bluuebunny/crossref_metadata_2025_split huggingface dataset:
[Ge2]4− Dumbbells with Very Short Ge−Ge Distances in the Zintl Phase Li3NaGe2: A Solid‐State Equivalent to Molecular O2
Authors: Scherf Lavinia M. , Karttunen Antti J. , Pecher Oliver , Magusin Pieter C. M. M. , Grey Clare P. , Fässler Thomas F. 
Published: December 2015

AbstractThe novel ternary Zintl phase Li3NaGe2 comprises alkali‐metal cations and [Ge2]4− dumbbells. The diatomic [Ge2]4− unit is characterized by the shortest Ge−Ge distance (2.390(1) Å) ever observed in a Zintl phase and thus represents the first Ge=Ge double bond under such conditions, as also suggested by the (8−N) rule. Raman measurements support these findings. The multiple‐bond character is confirmed by electronic‐structure calculations, and an upfield 6Li NMR shift of −10.0 ppm, which was assigned to the Li cations surrounded by the π systems of three Ge dumbbells, further underlines this interpretation. For the unperturbed, ligand‐free dumbbell in Li3NaGe2, the π‐ bonding py and pz orbitals are degenerate as in molecular oxygen, which has singly occupied orbitals. The partially filled π‐type bands of the neat solid Li3NaGe2 cross the Fermi level, resulting in metallic properties. Li3NaGe2 was synthesized from the elements as well as from binary reactants and subsequently characterized crystallographically.
A Copper‐Based Metal–Organic Framework Acts as a Bifunctional Catalyst for the Homocoupling of Arylboronic Acids and Epoxidation of Olefins
Authors: Parshamoni Srinivasulu , Telangae Jyothi , Sanda Suresh , Konar Sanjit 
Published: December 2015

AbstractA copper(I)‐based metal–organic framework ({[Cu2Br2(pypz)]n⋅nH2O} (Cu—Br–MOF) [pypz=bis[3,5‐dimethyl‐4‐(4’‐pyridyl)pyrazol‐1‐yl] methane] has been synthesized by using an elongated and flexible bridging ligand. The structure analysis reveals that each pypz ligand acts as a tritopic ligand connected to two Cu2Br2 dimeric units, forming a one‐dimensional zig–zag chain, and these chains further connected by a Cu2Br2 unit, give a two‐dimensional framework on the bc‐plane. In the Cu2Br2 dimeric unit, the copper ions are four coordinated, thereby possessing a tetrahedral geometry; this proves to be an excellent heterogeneous catalyst for the aerobic homocoupling of arylboronic acids under mild reaction conditions. This method requires only 3 mol % of catalyst and it does not require any base or oxidant—compared to other conventional (Cu, Pd, Fe, and Au) catalysts—for the transformation of arylboronic acids in very good yields (98 %). The shape and size selectivity of the catalyst in the homocoupling was investigated. The use of the catalyst was further extended to the epoxidation of olefins. Moreover, the catalyst can be easily separated by simple filtration and reused efficiently up to 5 cycles without major loss of reactivity.
Tetranuclear Heterometallic {Zn2Eu2} Complexes With 1‐Naphthoate Anions: Synthesis, Structure and Photoluminescence Properties
Authors: Goldberg Anna , Kiskin Mikhail , Shalygina Olga , Kozyukhin Sergey , Dobrokhotova Zhanna , Nikolaevskii Stanislav , Sidorov Alexey , Sokolov Sergey , Timoshenko Victor , Goloveshkin Alexander , Eremenko Igor 
Published: December 2015

AbstractA series of new tetranuclear heterometallic ZnII‐EuIII complexes have been synthesized, that is, (bpy)2Zn2Eu2(naph)10 (1), (bpy)2Zn2Eu2(naph)8(NO3)2 (2), and (phen)2Zn2Eu2(naph)8(NO3)2 (3), and other ones, where naph− is the 1‐naphthoate anion, bpy=2,2′‐bipyridyl, and phen=1,10‐phenanthroline. The solid‐phase complexes consist of large supramolecular ensembles due to stacking interactions between the aromatic ligands. Photoluminescence (PL) measurements were carried out to study PL spectra, lifetimes and quantum yields (QY) of the synthesized complexes at different temperatures. The external QY for the solid phases of complexes under UV excitation was found to exceed 20 %. It has been shown that partial replacement of naphthoate ligands in the coordination environment of Eu3+ by NO3− anions influences the PL properties. To investigate the behavior of these complexes in solvent, we dissolved complex 3 in MeCN, put it on a transparent glass as a substrate, and studied the PL properties at room temperature.
Sicherer Einsatz von Glasfaserbewehrung im Bauwesen
Authors: Knab Franz , Weber André , Schweinfurth Jörg 
Published: December 2015

AbstractBewehrung aus Glasfaserverbundwerkstoffen wird seit über 20 Jahren bei besonderen Anforderungen an Bewehrungseigenschaften erfolgreich eingesetzt. Mit der erstmaligen Zulassung eines Glasfaserbewehrungsstabs in Deutschland 2008 wurde die Grundlage für die breitere Nutzung dieser Technologie geschaffen.Nachfolgend werden Unterschiede des Materialverhaltens von Glasfaserbewehrung gegenüber Stahl aufgezeigt und wichtige Grundlagen zur Bemessung vorgestellt. Praktische Hinweise zur Vergleichbarkeit von Glasfaserbewehrungen und zum Thema Zustimmung im Einzelfall sowie ein Ausblick auf die Regelungen zu Glasfaserbewehrung in der nächsten Generation des EC2 sollen den planenden Ingenieur bei der sicheren Anwendung unterstützen. Beispiele ausgeführter Projekte geben einen Überblick auf die verschiedenen Einsatzgebiete dieser Spezialbewehrungsart.Safe application of glass fibre rebar in civil engineering. Hints and examples for practiceIn cases where reinforcement with special requirements is needed, glass fibre reinforced polymer bars have successfully been used since more than 20 years. The first approval by the German building authorities (DIBt) has been issued in 2008 giving way for broad application of this technology.This article focuses on differences in the material behaviour of mild steel and glass fibre rebar and offers basic knowledge for the design of glass fibre rebar. Additional information on comparison of different materials as well as for single use permissions (ZiE) is given. This knowledge combined with a glance on the future regulations on glass fibre rebar in the next EC2 shall enable structural engineers to perform safe calculations and a proper application of glass fibre rebar.Examples of carried out projects give an overview of the broad field of applications.
Specific interactions of alcohols and non‐alcohols with a biologically active boronic acid derivative: a spectroscopic study
Authors: Geethanjali H. S. , Melavanki R. M. , Nagaraja D. , Patil N. R. , Thipperudrappa J. , Kusanur R. A. 
Published: December 2015

AbstractThe photophysical properties of 4‐fluoro‐2‐methoxyphenyl boronic acid (4FMPBA) are characterized using absorption and fluorescence techniques in series of non‐alcohols and alcohols. The results are analyzed using different solvent polarity functions and Kamlet and Catalan's multiple regression approaches. The excited state dipole moment and change in dipole moment are calculated using both the solvatochromic shift method and Reichardt's microscopic solvent polarity parameter
. The ground state dipole moment is evaluated using quantum chemical calculations. It is found that general solute–solvent and hydrogen bond interactions are operative in this system. A red shift of ~ 9 nm in the emission spectra is observed with an increase in the solvent polarity, which depicts π→π* transitions, as well as the possibility of an intramolecular charge transfer (ICT) character in the emitting singlet state of 4FMPBA. The relative quantum yield, radiative and non‐radiative decay constants are calculated in alkanes and alcohols using the single point method. It is found that the quantum yield of the molecule varies from 16.81% to 50.79% with the change in solvent polarity, indicating the dependence of fluorescence on the solvent environment. Copyright © 2015 John Wiley & Sons, Ltd.
High yield of recombinant human Apolipoprotein A‐I expressed in Pichia pastoris by using mixed‐mode chromatography
Authors: Narasimhan Janakiraman Vignesh , Noubhani Abdelmajid , Venkataraman Krishnan , Vijayalakshmi Mookambeswaran , Santarelli Xavier 
Published: December 2015

AbstractA vast majority of the cardioprotective properties exhibited by High‐Density Lipoprotein (HDL) is mediated by its major protein component Apolipoprotein A‐I (ApoA1). In order to develop a simplified bioprocess for producing recombinant human Apolipoprotein A‐I (rhApoA1) in its near‐native form, rhApoA1was expressed without the use of an affinity tag in view of its potential therapeutic applications. Expressed in Pichia pastoris at expression levels of 58.2 mg ApoA1 per litre of culture in a reproducible manner, the target protein was purified by mixed‐mode chromatography using Capto™ MMC ligand with a purity and recovery of 84% and 68%, respectively. ApoA1 purification was scaled up to Mixed‐mode Expanded Bed Adsorption chromatography to establish an 'on‐line' process for the efficient capture of rhApoA1 directly from the P. pastoris expression broth. A polishing step using anion exchange chromatography enabled the recovery of ApoA1 up to 96% purity. Purified ApoA1 was identified and verified by RPLC‐ESI‐Q‐TOF mass spectrometry. This two‐step process would reduce processing times and therefore costs in comparison to the twelve‐step procedure currently used for recovering rhApoA1 from P. pastoris
Freestanding stacked mesh‐like hydrogel sheets enable the creation of complex macroscale cellular scaffolds
Authors: Son Jaejung , Bae Chae Yun , Park Je‐Kyun 
Published: December 2015

AbstractHydrogel‐based bottom‐up tissue engineering depends on assembly of cell‐laden modules for complex three‐dimensional tissue reconstruction. Though sheet‐like hydrogel modules enable rapid and controllable assembly, they have limitations in generating spatial microenvironments and mass transport. Here, we describe a simple method for forming large‐scale cell‐hydrogel assemblies via stacking cell‐embedded mesh‐like hydrogel sheets to create complex macroscale cellular scaffolds. Freestanding stacked hydrogel sheets were fabricated for long‐term cell culturing applications using a facile stacking process where the micropatterned hydrogel sheets (8.0 mm × 8.7 mm) were aligned using a polydimethylsiloxane drainage well. The stacked hydrogel sheets were precisely aligned so that the openings could facilitate mass transport through the stacked sheets. Despite the relatively large height of the stacked structure (400–700 μm), which is larger than the diffusion limit thickness of 150–200 μm, the freestanding cell‐ydrogel assemblies maintained cell viability and exhibited enhanced cellular function compared with single hydrogel sheets. Furthermore, a three‐dimensional co‐culture system was constructed simply by stacking different cell‐containing hydrogel sheets. These results show that stacked hydrogel sheets have significant potential as a macroscale cell‐culture and assay platform with complex microenvironments for biologically relevant in vitro tissue‐level drug assays and physiological studies.
PLK2 phosphorylates and inhibits enriched TAp73 in human osteosarcoma cells
Authors: Hu Zheng Bo , Liao Xiao Hong , Xu Zun Ying , Yang Xiao , Dong Chao , Jin An Min , Lu Hai 
Published: December 2015

AbstractTAp73, a member of the p53 tumor suppressor family, can substitute for p53 function, especially in p53‐null and p53‐mutant cells. However, TAp73 enrichment and phosphorylation change its transcriptional activity. Previously, we found that the antitumor function of TAp73 was reactivated by dephosphorylation. Polo‐like kinase 2 (PLK2) plays an important role in bone development. Using a biological information database and phosphorylation prediction software, we hypothesized that PLK2 phosphorylates TAp73 and inhibits TAp73 function in osteosarcomas. Actually,we determined that PLK2 physically binds to and phosphorylates TAp73 when TAp73 protein abundance is up‐regulated by cisplatin. PLK2‐phosphorylated TAp73 at residue Ser48 within the TA domain; phosphorylation of TAp73 was abolished by mutating this residue. Moreover, PLK2 inhibition combined with cisplatin treatment in osteosarcoma Saos2 cells up‐regulated p21 and puma mRNA expression to a greater extent than cisplatin treatment alone. Inhibiting PLK2 in TAp73‐enriched Saos2 cells resulted in inhibited cell proliferation, increased apoptosis, G1 phase arrest, and decreased cell invasion. However, these changes did not occur in TAp73 knockdown Saos2 cells. In conclusion, these findings reveal a novel PLK2 function in the phosphorylation of TAp73, which prevents TAp73 activity in osteosarcoma cells. Thereby, this research provides an insight into the clinical treatment of malignant tumors overexpressing TAp73.
Simultaneous Liquefaction and Hydrodeoxygenation of Lignocellulosic Biomass over NiMo/Al2O3, Pd/Al2O3, and Zeolite Y Catalysts in Hydrogen Donor Solvents
Authors: Grilc Miha , Likozar Blaž , Levec Janez 
Published: December 2015

AbstractThe one‐step solvolysis and hydro‐treatment of oak, fir and beech sawdust was studied in a slurry reactor using tetralin, phenol and glycerol as solvents and representative heterogeneous catalysts used in the petrochemical industry for hydrogenolysis (the sulfide form of NiMo/Al2O3), hydrogenation (Pd/Al2O3) or fluid catalytic cracking (zeolite Y). Deoxyliquefaction products of cellulose, hemicellulose and lignin were characterised in terms of solvent fractionation, FTIR and diffuse reflectance infrared Fourier transform spectroscopy, elemental analysis and an innovative method for particle size distribution and mean grain size determination by SEM image processing. A new lumped kinetic model was developed according to the reaction mechanisms, which contain wood de‐polymerisation, decarbonylation, decarboxylation and demethanation, tar phase hydrodeoxygenation by molecular and in situ generated hydrogen, as well as charring inhibition by free‐radical stabilisation hydrogen transfer.
Selective Synthesis of Trimethylamine by Catalytic N‐Methylation of Ammonia and Ammonium Chloride by utilizing Carbon Dioxide and Molecular Hydrogen
Authors: Beydoun Kassem , Thenert Katharina , Streng Emilia S. , Brosinski Sandra , Leitner Walter , Klankermayer Jürgen 
Published: December 2015

AbstractThe synthesis of trimethylamine (TMA) through a multicomponent combination of ammonia with carbon dioxide and molecular hydrogen by using a homogeneous ruthenium catalyst was explored. The use of [Ru(triphos)(tmm)] [triphos: 1,1,1‐tris(diphenylphosphinomethyl)ethane, tmm: trimethylene methane] together with aluminum trifluoromethanesulfonate as a co‐catalyst resulted in high ammonia conversion and excellent selectivity for TMA in organic solvents. Aqueous solutions of ammonium chloride were methylated almost quantitatively to the corresponding hydrochloride salt (i.e., TMA⋅HCl) in a biphasic solvent system by using the same Ru complex without the need for any co‐catalyst.
A Computational and Experimental Study of Thieno[3,4‐b]thiophene as a Proaromatic π‐Bridge in Dye‐Sensitized Solar Cells
Authors: Brogdon Phillip , Giordano Fabrizio , Puneky George A. , Dass Amala , Zakeeruddin Shaik M. , Nazeeruddin Mohammad Khaja , Grätzel Michael , Tschumper Gregory S. , Delcamp Jared H. 
Published: December 2015

AbstractFour D‐π‐A dyes (D=donor, A=accpetor) based on a 3,4‐thienothiophene π‐bridge were synthesized for use in dye‐sensitized solar cells (DSCs). The proaromatic building block 3,4‐thienothiophene is incorporated to stabilize dye excited‐state oxidation potentials. This lowering of the excited‐state energy levels allows for deeper absorption into the NIR region with relatively low molecular weight dyes. The influence of proaromatic functionality is probed through a computational analysis of optimized bond lengths and nucleus independent chemical shifts (NICS) for both the ground‐ and excited‐ states. To avoid a necessary lowering of the TiO2 semiconductor conduction band (CB) to promote efficient dye–TiO2 electron injection, strong donor functionalities based on triaryl‐ and diarylamines are employed in the dye designs to raise both the ground‐ and excited‐state oxidation potentials of the dyes. Solubility, aggregation, and TiO2 surface protection are addressed by examining an ethylhexyl alkyl chain in comparison to a simple ethyl chain on the 3,4‐thienothiophene bridge. Power conversion efficiencies of up to 7.8 % are observed.
Limiting the Number of Potential Binding Modes by Introducing Symmetry into Ligands: Structure‐Based Design of Inhibitors for Trypsin‐Like Serine Proteases
Authors: Furtmann Norbert , Häußler Daniela , Scheidt Tamara , Stirnberg Marit , Steinmetzer Torsten , Bajorath Jürgen , Gütschow Michael 
Published: December 2015

AbstractIn the absence of X‐ray data, the exploration of compound binding modes continues to be a challenging task. For structure‐based design, specific features of active sites in different targets play a major role in rationalizing ligand binding characteristics. For example, dibasic compounds have been reported as potent inhibitors of various trypsin‐like serine proteases, the active sites of which contain several binding pockets that can be targeted by cationic moieties. This results in several possible orientations within the active site, complicating the binding mode prediction of such compounds by docking tools. Therefore, we introduced symmetry in bi‐ and tribasic compounds to reduce conformational space in docking calculations and to simplify binding mode selection by limiting the number of possible pocket occupations. Asymmetric bisbenzamidines were used as starting points for a multistage and structure‐guided optimization. A series of 24 final compounds with either two or three benzamidine substructures was ultimately synthesized and evaluated as inhibitors of five serine proteases, leading to potent symmetric inhibitors for the pharmaceutical drug targets matriptase, matriptase‐2, thrombin and factor Xa. This study underlines the relevance of ligand symmetry for chemical biology.
Atomic‐Level Quality Assessment of Enzymes Encapsulated in Bioinspired Silica
Authors: Martelli Tommaso , Ravera Enrico , Louka Alexandra , Cerofolini Linda , Hafner Manuel , Fragai Marco , Becker Christian F. W. , Luchinat Claudio 
Published: December 2015

AbstractAmong protein immobilization strategies, encapsulation in bioinspired silica is increasingly popular. Encapsulation offers high yields and the solid support is created through a protein‐catalyzed polycondensation reaction that occurs under mild conditions. An integrated strategy is reported for the characterization of both the protein and bioinspired silica scaffold generated by the encapsulation of enzymes with an external silica‐forming promoter or with the promoter expressed as a fusion to the enzyme. This strategy is applied to the catalytic domain of matrix metalloproteinase 12. Analysis reveals that the structure of the protein encapsulated by either method is not significantly altered with respect to the native form. The structural features of silica obtained by either strategy are also similar, but differ from those obtained by other approaches. In case of the covalently linked R5–enzyme construct, immobilization yields are higher. Encapsulation through a fusion protein, therefore, appears to be the method of choice.
Direct Assembly of Mesoporous Silica Functionalized with Polypeptides for Efficient Dye Adsorption
Authors: Lu Yi‐Syuan , Bastakoti Bishnu Prasad , Pramanik Malay , Malgras Victor , Yamauchi Yusuke , Kuo Shiao‐Wei 
Published: December 2015

AbstractHerein, we introduce a new polypeptide‐functionalized mesoporous silica template fabricated from a biodegradable poly(ethylene oxide‐b‐ɛ‐caprolactone) (PEO‐b‐PCL) diblock copolymer and a poly(tyrosine) (PTyr) biopolymer. The crystallization behavior of the PEO‐b‐PCL diblock copolymer changes after blending, but the secondary structure of PTry remains stable. After selective solvent extraction in THF, the PEO‐b‐PCL is removed, but PTyr remains within the silica matrix due to its different solubility. Fourier‐transform IR spectroscopic analysis (FTIR), thermal gravitometry analysis (TGA), small‐angle X‐ray scattering (SAXS), and X‐ray diffraction (XRD) studies confirm the retention of PTyr to form a polypeptide‐functionalized mesoporous material. The adsorption of methylene blue hydrate (MB) from aqueous solution into the polypeptide‐functionalized mesoporous silica is investigated, thus revealing that the nanocomposite exhibits a high adsorption capacity relative to pure silica due to hydrogen‐bonding interactions between the hydroxy phenolic group of PTyr and the N‐containing aromatic ring from MB.
Iodide Recognition and Sensing in Water by a Halogen‐Bonding Ruthenium(II)‐Based Rotaxane
Authors: Langton Matthew J. , Marques Igor , Robinson Sean W. , Félix Vítor , Beer Paul D. 
Published: December 2015

AbstractThe synthesis and anion‐recognition properties of the first halogen‐bonding rotaxane host to sense anions in water is described. The rotaxane features a halogen‐bonding axle component, which is stoppered with water‐solubilizing permethylated β‐cyclodextrin motifs, and a luminescent tris(bipyridine)ruthenium(II)‐based macrocycle component. 1H NMR anion‐binding titrations in D2O reveal the halogen‐bonding rotaxane to bind iodide with high affinity and with selectively over the smaller halide anions and sulfate. The binding affinity trend was explained through molecular dynamics simulations and free‐energy calculations. Photo‐physical investigations demonstrate the ability of the interlocked halogen‐bonding host to sense iodide in water, through enhancement of the macrocycle component’s RuII metal–ligand charge transfer (MLCT) emission.
Stepwise Reduction of an α‐Phosphonio–Carbocation to a Crystalline Phosphorus Radical Cation and an Acridinyl–Phosphorus Ylide
Authors: Hudnall Todd W. , Dorsey Christopher L. , Jones James S. , Gabbaï François P. 
Published: December 2015

AbstractWe have synthesized the dicationic α‐phosphonio–carbocation 12+, which can be regarded as a two‐electron oxidized phosphorus ylide. Carbocation 12+ exhibits two reversible reduction waves at −0.28 and −0.90 V (vs. Fc+/Fc) indicating that both the radical cation 1.+ and the neural phosphorus ylide 1 can be generated. Indeed, reduction of 12+ with Zn afforded 1.+ as a dark green solid that was characterized by XRD and EPR spectroscopy, and reduction with Mg(Ant)⋅(THF)3 gave 1, which was characterized by 1H and 31P NMR spectroscopy. Computational analyses reveal the stepwise population of a C−P π bonding orbital upon reduction of 12+.
Monofluorination and Trifluoromethylation of BODIPY Dyes for Prolonged Single‐Molecule Detection
Authors: Huynh Anh Minh , Menges Johannes , Vester Michael , Dier Tobias , Huch Volker , Volmer Dietrich A. , Jung Gregor 
Published: December 2015

AbstractElectrophilic monofluorination with Selectfluor and nucleophilic trifluoromethylation with the Ruppert–Prakesh reagent of dimethyl‐, tetramethyl‐ and pentamethyl‐substituted boron dipyrromethenes (BODIPY) are investigated. Monofluorinated dyes are synthesized with low yields (<30 %), however trifluoromethyl derivatives are obtained in moderate to high yields (≈40–90 %). All compounds are characterized by steady‐state and time‐resolved fluorescence spectroscopy, the photostability is investigated with fluorescence correlation spectroscopy (FCS) and total internal reflection fluorescence microscopy (TIRF). Monofluorination hardly affects the spectroscopic parameters of the unsubstituted parent compounds, but distinctly enhances the photostability, whereas trifluoromethylation leads to a hypsochromic shift by up to 17 nm in both absorption and emission, slightly enhanced intersystem crossing, and higher photostability. Further development of soft fluorination and trifluoromethylation methods is therefore highly desired.