bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Situ Quantification and Visualization of Lithium Transport with Neutrons
Authors: Liu Danny X. , Wang Jinghui , Pan Ke , Qiu Jie , Canova Marcello , Cao Lei R. , Co Anne C. 
Published: July 2014

AbstractA real‐time quantification of Li transport using a nondestructive neutron method to measure the Li distribution upon charge and discharge in a Li‐ion cell is reported. By using in situ neutron depth profiling (NDP), we probed the onset of lithiation in a high‐capacity Sn anode and visualized the enrichment of Li atoms on the surface followed by their propagation into the bulk. The delithiation process shows the removal of Li near the surface, which leads to a decreased coulombic efficiency, likely because of trapped Li within the intermetallic material. The developed in situ NDP provides exceptional sensitivity in the temporal and spatial measurement of Li transport within the battery material. This diagnostic tool opens up possibilities to understand rates of Li transport and their distribution to guide materials development for efficient storage mechanisms. Our observations provide important mechanistic insights for the design of advanced battery materials.
Advancing the Drug Discovery and Development Process
Authors: Nicolaou K. C. 
Published: July 2014

AbstractThe current state of affairs in the drug discovery and development process is briefly summarized and then ways to take advantage of the ever‐increasing fundamental knowledge and technical knowhow in chemistry and biology and related disciplines are discussed. The primary motivation of this Essay is to celebrate the great achievements of chemistry, biology, and medicine and to inform and inspire students and academics to enter the field of drug discovery and development while, at the same time, continue to advance the fundamentals of their disciplines. It is also meant to encourage and catalyze multidisciplinary partnerships between academia and industry as scientists attempt to merge their often complementary interests and expertise to achieve new improvements and breakthroughs in their respective fields, and the common goal of applying them to the discovery and invention of new and better medicines, especially in areas of unmet needs.
A Polyphenylene Support for Pd Catalysts with Exceptional Catalytic Activity
Authors: Wang Feng , Mielby Jerrik , Richter Felix Herrmann , Wang Guanghui , Prieto Gonzalo , Kasama Takeshi , Weidenthaler Claudia , Bongard Hans‐Josef , Kegnæs Søren , Fürstner Alois , Schüth Ferdi 
Published: July 2014

AbstractWe describe a solid polyphenylene support that serves as an excellent platform for metal‐catalyzed reactions that are normally carried out under homogeneous conditions. The catalyst is synthesized by palladium‐catalyzed Suzuki coupling which directly results in formation of palladium nanoparticles confined to a porous polyphenylene network. The composite solid is in turn highly active for further Suzuki coupling reactions, including non‐activated substrates that are challenging even for molecular catalysts.
Enantioselective Formation of Cyano‐Bearing All‐Carbon Quaternary Stereocenters: Desymmetrization by Copper‐Catalyzed N‐Arylation
Authors: Zhou Fengtao , Cheng Gui‐Juan , Yang Wenqiang , Long Yan , Zhang Shasha , Wu Yun‐Dong , Zhang Xinhao , Cai Qian 
Published: July 2014

AbstractThe enantioselective construction of all‐carbon quaternary stereocenters is one of the most challenging fields in asymmetric synthesis. An asymmetric desymmetrization strategy offers an indirect and efficient method for the formation of all‐carbon stereocenters. An enantioselective formation of cyano‐bearing all‐carbon quaternary stereocenters in 1,2,3,4,‐tetrahydroquinolines and 2,3,4,5‐tetrahydro‐1H‐benzo[b]azepines by copper‐catalyzed desymmetric N‐arylation is demonstrated. The cyano group at the prochiral center plays a key role for the high enantioselectivity and works as an important functional group for further transformations. DFT studies provide a model which successfully accounts for the origin of enantioselectivity.
Highly Enantioselective Rhodium(I)‐Catalyzed Carbonyl Carboacylations Initiated by CC Bond Activation
Authors: Souillart Laetitia , Cramer Nicolai 
Published: July 2014

AbstractThe lactone motif is ubiquitous in natural products and pharmaceuticals. The Tishchenko disproportionation of two aldehydes, a carbonyl hydroacylation, is an efficient and atom‐economic access to lactones. However, these reaction types are limited to the transfer of a hydride to the accepting carbonyl group. The transfer of alkyl groups enabling the formation of CC bonds during the ester formation would be of significant interest. Reported herein is such asymmetric carbonyl carboacylation of aldehydes and ketones, thus affording complex bicyclic lactones in excellent enantioselectivities. The rhodium(I)‐catalyzed transformation is induced by an enantiotopic CC bond activation of a cyclobutanone and the formed rhodacyclic intermediate reacts with aldehyde or ketone groups to give highly functionalized lactones.
Statistical analysis of nanofibers alignment in magnetic‐field‐assisted electrospinning including an alignment percentage formula
Authors: Rahmani Shahrzad , Rafizadeh Mehdi , Afshar Taromi Framarz 
Published: July 2014

ABSTRACTMagnetic‐field‐assisted electrospinning (MFAES) is a simple and effective method to align polymer nanofibers. In this method, further research is needed to identify alignment mechanism. Hence, this article includes statistical analysis of affecting factors to investigate alignment mechanism in MFAES. Tip to target distance, magnets distance, voltage, and collection time, which are recognized as the most effective factors on nanofibers alignment, were applied in design of experiments. Central composite method was applied to get required experiments with designed expert 8 software. A response surface was proposed with regression coefficient of 97%. Then, the common physics concepts and statistical results were used to discuss the affecting mechanism of the electric and magnetic fields on the electrospinnig jet and the nanofibers alignment. Field emission scanning electron microscopy images were used to characterize the nanofibers alignment and calculate overall alignment percentage using a proposed statistical combinatorial weighted percentage formula. MFAES method, used in this research, achieved 95.3% polyacrylonitrile‐aligned nanofibers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41179.
Impact of the coating process on the molecular structure of starch‐based barrier coatings
Authors: Menzel Carolin , Koch Kristine 
Published: July 2014

ABSTRACTMolecular analysis of starch structure can be used to explain and predict changes in physical properties, such as water vapor and oxygen barrier properties in packaging materials. Solution casting is a widely used technique to create films from starch formulations. This study compared the molecular properties of these standard films with those of experimental coatings applied to paper in laboratory‐scale and pilot‐scale trials, with all three techniques using the same starch formulation. The results revealed large differences in molecular structure, i.e., cross‐linking and hydrolysis, between films and coatings. The main differences were due to the shorter drying time allowed to laboratory‐scale coatings and the accelerated drying process in pilot trials owing to the high energy output of infrared dryers. Furthermore, surface morphology was highly affected by the coating technique used, with a rougher surface and many pinholes occurring in pilot‐scale coatings, giving lower water vapor permeability than laboratory‐scale coatings. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41190.
Polyaniline nanofibers for In situ MAO‐catalyzed polymerization of ethylene
Authors: de Souza Basso Nara Regina , Oliveira Felipo , Graebin Ana Paula , Moura Cássio Stein , de Carvalho Fim Fabiana , Galland Griselda Barrera , Bonnaud Leila , Murariu Oltea , Dubois Philippe 
Published: July 2014

ABSTRACTIn this work electro‐conductive polyaniline nanofibers (PAni‐nanofibers) were prepared via interfacial methodology. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that the synthesized PAni‐nanofibers present high aspect ratio with an average diameter of 80 nm, while they exhibit high conductivity (DC conductivity values: 4.19 ± 0.21 S cm−1). After specific treatment to remove moisture and remaining trapped HCl from PAni‐nanofibers, it was possible to prepare promising polyethylene (PE)/PAni composites by in situ polymerization of ethylene using bis(cyclopentadienyl) zirconium(IV) dichloride (Cp2ZrCl2) and methylaluminoxane (MAO) as catalytic system. More precisely, various contents of PAni‐nanofibers (from 0.2 to 7 wt %) were successfully incorporated in the in situ produced PE/PAni nanocomposites. PAni‐nanofibers were found to affect significantly the crystallization of the polyolefinic matrix while preserving its thermal stability. Preliminary measurements of electric properties showed PAni‐nanofibres are able to bring electro‐conductive properties to the in situ polymerized PE/PAni composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41197.
Ultrasound assisted continuous‐mixing for the preparation of PP/SEBS/OMMT ternary nanocomposites
Authors: Liu Ying , Xie Linsheng , Ma Yulu , Liu Haitao , Zhao Haili , Wang Yunxiang 
Published: July 2014

ABSTRACTPolypropylene (PP)/polystyrene‐block‐poly(ethylene‐co‐butylenes)‐block‐polystyrene (SEBS)/organo‐montmorillonite (OMMT) nanocomposites of varying concentrations of maleic anhydride‐grafted polypropylene (PP‐g‐MA) were prepared by continuous mixing assisted by ultrasonic oscillation. The structure and morphology of nanocomposites were investigated by X‐ray diffraction (XRD), transmission electron microscopy, and scanning electron microscopy. It was found that both PP‐g‐MA and ultrasonic oscillation could enhance the intercalation and exfoliation of OMMT in PP matrix. Meanwhile, the formation of
PP could be induced by ultrasonic irradiation at a power of more than 540 W. Rheological properties including complex viscosity, storage, and loss modulus of nanocomposites were increased after adding PP‐g‐MA or ultrasonic treatment. The results of mechanical properties showed that PP‐g‐MA could improve the tensile strength and tensile modulus of nanocomposites, but with the sacrifice of impact strength. This problem could be improved by ultrasound due to the reduced particle size of SEBS. However, the mechanical properties would be reduced by ultrasonic treatment with higher intensity due to the polymer degradation. Therefore, the synergistic effect of both compatibilizer and ultrasound should account for the balance between toughness and stiffness of PP/SEBS/OMMT ternary nanocomposites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41202.
Remote Sulfonamido Group Enhances Reactivity and Selectivity for Asymmetric Michael Addition of Nitroalkanes to α,β‐Unsaturated Aldehydes
Authors: Huang Yu‐Chao , Uang Biing‐Jiun 
Published: July 2014

AbstractThe pyrrolidine–camphorsulfonamide‐based catalyst 1 a catalyzes the enantioselective conjugate addition of nitroalkanes to α,β‐unsaturated aldehydes in the presence of five equivalents of water in iPrOH to give the corresponding chiral Michael adducts in good yields and high enantioselectivities (up to 99 % ee) with a catalyst loading as low as 1 mol %.
Targeting cancer's weaknesses (not its strengths): Therapeutic strategies suggested by the atavistic model
Authors: Lineweaver Charles H. , Davies Paul C. W. , Vincent Mark D. 
Published: July 2014

In the atavistic model of cancer progression, tumor cell dedifferentiation is interpreted as a reversion to phylogenetically earlier capabilities. The more recently evolved capabilities are compromised first during cancer progression. This suggests a therapeutic strategy for targeting cancer: design challenges to cancer that can only be met by the recently evolved capabilities no longer functional in cancer cells. We describe several examples of this target‐the‐weakness strategy. Our most detailed example involves the immune system. The absence of adaptive immunity in immunosuppressed tumor environments is an irreversible weakness of cancer that can be exploited by creating a challenge that only the presence of adaptive immunity can meet. This leaves tumor cells more vulnerable than healthy tissue to pathogenic attack. Such a target‐the‐weakness therapeutic strategy has broad applications, and contrasts with current therapies that target the main strength of cancer: cell proliferation.Also watch the Video Abstract.
Preparation of carbon quantum dots based on starch and their spectral properties
Authors: Yan Zhengyu , Shu Juan , Yu Yan , Zhang Zhengwei , Liu Zhen , Chen Jianqiu 
Published: July 2014

AbstractA simple method for the synthesis of water‐soluble carbon quantum dots (CQDs) has been developed based on chemical oxidation of starch. The structures and optical properties of the CQDs were characterized by ultraviolet–visible (UV–Vis) spectroscopy, photoluminescence spectroscopy (PL) and transmission electron microscopy. The CQDs were found to emit bright blue fluorescence and disperse uniformly. The effects of ambient temperature, light and pH on the properties of CQDs were studied. The CQDs exhibited good chemical stability, good photostability and pH sensitivity. Furthermore, the interaction between CQDs and bovine serum albumin (BSA) was investigated. Copyright © 2014 John Wiley & Sons, Ltd.
Electrospun tecophilic/gelatin nanofibers with potential for small diameter blood vessel tissue engineering
Authors: Vatankhah Elham , Prabhakaran Molamma P. , Semnani Dariush , Razavi Shahnaz , Morshed Mohammad , Ramakrishna Seeram 
Published: July 2014

ABSTRACTTissue engineering techniques particularly using electrospun scaffolds have been intensively used in recent years for the development of small diameter vascular grafts. However, the development of a completely successful scaffold that fulfills multiple requirements to guarantee complete vascular regeneration remains challenging. In this study, a hydrophilic and compliant polyurethane namely Tecophilic (TP) blended with gelatin (gel) at a weight ratio of 70:30 (TP(70)/gel(30)) was electrospun to fabricate a tubular composite scaffold with biomechanical properties closely simulating those of native blood vessels. Hydrophilic properties of the composite scaffold induced non‐thrombogenicity while the incorporation of gelatin molecules within the scaffold greatly improved the capacity of the scaffold to serve as an adhesive substrate for vascular smooth muscle cells (SMCs), in comparison to pure TP. Preservation of the contractile phenotype of SMCs seeded on electrospun TP(70)/gel(30) was yet another promising feature of this scaffold. The nanostructured TP(70)/gel(30) demonstrated potential feasibility toward functioning as a vascular graft. © 2014 Wiley Periodicals, Inc. Biopolymers 101: 1165–1180, 2014.
Pharmacokinetic comparisons by UPLC‐MS/MS of isomer paeoniflorin and albiflorin after oral administration decoctions of single‐herb Radix Paeoniae Alba and Zengmian Yiliu prescription to rats
Authors: Gong Can , Yang Hong , Wei Hai , Qi Cong , Wang Chang‐hong 
Published: July 2014

AbstractZengmian Yiliu (ZMYL), a traditional Chinese formula, is designed to improve clinical efficacy and reduce adverse effects in combination with cisplatin in ovarian cancer chemotherapy. In ZMYL, Radix Paeoniae Alba (RPA, made from root of Paeonia lactiflora Pall.) acts as an adjunctive drug in cancer treatment by ameliorating side effects induced by radio‐ and chemotherapy. The pharmacokinetics differences between isomer albiflorin and paeoniflorin, the main components of RPA, after oral administration decoction of single‐herb RPA and ZMYL were compared using a sensitive and accurate UPLC‐MS/MS. The results indicate that there are statistically significant differences between the pharmacokinetic parameters: decreasing area under the plasma concentration–time curve (AUC), maximum concentration (Cmax), elimination rate constant (Ke) and increasing apparent volume of distribution (Vd) and clearance (CL) for albiflorin, increasing distribution half‐life (T1/2d) and decreasing elimination half‐life (T1/2e), distribution rate constant (Kd) and absorption rate constant (Ka) for paeoniflorin in the ZMYL group compared with the single‐herb RPA group. In comparison with albiflorin, the pharmacokinetic parameters of paeoniflorin included significantly increasing mean residence time (MRT) and Vd, decreasing CL and Ke in the single‐herb RPA group and increasing MRT and T1/2d and decreasing CL, Ke and Kd in the ZMYL group. Both paeoniflorin and albiflorin are more likely, as the main active ingredients in RPA and ZMYL, to play a variety of pharmacological effects, and herb–herb interactions occur, resulting in different pharmacokinetics of albiflorin and paeoniflorin in RPA and ZMYL. Copyright © 2014 John Wiley & Sons, Ltd.
Pharmacokinetic study of five ginsenosides using a sensitive and rapid liquid chromatography–tandem mass spectrometry method following single and multiple oral administration of Shexiang Baoxin pills to rats
Authors: Peng Chengcheng , Yang Yongge , Lv Chao , Jin Huizi , Tao Jianfei , Yuan Xing , Huang Huimei , Han Lin , Chang Wanlin , Liu Runhui , Zhang Weidong 
Published: July 2014

AbstractShexiang Baoxin pills (SBP) are a traditional Chinese medicine that are used for treating coronary heart disease. Ginsenosides are the main effective components of SBP, but a comprehensive and deep pharmacokinetic study of ginsenosides in SBP, including multiple dosing and linear or nonlinear properties, is lacking. This study was designed to investigate and compare the pharmacokinetic characteristics of ginsenosides in SBP at a single dose and in multiple doses. A liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method was developed for the simultaneous determination of the ginsenosides Rg1, Re, Rb3, Rc and Rb1 in rat plasma. Rats were randomly assigned to receive a single dose of 4, 8 or 12 g/kg and multiple doses (4 g/kg) of SBP for 8, 15 or 22 consecutive days. The results revealed that ginsenosides, following a single oral dose of 4 or 8 g/kg, were absorbed rapidly, with a Tmax ranging from 0.250 to 1.08 h. The AUC0–t and Cmax of the ppd‐type ginsenosides Rb3, Rc and Rb1 were greater than those of the ppt‐type ginsenosides Rg1 and Re. Nondose‐dependent exposure was observed at doses of 4–12 g/kg for all of the ginsenosides. After multiple dosing, the plasma levels of the ppt‐type ginsenosides decreased, whereas those of the ppd‐type ginsenosides did not change significantly. In conclusion, the LC‐MS/MS method was successfully applied to investigate the pharmacokinetics of ginsenosides after single and multiple oral administrations of SBP. The ginsenosides did not accumulate after multiple dosing. The ppd‐type ginsenosides displayed more favorable pharmacokinetic properties compared with the ppt‐type ginsenosides. Copyright © 2014 John Wiley & Sons, Ltd.
Predicted Incorporation of Non‐native Substrates by a Polyketide Synthase Yields Bioactive Natural Product Derivatives
Authors: Bravo‐Rodriguez Kenny , Ismail‐Ali Ahmed F. , Klopries Stephan , Kushnir Susanna , Ismail Shehab , Fansa Eyad K. , Wittinghofer Alfred , Schulz Frank , Sanchez‐Garcia Elsa 
Published: July 2014

AbstractThe polyether ionophore monensin is biosynthesized by a polyketide synthase that delivers a mixture of monensins A and B by the incorporation of ethyl‐ or methyl‐malonyl‐CoA at its fifth module. Here we present the first computational model of the fifth acyltransferase domain (AT5mon) of this polyketide synthase, thus affording an investigation of the basis of the relaxed specificity in AT5mon, insights into the activation for the nucleophilic attack on the substrate, and prediction of the incorporation of synthetic malonic acid building blocks by this enzyme. Our predictions are supported by experimental studies, including the isolation of a predicted derivative of the monensin precursor premonensin. The incorporation of non‐native building blocks was found to alter the ratio of premonensins A and B. The bioactivity of the natural product derivatives was investigated and revealed binding to prenyl‐binding protein. We thus show the potential of engineered biosynthetic polyketides as a source of ligands for biological macromolecules.
H‐Aggregates of Oligophenyleneethynylene (OPE)‐BODIPY Systems in Water: Guest Size‐Dependent Encapsulation Mechanism and Co‐aggregate Morphology
Authors: Allampally Naveen Kumar , Florian Alexander , Mayoral María José , Rest Christina , Stepanenko Vladimir , Fernández Gustavo 
Published: July 2014

AbstractThe synthesis of a new oligophenyleneethynylene (OPE)‐4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) bolaamphiphile 1 and its aqueous self‐assembly are reported. Compound 1 forms H‐type aggregates in aqueous and polar media, as demonstrated by UV/Vis and fluorescence experiments. Concentration‐dependent 1H NMR studies in CD3CN reveal that the BODIPY units are arranged on top of each other into π‐stacks with H‐type excitonic coupling, as supported by ROESY NMR and theoretical calculations and visualized by Cryo‐SEM studies. A detailed analysis of the spectral changes observed in temperature‐dependent UV/Vis studies reveals that 1 self‐assembles in a non‐cooperative (isodesmic) fashion in water. The hydrophobic interior of these self‐assembled structures can be exploited to encapsulate hydrophobic dyes, such as tetracene and anthracene. Both dyes absorb in a complementary region of the UV/Vis spectrum and are small enough to interact with the hydrophobic segments of 1. Temperature‐dependent UV/Vis studies reveal that the spectral changes associated to the encapsulation mechanism of tetracene can be fitted to a Boltzmann function, and the initially flexible fibres of 1 rigidify upon guest addition. In contrast, the co‐assembly of 1 and anthracene is a highly cooperative process, which suggests that a different class of (more‐ordered) aggregates is formed. TEM and Cryo SEM imaging show the formation of uniform spherical nanoparticles, indicating that a subtle change in the guest molecular structure induces a significant change in the encapsulation mechanism and, consequently, the aggregate morphology.