Abstract  Four dinuclear and three mononuclear Zn(II) complexes of phenol-based compartmental ligands (HL(1)-HL(7)) have been synthesized with the aim to investigate the viability of a radical pathway in catecholase activity. The complexes have been characterized by routine physicochemical studies as well as X-ray single-crystal structure analysis: [Zn(2)(H(2)L(1))(OH)(H(2)O)(NO(3))](NO(3))(3) (1), [Zn(2)L(2)Cl(3)] (2), [Zn(2)L(3)Cl(3)] (3), [Zn(2)(L(4))(2)(CH(3)COO)(2)] (4), [Zn(HL(5))Cl(2)] (5), [Zn(HL(6))Cl(2)] (6), and [Zn(HL(7))Cl(2)] (7) [L(1)-L(3) and L(5)-L(7) = 2,6-bis(R-iminomethyl)-4-methylphenolato, where R= N-ethylpiperazine for L(1), R = 2-(N-ethyl)pyridine for L(2), R = N-ethylpyrrolidine for L(3), R = N-methylbenzene for L(5), R = 2-(N-methyl)thiophene for L(6), R = 2-(N-ethyl)thiophene for L(7), and L(4) = 2-formyl-4-methyl-6-N-methylbenzene-iminomethyl-phenolato]. Catecholase-like activity of the complexes has been investigated in methanol medium by UV-vis spectrophotometric study using 3,5-di-tert-butylcatechol as model substrate. All complexes are highly active in catalyzing the aerobic oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylbenzoquinone (3,5-DTBQ). Conversion of 3,5-DTBC to 3,5-DTBQ catalyzed by mononuclear complexes (5-7) is observed to proceed via formation of two enzyme-substrate adducts, ES1 and ES2, detected spectroscopically, a finding reported for the first time in any Zn(II) complex catalyzed oxidation of catechol. On the other hand, no such enzyme-substrate adduct has been identified, and 3,5-DTBC to 3,5-DTBQ conversion is observed to be catalyzed by the dinuclear complexes (1-4) very smoothly. EPR experiment suggests generation of radicals in the presence of 3,5-DTBC, and that finding has been strengthened by cyclic voltammetric study. Thus, it may be proposed that the radical pathway is probably responsible for conversion of 3,5-DTBC to 3,5-DTBQ promoted by complexes of redox-innocent Zn(II) ion. The ligand-centered radical generation has further been verified by density functional theory calculation.

Abstract  A facile one step reaction between 6-aminocoumarin and anthracene-9-carboxaldehyde has resulted in a novel fluorescent probe, 6-((anthracen-9-yl) methyleneamino)-2H-chromen-2-one (AC) which is capable of selectively detecting intracellular Cr3+ in contaminated living cells under a fluorescence microscope. The binding of AC with Cr3+ is well characterized by different spectroscopic techniques. The binding constant values in CH3CN-water (9 : 1, v/v) and methanol-water (9 : 1, v/v) solutions have been estimated to be 1.1 x 10(5) and 3.1 x 10(5) respectively using the Benesi-Hildebrand equation. The detection limit for Cr3+ is 0.5 x 10(-6) M. The developed method has been used for speciation studies in a fast and environment friendly way using least amounts of samples, non-hazardous chemicals and solvents.

Abstract  Electrochemical studies of new binary Pt-MoC electrocatalysts prepared by carbothermal-reduction method have been developed. The XRD and XPS characterization allows to determine the structure of core-shell Mo-carb-particles, with a reduced-Mo core (Mo2C, MoO2 and/or Mo-0) and a MoO3-shell (2-3 nm). Upon adding Pt, Pt interacts with MoO3-shell. The oxidation of: (i), CO by cyclic voltamperometry (CV) followed by in situ differential electrochemical mass spectrometry (DEMS); and, (ii), methanol by CV and chronoamperometric techniques were carried out at room temperature. The results show an improvement in the Pt-tolerance to CO-presence with the presence of reduced Mo-carb phases (decreasing the potential in 65 mV(RHE)), without significant difference between the binary catalysts. An additional Mo-redox pre-peak is observed at 0.4(RHE) V. This process is related to Mo4+-to-Mo6+ oxidation developed on the MoO3-shell of Mo-carb-particles, which is catalysed by Pt. This Mo-oxidation/reduction couple is affected (shifts towards more negative potentials) by the CO adsorption on Pt-centres. DEMS results show that CO-oxidation occurs in the potential region of this Mo-oxidation. The binary Pt-Mo-carb catalysts show similar behaviour for methanol oxidation as those for CO-stripping ones. Nevertheless, the chronoamperometric curves display a catalytic performance improvement (highest activity and stability) using Pt-MoC/CBv catalyst regarding the other binary catalysts. This best behaviour with Mo2C-phase enhances to increases the temperature up to 60 degrees C (typical value for low-temperature FCs in-operation). Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Abstract  The analysis of weakly basic drugs such as verapamil by reverse-phase liquid chromatography remains a problem, particularly when present in combination with other drugs such as amphoteric compounds like trandolapril. In this study, the simple, accurate, precise and fully validated RP-LC method for the simultaneous determination of verapamil and trandolapril in combined dosage forms has been developed. The LC method allowed quantitation over the ranges of 0.50-18.00 mu g/mL and 0.05-1.00 mu g/mL for verapamil and trandolapril, respectively. The detection limits were found to be 0.008 mu g/mL and 0.018 mu g/mL for verapamil and trandolapril, respectively. Moreover, pK(a) values of verapamil and trandolapril were determined via the dependence of the retention factor on the pH of the mobile phase for ionizable substances. The effect of the mobile phase composition on the ionization constant was studied by measuring the pKa at different methanol-water mixtures, ranging 50-65% (v/v). It was shown that RP-HPLC was suitable for the high throughput analysis of the combination of verapamil and trandolapril. The method also allows a number of cost and time saving benefits and can be readily employed for the analysis of pharmaceutical formulations. The method has been verified, without any interference from excipients, for the concurrent analysis of these compounds in tablets.

Abstract  Nanoporous metals have been used to enhance electrocatalysis. The origin of their capability is understood on the basis of enlarged surface area. On the other hand, the nanoconfined space of nanoporous metals can significantly affect the electrochemical efficiency. Moreover, molecular dynamics in nanoconfined spaces is capable of offering much more chances of interaction between a redox molecule and a metal surface. These unique properties come from simply nanoporous structure and suggest new opportunity to innovative electrocatalysts in the future. This review addresses recent advances in the field of nanoporous metals and discusses respective important electrocatalytic applications.

Abstract  A high-performance liquid chromatographic method with an evaporative light-scattering detector has been developed for the separation and quantitative analysis of four underivatized long chain fatty acids in four different oil matrices. An isocratic elution mode using methanol/water/ acetic acid and an Agilent Eclipse XDB-C18 analytical column was used. Calibration curves of the four fatty acids (FA) were well correlated (r(2) > 0.999) within the range of 1-10 mg mL(-1) for linoleic acid, 0.8-10 mg mL(-1) for stearic acid and 0.5-10 mg mL(-1) for the other FA. Four oil samples were examined; camellia oil, olive oil, Brucea javanica oil and sesame oil. Good agreement was found with the standard gas chromatographic (GC) method. The proposed method offers distinct advantages over the official GC method; better separation and precision, and the sample components do not need to be derivatized.

Abstract  The kinetic model for simulating the mechanism of the promoted effect of methanol on the NOxOUT process has been established and it mainly includes the optimal sub-mechanisms respectively for the NOxOUT process and the chemical reaction of methanol. The oxygen concentration does not obviously influence the maximum NO reduction efficiency in the range of 1-6 %, but the temperature window is overall shifted to lower temperature zone with oxygen concentration increased. Meanwhile, the mole ratio of urea to nitric oxide by a factor of 2 should be maintained between 1.5 and 2 from both the efficiency and running cost view. Also, ample residence time of 300/T-400/T s must be guaranteed for the reduction occurring thoroughly. Methanol does not compromise the maximum NO reduction efficiency and broadens the temperature window towards low temperature zone. The promoted mechanism of methanol on the NOxOUT process is the abundant OH formation through the methanol regenerative reaction of CH2OH/CH3O+H2O=CH3OH+OH and methanol should be maintained at 50-100 ppm for an obvious promoted effect. During the co- injection of methanol and urea, the ""ammonia slip"" is depressed, especially at 1173 K where the promoted effect on NO reduction is obvious, but emission of nitrous oxide is also markedly increased at this temperature.

Abstract  We have investigated the photocatalysis of partially deuterated methanol (CD3OH) and H2O on TiO2(110) at 400 nm using a newly developed photocatalysis apparatus in combination with theoretical calculations. Photocatalyzed products, CD2O on Ti-sc sites, and H and D atoms on bridge-bonded oxygen (BBO) sites from CD3OH have been clearly detected, while no evidence of H2O photocatalysis was found. The experimental results show that dissociation of CD3OH on TiO2(110) occurs in a stepwise manner in which the O-H dissociation proceeds first and is then followed by C-D dissociation. Theoretical calculations indicate that the high reverse barrier to C-D recombination and the facile desorption of CD2O make photocatalytic methanol dissociation on TiO2(110) proceed efficiently. Theoretical results also reveal that the reverse reactions, i.e, O-H recombination after H2O photocatalytic dissociation on TiO2(110), may occur easily, thus inhibiting efficient photocatalytic water splitting.

Abstract  A comparison among the monolithic and randomly packed reactors for the methanol conversion to propylene (MTP) process has been presented in this work by modeling and simulation based on adiabatic heterogeneous reactor models including the interactions of mass and heat transfer and chemical reactions between the gas and catalyst phases and inside the catalyst phase. Simulation results showed that the monolithic catalyst intensifies significantly the methanol conversion efficiency and the propylene selectivity, compared with the randomly packed catalyst pellets. The monolithic reactor can achieve a propylene selectivity high up to 88% with a methanol conversion of 95% at a space time of 7 g(catalyst) h mol(MeOH)(-1), but the random one does 82% with 80% at 27. For a complete methanol conversion, the monolithic catalyst amount is five times less than the random pellet catalyst in an adiabatic reactor. Furthermore, the higher cell density and thinner wall of the monolith produce the higher methanol conversion and propylene selectivity. (C) 2012 Elsevier B.V. All rights reserved.

Abstract  Plasma-induced graft polymerization of acrylic acid was carried out on polycaprolactone filament using low pressure oxygen plasma. The degree of grafting was studied by varying parameters such as the medium of grafting, reaction temperature, monomer concentration and storage conditions. Addition of ferrous sulphate suppressed the homopolymer formation but resulted in a lower degree of grafting. However, the presence of methanol increased the graft yield. The equilibrium degree of grafting exhibited strong dependence on monomer concentration, reaction temperature and active centers's concentration created upon plasma exposure. From the reaction kinetics, the order of dependence on the monomer concentration was found to be 1.1. The degree of grafting was strongly dependent on storage temperature following plasma treatment. At very low temperature, significant concentrations of active centers could be preserved for graft polymerization. Graft polymerization on the surface led to the filling of valleys by grafted polymer chains resulting in increased hydrophilicity and topographical changes as measured by contact angle, SEM and AFM experiments. (C) 2012 Published by Elsevier Ltd.

Abstract  A new validated high-performance thin-layer chromatographic (HPTLC) method has been developed for the simultaneous quantitation of four antipsychotic indole alkaloids (IAs), reserpiline (RP, 1), alpha-yohimbine (YH, 2), isoreserpiline (IRP, 3) and 10-methoxy tetrahydroalstonine (MTHA, 4) as markers in the leaves of Rauwolfia tetraphylla. Extraction efficiency of the targeted IAs from the leaf matrix with organic and ecofriendly (green) solvents using percolation, ultrasonication and microwave techniques were studied. Non-ionic surfactants, viz. Triton X-100, Triton X-114 and Genapol X-80 were used for extraction and no back-extraction or liquid chromatographic steps were used to remove the targeted IAs from the surfactant-rich extractant phase. The optimized cloud point extraction was found a potentially useful methodology for the preconcentration of the targeted IAs. The separation was achieved on silica gel 60F(254) HPTLC plates using hexane-ethylacetate-methanol (5:4:1, v/v/v) as mobile phase. The quantitation of IAs (1-4) was carried out using the densitometric reflection/absorption mode at 520 nm after post chromatographic derivatization using Dragendorffs reagent. The method was validated for peak purity, precision, accuracy, robustness, limit of detection (LOD) and quantitation (LOQ). Method specificity was confirmed using retention factor (R-f) and visible spectral (post chromatographic scan) correlation of marker compounds in the samples and standard tracks. (C) 2012 Elsevier B.V. All rights reserved.

Abstract  As anhydrous proton conductive membranes, sulfonated polysulfone (SPSU) and 1H-1,2,3-benzotriazole (BTri) hybrid membranes were prepared. The sulfonation of polysulfone was performed with trimethylsilyl chlorosulfonate, and high degree of sulfonation (134%) was obtained. The polymer electrolyte membranes, SPSU-BTriX, were prepared by blending of 1H-1,2,3-benzotriazole in SPSU. FTIR confirmed the sulfonation of PSU and the ionic interaction between sulfonic acid and benzotriazole units. Thermogravimetric analysis (TGA) analysis showed that the polymer electrolyte membranes are thermally stable up to approximately 200 degrees C. Scanning electron microscopy analysis indicated the homogeneity of the membranes. The maximum proton conductivity has been measured for SPSU-BTri2 as 3.6 x 10(-3) S/cm at 150 degrees C.

Abstract  The ability of the phenol-adapted Ralstonia eutropha to utilize formaldehyde (FD) as the sole source of carbon and energy was studied. Adaptation to FD was accomplished by substituting FD for glucose in a stepwise manner. The bacterium in the liquid test culture could tolerate concentrations of FD up to 900 mg L(-1). Degradation of FD was complete in 528 h at 30°C with shaking at 150 rpm (r = 1.67 mg L(-1) h(-1)), q = 0.035 g(FD) g(cell) (-1) h(-1). Substrate inhibition kinetics (Haldane and Luong equations) are used to describe the experimental data. At non-inhibitory concentrations of FD, the Monod equation was used. According to the Luong model, the values of the maximum specific growth rate (μ(max)), half-saturation coefficient (k(S)), the maximum allowable formaldehyde concentration (S(m)), and the shape factor (n) were 0.117 h(-1), 47.6 mg L(-1), 900 mg L(-1), and 2.2, respectively. The growth response of the test bacterium to consecutive FD feedings was examined, and the FD-adapted R. eutropha cells were able to degrade 1000 mg L(-1) FD in 150 h through 4 cycles of FD feeds. During FD degradation, formic acid metabolite was formed. Assimilation of FD, methanol, formic acid, and oxalate by the test bacterium was accompanied by the formation of a pink pigment. The carotenoid nature of the cellular pigment has been confirmed and the test bacterium appeared to be closely related to pink-pigmented facultative methylotrophs (PPFM). The extent of harm to soil exposed to biotreated wastewaters containing FD may be moderated due to the association between methylotrophic/oxalotrophic bacteria and plants.

Abstract  A systematic study of the nature, stability, and dynamics of surface species present under methanol steam reforming (MSR) conditions over Pd/Ga2O3 and Pd2Ga/Ga2O3 was performed by combining steady state and concentration modulation FTIR spectroscopy. This powerful I combination allowed us to obtain novel mechanistic insights into the selective pathway leading to the formation of H-2 and CO2 and thus to contribute to the understanding of the remarkably different catalytic properties of Pd/Ga2O3 and Pd2Ga/Ga2O3. Strongly enhanced formation of adsorbed formates at low temperatures was detected on Pd2Ga/Ga2O3. We ascribe the facilitated formation of these species to the presence of reactive oxygen sites in the Ga2O3 surface, which are formed during high-temperature reduction and formation of the intermetallic compound Pd2Ga. While the stability of involved formates is high under reaction conditions of methanol decomposition (i.e., in the absence of H2O), the entire adsorption system behaves more dynamically in the presence of water. We propose that the introduction of H2O into the system converts stable bridging- and bidentate formates into more reactive, monodentate species. These react either with adsorbed methoxy to methyl formate. (MFO) in the absence of water or with OH groups supplied by H2O to CO2 and H-2. The reaction with OH is faster, leading to a smaller concentration of intermediate monodentate formate under MSR conditions. MFO is easily decomposed into CO and CH3OH and therefore, it is unlikely to be an intermediate in the selective,MSR reaction to CO2 and H-2. While the formation of intermetallic particles by high temperature reduction is a prerequisite to achieving high MSR selectivity, our results suggest that the reaction sequence predominantly proceeds on the Ga2O3 surface, that is modified by the high temperature reduction and the formation of Pd2Ga, and is only promoted by the presence of the intermetallic particles.

Abstract  We have studied the decomposition of benzoyl and acetyl benzoyl peroxides in methanol-d(4) in response to temperature and microwave radiation. We have shown that chemically-induced dynamic nuclear polarization (CIDNP) can be observed even when the reactions are carried out in spectrometers with high magnetic fields. In this case, spin correlation persists in geminal radical pairs involving labile acyloxyl radicals. Regardless of the method used to initiate peroxide decomposition, the same amount of products are formed. Homolysis occurs according to a chain mechanism. The contribution of induced decomposition decreases over the course of the reaction. Dissolved oxygen molecules efficiently terminate the chain, decreasing the rate of peroxide decomposition. In the case of acetyl benzoyl peroxide, the product yield depends on the initiation mechanism: for microwave irradiation, the solvent molecules are more active while dissolved oxygen is less active than in thermolysis.

Abstract  Okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-2, and yessotoxin (YTX) are classes of lipophilic toxins found in marine animals. OA and DTX1 accumulation causes diarrhetic shellfish poisoning, a worldwide public health problem. Diarrhetic shellfish poisoning has not previously been reported in gastropods, which are widely consumed in Korea. Seasonal variation in marine lipophilic toxins in gastropods was investigated using liquid chromatography-tandem mass spectrometry. Eighty specimens of Neptunea cumingii, 65 specimens of Rapana venosa, and 95 specimens of Batillus cornutus were collected at the Tongyeong fish market on the southern coast of Korea between May 2009 and December 2010. OA, DTX1, and YTX were detected in meat and digestive glands in all gastropod species studied. Pectenotoxin-2 was not found in any sample tested. Lipophilic toxins were detected in the digestive glands of gastropods; no lipophilic toxin was detected in the salivary glands of the carnivorous gastropods, N. cumingii and R. venosa. The highest concentrations of OA (21.5 ng/g) and DTX1 (8.4 ng/g) were detected in the digestive glands of R. venosa, and the maximum concentration of YTX (13.7 ng/g) was found in the digestive glands of N. cumingii. The maximum toxicities in gastropod tissues were lower than the European standard for acceptable levels. The concentrations of lipophilic toxins in carnivorous gastropods showed a high degree of seasonal variation; lipophilic toxins in carnivorous gastropods were found predominantly in spring and summer. This is the first report of the occurrence of lipophilic toxins in Korean gastropods.

Abstract  According to the news reporters, the research concluded: "These data may provide support to establish more accurate astrochemical models and contribute to explain the influence of solar wind on condensed alcohols."

Abstract  Water balance mechanisms have been investigated in desert Drosophila species of the subgenus Drosophila from North America, but changes in mesic species of subgenus Drosophila from other continents have received lesser attention. We found divergent strategies for coping with desiccation stress in two species of immigrans group--D. immigrans and D. nasuta. In contrast to clinal variation for body melanization in D. immigrans, cuticular lipid mass showed a positive cline in D. nasuta across a latitudinal transect (10°46'-31°43'N). Based on isofemale lines variability, body melanization showed positive correlation with desiccation resistance in D. immigrans but not in D. nasuta. The use of organic solvents has supported water proofing role of cuticular lipids in D. nasuta but not in D. immigrans. A comparative analysis of water budget of these two species showed that higher water content, reduced rate of water loss and greater dehydration tolerance confer higher desiccation resistance in D. immigrans while the reduced rate of water loss is the only possible mechanism to enhance desiccation tolerance in D. nasuta. We found that carbohydrates act as metabolic fuel during desiccation stress in both the species, whereas their rates of utilization differ significantly between these two species. Further, acclimation to dehydration stress improved desiccation resistance due to increase in the level of carbohydrates in D. immigrans but not in D. nasuta. Thus, populations of D. immigrans and D. nasuta have evolved different water balance mechanisms under shared environmental conditions. Multiple measures of desiccation resistance in D. immigrans but reduction in water loss in D. nasuta are consistent with their different levels of adaptive responses to wet and dry conditions on the Indian subcontinent.

Abstract  According to news originating from Brisbane, Australia, by VerticalNews correspondents, research stated, "Acidic pH has previously been found to increase nitrous oxide (N2O) accumulation during heterotrophic denitrification in biological wastewater treatment.

Abstract  BMI's China Petrochemicals Report Q113 examines the short-term growth trends that are in play across the local industry as it ramps up capacity in an increasingly volatile export environment. This report analyses the latest developments and projects throughout the petrochemicals sectors and looks at how capacity growth could affect global markets. It also examines the performance of leading operators and their risk management and growth strategies.

Abstract  The vapor pressures of {1-hexene + methyl butyl ether (MBE)} and {1-hexene + methyl tert-butyl ether (MTBE)} binary mixtures and of the three pure components were measured by means of a static device at temperatures between (263 and 333) K. The data were correlated with the Antoine equation. From these data, excess Gibbs functions were calculated for several constant temperatures and fitted to a third-order Redlich-Kister equation using the Barker's method. Additionally, molar excess enthalpies, H-E, for the two binary systems have been measured at 303.15 K using an isothermal flow calorimeter. (C) 2012 Elsevier Ltd. All rights reserved.

Abstract  According to news reporting out of Aalborg, Denmark, by VerticalNews editors, research stated, "In this work the effects of reformate gas impurities on a H3PO4-doped polybenzimidazole (PBI) membrane-based high temperature proton exchange membrane fuel cell (HT-PEMFC) are studied.

Abstract  In order to dispense and utilize gaseous hydrogen, additional infrastructure may also be needed to produce, transport, store and dispense the hydrogen gas. [...]it would be beneficial to provide an alternative liquid hydrocarbon fuel product which can use existing infrastructure for production, transportation, storage and dispensing and which is not as volatile as hydrogen.

Abstract  A novel semiorganic nonlinear optical crystal bis (L-glutamine) potassium nitrate (BGPN) grown by slow evaporation technique at ambient temperature. The grown crystal surface has been analyzed by chemical etching and atomic force microscopy (AFM) studies. Amplitude parameters like area roughness, roughness average, valley height, valley depth, peak height, and peak valley height were measured successfully from AFM studies. Etching studies were carried out by various solvents like water, methanol and ethanol. The etching study indicates the occurrence of different types of etch pit patterns like striations and steplike pattern. The laser damage threshold energy has been measured by irradiating laser beam using a Q-switched Nd: YAG laser (1064?nm). Second harmonic generation (SHG) studies have been performed by famous Kurtz powder technique with reference to standard potassium dihydrogen phosphate single crystals (KDP). It is found from this technique that SHG efficiency of BGPN is in comparison to that of standard KDP crystals.

Abstract  3-hydroxy acids, 3-hydroxy-3,7-dimethyloct-6-enoic acid (1) and 3-hydroxy-2,2,3,7-tetramethyloct-6-enoic acid (2), were prepared from 6-methyl-5-hepten-2-one, and they were subsequently used to prepare (2,6,6-trimethyltetrahydropyran-2-ypacetic acid (3) and 2-methy1-2-(2,6,6-trimethyltetrahydropyran-2-yl)propanoic acid (4), respectively, via cyclization with an acidic catalyst such as boron trifluoride diethyl etherate or iodine. The reaction of carboxylic acids 3 and 4 with alcohols, including methanol, ethanol, and 1-propanol, produced the corresponding methyl, ethyl, and propyl esters, which all contained a tetrahydropyran ring. Reduction of carboxylic acids 3 and 4 afforded the corresponding alcohols. Subsequent reactions of these alcohols with several acyl chlorides produced novel esters. The alcohols also reacted with methyl iodide and sodium hydride to provide novel ethers. A one-pot cyclization esterification of 1 to produce esters containing a tetrahydropyran ring, using iodine as a catalyst, was also investigated.