bluuebunny/crossref_metadata_2025_split huggingface dataset:
TMEDA in Iron‐Catalyzed Kumada Coupling: Amine Adduct versus Homoleptic “ate” Complex Formation
Authors: Bedford Robin B. , Brenner Peter B. , Carter Emma , Cogswell Paul M. , Haddow Mairi F. , Harvey Jeremy N. , Murphy Damien M. , Nunn Joshua , Woodall Christopher H. 
Published: January 2014

AbstractThe reactions of iron chlorides with mesityl Grignard reagents and tetramethylethylenediamine (TMEDA) under catalytically relevant conditions tend to yield the homoleptic “ate” complex [Fe(mes)3]− (mes=mesityl) rather than adducts of the diamine, and it is this ate complex that accounts for the catalytic activity. Both [Fe(mes)3]− and the related complex [Fe(Bn)3]− (Bn=benzyl) react faster with representative electrophiles than the equivalent neutral [FeR2(TMEDA)] complexes. FeI species are observed under catalytically relevant conditions with both benzyl and smaller aryl Grignard reagents. The X‐ray structures of [Fe(Bn)3]− and [Fe(Bn)4]− were determined; [Fe(Bn)4]− is the first homoleptic σ‐hydrocarbyl FeIII complex that has been structurally characterized.
Synthetic Multivalent Glycopeptide‐Lipopeptide Antitumor Vaccines: Impact of the Cluster Effect on the Killing of Tumor Cells
Authors: Cai Hui , Sun Zhan‐Yi , Chen Mei‐Sha , Zhao Yu‐Fen , Kunz Horst , Li Yan‐Mei 
Published: January 2014

AbstractMultivalent synthetic vaccines were obtained by solid‐phase synthesis of tumor‐associated MUC1 glycopeptide antigens and their coupling to a Pam3Cys lipopeptide through click reactions. These vaccines elicited immune responses in mice without the use of any external adjuvant. The vaccine containing four copies of a MUC1 sialyl‐TN antigen showed a significant cluster effect. It induced in mice prevailing IgG2a antibodies, which bind to MCF‐7 breast tumor cells and initiate the killing of these tumor cells by activation of the complement‐dependent cytotoxicity complex.
Mechanism of the Asymmetric Hydrogenation of Exocyclic α,β‐Unsaturated Carbonyl Compounds with an Iridium/BiphPhox Catalyst: NMR and DFT Studies
Authors: Liu Yuanyuan , Gridnev Ilya D. , Zhang Wanbin 
Published: January 2014

AbstractThe mechanism of the asymmetric hydrogenation of exocyclic α,β‐unsaturated carbonyl compounds with the (aS)‐Ir/iPr‐BiphPhox catalyst was studied by NMR experiments and DFT computational analyses. Computed optical yields of the asymmetric hydrogenation proceeding by an iridium(I)/iridium(III) mechanism involving a transition state stabilized through two intramolecular hydrogen bonds are in good accordance with the experimental ee values.
Recent advances in bio‐sourced polymeric carbohydrate/nanotube composites
Authors: Liu Dagang , Zhang Ying , Sun Xun , Chang Peter R. 
Published: January 2014

ABSTRACTNanotubes (NTs), especially carbon nanotubes (CNTs), have attracted much attention in recent years because of their large specific surface area, and their outstanding mechanical, thermal, and electrical properties. In this review we emphasize the development of fascinating properties of polymeric carbohydrate/CNT composites, particularly in terms of their mechanical and conductivity properties and potential applications. Many methods used to modify CNTs during preparation of polymeric carbohydrate/CNT composites are presented. Moreover, we also discuss the enhanced mechanical and electrical effectiveness when hybrid CNTs or halloysite nanotubes were incorporated into different carbohydrate polymer matrices. Finally, we give a future outlook for the development of polymeric carbohydrate/CNT composites as potential alternative materials for various applications including sensors, electroactive paper, electrodes, sorbents for environmental remediation, packaging film, specialty textile, and biomedical devices. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40359.
The cell forming process of microcellular injection‐molded parts
Authors: Dong Guiwei , Zhao Guoqun , Guan Yanjin , Wang Guilong , Wang Xiaoxin 
Published: January 2014

ABSTRACTIn this article, we studied the cell forming process of microcellular injection‐molded parts. Using a modified injection molding machine equipped with a Mucell® SCF delivery system, microcellular‐foamed acrylonitrile–butadiene–styrene parts with different shot sizes were molded. The cell structure on the fractured surfaces along the direction both vertical and parallel to melt flow in the molded parts was examined. The results showed that a regular spherical cells region and a distorted ellipsoidal cells region exist in the molded parts simultaneously. The length of the distorted cells region along the melt flow direction in the molded parts remained basically unchanged for different shot sizes and it is about 195 mm away from the flow front in this study's conditions. The cell formation mechanism was analyzed, two cell forming processes in microcellular injection molding, the “foam during filling” process and the “foam after filling” process, were proposed. It was also found that the melt pressure in the filling stage is the dominant factor affecting the cell forming process, and there is a critical melt pressure value in the filling stage, 20.9 MPa, as the dividing line of the two cell forming processes in this study. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40365.
Improvement in impact strength of modified cardanol‐bonded cellulose thermoplastic resin by adding modified silicones
Authors: Soyama Makoto , Kiuchi Yukihiro , Iji Masatoshi , Tanaka Shukichi , Toyama Kiyohiko 
Published: January 2014

ABSTRACTThe impact strength of cellulose diacetate (CDA) bonded with a modified cardanol (3‐pentadecylphenoxy acetic acid: PAA) was greatly improved up to 9 kJ/m2 by adding a relatively small amount of modified silicones while suppressing a decrease in bending strength. In our recent research, this thermoplastic resin (PAA‐bonded CDA) exhibited high rigidity, glass transition temperature, and water resistance. However, its impact strength was insufficient for use in durable products. Therefore, silicones modified with polyether, amino, and epoxy groups were investigated as possible ways to improve the impact strength. The results show that adding polyether‐modified silicone (polyether silicone) with moderate polarity relative to PAA‐bonded CDA resulted in shearing deformation greatly enhances its impact strength while maintaining other properties, including glass transition temperature (Tg), water resistance, and thermoplasticity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40366.
Eco‐friendly, acrylic resin‐modified potassium silicate as water‐based vehicle for anticorrosive zinc‐rich primers
Authors: Goodarzi Iman Mirzaie , Farzam Mansour , Shishesaz Mohammad Reza , Zaarei Davood 
Published: January 2014

ABSTRACTPotassium silicate binder of zinc‐rich coating was modified by adding water‐based acrylic resin. Several series of coatings containing 5, 10, and 15 wt % of acrylic and acrylic/styrene binders were added to potassium silicate. The coatings were applied on steel and the corrosion resistance of coatings was evaluated by conventional methods such as electrochemical impedance spectroscopy, corrosion potential, salt spray, and scanning electron microscopy. The results indicated that the modification of silicate binder with acrylic and acrylic/styrene led to shortening the curing time, improved corrosion protection, better dispersion of zinc particles, and enhanced salt spray resistance of resultant coatings. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40370.
Conformationally Restricted Aza‐Dipyrromethene Boron Difluorides (Aza‐BODIPYs) with High Fluorescent Quantum Yields
Authors: Jiao Lijuan , Wu Yayang , Ding Yin , Wang Sufan , Zhang Ping , Yu Changjiang , Wei Yun , Mu Xiaolong , Hao Erhong 
Published: January 2014

AbstractA simple approach to the highly fluorescent near‐infrared aza‐BODIPY dyes with higher fluorescence quantum yields (up to 0.81 in toluene) in comparison with their known analogues is presented. Our approach is based on the restricted rotations of the 1,7‐phenyl groups to the mean plane of the aza‐BODIPYs, which is achieved through the installation of bulky substituents on the 1,7‐phenyl groups of aza‐BODIPYs and results in a reduced nonradiative relaxation process in solution. The large torsion angles between the 1,7‐phenyl groups and the aza‐BODIPY core (ϕ1 and ϕ2 in these novel conformationally restricted aza‐BODIPYs) were confirmed by X‐ray diffraction studies.
Self‐Assembly of π‐Conjugated Gelators into Emissive Chiral Nanotubes: Emission Enhancement and Chiral Detection
Authors: Wang Xiufeng , Duan Pengfei , Liu Minghua 
Published: January 2014

AbstractA series of new π‐conjugated gelators that contain various aromatic rings (phenyl, naphthyl, 9‐anthryl) and amphiphilic L‐glutamide was designed, and their gel formation in organic solvents and self‐assembled nanostructures was investigated. The gelators showed good gelation ability in various organic solvents that ranged from polar to nonpolar. Those gelator molecules with small rings such as phenyl and naphthyl self‐assembled into nanotube structures in most organic solvents and showed strong blue emission. However, the 9‐anthryl derivative formed only a nanofiber structure in any organic solvent, probably owing to the larger steric hindrance. All of these gels showed enhanced fluorescence in organogels. Furthermore, during the gel formation, the chirality at the L‐glutamide moiety was transferred to the nanostructures, thus leading to the formation of chiral nanotubes. One of the nanotubes showed chiral recognition toward the chiral amines.
Bridge‐Localized HOMO‐Binding Character of Divinylanthracene‐Bridged Dinuclear Ruthenium Carbonyl Complexes: Spectroscopic, Spectroelectrochemical, and Computational Studies
Authors: Ou Ya‐Ping , Zhang Jing , Xu Meng , Xia Jianlong , Hartl František , Yin Jun , Yu Guang‐Ao , Liu Sheng Hua 
Published: January 2014

AbstractThe electronic properties of four divinylanthracene‐bridged diruthenium carbonyl complexes [{RuCl(CO)(PMe3)3}2(μCHCHArCHCH)] (Ar=9,10‐anthracene (1), 1,5‐anthracene (2), 2,6‐anthracene (3), 1,8‐anthracene (4)) obtained by molecular spectroscopic methods (IR, UV/Vis/near‐IR, and EPR spectroscopy) and DFT calculations are reported. IR spectroelectrochemical studies have revealed that these complexes are first oxidized at the noninnocent bridging ligand, which is in line with the very small ν(CO) wavenumber shift that accompanies this process and also supported by DFT calculations. Because of poor conjugation in complex 1, except oxidized 1+, the electronic absorption spectra of complexes 2+, 3+, and 4+ all display the characteristic near‐IR band envelopes that have been deconvoluted into three Gaussian sub‐bands. Two of the sub‐bands belong mainly to metal‐to‐ligand charge‐transfer (MLCT) transitions according to results from time‐dependent DFT calculations. EPR spectroscopy of chemically generated 1+–4+ proves largely ligand‐centered spin density, again in accordance with IR spectra and DFT calculations results.
Identification and analysis of novel R308K mutation in glucokinase of type 2 diabetic patient and its kinetic correlation
Authors: Yellapu Nanda Kumar , Valasani Koteswara Rao , Pasupuleti Santhosh Kumar , Gopal Sowjenya , Potukuchi Venkata Gurunadha Krishna Sarma , Matcha Bhaskar 
Published: January 2014

AbstractGlucokinase (GK) plays a critical role in glucose homeostasis and the mutations in GK gene result in pathogenic complications known as Maturity Onset Diabetes of the Young 2, an autosomal dominant form of diabetic condition. In the present study, GK was purified from human liver tissue and the pure enzyme showed single band in SDS‐PAGE with a molecular weight of 50 kDa. The kinetics of pure GK showed enzyme activity of 0.423 ± 0.02 µM glucose‐6‐phosphate (G6P)/mL/Min and Km value of 6.66 ± 0.02 µM. These values were compared in the liver biopsy of a clinically proven type 2 diabetic patient, where GK kinetics showed decreased enzyme activity of 0.16 ± 0.025 µM G6P/mL/Min and increased Km of 23 ± 0.9 µM, indicating the hyperglycemic condition in the patient. The genetic analysis of 10th exon of GK gene from this patient showed a R308K mutation. To substantiate these results, comparative molecular dynamics and docking studies were carried out where a higher docking score (−10.218 kcal/mol) was observed in the mutated GK than wild‐type GK structure (−12.593 kcal/mol) indicating affinity variations for glucose. During the simulation process, glucose was expelled out from the mutant conformation but not from wild‐type GK, making glucose unavailable for phosphorylation. Therefore, these results conclusively explain hyperglycemic condition in this patient.
Redox‐Driven Host–Guest Interactions Allow the Controlled Release of Captured Cells on RGD‐Functionalized Surfaces
Authors: Thakar Dhruv , Coche‐Guérente Liliane , Claron Michaël , Wenk Christiane H. F. , Dejeu Jérôme , Dumy Pascal , Labbé Pierre , Boturyn Didier 
Published: January 2014

AbstractA quartz crystal microbalance technique with dissipation monitoring and a complementary optical microscopy technique were used for monitoring the capture and release of specific cells on a surface displaying a bifunctional molecular device, composed of a molecular scaffold endowed with the cell recognition property of an RGD ligand and a β‐CD/Fc redox‐switchable system.
An Integrated Computational and Experimental Approach to Gaining Selectivity for MMP‐2 within the Gelatinase Subfamily
Authors: Fabre Benjamin , Filipiak Kamila , Díaz Natalia , Zapico José María , Suárez Dimas , Ramos Ana , de Pascual‐Teresa Beatriz 
Published: January 2014

AbstractLooking for water‐soluble inhibitors of matrix metalloproteinase‐2 (MMP‐2 or gelatinase A), we have previously reported compound 1, a potent MMP‐2 inhibitor with a promising selectivity over the structurally homologous MMP‐9 (gelatinase B). Here we report the results of Molecular Dynamics (MD) simulations for both gelatinases (MMP‐2 and MMP‐9), and for the corresponding MMP/1 complexes, in an attempt to shed light on the observed selectivity between the two enzymes. These studies indicated a higher plasticity of MMP‐2 at the S1′ pocket and suggested an induced‐fit effect at the “back door” of this pocket. On the basis of these observations, we designed 11 a–d to aid further discrimination between MMP‐2 and MMP‐9. Those compounds displayed notably lower inhibitory activities against MMP‐9; in particular, 11 b proved to be over 100 times more active against MMP‐2 than against MMP‐9. MD simulations of the MMP/11 b complexes and thermodynamic integration calculations provided structural insight and relative binding energies consistent with the experimentally observed activity data. These findings demonstrate that structural differences in the S1′ pocket bottom permit an improvement in selectivity in the inhibition of MMP‐2 over that of MMP‐9; this is of great relevance for future structure‐based drug design because MMP‐2 is a validated target for cancer therapy, whereas MMP‐9 plays both detrimental and protective roles in cancer. This study also supports the need to consider the dynamics of the S1′ pocket in order to achieve selectivity in the inhibition of MMPs.
NecroX‐5 suppresses sodium nitroprusside‐induced cardiac cell death through inhibition of JNK and caspase‐3 activation
Authors: Lee Sung Ryul , Lee Seon Joong , Kim Soon Ha , Ko Kyung Soo , Rhee Byoung Doo , Xu Zhelong , Kim Nari , Han Jin 
Published: January 2014

AbstractAlthough sodium nitroprusside (SNP) is an effective hypotensive drug and is often used in pediatric intensive care units and to treat acute heart failure, clinical application of SNP is limited by its cardiotoxicity. NecroX‐5 (NX‐5) was recently developed and has the capacity to inhibit necrotic cell death. No current literature addresses whether NX‐5 suppresses SNP‐induced cell death or its mechanism of action. We have investigated the protective role of NX‐5 against SNP‐induced cell death in cardiomyocyte‐like H9c2 cells. SNP treatment induced severe cell death, possibly through phosphorylation of stress‐activated protein kinase/c‐Jun NH2‐terminal kinase (JNK) and activation of the apoptotic signaling pathway, including downregulation of Bcl‐2 and cleavage of caspase‐3. However, NX‐5 suppresses SNP‐induced cell death through inhibition of JNK activation and suppression of both downregulation of Bcl‐2 protein expression and caspase‐3 cleavage. These findings will provide insights and facilitate development of antidotes to SNP toxicity in cardiac cells.
Creation of Brønsted Acidity by Grafting Aluminum Isopropoxide on Silica under Controlled Conditions: Determination of the Number of Brønsted Sites and their Turnover Frequency for m‐Xylene Isomerization
Authors: Caillot Maxime , Chaumonnot Alexandra , Digne Mathieu , Van Bokhoven Jeroen A. 
Published: January 2014

AbstractThere is not a unique Brønsted acid site for aluminosilicates (ASAs). IR spectroscopy following CO adsorption proves the creation of Brønsted acid sites on Al/SiO2 ASAs, which are synthesized by the deposition of aluminum species on hydroxylated silica. These sites are active for ethanol dehydration and m‐xylene isomerization. Controlled deposition under anhydrous conditions optimizes the number of sites, whereas the presence of water leads to alumina agglomerates with no Brønsted acidity. The turnover frequency for m‐xylene isomerization (4.3×10−4 s−1 site−1 at 350 °C, atmospheric pressure, and 0.6 cm3 h−1 of m‐xylene) is approximately 3 times lower than that of the Brønsted acid sites of Si/Al2O3 and 75 times lower than that of an ultrastable Y‐type zeolite without extra‐framework aluminum.
Bismuth‐Based Pervoskite as a High‐Performance Cathode for Intermediate‐Temperature Solid‐Oxide Fuel Cells
Authors: Huang Shouguo , Gao Feng , Meng Zheng , Feng Shuangjiu , Sun Xiaohong , Li Yide , Wang Chunchang 
Published: January 2014

AbstractA new bismuth‐based perovskite cathode material, Bi0.5Sr0.5Fe0.8Co0.2O3−δ (BiSFC), showing not only low area‐specific resistance but also a low thermal expansion coefficient, exhibits excellent electrochemical catalytic activity for the oxygen reduction reaction in the application of intermediate‐temperature solid‐oxide fuel cells (ITSOFCs). The high performance implies that BiSFC is a very promising cathode material for ITSOFCs.
First‐Principles Modeling of Electrochemical Water Oxidation on MnO:ZnO(001)
Authors: Kanan Dalal K. , Keith John A. , Carter Emily A. 
Published: January 2014

AbstractThe demand for renewable hydrogen derived from CO2‐neutral water‐splitting processes spurs efforts to develop new catalysts, including those inspired by nature. A first‐principles quantum mechanics (Kohn–Sham density functional theory + U) approach has been used to model electrocatalytic water oxidation on the visible‐light‐absorbing transition‐metal oxide alloy, MnO:ZnO; a material that can be considered a heterogeneous analogue to the photosystem II photocatalyst. Ab‐initio‐derived U values were used to correct self‐interaction errors in the highly correlated material. It has been confirmed that previously established scaling relationships between the binding energies of reaction intermediates are valid. The predicted electrochemical overpotential for water oxidation under experimentally relevant conditions (0.82 V versus the standard hydrogen electrode) is slightly higher than those values reported for manganese oxides and comparable to those previously calculated values for hematite photoanodes.
Phenothiazine‐Capped Gold Nanoparticles: Photochemically Assisted Synthesis and Application in Electrosensing of Phosphate Ions
Authors: Gupta Sandeep , Singh Akhilesh K. , Jain Ravish K. , Chandra Ramesh , Prakash Rajiv 
Published: January 2014

AbstractWe describe a green photochemical route for the synthesis of gold nanoparticles (AuNPs) using phenothiazine (PTZH) as a reductant as well as a stabilizer without any extra control (i.e. surfactant, pH, etc.). The synthesized AuNPs are characterized by using UV/Vis spectroscopy, cyclic voltammetry, and transmission electron microscopy. Furthermore, a possible mechanism for the formation of the AuNPs is proposed. This hybrid electrode material, derived from nanoscale gold particles capped with PTZH and its oxidation product, is explored for the development of a highly sensitive amperometric sensor for phosphate ions. The electrochemistry behind the electrocatalytic sensing of phosphate is attributed to the nano‐sized gold particles that are capped with PTZH and its oxidation product, which exhibit high electron‐transfer kinetics through the interaction of the hybrid PTZH–AuNPs with oxygen atoms of ${{\rm{PO}}_4^{3 - } }$. The modified electrode efficiently gives an electrochemical signature of phosphate ions at a potential of −0.336 V versus AgCl/Ag and shows a linear response toward phosphate sensing, with a sensitivity of 0.794 μA μM−1 and a limit of detection of 0.022 μm, at a signal‐to‐noise ratio of 3.
Simultaneous Electrochemical Detection of Silver and Molybdenum Nanoparticles
Authors: Goda Tatsuro , Ambrosi Adriano , Miyahara Yuji , Pumera Martin 
Published: January 2014

AbstractNanoparticles (NPs) and quantum dots (QDs) are of interest as redox tags in electrochemical biosensing. Simultaneous monitoring of the redox reactions of these tags with different redox potentials under mild conditions may allow the multiplex detection of target analytes in point‐of‐care applications. The multiplex detection of Ag and Mo NPs on a glassy carbon electrode is investigated under mild aqueous conditions (pH 7.2) by using differential pulse voltammetry. The separation in the oxidative peaks allows us to successfully quantify each component of the NPs at a time. The redox signals are proportional to the amount of each NP, with the dynamic ranges of 0.313 to 10 ng for Ag NP and 31.3 to 500 ng for Mo NP on the working electrode. The electrochemical features of these NPs meet the requirements of redox tags for multiplex sensing schemes, without the need for NP dissolution by using strong acid and base reagents.
The Development of Copper‐Catalyzed Aerobic Oxidative Coupling of H‐Tetrazoles with Boronic Acids and an Insight into the Reaction Mechanism
Authors: Liu Chao‐You , Li Yu , Ding Jin‐Ying , Dong De‐Wen , Han Fu‐She 
Published: January 2014

AbstractThe development of a highly efficient and practical protocol for the direct CN coupling of H‐tetrazole and boronic acid was presented. A careful and patient optimization of a variety of reaction parameters revealed that this conventionally challenge reaction could indeed proceed efficiently in a very simple system, that is, just by stirring the tetrazoles and boronic acids under oxygen in the presence of different CuI or CuII salts with only 5 mol % loading in DMSO at 100 °C. Most significantly, the reaction could proceed very smoothly in a regiospecific manner to afford the 2,5‐disubstituted tetrazoles in high to excellent yields. A mechanistic study revealed that both tetrazole and DMSO are crucial for the generation of catalytically active copper species in the reaction process in addition to their role as reactant and solvent, respectively. It is demonstrated that in the reaction cycle, the CuI catalyst could be oxidized to CuII by oxygen to form a [CuT2D] complex (T=tetrazole anion; D=DMSO) through an oxidative copper amination reaction. The CuII complex thus formed was confirmed to be the real catalytically active copper species. Namely, the CuII complex disproportionates to aryl CuIII and CuI in the presence of boronic acid. Facile elimination of the CuIII species delivers the CN‐coupled product. The results presented herein not only provide a reliable and efficient protocol for the synthesis of 2,5‐disubstituted tetrazoles, but most importantly, the mechanistic results would have broad implications for the de novo design and development of new methods for Cu‐catalyzed coupling reactions.