bluuebunny/crossref_metadata_2025 huggingface dataset:
Three‐dimensional structure of the Fab fragment of a neutralizing antibody to human rhinovirus serotype 2
Authors: Tormo José , Fita Ignasi , Stadler Elisabeth , Skern Tim , Auer Herbert , Blaas Dieter , Kanzler Otto , Betzel Christian
Published: February 2009

The crystal structure of the antigen‐binding fragment of a monoclonal antibody (8F5) that neutralizes human rhinovirus serotype 2 has been determined by X‐ray diffraction studies. Antibody 8F5, obtained by immunization with native HRV2 virions, cross‐reacts with peptides of the viral capsid protein VP2, which contribute to the neutralizing immunogenic site B in this serotype. The structure was solved by the molecular replacement method and has been refined to an R‐factor of 18.9% at 2.8 Å resolution. The elbow angle, relating the variable and constant modules of the molecule is 127°, representing the smallest elbow angle observed so far in an Fab fragment. Furthermore, the charged residues of the epitope can be well accommodated in the antigen‐binding site. This is the first crystal structure reported for an antibody directed against an icosahedral virus.
Expression, purification, and characterization of the functional dimeric cytoplasmic domain of human erythrocyte band 3 in Escherichia coli
Authors: Wang Cheng C. , Moriyama Ryuichi , Low Philip S. , Badylak Janine A. , Dixon Jack E. , Lux Samuel E.
Published: February 2009

The cytoplasmic domain of the human erythrocyte membrane protein, band 3 (cdb3), contains binding sites for hemoglobin, several glycolytic enzymes, band 4.1, band 4.2, and ankyrin, and constitutes the major linkage between the membrane skeleton and the membrane. Although erythrocyte cdb3 has been partially purified from proteolyzed red blood cells, further separation of the water‐soluble 43‐kDa and 41‐kDa proteolytic fragments has never been achieved. In order to obtain pure cdb3 for crystallization and site‐directed mutagenesis studies, we constructed an expression plasmid that has a tandemly linked T7 promoter placed upstream of the N‐terminal 379 amino acids of the erythrocyte band 3 gene. Comparison of several Escherichia coli strains led to the selection of the BL21 (DE3) strain containing the pLysS plasmid as the best host for efficient production of cdb3. About 10 mg of recombinant cdb3 can be easily purified from 4 L of E. coli culture in two simple steps. Comparison of cdb3 released from the red blood cell by proteolysis with recombinant cdb3 reveals that both have the same N‐terminal sequence, secondary structure, and pH‐dependent conformational change. The purified recombinant cdb3 is also a soluble stable dimer with the same Stokes radius as erythrocyte cdb3. The affinities of the two forms of cdb3 for ankyrin are essentially identical; however, recombinant cdb3 with its unblocked N‐terminus exhibits a slightly lower affinity for aldolase.
Synthetic “interface” peptides alter dimeric assembly of the HIV 1 and 2 proteases
Authors: Babé Lilia M. , Rosé Jason , Craik Charles S.
Published: February 2009

Retroviral proteases are obligate homodimers and play an essential role in the viral life cycle. Dissociation of dimers or prevention of their assembly may inactivate these enzymes and prevent viral maturation. A salient structural feature of these enzymes is an extended interface composed of interdigitating N‐ and C‐terminal residues of both monomers, which form a four‐stranded β‐sheet. Peptides mimicking one β‐strand (residues 95–99), or two β‐strands (residues 1–5 plus 95–99 or 95–99 plus 95–99) from the human immunodeficiency virus 1 (HIV1) interface were shown to inhibit the HIV1 and 2 proteases (PRs) with IC50's in the low micromolar range. These interface peptides show cognate enzyme preference and do not inhibit pepsin, renin, or the Rous sarcoma virus PR, indicating a degree of specificity for the HIV PRs. A tethered HIV1 PR dimer was not inhibited to the same extent as the wild‐type enzymes by any of the interface peptides, suggesting that these peptides can only interact effectively with the interface of the two‐subunit HIV PR. Measurements of relative dissociation constants by limit dilution of the enzyme show that the one‐strand peptide causes a shift in the observed Kd for the HIV1 PR. Both one‐ and two‐strand peptides alter the monomer/dimer equilibrium of both HIV1 and HIV2 PRs. This was shown by the reduced cross‐linking of the HIV2 PR by disuccinimidyl suberate in the presence of the interface peptides. Refolding of the HIV1 and HIV2 PRs with the interface peptides shows that only the two‐strand peptides prevent the assembly of active PR dimers. Although both one‐ and two‐strand peptides seem to affect dimer dissociation, only the two‐strand peptides appear to block assembly. The latter may prove to be more effective backbones for the design of inhibitors directed toward retroviral PR dimerization in vivo.
On the multiple simultaneous superposition of molecular structures by rigid body transformations
Authors: Diamond R.
Published: February 2009

A method of optimally superimposing n coordinate sets on each other by rigid body transformations, which minimizes the sum of all n(n ‐ 1)/2 pairwise residuals, is presented. In the solution phase the work load is approximately linear on n, is independent of the size of the structures, is independent of their initial orientations, and terminates in one cycle if n = 2 or if the coordinate sets are exactly superposable, and otherwise takes a number of cycles dependent only on genuine shape differences. Enantiomorphism, if present, is detected, in which case the option exists to reverse or not to reverse the chirality of relevant coordinate sets. The method also offers a rational approach to the problem of multiple minima and has successfully identified four distinct minima in such a case. Source code, which is arranged to enable the study of the disposition of domains in multidomain structures, is available from the author.
Specificity mapping of cellulolytic enzymes: Classification into families of structurally related proteins confirmed by biochemical analysis
Authors: Claeyssens Marc , Henrissat Bernard
Published: February 2009

The specificities of 15 cellulolytic enzymes have been examined using chromophoric glycosides derived from d‐glucose, cellobiose, higher cellooligosaccharides, lactose, d‐xylose, and β‐(1,4)‐xylobiose. Coinciding with a classification based on hydrophobic cluster analysis of amino acid sequences, six families each showing a characteristic specificity pattern were observed. Furthermore, in these cases where the anomeric forms of reaction products were determined, results seem to indicate conservation of intrinsic reaction mechanism (single or double displacement) within each family. On the other hand, the low molecular weight substrates do not discriminate exo‐ from endocellulases. This functional differentiation is speculated to originate from the presence, in exoenzymes, of a tunnel‐shaped active site formed by extra loops in their structure.
The calmodulin‐binding site of the plasma membrane Ca2+ pump interacts with the transduction domain of the enzyme
Authors: Falchetto Rocco , Vorherr Thomas , Carafoli Ernesto
Published: February 2009

Calpain proteolysis of the plasma membrane Ca2+ pump removes a C‐terminal 14‐kDa portion which includes the calmodulin‐binding domain. This produces a fully activated 124‐kDa fragment, which can be inhibited by synthetic versions of the calmodulin‐binding domain. The inhibition is strongest when Trp‐8 in the latter domain is replaced by a Tyr residue (Falchetto, R., Vorherr, T., Brunner, J., & Carafoli, E., 1991, J. Biol. Chem. 266, 2930–2936). In the present study, the N‐terminus of the 28‐residue synthetic calmodulin‐binding domain was acetylated with 3H‐acetic anhydride, and Phe in position 25 was replaced by a phenylalanine derivatized with a diazirine‐based, photoactivatable carbene precursor. This peptide (C28WC*) inhibited the fully active 124‐kDa fragment of the pump and became cross‐linked to it upon photolysis. After proteolysis of the fragment with Asp‐N or Staphylococcus aureus V8 (Glu‐C) protease, labeled peptides were isolated by reversed‐phase high‐performance liquid chromatography and subjected to Edman sequence analysis. The peptides originated from a region of the pump located within the unit protruding into the cytoplasm between transmembrane domain two and three. This unit has been proposed to be the site of the energy transduction domain, which would couple the ATP hydrolysis to Ca2+ translocation.
Isolation and characterization of porcine somatotropin containing a succinimide residue in place of aspartate129
Authors: Violand B.N. , Schlittler M.R. , Kolodziej E.W. , Toren P.C. , Cabonce M.A. , Siegel N.R. , Duffin K.L. , Zobel J.F. , Smith C.E. , Tou J.S.
Published: February 2009

Aspartate129 in porcine somatotropin was converted into a cyclic imide residue (succinimide) under acidic solution conditions. Reversed‐phase high performance liquid chromatography was utilized to isolate and quantitate this altered species, which accounted for approximately 30% of the total protein. The molecular mass of this modified species was determined by electrospray mass spectrometry to be 18 Da less than normal porcine somatotropin, indicative of a loss of 1 H2O molecule. Tryptic peptide mapping demonstrated that the peptide composed of residues 126–133 was altered in this modified protein. Amino acid analysis, amino acid sequencing, mass spectrometry, and capillary zone electrophoresis were used to demonstrate that aspartate129 in this peptide had been converted into a succinimide residue. Further confirmation that this peptide contained a succinimide was obtained by hydrolyzing the modified peptide at pH 9.0, which yielded both the aspartate and isoaspartate peptides.
Constraints imposed by protease accessibility on the trans‐membrane and surface topography of the colicin E1 ion channel
Authors: Zhang Yan‐Liang , Cramer William A.
Published: February 2009

The surface topography of a 190‐residue COOH‐terminal colicin E1 channel peptide (NH2‐Met 333‐Ile 522‐COOH) bound to uniformly sized 0.2‐μm liposomes was probed by accessibility of the peptide to proteases in order (1) to determine whether the channel structure contains trans‐membrane segments in addition to the four α‐helices previously identified and (2) to discriminate between different topographical possibilities for the surface‐bound state. An unfolded surface‐bound state is indicated by increased trypsin susceptibility of the bound peptide relative to that of the peptide in aqueous solution. The peptide is bound tightly to the membrane surface with Kd < 10−7 M. The NH2‐terminal 50 residues of the membrane‐bound peptide are unbound or loosely bound as indicated by their accessibility to proteases, in contrast with the COOH‐terminal 140 residues, which are almost protease inaccessible. The general protease accessibility of the NH2‐terminal segment Ala 336‐Lys 382 excludes any model for the closed channel state that would include trans‐membrane helices on the NH2‐terminal side of Lys 382. Lys 381‐Lys 382 is a major site for protease cleavage of the surface‐bound channel peptide. A site for proteinase K cleavage just upstream of the amphiphilic gating hairpin (K420‐K461) implies the presence of a surface‐exposed segment in this region. These protease accessibility data indicate that it is unlikely that there are any α‐helices on the NH2‐terminal side of the gating hairpin K420‐K461 that are inserted into the membrane in the absence of a membrane potential. A model for the topography of an unfolded monomeric surface‐bound intermediate of the colicin channel domain, including a trans‐membrane hydrophobic helical hairpin and two or three long surface‐bound helices, is proposed.
Comprehensive sequence analysis of the 182 predicted open reading frames of yeast chromosome III
Authors: Bork Peer , Ouzounis Christos , Sander Chris , Scharf Michael , Schneider Reinhard , Sonnhammer Erik
Published: February 2009

With the completion of the first phase of the European yeast genome sequencing project, the complete DNA sequence of chromosome III of Saccharomyces cerevisiae has become available (Oliver, S.G., et al., 1992, Nature 357, 38–46). We have tested the predictive power of computer sequence analysis on the 176 probable protein products of this chromosome, after exclusion of six problem cases. When the results of database similarity searches are pooled with prior knowledge, a likely function can be assigned to 42% of the proteins, and a predicted three‐dimensional structure to a third of these (14% of the total). The function of the remaining 58% remains to be determined. Of these, about one‐third have one or more probable transmembrane segments. Among the most interesting proteins with predicted functions are a new member of the type X polymerase family, a transcription factor with an N‐terminal DNA‐binding domain related to GAL4, a “fork head” DNA‐binding domain previously known only in Drosophila and in mammals, and a putative methyltransferase. Our analysis increased the number of known significant sequence similarities on chromosome III by 13, to now 67. Although the near 40% success rate of identifying unknown protein function by sequence analysis is surprisingly high, the information gap between known protein sequences and unknown function is expected to widen and become a major bottleneck of genome projects in the near future. Based on the experience gained in this test study, we suggest that the development of an automated computer workbench for protein sequence analysis must be an important item in genome projects.
Characterization of the stabilizing effect of point mutations of pyruvate oxidase from lactobacillus plantarum: Protection of the native state by modulating coenzyme binding and subunit interaction
Authors: Risse Bernhard , Stempfer Günter , Rudolph Rainer , Schumacher Günter , Jaenicke Rainer
Published: February 2009

Point mutations in the gene of pyruvate oxidase from Lactobacillus plantarum, with proline residue 178 changed to serine, serine 188 to asparagine, and alanine 458 to valine, as well as a combination of the three single point mutations, lead to a significant functional stabilization of the protein. The enzyme is a tetrameric flavoprotein with tightly bound cofactors, FAD, TPP, and divalent metal ions. Thus, stabilization may be achieved either at the level of tertiary or quaternary interactions, or by enhanced cofactor binding. In order to discriminate between these alternatives, unfolding, dissociation, and cofactor binding of the mutant proteins were analyzed. The point mutations do not affect the secondary and tertiary structure, as determined by circular dichroism and protein fluorescence. Similarly, the amino acid substitutions neither modulate the enzymatic properties of the mutant proteins nor do they stabilize the structural stability of the apoenzymes. This holds true for both the local and the global structure with unfolding transitions around 2.5 M and 5 M urea, respectively. On the other hand, deactivation of the holoenzyme (by urea or temperature) is significantly decreased.

The most important stabilizing effect is caused by the Ala‐Val exchange in the C‐terminal domain of the molecule. Its contribution is close to the value observed for the triple mutant, which exhibits maximum stability, with a shift in the thermal transition of ca. 10 °C. The effects of the point mutations on FAD binding and subunit association are interconnected. Because FAD binding is linked to oligomerization, the stability of the mutant apoenzyme‐FAD complexes is increased. Accordingly, mutants with maximum apparent FAD binding exhibit maximum stability. Analysis of the quaternary structure of the mutant enzymes in the absence and in the presence of coenzymes gives clear evidence that both improved ligand binding and subunit interactions contribute to the observed thermal stabilization.
A structural model for the nucleotide binding domains of the flavocytochrome b–245 β‐chain
Authors: Taylor William R. , Jones David T. , Segal Anthony W.
Published: February 2009

NADPH is a system in phagocytic cells that generates O2− and hydrogen peroxide in the endocytic vacuole, both of which are important for killing of the engulfed microbe. Dysfunction of this oxidase results in the syndrome of chronic granulomatous disease, characterized by a profound predisposition to bacterial and fungal infections. A flavocytochrome b is the site of most of the mutations causing this syndrome. The FAD and NADPH binding sites have been located on the β subunit of this molecule, the C‐terminal half of which showed weak sequence similarity to other reductases, including the ferredoxin‐NADP reductase (FNR) of known structure. This enabled us to build a model of the nucleotide binding domains of the flavocytochrome using this structure as a template. The model was built initially using a novel automatic modeling method based on distance–matrix projection and then refined using energy minimization with appropriate side‐chain torsional constraints. The resulting model rationalized much of the observed sequence conservation and identified a large insertion as a potential regulatory domain. It confirms the inclusion of the neutrophil flavocytochrome b‐245 (Cb‐245) as a member of the FNR family of reductases and strongly supports its function as the proximal electron transporting component of the NADPH oxidase.
Predicting repeat protein folding kinetics from an experimentally determined folding energy landscape
Authors: Street Timothy O. , Barrick Doug
Published: February 2009

The Notch ankyrin domain is a repeat protein whose folding has been characterized through equilibrium and kinetic measurements. In previous work, equilibrium folding free energies of truncated constructs were used to generate an experimentally determined folding energy landscape (Mello and Barrick, Proc Natl Acad Sci USA 2004;101:14102–14107). Here, this folding energy landscape is used to parameterize a kinetic model in which local transition probabilities between partly folded states are based on energy values from the landscape. The landscape‐based model correctly predicts highly diverse experimentally determined folding kinetics of the Notch ankyrin domain and sequence variants. These predictions include monophasic folding and biphasic unfolding, curvature in the unfolding limb of the chevron plot, population of a transient unfolding intermediate, relative folding rates of 19 variants spanning three orders of magnitude, and a change in the folding pathway that results from C‐terminal stabilization. These findings indicate that the folding pathway(s) of the Notch ankyrin domain are thermodynamically selected: the primary determinants of kinetic behavior can be simply deduced from the local stability of individual repeats.
Investigation of the chromium ions recharging kinetics in Cr,Mg:YAG crystal during high‐temperature annealing
Authors: Ubizskii S. , Buryy O. , Börger A. , Becker K.‐D.
Published: February 2009

The optical absorption spectra of Cr,Mg:YAG crystals are studied at in‐situ conditions during high‐temperature annealing in reducing and oxidizing atmospheres. The spectra in the visible and near‐infrared regions are measured at temperatures up to 1200 °C. The kinetics of the recharging of chromium ions are studied in the temperature range between 800 °C and 1200 °C and described by mathematical models. The parameters of these models are determined from experimental kinetic curves. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
UV imaging based on AlGaN arrays
Authors: Duboz Jean‐Yves , Brault Julien , Truffer Jean‐Patrick , Robot Jean‐Alexandre , Robin Kristelle , Reverchon Jean Luc
Published: February 2009

AlGaN Schottky photodiode arrays have been fabricated and hybridized to a commercial Si read out circuit. The array has been characterized in terms of current, spatial and temporal noise, and spectral responsivity. The array sensitivity was compared to the one expected from the performance of individual pixels, leading to the conclusion that the sensitivity of the array is currently limited by the read out circuit. Images are demonstrated with various arrays fabricated with different cut off wavelengths from 360 to 290 nm. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
HEMT‐compatible lateral field‐effect rectifier using CF4 plasma treatment
Authors: Chen Wanjun , Wong King‐Yuen , Chenr Kevin J.
Published: February 2009

A HEMT‐compatible power lateral field effect rectifier (L‐FER) is reported and fabricated using the CF4 plasma treatment on a GaN‐on‐Si wafer. The power rectifier features a Schottky‐gate‐controlled two‐dimensional electron gas (2DEG) channel between the cathode and anode. By tying up the Schottky gate and anode together, the forward turn‐on voltage (VF, ON) of the rectifier is determined by the threshold voltage of the channel instead of the Schottky barrier. The L‐FER with a drift length of 15 μm features a VF, ON of 0.78 V at a current density of 100 A/cm2. This device also exhibits a reverse breakdown voltage (BV) of 460 V at a current level of 1mA/mm and a specific on‐resistance (RON, sp) of 2.3 mΩ·cm2, yielding a figure‐of‐merit (BV2/RON, sp) of 92 MW/cm2. The high temperature characteristics of the L‐FER are also investigated. The measurement results show a robust high temperature operation up to 250 °C. The excellent device performances, together with the lateral device structure and process compatibility with AlGaN/GaN HEMT, provide a low‐cost solution for GaN power integrated circuits. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improvement of crystalline quality of InGaN epilayers on various crystal planes of ZnO substrate by metal‐organic vapor phase epitaxy
Authors: Kawai Yohjiro , Ohsuka Shinya , Iwaya Motoaki , Kamiyama Satoshi , Amano Hiroshi , Akasaki Isamu
Published: February 2009

We demonstrated InxGa1‐xN epitaxial growth with InN mole fractions of x = 0.10 to 0.23 on an m‐plane ZnO substrate by metal‐organic vapor phase epitaxy. The crystalline quality of the epilayers was found to be much higher than that of epilayers grown on a GaN template on an m‐plane SiC substrate. The strain of the epilayers was investigated by X‐ray reciprocal space mapping. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Towards green lasing: ingredients for a green laser diode based on GaInN
Authors: Dräger A. D. , Jönen H. , Bremers H. , Rossow U. , Demolon P. , Schenk H. P. D. , Duboz J. Y. , Corbett B. , Hangleiter A.
Published: February 2009

Laser structures based on GaInN quantum wells were investigated using the variable stripe length technique. Two major problems in designing a green emitting laser diode were identified. The first one is the decrease of the optical confinement for increasing wavelength. To avoid this limitation and to simultaneously maintain good optical confinement we grew samples with lattice‐matched AlInN lower cladding layers.

The second major issue is to push the emission of the structures to longer wavelength by increasing the indium concentration in the quantum well. We demonstrate optical gain up to a wavelength of 480 nm (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation and characterization of QDs all ‐silicon
Authors: Giovannozzi Andrea M. , Rocchia Massimiliano , Troia Adriano , Bertinetti Luca , Amato Giampiero
Published: February 2009

Quantum Dots (QDs) all‐ silicon have been prepared through ultrasound treatments of light‐emitting porous silicon layers (PSL) obtained from electrochemically etching of a p type crystalline silicon (c‐Si). The sonication treatments enabled to separate the PS nanoparticles (porousfraction) from the bulk c‐Si as well as to mechanically reduce their dimensions. The ultrasounds processes have been carried out in two different organic solvents (toluene and tetrahydrofurane, THF) which enabled us to obtaine silicon QD emitting light in the blue‐green part of the visible spectrum (estimated QDs dimension below 4nm). Moreover, by adding the proper chemicals in the solvents, such as alkenes or ω‐carboxy alkenes, we have stabilized the QDs achieving surface modification together with size reduction. Photoluminescence spectra of the QDs and TEM images will be presented in this paper. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
SERS‐active substrates based on silvered porous silicon
Authors: Giorgis Fabrizio , Virga Alessandro , Descrovi Emiliano , Chiodoni Angelica , Rivolo Paola , Venturello Alberto , Geobaldo Francesco
Published: February 2009

Silver nanoparticles are obtained through immersion plating of porous Si in AgNO3 solutions and thermal decomposition of Ag nitrate in oxidized pSi. The efficiency of nanostructures as Surface Enhanced Raman Scattering substrates is checked on a Cyanine dye evidencing detectable concentrations as low as 10–7 M. The substrate efficiency is strictly related to the Ag particle morphology, which could yield to either Localized Surface Plasmons coupled to individual particles or to inter‐particle short‐range interaction. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of a biased conductive mask on porous silicon formation
Authors: Oisten Michael K. , Bergstrom Paul L.
Published: February 2009

Patterned macro porous p ‐type silicon has been produced using a conductive chromium and gold mask while the masking layers were electrically biased under a variety of conditions. The purpose of this work is to study the impact on pore formation near the mask edge by the modulation of the electric field orientation adjacent to the mask edge. The goal is to minimize the amount of lateral pore growth at the mask edge. The masking layers were biased at potentials between the anode and cathode potential during electrochemical anodization in an ethanoic hydrofluoric acid solution. Process conditions were defined to transfer a fraction of the total current from the sample substrate to the cathode, effectively controlling the current density in the mask, and control the electric field orientation near the mask edge. The mask bias impacted the etch rate and the profile of the pore growth at the mask edge. It was observed that if the mask was biased with respect to the anode, the impact on the porous silicon profile at the mask edge was greater than with other biasing configurations. It was observed also that the etch rate of the chromium masking layer was accelerated while biasing with respect to the cathode at a constant current density. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Decoherence of intramolecular vibrational entanglement in polyatomic molecules
Authors: Mishima K. , Yamashita K.
Published: February 2009

The decoherence is one of the most crucial obstacles for quantum computing, entanglement, and quantum information science, as, for example, the quantum computing is usually processed in pure state. Therefore, from the chemical interest, it is very important to investigate one of the most important decoherence mechanisms of molecules, intramolecular vibrational redistribution (IVR), from the viewpoint of quantum computing and entanglement in detail. We have found that the molecules well described by local mode picture is more suitable to maintain coherence than those well described by normal mode picture for quantum computing if the vibrational modes of polyatomic molecules are utilized for qubits. A representative light–heavy–light molecule that can be well described by local mode picture, water molecule (H2O), is adopted for calculation examples and discussion. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Characterization of polyphenol compounds from the roots and stems of Parthenocissus laetevirens by high‐performance liquid chromatography/tandem mass spectrometry
Authors: Chen Juanjuan , He Shan , Mao Hui , Sun Cuirong , Pan Yuanjiang
Published: February 2009

A facile method based on high‐performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC/(–)ESI‐MSn) has been established for the analyses of polyphenol compounds in the root and stems of Parthenocissus laetevirens. Two characteristic fragments [C3O2 (68 Da) and C2H2O (42 Da)] were utilized for the structural identification of polyphenols. Based on the reference standards, the fragment C3O2 was presented when the compound possessed a 2,3‐dihydro‐1H‐indene‐4, 6‐diol moiety. Meanwhile, the C2H2O fragment (42 Da) yielded from the resorcinol ring was confirmed by resveratrol and three synthesized compounds identified as (E)‐5‐styrylbenzene‐1,3‐diol, (E)‐4‐styrylphenol and (E)‐4‐(3,4,5‐trimethoxystyryl)phenol. FTICR‐MSn was performed to further confirm the structures of the fragments. Overall, 15 polyphenol compounds were characterized. Three polyphenol compounds were initially and tentatively characterized from P. laetevirens for the first time, and one was proposed as a novel compound. Furthermore, a pair of stereoisomers was readily distinguished by breakdown curves, and the trans‐, cis‐isomers could be identified by HPLC/DAD‐UV spectra. Copyright © 2009 John Wiley & Sons, Ltd.
Affinity capture using chimeric membrane proteins bound to magnetic beads for rapid ligand screening by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Legros Christian , Guette Catherine , Martin‐Eauclaire Marie‐France , Goyffon Max , Tortajada Jeanine
Published: February 2009

The rapid and specific detection of therapeutically important ligands in complex mixtures, that may bind to membrane proteins, remains challenging for many research laboratories and pharmaceutical industries. Through its use in the development of screening assays, mass spectrometry (MS) is currently experiencing a period of tremendous expansion. In the study presented here, we took advantage of the remarkable stability properties of a bacterial membrane protein, the KcsA K+channel, produced inE.coliand purified as a tetrameric protein in the presence of a detergent. This membrane protein can subserve as a molecular template to display the pore‐forming region of human K+channels, which are considered as targets in the search for inhibitory ligands. The engineered chimeric proteins were linked to metal‐bound magnetic beads, for the screening of complex peptide mixtures, such as that of scorpion venoms. The affinity‐captured scorpion toxins were eluted prior to matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS), and to nano‐electrospray ionization tandem mass QqTOF mass spectrometry (MS/MS) analysis. Thede novosequence of the toxins was deduced by combining the MS/MS fragmentation of the reduced form (up to the 33 first residues) and the trypsin digest peptides of the native toxins. This affinity‐capture screening assay led to the isolation and characterization of potent and specific ligands of the human K+channel, Kv1.3. The affinity‐capture procedure is fast and reproducible. When linked to magnetic beads, the chimeric membrane protein can be re‐used several times without losing any of its selectivity or specificity. This assay also benefits from the fact that it requires minimal amounts of animal venoms or complex mixtures, which can be expensive or difficult to procure. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and Characterisation of Rare Earth Complexes Supported by para‐Substituted Cinnamate Ligands
Authors: Deacon Glen B. , Forsyth Maria , Junk Peter C. , Leary Stuart G. , Lee Winnie W.
Published: February 2009

The preparations and characterisations of a range of lanthanoid 4‐(R)‐substituted (4‐Rcinn, R = OH, OMe, NO2, Cl), known to have good anticorrosion properties, are reported. The crystal structure of [Ce(4‐OHcinn)3(MeOH)2(H2O)]·MeOH is a polymer, in which the cerium atoms are nonacoordinate, and adjacent cerium atoms are bridged by either two bridging bidentate or two bridging tridentate carboxylate ligands. Each cerium atom also has one monodentate 4‐hydroxycinnamate ligand, one aqua ligand, and two methanol ligands.
Plasma Lipid Transfer Enzymes in Non‐Diabetic Lean and Obese Men and Women
Authors: Magkos Faidon , Mohammed B. S. , Mittendorfer Bettina
Published: February 2009

There are considerable differences in the plasma lipid profile between lean and obese individuals and between men and women. Little, however, is known regarding the effects of obesity and sex on the plasma concentration of enzymes involved in intravascular lipid remodeling. Therefore, we measured the immunoreactive protein mass of lipoprotein lipase (LPL), hepatic lipase (HL), cholesterol‐ester transfer protein (CETP) and lecithin‐cholesterol acyl transferase (LCAT) in fasting plasma samples from 40 lean and 40 obese non‐diabetic men and premenopausal women. Women, compared with men, had ~5% lower plasma LCAT (p < 0.041), ~35% greater LPL (p = 0.001) and ~10% greater CETP (p = 0.085) concentrations. Obese, compared with lean individuals of both sexes, had ~30% greater plasma LCAT (p < 0.001), ~20% greater CETP (p < 0.001) and ~20% greater LPL (p = 0.071) concentrations. Plasma HL concentration was not different in lean men and women. Obesity was associated with increased (by ~50%) plasma HL concentration in men (p = 0.018) but not in women; consequently, plasma HL concentration was lower in obese women than obese men (p = 0.009). In addition, there were direct correlations between plasma lipid transfer enzyme concentrations and lipoprotein particle concentrations and sizes. There are considerable differences in basal plasma lipid transfer enzyme concentrations between lean and obese subjects and between men and women, which may be partly responsible for respective differences in the plasma lipid profile.
Do Surgical Personnel Really Need to Double‐Glove?
Authors: Thomas‐Copeland Janet
Published: February 2009

In 2007, AORN's Recommended Practices Task Force revised the “Recommended practices on prevention of transmissible infections in the perioperative practice setting” to recommend that health care practitioners double‐glove during invasive procedures. Previously, AORN had suggested that wearing two pairs of gloves might be indicated for some procedures.

Research on the protective effects of double gloving provides compelling evidence that surgical personnel should double‐glove during all surgical procedures. Statistics on unreported injuries and conversion rates of HIV and hepatitis B indicate that change is difficult; however, research also suggests that objections to double‐gloving can be overcome and a practice change implemented to ensure the safety of health care workers and patients alike. AORN J 89 (February 2009) 322–328. © AORN, Inc, 2009.
NEW CHARACTERIZATIONS OF THE MEROMORPHIC BESOV, Qp AND RELATED CLASSES
Authors: AULASKARI R. , MAKHMUTOV S. , RÄTTYÄ J.
Published: February 2009

Functions in the meromorphic Besov, Qp and related classes are characterized in terms of double integrals of certain oscillation quantities involving chordal distances. Some of the results are analogous to the corresponding results in the analytic case.
A REVISED DUALITY PROOF OF SAMPLING LOCALIZATION IN RELAXATION SPECTRUM RECOVERY
Authors: LOY R. J. , DAVIES A. R. , ANDERSSEN R. S.
Published: February 2009

The duality proof of sampling localization given by Loy, Newbury, Anderssen and Davies in 2001 contains an oversight, as the classes of functions chosen do not assume the compact support. Here, it is shown how a minor change to the argument there yields a precise conclusion.
THE DEGREE OF HOLOMORPHIC APPROXIMATION ON A TOTALLY REAL SET
Authors: ASSERDA SAID
Published: February 2009

LetEbe a totally real set on a Stein open set Ω on a complete noncompact Kähler manifold (M,g) with nonnegative holomorphic bisectional curvature such that (Ω,g) has bounded geometry atE. Then every functionfin aCpclass with compact support on Ω and$\overline \partial $-flat onEup to orderp−1,p≥2 (respectively, in a Gevrey class of orders>1, with compact support on Ω and$\overline \partial $-flat onEup to infinite order) can be approximated on compacts subsets ofEby holomorphic functionsfkon Ω with degree of approximation equalk−p/2(respectively, exp (−c(s)k1/2(s−1)) ).
Cooperation in the liberalization of international trade: after hegemony, what?
Authors: Yarbrough Beth V. , Yarbrough Robert M.
Published: February 2009

Nations dwell in perpetual anarchy, for no central authority imposes limits on the pursuits of sovereign interests. … Because as states, they cannot cede ultimate control over their conduct to an supranational sovereign, they cannot guarantee that they will adhere to their promises. The possibility of a breach of promise can impede cooperation even when cooperation would leave all better off. Yet, at other times, states do realize common goals through cooperation under anarchy.
The use and abuse of Thucydides in international relations
Authors: Bagby Laurie M. Johnson
Published: February 2009

International relations scholars are prone to claiming that the ancient historian of the Peloponnesian War, Thucydides, is a realist of one kind or another. Paul Viotti and Mark Kauppi tell us that Thucydides “is usually credited with being the first writer in the realist tradition as well as the founding father of the international relations discipline.” Michael Doyle writes, “To most scholars in international politics, to think like a Realist is to think as the philosophical historian Thucydides first thought.” Kenneth Waltz found in Thucydides an expression of his “third image,” in which the balance of power states find themselves in largely determines their actions. Robert Keohane and Joseph Nye use Thucydides as a representative of their “overall power model” or the “traditional” international relations paradigm. Both classical realists, who begin with an understanding of human nature, and neorealists, who emphasize the international structure, can find support for their theoretical viewpoint in Thucydides.
Risk and trade regimes: another exploration
Authors: Bates Robert H. , Brock Philip , Tiefenthaler Jill
Published: February 2009

An analysis of a small sample of countries shows that the higher the level of termsof-trade risk that a nation faces in international markets, the more likely it is to increase barriers. The analysis also shows that the greater the availability of social insurance programs mounted by a nation's government, the less likely it is to block free trade. In comparison with the small open economies of Western Europe, therefore, developing countries may remain protectionist because they lack the resources to mount internal programs of transfer payments as a means of coping with risk from international markets.
Negotiating the Single European Act: national interests and conventional statecraft in the European Community
Authors: Moravcsik Andrew
Published: February 2009

The unexpected approval in 1986 of the Single European Act and its program for completing the European Community's internal market by 1992 did not, according to the historical data presented in this article, result from an elite alliance of the European Community Commission, European Parliament, and pan-European business groups. Instead, it rested on interstate bargains involving Britain, France, and Germany, for which the two essential preconditions were the convergence of European economic policy prescriptions following the French turnaround in 1983 and the bargaining leverage that France and Germany gained by threatening to create a “two-track” Europe and exclude Britain. This suggests that theories stressing supranational factors, including certain variants of neofunctionalism, should be supplanted by an “intergovernmental institutionalise” approach combining a realist emphasis on state power and national interests with a proper appreciation of the important role of domestic factors in determining the goals that governments pursue.
Introduction: epistemic communities and international policy coordination
Authors: Haas Peter M.
Published: February 2009

How decision makers define state interests and formulate policies to deal with complex and technical issues can be a function of the manner in which the issues are represented by specialists to whom they turn for advice in the face of uncertainty. The contributors to this issue examine the role that networks of knowledge-based experts—epistemic communities—play in articulating the cause-and-effect relationships of complex problems, helping states identify their interests, framing the issues for collective debate, proposing specific policies, and identifying salient points for negotiation. Their analyses demonstrate that control over knowledge and information is an important dimension of power and that the diffusion of new ideas and data can lead to new patterns of behavior and prove to be an important determinant of international policy coordination.
Regimes, power, and international aviation
Authors: Nayar Baldev Raj
Published: February 2009

Measured against institutionalism and modified structural realism, realism provides the most coherent explanation of the international arrangements pertaining to the issue-area of civil aviation. Although institutionalized international organizations govern technical and safety issues, no single regime has emerged to govern the important commercial matters that bear on states' relative gains and losses. Instead, since World War I states have entered into a multiplicity of denounceable bilateral agreements that in turn reflect the balance of bargaining power between them. States that have attempted to reorganize the system have been driven by their own interests and capabilities, with the stronger aviation powers professing a preference for liberalism.
Democratic states and commitment in international relations
Authors: Gaubatz Kurt Taylor
Published: February 2009

Making credible commitments is a formidable problem for states in the anarchic international system. A long-standing view holds that this is particularly true for democratic states in which changeable public preferences make it difficult for leaders to sustain commitments over time. However, a number of important elements in the values and institutions that have characterized the liberal democratic states should enhance their ability to sustain international commitments. Indeed, an examination of the durability of international military alliances confirms that those between democratic states have endured longer than either alliances between nondemocracies or alliances between democracies and nondemocracies.
The United States in the United Nations
Authors: Alger Chadwick F.
Published: February 2009

Reports on the United Nations by three United States groups, the Commission to Study the Organization of Peace, the President's Commission, and the United Nations Association of the USA, are summarized and compared. They reveal informed concern about United States participation in the UN at a time when Congress and the executive exhibit negativism and neglect. Conclusions are drawn on (1) differing priorities for the UN system and their interdependence, (2) the special capabilities of the United States for setting examples, (3) alternative models for UN problem solving, (4) United States contributions to the UN, and (5) generating political will for creative United States involvement in the UN. Concern is expressed about efforts to cut United States assessments for UN budgets and failure of the reports to adequately consider the political consequences of the fact that “maintenance of international peace and security” is not considered the most important UN task by all members. If congressional and executive neglect are to be overcome, public participation and involvement must be extended.
Sanctions and Security: The League of Nations and the Italian–Ethiopian War, 1935–1936
Authors: Baer George W.
Published: February 2009

The imposition of limited sanctions against Italy was given fair prospect of success by members of the League. Sanctions were to have a twofold purpose. One was to uphold the Covenant and encourage collective security. The other was to end the war by putting pressure on the Italian government so as to make it amenable to a negotiated settlement. It was expected that economic and financial measures (as opposed to military means) would be sufficient, over a period of time, to achieve this. The timetable was upset by unexpected political events and by the collapse of Ethiopian military resistance. Policies are explained, events discussed, and to illuminate some dilemmas a distinction (not then well perceived) is made between politically important “consumatory” assumptions and diplomatically operative “instrumentalist” and reconciliationist practices.
Transnational enterprises and international regulation: A survey of various approaches in international organizations
Authors: Tharp Paul A.
Published: February 2009

Increasing attention is being paid to the development of international codes of behavior and rules of law to regulate the behavior of transnational enterprise. Notable steps in this direction have been taken by the United Nations, the Organization for Economic Cooperation and Development, the European Community, the Andean Common Market and various other organizations. The approaches represented by these efforts can be categorized by the use of four models: the Free Market model; the European Community model; the Multinational Consortium approach; and the Development Community approach. These approaches to the problem of regulation differ in the degree to which they impose prior regulation on multinational firms and in whether they permit the firms to operate as integrated systems or impose arms-length standards on parent-subsidiary relations. Each approach has merits, depending on context and the values of the governments involved.
The appointment of executive heads in UN treaty-based organizations
Authors: Hoole Francis W.
Published: February 2009

The research reported in this article seeks to understand how and why individuals are appointed to serve as executive heads of international organizations. A simple statement of the behavioral rule used in selection of executive heads is developed in the form of an executive head appointment function. The type of data available for the analysis of the appointment of executive heads in international organizations is identified, and an empirical examination of changes in emphasis in the selection of executive heads is reported. The executive head appointment function utilized in the study views appointment as an executive head as a function of six factors (three organizational, one national, and two personal). Discriminant function analysis is used to determine if the function would distinguish between individuals appointed during the period 1945–57 and those appointed from 1958–70 as executive heads in UN treaty-based organizations. It is possible to distinguish, on the basis of the specified executive head appointment function, between executive heads appointed during the two halves of the time period under study. It is therefore reasonable to conclude that the emphasis involved in the selection of executive heads has changed over time in UN treaty-based organizations.
Switzerland and the United Nations
Authors: Gunter Michael M.
Published: February 2009

Despite the approaching universality of the United Nations, Switzerland continues to be a non-member. Her traditional policy of permanent neutrality, which is theoretically incompatible with the United Nations collective security system, and an unsatisfactory experience as a member of the League of Nations largely explain this absence. Ironically enough, however, Switzerland has played in effect as active a role in the United Nations as have many actual members. Switzerland belongs to most of the specialized agencies and many of the Organization's ancillary organs. She has even involved herself in numerous peacekeeping activities. Geneva serves as the Organization's European headquarters. Thus, the Swiss freely participate in what they refer to as the “technical,” as distinguished from the “political” United Nations. The increased prestige of neutrality and neutral Austria's successful membership, approaching universality, the waning of collective security, and a desire to participate fully in international relations are encouraging a gradual reorientation towards the United Nations which may some day lead to formal Swiss membership.