bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cooperative Hydrogen Bonding in Glyco–Oligoamides: DNA Minor Groove Binders in Aqueous Media
Authors: Blázquez‐Sánchez M. Teresa , Marcelo Filipa , Fernández‐Alonso M. Carmen , Poveda Ana , Jiménez‐Barbero Jesús , Vicent Cristina 
Published: October 2014

AbstractA strategy to create cooperative hydrogen‐bonding centers by using strong and directional intramolecular hydrogen‐bonding motifs that can survive in aqueous media is presented. In particular, glyco–oligoamides, a family of DNA minor groove binders, with cooperative and non‐cooperative hydrogen‐bonding donor centers in the carbohydrate residues have been designed, synthesized, and studied by means of NMR spectroscopy and molecular modeling methods. Indeed, two different sugar moieties, namely, β‐D‐Man‐Py‐γ‐Py‐Ind (1; Ind=indole, Man=mannose, Py=pyrrole) and β‐D‐Tal‐Py‐γ‐Py‐Ind (2; Tal=talose), were chosen according to our design. These sugar molecules should present one‐ or two‐directional intramolecular hydrogen bonds. The challenge has been to study the conformation of the glyco–oligoamides at low temperature in physiological media by detecting the exchangeable protons (amide NH and OH resonances) by means of NMR spectroscopic analysis. In addition, two more glyco–oligoamides with non‐cooperative hydrogen‐bonding centers, that is, β‐D‐Glc‐Py‐γ‐Py‐Ind (3; Glc=glucose), β‐D‐Gal‐Py‐γ‐Py‐Ind (4; Gal=galactose), and the model compounds β‐D‐Man‐Py‐NHAc (5) and β‐D‐Tal‐Py‐NHAc (6) were synthesized and studied for comparison. We have demonstrated the existence of directional intramolecular hydrogen bonds in 1 and 2 in aqueous media. The unexpected differences in terms of stabilization of the intramolecular hydrogen bonds in 1 and 2 relative to 5 and 6 promoted us to evaluate the influence of CH—π interactions on the establishment of intramolecular hydrogen bonds by using computational methods. Initial binding studies of 1 and 2 with calf‐thymus DNA and poly(dA‐dT)2 by NMR spectroscopic analysis and molecular dynamics simulations were also carried out. Both new sugar–oligoamides are bound in the minor groove of DNA, thus keeping a stable hairpin structure, as in the free state, in which both intramolecular hydrogen‐bonding and CH—π interactions are present.
Square‐Planar Ruthenium(II) Complexes: Control of Spin State by Pincer Ligand Functionalization
Authors: Askevold Bjorn , Khusniyarov Marat M. , Kroener Wolfgang , Gieb Klaus , Müller Paul , Herdtweck Eberhardt , Heinemann Frank W. , Diefenbach Martin , Holthausen Max C. , Vieru Veacheslav , Chibotaru Liviu F. , Schneider Sven 
Published: October 2014

AbstractFunctionalization of the PNP pincer ligand backbone allows for a comparison of the dialkyl amido, vinyl alkyl amido, and divinyl amido ruthenium(II) pincer complex series [RuCl{N(CH2CH2PtBu2)2}], [RuCl{N(CHCHPtBu2)(CH2CH2PtBu2)}], and [RuCl{N(CHCHPtBu2)2}], in which the ruthenium(II) ions are in the extremely rare square‐planar coordination geometry. Whereas the dialkylamido complex adopts an electronic singlet (S=0) ground state and energetically low‐lying triplet (S=1) state, the vinyl alkyl amido and the divinyl amido complexes exhibit unusual triplet (S=1) ground states as confirmed by experimental and computational examination. However, essentially non‐magnetic ground states arise for the two intermediate‐spin complexes owing to unusually large zero‐field splitting (D>+200 cm−1). The change in ground state electronic configuration is attributed to tailored pincer ligand‐to‐metal π‐donation within the PNP ligand series.
Enantioselective Divergent Synthesis of (−)‐cis‐α‐ and (−)‐cis‐γ‐Irone by Using Wilkinson’s Catalyst
Authors: Bugoni Serena , Boccato Debora , Porta Alessio , Zanoni Giuseppe , Vidari Giovanni 
Published: October 2014

AbstractA simple, efficient synthesis is reported for (−)‐cis‐α‐ and (−)‐cis‐γ‐irone, two precious constituents of iris oils, in ≥99 % diastereomeric and enantioselective ratios. The two routes diverge from a common intermediate prepared from (−)‐epoxygeraniol. Of general interest in this approach is the installation of the enone moiety of irones through a NHCAuI‐catalyzed Meyer–Schuster‐like rearrangement of a propargylic benzoate and the use of Wilkinson’s catalyst for the stereoselective hydrogenation of a prostereogenic exocyclic double bond to secure the critical cis stereochemistry of the alkyl groups at C2 and C6 of the irones. The stereochemical aspects of this reaction are rationally supported by DFT calculation of the conformers of the substrates undergoing the hydrogenation and by a modeling study of the geometry of the rhodium η2 complexes involved in the diastereodifferentiation of the double bond faces. Thus, computational investigation of the η2 intermediates formed in the catalytic cycle of prostereogenic alkene hydrogenation by using Wilkinson’s catalyst could be highly predictive of the stereochemistry of the products.
ChemInform Abstract: Superbase/Cellulose: An Environmentally Benign Catalyst for Chemical Fixation of Carbon Dioxide into Cyclic Carbonates.
Authors: Sun Jian , Cheng Weiguo , Yang Zifeng , Wang Jinquan , Xu Tingting , Xin Jiayu , Zhang Suojiang 
Published: October 2014

AbstractAn environmentally benign catalytic system consisting of DBU and cellulose is developed for chemical fixation of CO2 with epoxides under metal‐free and halide‐free conditions.
Resampling calibrated adjusted empirical likelihood
Authors: WANG Lei , CHEN Jiahua , PU Xiaolong 
Published: October 2014

AbstractEmpirical‐likelihood‐based inference for parameters defined by the general estimating equations of Qin & Lawless (1994) remains an active research topic. When the sample size is small and/or the dimension of the accompanying estimating equations is high, the resulting confidence regions often have a lower than nominal coverage probability. In addition, the empirical likelihood can be hindered by an empty set problem. The adjusted empirical likelihood (AEL) tackles both problems simultaneously. However, the AEL confidence region with high‐order precision relies on accurate estimation of the required level of adjustment. This has proved difficult, particularly in over‐identified cases. In this article, we show that the general AEL is Bartlett‐correctable and propose a two‐stage procedure for constructing accurate confidence regions. A naive AEL is first employed to address the empty set problem, and it is then Bartlett‐corrected through a resampling procedure. The finite‐sample performance of the proposed method is illustrated by simulations and an example. The Canadian Journal of Statistics 43: 42–59; 2015 © 2014 Statistical Society of Canada
Immunohistochemical localization of DPP10 in rat brain supports the existence of a Kv4/KChIP/DPPL ternary complex in neurons
Authors: Wang Wan‐Chen , Cheng Chau‐Fu , Tsaur Meei‐Ling 
Published: October 2014

ABSTRACTSubthreshold A‐type K+ currents (ISAs) have been recorded from the cell bodies of hippocampal and neocortical interneurons as well as neocortical pyramidal neurons. Kv4 channels are responsible for the somatodendritic ISAs. It has been proposed that neuronal Kv4 channels are ternary complexes including pore‐forming Kv4 subunits, K+ channel‐interacting proteins (KChIPs), and dipeptidyl peptidase‐like proteins (DPPLs). However, colocalization evidence was still lacking. The distribution of DPP10 mRNA in rodent brain has been reported but its protein localization remains unknown. In this study, we generated a DPP10 antibody to label DPP10 protein in adult rat brain by immunohistochemistry. Absent from glia, DPP10 proteins appear mainly in the cell bodies of DPP10(+) neurons, not only at the plasma membrane but also in the cytoplasm. At least 6.4% of inhibitory interneurons in the hippocampus coexpressed Kv4.3, KChIP1, and DPP10, with the highest density in the CA1 strata alveus/oriens/pyramidale and the dentate hilus. Colocalization of Kv4.3/KChIP1/DPP10 was also detected in at least 6.9% of inhibitory interneurons scattered throughout the neocortex. Both hippocampal and neocortical Kv4.3/KChIP1/DPP10(+) inhibitory interneurons expressed parvalbumin or somatostatin, but not calbindin or calretinin. Furthermore, we found colocalization of Kv4.2/Kv4.3/KChIP3/DPP10 in neocortical layer 5 pyramidal neurons and olfactory bulb mitral cells. Together, although DPP10 is also expressed in some brain neurons lacking Kv4 (such as parvalbumin‐ and somatostatin‐positive Golgi cells in the cerebellum), colocalization of DPP10 with Kv4 and KChIP at the plasma membrane of ISA‐expressing neuron somata supports the existence of Kv4/KChIP/DPPL ternary complex in vivo. J. Comp. Neurol. 523:608–628, 2015. © 2014 Wiley Periodicals, Inc.
Two Different Models to Predict Ionic‐Liquid Diffraction Patterns: Fixed‐Charge versus Polarizable Potentials
Authors: Campetella Marco , Gontrani Lorenzo , Leonelli Francesca , Bencivenni Luigi , Caminiti Ruggero 
Published: October 2014

AbstractThis study reports the performance of classical molecular dynamics (MD) in predicting the X‐ray diffraction patterns of butylammonium nitrate (BAN) and two derivatives, 4‐hydroxybutan‐1‐ammonium nitrate (4‐HOBAN) and 4‐methoxybutan‐1‐ammonium nitrate (4‐MeOBAN). The structure functions and radial distribution functions obtained from energy‐dispersive X‐ray diffraction spectra, recorded newly for BAN and for the first time for 4‐MeOBAN and 4‐HOBAN, are compared with the corresponding quantities calculated from MD trajectories, to access information on the morphology of these liquids. The different behavior of two force fields, a polarizable multipole force field and a fixed‐charge one supplemented by an explicit three‐body term, is shown. The three‐body force field proves to be superior in reproducing the intermediate q range, for which the polarizable force field gives the wrong peak position and intensities. In addition, both models can correctly account for the presence or absence of a low q peak in the scattering patterns.
Enhanced oxidative stability and water miscibility of conjugated linoleic acid complexed with lysine and arginine
Authors: Koohikamali Sara , Kamal Siti Mazlina Mustapa 
Published: October 2014

AbstractConjugated linoleic acids (CLA) are regarded as functional lipids. However, the water insolubility and oxidative instability of commercial CLA are barriers that limit the applications of CLA for fortification of aqueous‐based foods. In this study, production of a derivative of CLA with improved water solubility and extended shelf life through attachment of lysine (Lys) and arginine (Arg) into CLA structure was investigated. The evidence of the formation of Lys–CLA and Arg–CLA complexes was supported and verified by FT‐IR and 13C NMR analysis. The results indicated that the solubility of the Arg–CLA solution in pure water (pH 7) was greater than that of Lys–CLA at concentrations higher than 0.2% w/v. The peroxide values (PV) of the Lys–CLA and Arg–CLA increased by 1.4‐fold and 1.5‐fold, respectively; however, the PV of CLA increased by 15‐fold (after 12 h of heat treatment at 60°C). The PV mean of Lys–CLA was significantly (p < 0.05) lower than that of Arg–CLA, revealing that the oxidative stability of Lys–CLA is higher than that of Arg–CLA. This study showed that the incorporation of both Lys and Arg into the CLA can improve the water miscibility and oxidative stability of CLA, and expand the applications of CLA into food emulsions fortification.Practical applications: The water insolubility and oxidative instability of CLA are limiting barriers in application of CLA as a food fortifier. In order to improve the water solubility and oxidative stability of CLA, Lys and arginine, which are polar amino acids, have been incorporated into the CLA structure in forms of Lys–CLA and Arg–CLA complexes. This study showed that Lys can be an appropriate substitute for Arg in the Arg–CLA complex, which was already suggested in earlier works. In fact, the complexation of CLA with Lys improves the oxidative stability, water solubility, and the antioxidative capacity of CLA. Accordingly, the Lys–CLA complex provided and further described here may be used to fortify the liquid foods and drinks and thus, this product may expand the scope of CLA applications.The incorporation of both Lys and Arg into conjugated linoleic acid (CLA) can improve its water miscibility and oxidative stability and expand the applications of CLA in food emulsions fortification.
Bleaching with blends of bleaching earth and activated carbon reduces color and oxidation products of carp oil
Authors: Monte Mauricio L. , Monte Micheli L. , Pohndorf Ricardo S. , Crexi Valéria T. , Pinto Luiz A. A. 
Published: October 2014

Fish oil is characterized as a rich source of polyunsaturated fatty acids. Bleaching is one of the most important steps in oil refinement. This study evaluated the effect of the bleaching step of carp oil refinement on the total carotenoid content, the TBA value, and the color. The crude oil was obtained by acid silage of carp viscera, and it was refined by the following steps: degumming, neutralization, washing, drying and bleaching. Various percentages of adsorbent to the oil mass (1.4–5.6%, w/w) and of activated carbon to the total adsorbent mass (4–11%, w/w) were used to remove the color and oxidation products. The optimum condition was found with 2% of adsorbent (to the oil mass) and 10% of activated carbon in relation to the total adsorbent mass, showing the lowest losses of carotenoid content (44.4%), and highest decreases of dark oil color (87.5%) and of TBA value (79.7%). In the bleached carp oil, the sum of unsaturated fatty acids was approximately of 67% and the ω‐3/ω‐6 ratio of 1.22. A kinetic study of the bleaching step to the carotenoid content and TBA values was performed by the models of Brimberg and Langmuir‐Hinshelwood, which suitably fit the experimental data.Practical applications: A great number of studies are found in the literature on the pigment adsorption, oxidation products and free fatty acids in the bleaching step of vegetable oils by different adsorbents, however, there is little research that studies this step for fish oil. In this work, the best conditions for the bleaching of carp oil showed greater preservation of carotenoids, reductions in the value of TBA and in the darkening of the oil, resulting in a bleached oil with better quality and oxidative aspect. The neutralized and bleached oils extracted from carp viscera by the acid silage showed ω‐3/ω‐6 ratios from 1:1.21 to 1:1.22 and these values are in agreement with the literature for oil freshwater fish.Bleaching is one of the most important steps in the refinement process of oil leading to products of acceptable quality. The optimum conditions for bleaching carp oil were found with 2% of adsorbent to the oil mass and 10% of activated carbon in relation to total adsorbent mass. Under these conditions, the lowest losses of carotenoid content and highest decreases of the dark oil color and TBA value were shown.
Iron(III)‐Catalyzed C–H Functionalization: ortho‐Benzoyloxylation of N,N‐Dialkylanilines and Its Application to 1,4‐Benzoxazepines
Authors: Chiranjeevi Barreddi , Vinayak Botla , Parsharamulu Thupakula , PhaniBabu Vemulapalli S. , Jagadeesh Bharatam , Sridhar Balasubramanian , Chandrasekharam Malapaka 
Published: October 2014

AbstractA C–O bond‐formation reaction that proceeds through C–H functionalization of N,N‐dialkylanilines at the ortho‐position is presented. The iron‐catalyzed selective ortho‐benzoyloxylation follows a polar Friedel–Crafts‐like mechanism and is sensitive to the nucleophilicity of the anilines. The benzoyloxylation of a variety of N,N‐disubstituted anilines and N‐phenyl heterocycles is carried out under extremely mild conditions. Furthermore, the methodology has been successfully employed for the generation of 1,4‐benzoxazepines and o‐aminophenols.
Construction and Multiple Exterior Surface Functionalization of Giant Molecular Cages
Authors: Naseer Muhammad Moazzam , Wang De‐Xian , Zhao Liang , Wang Mei‐Xiang 
Published: October 2014

AbstractBy a one‐pot reaction strategy and a stepwise fragment‐coupling approach, three types of giant cage molecules with a triangular prism shape and an approximate cavity volume of 930 Å3 were synthesized. Through efficient aromatic nucleophilic substitution reactions of chlorotriazine with functionalized amines or aliphatic substitution reactions of the linking imino moieties with allyl bromide, the giant cages were successfully functionalized on the surface with multiple hydroxy, 2‐pyridyl, or allyl groups. As evidenced by variable‐temperature 1H NMR spectroscopy, the D3h‐ and C3v‐symmetric cage molecules underwent very slow conformational changes or deformation in solution because of their giant size and their flexible building units. Their giant cavities, different electronic interiors, and facile multiple exterior surface functionalization could render the molecular cages powerful three‐dimensional macrocyclic hosts that might find wide applications in supramolecular science.
Syntheses of Chiral Ferrocenophanes and Their Application to Asymmetric Catalysis
Authors: Zhang Qiying , Cui Xiuling , Chen Lianmei , Liu Haitao , Wu Yangjie 
Published: October 2014

AbstractN‐Substituted 2‐aza‐[3]‐ferrocenophanes were easily synthesized from 1,1′‐ferrocenedicarbaldehyde and aliphatic amines in high yields. One of the ferrocenophanes served as a ligand for the copper‐catalyzed oxidative coupling of 2‐naphthol derivatives to give the products in good yields with up to 92 % ee, and it also efficiently catalyzed the asymmetric Michael addition reaction as an organocatalyst.
Synthesis and NMR Analysis of 1,4‐Disubstituted 1,2,3‐Triazoles Tethered to Pyridine, Pyrimidine, and Pyrazine Rings
Authors: Bolje Aljoša , Urankar Damijana , Košmrlj Janez 
Published: October 2014

AbstractA combinatorial modular approach based on the “click” copper(I)‐catalysed azide–alkyne cycloaddition reaction was used to prepare a library of selected 1,4‐disubstituted 1,2,3‐triazoles differently functionalized with heteroaryl groups including pyridine, pyrimidine, and pyrazine. Three different copper(I) sources, i.e., CuSO4/sodium ascorbate, CuBr(PPh3)3, and (CuOTf)2·C6H6 were used to promote the coupling reactions of a range of aryl, heteroaryl, and heteroarylmethyl azides with alkyne “click” partners. As the target heteroaryl triazoles were designed to serve as advanced ligands or ligand precursors for metal coordination, they were fully characterized by 1H, 13C, and 15N NMR spectroscopy. The resonances were assigned on the basis of 1D and 2D NMR experiments. 1H–15N gs‐HMBC was used as a practical tool to determine 15N NMR chemical shifts at the natural abundance level of the 15N isotope.
Evaluation of bone length and number of osteotomies utilizing the osteocutaneous radial forearm free flap for mandible reconstruction: An 8‐year review of complications and flap survival
Authors: Silverman Dustin A. , Przylecki Wojciech H. , Arganbright Jill M. , Shnayder Yelizaveta , Kakarala Kiran , Nazir Niaman , Tsue Terance T. , Girod Douglas A. , Andrews Brian T. 
Published: October 2014

AbstractBackgroundThe purpose of this study was to assess the impact of bone harvest length and multiple osteotomies on osteocutaneous radial forearm free flap (RFFF) complication rates.MethodsA retrospective chart review was conducted for patients undergoing osteocutaneous RFFF reconstruction during an 8‐year period.ResultsOne hundred fifty‐five osteocutaneous RFFF procedures were performed. Recipient‐site flap complications were 18 of 55 (32.7%) when bone harvest length was less than 7 cm and 40 of 100 (40.0%) when it was ≥7 cm. No osteotomies were performed in 69 of 155 cases with a corresponding complication rate of 30.4% (21 of 69). One osteotomy was utilized in 69 of 155 flaps, whereas 17 of 155 required more than 1 osteotomy; complications were experienced in 42% (29 of 69) and 47% (8 of 17) of these cases, respectively.ConclusionOsteocutaneous RFFF complication rates were only slightly higher when the bone length was ≥7 cm or when multiple osteotomies were required. © 2015 Wiley Periodicals, Inc. Head Neck 38: 434–438, 2016
Ready or Not
Authors: Springer Sheree E. , Wilson Tonia J. , Dole Janice A. 
Published: October 2014

AbstractResearch shows that many students entering postsecondary education are unprepared for college reading demands. This article highlights college reading readiness according to four essential reading skills. We illustrate these skills by featuring vignettes of high school seniors who are college‐ready and not college‐ready. Then we contextualize the skills based on current research. Finally, we provide specific instructional strategies and approaches to these essential skills so high school teachers can help their students successfully transition to college literacy demands.
Optimization of blend parameters for the fabrication of polycaprolactone‐silicon based ormoglass nanofibers by electrospinning
Authors: Sachot Nadège , Castano Oscar , Planell Josep A. , Engel Elisabeth 
Published: October 2014

AbstractElectrospinning is a method that can be used to efficiently produce scaffolds that mimic the fibrous structure of natural tissue, such as muscle structures or the extracellular matrix of bone. The technique is often used as a way of depositing composites (organic/inorganic materials) to obtain bioactive nanofibers which have the requisite mechanical properties for use in tissue engineering. However, many factors can influence the formation and collection of fibers, including experimental variables such as the parameters of the solution of the electrospun slurry. In this study, we assessed the influence of the polymer concentration, glass content and glass hydrolysis level on the morphology and thickness of fibers produced by electrospinning for a PCL‐(Si‐Ca‐P2) bioactive ormoglass—organically modified glass—blend. Based on previous assays, this combination of materials shows good angiogenic and osteogenic properties, which gives it great potential for use in tissue engineering. The results of our study showed that blend preparation directly affected the features of the resulting fibers, and when the parameters of the blend are precisely controlled, fibers with a regular diameter could be produced fairly easily when 2,2,2‐trifluoroethanol was used as a solvent instead of tetrahydrofuran. The diameter of the homogeneous fibers ranged from 360 to 620 nm depending on the experimental conditions used. This demonstrates that experimental optimization of the electrospinning process is crucial in order to obtain a deposit of hybrid nanofibers with a regular shape. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 1287–1293, 2015.