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In this work, the procedure for the in situ-forming process of Al2O3-SiO2-based foams slurry using diacetin (DAT) and silica sol (SS) as the gelling agents was evaluated, and the rheological behavior of the foam slurry was studied. The results showed that the rheological properties played a key role during the curing process of foam slurry. Excellent thixotropy, obvious pseudoplasticity, and large critical strain for the gelling agent contained foam slurries meant a stronger internal three-dimensional network structure which was conducive to shorten the curing time of the foam slurry for further applications. With this technique, we were able to produce porous mullite ceramics with good mechanical and structural properties. After sintering the as-prepared green body at 1350 °C, the porous ceramics were found with a bulk density of 0.528 g/cm³, a compressive strength of 2.49 MPa, an apparent porosity of 77.9%, and pores ranging from 100 to 500 μm. [ABSTRACT FROM AUTHOR]

Microbial polyphosphate (polyP) production is vital to the removal of phosphate from wastewater. However, to date, engineered polyP synthesis using genetically accessible environmental bacteria remains a challenge. This study develops a simple solo medium-copy plasmid-based polyphosphate kinase (PPK1) overexpression strategy for achieving maximum intracellular polyphosphate accumulation by environmental bacteria. The polyP content of the subsequently engineered Citrobacter freundii (CPP) could reach as high as 12.7% of its dry weight. The biomass yield of CPP was also guaranteed because of negligible metabolic burden effects resulting from the medium plasmid copy number. Consequently, substantial removal of phosphate (Pi) from the ambient environment was achieved simultaneously. Because of the need for exogenous Pi for in vivo ATP regeneration, CPP could thoroughly remove Pi from synthetic municipal wastewater when it was applied for the "one-step" removal of Pi with a bench-scale sequence batch membrane reactor. Almost all the phosphorus except for that assimilated by CPP for cellular growth could be recovered in the form of more concentrated Pi. Overall, engineering environmental bacteria to overexpress PPK1 via a solo medium-copy plasmid strategy may represent a valuable general option for not only biotechnological research based on sufficient intracellular polyP production but also removal of Pi from wastewater and Pi enrichment. [ABSTRACT FROM AUTHOR]

Adhesion at the dissimilar interface of single wall carbon nanotube (SWCNT) bundles and electrospun polymer nanofibers (Espun) was directly measured using a nano cheese cutter. A sample fiber suspended at the tip of an atomic force microscope cantilever and another freestanding fiber on a mica substrate were arranged in a cross-cylinder configuration and allowed to adhere. External tensile load led to spontaneous detachment or "pull-off". Adhesion was shown to be dominated by van der Waals attraction, and the detachment process conforms to the classical Maugis parameter in the JKR-DMT transition. [ABSTRACT FROM AUTHOR]

The grain structure of ordered block copolymer materials affects their viscoelastic, adhesive, optical, and electrical properties. Depolarized light scattering has proven to be an important method for characterizing this grain structure. In this paper, we use both theory and experiments to demonstrate the relationship between grain structure and depolarized light scattering from ordered block copolymer samples performed with crossed circular polarizers. We model the sample assuming it comprises randomly oriented ellipsoidal grains with optic axes coincident with the ellipsoid axes. We show that the scattering pattern obtained using circularly polarized (CP) light is azimuthally symmetric, in contrast to that obtained using linearly polarized (LP) light which exhibits 4-fold angular modulation. The integrated scattered power in the CP case is twice as large as that in the LP case. By simultaneously fitting CP and LP light scattering data, we obtain robust measures of parameters that characterize grain structures. In addition, CP light scattering can, in principle, be used to characterize nonrandom grain orientation distributions. [ABSTRACT FROM AUTHOR]

Phosphorylated graphene oxides (PGO) were synthesized by a one-pot method and fabricated on the surface of cotton fabrics for the improvement of fire safety. The chemical structure of PGO was characterized by FTIR and XPS. SEM images of the pure and coated cotton fabrics indicated that PGO had better compatibility with water than GO and was more beneficial for self-assembly fabrication than GO. Vertical flame test and cone calorimeter test revealed that flame retardancy of cotton fabrics was obviously improved by PGO based multilayer coating. The plausible flame retardancy mechanism was proposed: PGO with large layered structures could effectively insulate the permeation of oxygen and volatile flammable gases, thereby decreasing the heat release rate; on the other hand, the presence of phosphorus could play an important role in the catalytic charring effect during combustion, which significantly promoted the formation of char residue and then further prevented the permeation of oxygen and pyrolysis products. [ABSTRACT FROM AUTHOR]

The first total syntheses of Lycopodium alkaloids palhinine A, palhinine D, and their C3-epimers have been divergently achieved through the use of a connective transform to access a pivotal hexacyclic isoxazolidine precursor. A microwave-assisted regio- and stereoselective intramolecular nitrone-alkene cycloaddition was tactically orchestrated as a key step to install the crucial 10-oxa-1-azabicyclo[5.2.1]decane moiety embedded in the conformationally rigid isotwistane framework, demonstrating the feasibility of constructing the highly strained medium-sized ring by introduction of an oxygen bridging linker to relieve the transannular strain in the polycyclic scaffold. Subsequent N-O bond cleavage provided the synthetically challenging nine-membered azonane ring system bearing the requisite C3 hydroxyl group. Late-stage transformations featuring a chemo- and stereoselective reduction of the pentacyclic β-diketone secured the availability of our target molecules. [ABSTRACT FROM AUTHOR]

Natural organic matter (NOM) represents the major source of precursors for disinfection byproducts (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs), formed during disinfection of drinking water, but the molecular composition and reactivity of NOM remain not well understood. In this study, electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize the molecular composition of NOM of 20 source waters taken across China for the purpose of determining the major precursors of THMs and HAAs at molecular level. It was found that there is a core of NOM compositions that are ubiquitous in different source waters, which is supposed to be more relevant for NOM quality. Formation potentials (FP) of THMs and HAAs were determined for NOM from different source waters during chlorination. Spearman's rank correlation was used to link THMFP and HAAFP with the individual molecular composition of NOM. Significant correlation (P < 0.001) was found between DBPFP and the NOM molecules with a high O/C ratio and low H/C ratio, indicating these molecules could contribute greatly to the formation of THMs and HAAs during chlorination. The link of THMFP and HAAFP with individual NOM molecules may allow us to develop more effective treatment strategies to achieve the drinking water safety objective: effective disinfection of waterborne pathogens while minimizing toxic DBPs. [ABSTRACT FROM AUTHOR]

Block copolymer/lithium salt mixtures are an emerging class of lithium battery electrolytes. Previous studies have shown that the ionic conductivity of these materials is a sensitive function of grain size. Both depolarized light scattering (DPLS) and small-angle X-ray scattering (SAXS) have proven to be effective techniques for elucidating the grain structure of block copolymer (BCP) materials. DPLS is particularly useful for the characterization of samples with grain sizes larger than 1 μm, whereas SAXS is particularly well suited for samples with grain sizes smaller than 0.1 μm. We present the results of both DPLS and SAXS measurements of grain structure in a BCP/lithium salt mixture that was annealed after being initially prepared by freeze-drying from solution. The combination of the two techniques demonstrates that our sample is characterized by an extremely wide distribution of grain sizes. In particular, the sample has a large population of small sub-micrometer-sized grains that cannot be detected optically. A bimodal grain distribution model is presented to support this interpretation of the experimental data. The presence of both large grains and regions of undetectable small grains was confirmed by polarized optical microscopy (POM). Two-wavelength DPLS measurements provide an additional approach for characterizing block copolymer samples with a broad distribution of grain sizes. [ABSTRACT FROM AUTHOR]

Alternating current (AC) is known to inactivate microbial growth in suspension, but how AC influences anaerobic biofilm activities has not been systematically investigated. Using a Geobacter dominated anaerobic biofilm growing on the electrodes of microbial electrochemical reactors, we found that high frequency AC ranging from 1 MHz to 1 kHz (amplitude of 5 V, 30 min) showed only temporary inhibition to the biofilm activity. However, lower frequency (100 Hz, 1.2 or 5 V) treatment led to 47 ± 19% permanent decrease in limiting current on the same biofilm, which is attributed to the action of electrohydrodynamic force that caused biofilm damage and loss of intercellular electron transfer network Confocal microscopy images show such inactivation mainly occurred at the interface between the biofilm and the electrode. Reducing the frequency further to 1 Hz led to water electrolysis, which generated gas bubbles that flushed all attached cells out of the electrode. These findings provide new references on understanding and regulating biofilm growth, which has broader implications in biofouling control, anaerobic waste treatment, energy and product recovery, and general understanding of microbial ecology and physiology. [ABSTRACT FROM AUTHOR]

A metal-free method for synthesis of N-(2-hydroxyaryl)benzotriazoles via O-arylation of N-hydroxybenzotriazoles with readily available diaryliodonium salts and sequential N-O bond cleavage under mild conditions has been developed. The [3,3]-rearrangement of N-O bond cleavage could take place on the N instead of C atom. The reaction was compatible with diverse functional groups and a new type of P,N-ligand was synthesized in three steps. [ABSTRACT FROM AUTHOR]

Solubility of inorganic salts in the mixed systems containing surfactants and sodium tripolyphosphate (STPP) is very important for the production of laundry detergents. In this work we explored the solubility of NaCl, Na2SO4, and Na2CO3 in aqueous surfactant and STPP solutions using an ion selective electrode at 298.15 K. In the experiments, electromotive forces (EMF) for the ternary systems were measured using an ion-meter with a sodium ion-selective composite electrode and the relationship between the solubility and EMF was analyzed by a potentiometric analysis. The proposed method has advantages in avoiding the solid-liquid separation operation and solution supersaturation. The experimental results indicated that the salting-out effect caused by surfactant and STPP can decrease the solubility of sodium salts in the aqueous systems. [ABSTRACT FROM AUTHOR]

The influence of the supramolecular interaction type--hydrogen bonding, proton transfer, and pure ionic bonding--on photoresponsive behavior, particularly surface relief grating (SRG) inscription, has been investigated using a homopolymer with an ambient temperature glass transition (Tg). To this end, poly(dimethylaminoethyl methacrylate) (PDMAEMA or PDM) of relatively high molecular weight (42K) was complexed at various azo/DM molar ratios with dimethylaminoazobenzene derivatives functionalized by hydroxyl (azoOH) or carboxylic acid (p-methyl red or azoCOOH) groups, and quaternized PDM (PDMQ) was complexed at equimolar ratio with a sulfonated analogue (methyl orange or azoSO3), and the structural and thermal properties of these complexes were determined. SRG inscription on spin-coated films was found to be possible because complexation increases the Tg above ambient. The efficiency of SRG inscription on spin-coated films, which increases with azo content, is highest for the purely ionic azoSO3/PDMQ complex despite its very high Tg, while the proton transfer azoCOOH/PDM complexes, involving ionic and H-bonding with acid-salt structures, show somewhat more efficient SRG inscription than do the purely hydrogen-bonded azoOH/PDM complexes, and this despite some azoCOOH crystallization at the highest molar ratios. These findings clarify the comparative effectiveness of different supramolecular bond types on SRG inscription and provide a useful guide for the design of supramolecular photoresponsive polymers for SRG applications. [ABSTRACT FROM AUTHOR]

Lipid tilt affects the energy of membrane deformations on scales comparable to the membrane's thickness. The surface divergence of the tilt field creates a local spontaneous curvature, while tilt itself is quadratically penalized with a strength given by the tilt modulus. Traditionally, this modulus is determined by measuring the power spectrum of lipid orientation fluctuations. Here we present a novel approach which does not rely on fluctuations but instead exploits the fact that curvature gradients induce a tilt field. Its implementation extends a technique previously developed by us for localizing the position of the pivotal plane in buckling simulations, which quantifies the lipid imbalance across segments cut out from a complete buckle. Lipid tilt affects this count in a predictable way, and the signal can be quantified well enough to back out the tilt modulus-at no additional cost and with about 5% precision for not too coarse models. We apply our technique to three lipid models of very different resolution: the highly coarse grained Cooke model, and two versions of DMPC, using both the (less highly coarse grained) MARTINI and the (united atom) Berger force field. For Cooke, we find an effective bilayer tilt modulus of 29 ± 9 pN/nm, and for the less generic DMPC lipid, we find 115 ± 6 pN/nm for MARTINI and 39 ± 2 pN/nm for Berger, both in reasonable agreement with existing studies for these models. We also show that the position of the pivotal plane for Berger DMPC lies just below the glycerol backbone-unlike for MARTINI DMPC, where this plane lies closer to the middle of the lipid. [ABSTRACT FROM AUTHOR]

Layered double hydroxide (LDH) is regarded as a prominent flame-retardant nanoadditive for polymers. However, the flame-retardant efficiency of a LDH depends strongly on its dispersion state and composition. Usually, modification or functionalization of a LDH is crucial to obtaining high-performance polymer nanocomposites. In order to develop multifunctional epoxy nanocomposites, in this study a LDH was first modified by biobased flame-retardant species, phytic acid (Ph) and (hydroxypropyl)sulfobutyl-β-cyclodextrin sodium (CDBS), and subsequently decorated by Fe3O4 nanoparticles to obtain a Fe3O4 nanosphere@LDH hybrid. Results obtained from size distribution and transmission electron microscopy revealed that the Fe3O4 nanoparticles with an average size of 8 nm were well decorated on the LDH platelet. The Fe3O4-decorated LDH hybrids facilitated their dispersion within an epoxy matrix, as indicated in X-ray diffraction. The incorporation of an as-prepared Fe3O4@Ph-CDBS-LDH hybrid into epoxy resin (EP) not only improved the flame-retardant properties but also endowed EP with increased thermal conductivity. Specifically, the peak heat release rate and total smoke production of the EP composite with 8 wt % Fe3O4@Ph-CDBS-LDH were decreased by 55% and 34%, respectively, in comparison to those of pristine EP, and the UL-94 V0 rating requirement can be met. The investigation provides a promising approach for the preparation of multifunctional LDH hybrids and related high-performance polymer nanocomposites by just using a functionalized nanomaterial. [ABSTRACT FROM AUTHOR]

Silksare widely used biomaterials, but there are still weaknessesin their mechanical properties. Here we report a method for improvingthe silk fiber mechanical properties by genetic disruption of theionic environment for silk fiber formation. An anterior silk gland(ASG) specific promoter was identified and used for overexpressingion-transporting protein in the ASG of silkworm. After isolation ofthe transgenic silkworms, we found that the metal ion content, conformationand mechanical properties of transgenic silk fibers changed accordingly.Notably, overexpressing endoplasmic reticulum Ca2+-ATPasein ASG decreased the calcium content of silks. As a consequence, silkfibers had more α-helix and β-sheet conformations, andtheir tenacity and extension increased significantly. These findingsrepresent the in vivo demonstration of a correlation between metalion content in the spinning duct and the mechanical properties ofsilk fibers, thus providing a novel method for modifying silk fiberproperties. [ABSTRACT FROM AUTHOR]

Toxicological studies have shown that phthalates, a class of widely used chemicals, can impair male reproductive function, but epidemiological evidence is in consistent This study aimed to investigate the associations of semen phthalate metabolites with sperm apoptosis and DNA damage in a Chinese population. We assessed sperm apoptosis markers with Annexin V/PI analysis and sperm DNA integrity with comet assay before measuring eight phthalate metabolites in semen by high-performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS ) among 463 men from Wuhan, China. We found a suggestive do se-response relationship between semen mono-(2-ethylhexyl) phthalate (MEHP) and an increased percentage of Annexin V7PF sperm (p for trend of <0.10). We also observed that semen monomethyl phthalate (MMP) and monoethyl phthalate (MEP) were associated with significant dose-related increases in tail length of the comet (both p for trend of < 0.01). In conclusion, our data indicate that semen MEHP is associated with increased sperm apoptosis and that semen MMP and MEP are associated with increased sperm DNA damage in a Chinese population. [ABSTRACT FROM AUTHOR]

Inrecent DNA microarray studies, we found that the transcription ofthe Id3gene was significantly down-regulated infive cell lines (RAW264.7, Hepa1–6, THP-1, HepG2, and HL7702)treated with two doses (50 and 100 μg/mL) of a DMSA-coated magnetitenanoparticle. Given the regulatory roles of Idgenesin the cell cycle, growth, and differentiation, we wanted to do moreinvestigations on the effect of the nanoparticle upon the Idgenes. This study detected the expression of Idgenes in six cell lines (the above cell lines plus HeLa)treated with the nanoparticle at the same doses using quantitativePCR. The results revealed that the expression of Idgenes was significantly affected by the nanoparticle in these celllines. Under each treatment, the Id3gene was significantly(p< 0.01) down-regulated in all cell lines, the Id1gene was significantly down-regulated in all cell linesexcept the RAW264.7 cells, and the Id2gene was significantlydown-regulated in the HepG2, HL7702, and HeLa cells. Because the Id1, Id2, and Id3geneswere significantly down-regulated in three liver-derived cell lines(Hepa1–6, HepG2, and HL7702) in both microarray and PCR detections,this study then detected the expression of Idgenesin the liver tissues of mice that were intravenously injected withthe nanoparticle at two doses (2 and 5 mg/kg body weight). The resultsrevealed that the expression of Id1, Id2, and Id3genes was also significantly down-regulatedin the liver tissues under each treatment. Another Idgene, Id4, was also significantly regulated insome cells or liver tissues treated with the nanoparticle. These resultsreveal that the nanoparticle exerts a significant effect on the in vitroand in vivoexpression of Idgenes. This study thus provides new insights into the Id-related nanotoxicity of the nanoparticle and the closerelationship between the regulation of Idgenes andiron. [ABSTRACT FROM AUTHOR]

Short interfering RNAs (siRNAs) are broadly used to manipulate gene expression in mammalian cells. Although chemical modification is useful for increasing the potency of siRNAs in vivo, rational optimization of siRNA performance through chemical modification is still a challenge. In this work, we designed and synthesized a set of siRNAs containing modified two-nucleotide 3'-overhangs with the aim of strengthening the interaction between the 3'-end of the siRNA strand and the PAZ domain of Ago2. Their efficiency of binding to the PAZ domain was calculated using a computer modeling program, followed by measurement of RNA–Ago2 interaction in a surface plasmon resonance biochemical assay. The results suggest that increasing the level of binding of the 3'-end of the guiding strand with the PAZ domain, and/or reducing the level of binding of the sense strand through modifying the two-nucleotide 3'-overhangs, affects preferential strand selection and improves siRNA activity, while we cannot exclude the possibility that the modifications at the 3'-end of the sense strand may also affect the recognition of the 5'-end of the guiding strand by the MID domain. Taken together, our work presents a strategy for optimizing siRNA performance through asymmetric chemical modification of 3'-overhangs and also helps to develop the computer modeling method for rational siRNA design. [ABSTRACT FROM AUTHOR]

Online coupling of in-tube solid phase micro-extraction (IT-SPME) with direct analysis in real time mass spectrometry (DART-MS) was realized for the first time and applied in the analysis of triazine herbicides in lake water and orange juice. We incorporated single-wall carbon nanotubes (SWNTs) into a polymer monolith containing methacrylic acid (MAA) and ethylene dimethacrylate (EDMA) to form a novel poly(mefhacrylic add-co-ethylene dimethacrylate-co-single wall carbon nanotubes) (poly(MAA-EDMA-SWNT)) monolith, which was then used in IT-SPME for enrichment of six triazine herbicides from water samples. With the online combination of IT-SPME with DART-MS, the analytes desorbed from the monolith were directly ionized by DART and transferred into MS for detection, thus rapid determination was achieved. Compared with regular DART-MS method, this online IT- SPME-DART-MS method was more sensitive and reproducible, because of the IT-SPME procedures and the isotope-labeled internal standard used in the experiment. Six triazine herbicides were determined simultaneously using this method with good linearity (R2 > 0.998). The limit of quantification (signal-to-noise ratio of S/N = 10) of the six herbicides were only 0.06-0.46 ng/mL. The proposed method has been applied to determine triazine herbicides in lake water and orange juice, showing satisfactory recovery (85%-106%) and reproducibility (relative standard deviation of RSD = 3.1%-10.9%). [ABSTRACT FROM AUTHOR]

Activated carbon (AC) is a promising catalyst for the air cathode of microbial fuel cells (MFCs) because of its high performance and low cost. To increase the performance of AC air cathodes, the acceleration of OH- transport is one of the most important methods, but it has not been widely investigated. Here we added quaternary ammonium to ACs by in situ anchoring of a quaternary ammonium/epoxide-reacting compound (QAE) or ex situ mixing with anion exchange resins in order to modify ACs from not only the external surface but also inside the pores. In 50 mM phosphate buffer solution (PBS), the in situ anchoring of QAE was a more effective way to increase the power. The highest power density of 2781 ± 36 mW/m2, which is 10% higher than that of the control, was obtained using QAE-anchored AC cathodes. When the medium was switched to an unbuffered NaCl solution, the increase in maximum power density (885 ± 25 mW/m2) was in accordance with the anion exchange capacity (0.219 mmol/g). The highest power density of the anion exchange resin-mixed air cathode was 51% higher than that of the control, indicating that anion exchange is urgently needed in real wastewaters. Excess anchoring of QAE blocked both the mesopores and micropores, causing the power output to be inhibited. [ABSTRACT FROM AUTHOR]

In this study, we employed AFM analysis combined with mathematical modeling for quantifying cell-surface contact mechanics and magnitude and range of cell-surface interaction forces for seven bacterial strains with a wide range of cell morphology, dimension, and surface characteristics. Comprehensive cell-surface characterization including surface charge, extracellular polymeric substance content, hydrophobicity, and cell-cell aggregation analyses were performed. Flow-through column tests were employed to determine the attachment efficiency and deposition-transport behavior of these bacterial strains. No statistically significant correlation between attachment efficiency and any single-cell surface property was identified. Single-cell characterization by atomic force microscopy (AFM) yielded the mechanical deformation and elastic modulus, penetration resistance to AFM probe penetration by cellular surface substances (CSS), range and magnitude of the repulsive-attractive intersurface forces, and geometry of each strain. We proposed and derived a universal dimensionless modified Tabor's parameter to integrate all these properties that account for their collective behavior. Results showed that the Tabor parameter derived from AFM analysis correlated well with experimentally determined attachment efficiency (α), which therefore is able to link microscale cell-surface properties with macroscale bacterial transport behavior. Results suggested that the AFM tests performed between a single cell and a surface captured the key quantities of the interactions between the cell and the surface that dictate overall cell attachment behavior. Tabor's parameter therefore can be potentially incorporated into the microbial transport model. [ABSTRACT FROM AUTHOR]

Photoswitch-modified DNA is being studied for applications including light-harvesting molecular motors, photocontrolled drug delivery, gene regulation, and optically mediated assembly of plasmonic metal nanoparticles in DNA- hybridization assays. We study the sequence and hybridization dependence of the photoisomerization quantum yield of azobenzene attached to DNA via the popular d-threoninol linkage. Compared to free azobenzene we find that the quantum yield for photoisomerization from trans to cis form is decreased 3-fold (from 0.094 ± 0.004 to 0.036 ± 0.002) when the azobenzene is incorporated into ssDNA, and is further reduced 15-fold (to 0.0056 ± 0.0008) for azobenzene incorporated into dsDNA. In addition, we find that the quantum yield is sensitive to the local sequence including both specific mismatches and the overall sequence-dependent melting temperature (Tm). These results serve as design rules for efficient photoswitchable DNA sequences tailored for sensing, drug delivery, and energy-harvesting applications, while also providing a foundation for understanding phenomena such as photonically controlled hybridization stringency. [ABSTRACT FROM AUTHOR]

Sensitive detection of DNA usually relies on target amplification approaches such as polymerase chain reaction and rolling circle amplification. Here we describe a new approach for sensitive detection of low-abundance DNA using liposome-quantum dot (QD) complexes and single-particle detection techniques. This assay allows for detection of single-stranded DNA at attomolar concentrations without the involvement of target amplification. Importantly, this strategy can be employed for simultaneous detection of multiple DNA targets. [ABSTRACT FROM AUTHOR]

Microbes play an important role in arsenic transformation and cycling in the environment. Microbial arsenic oxidation and reduction were demonstrated in the growth media of arsenic hyperaccumulator Pteris vittata L. All arsenite (AsIII) at 0.1 mM in the media was oxidized after 48 h incubation. Oxidation was largely inhibited by antibiotics, indicating that bacteria played a dominant role. To identify AsIII oxidizing bacteria, degenerate primers were used to amplify 500 bp of the AsIII oxidase gene aioA (aroA) using DNA extracted from the media. One aioA (aroA)-like sequence (MG-1, tentatively identified as Acinetobacter sp.) was amplified, exhibiting 82% and 91% identity in terms of gene and deduced protein sequence to those from Acinetobacter sp. 33. In addition, four bacterial strains with different arsenic tolerance were isolated and identified as Comamonas sp.C-1, Flavobacterium sp. C-2, Staphylococcus sp. C-3, and Pseudomonas sp. C-4 using carbon utilization, fatty acid profiles, and/or sequencing 16s rRNA gene. These isolates exhibited dual capacity for both AsV reduction and AsIII oxidation under ambient conditions. Arsenic-resistant bacteria with strong AsIII oxidizing ability may have potential to improve bioremediation of AsIII-contaminated water using P. vittata and/or other biochemical strategies. [ABSTRACT FROM AUTHOR]

Direct application of benzyl alcohols (or their magnesium salts) as electrophiles in various reactions with Grignard reagents has been developed via transition metal-catalyzed sp3 C-O bond activation. Ni complex was found to be an efficient catalyst for the first direct cross coupling of benzyl alcohols with aryl/alkyl Grignard reagents, while Fe, Co, or Ni catalysts could promote the unprecedented conversion of benzyl alcohols to benzyl Grignard reagents in the presence of nhexylMgCl. These methods offer straightforward pathways to transform benzyl alcohols into a variety of functionalities. [ABSTRACT FROM AUTHOR]

Glyconanomaterials have shown high potential in applications including bioanalysis and nanomedicine. Here, a quantitative analytical technique, based on isothermal titration calorimetry, was developed to characterize the interactions between glyconanoparticles and lectins. By titrating lectins into the glyconanoparticte solution, the apparent dissociation constant, thermodynamic parameters, and the number of binding sites were derived simultaneously. For the glyconanoparticles-lectin binding pairs investigated, a 3-S order of magnitude affinity enhancement over the free tigand-lectin interactions was observed which can be attributed to the multivalent ligand presentation on the nanoparticles. The impact of ligand density was also studied, and results showed that the affinity increased with the number of glycans on the nanopartide. [ABSTRACT FROM AUTHOR]

We report a new type of microarray, based on glyconanoparticles (GNPs), to study glycan—lectin interactions. GNPs, synthesized by conjugating carbohydrate ligands on silica nanoparticles, were printed on a photoactive surface followed by covalent immobilization by light activation. The GNP microarrays could be probed by lectins labeled with fluorescein as well as fluorescein-doped silica nanoparticles (FSNPs). Results showed that FSNP as the label enhanced the signals for the higher affinity ligands than the lower ones. [ABSTRACT FROM AUTHOR]

{[Cu6(pybz)8(OH)2]·I5-·I7-}n (1), obtained hydrothermally by using iodine molecules as a versatile precursor template, consists of a cationic framework with two types of zigzag channels, which segregate I5- and I7- anions. The framework exhibits the first observed bipillared-bilayer structure featuring both interdigitation and interpenetration. 1 displays high framework stability in both acidic (HCl) and alkaline (NaOH) solutions. 1 slowly releases iodine in dry methanol to give [Cu6(pybz)8(OH)2](I-)2·3.5CH3OH (1') and partially recovers iodine from cyclohexane to form [Cu6(pybz)8(OH)2](I-)2·xI2 (1"). Differences of up to 100 times in electrical conductivity and of 4 times in nonlinear optical activity (NLO) have been measured between 1 and 1'. This compound is one of few displaying multifunctionality, electrical conductivity, NLO, and crystal-crystal stability upon release and recovery of iodine. It is also unique in the iodine release from polyiodide anions in a metal-organic framework. [ABSTRACT FROM AUTHOR]

One of the factors hindering the development of technologies that rely on the use of proton-conducting polyelectrolyte membranes is the lack of control over the membrane morphology on the nanoscale. Of particular importance is the rearrangement and clustering of acidic groups, which may seriously degrade the electrical properties. Although electron microscopy is capable of imaging the morphology of the clusters, images of unmodified membranes with sufficient quality to discriminate between different proposed cluster morphology models have not been presented. Here we show the first determination of the cluster size distribution in a model polymer electrolyte membrane from electron micrographs of individual acidic clusters. Imaging of the sulfur-rich clusters by dark-field microscopy was facilitated by the spontaneous formation of thin, cluster-containing layers on the top and bottom surfaces of free-standing films with a thickness of ∼35 nm. [ABSTRACT FROM AUTHOR]

Arsenate (AsV) and arsenite (AsIII) are two dominant arsenic species in the environment. While arsenate uptake is via phosphate transporter in plants, including arsenic hyperaccumulator Pteris vittata, AsIII uptake mechanisms by P. vittata are unclear. In this study, we investigated AsIII uptake by P. vittata involving root radial transport from external medium to cortical cells and xylem loading. In the root symplastic solution, AsIII was the predominant species (90-94%) and its concentrations were 1.6-21 times those in the medium. AsIII influx into root symplast followed Michaelis-Menten kinetics with Km of 77.7 μM at external AsIII concentrations of 2.6-650 μM. In the presence of metabolic inhibitor 2,4-dinitrophenol (DNP), arsenic concentrations in the root symplast were reduced to the levels lower than in the medium, indicating that a transporter-mediated active process was mainly responsible for AsIII influx into P. vittata roots. Unlike radial transport, AsIII loading into xylem involved both high- and low-affinity systems with Km of 8.8 μM and 70.4 μM, respectively. As indicated by the effect of 2,4-DNP, passive diffusion became more important in arsenic loading into xylem at higher external AsIII. The unique AsIII uptake system in P. vittata makes it a valuable model to understand the mechanisms of arsenic hyperaccumulation in the plant kingdom. [ABSTRACT FROM AUTHOR]

Taking the synthesis of Sb2Se3nanostructures as an example, a novel gas-induced-reduction method to obtain chalcogenide nanostructures was developed, using antimony ethylene glycolate and selenium oxide as the raw materials and hydrazine as a gas reductant. In the heating process, hydrazine volatilizes and dissolves into a colloidal reaction system, the pressure for the system is flexible, and the chemical reaction/nucleation rate can be modulated. A mass of uniform one-dimensional Sb2Se3nanostructures, featuring different aspect ratios, were synthesized at 180–280 °C. The synergistic effects of process parameters including temperature, precursor concentration, and heating mode on the morphology and growth behavior of the products were investigated. The products could be transformed from nanowires to nanobelts by adjusting the precursor concentration and heating mode. The formation and growth mechanisms of the products were studied in detail. The electrical conductivity of an individual Sb2Se3nanowire increased gradually from 10–2to 102S·m–1as temperature increased from room temperature to 285 °C, exhibiting intrinsic semiconductor behavior. [ABSTRACT FROM AUTHOR]

Doping effects on the structural and electronic properties of ladderanes and ladder polysilanes have been studied using density functional theory. Two types of doping: substitution with isoelectronic atoms or heteroatoms (or radicals), have been used to design low band gap ladderanes. It is found that the B-doped [n]-ladderanes and 1,2 P-doped [n]-silaladderanes exhibit a very noticeable bent conformation, whereas the 1,2 and 1,3 N-doped ladderanes, P-doped ladderanes, and silaladderanes keep the relatively straight ladder shapes. The isoelectronic atom doping reduces the HOMO--LUMO (H-L) gaps of [n]-ladderanes but increases those of [n]-silaladderanes with n > 5. The present results show that isoelectronic atom doping is not an effective way to decrease the H-L gaps of ladderanes and silaladderanes. Heteroatom doping has a more pronounced effect than the isoelectronic atom doping. The HOMOs of heteroatom-doped ladderanes and silaladderanes are destabilized and LUMOs are stabilized, leading to significant reduction of H-L gaps. Most of the B-, N-, and P-doped [n]-silaladderanes we designed have H-L gaps below 1.5 eV. Therefore, it is expected that these silaladderanes are promising candidates of conductive or semiconductive materials. The heteroatom doping is a viable approach to reduce H-L gaps for the silaladderanes. In addition, it is found that nine different density functionals, including B3LYP, SVWN LDA, four pure GGAs, and three hybrid GGAs, as well as the time-dependent B3LYP method, all lead to the same predictions on the H-L gaps of ladderanes, silaladderanes, as well as their doped derivatives. [ABSTRACT FROM AUTHOR]

A magnetically separable ZnFe2O4–graphene nanocomposite photocatalyst with different graphene content was prepared by a facile one-step hydrothermal method. The graphene sheets in this nanocomposite photocatalyst are exfoliated and decorated with ZnFe2O4nanocrystals. It was found that in the presence of H2O2, the photodegradation rate of methylene blue (MB) was 88% after visible light irradiation for only 5 min and reached up to 99% after irradiation for 90 min. In comparison with pure ZnFe2O4catalyst, ZnFe2O4–graphene serves a dual function as the catalyst for photoelectrochemical degradation of MB and the generator of a strong oxidant hydroxyl radical (·OH) via photoelectrochemical decomposition of H2O2under visible light irradiation. ZnFe2O4nanoparticles themselves have a magnetic property, which makes the ZnFe2O4–graphene composite magnetically separable in a suspension system, and therefore it does not require additional magnetic components as is the usual case. [ABSTRACT FROM AUTHOR]

Using ionic liquids for CO2capture is of great interest due to their unique characteristics. However, low gas–liquid mass transfer rates in conventional gas–liquid contactors due to the high viscosities of ionic liquids lead to the significant limitation for large-scale application of CO2capture using ionic liquids. Therefore, there is an urgent demand to develop a novel gas–liquid contactor for the intensification of the mass transfer efficiency in such a system. In this article, CO2absorption with an ionic liquid in a rotating packed bed (RPB) gas–liquid contactor is first reported. It was found that the RPB markedly enhanced the physical absorption of CO2in the ionic liquid in a very short contact time, within seconds. Only one cycle gas–liquid contact in the RPB could make the saturation ratio of CO2in the ionic liquid reach 60%. The effects of various operation conditions on the liquid side volumetric mass transfer coefficient (kLα) were elucidated. Increasing the rotating speed from 1100 to 3100 rpm doubled the kLα. The increase of the liquid flow rate also benefited the enhancement of the kLα. The experimentally measured kLα in the RPB is at least 1 order of magnitude higher than that in a conventional packed tower. A model based on penetration theory was proposed to describe the mechanism of gas–liquid mass transfer in the RPB. The predicted kLα was in good agreement with the experimental data with a deviation of less than 15%. The RPB shows great potential for the industrial application of CO2capture using ionic liquids. [ABSTRACT FROM AUTHOR]

We report a novel core-shell-structured ternary nanocube of MnZn ferrite synthesized by controlling the reaction temperature and composition in the absence of conventionally used reducing agents. The highly monodispersed core-shell structure consists of an Fe3O4 core and an MnZn Ferrite shell. The observation of a Moiré pattern indicates that the core and the shell are two highly crystalline materials with slightly different lattice constants that are rotated relative to each other by a small angle. The ternary core-shell nanocubes display magnetic properties regulated by a combination of the core-shell composition and exhibit an increased coercivity and field-cooled/zero-field-cooled characteristics drastically different from those of regular MnZn ferrite nanoparticles. The ability to engineer the spatial nanostructures of ternary magnetic nanoparticles in terms of shape and composition offers atomic-level versatility in fine-tuning the nanoscale magnetic properties. [ABSTRACT FROM AUTHOR]

The silica/polymer hybrid hollow nanoparticles with channels and gatekeepers were successfully fabricated with a facile strategy by using thermoresponsive complex micelles of poly(ethylene glycol)-b-poly(N-isopropylacrylamide) (PEG-b-PNIPAM) and poly(N-isopropylacrylamide)-b-poly(4-vinylpyridine) (PNIPAM-b-P4VP) as the template. In aqueous solution, the complex micelles (PEG-b-PNIPAM/PNIPAM-b-P4VP) formed with the PNIPAM block as the core and the PEG/P4VP blocks as the mixed shell at 45 °C and pH 4.0. After shell cross-linking by 1,2-bis(2-iodoethoxyl)ethane (BIEE), tetraethylorthosilicate (TEOS) selectively well-deposited on the P4VP block and processed the sol−gel reaction. When the temperature was decreased to 4 °C, the PNIPAM block became swollen and further soluble, and the PEG-b-PNIPAM block copolymer escaped from the hybrid nanoparticles as a result of swelled PNIPAM and weak interaction between PEG and silica at pH 4.0. Therefore, the hybrid hollow silica nanoparticles with inner thermoresponsive PNIPAM as gatekeepers and channels in the silica shell were successfully obtained, which could be used for switchable controlled drug release. In the system, the complex micelles, as a template, could avoid the formation of larger aggregates during the preparation of the hybrid hollow silica nanoparticles. The thermoresponsive core (PNIPAM) could conveniently control the hollow space through the stimuli-responsive phase transition instead of calcination or chemical etching. In the meantime, the channel in the hybrid silica shell could be achieved because of the escape of PEG chains from the hybrid nanoparticles. [ABSTRACT FROM AUTHOR]

Glyconanomaterials, nanomaterials canying multiple carbohydrate ligands, provide an excellent platform for sensitive protein recognition. Using nanomaterials as the scaffold, multivalent interactions between glycan ligands and pmteins have been demonstrated. However, the quantitative analysis of the binding affinity of these glyconanomaterials has been lacking. In this Article, we report a new method to measure the binding affinity of glyconanoparticle (GNP)-protein interactions based on a fluorescent competition binding assay, which yielded the apparent dissociation constant (Kd) of GNPs with the interacting protein. Au nanoparticles conjugated with underivatized mono-, oligo-, and polysaccharides were synthesized using our recently developed photo coupling chemistry. The affinities of these GNPs with lectins were measured and were several orders of magnitude higher than the corresponding free ligands with lectins. The effect of ligand display on the binding affinity of GNPs was, furthermore, studied where GNPs of varying linker type, spacer length, ligand density, and nanoparticle size were prepared and Kd values determined. The long spacer linker containing hydrocathon and ethylene oxide units gave the highest binding affinity as well as assay sensitivity. The binding affinity increased with ligand density in general, showing a drastic increase in affinity at low ligand density. In addition, the affinity enhancement was more pronounced on smaller NPs than the larger ones. These results not only demonstrate that the binding affinity of GNPs is highly influenced by how the ligands are presented on the nanoparticles but also pave the way for tailor-made glyconanomaterials with tunable affinity by way of ligand display. [ABSTRACT FROM AUTHOR]

A microporous tube-in-tube microchannel reactor (MTMCR) was successfully adopted to prepare hydroxyapatite (HAP) nanoparticles. The rodlike HAP nanoparticles with a mean size of 58 nm, a specific surface area of 49.32 m2/g, and a narrow size distribution were obtained in an MTMCR under a high throughput of 3 L/min. The mean particle size sharply decreased with increasing the continuous phase flow rate, while first decreased and subsequently increased with increasing the dispersed phase flow rate and the reactant concentration. The extension of the mixing distance led to the initial rapid and following slight decrease of the mean particle size. The size of HAP nanoparticles was also strongly dependent on the micropore size on the surface of inner tube. Small micropore size was beneficial for producing small particles. For comparison, HAP nanoparticles were also prepared in a stirred tank reactor (STR) and a T-junction microchannel reactor (TMCR), clearly exhibiting the advantages of the MTMCR over the STR and TMCR due to the achievement of uniformly smaller HAP nanoparticles and a high throughput for industrial production. [ABSTRACT FROM AUTHOR]

Imidazo[1,5-a]pyrazines 1undergo regioselective C3-metalation and C5/C3-dimetalation to afford a range of functionalized derivatives 2a−2g(Table 1), and 4a−4d(Table 2). Under similar conditions, the C3-methyl derivatives 2aand 5undergo surprising regioselective C5-deprotonation to afford, after electrophile quench, products 4b and 6a−6p(Table 3), results that are rationalized by quantum mechanical calculations. Benzamide 7b, obtained from such metalation chemistry followed by Suzuki cross coupling, undergoes directed remote metalation-cyclization to afford 8, representing the hitherto unknown triazadibenzo[cd,f]azulen-7(6H)-one tricyclic ring system. [ABSTRACT FROM AUTHOR]

High-density aligned n-type silicon nanowire (SiNW) arrays decorated with discrete 5−10 nm platinum nanoparticles (PtNPs) have been fabricated by aqueous electroless Si etching followed by an electroless platinum deposition process. Coating of PtNPs on SiNW sidewalls yielded a substantial enhancement in photoconversion efficiency and an apparent energy conversion efficiency of up to 8.14% for the PtNP-decorated SiNW-based photoelectrochemical solar cell using a liquid electrolyte containing Br−/Br2redox couple. The results demonstrate PtNP-decorated SiNWs to be a promising hybrid system for solar energy conversion. [ABSTRACT FROM AUTHOR]

Flat electrodes are useful in microbial fuel cells (MFCs) as close electrode spacing improves power generation. Carbon cloth and carbon paper materials typically used in hydrogen fuel cells, however, are prohibitively expensive for use in MFCs. An inexpensive carbon mesh materiel was examined here as a substantially less expensive alternative to these materials for the anode in an MFC. Pretreatment of the carbon mesh was needed to ensure adequate MFC performance. Heating the carbon mesh in a muffle furnace (450 °C for 30 min) resulted in a maximum power density of 922 mW/m2 (46 W/m3) with this heat-treated anode, which was 3% more power than that produced using a mesh anode cleaned with acetone (893 mW/m2 45 W/m3). This power density with heating was only 7% less than that achieved with carbon cloth treated by a high temperature ammonia gas process (988 mW/m2 49 W/m3). When the carbon mesh was treated by the ammonia gas process. power increased to 1015 mW/m2 (51 W/m3). Analysis of the cleaned or heated surfaces showed these processes decreased atomic O/C ratio, indicating removal of contaminants that interfered with charge transfer. Ammonia gas treatment also increased the atomic N/C ratio, suggesting that this process produced nitrogen related functional groups that facilitated electron transfer. These results show that low cost heat-treated carbon mesh materials can be used as the anode in an MFC, providing good performance and even exceeding performance of carbon cloth anodes. [ABSTRACT FROM AUTHOR]

Chiral complex micelles prepared by 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) and the poly(ethylene glycol)-block-poly(4-vinylpyridine) (PEG114-b-P4VP61) in the presence of aspartic acid (Asp), tryptophan (Trp), and lysine (Lys) were investigated in aqueous solutions at pH 2.0. TPPS formed J-aggregates in the micellar core. The morphology and optical properties of the complex micelles depended on the properties of amino acids and the preservation time for the mixed solutions of TPPS and amino acids before adding the copolymer. Prolonging the preservation time, the spherical morphology of the complex micelles remained unchanged in the presence of the Asp. On the contrary, a morphology evolution from sphere to rod took place for Trp and Lys. The intensity of the circular dichroism (CD) signals of the complex micelles increase with the preservation time, and the chirality sign was determined by amino acids. l-Trp and l-Lys led to a negative chirality sign and l-Asp a positive one while the corresponding enantiomers contributed to the opposite sign. Lower concentration of amino acids could not transfer their chirality to the aggregates of TPPS, and at higher concentrations of TPPS, it took more time for the aggregates to express the chiral information on amino acids. [ABSTRACT FROM AUTHOR]

Corn stover is usually treated by an energy-intensive or expensive process to extract sugars for bioenergy production. However, it is possible to directly generate electricity from corn stover in microbial fuel cells (MFCs) through the addition of microbial consortia specifically acclimated for biomass breakdown. A mixed culture that was developed to have a high saccharification rate with corn stover was added to single-chamber, air-cathode MFCs acclimated for power production using glucose. The MFC produced a maximum power of 331 mW/m² with the bioaugmented mixed culture and corn stover, compared to 510 mW/m² using glucose. Denaturing gradient gel electrophoresis (DGGE) showed the communities continued to evolve on both the anode and corn stover biomass over 60 days, with several bacteria identified including Rhodopseudomonas palustris. The use of residual solids from the steam exploded corn stover produced 8% more power (406 mW/m²) than the raw corn stover. These results show that it is possible to directly generate electricity from waste corn stover in MFCs through bioaugmentation using naturally occurring bacteria. [ABSTRACT FROM AUTHOR]

A series of spacer-free ionic azobenzene-containing stoichiometric complexes was prepared from monosulfonated azo dyes and cationic polyelectrolytes [methylated poly(4-vinylpyridine) (PVP) and poly(dimethylaminoethyl methacrylate) (PDM)]. Their thermal and structural characteristics and optical responses, particularly photoinduced birefringence (PIB) and surface relief grating (SRG) inscription, were investigated as a function of selected molecular parameters. All of the complexes have high apparent Tgvalues, 180−210 °C, and show liquid crystal (LC) order of the single-layer SmA type from ambient to very high temperature, usually to degradation. The range of LC order is greater in the complexes of chromophores with longer alkyl tails and shorter in the complex of the chromophore with an OH end group and the complex of methyl orange (MO) with PDM. PIB, SRG quality, and diffraction efficiency were all shown to depend in a similar way on molecular structural features: the more rigid the molecular structure, the higher the PIB, the better its thermal and temporal stability, and the greater the SRG amplitude. Thus, a flexible alkyl unit in the polyelectrolyte component or in the chromophore tail or spacer reduces the optical performance, with a clear dependence on alkoxy tail length (e.g., no SRG formation was observed for the complex with a hexoxy tail), whereas the most rigid complex, MO/PVP, provides the best performance, contrasting with many previous literature reports that suggest a beneficial role for flexible spacers. The present paper shows that flexible moieties increase relaxation of photoinduced orientation. The hydroxyl end group also provides much improved PIB and SRG performance, attributed to its rigid structure along with a (temperature-dependent) physical cross-linking effect of H-bonding interactions. [ABSTRACT FROM AUTHOR]

Cationic polymers have been studied as promising nonviral gene delivery vectors. In contrast to the conventional polycations with long sequences of covalently bonded repeating units, we have developed a series of novel cationic polyrotaxanes consisting of multiple oligoethyleneimine-grafted β-cyclodextrin rings threaded on a poly(ethylene glycol)−poly(propylene glycol)−poly(ethylene glycol) triblock copolymer chain. In this study, these cationic polyrotaxanes with different oligoethyleneimine chain lengths were investigated for DNA binding ability, cytotoxicity, and gene transfection efficiency in cancer cells. Fluorescent titration assay results indicated that all the polyrotaxanes could completely condense plasmid DNA and form stable complexes at N/P ratio of 2, where the N/P ratio is the molar ration of amine groups in the cationic molecule to phosphate groups in the DNA. Particularly, tapping mode AFM imaging in aqueous environment was conducted to observe the morphology of the polyrotaxane/DNA complexes and their formation processes in real time. In both SK-OV-3 and PC3 cancer cells, these polyrotaxanes showed low cytotoxicity and high transfection efficiency which is comparable to or significantly higher than that of high molecular weight branched polyethylenimine (25 kDa), one of the most effective gene-delivery polymers studied to date. In addition, the synthesized polyrotaxanes displayed sustained gene delivery capability in PC3 cells in the presence or absence of serum. Therefore, these cationic polyrotaxanes with strong DNA binding ability, low cytotoxicity, and high and sustained gene delivery capability have a high potential as novel nonviral gene carriers in clinical cancer gene therapy. [ABSTRACT FROM AUTHOR]

An investigation has been undertaken to study the large closed ladderanes C24H24and their analogs. Thirteen isoelectronic species have been identified as local minima on the MP2(FU)/6-31G(d) potential energy surface, including three C24H24, four Si24H24, two N24,and four C24−xH24−xNx(x= 6, 8, 12) isomers. Of these 13 species, 11 are reported for the first time. Their structures, stabilities, HOMO−LUMO gaps, and G3(MP2) heats of formations are computationally obtained and discussed. These results are also compared with those of the related species already available in the literature. Our results show that molecules with 12-membered rings are highly energetic and much less stable than their corresponding isomers that do not have such rings. Isomer IIof Si24H24with anticonformations has a very small HOMO−LUMO gap of 2.56 eV, approaching the semiconductor range. Therefore, it is a candidate of potential semiconductor materials. Meanwhile, the N24and other nitrogen-containing species are candidates for high-energy density materials. Our results also indicate that C18H18N6and C16H16N8may be good hexa- and octadentate ligands for metal cations. [ABSTRACT FROM AUTHOR]

A new synthesis method for the preparation of high-performance PtRu electrocatalysts on multiwalled carbon nanotubes (MWCNTs) is reported. In this method, bimetallic PtRu electrocatalysts are deposited onto 1-aminopyrene (1-AP)-functionalized MWCNTs by a microwave-assisted polyol process. The noncovalent functionalization of MWCNTs by 1-AP is simple and can be carried out at room temperature without the use of expensive chemicals or corrosive acids, thus preserving the integrity and the electronic structure of MWCNTs. PtRu electrocatalysts on 1-AP-functionalized MWCNTs show much better distribution with no formation of aggregates, higher electrochemically active surface area, and higher electrocatalytic activity for the electrooxidation of methanol in direct methanol fuel cells as compared to that on conventional acid-treated MWCNTs and carbon black supported PtRu electrocatalysts. PtRu electrocatalysts on 1-AP-functionalized MWCNTs also show significantly enhanced stability. [ABSTRACT FROM AUTHOR]

A general and efficient synthesis of 5-aryl imidazo[1,5- a]pyrazines by palladium-catalyzed coupling of the corresponding 8-substituted derivatives with aryl halides is described. The scope of this new reaction for the imidazo[1,5- a]pyrazine ring system was explored using three readily available 8-substituted precursors, X = NH 2, NMe 2, and OMe, as well as 8-aryl derivatives, X = Ar′. On the basis of these results as well as studies using a deuterated derivative, a Heck-like mechanism is proposed for this transformation. [ABSTRACT FROM AUTHOR]

Olivary Sb 2S 3microcrystallines have been first synthesized via a hydrothermal process at 180 °C for 24 h using hydrochloric acid, SbCl 3, and Na 2S as starting materials. The powder X-ray diffraction (XRD) pattern shows the product corresponds to the pure orthorhombic phase of Sb 2S 3, the phase purity of which is further confirmed by energy dispersive X-ray (EDX). Transmission electron microscopic (TEM) and scanning electron microscopy (SEM) studies reveal that the irregular shaped nanobricks self-assemble into hollow olivary Sb 2S 3microstructures. The possible mechanistic pathways in the formation of the structures are discussed. [ABSTRACT FROM AUTHOR]

Microchannel reactors are a rapidly emerging and promising technology field for their enhanced mass transfer and excellent heat exchange induced by dimensional effects. A method, the liquid antisolvent precipitation (LASP) process in a microchannel reactor (MCR), is proposed here to directly synthesize danazol nanoparticles without additives. The mean particle size decreased from 55 m to 364 nm, and the specific surface area increased from 0.66 to 14.37 m2/g after the LASP process in MCR. The mean particle size can be facilely controlled by regulating the parameter of the MCR setup. The chemical composition and physical characteristics of the as-prepared danazol nanoparticles were demonstrated to be unchanged after processing according to FT-IR and XRD analyses. Correspondingly, the dissolution rate of the nanoparticles within 5 min was enhanced from 35% to 100% compared to the raw danazol particles. Combined with the controlled LASP method, MCR exhibits great potential for preparation of hydrophobic drugs with uniform particle size distribution in the nanometer range. [ABSTRACT FROM AUTHOR]