bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature‐ and Pressure‐Induced Switching of the Molecular Spin State of an Orthorhombic Iron(III) Spin‐Crossover Salt
Authors: Tissot Antoine , Shepherd Helena J. , Toupet Loic , Collet Eric , Sainton Joelle , Molnár Gabor , Guionneau Philippe , Boillot Marie‐Laure 
Published: December 2012

AbstractThe [(TPA)FeIII(TCC)]+ complex [TPA = tris(2‐pyridylmethyl)amine, TCC2– = 3,4,5,6‐tetrachlorocatecholate dianion] forms a molecular solid with the SbF6– anion, which exhibits an incomplete S = 1/2 ↔ S = 5/2 thermal spin‐crossover process centered at 250 K. Single‐crystal X‐ray diffraction, Raman spectroscopy, and magnetic measurements of this orthorhombic polymorph were performed to delineate the spin‐state thermo‐ and piezoswitching in relation to the structural and elastic properties. Indeed, a pressure‐induced spin crossover (centered at P1/2 ≈ 1.65 kbar, T = 294 K) concomitant with unit‐cell contraction was observed by applying a hydrostatic pressure to the single crystal. Under ambient conditions, the piezo‐induced transition, like that induced thermally, is relatively gradual, which probably reflects a similar mechanism in response to both stimuli. Except for a 47 K shift, the spin‐crossover curves of the isostructural SbF6– and PF6– salts compare well. They are discussed with respect to structural anisotropy and pressure effects.
Factors That Determine the Mechanism of NO Activation by Metal Complexes of Biological and Environmental Relevance
Authors: Franke Alicja , van Eldik Rudi 
Published: December 2012

AbstractThis account presents a sampling of kinetic and mechanistic investigations on the activation of nitric oxide (NO) by metal complexes of biological and environmental importance. Throughout the review the main emphasis falls on the finding and characterization of factors that control the dynamics of NO–metal interactions in which the metal centers serve as coordination and electron‐transfer mediators. On the basis of the systems surveyed, several important aspects concerning the mechanism of NO activation processes have been evaluated and are discussed in detail. They involve the effect of (i) chemical properties of the reaction medium, (ii) electronic nature of the leaving ligand, (iii) environment of the coligands, and (iv) steric hindrance around the metal active center, on the reversible binding of NO to metal complexes, as well as on the electronic nature and reactivity of metal activated forms of nitric oxide in the resulting nitrosyl products. The conclusions drawn from the work summarized in this review, along with a comparison with data available for other related systems, add a valuable piece to the puzzle of the complex mechanistic picture that describes the process of metal‐assisted activation of nitric oxide.
A Flexible Chelate Leads to Phototriggered Isomerization in an Osmium Sulfoxide Complex
Authors: Garg Komal , Paris Shadrick I. M. , Rack Jeffrey J. 
Published: December 2012

AbstractWe report the preparation and spectroscopic properties of [Os(bpy)2(pySO)]2+ and [Os(bpy)2(pySOCF3)]2+, where bpy is 2,2′‐bipyridine, pySO is 2‐(propane‐2‐sulfinylmethyl)pyridine, and pySOCF3 is 2‐[(trifluoroethylsulfinyl)methyl]pyridine. The charge‐transfer absorption spectra of [Os(bpy)2(pySO)]2+ and [Os(bpy)2(pySOCF3)]2+ are 378 and 367 nm, respectively. Charge‐transfer excitation of [Os(bpy)2(pySOCF3)]2+ shows substantial changes in the UV/Vis spectrum with a shift in the lowest energy absorption maximum from 367 to 415 nm, which is consistent with phototriggered S→O isomerization. Irradiation of [Os(bpy)2(pySO)]2+ shows no evidence of isomerization. Cyclic voltammograms of [Os(bpy)2(pySO)]2+ and [Os(bpy)2(pySOCF3)]2+ feature reversible one‐electron couples that are ascribed to Os3+/2+ reduction potentials (E°′) at 1.01 V (vs Ag/AgCl; $\tilde {\nu}$ = 0.1 V/s; CH3CN; 0.1 M TBAPF6) and 1.17 V, respectively. Femtosecond to nanosecond transient absorption spectra for [Os(bpy)2(pySOCF3)]2+ are reported. For [Os(bpy)2(pySOCF3)]2+, fits of data obtained at 370 nm yield lifetimes of 0.20 (±0.02) and 19.7 (±8) ps, whereas for [Os(bpy)2(pySO)]2+ lifetimes of 0.47 (±0.2) and 12.7 (±11) ps are obtained at 378 nm. These lifetimes are ascribed to the formation of a 3MLCT state and solvent reorganization, respectively. Excited state lifetimes of 331(±4) and 348 (±25) ns are found for [Os(bpy)2(pySO)]2+ and [Os(bpy)2(pySOCF3)]2+, respectively. The time constant for isomerization is 213 μs for [Os(bpy)2(pySOCF3)]2+. Transient absorption spectra reveal an excited state sulfoxide to Os3+ transition. The electrochemical and spectroscopic data can be combined to yield electronic state diagrams for [Os(bpy)2(pySO)]2+ and [Os(bpy)2(pySOCF3)]2+.
Amino Acid Derivatives of Tetrathiafulvalene and Their N–H···O Peptide Bond Dipoles‐Templated Solid State Assemblies
Authors: El‐Ghayoury Abdelkrim , Zorina Leokadiya , Simonov Sergey , Sanguinet Lionel , Batail Patrick 
Published: December 2012

AbstractWe report on a series of amino acid derivatives of tetrathiafulvalene as well as on the structure‐directing abilities of their peptide residues in the crystalline solid state to stabilize patterns of interactions such as β strands and sheet motifs. Characteristic hydrogen‐bonding motifs are indeed identified within ethylenedithiotetrathiafulvalene (EDT‐TTF) and dimethyltetrathiafulvalene (Me2‐TTF) based compounds 1–5. Esters 1–3 contain hydrogen‐bond acceptors, namely carbonyl groups, as well as one strong (NH) and one weak (C–H) hydrogen‐bond donor. In addition to the hydrogen‐bonded sets of ester derivatives, acids 4 and 5 present the carboxylic acid moiety, which acts as both a hydrogen‐bond donor and acceptor. EDT‐TTF‐CO‐GlyOH has been previously used to afford a new type of hydrogen‐bonded acid/zwitterion (1:1) hybrid admixture of redox peptidics.
A Protection‐Free Synthetic Access to (±)‐1‐Deoxy‐6‐epi‐castanospermine and (±)‐1‐Deoxy‐6,8a‐di‐epi‐castanospermine
Authors: Serafidou Angeliki‐Theodora , Yioti Efthymia G. , Gallos John K. 
Published: December 2012

AbstractA new synthesis of (±)‐1‐deoxy‐6‐epi‐castanospermine and (±)‐1‐deoxy‐6,8a‐di‐epi‐castanospermine has been developed, starting from the hetero‐Diels–Alder adduct of ethyl 2‐nitrosoacrylate and ethyl vinyl ether. Appropriate terminal dienes were prepared by standard manipulations, which, upon RCM followed by dihydroxylation and catalytic Raney Ni hydrogenation, led to the title compounds, which are of significant biological interest. The whole synthesis was completed in eight steps, and no protecting groups were needed in any step.
Synthesis of 3,4‐Dihydroisoquinolin‐1‐ones from N‐Boc‐(β‐Arylethyl)carbamates via Isocyanate Intermediates
Authors: In Jinkyung , Hwang Soonho , Kim Changhun , Seo Jae Hong , Kim Sanghee 
Published: December 2012

AbstractMild reaction conditions for the regioselective synthesis of isoquinolin‐1‐ones and related fused‐ring heterocycles from N‐Boc‐protected (β‐arylethyl)carbamates are described. The reactions involved the use of Tf2O and 2‐chloropyridine and isocyanates are likely to be key intermediates. The method was extended to substrates bearing less nucleophilic aryl moieties by using Lewis acid additives, such as BF3·Et2O, to enhance the Friedel–Crafts‐type cyclization of the isocyanate intermediates. This method allowed the synthesis of various substituted isoquinolin‐1‐ones, β‐carbolines, thiophene‐fused ring systems and tetrahydrobenzoazepin‐1‐ones in good yields and with high regioselectivities.
Skin‐draining lymph node priming is sufficient to induce sterile immunity against pre‐erythrocytic malaria
Authors: Obeid Michel , Franetich Jean‐François , Lorthiois Audrey , Gego Audrey , Grüner Anne Charlotte , Tefit Maurel , Boucheix Claude , Snounou Georges , Mazier Dominique 
Published: December 2012

AbstractThe Plasmodium‐infected hepatocyte has been considered necessary to prime the immune responses leading to sterile protection after vaccination with attenuated sporozoites. However, it has recently been demonstrated that priming also occurs in the skin. We wished to establish if sterile protection could be obtained in the absence of priming by infected hepatocytes. To this end, we developed a subcutaneous (s.c.) immunization protocol where few, possibly none, of the immunizing irradiated Plasmodium yoelii sporozoites infect hepatocytes, and also used CD81‐deficient mice non‐permissive to productive hepatocyte infections. We then compared and contrasted the patterns of priming with those obtained by intradermal immunization, where priming occurs in the liver. Using sterile immunity as a primary read‐out, we exploited an inhibitor of T‐cell migration, transgenic mice with conditional depletion of dendritic cells and adoptive transfers of draining lymph node‐derived T cells, to provide evidence that responses leading to sterile immunity can be primed in the skin‐draining lymph nodes with little, if any, contribution from the infected hepatocyte.
Early primate evolution in Afro‐Arabia
Authors: Seiffert Erik R. 
Published: December 2012

AbstractThe peculiar mammalian fauna that inhabited Afro‐Arabia during the Paleogene first came to the attention of the scientific community in the early part of the twentieth century, when Andrews1 and Schlosser2 published their landmark descriptions of fossil mammals from the Fayum Depression in northern Egypt. Their studies revealed a highly endemic assemblage of land mammals that included the first known Paleogene records of hyraxes, proboscideans, and anthropoid primates, but which lacked ancestors of many iconic mammalian lineages that are found in Africa today, such as rhinos, zebras, bovids, giraffes, and cats. Over the course of the last century, the Afro‐Arabian Paleogene has yielded fossil remains of several other endemic mammalian lineages,3 as well as a diversity of prosimian primates,4 but we are only just beginning to understand how the continent's faunal composition came to be, through ancient processes such as the movement of tectonic plates, changes in climate and sea level, and early phylogenetic splits among the major groups of placental mammals. These processes, in turn, made possible chance dispersal events that were critical in determining the competitive landscape–and, indeed, the survival–of our earliest anthropoid ancestors. Newly discovered fossils indicate that the persistence and later diversification of Anthropoidea was not an inevitable result of the clade's competitive isolation or adaptive superiority, as has often been assumed, but rather was as much due to the combined influences of serendipitous geographic conditions, global cooling, and competition with a group of distantly related extinct strepsirrhines with anthropoid‐like adaptations known as adapiforms. Many of the important details of this story would not be known, and could never have been predicted, without the fossil evidence that has recently been unearthed by field paleontologists. © 2012 Wiley Periodicals, Inc.
Annealing of Nafion 1100 in the Presence of an Annealing Agent: A Powerful Method for Increasing Ionomer Working Temperature in PEMFCs
Authors: Alberti G. , Narducci R. , Di Vona M. L. , Giancola S. 
Published: December 2012

AbstractThe possibility of increasing the working temperature of fuel cells using Nafion as ionomer membranes by a new annealing procedure in the presence of dimethylsulfoxide or tributylphosphate as annealing agents has been investigated. The extent of annealing was derived by the shift of nc/T plots of annealed membranes (nc is the index of counter‐elastic force) relatively to the plot of as received membranes. nc/T plots can be used as a powerful analytical method useful for deriving quantitative information on the annealing extent and for obtaining information on the melting temperature of the semi‐crystalline phase grown during annealing. It was found that, by using an annealing temperature of 140 °C in the presence of an annealing agent, an important effect on the thermal stability of Nafion membranes was obtained. The increased thermal stability was related to the increase of the original semi‐crystalline phase which acts as a physical cross‐linker so that the mechanical properties are no longer lost at the glass transition temperature but at the melting point of the semi‐crystalline phase. The use of nc/T plots as analytical tools for detecting and understanding important ionomer properties was denominated as “Ionomer nc Analysis” (INCA).
Uncertainty quantification of CO2 leakage through a fault with multiphase and nonisothermal effects
Authors: Lu Chuanhe , Sun Yunwei , Buscheck Thomas A. , Hao Yue , White Joshua A. , Chiaramonte Laura 
Published: December 2012

AbstractThe potential for CO2 leakage through a permeable fault is a key concern for geologic CO2 sequestration (GCS) in saline formations. If CO2 migrates vertically upward through a fault from the storage reservoir to an overlying fresh‐water aquifer, phase change can occur because temperature and pressure decrease with decreasing depth. The decrease in CO2 density during phase transition causes an additional reduction in temperature. In this paper, we present a computational model for simulating the behaviour of a leaky fault connecting a saline CO2 storage reservoir and an overlying fresh‐water aquifer. We address phase transition, considering the nonlinear CO2 enthalpy and viscosity functions. The model results indicate that the CO2 leakage rate initially increases when CO2 migration is driven by both buoyancy and overpressure during the period of injection. In the post‐injection period, CO2 leakage is only driven by buoyancy and the leakage rate decreases. The influence of nonisothermal conditions is more pronounced during the first stage. The deterministic model of this faulted reservoir system is used within an uncertainty quantification (UQ) framework to rigorously quantify the sensitivity of the brine and CO2 leakage in response to the uncertain model parameters. The results demonstrate that fault permeability is the most sensitive factor affecting both CO2 and brine leakage rate. Reduced‐order models of CO2 and brine leakage are developed for the emulation of a large number of sample points, from which probability distributions are derived and can be incorporated in risk assessment of groundwater contamination resulting from CO2 and brine leakage. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd
Formal Synthesis of (−)‐Cephalotaxine
Authors: Gonçalves‐Martin Monica G. , Zigmantas Sarunas , Renaud Philippe 
Published: December 2012

AbstractA formal synthesis of (−)‐cephalotaxine (1) by means of a highly stereoselective radical carboazidation process is reported. The synthesis begins with the protected (S)‐cyclopent‐2‐en‐1‐ol derivative 10 and uses the concept of self‐reproduction of a stereogenic center (Schemes 5 and 6). For this purpose, the double bond adjacent to the initial chiral center in 10 is converted into an acetonide after stereoselective dihydroxylation. The initial alcohol function is used to build an exocyclic methylene group suitable for the carboazidation process 8→7 (Scheme 7). Finally the protected diol moiety is converted back to an alkene (14→15→6) and used for the formation of ring B via a Heck reaction (6→(−)‐16; Scheme 8).
Alkylations of Chiral Nickel(II) Complexes of Glycine under Phase‐Transfer Conditions
Authors: Houck Daniel , Luis Aceña José , Soloshonok Vadim A. 
Published: December 2012

AbstractAlkylation reactions of nickel(II) complex 6 derived from glycine and 2‐[(1‐benzyl‐L‐prolyl)amino]benzophenone (BPBP) were studied under phase‐transfer‐catalysis (PTC) conditions. The goal of this work was to find an alternative suitable solvent for these reactions to replace the commonly used CH2Cl2 which leads to the formation of several by‐products, thus lowering the yield of target compounds. We demonstrate that 1,2‐dichloroethane is a markedly better solvent providing higher yields (75–99%) of the desired products 10 with 36–88% diastereoisomer purity (Scheme 3 and Table). Furthermore, we show that the stereochemical outcome of these PTC reactions (kinetic control) can be easily improved to >95% de by treatment of the PTC products with MeONa/MeOH. The scope of these reactions includes alkylations with methyl iodide as well as activated halides such as benzyl, allyl or propargyl, bromides and most notably ethyl 2‐bromoacetate (Table).
Organization Change and Social Organizing Strategies: Employee‐Initiated Organization Development
Authors: Githens Rod Patrick 
Published: December 2012

AbstractLesbian, gay, bisexual, transgender, and queer (LGBTQ) employees create formal and informal groups within workplaces to provide social support and to seek organizational change at their places of employment. I present a case study of a coalition of these groups working together to attain domestic partner benefits within a large three‐campus university system. These groups worked together to conduct employee‐initiated organization development (OD). This development occurred through various approaches to organizational change and social organizing strategies. The study illustrates the distinct differences between employee‐initiated OD in the corporate sector and in universities. It also demonstrates the utility in organizing through a structured activist group and a looser grassroots coalition at various stages of the effort. Successes were attained at various stages through both the more highly structured groups and through loose‐knit coalitions. Additionally, this study illustrates successes in social organizing around both fixed, ethnic‐type identities and through more fluid queer approaches. Both approaches were utilized to varying degrees as the activists worked toward goals of concern to (a) diverse groups (not just LGBTQ individuals) and (b) LGBTQ‐specific constituents.
Commitment to Change: Its Role in the Relationship Between Expectation of Change Outcome and Emotional Exhaustion
Authors: Ning Jing , Jing Runtian 
Published: December 2012

AbstractSuccessful implementation of organizational changes greatly depends on committed employees. It is crucial for managers, leaders, and HRD professionals to understand the antecedents and outcomes of commitment to change. The purpose of this study is to investigate the relationships among expectation of change outcome at the individual level, commitment to change, and emotional exhaustion. Four hundred and sixty‐three usable surveys were returned from managers and employees from three companies in the Chinese telecom industry that were undergoing large‐scale organizational changes. Results of correlation analysis demonstrated that expectation of change outcome was positively correlated with affective and normative commitments to change and negatively correlated with continuance commitment to change. Affective and normative commitments to change were both negatively correlated with emotional exhaustion, while continuance commitment to change was positively correlated with emotional exhaustion. Structural equation modeling analysis indicated that a full mediation model fitted best to the data. The relationships between the two dimensions of expectation of change outcome and emotional exhaustion were fully mediated by affective and normative commitments to change. This study offers insights into understanding the complex nature of commitment to change, how to cultivate commitment to change, and how to use commitment to change as an intervention solution to reduce stress.
Part I: Development and optimization of solid‐lipid nanoparticles using Box–Behnken statistical design for ocular delivery of gatifloxacin
Authors: Kalam Mohd. Abul , Sultana Yasmin , Ali Asgar , Aqil Mohd. , Mishra Anil K. , Aljuffali Ibrahim A. , Alshamsan Aws 
Published: December 2012

AbstractThis study aims to improve gatifloxacin bioavailability to the eye using solid‐lipid nanoparticles (SLN). Cationic SLNs were prepared by o/w‐microemulsion method using stearylamine. The generated formulations were optimized by three‐factor, three‐level Box–Behnken statistical design. The independent variables were the lipidmix concentration (X1), poloxamers‐188 (X2), and sodium‐taurocholate (X3), while the dependent variables were drug release (Y1), encapsulation efficiency (EE) (Y2), and particle size (Y3) with applied constraints of maximizing drug release and EE and minimizing particle size. Response surface plots were drawn, statistical validity of the polynomials was established, optimized formulations were selected by feasibility and grid search, and the optimization process was validated. Particle size, polydispersity index, and zeta‐potentials were measured by photon correlation spectroscopy. Particle's morphology was evaluated by transmission electron microscopy. Differential scanning calorimetry (DSC) and wide‐angle X‐ray diffraction (WXRD) studies were performed to characterize state of drug and lipid modification. SLN size was (250–305 nm) and zeta‐potential (29–36 mV) after 3‐month storage. Entrapment efficiencies were 46.58 and 78.55%, and loading efficiencies were 29.60 and 20.70 for SLN‐C and SLN‐D, respectively. DSC and WXRD analyses showed low‐crystalline SLN and amorphous drug dispersion in SLN. In vitro release data were fitted to release kinetics equations, where the release pattern was found to follow Korsmeyer–Peppas model. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Robotic deposition and in vitro characterization of 3D gelatin−bioactive glass hybrid scaffolds for biomedical applications
Authors: Gao Chunxia , Rahaman Mohamed N. , Gao Qiang , Teramoto Akira , Abe Koji 
Published: December 2012

AbstractThe development of inorganic−organic hybrid scaffolds with controllable degradation and bioactive properties is receiving considerable interest for bone and tissue regeneration. The objective of this study was to create hybrid scaffolds of gelatin and bioactive glass (BG) with a controlled, three‐dimensional (3D) architecture by a combined sol−gel and robotic deposition (robocasting) method and evaluate their mechanical response, bioactivity, and response to cells in vitro. Inks for robotic deposition of the scaffolds were prepared by dissolving gelatin in a sol−gel precursor solution of the bioactive glass (70SiO2−25CaO−5P2O5; mol%) and aging the solution to form a gel with the requisite viscosity. After drying and crosslinking, the gelatin−BG scaffolds, with a grid‐like architecture (filament diameter ∼350 µm; pore width ∼550 µm), showed an elasto−plastic response, with a compressive strength of 5.1 ± 0.6 MPa, in the range of values for human trabecular bone (2−12 MPa). When immersed in phosphate‐buffered saline, the crosslinked scaffolds rapidly absorbed water (∼440% of its dry weight after 2 h) and showed an elastic response at deformations up to ∼60%. Immersion of the scaffolds in a simulated body fluid resulted in the formation of a hydroxyapatite‐like surface layer within 5 days, indicating their bioactivity in vitro. The scaffolds supported the proliferation, alkaline phosphatase activity, and mineralization of osteogenic MC3T3‐E1 cells in vitro, showing their biocompatibility. Altogether, the results indicate that these gelatin−BG hybrid scaffolds with a controlled, 3D architecture of inter‐connected pores have potential for use as implants for bone regeneration. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.