bluuebunny/crossref_metadata_2025_split huggingface dataset:
RIP death domain structural interactions implicated in TNF‐mediated proliferation and survival
Authors: Thakar Juilee , Schleinkofer Karin , Borner Christoph , Dandekar Thomas 
Published: February 2006

AbstractDeath domain (DD)–containing proteins are involved in both apoptosis and survival/proliferation signaling induced by activated death receptors. Here, a phylogenetic and structural analysis was performed to highlight differences in DD domains and their key regulatory interaction sites. The phylogenetic analysis shows that receptor DDs are more conserved than DDs in adaptors. Adaptor DDs can be subdivided into those that activate or inhibit apoptosis. Modeling of six homotypic DD interactions involved in the TNF signaling pathway implicates that the DD of RIP (Receptor interacting protein kinase 1) is capable of interacting with the DD of TRADD (TNFR1‐associated death domain protein) in two different, exclusive ways: one that subsequently recruits CRADD (apoptosis/inflammation) and another that recruits NFκB (survival/proliferation). Proteins 2006. © 2006 Wiley‐Liss, Inc.
Involvement of disulfide bonds and histidine 172 in a unique β‐sheet to α‐helix transition of α1‐acid glycoprotein at the biomembrane interface
Authors: Nishi Koji , Komine Yoshio , Fukunaga Naoko , Maruyama Toru , Suenaga Ayaka , Otagiri Masaki 
Published: February 2006

AbstractHuman α1‐acid glycoprotein (AGP), which is comprised of 183 amino acid residues and 5 carbohydrate chains, is a major plasma protein that binds to basic and neutral drugs as well as to steroid hormones. It has a β‐sheet–rich structure in aqueous solution. Our previous findings suggest that AGP forms an α‐helix structure through an interaction with biomembranes. We report herein on a study of the mechanism of α‐helix formation in AGP using various modified AGPs. The disulfide reduced AGP (R‐AGP) was extensively unfolded, whereas asialylated AGP (A‐AGP) maintained the native structure. Intriguingly, reduced and asialylated AGP (RA‐AGP) increased the α‐helix content as observed in the presence of biomembrane models, and showed a significant decrease in ligand binding capacity. This suggests that AGP has an innate tendency to form an α‐helix structure, and disulfide bonds are a key factor in the conformational transition between the β‐sheet and α‐helix structures. However, RA‐AGP with all histidine residues chemically modified (HRA‐AGP) was found to lose the intrinsic ability to form an α‐helix structure. Furthermore, disulfide reduction of the H172A mutant expressed in Pichia pastoris also caused a similar loss of folding ability. The present results indicate that disulfide bonds and the C‐terminal region, including H172 of AGP, play important roles in α‐helix formation in the interaction of the protein with biomembranes. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Identification of a high‐affinity binding site for dinotefuran in the nerve cord of the American cockroach
Authors: Miyagi Satoshi , Komaki Iori , Ozoe Yoshihisa 
Published: February 2006

AbstractThe binding of the neonicotinoid insecticide dinotefuran to insect nicotinic acetylcholine receptors (nAChRs) was examined by a centrifugation method using the nerve cord membranes of American cockroaches and [3H]dinotefuran (78 Ci mmol−1). The Kd and Bmax values of [3H]dinotefuran binding were estimated to be 13.7 nM and 14.8 fmol 40 µg−1 protein respectively by Scatchard analysis. Epibatidine, an nAChR agonist, showed a rather lower affinity to the dinotefuran binding site (IC50 = 991 nM) than dinotefuran (IC50 = 5.02 nM). Imidacloprid and nereistoxin displayed lower potencies than dinotefuran but higher potencies than epibatidine. The potencies of five dinotefuran analogues in inhibiting the specific binding of [3H]dinotefuran to nerve cord membranes were determined. A good correlation (r2 = 0.970) was observed between the −log IC50 values of the tested compounds and their piperonyl butoxide‐synergised insecticidal activities (−log LD50 values) against German cockroaches. The results indicate that a high‐affinity binding site for dinotefuran is present in the nerve cord of the American cockroach and that the binding of ligands to the site leads to the manifestation of insecticidal activity. Copyright © 2006 Society of Chemical Industry
Comparative toxicity of Rosmarinus officinalis L. essential oil and blends of its major constituents against Tetranychus urticae Koch (Acari: Tetranychidae) on two different host plants
Authors: Miresmailli Saber , Bradbury Rod , Isman Murray B 
Published: February 2006

AbstractBioassays of Rosmarinus officinalis L. essential oil and blends of its major constituents were conducted using host‐specific strains of the two‐spotted spider mite, Tetranychus urticae Koch, on bean and tomato plants. Two constituents tested individually against a bean host strain and five constituents tested individually against a tomato host strain accounted for most of the toxicity of the natural oil. Other constituents were relatively inactive when tested individually. Toxicity of blends of selected constituents indicated a synergistic effect among the active and inactive constituents, with the presence of all constituents necessary to equal the toxicity of the natural oil. Copyright © 2006 Society of Chemical Industry
Application of linear fracture mechanics to notched timber elements
Authors: Leicester R H 
Published: February 2006

AbstractThe application of linear elastic fracture mechanics is ideally suited to estimating the strength of notched timber elements because wood is quite brittle with respect to tension across the grain. Elements with notches more than a few millimetres deep behave in a brittle manner. Some of the early research in developing this practical application of linear elastic fracture mechanics is presented.In mathematical terms the stress field in the vicinity of a notch contains at least one and sometimes two stress singularities. The magnitudes of these singularities are defined by stress intensity factors. Crack initiation, associated with a predictable size effect, occurs when these factors reach critical values.This paper gives equations for the stress fields around an orthotropic notch root. It also provides a simple method for computing stress intensity factors and size effects in notched structural elements. Some examples of stress intensity factors for timber elements containing zero and non‐zero angle notches are listed. Critical stress intensity factors for timber, related to density, are given for a series of notch types. Measured effects on strength arising from interactions between loading configurations are also presented. Copyright © 2006 John Wiley & Sons, Ltd.
Silicon‐based light emitters
Authors: Kittler M. , Reiche M. , Arguirov T. , Seifert W. , Yu X. 
Published: February 2006

AbstractA new concept for a Si light emitting diode (LED) capable of emitting efficiently at 1.55 µm or at 1.3 µm, respectively, is proposed. It utilizes radiation from a well‐defined dislocation network created in a reproducible manner by direct Si wafer bonding. The wavelength of the light emitted from the network can be tailored by adjusting the misorientation between the Si wafers. That way dominance of radiation at 1.55 µm (D1 line) or at 1.3 µm (D3 line) was achieved. There are hints that decoration of the dislocations by oxygen enhances the intensity of the D1 radiation. A critical analysis of the light emitter proposed by W. L. Ng et al. [Nature 410, 192 (2001)] using band‐to‐band emission is given. Its application at the above wavelengths would require a few microns thick SiGe layer on top of the Si substrate. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Decrease of dielectric loss in CaCu3Ti4O12 ceramics by La doping
Authors: Feng Lixin , Tang Xiaoming , Yan Yueyue , Chen Xuezhi , Jiao Zhengkuan , Cao Guanghan 
Published: February 2006

AbstractWe have developed a novel route to reduce the dielectric loss of CaCu3Ti4O12 (CCTO) material based on the internal‐barrier‐layer‐capacitance (IBLC) model. By the partial La‐for‐Ca substitution the dielectric loss was suppressed re‐markably while the giant dielectric constant still remains. The sample of Ca0.8La0.2Cu3Ti4O12 exhibits a high dielectric con‐ stant over 3000 and a low dissipation factor below 0.015 at 10 kHz from 180 K to 300 K. The impedance spectroscopy analysis confirms that the decrease of dielectric loss is mainly due to the increase of conductivity in the CCTO grain/subgrain. Our result is expected to be able to promote practical applications. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum transport through finite length double‐walled carbon nanotubes
Authors: Yang Linfeng , Chen Jiangwei , Zhang Jizhou , Zhang Jingchang 
Published: February 2006

AbstractUsing tight binding‐based Green's function approach, we studied the quantum transport property of double‐walled carbon nanotubes (DWNTs). Our calculations show that the transport property is mainly determined by the outer wall; the effect of inter‐wall interaction on quantum conductance is quite different for commensurate and incommensurate DWNTs in ideal contacts case: the conductance oscillations vs. Fermi energy only exist in commensurate DWNTs, the quantum conductance step still exists in incommensurate DWNTs except for few deep dips, which result from the antiresonance with edge states in inner tube. In the nonideal electrical contacts cases, however, the conductance oscillations can be induced in both the commensurate and incommensurate DWNTs. The slow background oscillation of the fast conductance oscillations can also be seen if the outer wall is not zigzag type. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic structure of Sb monolayers on the Mo(110) surface
Authors: Proskurin D. , Nikolaychik A. , Koval I. F. , Yakovkin I. N. 
Published: February 2006

AbstractWe compare theory and experimental (LEED and EELS) studies of the atomic and electronic structure of adsorbed Sb layers on Mo(110). At half a monolayer coverage, Sb atoms occupy the “long‐bridge” (hollow) sites forming the (1 × 2) film structure. At this coverage, a dramatic decrease of surface density of states in vicinity of Fermi level results in a quasi dielectric state of the surface. With increasing coverage, direct lateral interaction between Sb atoms becomes increasingly important and leads to push‐out of some Sb atoms in the (2 × 3/2) surface unit cell from the adsorption sites that are favorable at lower coverages. Substantial overlap of orbitals of neighboring adatoms results in metallic state of adsorbed Sb film, as suggested from significant increase of DOS at Fermi level. In EEL spectra, the nonmetal to metal transition reveals itself also by appearance of the –7.8 eV peak, which may be explained by the interband transition from Sb s band to unoccupied p states above EF. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of surface piezoelectricity on the electromechanical behaviour of a piezoelectric ring
Authors: Huang Gan‐Yun , Yu Shou‐Wen 
Published: February 2006

AbstractA relation on electric field dependent surface stress, or alternatively surface piezoelectricity, is proposed in this paper. Based on such relation, a piezoelectric ring under prescribed potential has been studied and the results show that the surface piezoelectricity may play an important role in the electromechanical behavior of piezoelectric nanostructures. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Double‐pole approximation in time‐dependent density functional theory
Authors: Appel H. , Gross E. K. U. , Burke K. 
Published: February 2006

AbstractA simple approximate solution to the linear response equations of time‐dependent density functional theory (TDDFT) is given. This extends the single‐pole approximation (SPA) to two strongly coupled poles.The analysis provides both an illustration of how TDDFT works when strong exchange‐correlation effects are present and insight into such corrections.For example, interaction can cause a transition to vanish entirely from the optical spectrum. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Host‐defence skin peptides of the Australian Streambank Froglet Crinia riparia: isolation and sequence determination by positive and negative ion electrospray mass spectrometry
Authors: Maselli Vita M. , Bilusich Daniel , Bowie John H. , Tyler Michael J. 
Published: February 2006

AbstractA combination of positive and negative ion electrospray mass spectrometry (ES‐MS) together with automated Edman sequencing has been used to determine the amino acid sequences of the host‐defence peptides from the skin glands of the froglet Crinia riparia. The peptides are called riparins. Of the eight peptides isolated, five are neuropeptides containing intramolecular disulfide linkages; e.g. the major peptide riparin 1.4 (FFLPPCAYKGTC‐OH). Positive ion ES‐MS identifies the five residues of riparin 1.4 outside the disulfide moiety, but provides no information on the sequence within the disulfide ring. In contrast, the negative ion dissociations of the [M–H]− ion of riparin 1.4 identify the S‐S link by loss of H2S2 from the [M–H]− ion, and also provide the sequence within the disulfide unit. Other peptides are riparin 2.1 [(IIEKLVNTALGLLSGL‐NH2), a narrow‐spectrum antibiotic], signiferin 3.1 [(GIAEFLNYIKSKA‐NH2), an nNOS inhibitor] and riparin 5.1 [IVSYPDDAGEHAHKMG‐NH2], which shows no neuropeptide, antibiotic or nNOS activity. Copyright © 2006 John Wiley & Sons, Ltd.
Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry with size‐exclusion chromatographic fractionation for structural characterization of synthetic aliphatic copolyesters
Authors: Adamus Grażyna , Rizzarelli Paola , Montaudo Maurizio S. , Kowalczuk Marek , Montaudo Giorgio 
Published: February 2006

AbstractWe report matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) and off‐line coupling of size‐exclusion chromatography with MALDI‐TOFMS analysis (SEC/MALDI‐TOFMS) methods for the detailed characterization of poly[(R,S)‐3‐hydroxybutyrate‐co‐L‐lactic acid], P[(R,S)‐3HB‐co‐LA], and poly[(R,S)‐3‐hydroxybutyrate‐co‐ε‐caprolactone], P[(R,S)‐3HB‐co‐CL], copolymer samples which are expected to be used in special medical application as scaffolds for cartilage and soft tissue engineering. The novel copolyesters contained randomly distributed (R,S)‐3‐hydroxybutyrate structural units, were synthesized by transesterification of the corresponding homopolymers, i.e. atactic poly[(R,S)‐3‐hydroxybutyrate], a‐PHB, and poly(L‐Lactide) (PLLA) or poly(ε‐caprolactone) (PCL), respectively. The MS methods used for the characterization of the resulting polydisperse copolyester samples were supported by classical methods (NMR, SEC). The structures of individual copolyester macromolecules, including end‐group chemical structures, were established using initially MALDI‐TOFMS and then SEC/MALDI‐TOFMS. The compositions of the copolyesters were determined by two methods, namely based on 1H NMR and MALDI‐TOF spectra. The two sets of values showed good agreement. The sequence distribution was determined using the signal intensities of individual copolyester macromolecules, which appeared in MALDI‐TOF mass spectra. Furthermore, sequence analysis gave information about the degree of transesterification. The copolyesters synthesized, with only one exception, were demonstrated to be almost random, which implies that the ester‐ester exchange was close to completion. Copyright © 2006 John Wiley & Sons, Ltd.
Macrocyclic effect of auxiliary ligand on the gas‐phase dissociation of ternary copper(II)–GGX complexes
Authors: Lam Cory N. W. , Siu S. O. , Orlova Galina , Chu Ivan K. 
Published: February 2006

AbstractPrevious studies into the dissociation of [CuII(dien)peptide].2+ ions (dien = diethylenetriamine) have shown that NH‐containing auxiliary ligands do not favor the formation of [peptide].+ species; instead, they promote proton‐transfer reactions, especially for peptides containing basic amino residues. Formation of radical cationic tripeptides of the form GGX.+ [GGX = glycylglycyl(residue X)] becomes feasible upon substituting the open‐chain tridentate ligand dien with its analogous cyclic ligand, 1,4,7‐triazacyclononane (9‐aneN3); i.e., from [CuII(9‐aneN3)GGX].2+ ions. Similar enhancements occur when using 1,4,7,10‐tetraoxacyclododecane (12‐crown‐4) in place of its open‐chain analog, 2,5,8,11‐tetraoxadecane (triglyme). We have demonstrated that a sterically encumbered auxiliary macrocyclic ligand within [CuII(L)GGX].2+ complex ions [where L = 9‐aneN3 or 12‐crown‐4] facilitates the formation of radical cationic peptides through gas‐phase fragmentation. We verified our experimental observations by examining the reactivities of a series of 19 tripeptides of the type GGX that differ only in the identity of their C‐terminal residue. The energy of the electron‐transfer reaction correlates well with the bond‐dissociation energy of the peptide–Cu(II) interaction; the presence of a constrained macrocyclic ligand weakens metal–peptide chelation through steric repulsion between the ligand and the peptide, and this situation may lead to more favorable radical cationic peptide formation. Copyright © 2006 John Wiley & Sons, Ltd.
A novel 14C‐postlabeling assay using accelerator mass spectrometry for the detection of O6‐methyldeoxy‐guanosine adducts
Authors: Tompkins Elaine M. , Farmer Peter B. , Lamb John H. , Jukes Rebekah , Dingley Karen , Ubick Esther , Turteltaub Kenneth W. , Martin Elizabeth A. , Brown Karen 
Published: February 2006

AbstractAccelerator mass spectrometry (AMS) is currently one of the most sensitive methods available for the trace detection of DNA adducts and is particularly valuable for measuring adducts in humans or animal models. However, the standard approach requires administration of a radiolabeled compound. As an alternative, we have developed a preliminary 14C‐postlabeling assay for detection of the highly mutagenic O6‐methyldeoxyguanosine (O6‐MedG), by AMS. Procedures were developed for derivatising O6‐MedG using unlabeled acetic anhydride. Using conventional liquid chromatography/mass spectrometry (LC/MS) analysis, the limit of detection (LOD) for the major product, triacetylated O6‐MedG, was 10 fmol. On reaction of O6‐MedG with 14C‐acetic anhydride, using a specially designed enclosed system, the predominant product was 14C‐di‐acetyl O6‐MedG. This change in reaction profile was due to a modification of the reaction procedure, introduced as a necessary safety precaution. The LOD for 14C‐di‐acetyl O6‐MedG by AMS was determined as 79 amol, ∼18 000‐fold lower than that achievable by liquid scintillation counting (LSC). Although the assay has so far only been carried out with labeled standards, the degree of sensitivity obtained illustrates the potential of this assay for measuring O6‐MedG levels in humans. Copyright © 2006 John Wiley & Sons, Ltd.
Development of a liquid chromatography/tandem mass spectrometry method for the simultaneous determination of 16 mycotoxins on cellulose filters and in fungal cultures
Authors: Delmulle B. , De Saeger S. , Adams A. , De Kimpe N. , Van Peteghem C. 
Published: February 2006

AbstractThe development of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the simultaneous determination of 16 mycotoxins possibly related to the ‘Sick Building Syndrome’ on filters and in fungal cultures is described. Fungi‐surface sampling as regards the ‘Sick Building Syndrome’ preferably happens by scraping off fungal material and vacuuming onto cellulose filters. Therefore, these two media were used as samples. They were spiked with nivalenol, deoxynivalenol, zearalenone, diacetoxyscirpenol, T‐2 toxin, verrucarol, verrucarin A, neosolaniol, sterigmatocystin, roridin A, ochratoxin A, aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatoxin G2, which can be produced by isolates from fungi‐damaged buildings. Deepoxy‐deoxynivalenol was used as internal standard. Samples were extracted with organic solvents and the different mycotoxins were separated by high‐performance liquid chromatography (HPLC) using a C18 reversed‐phase SunFire analytical column and a mobile phase of variable mixtures of ammonium acetate (10 mM) and sodium acetate (20 µM) in water (solvent A) and in methanol (solvent B). The samples were run on‐line with a Micromass Quattro Micro triple quadrupole mass spectrometer in positive electrospray ionisation mode using multiple reaction monitoring (MRM). The detection limits of the procedure varied from 50 to 0.009 pg/µL for filter samples and from 75 to 0.04 pg/µL for fungal culture samples. As the method includes few and non‐labourious sample treatment steps, it should allow for a high throughput of samples. Copyright © 2006 John Wiley & Sons, Ltd.
Fragmentation of the deprotonated ions of peptides containing cysteine, cysteine sulfinic acid, cysteine sulfonic acid, aspartic acid, and glutamic acid
Authors: Men Lijie , Wang Yinsheng 
Published: February 2006

AbstractWe examined the fragmentation of the electrospray‐produced [M–H]− and [M–2H]2− ions of a number of peptides containing two acidic amino acid residues, one being aspartic acid (Asp) or glutamic acid (Glu), and the other being cysteine sulfinic acid [C(SO2H)] or cysteine sulfonic acid [C(SO3H)], on an ion‐trap mass spectrometer. We observed facile neutral losses of H2S and H2SO2 from the side chains of cysteine and C(SO2H), respectively, whereas the corresponding elimination of H2SO3 from the side chain of C(SO3H) was undetectable for most peptides that we investigated. In addition, the collisional activation of the [M–H]− ions of the C(SO2H)‐containing peptides resulted in the cleavage of the amide bond on the C‐terminal side of the C(SO2H) residue. Moreover, collisional activation of the [M–2H]2− ions of the above Asp‐containing peptides led to the cleavage of the backbone N‐Cα bond of the Asp residue to give cn and/or its complementary [zn–H2O] ions. Similar cleavage also occurred for the singly deprotonated ions of the otherwise identical peptides with a C‐terminal amide functionality, but not for the [M–H]− ions of same peptides with a free C‐terminal carboxylic acid. Furthermore, ab initio calculation results for model cleavage reactions are consistent with the selective cleavage of the backbone N–Cα bond in the Asp residue. Copyright © 2006 John Wiley & Sons, Ltd.
H2O‐δD‐FeIII relations of dehydrogenation and dehydration processes in magmatic amphiboles
Authors: Demény Attila , Vennemann Torsten W. , Harangi Szabolcs , Homonnay Zoltán , Fórizs István 
Published: February 2006

AbstractStable isotope compositions of a suite of magmatic amphiboles from alkaline basalts and andesitic rocks were examined to constrain the effects of degassing processes on the hydrogen isotope compositions. The Fe3+ (as Fe3+/Fetotal) and H2O contents, as well as the H isotope compositions of the amphiboles, differ markedly (27–58%, 0.5–2.2 wt%, −107 to −15‰, respectively) but indicate systematic variations. The observed trends can be explained either as dehydrogenation or dehydration processes, both of which are coupled to oxidation processes, the latter most probably related to O2− substitution within amphiboles. The dehydrogenation‐dehydration models can be used to assess the primary compositions of the magmas. As an important example, δD values of amphiboles of Martian meteorites are discussed in a similar context. Copyright © 2006 John Wiley & Sons, Ltd.