bluuebunny/crossref_metadata_2025 huggingface dataset:
Redoxaktive NOx‐Liganden in palladiumvermittelten Prozessen
Authors: J. S. Fairlamb Ian
Published: July 2015

Dieser Kurzaufsatz fasst jüngste Arbeiten über redoxaktive (“non‐innocent”) NOx‐Liganden (x=1, 2 oder 3) in ausgewählten Pd‐vermittelten Prozessen, beispielsweise Alken‐ und aromatischen Oxidationen, zusammen. Im Mittelpunkt stehen mechanistische Studien, sowie Betrachtungen zu den Parallelen zwischen neueren Umsetzungen, wie C‐H‐Bindungsaktivierungen und der Wacker‐Oxidation, und früheren Arbeiten zur Funktionalisierung von Aromaten und Alkenen mit PdII‐Salzen.
Biomimetische Selbstheilung
Authors: Diesendruck Charles E. , Sottos Nancy R. , Moore Jeffrey S. , White Scott R.
Published: July 2015

Selbstheilung ist ein natürlicher Vorgang, der allen lebenden Organismen zu eigen ist und eine höhere Lebensspanne sowie die Fähigkeit zur Anpassung an Umgebungsveränderungen mit sich bringt. Inspiriert von dieser evolutionär entwickelten Funktionalität haben Wissenschaftler und Ingenieure synthetische Materialien mit Selbstheilungsvermögen erschaffen. In Anlehnung an mechanisch ausgelöste chemische Vorgänge und die Speicherung und Abgabe flüssiger Reagentien in der Natur wurden neue Materialien mit höherer Lebensspanne entwickelt, die nach Beschädigung ihre mechanische Integrität sowie zusätzliche Funktionen regenerieren können. Dieser Aufsatz beschreibt die Grundlagen dieses aktuellen Gebiets an der Schnittstelle zwischen Chemie, Physik, Material‐ und Ingenieurwissenschaften.
Einkristalline Halbleiter mit kleinen Bandlücken für die solare Wasserspaltung
Authors: Wang Tuo , Gong Jinlong
Published: July 2015

Die Wasserspaltung mittels Sonnenenergie bietet einen sauberen und erneuerbaren Ansatz für die Produktion von Wasserstoff. Einkristalline Halbleiter mit kleinen Bandlücken und geringer Ladungsträgerrekombination, wie Si und InP, erweisen sich als sehr gut geeignet, die Halbreaktionen der Wasserspaltung – die Wasserstoff‐ (HER) und Sauerstoffentwicklung (OER) – unter Einwirkung von sichtbarem Licht zu fördern. Durch die Verwendung dieser Halbleiter als Photoelektroden konnte in jüngster Zeit eine Reihe von Problemen im Zusammenhang mit Photokorrosion, langsamen Reaktionskinetiken, niedrigen Photospannungen und ungünstigen planaren Substratoberflächen gelöst werden. Dieser Kurzaufsatz fasst den aktuellen Stand der Forschungen zusammen, mit Schwerpunkt auf Oberflächenmodifizierungsstrategien, wie z. B. Oberflächenschützung, Beladung mit Kokatalysatoren, Abstimmung der Oberflächenenergetiken und Oberflächentexturierung.
Selective Rhodium‐Catalyzed Reduction of Tertiary Amides in Amino Acid Esters and Peptides
Authors: Das Shoubhik , Li Yuehui , Bornschein Christoph , Pisiewicz Sabine , Kiersch Konstanze , Michalik Dirk , Gallou Fabrice , Junge Kathrin , Beller Matthias
Published: July 2015

Efficient reduction of the tertiary amide bond in amino acid derivatives and peptides is described. Functional group selectivity has been achieved by applying a commercially available rhodium precursor and bis(diphenylphosphino)propane (dppp) ligand together with phenyl silane as a reductant. This methodology allows for specific reductive derivatization of biologically interesting peptides and offers straightforward access to a variety of novel peptide derivatives for chemical biology studies and potential pharmaceutical applications. The catalytic system tolerates a variety of functional groups including secondary amides, ester, nitrile, thiomethyl, and hydroxy groups. This convenient hydrosilylation reaction proceeds at ambient conditions and is operationally safe because no air‐sensitive reagents or highly reactive metal hydrides are needed.
Single‐Molecule Visualization of the Activity of a Zn2+‐Dependent DNAzyme
Authors: Endo Masayuki , Takeuchi Yosuke , Suzuki Yuki , Emura Tomoko , Hidaka Kumi , Wang Fuan , Willner Itamar , Sugiyama Hiroshi
Published: July 2015

We demonstrate the single‐molecule imaging of the catalytic reaction of a Zn2+‐dependent DNAzyme in a DNA origami nanostructure. The single‐molecule catalytic activity of the DNAzyme was examined in the designed nanostructure, a DNA frame. The DNAzyme and a substrate strand attached to two supported dsDNA molecules were assembled in the DNA frame in two different configurations. The reaction was monitored by observing the configurational changes of the incorporated DNA strands in the DNA frame. This configurational changes were clearly observed in accordance with the progress of the reaction. The separation processes of the dsDNA molecules, as induced by the cleavage by the DNAzyme, were directly visualized by high‐speed atomic force microscopy (AFM). This nanostructure‐based AFM imaging technique is suitable for the monitoring of various chemical and biochemical catalytic reactions at the single‐molecule level.
Stereoselective Synthesis of α‐3‐Deoxy‐D‐manno‐oct‐2‐ulosonic Acid (α‐Kdo) Glycosides Using 5,7‐O‐Di‐tert‐butylsilylene‐Protected Kdo Ethyl Thioglycoside Donors
Authors: Huang Jia‐Sheng , Huang Wei , Meng Xue , Wang Xin , Gao Peng‐Cheng , Yang Jin‐Song
Published: July 2015

An efficient methodology for the synthesis of α‐Kdo glycosidic bonds has been developed with 5,7‐O‐di‐tert‐butylsilylene (DTBS) protected Kdo ethyl thioglycosides as glycosyl donors. The approach permits a wide scope of acceptors to be used, thus affording biologically significant Kdo glycosides in good to excellent chemical yields with complete α‐selectivity. The synthetic utility of an orthogonally protected Kdo donor has been demonstrated by concise preparation of two α‐Kdo‐containing oligosaccharides.
Nickel‐katalysierte Cyclopropanierung mit NMe4OTf und nBuLi
Authors: Künzi Stefan A. , Sarria Toro Juan Manuel , den Hartog Tim , Chen Peter
Published: July 2015

Nickel wurde als Katalysator für die Cyclopropanierung von unaktivierten Olefinen durch in situ hergestelltes Lithiomethyltrimethylammoniumtriflat als Methylendonor identifiziert. Eine mechanistische Hypothese wird vorgeschlagen, welche die Entstehung eines reaktiven Nickelcarben beinhaltet, um einige interessante Beobachtungen zu erklären. Zudem beleuchten unsere Resultate einen Bericht von Franzen und Wittig aus dem Jahre 1960, der später wegen Irreproduzierbarkeit zurückgezogen wurde, und liefern eine rationale Basis für eine systematische Entwicklung der Reaktion für präparative Zwecke als Alternative zu Diazomethan oder Simmons‐Smith‐Bedingungen.
Regio‐ and Enantioselective Aza‐Diels–Alder Reactions of 3‐Vinylindoles: A Concise Synthesis of the Antimalarial Spiroindolone NITD609
Authors: Zheng Haifeng , Liu Xiaohua , Xu Chaoran , Xia Yong , Lin Lili , Feng Xiaoming
Published: July 2015

An asymmetric aza‐Diels–Alder reaction of 3‐vinylindoles with isatin‐derived ketimines has been developed. A series of spiroindolone derivatives were thus obtained in good to excellent yields with excellent enantioselectivity (up to 96 % yield and 99 % ee). Furthermore, the antimalarial compound NITD609 could be obtained in three steps with an overall yield of 40.6 %. Control experiments and operando IR experiments imply a concerted reaction pathway. The regioselectivity and exo selectivity result from π–π interactions between the two indoline rings of the two reactants.
Biomimetic Self‐Healing
Authors: Diesendruck Charles E. , Sottos Nancy R. , Moore Jeffrey S. , White Scott R.
Published: July 2015

Self‐healing is a natural process common to all living organisms which provides increased longevity and the ability to adapt to changes in the environment. Inspired by this fitness‐enhancing functionality, which was tuned by billions of years of evolution, scientists and engineers have been incorporating self‐healing capabilities into synthetic materials. By mimicking mechanically triggered chemistry as well as the storage and delivery of liquid reagents, new materials have been developed with extended longevity that are capable of restoring mechanical integrity and additional functions after being damaged. This Review describes the fundamental steps in this new field of science, which combines chemistry, physics, materials science, and mechanical engineering.
Transparent Electrodes Printed with Nanocrystal Inks for Flexible Smart Devices
Authors: Song Jizhong , Zeng Haibo
Published: July 2015

Transparent electrodes (TEs) are crucial in a wide range of modern electronic and optoelectronic devices. However, traditional TEs cannot meet the requirements of smart devices under development in unique fields, such as electronic skins, wearable electronics, robotic skins, flexible and stretchable displays, and solar cells. Emerging TEs printed with nanocrystal (NC) inks are inexpensive and compatible with solution processes, and have huge potential in flexible, stretchable, and wearable devices. Every development in ink‐based electrodes makes them more competitive for practical applications in various smart devices. Herein, we provide an overview of emergent ink‐based electrodes, such as transparent conducting oxides, metal nanowires, graphene, and carbon nanotubes, and their application in solution‐based flexible and stretchable devices.
Vibrational Imaging of Glucose Uptake Activity in Live Cells and Tissues by Stimulated Raman Scattering
Authors: Hu Fanghao , Chen Zhixing , Zhang Luyuan , Shen Yihui , Wei Lu , Min Wei
Published: July 2015

Glucose is a ubiquitous energy source for most living organisms. Its uptake activity closely reflects cellular metabolic demand in various physiopathological conditions. Extensive efforts have been made to specifically image glucose uptake, such as with positron emission tomography, magnetic resonance imaging, and fluorescence microscopy, but all have limitations. A new platform to visualize glucose uptake activity in live cells and tissues is presented that involves performing stimulated Raman scattering on a novel glucose analogue labeled with a small alkyne moiety. Cancer cells with differing metabolic activities can be distinguished. Heterogeneous uptake patterns are observed with clear cell–cell variations in tumor xenograft tissues, neuronal culture, and mouse brain tissues. By offering the distinct advantage of optical resolution but without the undesirable influence of fluorophores, this method will facilitate the study of energy demands of living systems with subcellular resolution.
Organocatalytic Glycosylation by Using Electron‐Deficient Pyridinium Salts
Authors: Das Somnath , Pekel Daniel , Neudörfl Jörg‐M. , Berkessel Albrecht
Published: July 2015

A new organocatalytic glycosylation method based on electron‐deficient pyridinium salts is reported. At ambient temperature and catalyst loadings as low as 1 mol %, 2‐deoxyglycosides were formed from benzyl‐ and silyl‐protected glycals and primary or secondary glycosyl acceptors, with excellent yields and anomeric selectivity. Mechanistic investigations point to alcohol–pyridinium conjugates (1,2‐addition products) as key intermediates in the catalytic cycle.
A 6,11,16‐Triarylbiphenylcorrole with an adj‐CCNN Core: Stabilization of an Organocopper(III) Complex
Authors: Adinarayana B. , Thomas Ajesh P. , Suresh Cherumuttathu H. , Srinivasan A.
Published: July 2015

An adj‐dicarbacorrole with CCNN in the core is achieved by replacing the bipyrrole moiety by a simple polycyclic aromatic hydrocarbon, such as biphenyl unit. Spectroscopic studies and structural analyzes confirm the absence of macrocyclic aromatization, thus leading to overall nonaromatic character. The trianionic core is effectively utilized to stabilize a copper(III) ion to form an organocopper complex.
[Fe19] “Super‐Lindqvist” Aggregate and Large 3D Interpenetrating Coordination Polymer from Solvothermal Reactions of [Fe2(OtBu)6] with Ethanol
Authors: Nachtigall Olaf , Kusserow Matthias , Clérac Rodolphe , Wernsdorfer Wolfgang , Menzel Michael , Renz Franz , Mrozinski Jerzy , Spandl Johann
Published: July 2015

The syntheses, crystal structures, and physical properties of [HFe19O14(OEt)30] and {Fe11(OEt)24}∞ are reported. [HFe19O14(OEt)30] has an octahedral shape. Its core with a central Fe metal ion surrounded by six μ6‐oxo ligands is arranged in the rock salt structure. {Fe11(OEt)24}∞ is a mixed‐valence coordination polymer in which FeIII metal ions form three 3D interpenetrating (10,3)‐b nets. The arrangement of the FeIII ions can also be compared to that of Si ions in α‐ThSi2. Thus, the described structures are at the interface between molecular and solid‐state chemistry.
A Priori Estimation of Organic Reaction Yields
Authors: Emami Fateme S. , Vahid Amir , Wylie Elizabeth K. , Szymkuć Sara , Dittwald Piotr , Molga Karol , Grzybowski Bartosz A.
Published: July 2015

A thermodynamically guided calculation of free energies of substrate and product molecules allows for the estimation of the yields of organic reactions. The non‐ideality of the system and the solvent effects are taken into account through the activity coefficients calculated at the molecular level by perturbed‐chain statistical associating fluid theory (PC‐SAFT). The model is iteratively trained using a diverse set of reactions with yields that have been reported previously. This trained model can then estimate a priori the yields of reactions not included in the training set with an accuracy of ca. ±15 %. This ability has the potential to translate into significant economic savings through the selection and then execution of only those reactions that can proceed in good yields.
Dialkyl Ether Formation by Nickel‐Catalyzed Cross‐Coupling of Acetals and Aryl Iodides
Authors: Arendt Kevin M. , Doyle Abigail G.
Published: July 2015

A new substrate class for nickel‐catalyzed C(sp3) cross‐coupling reactions is reported. α‐Oxy radicals generated from benzylic acetals, TMSCl, and a mild reductant can participate in chemoselective cross‐coupling with aryl iodides using a 2,6‐bis(N‐pyrazolyl)pyridine (bpp)/Ni catalyst. The mild, base‐free conditions are tolerant of a variety of functional groups on both partners, thus representing an attractive CC bond‐forming approach to dialkyl ether synthesis. Characterization of a [(bpp)NiCl] complex relevant to the proposed catalytic cycle is also described.
Catalytic Silylations of Alcohols: Turning Simple Protecting‐Group Strategies into Powerful Enantioselective Synthetic Methods
Authors: Xu Li‐Wen , Chen Yun , Lu Yixin
Published: July 2015

In recent years, remarkable progress has been made in the enantioselective silylation of alcohols. Owing to the successful site‐ and stereoselective functionalization of hydroxy groups, silyl ether formations have evolved from being a simple reaction for functional‐group protection into a powerful enantioselective process. In this Minireview, we highlight important recent findings in this emerging field.
Chemical Detoxification of Organomercurials
Authors: Banerjee Mainak , Karri Ramesh , Rawat Kuber Singh , Muthuvel Karthick , Pathak Biswarup , Roy Gouriprasanna
Published: July 2015

Organomercurials including methylmercury are ubiquitous environmental pollutants and highly toxic to humans. Now it could be shown that N‐methylimidazole based thiones/selones having an N‐CH2CH2OH substituent are remarkably effective in detoxifying various organomercurials to produce less toxic HgE (E=S, Se) nanoparticles. Compounds lacking the N‐CH2CH2OH substituent failed to produce HgE nanoparticles upon treatment with organomercurials, suggesting that this moiety plays a crucial role in the detoxification by facilitating the desulfurization and deselenization processes. This novel way of detoxifying organomercurials may lead to the discovery of new compounds to treat patients suffering from methylmercury poisoning.
Finding the Most Catalytically Active Platinum Clusters With Low Atomicity
Authors: Imaoka Takane , Kitazawa Hirokazu , Chun Wang‐Jae , Yamamoto Kimihisa
Published: July 2015

On a subnanometer scale, an only one‐atom difference in a metal cluster may cause significant transitions in the catalytic activity due to the electronic and geometric configurations. We now report the atomicity‐specific catalytic activity of platinum clusters with significantly small atomicity, especially below 20. The atomic coordination structure is completely different from that of the larger face‐centered cubic (fcc) nanocrystals. Here, an electrochemical study on such small clusters, in which the atomicity ranged between 12 and 20, revealed Pt19 as the most catalytically active species. In combination with a theoretical study, a common structure that leads to a high catalytic performance is proposed.
Encapsulating Inorganic Acetylene, HBNH, Using Flanking Coordinative Interactions
Authors: Swarnakar Anindya K. , Hering‐Junghans Christian , Nagata Koichi , Ferguson Michael J. , McDonald Robert , Tokitoh Norihiro , Rivard Eric
Published: July 2015

A stable donor–acceptor coordination complex of the elusive parent inorganic iminoborane HBNH (a structural analogue of acetylene) is reported. This species was generated via thermally induced N2 elimination/1,2‐H migration from a hydrido(azido)borane adduct NHC⋅BH2N3 (NHC=N‐heterocyclic carbene) in the presence of a fluorinated triarylborane. The mechanism of this process was also investigated by computational and isotopic labeling studies. This transformation represents a new and potentially modular route to unsaturated inorganic building blocks for advanced material synthesis.
A Graphitic‐C3N4 “Seaweed” Architecture for Enhanced Hydrogen Evolution
Authors: Han Qing , Wang Bing , Zhao Yang , Hu Chuangang , Qu Liangti
Published: July 2015

A seaweed‐like graphitic‐C3N4 (g‐C3N4 “seaweed”) architecture has been prepared by direct calcination of the freeze‐drying‐assembled, hydrothermally treated dicyandiamide fiber network. The seaweed network of mesoporous g‐C3N4 nanofibers is favorable for light harvesting, charge separation and utilization of active sites, and has highly efficient photocatalytic behavior for water splitting. It exhibits a high hydrogen‐evolution rate of 9900 μmol h−1 g−1 (thirty times higher than that of its g‐C3N4 bulk counterpart), and a remarkable apparent quantum efficiency of 7.8 % at 420 nm, better than most of the g‐C3N4 nanostructures reported. This work presents a very simple method for designing and developing high‐performance catalysts for hydrogen evolution.
Dissolution Engineering of Platinum Alloy Counter Electrodes in Dye‐Sensitized Solar Cells
Authors: Tang Qunwei , Zhang Huihui , Meng Yuanyuan , He Benlin , Yu Liangmin
Published: July 2015

The dissolution of platinum (Pt) has been one of the heart issues in developing advanced dye‐sensitized solar cells (DSSCs). We present here the experimental realization of stable counter‐electrode (CE) electrocatalysts by alloying Pt with transition metals for enhanced dissolution resistance to state‐of‐the‐art iodide/triiodide (I−/I3−) redox electrolyte. Our focus is placed on the systematic studies of dissolution engineering for PtM0.05 (M=Ni, Co, Fe, Pd, Mo, Cu, Cr, and Au) alloy CE electrocatalysts along with mechanism analysis from thermodynamical aspects, yielding more negative Gibbs free energies for the dissolution reactions of transition metals. The competitive reactions between transition metals with iodide species (I3−, I2) could protect the Pt atoms from being dissolved by redox electrolyte and therefore remain the high catalytic activity of the Pt electrode.
Poplar wood–methylol urea composites prepared by in situ polymerization. II. Characterization of the mechanism of wood modification by methylol urea
Authors: Lang Qian , Bi Zeng , Pu Jun‐Wen
Published: July 2015

A prepolymer was used to prepare wood/prepolymer composites by a pulse‐dipping machine. The mechanical properties and dimensional stability were evaluated. The characterization of natural and modified woods was performed by Fourier transform infrared spectroscopy, 13C‐NMR spectroscopy, X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) with energy‐dispersive X‐ray analysis (EDXA). Cross‐polarization/magic‐angle spinning 13C‐NMR analysis revealed that the in situ polymerization between the prepolymer and the hydroxyls in the wood structure took place with the reduction of hydroxyl groups. XPS analysis indicated that the content of carbon decreased, whereas the content of oxygen increased. SEM–EDXA indicated a good dispersion of the modifier in the wood fiber and other vertical cells. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42406.
Preparation, characterization, and antibacterial activities of quaternarizedN‐halamine‐grafted cellulose fibers
Authors: Chen Xiaoqin , Liu Zuliang , Cao Weiwei , Yong Chunyan , Xing Xiaodong
Published: July 2015

A viable method for coating of cellulose fiber with quaternarized N‐halamine is reported in this article. The use of quaternary ammonium salt group in combination with N‐halamine group can reinforce the antibacterial activity. The chemical structure of as‐synthesized N‐halamine precursor 4‐(Bromo‐acetic acid methylester)‐4‐ethyl‐2‐ oxazolidinone (BEO) was characterized by1H‐NMR. The cellulose fibers were characterized by Fourier transform infrared spectra and X‐ray photoelectron spectra. The spectra data confirmed that the quaternarized N‐halamine‐grafted cellulose fibers were successfully obtained. The antibacterial properties of functional fibers were challenged with both Gram positive and Gram negative bacteria. The antibacterial tests and showed that the as‐prepared antibacterial cellulose fibers exhibited powerful and rapid bactericidal performance against both Gram negativeE. coliand Gram positiveS. aureus. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 42702.
Cadaveric anatomy in the future of medical education: What is the surgeons view?
Authors: Sheikh Ahmad Hassan , Barry Denis S. , Gutierrez Humberto , Cryan John F. , O'Keeffe Gerard W.
Published: July 2015

Reduced contact hours and access to cadaveric/prosection‐based teaching in medical education has led to many doctors reporting inadequate anatomical knowledge of junior doctors. This trend poses significant risk, but perhaps most of all in surgery. Here the opinions of surgeons regarding current and future teaching practices in anatomy were surveyed. Eighty surgeons were invited to complete a questionnaire, 48 of which were returned for a 60% response rate. Respondents were asked to select the method they viewed as the best method of teaching anatomy. Sixty‐five percent of respondents selected “cadaver/prosection demonstration” (P < 0.001), while 55% of respondents, thought it should be enhanced in anatomy education (P < 0.001). Finally, respondents were asked to select what form of imaging should be further explored in anatomical education. Seventy‐five percent of respondents’ selected computerized tomography (CT) imaging compared to other imaging modalities (P < 0.001). These data show that surgeons view cadaveric/prosection‐based teaching as the most beneficial method of teaching anatomy and that it should be enhanced in medical education. Furthermore, surgeons suggested that CT should be further integrated into anatomical education. These findings support the continued use of cadaveric/prosection‐based teaching, and will help inform the integration of radiology in the design and implementation of anatomy teaching in medical education. Anat Sci Educ 9: 203–208. © 2015 American Association of Anatomists.
Synthesis of thiazolium salts and their screening for catalytic activity
Authors: Lee Seul Ki , Kim Do Joong , Park Jin Kyoon
Published: July 2015

A facile synthetic method to prepare thiazolium‐based ionic liquids in high yield was developed. The direct alkylation of thiazole was performed using a trialkyl orthoester as both the alkyl donor and the solvent. The synthesized thiazolium salts were subsequently screened for their ability to catalyze the benzoin condensation reaction. Of the salts that were tested, 3‐butyl,4,5‐dimethyl thiazolium salt, was found to be the best catalyst.
Glucocorticoid Enhances Viability of Human Respiratory Epithelial Cells Inflicted by Ambient Particulate Matter
Authors: Heo Nam , Baek Ahruem , Baek Yu Mi , Byeon Sunjoo , Choi Kum Chan , Kim Joo Yeon , Kwon Jae Hwan , Kim Dong‐Eun
Published: July 2015

Particulate matter (PM) is one of the most common ambient air pollutants, which is derived from diesel engines, wildfires, yellow dust, and other combustion sources. Especially, PM with an aerodynamic diameter of <2.5 µm (PM2.5
) enhances risks of damaging respiratory organs. Previous studies have reported that PM‐induced autophagy and apoptosis can be considered as a phenomenal molecular mechanism of PM‐mediated cytotoxicity in lung cancer epithelial cells. In this study, we investigate the effects of PM2.5
on cellular responses in human nasal epithelial primary cells and lung cancer cells. The respiratory epithelial cells showed both time‐ and concentration‐dependent decrease of cell viability when the cells were exposed to PM, which can be attributed to increased levels of reactive oxygen species (ROS) in the cells. In addition to inducing autophagy via increase of microtubule‐associated protein light chain‐3 (LC3) puncta, PM exposure also induced the expression of inflammatory cytokines such as IL‐6 and 8 in human respiratory epithelial cells. Thus, inflammation response, as well as autophagosome formation due to increased ROS, is responsible for apoptotic death of respiratory epithelial cells under challenge of PM. The glucocorticoid ciclesonide used to treat asthma and allergic rhinitis was shown to be effective in reducing cellular mortality, probably by reducing inflammatory cytokines. These results suggest that PM2.5
‐induced inflammation plays a key role in apoptotic cell death in respiratory epithelial cells, which may be treated by an anti‐inflammatory glucocorticoid.
Application of NMR Spectroscopy to Assessment of Radiation Dose and Time Lapse
Authors: Kang Chang‐Mo , Hyeon Jin Seong , Kim So Ra , Lee Eun Kyeong , Yun Hyun Jin , Kim Sun Young , Chae Young Kee
Published: July 2015

We employed a rat model system as a first step toward studying the influence of ionizing radiation on the parameters of the metabolite markers in the liver of rats exposed to X‐ray at the dose of 6 Gy. We applied whole‐body X‐ray irradiation to the rat, and profiled metabolites by 2D nuclear magnetic resonance (NMR) spectroscopy to sort out candidate molecules that can be used to deduce the information needed. We identified 32 metabolites from rat liver extracts. Statistical analysis suggested that samples with or without X‐ray irradiation and samples harvested 24 or 72 h after irradiation could approximately be divided into four quadrants of the principal component space. Combinatorial use of signals from characteristic metabolites could differentiate X‐ray‐irradiated samples from controls and, furthermore, samples collected 24 h after irradiation from those after 72 h. We hope that this work would form a base for treating radiation‐poisoned patients in the future.
Chiral Profiling Analysis of β‐Blockers by Capillary Electrophoresis Using Dual Chiral Selectors
Authors: Paik Man‐Jeong , Kim Kyoung‐Rae , Lee Wonjae
Published: July 2015

Simultaneous analysis of several β‐blockers using a novel dual chiral selector system was achieved for their accurate chiral discrimination by chiral capillary electrophoresis (CE) in normal polarity mode. The CE system was operated using heptakis(2,6‐di‐O‐methyl)‐β‐cyclodextrin (DM‐β‐CD) dissolved in 100 mM phosphoric acid–triethanolamine buffer (pH 3) and (+)‐ or (−)‐18‐crown‐6‐tetracarboxylic acid (18‐C‐6‐TA) as a co‐chiral selector in DM‐β‐CD solution. All eight investigated analytes were resolved using (+)‐18‐C‐6‐TA as a co‐chiral selector in the presence of DM‐β‐CD solution, whereas the other β‐blockers, except propranolol, were resolved using (−)‐18‐C‐6‐TA as the second chiral selector in DM‐β‐CD solution. Also, DM‐β‐CD had a major effect on chiral discrimination compared with 18‐C‐6‐TA as a co‐chiral selector. Relative migration times to that of (S)‐pindolol as an internal standard were characteristic of each enantiomer with good precision. The method showed good linearity with a correlation coefficient (r ≥ 0.993). The precision as a percentage of relative standard deviation (% RSD) and accuracy as a percentage of relative error (% RE) ranged from 0.5 to 9.6 and from −5.7 to 9.1, respectively. These were adequate for the chiral assay of the β‐blockers investigated. Thus, the present chiral profiling method is expected to be useful for accurate chiral discrimination and optical purity tests of chiral β‐blockers and their related drugs.
Nucleophilic Substitution Reactions of 2,4‐Dinitrophenyl X‐Substituted‐Benzenesulfonates and Y‐Substituted‐Phenyl 4‐Nitrobenzenesulfonates with Azide Ion: Regioselectivity and Reaction Mechanism
Authors: Moon Ji‐Hyun , Kim Min‐Young , Han So‐Yeop , Um Ik‐Hwan
Published: July 2015

The second‐order rate constants for reactions of 2,4‐dinitrophenyl X‐substituted‐benzenesulfonates (4a–4f) and Y‐substituted‐phenyl‐4‐nitrobenzenesulfonates (5a–5f) with ion have been measured spectrophotometrically. The reactions of 4a–4f proceed through SO and CO bond fission pathways competitively. Fraction of the SO bond fission decreases rapidly as the substituent X in the benzenesulfonyl moiety changes from an electron‐withdrawing group to an electron‐donating group. The Hammett plots for reactions of 4a–4f are linear with ρX = 1.87 and 0.56 for the SO and CO bond fission, respectively. The fact that the substituent X is further away from the reaction site of the CO bond fission than that of the SO bond fission is one reason for the smaller ρX value. The nature of the reaction mechanism (i.e., a stepwise mechanism in which expulsion of the leaving group occurs after the rate‐determining step) is also responsible for the smaller ρX value obtained from the CO bond fission. The Brønsted‐type plot for the reactions of 5a–5f is linear with βlg = −0.63, which is typical for reactions reported previously to proceed through a concerted mechanism. Effects of substituents X and Y on regioselectivity and reaction mechanism are discussed in detail.
Comparison of MALDI and ESI for Relative Quantification of Citrullination via Skewed Isotopic Distribution Patterns
Authors: Shin Eunbi , Cha Sangwon
Published: July 2015

Arginine residues in a protein can be enzymatically deiminated to citrulline residues, and this post‐translational modification of proteins, called citrullination, has been known to be associated with autoimmune diseases such as rheumatoid arthritis. Since citrullination of an arginine residue causes a mass shift of only 1 Da, isotopic distribution patterns of citrullinated and its control (non‐citrullinated) peptides overlap each other, and the resulting isotopic pattern is skewed with respect to that of the control peptide. Recently, Deforce and coworkers utilized the citrullination‐induced skewed isotopic patterns for estimating the extent of citrullination (J. Proteome Res. 2012, 11, 5245). However, electrospray ionization (ESI), which Deforce and coworkers employed, is not fully suitable for this type of quantification because the number of potential charge sites on a citrullinated peptide is less than that on its control peptide and this leads to different ion abundances for a given charge state. In this study, we employed matrix‐assisted laser desorption/ionization (MALDI) instead of ESI for quantification of citrullination because the preference for singly charged ion formation by MALDI may overcome the aforementioned issue. Our results show that the isotopic patterns generated by MALDI time‐of‐flight (TOF) mass spectrometry (MS) reflect the citrullination contents better than those generated by ESI linear ion trap (LIT) MS.
The Effect of Preparation Parameters in Thermal Decomposition of Ruthenium Dioxide Electrodes on Chlorine Electro‐Catalytic Activity
Authors: Luu Tran Le , Kim Choonsoo , Kim Jiye , Kim Seonghwan , Yoon Jeyong
Published: July 2015

When fabricating a RuO2
electrode, the high electro‐catalytic activity in chlorine evolution is considered as one of the most important factors. Thermal decomposition method carried out under various fabrication conditions including the types of solvents, precursors, and calcination times have led to the enhancement electro‐catalytic activity of RuO2
electrode in chlorine evolution. Nevertheless, it has not been fully investigated how these parameters directly affect to the chlorine evolution efficiency in the RuO2
electrode. Therefore, the aim of this study was to investigate the effect on the chlorine evolution in RuO2
electrodes, depending upon the preparation parameters including solvents, precursors, and calcination times. As major results, the chlorine evolution efficiency was dominantly affected by these three major preparation parameters. The RuO2
electrode fabricated with ethanol as the solvent showed highest chlorine evolution efficiency. The choice of Ru(AcAc)3 as precursor and the increase of the calcination time up to 3 h are also the good choices for increasing chlorine electrocatalytic activities. The chlorine evolution efficiency was not significantly related to the total voltammetric charge but to the outer voltammetric charge, which is affected by the morphology of the RuO2
electrode surface. The size and number of cracks on the electrode surfaces or the outer voltammetric charges increased with easily evaporated solvents, decomposed precursors, and tensile stress from longer thermal treatments.
Graft Polymerization of Polyacrylonitrile or Poly(methyl methacrylate) onto Polyurethane for the Improvement of Mechanical Properties and Water Vapor Permeability
Authors: Chung Yong‐Chan , Kim Ha Youn , Choi Jae Won , Chun Byoung Chul
Published: July 2015

Polyacrylonitrile (PAN) or poly(methyl methacrylate) (PMMA) was graft‐polymerized onto polyurethane (PU) to form the urethane‐acrylate polymers grafted with PAN (UA series) or PMMA (UM series). With an increase in the acryl content, the T
m, ΔH
m
, and T
g did not significantly change for the UA and UM series. The tensile strengths of the UA and UM series increased with the acryl content, whereas those of the control PUs did not. The breaking strain of the UA and UM series, and control PUs remained the same with the increase in the acryl content. The shape recovery and shape retention of the UA and UM series remained high after four repeated tests. The UA and UM series demonstrated better low‐temperature flexibility and water permeability than the unmodified PU.
Optimization of Enzyme Activity Assay for Screening of Acryl CoA: Monoacylglycerol Acyltransferase 2 Inhibitors
Authors: Park Ji Seon , Park Sung Bum , Jeon Hyo‐Jin , Jung Won Hoon , Kim Hee Youn , Kang Seung Kyu , Ahn Jin Hee , Rhee Sang Dal , Kim Kwang Rok , Kim Ki Young
Published: July 2015

Acryl CoA: monoacylglycerol acyltransferase 2, (MGAT2) is interesting target and useful strategy for treating metabolic‐related diseases such as obesity, type 2 diabetes, hypertriglyceridemia and non‐alcoholic fatty liver disease. In this study, we are optimized a new and easy‐to‐use screening assay system to identify novel MGAT2 inhibitors. We optimized high‐quality Perkinelmer's FlashPlates based MGAT2 assay have a short time‐consuming, adjust for high throughput screening (HTS) and can perform extensive screening. This screening technology platform is considered to be particularly useful for biological targets for which the conventional HTS assays are difficult to implement.
Antimony‐based Intermetallic Alloy Anodes for High‐Performance Sodium‐Ion Batteries: Effect of Additives
Authors: Hur Jaehyun , Kim Il Tae
Published: July 2015

Antimony (Sb)‐containing intermetallic alloy compound consisting of molybdenum (Mo) and Sb dispersed in an amorphous carbon matrix was developed via high‐energy mechanical milling and utilized as an anode for a sodium‐ion battery. The structure and morphology of the as‐prepared material were characterized using X‐ray diffraction (XRD) and transmission electron microscope. Ex situ XRD measurement confirmed the formation of a Na3Sb phase during sodiation. The electrochemical performance of the as‐prepared Mo3Sb7
C composite demonstrated stable cyclability up to 40 cycles at a current rate of 100 mA/g. When a fluoroethylene carbonate additive was introduced into the electrolyte, the Mo3Sb7
C anodes exhibited a longer cyclic life with a capacity retention of ~90% at 100 cycles, as well as superior rate‐cyclic performance corresponding to a capacity retention of more than 70% at 10 000 mA/g. This enhanced electrochemical performance could be ascribed to the formation of a stable solid electrolyte interphase layer, smaller charge‐transfer resistance, and better dispersion of Mo3Sb7
nanoparticles in the carbon matrix.
Surface‐enhanced Raman Spectroscopic Studies of Ellagic Acid in Silver Colloids
Authors: Lee Seung‐Jang , Cheong Byeong‐Seo , Cho Han‐Gook
Published: July 2015

Surface‐enhanced Raman scattering (SERS) spectroscopy has been applied for the vibrational characterization of ellagic acid (EA), a natural organic dye, using citrate‐reduced silver colloids. The infrared and FT‐Raman spectra of EA in the solid state were examined for comparison. Spectral assignments of the observed bands were aided by density functional theory (DFT) calculations employing the B3LYP functional. The variations in the SERS spectrum with pH and excitation wavelength were analyzed to gain information on the adsorption‐ and pH‐dependent behaviors of the natural dye on the metal surface. On the basis of the observed spectral features and DFT calculations, the adsorption configuration of EA on the silver metal surface is proposed.
Pulling Speed Dependence of Single Molecular Plateau Length
Authors: Kim Deok Hyun , Kim Taekyeong
Published: July 2015

We compared the single molecular plateau length by varying the piezo pulling speed for the Ag electrodes using a scanning tunneling microscope‐based break junction technique. We found that the molecular plateau length was longer for a high pulling speed than that for a low pulling speed. Furthermore, we observed that the gap distance between the top and bottom Ag electrodes after the metal point contact was ruptured varied with a piezo pulling speed, which is attributed to the atomic diffusion of Ag in pulling a piezo. We also found that the molecular plateau length has no pulling speed dependence for Au electrodes. Our results open a new path to characterize the electrical or mechanical properties of the organic devices based on a single molecule.
Synthesis and Anti‐inflammatory Activity of Phenylbutenoid Dimer Analogs
Authors: Kim Sung‐Soo , Fang Yuanying , Park Haeil
Published: July 2015

Several phenylbutenoid dimer (PBD) analogs were synthesized and evaluated for their inhibitory activities against nitric oxide (NO) production and TNF‐α release. The PBD analogs were synthesized via Diels–Alder and subsequent Schlosser reactions as key steps. Among the tested compounds, two analogs (8c, 8f) exhibited much stronger inhibitory activity against LPS‐stimulated NO production and TNF‐α release in RAW 264.7 cells than that of wogonin.
Tsuji–Wacker Oxidation of Terminal Olefins using a Palladium–Carbon Nanotube Nanohybrid
Authors: Donck Simon , Gravel Edmond , Shah Nimesh , Jawale Dhanaji V. , Doris Eric , Namboothiri Irishi N. N.
Published: July 2015

Palladium nanoparticles supported on carbon nanotubes were used in the Tsuji–Wacker oxidation. The palladium‐based nanohybrid was found to be very active in combination with cuprous chloride for the selective oxidation of terminal olefins into methyl ketones. The co‐catalytic system operates under very mild and sustainable conditions (room temperature, atmospheric pressure, low catalyst loading), as opposed to previously reported catalysts, and can be recycled without any loss in activity.
One‐Pot Synthesis of a Nitrogen‐Doped Carbon Composite by Electrospinning as a Metal‐Free Catalyst for Oxidation of H2S to Sulfur
Authors: Liu Yuefeng , Duong‐Viet Cuong , Luo Jingjie , Hébraud Anne , Schlatter Guy , Ersen Ovidiu , Nhut Jean‐Mario , Pham‐Huu Cuong
Published: July 2015

A macroscopic composite consisting of nitrogen‐doped carbon fibers (N@CFs) was synthesized by electrospinning. The as‐prepared N@CF material was further applied as a metal‐free catalyst in the catalytic oxidation of H2S to sulfur, which is one of the most important purification processes for raw chemical resources (that is, biogas, natural gas, and petrochemical compounds). The catalyst, after a carbonization step at T=800 °C, exhibits a high and stable desulfurization activity for more than 100 h of testing with 57 % H2S conversion and 95 % sulfur selectivity at T=230 °C, which is two times higher than that of the most active metal‐based catalyst (Fe2O3/SiC). The desulfurization performance could also be improved by changing the reactant velocity. Moreover, the macroscopic shaping with an inner hierarchical structure network allows the avoidance of problems linked with the transport and handling of nanoscopic carbon‐based materials and also enhances the mass diffusion during the oxidation reaction.
Engineering Nanoporous Iron(III) Oxide into an Effective Water Oxidation Electrode
Authors: Haschke Sandra , Wu Yanlin , Bashouti Muhammad , Christiansen Silke , Bachmann Julien
Published: July 2015

The geometric effects of nanostructuring a pure Fe2O3 surface on its electrochemical water oxidation performance at neutral pH were systematically explored. Atomic layer deposition was used to coat the inner walls of cylindrical “anodic” nanopores ordered in parallel arrays with a homogeneous Fe2O3 layer. Annealing and electrochemical treatments generated a roughened surface, as demonstrated by X‐ray photoelectron spectroscopy and electrochemical impedance spectroscopy, the larger geometric area of which increases current densities. Combining these treatments with the “anodic” pore geometry delivered an effective increase in turnover by almost three orders of magnitude with respect to a smooth, planar Fe2O3 surface. However, the current density depended on the pore length in a non‐monotonic manner. An optimal length was found that maximized turnover by equating the rate of transport in the electrolyte with that of charge transfer across the interface.
Silica‐Grafted SnIV Catalysts in Hydrogen‐Transfer Reactions
Authors: Conrad Sabrina , Verel René , Hammond Ceri , Wolf Patrick , Göltl Florian , Hermans Ive
Published: July 2015

SnIV‐substituted zeolites show remarkable activity for important Lewis acid catalyzed reactions. In such complex catalytic systems it is, however, difficult to untangle the influence of all parameters contributing to the overall performance, and hence to rationally improve the catalyst. In this work, we studied silica‐grafted SnIV sites to reduce this complexity by eliminating the potential influence of pore confinement. The surface‐anchored SnIV sites were modified by calcination and silylation to increase Lewis acidity and hydrophobicity. Various techniques were used to characterize the materials, including the adsorption of cyclohexanone by using FTIR spectroscopy. We relate our spectroscopic results with catalytic tests and compare our model catalysts with benchmark Snβ zeolite. This suggested that besides active‐site structure, also hydrophobicity and confinement effects influence the activity. Our work demonstrates the utility of model systems to separate the different contributions to catalytic activity.
Hierarchically Porous and Nitrogen‐Doped Graphene‐Like Microspheres as Stable Anodes for Lithium‐Ion Batteries
Authors: Sun Dongfei , Yan Xingbin , Yang Juan , Zhang Peng , Xue Qunji
Published: July 2015

Novel 3D hierarchically porous and nitrogen‐doped graphene‐like microspheres (3D NPGSs) are prepared by precursor‐assisted chemical vapor deposition. 3D NPGSs obtained by using Ni microspheres as a structural template exhibit a 3D conductive framework, and have a well‐defined porous structure, large surface area and appropriate heteroatom doping, making them suitable for high‐performance storage of lithium ions. Consequently, a good rate capability and excellent cycle performance are achieved using the 3D NPGSs as anodes for lithium storage, and a high reversible capacity of 840 mA h g−1 is obtained after 200 cycles. For a further capacitance boost, a thin layer of iron oxide nanoparticles is deposited onto the 3D NPGSs. The resulting 3D FeOx–NPGS electrode exhibits a stable reversible capacity up to 1343 mA h g−1 after 100 cycles.
Synthesis of Integrated Layered‐Spinel Composite Cathode Materials for High‐Voltage Lithium‐Ion Batteries up to 5.0 V
Authors: Zhao Jianqing , Ellis Sarah , Xie Zhiqiang , Wang Ying
Published: July 2015

Integrated layered‐spinel composite materials are synthesized through the facile decomposition of Li4Mn5O12‐based spinel materials at 900 °C. The intergrowth of spinel Li1+zMn2−zO4 (0<z<0.33) and Li‐rich layered Li2MnO3 components is examined by using X‐ray diffraction and high‐resolution transmission electron microscopy. Such a layered‐spinel composite material and its derivatives obtained by doping transition‐metal ions are evaluated as high‐voltage cathode materials for advanced lithium‐ion batteries up to 5.0 V versus Li/Li+. The Ni‐doped composite cathode shows remarkably high‐energy and high‐power characteristics with high‐voltage plateaus at approximately 4.7 V, delivering desirable discharge capacities of 130, 115, and 90 mAh g−1 at current densities of 25, 125, and 500 mA g−1, respectively, along with excellent cycling stability. This work provides a facile route for preparing the integrated layered‐spinel composite materials as promising high‐voltage cathode materials for lithium‐ion batteries.
Effect of Additives on the Low‐Temperature Stability of Vanadium Redox Flow Battery Negative Half‐Cell Electrolyte
Authors: Mousa Asem , Skyllas‐Kazacos Maria
Published: July 2015

An extensive screening of additives was undertaken to identify precipitation inhibitors to reduce the lower temperature limit of the negative half‐cell electrolyte of the vanadium redox battery. In contrast to the 2 m VII blank solution that precipitated within 16 h at 5.0 °C, in a supporting electrolyte of sulfuric acid with 5 m total sulfates, the induction time for precipitation was more than 46 h in the presence of ammonium phosphate, ammonium sulfate, Flucon‐100, sodium pentapolyphosphate and glycerol. In the case of the 2 m VIII solutions, considerable precipitation was observed after 4 days with 6.5 m total sulfates and the induction time increased to more than 40 days in the presence of ammonium phosphate, ammonium sulfate, sodium pentapolyphosphate and Orotan 1124. Cell cycling experiments confirmed that ammonium phosphate can dramatically extend the cell operation of a 2 m vanadium solution without precipitation over more than 250 cycles at 5 °C, compared with less than 15 cycles for a blank solution without additives.