bluuebunny/crossref_metadata_2025_split huggingface dataset:
Defining the Interaction of Human Soluble Lectin ZG16p and Mycobacterial Phosphatidylinositol Mannosides
Authors: Hanashima Shinya , Götze Sebastian , Liu Yan , Ikeda Akemi , Kojima‐Aikawa Kyoko , Taniguchi Naoyuki , Varón Silva Daniel , Feizi Ten , Seeberger Peter H. , Yamaguchi Yoshiki 
Published: April 2015

AbstractZG16p is a soluble mammalian lectin that interacts with mannose and heparan sulfate. Here we describe detailed analysis of the interaction of human ZG16p with mycobacterial phosphatidylinositol mannosides (PIMs) by glycan microarray and NMR. Pathogen‐related glycan microarray analysis identified phosphatidylinositol mono‐ and di‐mannosides (PIM1 and PIM2) as novel ligand candidates of ZG16p. Saturation transfer difference (STD) NMR and transferred NOE experiments with chemically synthesized PIM glycans indicate that PIMs preferentially interact with ZG16p by using the mannose residues. The binding site of PIM was identified by chemical‐shift perturbation experiments with uniformly 15N‐labeled ZG16p. NMR results with docking simulations suggest a binding mode of ZG16p and PIM glycan; this will help to elucidate the physiological role of ZG16p.
Asymmetric NaBH4 1,4‐Reduction of C3‐Disubstituted 2‐Propenoates Catalyzed by a Diamidine Cobalt Complex
Authors: Shuto Yoshihiro , Yamamura Tomoya , Tanaka Shinji , Yoshimura Masahiro , Kitamura Masato 
Published: April 2015

AbstractA new Co complex of a unique diamidine ligand catalyzes asymmetric NaBH4 reduction of C3‐disubstituted (E)‐ and (Z)‐2‐propenoates, including C3‐oxygen‐ and nitrogen‐substituted substrates with high enantioselectivity. Analysis by X‐ray diffraction, 1H NMR spectroscopy, ring‐opening radical‐clock and D‐labeling reactions, and the structure/selectivity relationship suggest that a mechanism of CoH‐involved non‐single‐electron transfer 1,4‐addition differentiates the C2 enantioface. Involvement of CoH species has been supported by quantitative isolation of a new type of CoH2(BH3)2 complex.
Catalytic Surface Promotion of Composite Cathodes in Protonic Ceramic Fuel Cells
Authors: Solís Cecilia , Navarrete Laura , Bozza Francesco , Bonanos Nikolaos , Serra José M. 
Published: April 2015

AbstractComposite cathodes based on an electronic conductor and a protonic conductor show advantages for protonic ceramic fuel cells. In this work, the performance of a La5.5WO11.25−δ/La0.8Sr0.2MnO3+δ (LWO/LSM) composite cathode in a fuel cell based on an LWO protonic conducting electrolyte is shown and catalytically improved. The limiting processes were first unambiguously associated to surface steps, and the reaction rate was significantly enhanced by 1) tailoring the catalytic activity through electrode surface impregnation with intrinsically catalytic nanoparticles and 2) electrochemical activation of surface species by imposing a net current through the electrode.
Effect of Adding CeO2 to RuO2–IrO2 Mixed Nanocatalysts: Activity towards the Oxygen Evolution Reaction and Stability in Acidic Media
Authors: Audichon Thomas , Morisset Sophie , Napporn Teko W. , Kokoh K. Boniface , Comminges Clément , Morais Cláudia 
Published: April 2015

AbstractTrimetallic Ru‐, Ir‐, and Ce‐oxide materials were synthesized by using a hydrolysis method in ethanol medium and characterized to obtain information on their crystallographic structure, morphology, and chemical composition. Voltammetric measurements allowed us to evaluate the properties of these catalysts through the determination of their capacitance, active site number, and accessibility. The effect of cerium on the oxygen evolution reaction (OER) was also evaluated electrochemically and the catalytic layer stability was measured by using a repetitive cyclic voltammetry procedure. The catalysts stability in an acidic medium is not significantly affected by cerium addition. Moreover, the oxygen mobility in the ceria crystallographic structure may contribute to an enhanced electrocatalytic activity per active site. Tafel slope values were determined from electrochemical impedance spectroscopy fitting parameters and indicate the same OER rate‐determining step for mono‐, bi‐, and trimetallic catalysts.
Synthesis, Crystal Structure and Magnetic Properties of a Novel Heterobimetallic Rhenium(IV)–Dysprosium(III) Chain
Authors: Pejo Carolina , Guedes Guilherme P. , Novak Miguel A. , Speziali Nivaldo L. , Chiozzone Raúl , Julve Miguel , Lloret Francesc , Vaz Maria G. F. , González Ricardo 
Published: April 2015

AbstractThe use of the mononuclear rhenium(IV) precursor [ReBr5(H2pydc)]− (H2pydc=3,5‐pyridinedicarboxylic acid) as a metalloligand towards dysprosium(III) afforded the first heterobimetallic ReIV–DyIII complex. Crystal structures and static and dynamic magnetic properties of both rhenium‐containing species are reported herein. The 5d–4f compound shows an extended 1D structure and the AC magnetic measurements reveal frequency dependence at low temperature suggesting slow relaxation of the magnetization.
Organocatalytic Highly Enantioselective Substitution of 3‐(1‐Tosylalkyl)indoles with Oxindoles Enables the First Total Synthesis of (+)‐Trigolutes B
Authors: Huang Jian‐Zhou , Zhang Chen‐Long , Zhu Yi‐Fan , Li Lu‐Lu , Chen Dian‐Feng , Han Zhi‐Yong , Gong Liu‐Zhu 
Published: April 2015

AbstractA highly enantioselective organocatalytic substitution of 3‐(1‐tosylalkyl)indoles with oxindoles has been established by using chiral bifunctional organocatalysts, providing an efficient entry to multiply functionalized 3,3′‐disubstituted oxindoles, and was exploited as the key step to enable the first asymmetric total synthesis of optically pure (+)‐trigolutes B to be accomplished in a concise manner, within seven steps with an 18 % overall yield.
Crown‐Shaped Tungstogermanates as Solvent‐Controlled Dual Systems in the Formation of Vesicle‐Like Assemblies
Authors: Artetxe Beñat , Reinoso Santiago , San Felices Leire , Gutiérrez‐Zorrilla Juan M. , García José A. , Haso Fadi , Liu Tianbo , Vicent Cristian 
Published: April 2015

AbstractReaction of early lanthanides, GeO2, and Na2WO4 in a NaOAc buffer results in large crown‐shaped polyoxometalates based on [Ln2GeW10O38]6− subunits. By using Ni2+ as a crystallizing agent, [Na⊂Ln12Ge6W60O228(H2O)24]35− (Na⊂Ln12) hexamers formed by alternating β(1,5)/β(1,8) subunits were obtained for Ln=Pr, Nd. The addition of K+ led to a similar anion for Ln=Sm, namely, [K⊂Sm12Ge6W60O228(H2O)22]35− (K⊂Sm12) and [K⊂K7Ln24Ge12W120O444(OH)12(H2O)64]52− (K⊂Ln24) dodecamers that consist of a central core identical to K⊂Sm12 decorated with six external γ(3,4) subunits for Ln=Pr, Nd. These anions dissociate in water into hexameric cores and monomeric entities, as shown by ESI mass spectrometry. The former self‐assemble into spherical, hollow, and single‐layered blackberry‐type structures with radii of approximately 75 nm, as monitored by laser light scattering (LLS) and TEM techniques. Analogous studies performed for K⊂Nd24 in water/acetone mixtures show that the dodecamers remain stable and form in turn their own type of blackberries with sizes that increase from approximately 20 to 50 nm with increasing acetone content. This control over both the composition and size of the vesicle‐like assemblies is achieved for the first time by modifying the architecture of the species that undergoes supramolecular association through the solvent polarity.
Micelle‐Triggered β‐Hairpin to α‐Helix Transition in a 14‐Residue Peptide from a Choline‐Binding Repeat of the Pneumococcal Autolysin LytA
Authors: Zamora‐Carreras Héctor , Maestro Beatriz , Strandberg Erik , Ulrich Anne S. , Sanz Jesús M. , Jiménez M. Ángeles 
Published: April 2015

AbstractCholine‐binding modules (CBMs) have a ββ‐solenoid structure composed of choline‐binding repeats (CBR), which consist of a β‐hairpin followed by a short linker. To find minimal peptides that are able to maintain the CBR native structure and to evaluate their remaining choline‐binding ability, we have analysed the third β‐hairpin of the CBM from the pneumococcal LytA autolysin. Circular dichroism and NMR data reveal that this peptide forms a highly stable native‐like β‐hairpin both in aqueous solution and in the presence of trifluoroethanol, but, strikingly, the peptide structure is a stable amphipathic α‐helix in both zwitterionic (dodecylphosphocholine) and anionic (sodium dodecylsulfate) detergent micelles, as well as in small unilamellar vesicles. This β‐hairpin to α‐helix conversion is reversible. Given that the β‐hairpin and α‐helix differ greatly in the distribution of hydrophobic and hydrophilic side chains, we propose that the amphipathicity is a requirement for a peptide structure to interact and to be stable in micelles or lipid vesicles. To our knowledge, this “chameleonic” behaviour is the only described case of a micelle‐induced structural transition between two ordered peptide structures.
Directed Hydrogenations and an Ireland–Claisen Rearrangement Linked to Evans–Tishchenko Chemistry: The Highly Efficient Total Synthesis of the Marine Cyclodepsipeptide Doliculide
Authors: Chen Tao , Altmann Karl‐Heinz 
Published: April 2015

AbstractTwo new convergent total syntheses have been developed for the cytotoxic, actin microfilament‐stabilizing marine cyclodepsipeptide doliculide (1). A key strategic element of both routes is the establishment of the central stereogenic center of the characteristic polydeoxypropionate stereotriad by means of a hydroxyl‐directed catalytic hydrogenation of a trisubstituted double bond. The requisite olefin substrates were obtained through a modified Suzuki–Miyaura coupling or through Ireland–Claisen rearrangement of a propionate ester, respectively; the latter was the direct result of a highly selective Evans–Tishchenko reduction of a hydroxy ketone that had been obtained in a stereoselective Paterson aldol reaction. Doliculide (1) was finally obtained in a total number of 17 or 15 (14) linear steps, respectively, which represents a substantial improvement over previous syntheses of this highly bioactive natural product.
Enantiomeric Cyclic Peptides with Different Caco‐2 Permeability Suggest Carrier‐Mediated Transport
Authors: Marelli Udaya Kiran , Bezençon Jacqueline , Puig Eduard , Ernst Beat , Kessler Horst 
Published: April 2015

AbstractRecently, oral absorption of cyclic hexapeptides was improved by N‐methylation of their backbone amides. However, the number and position of N‐methylations or of solvent exposed NHs did not correlate to intestinal permeability, measured in a Caco‐2 model. In this study, we investigate enantiomeric pairs of three polar and two lipophilic peptides to demonstrate the participation of carrier‐mediated transporters. As expected, all the enantiomeric peptides exhibited identical lipophilicity (logD7.4) and passive transcellular permeability determined by the parallel artificial membrane permeability assay (PAMPA). However, the enantiomeric polar peptides exhibited different Caco‐2 permeability (Papp) in both directions a–b and b–a. The same trend was observed for one of the lipophilic peptide, whereas the second lipophilic enantiomer pair showed identical Caco‐2 permeability (within the errors). These findings provide the first evidence for the involvement of carrier‐mediated transport for peptides, especially for those of polar nature.
Solid Polymer Substrates and Coated Fibers Containing 2,4,6‐Trinitrobenzene Motifs as Smart Labels for the Visual Detection of Biogenic Amine Vapors
Authors: Pablos Jesús L. , Vallejos Saúl , Muñoz Asunción , Rojo María J. , Serna Felipe , García Félix C. , García José M. 
Published: April 2015

AbstractAttempts to polymerize trinitrobenzene derivatives (TNB) have been fruitless so far. Accordingly, polymers containing TNB have not been exploited in spite of their envisaged potential applications. Here, we describe two ways for preparing polymers with TNB moieties thus overcoming the previously reported polymerization impairments. We also report on the exploitation of the materials, both obtained as tractable transparent films and coated fibers, as smart labels for the visual detection of amine vapors. More precisely, amines in the atmosphere surrounding the sensory materials diffuse into them reacting with the TNB motifs forming highly colored Meisenheimer complexes, giving rise to development of color and to the naked eye sensing phenomenon. This is the case of highly volatile amines, such as trimethylamine, produced in food spoilage, specifically in the deterioration of fish or meat, for which the color development of the smart labels can be used as a visual test for food freshness.
Chirality and Gravitational Parity Violation
Authors: Bargueño Pedro 
Published: April 2015

AbstractIn this review, parity‐violating gravitational potentials are presented as possible sources of both true and false chirality. In particular, whereas phenomenological long‐range spin‐dependent gravitational potentials contain both truly and falsely chiral terms, it is shown that there are models that extend general relativity including also coupling of fermionic degrees of freedom to gravity in the presence of torsion, which give place to short‐range truly chiral interactions similar to that usually considered in molecular physics. Physical mechanisms which give place to gravitational parity violation together with the expected size of the effects and their experimental constraints are discussed. Finally, the possible role of parity‐violating gravity in the origin of homochirality and a road map for future research works in quantum chemistry is presented. Chirality 27:375–381, 2015.© 2015 Wiley Periodicals, Inc.
Participants' barriers to diagnostic resolution and factors associated with needing patient navigation
Authors: Krok‐Schoen Jessica L. , Brewer Brittany M. , Young Gregory S. , Weier Rory C. , Tatum Cathy M. , DeGraffinreid Cecilia R. , Paskett Electra D. 
Published: April 2015

BACKGROUNDPatient navigation (PN) may improve cancer care by identifying and removing patient‐reported barriers to care. In 2012, the American College of Surgeons Commission on Cancer (CoC) announced that health care facilities seeking CoC accreditation must have PN processes in place by January 1, 2015. Given these unfunded mandates, hospitals are looking for cost‐effective ways to implement PN. This study examined demographic and psychosocial predictors of barriers to diagnostic resolution among individuals with a cancer screening abnormality enrolled in the Ohio Patient Navigation Research Project.METHODSData were obtained from patients who received care at 1 of 9 Ohio Patient Navigation Research Project intervention clinics. Descriptive statistics and logistic regression models were used.RESULTSThere were 424 participants, and 151 (35.6%) reported a barrier to diagnostic resolution within 90 days of study consent. The most commonly reported barriers were misconceptions about a test or treatment (16.4%), difficulty in communicating with the provider (15.0%), and scheduling problems (11.5%). Univariate analyses indicated that race, education, employment, income, insurance, clinic type, friend support, and physical and psychological functioning were significantly associated with reporting a barrier to diagnostic resolution. Multivariate analyses found that comorbidities (odds ratio, 1.65; 95% confidence interval, 1.04‐2.61) and higher intrusive thoughts and feelings (odds ratio, 1.25; 95% confidence interval, 1.10‐1.41) were significantly associated with reporting a barrier to diagnostic resolution.CONCLUSIONSThe results suggest that demographic and psychosocial factors are associated with barriers to diagnostic resolution. To ensure compliance with the CoC mandate and provide timely care to all patients, CoC‐accredited facilities can systematically identify the patients most likely to have barriers to care and assign them to PN. Cancer 2015;121:2757‐2764. © 2015 American Cancer Society
Morphology, innervation, and peripheral sensory cells of the siphon of aplysia californica
Authors: Carrigan Ian D. , Croll Roger P. , Wyeth Russell C. 
Published: April 2015

ABSTRACTThe siphon of Aplysia californica has several functions, including involvement in respiration, excretion, and defensive inking. It also provides sensory input for defensive withdrawals that have been studied extensively to examine mechanisms that underlie learning. To better understand the neuronal bases of these functions, we used immunohistochemistry to catalogue peripheral cell types and innervation of the siphon in stage 12 juveniles (chosen to allow observation of tissues in whole‐mounts). We found that the siphon nerve splits into three major branches, leading ultimately to a two‐part FMRFamide‐immunoreactive plexus and an apparently separate tyrosine hydroxylase–immunoreactive plexus. Putative sensory neurons included four distinct types of tubulin‐immunoreactive bipolar cells (one likely also tyrosine hydroxylase immunoreactive) that bore ciliated dendrites penetrating the epithelium. A fifth bipolar neuron type (tubulin‐ and FMRFamide‐immunoreactive) occurred deeper in the tissue, associated with part of the FMRFamide‐immunoreactive plexus. Our observations emphasize the structural complexity of the peripheral nervous system of the siphon, and the importance of direct tests of the various components to better understand the functioning of the entire organ, including its role in defensive withdrawal responses. J. Comp. Neurol. 523:2409–2425, 2015. © 2015 Wiley Periodicals, Inc.
A BDDC Algorithm with Deluxe Scaling for Three‐Dimensional H(curl) Problems
Authors: Dohrmann Clark R. , Widlund Olof B. 
Published: April 2015

AbstractIn this paper, we present and analyze a BDDC algorithm for a class of elliptic problems in the three‐dimensional H(curl) space. Compared with existing results, our condition number estimate requires fewer assumptions and also involves two fewer powers of log(H/h), making it consistent with optimal estimates for other elliptic problems. Here, H/h is the maximum of Hi/hi over all subdomains, where Hi and hi are the diameter and the smallest element diameter for the subdomain Ωi. The analysis makes use of two recent developments. The first is a new approach to averaging across the subdomain interfaces, while the second is a new technical tool that allows arguments involving trace classes to be avoided. Numerical examples are presented to confirm the theory and demonstrate the importance of the new averaging approach in certain cases. © 2016 Wiley Periodicals, Inc.
Acetyl Methyl Torsion in N‐Ethylacetamide: A Challenge for Microwave Spectroscopy and Quantum Chemistry
Authors: Kannengießer Raphaela , Lach Marcel J. , Stahl Wolfgang , Nguyen Ha Vinh Lam 
Published: April 2015

AbstractThe gas‐phase structures and parameters describing acetyl methyl torsion of N‐ethylacetamide are determined with high accuracy, using a combination of molecular beam Fourier‐transform microwave spectroscopy and quantum chemical calculations. Conformational studies at the MP2 level of theory yield four minima on the energy surface. The most energetically favorable conformer, which possesses C1 symmetry, is assigned. Due to the torsional barrier of 73.4782(1) cm−1 of the acetyl methyl group, fine splitting up to 4.9 GHz is found in the spectrum. The conformational structure is not only confirmed by the rotational constants, but also by the orientation of the internal rotor. The 14N quadrupole hyperfine splittings are analyzed and the deduced coupling constants are compared with the calculated values.
Preparation of Cyclodextrin–Iron Species in Water by Laser Ablation: Secondary Ion Mass Spectrometry
Authors: Halaszova Sona , Jerigova Monika , Lorenc Dusan , Velic Dusan 
Published: April 2015

AbstractSupramolecular complexes between cyclodextrin and iron species are studied by using secondary ion mass spectrometry. The iron species are prepared by pulsed‐laser ablation of bulk iron in water; this gives Fe+ (56 m/z) and FexOy+ (x, y=1–7) species. Cyclodextrin is added to the water either before or after the laser ablation. When it is added before laser ablation, molecular fragments of cyclodextrin are detected as dehydrated glucopyranose units (C6H8O4+) associated with Fe+, FeO+, and Fe2O+ species. The focus is to observe supramolecular host–guest complexes or adducts between intact molecules of cyclodextrin and iron species. When cyclodextrin is added after laser ablation, the relevant peak at 1210 m/z is observed and assigned as C42H67O35FeNa+, which corresponds to a cyclodextrin molecule minus three H atoms. Two possible explanations of this finding are the presence of the host–guest C42H67O35Na–Fe complex, in which Fe is in the cavity, or the presence of the adduct C42H67O34Na–FeO with FeO on the outer surface; the formation of these complexes are supported by the hydrophobicity of Fe and hydrophilicity of FeO, respectively. Due to the presence of 12 % of intact C42H70O35Na–Fe complex and an estimated Fe/FeO ratio of approximately 102, host–guest formation is assumed to be more significant.
Tuning of ZIF‐Derived Carbon with High Activity, Nitrogen Functionality, and Yield – A Case for Superior CO2 Capture
Authors: Gadipelli Srinivas , Guo Zheng Xiao 
Published: April 2015

AbstractA highly effective and facile synthesis route is developed to create and tailor metal‐decorated and nitrogen‐functionalized active microporous carbon materials from ZIF‐8. Clear metal‐ and pyrrolic‐N‐induced enhancements of the cyclic CO2 uptake capacities and binding energies are achieved, particularly at a much lower carbonization temperature of 700 °C than those often reported (1000 °C). The high‐temperature carbonization can enhance the porosity but only at the expense of considerable losses of sample yield and metal and N functional sites. The findings are comparatively discussed with carbons derived from metal–organic frameworks (MOFs) reported previously. Furthermore, the porosity of the MOF‐derived carbon is critically dependent on the structure of the precursor MOF and the crystal growth. The current strategy offers a new and effective route for the creation and tuning of highly active and functionalized carbon structures in high yields and with low energy consumption.
A Rational Approach to CO2 Capture by Imidazolium Ionic Liquids: Tuning CO2 Solubility by Cation Alkyl Branching
Authors: Corvo Marta C. , Sardinha João , Casimiro Teresa , Marin Graciane , Seferin Marcus , Einloft Sandra , Menezes Sonia C. , Dupont Jairton , Cabrita Eurico J. 
Published: April 2015

AbstractBranching at the alkyl side chain of the imidazolium cation in ionic liquids (ILs) was evaluated towards its effect on carbon dioxide (CO2) solubilization at 10 and 80 bar (1 bar=1×105 Pa). By combining high‐pressure NMR spectroscopy measurements with molecular dynamics simulations, a full description of the molecular interactions that take place in the IL–CO2 mixtures can be obtained. The introduction of a methyl group has a significant effect on CO2 solubility in comparison with linear or fluorinated analogues. The differences in CO2 solubility arise from differences in liquid organization caused by structural changes in the cation. ILs with branched cations have similar short‐range cation–anion orientations as those in ILs with linear side chains, but present differences in the long‐range order. The introduction of CO2 does not cause perturbations in the former and benefits from the differences in the latter. Branching at the cation results in sponge‐like ILs with enhanced capabilities for CO2 capture.