bluuebunny/crossref_metadata_2025 huggingface dataset:
ChemInform Abstract: Facile One‐Pot Synthesis of Thio and Selenourea Derivatives: A New Class of Potent Urease Inhibitors.
Authors: Sivapriya Kirubakaran , Suguna Perumal , Banerjee Arun , Saravanan Vadivelu , Rao Desirazu N. , Chandrasekaran Srinivasan
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Lanthanum Trichloride (LaCl3): An Efficient Catalyst for Conjugate Addition of Amines to Electron‐Deficient Olefins.
Authors: Narsaiah Akkirala Venkat
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Effect of Base Additives on the Selective Hydrogenolysis of Glycerol over Ru/TiO2 Catalyst.
Authors: Feng Jian , Wang Jinbo , Zhou Yafen , Fu Haiyan , Chen Hua , Li Xianjun
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthetic Methodology for the Preparation of N‐Hydroxysulfamides.
Authors: Devanathan Krishnaswamy , Bell Jennifer A. , Wilkins Patricia C. , Jacobs Hollie K. , Gopalan Aravamudan S.
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Efficient One‐Pot Synthesis of Chlorinated Cyclopentenones from Hexachlorocyclopentadiene.
Authors: Ivanova Nadezhda A. , Kislitsina Kseniya S. , Miftakhov Mansur S.
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Rhodium‐Catalyzed Carbonylation of Spiropentanes.
Authors: Matsuda Takanori , Tsuboi Tomoya , Murakami Masahiro
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Electrochemically Induced Aza‐Henry Reaction: A New, Mild, and Clean Synthesis of α‐Nitroamines.
Authors: Rossi Leucio , Bianchi Gabriele , Feroci Marta , Inesi Achille
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Molybdenum Hexacarbonyl and DBU Reduction of Nitro Compounds under Microwave Irradiation.
Authors: Spencer John , Anjum Nazira , Patel Hiren , Rathnam Rajendra P. , Verma Jason
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Highly Efficient Selective Oxidation of Alcohols to Carbonyl Compounds Catalyzed by Ruthenium (III) meso‐Tetraphenylporphyrin Chloride in the Presence of Molecular Oxygen.
Authors: Ji Hong‐Bing , Yuan Qiu‐Lan , Zhou Xian‐Tai , Pei Li‐Xia , Wang Le‐Fu
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: A Facile, One‐Pot Procedure for Forming Diarylimines from Nitroarenes and Benzaldehydes.
Authors: Korich Andrew L. , Hughes Thomas S.
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Studies on Novel Synthetic Methodologies. Part 141. One‐Pot Efficient Synthesis of Cbz‐Protected β‐Amino Ketones: Three‐Component Coupling of Aldehydes, Ketones, and Benzyl Carbamate.
Authors: Das Biswanath , Majhi Anjoy , Chowdhury Nikhil , Reddy Kongara Ravinder , Ravikanth Bommena
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Palladium‐Catalyzed Alkynylcarbonylation of Aryl Iodides with the Use of Mo(CO)6 in the Presence of tBu3P Ligand.
Authors: Iizuka Muneaki , Kondo Yoshinori
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Carbon Dioxide Mediated Catalytic Rearrangement of Propargyl Alcohols into α,β‐Unsaturated Ketones.
Authors: Sugawara Yudai , Yamada Wataru , Yoshida Shunsuke , Ikeno Taketo , Yamada Tohru
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Regioselective Synthesis of Functionally Hindered α‐Methylstyrenes Through Ring Transformation of 2H‐Pyran‐2‐ones with Mesityl Oxide.
Authors: Kumar Amit , Singh Fateh V. , Goel Atul
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: 1‐Methylimidazole‐Catalyzed Regioselective Synthesis of Highly Substituted Benzenes.
Authors: Adib Mehdi , Mohammadi Bagher , Mahdavi Mohammad , Abbasi Alireza , Kesheh Mahdi Riazati
Published: February 2008

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Chiral molecules with polyhedral T, O, or I symmetry: Theoretical solution to a difficult problem in stereochemistry
Authors: Narasimhan Sri Kamesh , Lu Xiaoying , Luk Yan‐Yeung
Published: February 2008

Ever since point groups of symmetry have been used to describe molecules after Van't Hoff and Le Bel proposed tetrahedral structures for carbon atoms in 1874, it remains difficult to design chiral molecules with polyhedral symmetry T, O, or I. Past theoretical and experimental studies have mainly accomplished molecular structures that have the conformations for satisfying the T symmetry. In this work, we present a general theoretical approach to construct rigid molecular structures that have permanently the symmetry of T, O, and I. This approach involves desymmetrizaton of the vertices or the edges of Platonic solid‐shaped molecules with dissymmetric moieties. Using density functional theory (DFT) and assisted model building and energy refinement (AMBER) computational methods, the structure, the rigidity, and the symmetry of the molecule are confirmed by assessing the lowest energy conformation of the molecule, which is initially presented in a planar graph. This method successfully builds molecular structures that have the symmetry of T, O, and I. Interestingly, desymmetrization of the edges has a more stringent requirement of rigidity than desymmetrization of the vertices for affording the T, O, or I symmetry. Chirality, 2008. © 2008 Wiley‐Liss, Inc.
A law of large numbers for finite‐range dependent random matrices
Authors: Anderson Greg , Zeitouni Ofer
Published: February 2008

We consider random Hermitian matrices in which distant above‐diagonal entries are independent but nearby entries may be correlated. We find the limit of the empirical distribution of eigenvalues by combinatorial methods. We also prove that the limit has an algebraic Stieltjes transform by an argument based on dimension theory of Noetherian local rings. © 2008 Wiley Periodicals, Inc.
Soluble HLA‐G molecules impair natural killer/dendritic cell crosstalk via inhibition of dendritic cells
Authors: Gros Frédéric , Cabillic Florian , Toutirais Olivier , Maux Amélie Le , Sebti Yasmine , Amiot Laurence
Published: February 2008

HLA‐G molecules are known to exert immunosuppressive action on DC maturation and on NK cells, and can in consequence inhibit respectively T cell responses and NK cytolysis. In this study, we show that monocyte‐derived DC, differentiated in the presence of GM‐CSF and IL‐4, are sensitive to soluble (s) HLA‐G molecules during LPS/IFN‐γ maturation as demonstrated by the decrease of CD80 and HLA‐DR expressions and IL‐12 secretion. Moreover, DC pretreated with sHLA‐G were found to activate NK/DC crosstalk less than non‐treated DC. Early activation of NK cells co‐cultured with autologous DC was diminished as assessed by CD69 expression. The IFN‐γ production was impaired whereas a slight inhibition of the NK cell cytotoxicity against Daudi cell line was observed. Since sHLA‐G is expressed in grafts or sites of tumour proliferation, its indirect action on NK cells via DC could constitute a pathway of early inhibition for both innate and specific immune responses.
Polypropylene glycol is a selective binding inhibitor for LTA and other structurally related TLR2 agonists
Authors: Draing Christian , Traub Stephanie , Deininger Susanne , Mang Philippa , Möller Heiko M. , Manso Miguel , Rossi Francois , Morath Siegfried , Hartung Thomas , von Aulock Sonja
Published: February 2008

Polypropylene glycol (PPG) is commonly added to bacterial cultures to avoid foaming. However, lipoteichoic acid (LTA) from bacteria grown with PPG lacked cytokine‐inducing potency in human blood. We tested the blocking efficacy of several glycols on the cytokine response to staphylococcal LTA in human blood. PPG 1200 was the most potent inhibitor tested, shown for TNF, IL‐1β, IL‐6, IL‐8, IL‐10 and TGF‐β induction, and displayed no cytotoxic effects. TNF induction by Staphylococcus aureus or by Toll‐like receptor (TLR)2 agonists (di‐ and triacylated lipopeptides and LTA) was also inhibited by PPG 1200, but not that induced by Escherichia coli or TLR4 agonists. In flow cytometric studies, PPG‐carrying nanobeads bound more rhodamine‐labeled LTA than those with glycerol. Additionally, the methyl group peak in the 1H‐NMR of LTA shifted after incubation with increasing PPG 1200 concentrations. Sequential incubation of polystyrene plates with LTA, then PPG 1200 and then blood, with washing steps in between, showed that LTA‐induced TNF release was inhibited. But when PPG 1200 was pre‐incubated with blood that was washed before LTA was added, TNF induction was not repressed, demonstrating that PPG binds LTA and not cellular structures. In summary, PPG 1200 is a novel inhibitor of cytokine induction by TLR2 agonists, which interferes directly with the ligands.
An essential role for transmembrane TNF in the resolution of the inflammatory lesion induced by Leishmania major infection
Authors: Allenbach Cindy , Launois Pascal , Mueller Christoph , Tacchini‐Cottier Fabienne
Published: February 2008

TNF is an essential player in infections with Leishmania major, contributing to the control of the inflammatory lesion and, to a lesser degree, to parasite killing. However, the relative contribution of the soluble and transmembrane forms of TNF in these processes is unknown. To investigate the role of transmembrane TNF (mTNF) in the control of L. major infections, mTNF‐knock‐in (mTNFΔ/Δ) mice, which express functional mTNF but do not release soluble TNF, were infected with L. major, and the development of the inflammatory lesion and the immune response was compared to that occurring in L. major‐infected TNF–/– and wild‐type mice. mTNFΔ/Δ mice controlled the infection and resolved their inflammatory lesion as well as wild‐type mice, a process associated with the early clearance of neutrophils at the site of parasite infection. In contrast, L. major‐infected TNF–/– mice developed non‐healing lesions, characterized by an elevated presence of neutrophils at the site of infection and partial control of parasite number within the lesions. Altogether, the results presented here demonstrate that mTNF, in absence of soluble TNF, is sufficient to control infection due to L. major, enabling the regulation of inflammation, and the optimal killing of Leishmania parasites at the site of infection.
Guest‐Inclusion Behavior of Double‐Strand 1D Coordination Polymers Based on N,N′‐Type Schiff Base Ligands
Authors: Wang Qing , Yang Rui , Zhuang Chun‐Feng , Zhang Jian‐Yong , Kang Bei‐Sheng , Su Cheng‐Yong
Published: February 2008

Four double‐strand one‐dimensional (1D) coordinationpolymers, namely, {[Ni(N3Py)2(NO3)2]·(C6H6)x·C2H5OH}n (1), [Cd(ImBNN)2(CH3C6H4SO3)2]n (2), {[Co(N3OPy)2(H2O)2](ClO4)2·C6H6·H2O}n (3), and {[Co(N3OPy)2(H2O)2](ClO4)2·(C8H10)x}n (4) were obtained from the assembly of three N,N′‐type Schiff base ligands, 1,4‐bis(3‐pyridyl)‐2,3‐diaza‐1,3‐butadiene (N3Py), 2,5‐bis(4′‐(imidazol‐1‐yl)benzyl)‐3,4‐diaza‐2,4‐hexadiene (ImBNN), and bis[4‐(3‐pyridylmethylenemino)phenoxy]methane (N3OPy), with transition‐metal ions. All complexes were characterized by single‐crystal X‐ray diffraction, X‐ray powder diffraction, and FTIR measurements. The guest‐inclusion behavior of these complexes were investigated by thermogravimetric and X‐ray powder diffraction analyses. The structural relationship between the ligands and the cavity sizes and packing fashions have been discussed to elucidate the distinctive guest‐inclusion behavior of these complexes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
The EDTA Complex of Oxidoiron(IV) as Realisation of an Optimal Ligand Environment for High Activity of FeO2+
Authors: Bernasconi Leonardo , Baerends Evert Jan
Published: February 2008

A prerequisite for the high activity of the FeO2+ moiety as a hydroxylation agent is that its ligand environment stabilizes the 3σ*↑LUMO, which dominates the reactivity of this system. Features in the ligand environment that promote the reactivity of FeO2+ are: weak equatorial ligand field to obtain a quintet ground state that stabilizes the unoccupied 3σ*↑; weak axial ligand field to stabilize the 3σ*↑; a positive overall charge to lower the 3σ*↑. Generalised gradient‐corrected Density Functional Theory (DFT) calculations for the series of oxidoiron compounds of composition [FeO·EDTAHn](n–2)+, with n = 0, 1, 2, 3, 4, show that in particular the complex with n = 4 (charge +2) realises such an environment. Hypothetically, these species may appear as intermediates in the degradation of EDTA and related organics in aerated aqueous FeII/EDTA solutions. A strong dependence of the C–H activation properties in the hydroxylation of methane on the overall charge of yielding the lowest C–H dissociation barriers. In the n = 4 case, C–H dissociation occurs with anactivation energy of ca. 7 kJ mol–1, which is below the value computed for the corresponding reaction catalysed by [FeO(H2O)5]2+ (23 kJ mol–1). This enhanced catalytic activity is explained by EDTAHn(2–n)– satisfying the listed requirements for an effective ligand, in particular by the very weak axial coordination by the EDTA nitrogen atoms due to large Fe–N distances.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Investigation on Condensing Agents for Phosphinate Ester Formation with Nucleoside 5′‐Hydroxyl Functions
Authors: Winqvist Anna , Strömberg Roger
Published: February 2008

Condensation of a uridine 3′‐deoxy‐3′‐C‐methylenephosphinate with thymidine and guanosine derivatives to form methylenephosphinate esters was investigated. A number of different condensing agents were compared, and these include pivaloyl chloride, triisopropylbenzenesulfonyl chloride (TPS‐Cl), phosphonium and uronium derivatives, numerous chlorophosphates and bis(2‐oxo‐3‐oxazolidinyl)phosphinic chloride (OXP). The phosphonium derivatives gave slow condensations or oxidative side reactions (hydroxybenzotriazole derivatives) during preactivation of the methylenephosphinate. Pivaloyl chloride gave long coupling times, and competing 5′‐O‐pivaloylation was detected. TPS‐Cl gave rapid condensation but also rapid oxidation of the product. Most chlorophosphates gave competing 5′‐O‐phosphorylation of the nucleoside component, as well as base phosphorylation. However, 2‐chloro‐5,5‐dimethyl‐2‐oxo‐1,3,2‐dioxaphosphorinane (DMOCP) gave a rather efficient formation of dinucleoside methylenephosphinates at a decent rate. However, O6‐protection of guanines could become necessary with this reagent, since upon extended reaction time traces of O6‐phosphorylation were detected even with a low concentration (60 mM) of DMOCP (2 equiv. to phosphinate). Bis(2‐oxo‐3‐oxazolidinyl)phosphinic chloride (OXP) can, unlike DMOCP, be used in nearly equimolar amounts to phosphinate. Under such conditions OXP gives virtually quantitative condensation at a rate comparable to that of 2 equiv. of DMOCP and with no side reactions detected. We could also not detect any decomposition of OXP‐preactivated phosphinate. Nucleophilic catalysts, more powerful than pyridine (N‐methylimidazole, iodide and 4‐methoxypyridine), accelerated the reactions with OXP, but preactivation in the absence of the 5′‐OH component led to decomposition of the activated phosphinate.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Combined Metalation–Cross Coupling Strategies: A Synthesis of Schumanniophytine by a Key Biaryl O‐Carbamate Remote Anionic Fries Rearrangement
Authors: Macklin Todd K. , Reed Mark A. , Snieckus Victor
Published: February 2008

A short synthesis of the alkaloid schumanniophytine (1) starting from simple building blocks and involving directed ortho metalation (DoM), Suzuki–Miyaura cross coupling, and a key ortho‐silicon‐induced O‐carbamate remote anionic Fries rearrangement (3) is described. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Strengthening and rehabilitation of RC beam–column joints using carbon‐FRP jacketing and epoxy resin injection
Authors: Karayannis Chris G. , Sirkelis George M.
Published: February 2008

The scope of this study is to present results of an experimental investigation on the behaviour of critical external beam–column joints repaired or/and strengthened with a combination of epoxy resin injections and carbon‐fibre‐reinforced plastics (C‐FRP) sheets and to extract useful and practical conclusions. The experimental program comprises 12 external beam–column joint connection subassemblages tested in cyclic loading. From the observed responses of the examined specimens it can be deduced that the technique of epoxy resin injections is appropriate for the total rehabilitation of the joints seismic capacity, since no damages have been observed at the joint area of the specimens after the repair. The combination of this technique with the use of C‐FRP sheets leads to a significant improvement of the loading capacity, the energy absorption and the ductility and finally it leads to improved type of damages compared with the damage modes of the specimens during the initial loading. Shortcomings of the application of C‐FRP sheets for practical use are also pointed out. Copyright © 2008 John Wiley & Sons, Ltd.
The creative brain: Investigation of brain activity during creative problem solving by means of EEG and FMRI
Authors: Fink Andreas , Grabner Roland H. , Benedek Mathias , Reishofer Gernot , Hauswirth Verena , Fally Maria , Neuper Christa , Ebner Franz , Neubauer Aljoscha C.
Published: February 2008

Cortical activity in the EEG alpha band has proven to be particularly sensitive to creativity‐related demands, but its functional meaning in the context of creative cognition has not been clarified yet. Specifically, increases in alpha activity (i.e., alpha synchronisation) in response to creative thinking can be interpreted in different ways: As a functional correlate of cortical idling, as a sign of internal top‐down activity or, more specifically, as selective inhibition of brain regions. We measured brain activity during creative thinking in two studies employing different neurophysiological measurement methods (EEG and fMRI). In both studies, participants worked on four verbal tasks differentially drawing on creative idea generation. The EEG study revealed that the generation of original ideas was associated with alpha synchronisation in frontal brain regions and with a diffuse and widespread pattern of alpha synchronisation over parietal cortical regions. The fMRI study revealed that task performance was associated with strong activation in frontal regions of the left hemisphere. In addition, we found task‐specific effects in parietotemporal brain areas. The findings suggest that EEG alpha band synchronisation during creative thinking can be interpreted as a sign of active cognitive processes rather than cortical idling. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.
Brain responses to auditory and visual stimulus offset: Shared representations of temporal edges
Authors: Herdener Marcus , Lehmann Christoph , Esposito Fabrizio , di Salle Francesco , Federspiel Andrea , Bach Dominik R. , Scheffler Klaus , Seifritz Erich
Published: February 2008

Edges are crucial for the formation of coherent objects from sequential sensory inputs within a single modality. Moreover, temporally coincident boundaries of perceptual objects across different sensory modalities facilitate crossmodal integration. Here, we used functional magnetic resonance imaging in order to examine the neural basis of temporal edge detection across modalities. Onsets of sensory inputs are not only related to the detection of an edge but also to the processing of novel sensory inputs. Thus, we used transitions from input to rest (offsets) as convenient stimuli for studying the neural underpinnings of visual and acoustic edge detection per se. We found, besides modality‐specific patterns, shared visual and auditory offset‐related activity in the superior temporal sulcus and insula of the right hemisphere. Our data suggest that right hemispheric regions known to be involved in multisensory processing are crucial for detection of edges in the temporal domain across both visual and auditory modalities. This operation is likely to facilitate cross‐modal object feature binding based on temporal coincidence. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.
Segmentally arranged somatotopy within the face representation of human primary somatosensory cortex
Authors: Moulton Eric A. , Pendse Gautam , Morris Susie , Aiello‐Lammens Matthew , Becerra Lino , Borsook David
Published: February 2008

Though somatotypic representation within the face in human primary somatosensory cortex (S1) to innocuous stimuli is controversial; previous work suggests that painful heat is represented based on an “onion‐skin” or segmental pattern on the face. The aim of this study was to determine if face somatotopy for brush stimuli in S1 also follows this segmental representation model. Twelve healthy subjects (nine men: three women) underwent functional magnetic resonance imaging to measure blood oxygen level dependent signals during brush (1 Hz, 15 s) applied to their faces. Separate functional scans were collected for brush stimuli repetitively applied to each of five separate stimulation sites on the right side of the face. These sites were arranged in a vertical, horizontal, and circular manner encompassing the three divisions of the trigeminal nerve. To minimize inter‐individual morphological differences in the post‐central gyrus across subjects, cortical surface‐based registration was implemented before group statistical image analysis. Based on activation foci, somatotopic activation in the post‐central gyrus was detected for brush, consistent with the segmental face representation model. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.
Photocatalytic degradation of 2,2‐bis(4‐hydroxy‐3‐methylphenyl) propane (BPP) based on molecular recognition interaction
Authors: Wang Guanghui , Huang Lei , Yu Rong , Deng Nansheng
Published: February 2008

BACKGROUND: Endocrine disruptors in the aquatic environment and their potential adverse effects are currently issues of concern. One of these endocrine disruptors is 2,2‐bis(4‐hydroxy‐3‐methylphenyl)propane (BPP). In this work the molecular recognition interaction of BPP with β‐cyclodextrin (β‐CD) was studied using IR spectroscopy and steady state fluorescence spectroscopy, and the photocatalytic degradation behaviour of BPP based on molecular recognition interaction was investigated in a TiO2/UV–visible (λmax = 365 nm) system. This might provide a new method for the treatment of some organic pollutants in wastewater.

RESULTS: β‐CD reacts with BPP to form a 1:1 inclusion complex, the formation constant of which is 4.94 × 103 L mol−1. The photodegradation rate constant of BPP after molecular recognition by β‐CD showed a 1.42‐fold increase in the TiO2/UV–visible (λmax = 365 nm) system. The photodegradation of BPP depended on the concentration of β‐CD, the pH value, the gaseous medium and the initial concentration of BPP. The photodegradation efficiency of BPP with molecular recognition was higher than that without molecular recognition. After 100 min of irradiation the mineralisation efficiency of BPP after molecular recognition by β‐CD reached 94.8%, whereas the mineralisation efficiency of BPP before molecular recognition by β‐CD was only 40.6%.

CONCLUSION: The photocatalytic degradation of BPP after molecular recognition by β‐CD can be enhanced in the TiO2/UV‐visible (λmax = 365 nm) system. This enhancement is dependent on the enhancement of the adsorption of BPP, the moderate inclusion depth of BPP in the β‐CD cavity and the increase in the frontier electron density of BPP after molecular recognition. Copyright © 2008 Society of Chemical Industry
Production of thermostable alkaline lipase on vegetable oils from a thermophilic Bacillus sp. DH4, characterization and its potential applications as detergent additive
Authors: Bora Limpon , Kalita Mohan C
Published: February 2008

BACKGROUND: The alkaline lipase production on vegetable oils as sole carbon source, its characterization and effect of different commercial detergents and surfactants on enzymatic activity from thermophilic Bacillus sp. DH4 was investigated.

RESULTS: The organism grew on mannose, but the amount of lipase secreted was significantly less than on vegetable oils. This study identified a simple substrate for lipase production and established the utility of groundnut oil for increasing the lipase yield. The enzyme was compatible with various ionic and non‐ionic surfactants as well as commercial detergents. Lipase activity was strongly inhibited by sodium dodecyl sulfate (SDS), but not by Triton X‐100 or Triton X‐114. The best assay conditions observed for this lipase was found to be pH 9.0 and 50 °C. The enzyme was stable at alkaline pH and considerable activity was observed at pH 10 and it retained 93% of the residual activity at 60 °C. The lipase showed a novel property of marked activation at alkaline pH. Wash performance analysis of commercial detergent for removal of fatty stains improved upon addition of lipase.

CONCLUSION: The production on cheap vegetable oils, novel properties and resistance towards various surfactants and tolerance to commercial detergents make this lipase a potential additive for detergent formulations. Significance and impact of the study: Bacillus sp. produces alkaline and thermostable lipase on cheap vegetable oils and its compatibility can find use in the detergent industry. Copyright © 2008 Society of Chemical Industry
The macrophage–biomaterial interface: a proteomic analysis of the conditioned medium environment
Authors: Dinnes Donna Lee M , Marçal Helder , Raftery Mark J , Labow Rosalind S , Mahler Stephen M
Published: February 2008

BACKGROUND: Proteomic techniques provide an approach for exploration of intracellular structure and function as well as extracellular microenvironments. However, proteomics has not been extensively applied to examine cell–material interface dynamics or the conditioned medium (CM) that ensues. Monocyte‐derived macrophages (MDM) are of particular interest as they are the predominant cell type contributing to chronic inflammation at long‐term implant sites. The current study compares the CM generated when MDM were adherent to tissue culture polystyrene (TCPS) or a model polycarbonate–urethane (PCNU). Two‐dimensional electrophoresis and either matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry or liquid chromatography Fourier transform mass spectrometry were used for protein identification to begin to assess how the CM is altered when MDM are in contact with a degradable PCNU material relative to a typical tissue culture surface.

RESULTS: Proteomic analysis of CM samples identified regulatory molecules associated with specific activation pathways, such as interferon‐γ, and degradative proteins, such as matrix metalloproteinases and chitinase‐like proteins, suggesting their involvement in the MDM response to PCNU materials. Furthermore, this study illustrates the challenges in analysing CM protein profiles against a background of intracellular protein, originating from lysed cells or cell fragments, and cell culture additives such as fetal bovine serum.

CONCLUSIONS: The microenvironment surrounding an MDM–biomaterial interface is complex, containing proteins that relate to intracellular signalling pathways, cytoskeletal remodelling, degradation as well as the presence of serum factors necessary for cell attachment. The use of proteomics to determine the CM protein profile should continue to aid in the elucidation of cell–material interactions. Copyright © 2008 Society of Chemical Industry
Clarification of a wheat straw‐derived medium with ion‐exchange resins for xylitol crystallization
Authors: Canilha Larissa , Carvalho Walter , Giulietti Marco , Felipe Maria Das Graças Almeida , Almeida E Silva João Batista
Published: February 2008

BACKGROUND: Xylitol bioproduction from lignocellulosic residues comprises hydrolysis of the hemicellulose, detoxification of the hydrolysate, bioconversion of the xylose, and recovery of xylitol from the fermented hydrolysate. There are relatively few reports on xylitol recovery from fermented media. In the present study, ion‐exchange resins were used to clarify a fermented wheat straw hemicellulosic hydrolysate, which was then vacuum‐concentrated and submitted to cooling in the presence of ethanol for xylitol crystallization.

RESULTS: Sequential adsorption into two anion‐exchange resins (A‐860S and A‐500PS) promoted considerable reductions in the content of soluble by‐products (up to 97.5%) and in medium coloration (99.5%). Vacuum concentration led to a dark‐colored viscous solution that inhibited xylitol crystallization. This inhibition could be overcome by mixing the concentrated medium with a commercial xylitol solution. Such a strategy led to xylitol crystals with up to 95.9% purity. The crystallization yield (43.5%) was close to that observed when using commercial xylitol solution (51.4%).

CONCLUSION: The experimental data demonstrate the feasibility of using ion‐exchange resins followed by cooling in the presence of ethanol as a strategy to promote the fast recovery and purification of xylitol from hemicellulose‐derived fermentation media. Copyright © 2008 Society of Chemical Industry
Advanced oxidation processes for water treatment: advances and trends for R&D
Authors: Comninellis Christos , Kapalka Agnieszka , Malato Sixto , Parsons Simon A , Poulios Ioannis , Mantzavinos Dionissios
Published: February 2008

Advanced oxidation comprises a range of similar but different chemical processes aimed at tackling pollution in water, air and soil. Over the past few decades, multidisciplinary research has been carried out to study a broad spectrum of topics such as understanding of process fundamentals, elucidation of kinetics and mechanisms, development of new materials, modelling, process integration and scale‐up. This article identifies and discusses certain directions that seem to advance R&D on advanced oxidation for water/wastewater treatment. Copyright © 2008 Society of Chemical Industry
Production of organic solvent tolerant lipase by Staphylococcus caseolyticus EX17 using raw glycerol as substrate
Authors: Volpato Giandra , Rodrigues Rafael Costa , Heck Júlio Xandro , Ayub Marco Antônio Záchia
Published: February 2008

BACKGROUND: In this work we used Plackett–Burman statistical design and central composite design in order to optimize culture conditions for lipase production by Staphylococcus caseolyticus strain EX17 growing on raw glycerol, which was obtained as a by‐product of the enzymatic synthesis of biodiesel. The stability of lipase was verified over several organic solvents, such as methanol, ethanol and n‐hexane.

RESULTS: Optimal culture conditions for lipase production were found to be 36 °C, initial pH 8.12, glycerol 30 g L−1, olive oil 3.0 g L−1, and soybean oil 2.5 g L−1, with 145.8 U L−1 of enzyme activity. When commercial glycerol was substituted by the raw glycerol from biodiesel synthesis, lipolytic activity was 127.3 U L−1. Experimental validation of enzyme production matched values predicted by the mathematical model, which was 138.3 U L−1. Stability tests showed that lipase from S. caseolyticus EX17 was stable in methanol, ethanol, and n‐hexane.

CONCLUSIONS: Results obtained in this work suggest that raw glycerol can be used for lipase production by S. caseolyticus EX17 and that this enzyme has a potential application in the synthesis of biodiesel. Copyright © 2008 Society of Chemical Industry
Efficient syntheses of benzyl and n‐octyl [1,3‐13C2]acetoacetates, and their application to syntheses of 13C‐labelled pyrrole and 13C‐labelled hymecromone
Authors: Iida Katsumi , Ohtaka Kuniaki , Komatsu Takayuki , Makino Tomoe , Kajiwara Masahiro
Published: February 2008

Benzyl [1‐13C]acetate (2a) was prepared via esterification of sodium [1‐13C]acetate (1) with benzyl bromide in the presence of 18‐crown‐6‐ether in 97% yield. n‐Octyl [1‐13C]acetate (2b) was rapidly obtained by microwave irradiation of 1‐bromooctane and potassium [1‐13C]acetate (obtained by salt exchange of 1) absorbed on Al2O3 in 82% yield. Solvent‐free Claisen condensation of benzyl or n‐octyl [1‐13C]acetate (2a or 2b) in the presence of potassium tert‐butoxide efficiently gave benzyl or n‐octyl [1,3‐13C2]acetoacetate (3a or 3b) in 51 or 68% yield, respectively. Dibenzyl 2,4‐dimethyl[2,4‐13C2]pyrrole‐3,5‐di[13C]carboxylate (4) was synthesized from benzyl [1,3‐13C2]acetoacetate (3a) in 54% yield. [2,4‐13C2]Hymecromone (6) (7‐hydroxy‐4‐methyl[2,4‐13C2]coumarin) was obtained from n‐octyl [1,3‐13C2]acetoacetate (3b) and 1,3‐benzenediol (5) in 73% yield. Copyright © 2008 John Wiley & Sons, Ltd.
Stereoselective synthesis of L‐[15N] amino acids with glucose dehydrogenase and galactose mutarotase as NADH regenerating system
Authors: Chiriac Maria , Lupan Iulia , Bucurenci N. , Popescu O. , Palibroda N.
Published: February 2008

We have developed an efficient stereospecific enzymatic synthesis of L‐[15N]‐valine, L‐[15N]‐leucine, L‐[15N]‐norvaline, L‐[15N]‐norleucine and L‐[15N]‐isoleucine from the corresponding α‐keto acids by coupling the reactions catalysed by leucine dehydrogenase and glucose dehydrogenase/galactose mutarotase. Giving high yields of L‐amino acids, the procedure is economical and easy to perform and to monitor at a synthetically useful scale (1–10 g). Copyright © 2008 John Wiley & Sons, Ltd.
Gallium metal affinity capture tandem mass spectrometry for the selective detection of phosphopeptides in complex mixtures
Authors: Blacken Grady R. , Sadílek Martin , Tureček František
Published: February 2008

Metal affinity capture tandem mass spectrometry (MAC‐MSMS) is evaluated in a comparative study of a lysine‐derived nitrilotriacetic acid (Nα, Nα‐bis‐(carboxymethyl)lysine, LysNTA) and an aspartic‐acid‐related iminodiacetic acid (N‐(4‐aminobutyl)aspartic acid, AspIDA) as selective phosphopeptide detection reagents. Both LysNTA and AspIDA spontaneously form ternary complexes with GaIII and phosphorylated amino acids and phosphopeptides upon mixing in solution. Collision‐induced dissociation of positive complex ions produced by electrospray produces common fragments (LysNTA + H)+ or (AspIDA + H)+ at m/z 263 and 205, respectively. MSMS precursor scans using these fragments as reporter ions allow one to selectively detect multiple charge states of phosphopeptides in mixtures. It follows from this comparative study that LysNTA is superior to AspIDA in detecting phosphopeptides, possibly because of the higher coordination number and greater stability constant for GaIII—phosphopeptide complexation of the former reagent. In a continuing development of MAC‐MSMS for proteomics applications, we demonstrate its utility in a post‐column reaction format. Using a simple post‐column‐reaction ‘T’ and syringe pump to deliver our chelating reagents, α‐casein tryptic phosphopeptides can be selectively analyzed from a solution containing a twofold molar excess of bovine serum albumin. The MAC‐MSMS method is shown to be superior to the commonly used neutral loss scan for the common loss of phosphoric acid. Copyright © 2008 John Wiley & Sons, Ltd.
Hydration, charge, size, and shape characteristics of peptides from their CZE analyses
Authors: Peirotti Marta B. , Piaggio Maria V. , Deiber Julio A.
Published: February 2008

A CZE model is presented for peptide characterization on the basis of well‐established physicochemical equations. The effective mobility is used as basic data in the model to estimate relevant peptide properties such as, for instance, hydration, net and total electrical charge numbers, hydrodynamic size and shape, particle average orientation, and pH‐microenvironment from the charge regulation phenomenon. Therefore 102 experimental effective mobilities of different peptides are studied and discussed in relation to previous work. An equation for the estimation of peptide hydration as a function of ionizing, polar, and non‐polar amino acid residues is included in the model. It is also shown that the shape‐orientation factor of peptides may be either lower or higher than one, and its value depends on a complex interplay among total charge number, molar mass, hydration, and amino acid sequence.
Conus ventricosus venom peptides profiling by HPLC‐MS: A new insight in the intraspecific variation
Authors: Romeo Cristina , Di Francesco Laura , Oliverio Marco , Palazzo Paola , Massilia Gabriella Raybaudi , Ascenzi Paolo , Polticelli Fabio , Schininà Maria Eugenia
Published: February 2008

Conus is a genus of predatory marine gastropods that poison the prey with a complex mixture of compounds active on muscle and nerve cells. An individual cone snail's venom contains a mixture of pharmacological agents, mostly short, structurally constrained peptides. This study is focused on the composition of the venom employed by Conus ventricosus Gmelin, 1791, a worm‐hunting cone snail living in the Mediterranean Sea. For this purpose, LC coupled to MS techniques has been successfully used to establish qualitative and quantitative differences in conopeptides from minute amounts of venom ducts. We were able to prove variability in the venom conopeptide complement, possibly related to different trophic habits of the species in the Mediterranean Sea. Moreover, the information‐rich MS techniques enabled us to identify two novel C. ventricosus peptides, here named Conotoxin‐Vn and α‐Conotoxin‐Vn. On the basis of the structural data collected so far, we suggest that Conotoxin‐Vn is a conopeptide belonging to the ω‐family that recognizes calcium channels through a specific pharmacophore. Similarly, molecular modeling data suggest that α‐Conotoxin‐Vn should represent a competitive antagonist of neuronal nicotinic acetylcholine receptors (nAChRs).
Peptide profile of human acquired enamel pellicle using MALDI tandem MS
Authors: Vitorino Rui , Calheiros‐Lobo Maria João , Duarte José A. , Domingues Pedro M. , Amado Francisco M.L.
Published: February 2008

The present study proposes a strategy for human in vivo acquired enamel pellicle (AEP) peptidome characterisation based on sequential extraction with guanidine and TFA followed by MALDI‐TOF/TOF identification. Three different nanoscale analytical approaches were used: samples were subjected to tryptic digestion followed by nano‐HPLC and mass spectrometry (MS and MS/MS) analysis. Undigested samples were analysed by LC‐MS (both linear and reflector modes) and LC‐MS/MS analysis, and samples were subjected to nano‐HPLC followed by on‐plate digestion and mass spectrometry (MS and MS/MS) analysis. The majority of the identifications corresponded to peptide/protein fragments of salivary protein, belonging to the classes: acidic PRPs, basic PRPs, statherin, cystatins S and SN and histatin 1 (all also identified in intact form). Overall, more than 90 peptides/proteins were identified. Results clearly show that peptides with acidic groups are enriched in the TFA fraction while peptides with no acidic or phosphate groups are prevalent on the guanidine extract. Also, phosphorylated peptides were observed mainly on the TFA fraction. Fragments present in the AEP show a predominance of cleavage points located at Arg, Tyr and Lys residues. Obtained data suggest that proteolytic activity could influence AEP formation and composition.
CASPT2 investigation of ethane dissociation and methyl recombination using canonical variational transition state theory
Authors: Li Hua , Chen Bo‐Zhen , Huang Ming‐Bao
Published: February 2008

Ethane dissociation and the reverse recombination reactions were investigated based on CASPT2 and CASSCF calculations. The CASPT2 (partial) geometry optimization calculations and the CASSCF frequency calculations provided geometrical parameters, potential energies, and vibrational frequencies along the reaction pathway. For determining dissociation and recombination rate constants at a temperature range from 200 to 2000 K, two models (models 1 and 2) were used on the basis of the canonical variational transition state theory. The different methods for accounting for the five transitional modes were proposed in the two models. Dissociation activation parameters evaluated using the two models are in good agreement with the data available in the literature. Model 1 predicts reasonable rate constant values for methyl recombination at high temperature, and model 2 predicts reasonable values in both high‐ and low‐temperature ranges. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 161–173, 2008
Hydroxyl radical reactions with halogenated ethanols in aqueous solution: Kinetics and thermochemistry
Authors: Morozov I. , Gligorovski S. , Barzaghi P. , Hoffmann D. , Lazarou Y. G. , Vasiliev E. , Herrmann H.
Published: February 2008

Laser flash photolysis combined with competition kinetics with SCN− as the reference substance has been used to determine the rate constants of OH radicals with three fluorinated and three chlorinated ethanols in water as a function of temperature. The following Arrhenius expressions have been obtained for the reactions of OH radicals with (1) 2‐fluoroethanol, k1(T) = (5.7 ± 0.8) × 1011 exp((−2047 ± 1202)/T) M−1 s−1, (2) 2,2‐difluoroethanol, k2(T) = (4.5 ± 0.5) × 109 exp((−855 ± 796)/T) M−1 s−1, (3) 2,2,2‐trifluoroethanol, k3(T) = (2.0 ± 0.1) × 1011 exp((−2400 ± 790)/T) M−1 s−1, (4) 2‐chloroethanol, k4(T) = (3.0 ± 0.2) × 1010 exp((−1067 ± 440)/T) M−1 s−1, (5) 2, 2‐dichloroethanol, k5(T) = (2.1 ± 0.2) × 1010 exp((−1179 ± 517)/T) M−1 s−1, and (6) 2,2,2‐trichloroethanol, k6(T) = (1.6 ± 0.1) × 1010 exp((−1237 ± 550)/T) M−1 s−1. All experiments were carried out at temperatures between 288 and 328 K and at pH = 5.5–6.5. This set of compounds has been chosen for a detailed study because of their possible environmental impact as alternatives to chlorofluorocarbon and hydrogen‐containing chlorofluorocarbon compounds in the case of the fluorinated alcohols and due to the demonstrated toxicity when chlorinated alcohols are considered. The observed rate constants and derived activation energies of the reactions are correlated with the corresponding bond dissociation energy (BDE) and ionization potential (IP), where the BDEs and IPs of the chlorinated ethanols have been calculated using quantum mechanical calculations. The errors stated in this study are statistical errors for a confidence interval of 95%. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 174–188, 2008
Detailed chemical kinetic modeling of pyrolysis of ethylene, acetylene, and propylene at 1073–1373 K with a plug‐flow reactor model
Authors: Norinaga Koyo , Janardhanan Vinod M. , Deutschmann Olaf
Published: February 2008

This study examines the predictive capability of our recently proposed reaction mechanism (Norinaga and Deutschmann, Ind Eng Chem Res 2007, 46, 3547) for hydrocarbon pyrolysis at varying temperature. The conventional flow reactor experiments were conducted at 8 kPa, over the temperature range 1073–1373 K, using ethylene, acetylene, and propylene as reactants to validate the mechanism. More than 40 compounds were identified and quantitatively analyzed by on‐ and off‐line gas chromatography. The chemical reaction schemes consisting of 227 species and 827 reactions were coupled with a plug‐flow reactor model that incorporated the experimentally measured axial temperature profile of the reactor. Comparisons between the computations and the experiments are presented for more than 30 products including hydrogen and hydrocarbons ranging from methane to coronene as a function of temperature. The model can predict the compositions of major products (mole fractions larger than 10−2) in the pyrolysis of three hydrocarbons with satisfactory accuracies over the whole temperature range considered. Mole fraction profiles of minor compounds including polycyclic aromatic hydrocarbons (PAHs) up to three ring systems, such as phenanthrene, anthracene, and phenylnaphthalene, are also fairly modeled. At temperatures lower than 1273 K, larger PAHs were underpredicted and the deviation became larger with decreasing temperature and increasing molecular mass of PAHs, while better agreements were found at temperatures higher than 1323 K. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 199–208, 2008