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A facile top-down approach to fabricate uniform single-crystal [alpha]-[Fe.sub.2][O.sub.3] nanodiscs via selective oxalic acid etching is reported. The approach could also be applied to generate [alpha]-[Fe.sub.2][O.sub.3], melon-like microparticles with contrasting textural properties.

Anatase Ti[O.sub.2] is used for showing a facile approach for creating high-surface-area stable nanosheets comprising nearly 100% exposed (001) facets. The high surface density of exposed Ti[O.sub.2] (001) facets has led to fast lithium insertion/deinsertion processes in batteries that mimic features seen in high-power electrochemical capacitors.

The first highly enantioselective Friedel-Crafts reaction of indoles with imines with a chiral organic catalyst is reported. This reaction provides a direct and broadly useful catalytic enantioselective approach toward 3-indolyl methanamines, which should facilitate the asymmetric synthesis of biologically interesting indole compounds.

The first highly enantioselective catalytic conjugate addition to vinyl sulfones are developed. The synthetic utility of the optically active chiral sulfones is demonstrated in the development of a versatile catalytic enantioselective approach toward alpha, alpha-disubstituted amino acids.

Luminescent solar concentrators (LSCs) can serve as large-area sunlight collectors for photovoltaic devices. An important LSC characteristic is a concentration factor (C), which is defined as the ratio of the output and the input photon flux densities. This parameter can be also thought of as an effective enlargement factor of a solar cell active area. On the basis of thermodynamic considerations, the C-factor can reach extremely high values that exceed those accessible with traditional concentrating optics. In reality, however, the best reported values of C are around 30. Here we demonstrate that using a new type of high-emissivity quantum dots (QDs) incorporated into a specially designed cavity, we are able to achieve the C of ~62 for spectrally integrated emission and ~120 for the red portion of the photoluminescence spectrum. The key feature of these QDs is a seed/quantum-well/thick-shell design, which allows for obtaining a high emission quantum yield (>95%) simultaneously with a large LSC quality factor (QLSC of ~100) defined as the ratio of absorption coefficients at the wavelengths of incident and reemitted light. By incorporating the QDs into a specially designed cavity equipped with a top selective reflector (a Bragg mirror or a thin silver film), we are able to effectively recycle reemitted light achieving light trapping coefficients of ~85%. The observed performance of these devices is in remarkable agreement with analytical modeling, which allows us to project that the applied approach should allow one to boost the spectrally integrated concentration factors to more than 100 by further improving light trapping and/or increasing QLSC. [ABSTRACT FROM AUTHOR]

The density, viscosity, and heat capacity of aqueous potassium serinate solutions were measured over the temperature range from (298.15 to 353.15) K in the mass fraction range of (7.2 to 57.3) %. Each physical property was correlated with temperature and mass fraction, by regression analysis, and the corresponding coefficients for each property are presented here. The surface tension of the aqueous potassium serinate solution was also measured over the mass fraction range of (7.2 to 57.3) % at 298.15 K. In addition, the solubility of carbon dioxide in a 14.3 mass % aqueous potassium serinate solution was measured at (313.15, 343.15, and 373.15) K over partial pressures of CO2ranging from (0.1 to 400) kPa. It was shown that the aqueous potassium serinate solution could be a good CO2absorbent because of its high cyclic CO2absorption capacity. Furthermore, it might be suitable for membrane gas absorption due to its higher surface tension. [ABSTRACT FROM AUTHOR]

Synthesis of nanocrystals with exposed high-energy facets is a well-known challenge in many fields of science and technology. The higher reactivity of these facets simultaneously makes them desirable catalysts for sluggish chemical reactions and leads to their small populations in an equilibrated crystal. Using anatase TiO2 as an example, we demonstrate a facile approach for creating high-surface-area stable nanosheets comprising nearly 100% exposed (001) facets, Our approach relies on spontaneous assembly of the nanosheets into three-dimensional hierarchical spheres, which stabilizes them from collapse. We show that the high surface density of exposed TiO2 (001) facets leads to fast lithium insertion/deinsertion processes in batteries that mimic features seen in high-power electrochemical capacitors. [ABSTRACT FROM AUTHOR]

One-dimensional (1D) AMoO4·nH2O (A = Ni, Co) nanorods have been synthesized by a facile hydrothermal method. The effect of different synthetic conditions on the morphologies of the final products was systematically investigated. The size of the nanorods can be easily controlled by adding ethanol in the synthetic solution. For the first time, the self-assembled growth of oriented NiMoO4·nH2O nanorod arrays on Ti-foil substrates was achieved. The thermal dehydration and phase transformation processes of AMoO4·nH2O nanorods were thoroughly investigated by TG-DTA and time-resolved synchrotron XRD. As-prepared hydrate nanorods can be further converted to corresponding AMoO4nanorods by annealing at 300−600 °C for 1 h without significant alteration of 1D morphology. Electrochemical lithium storage capabilities of dehydrated AMoO4nanorods have been investigated. The results suggest their potential use as cathode materials for lithium ion batteries. [ABSTRACT FROM AUTHOR]

We report a simple glucose-mediated hydrothermal method for gram-scale synthesis of nearly monodisperse hybrid SnO2nanoparticles. Glucose is found to play the dual role of facilitating rapid precipitation of polycrystalline SnO2nanocolloids and in creating a uniform, glucose-derived, carbon-rich polysaccharide (GCP) coating on the SnO2nanocores. The thickness of the GCP coating can be facilely manipulated by varying glucose concentration in the synthesis medium. Carbon-coated SnO2nanocolloids obtained after carbonization of the GCP coating exhibit significantly enhanced cycling performance for lithium storage. Specifically, we find that a capacity of ca. 440 mA h/g can be obtained after more than 100 charge/discharge cycles at a current density of 300 mA/g in hybrid SnO2-carbon electrodes containing as much as 1/3 of their mass in the low-activity carbon shell. By reducing the SnO2-carbon particles with H2, we demonstrate a simple route to carbon-coated Sn nanospheres. Lithium storage properties of the latter materials are also reported. Our results suggest that large initial irreversible losses in these materials are caused not only by the initial, presumably irreversible, reduction of SnO2as generally perceived in the field, but also by the formation of the solid electrolyte interface (SEI). [ABSTRACT FROM AUTHOR]

Three new 16-norphragmalin limonoids, chukvelutins A−C (1−3), were isolated from the stem bark of Chukrasia tabularisvar. velutina, which possess unprecedented skeletons, featured with a characteristic ketal moiety between the phragmalin skeleton and a biosynthetically extended isobutyryl group at C-15. Their structures were elucidated by extensive spectroscopic technologies. [ABSTRACT FROM AUTHOR]

The physical solubility and diffusivity of N2O and CO2in aqueous sodium glycinate (SG) solutions of various concentrations (1.0−3.5 kmol/m3) and temperatures (303.15−323.15 K) were reported. The kinetics of the reaction between CO2and SG has been studied using absorption data measured by a wetted-wall column apparatus at various temperatures and concentrations. The second-order rate constant of CO2with SG was determined to be k2(m3kmol-1s-1) 1.95 × 1013exp(−7670/T), where Tis the absolute temperature (given in Kelvin). The activation energy for the reaction of CO2with SG was calculated to be 63.8 kJ/mol. [ABSTRACT FROM AUTHOR]

The instability of carbamate-protected alkyl imines has greatly hampered the development of catalytic asymmetric Mannich reactions suitable for the synthesis of optically active carbamate-protected chiral alkyl amines. A highly enantioselective Mannich reaction with in situ generation of carbamate-protected imines from stable -amido sulfones catalyzed by an organic catalyst was developed. This reaction provides a concise and highly enantioselective route converting aromatic and aliphatic aldehydes into optically active aryl and alkyl -amino acids. [ABSTRACT FROM AUTHOR]

α-Fe2O3 hollow spheres with sheet-like subunits are synthesized by a facile quasiemulsion-templated method. Glycerol is dispersed in water to form oil-in-water quasiemulsion microdroplets, which serve as soft templates for the deposition of the α-Fe2O3 shell. When tested as anode materials for lithium-ion batteries, these α-Fe2O3 hollow spheres manifest greatly enhanced Li storage properties. [ABSTRACT FROM AUTHOR]

We report an interesting approach for efficient synthesis of SnO2 hollow spheres inside mesoporous silica "nanoreactors". The as-prepared products are shown to have a uniform size distribution and good structural stability. When evaluated for their lithium storage properties, these SnO2 hollow spheres manifest improved capacity retention. [ABSTRACT FROM AUTHOR]

In this work, we report a facile top-down approach to fabricate uniform single-crystal α-Fe2O3 nanodiscs via selective oxalic acid etching. Phosphate ions are employed as a capping agent to control the etching to along the [001] direction. We also show that α-Fe2O3 melon-like microparticles with contrasting textural properties can be generated using the same approach. The etched particles exhibit a much larger total pore volume and average pore size compared to the pristine ones, thus serving as the possible origin for their greatly enhanced capacity retention when tested as potential anode materials for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

The article describes the application of cooperative hydrogen-bonding catalysis to develop a cinchona alkaloid-catalyzed, highly enantioselective Mannich reaction with malonates and N-Boc imines. Chiral hydrogen-bond donors were shown as effective catalysts for the activation of simple imines toward various enantioselective nucleophilic additions including Mannich reactions with enolsilane and 1,3-diketones. Also, chiral hydrogen-bond acceptors have been identified for the activation of malonates for enantioselective conjugate additions. The results suggest that cinchona alkaloid derivatives bearing a thiourea functionality might act as efficient bifunctional catalysts for a Mannich reaction of malonates with simple imines.

Electrocarboxylation of organic halides is one of the most investigated electrochemical approaches for converting thermodynamically inert carbon dioxide (CO 2 ) into value-added carboxylic acids. By converting organic halides into their sulfone derivatives, we have developed a highly efficient electrochemical desulfonylative carboxylation protocol. Such a strategy takes advantage of CO 2 as the abundant C1 building block for the facile preparation of multifunctionalized carboxylic acids, including the nonsteroidal anti-inflammatory drug ibuprofen, under mild reaction conditions.

Metal selenides are considered as a group of promising candidates as the anode material for sodium-ion batteries due to their high theoretical capacity. However, the intrinsically low electrical and ionic conductivities as well as huge volume change during the charge-discharge process give rise to an inferior sodium storage capability, which severely hinders their practical application. Herein, we fabricated In 2 Se 3 /CoSe 2 hollow nanorods composed of In 2 Se 3 /CoIn 2 /CoSe 2 by growing cobalt-based zeolitic imidazolate framework ZIF-67 on the surface of indium-based metal-organic framework MIL-68, followed by in situ gaseous selenization. Because of the CoIn 2 alloy phase in between In 2 Se 3 and CoSe 2 , a heterostructure consisting of two alloy/selenide interfaces has been successfully constructed, offering synergistically enhanced electrical conductivity, Na diffusion process, and structural stability, in comparison to the single CoIn 2 -free interface with only two metal selenides. As expected, this nanoconstruction delivers a high reversible capacity of 297.5 and 205.5 mAh g -1 at 5 and 10 A g -1 after 2000 cycles, respectively, and a superior rate performance of 371.6 mAh g -1 at even 20 A g -1 .

Serratia marcescens NJ01 is a pathogenic bacterium isolated from diseased tomato leaves. Here, we report on the development of a tomato- S. marcescens host-pathogen system as a model to evaluate the effects of hordenine on quorum sensing (QS)-mediated pathogenicity under native conditions. Exposure to hordenine at 25, 50, and 100 μg/mL significantly inhibited the production of acyl-homoserine lactones and the formation of biofilms. Hordenine treatment notably enhanced the susceptibility of the preformed biofilms to ciprofloxacin by reducing the production of extracellular polysaccharides, destroying the architecture of biofilms, and changing the permeability of membranes, as evidenced by the scattered appearance and dominant red fluorescence in the combination-treated biofilms. Furthermore, the addition of hordenine affected the production of virulence factors, influenced the intracellular metabolites, and downregulated the expressions of QS- and biofilm-related genes. The plant infection model indicated that hordenine could significantly attenuate the pathogenicity of S. marcescens NJ01 in tomato plants. Thus, hordenine could act as a potential pesticide or pesticide accelerant in treating crop infections.

Hepatic carcinoma is one of the most common cancers in the world, with a high incidence. Emodin is an anthraquinone derived from Polygonum multiflorum Thunb, possessing anti-cancer activity. The purpose of this study is to investigate the anti-cancer effect of different dosages of emodin on HepG2 cells using a 1 H NMR based metabolic approach complemented with qRT-PCR and flow cytometry to identify potential markers and discover the targets to explore the underlying mechanism. Emodin can dose-dependently inhibit the growth of HepG2 cells, perturb cell cycle progression, down-regulate the expression of genes and proteins related to glycolysis, and trigger intracellular ROS generation. Orthogonal signal correction partial least-squares discriminant analysis (OSC-PLS-DA) and correlation network analysis of the 1 H NMR data showed significant changes in many endogenous metabolites after emodin exposure concerning oxidative stress and disturbances in amino acid and energy metabolism. These findings are helpful to understand the anti-cancer mechanism of emodin and provide a theoretical basis for its future application and development.

We report a rationally designed two-step method to fabricate self-supported Ni 3 S 2 nanosheet arrays. We first used 2-methylimidazole (2-MI), an organic molecule commonly served as organic linkers in metal-organic frameworks (MOFs), to synthesize an α-Ni(OH) 2 nanosheet array as a precursor, followed by its hydrothermal sulfidization into Ni 3 S 2 . The resulting Ni 3 S 2 nanosheet array demonstrated superior supercapacitance properties, with a very high capacitance of about 1,000 F g -1 being delivered at a high current density of 50 A g -1 for 20,000 charge-discharge cycles. This performance is unparalleled by other reported nickel sulfide-based supercapacitors and is also advantageous compared to other nickel-based materials such as NiO and Ni(OH) 2 . An asymmetric supercapacitor was then established, exhibiting a very stable capacitance of about 200 F g -1 at a high current density of 10 A g -1 for 10,000 cycles and a surprisingly high energy density of 202 W h kg -1 . This value is comparable to that of the lithium-ion batteries, i.e., 180 W h kg -1 . The potential of the material for practical applications was evaluated by building a quasi-solid-state asymmetric supercapacitor which showed good flexibility and power output, and two of these devices connected in series were able to power up 18 green light-emitting diodes.