bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low‐Temperature Gas‐Phase Oxidation of Benzyl Alcohol on Mesoporous K‐Cu‐TiO2 through Oxidative Dehydrogenation
Authors: Dai Yihu , Yan Xiaoqing , Tang Yu , Liu Xiaonao , Xiao Liping , Fan Jie 
Published: July 2012

AbstractA highly selective, gas‐phase benzyl alcohol‐to‐benzaldehyde transformation is achieved over mesoporous multi‐component metal oxide K‐Cu‐TiO2 (prepared by AcHE process) at a surprisingly low temperature: the b.p. of benzyl alcohol, 203 °C. We propose that highly efficient selective oxidation over K‐Cu‐TiO2 occurs through an oxidative dehydrogenation mechanism based on the catalytic performance with controlled oxygen addition and the observation of surface hydride species on the catalyst surface by electron paramagnetic resonance spectroscopy and spin‐trapping techniques. It was observed that the benzyl alcohol conversion increased sharply with the increase in p and reached a maximum of 80.4 % at p/pBA=0.4–0.6. A further increase in the p slightly decreased the benzyl alcohol conversion. The fact that the reaction rate was independent of the oxygen pressure after the stoichiometric p/pBA ratio (0.5) could indicate a fast reoxidation of CuIH by molecular oxygen, which is, therefore, not the rate‐controlling step. No hydride species have been detected on the catalyst that was collected from the alcohol oxidation reaction performed with added O2, suggesting that O2 acts as efficient hydrogen acceptor and accelerate the reaction by liberating free active CuI sites. Based on understanding of the reaction mechanism, in addition to the low‐temperature reaction condition, stoichiometrical addition of O2 proves effective in the stabilisation of the CuI oxidation state for highly selective benzyl alcohol oxidative dehydrogenation over a wide reaction temperature range (up to 310 °C).
Total Hydrogenation of Furfural over a Silica‐Supported Nickel Catalyst Prepared by the Reduction of a Nickel Nitrate Precursor
Authors: Nakagawa Yoshinao , Nakazawa Hiroya , Watanabe Hideo , Tomishige Keiichi 
Published: July 2012

AbstractGas‐phase hydrogenation of furfural to tetrahydrofurfuryl alcohol is catalyzed by Ni/SiO2 with <4 nm Ni particle size, which is prepared by the reduction of supported nickel nitrate. The maximum yield is 94 %. The conversion of furfural to the furfuryl alcohol intermediate is less structure‐sensitive. The subsequent step in which furfuryl alcohol is converted to tetrahydrofurfuryl alcohol is inhibited by the presence of furfural because furfural is more strongly adsorbed onto the catalyst surface than furfuryl alcohol. This step is strongly structure‐sensitive and smaller turnover frequency (TOF) values are observed over Ni/SiO2 catalysts with a larger particle size.
Calix[4]tubes: An Approach to Functionalization
Authors: Puchnin Kirill , Zaikin Pavel , Cheshkov Dmitry , Vatsouro Ivan , Kovalev Vladimir 
Published: July 2012

AbstractAdamantylcalix[4]arenes decorated with ester groups and calix[4]arene tetratosylates were used to prepare a series of calix[4]tubes bearing 3‐methoxycarbonyl‐ and 3‐methoxycarbonylmethyl‐1‐adamantyl units (up to eight) in good yield. These compounds were subjected to further chemical transformations giving a wide set of novel ester‐, acid‐, hydroxy‐, amine‐, and urea‐functionalized calix[4]tubes. Introduction of urea groups into the calixtube core led not only to anion‐targeted receptors, but also provided heteroditopic behavior of the hosts, which enriches the well‐established potassium‐uptake ability of calix[4]tubes.
CuII Ions and the Stilbene–Chroman Hybrid with a Catechol Moiety Synergistically Induced DNA Damage, and Cell Cycle Arrest and Apoptosis of HepG2 Cells: An Interesting Acid/Base‐Promoted Prooxidant Reaction
Authors: Liu Guo‐Yun , Yang Jie , Dai Fang , Yan Wen‐Jing , Wang Qi , Li Xiu‐Zhuang , Ding De‐Jun , Cao Xiao‐Yan , Zhou Bo 
Published: July 2012

AbstractDevelopment of potential cancer treatment strategies by using an exogenous reactive oxygen species (ROS)‐generating agent (prooxidant) or redox intervention, has attracted much interest. One effective ROS generation method is to construct a prooxidant system by polyphenolic compounds and CuII ions. This work demonstrates that CuII and the stilbene–chroman hybrid with a catechol moiety could synergistically induce pBR322 plasmid DNA damage, as well as cell cycle arrest and apoptosis of HepG2 cells. Additionally, an interesting acid/base‐promoted prooxidant reaction was found. The detailed chemical mechanisms for the reaction of the hybrid with CuII in acid, neutral and base solutions are proposed based on UV/Vis spectral changes and identification of the related oxidative intermediates and products.
Cheap and Long‐Life Reusable Polymer for Asymmetric Organozinc Catalysis Based on Camphor‐Derived Hydroxyamides
Authors: de Las Casas Engel Tomás , Sánchez‐carnerero Esther M. , Sokolovskaya Ekaterina , Gallardo‐araya Claudio M. , JimÉnez Florencio Moreno , Maroto Beatriz Lora , de la Moya Cerero Santiago 
Published: July 2012

ABSTRACTPolystyrene grafted with a chiral zinc‐complexing camphor‐derivedN,N‐disubstituted hydroxyamide is proposed as a new type of functional polymer of high reusability for the development of sustainable organozinc‐catalyzed asymmetric reactions. The main goal of this new functional polymer is the ease of the hydroxyamide‐moiety preparation (cheap chiral ligand obtained straightforwardly from an enantiopure starting material coming from the chiral pool), as well as its chemical robustness when compared with other related zinc‐complexing functional groups. The latter allows the polymer to be active after multiple applications, without significant loss of its catalytic activity. This fact is exemplified by the design and preparation of a polymer functionalized with a bis(hydroxyamide) proved previously as active in the homogeneous enantioselective addition of diethylzinc to aldehydes. The result is a cheap functional polymer with a very high reusability (the enantioselectivity and chemical yield are maintained practically constant after 20 applications). Additionally, a methodology for the multicycle use of these functional polymers is presented.Chirality, 2012. © 2012 Wiley Periodicals, Inc.
Synthesis and Antifungal Activities of New Type β‐Methoxyacrylate‐Based Strobilurin Analogues
Authors: Zhang Xiang , Liu Huijun , Gao Yongxin , Wang Huili , Guo Baoyuan , Li Jianzhong 
Published: July 2012

AbstractStrobilurins have become one of the most important classes of agricultural fungicides. To discover new strobilurin derivatives with high activity against resistant pathogens, a series of novel β‐methoxyacrylate analogues were designed and synthesized by integrating substituted pyrimidine with a strobilurin pharmacophore. The compounds were confirmed and characterized by infrared, 1H nuclear magnetic resonance, elemental analysis and mass spectroscopy. The bioassays indicated that most of the compounds 1 exhibited potent antifungal activity against Colletotrichum orbiculare, Botrytis cinerea Pers and Phytophthora capsici Leonian at the concentration of 50 μg/mL. Exhilaratingly, compound 1a (R=methyl) showed better antifungal activity against all the tested fungi than the commercial strobilurin fungicide azoxystrobin.
Recent Advances in Neuraminidase Inhibitor Development as Anti‐influenza Drugs
Authors: Feng Enguang , Ye Deju , Li Jian , Zhang Dengyou , Wang Jinfang , Zhao Fei , Hilgenfeld Rolf , Zheng Mingyue , Jiang Hualiang , Liu Hong 
Published: July 2012

AbstractThe recent emergence of the highly pathogenic H5N1 subtype of avian influenza virus (AIV) and of the new type of human influenza A (H1N1) have emphasized the need for the development of effective anti‐influenza drugs. Presently, neuraminidase (NA) inhibitors are widely used in the treatment and prophylaxis of human influenza virus infection, and tremendous efforts have been made to develop more potent NA inhibitors to combat resistance and new influenza viruses. In this review, we discuss the structural characteristics of NA catalytic domains and the recent developments of new NA inhibitors using structure‐based drug design strategies. These drugs include analogues of zanamivir, analogues of oseltamivir, analogues of peramivir, and analogues of aromatic carboxylic acid and present promising options for therapeutics or leads for further development of NA inhibitors that may be useful in the event of a future influenza pandemic.
BRCA1, TP53, and CHEK2 germline mutations in uterine serous carcinoma
Authors: Pennington Kathryn P. , Walsh Tom , Lee Ming , Pennil Christopher , Novetsky Akiva P. , Agnew Kathy J. , Thornton Anne , Garcia Rochelle , Mutch David , King Mary‐Claire , Goodfellow Paul , Swisher Elizabeth M. 
Published: July 2012

AbstractBACKGROUND:Uterine serous carcinoma (USC) is not recognized as part of any defined hereditary cancer syndrome, and its association with hereditary breast and ovarian carcinoma and Lynch syndrome are uncertain.METHODS:Using targeted capture and massively parallel genomic sequencing, 151 subjects with USC were assessed for germline mutations in 30 tumor suppressor genes, including BRCA1 (breast cancer 1, early onset), BRCA2, the DNA mismatch repair genes (MLH1 [mutL homolog 1], MSH2 [mutS homolog 2], MSH6, PMS2 [postmeiotic segregation increased 2]), TP53 (tumor protein p53), and 10 other genes in the Fanconi anemia–BRCA pathway. Ten cases with < 10% serous histology were also assessed.RESULTS:Seven subjects (4.6%) carried germline loss‐of‐function mutations: 3 subjects (2.0%) with mutations in BRCA1, 2 subjects (1.3%) with mutations in TP53, and 2 subjects (1.3%) with mutations in CHEK2 (checkpoint kinase 2). One subject with < 10% serous histology had an MSH6 mutation. Subjects with MSH6 and TP53 mutations had neither personal nor family histories suggestive of Lynch or Li‐Fraumeni syndromes. Of the 22 women with USC and a personal history of breast carcinoma, the frequency of BRCA1 mutations was 9%, compared to 0.9% in 119 women with no such history.CONCLUSIONS:Approximately 5% of women with USC have germline mutations in 3 different tumor suppressor genes: BRCA1, CHEK2, and TP53. Mutations in DNA mismatch repair genes that cause Lynch syndrome are rare in USC. The germline BRCA1 mutation rate in USC subjects of 2% is higher than expected in a nonfounder population, suggesting that USC is associated with hereditary breast and ovarian carcinoma in a small proportion of cases. Women with USC and breast cancer should be offered genetic testing for BRCA1 and BRCA2 mutations. Cancer 2013. © 2012 American Cancer Society.
Gene expression‐based chemical genomics identifies heat‐shock protein 90 inhibitors as potential therapeutic drugs in cholangiocarcinoma
Authors: Chen Ming‐Huang , Lin Kun‐Ju , Yang Wu‐Lung R. , Kao Ya‐Wen , Chen Tsung‐Wen , Chao Shu‐Chaou , Chang Peter Mu‐Hsin , Liu Chun‐Yu , Tzeng Cheng‐Hwai , Chao Yee , Chen Ming‐Han , Yeh Chun‐Nan , Huang Chi‐Ying F. 
Published: July 2012

AbstractBACKGROUND.Cholangiocarcinoma (CCA) is an aggressive tumor with a poor prognosis. There is no standard therapy for CCA, and novel drugs for treating refractory CCA need to be identified.METHODS.The authors hypothesized that, if a drug could reverse the gene expression signature of CCA, then it may inhibit the carcinogenesis of CCA and, hence, would be a potential therapeutic agent. Thus, the gene expression signatures from patients with CCA were queried using the bioinformatic method Connectivity Map, resulting in the enrichment of heat‐shock protein 90 (HSP90) inhibitors with therapeutic potentials.RESULTS.Two HSP90 inhibitors, 17‐AAG (tanespimycin) and the synthetic diarylisoxazole amide resorcinol NVP‐AUY922, demonstrated potent antiproliferative activity in in vitro studies. In a thioacetamide‐induced animal model, NVP‐AUY922 also had antitumor activity and resulted in objective tumor regression. In addition, NVP‐AUY922 reduced the expression of client oncoproteins involved in CCA oncogenesis and inhibited downstream proteins of both the phosphatidylinositol 3‐kinase catalytic subunit α/v‐akt murine thymoma viral oncogene homolog 1 protein kinase (PIK3/AKT) pathway and the v‐Ki‐ras2 Kirsten rat sarcoma viral oncogene/mitogen‐activated protein kinase (KRAS/MAPK) pathway.CONCLUSIONS.Preclinical data from the current study suggest that NVP‐AUY922 may be an effective treatment option for patients with CCA. Cancer 2013. © 2012 American Cancer Society.
Parallel computing strategies in the analysis of the inhibiting effect of price limits on futures prices
Authors: Balakrishnan Narayanaswamy , Gopinatha Jakadeesan , Goswami Dhrubajyoti , Shanker Latha 
Published: July 2012

ABSTRACTIn futures markets with price limits, trading halts are triggered by limit hits. Limit hits are rarely observed, perhaps because traders avoid bid‐ask quotes that cause them. If this explanation is true, futures prices would cluster in a narrow region close to the limits. We test this empirically for currency futures contracts and find results consistent with the explanation. The tests require calculations of all combinations of a computationally intensive time series, which are extremely time consuming on a sequential machine and hence limit the practicality of the analysis. Consequently, we investigate parallel computing strategies in partitioning the datasets and solving them in parallel on a high‐end Beowulf cluster. We discuss two different partitioning strategies of the given datasets on the cluster and elaborate the results. Copyright © 2012 John Wiley & Sons, Ltd.
Photophysical and Electrochemical Properties, and Molecular Structures of Organic Dyes for Dye‐Sensitized Solar Cells
Authors: Ooyama Yousuke , Harima Yutaka 
Published: July 2012

AbstractDye‐sensitized solar cells (DSSCs) based on organic dyes adsorbed on oxide semiconductor electrodes, such as TiO2, ZnO, or NiO, which have emerged as a new generation of sustainable photovoltaic devices, have attracted much attention from chemists, physicists, and engineers because of enormous scientific interest in not only their construction and operational principles, but also in their high incident‐solar‐light‐to‐electricity conversion efficiency and low cost of production. To develop high‐performance DSSCs, it is important to create efficient organic dye sensitizers, which should be optimized for the photophysical and electrochemical properties of the dyes themselves, with molecular structures that provide good light‐harvesting features, good electron communication between the dye and semiconductor electrode and between the dye and electrolyte, and to control the molecular orientation and arrangement of the dyes on a semiconductor surface. The aim of this Review is not to make a list of a number of organic dye sensitizers developed so far, but to provide a new direction in the epoch‐making molecular design of organic dyes for high photovoltaic performance and long‐term stability of DSSCs, based on the accumulated knowledge of their photophysical and electrochemical properties, and molecular structures of the organic dye sensitizers developed so far.
Adsorption Features of Flavonoids on Macroporous Adsorption Resins Functionalized with Ionic Liquids
Authors: Lou Song , Di Duolong 
Published: July 2012

AbstractA series of macroporous adsorption resins (MARs) with novel structures is synthesized via Friedel–Crafts catalyzed reaction. The adsorption kinetics of the synthetic resins with respect to the purification effect is systematically investigated by means of the response surface methodology (RSM). The kinetic data cannot be fitted to the classical model because it does not take multicompartments and desorption rates into consideration. A new multicompartment louver‐tide theory is thus developed considering that adsorption is an indefinite dynamic equilibrium process, which can be divided into innumerable ingredients with different desorption rates. This theory produces much better fits to the experimental data and provides a quantitative explanation with multicompartments and adsorption/desorption rates.
Biomass‐Based Polyols through Oxypropylation Reaction
Authors: Aniceto José P. S. , Portugal Inês , Silva Carlos M. 
Published: July 2012

AbstractBiomass residues are a potential renewable source for the sustainable production of chemicals, materials, fuels, and energy embodying the so‐called biorefinery concept. In this context, agro‐forestry and agro‐food industry by‐products have attracted considerable interest of researchers in academia and industry as a renewable source of polymeric materials. The research developed to date on the valorization of biomass residues by converting them into polyols through oxypropylation is the subject of this review. These bio‐based polyols exhibit properties similar to their petrochemical counterparts and, as such, can be used with economical advantage in the production of polyurethanes. The operating conditions of the oxypropylation reaction depend on the biomass and on the desired polyol properties. The discussion of their influence and the economic viability of the process are also presented.
An ID‐based mutual authentication with key agreement protocol for multiserver environment on elliptic curve cryptosystem
Authors: Han Weiwei , Zhu Zhian 
Published: July 2012

SUMMARYMutual authentication is used to validate the legitimacy of a remote login user and a server. Conventional user authentication protocols are suited to solve the privacy and security problems for the single client/server architecture environment. However, the use of computer networks and information technology has grown spectacularly. More and more network architectures are used in multi‐server environments. Recently, several authentication schemes for multi‐server environments have been proposed. However, the performance of these schemes is not suitable for applications. To improve the performance, we propose a new ID‐based mutual authentication protocols for multi‐server environment without bilinear pairings. We also show that the proposed scheme is provable secure in the random oracle model. Copyright © 2012 John Wiley & Sons, Ltd.
Abnormally high digestive enzyme activity and gene expression explain the contemporary evolution of a Diabrotica biotype able to feed on soybeans
Authors: Curzi Matías J. , Zavala Jorge A. , Spencer Joseph L. , Seufferheld Manfredo J. 
Published: July 2012

AbstractWestern corn rootworm (Diabrotica virgifera) (WCR) depends on the continuous availability of corn. Broad adoption of annual crop rotation between corn (Zea mays) and nonhost soybean (Glycine max) exploited WCR biology to provide excellent WCR control, but this practice dramatically reduced landscape heterogeneity in East‐central Illinois and imposed intense selection pressure. This selection resulted in behavioral changes and “rotation‐resistant” (RR) WCR adults. Although soybeans are well defended against Coleopteran insects by cysteine protease inhibitors, RR‐WCR feed on soybean foliage and remain long enough to deposit eggs that will hatch the following spring and larvae will feed on roots of planted corn. Other than documenting changes in insect mobility and egg laying behavior, 15 years of research have failed to identify any diagnostic differences between wild‐type (WT)‐ and RR‐WCR or a mechanism that allows for prolonged RR‐WCR feeding and survival in soybean fields. We documented differences in behavior, physiology, digestive protease activity (threefold to fourfold increases), and protease gene expression in the gut of RR‐WCR adults. Our data suggest that higher constitutive activity levels of cathepsin L are part of the mechanism that enables populations of WCR to circumvent soybean defenses, and thus, crop rotation. These new insights into the mechanism of WCR tolerance of soybean herbivory transcend the issue of RR‐WCR diagnostics and management to link changes in insect gut proteolytic activity and behavior with landscape heterogeneity. The RR‐WCR illustrates how agro‐ecological factors can affect the evolution of insects in human‐altered ecosystems.
Preparation and Properties of Octadecahedral α‐Fe2O3 Nanoparticles Enclosed by {104} and {112} Facets
Authors: Liu Zhong , Lv Baoliang , Wu Dong , Sun Yuhan , Xu Yao 
Published: July 2012

AbstractOctadecahedral α‐Fe2O3 nanoparticles were hydrothermally synthesized in the presence of formamide. These octadecahedral α‐Fe2O3 nanoparticles have a threefold axis and are enclosed by twelve dominant {112} facets and six {104} facets. In comparison with the {104} facets, the sterically less hindered {112} facets induced the selective adsorption of formamide more easily, which resulted in the gradual increase in the amount of {112} facets by decreasing the amount of {104} facets with increasing formamide. The coercivity (Hc) of these octadecahedral particles increased successively as the aspect ratio (c/a) increased. The sensing capability of these particles toward H2O2 was investigated, and the response currents of the particles dominated by {112} facets showed a linear relationship with a concentration of H2O2 in the range from 40 μM to 6.66 mM in different stages.
1,3‐Diethynylbicyclo[1.1.1]pentane, a Useful Molecular Building Block
Authors: Kaleta Jiří , Nečas Marek , Mazal Ctibor 
Published: July 2012

Abstract1,3‐Diethynylbicyclo[1.1.1]pentane (DEBCP) has been found to be a valuable molecular building block mostly for the synthesis of extended, rigid, rod‐like molecules. With its straightforward linear geometry, DEBCP can be used as a nonconjugated alternative to more frequently used π‐conjugated, rod‐like building blocks. Examples of reactions that introduce DEBCP into larger structures are (1) the reaction of DEBCP lithium acetylides with electrophiles such as TMSCl, CO2, and Ph2PCl, (2) Sonogashira–Hagihara cross‐coupling reactions with aryl or heteroaryl iodides or bromides, and (3) umpolung reactions that afford the corresponding dibromo and diiodo derivatives of DEBCP, which then successfully react with tert‐C‐cuprates derived from p‐ and m‐dicarbadodecaboranes or bicyclopentanes. These umpolung reactions afforded a new class of molecular rods that combine carborane or bicyclo[1.1.1]pentane cages with ethynylene linkers. Many of the DEBCP derivatives were studied by single‐crystal X‐ray diffraction. They form well‐organized arrays of molecular rotors, the DEBCP units, and so can be considered as examples of artificial molecular‐size machines.
Application of a Tenax model to assess bioavailability of PCBs in field sediments
Authors: Mackenbach Elizabeth M. , Jing You , Mills Marc A. , Landrum Peter F. , Lydy Michael J. 
Published: July 2012

Abstract
Bioavailability has been estimated in the past using equilibrium partitioning-based biota-sediment accumulation factors. These values are not always reliable using field-collected sediments, however, likely due to varying amounts of different organic carbons, particularly black carbon, in sediments. Therefore, improving approaches to better evaluate contaminant bioavailability in sediment are needed. In the present study, a literature-based model was constructed that relied on both laboratory-exposed and field-collected oligochaete bioaccumulation data. The model system used 24-h Tenax extraction data paired with bioaccumulation tests using oligochaetes to establish the ability and utility of the biomimetic extraction. The model was then tested to confirm its utility and reliability to estimate bioavailability of oligochaetes exposed to polychlorinated biphenyl (PCB) contaminated sediments from the Ottawa River in Ohio, USA. The model correctly identified the bioaccumulation of PCBs for 94.9% of the data and 97% of the dioxin-like congeners. The mono- and di-substituted chlorinated biphenyls were the least well described, but the estimates were conservative, for example, the model overpredicted bioaccumulation. Thus, the Tenax model was robust and reliable across a wide range of sediment characteristics for estimating PCB bioaccumulation in oligochaetes. Environ. Toxicol. Chem. 2012; 31: 2210–2216. © 2012 SETAC