bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of a wideband microstrip array antenna for PCS and IMT‐2000 service
Authors: Kim Taewoo , Choi Jaehoon , Jeon Joo Seong
Published: September 2002

In this letter, a wideband microstrip array antenna for a PCS and IMT‐2000 base station is designed. To obtain the wideband characteristic, we utilized a multilayered structure composed of foam materials and a parasitic element with an aperture‐coupled feeding network. The return‐loss characteristic is improved by placing the gaps between coupling slots. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 261–265, 2001.
Application of ferromagnetic composite in different planar tunable microwave devices
Authors: Salahun E. , Tanné G. , Quéffélec P. , Lefloc'h M. , Adenot A.‐L. , Acher O.
Published: September 2002

In this paper, several microwave devices using a ferromagnetic composite demonstrate great tunability under weak magnetizing field conditions. Indeed, a tunable bandstop of 50% tunability and phase shifters of 35°/dB figure of merit around 3 GHz and 7.8°/dB in the X‐band are obtained when a 250 Oe dc magnetic field is applied. Moreover, a magnetic switch near 25 dB isolation and less than 1 dB insertion losses is realized. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 272–276, 2001.
A dual‐band rectangular microstrip antenna using a novel photonic bandgap ground plane of unequal orthogonal periods
Authors: Kuo Yen‐Liang , Chiou Tzung‐Wern , Wong Kin‐Lu
Published: September 2002

This paper presents a novel photonic bandgap (PBG) structure of unequal orthogonal periods and its application to a dual‐band rectangular microstrip antenna for performance enhancement. The two operating frequencies of the dual‐band microstrip antenna studied have orthogonal polarization planes, and by using the proposed PBG ground plane with its periods in orthogonal directions determined from the two separate operating frequencies, gain enhancements of 1.7 and 1.1 dBi have been obtained for the lower and upper operating frequencies, respectively. Details of the PBG structure studied are described, and the obtained experimental results are presented. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 280–283, 2001.
Decidualization and implantation: Embryo‐uterine bioinformatics at work
Authors: Kierszenbaum Abraham L.
Published: September 2002

The implantation of the blastocyst into a nurturing endometrium involves two overlapping steps: 1. The blastocyst‐endometrial luminal epithelial attachment. 2. The decidualization of the endometrial stroma. An intriguing question is how does the blastocyst identify the uterine implantation site. Current research is focused on hypothetical soluble signaling molecules released by the blastocyst for conditioning a discrete uterine luminal epithelial domain for implantation. A still unresolved issue is the functional significance of receptor autophosphorylation following binding of uterine epithelial cell‐derived heparin‐binding epidermal growth factor‐like growth factor to the epidermal growth factor receptor on trophoectodermic cell surfaces. With recent results hinting at the role of signaling proteins associated with the bone morphogenetic protein, fibroblast growth factor, WNT and hedgehog families to enable embryo implantation, the dynamics of uterine‐embryo interaction becomes linked to fundamental cellular pathways of growth, differentiation and apoptosis. Mol. Reprod. Dev. 59:123–125, 2001. © 2001 Wiley‐Liss, Inc.
Extracellular apparent diffusion in rat brain
Authors: Duong Timothy Q. , Sehy Jonathan V. , Yablonskiy Dmitriy A. , Snider B. Joy , Ackerman Joseph J.H. , Neil Jeffrey J.
Published: September 2002

The apparent diffusion coefficients (ADCs) of a series of markers concentrated in the extracellular space of normal rat brain were measured to evaluate, by inference, the ADC of water in the extracellular space. The markers (mannitol, phenylphosphonate, and polyethylene glycols) are defined as “compartment selective” because tissue culture experiments demonstrate some leakage into the intracellular space, making them less “compartment specific” than commonly believed. These primarily extracellular markers have ADCs similar to those of intracellular metabolites of comparable hydrodynamic radius, suggesting that water ADC values in the intra‐ and extracellular spaces are similar. If this is the case, then it is unlikely that a net shift of water from the extra‐ to the intracellular space contributes significantly to the reduction in water ADC detected following brain injury. Rather, this reduction is more likely due primarily to a reduction of the ADC of intracellular water associated with injury. Magn Reson Med 45:801–810, 2001. © 2001 Wiley‐Liss, Inc.
Region and tissue differences of metabolites in normally aged brain using multislice 1H magnetic resonance spectroscopic imaging
Authors: Schuff Norbert , Ezekiel Frank , Gamst Anthony C. , Amend Diane L. , Capizzano Andres A. , Maudsley Andrew A. , Weiner M.W.
Published: September 2002

Quantitative measurements of regional and tissue specific concentrations of brain metabolites were measured in elderly subjects using multislice proton magnetic resonance spectroscopic imaging (1H MRSI). Selective k‐space extrapolation and an inversion‐recovery sequence were used to minimize lipid contamination and linear regression was used to account for partial volume problems. The technique was applied to measure the concentrations of N‐acetyl aspartate (NAA), and creatine (Cr)‐ and choline (Cho)‐containing compounds in cortical gray and white matter, and white matter lesions of the frontal and the parietal lobe in 40 normal elderly subjects (22 females and 18 males, 56–89 years old, mean age 74 ± 8). NAA was about 15% lower in cortical gray matter and 23% lower in white matter lesions when compared to normal white matter. Cr was 11% higher in cortical gray matter than in white matter, and also about 15% higher in the parietal cortex than in the frontal cortex. Cho was 28% lower in cortical gray matter than in white matter. Furthermore, NAA and Cr changes correlated with age. In conclusion, regional and tissue differences of brain metabolites must be considered in addition to age‐related changes when interpreting 1H MRSI data. Magn Reson Med 45:899–907, 2001. © 2001 Wiley‐Liss, Inc.
Evaluation of age, body mass index, and wrist index as risk factors for carpal tunnel syndrome severity
Authors: Kouyoumdjian Joao A. , Zanetta Dirce M.T. , Morita Maria P.A.
Published: September 2002

To determine the role of personal variables as risk factors for carpal tunnel syndrome (CTS) and their relationship to severity of nerve conduction abnormality, we studied 210 consecutive symptomatic CTS patients and 320 controls subjects without CTS symptomatology or known systemic disorders. The CTS group was classified according to the severity of nerve conduction changes. The risk factors for CTS and its severity were assessed by means of univariate and multivariate analysis. Presence of CTS was significantly related to increase of body mass index (BMI) and wrist index. More severe nerve conduction abnormalities were associated with greater age and wrist index but not with higher BMI. © 2002 John Wiley & Sons, Inc. Muscle Nerve 25: 93–97, 2002
Proposed revised electrophysiological criteria for chronic inflammatory demyelinating polyradiculoneuropathy
Authors: Nicolas Guillaume , Maisonobe Thierry , Le Forestier Nadine , Léger Jean‐Marc , Bouche Pierre
Published: September 2002

Electrophysiological criteria for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) were proposed by an Ad Hoc Subcommittee of the American Academy of Neurology (AAN) in 1991. Only 60% of CIDP patients fulfilled these criteria, which therefore appear poorly sensitive. We therefore sought to revise the electrophysiological criteria. We selected 40 CIDP patients and compared them with 35 patients with axonal polyneuropathy, 116 patients with Charcot‐Marie‐Tooth type 1A (CMT1A) disease, and 66 patients with immunoglobulin M (IgM) monoclonal gammopathy. The proposed electrophysiological criteria identified 90% of the CIDP patients, although 3% of patients with axonal polyneuropathy were falsely identified. For the CIDP patients, sensitivity and specificity were 90% and 97%, respectively. Of the patients with IgM monoclonal gammaglobulin of undetermined significance (MGUS) and CMT1A, 100% fulfilled these new criteria, whereas 90% and 97%, respectively, fulfilled the AAN criteria. These results suggest that the AAN criteria are more appropriate for IgM MGUS and CMT1A patients than for CIDP patients. We therefore propose new electrophysiological criteria for CIDP that appear to have better sensitivity. © 2002 American Association of Electrodiagnostic Medicine Muscle Nerve 25: 26–30, 2002
Analysis of ephrin‐A2 in the chick retinotectal projection using a function‐blocking monoclonal antibody
Authors: Yamada T. , Okafuji T. , Ohta K. , Handwerker C. , Drescher U. , Tanaka H.
Published: September 2002

Eph receptor tyrosine kinases and their ligands have been shown to be involved in processes of cell migration and axon guidance during embryonic development. Here we describe the development of a function‐blocking monoclonal antibody against chick ephrin‐A2, and its effect on retinal ganglion cell axons studied both in vitro and in vivo. In the stripe assay, the blocking antibody completely abolished the repulsive effect of posterior tectal membranes. In vivo, in a loss‐of‐function approach, hybridoma cells secreting the antiephrin‐A2 antibody were applied to chick embryos from embryonic day 3 (E3) on, and the retinotectal projection was subsequently analyzed at E16. DiI tracing analyses showed that although the projection of both temporal and nasal retinal ganglion axons in the tectum was, overall, normal, occasionally diffuse and extra termination zones were observed, in addition to axons over‐shooting their termination zones. These data support the idea that ephrin‐A2 contributes to the establishment of the chick retinotectal projection. © 2001 John Wiley & Sons, Inc. J Neurobiol 47: 245–254, 2001
Knowing is all: or is it? Some reflections on why the acquisition of knowledge, focusing particularly on evaluation activities, does not always lead to action
Authors: Cracknell Basil E.
Published: September 2002

This article examines the factors that influence whether the acquisition of knowledge leads on to action. It looks first at the ‘supply’ side, i.e. the kind of knowledge that is being acquired and whether it meets the needs of the intended users and is conducive to action; whether knowledge is a product or a process; the relevance of the positivist and constructivist approaches in this context; and whether participatory methods are required. The article then turns to the ‘demand’ side, and looks at possible reasons why decision‐takers may often seem to ignore new knowledge and evaluation findings. It suggests that evaluators may sometimes have unrealistic expectations of the kind of impact their reports should have. On the other hand there are factors leading to inertia and risk averseness that may stymie action. The importance of a ‘knowledge culture’ is emphasized if knowledge is to be turned into action. Copyright © 2001 John Wiley & Sons, Ltd.
Angular group‐induced bond alternation (AGIBA). Part 5—Conformation dependence and additivity of the effect: structural studies of 3,5‐dimethoxybenzaldehyde ­derivatives and related systems
Authors: Krygowski Tadeusz M. , Pindelska Edyta , Anulewicz‐Ostrowska Romana , Grabowski Sławomir J. , Dubis Alina T.
Published: September 2002

X‐ray structure analysis of 3,4,5‐trimethoxybenzadehyde and 3,5‐dimethoxy‐4‐(1‐bromoethoxy)benzaldehyde gave their molecular geometries which showed a vague AGIBA effect. To clarify the situation, ab initio optimizations at the MP2/6–31G** level of theory of 12 conformers of 1,3,5‐trimethoxy‐, 1,3‐dimethoxy‐5‐formyl‐, 1,3‐diformyl‐5‐methoxy‐ and 1,3,5‐triformylbenzene derivatives were carried out. The results support the occurrence of additive AGIBA effects, even if some weak interactions are possible between the methoxy and formyl groups. Copyright © 2001 John Wiley & Sons, Ltd.
Olefin epoxidation by dioxiranes and percarboxylic acids: an analysis of activation energies calculated by a density functional method
Authors: Gisdakis Philip , Rösch Notker
Published: September 2002

The activity of dioxiranes, R2CO2, and percarboxylic acids, RCO(O2)H, in olefin epoxidation reactions can be rationalized by a frontier orbital interaction. Barrier heights of these oxygen transfer reactions, as calculated by a density functional method, depend linearly on the energy of the olefin HOMO orbital π (C—C) and of the peroxide LUMO orbital σ*(O—O). Activation barriers can be predicted from linear relationships with the proton affinity of a dioxirane (as measured by the hydrogen fluoride association energy) or the pKa value of a percarboxylic acid. Copyright © 2001 John Wiley & Sons, Ltd.
Enzyme‐catalyzed transesterification of vinyl esters on cellulose solids
Authors: Xie Jiangbing , Hsieh You‐Lo
Published: September 2002

Enzyme‐catalyzed transesterification of several cellulose solids in organic media have been investigated. Several protease enzymes were made soluble in organic media through ion‐paired enzyme–surfactant complexes. Subtilisin Carsberg was found to be catalytically active in the transesterification of cellulose with vinyl propionate and vinyl acrylate in anhydrous pyridine. The ester carbonyl groups in acylated cellulose derivatives were confirmed by Fourier transform infrared spectroscopy. The surfaces of these cellulose derivatives became hydrophobic as demonstrated by increased water‐contact angles. The enzyme‐catalyzed transesterification was confirmed to regioselectively target the primary hydroxyl group of cellulose by reactions on specifically substituted cellulose. The cellulose esters from enzyme‐catalyzed transesterification could be hydrolyzed partially by the same enzyme in aqueous media, and were thus biodegradable. Surface grafting of cellulose acrylate was demonstrated using azobisisobutyronitrile‐initiated polymerization of acrylonitrile in dimethylformamide. Polyacrylonitrile (PAN)‐g‐cellulose shows a different thermal behavior from cellulose, homopolymer PAN, and PAN/cellulose blends. The grafted PAN on PAN‐g‐cellulose at a 16% grafting add‐on is incapable of cyclization. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1931–1939, 2001
Synthesis and polymerization of functionalized dendritic macromonomers
Authors: Vetter Serge , Koch Sabine , Schlüter A. Dieter
Published: September 2002

The synthesis of dendritic building blocks (dendrons) of the first generation (G1) and the second generation, which carry differently protected amine groups in the periphery, is reported. The dendrons are used for the synthesis of the corresponding acrylic and methacrylic macromonomers. Their polymerization behavior under radical conditions is investigated. The G1 dendronized polymers are decorated at their peripheral amino groups, that is, with the chiral amino acid L‐phenylalanine by the attach‐to approach. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1940–1954, 2001
Epoxy–amine reticulates observed by infrared spectrometry. III. Modifications of the structure and hydration abilities after irradiation in a humid atmosphere
Authors: Ngono Yvette , Maréchal Yves
Published: September 2002

This article is the third part of a series devoted to the study of the responsibilities of both humidity and irradiation in the aging process of amine‐cured epoxy resins. The basic technique used in this study was infrared spectrometry. In previous articles, we described the hydration of two kinds of epoxy resins widely used in the nuclear industry. In the first article, we reported results concerning the hydration of unirradiated resins; in the second article, these resins were first submitted to ionizing radiation in a dry atmosphere. In this article, we describe the effects of irradiation in a humid atmosphere and compare these effects to what was observed after irradiation in a dry atmosphere, as described in the previous articles. These effects were subtle: the humidity of the ambient atmosphere apparently protected the resins from oxidative degradation because, after irradiation in a humid atmosphere, a smaller number of carboxylic groups were formed. However, the water uptake increased after irradiation in a humid atmosphere. Thus, the humidity of the ambient atmosphere at the same time favored the rupture of chains, which released steric hindrances and allowed a greater number of H2O molecules to reach hydrophilic sites in the resin. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1129–1136, 2001
Intercalated clay nanocomposites: Morphology, mechanics, and fracture behavior
Authors: Zerda Adam S. , Lesser Alan J.
Published: September 2002

Intercalated nanocomposites of modified montmorillonite clays in a glassy epoxy were prepared by crosslinking with commercially available aliphatic diamine curing agents. These materials are shown to have improved Young's modulus but corresponding reductions in ultimate strength and strain to failure. The results were consistent with most particulate‐filled systems. The macroscopic compressive behavior was unchanged, although the failure mechanisms in compression varied from the unmodified samples. The fracture toughness of these materials was investigated and improvements in toughness values of 100% over unmodified resin were demonstrated. The fracture‐surface topology was examined using scanning electron and tapping‐mode atomic force microscopies and shown to be related to the clay morphology of the system. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1137–1146, 2001
Structural analysis of certain linear operators representing chemical network systems via the existence and uniqueness theorems of spectral resolution. VI*
Authors: Arimoto Shigeru , Spivakovsky Mark , Ohno Hiromu , Zizler Peter , Taylor Keith F. , Yamabe Tokio , Mezey Paul G.
Published: September 2002

The present Part VI of this series of articles provides a mathematical and methodical link between (i) fundamental methodology in the repeat space theory (RST), which is referred to as the approach via the aspect of form and general topology and which has universal unifying power to handle additivity problems of molecules that have many identical moieties, and (ii) frontier electron theory of reactivity indices. Using theoretical tools required to link (i) and (ii), we establish a theorem from which the Generalized Alpha Existence Theorem (a theorem essential in the RST and proved in the previous Part V) directly follows. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 389–400, 2001
A QM/MM/continuum model for computations in solution: Comparison with QM/MM molecular dynamics simulations
Authors: Chalmet S. , Rinaldi D. , Ruiz‐López M. F.
Published: September 2002

We propose a model for fast quantum mechanical computations of molecules and processes in solution. The chemical system is described quantum mechanically (QM) using density functional theory. A few discrete solvent molecules are described using molecular mechanics (MM) force fields. The bulk solvent is described through a dielectric continuum model. The interaction between the QM/MM aggregate and the continuum is computed by using a multipole moment development of the charge distribution of the former. This is an intermediate model between the standard continuum approach and the combined quantum mechanics and molecular mechanics (QM/MM) technique, in which a large number of MM solvent molecules is considered and a statistical simulation of the solution is performed. The method may also be used to estimate long‐range interactions in combined QM/MM Monte Carlo or molecular dynamics simulations. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Improvement of the hybrid density functional method from the viewpoint of effective exchange integrals
Authors: Kitagawa Y. , Soda T. , Shigeta Y. , Yamanaka S. , Yoshioka Y. , Yamaguchi K
Published: September 2002

Spin‐unrestricted hybrid density functional theory (DFT) methods are improved to reproduce potential curves and effective exchange integrals ( Jab) of several diradical models, which were calculated by unrestricted post‐Hartree–Fock methods. Particularly, we attempt to reproduce the Jab value of the UCCSD(T) method by using the DFT methods. In general, the magnitude of the calculated Jab values by the conventional DFT methods for radical dimers was too large in comparison with the post‐Hartree–Fock methods values. To overcome the problem, we improve the DFT method for the intermolecular (through‐space) effective exchange integrals by using the hybrid method. Furthermore, the rule for the hybridization is constructed in terms of instability value ysys of the bonding. © 2001 John Wiley & Sons, Inc. Int J Quant Chem, 2001
Electronic structure calculation by monte carlo diagonalization method
Authors: Shigeta Y. , Nagao H. , Yamaguchi K.
Published: September 2002

We propose an electronic structure calculation scheme for ground and low‐lying excited states of molecular systems by using the generalized coherent state for fermion, where the coefficients of the coherent states are determined by a stochastic approach. This method has both the advantage of the ordinary quantum Monte Carlo and that of the direct diagonalization methods and does not suffer from the negative sign problem. We demonstrate a performance of the present method. © 2001 John Wiley & Sons, Inc. Int J Quant Chem, 2001
Detection of sulfur‐containing impurities in pharmaceutical samples by high performance liquid chromatography/chemical reaction interface mass spectrometry
Authors: Eckers Christine , Abramson Fred P. , Lecchi Paolo
Published: September 2002

This paper describes the use of chemical reaction interface mass spectrometry (CRIMS) combined with liquid chromatography for the detection of trace level sulfur‐containing impurities in pharmaceutical materials. A mixture of sulfur‐ and non‐sulfur‐containing compounds were analyzed initially to test the system. Then the determination of trace level impurities in a cimetidine drug substance was carried out. Detection of sulfur‐containing impurities at less than 0.1% of the major component was obtained with good linearity. The results obtained are consistent with the expected results for this sample and illustrate the applicability of the technique. Copyright © 2001 John Wiley & Sons, Ltd.
On the fragmentation pathway of the ionized enol of glycine in the gas phase
Authors: Marino T. , Russo N.
Published: September 2002

Density functional and second‐order many body perturbation approaches were used to compute the potential energy surface for the fragmentation of the ionized enol of glycine [H2NCH = C(OH)2]+· into water and aminoketene radical cation [H2N‐HC = CO]+·. Two possible pathways were considered. The potential energy surfaces obtained are very similar and both predict the existence of a molecular complex in which the water is coordinated to the aminoketene moiety in two different fashions with a noticeable binding energy. The fragmentation is kinetically controlled by the step in which the molecular complex is formed from the most stable cation enol of glycine. Our quantum‐mechanical data confirm the hypothesis that the ylide ion [H3NCHCOOH]+· is an intermediate in the water loss. Copyright © 2001 John Wiley & Sons, Ltd.
The effect of the source pressure on the abundance of ions of noncovalent protein assemblies in an electrospray ionization orthogonal time‐of‐flight instrument
Authors: Tahallah Nora , Pinkse Martijn , Maier Claudia S. , Heck Albert J. R.
Published: September 2002

The effect of elevating the pressure in the interface region of an electrospray ionization orthogonal time‐of‐flight mass spectrometer on the ion intensity of different noncovalent protein assemblies has been investigated. Elevating the pressure in the interface region generally led to an enhanced detection of high m/z ions. The optimum pressure was found to be dependent on the m/z value of the ions. This pressure effect should be carefully addressed when relating ion abundance in the mass spectra to solution phase abundance of noncovalent protein assemblies. Copyright © 2001 John Wiley & Sons, Ltd.
Electron impact mass spectral interpretation for some thiophosphoryl‐p‐acetylaminobenzenesulfonamides
Authors: Fenesan I. , Popescu Rodica , Supuran C.T. , Nicoara Simona , Culea Monica , Palibroda N. , Moldovan Z. , Cozar O.
Published: September 2002

This work discusses the synthesis and the fragmentation patterns for 2‐(p‐acetylaminosulfonamido)‐2‐thiono‐(5,5‐dimethyl‐1,3,2‐dioxaphosphorinane)(1) and for the p‐acetylaminosulfonylamides of O,O‐diethylthiophosphoric acid (2), O,O‐diphenylthiophosphoric acid (3), dimethylaminocyclohexylthiophosphoric acid (4), and diethylaminophenylthiophosphoric acid (5). A thionamidic‐thiolimidic structure was attributed to compounds 1–5, consistent with their IR and NMR spectra. EI mass spectra at 70 eV, high resolution (HR) mass measurements and metastable ion spectra were used to elucidate the fragmentation processes and to determine the kinetic energy release values associated with the metastable ion dissociations. HR accurate mass measurements were used to confirm the compositions of the more abundant ions. Copyright © 2001 John Wiley & Sons, Ltd.
Deuterium/hydrogen isotope ratio measurement of water and organic samples by continuous‐flow isotope ratio mass spectrometry using chromium as the reducing agent in an elemental analyser
Authors: Kelly Simon D. , Heaton Karl D. , Brereton Paul
Published: September 2002

A rapid continuous‐flow technique for quantitative determination of hydrogen isotope ratios in water and organic materials at natural abundance levels is described. Water and organic samples were reduced in a helium stream at temperatures in excess of 1000 °C over chromium metal. δ2H‰ values of water and organic samples were determined by calibration against International Atomic Energy Agency reference materials V‐SMOW and SLAP water. The accuracy of the method was demonstrated through the analysis of the intermediate water standard GISP and IAEA water intercomparison materials OH‐1, OH‐2 and OH‐3. Values obtained using this technique compared well with reference values (maximum difference 2.2‰). The precision of water analyses was less than 2.3‰ (1 σ or 1 standard deviation) in all cases. No apparent memory effect was observed when measuring samples at the natural abundance level. The application of the technique to organic molecules and the salts of organic acids was successfully demonstrated by measuring the δ2H‰ values of an n‐hexadecane laboratory reference and anhydrous calcium formate versus water calibration materials. © Crown copyright 2001. Reproduced with permission of the Controller of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Use of a novel nitrification inhibitor to reduce nitrous oxide emission from 15N‐labelled dairy slurry injected into soil
Authors: Dittert Klaus , Bol Roland , King Rosalind , Chadwick David , Hatch David
Published: September 2002

Recent recommendations for environmentally sound use of liquid animal manure often include injection of slurry into soil. Two of the most important undesired side effects, ammonia (NH3) volatilisation and odour emissions, are usually significantly reduced by slurry injection. On the other hand, because of the higher amount of nitrogen (N) remaining in soil, the risk of nitrate (NO3−) leaching and nitrous oxide (N2O) emissions is increased. Thus, the reduction of local effects caused by NH3 deposition, e.g. N enrichment and soil acidification, may be at the cost of large‐scale effects such as ozone depletion and global warming as a result of emitted N2O. In this context, nitrification inhibitors can contribute significantly to a reduction in NO3− leaching and N2O production.

A field experiment was carried out at IGER, North Wyke, which aimed to evaluate the effect of the new nitrification inhibitor 3,4‐dimethylpyrazole phosphate (DMPP/ENTEC™). For this experiment, 15N enriched dairy slurry was used and the isotopic label in soil N as well as in N2O were studied. After slurry injection into the grassland soil in August 2000, the major emissions of N2O occurred during the first ten days. As expected, high N2O emission rates and 15N content of the emissions were concentrated on the slurry injection slots, showing a steep decrease towards the untreated centre‐point between slurry injection slots. The nitrification inhibitor DMPP proved to be very efficient in reducing N2O emissions. At a rate of 2 kg DMPP ha−1, the total amount of N2O emitted was reduced by 32%, when compared with slurry injection without DMPP. The isotopic label of the emitted N2O showed that during the 22‐day experimental period, emissions from the slurry N pool were strongly reduced by DMPP from 0.93 kg N2O‐N ha−1 (−DMPP) to 0.50 kg N2O‐N ha−1 (+DMPP), while only a minor effect on emissions from the soil N pool was observed (0.69 to 0.60 kg N2O‐N ha−1; −DMPP, +DMPP, respectively). Copyright © 2001 John Wiley & Sons, Ltd.
Development of δ15N stratification of NO3− in soil profiles
Authors: Handley Linda L. , Johnston Andrew M. , Hallett Paul D. , Scrimgeour Charles M. , Wheatley Ronald E.
Published: September 2002

New evidence, obtained using a robust method for measuring the δ15N of NO3−‐N in soil, is consistent with denitrification being the major determinant in the vertical distribution of NO3−‐δ15N in soil profiles. These data also suggest that varying moisture regimes result in different effects of soil NO3−‐N leaching on residual whole soil δ15N. Copyright © 2001 John Wiley & Sons, Ltd.
Strategic environmental assessment for sustainable households in 2050: illustrated for clothing
Authors: Bras‐Klapwijk Remke M. , Knot J. Marjolijn C.
Published: September 2002

This paper discusses the environmental assessment approach that has been developed and applied in the SusHouse project (Strategies towards the Sustainable Household). This project aims at developing and evaluating strategies for a sustainable development of households in the future, for three basic household activities: nutrition, shelter and clothing. The environmental assessment approach in the SusHouse project is different from traditional approaches such as life cycle assessment, due to the system‐level character and due to the focus on future developments. Examples are taken from the clothing research in the Netherlands. Copyright © 2001 John Wiley & Sons, Ltd and ERP Environment.
Nanohardness measurement of carbon nitride thin films
Authors: Kojima Isao , Xu Wentao , Fujimoto Toshiyuki
Published: September 2002

A nanohardness measurement method using an atomic force microscope equipped with a diamond tip is described and applied to carbon nitride thin films. These films were prepared by radiofrequency magnetron sputtering at various substrate temperatures. Based on the general hardness definition, the hardness of thin films was determined directly from the indentation force and the (residual) indentation depth using fused silica as a standard reference. The hardnesses measured by this technique are quite reproducible. The hardnesses of the carbon nitride thin films with a thickness of ∼35 nm were in the range 31–35 GPa, increasing slightly with substrate temperature. This increase is in good correlation with the film density changes as measured by grazing‐incidence x‐ray reflectivity. Copyright © 2001 John Wiley & Sons, Ltd.
XRD and XPS studies on the ultra‐uniform Raney‐Ni catalyst prepared from the melt‐quenching alloy
Authors: Lei Hao , Song Zhen , Bao Xinhe , Mu Xuhong , Zong Baoning , Min Enze
Published: September 2002

We present a novel method for preparing an ultra‐uniform Raney‐Ni catalyst, which includes melt‐quenching, hydrogen treatment and leaching in an alkali solution. The resultant catalyst shows superior activity in the reaction of cyclohexanone hydrogenation. X‐ray diffraction (XRD) and XPS have been employed to characterize the catalysts. As demonstrated, the pretreatment with hydrogen caused a distinct phase transfer of the Ni–Al alloys, forming more of the Ni2Al3 component. In the subsequent leaching process, the Ni2Al3 component shows high activity and the resultant catalyst exhibits high surface areas and small pores. Moreover, metallic Al in the hydrogen‐pretreated alloy appeared to be leached more easily and thus the aluminium species remaining on the catalyst surface is aluminium oxide predominantly, which serves as a matrix to stabilize active Ni species on the surface. Copyright © 2001 John Wiley & Sons, Ltd.
Study of the diffusion behaviour of MoO3and ZnO on oxide thin films by SR‐TXRF
Authors: Xu Weiming , Xu Junqian , Wu Nianzu , Yan Jingfeng , Zhu Yongfa , Huang Yuying , He Wei , Xie Youchang
Published: September 2002

The diffusion process of MoO3and ZnO on stable oxide thin films (SiO2, Al2O3, TiO2) was investigated mainly by means of synchrotron‐radiation‐excited total reflection x‐ray fluorescence spectroscopy (SR‐TXRF). A stripe of MoO3or ZnO on the oxide thin film was used as the diffusion source. After thermal treatment, MoO3diffused onto the surface of those films and formed a monolayer or a submonolayer. The diffusion capacity and the diffusion rate of MoO3on each film differed significantly. Sublimation of MoO3also was detected during the diffusion process. A possible explanation for all the phenomena is the combination of surface diffusion onto the surface of the support and transportation via the gas phase. By contrast, ZnO hardly diffuses onto the surface of the film due to its high melting point. Copyright © 2001 John Wiley & Sons, Ltd.
What's in a name.com?: The effects of ‘.com’ name changes on stock prices and trading activity
Authors: Lee Peggy M.
Published: September 2002

This paper uses a market signaling perspective to examine investor reactions to firm announcements of name changes to include ‘.com.’ Firms that change their name as a purely cosmetic technique are contrasted to those that employ other strategic investments. Results show that announcements of ‘.com’ name changes are associated with significant increases in stock prices and trading activity. Furthermore, the magnitude of investor reactions is significantly larger when name changes are accompanied by other strategies. Copyright © 2001 John Wiley & Sons, Ltd.
Investing in the renewal of urban science teaching
Authors: Knapp Michael S. , Plecki Margaret L.
Published: September 2002

This article provides a conceptual framework for understanding what is involved in improving urban science teaching and what might be implied by conducting research on its improvement. It is argued in this article that three sets of forces and conditions have a direct impact on urban science classrooms: first, the array of interdependent policies at school, district, and state levels about science teaching in particular and about education improvement more broadly construed; next, the investment and use of instructionally relevant resources at each of the three levels and their differing impacts on the renewal of urban science teaching; and finally, the broader context in which urban science teaching occurs mediating how these resources are—or can be—used. Mediating factors include the professional peer community, subject‐specific instructional leadership, the professional development infrastructure, the supply of available science teachers, and the broader community context. The article concludes with suggestions for how this framework informs directions for future research on the promise and limits of efforts to renew science teaching in urban settings. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 1089–1100, 2001
Septo‐optic dysplasia as a manifestation of valproic acid embryopathy
Authors: McMahon Carrie L. , Braddock Stephen R.
Published: September 2002

Background

The use of valproic acid during pregnancy has been associated with adverse fetal outcomes, including major and minor congenital malformations, intrauterine growth retardation (IUGR), hyperbilirubinemia, hepatotoxicity, transient hyperglycemia, and fetal and neonatal distress. In addition, intrauterine exposure to valproic acid has been associated with an increased risk of central nervous system abnormalities, primarily neural tube defects. Optic nerve hypoplasia has been reported in association with other prenatal anticonvulsant exposures, but the occurrence of septo‐optic dysplasia as a manifestation of valproic acid embryopathy has not been reported previously.

Results

We report on a woman who received Depakote (valproic acid) throughout her pregnancy for the treatment of a seizure disorder. The patient presented with features typical of valproic acid embryopathy, including bitemporal narrowing, hypertelorism, short palpebral fissures, epicanthal folds, microphthalmia, a flat broad nasal bridge, small mouth, hypoplastic nails, mild clinodactyly, and camptodactyly. MRI showed hypoplasia of the optic chiasm and absence of the septum pellucidum.

Conclusions

We report the first case of septo‐optic dysplasia associated with maternal exposure to valproic acid throughout pregnancy. This case expands the clinical phenotype of valproate embryopathy. Teratology 64:83–86, 2001. © 2001 Wiley‐Liss, Inc.
Identification of Candida tropicalis HSR1, a gene of the heat‐shock factor‐related family, which confers salt tolerance in Saccharomyces cerevisiae
Authors: Ali Rashid , Pascual‐Ahuir Amparo , Marquez Jose A. , Malik Kauser A. , Serrano Ramon
Published: September 2002

A genomic library of Candida tropicalis in a yeast multicopy plasmid has been screened for clones conferring salt tolerance upon transformation into S. cerevisiae. The best halotolerance clone contained an open reading frame encoding a predicted protein of 728 amino acids with homology to transcription factors of the heat‐shock family. This novel gene was named HSR1 and is present in single copy in the C. tropicalis genome. Upon transformation into S. cerevisiae it increases the expression of ENA1, a major determinant of salt tolerance encoding a cation‐extrusion pump. The sequence of CtHSR1 has been deposited in the EMBL data library under Accession No. AJ296093. Copyright © 2001 John Wiley & Sons, Ltd.
Managing the socialization of an adult male gorilla (Gorilla gorilla gorilla) with a history of social deprivation
Authors: Burks Kyle D. , Bloomsmith Mollie A. , Forthman Debra L. , Maple Terry L.
Published: September 2002

Most non‐human primates exhibit aggression during changes in social group composition. In zoological parks, group membership changes are necessary for optimal population management, but can elicit problematic aggression. Furthermore, some primates with a long history of social deprivation are hyperaggressive when introduced to conspecifics. In this study of one male gorilla with a 30‐year history of social deprivation, we assessed the rate of aggression quantitatively during a four‐step socialization procedure. We hypothesized that 1) the frequency of agonistic/display behaviors would increase markedly at the beginning of each phase of the socialization, then decline to baseline levels over time in each phase and 2) the frequency of affiliative behaviors would not vary systematically within or between phases of socialization. Our results largely supported these predictions, and we found the four‐step socialization process effective in managing aggression in this case. In addition to documenting the successful socialization of a socially deprived adult male gorilla, we believe that the empirical process used in this case argues for scientific management of other introductions. Zoo Biol 20:347–358, 2001. © 2001 Wiley‐Liss, Inc.
The development and application of a method to quantify the quality of cryoprotectant solutions using standard area-detector X-ray images
Authors: McFerrin Michael B. , Snell Edward H.
Published: September 2002

An X-ray based method for determining initial cryoprotectant concentrations necessary to protect solutions from crystalline ice formation on flash cooling was developed. X-ray images from a charge-coupled device (CCD) area detector were integrated as powder patterns and quantified by determining the standard deviation of the slope of the normalized intensity curve in the resolution range where ice rings are known to occur. The method was tested by determining the concentrations of glycerol, PEG400, ethylene glycol and 1,2-propanediol necessary to form an amorphous glass at 100 K with each of the 98 crystallization solutions of Crystal Screens I and II (Hampton Research, Laguna Hills, California, USA). For conditions that required glycerol concentrations of 35% or above, cryoprotectant conditions using (2R,3R)-(−)-2,3-butanediol were determined. The method proved to be remarkably reliable. The results build on previous work [Garman & Mitchell (1996).J. Appl. Cryst.29, 584–587] and extend the number of suitable starting conditions to alternative cryoprotectants.
ZONES: a search/match database for single-crystal electron diffraction
Authors: Hart Haskell V.
Published: September 2002

ZONES is a relational database built from NIST Crystal Data for the identification of single crystals by selected area electron diffraction (SAED) and elemental analysis using MicrosoftAccess 97for the personal computer (subsequently converted toAccess 2000). The two largest experimentaldspacings and included angle in a zone are matched against values calculated from reduced unit cells, thereby fully and rigorously incorporating the effects of double diffraction. A total of 79136 inorganic phases are included with original Crystal Data reference codes, allowing access to all the information in NIST Crystal Data. Specific examples illustrate the robustness of this approach. This database will be most useful to researchers in mineralogy, metallurgy, materials science, forensics and analytical chemistry who seek to identify well characterized phases with known unit cells.
Contrast factors of dislocations in the hexagonal crystal system
Authors: Dragomir I. C. , Ungár T.
Published: September 2002

Strain anisotropy can be well accounted for by the dislocation model of lattice distortion. In a texture-free powder or polycrystal, or if all possible Burgers vectors are equally populated, the dislocation contrast factors are a linear function of the fourth-order invariants of thehklindices. Using this relation the dislocation contrast factors have been evaluated numerically and compiled for a number of common hexagonal materials. A procedure is presented to match experimentally determined contrast factor parameters with the numerically obtained parameter values. The procedure can be used as a tool to extract the microstructure from strain anisotropy in terms of Burgers vector populations, dislocation densities, crystallite size and size distributions in hexagonal crystals. Its practical use is illustrated by the application to plastically deformed titanium.
Quantitative phase analysis of strongly textured alloy mixtures using neutron diffraction
Authors: Shin E. J. , Seong B. S. , Lee C. H. , Huh M. Y.
Published: September 2002

Based on the Rietveld profile refinement of neutron diffraction patterns and a new texture analysis method, a quantitative phase analysis (QPA) method is proposed and examined in the case of artificially produced multiphase alloys having strong textures. The preferred-orientation factors (POFs) of the diffraction peaks were extracted from the inverse pole figure calculated from the orientation distribution function (ODF) that was computed from the averaged pole figures measured by the rotating sample stage, providing a faster and simpler texture measurement. The reliability of this method was examined using binary alloy mixtures of known fractions of zirconium and aluminium. In addition, the fraction of unknown phases in an artificially produced aluminium matrix composite was determined by introducing a standard zirconium sample. QPA of the binary mixtures successfully predicted the weight fraction of each component with an absolute error of less than 0.3 wt%. This method also provided appropriate results on the calculation of the weight fraction of unknown phases in the aluminium matrix composite.
The resolution function for a time-of-flight hybrid neutron spectrometer with crystal monochromator and chopper
Authors: Ionita I.
Published: September 2002

A procedure for computing the resolution function for a time-of-flight hybrid neutron spectrometer with crystal monochromator and chopper using the matrix computation technique is presented. A brief general description of the matrix computation technique and the computer programHYBR, implementing the matrix procedure, are also presented. Some ideal focusing conditions deduced by compensating the major contributions to the variances of the scan variable are given; these ideal conditions can be used as a zeroth-order approximation in a numerical optimization procedure.
X-ray scattering of non-graphitic carbon: an improved method of evaluation
Authors: Ruland Wilhelm , Smarsly Bernd
Published: September 2002

The wide-angle X-ray scattering (WAXS) of non-graphitic carbons shows relatively broad and diffuse interference maxima. In most cases, the corresponding line profiles cannot be separated unambiguously, so that an evaluation using profile analysis is difficult. In these cases, fitting procedures for the total scattering curve are more appropriate. This requires theoretical expressions for all interference maxima with a sufficient number of relevant structural parameters to ensure an acceptable fit. In this paper, such expressions are presented for the (hk) lines (intralayer scattering) and the (00l) lines (interlayer scattering), and the application of these expressions to the evaluation of selected WAXS curves is described. Furthermore, the effects of thermal motion, preferred orientation and Compton scattering are discussed.
COMPANG: automated comparison of orientations
Authors: Urzhumtseva Ludmila , Urzhumtsev Alexandre
Published: September 2002

A search for similar orientations of a three-dimensional object is a usual task in structure analysis. An example is a comparison of peaks of rotation functions in molecular replacement. An automated comparison of orientations defined as a list or several lists of corresponding Eulerian angles can be performed using the interactive programCOMPANG. When calculating the closeness of orientations, this program allows one to take into account the symmetry operations of the space group as well as non-crystallographic symmetry. The similarity of orientations can be considered at a given accuracy, thus allowing a user to identify the groups of close orientations,i.e.their clusters. The size of such clusters can be used as a criterion to choose the correct orientation in difficult cases of molecular replacement.
From test tube to plate: a simple procedure for the rapid preparation of microcrystallization experiments using the cubic phase method
Authors: Nollert Peter
Published: September 2002

Crystals of transmembrane proteins for X-ray diffraction experiments may be grown either by employing mixed protein–detergent complexes, or in a matrix of liquid-crystalline membraneous material forming a lipidic cubic phase (in cubo). Widespread use of thein cubomethod has been severely hampered by its tediousness and the large amounts of protein required. Here a simple procedure is presented that by virtue of its simplicity and small setup size substantially reduces the preparation time as well as the amount of protein. Crystallization trials are set up in conventional multi-well plates using a semi-automatic dispenser-driven microsyringe. The microprocedure is amenable to full automation and further miniaturization. Its feasibility is demonstrated by screening for new crystallization conditions for bacteriorhodopsin using volumes ofca200 nl of lipidic cubic phase. New crystallization conditions were identified that avoid the necessity of weighing solid precipitation agents.