bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Four Commercially Available Epstein-Barr Virus Enzyme Immunoassays with an Immunofluorescence Assay as the Reference Method
Authors: Gärtner Barbara C. , Hess Ralf D. , Bandt Dirk , Kruse Alexander , Rethwilm Axel , Roemer Klaus , Mueller-Lantzsch Nikolaus
Published: January 2003

Four commercially available enzyme immunoassays (EIAs) (Novitec, Biotest, Virotech, and DiaSorin) were evaluated, with an indirect immunofluorescence assay as the reference method, for Epstein-Barr virus (EBV) VCA (viral capsid antigen) immunoglobulin G (IgG), VCA IgM, or EBNA (EBV nuclear antigen) IgG at three different locations (Homburg, Stuttgart, and Dresden). Serum samples from 66 immunocompetent patients with infectious mononucleosis, 73 patients without prior EBV infection, and 96 patients with past EBV infections and 29 serum samples with possible cross-reactions to other herpesviruses were included. In addition, 25 samples from an extensively pretested panel that is commercially available (Boston Biomedica) were tested. Each sample was tested at only one location. The four EIAs varied considerably in performance. When analyzing for EBV diagnosis, the Novitec assay performed the best, with 4.9% discrepant diagnoses, followed by the Biotest, Virotech, and DiaSorin assays, with 6.8, 11.7, and 14.0% discrepant diagnoses, respectively. On the basis of single-parameter analysis, the Novitec assay also showed the lowest number of discrepant results, with 3.5%, compared with the Virotech, Biotest, and DiaSorin assays, which produced 5.4, 6.4, and 8.6% discrepant results, respectively. VCA assays using affinity-purified native antigens performed better than assays with recombinant or synthetic antigens. The synthetic EBNA-1s showed the lowest concordance with the reference compared to recombinant p72. Commercially available EBV EIAs differed considerably in performance; however, some proved to be reliable and convenient alternatives to the indirect immunofluorescence assay for routine diagnostics. Native antigens, rather than synthetic peptides, are favored for EBV serology testing.
Measurement ofChlamydia pneumoniae-Specific Immunoglobulin A (IgA) Antibodies by the Microimmunofluorescence (MIF) Method: Comparison of Seven Fluorescein-Labeled Anti-Human IgA Conjugates in an In-House MIF Test Using One Commercial MIF and One Enzyme Immunoassay Kit
Authors: Paldanius Mika , Bloigu Aini , Leinonen Maija , Saikku Pekka
Published: January 2003

For the serological diagnosis of acuteChlamydia pneumoniaeinfection, the microimmunofluorescence (MIF) test is the most commonly used method and also the “gold standard” for the measurement of immunoglobulin G (IgG) and IgM antibodies. The role of IgA antibodies in diagnosis has not been established. Commercially available fluorescein-labeled anti-human IgA conjugates have not been systematically compared to each other, and this situation may cause considerable variations in IgA results. Therefore, we tested 261 serum samples from 122 patients with pneumonia for IgA antibodies by using six α-chain-specific anti-IgA conjugates in our in-house MIF test, one commercial MIF test, and one enzyme immunoassay (EIA). Interfering IgG antibodies were removed with Gullsorb reagent before the measurement of IgA antibodies. Altogether, 14 significant IgA antibody increases in serum samples between the acute phase and the convalescent phase were detected by at least one of the conjugates in the MIF test, while no increases were found in the IgA EIA. Only one patient showed a significant IgA antibody increase with all of the fluorescein-labeled conjugates. Five significant titer changes were detected by at least two conjugates, and in nine instances, the titer increase was detected by one conjugate only. The titer agreement indicated by kappa coefficients was very good or good for all of the fluorescein-labeled conjugates and the EIA with low antibody titers but decreased with increasing titers.
COMPACT STARS: A CORE-ENVELOPE MODEL
Authors: SHARMA R. , MUKHERJEE S.
Published: January 2003

Vaidya–Tikekar20 model has been generalised to describe cold compact stars having concentric layers of different phases. We illustrate the model by considering a star whose inner core has a deconfined quark phase, enveloped by less compact baryonic constituents.
RELATIVISTIC MEAN FIELD PLUS BCS APPROACH TO DRIP-LINE NUCLEI
Authors: YADAV H. L. , SUGIMOTO S. , TOKI H.
Published: January 2003

Based on a relativistic mean field (RMF) framework, we analyze the BCS approximation to the relativistic Hartree–Bogoliubov (RHB) approach for the case of nuclei close to the drip line. In the BCS calculations the single particle continuum corresponding to RMF is replaced by a set of discrete positive energy states generated by enclosing the nucleus in a box. It is found that the main contribution to the pairing correlations for the neutron-rich nuclei is given by the low-lying resonant states, in addition to the contributions coming from the states close to the Fermi surface. Towards this end we present the results of our calculations for the entire chain of even–even 48–98Ni isotopes. Results for the neutron-rich nucleus 84Ni is discussed in detail as a prototype. A detailed comparison of our results for the nucleus 84Ni with those obtained in similar studies using RHB, nonrelativistic Hartree–Fock–Bogoliubov (HFB), and a recently proposed resonant continuum HF+BCS method provides strong evidence for the applicability of the RMF+BCS approach for the treatment of neutron-rich nuclei as well. Additional results of extensive calculations for the isotopes of O, Ca, Zr, Sn and Pb nuclei further reinforce our conclusions. From amongst these calculations, the results of the even–even 32–76Ca isotopes with two different RMF force parametrizations, and their agreement with the recent continuum relativistic Hartree–Bogoliubov (CRHB) results are discussed briefly for illustration purposes.
CONSISTENTLY COMPUTING THE K → π LONG DISTANCE WEAK TRANSITION
Authors: LOWE J. , SCADRON M. D.
Published: January 2003

First we extract the long-distance (LD) weak matrix element <π|HW|K> from K → 2π, K → 3π, KL→ 2γ, K+→ π+e+e-, K+→ π+μ+μ-and KL→ μ+μ-data and give compatible theoretical estimates. We also link this LD scale to the single-quark-line (SQL) transition scale βWand then test the latter SQL scale against the decuplet weak decay amplitude ratio <π-Ξ0| HW|Ω->/<Ξ-|HW|Ω->. Finally, we study LD KS→ 2γ decay. All of these experimental and theoretical values for <π|HW|K> are in good agreement. We deduce an average value from 11 experimental determinations of <π|HW|K> = (3.59 ± 0.05) × 10-8GeV2, while the theoretical SQL values average to (3.577 ± 0.004) × 10-8GeV2.
EQUATION OF STATE OF STRONGLY COUPLED HAMILTONIAN LATTICE QCD AT FINITE DENSITY
Authors: UMINO YASUO
Published: January 2003

We calculate the equation of state of strongly coupled Hamiltonian lattice QCD at finite density by constructing a solution to the equation of motion corresponding to an effective Hamiltonian describing the ground state of the theory with Wilson fermions. To lowest order in N c we find that the pressure of the quark Fermi sea can be negative indicating its mechanical instability. This new mean field result is in qualitative agreement with continuum models and should be verifiable by future numerical simulations.
A SIMPLE SYMMETRY OF THE MONOPOLE HARMONICS
Authors: FUNG M. K.
Published: January 2003

We give a formulation unifying the discussion of the spherical harmonics and the monopole harmonics. As a demonstration of the potency of this approach, we exhibit via this method a symmetry of the exchange of the quantum numbers m and q in the monopole harmonics.
STABILITY FOR STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS WITH DIRICHLET WHITE-NOISE BOUNDARY CONDITIONS
Authors: ALÒS ELISA , BONACCORSI STEFANO
Published: January 2003

In this paper we study the long-time behaviour a stochastic parabolic equation perturbed through the boundary; the perturbation is represented by a nonhomogeneous Dirichlet boundary condition of white-noise type. The existence of the solution for an equation of this kind was the object of a previous paper of the same authors. The estimates proved therein allow to study the asymptotic properties of the solution; we show that there exists a unique invariant measure that is exponentially mean square stable.
INFINITE-DIMENSIONAL GENERALIZED CONTINUED FRACTIONS, DISTRIBUTION OF QUADRATIC RESIDUES AND NON-RESIDUES, AND ERGODIC THEORY
Authors: PUSTYL'NIKOV L. D.
Published: January 2003

A new theory of generalized continued fractions for infinite-dimensional vectors with integer components is constructed. The results of this theory are applied to the classical problem on the distribution of quadratic residues and non-residues modulo a prime number and are based on the study of ergodic properties of some infinite-dimensional transformations.
Yeltsin and Gorbachev: The Politics of Confrontation
Authors: Zlotnik Marc
Published: January 2003

The confrontation between Mikhail Gorbachev and Boris Yeltsin was a key factor in the collapse of the Soviet Union. Perhaps no event of comparable magnitude has been more affected by the personal interactions of two men. The history of the Gorbachev-Yeltsin relationship during the ªnal years of the USSR is largely the story of the collapse of the Soviet state. The passionate dislike and animosity that developed between the two leaders made compromise difªcult and accelerated the collapse of the union. Gorbachev's initial unwillingness to deal seriously with the new Russian leader probably did more to contribute to the disintegration of the Soviet Union than did Yeltsin's bluster and thirst for revenge. It was only when the tables were turned after the failed coup of August 1991, and when Yeltsin clearly had gained control of the situation, that he allowed his intense dislike of Gorbachev to drive his actions.
A Molecular Colour Sensor for Fluoride
Authors: Ward Christopher J , Patel Prakash , James Tony D
Published: January 2003

An azo dye molecule with a boronic acid receptor unit has been used to create a fluoride selective colour sensor.
Electroreduction of Dioxygen Using Co–Ru Dinuclear Porphyrin Catalyst in Nafion Film
Authors: Imaoka Takane , Nakazawa Shinsuke , Yamamoto Kimihisa
Published: January 2003

The mixing of CoTPPS with RuTMPyP (Figure 1) in water or organic solvents (DMSO, acetonitrile) results in dimerization through an electrostatic interaction. The dimeric porphyrin acts as an excellent catalyst for the 4-electron reduction of dioxygen in Nafion film, in which the multi-electron transfer is accelerated through the π-orbital overlapping.
Synthesis of Pyrene-Bearing Oligothiophenes as Novel Light Emitting Materials and Their Application to Single-Organic-Layer Electroluminescence Devices
Authors: Aso Yoshio , Okai Takashi , Kawaguchi Yohei , Otsubo Tetsuo
Published: January 2003

Ter- and quaterthiophenes bearing pyrenes at the terminal α or β positions have been synthesized as novel emitting materials in organic electroluminescence devices. The efficient single-layer EL devices of these compounds are fabricated by use of an Al/ultrathin LiF bilayer cathode. One of them exhibits a maximum luminance of 1860 cd/m2 and a luminous efficiency of 0.15 lm/W, which are of the highest performance class among single-organic-layer EL devices.
An Efficient Method for the p-Methoxybenzylation of Hydroxy Groups with 2-(4-Methoxybenzyloxy)-3-nitropyridine
Authors: Nakano Masakazu , Kikuchi Wataru , Matsuo Jun-ichi , Mukaiyama Teruaki
Published: January 2003

2-(4-Methoxybenzyloxy)-3-nitropyridine (PMBONPy), easily prepared from 2-chloro-3-nitropyridine and p-methoxybenzyl (PMB) alcohol, reacts with various types of hydroxy groups in the presence of a catalytic amount of trimethylsilyl triflate (Me3SiOTf) to give the corresponding PMB ethers in high yields under mild conditions.
Ring Opening Reactions of Cyclic α,β-Epoxysilanes with BF3·Oet2
Authors: Kira Kazunobu , Isobe Minoru
Published: January 2003

Stereospecific ring opening reactions of cyclic α,β-epoxysilanes are described. The reaction pathways are governed by the conformation of the cation intermediates in oxepane.
Solvent and Pressure Dependence of the Energy Profile for the Thermal Fading of a Merocyanine Formed from a Spironaphthoxazine
Authors: Osako Hiroyuki , Kono Hiroharu , Sasaki Makoto , Takahashi Toru , Ohga Yasushi , Asano Tsutomu
Published: January 2003

Activation volumes, activation enthalpies and activation entropies were measured for the thermal fading of a merocyanine formed from a spironaphthoxazine in methyl acetate and ethanol. All of the activation parameters clearly demonstrated that the energy profile was different in these two solvents.
One-Dimensional Zigzag Chain Structures with Intermolecular C–H···π and C–H···O Interactions Consisted of Phthalic Acid and Pyridine Derivatives
Authors: Tomura Masaaki , Yamashita Yoshiro
Published: January 2003

Crystal structures of co-crystals of phthalic acid with 4,4′-bipyridine or 4,4′-dipyridylacetylene contain one-dimensional zigzag chains connected by intermolecular O–H···N hydrogen bonds and edge-to-face packing of phthalic acid and pyridine rings stabilized by intermolecular C–H···π and C–H···O interactions.
TG–MS Analysis of Dehydrochlorination of Poly(vinylidene chloride)
Authors: Akama Tetsuhiro , Yoshioka Toshiaki , Suzuki Toyonobu , Uchida Miho , Okuwaki Akitsugu
Published: January 2003

Poly(vinylidene chloride) (PVDC) was decomposed by thermal treatment to 800 °C under inert atmosphere, using thermogravimetry-mass spectrometry (TG–MS). The evolvement of hydrogen chloride was still observed at 800 °C for the degradation of PVDC. The dehydrochlorination process was divided into two stages according to difference in the formation rate of hydrogen chloride and trichlorobenzene. Dehydrochlorination was accompanied by the evolvement of trichlorobenzene during the first stage below 380 °C, but trichlorobenzene was not observed during the second stage above 380 °C.
New Titanium Complexes Having Two Indolide-Imine Chelate Ligands for Living Ethylene Polymerization
Authors: Matsugi Tomoaki , Matsui Shigekazu , Kojoh Shin-ichi , Takagi Yukihiro , Inoue Yoshihisa , Fujita Terunori , Kashiwa Norio
Published: January 2003

Three new titanium complexes having two indolide-imine ligands were synthesized and investigated as ethylene polymerization catalysts. These complexes using MAO as a cocatalyst promoted ethylene polymerization at 25 °C to produce polyethylenes (Mn:11000–41800) having narrow molecular weight distributions (Mw/Mn: 1.11–1.14), displaying very high activities (52–288 kg-PE/mol-Ti·h·atm).
An Efficient Method for the Conversion of 2-Bromo-5-tosylpyrroles to the Corresponding 5-Tosylpyrrolinones as the D-Ring of Phycocyanobilin Derivatives
Authors: Takeda Shuzo , Jayasundera Krishanthi Padmarani , Kakiuchi Takashi , Kinoshita Hideki , Inomata Katsuhiko
Published: January 2003

2-Bromo-5-tosylpyrroles were efficiently converted to the corresponding 5-tosylpyrrolinones as the D-ring of phycocyanobilin (PCB) derivatives by treating with DMSO and Zn in TFA in the presence of a catalytic amount of iodine. PCB derivatives modified at the D-ring were prepared in free acid forms employing the resulting 5-tosylpyrrolinones toward structure/function analysis of phytochrome.
Adjoint sensitivity of the forecast to TOVS observations
Authors: Fourri'e Nadia , Doerenbecher Alex , Bergot Thierry , Joly Alain
Published: January 2003

The adjoint sensitivity to observations which is based on the adjoint operator of the variational assimilation process is used here on ten cases of the Fronts and Atlantic Storm‐Track EXperiment (FASTEX), conducted in January and February 1997. It is used as a diagnostic tool allowing one to indicate which TIROS‐N (Television Infrared Observation Satellite) Operational Vertical Sounder (TOVS) channels have an influence on the forecast of mid‐latitude lows. In order to study the effects of the observations on the modification of the forecast from the guess, a particular cost function has been chosen: the energy of the difference between the forecast derived from the guess and the one resulting from the analysis. The first part of the paper deals with the sensitivity to the assimilated TOVS observations for the intensive observation period 17 of FASTEX. Then, the influence of TOVS data is compared with one of the other conventional datasets assimilated at the same time. After that, these results are generalized in an overview of the ten studied cases. This study highlights that the Microwave Sounder Unit and clear sky or partly cloudy High‐resolution Infra‐Red Sounder have the larger influence of the TOVS observations on the modification of the forecast. However, the other conventional data have a larger absolute contribution than the TOVS ones. Copyright © 2002 Royal Meteorological Society.
Large‐scale non‐turbulent dynamics in the atmosphere
Authors: Cullen M. J. P.
Published: January 2003

Classical two‐dimensional turbulence theory is often used to understand large‐scale atmospheric flows. However, the equations governing classical two‐dimensional turbulence can only be derived from the governing equations by assuming that the horizontal scale is much smaller than the deformation radius, which is the scale on which baroclinic instability takes place. Typically, the large‐scale quasi‐two‐dimensional disturbances have the vertical depth‐scale of the troposphere and are of larger scale than the baroclinic waves which maintain them. It is therefore more appropriate to study the quasi‐two‐dimensional disturbances with a model appropriate to scales larger than the deformation radius. The semi‐geostrophic model is an accurate model in this regime. It is shown that it does not permit the enstrophy cascades associated with classical two‐dimensional turbulence. This agrees with other results in the literature suggesting that two‐dimensional flow on scales larger than the deformation radius is essentially non‐turbulent. The observed quasi‐permanently unsteady behaviour of the atmosphere thus represents the natural internal dynamics, and does not require explanation by anisotropic forcing. In the ocean, on the other hand, the external deformation radius, which governs the behaviour of two‐dimensional eddies, is much larger than the internal deformation radius, which determines the scale of baroclinic development. It may thus be appropriate to use two‐dimensional turbulence as a model for scales between the internal and external deformation radius. Copyright © 2002 Royal Meteorological Society.
Comparison of TMI rainfall estimates and their impact on 4D‐Var assimilation
Authors: Marécal Virginie , Mahfouf Jean‐françois , Bauer Peter
Published: January 2003

The objectives of this paper are to perform a comparison between three rainfall‐rate estimates from Tropical Rainfall Measuring Mission Microwave Imager (TMI) data and to study their impact in the European Centre for Medium‐Range Weather Forecasts (ECMWF) four‐dimensional variational (4D‐Var) assimilation system. The three algorithms for rainfall estimation considered are: Precipitation Radar Adjusted TMI Estimation of Rainfall (PATER), Bayesian Algorithm for Microwave‐based Precipitation Retrieval (BAMPR‐P), and the National Aeronautics and Space Administration operational algorithm 2A12 level 5.

Results from the comparison show that BAMPR‐P and 2A12 retrievals provide on average higher rain rates by about a factor of 1.5 with respect to PATER, mainly because of the different spatial resolutions and rain detection methods used in the three algorithms. The three TMI products are then compared to the rainfall rates from the ECMWF model. Globally, the rain occurrence simulated by the ECMWF model is higher than in TMI estimates. The model also produces lower rainfall rates in precipitating systems. PATER retrievals are generally closer to the model than those from other algorithms.

Three 15‐day assimilation experiments (‘Rain‐PATER’, ‘Rain‐BAMPR‐P’ and ‘Rain‐2A12’) were run using the three TMI rainfall‐rate estimates in the ECMWF 4D‐Var assimilation system. Fairly small differences were found between the global analyses and forecasts from all experiments and a control experiment without rainfall‐data assimilation. This is explained by the small number of TMI rain observations which are used per assimilation cycle compared to the other types of observational data. The local impact on analyses was studied in two cases, namely a tropical cyclone (‘Bonnie’) and a midlatitude front propagating into the subtropics. For these two cases, the differences between the three TMI products and their associated errors lead to significant changes in the humidity and wind analyses. Copyright © 2002 Royal Meteorological Society.
Smoothing forecast ensembles with fitted probability distributions
Authors: Wilks D. S.
Published: January 2003

Forecast ensembles from the European Centre for Medium‐Range Weather Forecasts Ensemble Prediction System for surface‐weather variables are smoothed by fitting Gaussian distributions. The possibility of bifurcation or other non‐Gaussian behaviours in an ensemble is allowed for by including probability mixtures of two Gaussian distributions when justified by the data. Variables that are clearly non‐Gaussian (wind speed and cloud cover) are transformed before fitting, and multivariate data with dimensions as high as four are considered. The smoothed ensembles provide more‐accurate quantile and probability estimates in a perfect‐model setting, particularly for small ensemble sizes and more‐extreme events. This advantage increases in the presence of random errors in the ensemble means, but diminishes for underdispersed ensembles. Allowing representation of ensembles as Gaussian mixtures also leads to a sharper ‘spread–skill’ relationship in the data considered. Copyright © 2002 Royal Meteorological Society.
SLICE: A Semi‐Lagrangian Inherently Conserving and Efficient scheme for transport problems
Authors: Zerroukat Mohamed , Wood Nigel , Staniforth Andrew
Published: January 2003

A Semi‐Lagrangian Inherently Conserving and Efficient (SLICE) scheme is described for transport of passive scalars in Cartesian geometry. It is based on a Control‐Volume (CV) approach and uses multiple sweeps of a one‐dimensional O(Δx4) conservative remapping algorithm along pre‐determined cascade directions. The scheme is applied to standard two‐dimensional tests from the literature. Overall, it is found that in addition to conserving mass exactly, it is also competitive with standard non‐conserving semi‐Lagrangian schemes from the viewpoints of both computational efficiency and accuracy. © Crown Copyright, 2002.
Suction Caisson Foundations for Offshore Wind Turbines
Authors: Byrne Byron , Houlsby Guy , Martin Chris , Fish Peter
Published: January 2003

This paper outlines a £ 1.5m, three year, research project that commenced during the middle of 2002 to determine a design framework for shallow foundations for offshore wind turbines. The shallow foundations in focus are suction-installed skirted foundations otherwise known as suction caissons (Houlsby and Byrne, 2000). There are eight distinct themes to the research covering all aspects of the geotechnical performance of these foundations. The funding for the project has been obtained from the Department of Trade and Industry (£ 917k), Industrial Partners (£ 373k) and the Engineering and Physical Sciences Research Council (£ 221k). The results will feed into the design process for offshore wind turbines almost immediately.
Bayesian Analysis Applied to Statistical Uncertainties of Extreme Response Distributions of Offshore Wind Turbines
Authors: Cheng P.W. , van Kuik G.A.M. , van Bussel G.J.W. , Vrouwenvelder A.C.W.M.
Published: January 2003

Extreme response is an important design variable for wind turbines. The statistical uncertainties concerning the extreme response distribution are simulated here with data concerning physical characteristics obtained from measurements. The extreme responses are the flap moment at the blade root and the overturning moment of the support structure of an offshore wind turbine situated in the North Sea. The statistical uncertainties concern the choice of the distribution model and uncertainties concerning the distribution parameters. The uncertainties are treated with Bayesian analysis. The inclusion of the uncertainties has only marginal effect for the calculated long-term estimates of extreme responses when non-informative priors for the distribution parameters are used. The inclusion of uncertainties may have larger effect if data concerning the moments are obtained from measurements.
Variable-speed Wind Turbines with Doubly-fed Induction Generators Part II: Power System Stability
Authors: Akhmatov Vladislav
Published: January 2003

This article describes the second part of a larger investigation of dynamic interaction between variable-speed wind turbines equipped with doubly-fed induction generators (DFIG) and the power grid. A simulation model is applied for dynamic stability investigations, with the entire power grid subjected to a short-circuit fault. During the grid disturbances, the DFIG converter is found to be the most sensitive part of the wind turbine. Therefore the electrical currents are determined using the transient generator model. The converter action is crucial for wind turbine operation associated with such disturbances, especially regarding tripping or uninterrupted operation.
Aspects of alkali treatment of sponge gourd (Luffa cylindrica) fibers on the flexural properties of polyester matrix composites
Authors: Boynard C. A. , Monteiro S. N. , d'Almeida J. R. M.
Published: January 2003

Sponge gourd (Luffa cylindrica) forms a natural mat that deviates the crack path in brittle thermoset resin matrix composites, leading to a controlled fracture mode and increasing the toughness of the composite. The use of luffa as reinforcement is, however, restricted by a very weak fiber–matrix interface. In this work, luffa fibers were alkali‐treated at two temperatures, with varying alkali concentrations. Although the surface analysis shows that the treatments promote a clear removal of the outer surface layer of the fibers with the exposition of the inner fibrillar structure and the consequent increase of the fiber surface area, only a secondary increase on the mechanical properties was obtained. The slight increase observed was attributed only to mechanical interlock. Long pullout lengths and neat fiber beads were the main features observed at the fracture surface of the treated and untreated fiber composites. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1927–1932, 2003
Swelling characterizations of chitosan and polyacrylonitrile semi‐interpenetrating polymer network hydrogels
Authors: Kim Seon Jeong , Shin Su Ryon , Lee Young Moo , Kim Sun I.
Published: January 2003

Temperature‐ and pH‐responsive semi‐interpenetrating polymer network (semi‐IPN) hydrogels constructed with chitosan and polyacrylonitrile (PAN) were studied. The characterizations of semi‐IPN hydrogels were investigated using Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). IPN hydrogels exhibited a relatively high swelling ratio, 23.31%–145.20% at room temperature. The swelling ratio of hydrogels depends on pH and temperature. DSC was used to determine the amount of free water in IPN hydrogels. The amount of free water increased with increasing chitosan content in the semi‐IPN hydrogels. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2011–2015, 2003
Cover Picture: ChemBioChem 1/2003
Authors: Sidhu Sachdev S. , Fairbrother Wayne J. , Deshayes Kurt
Published: January 2003

The cover picture shows a highly diverse peptide library displayed on cylindrical bacteriophage particles that also contain the cognate DNA. Libraries such as this can be used to identify specific ligands for essentially any protein of interest. Here, phage particles displaying peptides that bind vascular endothelial growth factor are selected from amongst a sea of billions of random sequences. Further information can be found in the Review by Sidhu and co‐workers on p. 14 ff. (We thank David Wood and Christian Wiesmann for help in the preparation of the cover picture.)
Analysis of Protein Tyrosine Kinase Inhibitors in Recombinant Yeast Lacking the ERG6 Gene
Authors: Clark Daniel D. , Peterson Blake R.
Published: January 2003

Studies of small‐molecule–protein interactions in yeast can be hindered by the limited permeability of yeast to small molecules. This diminished permeability is thought to be related to the unique sterol composition of fungal membranes, which are enriched in the steroid ergosterol. We report the construction of the novel Saccharomyces cerevisiae yeast strain DCY250, which is compatible with yeast two‐hybrid‐based systems and bears a targeted disruption of the ERG6 gene to ablate ergosterol biosynthesis and enhance permeability to small molecules. The small‐molecule inhibitors of protein tyrosine kinases (PTKs) PP1, PP2, herbimycin A, and staurosporine were investigated with yeast tribrid systems that detect the activity of the PTKs v‐Abl and v‐Src. These tribrid systems function by expression of the PTK, a B42 activation domain fused to the phosphotyrosine‐binding Grb2 SH2 domain, a DNA‐bound LexA‐GFP‐(AAYANAA)4 universal PTK substrate, and a lacZ reporter gene. Yeast genetic systems that lack functional ERG6 were found to be as much as 20‐fold more sensitive to small‐molecule inhibitors of PTKs than systems with ERG6, and these deficient systems may provide a useful platform for the discovery and analysis of small‐molecule–protein interactions.
Exploring Protein–Protein Interactions with Phage Display
Authors: Sidhu Sachdev S. , Fairbrother Wayne J. , Deshayes Kurt
Published: January 2003

Protein–protein interactions mediate essentially all biological processes. A detailed understanding of these interactions is thus a major goal of modern biological chemistry. In recent years, genome sequencing efforts have revealed tens of thousands of novel genes, but the benefits of genome sequences will only be realized if these data can be translated to the level of protein function. While genome databases offer tremendous opportunities to expand our knowledge of protein–protein interactions, they also present formidable challenges to traditional protein chemistry methods. Indeed, it has become apparent that efficient analysis of proteins on a proteome‐wide scale will require the use of rapid combinatorial approaches. In this regard, phage display is an established combinatorial technology that is likely to play an even greater role in the future of biology. This article reviews recent applications of phage display to the analysis of protein–protein interactions. With combinatorial mutagenesis strategies, it is now possible to rapidly map the binding energetics at protein–protein interfaces through statistical analysis of phage‐displayed protein libraries. In addition, naïve phage‐displayed peptide libraries can be used to obtain small peptide ligands to essentially any protein of interest, and in many cases, these binding peptides act as antagonists or even agonists of natural protein functions. These methods are accelerating the pace of research by enabling the study of complex protein–protein interactions with simple molecular biology methods. With further optimization and automation, it may soon be possible to study hundreds of different proteins in parallel with efforts comparable to those currently expended on the analysis of individual proteins.
Total Enantioselective Synthesis and In Vivo Biological Evaluation of a Novel Fluorescent BODIPY α‐Galactosylceramide
Authors: Vo‐Hoang Yen , Micouin Laurent , Ronet Catherine , Gachelin Gabriel , Bonin Martine
Published: January 2003

Natural killer T (NKT) cells are a distinct subset of mature lymphocytes endowed with features of activated and regulatory T cells. α‐Galactosylceramides (α‐GalCers), the synthetic prototype of which is KRN7000, are the only natural reagents recognised by the T‐cell receptor of NKT cells. The α‐GalCer‐activated NKT cells promptly release IFNγ and IL‐4 (IFN=interferon; IL=interleukin) and undergo apoptotic death within hours. In mice, activated NKT cells are responsible for antitumour activity and protection against autoimmune diseases. KRN7000 can thus be considered as the root of a family of novel immunoregulatory drugs. To get insights into the in vivo behaviour of α‐galactosylceramides, an original fluorescent derivative has been prepared by following a convergent synthetic scheme. This strategy allows the introduction of different acyl chains, carbohydrate residues and various labels in the final steps of the synthesis. The fluorescent BODIPY probe derived from a versatile glycolipid precursor is as active as KRN7000 for inducing apoptosis of liver NKT cells. Fluorescence was detected in peritoneal macrophages and splenic antigen‐presenting cells, in Kupffer‐like cells in the liver, but not in lymphocytes.
Assembly of Designed Oligonucleotides as an Efficient Method for Gene Recombination: A New Tool in Directed Evolution
Authors: Zha Dongxing , Eipper Andreas , Reetz Manfred T.
Published: January 2003

A new and practical method for gene recombination with formation of libraries of mutant genes is presented. The method is based on the assembly of appropriately prepared oligonucleotides whose design is guided by sequence information. High recombination frequency with formation of full‐length products is achieved by controlled overlapping of the designed oligomers. This process (ADO) minimizes self‐hybridization of parental genes, which constitutes a significant advantage over conventional family shuffling as used in the directed evolution of functional enzymes. ADO was applied to the recombination of two lipase family genes from Bacillus subtilis (LipA and LipB). In a library of 3000 lipase variants created by this method, several were found that display increased enantioselectivity in a model reaction involving the hydrolysis of a meso‐diacetate.
Solution Structure and Stability of Tryptophan‐Containing Nucleopeptide Duplexes
Authors: Gómez‐Pinto Irene , Marchán Vicente , Gago Federico , Grandas Anna , González Carlos
Published: January 2003

Covalently linked peptide–oligonucleotide hybrids were used as models for studying tryptophan–DNA interactions. The structure and stability of several hybrids in which peptides and oligonucleotides are linked through a phosphodiester bond between the hydroxy group of a homoserine (Hse) side chain and the 3′‐end of the oligonucleotide, have been studied by both NMR and CD spectroscopy and by restrained molecular dynamics methods. The three‐dimensional solution structure of the complex between Ac‐Lys‐Trp‐Lys‐Hse(p3′dGCATCG)‐Ala‐OH (p=phosphate, Ac=acetyl) and its complementary strand 5′dCGTAGC has been determined from a set of 276 experimental NOE distances and 33 dihedral angle constraints. The oligonucleotide structure is a well‐defined duplex that belongs to the B‐form family of DNA structures. The covalently linked peptide adopts a folded structure in which the tryptophan side chain stacks against the 3′‐terminal guanine moiety, which forms a cap at the end of the duplex. This stacking interaction, which resembles other tryptophan–nucleobase interactions observed in some protein–DNA complexes, is not observed in the single‐stranded form of Ac‐Lys‐Trp‐Lys‐Hse(p3′dGCATCG)‐Ala‐OH, where the peptide chain is completely disordered. A comparison with the pure DNA duplex, d(5′GCTACG3′)–(5′CGTAGC3′), indicates that the interaction between the peptide and the DNA contributes to the stability of the nucleopeptide duplex. The different contributions that stabilize this complex have been evaluated by studying other nucleopeptide compounds with related sequences.
Design of a Composite Ethidium–Netropsin–Anilinoacridine Molecule for DNA Recognition
Authors: Carrasco Carolina , Helissey Philippe , Haroun Michelyne , Baldeyrou Brigitte , Lansiaux Amélie , Colson Pierre , Houssier Claude , Giorgi‐Renault Sylviane , Bailly Christian
Published: January 2003

Control of gene expression is a cherished goal of cancer chemotherapy. Small ligand molecules able to bind tightly to DNA in a well‐defined configuration are being actively searched for. With this goal in mind, we have designed and synthesized the trifunctional molecule R‐132, which combines a bispyrrole skeleton for minor groove DNA recognition and two different chromophores, anilinoacridine and ethidium. The affinity and mode of binding of R‐132 to DNA were studied by a combination of complementary biochemical and biophysical techniques, which included absorption and fluorescence spectroscopy and circular and linear dichroism. A surface plasmon resonance biosensor analysis was also performed to quantify the kinetic parameters of the drug–DNA interaction process. Altogether, the results demonstrate that the three moieties of the hybrid molecule are engaged in the interaction process, thus validating the rational design strategy. At the biological level, R‐132 stabilizes topoisomerase‐II–DNA covalent complexes and displays potent cytotoxic activities, which are attributable to its DNA‐binding properties. R‐132 easily enters and accumulates in cell nuclei, as evidenced by confocal microscopy. R‐132 therefore provides a novel lead compound for the design of gene‐targeted anticancer agents.
Synthesis and Biological Activity of a Platinum(II) 6‐Phenyl‐2,2′‐bipyridine Complex and Its Dimeric Analogue
Authors: Chan Hing‐Leung , Ma Dik‐Lung , Yang Mengsu , Che Chi‐Ming
Published: January 2003

We have synthesized (pyridyl)‐(6‐phenyl‐2,2′‐bipyridine)platinum(II) hexafluorophosphate (1) and its corresponding dimer, μ‐N,N′‐bis(isonicotinyl)‐1,6‐hexanediamino bis‐[6‐phenyl‐2,2′‐bipyridine‐platinum(II)] dichloride (2). The DNA binding constants of 1 and 2 at 20 °C were determined by absorption titration to be 2.25×104 M−1 and 3.07×106 M−1, respectively. Compound 1 showed an AT preference, while 2 had no base preference. The binding site sizes of 2 for [poly(dA‐dT)]2, calf thymus DNA (ctDNA), and [poly(dG‐dC)]2, as determined by fluorescence titration, were 6.6, 4.0, and 2.8 bp, respectively. Compound 2 probably bound to [poly(dA‐dT)]2 through bisintercalation, and to [poly(dG‐dC)]2 by monointercalation. Binding of DNA by both complexes is favorable, since the binding free energies of 1 and 2 were estimated to be −5.8 and −8.7 kcal mol−1, respectively. The results of viscosity measurements and gel mobility shift assay demonstrated that binding of 1 and 2 caused DNA lengthening. The cytotoxicities of the complexes in various human cancer cell lines were determined by MTT assay. Complex 2 exhibited cytotoxicity comparable to that of cisplatin, and was more toxic than 1 by an order of magnitude.
Synthesis and Biological Evaluation of Pyrazolylnaphthoquinones as New Potential Antiprotozoal and Cytotoxic Agents
Authors: Sperandeo Norma R. , Brun Reto
Published: January 2003

The importance of American trypanosomiasis (Chagas' disease) in human pathology is widely known. The prognosis of this disease is poor and the choice of effective medicines limited, thus study of new drugs is absolutely necessary. In this work, the activities of three new pyrazolylnaphthoquinones, heterocyclic naphthoquinones bearing 3‐aminopyrazole rings, were evaluated on Trypanosoma cruzi, the etiological agent of Chagas' disease. These activities were compared with those of three 5‐aminoisoxazole analogues. In addition, since these compounds belong to a family of antiprotozoal and cytotoxic/antitumor agents, the activities of all six against Plasmodium falciparum, Trypanosoma brucei rhodesiense, and murine L‐6 cells were also investigated. In the biological tests, five of the compounds showed significant in vitro trypanocidal activities against T. cruzi, with activities similar to that of benznidazole. Two of the 5‐aminoisoxazole analogues also showed good activities, in one case highly selective, against the K1 and NF54 strains of P. falciparum (IC50<0.12 μg mL−1). Three of the compounds were cytotoxic to murine L‐6 cells (IC50=0.21–0.50 μg mL−1). The results suggested that the three pyrazolylnaphthoquinones and one of the 5‐aminoisoxazole analogues could be starting points for lead optimization programs against T. cruzi and P. falciparum, respectively.
Conformational Features of Human Melanin‐Concentrating Hormone: An NMR and Computational Analysis
Authors: Vitale Rosa Maria , Zaccaro Laura , Di Blasio Benedetto , Fattorusso Roberto , Isernia Carla , Amodeo Pietro , Pedone Carlo , Saviano Michele
Published: January 2003

The conformational features of human melanin‐concentrating hormone (hMCH) [Asp1‐Phe2‐Asp3‐Met4‐Leu5‐Arg6‐cyclo(SS)(Cys7‐Met8‐Leu9‐Gly10‐Arg11‐Val12‐Tyr13‐Arg14‐Pro15‐Cys16)‐Trp17‐Gln18‐Val19], in water and in a CD3CN/H2O (1:1 v/v) mixture at 298 K, have been determined by NMR spectroscopy followed by simulated annealing and molecular dynamics analyses to identify conformer populations. Backbone clustering analysis of NMR‐spectroscopy‐derived structures in the 7–16 peptide region led to the identification of a single representative structure in each solvent. Both root mean square deviation clustering and secondary structure analysis of the final conformers in both solvents show substantial convergence of most conformers into a single fold in the 4–17 region, with a limited variability around Gly10 and Tyr13 on going from CD3CN/H2O to pure water. The main feature deduced from the analysis of secondary structures is the occurrence of an N‐terminalαhelix of variable length, which spans an overall residue range of 2–9. A comparative analysis in the two solvents highlights that these structures are substantially different from that reported in the literature for the cyclic MCH(5–14) subunit of salmon MCH, which was used to perform a molecular characterization of the MCH/receptor complex. Our conformational data call for a critical revision of the proposed MCH/receptor complex model.
Optimization of Electrochemical and Peroxide‐Driven Oxidation of Styrene with Ultrathin Polyion Films Containing Cytochrome P450cam and Myoglobin
Authors: Munge Bernard , Estavillo Carmelita , Schenkman John B. , Rusling James F.
Published: January 2003

The catalytic and electrochemical properties of myoglobin and cytochrome P450cam in films constructed with alternate polyion layers were optimized with respect to film thickness, polyion type, and pH. Electrochemical and hydrogen peroxide driven epoxidation of styrene catalyzed by the proteins was used as the test reaction. Ionic synthetic organic polymers such as poly(styrene sulfonate), as opposed to SiO2 nanoparticles or DNA, supported the best catalytic and electrochemical performance. Charge transport involving the iron heme proteins was achieved over 40–320 nm depending on the polyion material and is likely to involve electron hopping facilitated by extensive interlayer mixing. However, very thin films (ca. 12–25 nm) gave the largest turnover rates for the catalytic epoxidation of styrene, and thicker films were subject to reactant transport limitations. Classical bell‐shaped activity/pH profiles and turnover rates similar to those obtained in solution suggest that films grown layer‐by‐layer are applicable to turnover rate studies of enzymes for organic oxidations. Major advantages include enhanced enzyme stability and the tiny amount of protein required.
Novel Trifluoromethyl Ketones as Potent Gastric Lipase Inhibitors
Authors: Kokotos George , Kotsovolou Stavroula , Verger Robert
Published: January 2003

Novel inhibitors of human digestive lipases, lipophilic trifluoromethyl ketones, were developed. These analogues of the natural triacylglycerol substrates of lipases were designed to contain the carbonyl group of the trifluoromethyl ketone functionality in place of the carbonyl group of the scissile ester bond at the sn‐1 position. The ester bond at the sn‐3 position was replaced by an ether bond, while the secondary hydroxy group was either esterified or etherified. The inhibitors were prepared starting from solketal. The inhibition of human pancreatic and gastric lipases by the trifluoromethyl ketones was studied by the monolayer technique. 5,5,5‐Trifluoro‐1‐(dodecyloxymethyl)‐4‐oxopentyl decanoate is the best synthetic inhibitor of human gastric lipase ever reported (inhibition constant α50=0.003).
Evaluation of Lipopolysaccharide Aggregation by Light Scattering Spectroscopy
Authors: Santos Nuno C. , Silva Ana C. , Castanho Miguel A. R. B. , Martins‐Silva J. , Saldanha Carlota
Published: January 2003

Lipopolysaccharides (LPS) are cell wall components of Gram‐negative bacteria. These molecules behave as bacterial endotoxins and their release into the bloodstream is a determinant of the development of a wide range of pathologies. These amphipathic molecules can self‐aggregate into supramolecular structures with different shapes and sizes. The formation of these structures occurs when the LPS concentration is higher than the apparent critical micelle concentration (CMCa). Light scattering spectroscopy (both static and dynamic) was used to directly characterize the aggregation process of LPS from Escherichia coli serotype 026:B6. The results point to a CMCa value of 14 μg mL−1 and the existence of premicelle LPS oligomers below this concentration. Both structures were characterized in terms of molecular weight (5.5×106 and 16×106 g mol−1 below and above the CMCa, respectively), interaction with the aqueous environment, gyration radius (56 and 105 nm), hydrodynamic radius, (60 and 95 nm) and geometry of the supramolecular structures (nearly spherical). Our data indicates that future in vitro experiments should be carried out both below and above the CMCa. The search for drugs that interact with the aggregates, and thus change the CMCa and condition LPS interactions in the bloodstream, could be a new way to prevent certain bacterial‐endotoxin‐related pathologies.
Successful experiences with making partnering an operational strategy
Authors: Buettner David L. , Morrison Michael C. , Wasicek Margery
Published: January 2003

A series of partnerships at North Iowa Area Community College have been founded on concepts critical to longterm success. The benefits extend beyond increased resources to make partnering an operational strategy.
Building partnerships with business that make a difference
Authors: Sundberg Lori L.
Published: January 2003

The Center for Manufacturing Excellence, which houses a business incubator and provides many creative ideas for workforce development programs, has made a significant impact on its community.
Developing successful community partnerships: “Teeing up” for change
Authors: Tyler Arthur Q.
Published: January 2003

Building a golf driving range on an urban community college campus provides an example of entrepreneurial partnering with a private developer. This project reconnected the campus and community cultures and helped reenergize the faculty and staff.
A community college partnership with an electrical contractor and union
Authors: Allen John P.
Published: January 2003

This nationally acclaimed partnership, built around an apprentice program and based on a foundation of trust and cooperation, illustrates how a trade union and a community college can find a way to use a mutual interest to benefit students and workers.
Asnuntuck community college's machine technology certificate and degree programs
Authors: Irlen Harvey S. , Gulluni Frank D.
Published: January 2003

A partnership of public agencies and small, private sector manufacturers squarely confronts the challenge of educating men and women in the field of manufacturing technology.
The Alameda Corridor Industry & College Collaborative
Authors: Bynum Lou Anne
Published: January 2003

A community‐college‐and‐industry‐based partnership formed in response to a large public works project in a depressed region of Los Angeles County faced the challenges of developing an outreach and career‐path program for hard‐to‐serve clients in a short time span.
Learning into action: Partnerships take the classroom to the community
Authors: Woiwod Linda P.
Published: January 2003

This chapter describes the faculty‐imitated development of experimental projects with community agencies and businesses as a core requirement for transfer students to become engaged with both their campus and their community.