Abstract  Genotoxic effects of a heavy metal, i.e. lead (Pb), on cyto-morphological parameters of chilli were investigated. Seeds were treated with five different concentrations (20, 40, 60, 80, 100ppm) of this heavy metal. The higher concentrations of lead nitrate significantly reduced plant height, pollen fertility and yield and caused variations in the plant at the seedling and mature stages. In addition, lead affected the pairing of homologous chromosomes and spindle formation: as the concentration of lead increases chromosomal abnormalities also significantly increase but chiasma frequency reduced. On the basis of these results, it was concluded that lower concentrations of metal did not significantly affect the cyto-morphology of Capsicum, while higher concentrations of lead nitrate were found to be more mutagenic and genotoxic.

Abstract  Marine actinomycetes have become sources of great interest to natural product chemistry due to their new chemical entities and bioactive metabolites. Since April 2010, we have screened actinobacteria from five sites that represent different ecosystems of Segara Anakan lagoon. In this present study we focus on specific isolates, K-2C which covers 1) actinomycetes identification based on morphology observation and 16S rRNA gene; 2) fermentation and isolation of pigment; 3) structure determination of pigment; and 4) hydrolytic enzymes characterization; Methodologies relevant to the studies were implemented accordingly. The results indicated that K-2C was likely Streptomyces fradiae strain RSU15, and the best fermentation medium should contain starch and casein with 21 days of incubation. The isolate has extracellular as well as intracellular pigments. Isolated pigments gave purple color with lambda(max) of 529.00 nm. The pigment was structurally characterized. Interestingly, Streptomyces K-2C was able to produce potential hydrolytic enzymes such as amylase, cellulase, protease, lipase, urease, and nitrate reductase.

Abstract  A facile new method for the synthesis of nanostructured Cu2O-ZnO and Cu2O-ZnO-MgO catalysts has been described. The catalysts were physically admixed with gamma-Al2O3 to form hybrid catalysts suitable for direct selective conversion of syngas to DME. The methanol synthesis component was synthesized from the corresponding nitrate precursors using Fehling's solution coupled with the glucose oxidation assisted precipitation method. This method resulted in the formation of the oxide form of the catalyst from the precursor phase and avoided ex situ calcination. In the present study, along with Cu2O, direct synthesis of divalent oxides (viz. ZnO and MgO) from their nitrate salts using Fehling's route has been demonstrated, which has resulted in highly structured Cu2O/ZnO/MgO catalysts. The resulting catalysts were characterized by XPS, XRD, BET-surface area, ammonia-TPD, H-2-TPR and SEM techniques. It was found that oxide phases were present in the catalyst. In addition, a different precursor phase with high purity and crystallinity along with high surface area, optimum acidity and lower reduction temperature was obtained through Fehling's method of catalyst synthesis. Catalytic activity for syngas conversion to DME was tested in the temperature range of 200-280 degrees C and the pressure range of 30-50 bar. The catalyst obtained through this method exhibited a syngas conversion of 50% and a DME selectivity of 80%. The catalyst is also found to be resistant towards coke formation as compared to the catalyst with a similar composition made through the conventional co-precipitation route.

Abstract  The monoclinic bismuth oxide was prepared by the solution combustion method using bismuthyl nitrate as the raw material and citric acid as fuel. The synthesis process consisted of the formation of a clear transparent solution and the formation of white powder after heating the mixture at 250 degrees C for 2 hours. The yellow pale crystalline materials were obtained after calcination of the white powder at 600 degrees C for 80 minutes. Furthermore, the photocatalytic activity of the product was also studied using methyl orange as a model pollutant. The result showed that the coral reef-like bismuth oxide was able to degrade 50 mL methyl orange (5 ppm) by 37.8 % within 12 hours irradiation using 75-watt tungsten lamp.

Abstract  Nitrite is a preservative agent broadly used in the food industry. Its excessive consumption can cause several diseases including cancer. Thus, the development of sensors for nitrite is indispensable for strict nitrite level control in industrialized products and consequently for human welfare. Herein, is presented a study of the modification of electrodes by electropolymerization of [Fe(Br-ph-tpy)(2)](PF6)(2) and its use as electroactive films in sensing of nitrite. The films were characterized by cyclic voltammetry, electrochemical quartz crystal microbalance, atomic-force microscopy and they were employed in electroanalytical experiments. The film obtained by electropolymerization exhibited some fibers dispersed on the substrate, reflecting the formation polymers on the surface of the electrode. The electrodes were further improved by drop casting a film of the complex on a glass carbon electrode, and then performing the electropolymerization of the complex. An increase in stability and a 41% enhancement of the electrocatalytical response for nitrite ions have been observed, in comparison with the bare electrode.

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Abstract  The aim of the study was to analyze and assess the possibility of using a two-stage filtration system with ceramic membranes: a 3-tube module with 1.0 kDa cut-off (1st stage) and a one-tube module with 0.45 kDa cut-off (2nd stage) for treating effluent water from a juvenile African catfish aquaculture. The study revealed that during the 1st filtration stage of the effluent water, the highest degrees of retention were obtained with respect to: suspended solids SS (rejection coefficient R-I = 100%), turbidity (R-I = 99.40%), total iron (R-I = 89.20%), BOD5 (R-I = 76.0%), nitrite nitrogen (R-I = 62.30%), and CODCr (R-I = 41.74%). The 2nd filtration stage resulted in a lower reduction degree of the tested indicators in comparison to the 1st filtration stage. At the 2nd stage, the highest values of the rejection coefficient were noted in for the total iron content (R-IV = 100%), CODCr (R-IV = 59.52%; R-V = 64.28%, R-VI = 63.49%) and turbidity (R-IV and R-V = 45.0%, R-VI = 50.0%). The obtained results indicate that ceramic membranes (with 1.0 and 0.45 kDa cut-offs) may be used in recirculation aquaculture systems as one of the stages of effluent water treatment.

Abstract  Nitramines are key constituents of most of the explosives currently in use and consequently contaminate soil and groundwater at many military facilities around the world. Toxicity from nitramine contamination poses a health risk to plants and animals. Thus, understanding how nitramines are biodegraded is critical to environmental remediation. The biodegradation of synthetic nitramine compounds such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has been studied for decades, but little is known about the catabolism of naturally produced nitramine compounds. In this study, we report the isolation of a soil bacterium, Variovorax sp. strain JS1663, that degrades N-nitroglycine (NNG), a naturally produced nitramine, and the key enzyme involved in its catabolism. Variovorax sp. JS1663 is a Gram-negative, non-spore-forming motile bacterium isolated from activated sludge based on its ability to use NNG as a sole growth substrate under aerobic conditions. A single gene (nnlA) encodes an iron-dependent enzyme that releases nitrite from NNG through a proposed β-elimination reaction. Bioinformatics analysis of the amino acid sequence of NNG lyase identified a PAS (Per-Arnt-Sim) domain. PAS domains can be associated with heme cofactors and function as signal sensors in signaling proteins. This is the first instance of a PAS domain present in a denitration enzyme. The NNG biodegradation pathway should provide the basis for the identification of other enzymes that cleave the N-N bond and facilitate the development of enzymes to cleave similar bonds in RDX, nitroguanidine, and other nitramine explosives.IMPORTANCE The production of antibiotics and other allelopathic chemicals is a major aspect of chemical ecology. The biodegradation of such chemicals can play an important ecological role in mitigating or eliminating the effects of such compounds. N-Nitroglycine (NNG) is produced by the Gram-positive filamentous soil bacterium Streptomyces noursei This study reports the isolation of a Gram-negative soil bacterium, Variovorax sp. strain JS1663, that is able to use NNG as a sole growth substrate. The proposed degradation pathway occurs via a β-elimination reaction that releases nitrite from NNG. The novel NNG lyase requires iron(II) for activity. The identification of a novel enzyme and catabolic pathway provides evidence of a substantial and underappreciated flux of the antibiotic in natural ecosystems. Understanding the NNG biodegradation pathway will help identify other enzymes that cleave the N-N bond and facilitate the development of enzymes to cleave similar bonds in synthetic nitramine explosives.

Abstract  This research proposed the real-time detection of nitrite by employing electrochemical impedance spectroscopy (EIS) technique incorporating an interdigital capacitive sensor. A self-assembled monolayer functionalized the sensing surface with embedded ion-imprinted polymer (IIP) with selectivity for nitrite ions were introduced. Syntheis and characterization of IIP are also explained to validate the polymerization technique. Some initial results using different concentrations of nitrite sample to validate the proposed method are also presented. The promising results highlight the extraordinary potential to develop low-cost, in-situ measurement system to detect nitrite contamination with real-time monitoring.

Abstract  A modified approach to synthesize and isolate arylnitromethanes is described. The method takes advantage of the significant difference in acidity between the arylnitromethane and the major impurity of the reaction, the nitrite ester. The arylnitromethanes resulting from this process are obtained in high yields and are analytically pure, i.e., they do not require distillation or further purification, which is a comfortable improvement of the ancestral Victor Meyer reaction. (C) 2016 Elsevier Ltd. All rights reserved.

Abstract  The peroxidative activity of horseradish peroxidase (HRP) undergoes progressive inactivation while catalyzing the oxidation of nitrite by H2O2. The extent of inactivation increases as the pH increases, [nitrite] decreases or [H2O2] increases, and is accompanied by a loss of the Soret peak of HRP along with yellow-greenish coloration of the solution. HRP-catalyzed nitrite oxidation by H2O2 involves not only the formation of compounds I and II as transient heme species, but also compound III, all of which in turn, oxidize nitrite yielding (•)NO2. The rate constant of nitrite oxidation by compound III is at least 10-fold higher than that by compound II, which is also reducible by (•)NO2 where its reduction by nitrite is the rate-determining step of the catalytic cycle. The extent of the loss of the Soret peak of HRP is lower than the loss of its peroxidative activity implying that deterioration of the heme moiety leading to iron release only partially contributes toward heme inactivation. Cyclic stable nitroxide radicals, such as 2,2,6,6-tetramethyl-piperidine-N-oxyl (TPO), 4-OH-TPO and 4-NH2-TPO at µM concentrations detoxify (•)NO2 thus protecting HRP against inactivation mediated by this radical. Hence, HRP inactivation proceeds via nitration of the porphyrin ring most probably through compound I reaction with (•)NO2, which partially leads to deterioration of the heme moiety. The nitroxide acts catalytically since its oxidation by (•)NO2 yields the respective oxoammonium cation, which is readily reduced back to the nitroxide by H2O2, superoxide ion radical, and nitrite. In addition, the nitroxide catalytically inhibits tyrosine nitration mediated by HRP/H2O2/nitrite reactions system as it efficiently competes with tyrosyl radical for (•)NO2. The inhibition by nitroxides of tyrosine nitration is demonstrated also in the case of microperoxidase (MP-11) and cytochrome c revealing an additional role played by nitroxide antioxidants.

Abstract  Zeolitic imidazolate framework-8 (ZIF-8) is one of easily available metal organic frameworks because of its facile preparation via mixing aqueous solutions of zinc nitrate and 2-methylimidazole. It turned into a very effective pH-responsive bactericide after loading with iodine. Approximately, 0.9g of iodine could be readily loaded into one gram of ZIF-8 from iodine dissolved n-heptane solution. Both Gram-negative Escherichia coli and Gram-positive Staphylococcus epidermidis and Staphylococcus aureus could be very effectively killed by iodine loaded ZIF-8 (ZIF-8@I) at pH6.0 within 3min. In contrast, at pH above 7.0, no appreciable antimicrobial activity could be detected. The bacteria killing effect is resulted from the iodine released from ZIF-8@I disintegrated at acidic pH. ZIF-8@I coated surface also showed its acidic pH-triggered antimicrobial activity against deposited bacterial cells. The antimicrobial activity of ZIF-8@I against actively grown bacterial lawns on a pH neutral agar plate was also observed. The result demonstrates that iodine was released from the disintegrated ZIF-8@I to kill bacteria in response to the bacterial growth-induced pH lowering.

Abstract  We report a new family of preorganized bis-lactam-1,10-phenanthroline (BLPhen) complexants that possess both hard and soft donor atoms within a convergent cavity and show unprecedented extraction strength for the trivalent f-block metal ions. BLPhen ligands with saturated and unsaturated δ-lactam rings have notable differences in their affinity and selectivity for Am(III) over Eu(III), with the latter being the most selective mixed N,O-donor extractant of Am(III) reported to date. Saturated BLPhen was crystallized with five Ln(III) nitrates to form charge-neutral 1:1 complexes in the solid state. DFT calculations further elaborate on the variety of effects that dictate the performance of these preorganized compounds.

Abstract  Synthesis of metallic and semiconductor nanoparticles through physical and chemical routes has been extensively reported. However, green synthesized metal nanoparticles are currently in the limelight due to the simplicity, cost-effectiveness and eco-friendliness of their synthesis. This study explored the use of aqueous leaf extract of Costus afer in the synthesis of silver nanoparticles (CA-AgNPs). The optical and structural properties of the resulting silver nanoparticles were studied using UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infra-red spectrophotometer (FTIR). TEM images of the silver nanoparticles confirmed the existence of monodispersed spherical nanoparticles with a mean size of 20 nm. The FTIR spectra affirmed the presence of phytochemicals from the Costus afer leaf extract on the surface of the silver nanoparticles. The electrochemical characterization of a CA-AgNPs/multiwalled carbon nanotubes (MWCNT)-modified electrode was carried out to confirm the charge transfer properties of the nanocomposites. The comparative study showed that the CA-AgNPs/MWCNT-modified electrode demonstrated faster charge transport behaviour. The anodic current density of the electrodes in Fe(CN)₆](4-)/[Fe(CN)₆](3-) redox probe follows the order: GCE/CA-Ag/MWCNT (550 mA/cm²) > GCE/MWCNT (270 mA/cm²) > GCE (80 mA/cm²) > GCE/CA-Ag (7.93 mA/cm²). The silver nanoparticles were evaluated for their antibacterial properties against Gram negative (Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa) and Gram positive (Bacillus subtilis and Staphylococcus aureus) pathogens. The nanoparticles exhibited better inhibition of the bacterial strains compared to the precursors (leaf extract of Costus afer and silver nitrate). Furthermore, the ability of the nanoparticles to scavenge DPPH radicals at different concentrations was studied using the DPPH radical scavenging assay and compared to that of the leaf extract and ascorbic acid. The nanoparticles were better DPPH scavengers compared to the leaf extract and their antioxidant properties compared favorably the antioxidant results of ascorbic acid. The green approach to nanoparticles synthesis carried out in this research work is simple, non-polluting, inexpensive and non-hazardous.

Abstract  RATIONALE: The molecular mechanisms that regulate tuberculosis susceptibility and bacillus Calmette-Guérin (BCG)-induced immunity are mostly unknown. However, induction of the adaptive immune response is a critical step in host control of Mycobacterium tuberculosis. Toll-interacting protein (TOLLIP) is a ubiquitin-binding protein that regulates innate immune responses, including Toll-like receptor signaling, which initiate adaptive immunity. TOLLIP variation is associated with susceptibility to tuberculosis, but the mechanism by which it regulates tuberculosis immunity is poorly understood.

OBJECTIVES: To identify functional TOLLIP variants and evaluate the role of TOLLIP variation on innate and adaptive immune responses to mycobacteria and susceptibility to tuberculosis.

METHODS: We used human cellular immunology approaches to characterize the role of a functional TOLLIP variant on monocyte mRNA expression and M. tuberculosis-induced monocyte immune functions. We also examined the association of TOLLIP variation with BCG-induced T-cell responses and susceptibility to latent tuberculosis infection.

MEASUREMENTS AND MAIN RESULTS: We identified a functional TOLLIP promoter region single-nucleotide polymorphism, rs5743854, which was associated with decreased TOLLIP mRNA expression in infant monocytes. After M. tuberculosis infection, TOLLIP-deficient monocytes demonstrated increased IL-6, increased nitrite, and decreased bacterial replication. The TOLLIP-deficiency G/G genotype was associated with decreased BCG-specific IL-2(+) CD4(+) T-cell frequency and proliferation. This genotype was also associated with increased susceptibility to latent tuberculosis infection.

CONCLUSIONS: TOLLIP deficiency is associated with decreased BCG-specific T-cell responses and increased susceptibility to tuberculosis. We hypothesize that the heightened antibacterial monocyte responses after vaccination of TOLLIP-deficient infants are responsible for decreased BCG-specific T-cell responses. Activating TOLLIP may provide a novel adjuvant strategy for BCG vaccination.

Abstract  An efficient, one step and genotype independent protocol of shoot organogenesis was developed from leaf and internodal explants taken from microshoots of different cultivars of potato (Solanum tuberosum L.). Initially, microshoots were cultured on basal Murashige and Skoog medium additionally supplemented with 10 µM AgNO3 (MS1 medium) to achieve healthy shoot growth required to get the quality explants. Shoot organogenesis was induced from both types of explants (leaf and internodal) on MS1 medium variously supplemented with 6-benzyladenine (BA) and gibberellic acid (GA3). Maximum explants were induced shoot organogenesis on MS1 medium supplemented with 10 µM BA and 15.0 µM GA3 from both the cultivars namely 'Kufri Chipsona 1' and 'Kufri Pukhraj'. Among the types of explants used, better response was observed from internodal segments as compared to leafs. This optimized medium combination was found to be equally effective for all the eight cultivars tested namely 'Kufri Pukhraj', 'Kufri Chipsona 1', 'Kufri Chipsona 2', 'Kufri Jyoti', 'Kufri Surya', 'Kufri Chandramukhi', 'Kufri Khyati' and 'Desiree'. The clonal uniformity of the regenerated shoots was confirmed using random amplified polymorphic DNA and inter-simple sequence repeats markers.

Abstract  In this work we present the structural, magnetic and surface characterization of the ceramic nickel manganite oxide NiMn2O4-delta synthesized by two methods: sol-gel and ultrasound-assisted sol-gel using nitrate salts as precursors. We have characterized the non-stoichiometric samples NiMn2O4-delta using different physicochemical analyses. X-ray diffraction and Rietveld refinement of the X-ray data indicated that the samples crystallize in the Fd3m space group characteristic of cubic spinel-related oxides. The specific surface area of the oxides was 1.3 m(2)/g (SG) and 16.3 m(2)/g (UASG). SEM results showed particle agglomerates of 1.05 mu m ( SG) and 0.85 mu m ( UASG). Temperature dependence magnetization measurements were performed and a ferrimagnetic transition was identified at 103 K and 105 K depending on the preparation method ( SG and UASG, respectively). The observed Curie constant was found to vary from 7.4 to 7.7 cm(3) K mol(-1) and hysteretic magnetization vs. applied field curves at different temperatures were obtained. XPS studies of these oxides reveal the presence of Ni2+, Mn2+, Mn3+ and Mn4+ ions at the surface. A probable ionic distribution as a function of the synthesis method is proposed. (C) 2016 Elsevier B.V. All rights reserved.

Abstract  A method for the determination of nitrite in soil and vegetable samples by UV-Vis spectroscopy was proposed. The kinetic UV-Vis data were collected during the reaction between nitrite and 4-amino-3-hydroxynaphthalene-1-sulfonic acid with concentration of 0.001 M and pH 1.6. Data were collected by standard addition method. Multivariate curve resolution-alternating least squares was employed to analyze data with non-negativity and three-way data structure constraints. The method can be used to solve matrix effect and unknown interferents in the determination of nitrite in complex samples. The proposed method was used to determine nitrite at low mg/L levels with satisfactory results in soil, lettuce, cabbage and cucumber samples.

Abstract  As a visible light active p-type semiconductor, CuBi2O4 is of interest as a photocatalyst for the generation of hydrogen fuel from water. Here we present the first photovoltage and photocatalytic measurements on this material and DFT results on its band structure. Single crystalline CuBi2O4 nanoparticles (25.7 +/- 4.7 nm) were synthesized from bismuth and cupric nitrate in water under hydrothermal conditions. Powder X-ray diffraction (XRD) confirms the CuBi2O4 structure type and UV-Vis spectroscopy shows a 1.75 eV optical band gap. Surface photovoltage (SPV) measurements on CuBi2O4 nanoparticle films on fluorine doped tin oxide yield 0.225 V positive photovoltage at > 1.75 eV photon energy confirming holes as majority carriers. The photovoltage is reversible and limited by light absorption. When dispersed in 0.075 M aqueous potassium iodide solution, the CuBi2O4 particles support photochemical hydrogen evolution of up to 16 mu mol h(-1) under ultraviolet but not under visible light. Based on electrochemical scans, CuBi2O4 is unstable toward reduction at -0.2 V, but a pH-dependent photocurrent of 6.45 mu A cm(-2) with an onset potential of +0.75 V vs. NHE can be obtained with 0.01 M Na2S2O8 as a sacrificial electron acceptor. The photoelectrochemical properties of CuBi2O4 can be explained on the basis of the band structure of the material. DFT calculations show that the valence and conduction band edges arise primarily from the combination of O 2p and Cu 3d orbitals, respectively, with additional contributions from Cu 3d and Bi 6s orbitals just below the Fermi level. Trapping of photoelectrons in the Cu 3d band is the cause for reductive photocorrosion of the material, while the p-type conductivity arises from copper vacancy states near the VB edge. These findings provide an improved understanding of the photophysical properties of p-CuBi2O4 and its limitations as a proton reduction photocatalyst.

Abstract  In our continuing search for more potent anticancer agent, eight novel nitrates couple with C-10 colchicine nitric oxide-releasing derivatives (5a-f and 7a-b) were prepared. These target compounds were assayed for their anti-tumor activity in vitro against four cancer cell lines, including human hepatocellular carcinoma cells (BEL7402), human ovary carcinoma cells (A2780), human lung adenocarcinoma cells (A549) and human breast carcinoma cells (MCF7). Preliminary results indicated that most of them exhibited significant cytotoxic effect toward cancer cells. Compound 7a was investigated further for its more potent cytotoxicity than colchicine.

Abstract  Maize genotypes vary significantly in their nitrogen use efficiencies (NUEs). Better understanding of early grain filling characteristics of maize is important, especially for maize with different NUEs. The objectives of this research were (i) to investigate the difference in apical kernel development of maize with different NUEs, (ii) to determine the reaction of apical kernel development to N application levels, and (iii) to evaluate the relationship between apical kernel development and grain yield (GY) for different genotypes of maize. Three maize hybrid varieties with different NUEs were cultivated in a field with different levels of N fertilizer arranged during two growing seasons. Kernel fresh weight (KFW), volume,(KV) and dry weight (KDW) of apical kernel were evaluated at an early grain filling stage. Ear characteristics, GY and its components were determined at maturity stage. Apical kernel of the high N and high efficiency (HN-HE) type (under low N, the yield is lower, and under higher N, the yield is higher) developed better under high N (N210 and N240, pure N of 210 and 240 kg ha(-1)) than at low N (N120 and N140, pure N of 120 and 140 kg ha(-1)). The low N and high efficiency (LN-HE) type (under low N, the yield is higher, while under higher N, the yield is not significantly higher) developed better under low N than at high N. The double high efficiency (D-HE) type (for both low and high N, the yield is higher) performed well under both high and low N. Apical kernel reacted differently to the N supply. Apical kernel developed well at an early grain filling stage and resulted in a higher kernel number (KN), kernel weight (KW) and GY with better ear characteristics at maturity.

Abstract  A new series of cobalt-free perovskite-type oxides, Nd0.5Ba0.5Fe1-xNixO3-delta (0 <= x <= 0.15), have been prepared by a citric acid-nitrate process and investigated as cathode materials for proton conducting intermediate temperature solid oxide fuel cells (IT-SOFCs). The conductivity of the oxides was measured at 300-800 degrees C in air. It is discovered that partial substitution of Ni for Fe-sites in Nd0.5Ba0.5Fe1-xNixO3-delta obviously enhances the conductivity of the oxides. Among the series of oxides, the Nd0.5Ba0.5Fe0.9Ni0.1O3-delta (NBFNi10) exhibits the highest conductivity of 140 S cm(-1) in air at 550 degrees C. A single H-2/air fuel cell with proton-conducting BaZr0.1Ce0.7Y0.2O3-delta (BZCY) electrolyte membrane (ca. 40 mu m thickness) and NBFNi10-BZCY composite cathode and NiO-BZCY composite anode was fabricated and tested at 600-700 degrees C. The peak power density and the interfacial polarization resistance (R-p) of the cell are 490 mW cm(-2) and 0.15 W cm(2) at 700 degrees C, respectively. The experimental results indicate that NBFNi10 is a promising cathode material for the proton-conducting IT-SOFCs.

Abstract  Copper oxides (CuOx) nanoparticles dispersed on activated carbon (AC) were prepared by using vapor phase methanol as the reducing agent. The CuOx/AC as prepared exhibited an enhanced catalytic activity in oxidative carbonylation of methanol to dimethyl carbonate (DMC). The catalytic performance was significantly influenced by reduction conditions including temperature and time. With the similar selectivity of DMC, the space time yield (STY) under optimal reduction conditions reached up to 408 mg g(-1) h(-1), which is superior to conventional methods such as thermolysis and solvothermal reduction. Based on the characterization results of XRD, TEM and XPS, the good copper dispersion and high Cu+ content obtained by vapor-phase methanol reduction were mainly responsible for the high catalytic activity. (C) 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Abstract  A series of composites comprised of graphene (rGO) and carbon nanotube (CNT) with various weight ratios of them have been synthesized. The catalytic performance of the Pt catalysts supported on the rGO CNT composites has been evaluated in the dehydrogenation of liquid organic hydride (decalin) for hydrogen releasing and compared with that of Pt/rGO and Pt/CNT catalysts. Both microwave irradiation and conventional heating methods have been adopted for the reaction. The structural and surficial features of the composites and rGO as well as CNT have been characterized by means of several techniques. The thermal behaviour of different carbon materials under microwave irradiation has been measured. The results show that there is an optimal CNT weight content in the composites leading the Pt/rGO-CNT0.17 catalyst to the best performance that cannot be achieved by the other catalysts including Pt/rGO and Pt/CNT as well. This has been ascribed to the most plentiful interface formed between rGO and CNT of a proper content, which is beneficial to the deposition of the Pt nanoparticles having the highest catalytic activity. Additionally, the strong coupling effect of carbon materials with microwave irradiation gives rise to better catalytic performance in comparison to conventional heating due to its capability to induce higher reaction temperatures. Nevertheless, the intrinsic catalytic properties of the Pt catalysts supported on different carbon materials are independent on the heating modes. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Abstract  Hydrothermal reaction of Ln nitrate and Na2WO4 at pH=8 and 200 degrees C for 24 hours, in the absence of any additive, has directly produced the scheelite-type sodium lanthanide tungstate of NaLn(WO4)(2) for the larger Ln(3+) of Ln=La-Dy (including Y, Group I) and an unknown compound that can be transformed into NaLn(WO4)(2) by calcination at the low temperature of 600 degrees C for the smaller Ln(3+) of Ln= Ho-Lu (Group II). With the successful synthesis of NaLn(WO4)(2) for the full spectrum of Ln, the effects of lanthanide contraction on the structural features, crystal morphology, and IR responses of the compounds were clarified. The temperature-and timecourse phase/morphology evolutions and the phase conversion upon calcination were thoroughly studied for the Group I and Group II compounds with Ln=La and Lu for example, respectively. Unknown intermediates were characterized by elemental analysis, IR absorption, thermogravimetry, and differential scanning calorimetry to better understand their chemical composition and coordination. The photoluminescence properties of NaEu(WO4)(2) and NaTb(WO4)(2), including excitation, emission, fluorescence decay, and quantum efficiency of luminescence, were also comparatively studied for the as-synthesized and calcination products.

Abstract  Phase-pure (Y1-xEux)(2)WO6 (x = 0.2-0.11) red phosphors (average crystallite size similar to 66 nm) in a monoclinic structure have been calcined at 1300 degrees C from their precursors autoclaved from the mixed solutions of rare-earth nitrate and sodium tungstate dihydrate (Na2WO4.2H(2)O) at 180 degrees C and pH similar to 10, instead of the commonly adopted pH values of 3-7, without the use of any surfactant. The materials were characterized in detail by the combined techniques of XRD, FT-IR, FE-SEM, TEM, EDS, and optical spectroscopy to reveal (1) the phase structure, morphology, and spatial cation distribution of the hydrothermal product, (2) the course of phase and morphology evolution that leads to the targeted tungstate phosphor, and (3) the effects of Eu3+ content on photoluminescence properties, including excitation/emission, asymmetry factor of luminescence (D-5(0) -> F-7(2)/D-5(0) -> F-7(1) intensity ratio), fluorescence lifetime, and CIE chromaticity coordinates. Through energy transfer from the [WO6](6-) ligands to Eu3+, the (Y1-xEux)(2)WO6 phosphors exhibit sharp (D0 -> FJ)-D-5-F-7 (J = 0-4) emissions upon UV excitation into the O2--W6+ charge transfer band peaked at 327 nm, with the red emission at 611 nm being the most prominent (D-5(0)-> F-7(2) transition of Eu3+). The optimal Eu3+ content was determined to be similar to 9 at.% (x = 0.09), and concentration quenching of luminescence was analyzed to be owing to exchange interaction. The emission color moves closer to the red region in the CIE chromaticity diagram with increasing Eu3+ doping, while fluorescence lifetime of the 611 nm emission, analyzed to be around 1.05 +/- 0.05 ms, shows weak dependence on the Eu3+ content. (C) 2016 Elsevier B.V. All rights reserved.