bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arginine‐Facilitated α‐ and π‐Radical Migrations in Glycylarginyltryptophan Radical Cations
Authors: Song Tao , Ng Dominic C. M. , Quan Quan , Siu Chi‐Kit , Chu Ivan K. 
Published: January 2011

AbstractWe have used model tripeptides GXW (with X being one of the amino acid residues glycine (G), alanine (A), leucine (L), phenylalanine (F), glutamic acid (E), histidine (H), lysine (K), or arginine (R)) to study the effects of the basicity of the amino acid residue on the radical migrations and dissociations of odd‐electron molecular peptide radical cations M.+ in the gas phase. Low‐energy collision‐induced dissociation (CID) experiments revealed that the interconvertibility of the isomers [G.XW]+ (radical centered on the N‐terminal α‐carbon atom) and [GXW].+ (radical centered on the π system of the indolyl ring) generally increased upon increasing the proton affinity of residue X. When X was arginine, the most basic amino acid, the two isomers were fully interconvertible and produced almost identical CID spectra despite the different locations of their initial radical sites. The presence of the very basic arginine residue allowed radical migrations to proceed readily among the [G.RW]+ and [GRW].+ isomers prior to their dissociations. Density functional theory calculations revealed that the energy barriers for isomerizations among the α‐carbon‐centered radical [G.RW]+, the π‐centered radical [GRW].+, and the β‐carbon‐centered radical [GRWβ.]+ (ca. 32–36 kcal mol−1) were comparable with those for their dissociations (ca. 32–34 kcal mol−1). The arginine residue in these GRW radical cations tightly sequesters the proton, thereby resulting in minimal changes in the chemical environment during the radical migrations, in contrast to the situation for the analogous GGW system, in which the proton is inefficiently stabilized during the course of radical migration.
Investigation on the analytical application of cationic Gemini surfactant 12‐4‐12 and its interaction with DNA
Authors: He Yu , Sheng Lijiao , Li Ling , Song Gongwu 
Published: January 2011

ABSTRACTThe quantitative determination of nucleic acids is of great importance in fundamental research and clinical diagnosis. In this work, the interaction between DNA and cationic Gemini surfactant 12‐4‐12, which changes the conformation of DNA, was investigated by UV‐vis absorption, FT‐IR spectra and steady‐state fluorescence techniques. A hydrophobic pyrene probe was used to investigate the microenvironment change and calculate the critical micelle concentration (CMC) of Gemini surfactant 12‐4‐12 (0.69 mmol/L), which is close to the value obtained from the conductivity method (0.79 mmol/L). A new detection assay for DNA is proposed with Gemini surfactant 12‐4‐12, using the resonance light‐scattering (RLS) technique. The formation of DNA–12‐4‐12 complex resulted in enhanced RLS signals at 368 nm, which is proportional to DNA concentration in the range 0.304–5.32 mg/L, with a detection limit of 35 µg/L. Most coexisting substances do not interfere in the detection and four synthetic samples were analyzed satisfactorily. Copyright © 2011 John Wiley & Sons, Ltd.
Interaction of β‐cyclodextrin‐capped CdSe quantum dots with inorganic anions and cations
Authors: Shang Zhuo Bin , Hu Shuang , Wang Yu , Jin Wei Jun 
Published: January 2011

ABSTRACTA facile method was developed for the preparation of water soluble β‐Cyclodextrin (β‐CD)‐modified CdSe quantum dots (QDs) (β‐CD‐QDs) by directly replacing the oleic acid ligands on the QDs surface with β‐CD in an alkaline aqueous solution. The as‐prepared QDs show good stability in aqueous solution for several months. Oxoanions, including phosphoric acid ion, sulphite acid ion and carbonic acid ion, affect the fluorescence of β‐CD‐QDs. Among them, H2PO4– exhibited the largest quenching effect. For the polyprotic acids (HO)3AO, the effect of acidic anions on the fluorescence of β‐CD‐QDs was in the order: monoanion (HO)2AO2– > dianion (HO)AO32– >> trianion AO43–. After photoactivation for several days in the presence of anions at alkaline pH, the β‐CD‐QDs exhibited strong fluorescence emission. The effect of various heavy and transition metal ions on the fluorescence properties of the β‐CD‐QDs was investigated further. It was found that Ag+, Hg2+ and Co2+ have significant quenching effect on the fluorescence of the β‐CD‐QDs. The Stern–Volmer quenching constants increased in the order: Hg2+ < Co2+ <Ag+. The adsorption model of metal ions on β‐CD‐QDs was explored. Copyright © 2011 John Wiley & Sons, Ltd.
A hevein‐like protein and a class I chitinase with antifungal activity from leaves of the paper mulberry
Authors: Zhao Ming , Ma Yan , Pan Ying‐Hong , Zhang Chun‐Hua , Yuan Wen‐Xia 
Published: January 2011

AbstractPaper mulberry (Broussonetia papyrifera, syn. Morus papyrifera L.) is a Chinese traditional medicine and its low‐molecular‐weight extracts are reported to have antifungal activity. In this study, two proteins (PMAPI and PMAPII) with activity against Trichoderma viride were obtained from paper mulberry leaves with a fast protein liquid chromatography (FPLC) unit. The purification protocol employed (NH4)2SO4 precipitation, ion‐exchange chromatography and hydrophobic‐interaction chromatography on FPLC. Molecular masses were 18,798 Da for PMAPI, and 31,178 Da for PMAPII determined by Matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry. Peptide mapping fingerprint analysis showed that PMAPI has no peptides similar to PMAPII. N‐terminal amino acid sequencing revealed that PMAPI is a hevein‐like protein, and PMAPII is a class I chitinase. They both had a half‐maximal inhibitory concentration (IC50) of 0.1 µg/µL against T. viride. This is the first report of high‐molecular‐weight extracts with antifungal activity from paper mulberry. Copyright © 2011 John Wiley & Sons, Ltd.
Development and validation of a highly sensitive LC‐MS/MS method for simultaneous quantitation of ethionamide and ethionamide sulfoxide in human plasma: application to a human pharmacokinetic study
Authors: Deshpande Abhijeet Y. , Gurav Sandip , Punde Ravindra , Zambre Vishal , Kulkarni Rahul , Pandey Sarvesh , Mungantiwar Ashish , Mullangi Ramesh 
Published: January 2011

AbstractA highly sensitive and specific LC‐MS/MS method has been developed for simultaneous quantification of ethionamide and ethionamide sulfoxide in human plasma (300 µL) using prothionamide as an internal standard (IS). Solid‐phase extraction was used to extract ethionamide, ethionamide sulfoxide and IS from human plasma. The chromatographic separation of ethionamide, ethionamide sulfoxide and IS was achieved with a mobile phase consisting of 0.1% acetic acid : acetonitrile (20:80, v/v) at a flow rate of 0.50 mL/min on a Peerless Basic C18 column. The total run time was 3.5 min and the elution of ethionamide, ethionamide sulfoxide and IS occurred at 2.50, 2.18 and 2.68 min, respectively. A linear response function was established for the range of concentrations 25.7–6120 ng/mL (r > 0.998) for ethionamide and 50.5–3030 ng/mL (r > 0.998) for ethionamide sulfoxide. The intra‐ and inter‐day precision values for ethionamide and ethionamide sulfoxide met the acceptance as per FDA guidelines. Ethionamide and ethionamide sulfoxide were stable in battery of stability studies, viz. bench‐top, autosampler and freeze–thaw cycles. The developed assay was applied to a pharmacokinetic study in humans. Copyright © 2011 John Wiley & Sons, Ltd.
Simultaneous estimation of E‐ and Z‐isomers of guggulsterone in rabbit plasma using liquid chromatography tandem mass spectrometry and its application to pharmacokinetic study
Authors: Bhatta R. S. , Kumar D. , Chhonker Y. S. , Jain G. K. 
Published: January 2011

AbstractA sensitive and selective liquid chromatography/tandem mass spectrometric method was developed for simultaneous determination of E‐ and Z‐guggulsterone isomers (antihyperlipidemic drug) in rabbit plasma. Both the isomers were resolved on a Symmetry‐Shield C18 (5 µm, 4.6 × 150 mm) column, using gradient elution comprising a mobile phase of methanol, 0.5% v/v formic acid and acetonitrile. With dexamethasone as internal standard, plasma samples were extracted by an automated solid‐phase extraction method using C18 cartridges. Detection was performed by electrospray ionization in multiple reaction monitoring (MRM) in positive mode. The calibration curve was linear over the concentration range of 1.56–200 ng/mL (r2 ≥ 0.998) for both analytes. The intra‐day and inter‐day accuracy and precision were within −0.96 to 4.12 (%bias) and 2.73 to 8.00 (%RSD) respectively. The analytes were stable after three freeze–thaw cycles. The method was successfully applied to study steriospecific pharmacokinetics of E‐ and Z‐guggulsterone in NZ rabbit. Copyright © 2011 John Wiley & Sons, Ltd.
Brand names on packaging and their impact on purchase preference
Authors: Laforet Sylvie 
Published: January 2011

AbstractThis study examines whether appearance of corporate, product and dual brand names (or a combination of brand names used together) on packaging influence consumer purchase preference. The face‐to‐face survey consists of consumers rating their purchase preference on a 7‐point scale sixteen random brand names, and combinations of brand names on packaging along with three different prices, each for two product categories: chocolate and cereals – a total of 4032 observations are examined. Hypotheses are tested using multiple linear regression models. The findings show corporate, product and dual brand names have little impact on purchase preference per se, instead brand category dominance influence consumer choice, and corporate names do not add value as previously thought. The study suggests trends and contexts in which, a corporate name and a product brand name may be extended to optimise consumer brand associations and influence purchase, as well as strategies for extending in remote product categories. Future research needs focusing on international consumers' response on brand linkages in the international arena, and the issues of brand building and brand equity maintenance in international markets. The study makes contribution to brand extension, brand portfolio management and strategic brand management research. Copyright © 2011 John Wiley & Sons, Ltd.
The effect of usage situation on Korean consumers' brand evaluation: The moderating role of self‐monitoring
Authors: Sung Yongjun 
Published: January 2011

AbstractThe objective of this research is to test the theoretical conceptualizations of the self – the malleable self‐concept – by examining the interplay of brand personality and social situation in determining brand preference and evaluation. This research also aims to assess the moderating influence of self‐monitoring in the relationship. Two experimental studies were conducted in Korea. Findings suggest that the congruency of brand personality traits and social situations leads to a more positive brand attitude. This research also supported theory‐based interactions in which situation congruity was enhanced for high versus low self‐monitors. Copyright © 2011 John Wiley & Sons, Ltd.
Metaphoric advertisement comprehension: The role of the cerebral hemispheres
Authors: Vance Kristy , Virtue Sandra 
Published: January 2011

AbstractCurrently little is known about how implicit processes (i.e., cognitive processes that consumers are unaware of) are utilized as consumers read metaphoric advertisements. The field of cognitive neuroscience can help marketers better understand consumers' implicit processing by examining how each cerebral hemisphere uniquely contributes during metaphoric advertisement comprehension. A right hemisphere advantage has been demonstrated during metaphoric language processing; however, it is unclear how each hemisphere of the brain processes metaphors used in advertisements. This study combines the fields of marketing and cognitive neuroscience to investigate the hemispheric processing of metaphoric advertisements. Through the use of the divided visual field paradigm, participants read metaphor, literal, or neutral slogans and responded to related target words presented to either the left visual field‐right hemisphere or the right visual field‐left hemisphere. As predicted, there was a right hemisphere advantage, compared to the left hemisphere, for metaphoric slogans. Additionally, greater facilitation was evident in the right hemisphere for literal slogans compared to metaphoric slogans. Metaphoric messages were also remembered better than literal ones. These findings provide an in‐depth account of how consumers implicitly process messages, suggesting an important role of the right hemisphere during the comprehension of both metaphoric and literal messages. Copyright © 2011 John Wiley & Sons, Ltd.
Exploring consumer adoption of a high involvement eco‐innovation using value‐belief‐norm theory
Authors: Jansson Johan , Marell Agneta , Nordlund Annika 
Published: January 2011

AbstractEnvironmental problems are increasingly becoming everyday issues of international organizations, national governments, and individual consumers. In consumer behavior research considerable effort has been focused on understanding environmentally significant behaviors. One such research stream uses the value‐belief‐norm theory (VBN) to explain and predict a number of relatively low involvement proenvironmental consumer behaviors such as household energy use. However, many consumer behaviors with significant impact on the environment are categorized as high involvement behaviors where VBN theory has not yet been employed. The aim of this paper is to arrive at a better understanding of consumer adoption of a high involvement eco‐innovation using VBN theory. As an example of a high involvement eco‐innovation the alternative fuel vehicle (AFV) which runs on fossil oil‐alternative fuels such as electricity and biofuels is used. A representative sample of adopters and non‐adopters of these vehicles in Sweden were surveyed. Differences between adopters and non‐adopters on sociodemographic and VBN factors were analyzed and the explanatory ability of the different factors on adoption was analyzed using logistic regression. The results showed that early adopters had a higher level of education and were much more likely to live in multi‐person households compared to non‐adopters. In terms of attitudinal factors, adopters exhibited higher levels of proenvironmental values, beliefs, and personal norms (PNs). Furthermore the results established that VBN factors were successful in explaining the early adoption of a high involvement eco‐innovation such as the AFV. The implications for consumer research, public policymakers, and for marketers of eco‐innovations are discussed. Copyright © 2011 John Wiley & Sons, Ltd.
Identification of CYP106A2 as a Regioselective Allylic Bacterial Diterpene Hydroxylase
Authors: Bleif Sabrina , Hannemann Frank , Lisurek Michael , von Kries Jens Peter , Zapp Josef , Dietzen Matthias , Antes Iris , Bernhardt Rita 
Published: January 2011

AbstractThe cytochrome P450 monooxygenase CYP106A2 from Bacillus megaterium ATCC 13368 catalyzes hydroxylations of a variety of 3‐oxo‐Δ4‐steroids such as progesterone and deoxycorticosterone (DOC), mainly in the 15β‐position. We combined a high‐throughput screening and a rational approach for identifying new substrates of CYP106A2. The diterpene resin acid abietic acid was found to be a substrate and was docked into the active site of a CYP106A2 homology model to provide further inside into the structural basis of the regioselectivity of hydroxylation. The products of the hydroxylation reaction were analyzed by HPLC and the Vmax and Km values were calculated. The corresponding reaction products were analyzed by NMR spectroscopy and identified as 12α‐ and 12β‐hydroxyabietic acid. CYP106A2 was therefore identified as the first reported bacterial cytochrome P450 diterpene hydroxylase. Furthermore, an effective whole‐cell catalyst for the selective allylic 12α‐ and 12β‐hydroxylation was applied to produce the hydroxylated products.
Copper(I)–Anilide Complex [Na(phen)3][Cu(NPh2)2]: An Intermediate in the Copper‐Catalyzed N‐Arylation of N‐Phenylaniline
Authors: Tseng Chia‐Kai , Lee Chi‐Rung , Han Chien‐Chung , Shyu Shin‐Guang 
Published: January 2011

AbstractComplex [Na(phen)3][Cu(NPh2)2] (2), containing a linear bis(N‐phenylanilide)copper(I) anion and a distorted octahedral tris(1,10‐phenanthroline)sodium counter cation, has been isolated from the catalytic CN cross‐coupling reaction with the CuI/phen/tBuONa (phen=1,10‐phenanthroline) catalytic system. Complex 2 can react with 4‐iodotoluene to produce 4‐methyl‐N,N‐diphenylaniline (3 a) with 70.6 % yield. In addition, 2 can work as an effective catalyst for CN coupling under the same reaction conditions, thus indicating that 2 is the intermediate of the catalytic system. Both [Cu(NPh2)2]− and [Cu(NPh2)I]− have been observed by in situ electron ionization mass spectrometry (ESI‐MS) under catalytic reaction conditions, thus confirming that they are intermediates in the reaction. A catalytic cycle has been proposed based on these observations. The molecular structure of 2 has been determined by single‐crystal X‐ray diffraction analysis.
Direct Hydrogenation of Nitroaromatics and One‐Pot Amidation with Carboxylic Acids over Platinum Nanowires
Authors: Li Min , Hu Lei , Cao Xueqin , Hong Haiyan , Lu Jianmei , Gu Hongwei 
Published: January 2011

AbstractA novel ultrathin platinum nanowire with uniform length and a diameter of 1.5 nm was synthesized by acidic etching of FePt nanowire in methanol. This nanowire was characterized by high‐resolution transmission electron microscopy (HRTEM). X‐ray diffraction (XRD) data indicated that the main plane is (111). The ability of this nanowire to catalyze the heterogeneous hydrogenation of nitroaromatics to give the corresponding amines has been investigated. The catalyst showed satisfactory activity in various solvents under mild conditions and showed excellent stability. The catalytic performance was also evaluated in the one‐pot reduction of nitroaromatics and amidation with carboxylic acids under a hydrogen atmosphere at 100 °C. These methods for the hydrogenation of nitroaromatics and the direct amidation of nitroaromatics with carboxylic acids are simple, economical, and environmentally benign, and have practical advantages for the synthesis of amines and amides without the production of toxic byproducts.
Ultrahigh Density Arrays of Toroidal ZnO Nanostructures by One‐Step Cooperative Self‐Assembly Processes: Mechanism of Structural Evolution and Hybridization with Au Nanoparticles
Authors: Jang Yoon Hee , Yang Seung Yun , Jang Yu Jin , Park Cheolmin , Kim Jin Kon , Kim Dong Ha 
Published: January 2011

AbstractA quick protocol for the fabrication of ultrahigh density arrays of toroidal ZnO nanostructures with tailored structures on a substrate surface is presented based on the one‐step spin coating of a common solution composed of inverse micelles of polystyrene‐block‐poly(4‐vinyl pyridine) copolymers (PS‐b‐P4VP) and sol–gel precursors without the need of conventional complex lithographic techniques. ZnO toroids decorated with gold nanoparticles are also obtained by subsequent loading and reduction of metallic precursors. It was elucidated that the diethanolamine moiety in the sol–gel precursors, which induces selective swelling and structural reorganization of the P4VP core blocks, plays a key role in the generation of toroidal nanostructures. Toroidal ZnO nanostructures embedded in a PS‐b‐P4VP matrix films or arrays of pure wurtzite ZnO nanorings are obtained by calcination under inert atmosphere. The structural parameters of the toroidal nanostructures such as the width, height, diameter of the rims as well as the spacing of their 2D arrays are controlled by employing PS‐b‐P4VP with different molecular weight and varying the mixing protocols.
Germline mutations of the E‐cadherin gene in families with inherited invasive lobular breast carcinoma but no diffuse gastric cancer
Authors: Xie Ze Ming , Li Lai Sheng , Laquet Claire , Penault‐Llorca Frédérique , Uhrhammer Nancy , Xie Xiao Ming , Bignon Yves Jean 
Published: January 2011

AbstractBACKGROUND:Present data are highly suggestive but do not unequivocally prove the cosegregation of germ‐line CDH1 mutations with inherited invasive lobular breast cancer (ILBC).METHODS:Two Caucasian families with 6 pathologically confirmed ILBC cases but no diffuse gastric cancer (DGC) were identified in our oncogenetics consultations. Screening for mutations of CDH1, BRCA1, and BRCA2 genes was performed on blood samples. When available, loss of heterozygosity (LOH) and immunohistochemistry (IHC) analyses were performed on tumor samples.RESULTS:No BRCA1 or BRCA2 mutation was found. Deleterious CDH1 germ‐line mutations c.283C>T and c.1582del were found in all the 4 living women with ILBC in family 1 and family 2, respectively. The mutation c.283C>T was also present in a healthy 71‐year‐old male and 2 obligate carriers in family 1. No DGC was observed in the 2 families. Loss of the wild‐type CDH1 allele in 1 of the breast tumors was confirmed by LOH and IHC studies, in accordance with the “2‐hit” model of tumor suppressor genes.CONCLUSIONS:Germline CDH1 mutation can be cosegregated with ILBC in the absence of DGC. Present data do not support recommendation of prophylactic gastrectomy in CDH1 germline mutation carriers with ILBC. Cancer 2011. © 2011 American Cancer Society.
Fluorescence Correlation Spectroscopy of Fast Chain Dynamics within Denatured Protein L
Authors: Sherman Eilon , Haran Gilad 
Published: January 2011

AbstractIntramolecular dynamics in the denatured state of a protein are of importance for protein folding. Native‐like contact formation within the ensemble of denatured conformations of a protein may guide its transformation towards the native conformation. The efficiency of folding is thus dependent on the diffusion of chain fragments, which facilitates contact formation. Herein we investigate intramolecular diffusion of denatured molecules of the small two‐state‐folding protein L with fluorescence correlation spectroscopy (FCS). We utilize the specific quenching of the fluorescence of the oxazine dye Atto655 labeling a cysteine at position 64 (the C‐terminus of the protein) by the side chain of a tryptophan at position 47. FCS measurements allow us to probe processes ranging in timescales from tens of nanoseconds to seconds. Two fast photophysical processes can be distinguished in the fluorescence correlation curves. The slower of the two is found to be due to triplet dynamics, while the faster process is attributed to the quenching of the Atto655 by the tryptophan upon transient ground‐state complex formation. We study the dependence of the intrachain dynamics of the denatured protein on the concentration of the denaturant guanidinium chloride (GdmCl), and extract complex association and dissociation rates. While the dissociation rate does not depend on the denaturant, the association rate decreases as denaturant concentration is increased from 3 to 7 M GdmCl. This decrease in contact formation rate tracks the expansion of denatured protein L, measured in our previous work. Thus, the intramolecular diffusion coefficient calculated from the results is found to be essentially independent of the denaturant concentration over this range, even as the protein expands by more than 20 %.