bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative analysis of neonicotinoid binding to insect membranes: II. An unusual high affinity site for [3H]thiamethoxam in Myzus persicae and Aphis craccivora
Authors: Wellmann Henning , Gomes Marilyne , Lee Connie , Kayser Hartmut 
Published: June 2004

AbstractNeonicotinoids represent a class of insect‐selective ligands of nicotinic acetylcholine receptors. Imidacloprid, the first commercially used neonicotinoid insecticide, has been studied on neuronal preparations from many insects to date. Here we report first intrinsic binding data of thiamethoxam, using membranes from Myzus persicae Sulzer and Aphis craccivora Koch. In both aphids, specific binding of [3H]thiamethoxam was sensitive to temperature, while the absolute level of non‐specific binding was not affected. In M persicae, binding capacity (Bmax) for [3H]thiamethoxam was ca 450 fmol mg−1 of protein at 22 °C and ca 700 fmol mg−1 of protein at 2 °C. The negative effect of increased temperature was reversible and hence not due to some destructive process. The affinity for [3H]thiamethoxam was less affected by temperature: Kd was ca 11 nM at 2 °C and ca 15 nM at 22 °C. The membranes also lost binding sites for [3H]thiamethoxam during prolonged storage at room temperature, and upon freezing and thawing. In A craccivora, [3H]thiamethoxam was bound with a capacity of ca 1000 fmol mg−1 protein and an affinity of ca 90 nM, as measured at 2 °C. Overall, the in vitro temperature sensitivity of [3H]thiamethoxam binding was in obvious contrast to the behaviour of [3H]imidacloprid studied in parallel. Moreover, the binding of [3H]thiamethoxam was inhibited by imidacloprid in a non‐competitive mode, as shown with M persicae. In our view, these differences demonstrate that thiamethoxam and imidacloprid, which represent different structural sub‐classes of neonicotinoids, do not share the same binding site or mode. This holds also for other neonicotinoids, as we report in a companion article. Copyright © 2004 Society of Chemical Industry
Repellency of aerosol and cream products containing fennel oil to mosquitoes under laboratory and field conditions
Authors: Kim Soon‐Il , Chang Kyu‐Sik , Yang Young‐Cheol , Kim Byung‐Seok , Ahn Young‐Joon 
Published: June 2004

AbstractThe repellency of fennel (Foeniculum vulgare Miller)‐containing products (5% aerosol and 8% cream) against mosquitoes was compared with those of citronella oil, geranium oil and deet, as well as three commercial repellents, Baby Keeper® cream containing IR3535, MeiMei® cream containing citronella and geranium oils, and Repellan S® aerosol containing 19% N,N‐diethyl‐m‐toluamide (deet) under laboratory and field conditions. In a laboratory study with female Aedes aegypti (L), fennel oil exhibited good repellency in a release‐in‐cage test and repellency in skin and patch tests of the oil was comparable with those of citronella and geranium oils. In paddy field tests with five human volunteers, 5% and 8% fennel oil‐containing aerosol and cream produced 84% and 70% repellency, respectively, at 90 min after exposure, whereas Baby Keeper cream and MeiMei cream gave 71% and 57% repellency at 90 min after exposure, respectively, and Repellan S aerosol gave 89% repellency at 210 min. The species and ratio of mosquitoes collected were the genera Culex (44.1%), Anopheles (42.2%), Aedes (7.8%) and Armigeres (5.9%). Fennel oil‐containing products could be useful for protection from humans and domestic animals from vector‐borne diseases and nuisance caused by mosquitoes. Copyright © 2004 Society of Chemical Industry
Cyclic peptides selected by phage display mimic the natural epitope recognized by a monoclonal anti‐colicin A antibody
Authors: Coulon Stephane , Metais Jean‐Yves , Chartier Martine , Briand Jean‐Paul , Baty Daniel 
Published: June 2004

AbstractA 10‐mer random peptide library displayed on filamentous bacteriophage was used to determine the molecular basis of the interaction between the monoclonal anti‐colicin A antibody 1C11 and its cognate epitope. Previous studies established that the putative epitope recognized by 1C11 antibody is composed of amino acid residues 19–25 (RGSGPEP) of colicin A. Using the phage display technique it was confirmed that the epitope of 1C11 antibody was indeed restricted to residues 19–25 and the consensus motif RXXXPEP was identified. Shorter consensus sequences (RXXPEP, RXXEP, KXXEP) were also selected. It was also demonstrated that the disulfide bond found in one group of the selected peptides was crucial for 1C11 antibody recognition. It was shown that cyclization of the peptides by disulfide bond formation could result in a structure that mimics the natural epitope of colicin A. Copyright © 2004 European Peptide Society and John Wiley & Sons, Ltd.
Positronium at polymeric surface
Authors: Rathore M. K. , Shrivastava S. B. , Rathore V. 
Published: June 2004

AbstractAnnihilation of slow positrons at a polymeric surface has been discussed in terms of positron diffusion and trapping of positronium into free volume holes. The above model has been used to calculate the ortho‐positronium lifetime (τ3) in polystyrene (PS), epoxy resin film, polyurethane (PU) and polytetrafluroethylene (PTFE) as a function of temperature, incident positron energy and mean implantation depth. The results have been compared with the experimental observations of other authors. The variation inτ3with respect to temperature clearly demonstrates a discontinuity in the curve atTgcorresponding to the glass transition temperature. The variation of calculatedτ3shows that the lifetime increases significantly aboveTghowever, belowTgit increases only slowly. This is a direct consequence of the change in the size of free volume holes. TheTghas been found to be dependent both on positron energy and density of the polymer. Large variation inτ3has been observed at low energies suggesting a significant structure of free volume holes near the surface. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dielectric relaxation and ionic conductivity studies of the mixed crystal (NH4)3H(SO4)1.42(SeO4)0.58
Authors: Louati B. , Guidara K. , Gargouri M. 
Published: June 2004

AbstractThe temperature and frequency dependent complex impedance of (NH4)3H(SO4)1.42(SeO4)0.58(NHSSe) was measured. The temperature dependence of the electrical conductivity of the sample crystal in the different phases follows the Arrhenius law. The real part of the permittivity constant is analysed in term of a dipole oscillator and the imaginary part with the Cole‐Cole formalism. In the temperature range from 299 to 326 K, the activation energy obtained from complex permittivity (E0 = 0.30 ± 0.03 eV) and modulus spectra (Em = 0.26 ± 0.02 eV) are close, suggesting that the H+ ion transport is probably due to a hopping mechanism. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Use of Wannier‐type atomic orbitals in LCAO and plane wave calculations: Chemical bonding in MgO crystal
Authors: Evarestov R. A. , Smirnov V. P. , Tupitsyn I. I. , Usvyat D. E. 
Published: June 2004

AbstractLCAO and plane wave (PW) DFT calculations of the electronic structure of the ionic crystal MgO are performed. Local characteristics of the electronic structure of this crystal are obtained using the traditional approaches and the method based on Wannier‐type atomic orbitals (WTAOs). It is demonstrated for the first time that the results of the WTAO population analysis for both types of the basis (LCAO and PW) correctly exhibit the ionic nature of chemical bonding in this crystal. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reproducibility of clinical data I: continuous outcomes
Authors: Blackman Nicole Jill‐Marie 
Published: June 2004

AbstractAcross a variety of clinical settings, repeated measurements on an individual, obtained under identical circumstances, often differ from one another. This implies the measurements lack perfect reproducibility. Topics related to reproducibility of clinical measurements are introduced in this paper. In this first of two parts, continuous outcomes are addressed. The intraclass correlation coefficient, ρ, has been the traditional coefficient of reproducibility for continuous outcomes. The importance of ρ regarding observations on an individual, and observations among populations, is outlined. Estimation and inferential procedures for ρ are reviewed and worked examples are provided. Copyright © 2004 John Wiley & Sons, Ltd.
Reproducibility of clinical data II: categorical outcomes
Authors: Blackman Nicole Jill‐Marie 
Published: June 2004

AbstractIn this second part of this paper, reproducibility of discrete ordinal and nominal outcomes is addressed. The first part deals with continuous outcomes, concentrating on intraclass correlation (ρ) in the context of one‐way analysis of variance. For categorical data, the focus has generally not been on a meaningful population parameter such as ρ. However, intraclass correlation has been defined for discrete ordinal data, ρc, and for nominal data, κI. Therefore, a unified approach to reproducibility is proposed. The relevance of these parameters is outlined. Estimation and inferential procedures for ρc and κI are reviewed, together with worked examples. Topics related to reproducibility that are not addressed in either this or the previous paper are highlighted. Considerations for designing reproducibility studies and for interpreting their results are provided. Copyright © 2004 John Wiley & Sons, Ltd.
The analysis of the AB/BA cross‐over trial in the medical literature
Authors: Senn Stephen , Lee Sally 
Published: June 2004

AbstractThe evolution of opinion as to how to analyse the AB/BA cross‐over trials is described by examining the recommendations of three key papers. The impact of these papers on the medical literature is analysed by looking at citation rates as a function of various factors. It is concluded that amongst practitioners there is a highly imperfect appreciation of the issues raised by the possibility of carry‐over. Copyright © 2004 John Wiley & Sons, Ltd.
Adjusted homogeneity tests of odds ratios when data are clustered
Authors: Song James X. 
Published: June 2004

AbstractThree modified tests for homogeneity of the odds ratio for a series of 2 × 2 tables are studied when the data are clustered. In the case of clustered data, the standard tests for homogeneity of odds ratios ignore the variance inflation caused by positive correlation among responses of subjects within the same cluster, and therefore have inflated Type I error. The modified tests adjust for the variance inflation in the three existing standard tests: Breslow–Day, Tarone and the conditional score test. The degree of clustering effect is measured by the intracluster correlation coefficient, ρ. A variance correction factor derived from ρ is then applied to the variance estimator in the standard tests of homogeneity of the odds ratio. The proposed tests are an application of the variance adjustment method commonly used in correlated data analysis and are shown to maintain the nominal significance level in a simulation study. Copyright © 2004 John Wiley & Sons, Ltd.
Determination of glycopeptide structures by multistage mass spectrometry with low‐energy collision‐induced dissociation: comparison of electrospray ionization quadrupole ion trap and matrix‐assisted laser desorption/ionization quadrupole ion trap reflectron time‐of‐flight approaches
Authors: Demelbauer Uwe M. , Zehl Martin , Plematl Alexander , Allmaier Günter , Rizzi Andreas 
Published: June 2004

AbstractMultistage mass spectrometry, as implemented using low‐energy collision‐induced dissociation (CID) analysis in three‐dimensional (3D) quadrupole ion traps (QITs), has become a powerful tool for the investigation of protein glycosylation. In addition to the well‐known combination of QITs with electrospray ionization (ESI), also a matrix‐assisted laser desorption/ionization—quadrupole ion trap—reflectron time‐of‐flight (MALDI‐QIT‐rTOF) mass spectrometer has recently become available. This study systematically investigates the differences between these types of instrument, as applied to characterization of glycopeptides from human antithrombin. The glycopeptides were obtained by tryptic digestion followed by lectin‐affinity purification. Some significant differences between the ESI‐QIT and MALDI‐QIT‐rTOF approaches appeared, most of them are causally related to the desorption/ionization process. The combination of a vacuum MALDI source with an ion‐trap analyzer accentuates some characteristic differences between MALDI and ESI due the longer time frame needed for the trapping process. In contrast to ESI, MALDI generated ions that exhibited considerable metastable fragmentation during trapping. The long time span of the QIT process (ms range) compared with that for conventional rTOF experiments (μs range) significantly magnified the extent of this metastable fragmentation. With the investigated glycopeptides, a complete depletion of the terminal sialic acids of the glycopeptides as well as a variety of other fragment ions was already found in the MS1 spectra from the MALDI‐QIT‐rTOF instrument. The positive ion low‐energy CID spectra (MS2) of the selected glycopeptides obtained using the two different QIT equipped instruments were found to be quite similar. In both approaches, fragmentation of the glycan and peptide structures occurred sequentially, allowing unambiguous sequence determination. In the case of ESI‐QIT‐MS, fragmentation of the glycan structure occurred at the MS2 stage and fragmentation of the peptide structure was obtained only at the MS3 stage, which indicates the necessity of multistage CID experiments for complete structure elucidation. The MALDI‐QIT‐rTOF instrument yielded both kinds of fragments at the MS2 stage but without mutual interference. Copyright © 2004 John Wiley & Sons, Ltd.
Liquid chromatographic analysis of nucleosides and their mono‐, di‐ and triphosphates using porous graphitic carbon stationary phase coupled with electrospray mass spectrometry
Authors: Xing Jinsong , Apedo Atsu , Tymiak Adrienne , Zhao Ning 
Published: June 2004

AbstractAnalysis of nucleosides and nucleotides is desirable in many biological studies, but the task is analytically challenging due to the high polarity of the analytes. In this study, resolution of mixtures containing nucleosides and their mono‐, di‐ and triphosphates was achieved using a porous graphitic carbon (PGC) stationary phase, Hypercarb, under conditions suitable for liquid chromatography/mass spectrometry (LC/MS). Different organic mobile phases and modifiers were evaluated and the separation of 16 nucleosides and nucleotides was optimized using gradient elution with a water/acetonitrile mobile phase containing ammonium acetate and diethylamine as modifiers. The ammonium acetate concentration proved to be critical for retention and diethylamine was found to improve the peak shapes of di‐ and triphosphates for mass spectrometric detection. A variety of silica‐based columns designed for polar compound separation were also tested using optimized LC conditions and compared with results obtained with the Hypercarb column. Only the Hypercarb column provided separations suitable for accurate quantitation of mixed nucleosides and their phosphates. Copyright © 2004 John Wiley & Sons, Ltd.
Electron capture dissociation Fourier transform ion cyclotron resonance mass spectrometry in the electron energy range 0–50 eV
Authors: Tsybin Youri O. , Witt Matthias , Baykut Gökhan , Håkansson Per 
Published: June 2004

AbstractElectron capture dissociation (ECD) of polypeptide cations was obtained with pencil and hollow electron beams for both sidekick and gas‐assisted dynamic ion trapping (GADT) using Fourier transform ion cyclotron resonance mass spectrometry (FTICR‐MS) with an electrostatic ion transfer line. Increasing the number of trapped ions by multiple ICR trap loads using GADT improved the ECD sensitivity in comparison with sidekick ion trapping and ECD efficiency in comparison with single ion trap load by GADT. Furthermore, enhanced sensitivity made it possible to observe ECD in a wide range of electron energies (0–50 eV). The degree, rate and fragmentation characteristics of ECD FTICR‐MS were investigated as functions of electron energy, electron irradiation time, electron flux and ion trapping parameters for this broad energy range. The results obtained show that the rate of ECD is higher for more energetic (>1 eV) electrons. Long electron irradiation time with energetic electrons reduces average fragment ion mass and decreases efficiency of formation of c‐ and z‐type ions. The obtained dependencies suggest that the average fragment ion mass and the ECD efficiency are functions of the total fluence of the electron beam (electron energy multiplied by irradiation time). The measured electron energy distributions in low‐energy ECD and hot ECD regimes are about 1 eV at full width half maximum in employed experimental configurations. Copyright © 2004 John Wiley & Sons, Ltd.
DVB‐S2 low density parity check codes with near Shannon limit performance
Authors: Eroz Mustafa , Sun Feng‐Wen , Lee Lin‐Nan 
Published: June 2004

AbstractLow density parity check (LDPC) codes are chosen for the second generation digital video broadcasting (DVB) standard. In this paper, we review LDPC codes in general, present belief propagation decoding algorithm in simple terms, describe the standardized LDPC codes and show their performance. Copyright © 2004 John Wiley & Sons, Ltd.
DVB‐S2, the second generation standard for satellite broadcasting and unicasting
Authors: Morello Alberto , Reimers Ulrich 
Published: June 2004

AbstractDVB‐S2 is the second‐generation specification for satellite broadcasting developed by the DVB Project in 2003 and needs to be seen in conjunction with the world‐famous DVB‐S specification which was finalized in 1993. It benefits from more recent developments in channel coding (LDPC codes) combined with a variety of modulation formats (QPSK, 8PSK, 16APSK and 32APSK). When used for interactive point‐to‐point applications like IP‐based service navigation, it may implement adaptive coding and modulation (ACM), thus allowing the transmission parameters to be optimized for each individual user, dependent on path conditions. Backwards compatible modes are available, allowing existing DVB‐S services and Set Top Boxes (STBs) to continue working during any transitional period. Copyright © 2004 John Wiley & Sons, Ltd.
DVB‐S2 modem algorithms design and performance over typical satellite channels
Authors: Casini E. , Gaudenzi R. De , Ginesi A. 
Published: June 2004

AbstractIn this paper we propose a design of the main modulation and demodulation units of a modem compliant with the new DVB‐S2 standard (Int. J. Satellite Commun. 2004; 22:249–268). A typical satellite channel model consistent with the targeted applications of the aforementioned standard is assumed. In particular, non‐linear pre‐compensation as well as synchronization techniques are described in detail and their performance assessed by means of analysis and computer simulations. The proposed algorithms are shown to provide a good trade‐off between complexity and performance and they apply to both the broadcast and the unicast profiles, the latter allowing the exploitation of adaptive coding and modulation (ACM) (Proceedings of the 20th AIAA Satellite Communication Systems Conference, Montreal, AIAA‐paper 2002‐1863, May 2002). Finally, end‐to‐end system performances in term of BER versus the signal‐to‐noise ratio are shown as a result of extensive computer simulations. The whole communication chain is modelled in these simulations, including the BCH and LDPC coder, the modulator with the pre‐distortion techniques, the satellite transponder model with its typical impairments, the downlink chain inclusive of the RF‐front‐end phase noise, the demodulator with the synchronization sub‐system units and finally the LDPC and BCH decoders. Copyright © 2004 John Wiley & Sons, Ltd.
Frame synchronization and pilot structure for second generation DVB via satellites
Authors: Sun Feng‐Wen , Jiang Yimin , Lee Lin‐Nan 
Published: June 2004

AbstractDue to the advanced coding schemes utilized in DVB‐S2, new receivers have to function at unprecedented low SNR. From the perspective of synchronization, the major challenges are frame synchronization and carrier recovery. The challenge for frame synchronization arises from the fact that the frames of LDPC are rather long, up to 32 400 symbols, and there is no built‐in structure in the LDPC to facilitate frame synchronization. Carrier recovery becomes a major challenge due to the requirement to retain the current outdoor equipment. This implies that the receivers have to work with the same phase noise as specified for the first generation DVB‐S, which uses only QPSK modulation. DVB‐S2 needs to support QPSK at much lower signal to noise ratios (SNR) and other higher order modulation schemes at about the same SNR of DVB‐S.In this paper, we will describe the solutions to frame synchronization and carrier recovery. Low overhead rapid frame synchronization is achieved by utilizing the physical layer signalling code. Robust carrier recovery is aided by the aggregated pilot structure. The design considerations for the pilot structure and the implementation tradeoffs of the carrier recovery schemes are addressed. Copyright © 2004 John Wiley & Sons, Ltd.
DVB‐S2 backward‐compatible modes: a bridge between the present and the future
Authors: Chen Ernest , Koslov Joshua L. , Mignone Vittoria , Santoru Joseph 
Published: June 2004

AbstractThe second generation Digital Video Broadcasting (DVB) system for satellite broadcasting (DVB‐S2) has been standardized including tools to allow backward compatibility (BC) with the operating standard DVB‐S (EN 300 421, Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for 11/12 GHz satellite services. V.1.1.2, August 1997, http://www.etsi.org). Two conceptual ways of implementing BC have been defined: hierarchical modulation and layered modulation.The paper describes the standardized backward‐compatible modes and presents the results of analytical investigations and simulations of the system in various configurations, as carried out by DIRECTV, Rai‐CRIT and Thomson. Copyright © 2004 John Wiley & Sons, Ltd.
Evaluation of a compiler with user‐selectable execution strategies for parallel recursion
Authors: Mizutani Yasuharu , Nakajima Daisuke , Fujimoto Noriyuki , Hagihara Kenichi 
Published: June 2004

AbstractThe strategy of evenly distributing processors to each recursive call and the strategy of performing dynamic load‐balancing exist as strategies for executing parallel recursions. There are cases in which an execution strategy efficient for a certain parallel recursive algorithm is not efficient for another parallel recursive algorithm depending on the operation of the parallel recursion algorithm. In addition, there are cases in which the execution efficiency decreases due to overparallelization of recursive calls due to factors such as the communication efficiency of a parallel computing environment. On the one hand, it is not easy for a compiler to analyze these factors mechanically from source programs of a parallel recursive algorithm, select an optimal execution strategy, and suppress overparallelization. In general, in many cases, a programmer understands parallel recursive algorithms and can predict which execution strategy is suitable for the algorithm. Thus, if a programmer can specify a parallel recursive execution strategy or specify a decision to suppress overparallelization, parallel recursive algorithms can be executed efficiently. This paper proposes a strategy for a programmer to clearly designate information useful for efficiently executing parallel recursion. In addition, it shows differences in the performance of various execution strategies of parallel recursive algorithms and shows the usefulness of a programmer having the capability to select an execution strategy. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(9): 92–103, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10009