bluuebunny/crossref_metadata_2025_split huggingface dataset:
Down‐regulation of G protein‐coupled receptor 137 by RNA interference inhibits cell growth of two hepatoma cell lines
Authors: Shao Xin , Liu Yong , Huang Hai , Zhuang Linyuan , Luo Tianping , Huang Huping , Ge Xinguo 
Published: December 2014

AbstractG protein‐coupled receptors (GPCRs) are important signal transduction mediators and pharmacological therapeutic targets. G protein‐coupled receptor 137 (GPR137) was initially reported as a novel orphan GPCR around 10 years ago. Some orphan GPCRs have been implicated in cancer cell proliferation and migration. The aim of this study is to investigate the role of GPR137 in hepatocellular carcinoma (HCC). GPR137 is widely expressed in several human HCC cell lines, as determined by real‐time PCR. We then applied lentivirus mediated RNA interference (RNAi) to knock down GPR137 expression in two HCC cell lines HepG2 and Bel7404. Depletion of GPR137 remarkably inhibited cell proliferation and colony formation capacity. Knockdown of GPR137 in HepG2 cells led to cell cycle arrest at G0/G1 phase and G2/M phase, and induced cell apoptosis, as determined by flow cytometry analysis, which contributed to cell growth inhibition. Our findings suggested that GPR137 could facilitate HCC cell proliferation and thus promote hepatocarcinogenesis. Cell Biol Int XX (2014) XXXX–XXXX © 2014 International Federation for Cell Biology
Retrofitting of the Heat Exchanger Network with Steam Generation in a Crude Oil Distillation Unit
Authors: Gu Wugen , Chen Xiaozhong , Liu Kai , Zhang Bingjian , Chen Qinglin , Hui Chi‐Wai 
Published: December 2014

AbstractSteam generation through hot streams has an important impact on the utility consumption of a crude oil distillation unit. Retrofitting of the heat exchanger network with steam generation in a crude oil distillation unit is studied with regard to efficient energy usage. The grand composite curve is employed to provide insights into the steam generation problem, and a mixed‐integer linear programming model, presented previously for heat integration through hot discharges/feeds and steam generation, is used to obtain the optimal parameters for steam generation. Three heuristic rules are then proposed to determine suitable hot streams for steam generation. Finally, the heat exchanger network is modified based on pinch technology. After the retrofit, the hot and cold utility decrease.
The Formation of High‐Order Polybromides in a Room‐Temperature Ionic Liquid: From Monoanions ([Br5]− to [Br11]−) to the Isolation of [PC16H36]2[Br24] as Determined by van der Waals Bonding Radii
Authors: Easton Max E. , Ward Antony J. , Hudson Toby , Turner Peter , Masters Anthony F. , Maschmeyer Thomas 
Published: December 2014

AbstractAn unprecedented diversity of high‐order bromine catenates (anionic polybromides) was generated in a tetraalkylphosphonium‐based room temperature ionic liquid system. Raman spectroscopy was used to identify polybromide monoanions ranging from [Br5]− to [Br11]− in the bulk solution, while single‐crystal X‐ray diffraction identified extended networks of linked [Br11]− units, forming a previously unknown polymeric [Br24]2− dianion. This represents the largest polybromide species identified to date. In combination with recent work, this suggests that other, higher order molecular polybromide ions might be isolated.
When Self‐Assembly Fails: Stepwise Metal‐Directed Synthesis of [2]Catenanes
Authors: López‐Vidal Eva M. , García Marcos D. , Peinador Carlos , Quintela José M. 
Published: December 2014

AbstractOn the attempted synthesis of a series of homo‐ and heterotrimetallic [2]catenanes by the self‐assembly of a 2‐(pyridin‐4‐ylmethyl)‐2,7‐diazapyrenium ligand, (ethylenediamine)palladium(II) or platinum(II) nitrate, and a dioxoaryl bis(N‐monoalkyl‐4,4′‐bipyridinium) salt as building blocks, both the one‐pot direct self‐assembly of the components and the so called “magic ring” approach fail to produce the expected trinuclear [2]catenanes under thermodynamically driven conditions. However, one of the target supramolecules is obtained by following a stepwise protocol, consisting of the threading of a dinuclear PtII metallacycle and the dioxoaryl bis(N‐monoalkyl‐4,4′‐bipyridinium) axle, followed by kinetically controlled PtII‐directed cyclization of the corresponding pseudorotaxane.
Structural and Kinetic Dissection of the endo‐α‐1,2‐Mannanase Activity of Bacterial GH99 Glycoside Hydrolases from Bacteroides spp.
Authors: Hakki Zalihe , Thompson Andrew J. , Bellmaine Stephanie , Speciale Gaetano , Davies Gideon J. , Williams Spencer J. 
Published: December 2014

AbstractGlycoside hydrolase family 99 (GH99) was created to categorize sequence‐related glycosidases possessing endo‐α‐mannosidase activity: the cleavage of mannosidic linkages within eukaryotic N‐glycan precursors (Glc1–3Man9GlcNAc2), releasing mono‐, di‐ and triglucosylated‐mannose (Glc1–3‐1,3‐Man). GH99 family members have recently been implicated in the ability of Bacteroides spp., present within the gut microbiota, to metabolize fungal cell wall α‐mannans, releasing α‐1,3‐mannobiose by hydrolysing αMan‐1,3‐αMan→1,2‐αMan‐1,2‐αMan sequences within branches off the main α‐1,6‐mannan backbone. We report the development of a series of substrates and inhibitors, which we use to kinetically and structurally characterise this novel endo‐α‐1,2‐mannanase activity of bacterial GH99 enzymes from Bacteroides thetaiotaomicron and xylanisolvens. These data reveal an approximate 5 kJ mol−1 preference for mannose‐configured substrates in the −2 subsite (relative to glucose), which inspired the development of a new inhibitor, α‐mannopyranosyl‐1,3‐isofagomine (ManIFG), the most potent (bacterial) GH99 inhibitor reported to date. X‐ray structures of ManIFG or a substrate in complex with wild‐type or inactive mutants, respectively, of B. xylanisolvens GH99 reveal the structural basis for binding to D‐mannose‐ rather than D‐glucose‐configured substrates.
Mesoporous Bubble‐like Manganese Silicate as a Versatile Platform for Design and Synthesis of Nanostructured Catalysts
Authors: Zhan Guowu , Yec Christopher C. , Zeng Hua Chun 
Published: December 2014

AbstractManganese silicate in bubble‐like morphology was used as a versatile platform to prepare a new class of yolk–shell hybrids. The mesoporosity of the shell was generated from the interbubble space and the bubble structure of manganese silica was used to hold and support nanoparticles (e.g., Au, Ag, Pt, Co, Ni, Au–Pd alloy, MoO2, Fe3O4, carbon nanotubes and their combinations). We also used heterogeneous catalysis reactions to demonstrate the workability of these catalysts in both liquid and gas phases.
Investigation of Alkyne Regioselectivity in the Ni‐Catalyzed Benzannulation of Cyclobutenones
Authors: Stalling Timo , Harker Wesley R. R. , Auvinet Anne‐Laure , Cornel Erik J. , Harrity Joseph P. A. 
Published: December 2014

AbstractA Ni‐catalyzed benzannulation reaction of cyclobutenones and alkynes provides a rapid synthesis of heavily substituted phenols. The regioselectivity of this reaction can be modulated by variation of substituents on the alkyne. Though the incorporation of Lewis basic donors provides modest selectivities, the use of aryl substituents can provide high levels of regiocontrol. Finally, alkynylboronates derived from alkyl‐substituted acetylenes provide both high yields and regioselectivities. This study suggests that alkynes bearing one sp2‐ and one sp3‐based substituent can undergo benzannulation with high levels of regiocontrol whereby the sp3‐based group is incorporated ortho‐to the phenolic OH.
Macrocycle Embrace: Encapsulation of Fluoroarenes by m‐Phenylene Ethynylene Host
Authors: Popov Ilya , Chen Teng‐Hao , Belyakov Sergey , Daugulis Olafs , Wheeler Steven E. , Miljanić Ognjen Š. 
Published: December 2014

AbstractWe report structural characterization of a new member of m‐phenylene ethynylene ring family. This shape‐persistent macrocycle also co‐crystallizes with hexafluoro‐, 1,2,4,5‐tetrafluoro‐, 1,3,5‐trifluoro, and 1,4‐difluorobenzene. The four complexes are almost isostructural, and all show the fluoroarene included into the central cavity of the macrocycle. Characterized by multiple short CH⋅⋅⋅FC contacts, these inclusion complexes further dimerize in the solid state into a 2+2 assembly, in which the two macrocycles embrace each other by their large hydrophobic groups that are rotated by 60° relative to one another.
Enhancing Effects of Salt Formation on Catalytic Activity and Enantioselectivity for Asymmetric Hydrogenation of Isoquinolinium Salts by Dinuclear Halide‐Bridged Iridium Complexes Bearing Chiral Diphosphine Ligands
Authors: Kita Yusuke , Yamaji Kenta , Higashida Kosuke , Sathaiah Kandula , Iimuro Atuhiro , Mashima Kazushi 
Published: December 2014

AbstractInvited for the cover of this issue is the group of Kazushi Mashima at Osaka University. The image depicts a novel six‐membered outer sphere transition state—the substrate and product are represented by locomotives with a six‐membered rail, and chiral induction by a signal. Read the full text of the article at 10.1002/chem.201405408.
Platinum trans‐Bis(borirene) Complexes Displaying Coplanarity and Communication Across a Platinum Metal Center
Authors: Braunschweig Holger , Damme Alexander , Dewhurst Rian D. , Kelch Hauke , Macha Bret B. , Radacki Krzysztof , Vargas Alfredo , Ye Qing 
Published: December 2014

AbstractInvited for the cover of this issue is the group of Holger Braunschweig at the Julius‐Maximilians‐Universität Würzburg. The image depicts a “fight” for coplanarity in platinum­ trans‐bis(borirene) complexes. Read the full text of the article at 10.1002/chem.201405803.
Novel Magnetic Cross‐Linked Lipase Aggregates for Improving the Resolution of (R, S)‐2‐octanol
Authors: Liu Ying , Guo Chen , Liu Chun‐Zhao 
Published: December 2014

AbstractNovel magnetic cross‐linked lipase aggregates were fabricated by immobilizing the cross‐linked lipase aggregates onto magnetic particles with a high number of ‐NH2 terminal groups using p‐benzoquinone as the cross‐linking agent. At the optimal fabrication conditions, 100% of immobilization efficiency and 139% of activity recovery of the magnetic cross‐linked lipase aggregates were achieved. The magnetic cross‐linked lipase aggregates were able to efficiently resolve (R, S)‐2‐octanol, and retained 100% activity and 100% enantioselectivity after 10 cycles of reuse, whereas the cross‐linked lipase aggregates only retained about 50% activity and 70% enantioselectivity due to insufficient cross‐linking. These results provide a great potential for industrial applications of the magnetic cross‐linked lipase aggregates. Chirality 27:199–204, 2015. © 2014 Wiley Periodicals, Inc.
Die Selivanov‐Probe auf Fructose
Authors: Shuklov Ivan A. , Boeck Gisela 
Published: December 2014

AbstractAuch wenn die Selivanov‐Probe heute in der reinen präparativen Chemie auf dem Gebiet der Kohlenhydrate eine untergeordnete Rolle spielt, ist sie in der Analytik der Biochemie und der Lebensmittelchemie bis heute als Nachweis für Fructose von Bedeutung. In diesem Beitrag wurde der Werdegang von Fédor Fédorovic̆ Selivanov, des aus einer Adelsfamilie stammenden, mit volkstümlerischen Gedanken konfrontierten, in Russland, in der Schweiz und in Deutschland ausgebildeten Chemikers dargestellt. Auf seinem Lebensweg begegnete er in verschiedenen Ländern vielen Chemikern, die in weit größerem Ausmaß als Selivanov selbst Spuren hinterlassen haben. Seine Publikationen zeugen von einem regen Wissensaustausch zwischen den Chemie‐ bzw. Agrochemiezentren in Russland und Deutschland. Zu Selivanovs wesentlichen Leistungen zählen neben dem Fructose‐Nachweis wichtige Arbeiten auf dem Gebiet der Halogenstickstoffe, besonders auch die erste Synthese von N‐Bromsuccinimid. Als zeitweiliger Vorgesetzter von Arbuzov ermöglichte er ihm, experimentelle Arbeiten durchzuführen, von denen die sogenannte Michaelis‐Arbuzov‐Reaktion in die Geschichte eingegangen ist.
Profragrances – Riechstoffvorstufen
Authors: Herrmann Andreas 
Published: December 2014

AbstractProfragrances und Proparfüme setzen Riechstoffe mittels einer kovalenten Bindungsspaltung aus nichtflüchtigen Vorstufen frei, um die Dauer der Duftwirkung in Anwendungen der funktionellen Parfümerie zu verlängern. Freisetzungssysteme, die auf Riechstoffvorläufern basieren, benötigen Reaktionsbedingungen, die mit den milden Umgebungsbedingungen in unserem Alltagsleben vereinbar sind. Riechstoffvorstufen werden typischerweise durch enzymatische Umwandlungen, Hydrolysen (z. B. ausgelöst durch einen pH‐Wechsel), Oxidationen mit Luftsauerstoff, milde Temperaturunterschiede oder durch Tageslicht gespalten. Erfolgreiche Riechstoffvorläufer sind preisgünstig, lagerungsstabil und setzen den entsprechenden Riechstoff effizient nach ihrer Ablagerung auf der Zieloberfläche frei. Dies sind Anforderungen, die in der Praxis nicht immer leicht zu erfüllen sind.
Ultraschnelle Dynamik von Strukturen und Schwingungen
Authors: Elsaesser Thomas 
Published: December 2014

AbstractAufgrund der begrenzten Bindungsstärke von Wasserstoffbrücken unterliegen wässrige Systeme ultraschnellen strukturellen Fluktuationen im Zeitbereich zwischen 10–14 und 10–11 s. Schwingungsanregungen von Wasserstoffbrücken zerfallen ebenfalls in diesem Zeitbereich. Die mehrdimensionale Ultrakurzzeit‐Infrarotspektroskopie erlaubt eine zeitaufgelöste Beobachtung dieser elementaren Dynamik in Wasser, hydratisierten DNA‐Oligomeren und Phospholipiden. Neben Kopplungen zwischen Schwingungsfreiheitsgraden des hydratisierten Systems lässt sich die Wasserdynamik an Grenzflächen und im Volumen direkt aufzeichnen. Strukturelle Fluktuationen im Volumen von H2O treten im Zeitbereich zwischen 5×10–14 und 10–12 s auf, Wasserstoffbrücken werden im Takt von 10–12 s gebrochen und neu geformt. An den Grenzflächen zu DNA und Phospholipiden existieren Hydratisierungsgeometrien, die bei geringen Fluktuationen länger als 10–11 s aufrecht erhalten werden. Ein langlebiges ‘Gedächtnis’ des Wassers existiert jedoch nicht.
Ein neuer Molekülbaukasten
Authors: Groß Michael 
Published: December 2014

AbstractChemie wäre viel einfacher, wenn man Moleküle einfach zusammenstöpseln könnte wie Legosteine – ohne gefährliche Reagenzien und Nebenprodukte. Durch cleveres Design der Bausteine haben Chemiker jetzt eine neue Gruppe von vielfältig variierbaren Synthesen entwickelt, die diesem Ideal der Klick‐Chemie [4] entsprechen und den Zugang zu vielfältigen, auch pharmakologisch interessanten Produkten eröffnen.
Chemical‐Looping Reforming of Methane Using Iron Based Oxygen Carrier Modified with Low Content Nickel
Authors: Wei Guoqiang , He Fang , Huang Zhen , Zhao Kun , Zheng Anqing , Li Haibin 
Published: December 2014

AbstractFe2O3/Al2O3 and Fe2O3/Al2O3 modified by low content of Ni (below 2% in weight) oxygen carriers were prepared by mechanical mixing and impregnation method. The synthesized oxygen carriers were characterized by means of X‐ray diffraction (XRD), X‐ray fluorescence (XRF), scanning electron microscopy (SEM), BET‐surface area and temperature programmed reduction (TPR). Besides, redox cyclic reactivity and the performance of chemical looping reforming of methane of the oxygen carriers were studied in a thermal gravimetrical analysis (TGA) and fixed bed at 850°C. It was observed that the redox reactivity of the oxygen carriers is improved by Ni addition because synergic effect may occur between NiO and Fe2O3/Al2O3 to form NiFe2O4 and NiAl2O4 spinel phases. However, the improvement was not apparent as Ni addition reached 1 wt% or more because more nickel loaded resulted in methane decomposition into H2 and carbon leading to carbon deposition. The SEM and BET analysis showed that NiFe2O4 and NiAl2O4 particles dispersed into the pores of the Fe2O3/Al2O3 particles in the course of preparation. In addition, the resistance to sintering of the modified samples increased with the Ni addition increasing. The results of successive redox cycles showed that the Ni modified Fe2O3/Al2O3 oxygen carriers have good regenerability. With integration of reactivity and carbon deposition, the content 1.04 wt% of nickel doping was an optimal amount in the three modified samples.
Continuous Dehydrogenation of n‐Pentanol over a Cr Modified Cu/γ‐Al2O3‐La2O3 Catalyst
Authors: Liu Chen , Wang Yalong , Chu Hailong , Qiu Mande , Niu Libo , Bai Guoyi 
Published: December 2014

AbstractThe oxidant‐free dehydrogenation of n‐pentanol over copper based catalysts was investigated in this paper. The effect of metal modification on the activity and stability of the copper catalyst supported on γ‐Al2O3 and La2O3 (Cu/γ‐Al2O3‐La2O3) was clarified and a Cr modified Cu/Al2O3‐La2O3 (Cu‐Cr/γ‐Al2O3‐La2O3) showed the best catalytic performance. The conversion of n‐pentanol was 70.0% and the selectivity for n‐pentanal increased to 97.1% over Cu‐Cr/γ‐Al2O3‐La2O3. X‐ray diffraction and temperature programmed reduction of H2 indicated that the addition of Cr favors the formation and reduction of the copper oxide, and the dispersion of the active Cu0 species, accounting for the good activity and stability of this catalyst. Furthermore, the lower amount of acidic sites in Cu‐Cr/γ‐Al2O3‐La2O3 is suggested to suppress the dehydration in oxidant‐free dehydrogenation of n‐pentanol, accounting for the higher selectivity for n‐pentanal.
Site‐specific Analysis of Amyloid Assemblies by Using Scanning Tunneling Microscopy
Authors: Yu Yue , Yang Yanlian , Wang Chen 
Published: December 2014

AbstractThe assembly of amyloid peptides into highly organized fibrils is one of the major characteristics of many degenerative diseases such as Alzheimer's disease and type II diabetes. Assembly structures of amyloid peptides at liquid‐solid interface can be visualized by scanning tunneling microscopy (STM) with site‐specific resolution. The STM analysis can provide valuable information on the folding mechanism of amyloid peptides based on the correlation of surface assembly structures and fibrillation behaviors. Cases on mutational analysis of amyloid peptides by STM are also reviewed which illustrate the capacities of STM studies on amyloid assemblies.
A Fluorescent Chemosensor for Dihydrogen Phosphate Ion Based on 2‐[2‐Hydroxy‐4‐(diethylamino) phenyl]‐1H‐imidazo[4,5‐b]phenazine‐Fe3+ Ensemble
Authors: Wei Taibao , Wu Guiyuan , Shi Bingbing , Lin Qi , Yao Hong , Zhang Youming 
Published: December 2014

AbstractA long wavelength emission fluorescent (612 nm) chemosensor with high selectivity for H2PO4− ions was designed and synthesized according to the excited state intramolecular proton transfer (ESIPT). The sensor can exist in two tautomeric forms ('keto' and 'enol') in the presence of Fe3+ ion, Fe3+ may bind with the 'keto' form of the sensor. Furthermore, the in situ generated GY‐Fe3+ ensemble could recover the quenched fluorescence upon the addition of H2PO4− anion resulting in an off‐on‐type sensing with a detection limit of micromolar range in the same medium, and other anions, including F−, Cl−, Br−, I−, AcO−, HSO4−, ClO4− and CN− had nearly no influence on the probing behavior. The test strips based on 2‐[2‐hydroxy‐4‐(diethylamino) phenyl]‐1H‐imidazo[4,5‐b]phenazine and Fe3+ metal complex (GY‐Fe3+) were fabricated, which could act as convenient and efficient H2PO4− test kits.
Direct Myocardial Ischemia Imaging: a New Cardiovascular Nuclear Imaging Paradigm
Authors: Jain Diwakar , He Zuo‐Xiang , Lele Vikram , Aronow Wilbert S. 
Published: December 2014

AbstractMyocardial perfusion imaging (MPI), using radiotracers, has been in routine clinical use for over 40 years. This modality is used for the detection of coronary artery disease (CAD), risk stratification, optimizing therapy, and follow‐up of patients with CAD. Molecular cardiovascular imaging using targeted radiotracers provides a unique opportunity for imaging biochemical and metabolic processes, and cell membrane transporter and receptor functions at a cellular and molecular level in experimental animal models as well as in humans. Cardiac imaging using radiolabeled free fatty acid analogues and glucose analogues enable us to image myocardial ischemia directly as an alternative to stress‐rest MPI. Direct ischemia imaging techniques can avoid and overcome some of the limitations of standard stress‐rest MPI. This article describes recent studies using 18F‐fluorodeoxyglucose (18FDG) for myocardial ischemia imaging.
Promiscuity and the Conformational Rearrangement of Drug‐Like Molecules: Insight from the Protein Data Bank
Authors: He Michael W. , Lee Patrick S. , Sweeney Zachary K. 
Published: December 2014

AbstractSelectivity is a central aspect of lead optimization in the drug discovery process. Medicinal chemists often try to decrease molecular flexibility to improve selectivity, given the common belief that the two are interdependent. To investigate the relationship between polypharmacology and conformational flexibility, we mined the Protein Data Bank and constructed a dataset of pharmaceutically relevant ligands that crystallized in more than one protein target while binding to each co‐crystallized receptor with similar in vitro affinities. After analyzing the molecular conformations of these 100 ligands, we found that 59 ligands bound to different protein targets without significantly changing conformation, suggesting that there is no distinct correlation between conformational flexibility and polypharmacology within our dataset. Ligands crystallized in similar proteins and highly ligand‐efficient compounds with five or fewer rotatable bonds were less likely to adjust conformation when binding.