bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanotube surface functionalization effects in blended multiwalled carbon nanotube/PVDF composites
Authors: O'Bryan G. , Yang E. L. , Zifer T. , Wally K. , Skinner J. L. , Vance A. L. 
Published: November 2010

AbstractA mixed fill system of multiwalled carbon nanotubes (MWCNT) and hydroxylated MWCNT (HO‐MWCNT) in a poly(vinylidene fluoride) (PVDF) matrix was investigated to improve nanotube dispersion and enhance electrical percolation for the bulk nanocomposites. Nonfunctionalized MWCNT were blended at various concentrations into dimethylformamide solutions containing PVDF with 0, 5, or 10 wt % HO‐MWCNT. Composite samples prepared from these solutions were examined by four‐point probe resistivity measurements. The percolation threshold decreased from 0.49 wt % MWCNT in binary MWCNT/PVDF composites to 0.25 wt % for ternary composites containing MWCNT/HO‐MWCNT/PVDF, with either 5 or 10 wt % HO‐MWCNT. In the case of the ternary composite with 10 wt % HO‐MWCNT, the lowest fill percent of MWCNT (0.25 wt %) measured a conductivity that was three orders of magnitude higher than the binary MWCNT/PVDF composite containing twice the concentration of MWCNT (0.5 wt %). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Total Synthesis and Bioactivities of Two Proposed Structures of Maresin
Authors: Sasaki Kenji , Urabe Daisuke , Arai Hiroyuki , Arita Makoto , Inoue Masayuki 
Published: November 2010

AbstractMaresin is a potent anti‐inflammatory lipid mediator derived from docosahexaenoic acid (DHA). A highly convergent total synthesis of two proposed structures of C7‐epimeric maresins from the four known fragments was achieved in 17 steps. The three key coupling reactions were the BF3‐mediated alkyne attack on the epoxide, chiral titanium complex‐promoted enantioselective alkyne addition to the aldehyde, and a Julia–Kocienski olefination. The two synthesized diastereomers were found to be comparably active in blocking neutrophil infiltration in the acute peritonitis model.
The Axial Ligand Effect on Aliphatic and Aromatic Hydroxylation by Non‐heme Iron(IV)–oxo Biomimetic Complexes
Authors: de Visser Sam P. , Latifi Reza , Tahsini Laleh , Nam Wonwoo 
Published: November 2010

AbstractIron(IV)‐oxo heme cation radicals are active species in enzymes and biomimetic model complexes. They are potent oxidants in oxygen atom transfer reactions, but the reactivity is strongly dependent on the ligand system of the iron(IV)–oxo group and in particular the nature of the ligand trans to the oxo group (the axial ligand). To find out what effect the axial ligand has on the reactivity of non‐heme iron(IV)–oxo species, we have performed a series of density functional theory (DFT) calculations on aliphatic and aromatic hydroxylation reactions by using [FeIVO(TMC)(L)]n+ (TMC=1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane, and L=acetonitrile or chloride). The studies show that the regioselectivity of aliphatic over aromatic hydroxylation is preferred. The studies are in good agreement with experimental product distributions. Moreover, the system with the acetonitrile axial ligand is orders of magnitude more reactive than that with a chloride axial ligand. We have analyzed our results and we have shown that the metal–ligand interactions influence the orbital energies and as a consequence also the electron affinities and hydrogen atom abstraction abilities. Thermodynamic cycles explain the regioselectivity preferences.
Nickel(0) Complexes with Fluorinated Alkyne Ligands and their Reactivity towards Semihydrogenation and Hydrodefluorination with Water
Authors: Barrios‐Francisco Rigoberto , Benítez‐Páez Tania , Flores‐Alamo Marcos , Arévalo Alma , García Juventino J. 
Published: November 2010

AbstractThe current work describes the synthesis and full characterization of zerovalent nickel complexes of the type [(dippe)Ni(η2‐C,C‐Fn‐alkyne)] (dippe=1,2‐bis(di‐isopropylphosphino‐ethane), Fn‐alkyne=fluorinated aromatic alkyne, n=1, 3, 5; 3a, 3b, 3c) and [{(dippe)Ni}2(μ2‐C,C‐Fn‐alkyne)] (4). Reactions with complexes 3a, 3b, 3c, and water as the hydrogen source, yield selective semihydrogenation of the bound alkyne to the corresponding alkene, accompanied by partial hydrodefluorination of the aromatic ring. Different alkynes were tested; on using the alkyne with five fluorine atoms over the aromatic ring, partial defluorination was achieved under the mildest reaction conditions, followed in reactivity by the alkyne with three fluorine atoms. The alkyne with only one fluorine atom was barely defluorinated. The use of triethylsilane as a sacrificial hydride source resulted in an overall increase in reactivity towards defluorination.
Electrophilic Addition Reaction of Ethene with Hydrogen Chloride on Cold Molecular Films: Evidence of Ethyl Cationic Intermediate
Authors: Lee Poong‐Ryul , Lee Chang‐Woo , Kim Joon‐Ki , Moon Eui‐Seong , Kang Heon 
Published: November 2010

AbstractWe studied the initial‐stage mechanism of the electrophilic addition reaction of ethene with HCl by examining the interactions between ethene and HCl on water‐ice and frozen molecular films at temperatures of 80–140 K. Cs+ reactive ion scattering (RIS) and low‐energy sputtering (LES) techniques were used to probe the reaction intermediates that were kinetically trapped on the surface, in conjunction with temperature‐programmed desorption (TPD) mass spectrometry to monitor the desorbing species. The reaction initially produced the π complex of HCl and ethene at temperatures below about 93 K and an “ethyl cationic species” at temperatures below about 100 K. The ethyl cationic species was formed via direct proton transfer from the HCl molecule to ethene with the assistance of water solvation, rather than via the interaction of hydronium ions and ethene. At high temperatures, this species dissociated into ethene and hydronium and chloride ions. The reaction did not, however, complete the final transition state on the ice surface to produce ethyl chloride. The observation gives evidence that the electrophilic addition reaction of ethene occurs through an ethyl‐like intermediate with an ionic character.
Adaptive sliding mode observer‐based synchronization for uncertain chaotic systems
Authors: Pai Ming‐Chang 
Published: November 2010

AbstractThis paper investigates the synchronization problem for a class of uncertain chaotic systems. Only partial information of the system states is known. An adaptive sliding mode observer‐based slave system is designed to synchronize a given chaotic master system with unknown parameters and external disturbances. Based on the Lyapunov stability theorem, the global synchronization between the master and slave systems is ensured. Furthermore, the structure of the slave system is simple and the proposed adaptive sliding mode observer‐based synchronization scheme can be implemented without requiring a priori knowledge of upper bounds on the norm of the uncertainties and external disturbances. Simulation results demonstrate the effectiveness and robustness of the proposed scheme.Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Accounting for critical evidence while being precise and avoiding the strategy selection problem in a parallel constraint satisfaction approach: A reply to Marewski (2010)
Authors: Glöckner Andreas , Betsch Tilmann 
Published: November 2010

AbstractIn Glöckner, Betsch and Schindler (2010) we observed predecisional information distortions (coherence shifts) in probabilistic inferences that indicate bidirectional reasoning. In response to Marewski's (2010) critique, we explain why coherence shifts cannot be explained by currently specified fast and frugal heuristics (FFH). In contrast, parallel constraint satisfaction (PCS) models can easily account for such effects. We show that the PCS model used in the target paper is sufficiently well specified with respect to predicting the observed effects and demonstrate that it circumvents the problem of strategy selection by using a single‐strategy approach. Taking a broader perspective, we argue that empirical and theoretical challenges to the FFH approach have become so substantial that a mere extension of the suggested toolbox might not sufficiently solve the problem. We suggest that further theoretical work in the field of judgment and decision making should be more responsive to well‐established findings and insights from other fields of cognition such as memory and perception. Copyright © 2009 John Wiley & Sons, Ltd.
Randomized clinical trial of routine on-table cholangiography during laparoscopic cholecystectomy
Authors: Khan O A , Balaji S , Branagan G , Bennett D H , Davies N 
Published: November 2010

Abstract

Background
A randomized clinical trial was undertaken to assess the utility of routine on-table cholangiography (OTC) during laparoscopic cholecystectomy for gallstone disease.

Methods
Some 190 patients with a history of biliary colic or cholecystitis and a low predictive risk for choledocholithiasis were randomized to undergo elective laparoscopic cholecystectomy alone (99 patients) or elective laparoscopic cholecystectomy with OTC (91). Intraoperative findings and postoperative outcomes for the two groups were compared. The primary outcome measure was the incidence of common bile duct (CBD) stones.

Results
Of the patients undergoing OTC, ten had abnormal cholangiograms; three had CBD stones and seven had abnormalities without stones. OTC was associated with a significantly longer mean(s.e.m.) operating time (66(2) versus 54(3) min; P &lt; 0·001), but there was no association between performance of OTC and postoperative morbidity. During a 1-year follow-up, no patient in the OTC group re-presented to hospital with recurrent biliary symptoms. In contrast, four of the patients allocated to surgery alone re-presented with symptoms suggestive of CBD obstruction; all settled with conservative treatment and the difference in readmission rate was not significant (P = 0·122).

Conclusion
Routine cholangiography in patients with a low risk for CBD stones does not seem justified from the results of this trial. Registration number: NCT00806780 (http://www.clinicaltrials.gov).
Laparoscopy-assisted gastrectomy in patients with previous endoscopic resection for early gastric cancer
Authors: Jiang X , Hiki N , Yoshiba H , Nunobe S , Kumagai K , Sano T , Yamaguchi T 
Published: November 2010

Abstract

Background
Some patients undergoing endoscopic resection for early gastric cancer need further surgical treatment to achieve cure. However, the influence of endoscopic resection on subsequent laparoscopy-assisted gastrectomy (LAG) remains unclear.

Methods
A total of 711 patients who underwent LAG were analysed retrospectively; 111 patients had undergone endoscopic resection previously and the remaining 600 had no history of endoscopic resection. Patient characteristics, operative and postoperative outcomes were compared between the two groups. Risk factors associated with postoperative complications were analysed.

Results
Duration of operation and blood loss were comparable between the two groups. Patients who had undergone endoscopic resection had fewer dissected lymph nodes and a lower rate of preservation of the coeliac branch of the vagus nerve, especially those who had LAG within 2 months after endoscopic resection. Early postoperative outcomes, including complications, gastrointestinal recovery and length of postoperative hospital stay, were not significantly different between the two groups. Previous endoscopic resection was not a risk factor for postoperative complications.

Conclusion
LAG can be performed safely even after endoscopic resection. Endoscopic resection might increase the difficulty of subsequent LAG, including lymph node dissection and preservation of the coeliac branch of the vagus nerve; however, it has little influence on early postoperative outcome.
KAT(ching) Metabolism by the Tail: Insight into the Links between Lysine Acetyltransferases and Metabolism
Authors: Albaugh Brittany N. , Arnold Kevin M. , Denu John M. 
Published: November 2010

AbstractPost‐translational modifications of histones elicit structural and functional changes within chromatin that regulate various epigenetic processes. Epigenetic mechanisms rely on enzymes whose activities are driven by coenzymes and metabolites from intermediary metabolism. Lysine acetyltransferases (KATs) catalyze the transfer of acetyl groups from acetyl‐CoA to epsilon amino groups. Utilization of this critical metabolite suggests these enzymes are modulated by the metabolic status of the cell. This review highlights studies linking KATs to metabolism. We cover newly identified acyl modifications (propionylation and butyrylation), discuss the control of KAT activity by cellular acetyl‐CoA levels, and provide insights into how acetylation regulates metabolic proteins. We conclude with a discussion of the current approaches to identifying novel KATs and their metabolic substrates.
Incorporation of 2′‐Deoxy‐2′‐isonucleoside 5′‐Triphosphates (iNTPs) into DNA by A‐ and B‐Family DNA Polymerases with Different Recognition Mechanisms
Authors: Ogino Takaaki , Sato Kousuke , Matsuda Akira 
Published: November 2010

AbstractRecently, α‐L‐threofuranosyl nucleoside 3′‐triphosphates (tNTPs) have been reported to be incorporated into DNA by DNA polymerases. Isonucleosides especially the 2′‐deoxy‐2′‐isonucleosides, would be considered regioisomers of α‐L‐threofuranosyl nucleosides. Therefore, we investigated the synthesis of 2′‐deoxy‐2′‐isonucleoside 5′‐triphosphates (iNTPs) having the four natural nucleobases and their incorporation into primer–template duplexes consisting of oligonucleotides containing natural 2′‐deoxyribonucleosides and 2′‐deoxy‐2′‐isonucleosides by using primer‐extension reactions. We found that Klenow fragment (exo‐; an A‐family DNA polymerase) has strict recognition of the shape of nucleoside 5′‐triphosphates and Therminator (a B‐family DNA polymerase) has strict recognition of the shape of primer–template complexes, especially two base pairs upstream of the primer 3′ terminus.
Design and Synthesis of Antifreeze Glycoproteins and Mimics
Authors: Garner James , Harding Margaret M. 
Published: November 2010

AbstractAntifreeze glycoproteins are an important class of biological antifreezes that have potential applications in many areas of medicine, agriculture and industry in which ice crystal growth is damaging. While the synthesis of antifreeze glycoproteins as pure glycoforms has recently been achieved by using ligation and polymerisation strategies, the routine production of large quantities of pure glycoforms remains challenging. A range of C‐linked analogues that are readily produced by solid‐phase synthesis have delivered novel compounds that are not biological antifreezes, but are potent, non‐cytotoxic, ice‐recrystallisation inhibitors. Structure–activity studies, the identification of cyclic antifreeze glycoproteins and conformational studies have provided further insight into the requirements for antifreeze activity. These results, coupled with significant advances in approaches to the routine synthesis of different glycoproteins and mimics, present opportunities for the design and synthesis of novel ice‐growth‐inhibiting and antifreeze compounds.
Analysis of Metal Ion Dependence in glmS Ribozyme Self‐Cleavage and Coenzyme Binding
Authors: Klawuhn Kevin , Jansen Joshua A. , Souchek Joshua , Soukup Garrett A. , Soukup Juliane K. 
Published: November 2010

AbstractThe bacterial glmS ribozyme is mechanistically unique among both riboswitches and RNA catalysts. Its self‐cleavage activity is the basis of riboswitch regulation of glucosamine‐6‐phosphate (GlcN6P) production, and catalysis requires GlcN6P as a coenzyme. Previous work has shown that the coenzyme amine of GlcN6P is essential for glmS ribozyme self‐cleavage, as is its protonation state. Metal ions are also essential within the glmS ribozyme core for both structure and function of the ribozyme. Although metal ions do not directly promote catalysis, we show that metal ion identity and the varying physicochemical properties of metal ions have an impact on the rate of glmS ribozyme self‐cleavage. Specifically, these studies demonstrate that metal ion identity influences the overall apparent pKa of ribozyme self‐cleavage, and metal ion binding largely reflects phosphate oxygen affinity. Results suggest that metal ions take alternative roles in supporting the mechanism of catalysis.
Liquid Holdup in a Pilot‐Scale Turbulent Contact Absorber – An Experimental and Comparative Study
Authors: Haq A. , Inayat M. H. , Zaman M. , Chughtai I. R. 
Published: November 2010

AbstractLiquid holdup in a turbulent contact absorber was determined experimentally. Experiments were performed in a 44.7 cm diameter Perspex column. Hollow spherical high‐density polyethylene balls were used as packing. The effect of liquid and gas velocities, static bed height, diameter and density of packing on liquid holdup was investigated for the range of gas velocities greater than minimum fluidization velocities. Also, the effect of gas and liquid distributors on liquid holdup was studied. Correlations for liquid holdup were developed and compared with those in the literature. It was observed that liquid holdup increased with the increase in liquid velocity, packing density, and the decrease in static bed height. Liquid holdup also increased with gas velocity when the gas distributor section was included, while no effect was observed for the bed. Lack of information on the contribution of liquid and gas distributors seems to be the logical explanation for the wide variation in data reported in the literature.
Partition Coefficients of Alkyl Parabens and Ibuprofen in Micellar Systems
Authors: Wille S. , Mokrushina L. , Smirnova I. , Arlt W. 
Published: November 2010

AbstractThe partitioning of alkyl parabens and ibuprofen in aqueous solutions of nonionic and ionic surfactants is studied experimentally and via a priori predictions using the COSMO‐RS model. The effects of organic (Bu4NBr) and inorganic (NaCl) electrolytes are examined. Addition of NaCl results in a slight increase in the partition coefficients of parabens in solutions of octylphenolpoly(ethyleneglycolether) and a more pronounced increase in the sodium dodecyl sulfate (SDS) system. The partition coefficients of ibuprofen increase on addition of NaCl to aqueous solutions of SDS and decrease if Bu4NBr is added to dodecyl trimethyl ammonium bromide (DTAB) solutions. Good agreement between experimental and calculated data shows a high potential of COSMO‐RS in the prediction of micelle/water partition coefficients in the presence of electrolytes and makes it a valuable tool in drug and drug‐carrier design as well as in optimizing micellar reactions or micelle‐enhanced separation processes.
On the Significance of the Anchoring Group in the Design of Antenna Materials Based on Phthalocyanine Stopcocks and Zeolite L
Authors: López‐Duarte Ismael , Le‐Quyenh Dieu  , Dolamic Igor , Martínez‐Díaz M. Victoria , Torres Tomás , Calzaferri Gion , Brühwiler Dominik 
Published: November 2010

AbstractThe synthesis of stopcocks based on zinc phthalocyanine for selective adsorption at the channel entrances of zeolite L is reported. The introduction of either an inert SiMe3 moiety, an imidazolium cation or a reactive isothiocyanate (NCS) group allows attachment to the channel entrances of zeolite L through van der Waals interactions, electrostatic interactions, or covalent binding, respectively. Stopcocks that rely on van‐der‐Waals‐driven adsorption require careful selection of the solvent used for the deposition onto the zeolite surface to avoid a nonspecific distribution of the molecules. Regarding the design of photonic antenna systems, a stopcock with a cationic tail was found to be the most convenient, based on the observation that efficient energy transfer from molecules located in the zeolite nanochannels is more readily obtained than in the other cases.
Brønsted Acid Catalyzed Cyclization of Hydroxylated Enynes: A Concise Synthesis of Five‐Membered Heterocycles
Authors: Ji Ke‐Gong , Chen Jin , Zhu Hai‐Tao , Yang Fang , Shaukat Ali , Liang Yong‐Min 
Published: November 2010

AbstractA mild and direct pathway for the formation of five‐membered heterocyclic compounds from hydroxylated enynes has been developed. In this reaction, hydroxylated enynes were selectively transformed into five‐membered heterocyclic compounds 2, with an allene moiety at the 3‐position, in the presence of F3CSO3H (0.1 mol %). When R1, R2=Ph, diphenylvinyl‐2,3‐dihydro‐1H‐pyrrole (2 y) was obtained. With HSbF6 (5 mol %) as the catalyst, polycyclic skeletons 3 and 4 with adjacent stereocenters were obtained. When R1=H and R2=styrene, 1,3‐dienyl‐2,5‐dihydro‐1H‐pyrrole (6 as) was formed. This Brønsted acid catalyzed domino process involves the formation of an allene carbocation intermediate, which can be readily trapped by olefins to give various novel five‐membered heterocyclic skeletons.
Aromatic and Aliphatic CH Hydrogen Bonds Fight for Chloride while Competing Alongside Ion Pairing within Triazolophanes
Authors: Hua Yuran , Ramabhadran Raghunath O. , Uduehi Esther O. , Karty Jonathan A. , Raghavachari Krishnan , Flood Amar H. 
Published: November 2010

AbstractTriazolophanes are used as the venue to compete an aliphatic propylene CH hydrogen‐bond donor against an aromatic phenylene one. Longer aliphatic CH⋅⋅⋅Cl− hydrogen bonds were calculated from the location of the chloride within the propylene‐based triazolophane. The gas‐phase energetics of chloride binding (ΔGbind, ΔHbind, ΔSbind) and the configurational entropy (ΔSconfig) were computed by taking all low‐energy conformations into account. Comparison between the phenylene‐ and propylene‐based triazolophanes shows the computed gas‐phase free energy of binding decreased from ΔGbind=−194 to −182 kJ mol−1, respectively, with a modest enthalpy–entropy compensation. These differences were investigated experimentally. An 1H NMR spectroscopy study on the structure of the propylene triazolophane’s 1:1 chloride complex is consistent with a weaker propylene CH hydrogen bond. To quantify the affinity differences between the two triazolophanes in dichloromethane, it was critical to obtain an accurate binding model. Four equilibria were identified. In addition to 1:1 complexation and 2:1 sandwich formation, ion pairing of the tetrabutylammonium chloride salt (TBA+⋅Cl−) and cation pairing of TBA+ with the 1:1 triazolophane–chloride complex were observed and quantified. Each complex was independently verified by ESI‐MS or diffusion NMR spectroscopy. With ion pairing deconvoluted from the chloride–receptor binding, equilibrium constants were determined by using 1H NMR (500 μM) and UV/Vis (50 μM) spectroscopy titrations. The stabilities of the 1:1 complexes for the phenylene and propylene triazolophanes did not differ within experimental error, ΔG=(−38±2) and (−39±1) kJ mol−1, respectively, as verified by an NMR spectroscopy competition experiment. Thus, the aliphatic CH donor only revealed its weaker character when competing with aromatic CH donors within the propylene‐based triazolophane.
ChemInform Abstract: Fabrication of Highly Ordered Porous Nickel Phosphide Film and Its Electrochemical Performances Toward Lithium Storage.
Authors: Xiang J. Y. , Wang X. L. , Xia X. H. , Zhong J. , Tu J. P. 
Published: November 2010

AbstractHighly ordered porous Ni3P films are electrodeposited through a self‐assembled monodisperse polystyrene sphere template on a Cu substrate followed by heating the as‐prepared films at 500 °C for 1 h under Ar flow.
ChemInform Abstract: Enantioselective Aldol Reaction Using Recyclable Montmorillonite‐Entrapped N‐(2‐Thiophenesulfonyl)prolinamide.
Authors: Hara Noriyuki , Nakamura Shuichi , Shibata Norio , Toru Takeshi 
Published: November 2010

AbstractThienylsulfonylprolinamide (TSPA) immobilized on montmorillonite represents an efficient and recyclable organocatalyst for asymmetric aldol reactions.