determination of uniformity of content of the dosage units of the tablet formulations.
Stability Constants of Mixed Ligand Complexes of Transition Metal(II) Ions with N‐(2‐Hydroxy‐1‐naphthylidene)‐2,6‐diisopropylaniline as Primary Ligand and N‐(2‐Hydroxybenzylidene)‐2,3‐dimethylaniline as Secondary Ligand
Authors: Mapari A. K. , Mangaonkar K. V.
Published: April 2012

Binary and ternary complexes of the type M‐Y and M‐X‐Y [M = Co(II), Ni(II), Cu(II) and Zn(II); X = N‐(2‐hydroxy‐1‐naphthylidene)‐2,6‐diisopropylaniline and Y = N‐(2‐hydroxybenzylidene)‐2,3‐dimethylaniline] have been examined pH‐metrically at 27±0.5 °C and µ = 0.1 M in 75: 25% (v/v) 1,4‐dioxne‐water medium. The logarithms of the values of stability constants for binary (M‐Y) and for ternary (M‐X‐Y) systems were calculated.
Synthesis and Characterization of Tetrakis(4‐oxo‐piperidinium ethylene acetal) Bis Sulfate Hexahydrate
Authors: Marouani H. , Rzaigui M. , Al-Deyab S. S.
Published: April 2012

Chemical preparation, x‐ray characterization, IR spectroscopy and thermal analysis of a new sulfate (C7H12O2NH2)4(SO4)2.6H2O, are reported. The atomic arrangement can be described by layers formed by sulfate anions (SO -24) and water molecules connected by hydrogen bonds O‐H…O. These inorganic layers are developed around ab planes at z = 0 and z = 1/2 and are interconnected by the H‐bonds created by organic groups. All the hydrogen bonds, the Van der waals contacts and electrostatic interactions between the different entities give rise to a three‐dimensional network in the structure and add stability to this compound. The thermal behaviour and the IR spectroscopic studies of this new sulfate are discussed.