bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cofactor‐Free Light‐Driven Whole‐Cell Cytochrome P450 Catalysis
Authors: Park Jong Hyun , Lee Sahng Ha , Cha Gun Su , Choi Da Som , Nam Dong Heon , Lee Jae Hyung , Lee Jung‐Kul , Yun Chul‐Ho , Jeong Ki Jun , Park Chan Beum 
Published: November 2014

AbstractCytochromes P450 can catalyze various regioselective and stereospecific oxidation reactions of non‐functionalized hydrocarbons. Here, we have designed a novel light‐driven platform for cofactor‐free, whole‐cell P450 photo‐biocatalysis using eosin Y (EY) as a photosensitizer. EY can easily enter into the cytoplasm of Escherichia coli and bind specifically to the heme domain of P450. The catalytic turnover of P450 was mediated through the direct transfer of photoinduced electrons from the photosensitized EY to the P450 heme domain under visible light illumination. The photoactivation of the P450 catalytic cycle in the absence of cofactors and redox partners is successfully conducted using many bacterial P450s (variants of P450 BM3) and human P450s (CYPs 1A1, 1A2, 1B1, 2A6, 2E1, and 3A4) for the bioconversion of different substrates, including marketed drugs (simvastatin, lovastatin, and omeprazole) and a steroid (17β‐estradiol), to demonstrate the general applicability of the light‐driven, cofactor‐free system.
Organic Donor–Acceptor Assemblies form Coaxial p–n Heterojunctions with High Photoconductivity
Authors: Prasanthkumar Seelam , Ghosh Samrat , Nair Vijayakumar C. , Saeki Akinori , Seki Shu , Ajayaghosh Ayyappanpillai 
Published: November 2014

AbstractThe formation of coaxial p–n heterojunctions by mesoscale alignment of self‐sorted donor and acceptor molecules, important to achieve high photocurrent generation in organic semiconductor‐based assemblies, remains a challenging topic. Herein, we show that mixing a p‐type π gelator (TTV) with an n‐type semiconductor (PBI) results in the formation of self‐sorted fibers which are coaxially aligned to form interfacial p–n heterojunctions. UV/Vis absorption spectroscopy, powder X‐ray diffraction studies, atomic force microscopy, and Kelvin‐probe force microscopy revealed an initial self‐sorting at the molecular level and a subsequent mesoscale self‐assembly of the resulted supramolecular fibers leading to coaxially aligned p–n heterojunctions. A flash photolysis time‐resolved microwave conductivity (FP‐TRMC) study revealed a 12‐fold enhancement in the anisotropic photoconductivity of TTV/PBI coaxial fibers when compared to the individual assemblies of the donor/acceptor molecules.
Giving and sharing in the computer‐mediated economy
Authors: Harvey John , Smith Andrew , Golightly David 
Published: November 2014

AbstractThe paper examines how digital technology mediates the behaviour of consumers in three online systems that facilitate offline gift giving and sharing (Freecycle, Couchsurfing, and Landshare). Findings derived from a netnography and depth interviews reveal how technology is used to enact and influence the management of identity, partner selection, ritual normalisation, and negotiation of property rights. The findings have significant implications for the design and management of systems that encourage non‐monetary forms of collaborative consumption. Copyright © 2014 John Wiley & Sons, Ltd.
Rosiglitazone, a PPARγ agonist, ameliorates palmitate‐induced insulin resistance and apoptosis in skeletal muscle cells
Authors: Meshkani Reza , Sadeghi Asie , Taheripak Gholamreza , Zarghooni Maryam , Gerayesh‐Nejad Siavash , Bakhtiyari Salar 
Published: November 2014

Palmitate induces insulin resistance and apoptosis in insulin target tissues. Rosiglitazone (RSG), a peroxisome proliferator‐activated receptor γ (PPARγ) agonist, can activate both pro‐apoptotic and anti‐apoptotic pathways in different cells; however, its effect on palmitate‐induced apoptosis in skeletal muscle cells remains to be elucidated. After differentiation of C2C12 cells, myotubes were treated with palmitate, RSG and GW9662 (PPARγ antagonist). MTT and terminal deoxynucleotide transferase dUTP nick end labelling (TUNEL) assays and caspase‐3 activity were used to investigate the apoptosis. To study the underlying mechanism, glucose uptake, gene expression and protein levels were evaluated. A total of 0.75 mM palmitate reduced cell viability by 43% and increased TUNEL‐positive cells and caspase‐3 activity by 15‐fold and 6.6‐fold, respectively. RSG (10 μM) could markedly decrease the level of TUNEL‐positive cells and caspase‐3 activity in palmitate‐treated cells. The protective effect of RSG on apoptosis was abrogated by GW9662. To investigate the molecular mechanism of this effect, gene expression and protein level of protein tyrosine phosphatase 1B (PTP1B) were evaluated. Palmitate and RSG individually increased the expression and protein level of PTP1B, whereas combined treatment (palmitate and RSG) were able to further increase the expression of PTP1B in C2C12 cells. We also evaluated the effect of RSG on palmitate‐induced insulin resistance in muscle cells. RSG could significantly improve glucose uptake by 0.4‐fold in myotubes treated with palmitate. Moreover, RSG could restore the phosphorylation of Akt in palmitate‐treated cells. These data suggest that RSG protects skeletal muscle cells against palmitate‐induced apoptosis and this effect appears to be mediated via the PPARγ‐dependent and PTP1B‐independent mechanisms. Copyright © 2014 John Wiley & Sons, Ltd.SIGNIFICANCE OF THE STUDYSaturated free fatty acids (FFAs), such as palmitate, have been shown to induce cellular apoptosis. Strategies for preventing the cytotoxic effect of palmitate are useful in reduction of diabetes complications. In this study, we introduced RSG as an agent that protects skeletal muscle cells against palmitate‐induced apoptosis and insulin resistance. It appears that RSG protects skeletal muscle cells against palmitate‐induced apoptosis via the PPARγ‐dependent and PTP1B‐independent mechanisms. Given the role of FFAs in skeletal muscle apoptosis, these findings support the idea that RSG can ameliorate diabetes complications such as skeletal muscle loss.
Enhanced Oxidative Desulfurization of Dibenzothiophene by Functional Mo‐Containing Mesoporous Silica
Authors: Zhang Ming , Zhu Wenshuai , Xun Suhang , Xiong Jun , Ding Wenjing , Li Meng , Wang Qian , Li Huaming 
Published: November 2014

AbstractFunctional mesoporous Mo–SiO2 materials were synthesized by a one‐pot and facile room‐temperature procedure, and characterized by X‐ray diffraction, TEM, Raman spectroscopy, FT‐IR, diffuse reflectance spectra, and BET analysis. The experimental results demonstrated that the mesoporous materials presented a high dispersion of molybdenum species and excellent catalytic activity for the removal of dibenzothiophene (DBT) without organic solvents as extractants. The catalytic performance on different sulfur‐containing compounds was also investigated in detail. After recycling for eight times, the removal of the oxidation desulfurization system could still reach high values. GC‐MS analysis detected the oxidation product of DBT. A mechanism was proposed for the absorptive oxidation process of sulfur compounds.
Modeling, Characteristic Analysis and Optimization of an Improved Heat‐Integrated Air Separation Column
Authors: Chang Liang , Liu Xinggao 
Published: November 2014

AbstractCryogenic air separation as the most important part of an integrated gasification combined cycle is a widely used operation unit for producing large quantities of high‐purity oxygen and nitrogen. However, cryogenic distillation requires a large amount of energy due to the work needed to compress the air feed. An improved heat‐integrated air separation column (HIASC) is proposed. The requirements of high‐purity separation in the industrial cryogenic air separation process are achieved. An optimization model of the heat transfer coefficient (UA), a key parameter in column structure design and operation, is presented. The optimized UA value is obtained within the accepted value range reported in the international open literature, which ensures the practicability of the improved HIASC.
Sorption of Acetaldehyde and Hexanal in Trace Concentrations on Carbon‐Based Adsorbents
Authors: Ortmann Roman , Pasel Christoph , Luckas Michael , Kraas Sebastian , Fröba Michael , Bathen Dieter 
Published: November 2014

AbstractAdsorption processes are frequently applied to separate traces of hazardous and toxic substances from gas streams. Hence, knowledge of sorption characteristics of these substances on standard adsorbents is essential. Sorption of hexanal and acetaldehyde from a nitrogen gas stream in trace concentrations on activated carbon and ordered mesoporous carbon‐based adsorbents (CMK) is studied. A magnetic suspension balance and an attached gaschromatograph‐mass spectrometer were used to analyze the sorption process both gravimetrically and spectrometrically. Both types of adsorbents show a higher capacity for hexanal than acetaldehyde. The activated carbon exhibits considerable differences in regard to desorption of hexanal compared to the mesoporous CMK.
Superior Lithium‐Ion Storage Properties of Si‐Based Composite Powders with Unique Si@Carbon@Void@Graphene Configuration
Authors: Choi Seung Ho , Jung Dae Soo , Choi Jang Wook , Kang Yun Chan 
Published: November 2014

AbstractComposite powders of the configuration Si@carbon@void@graphene were prepared by a one‐step spray pyrolysis process, by adding polyvinylpyrrolidone (PVP) to a precursor solution containing graphene oxide (GO) sheets and silicon nanoparticles (NPs). Morphological analysis indicates that the individual Si NPs are coated with amorphous carbon and encapsulated in a micrometer‐sized graphene ball structure that offers a large amount of buffer space. The addition of PVP improves the stability of the colloidal spray solution containing the GO sheets and the Si NPs. Consequently, the prepared Si@C@void@graphene composite powders have a relatively more uniform morphology than the Si@void@graphene composite powders prepared from the spray solution without PVP. The first charge and discharge capacities of the Si@C@void@graphene electrode measured at 0.1 A g−1 are as high as 3102 and 2215 mA h g−1, respectively. With an increase in the current rate from 0.5 to 11 A g−1, 46 % of the original capacity (i.e., 2134 mA h g−1) is maintained. After 500 cycles at a high rate of 7 A g−1, the Si@C@void@graphene electrode shows 84 % capacity retention and 99.8 % of the average Coulombic efficiency. The superior cycling and rate capabilities of the prepared Si@C@void@graphene electrode could be attributed to the uniform carbon coating of the Si NPs and the graphene ball structure, which facilitates efficient diffusion of Li ions and prevents the penetration of electrolyte into graphene ball during cycling.
Chemically and Electrochemically Triggered Assembly of Viologen Radicals: Towards Multiaddressable Molecular Switches
Authors: Kahlfuss Christophe , Métay Estelle , Duclos Marie‐Christine , Lemaire Marc , Milet Anne , Saint‐Aman Eric , Bucher Christophe 
Published: November 2014

AbstractWe have established that bipyridinium radicals can be reversibly π‐dimerized under the combined effects of chemical (proton transfer) and electrochemical (electron transfer) stimuli. Our investigations also led to the discovery that a bis‐pyridinyl appended calixarene intermediate is involved in a fully reversible redox‐triggered σ‐dimerization process. The structure of the most stable intramolecular σ‐dimer was provided by computational chemistry and its complete conversion into a noncovalent π‐dimer could be triggered chemically by addition of protons, leading to the formation of protonated cation radicals. Theoretical data collected with the N‐methylated and N‐protonated π‐dimers also support the existence of multivariant orientations in π‐bonded dimers of viologen cation‐radicals.
Enhancing Effects of Salt Formation on Catalytic Activity and Enantioselectivity for Asymmetric Hydrogenation of Isoquinolinium Salts by Dinuclear Halide‐Bridged Iridium Complexes Bearing Chiral Diphosphine Ligands
Authors: Kita Yusuke , Yamaji Kenta , Higashida Kosuke , Sathaiah Kandula , Iimuro Atuhiro , Mashima Kazushi 
Published: November 2014

AbstractAsymmetric hydrogenation of 1‐ and 3‐substituted and 1,3‐disubstituted isoquinolinium chlorides using triply halide‐bridged dinuclear iridium complexes [{Ir(H)(diphosphine)}2(μ‐Cl)3]Cl has been achieved by the strategy of HCl salt formation of isoquinolines to afford the corresponding chiral 1,2,3,4‐tetrahydroisoquinolines (THIQs) in high yields and with excellent enantioselectivities after simple basic work‐up. The effects of salt formation have been investigated by time‐course experiments, which revealed that the generation of isoquinolinium chlorides clearly prevented formation of the catalytically inactive dinuclear trihydride complex, which was readily generated in the catalytic reduction of salt‐free isoquinoline substrates. Based on mechanistic investigations, including by 1H and 31P{1H} NMR studies and the isolation and characterization of several intermediates, the function of the chloride anion of the isoquinolinium chlorides has been elucidated, allowing us to propose a new outer‐sphere mechanism involving coordination of the chloride anion of the substrates to an iridium dihydride species along with a hydrogen bond between the chloride ligand and the N‐H proton of the substrate salt.
Optical, Electrochemical, and Magnetic Properties of Pyrrole‐ and Thiophene‐Bridged 5,15‐Diazaporphyrin Dimers
Authors: Omomo Satoshi , Maruyama Yasuhisa , Furukawa Ko , Furuyama Taniyuki , Nakano Haruyuki , Kobayashi Nagao , Matano Yoshihiro 
Published: November 2014

AbstractThe first examples of pyrrole‐ and thiophene‐bridged 5,15‐diazaporphyrin (DAP) dimers are prepared through Stille coupling reactions of nickel(II) and copper(II) complexes of 3‐bromo‐10,20‐dimesityl‐5,15‐diazaporphyrin (mesityl=2,4,6‐trimethylphenyl) with the respective 2,5‐bis(tributylstannyl)heteroles. The effects of the heterole spacers and meso nitrogen atoms on the optical, electrochemical, and magnetic properties of the DAP dimers are investigated by UV/Vis absorption spectroscopy, density functional theory calculations, magnetic circular dichroism spectroscopy, cyclic voltammetry, and EPR spectroscopy. The heterole spacers are found to have a significant impact on the electronic transitions over the entire π‐system. In particular, the pyrrole‐bridged DAP dimers exhibit high light‐harvesting potential in the low‐energy visible/near‐infrared region owing to the intrinsic charge‐transfer character of the lowest excitation.
Thienoacene‐Fused Pentalenes: Syntheses, Structures, Physical Properties and Applications for Organic Field‐Effect Transistors
Authors: Dai Gaole , Chang Jingjing , Shi Xueliang , Zhang Wenhua , Zheng Bin , Huang Kuo‐Wei , Chi Chunyan 
Published: November 2014

AbstractThree soluble and stable thienoacene‐fused pentalene derivatives (1–3) with different π‐conjugation lengths were synthesized. X‐ray crystallographic analysis and density functional theory (DFT) calculations revealed their unique geometric and electronic structures due to the interaction between the aromatic thienoacene units and antiaromatic pentalene moiety. As a result, they all possess a small energy gap and show amphoteric redox behaviour. Time dependent (TD) DFT calculations were used to explain their unique electronic absorption spectra. These new compounds exhibited good thermal stability and ordered packing in solid state and thus their applications in organic field‐effect transistors (OFETs) were also investigated. The highest field‐effect hole mobility of 0.016, 0.036 and 0.001 cm2 V−1 s−1 was achieved for solution‐processed thin films of 1–3, respectively.
Nanoscaled Copper Metal–Organic Framework (MOF) Based on Carboxylate Ligands as an Efficient Heterogeneous Catalyst for Aerobic Epoxidation of Olefins and Oxidation of Benzylic and Allylic Alcohols
Authors: Qi Yue , Luan Yi , Yu Jie , Peng Xiong , Wang Ge 
Published: November 2014

AbstractAerobic epoxidation of olefins at a mild reaction temperature has been carried out by using nanomorphology of [Cu3(BTC)2] (BTC=1,3,5‐benzenetricarboxylate) as a high‐performance catalyst through a simple synthetic strategy. An aromatic carboxylate ligand was employed to furnish a heterogeneous copper catalyst and also serves as the ligand for enhanced catalytic activities in the catalytic reaction. The utilization of a copper metal–organic framework catalyst was further extended to the aerobic oxidation of aromatic alcohols. The shape and size selectivity of the catalyst in olefin epoxidation and alcohol oxidation was investigated. Furthermore, the as‐synthesized copper catalyst can be easily recovered and reused several times without leaching of active species or significant loss of activity.
Integration of grid, cluster and cloud resources to semantically annotate a large‐sized repository of learning objects
Authors: Fabra Javier , Hernández Sergio , Otero Estefanía , Vidal Juan C. , Lama Manuel , Álvarez Pedro 
Published: November 2014

SUMMARYThe Universia repository is composed of more than 15 million of educational resources. The lack of metadata describing these resources complicates their classification, search and recovery. To overcome this drawback, it was decided to semantically annotate the available educational resources using the ADEGA algorithm. For this objective, we selected the DBpedia, a cross‐domain linked data composed of more than 3.77 million ‘things’ with 400 million ‘facts’, in order to make sure that the wide range of Universia topics are covered by the ontology. However, this kind of process is extremely expensive from a computational point of view: more than 1600 years of CPU time was estimated to achieve it. In this paper, parallel programming techniques and distributed computing paradigms are combined in order to achieve this semantic annotation in a reasonable time. The cornerstone of this proposal is a resource management and execution framework able to integrate heterogeneous computing resources at our disposal (grid, cluster and cloud resources). As a result, the problem was solved in less than 180 days, demonstrating that it is perfectly feasible to exploit the advantages of these computing models in the field of linked data. Copyright © 2014 John Wiley & Sons, Ltd.
Distributed wikis: a survey
Authors: Davoust Alan , Skaf‐Molli Hala , Molli Pascal , Esfandiari Babak , Aslan Khaled 
Published: November 2014

Summary‘Distributed wiki’ is a generic term covering various systems, including ‘peer‐to‐peer wiki’, ‘mobile wiki’, ‘offline wiki’, ‘federated wiki’ and others. Distributed wikis distribute their pages among the sites of autonomous participants to address various motivations, including high availability of data, new collaboration models and different viewpoints of subjects. Although existing systems share some common basic concepts, it is often difficult to understand the specificity of each one, the underlying complexities or the best context in which to use it. In this paper, we define, classify and characterize distributed wikis. We identify three classes of distributed wiki systems, each using a different collaboration model and distribution scheme for its pages: highly available wikis, decentralized social wikis and federated wikis. We classify existing distributed wikis according to these classes. We detail their underlying complexities and social and technical motivations. We also highlight some directions for research and opportunities for new systems with original social and technical motivations. Copyright © 2014 John Wiley & Sons, Ltd.
Detection of repackaged mobile applications through a collaborative approach
Authors: Aldini Alessandro , Martinelli Fabio , Saracino Andrea , Sgandurra Daniele 
Published: November 2014

SummaryRepackaged applications are based on genuine applications, but they subtlety include some modifications. In particular, trojanized applications are one of the most dangerous threats for smartphones. Malware code may be hidden inside applications to access private data or to leak user credit. In this paper, we propose a contract‐based approach to detect such repackaged applications, where a contract specifies the set of legal actions that can be performed by an application. Current methods to generate contracts lack information from real usage scenarios, thus being inaccurate and too coarse‐grained. This may result either in generating too many false positives or in missing misbehaviors when verifying the compliance between the application and the contract. In the proposed framework, application contracts are generated dynamically by a central server merging execution traces collected and shared continuously by collaborative users executing the application. More precisely, quantitative information extracted from execution traces is used to define a contract describing the expected application behavior, which is deployed to the cooperating users. Then, every user can use the received contract to check whether the related application is either genuine or repackaged. Such a verification is based on an enforcement mechanism that monitors the application execution at run‐time and compares it against the contract through statistical tests. Copyright © 2014 John Wiley & Sons, Ltd.
Nurr1 blocks the mitogenic effect of FGF‐2 and EGF, inducing olfactory bulb neural stem cells to adopt dopaminergic and dopaminergic‐GABAergic neuronal phenotypes
Authors: Vergaño‐Vera Eva , Díaz‐Guerra Eva , Rodríguez‐Traver Eva , Méndez‐Gómez Héctor R. , Solís Óscar , Pignatelli Jaime , Pickel James , Lee Sang‐Hun , Moratalla Rosario , Vicario‐Abejón Carlos 
Published: November 2014

ABSTRACTThe transcription factor Nurr1 is expressed in the mouse olfactory bulb (OB), although it remains unknown whether it influences the generation of dopaminergic neurons (DA) (DA neurons) in cells isolated from this brain region. We found that expressing Nurr1 in proliferating olfactory bulb stem cells (OBSCs) produces a marked inhibition of cell proliferation and the generation of immature neurons immunoreactive for tyrosine hydroxylase (TH) concomitant with marked upregulations of Th, Dat, Gad, and Fgfr2 transcripts. In long‐term cultures, these cells develop neurochemical and synaptic markers of mature‐like mesencephalic DA neurons, expressing GIRK2, VMAT2, DAT, calretinin, calbindin, synapsin‐I, and SV2. Concurring with the increase in both Th and Gad expression, a subpopulation of induced cells was both TH‐ and GAD‐immunoreactive indicating that they are dopaminergic‐GABAergic neurons. Indeed, these cells could mature to express VGAT, suggesting they can uptake and store GABA in vesicles. Remarkably, the dopamine D1 receptor agonist SKF‐38393 induced c‐Fos in TH+ cells and dopamine release was detected in these cultures under basal and KCl‐evoked conditions. By contrast, cotransducing the Neurogenin2 and Nurr1 transcription factors produced a significant decrease in the number of TH‐positive neurons. Our results indicate that Nurr1 overexpression in OBSCs induces the formation of two populations of mature dopaminergic neurons with features of the ventral mesencephalon or of the OB, capable of responding to functional dopaminergic stimuli and of releasing dopamine. They also suggest that the accumulation of Fgfr2 by Nurr1 in OBSCs may be involved in the generation of DA neurons. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 75: 823–841, 2015