bluuebunny/crossref_metadata_2025_split huggingface dataset:
Migratory Insertion of Alkenes into Metal–Oxygen and Metal–Nitrogen Bonds
Authors: Hanley Patrick S. , Hartwig John F. 
Published: July 2013

AbstractThe insertion of an unsaturated ligand into a MC or MH bond proceeds through migratory insertion, a fundamental organometallic reaction. Recent literature documents evidence of the migratory insertion of alkenes into an MO and MN bonds for alkene alkoxylation and alkene amination reactions, respectively. Herein we provide an overview of the literature and a perspective on how these recent experiments relate to classic experiments on CO and CN bond formation with alkene complexes of the late transition metals.
Quantitative analysis of organophosphorus pesticides in freshwater using an optimized firefly luciferase‐based coupled bioluminescent assay
Authors: Marques SM , da Silva JCG Esteves 
Published: July 2013

ABSTRACTIn this paper, a coupled bioluminescent assay, relying on the coupling of the enzymes acetylcholinesterase, S‐acetyl‐coenzyme A synthetase and firefly luciferase, for the detection and quantitation of organophosphorus pesticides, is presented. Using malathion as a model organophosphorus pesticide, the assay was optimized through statistical experimental design methodology, namely Plackett–Burman and central composite designs. The optimized method requires only 20 μL of sample. The linear range for the assay was 2.5–15 μM of malathion, with limits of detection and quantitation of 1.5 and 5.0 μM, respectively. This simple, fast and robust method allows samples to be analyzed at room temperature and without any pretreatment. Copyright © 2013 John Wiley & Sons, Ltd.
Elongation factor P: Function and effects on bacterial fitness
Authors: Doerfel Lili K. , Rodnina Marina V. 
Published: July 2013

ABSTRACTThe elongation phase of translation is promoted by three universal elongation factors, EF‐Tu, EF‐Ts, and EF‐G in bacteria and their homologs in archaea and eukaryotes. Recent findings demonstrate that the translation of a subset of mRNAs requires a fourth elongation factor, EF‐P in bacteria or the homologs factors a/eIF5A in other kingdoms of life. EF‐P prevents the ribosome from stalling during the synthesis of proteins containing consecutive Pro residues, such as PPG, PPP, or longer Pro clusters. The efficient and coordinated synthesis of such proteins is required for bacterial growth, motility, virulence, and stress response. EF‐P carries a unique post‐translational modification, which contributes to its catalytic proficiency. The modification enzymes, which are lacking in higher eukaryotes, provide attractive new targets for the development of new, highly specific antimicrobials. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 837–845, 2013.
A novel self‐assembling peptide with UV‐responsive properties
Authors: Wei Ran , Jin Cheng‐Cheng , Quan Jing , Nie Hua‐li , Zhu Li‐Min 
Published: July 2013

ABSTRACTA novel heptapeptide comprising Ile‐Gln‐Ser‐Pro‐His‐Phe‐Phe (IQSPHFF) identified and found to undergo self‐assembly into microparticles in solution. To understand the effects of ultraviolet (UV) irradiation on the self‐assembly process, IQSPHFF solutions were exposed to the UV light of 365 nm at room temperature. This exposure was found to have a profound effect on the morphology of the self‐assembled aggregates, converting the microparticles to nanorod shapes. Circular dichroism and FTIR studies indicated distinct structural differences in the arrangements of the peptide moieties before and after UV irradiation. However, Mass spectrum analysis and high performance liquid chromatography of the peptide molecules before and after UV irradiation demonstrated that the chemical structure of IQSPHFF was not changed. UV–visible spectroscopy and fluorescence spectroscopy studies showed that the absorption peak both increased after UV irradiation. Overall, our data show that the heptapeptide with UV‐responsive properties. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 272–278, 2014.
Effects of Sonocrystallization on the Crystal Size Distribution of Cloxacillin Benzathine Crystals
Authors: Li J. , Bao Y. , Wang J. 
Published: July 2013

AbstractThe effect of ultrasound on the reactive crystallization process of cloxacillin benzathine crystals was investigated to develop a better understanding of the characteristics of this poorly water‐soluble active pharmaceutical ingredient. Characteristics of the products generated under different experimental conditions were compared by offline Malvern Mastersizer measurements and microscopy. The ultrasonic waves applied to reactive crystallization of cloxacillin benzathine were found to be suitable in generating highly regular surface areas for crystal growth. The increased surface areas resulted in decreased average particle sizes and more uniform particles.
Host–Guest Complexation of [60]Fullerenes and Porphyrins Enabled by “Click Chemistry”
Authors: Ho Khanh‐Hy Le , Hijazi Ismail , Rivier Lucie , Gautier Christelle , Jousselme Bruno , de Miguel Gustavo , Romero‐Nieto Carlos , Guldi Dirk M. , Heinrich Benoit , Donnio Bertrand , Campidelli Stéphane 
Published: July 2013

AbstractHerein the synthesis, characterization, and organization of a first‐generation dendritic fulleropyrrolidine bearing two pending porphyrins are reported. Both the dendron and the fullerene derivatives were synthesized by CuI‐catalyzed alkyne–azide cycloaddition (CuAAC). The electron‐donor–acceptor conjugate possesses a shape that allows the formation of supramolecular complexes by encapsulation of C60 within the jaws of the two porphyrins of another molecule. The interactions between the two photoactive units (i.e., C60 and Zn–porphyrin) were confirmed by cyclic voltammetry as well as by steady‐state and time‐resolved spectroscopy. For example, a shift of about 85 mV was found for the first reduction of C60 in the electron‐donor–acceptor conjugate compared with the parent molecules, which indicates that C60 is included in the jaws of the porphyrin. The fulleropyrrolidine compound exhibits a rich polymorphism, which was corroborated by AFM and SEM. In particular, it was found to form supramolecular fibrils when deposited on substrates. The morphology of the fibrils suggests that they are formed by several rows of fullerene–porphyrin complexes.
Mannose‐Binding Geometry of Pradimicin A
Authors: Nakagawa Yu , Doi Takashi , Taketani Takara , Takegoshi K. , Igarashi Yasuhiro , Ito Yukishige 
Published: July 2013

AbstractPradimicins (PRMs) and benanomicins are the only family of non‐peptidic natural products with lectin‐like properties, that is, they recognize D‐mannopyranoside (Man) in the presence of Ca2+ ions. Coupled with their unique Man binding ability, they exhibit antifungal and anti‐HIV activities through binding to Man‐containing glycans of pathogens. Notwithstanding the great potential of PRMs as the lectin mimics and therapeutic leads, their molecular basis of Man recognition has yet to be established. Their aggregate‐forming propensity has impeded conventional interaction analysis in solution, and the analytical difficulty is exacerbated by the existence of two Man binding sites in PRMs. In this work, we investigated the geometry of the primary Man binding of PRM‐A, an original member of PRMs, by the recently developed analytical strategy using the solid aggregate composed of the 1:1 complex of PRM‐A and Man. Evaluation of intermolecular distances by solid‐state NMR spectroscopy revealed that the C2–C4 region of Man is in close contact with the primary binding site of PRM‐A, while the C1 and C6 positions of Man are relatively distant. The binding geometry was further validated by co‐precipitation experiments using deoxy‐Man derivatives, leading to the proposal that PRM‐A binds not only to terminal Man residues at the non‐reducing end of glycans, but also to internal 6‐substituted Man residues. The present study provides new insights into the molecular basis of Man recognition and glycan specificity of PRM‐A.
Understanding the Initial Decomposition Pathways of the n‐Alkane/Nitroalkane Binary Mixture
Authors: Guan Yulei , Zhang Ying , Yi Chunhai , Yang Bolun 
Published: July 2013

AbstractAddition of nitroalkanes into n‐alkanes can lower the activation barriers of free‐radical production and accelerate the decomposition of n‐alkanes at relatively low temperatures. Four initial decomposition mechanisms of the n‐butane/nitroethane binary mixture were proposed for the promoting effect and considered theoretically at the B3LYP, BB1K, BMK, MPW1K, and M06‐2X levels with MG3S basis set. Energetics above was compared to high‐level CBS‐QB3 and G4 calculations. Calculated results confirm the feasibility of the four initial decomposition pathways: (I) the CNO2 bond rupture of nitroethane to produce ethyl and ·NO2, (II) HONO elimination from nitroethane followed by decomposition to ·OH and ·NO, (III) rearrangement of nitroethane to ethyl nitrite which further dissociates into CH3CH2O· and ·NO, and (IV) direct hydrogen‐abstraction of nitroethane with n‐butane.
Syntheses, Structures and Properties of Four New Transitional Metal Complexes Based on Benzotriazole‐5‐carboxylic Acid
Authors: Li Yang , Sun Changyan , Li Wenjun , Zhou Hualei , Dong Bin 
Published: July 2013

AbstractFour new complexes, [Zn(btca)(2,2′‐bpy)] (1), [Mn(btca)(2,2′‐bpy)] (2), [Co(btca)(phen)] (3), and [Cu(btca)(phen)] (4), (H2btca=benzotriazole‐5‐carboxylic acid, 2,2′‐bpy=2,2′‐bipyridine, phen=1,10‐phenanthroline), were successfully synthesized and characterized by elemental analysis, single crystal X‐ray diffraction, and IR spectroscopy. Complexes 1–4 crystallize in the orthorhombic system with space group of Pbca and show similar 2D layers, which are interlinked to supramolecular networks by π‐π stacking interactions. Furthermore, TGA curves show that complexes 1–4 have good thermal stability. Solid‐state fluorescent property of complex 1 was also investigated at room temperature.
Iron(III) Chloride Catalyzed Oxidative Coupling Reaction of 1,2‐Diarylethylene Derivatives
Authors: Ji Derong , Su Lidan , Zhao Keqing , Wang Biqin , Hu Ping , Feng Chun , Xiang Shikai , Yang Hua , Zhang Chenggang 
Published: July 2013

AbstractA nontoxic FeCl3 catalyzed intramolecular oxidative coupling reaction was developed for mild synthesis of a series of phenanthrenes with different substituents. The method involves cross dehydrogenative coupling of a variety of 1,2‐diarylethylene derivatives with di‐tert‐butylperoxide (DTBP) as a sole oxidant at room temperature in CH2Cl2/TFA (9:1 V/V) to yield phenanthrenes in good to excellent yields.
Copper(II)‐Catalyzed Tandem Synthesis of Substituted 3‐Methyleneisoindolin‐1‐ones
Authors: Pan Jie , Xu Zhen , Zeng Runsheng , Zou Jianping 
Published: July 2013

AbstractAn efficient strategy for the synthesis of a variety of 3‐methyleneisoindolin‐1‐ones has been developed. The reaction proceeded from coupling of 2‐iodobenzamides (or 2‐bromobenzamides) and terminal alkynes via Cu(OAc)2·H2O/2,2′‐biimidazole catalyzed in DMF at 60°C and subsequent additive cyclization produced substituted 3‐methyleneisoindolin‐1‐ones in good to excellent yields.
Design and Synthesis of Tri‐substituted Chiral Pyrrolidin‐2‐one Derivatives as CCR4 Antagonists
Authors: Sun Wei , Tian Linjie , Qi Hui , Jiang Dan , Wang Ying , Li Song , Xiao Junhai , Yang Xiaohong 
Published: July 2013

AbstractA series of tri‐substituted chiral pyrrolidin‐2‐one derivatives have been designed and synthesized as CC chemokine receptor 4 (CCR4) antagonists. The structure of CCR4 was built by homology modeling. Asymmetric synthesis was applied to synthesize the R,R configuration chiral pyrrolidin‐2‐one scaffold. The stereoisomeric configurations of the compounds were identified by 2D 1H‐1H COSY spectroscopy and 1D NOESY spectroscopy. This method was more economical and convenient than traditional X‐ray single crystal diffraction. In addition, the interactions between these compounds and the N‐terminal extracellular tail of CCR4 were studied using capillary zone electrophoresis. The CCR4 chemotaxis inhibition effect was tested in CCR4‐transfected HEK293 cells. Several compounds showed potent activities as CCR4 antagonists. Among these compounds, 1c is the most active one. Its apparent binding constant of CZE experiment result is (1.569±0.11)×105 L·mol−1, and its percentage inhibition of the HEK293/CCR4 cells migration with the concentration of 1 µmol·L−1 in DMSO is 59%. And compound 1f has slightly higher affinity to N‐terminal of CCR4 according to its apparent binding constant than 1b because of the introduced ester linkage. Further studies on the mechanism of these compounds are in progress.
Highly Stereoselective and One‐Pot Synthesis of Tetra‐substituted Monofluoroalkenes with Aldehydes and Fluorobis(phenylsulfonyl)methane
Authors: Shen Xiao , Ni Chuanfa , Hu Jinbo 
Published: July 2013

AbstractA highly stereoselective synthesis of tetrasubstituted monofluoroalkenes with aldehydes and fluorobis(phenylsulfonyl)methane (FBSM) in one pot has been developed. The reaction was amenable to para‐ and meta‐substituted aryl aldehydes, 2‐naphthaldehyde, and cinnamaldehyde, giving phenylsulfonyl‐substituted monofluoroalkenes in 40%–86% yields with 98/2–99/1 Z/E ratios. The presence of the sulfonyl group enables the further transformation of the products into more useful monofluoroalkenes.
Regioselective Synthesis of 2,6‐Dimethyl‐3,5‐bis[(3‐aryl‐5‐trifluoromethyl)‐isoxazol‐4‐carbonyl]‐pyridine Derivatives
Authors: Yang Yindi , Zhang Min , Zhu Yiwen , Zhang Li , Xie Qiqiang , Song Liping , Deng Hongmei 
Published: July 2013

AbstractEthyl 4,4,4‐trifluoro‐3‐oxo‐butyrate reacted with 2,6‐dimethyl‐3,5‐diacetyl‐pyridine 1 in the presence of NaOC2H5 at 0°C to give 2,6‐dimethyl‐3,5‐bis(4,4,4‐trifluoro‐1,3‐oxo‐butyl)‐pyridine (2a) in good yield. Cyclization reaction of 2a and aryl imidoyl chlorides 5a–5i, obtained from chlorination of aryl oximes with N‐chlorosuccimide, afforded 2,6‐dimethyl‐3,5‐bis[(3‐aryl‐5‐trifluoromethyl)‐isoxazol‐4‐carbonyl]‐pyridine derivatives 6a–6i.
Chemical, Pharmacological, and in vitro Metabolic Stability Studies on Enantiomerically Pure RC‐33 Compounds: Promising Neuroprotective Agents Acting as σ1 Receptor Agonists
Authors: Rossi Daniela , Pedrali Alice , Gaggeri Raffaella , Marra Annamaria , Pignataro Luca , Laurini Erik , Dal Col Valentina , Fermeglia Maurizio , Pricl Sabrina , Schepmann Dirk , Wünsch Bernhard , Peviani Marco , Curti Daniela , Collina Simona 
Published: July 2013

AbstractOur recent research efforts identified racemic RC‐33 as a potent and metabolically stable σ1 receptor agonist. Herein we describe the isolation of pure RC‐33 enantiomers by chiral chromatography, assignment of their absolute configuration, and in vitro biological studies in order to address the role of chirality in the biological activity of these compounds and their metabolic processing. The binding of enantiopure RC‐33 to the σ1 receptor was also investigated in silico by molecular dynamics simulations. Both RC‐33 enantiomers showed similar affinities for the σ1 receptor and appeared to be almost equally effective as σ1 receptor agonists. However, the R‐configured enantiomer showed higher in vitro hepatic metabolic stability in the presence of NADPH than the S enantiomer. Overall, the results presented herein led us to select (R)‐RC‐33 as the optimal candidate for further in vivo studies in an animal model of amyotrophic lateral sclerosis.
Caspofungin exposure‐response relationships in adult patients with mucosal or invasive candidiasis
Authors: Comisar Wendy , Sun Peng , Li Susan , Sable Carole , Schwartz Michael , Bi Sheng , Chow Joseph , Ngai Angela , Winchell Gregory , Kartsonis Nicholas , Stone Julie 
Published: July 2013

AbstractCaspofungin is an echinocandin antifungal agent administered once daily as an intravenous infusion. Relationships between caspofungin exposure and clinical efficacy and safety were investigated. End‐of‐infusion (CEOI) and trough (C24 hours) concentrations were obtained in 218 patients with mucosal (i.e., esophageal and/or oropharyngeal) candidiasis (MC) receiving caspofungin 35, 50, or 70 mg/day and 278 patients with invasive candidiasis (IC) receiving 50, 100, or 150 mg/day. Area under the plasma concentration–time curve (AUC0–24 hours) was obtained in a subset of MC patients (n = 99). Odds ratios were estimated for the association between log‐transformed PK and efficacy response and the occurrence of common adverse events. No pharmacokinetic or hybrid parameter (ratio of AUC:MIC, CEOI:MIC, C24 hours:MIC) was significantly correlated with overall treatment outcome in either MC or IC, although this patient population may exhibit confounding factors which masked a potential pharmacokinetic/pharmacodynamic relationship. An exploratory evaluation of MC identified significant pharmacokinetic correlations with endoscopic response, but not symptom response. Statistically significant associations were identified for IC patients with C. parapsilosis infections. Occurrence of clinical adverse events and/or laboratory abnormalities did not appear to be increased by higher caspofungin plasma concentrations. Caspofungin concentrations achieved with 50 mg/day are generally within the therapeutic window for the treatment of candidiasis.
Ultrafast Dynamics of meso‐Tetraphenylmetalloporphyrins: The Role of Dark States
Authors: Liang Yu , Bradler Maximilian , Klinger Melanie , Schalk Oliver , Balaban Mihaela Carmen , Balaban Teodor Silviu , Riedle Eberhard , Unterreiner Andreas‐Neil 
Published: July 2013

AbstractStudying the relaxation pathways of porphyrins and related structures upon light absorption is crucial to understand the fundamental processes of light harvesting in biosystems and many applications. Herein, we show by means of transient absorption studies, following Q‐ and Soret‐band excitation, and ab initio calculations on meso‐tetraphenylporphyrinato magnesium(II) (MgTPP) and meso‐tetraphenylporphyrinato cadmium(II) (CdTPP) that electronic relaxation following Soret‐band excitation of porphyrins with a heavy central atom is mediated by a hitherto disregarded dark state. This accounts for an increased rate of internal conversion. The dark state originates from an orbital localized at the central nitrogen atoms and its energy continuously decreases along the series from magnesium to zinc to cadmium to below 2.75 eV for CdTPP dissolved in tetrahydrofuran. Furthermore, we are able to directly trace fast intersystem crossing in the cadmium derivative, which takes place within (110±20) ps.
Linear circuits: a measurement‐based approach
Authors: Mohsenizadeh Navid , Nounou Hazem , Nounou Mohamed , Datta Aniruddha , Bhattacharyya Shankar P. 
Published: July 2013

SummaryThis paper proposes a new measurement‐based approach that can solve synthesis problems in unknown linear circuits. The method makes use of a small number of measurements to determine the functional dependency of any circuit signal or variable on any set of design variables. Once the functional dependency is obtained, the design requirements can be applied to find the design parameter values. The results are described for linear direct current and alternating current circuits. Copyright © 2013 John Wiley & Sons, Ltd.
Neuropsychological functioning in adolescents with anorexia nervosa before and after cognitive remediation therapy: A feasibility trial
Authors: Dahlgren Camilla Lindvall , Lask Bryan , Landrø Nils Inge , Rø Øyvind 
Published: July 2013

ABSTRACTObjectiveTo investigate neuropsychological functioning in adolescents with anorexia nervosa (AN) before and after receiving cognitive remediation therapy (CRT).MethodTwenty young females with AN participated in an individually‐delivered CRT treatment program. Neuropsychological and psychiatric assessments were administered before and after treatment. Weight, depression, anxiety, duration of illness, and level of eating disorder psychopathology were considered as covariates in statistical analyses.ResultsSignificant changes in weight, depression, visio‐spatial memory, perceptual disembedding abilities, and verbal fluency were observed. Changes in weight had a significant effect on improvements in visuo‐spatial memory and verbal fluency. Results also revealed a significant effect of depressive symptoms on perceptual disembedding abilities.DiscussionThe results suggest improvements on a number of neuropsychological functions during the course of CRT. Future studies should explore the use of additional assessment instruments, and include control groups to assess the effectiveness of the intervention. © 2013 Wiley Periodicals, Inc. (Int J Eat Disord 2013; 46:576–581)
Pyridinediimine Iron Dicarbonyl Complexes with Pendant Lewis Bases and Lewis Acids Located in the Secondary Coordination Sphere
Authors: Thammavongsy Zachary , LeDoux Micah E. , Breuhaus‐Alvarez Andrew G. , Seda Takele , Zakharov Lev N. , Gilbertson John D. 
Published: July 2013

AbstractA series of asymmetric iron(II) dichloride and dicarbonyl pyridinediimine (PDI) complexes that contain either pendant Lewis bases or Lewis acids located in the secondary coordination sphere were synthesized. These complexes are important intermediates in the reduction scheme of the small molecule CO2 on iron(II). The electrochemistry of the direduced FePDI(CO)2 complexes was evaluated for the 2‐electron oxidation from the reduced‐ligand to the neutral‐ligand species. The complexes with either pendant Lewis bases or Lewis acids located in the secondary coordination sphere displayed reduction potentials for CO release that span over 300 mV.
Efficient and Rapid Synthesis of Chlorido‐Bridged Half‐Sandwich Complexes of Ruthenium, Rhodium, and Iridium by Microwave Heating
Authors: Tönnemann Justus , Risse Julie , Grote Zacharias , Scopelliti Rosario , Severin Kay 
Published: July 2013

AbstractThe dinuclear complexes [(p‐cymene)RuCl2]2 and [(cyclopentadienyl)MCl2]2 (M = Ru, Rh, Ir) are important starting materials in organometallic chemistry. The standard synthesis of these complexes involves heating of an alcoholic solution of RuIII, RhIII, or IrIII salts with precursors of the π‐ligands for several hours under reflux. Microwave heating allows these complexes to be obtained within a few minutes without compromising the yields. Furthermore, the microwave‐assisted syntheses require less solvent and, in some cases, lower amounts of ligand precursors.