bluuebunny/crossref_metadata_2025 huggingface dataset:
Single‐Crystal Semiconductors with Narrow Band Gaps for Solar Water Splitting
Authors: Wang Tuo , Gong Jinlong
Published: July 2015

Solar water splitting provides a clean and renewable approach to produce hydrogen energy. In recent years, single‐crystal semiconductors such as Si and InP with narrow band gaps have demonstrated excellent performance to drive the half reactions of water splitting through visible light due to their suitable band gaps and low bulk recombination. This Minireview describes recent research advances that successfully overcome the primary obstacles in using these semiconductors as photoelectrodes, including photocorrosion, sluggish reaction kinetics, low photovoltage, and unfavorable planar substrate surface. Surface modification strategies, such as surface protection, cocatalyst loading, surface energetics tuning, and surface texturization are highlighted as the solutions.
All‐Carbon [3+3] Oxidative Annulations of 1,3‐Enynes by Rhodium(III)‐Catalyzed CH Functionalization and 1,4‐Migration
Authors: Burns David J. , Best Daniel , Wieczysty Martin D. , Lam Hon Wai
Published: July 2015

1,3‐Enynes containing allylic hydrogens cis to the alkyne function as three‐carbon components in rhodium(III)‐catalyzed, all‐carbon [3+3] oxidative annulations to produce spirodialins. The proposed mechanism of these reactions involves the alkenyl‐to‐allyl 1,4‐rhodium(III) migration.
Room‐Temperature, Strain‐Tunable Orientation of Magnetization in a Hybrid Ferromagnetic Co Nanorod–Liquid Crystalline Elastomer Nanocomposite
Authors: Riou Ophélie , Lonetti Barbara , Tan Reasmey P. , Harmel Justine , Soulantica Katerina , Davidson Patrick , Mingotaud Anne‐Françoise , Respaud Marc , Chaudret Bruno , Mauzac Monique
Published: July 2015

Hybrid nanocomposites based on magnetic nanoparticles dispersed in liquid crystalline elastomers are fascinating emerging materials. Their expected strong magneto‐elastic coupling may open new applications as actuators, magnetic switches, and for reversible storage of magnetic information. We report here the synthesis of a novel hybrid ferromagnetic liquid crystalline elastomer. In this material, highly anisotropic Co nanorods are aligned through a cross‐linking process performed in the presence of an external magnetic field. We obtain a highly anisotropic magnetic material which exhibits remarkable magneto‐elastic coupling. The nanorod alignment can be switched at will at room temperature by weak mechanical stress, leading to a change of more than 50 % of the remnant magnetization ratio and of the coercive field.
Coupling Mo2C with Nitrogen‐Rich Nanocarbon Leads to Efficient Hydrogen‐Evolution Electrocatalytic Sites
Authors: Liu Yipu , Yu Guangtao , Li Guo‐Dong , Sun Yuanhui , Asefa Tewodros , Chen Wei , Zou Xiaoxin
Published: July 2015

In our efforts to obtain electrocatalysts with improved activity for water splitting, meticulous design and synthesis of the active sites of the electrocatalysts and deciphering how exactly they catalyze the reaction are vitally necessary. Herein, we report a one‐step facile synthesis of a novel precious‐metal‐free hydrogen‐evolution nanoelectrocatalyst, dubbed Mo2C@NC that is composed of ultrasmall molybdenum carbide (Mo2C) nanoparticles embedded within nitrogen‐rich carbon (NC) nanolayers. The Mo2C@NC hybrid nanoelectrocatalyst shows remarkable catalytic activity, has great durability, and gives about 100 % Faradaic yield toward the hydrogen‐evolution reaction (HER) over a wide pH range (pH 0–14). Theoretical calculations show that the Mo2C and N dopants in the material synergistically co‐activate adjacent C atoms on the carbon nanolayers, creating superactive nonmetallic catalytic sites for HER that are more active than those in the constituents.
Poly(p‐phenylenediethynylene phosphane): A Phosphorus‐Containing Macromolecule that Displays Blue Fluorescence Upon Oxidation
Authors: Rawe Benjamin W. , Gates Derek P.
Published: July 2015

Despite the challenges associated with their synthesis, hybrid inorganic–organic polymers featuring heavier main‐group elements spaced by π‐conjugated organic functionalities have garnered considerable recent attention due to their chemical functionality and novel photophysical properties. We have succeeded in the preparation of an unprecedented organophosphorus polymer possessing functional phosphane‐di‐yne moieties in the main chain. Namely, poly(p‐phenylenediethynylene phosphane) (PPYP) is prepared using a nickel(II)‐catalyzed PC bond‐forming reaction. The hexyl‐substituted PPYPs are solution processible and have been thoroughly characterized (molecular weight, Mw, ca. 104 Da vs. polystyrene; degree of polymerization, DP, ca. 10). Remarkably, although PPYP shows very weak emission upon irradiation with UV light, its oxide shows blue “turn‐on” fluorescence. The present discovery bridges the areas of main‐group and polymer science and opens the door to a new class of σ‐π‐conjugated macromolecules with unique chemical functionality.
Synthesis of a Tetrabenzotetraaza[8]circulene by a “Fold‐In” Oxidative Fusion Reaction
Authors: Chen Fengkun , Hong Yong Seok , Shimizu Soji , Kim Dongho , Tanaka Takayuki , Osuka Atsuhiro
Published: July 2015

Tetrabenzotetraaza[8]circulene (1) has been synthesized in good yield by a “fold‐in” oxidative fusion reaction of a 1,2‐phenylene‐bridged cyclic tetrapyrrole. X‐ray diffraction analysis of 1 has revealed a planar square structure with a central cyclooctatetraene (COT) core that shows little alternation of the bond lengths. Despite these structural features, 1 shows aromatic‐like character, such as sharp absorption bands, high fluorescence quantum yields (ΦF=0.55 in THF), and a single exponential fluorescence decay with τF=3.8 ns. These observations indicate a dominant contribution of an [8]radialene‐like π conjugation and hence aromatic character of the local aromatic segments in 1.
Design of Decorin‐Based Peptides That Bind to Collagen I and their Potential as Adhesion Moieties in Biomaterials
Authors: Federico Stefania , Pierce Benjamin F. , Piluso Susanna , Wischke Christian , Lendlein Andreas , Neffe Axel T.
Published: July 2015

Mimicking the binding epitopes of protein–protein interactions by using small peptides is important for generating modular biomimetic systems. A strategy is described for the design of such bioactive peptides without accessible structural data for the targeted interaction, and the effect of incorporating such adhesion peptides in complex biomaterial systems is demonstrated. The highly repetitive structure of decorin was analyzed to identify peptides that are representative of the inner and outer surface, and it was shown that only peptides based on the inner surface of decorin bind to collagen. The peptide with the highest binding affinity for collagen I, LHERHLNNN, served to slow down the diffusion of a conjugated dye in a collagen gel, while its dimer could physically crosslink collagen, thereby enhancing the elastic modulus of the gel by one order of magnitude. These results show the potential of the identified peptides for the design of biomaterials for applications in regenerative medicine.
Geometrical Dissipativity‐Based Output Synchronization of Discrete Dynamical Networks with Non‐Identical Nodes
Authors: Li Chensong , Zhao Jun
Published: July 2015

In this paper, we investigate the generalized output synchronization problem for discrete dynamic networks with non‐identical nodes. We consider two cases: output synchronization for fixed topology and arbitrary switching topology. For the first case, we establish several criteria for generalized output synchronization using the geometrical dissipativity property. For the other case, we present a LaSalle invariance principle for discrete switched systems, based on which criteria for generalized output synchronization under arbitrary switching topology are given. Finally, an example is provided to illustrate the effectiveness of the main results.
The quest for restoring hearing: Understanding ear development more completely
Authors: Jahan Israt , Pan Ning , Elliott Karen L. , Fritzsch Bernd
Published: July 2015

Neurosensory hearing loss is a growing problem of super‐aged societies. Cochlear implants can restore some hearing, but rebuilding a lost hearing organ would be superior. Research has discovered many cellular and molecular steps to develop a hearing organ but translating those insights into hearing organ restoration remains unclear. For example, we cannot make various hair cell types and arrange them into their specific patterns surrounded by the right type of supporting cells in the right numbers. Our overview of the topologically highly organized and functionally diversified cellular mosaic of the mammalian hearing organ highlights what is known and unknown about its development. Following this analysis, we suggest critical steps to guide future attempts toward restoration of a functional organ of Corti. We argue that generating mutant mouse lines that mimic human pathology to fine‐tune attempts toward long‐term functional restoration are needed to go beyond the hope generated by restoring single hair cells in postnatal sensory epithelia.
Synthesis of 4‐(2‐Amino)ethoxy‐3′,4′‐dihydroxychalcones and Their Antioxidant and Cytotoxic Effects on Human Tumor Cells
Authors: Kim Hyoung Ja , Kim Seung Hwan , Lee Young Hun , Kim Dong Woon , Mo Kilwoong , Kim Hye Jin , Park Sang Hoon , Jin Changbae , Kim Nam‐Jung , Lee Yong Sup
Published: July 2015

Recently, many reports revealed that there are close correlations between antioxidant and anticancer activities of compounds. In this study, we designed 4‐hydroxy‐3′,4′‐dihydroxychalcone (2) as a ring‐opened analog of luteolin, which has been known to possess both antioxidant and anticancer activities, and then introduced aminoethyl moieties to this chalcone structure to increase water solubility by transforming into HCl salts. Synthesized aminoalkyl‐substituted chalcones 3a–3d showed potent antioxidant activities in three different assay systems and anticancer activities against four tumor cell lines tested.
Synthesis of Benzo[a]carbazoles from 2‐Arylindoles via a Sequential Propargylation, Propargyl‐Allenyl Isomerization, and 6π‐Electrocyclization
Authors: Lim Jin Woo , Kim Se Hee , Kim Jimin , Kim Jae Nyoung
Published: July 2015

An efficient two‐step synthetic approach of benzo[a]carbazoles from 2‐arylindoles has been developed. The first step is a propargylation of 2‐arylindoles at the 3‐position catalyzed by montmorillonite K‐10 in benzene. The second step is 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU)‐catalyzed sequential propargyl‐allenyl isomerization and a concomitant 6π‐electrocyclization process involving two aromatic π‐bonds.
Synthesis and Characterization of Vapor‐grown Si/CNF and Si/PC/CNF Composites Based on Co–Cu Catalysts
Authors: Park Eun‐Sil , Choi Jong‐Ha , Lee Chang‐Seop
Published: July 2015

We report a study on the synthesis and structural characteristics of Si/carbon nanofiber (CNF) and Si/PC/CNF composites. CNFs were synthesized by the chemical vapor deposition using Co and Cu catalysts at a Co:Cu ratio of 6:4. This study focused on the fabrication processes of Si/PC/CNF composites to confirm the contact of Si particles with CNFs. The CNF composites on Si particles were prepared on the basis of the following two processes—Sample 1: CNFs were grown on a simple mechanical mixture of Si particles and catalysts; and Sample 2: CNFs were grown on the surface of pyrolytic carbon‐coated Si particles. The morphology and composition of the Si/CNF composites were analyzed by scanning electron microscope and energy dispersive spectroscopy measurements. Physical properties were investigated using X‐ray diffraction, Raman, X‐ray photoelectron spectroscopy, and thermogravimetric analysis, and the specific surface area was measured by Brunauer, Emmett and Teller. Consequently, pyrolytic carbon coating on the surface of Si particles showed the ability to increase the contact of CNFs to the silicon particles. The resulting pyrolytic carbon‐coated Si/CNF (Si/PC/CNF) composite also demonstrated better crystallizability compared with the Si/CNF composite prepared through the first method.
Direct Synthesis of Hydrogen Peroxide from Hydrogen and Oxygen over Pd‐supported Metal‐Organic Framework Catalysts
Authors: Chung Young‐Min , Lee Yu‐Ri , Ahn Wha‐Seung
Published: July 2015

Pd‐supported metal‐organic framework (MOF) catalysts have been applied for the direct synthesis of H2O2
from H2
and O2
under intrinsically safe and noncorrosive reaction conditions. The catalytic performance was strongly governed by the properties of the support materials, and the Brønsted acid sites newly introduced on the organic linkers of MOF were proven to be more effective than the Lewis acid sites on the open metal sites in enhancing the H2O2
formation and suppressing its decomposition. Pd/MIL‐101‐SO3H was highly efficient in promoting the reaction owing to the contribution from the strong acidity and highly porous nature of the robust MOF support used. The hydrogen peroxide productivity of Pd/MIL‐101‐SO3H catalyst reached 361 mmol H2O2
mmol/Pd/h, which was 2.3 or 1.7 times higher than that of the conventional Pd/HBEA (SAR = 25) or Pd/sulfonated resin catalyst, respectively. This result clearly demonstrates the promising potential of MOF as a solid acid support material.
Preparation of Porous Carbons Under Basic Condition by Soft Template Method for Carbon Capture
Authors: Park Seo Kyoung , Han Tae Youl , Lee Je Seung
Published: July 2015

Microporous and mesoporous carbons have been prepared by a soft template method using 2,2′‐biphenol as a precursor. The porosity of carbons could be controlled by varying the amount of block copolymer used as a soft template and the specific surface areas measured were as high as 648 m2/g with a pore volume of 0.43 cm3/g. The surface areas of prepared carbons were further increased up to 1778 m2/g with a pore volume of 0.75 cm3/g after heat treatment under ammonia gas environment. Although the prepared pristine carbons had lower surface areas than commercial activated carbon, they exhibited higher carbon dioxide (CO2
) adsorption capacity. The CO2
adsorption capacity of ammonia‐activated carbons further increased up to 2.98 mmol/g at ambient temperature and pressure.
Application of Mesoporous Silica Foam for Immobilization of Salen Complexes in Chiral Intermediates Synthesis
Authors: Jeon Hoon‐Gi , Choi Seong Dae , Jeon Sang Kwon , Park Geun Woo , Yang Jin Young , Kim Geon‐Joong
Published: July 2015

A route to synthesize porous materials with a hierarchical micro/meso/macroscopic pore system was investigated. Meso/macroporous monolithic silica foams with a large pore size could be fabricated from a mixture of monodispersed PMMA beads and SBA‐15, ‐16 sol solutions. The size, bulk shape and density of the mesoporous monolithic foam could be controlled by the container and the heat treatment temperature. Drying at temperatures higher than 300 °C resulted in an expansion of the SBA silica sol and its solidification to form the mesoporous foams. In contrast, only a dense silica monolith was obtained after full evaporation of the solvent at room temperature without releasing the foam structure in the monolithic body. A large fraction of macroporosity in three dimensions was formed in the monolith body, and the remaining silica walls exhibited uniform mesoporosity. Hydrolytic and phenolic ring‐opening of epoxides were performed successfully using chiral (salen)Co‐BF3 complex‐immobilized catalysts in the packed bed of a continuous flow system. Very high catalytic activity with desirable enantioselectivity was obtained in asymmetric catalysis.
Kinetic and Mechanistic Studies on Quinuclidinolysis of Y‐substituted‐Phenyl Picolinates: Effect of Amine Nature on Reactivity and Transition‐State Structure
Authors: Um Ik‐Hwan , Kim Min‐Young , Kang Yeseul
Published: July 2015

Second‐order rate constants (k
N) have been measured spectrophotometrically for reactions of Y‐substituted‐phenyl picolinates (7a–7i) with a series of quinuclidines in 80 mol% H2O/20 mol% DMSO at 25.0 ± 0.1 °C. The Brønsted‐type plot for the reactions of 7a–7i with quinuclidine is linear with β
lg = −0.80. The Yukawa‐Tsuno plot exhibits an excellent linear correlation with ρY = 2.37 and r = 0.52, indicating that a negative charge develops partially on the O atom of the leaving group in the rate‐determining transition state (TS). The Brønsted‐type plot for the reactions of 2‐chloro‐4‐nitrophenyl picolinate (7a) with a series of quinuclidines is also linear with β
nuc = 0.83. Thus, it was concluded that the reactions proceed through a stepwise mechanism, in which expulsion of the leaving group occurs in the rate‐determining step. Comparison of the current kinetic data with those reported previously for the corresponding reactions with piperidine revealed that quinuclidine is ca. 102‐fold less reactive than piperidine. This is in contrast to the reports that quinuclidines are more reactive than isobasic secondary amines toward diaryl carbonates and related esters. Effects of amine nature on reactivity and TS structures are discussed.
Preparation of Zinc Oxide Nanoparticles at Low Temperature Using New Organometallic Zinc Carbamate Precursor
Authors: Kim Kyung‐A , Cha Jae‐Ryung , Yun Sang‐Woo , Gong Myoung‐Seon
Published: July 2015

Zinc oxide nanoparticles (ZnO NPs) were synthesized in 2‐methoxyethanol without assistance of base, surfactant, template, etc., at relatively low temperature of 125 °C, by a single‐step thermolysis. Thermolysis of Zn(IBC)2led to the formation of almost pureZnO NPsof various shapes. Transmission electron microscope (TEM) images showed that oleic acid–stabilizedZnO NPswith diameters of 10–20 nm were well dispersed in organic solvent. ResultingZnOwas characterized byUV–vis spectroscopy, Raman spectroscopy, X‐ray photoelectron spectroscopy, X‐ray powder diffraction, scanning electron microscopy, and high‐resolutionTEM. Room temperature photoluminescence (PL) spectra ofZnO NPsannealed at different temperatures showed different emission peaks in the range of 400–700 nm. TheZnO NPsprepared at 125 °C in air caused a further shift of the defect‐relatedPLmaximum toward the lower energy range (red‐light emission) in comparison with the one prepared at 125 °C in 2‐methoxyethanol.
Synthesis and Shape Control of Uniform Polymer Microparticles by Tailored Adsorption of Poly(ethylene oxide)‐b‐Poly(ε‐caprolactone) Copolymer
Authors: Acter Shahinur , Cho Jangwoo , Kim Jeong Won , Byun Aram , Park Kyoung‐Ho , Kim Jin Woong
Published: July 2015

This paper introduces a straightforward and robust polymerization method for the synthesis of uniform polymer microparticles having controlled surface chemistry as well as tailored particle shapes. Uniform polystyrene (PS) microparticles are produced by dispersion polymerization, in which amphiphilic poly(ethylene oxide)‐b‐poly(ε‐caprolactone) (PEO‐b‐PCL) copolymers anchor on to the growing polymer particles and stabilize them by steric repulsion. We have observed that, when PEO‐b‐PCL copolymers are incorporated at the proper concentration range, the total number of particles remains unchanged after the formation of primary particles, which is essential for maintaining size uniformity. Otherwise, nonuniform PS microparticles are produced mainly as a result of the coagulation or secondary formation of particles. To show the diversity of our particle synthesis technology, shape‐controlled microparticles, such as dimples and Janus particles, are also produced by using temperature‐mediated swelling and phase separation. Finally, we show that PEO‐b‐PCL copolymers play a key role in regulating the surface wettability of the seed particles, thereby facilitating the formation of anisotropic microparticles.
Determination of Fluoride Concentration in Antarctic Krill (Euphausia superba) using Dielectric Spectroscopy
Authors: Lu Jianfeng , Qi Lina , Guo Wen , Song Yishan , Jung Yong An , Cheng Yu‐dong , Jin Yinzhe
Published: July 2015

The concentration of fluoride in Antarctic krill (Euphausia superb) was investigated using a coaxial probe method based on dielectric properties in the 0.3–10 GHz frequency range. A quantitative relationship between the fluoride concentration in the aqueous solution and the dielectric loss at 0.3 GHz was also established with a regression coefficient over 0.98. The concentrations of fluoride in fresh and dried krill samples with different krill positions, such as shell and meat, were determined. The detected value agrees well with that determined using other methods, such as fluoride ion‐selective electrode (ISE) and potassium permanganate titration (PPT). The fluoride concentrations in fresh krill were 0.0127, 0.0133, and 0.0152 mg/mL using dielectric spectroscopy, PPT, and ISE, respectively. These results show that the proposed dielectric loss technique is suitable and effective for determining fluoride content in Antarctic krill.
Kinetic Study on Alkaline Hydrolysis of Y‐substituted Phenyl X‐substituted Benzenesulfonates: Effects of Changing Nucleophile from Azide to Hydroxide Ion on Reactivity and Transition‐State Structure
Authors: Moon Ji‐Hyun , Kim Min‐Young , Han So‐Yeop , Um Ik‐Hwan
Published: July 2015

Second‐order rate constants () for alkaline hydrolysis of 2,4‐dinitrophenyl X‐substituted benzenesulfonates (1a–1f) and Y‐substituted phenyl 4‐nitrobezenesulfonates (2a–2g) have been measured spectrophotometrically. Comparison of with the values reported previously for the corresponding reactions with has revealed that OH
 is only 103‐fold more reactive than , although the former is 11 pK
a units more basic than the latter. The Yukawa–Tsuno plot for the reactions of 1a–1f results in an excellent linear correlation with ρ
X = 2.09 and r = 0.41. The Brønsted‐type plot for the reactions of 2a–2g is linear with β
lg = −0.51, which is typical for reactions reported to proceed through a concerted mechanism. The Yukawa–Tsuno plot for the reactions of 2a–2g exhibits excellent linearity with ρ
Y = 1.85 and r = 0.25, indicating that a partial negative charge develops on the O atom of the leaving group in the transition state. Thus, the alkaline hydrolysis of 1a–1f and 2a–2g has been concluded to proceed through a concerted mechanism. Comparison of the ρ
X and β
lg values for the reactions with ions suggests that the reactions with hydroxide ion proceed through a tighter transition‐state structure than those with azide ion.
Photoluminescence and Structural Properties of Tin‐doped ZnO Thin Films Deposited by Sol–Gel Dip Coating
Authors: Kim Younggyu , Leem Jae‐Young
Published: July 2015

Tin‐doped ZnO (TZO) thin films with various tin concentrations (0, 1, 2, 3, 4, and 5 atomic percent [at. %]) are prepared by the sol–gel dip‐coating method. The doping effects of tin on the structural and optical properties of the TZO thin films are investigated. All the samples have a granular structure consisting of small particles and exhibited a preferred c‐axis orientation. The transmittance and optical band gap of the TZO thin films increase at relatively low tin concentrations of 1–2 at. %, whereas they decrease at higher concentrations of 3–5 at. %. The ratio of near‐band‐edge emission intensity to deep‐level emission intensity significantly increases with increasing tin concentrations from 0 to 4 at. %. In addition, low‐temperature photoluminescence for undoped and 4 at. % TZO thin films are measured at 12 K to thoroughly analyze the effects of tin doping.
Biochemical and Structural Characterization of Recombinant Human Endogenous Retrovirus‐R
Authors: Park So Young , Jeong Mi Suk , Kim Heui‐Soo , Jang Se Bok
Published: July 2015

Human endogenous retroviruses (HERVs) comprise approximately 8% of the human genome, and the majority ofHERVsexist in truncated form with multiple stop codons, insertions, and deletions. BecauseHERVscontribute to genome instability via mutation events such as rearrangement and retrotransposition, it has been proposed that they may play a role in human pathology. Although the role of theenvgene expression of full‐length endogenous retrovirus (HERV)‐R has been investigated in various human tissues and cancer cells, there have been no studies of solubleHERV‐R protein or structural characterizations of the protein expressed inEscherichia colito date. Full‐lengthHERV‐R is composed of a surface (SU) domain and a transmembrane (TM) domain. In this study, we successfully expressed and purified theTMregion ofHERV‐R with high solubility, and then modeled the three‐dimensional structure of theHERV‐RTMandSUdomains by homology modeling based on the structure of the Ebola virus membrane fusion subunit and the feline leukemia virus receptor‐binding domain. Furthermore, we found that theSUdomain was bound toRNA. Our results will enable the production of recombinantHERV‐R protein in large quantities and facilitate future functional and structural analyses ofHERV‐R.
Reduction of Graphene Oxide and its Effect on Square Resistance of Reduced Graphene Oxide Films
Authors: Hou Zhaoxia , Zhou Yin , Li Guangbin , Wang Shaohong , Wang Meihan , Hu Xiaodan , Li Siming
Published: July 2015

Graphite oxide was prepared via the modified Hummers’ method and graphene via chemical reduction. Deoxygenation efficiency of graphene oxide was compared among single reductants including sodium borohydride, hydrohalic acids, hydrazine hydrate, and vitamin C. Two‐step reduction of graphene oxide was primarily studied. The reduced graphene oxide was characterized by XRD, TG, SEM, XPS, and Raman spectroscopy. Square resistance was measured as well. Results showed that films with single‐step N2H4
reduction have the best transmittance and electrical conductivity with square resistance of ~5746 Ω/sq at 70% transmittance. This provided an experimental basis of using graphene for electronic device applications.
Binding of Imidazole Stabilizes Low‐spin State of Heme Iron in Dual‐Substrate‐Specific Rice Allene Oxide Synthase‐1
Authors: Yoeun Sereyvath , Sukhanov Andrey , Han Oksoo
Published: July 2015

Kinetic studies have indicated that imidazole is a competitive inhibitor of rice allene oxide synthase‐1 with K
i of 34.9, 14.3, 40.3, and 23.3 mM for 13(S)‐HPODE, 13(S)‐HPOTE, 9(S)‐HPODE, and 9(S)‐HPOTE as substrates, respectively. Imidazole‐free rice allene oxide synthase‐1 has a Soret absorbance maximum at 393 nm and occupied high‐spin (g = 6.0) and low‐spin (g = 2.39, 2.24, 1.93) states in the ratio 1:10, as detected by EPR spectroscopy, while in the presence of imidazole the occupancy of the low‐spin state increased to 100%. The results support the hypothesis that imidazole competes with the substrate of allene oxide synthase‐1 for binding to the sixth position of heme iron(III) and that binding of imidazole stabilizes the low‐spin state. The role of detergent binding and implications for the mechanism by which allene oxide synthase‐1 cleaves the RO‐OH bond are discussed.
Identification and Quantification of Phthalates, PAHs, Amines, Phenols, and Metals in Tattoo
Authors: Lim Hyun‐Hee , Shin Ho‐Sang
Published: July 2015

The determination methods of polycyclic aromatic hydrocarbons (PAHs), phthalates, primary amines, phenols, and metals in tattoo dyes have been optimized and validated using gas chromatography‐mass spectrometry, liquid chromatography‐tandem mass spectrometry, and inductively coupled plasma‐mass spectrometry. Twelve PAHs, 3 phthalates, 4 amines, and 15 metals were identified and quantified in 16 different tattoo dyes purchased from shops in the Republic of Korea. Phenols were not detected in any sample. The total PAHs in six inks and benzo(a)pyrene in one tattoo ink exceeded the legal limit set by the Council of Europe, and their maximum detected concentrations were about 10 and 5 times the limits of the compounds, respectively. 3,3′‐Dichlorobenzidine and o‐anisidine, which should not be present in tattoo inks by Resolution ResAP (2008) of the Council of Europe, were detected in tattoo inks. Also, Cd, Pb, Cu, Ba, Ni, Sb, Zn, and As exceeded the limits. These hazardous compounds should be controlled to the lowest possible concentrations in the raw materials and the production procedure of tattoo ink.
Systematically Controlled Pore System of Ordered Mesoporous Carbons Using Phosphoric Acid as the In situ Generated Catalysts for Carbonization and Activation
Authors: Jin Xing , Lee Chang Hyun , Kim Jin Hoe , You Dae Jong , Pak Chanho , Shon Jeong Kuk , Kim Ji Man
Published: July 2015

We report on a facile synthesis of the ordered mesoporous carbon (OMC) materials with systematically controlled microporosity and mesoporosity simultaneously through the nano‐replication route using phosphoric acid as the acid catalyst and activation agent. The use of phosphoric acid affects the pore structures of OMC materials, such as the formation of numerous micropores by activation of the carbon framework and the enlargement of mesopores by spontaneous phase separation during the carbonization. The mesopore sizes, surface areas, total pore volumes, and micropore volumes of the OMC materials are highly dependent on the phosphoric acid content and can be systematically controlled in the range 3.7–7.5 nm, 1027–2782 m2 g–1, 1.12–3.53 cm3 g–1 and 0.34–0.95 cm3 g–1, respectively. OMC materials with systematically controlled pore structures were successfully synthesized using phosphoric acid as the carbonization catalyst and mesoporous silica materials with cubic Ia3d and 2‐D hexagonal mesostructures as the templates. The phosphoric acid in the synthesis of ordered mesoporous carbon materials acts as the chemical activating agent for micropore generation of the carbon framework and pore‐expanding agent for controlling of mesopore size, in addition to functioning as the acid catalyst. The present synthesis pathway is very useful for preparing OMC materials with tunable mesopore sizes and well‐developed microporosities at the same time.
The snapping medial antebrachial cutaneous nerve
Authors: Cesmebasi Alper , O'driscoll Shawn W. , Smith Jay , Skinner John A. , Spinner Robert J.
Published: July 2015

Snapping elbow is a well‐known condition where elbow flexion and extension elicits a painful, popping sensation. The most frequent etiology is anterior dislocation of the ulnar nerve over the medial epicondyle. Four patients (3 females and 1 male) presented with complaints of a popping sensation in the elbow, pain over the medial aspect of the forearm, and ulnar neuritis. All patients underwent preoperative dynamic ultrasound and surgical exploration of the medial elbow. Intraoperatively, snapping of the MABC over the medial epicondyle was discovered in all four patients. In three patients, there was abnormal displacement of the medial triceps and ulnar nerve: in two of these, both structures dislocated over the medial epicondyle and in one patient both structures subluxated. In each case, the MABC was decompressed (n = 1) and transposed (n = 3), and in three cases, the medial triceps and ulnar nerve were addressed as well. Symptomatic improvement was achieved in all cases. Retrospective review of the ultrasound revealed the snapping MABC, though it was less effective prospectively in the cases when snapping MABC was not suspected. In conclusion, snapping of the MABC broadens the spectrum of disorders that results in snapping elbow. To our knowledge, we are unaware of prior reports of this entity. Clin. Anat. 28:872–877, 2015. © 2015 Wiley Periodicals, Inc.
Beauty or function? How different mass customization toolkits affect customers' process enjoyment
Authors: Schnurr Benedikt , Scholl‐Grissemann Ursula
Published: July 2015

Although it is widely acknowledged that mass customization (MC) increases both company and customer value, the research has neglected the possible effects of different MC toolkits on customer responses. In this study, we investigate the influence of different MC toolkits on customers' process enjoyment by manipulating the extent to which those toolkits allow customers to customize a product's functional attributes (functional MC toolkits), aesthetic attributes (aesthetic MC toolkits), or both (supreme toolkits). In addition, we examine the moderating effect of customers' ability to customize. The results of two experimental studies show that regardless of their ability to customize, customers' process enjoyment is higher with an aesthetic MC toolkit than with a functional MC toolkit. For customers with a high ability to customize, process enjoyment with a supreme toolkit is higher than process enjoyment with an aesthetic toolkit, whereas no differences exist for customers with a low ability to customize. This research contributes significantly to the existing literature on mass customization and provides managers with insights on how to more effectively develop and implement MC toolkits. Copyright © 2015 John Wiley & Sons, Ltd.
Catalytic Reduction by Quasi‐Homogeneous Gold Nanoclusters in the Liquid Phase
Authors: Chong Hanbao , Zhu Manzhou
Published: July 2015

Reduction reactions play significant roles in industrial manufacture, and supported metal nanoparticles (NPs) show great prospect for mass production. The gold NPs have achieved expanding progress in selective reduction in recent years and will lead to a hot issue in the future. However, the designing of efficient catalysts is currently quite challenging because of the lack of systematic understandings on the fundamentals of the catalytic efficiency. Fortunately, tremendous advances can be expected with the aid of quasi‐homogeneous NPs. This review highlights the unsupported gold NPs or nanoclusters (NCs) catalyzed reduction reactions, which include single‐electron‐transfer catalysis, selective hydrogenation of carbonyl and nitro groups. The tentative catalytic mechanism and the size‐dependence of gold nanocatalyst have also been discussed in this review.
Direct Immobilization of Ru‐Based Catalysts on Silica: Hydrogen Bonds as Non‐Covalent Interactions for Recycling in Metathesis Reactions
Authors: Nasrallah Houssein , Dragoe Diana , Magnier Caroline , Crévisy Christophe , Mauduit Marc , Schulz Emmanuelle
Published: July 2015

The commercially available M71‐SIPr ruthenium precatalyst was deposited on silica, with the aim to develop a simple procedure for catalyst recovery in metathesis reactions. Various spectroscopic analyses revealed that the impregnation resulted from hydrogen bonding interactions, specifically with the carbonyl group of the trifluoroacetamide moiety of the complex. These interactions were, furthermore, responsible for catalytic improvement through a facilitated release of the active ruthenium species. The silica‐supported complex proved to be an efficient catalyst for the promotion of various olefin metathesis reactions in a multisubstrate procedure. The catalytic material was easily recovered by simple filtration and delivered the targeted products in high yield for seven consecutive runs.
Preparation of Nitrogen‐Doped Carbon from Polyacrylonitrile and its Application as a Solid‐Base Catalyst
Authors: Fujita Shin‐ichiro , Katagiri Ayaka , Watanabe Hiroyuki , Asano Sayaka , Yoshida Hiroshi , Arai Masahiko
Published: July 2015

N‐doped carbon (N carbon) materials were prepared from a commercial polyacrylonitrile (PAN) by calcination and subsequent ammoxidation and these were used for a model reaction of Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate. The catalytic activity of the calcined PAN for the reaction was very low, but it was greatly enhanced by the ammoxidation and the enhancement depended on both the calcination and ammoxidation temperatures. X‐ray photoelectron spectra indicated the presence of pyridine‐type and pyrrole‐/pyridone‐type N species and the amount of the former N species was well correlated with the catalytic activity. It was suggested that the presence of pyridine‐type N in the graphene structure is significant for the emergence of the catalytic activity. The most active N‐carbon catalyst prepared in the present study was much more active than solid‐based catalysts reported so far including N carbon derived from activated carbon, N‐doped carbon nanotubes, and a few metal oxide based catalysts.
Selective Hydrogenation of Phenol to Cyclohexanone over Pd–HAP Catalyst in Aqueous Media
Authors: Xu Guangyue , Guo Jianhua , Zhang Ying , Fu Yao , Chen Jinzhu , Ma Longlong , Guo Qingxiang
Published: July 2015

The production of pure cyclohexanone under mild conditions over catalysts with high reactivity, selectivity, compatibility, stability, and low cost is still a great challenge. Here we report a hydroxyapatite‐bound palladium catalyst (Pd–HAP) to demonstrate its excellent performance on phenol hydrogenation to cyclohexanone. Based on catalyst characterization, the Pd nanoclusters (≈0.9 nm) are highly dispersed and bound to phosphate in HAP. Only basic active sites on HAP surface are detected. At 25 °C and ambient H2 pressure in water, phenol can be 100 % converted into cyclohexanone with 100 % selectivity. This system shows a universal applicability to temperature, pH, solvent, low H2 purity, and pressure. The catalyst reveals high stability to be recycled without deactivation or morphology change; and Pd nano‐clusters barely aggregate even at 400 °C. During the reaction, HAP adsorbs phenol, and Pd nanoclusters activate and spillover H2. The mechanism is also investigated, proposed, and verified.
A One‐Step Biocatalytic Process for (S)‐4‐Chloro‐3‐hydroxybutyronitrile using Halohydrin Dehalogenase: A Chiral Building Block for Atorvastatin
Authors: Wan Nan‐Wei , Liu Zhi‐Qiang , Xue Feng , Shen Zhen‐Yang , Zheng Yu‐Guo
Published: July 2015

(S)‐4‐Chloro‐3‐hydroxybutyronitrile [(S)‐CHBN] was used as a chiral building block for the preparation of atorvastatin. In this study, (R,S)‐epichlorohydrin [(R,S)‐ECH] and 1,3‐dichloro‐2‐propanol (1,3‐DCP) were investigated to prepare (S)‐CHBN by using the halohydrin dehalogenase HheC from Agrobacterium radiobacter AD1. Preparing (S)‐CHBN from (R,S)‐ECH gave a modest enantiomeric excess (ee), whereas by using 1,3‐DCP as the substrate, (S)‐CHBN was obtained with 97.3 % ee after pH optimization. However, a low ee value and low yield of (S)‐CHBN were obtained if the substrate concentration was increased to 10 g L−1. To obtain a higher ee value and yield, 16 mutants were constructed and screened. The variant W249F with improvements in activity and enantioselectivity was identified and applied at a 1,3‐DCP loading of 10 g L−1, which gave (S)‐CHBN in 86 % yield with 97.5 % ee in 1 h. This is the first report of a one‐step biocatalytic process for the preparation of (S)‐CHBN from prochiral 1,3‐DCP.
Electrochemical Properties and Dissolution Mechanism of A2Ni7 Hydrides (A=Y, Gd, La–Sm)
Authors: Puga Beatriz , Joiret Suzanne , Vivier Vincent , Charbonnier Véronique , Guerrouj Habiba , Zhang Junxian , Monnier Judith , Fariaut‐Georges Cécile , Latroche Michel , Goubault Lionel , Bernard Patrick
Published: July 2015

The electrochemical behavior of hydride‐forming A2B7 alloys (Y2Ni7, LaSmNi7, and Gd2Ni7) is investigated in KOH solution. The evolution of the material performance is shown to strongly depend on the A elements. Electrochemical impedance spectroscopy (EIS), SEM observations, XRD, and Raman spectroscopy showed that Y2Ni7 is mainly sensitive to calendar corrosion and decrepitation, whereas LaSmNi7 and Gd2Ni7 are sensitive to the concomitant effect of both cycling and calendar corrosion. It is also shown that the capacity loss of Gd2Ni7 can be ascribed to amorphization on cycling, which is not the case for Y2Ni7. The formation of both an thin oxide film (a few tens of nanometers thick) at the material surface, measured by EIS, and the dissolution products formed during long‐term immersion, analyzed by Raman spectroscopy, is in agreement with the decrease in material activity evaluated by EIS during cycling at different depths of charge.
Apparent Oxygen Uphill Diffusion in La0.8Sr0.2MnO3 Thin Films upon Cathodic Polarization
Authors: Huber Tobias M. , Navickas Edvinas , Friedbacher Gernot , Hutter Herbert , Fleig Jürgen
Published: July 2015

The impact of cathodic bias on oxygen transport in La0.8Sr0.2MnO3 (LSM) thin films was investigated. Columnar‐grown LSM thin films with different microstructures were deposited by pulsed laser deposition. 18O tracer experiments were performed on thin film microelectrodes with an applied cathodic bias of −300 or −450 mV, and the microelectrodes were subsequently analyzed by time‐of‐flight secondary ion mass spectrometry. The 18O concentration in the cathodically polarized LSM microelectrodes was strongly increased relative to that in the thermally annealed film (without bias). Most remarkable, however, was the appearance of a pronounced 18O fraction maximum in the center of the films. This strongly depended on the applied bias and on the microstructure of the LSM thin layers. The unusual shape of the 18O depth profiles was caused by a combination of Wagner–Hebb‐type stoichiometry polarization of the LSM bulk, fast grain boundary transport and voltage‐induced modification of the oxygen incorporation kinetics,
Bipolar Electrochemical Approach with a Thin Layer of Supporting Electrolyte towards the Growth of Self‐Organizing TiO2 Nanotubes
Authors: Saqib Muhammad , Lai Jianping , Zhao Jianming , Li Suping , Xu Guobao
Published: July 2015

We report a new bipolar electrochemical approach for the growth of ordered titanium dioxide nanotubes (NTs), using a thin layer of supporting electrolyte, and the preparation of multiple samples through bipolar electrochemistry in a single wireless run. Our configuration allows the efficient growth of TiO2 NTs in a horizontal direction with low electrolyte consumption, which facilitates heat dissipation. In this simple, rapid, and cost‐effective method, we can also successfully tune the inner and outer diameters of TiO2 NTs to 25–64 nm and 42–85 nm, respectively, with key parameters such as fluoride content, anodization voltage, anodization time, and water content.
Elucidation of the Electrochemical Reaction Mechanism in MFe2O4 (M=Ni, Co) Conversion‐Type Negative Electrode Systems by using In Situ X‐ray Absorption Spectroscopy
Authors: Balachandran Geethu , Dixon Ditty , Bramnik Natalia , Bhaskar Aiswarya , Yavuz Murat , Pfaffmann Lukas , Scheiba Frieder , Mangold Stefan , Ehrenberg Helmut
Published: July 2015

Mixed transition‐metal ferrites with the chemical formula MFe2O4 (M=Co, Ni), synthesized through an inverse co‐precipitation route, were characterized by using scanning electron microscopy and powder X‐ray diffraction, which demonstrate phase‐pure compounds with particle sizes of about 100 nm. Cyclic voltammetry investigations in lithium half‐cells revealed a difference between the first cycle and the following charge–discharge cycles, which is characteristic for conversion‐type electrode systems. To understand the mechanism of the electrochemical reaction in the first cycle, in situ X‐ray absorption spectroscopy was performed during cycling at a charge–discharge rate of C/10. During the first discharge process, the crystalline Co and Ni ferrites undergo reduction. A coexistence of binary metal oxides (CoO/NiO and Fe2O3) and metallic phases were observed during the discharge. At the end of discharge, only the existence of metallic nanoclusters was observed. In the subsequent charging process, Fe was found to undergo complete oxidation in both ferrites. In contrast, almost 60 % of the Co or Ni remained in the metallic state at the end of the charge (end of first cycle). This incomplete oxidation of Co and Ni in the applied voltage range could be the main reason behind the irreversible capacity loss and low coulombic efficiency often reported for these conversion electrode systems.
Phosphorus Nanoparticles Encapsulated in Graphene Scrolls as a High‐Performance Anode for Sodium‐Ion Batteries
Authors: Pei Longkai , Zhao Qing , Chen Chengcheng , Liang Jing , Chen Jun
Published: July 2015

Two composites of phosphorus nanoparticles encapsulated in graphene scrolls (P‐G) and phosphorus nanoparticles loaded on planar graphene sheets (P/G) were successfully prepared and applied as anodes for sodium‐ion batteries. Phosphorus nanoparticles (ca. 100–150 nm) were firstly obtained from commercial red phosphorus by using a simple flotation method. P‐G composites with different phosphorus contents (38.6, 52.2, and 62.1 %) were synthesized through a quick‐freezing process. In addition, the P/G composite with a phosphorus content of 50.8 % was prepared for comparison purposes. As a result, the P‐G composites showed a better performance than the P/G composite. Moreover, the P‐G composite with a phosphorus content of 52.2 % showed the best performance, delivering a capacity of 2355 mAh g−1 in the second cycle and 2172 mAh g−1 after 150 cycles at 250 mA g−1 (with a capacity retention of 92.3 %).
Control of Metal Arrays Based on Heterometallics Masquerading in Heterochiral Aggregations of Chiral Clothespin‐Shaped Complexes
Authors: Naito Masaya , Inoue Ryo , Iida Masayuki , Kuwajima Yuuki , Kawamorita Soichiro , Komiya Naruyoshi , Naota Takeshi
Published: July 2015

Heterometal arrays in molecular aggregations were obtained by the spontaneous and ultrasound‐induced gelation of organic liquids containing the chiral, clothespin‐shaped trans‐bis(salicylaldiminato) d8 transition‐metal complexes 1. Heterometallic mixtures of complexes 1 a (Pd) and 1 b (Pt) underwent strict heterochiral aggregation entirely due to the organic shell structure of the clothespin shape, with no effect of the metal cores. This phenomenon provides an unprecedented means of generating highly controlled heterometallic arrangements such as alternating sequences [(+)‐Pd(−)‐Pt(+)‐Pd(−)‐Pt⋅⋅⋅] as well as a variety of single metal‐enriched arrays (e.g., [(+)‐Pt(−)‐Pd(+)‐Pd(−)‐Pd(+)‐Pd(−)‐Pd⋅⋅⋅] and [(+)‐Pd(−)‐Pt(+)‐Pt(−)‐Pt(+)‐Pt(−)‐Pt⋅⋅⋅]) upon the introduction of an optically active masquerading unit with a different metal core in the heterochiral single‐metal sequence. The present method can be applied to form various new aggregates with optically active Pd and Pt units, to allow 1) tuning of the gelation ultrasound sensitivity based on the different hearing abilities of the metal units; 2) aggregation‐induced chirality transfer between heterometallic species; and 3) aggregation‐induced chirality enhancement. A mechanistic rationale is proposed for these molecular aggregations based on the molecular structures of the units and the morphologies of the aggregates.
Configuration‐Dependent Photoinduced Electron Transfer in Diastereomeric Naphthalene‐Amino‐Naphthalene Triads
Authors: Nuin Edurne , Sastre German , Pischel Uwe , Andreu Inmaculada , Miranda Miguel A.
Published: July 2015

Novel diastereomeric triads containing two naphthalene chromophores have been designed in which an electron‐donating amine moiety is covalently integrated into the connecting bridge. Photophysical studies (steady‐state and time‐resolved fluorescence) in solvents of different polarity have been performed. A remarkable stereodifferentiation in the intramolecular fluorescence quenching was found in acetonitrile. Laser flash photolysis gave rise to naphthalene‐derived radical cations, which were also quenched by the amine with an even higher degree of stereodifferentiation. The results are in agreement with thermodynamic estimations and indicate that photoinduced electron transfer (PET) is the main quenching pathway. Furthermore, theoretical calculations have allowed us to explain the experimentally observed stereodifferentiation in PET quenching.
Synthesis of Diverse N‐Substituted Muramyl Dipeptide Derivatives and Their Use in a Study of Human NOD2 Stimulation Activity
Authors: Chen Kuo‐Ting , Huang Duen‐Yi , Chiu Cheng‐Hsin , Lin Wan‐Wan , Liang Pi‐Hui , Cheng Wei‐Chieh
Published: July 2015

A flexible synthetic strategy toward the preparation of diverse N‐substituted muramyl dipeptides (N‐substituted MDPs) from different protected monosaccharides is described. The synthetic MDPs include N‐acetyl MDP and N‐glycolyl MDP, known NOD2 ligands, and this methodology allows for structural variation at six positions, including the muramic acid, peptide, and N‐substituted moieties. The capacity of these molecules to activate human NOD2 in the innate immune response was also investigated. It was found that addition of the methyl group at the C1 position of N‐glycolyl MDP significantly enhanced the NOD2 stimulating activity.