bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tailoring Supramolecular Nanotubes by Bile Salt Based Surfactant Mixtures
Authors: Gubitosi Marta , Travaglini Leana , di Gregorio Maria Chiara , Pavel Nicolae V. , Vázquez Tato José , Sennato Simona , Olsson Ulf , Schillén Karin , Galantini Luciano 
Published: April 2015

AbstractAn approach for tailoring self‐assembled tubular structures is described. By controlling the relative composition of a two‐component surfactant mixture comprising the natural bile salt lithocholate and its bolamphiphilic derivative, it was possible to finely tune the nanotube cross‐section of the mixed tubular aggregates that self‐associated spontaneously in aqueous solution at pH 12. The diameter was found to vary up to 50 % when the stoichiometric ratio of the two bile salts was changed. The tuning of supramolecular nanochannels with such remarkable precision is of significant interest for technological applications of these materials.
Reversible Hydrophobic–Hydrophilic Transition of Ionic Liquids Driven by Carbon Dioxide
Authors: Xiong Dazhen , Cui Guokai , Wang Jianji , Wang Huiyong , Li Zhiyong , Yao Kaisheng , Zhang Suojiang 
Published: April 2015

AbstractIonic liquids (ILs) with a reversible hydrophobic–hydrophilic transition were developed, and they exhibited unique phase behavior with H2O: monophase in the presence of CO2, but biphase upon removal of CO2 at room temperature and atmospheric pressure. Thus, coupling of reaction, separation, and recovery steps in sustainable chemical processes could be realized by a reversible liquid–liquid phase transition of such IL‐H2O mixtures. Spectroscopic investigations and DFT calculations showed that the mechanism behind hydrophobic–hydrophilic transition involved reversible reaction of CO2 with anion of the ILs and formation of hydrophilic ammonium salts. These unique IL‐H2O systems were successfully utilized for facile one‐step synthesis of Au porous films by bubbling CO2 under ambient conditions. The Au porous films and the ILs were then separated simultaneously from aqueous solutions by bubbling N2, and recovered ILs could be directly reused in the next process.
Bright Fluorescence and Host–Guest Sensing with a Nanoscale M4L6 Tetrahedron Accessed by Self‐Assembly of Zinc–Imine Chelate Vertices and Perylene Bisimide Edges
Authors: Frischmann Peter D. , Kunz Valentin , Würthner Frank 
Published: April 2015

AbstractA highly luminescent Zn4L6 tetrahedron is reported with 3.8 nm perylene bisimide edges and hexadentate ZnII–imine chelate vertices. Replacing FeII and monoamines commonly utilized in subcomponent self‐assembly with ZnII and tris(2‐aminoethyl)amine provides access to a metallosupramolecular host with the rare combination of structural integrity at concentrations <10−7 mol L−1 and an exceptionally high fluorescence quantum yield of Φem=0.67. Encapsulation of multiple perylene or coronene guest molecules is accompanied by strong luminescence quenching. We anticipate this self‐assembly strategy may be generalized to improve access to brightly fluorescent coordination cages tailored for host–guest light‐harvesting, photocatalysis, and sensing.
Wie der [NiFe4S4]‐Cluster der CO‐Dehydrogenase CO2 und NCO− aktiviert
Authors: Fesseler Jochen , Jeoung Jae‐Hun , Dobbek Holger 
Published: April 2015

AbstractNi,Fe‐haltige CO‐Dehydrogenasen (CODHs) nutzen einen [NiFe4S4]‐Cluster, auch C‐Cluster genannt, um CO2 mit hohen Umsatzzahlen reversibel zu CO zu reduzieren. Die Bindung an Ni und Fe aktiviert CO2, jedoch sind aktuelle Kristallstrukturen unzureichend aufgelöst, um die Geometrie des gebundenen CO2 zu analysieren und den Grad seiner Aktivierung zu enthüllen. Wir berichten hier über die Kristallstruktur von CODH im Komplex mit CO2 und dem zu CO2 isoelektronischen Inhibitor NCO− bei atomarer Auflösung (dmin≤1.1 Å). NCO− ist, wie CO2, ein μ2‐η2‐Ligand des Clusters und wirkt als Mechanismus‐abhängiger Inhibitor. Während gebundenes CO2 die Struktur einer Carboxylatgruppe besitzt, wird NCO− zu einer Carbamoylgruppe umgesetzt. Beide Moleküle durchlaufen damit eine formale Zweielektronenreduktion nach der Bindung und werden durch starke π‐Rückbindungen stabilisiert. Die Strukturen zeigen, dass der Umsatz von CO2 und die Inhibition durch NCO− auf der Kombination einer stabilen μ2‐η2‐Koordination zwischen Ni und Fe2 mit einer reduktiven Aktivierung beruhen.
Magnetic Assembly and Field‐Tuning of Ellipsoidal‐Nanoparticle‐Based Colloidal Photonic Crystals
Authors: Wang Mingsheng , He Le , Xu Wenjing , Wang Xin , Yin Yadong 
Published: April 2015

AbstractAnisotropic nanostructures provide an additional degree of freedom for tailoring the collective properties of their ensembles. Using Fe@SiO2 nanoellipsoids as anisotropic building blocks, herein we demonstrate a new class of magnetically responsive photonic structures whose photonic properties can be dynamically tuned by controlling the direction of the magnetic fields they are exposed to. These novel photonic structures diffract at a minimum wavelength when the field direction is perpendicular to the incident angle, and a maximum wavelength when the field is switched to parallel direction; and the diffraction intensity reaches maximum values when the fields are either parallel or perpendicular to the incident light, and decreases when the field direction is moved off‐angle.
Self‐Assembly of Disorazole C1 through a One‐Pot Alkyne Metathesis Homodimerization Strategy
Authors: Ralston Kevin J. , Ramstadius H. Clinton , Brewster Richard C. , Niblock Helen S. , Hulme Alison N. 
Published: April 2015

AbstractAlkyne metathesis is increasingly explored as a reliable method to close macrocyclic rings, but there are no prior examples of an alkyne‐metathesis‐based homodimerization approach to natural products. In this approach to the cytotoxic C2‐symmetric marine‐derived bis(lactone) disorazole C1, a highly convergent, modular strategy is employed featuring cyclization through an ambitious one‐pot alkyne cross‐metathesis/ring‐closing metathesis self‐assembly process.
White‐Light Emission Strategy of a Single Organic Compound with Aggregation‐Induced Emission and Delayed Fluorescence Properties
Authors: Xie Zongliang , Chen Chengjian , Xu Shidang , Li Jun , Zhang Yi , Liu Siwei , Xu Jiarui , Chi Zhenguo 
Published: April 2015

AbstractA novel white‐light‐emitting organic molecule, which consists of carbazolyl‐ and phenothiazinyl‐substituted benzophenone (OPC) and exhibits aggregation‐induced emission‐delayed fluorescence (AIE‐DF) and mechanofluorochromic properties was synthesized. The CIE color coordinates of OPC were directly measured with a non‐doped powder, which presented white‐emission coordinates (0.33, 0.33) at 244 K to 252 K and (0.35, 0.35) at 298 K. The asymmetric donor–acceptor–donor′ (D‐A‐D′) type of OPC exhibits an accurate inherited relationship from dicarbazolyl‐substituted benzophenone (O2C, D‐A‐D) and diphenothiazinyl‐substituted benzophenone (O2P, D′‐A‐D′). By purposefully selecting the two parent molecules, that is, O2C (blue) and O2P (yellow), the white‐light emission of OPC can be achieved in a single molecule. This finding provides a feasible molecular strategy to design new AIE‐DF white‐light‐emitting organic molecules.
Scalable Synthesis of the Potent HIV Inhibitor BMS‐986001 by Non‐Enzymatic Dynamic Kinetic Asymmetric Transformation (DYKAT)
Authors: Ortiz Adrian , Benkovics Tamas , Beutner Gregory L. , Shi Zhongping , Bultman Michael , Nye Jeffrey , Sfouggatakis Chris , Kronenthal David R. 
Published: April 2015

AbstractDescribed herein is the synthesis of BMS‐986001 by employing two novel organocatalytic transformations: 1) a highly selective pyranose to furanose ring tautomerization to access an advanced intermediate, and 2) an unprecedented small‐molecule‐mediated dynamic kinetic resolution to access a variety of enantiopure pyranones, one of which served as a versatile building block for the multigram, stereoselective, and chromatography‐free synthesis of BMS‐986001. The synthesis required five chemical transformations and resulted in a 44 % overall yield.
Ring Tension Applied to Thiol‐Mediated Cellular Uptake
Authors: Gasparini Giulio , Sargsyan Gevorg , Bang Eun‐Kyoung , Sakai Naomi , Matile Stefan 
Published: April 2015

AbstractThe objective of the study was to explore the potential of ring tension in cyclic disulfides for thiol‐mediated cellular uptake. Fluorescent probes that cannot enter cells were equipped with cyclic disulfides of gradually increasing ring tension. As demonstrated by flow cytometry experiments, uptake into HeLa Kyoto cells increased with increasing tension. Differences in carbon‐sulfur‐sulfur‐carbon (CSSC) dihedral angles as small as 8° caused significant changes in uptake efficiency. Uptake with high ring tension was better than with inactivated or activated linear disulfides or with thiols. Conversion of thiols on the cell surface into sulfides and disulfides decreased the uptake. Reduction of exofacial disulfides into thiols increased the uptake of transporters with disulfides and inactivated controls with thiols. These results confirm the occurrence of dynamic covalent disulfide‐exchange chemistry on cell surfaces. Mechanistic and colocalization studies indicate that endocytosis does not fully account for this cellular uptake with ring tension.
Epitope Targeting of Tertiary Protein Structure Enables Target‐Guided Synthesis of a Potent In‐Cell Inhibitor of Botulinum Neurotoxin
Authors: Farrow Blake , Wong Michelle , Malette Jacquie , Lai Bert , Deyle Kaycie M. , Das Samir , Nag Arundhati , Agnew Heather D. , Heath James R. 
Published: April 2015

AbstractBotulinum neurotoxin (BoNT) serotype A is the most lethal known toxin and has an occluded structure, which prevents direct inhibition of its active site before it enters the cytosol. Target‐guided synthesis by in situ click chemistry is combined with synthetic epitope targeting to exploit the tertiary structure of the BoNT protein as a landscape for assembling a competitive inhibitor. A substrate‐mimicking peptide macrocycle is used as a direct inhibitor of BoNT. An epitope‐targeting in situ click screen is utilized to identify a second peptide macrocycle ligand that binds to an epitope that, in the folded BoNT structure, is active‐site‐adjacent. A second in situ click screen identifies a molecular bridge between the two macrocycles. The resulting divalent inhibitor exhibits an in vitro inhibition constant of 165 pM against the BoNT/A catalytic chain. The inhibitor is carried into cells by the intact holotoxin, and demonstrates protection and rescue of BoNT intoxication in a human neuron model.
Unwinding of the C‐Terminal Residues of Neuropeptide Y is critical for Y2 Receptor Binding and Activation
Authors: Kaiser Anette , Müller Paul , Zellmann Tristan , Scheidt Holger A. , Thomas Lars , Bosse Mathias , Meier Rene , Meiler Jens , Huster Daniel , Beck‐Sickinger Annette G. , Schmidt Peter 
Published: April 2015

AbstractDespite recent breakthroughs in the structural characterization of G‐protein‐coupled receptors (GPCRs), there is only sparse data on how GPCRs recognize larger peptide ligands. NMR spectroscopy, molecular modeling, and double‐cycle mutagenesis studies were integrated to obtain a structural model of the peptide hormone neuropeptide Y (NPY) bound to its human G‐protein‐coupled Y2 receptor (Y2R). Solid‐state NMR measurements of specific isotope‐labeled NPY in complex with in vitro folded Y2R reconstituted into phospholipid bicelles provided the bioactive structure of the peptide. Guided by solution NMR experiments, it could be shown that the ligand is tethered to the second extracellular loop by hydrophobic contacts. The C‐terminal α‐helix of NPY, which is formed in a membrane environment in the absence of the receptor, is unwound starting at T32 to provide optimal contacts in a deep binding pocket within the transmembrane bundle of the Y2R.
Cationic Titanocene(III) Complexes for Catalysis in Single‐Electron Steps
Authors: Gansäuer Andreas , Hildebrandt Sven , Michelmann Antonius , Dahmen Tobias , von Laufenberg Daniel , Kube Christian , Fianu Godfred D. , Flowers Robert A. 
Published: April 2015

AbstractBy exploiting solvent and anion effects, [Cp2Ti]+complexes for atom‐economical catalysis in single‐electron steps were developed and applied for the first time. These complexes constitute remarkably stable and active catalysts for radical arylations. The reaction kinetics and catalyst composition were studied by cyclic voltammetry and in situ IR spectroscopy.
A Small Molecule Walks Along a Surface Between Porphyrin Fences That Are Assembled In Situ
Authors: Haq Sam , Wit Bareld , Sang Hongqian , Floris Andrea , Wang Yu , Wang Jianbo , Pérez‐García Lluïsa , Kantorovitch Lev , Amabilino David B. , Raval Rasmita 
Published: April 2015

AbstractAn on‐surface bimolecular system is described, comprising a simple divalent bis(imidazolyl) molecule that is shown to “walk” at room temperature via an inchworm mechanism along a specific pathway terminated at each end by oligomeric “fences” constructed on a monocrystalline copper surface. Scanning tunneling microscopy shows that the motion of the walker occurs along the [1$\bar 1$0] direction of the Cu surface with remarkably high selectivity and is effectively confined by the orthogonal construction of covalent porphyrin oligomers along the [001] surface direction, which serve as barriers. Density functional theory shows that the mobile molecule walks by attaching and detaching the nitrogen atoms in its imidazolyl “legs” to and from the protruding close‐packed rows of the metal surface and that it can transit between two energetically equivalent extended and contracted conformations by overcoming a small energy barrier.
Unsaturated polyester resins for thermoset applications using renewable isosorbide as a component for property improvement
Authors: Sadler Joshua M. , Toulan Faye R. , Palmese Giuseppe R. , La Scala John J. 
Published: April 2015

ABSTRACTUnsaturated polyester (UPE) resins are used in a variety of thermosetting applications due to the reduced cost when compared to epoxy resins; however, UPE resins also have reduced thermomechanical performance. Investigating avenues to improve the performance of UPEs has led to the use of bio‐based starting materials as structural components of the synthesized prepolymers as a result of their advantageous structural features. Isosorbide, a compound derived from renewable feedstocks, has been utilized to provide additional stiffness from the diol component for novel unsaturated polyesters resins. These resins have been shown to possess Tg's (32−72°C) and storage moduli (540−2200 MPa) that are in the desired range for composite materials with viscosities (1.2−25 Pa s) amenable to a variety of liquid molding techniques. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42315.
An alternative approach in regulation of expression of a transgene by endogenous miR‐145 in carcinoma and normal breast cell lines
Authors: Ghanbari Safari Maryam , Baesi Kazem , Hosseinkhani Saman 
Published: April 2015

AbstractMicroRNAs are small noncoding RNAs that regulate gene expression by repressing translation of target cellular transcripts. Increasing evidences indicate that miRNAs have different expression profiles and play crucial roles in numerous cellular processes. Delivery and expression of transgenes for cancer therapy must be specific for tumors to avoid killing of healthy tissues. Many investigators have shown that transgene expression can be suppressed in normal cells using vectors that are responsive to microRNA regulation. To overcome this problem, miR‐145 that exhibits downregulation in many types of cancer cells was chosen for posttranscriptional regulatory systems mediated by microRNAs. In this study, a psiCHECK‐145T vector carrying four tandem copies of target sequences of miR‐145 into 3’‐UTR of the Renilla luciferase gene was constructed. Renilla luciferase activity from the psiCHECK‐145T vector was 57% lower in MCF10A cells with high miR‐145 expression as compared to a control condition. Additionally, overexpression of miR‐145 in MCF‐7 cells with low expression level of miR‐145 showed more than 76% reduction in the Renilla luciferase activity from the psiCHECK‐145T vector. Inclusion of miR‐145 target sequences into the 3′‐UTR of the Renilla luciferase gene is a feasible strategy for restricting transgene expression in a breast cancer cell line while sparing a breast normal cell line.
Fluorescence spectroscopy and docking study in two flavonoids, isolated tectoridin and its aglycone tectorigenin, interacting with human serum albumin: a comparison study
Authors: Li Yuanzhi , Wang Qing , He Jiawei , Yan Jin , Li Hui 
Published: April 2015

AbstractTwo flavonoids, tectoridin (TD) isolated from rhizomes of Iris tectorum and hydrolyzed aglycone tectorigenin (TG) were prepared and characterized to compare their different interaction ability with human serum albumin (HSA). Based on the results, the affinity of TG–HSA was stronger than that of TD–HAS, and TG combined more closely with HSA than did TD. HSA fluorescence was quenched by TD/TG. The interactions between TD/TG and HSA involved static quenching. The thermodynamic parameters indicated that both binding processes were spontaneous; hydrogen binding and van der Waals force were the main forces between TD and HSA, whereas a hydrophobic interaction was the main binding force between TG and HSA. Synchronous and 3D fluorescence spectra showed that the binding of TD/TG to HSA induced conformational changes. Moreover, a docking study confirmed the experimental results. Copyright © 2015 John Wiley & Sons, Ltd.
Realistic and stable animation of cloth
Authors: Yao Junfeng , Lan Lei , Lin Wenlin , She Yingying , Zhang Binbin 
Published: April 2015

AbstractResearchers have proposed various techniques for cloth simulation in the last decades. The crucial problem in interactive animation for cloth is how to speed up simulation with a stable system. In this paper, we describe a realistic and stable scheme for cloth simulation based on mass‐spring system. This scheme modifies semi‐implicit integration used in cloth simulation system with an efficient damping method. Semi‐implicit integration methods have been widely used in dynamic simulation because of acceptable speed and stability. However, internal damping forces are generated with respect to rotational rigid motions, which are only depending on relative velocities. Undesirable change in global movement of dynamic cloth could result in damping artifact. We replace the internal damping forces with an optimal damping method which is based on iterative spring damping but the limit can be computed directly. The method provides simple damping parameter estimation and guarantees conservation of global movement. As a result, complex clothes can be realistically and stably simulated in real time. Copyright © 2015 John Wiley & Sons, Ltd.
PCMD: personality‐characterized mood dynamics model toward personalized virtual characters
Authors: Zhang Juzheng , Zheng Jianmin , Magnenat‐Thalmann Nadia 
Published: April 2015

AbstractHow to endow the virtual characters with personalized behavior patterns remains a challenging problem. Instead of heuristically designing behaviors for certain personalities, this paper bridges the gap between personalities and behaviors using a medium concept, mood, to make the behaviors of the characters consistent enough to convey their personalities, while flexible enough to make appropriate response in various situations. We propose a personality‐characterized mood dynamics model, in which the emotion weights are computed as a solution of a convex optimization problem that is constructed to make the overall mood approaches the personality after sufficient interactions. The convergence of the algorithm is demonstrated by numerical simulations. The implementation of the personality‐characterized mood dynamics model enables an emotion‐oriented virtual human, Sophie, to show personalized behaviors in the emotional interactions with users. Copyright © 2015 John Wiley & Sons, Ltd.
Snapshot quiz – recurrent right iliac fossa pain in the patient with a previous history of appendicitis
Authors: Aris Chandran Johan , Cobb Will A. , Keeler Barrie D. , Soin Bob 
Published: April 2015

Key Clinical MessageA low threshold for computed tomography (CT) scanning in patients with previous appendicectomy and right iliac fossa pain helps facilitate timely diagnosis and exclusion of other differential diagnoses. Here, we present a rare cause which has significant medicolegal ramifications and is accurately diagnosed with CT.
Continuous Transfer Hydrogenation of Sugars to Alditols with Bioderived Donors over Cu–Ni–Al Catalysts
Authors: Scholz David , Aellig Christof , Mondelli Cecilia , Pérez‐Ramírez Javier 
Published: April 2015

AbstractThe transfer hydrogenation of sugars to alditols with biobased alcohol donors was studied over hydrotalcite‐derived Cu6−xNixAl2 catalysts prepared by coprecipitation at different pH and featuring variable Cu/Ni ratios. Their evaluation, after in situ activation in pure H2 at 773 K, in the ethanol‐assisted upgrading of glucose in a continuous‐flow fixed‐bed reactor identified the solid synthesized at pH 9–10 and with Cu/Ni=1 as the best performer. Based on textural, structural, and redox analyses, this is related to an enhanced intermetallic interaction. Upon screening alternative donors, a sorbitol yield as high as 67 % was achieved with 1,4‐butanediol. The catalytic system displayed a stable behavior during 48 h on stream and proved suitable to hydrogenate also fructose, mannose, xylose, and arabinose to the corresponding polyols (yields up to 65 %), thus standing as a more sustainable and economical alternative to Ru‐based catalysts for sugar reductive upgrading.
Thermally Induced Strains on the Catalytic Activity and Stability of Pt–M2O3/C (M=Y or Gd) Catalysts towards Oxygen Reduction Reaction
Authors: Luo Yun , Habrioux Aurélien , Calvillo Laura , Granozzi Gaetano , Alonso‐Vante Nicolas 
Published: April 2015

AbstractYttrium oxide and gadolinium oxide modified platinum nanoparticles supported on carbon (Vulcan XC‐72), noted as Pt–M2O3/C (M=Y and Gd), were synthesized by water‐in‐oil nanoemulsion chemical route, followed by heat treatment at 100 and 300 °C under hydrogen/nitrogen (H2/N2) atmosphere and tested as electrocatalysts for the oxygen reduction reaction (ORR). As revealed by powder X‐ray diffraction analysis, all obtained catalysts showed solely Pt face‐centered‐cubic structure, and absence of a secondary phase before and after heat treatments, indicating that Y2O3 and Gd2O3 are highly disordered (amorphous) and dispersed clusters. The surface Pt:M ratio (M=Y and Gd), as revealed by X‐ray photoelectron spectroscopy, increased after heat treatment with respect to the value of as‐prepared samples, for which the ratio was 1:1. Microstrain data extracted from Williamson–Hall plots for Pt–M2O3/C (M=Y and Gd) catalysts surprisingly increased after heat treatment at 100 °C, remaining nearly constant after heat treatment at 300 °C, whereas the value of pure Pt nanoparticles, noted as Pt/C, decreased after heat treatments. The mean particle size derived from TEM images for Pt–M2O3/C (M=Y and Gd) was almost unchanged after heat treatments, at variance with the Pt/C case where a clear increase is observed. Surface specific activity and mass activity towards ORR obtained with as‐prepared Pt–M2O3/C (M=Y and Gd) catalysts were higher than those of as‐prepared Pt/C catalyst. After heat treatment, the ORR activity of Pt–M2O3/C (M=Y and Gd) augmented, whereas that of Pt/C diminished. Moreover, after 6000 cycles between 0.5 and 0.95 V versus reversible hydrogen electrode (vs. RHE), Pt–M2O3/C (M=Y and Gd) catalysts retained a large active surface area and a high kinetic current density at 0.9 V vs. RHE in comparison with Pt/C samples. These facts assess a positive effect of the interaction between M2O3 (M=Y and Gd) and Pt catalytic centers both on the catalytic activity of the material towards ORR and on its durability.