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Chelating terpolymer resin was synthesized from anthranilic acid and 2-amino pyridine with formaldehyde to remove the heavy metal ions present in the solutions. The synthesized terpolymer resin was characterized by spectral techniques such as FTIR, NMR (1H and 13C) and elemental analysis to elucidate the structure of the resin. The physico-chemical parameters have also been evaluated for the terpolymer resin. The surface morphology of the terpolymer resin without the metal ion uptake and with the incorporation of the metal ion was examined by scanning electron microscopy. The chelation ion-exchange property of the terpolymer resin was evaluated by batch equilibrium method for specific metal ions viz. Fe3+, Co2+, Ni2+, Cu2+, Zn2+, and Pb2+. The study was extended to three variations such as evaluation of metal ion uptake in presence of various electrolytes in different concentrations, evaluation of the distribution of metal ion uptake at different pH ranges and evaluation of the rate of metal ion uptake at different time intervals. The adsorption isotherm was evaluated by means of Langmuir and Freundlich isotherm models. The order of the kinetics was also determined and the resin follows first order kinetics which shows that physisorption may be involved in the ion-exchange process. From the results, it was observed that the terpolymer resin acts as an excellent cation-exchanger. Compared to the commercially available phenolic and polystyrene resins, the synthesized terpolymer resin showed an excellent ion-exchange capacity with the selected metal ions.

2-Amino-6-nitro-benzothiazole and thiosemicarbazide with formaldehyde (BTF) terpolymer was synthesized by the condensation polymerization technique. The elemental analysis and physico-chemical parameters of the terpolymer were measured. This chelation terpolymer was characterized by infrared, electronic and nuclear magnetic resonance ( 1 H & 13 C NMR) spectral studies. The molecular weight of the terpolymer was determined by gel permeation chromatography (GPC). Surface analysis of the terpolymer was analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) method. The thermal stability of the terpolymer was analyzed by thermogravimetric analysis (TGA). The cation-exchange property of the terpolymer was determined by batch equilibrium method with the effect of pH, contact time and electrolytes. The reusability of the resin was also studied to estimate the effectiveness of the terpolymer resin.

Poly(fluorene-alt-carbazole) appended with meso-tetraphenylporphyrin (MTPPC) linked through oxyethylene spacer and the parent poly(N-hexyl-2,7-carbazole-alt-9,9-di-n-hexyl fluorene) (P1) were synthesized and characterized. Optical absorption properties of the polymers containing 5% of MTPPC (P2) and 10% of MTPPC (P3) in the polymer backbone show extended optical absorption toward long wavelength compared to the parent polymer P1. Optical absorption studies of the polymers showed that polymer P1 has absorption at 384 nm in solution, whereas polymers P2 and P3 have absorption at 384 nm corresponding to polymer backbone and soret band at 421 nm with Q bands at around 518 and 554 nm in solution. P1 shows photoluminescence emission around 417 nm, whereas P2 and P3 fall around 656 nm. Thermal, electrochemical, and quenching studies of the polymers have been studied and the details are reported.

Degradation of high-density polyethylene (HDPE) films blended with 0.5, 1.0, and 2.0% metal ions (MIs, chromium = 36%, silicon = 8%, aluminum = 4%, and chlorine = 2%) and 5, 10, and 20% potato starch were studied under two different abiotic treatment conditions (they were either heated to 70�C or exposed to UV at 300-400 nm) for a period of 100 days. The addition of metals did not affect the mechanical strength of the polymer, whereas starch blending did. The latter turned the polymer yellow. HDPE with MIs exhibited higher levels of oxidation than the other samples. UV treatment affected the mechanical strength of the MI-blended HDPE more than the other additive or the thermal treatment. The formation of extractable oxygenated compounds and unoxidized low-molecular-weight hydrocarbons increased with increasing concentration of additives in HDPE. The surface energy in all cases increased, this indicated that the polymers turned hydrophilic. The maximum weight loss (28%) was seen in the 2% MI-blended HDPE exposed to UV followed by the 20% starch-blended polymer exposed to heat (24%). These results indicate a synergy between blending and the treatment strategy, this also suggests an optimal waste-disposal strategy. � 2012 Wiley Periodicals, Inc.

Hexagonal BiPO4·xH2O and Bi0.95Eu0.05PO4·xH2O nanoparticles were synthesized by a polyol-mediated method employing diethylene glycol. The powder X-ray diffraction revealed the phase purity and isostructural nature of both undoped and Eu3+-doped BiPO4. The monoclinic Bi0.95Eu0.05PO4 was obtained by heating the hexagonal Bi0.95Eu0.05PO4·xH2O at 600 °C. The microscopical characterization revealed the formation of nanocrystalline materials. Water molecules present in the bismuth precursor favoured the formation of hexagonal phase at low temperature. The role of DEG molecules in arresting the particle growth during the phase transformation of Bi0.95Eu0.05PO4 from hexagonal to monoclinic was observed. The synthesized materials were characterized using different spectroscopic techniques such as FT-IR, Raman, 31P MAS-NMR, DRUV-Vis and PL. The difference in the crystal structures and symmetries is clearly reflected in the spectral results of hexagonal and monoclinic Bi0.95Eu0.05PO4. The structure-property relations were studied to derive its importance from both fundamental and technological aspects.

Highly graphitic carbons are obtained by precipitating carbon from molten steel inoculated with bismuth. Scanning electron microscopy images show that the products have a potato peel morphology. The inoculant leads to a breaking of the local symmetry of the graphitic structure as evidenced by Raman spectroscopic studies. The products exhibit flat charge-discharge profiles below about 200 mV versus LrVLi, reversible capacities even exceeding the theoretical limit of 372 mAh/g for perfectly graphitic structures, low first-cycle irreversible capacities, and sustained hundreds of cycles.

This paper presents in brief the formulation of the rigid body separation dynamics that are useful for the design and analysis of satellite separation systems using the helical compression spring mechanism. In satellite launch vehicle chronology, safe injection of the satellite into the desirable orbit is an important final task. The body rate of the satellite during separation should be within the satellite control capabilities. The Taguchi method is employed in order to understand the influencing parameters in the separation process. Statistical analysis has been carried out to identify the probability distribution function for reliability and safety assessment of the satellite separation of a launch vehicle. Using the response surface method (RSM), an empirical relation is obtained for the body rate of the satellite in terms of the 28 physical parameters. The RSM results are compared with the Taguchi simulation results. Reliability and safety assessments are made on the satellite separation of a typical launch vehicle.

The steady state behaviour of a single server non-Markovian queue with multiple vacations and controlled optional re-service is analysed. A batch of customers arrive according to Poisson with rate A, whereas the bulk service is rendered by a single server with a minimum batch size of ‘a and maximum of ‘b’. The service times follow a general distribution. At the completion of an essential service, the leaving batch of customers may request for a re-service with probability n. However, the re-service is rendered only when the number of customers waiting in the queue is less than ‘a’. If no request for re-service is made after the completion of an essential service and numbers of customers in the queue is less than ‘a, then the server will avail a vacation of a random length. When the server returns from vacation and if the queue length is still less than ‘a’ he avails another vacation so on until the server finds ‘a’ customers in the queue. After the completion of an essential service and numbers of...

Terpolymer ligand was synthesized from 8-hydroxyquinoline and anthranilic acid with formaldehyde (QAF) by solution condensation in an acid medium. Polychelates of Cu(II), Ni(II), Zn(II), and Pb(II) were prepared using the terpolymer as ligand. The ligand and chelates were characterized by elemental analysis, TGA, DSC, FTIR, electronic absorption, and NMR spectroscopy. The activation energy was calculated for the ligand and its polychelates formation by the Freeman-Carroll method. The ligand and its polychelates possess antimicrobial activity for certain bacteria such as Staphylococcus aureus, Escherichia coli, and fungi Aspergillus niger and Candida albicans. The surface morphology of the ligand and its polychelates was established by SEM.

We are reporting the preparation and characterization of nano-titanium dioxide and silica. The corrosion resistance performance of these nanopigments in silicone as well as silicone–polypyrrole Interpenetrating Polymer Network has been evaluated by impedance spectroscopy. The capacitance and resistance exerted by this nanocomposite coating were compared with the microcomposite coating and found that the nanocomposite coatings has the resistance in the order of 108 Ω cm2 in 3% sodium chloride solution, which is more than the microcomposite coating. The comparison of heat resistance performance of these composite coatings indicates that nanocomposite coatings exhibit higher heat resistance property than the microcomposite coatings.

This paper presents in brief the formulation for lateral and longitudinal dynamics associated with the separation and pull out of an ongoing functional stage from the spent stage of a multistage launch vehicle using separation motors as jettisoning system. Taguchi method is employed to understand the influencing parameters in the separation process. It is possible to minimize the number of Monte-Carlo simulations (MCS) by Taguchi's orthogonal array. Statistical analysis has been carried out to identify the probability distribution function (PDF) for reliability and safety assessment of the stage separation system. The tolerances on the pull out time, relative velocity, lateral gap and longitudinal clearances between the separating bodies are taken into account while examining the non-occurrence of collision between the separating bodies. Lateral gap/dynamic clearance between stages are found to be very vital from collision aspects. This study clearly demonstrates the applicability of Taguchi method to capture the essential Monte-Carlo simulation results in the stage separation process. The method of approach followed in this study will be useful to understand the dynamic behavior of the separating bodies during the stage separation process of multistage launch vehicles.

Polyol mediated synthesis for the preparation of tungsten trioxide and titanium doped tungsten trioxide has been reported. The reaction was carried out using chlorides of tungsten and titanium in diethylene glycol medium and water as the reagent for hydrolysis at 190 deg. C. Formation of a blue coloured dimensionally stable suspension of the precursor materials was observed during the course of the reaction. The particle sizes of the precursor materials were observed to be around 100 nm. The precursor materials were annealed to give tungsten trioxide and titanium doped tungsten trioxide. The precursor materials were characterised using TGA/DTA, FT-IR, optical spectra, SEM, TEM and powder XRD methods. It was observed that the doping of titanium could be effected at least up to 10% of Ti in WO{sub 3}. The TGA/DTA studies indicated that WO{sub 3-x}.H{sub 2}O is the dominant material that formed during the polyol mediated synthesis. The XRD data of the annealed samples revealed that the crystalline phase could be manipulated by varying the extent of titanium doping in the tungsten trioxide matrix.

This paper presents a systematic formulation for the simulation of rigid body dynamics, including the short period dynamics, inherent to stage separation and jettisoning parts of a satellite launcher. This also gives a review of various types of separations involved in a launch vehicle. The problem is sufficiently large and complex; the methodology involves iterations at successively lower levels of abstraction. The best choice to tackle such problems is to use state-of-the-art programming technique known as object oriented programming. The necessary classes have been identified to represent various entities in the launch vehicle separation process (e.g., gravity, aerodynamics, propulsion and separation mechanisms etc.). Simple linkages are modelled with suitable objects. This approach helps the designer to simulate a launch vehicle separation dynamics and also to analyse separation system performance. To examine the influence of the design variables on the separating bodies, statistical analyses have been performed on the upper stage separation process and pull out of ongoing stage nozzle from the spent stage of a multistage rocket carrier using retro rockets.

In this paper a M X / G ( a , b )/1 queueing system with multiple vacations, setup time with N -policy and closedown times is considered. On completion of a service, if the queue length is ξ , where ξ a , then the server performs closedown work. Following closedown the server leaves for multiple vacations of random length irrespective of queue length. When the server returns from a vacation and if the queue length is still less than ‘ N ’, he leaves for another vacation and so on, until he finds ‘ N ’ ( N > b ) customers in the queue. That is, if the server finds at least ‘ N ’ customers waiting for service, then he requires a setup time ‘ R ’ to start the service. After the setup he serves a batch of ‘ b ’ customers, where b ⩾ a . Various characteristics of the queueing system and a cost model with the numerical solution for a particular case of the model are presented.

This paper presents in brief the formulation used for the studies of lateral and longitudinal dynamics associated with separation and pull out of an ongoing functional stage from the spent stage of a multistage launch vehicle using retro rockets as jettisoning system. A fourth-order Runge-Kutta method is employed to solve the governing nonlinear differential equations of motion to obtain the state vectors of the separating bodies. A statistical method is adapted to account for the off nominal design parameters of the bodies undergoing separation and the jettisoning system. The tolerances in magnitude of the pull out time, relative velocity, lateral gap and longitudinal clearances between the separating bodies were used to find out the nonoccurrence of collision between the separating bodies. This procedure helps in designing and adapting a suitable jettisoning system to achieve collision free separation of multistage launch vehicle stages.

Electrochemical biosensors have become very important tools in analytical chemistry because of their advantages like accuracy, high sensitivity and easy handling, This article describes electrochemical detection of acetic acid based on the fungus Fusarium solani. The biosensor employed for the study of assimilation of substrates was fabricated by coupling the immobilized membrane with the DO probe using dialysis tubing, A microbial dispersion containing 0.2 g of wet weight of the organisms per mL was used for immobilization upon cellulose nitrate membrane. The membrane retaining the fungus was placed on the Teflon membrane of the oxygen electrode so that the fungus was trapped between the two membranes. The linear range was found to be between 2 and 70 ppm (v/v) of acetic acid. A polypropylene net increases the lifetime of the sensor due to its retention of humidity in the net. By dipping the electrochemical probe onto buffer (pH 7.2), the sensor was found to have an extended lifetime of 120 days with about 800 determinations.

Electrochemical biosensors have become very important tools in analytical chemistry because of their advantages like accuracy, great sensitivity and easy handling. This article reports on the electrochemical detection of ethanol based on the fungus Aspergillus niger. The fungus was isolated from polyurethane waste, at a factory in India. The fungal assimilation of ethanol came to light, when detailed biochemical characterization of the fungus for alcohols, organic acids, and amino acids was studied using cyclic voltammetry. The fungus was cultured in Czepek-Dox media. A dissolved oxygen (DO) probe was fabricated using a gold cathode, a platinum counter electrode and Ag/AgCl reference electrode. The biosensor employed for the assimilation characterization was fabricated by coupling the immobilized membrane with the DO probe using dialysis tubing. A microbial dispersion containing 0.2 g (wet weight) of the organisms/mL was used for immobilization upon cellulose nitrate membrane. The membrane retaining the fungus was placed on the Teflon membrane of the oxygen electrode so that the fungus was trapped between the two membranes. The maximum detectable concentration was 35.3 ppm (v/v) and the linear range was between 1 and 32 ppm (v/v) of ethyl alcohol. By dipping the assembly with the microbe in phosphate buffer, the sensor was found to have an extended lifetime of 90 days with about 1000 determinations.

A procedure is developed for the determination of Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn in water by inductively coupled plasma-atomic emission spectrometry (ICP-AES) after preconcentration on a piperidine dithiocarbamate supported polyurethane foam. The sorbed elements are subsequently eluted with 4 mol L−1 HNO3, and the acid eluates are analysed by ICP-AES. A 20-mL disposable syringe served as a chromatographic preconcentration column. The sorption recoveries of elements except Co and Cr were higher than 97%. The method is also applied for the analysis of natural water samples.

Recent developments in the field of flexible electronics motivated the researchers to start working in verdict of new flexible substrate for replacing the existing rigid glass and flexible plastics. Flexible substrates offer significant rewards in terms of being able to fabricate flexible electronic devices that are robust, thinner, conformable, lighter and can be rolled away when needed. In this work, a new flexible and transparent substrate with the help of organic materials such as Polydimethylsiloxane (PDMS) and tetra ethoxy orthosilicate (TEOS) is synthesized. Transmittance of about 90–95% is acquired in the visible region (400–700[Formula: see text]nm) and the synthesized substrate shows better thermal characteristics and withstands temperature up to 200[Formula: see text]C without any significant degradation. Characteristics such as transmittance ([Formula: see text]), absorption ([Formula: see text]), reflectance ([Formula: see text]), refractive index ([Formula: see text]) and extinction coefficient ([Formula: see text]) are also reported.

Divalent europium-activated alkaline-earth-metal chlorophosphate luminophores (MCAP:Eu 2+ ; M=Ca, Sr, Ba) have been prepared by self-propagating high-temperature (SPHT) synthesis in one pot employing the corresponding nitrates/chlorides, urea and diammonium hydrogen phosphate. The synthesized materials have been characterized by X-ray diffraction, photoluminescent emission spectroscopy, thermogravimetry, scanning electron microscopy and particle size analysis. The formation of chloroapatite depends on the nature of acid used in the combustion mixture. The photoluminescent emission efficiency and particle size distribution are found to depend on the amount of metal chloride used and on the sintering temperature. The results obtained are discussed with respect to the processing method employed.

Environmental issues raise concern on restrict the use of nondegradable polymers and encourage the development of degradable once. This study is carried out was to understand the rate of biodegradation of untreated and pretreated (100 C or UV for 10 days) polypropylene (PP), pro-oxidant blended (MI-PP) and starch blended polypropylenes (ST-PP) with two different fungal strains, Phanerochaete chrysosporium NCIM 1170 (F1) and Engyodontium album MTP091 (F2). About 18.8% and 9.42% gravimetric weight loss and 79% and 57% TGA weight loss (at 400 C) were observed with UV pretreated MI-PP in 1 year with F2 and F1 strains respectively. The amount of lacasse produced by the organism and biomass attached on the polymer surface are correlated with TGA weight loss (0.6–0.93). The formation of extractable oxygenated compounds and unoxidized low-molecular weight hydrocarbons are high in pretreated and blended samples. These results indicate blending and pretreatment strategy leads to an optimal waste-disposal strategy.

Yttrium oxide doped with trivalent europium has been prepared by self-propagating high temperature (SPHT) synthesis, also known as combustion synthesis, with nitrogen-based fuels. The materials synthesized have been characterized by X-ray diffraction, scanning electron microscopy, and luminescent emission spectroscopy. Crystallite size, powder density, and photoluminescent-emission intensity/efficiency are found to depend on the fuels used. The phosphor products were sintered with and without sintering aids. The results obtained are discussed with respect to the processing method employed.

A universal biochemical oxygen demand (BOD) sensor that can be used for the analysis of all types of organic pollutants is the objective of current researchers working in the area of biosensors. Development of such type of sensor involves the proper choice of a microorganism that can assimilate a wide spectrum of organic compounds. This study has led to the screening of many microorganisms and in this process we were able to identify Torulopsis candida as an attractive alternate for Trichosporon cutaneum. The BOD sensor employing T. candida was fabricated and evaluated in the batch mode as well as under flow conditions. The response time, linear range of estimation of BOD and storage life of the immobilized microbe and the assimilation spectrum have been studied.

The increasing legal and customer demands on passive safety of automobiles have to be fulfilled under the conditions of shortened development times and cost reductions. Today the design process of a bus with regard to its crashworthiness function is driven by a virtual development. A wide range of different applications has to be covered by simulation influencing the design of body-in-white, interior and exterior trim, chassis and power train. In recent days more emphasis has been given to Passenger bus rollover analysis and side impact but the study of frontal impact behaviour of the passenger bus is ignored. The finite element analysis is used for estimating the damage of the passenger bus due to the frontal crash. The vehicle model is allowed to frontal crash with rigid material. The deformation and displacement characteristics of the structure are analyzed at different speeds. Geometric modeling of the bus structure has been created by using CATIA cad package and discritized by ANSYS LS-Dyna. The numerical simulation is carried out for different velocities of bus structure. The results of displacement during collision are plotted on the graph. Some improvements were suggested in the body structure after analysing different types of crack initiators.Copyright © 2012 by ASME

SUMMARYIn conclusion, first time we report that SnCl 2 candope PAni-EB form by producing SnO 2 and HCl.The formed HCl doped the quinoid segments of theE.B structure in a conventional way to form conduct-ing PAni salt and SnO 2 is deposited on the surfaceof the polymer concomitantly to give conductingPAni-SnO 2 composite. In this method of preparation(composite A), tin oxide particles are deposited onPAni fibers. In the case of in situ polymerization(composite B), the composite is a homogeneous mix-ture of some free SnO 2 particles, SnO 2 on PAni andas well as SnO 2 encapsulated/embedded in PAni.The conductivity of the samples A and B increasedsignificantly due to the presence of SnO 2 nanopar-ticles, where the tin oxide particles are crystallizedin tetragonal (t-SnO 2 ) structure. In this study, it isalso established that composite A and B exhibitedimproved electrochemical property compared withpure PAni. The composite B showed enhancedpseudo capacitance as high as 219 F g 1 .The authors thank the directors of IICT and CECRIfor their constant encouragement, unstinted support.References

Large number of biochemical activities and electron behavior have a very close relationship with life forms and living cells [1], which makes the study of physiological and biochemical characteristics an important area in analytical chemistry. In recent years, researchers have developed rapid methods of assessment of cell proliferation [2–3], including reports on methods involving ATP bioluminescence [4], antibody-direct epifluorescent filter technique [5], enzyme immunoassays [6, 7], polymerase chain reaction [8], resonant mirror biosensor [9], quartz crystal microbalance biosensor [10], dielectric measurement [11], electron transfer in protein [12], and the electric impedance sensing systems [13]. The applications of direct voltammetry of cell cultures in the detection of viable microbes in biological samples have been reported [14–16]. Recent research has demonstrated that the live microbes, Tetrahymena shanghaiensis [17] and the Saccharomyces cerevisiae [18], could be monitored using cyclic voltammetry (CV). An attempt has been made here to extend this for fungal strains. The conventional method of the studies on the growth phases of fungi is cumbersome and time consuming because the time period required for the growth of the fungi is in terms of days, while for bacterial strains, all the phases of growth are completed in a few hours. This manuscript discusses the voltammeric behavior of the fungus, Aspergillus niger that was isolated from polyurethane waste scraps.

Anodic oxidation of 1′,8′-dimethyl- and other 1′,8′-disubstituted a.c -biladiene salts affords novel cyclized products. In addition to porphyrin, an unconjugated macrocyclic intermediate product resulting from oxidadve cyclizatfon during porphyrin synthesis is isolated, structurally identified, and characterized with regard to its spectroscopy, electrochemical behavior and chemical reactivity. The formation of a novel homoporphyrin from a 1′-ethoxycarbonylmethy-8′-(2-methoxycarbonylethyl)- a,c -biladiene salt is also briefly discussed.

Several covalently linked bisporphyrin systems, free-base (H 2 P---H 2 P), hybrid bisporphyrins (Zn---H 2 P) and Zn(II) dimers (ZnP---ZnP) and their 1:1 molecular complexes with sym 1,3,5-trinitrobenzene have been investigated by optical absorption and emission, and magnetic resonance spectroscopic methods. In these systems, two porphyrin units are linked singly through one of the meso aryl groups via ether linkages of variable length. The bisporphyrins cooperatively bind a molecule of a π-acceptor; 1,3,5-trinitrobenzene (TNB). The binding constant values vary with interchromophore separation. Maximum binding is observed in the bisporphyrin bearing a two-ether covalent linkage. It is found that TNB quenches the fluorescence of the two porphyrine units in a selective manner. It is suggested that a critical distance between the two porphyrin units is necessary for the observance of maximum cooperative intermolecular binding with an acceptor.

A supramolecular host—guest assembly based on zeolite YMHCF (M  Ni, Co) is examined electrochemically. Using well-known metal hexacyanoferrate (MHCF) redox chemistry in response to alkali metal cations, revealed by cyclic voltammetric “signatures”, we present the first results on the effects of the zeolite medium and confirm the intrazeolitic presence of MHCF complexes.

Phosphosilicate molecular precursor for the synthesis of NASICON, natrium super ionic conductor, Na1+xZr2SixP3−xO12 (x = 1 and 2) has been devised and prepared by the hydrolysis of tetraethoxysilane (TEOS) employing sodium phosphate solution. The molecular precursor was reacted with Zr(OC3H7)4 in ethanol under solvolytic condition to yield nano precursor material of NASICON. This material was annealed at high temperature to yield phase-pure NASICON. The molecular precursor was characterized using 31P NMR, FTIR spectral data, powder XRD pattern and TG/DTA studies. The structure of the molecular precursor was deduced from the powder XRD data, which indicates the presence of edge sharing tetrahedral arrangement of −O−Si−O−P−O−Si− chain. The NASICON precursor material was characterized using TG/DTA, FTIR, TEM, SEM, MAS 31P NMR and XRD. The conductivity of the synthesized NASICON material was measured using the pellet annealed at 900 °C and was found to be 5.5 x10−3 S cm−1. The details on the preliminary inves...

Anodic oxidation of 1′,8′-dimethyl- and other 1′,8′-disubstituted a.c -biladiene salts affords novel cyclized products. In addition to porphyrin, an unconjugated macrocyclic intermediate product resulting from oxidadve cyclizatfon during porphyrin synthesis is isolated, structurally identified, and characterized with regard to its spectroscopy, electrochemical behavior and chemical reactivity. The formation of a novel homoporphyrin from a 1′-ethoxycarbonylmethy-8′-(2-methoxycarbonylethyl)- a,c -biladiene salt is also briefly discussed.

A detailed study using the cyclic voltammogram was done on the live cells of Aspergillus terreus. The peak current values were obtained for different days of growth and plotted against time. The response of cyclic voltammogram showed the phases of the growth of the fungus. The growth curve obtained matched well with the conventional methodology, which assesses the increase of dry weight of the organisms against time. The electrochemical method is more advantageous because it is easy to assess and consumes less time. Further the electrochemical method clearly shows the decline phase which is generally not very defined in the conventional method of assessment of the growth curve. It was confirmed by further experiments that the metabolites were responsible for the anodic peak and not the biomass. Further work is in progress in order to analyze the metabolite(s) that is/are responsible for the anodic peak.

Recently there has been a considerable focus on the synthesis of nitrogen functionalized graphene for energy storage and conversion. Herein, we report a simple, economical and facile process for the synthesis of nitrogen containing graphene composite which can be scaled up for mass production by using a nitrogen containing organic compound, ethylenediaminetetraacetic acid (EDTA) and graphene oxide as precursors. From the XRD studies, the increase in the interlayer distance between the graphene sheets confirms the functionalization of graphene sheets and the FT-IR spectroscopic analysis revealed the presence of N-containing functional groups in N-doped graphene sheets. XPS analysis confirms the chemical nature of N-containing functional groups, and TG analysis showed the amount of EDTA loaded on the graphene sheets. This composite exhibits a large specific capacitance of 290 F g−1 at 0.1 A g−1 with a capacitance retention of 67% and 58% at high current densities of 10 and 20 A g−1, respectively, thereby showing superior rate capability. In addition, it showed long-term electrochemical stability through 6000 charge–discharge cycles even at a high current density of 5 A g−1 with a specific capacitance loss of 2%.

Mn3O4-reduced graphene oxide (RGO) nanocomposites were prepared by chemical decomposition of the manganese hexacyanoferrate (MnHCF) complex directly on the graphene surface. XRD studies revealed the formation of crystalline hausmannite Mn3O4 nanocubes in the as-prepared nanocomposites without any heat treatment. The FE-SEM images showed the formation of Mn3O4 nanocubes on the graphene surface in the as-prepared nanocomposites. HR-TEM studies confirmed the homogeneous dispersion of ∼25 nm Mn3O4 nanocubes on graphene nanosheets. The amount of Mn3O4 nanocubes and graphene in the nanocomposites was estimated using TGA analysis from room temperature to 800 °C in air. The FT-IR and Raman spectroscopic analysis confirmed the functional groups in the nanocomposites and defects in graphene nanosheets in the nanocomposites. Cyclic voltammetry and galvanostatic charge-discharge experiments demonstrated a high specific capacitance of 131 F g(-1) in 1 M Na2SO4 electrolyte at a current density of 0.5 A g(-1) for the RGM-0.5 nanocomposite. A capacitance retention of 99% was observed for 500 charge-discharge cycles at a current density of 5 A g(-1), which conformed the excellent stability of the RGM electrodes. The prepared Mn3O4-RGO nanocomposites are promising for electrochemical energy storage.

The identification and biochemical characterization of microbial species by electrochemical methods have helped to develop microbial sensors that are rapid and effective. In this article, we present results of biochemical characterization of five fungi, the assimilation and biochemical characterization of various substrates and tolerance to selected inhibitors. The results are based on the respiratory rate and assimilatory profile of these fungi and are more rapid and reliable. The experimental results are discussed here with reference to individual fungus. Further, the advantages of the electrochemical assimilation for the biochemical characterization of the microbes have been discussed.

Fusarium solani, the fungus isolated from polyurethane waste scraps, was studied for its voltammetric response. The peak current values were obtained for different days and were plotted against time. This electrochemical method based on the voltammetric response showed all the four phases of the growth of the fungus. The growth curve obtained matched well with the conventional methodology, which is obtained by assessing the increase of dry weight of the organisms against time. The electrochemical method is more advantageous than the conventional method because the conventional method is very time consuming and difficult to work with. Further, the electrochemical method clearly shows the decline phase, which is generally not very well defined in the conventional method of assessment of the growth curve. It was confirmed by further experiments that the metabolites were responsible for the anodic peak and not the fungal biomass. Identification of the metabolites that are responsible for the anodic peak is presently being studied.

This retrospective study documents a strong correlation between tuberculin reactivity and the subsequent development of active tuberculosis in student nurses. 12% of the 25 student nurses with tuberculin reactions above 20 mm developed tuberculosis over a period of 2 years, compared to only 0.3% of the 341 student nurses with reactions of 20 mm or less. The implications of these findings for preventive therapy are discussed.

A young man presented with primary multi-drug resistant tuberculosis. The institution of second-line regimes with insufficient efficacy due to clinical inexperience, unreliable sensitivity reports and the inavailability of second-line drugs led to the development of an organism that was resistant to ten anti-tuberculous drugs. Accurate sensitivity testing done in an overseas laboratory enabled the institution of a six-drug regimen that has resulted in clinical cure.

A graded nano-alloy of Au100−xPtx (x = 7, 15, 23, 32, 40, 51, 62, 73 and 86) nanoparticles (NPs) formed by co-reduction of HAuCl4 and H2PtCl6 and the details are presented in this work. Au100−xPtx NPs were characterized using surface plasmon resonance (SPR) absorption spectroscopy and transmission electron microscopy (TEM). The NPs were dispersed in Vulcan carbon (Au100−xPtx/C) and annealed at 250, 400, 600 and 800 °C. The as-formed and annealed materials were characterized using TEM, high resolution transmission electron microscopy (HR-TEM), powder X-ray diffraction (XRD), cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS). The CV studies indicate excess Pt on the surface, which is corroborated by XPS and HR-TEM results. The XRD data show that Vegard's law is obeyed by the as-formed material and the materials annealed at 250 and 400 °C, indicating that these materials are not nano-alloys. The studies clearly indicate that the formation of Au100−xPtx NPs is kinetically controlled rather than being controlled by the thermodynamic stability. The results demonstrate the formation of graded alloys of Au100−xPtx NPs. Pt excess in the graded nano-alloy is reflected favourably in the electrochemical oxidation of small organics. In the methanol oxidation reaction (MOR), the peak current value per mg of Pt increases as a function of x, reaches a maximum value at x = 23 and the ratio of forward current to reverse current for MOR reached an unprecedented value of 6.7, which shows the catalyst’s stability against poisoning by carbonaceous intermediates.

Bulk-synthesized silicon carbide, hitherto considered inactive for electrochemical lithium insertion, is demonstrated as a potential high-capacity, long-cycling anode material for lithium-ion batteries. In this study, we show that cubic (3C polytype) nano SiC, prepared by a chemical vapour deposition (CVD) method, delivers a reversible lithium insertion capacity of about 1200 mA h g−1 over 200 cycles.

Twenty-seven inmates from a detention centre in Perak were evaluated for possible causes of their ankle oedema. Physical examination and biochemical evaluation did not show any evidence of renal or hepatic dysfunction. The cardiac origin of their problem was suggested by the presence of other signs of heart failure in three of them and by radiological evidence of cardiomegaly in 40% of them. All the patients who returned for review demonstrated a prompt clinical response to thiamine replacement therapy.

Three East Timorese immigrants presented with signs and symptoms of heart failure in early December 1992. One of them also had features of peripheral neuropathy. Another collapsed within 24 hours of admission and attempts at resuscitation failed. The other two showed dramatic response to oral thiamine therapy. An investigation into their dietary history established gross deficiency in fresh vegetables.

8 We acticipate that this reaction, while quite useful in its own right, may also be the prototype for other novel transformations based on transition-metal-centered radicals.'* As a first step in this direction we plan to explore intermolecular additions of epoxides to activated olefins. Supplementary Material Available: Details of isolation and characterization (13C NMR, 'H NMR, HRMS, elemental analysis) of products 1-8 (4 pages). Ordering information is given on any current masthead page.

8 We acticipate that this reaction, while quite useful in its own right, may also be the prototype for other novel transformations based on transition-metal-centered radicals.'* As a first step in this direction we plan to explore intermolecular additions of epoxides to activated olefins. Supplementary Material Available: Details of isolation and characterization (13C NMR, 'H NMR, HRMS, elemental analysis) of products 1-8 (4 pages). Ordering information is given on any current masthead page.