bluuebunny/crossref_metadata_2025_split huggingface dataset:
Small‐Molecule Proteomimetic Inhibitors of the HIF‐1α–p300 Protein–Protein Interaction
Authors: Burslem George M. , Kyle Hannah F. , Breeze Alexander L. , Edwards Thomas A. , Nelson Adam , Warriner Stuart L. , Wilson Andrew J. 
Published: April 2014

AbstractThe therapeutically relevant hypoxia inducible factor HIF‐1α–p300 protein–protein interaction can be orthosterically inhibited with α‐helix mimetics based on an oligoamide scaffold that recapitulates essential features of the C‐terminal helix of the HIF‐1α C‐TAD (C‐terminal transactivation domain). Preliminary SAR studies demonstrated the important role of side‐chain size and hydrophobicity/hydrophilicity in determining potency. These small molecules represent the first biophysically characterised HIF‐1α–p300 PPI inhibitors and the first examples of small‐molecule aromatic oligoamide helix mimetics to be shown to have a selective binding profile. Although the compounds were less potent than HIF‐1α, the result is still remarkable in that the mimetic reproduces only three residues from the 42‐residue HIF‐1α C‐TAD from which it is derived.
Involvement of SgvP in Carbon–Sulfur Bond Formation during Griseoviridin Biosynthesis
Authors: Xie Yunchang , Li Qinglian , Song Yongxiang , Ma Junying , Ju Jianhua 
Published: April 2014

AbstractGriseoviridin (GV) is an A‐type streptogramin antibiotic displaying antimicrobial activity and acting synergistically with viridogrisein (VG). Bioinformatic analyses reveal SgvP as the sole cytochrome P450 enzyme in the GV/VG gene cluster. To explore the role of SgvP in the GV/VG pathway, we inactivated the sgvP gene. The resulting ΔsgvP mutant generated two new products: GV‐1 and GV‐2, both lacking the CS bridge. In trans complementation of the sgvP gene into the ΔsgvP mutant strain partially restores GV production. Feeding [1‐13C]‐labeled cysteine to the wild‐type strain led to enrichment of C‐7 in the GV scaffold, thus verifying that the CS bond in GV is formed through direct coupling of the free SH group provided by the side chain of cysteine. The above results highlight the significance of SgvP in CS bond formation in griseoviridin biosynthesis.
Magnifying the Morphology Change Induced by a Nickel Promoter in Tungsten(IV) Sulfide Industrial Hydrocracking Catalyst: A HAADF‐STEM and DFT Study
Authors: Girleanu Maria , Alphazan Thibault , Boudene Zoubeyr , Bonduelle‐Skrzypczak Audrey , Legens Christèle , Gay Anne‐Sophie , Copéret Christophe , Ersen Ovidiu , Raybaud Pascal 
Published: April 2014

AbstractChanges in the two‐dimensional (2D) morphology of nonpromoted WS2 and Ni‐promoted WS2 (NiWS) catalytically active nanolayers supported on amorphous silica‐alumina (ASA) are revealed by aberration‐corrected scanning transmission electron microscopy and rationalized by density functional theory calculations. The presence of the Ni atoms modifies the triangular shape of nonpromoted WS2/ASA nanolayers into a more hexagonal one for NiWS/ASA by stabilizing the S edge more strongly than the W edge. The higher catalytic activity induced by the addition of the promoter confirms the relevance of such a morphology effect for industrial catalysts.
Three‐Dimensional Structural Engineering for Energy‐Storage Devices: From Microscope to Macroscope
Authors: Xu Jing , Wang Xianfu , Wang Xiaowei , Chen Di , Chen Xiaoyuan , Li Dongdong , Shen Guozhen 
Published: April 2014

AbstractFor high‐performance energy‐storage devices, three‐dimensional (3D) designs with diverse configurations are demonstrated to provide highly qualified electrodes and efficient device integration. From a microscope to a macroscope view, this review summarizes the recent advances in electrochemically active nanomaterials, novel current collectors, and integrations of the devices in 3D configurations.
The Nature of the Fourth Bond in the Ground State of C2: The Quadruple Bond Conundrum
Authors: Danovich David , Hiberty Philippe C. , Wu Wei , Rzepa Henry S. , Shaik Sason 
Published: April 2014

AbstractDoes, or doesn’t C2 break the glass ceiling of triple bonding? This work provides an overview on the bonding conundrum in C2 and on the recent discussions regarding our proposal that it possesses a quadruple bond. As such, we focus herein on the main point of contention, the 4th bond of C2, and discuss the main views. We present new data and an overview of the nature of the 4th bond—its proposed antiferromagnetically coupled nature, its strength, and a derivation of its bond energy from experimentally based thermochemical data. We address the bond‐order conundrum of C2 arising from generalized VB (GVB) calculations by comparing it to HCCH, and showing that the two molecules behave very similarly, and C2 is in no way an exception. We analyse the root cause of the deviation of C2 from the Badger Rule, and demonstrate that the reason for the smaller force constant (FC) of C2 relative to HCCH has nothing to do with the bond energies, or with the number of bonds in the two molecules. The FC is determined primarily by the bond length, which is set by the balance between the bond length preferences of the σ‐ versus π‐bonds in the two molecules. This interplay in the case of C2 clearly shows the fingerprints of the 4th bond. Our discussion resolves the points of contention and shows that the arguments used to dismiss the quadruple bond nature of C2 are not well founded.
Binding of a Ruthenium Complex to a Thioether Ligand Embedded in a Negatively Charged Lipid Bilayer: A Two‐Step Mechanism
Authors: Bahreman Azadeh , Rabe Martin , Kros Alexander , Bruylants Gilles , Bonnet Sylvestre 
Published: April 2014

AbstractThe interaction between the ruthenium polypyridyl complex [Ru(terpy)(dcbpy)(H2O)]2+ (terpy=2,2′;6′,2“‐terpyridine, dcbpy=6,6′‐dichloro‐2,2′‐bipyridine) and phospholipid membranes containing either thioether ligands or cholesterol were investigated using UV–visible spectroscopy, Langmuir–Blodgett monolayer surface pressure measurements, and isothermal titration calorimety (ITC). When embedded in a membrane, the thioether ligand coordinated to the dicationic metal complex only when the phospholipids of the membrane were negatively charged, that is, in the presence of attractive electrostatic interaction. In such a case coordination is much faster than in homogeneous conditions. A two‐step model for the coordination of the metal complex to the membrane‐embedded sulfur ligand is proposed, in which adsorption of the complex to the negative surface of the monolayers or bilayers occurs within minutes, whereas formation of the coordination bond between the surface‐bound metal complex and ligand takes hours. Finally, adsorption of the aqua complex to the membrane is driven by entropy. It does not involve insertion of the metal complex into the hydrophobic lipid layer, but rather simple electrostatic adsorption at the water–bilayer interface.
Ruthenium Complexes of an Abnormally Bound, Anionic N‐Heterocyclic Carbene
Authors: Pranckevicius Conor , Stephan Douglas W. 
Published: April 2014

AbstractThe abnormally bound, anionic NHC–borane complex [Ru(IDipp‐BF3)(p‐cymene)Cl]2 (4; IDipp‐BF3=1,3‐(2,6‐iPr2C6H3)2‐2‐BF3(C3HN2)‐4‐yl) was synthesized by transmetalation from Li[(IDipp‐BF3)2Ag]. Addition of donors gave species of the form [Ru(IDipp‐BF3)(p‐cymene)(L)Cl], whereas halide abstraction with Ag(Et2O)[B(C6F5)4] gave CH activation of the methine position of the IDippBF3 ligand.
Synthesis of Cyclobutenes and Allenes by Cobalt‐Catalyzed Cross‐Dimerization of Simple Alkenes with 1,3‐Enynes
Authors: Nishimura Akira , Tamai Eri , Ohashi Masato , Ogoshi Sensuke 
Published: April 2014

AbstractCobalt‐catalyzed cross‐dimerization of simple alkenes with 1,3‐enynes is reported. A [2+2] cycloaddition reaction occurred, with alkenes bearing no allylic hydrogen, by reductive elimination of a η3‐butadienyl cobaltacycle. On the other hand, aliphatic alkenes underwent 1,4‐hydroallylation by means of exo‐cyclic β‐H elimination. These reactions can provide cyclobutenes and allenes that were previously difficult to access, from simple substrates in a highly chemo‐ and regioselective manner.
Evidence of Noncentrosymmetry of Human Tooth Hydroxyapatite Crystals
Authors: Mugnaioli Enrico , Reyes‐Gasga José , Kolb Ute , Hemmerlé Joseph , Brès Étienne F. 
Published: April 2014

AbstractHerein, we investigate human single hydroxyapatite crystals (enamel and dentine) by convergent‐beam electron diffraction (CBED) and automated electron‐diffraction tomography (ADT). The CBED pattern shows the absence of the mirror plane perpendicular to the c axis leading to the P63 space group instead of the P63/m space group considered for larger‐scale crystals, this is confirmed by ADT. This experimental evidence is of prime importance for understanding the morphogenesis and the architectural organization of calcified tissues.
Linking an α‐Tocopherol Derivative to Cobalt(0) Nanomagnets: Magnetically Responsive Antioxidants with Superior Radical Trapping Activity and Reduced Cytotoxicity
Authors: Viglianisi Caterina , Di Pilla Veronica , Menichetti Stefano , Rotello Vincent M. , Candiani Gabriele , Malloggi Chiara , Amorati Riccardo 
Published: April 2014

AbstractCovalent attachment of a phenolic antioxidant analogue of α‐tocopherol to graphite‐coated magnetic cobalt nanoparticles (CoNPs) provided a novel magnetically responsive antioxidant capable of preventing the autoxidation of organic materials and showing a reduced toxicity toward human cells.
Asymmetric Synthesis of Fortucine and Reassignment of Its Absolute Configuration
Authors: Beaulieu Marc‐André , Ottenwaelder Xavier , Canesi Sylvain 
Published: April 2014

AbstractA convergent and enantioselective synthesis of fortucine was achieved from the starting materials tyrosine methyl ester and 3‐hydroxy‐4‐methoxybenzaldehyde. The synthesis is based on two key steps mediated by a hypervalent iodine reagent. This work has enabled us to reassign the absolute configuration of the natural product reported in the literature.
Solvent‐Dependent Cation Exchange in Metal–Organic Frameworks
Authors: Brozek Carl K. , Bellarosa Luca , Soejima Tomohiro , Clark Talia V. , López Núria , Dincă Mircea 
Published: April 2014

AbstractWe investigated which factors govern the critical steps of cation exchange in metal–organic frameworks by studying the effect of various solvents on the insertion of Ni2+ into MOF‐5 and Co2+ into MFU‐4l. After plotting the extent of cation insertion versus different solvent parameters, trends emerge that offer insight into the exchange processes for both systems. This approach establishes a method for understanding critical aspects of cation exchange in different MOFs and other materials.
Two‐Dimensional Tetrathiafulvalene Covalent Organic Frameworks: Towards Latticed Conductive Organic Salts
Authors: Jin Shangbin , Sakurai Tsuneaki , Kowalczyk Tim , Dalapati Sasanka , Xu Fei , Wei Hao , Chen Xiong , Gao Jia , Seki Shu , Irle Stephan , Jiang Donglin 
Published: April 2014

AbstractThe construction of a new class of covalent TTF lattice by integrating TTF units into two‐dimensional covalent organic frameworks (2D COFs) is reported. We explored a general strategy based on the C2+C2 topological diagram and applied to the synthesis of microporous and mesoporous TTF COFs. Structural resolutions revealed that both COFs consist of layered lattices with periodic TTF columns and tetragonal open nanochannels. The TTF columns offer predesigned pathways for high‐rate hole transport, predominate the HOMO and LUMO levels of the COFs, and are redox active to form organic salts that exhibit enhanced electric conductivity by several orders of magnitude. On the other hand, the linkers between the TTF units play a vital role in determining the carrier mobility and conductivity through the perturbation of 2D sheet conformation and interlayer distance. These results open a way towards designing a new type of TTF materials with stable and predesignable lattice structures for functional exploration.
Development of 3‐Phenyl‐N‐(2‐(3‐phenylureido)ethyl)‐thiophene‐2‐sulfonamide Compounds as Inhibitors of Antiapoptotic Bcl‐2 Family Proteins
Authors: Yang Chengwen , Chen Sha , Zhou Mi , Li Yan , Li Yangfeng , Zhang Zhengxi , Liu Zhen , Ba Qian , Li Jingquan , Wang Hui , Yan Xiaomei , Ma Dawei , Wang Renxiao 
Published: April 2014

AbstractAntiapoptotic Bcl‐2 family proteins, such as Bcl‐xL, Bcl‐2, and Mcl‐1, are often overexpressed in tumor cells, which contributes to tumor cell resistance to chemotherapies and radiotherapies. Inhibitors of these proteins thus have potential applications in cancer treatment. We discovered, through structure‐based virtual screening, a lead compound with micromolar binding affinity to Mcl‐1 (inhibition constant (Ki)=3 μM). It contains a phenyltetrazole and a hydrazinecarbothioamide moiety, and it represents a structural scaffold not observed among known Bcl‐2 inhibitors. This work presents the structural optimization of this lead compound. By following the scaffold‐hopping strategy, we have designed and synthesized a total of 82 compounds in three sets. All of the compounds were evaluated in a fluorescence‐polarization binding assay to measure their binding affinities to Bcl‐xL, Bcl‐2, and Mcl‐1. Some of the compounds with a 3‐phenylthiophene‐2‐sulfonamide core moiety showed sub‐micromolar binding affinities to Mcl‐1 (Ki=0.3–0.4 μM) or Bcl‐2 (Ki≈1 μM). They also showed obvious cytotoxicity on tumor cells (IC50<10 μM). Two‐dimensional heteronuclear single quantum coherence NMR spectra of three selected compounds, that is, YCW‐E5, YCW‐E10, and YCW‐E11, indicated that they bind to the BH3‐binding groove on Bcl‐xL in a similar mode to ABT‐737. Several apoptotic assays conducted on HL‐60 cells demonstrated that these compounds are able to induce cell apoptosis through the mitochondrial pathway. We propose that the compounds with the 3‐phenylthiophene‐2‐sulfonamide core moiety are worth further optimization as effective apoptosis inducers with an interesting selectivity towards Mcl‐1 and Bcl‐2.
Monoamine Oxidase (MAO) Inhibitory Activity: 3‐Phenylcoumarins versus 4‐Hydroxy‐3‐phenylcoumarins
Authors: Delogu Giovanna L. , Serra Silvia , Quezada Elias , Uriarte Eugenio , Vilar Santiago , Tatonetti Nicholas P. , Viña Dolores 
Published: April 2014

AbstractMonoamine oxidase (MAO) is a useful target in the treatment of neurodegenerative diseases and depressive disorders. Both isoforms, MAO‐A and MAO‐B, are known to play critical roles in disease progression, and as such, the identification of novel, potent and selective inhibitors is an important research goal. Here, two series of 3‐phenylcoumarin derivatives were synthesized and evaluated against MAO‐A and MAO‐B. Most of the compounds tested acted preferentially on MAO‐B, with IC50 values in the micromolar to nanomolar range. Only 6‐chloro‐4‐hydroxy‐3‐(2’‐hydroxyphenyl)coumarin exhibited activity against the MAO‐A isoform, while still retaining good selectivity for MAO‐B. 6‐Chloro‐3‐phenylcoumarins unsubstituted at the 4 position were found to be more active as MAO‐B inhibitors than the corresponding 4‐hydroxylated coumarins. For 4‐unsubstituted coumarins, meta and para positions on the 3‐phenyl ring seem to be the most favorable for substitution. Molecular docking simulations were used to explain the observed hMAO‐B structure–activity relationships for this type of compound. 6‐Chloro‐3‐(3’‐methoxyphenyl)coumarin was the most active compound identified (IC50=0.001 μM) and is several times more potent and selective than the reference compound, R‐(−)‐deprenyl hydrochloride. This compound represents a novel tool for the further investigation of the therapeutic potential of MAO‐B inhibitors.
Science gateway technologies for the astrophysics community
Authors: Becciani Ugo , Sciacca Eva , Costa Alessandro , Massimino Piero , Pistagna Costantino , Riggi Simone , Vitello Fabio , Petta Catia , Bandieramonte Marilena , Krokos Mel 
Published: April 2014

SummaryThe availability of large‐scale digital surveys offers tremendous opportunities for advancing scientific knowledge in the astrophysics community. Nevertheless, the analysis of these data often requires very powerful computational resources. Science gateway technologies offer Web‐based environments to run applications with little concern for learning and managing the underlying infrastructures that execute them. This paper focuses on the issues related to the development of a science gateway customized for the needs of the astrophysics community. The VisIVO Science Gateway is wrapped around a WS‐PGRADE/grid User Support Environment portal integrating services for processing and visualizing large‐scale multidimensional astrophysical data sets on distributed computing infrastructures. We discuss the core tools and services supported including an application for mobile access to the gateway. We report our experiences in supporting specialized astrophysical communities requiring development of complex workflows for visualization and numerical simulations. Further, available platforms are discussed for sharing workflows in collaborative environments. Finally, we outline our vision for creating a federation of science gateways to benefit astrophysical communities by sharing a set of services for authentication, computing infrastructure access and data/workflow repositories. Copyright © 2014 John Wiley & Sons, Ltd.
Efficient privacy preserving matchmaking for mobile social networking
Authors: Wang Yong , Hou Jie , Xia Yun , Li Hong‐zong 
Published: April 2014

SummaryDiscovering new friends who share common attributes, named as matchmaking, is one of the most popular applications in mobile social networking. The key security issue in matchmaking is to protect users' personal information. In this paper, we propose a novel privacy preserving matchmaking framework, which can help users to find new friends in mobile social networking without leaking their privacy information. A user (called initiator) can find the one who shares maximum number of common attributes with him (called best match) among nearby users (called candidates), and only exchange an attribute intersection set with the best match, while other candidates only know the size of the attribute intersection set mutually. The analysis and simulation results show that our protocol can resist both semi‐honest and malicious attacks while providing efficient matchmaking functionality. Copyright © 2014 John Wiley & Sons, Ltd.
Improving the program performance through prioritized memory management and disk operation
Authors: Yeh Tsozen , Yang Shuwen , Sun Yifeng 
Published: April 2014

SummaryComputers are indispensable to modern human society. Often, computers host multiple programs running simultaneously. However, among those programs, some maybe more time critical than others to users. Consequently, users would hope those time‐critical programs to finish their execution as soon as possible. Generally speaking, the course of program execution includes cooperative operation of CPU, memory, and hard disk. For CPU operation, modern computer systems have the ability to adjust the CPU scheduling sequence according to program priority. Nevertheless, most of them do not have effective ways to provide memory management and disk operation based on program priority. Consequently, it is hard to speed up the execution of prioritized programs as users would expect. The Linux operating system has been widely used in recent years. Even though it still does not support fully‐prioritized memory management and disk operation. Previously, based on the default Linux disk scheduler, complete fair queuing (CFQ), we proposed a new disk scheduling algorithm called prioritized CFQ (PCFQ) to provide fully‐prioritized disk operation. PCFQ had demonstrated good performance improvement for programs with high priority. In this paper, we report our effort to integrate PCFQ with prioritized memory management as a whole in the Linux operating system. With the cooperation between prioritized memory management and prioritized disk operation, our system further enhanced the performance that PCFQ achieved by up to 62.08%. Experimental results also showed that, compared with the current Linux system, our design can lift the performance of individual prioritized programs by up to 76.63% when there was one prioritized program on the system. The number went up to 82.45% when the system hosted three programs with high priority.Concurrency and Computation: Practice and Experience.Copyright © 2014 John Wiley & Sons, Ltd.
Quantum Chemical Studies on Solvents for Post‐Combustion Carbon Dioxide Capture: Calculation of pKa and Carbamate Stability of Disubstituted Piperazines
Authors: Gangarapu Satesh , Wierda Gerben J. , Marcelis Antonius T. M. , Zuilhof Han 
Published: April 2014

AbstractPiperazine is a widely studied solvent for post‐combustion carbon dioxide capture. To investigate the possibilities of further improving this process, the electronic and steric effects of CH3, CH2F, CH2OH, CH2NH2, COCH3, and CN groups of 2,5‐disubstituted piperazines on the pKa and carbamate stability towards hydrolysis are investigated by quantum chemical methods. For the calculations, B3LYP, M11L, and spin‐component‐scaled MP2 (SCS‐MP2) methods are used and coupled with the SMD solvation model. The experimental pKa values of piperazine, 2‐methylpiperazine, and 2,5‐dimethylpiperazine agree well with the calculated values. The present study indicates that substitution of CH3, CH2NH2, and CH2OH groups on the 2‐ and 5‐positions of piperazine has a positive impact on the CO2 absorption capacity by reducing the carbamate stability towards hydrolysis. Furthermore, their higher boiling points, relative to piperazine itself, will lead to a reduction of volatility‐related losses.
Rapid and Cost‐Effective Synthesis of Nanosized Zeolitic Imidazolate Framework‐7 with N,N′‐Dimethylformamide as Solvent and Metal Acetate Salt as Metal Source
Authors: Wang Xiang , Huang Pengcheng , Yu Ping , Yang Lifen , Mao Lanqun 
Published: April 2014

AbstractIn this study, a new method was developed for the rapid and cost‐effective synthesis of nanosized zeolitic imidazolate framework‐7 (ZIF‐7) nanocrystals with a high yield and a low molar ratio of benzimidazole ligand to metal salt (2:1) by using N,N′‐dimethylformamide (DMF) as the solvent and zinc acetate dihydrate (Zn(OAc)2⋅2 H2O) as the metal source. The synthesized ZIF‐7 nanocrystals have a size of approximately 50–80 nm, and tend to aggregate or become intergrown to form irregular nanoparticles of about 200–300 nm in size. The morphology and yield of the ZIF‐7 nanocrystals can be tuned easily by changing the synthetic parameters such as the composition of the solvent and concentrations of reagents. The synthesized ZIF‐7 nanocrystals exhibit good thermal and chemical stability, CO2 capture capability, and fluorescent properties. Remarkably, we find that the synthetic strategy developed here can be extended to the syntheses of other kinds of ZIFs including ZIF‐69 and ZIF‐90. This study offers a new, simple synthetic strategy for the high‐yield preparation of ZIF materials.