bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Stability of Pd/Al2O3 Prepared from Palladium Nanoparticles Protected with Carbosilane Dendrons in the Dimethyl Ether Steam Reforming Reaction
Authors: Ramos Erika , Davin Laia , Angurell Inma , Ledesma Cristian , Llorca Jordi 
Published: May 2015

AbstractThe dimethyl ether steam reforming reaction to generate hydrogen was tested over 1 wt % Pd/Al2O3 catalysts prepared from different precursors. The conventional catalyst prepared by incipient wetness impregnation from palladium nitrate underwent strong deactivation under reforming conditions at 823 K because of metal sintering and carbon deposition. The same occurred over the catalyst prepared from preformed Pd nanoparticles protected with dodecanethiol. In contrast, catalysts prepared from Pd nanoparticles protected with carbosilane dendrons showed enhanced stability and good performance for the production of hydrogen. This was because of the formation of SiO2 at the Pd–Al2O3 interface that acted as a pinning center and prevented Pd migration under the reaction conditions as well as the accumulation of carbon.
Conversion of Pyrolysis Fuel Oils by a Dielectric Barrier Discharge Reactor in the Presence of Methane and Ethane
Authors: Khani Mohammad R. , Khosravi Attieh , Gharibi Mahtab , Shahabi Seyedeh S. , Guy Elham Dejban , Shokri Babak 
Published: May 2015

AbstractPyrolysis fuel oil cracking by low‐temperature plasma was investigated in a dielectric barrier discharge reactor at ambient pressure. The promoting effect of methane and ethane in the formation of products was evaluated by altering the working gas from methane to ethane. In addition, the production of hydrocarbons and hydrogen was analyzed. The main parameters were working gas type, flow rate, and applied voltage. Increasing the applied voltage enhanced the production rate of valuable petrochemical compounds like gas and liquid. Alteration of the working gas flow rate led to a higher production rate of H2, C2, C3, and C4. Chemical investigations were performed by optical emission spectroscopy of plasma and the main mechanisms are described.
Origin of the Increased Li+‐Storage Capacity of Stacked SnS2/Graphene Nanocomposite
Authors: Qu Baihua , Ji Ge , Ding Bo , Lu Meihua , Chen Weixiang , Lee Jim Yang 
Published: May 2015

AbstractThere has been strong recent interest in using SnS2/graphene nanocomposites for reversible Li+ storage. Although SnS2 and graphene are 2D nanomaterials, many of their composites reported to date have a random 3D structure. We present here a stacked SnS2/graphene nanocomposite that retains many of the original 2D features of the graphene nanosheets. As a result, significantly improved Li+‐storage properties were shown including: 1) good cycle stability (delithiation capacity of 1063 mAh g−1 for 100 cycles at 200 mA g−1 and 918 mAh g−1 for 500 cycles at 1 A g−1); 2) high first‐cycle coulombic efficiency (89.7 %); 3) high reversibility of the conversion reaction SnS2+4 Li++4 e−→Sn+2 Li2S (87.5 %); and 4) high rate performance (712 mAh g−1 at 5 A g−1). Such good performance corresponds well with a 2D construction, in which Sn nanoparticles are firmly held by graphene nanosheets. The conversion reaction becomes more reversible in the presence of the Sn nanoparticles to contribute to the additional storage capacity.
Solid‐Phase Parallel Synthesis of Functionalised Medium‐to‐Large Cyclic Peptidomimetics through Three‐Component Coupling Driven by Aziridine Aldehyde Dimers
Authors: Treder Adam P. , Hickey Jennifer L. , Tremblay Marie‐Claude J. , Zaretsky Serge , Scully Conor C. G. , Mancuso John , Doucet Annie , Yudin Andrei K. , Marsault Eric 
Published: May 2015

AbstractThe first solid‐phase parallel synthesis of macrocyclic peptides using three‐component coupling driven by aziridine aldehyde dimers is described. The method supports the synthesis of 9‐ to 18‐membered aziridine‐containing macrocycles, which are then functionalized by nucleophilic opening of the aziridine ring. This constitutes a robust approach for the rapid parallel synthesis of macrocyclic peptides.
Ni‐Catalyzed Asymmetric Cycloisomerization of Dienes by Using TADDOL Phosphoramidites
Authors: Schmitz Christian , Leitner Walter , Franciò Giancarlo 
Published: May 2015

AbstractA library of α,α,α,α‐tetraaryl‐1,3‐dioxolane‐4,5‐dimethanol (TADDOL)‐based phosphoramidites has been synthesized and applied in the Ni‐catalyzed cycloisomerization of different dienes. Through the systematic variation of the three structural motifs of the lead structure, that is, the amine moiety, the protecting group, and the aryl substituents, the ligand features could be optimized for the asymmetric cycloisomerization of the model substrate diethyl diallylmalonate. The substrate scope of the new catalytic system was extended to other diallylic substrates, including unsymmetrical dienes. Overall remarkably high activities of up to approximately 13 500 h−1, very high selectivities toward five‐membered exo‐methylenecyclopentanes, and enantioselectivities of up to 92 % ee have been achieved.
Distinct Spacing Between Anionic Groups: An Essential Chemical Determinant for Achieving Thiophene‐Based Ligands to Distinguish β‐Amyloid or Tau Polymorphic Aggregates
Authors: Klingstedt Therése , Shirani Hamid , Mahler Jasmin , Wegenast‐Braun Bettina M. , Nyström Sofie , Goedert Michel , Jucker Mathias , Nilsson K. Peter R. 
Published: May 2015

AbstractThe accumulation of protein aggregates is associated with many devastating neurodegenerative diseases and the existence of distinct aggregated morphotypes has been suggested to explain the heterogeneous phenotype reported for these diseases. Thus, the development of molecular probes able to distinguish such morphotypes is essential. We report an anionic tetrameric oligothiophene compound that can be utilized for spectral assignment of different morphotypes of β‐amyloid or tau aggregates present in transgenic mice at distinct ages. The ability of the ligand to spectrally distinguish between the aggregated morphotypes was reduced when the spacing between the anionic substituents along the conjugated thiophene backbone was altered, which verified that specific molecular interactions between the ligand and the protein aggregate are necessary to detect aggregate polymorphism. Our findings provide the structural and functional basis for the development of new fluorescent ligands that can distinguish between different morphotypes of protein aggregates.
Synthesis and Mechanistic Study of Cyclic Oxoguanidines via Zn(OTf)2‐Catalyzed Guanylation/Amidation from Readily Available Amino Acid Esters and Carbodiimides
Authors: Chi Yue , Xu Ling , Du Shanshan , Yan Haihan , Zhang Wen‐Xiong , Xi Zhenfeng 
Published: May 2015

AbstractThe Zn(OTf)2‐catalyzed guanylation/amidation from readily available amino acid esters and carbodiimides is achieved to provide efficiently various cyclic oxoguanidines, including 2‐amino‐1H‐imidazol‐5(4H)‐ones and 2‐aminoquinazolin‐4(3H)‐ones in medium‐to‐high yields. It is the first time that an ammonium salt has been used in a guanylation reaction. The application of cyclic oxoguanidines to provide the conjugated heterocyclic compounds via oxidative CN formation or aldol reaction is explored. The reaction mechanism is well elucidated by the isolation and characterization of three important intermediates.
Asymmetric Total Synthesis of ent‐Pyripyropene A
Authors: Fuse Shinichiro , Ikebe Ayako , Oosumi Kazuya , Karasawa Tomoya , Matsumura Keisuke , Izumikawa Miho , Johmoto Kohei , Uekusa Hidehiro , Shin‐ya Kazuo , Doi Takayuki , Takahashi Takashi 
Published: May 2015

AbstractAn asymmetric total synthesis of ent‐pyripyropene A was achieved by a convergent synthetic route. We used our originally developed TiIII‐catalyzed radical cyclization to construct an AB‐ring portion that consisted of a trans‐decalin skeleton with five contiguous stereogenic centers. The coupling between the AB‐ring and the DE‐ring portions, and a subsequent C‐ring cyclization, led to the total synthesis of ent‐pyripyropene A. An evaluation of the insecticidal activity of ent‐pyripyropene A against two aphid species revealed that ent‐pyripyropene A was 35–175 times less active than naturally occurring pyripyropene A. This result indicated that the biological target of pyripyropene A recognizes the absolute configuration of pyripyropene A.
Luminescence‐Functionalized Metal–Organic Frameworks Based on a Ruthenium(II) Complex: A Signal Amplification Strategy for Electrogenerated Chemiluminescence Immunosensors
Authors: Xiong Cheng‐Yi , Wang Hai‐Jun , Liang Wen‐Bin , Yuan Ya‐Li , Yuan Ruo , Chai Ya‐Qin 
Published: May 2015

AbstractNovel luminescence‐functionalized metal–organic frameworks (MOFs) with superior electrogenerated chemiluminescence (ECL) properties were synthesized based on zinc ions as the central ions and tris(4,4′‐dicarboxylicacid‐2,2′‐bipyridyl)ruthenium(II) dichloride ([Ru(dcbpy)3]2+) as the ligands. For potential applications, the synthesized MOFs were used to fabricate a “signal‐on” ECL immunosensor for the detection of N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP). As expected, enhanced ECL signals were obtained through a simple fabrication strategy because luminescence‐functionalized MOFs not only effectively increased the loading of [Ru(dcbpy)3]2+, but also served as a loading platform in the ECL immunosensor. Furthermore, the proposed ECL immunosensor had a wide linear range from 5 pg mL−1 to 25 ng mL−1 and a relatively low detection limit of 1.67 pg mL−1 (signal/noise=3). The results indicated that luminescence‐functionalized MOFs provided a novel amplification strategy in the construction of ECL immunosensors and might have great prospects for application in bioanalysis.
3,6,7‐Triamino‐[1,2,4]triazolo[4,3‐b][1,2,4]triazole: A Non‐toxic, High‐Performance Energetic Building Block with Excellent Stability
Authors: Klapötke Thomas M. , Schmid Philipp C. , Schnell Simon , Stierstorfer Jörg 
Published: May 2015

AbstractA novel strategy for the design of energetic materials that uses fused amino‐substituted triazoles as energetic building blocks is presented. The 3,6,7‐triamino‐7H‐[1,2,4]triazolo[4,3‐b][1,2,4]triazolium (TATOT) motif can be incorporated into many ionic, nitrogen‐rich materials to form salts with advantages such as remarkably high stability towards physical or mechanical stimuli, excellent calculated detonation velocity, and toxicity low enough to qualify them as “green explosives”. Neutral TATOT can be synthesized in a convenient and inexpensive two‐step protocol in high yield. To demonstrate the superior properties of TATOT, 13 ionic derivatives were synthesized and their chemical‐ and physicochemical properties (e.g., sensitivities towards impact, friction and electrostatic discharge) were investigated extensively. Low toxicity was demonstrated for neutral TATOT and its nitrate salt. Both are insensitive towards impact and friction and the nitrate salt combines outstanding thermal stability (decomposition temperature=280 °C) with promising calculated energetic values.
Spontaneous Self‐Assembly of γ‐Cyclodextrins in Dilute Solutions with Tunable Sizes and Thermodynamic Stability
Authors: Zhou Jing , Yin Panchao , Gao Yunyi , Hu Lang , Liu Tianbo 
Published: May 2015

AbstractThe behavior in dilute solution of phosphate‐functionalized γ‐cyclodextrin macroanions with eight charges on the rim was explored. The hydrophilic macroions in mixed solvents show strong attraction between each other, mediated by the counterions, and consequently self‐assemble into blackberry‐type hollow spherical structures. Time‐resolved laser light scattering (LLS) measurements at high temperature ruled out the possibility of hydrogen bonding as the main driving force in the self‐assembly and indicated the good thermodynamic stability of assemblies regulated by the charge. The transition from single macroions to blackberries can be tuned by adjusting the content of organic solvent. The sizes of blackberries vary with the charge density of γ‐cyclodextrin by adjusting pH. It is the first report that pure cyclodextrins can generate supramolecular structures by themselves in dilute solution. The unique solution behavior of macroions provides a new opportunity to assemble cyclodextrin into functional materials and devices.
Zinc‐Catalyzed Functionalization of SiH Bonds with 2‐Furyl Carbenoids through Three‐Component Coupling
Authors: Mata Sergio , López Luis A. , Vicente Rubén 
Published: May 2015

AbstractA three‐component coupling of alk‐2‐ynals, 1,3‐dicarbonyls and silanes is reported. ZnCl2 serves as an inexpensive and low‐toxic catalyst for the overall transformation, which involves Knoevenagel condensation, cyclization, and carbene SiH bond insertion. The process takes place with high atom economy in the absence of organic solvents and shows a broad scope. This reaction is also applicable to the functionalization of oligomeric siloxanes.
Directional Dynamic Covalent Motion of a Carbonyl Walker on a Polyamine Track
Authors: Kovaříček Petr , Lehn Jean‐Marie 
Published: May 2015

AbstractInvited for the cover of this issue is the group of Jean‐Marie Lehn at the Université de Strasbourg (France). The image depicts the trend of the research activities pursued in our laboratory in Strasbourg over 50 years towards chemical systems, entities and processes, of increasing complexity. Read the full text of the article at 10.1002/chem.201500987.
ChemInform Abstract: Asymmetric anti‐Selective Michael Reaction of Imidazole‐Modified Ketones with trans‐β‐Nitroalkenes.
Authors: Yang Dongxu , Wang Linqing , Li Dan , Han Fengxia , Zhao Depeng , Wang Rui 
Published: May 2015

AbstractThe highly enantioselective reaction between imidazolyl ketones and nitroalkenes furnishes the anti‐selective adducts in high yields in the presence of a novel bromothiophene‐derived chiral diamine ligand.
Arylamino Esters As P‐Glycoprotein Modulators: SAR Studies to Establish Requirements for Potency and Selectivity
Authors: Teodori Elisabetta , Dei Silvia , Floriddia Elisa , Perrone Maria Grazia , Manetti Dina , Romanelli Maria Novella , Contino Marialessandra , Colabufo Nicola Antonio 
Published: May 2015

AbstractA set of basic aryl‐group‐containing compounds was synthesized with the aim of developing potent and selective P‐glycoprotein (P‐gp) modulators that are able to reverse multidrug resistance (MDR). The natures of the spacer (dicyclohexylamine or dialkylamine) and the aryl moieties were modified to investigate selectivity and the mechanism of P‐gp interaction. The inhibitory activities of the compounds toward P‐gp, multidrug resistance‐associated protein 1 (MRP1), and breast cancer resistance protein (BCRP), the most relevant ATP binding cassette (ABC) transporters for MDR, were evaluated. The mechanism of P‐gp interaction for each compound was investigated with three biological assays: apparent permeability (Papp) determination (B→A/A→B) in Caco‐2 cell monolayers, ATP cell depletion, and inhibition of Calcein‐AM transport in MDCK‐MDR1 cells. These assays allowed us to estimate the selectivity of the compounds for the three efflux pumps and to identify the structural requirements that define the P‐gp‐interaction profile. All dicyclohexylamine derivatives were found to be P‐gp substrates, whereas one dialkylamine derivative was shown to be a P‐gp inhibitor. The good MRP1 activity of one cis/cis isomer highlighted this as a lead candidate for the development of MRP1 ligands.
Evaluation of the expression pattern of rAAV2/1, 2/5, 2/7, 2/8, and 2/9 serotypes with different promoters in the mouse visual cortex
Authors: Scheyltjens Isabelle , Laramée Marie‐Eve , Van den Haute Chris , Gijsbers Rik , Debyser Zeger , Baekelandt Veerle , Vreysen Samme , Arckens Lutgarde 
Published: May 2015

ABSTRACTThis study compared the expression pattern, laminar distribution, and cell specificity of several rAAV serotypes (2/1, 2/5, 2/7, 2/8, and 2/9) injected in the primary visual cortex (V1) of adult C57Bl/6J mice. In order to obtain specific expression in certain neuron subtypes, different promoter sequences were evaluated for excitatory cell specificity: a universal cytomegalovirus (CMV) promoter, and two versions of the excitatory neuron‐specific Ca2+/calmodulin‐dependent kinase subunit α (CaMKIIα) promoter, CaMKIIα 0.4 and CaMKIIα 1.3. The spatial distribution as well as the cell type specificity was immunohistochemically verified. Depending on the rAAV serotype used, the transduced volume expressing reporter protein differed substantially (rAAV2/5 ≫ 2/7 ≈ 2/9 ≈ 2/8 ≫ 2/1). Excitatory neuron‐specific targeting was promoter‐dependent, with a surprising difference between the 1.3 kb and 0.4 kb CaMKIIα promoters. While CaMKIIα 1.3 and CMV carrying vectors were comparable, with 78% of the transduced neurons being excitatory for CMV and 82% for CaMKIIα 1.3, the shorter CaMKIIα 0.4 version resulted in 95% excitatory specificity. This study therefore puts forward the CaMKIIα 0.4 promoter as the best choice to target excitatory neurons with rAAVs. Together, these results can be used as an aid to select the most optimal vector system to deliver transgenes into specific rodent neocortical circuits, allowing further elucidation of their functions. J. Comp. Neurol. 523:2019–2042, 2015. © 2015 Wiley Periodicals, Inc.
Spectroelectrochemical Studies on Quinacridone by Using Poly(vinyl alcohol) Coating as Protection Layer
Authors: Enengl Sandra , Enengl Christina , Stadler Philipp , Neugebauer Helmut , Sariciftci Niyazi Serdar 
Published: May 2015

AbstractSpectroscopic measurements in the infrared range combined with electrochemistry are a powerful technique for investigation of organic semiconductors to track changes during oxidation and reduction (p‐ and n‐doping) processes. For these measurements it is important that the studied material, mostly deposited as a thin film on an internal reflection element, does not dissolve during this characterization. In this study we introduce a technique that allows infrared spectroelectrochemical characterization of films of these materials for the first time. In many cases so far this has been impossible, due to solubility in the oxidized and/or reduced form. This novel technique is shown on thin films of quinacridone by adding a protection layer of poly(vinyl alcohol) (PVA).
Cubic C8: An Observable Allotrope of Carbon?
Authors: Sharapa Dmitry , Hirsch Andreas , Meyer Bernd , Clark Timothy 
Published: May 2015

AbstractAb initio and DFT calculations are used to investigate the structure, electronic properties, spectra and reactivity of cubic C8, which is predicted to be aromatic according to Hirsch′s rule. Although highly strained and with a small amount of diradical character, the carbon cube represents a surprisingly deep minimum and should therefore be observable as an isolated molecule. It is, however, predicted to be very reactive, both with itself and triplet oxygen. Calculated IR, Raman, and UV/Vis spectra are provided to aid identification of cubic C8 should it be synthesized.
Enhancing the Efficiency of Water Oxidation by Boron‐Doped BiVO4 under Visible Light: Hole Trapping by BO4 Tetrahedra
Authors: Li Yanqing , Jing Tao , Liu Yuanyuan , Huang Baibiao , Dai Ying , Zhang Xiaoyang , Qin Xiaoyan , Whangbo Myung‐Hwan 
Published: May 2015

AbstractBoron‐doped monoclinic and tetragonal phases of BiVO4 were prepared by using the urea precipitation method, and the visible‐light photocatalytic activities of pristine and boron‐doped BiVO4 for oxygen generation from water were compared. Boron doping enhances the photocatalytic activities of BiVO4. The reasons for this enhancement were probed by performing X‐ray photoelectron, Raman, and electrochemical impedance spectroscopy measurements, and also by performing density functional calculations for model boron‐doped BiVO4 structures. The photocatalytic activities of BiVO4 is enhanced by boron doping because the resulting BO4 tetrahedra, which are smaller than the VO4 tetrahedra, create an occupied defect level per boron lying approximately 0.17 eV above the valence‐band maximum of pristine BiVO4, and this defect level is localized because it is made up of the O 2 p levels of the BO4 tetrahedron. Thus, the BO4 tetrahedra that result from boron doping act as hole traps, thereby slowing down the recombination of photogenerated electrons and holes.
Affective dysfunction in a mouse model of Rett syndrome: Therapeutic effects of environmental stimulation and physical activity
Authors: Kondo Mari A. , Gray Laura J. , Pelka Gregory J. , Leang Sook‐Kwan , Christodoulou John , Tam Patrick P. L. , Hannan Anthony J. 
Published: May 2015

ABSTRACTRett syndrome (RTT) is a neurodevelopmental disorder associated with mutations in the X‐linked gene encoding methyl‐CpG‐binding protein 2 (MeCP2) and consequent dysregulation of brain maturation. Patients suffer from a range of debilitating physical symptoms, however, behavioral and emotional symptoms also severely affect their quality of life. Here, we present previously unreported and clinically relevant affective dysfunction in the female heterozygous Mecp2tm1Tam mouse model of RTT (129sv and C57BL6 mixed background). The affective dysfunction and aberrant anxiety‐related behavior of the Mecp2+/− mice were found to be reversible with environmental enrichment (EE) from 4 weeks of age. The effect of exercise alone (via wheel running) was also explored, providing the first evidence that increased voluntary physical activity in an animal model of RTT is beneficial for some phenotypes. Mecp2+/− mutants displayed elevated corticosterone despite decreased Crh expression, demonstrating hypothalamic–pituitary–adrenal axis dysregulation. EE of Mecp2+/− mice normalized basal serum corticosterone and hippocampal BDNF protein levels. The enrichment‐induced rescue appears independent of the transcriptional regulation of the MeCP2 targets Bdnf exon 4 and Crh. These findings provide new insight into the neurodevelopmental role of MeCP2 and pathogenesis of RTT, in particular the affective dysfunction. The positive outcomes of environmental stimulation and physical exercise have implications for the development of therapies targeting the affective symptoms, as well as behavioral and cognitive dimensions, of this devastating neurodevelopmental disorder. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 209–224, 2016
Epithelial microRNA‐9a regulates dendrite growth through Fmi‐Gq signaling in Drosophila sensory neurons
Authors: Wang Yan , Wang Huan , Li Xiaoting , Li Yan 
Published: May 2015

ABSTRACTmicroRNA‐9 (miR‐9) is highly expressed in the nervous system across species and plays essential roles in neurogenesis and axon growth; however, little is known about the mechanisms that link miR‐9 with dendrite growth. Using an in vivo model of Drosophila class I dendrite arborization (da) neurons, we show that miR‐9a, a Drosophila homolog of mammalian miR‐9, downregulates the cadherin protein Flamingo (Fmi) thereby attenuating dendrite development in a non‐cell autonomous manner. In miR‐9a knockout mutants, the dendrite length of a sensory neuron ddaE was significantly increased. Intriguingly, miR‐9a is specifically expressed in epithelial cells but not in neurons, thus the expression of epithelial but not neuronal Fmi is greatly elevated in miR‐9a mutants. In contrast, overexpression of Fmi in the neuron resulted in a reduction in dendrite growth, suggesting that neuronal Fmi plays a suppressive role in dendrite growth, and that increased epithelial Fmi might promote dendrite growth by competitively binding to neuronal Fmi. Fmi has been proposed as a G protein‐coupled receptor (GPCR), we find that neuronal G protein Gαq (Gq), but not Go, may function downstream of Fmi to negatively regulate dendrite growth. Taken together, our results reveal a novel function of miR‐9a in dendrite morphogenesis. Moreover, we suggest that Gq might mediate the intercellular signal of Fmi in neurons to suppress dendrite growth. Our findings provide novel insights into the complex regulatory mechanisms of microRNAs in dendrite development, and further reveal the interplay between the different components of Fmi, functioning in cadherin adhesion and GPCR signalling. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 225–237, 2016