bluuebunny/crossref_metadata_2025 huggingface dataset:
Biocompatibility of lipid‐protein‐sugar particles containing bupivacaine in the epineurium
Authors: Kohane Daniel S. , Lipp Michael , Kinney Ramsey C. , Anthony Douglas C. , Louis David N. , Lotan Noah , Langer Robert
Published: August 2002

Novel lipid‐protein‐sugar particles (LPSPs) are potentially biocompatible because they are composed of naturally occurring ingredients and their expected tissue dwell times are relatively short. In this research, we used histological sections to study tissue reaction to LPSPs (4.4‐μm median diameter) when used for sciatic nerve block in the rat. As a reference, we compared LPSPs to 60‐μm median diameter poly(lactic‐co‐glycolic) acid (PLGA) microspheres (110,000 MW PLGA, glycolic/lactic ratio 65:35). Four days after injection, both particle types produced acute inflammation within the confines of the injectate, inflammation in adjacent tissues, and myotoxicity. Bupivacaine‐free particles did not display myotoxicity, and inflammation in adjacent tissues was reduced. At 2 weeks, inflammation from LPSPs had almost disappeared, whereas PLGA microspheres had a foreign‐body giant cell reaction until at least 8 weeks after injection. In contrast, 3.6‐μm median diameter, 20,000‐MW PLGA microspheres produced a primarily histiocytic reaction 2 weeks after injection. In summary, the LPSPs and PLGA microspheres studied herein have excellent biocompatibility, but tissue reaction to the former is of much shorter duration. Myotoxicity and inflammation of surrounding tissue is largely attributed to bupivacaine. Foreign‐body giant cells may be attributed to particle size rather than a specific reaction to PLGA. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 450–459, 2002
Arsenite stimulates cyclooxygenase‐2 expression through activating IκB kinase and nuclear factor κB in primary and ECV304 endothelial cells
Authors: Tsai Shu‐Huei , Liang Yu‐Chih , Chen Linda , Ho Feng‐Ming , Hsieh Ming‐Shium , Lin Jen‐Kun
Published: August 2002

Epidemiological studies have shown that chronic exposure to arsenic can result in liver injury, peripheral neuropathy, arteriosclerosis, and an increased incidence of cancer of the lung, skin, bladder, and liver. The overexpression of inducible cyclooxygenase‐2 (Cox‐2) has been associated with vascular inflammation and cellular proliferation. However, the effect of arsenite on Cox‐2 gene expression in endothelial cells was left to be investigated. Western Blot analysis of HUVECs revealed a two‐fold induction of Cox‐2 protein by arsenite. This induction was associated with a two‐fold increase of prostaglandin E2 in the media. Furthermore, the level of Cox‐2 mRNA was correspondingly elevated as demonstrated by both Northern blot and reverse transcriptase‐polymerase chain reaction (RT‐PCR) analyses. Transfection of an immortalized human endothelium cell line (ECV304) with Cox‐2 reporter gene constructs demonstrated that the transcription of Cox‐2 gene was enhanced by arsenite. This induction was attenuated by pyrrolidine dithiocarbamate (PDTC), an inhibitor of NFκB. In addition, electrophoretic mobility shift assays indicated that NFκB activity was induced by arsenite. The kinase activity assay also indicated that IκB kinase (IKK) activity was induced by arsenite. These findings indicated that the induction of Cox‐2 gene transcription by arsenite was through the stimulation of NFκB activity. Arsenite could induce IKK activity, which leads to the phosphorylation and degradation of IκB in ECV304 cells. Therefore, it appears that IKK signaling pathway is involved in arsenite‐mediated Cox‐2 expression. J. Cell. Biochem. 84: 750–758, 2002. © 2002 Wiley‐Liss, Inc.
S111N mutation in the helical domain of human Gsα reduces its GDP/GTP exchange rate
Authors: Brito Mónica , Guzmán Leonardo , Romo Ximena , Soto Ximena , Hinrichs María Victoria , Olate Juan
Published: August 2002

G‐protein α subunits consist of two domains: a Ras‐like domain also called GTPase domain (GTPaseD), structurally homologous to monomeric G‐proteins, and a more divergent domain, unique to heterotrimeric G‐proteins, called helical domain (HD). G‐protein activation, requires the exchange of bound GDP for GTP, and since the guanine nucleotide is buried in a deep cleft between both domains, it has been postulated that activation may involve a conformational change that will allow the opening of this cleft. Therefore, it has been proposed, that interdomain interactions are playing an important role in regulating the nucleotide exchange rate of the α subunit. While constructing different Gsα quimeras, we identified a Gsα random mutant, which was very inefficient in stimulating adenylyl cyclase activity. The introduced mutation corresponded to the substitution of Ser111 for Asn (S111N), located in the carboxi terminal end of helix A of the HD, a region neither involved in AC interaction nor in the interdomain interface. In order to characterize this mutant, we expressed it in bacteria, purified it by niquel‐agarose chromatography, and studied its nucleotide exchange properties. We demonstrated that the recombinant S111N Gsα was functional since it was able to undergo the characteristic conformational change upon GTP binding, detected by the acquisition of a trypsin‐resistant conformation. When the biochemical properties were determined, the mutant protein exhibited a reduced GDP dissociation kinetics and as a consequence a slower GTPγS binding rate that was responsible for a diminished adenylyl cyclase activation when GTPγS was used as activator. These data provide new evidence that involves the HD as a regulator of Gsα function, in this case the αA helix, which is not directly involved with the nucleotide binding site nor the interdomain interface. J. Cell. Biochem. 85: 615–620, 2002. © 2002 Wiley‐Liss, Inc.
Molecular mechanics (MM4) calculations on carbonyl compounds part I: aldehydes
Authors: Langley Charles H. , Lii Jenn‐Huei , Allinger Norman L.
Published: August 2002

Aliphatic aldehydes have been studied with the aid of the MM4 force field. The structures, moments of inertia, vibrational spectra, conformational energies, barriers to internal rotation, and dipole moments have been examined for six compounds (nine conformations). MM4 parameters have been developed to fit the indicated quantities to the wide variety of experimental data. Ab initio (MP2) and density functional theory (B3LYP) calculations have been used to augment and/or replace experimental data, as appropriate. Because more, and to some extent, better, data have become available since MM3 was developed, it was anticipated that the overall accuracy of the information calculated with MM4 would be better than with MM3. The best single measure of the overall accuracy of a force field is the accuracy to which the moments of inertia of a set of compounds (from microwave spectroscopy) can be reproduced. For all of the 20 moments (seven conformations) experimentally known for the aldehyde compounds, the MM4 rms error is 0.30%, while with MM3, the most accurate force field presently available, the rms error over the same set is 1.01%. The calculation of the vibrational spectra was also improved overall. For the four aldehydes that were fully analyzed (over a total of 78 frequencies), the rms errors with MM4 and MM3 are 18 and 38 cm−1, respectively. These improvements came from several sources, but the major ones were separate parameters involving the carbonyl carbon for formaldehyde, the alkyl aldehydes and the ketones, and new crossterms featured in the MM4 force field that are not present in the MM3 version. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1396–1425, 2001
Fibronectin, integrins, and growth control
Authors: Danen Erik H.J. , Yamada Kenneth M.
Published: August 2002

Cell proliferation is controlled not only by soluble mitogens but also by components of the extracellular matrix (ECM) such as fibronectin, to which cells adhere via the integrin family of transmembrane receptors. Input from both growth factor receptors and integrins is required to stimulate progression through the G1 phase of the cell cycle, via induction of G1 cyclins and suppression of inhibitors of the G1 cyclin‐dependent kinases. Extensive crosstalk takes place between integrin and growth factor receptor signaling pathways, and mitogenic signaling is weak and transient in the absence of integrin‐mediated cell adhesion. In normal untransformed cells, all of the important mitogenic signal transduction cascades, namely those downstream of the Ras and Rho family small GTPases and the phosphoinositide 3‐OH kinase‐PKB/Akt pathway, are regulated by integrin‐mediated cell adhesion. As a result, these cells are anchorage‐dependent for growth. In contrast, constitutive activity of each of these pathways has been reported in cancer cells, which not only reduces their mitogen dependence but also allows these cells to grow in an anchorage‐independent fashion. © 2001 Wiley‐Liss, Inc.
ICTs, gender and development: women in software production in Kerala
Authors: Arun Shoba , Arun Thankom
Published: August 2002

The impact of information and communication technologies (ICTs) on development largely depends on the existing economic, social and cultural fabric into which they are introduced. This can be seen in the case of Kerala in India, which has been implementing an ICT‐based strategy that particularly seeks to create growth and employment through software production. A gendered perspective on software production shows that ICTs create opportunities for women. However, they also reproduce gender inequalities seen in the broader fabric of society. ICT policies must therefore take account of the gendered roles, norms and practices that affect both labour markets and households because these, in turn, affect both the outcome and sustainability of ICT‐based development. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis of [4‐11C]amino acids via ring‐opening of aziridine‐2‐carboxylates
Authors: Gillings N. M. , Gee A. D.
Published: August 2002

Ring‐opening of N‐(tert‐butoxycarbonyl)aziridine‐2‐isopropyl carboxylate with no‐carrier‐added (n.c.a.) [11C]cyanide is reported. Following purification by HPLC, the protected D,L‐[4‐11C]β‐cyanoalanine was subsequently hydrolysed, to yield D,L‐[4‐11C]asparagine or D,L‐[4‐11C]aspartic acid, or reduced followed by hydrolysis to give D,L‐2,4‐diamino[4‐11C]butyric acid. Typical syntheses starting with 10 GBq hydrogen [11C]cyanide yielded 1–1.4 GBq of [4‐11C]amino acid within 30 min, giving the labelled amino acids in 30–40% decay corrected radiochemical yield (counted from [11C]cyanide) with radiochemical purities of 95%, 98% and 60%, respectively. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis and characterization of [vinylidene‐3H] (−)‐α‐kainic acid at high specific activity
Authors: Ahern David G. , Seguin Richard J. , Filer Crist N.
Published: August 2002

[Vinylidene‐3H] (−)‐α‐Kainic acid was prepared by means of a Wittig reaction with a protected ketone precursor and has proved useful as a tool to study neuroexcitatory amino acid receptors. Copyright © 2002 John Wiley & Sons, Ltd.
MRI in lung transplant recipients using hyperpolarized 3He: Comparison with CT
Authors: Gast Klaus K. , Viallon Magali , Eberle Balthasar , Lill Jana , Puderbach Michael U. , Hanke Alexander T. , Schmiedeskamp Joerg , Kauczor Hans‐Ulrich
Published: August 2002

Purpose

To elucidate the ability of 3He‐MRI to detect ventilation defects in lung transplant recipients, 3He‐MRI was compared to CT for concordance.

Materials and Methods

We examined 14 lung recipients using 3He‐MRI on a 1.5 T MR scanner. CT served as a reference method. Up to four representative ventilation defects were defined for each lung on 3He‐MRI and compared to corresponding areas on CT.

Results

Altogether, 59 representative ventilation defects were defined on 3He‐MRI. Plausible CT correlates were found for 29 ventilation defects; less plausible CT correlates were found for eight defects. In 22 defects (37%) no corresponding CT changes were detected. CT demonstrated correlates for ventilation defects seen on 3He‐MRI in only 63% of the cases.

Conclusion

3He‐MRI yields a clear increase in the number of detected ventilation defects compared to CT. This may have an important impact on the early detection of bronchiolitis obliterans in lung transplant recipients. J. Magn. Reson. Imaging 2002;15:268–274. © 2002 Wiley‐Liss, Inc.
Respiratory motion in coronary magnetic resonance angiography: A comparison of different motion models
Authors: Manke Dirk , Nehrke Kay , Börnert Peter , Rösch Peter , Dössel Olaf
Published: August 2002

Purpose

To assess respiratory motion models for coronary magnetic resonance angiography (CMRA). In this study various motion models that describe the respiration‐induced 3D displacements and deformations of the main coronary arteries were compared.

Materials and Methods

Multiple high‐resolution 3D coronary MR images were acquired in healthy volunteers using navigator‐based respiratory gating, each depicting the coronary vessels at different respiratory motion states. In the images representing the different inspiratory states the displacements and deformations of the main coronary vessels with respect to the end‐expiratory state were determined, by means of elastic registration. Several correction models (superior‐inferior (SI) translation, 3D translation, and 3D affine transformation) were tested and compared with respect to their ability to map a selected inspiratory to the end‐expiratory motion state.

Results

3D translation was found to be superior over SI translation, which is commonly used for prospective motion correction in CMRA. The 3D affine transformation was found to be the best correction model considered in this study. Furthermore, a large intersubject variability of the model parameters was observed.

Conclusion

The results of this study indicate that a patient‐adapted 3D correction model (3D translation or better 3D affine) will considerably improve prospective motion correction in CMRA. J. Magn. Reson. Imaging 2002;15:661–671. © 2002 Wiley‐Liss, Inc.
Real‐time black‐blood MRI using spatial presaturation
Authors: Nayak Krishna S. , Rivas Pedro A. , Pauly John M. , Scott Greig C. , Kerr Adam B. , Hu Bob S. , Nishimura Dwight G.
Published: August 2002

A real‐time interactive black‐blood imaging system is described. Rapid blood suppression is achieved by exciting and dephasing slabs outside the imaging slice before each imaging excitation. Sharp‐profiled radio frequency saturation pulses placed close to the imaging slice provide good blood suppression, even in views containing slow through‐plane flow. In vivo results indicate that this technique improves endocardial border definition during systole in real‐time cardiac wall‐motion studies. Phantom and animal results indicate that this technique nearly eliminates flow artifacts in real‐time intravascular studies. J. Magn. Reson. Imaging 2001;13:807–812. © 2001 Wiley‐Liss, Inc.
Intensity dependence of cation kinetic energies from 2,5‐dihydroxybenzoic acid near the infrared matrix‐assisted laser desorption/ionization threshold
Authors: Ermer D. R. , Baltz‐Knorr M. , Haglund R. F.
Published: August 2002

The mechanisms responsible for matrix‐assisted laser desorption/ionization (MALDI) are far from being well understood, particularly where infrared laser irradiation is used to initiate the process. We measured the emission yields and kinetic energy distributions of positive ions emitted from 2,5‐dihydroxybenzoic acid loaded with angiotensin II in a standard MALDI preparation during irradiation with an infrared free‐electron laser tuned to 2.94 µm. As the laser intensity is scanned through the MALDI threshold, we see a marked change in the energy distributions of the matrix ion. Above threshold, the energy distributions of both analyte and matrix cations are constant over a broad range of laser intensities. This behavior does not appear to be consistent with any extant model of the MALDI mechanism. Copyright © 2001 John Wiley & Sons, Ltd.
Involvement of TLCK‐sensitive serine protease in colchicine‐induced cell death of sympathetic neurons in culture
Authors: Mitsui Chizu , Sakai Kazuhisa , Ninomiya Takafumi , Koike Tatsuro
Published: August 2002

Superior cervical ganglion (SCG) cells from neonatal rats underwent apoptosis upon treatment with colchicine, a microtubule‐disrupting agent. Western blotting and activity measurements showed that caspase‐3 was indeed activated, but its peptide inhibitor (Ac‐DEVD‐CHO) neither suppressed nuclear fragmentation nor rescued the neurons from cell death. z‐VAD‐fmk, the general inhibitor of caspases, prevented nuclear fragmentation and delayed the cell death. Moreover, N‐α‐tosyl‐L‐lysine chloromethyl ketone (TLCK), but not N‐α‐tosyl‐L‐phenylalanine chloromethyl ketone (TPCK), prevented nuclear fragmentation and provided neuronal protection as well. The combination of both z‐VAD‐fmk and TLCK provided a long‐term neuronal protection (>4 days), whereas neither one alone could do so, suggesting that there are both caspase‐dependent and ‐independent pathways. TLCK‐sensitive serine protease is also likely to act upstream of caspase‐3 in a caspase‐dependent pathway. Electron microscopic observations demonstrated that z‐VAD‐fmk suppressed nuclear fragmentation and improved mitochondrial swelling, but failed to prevent vesicular formation, which resulted in a slowly‐occurring necrosis. More importantly, TLCK effectively blocked this abundant vesicular formation along with suppressing chromatin condensation. Thus, the combination of both conferred a nearly normal morphology, which is consistent with the results of cell survival experiments. These findings clearly indicate that TLCK‐sensitive serine protease plays multiple roles in caspase‐dependent and ‐independent pathways of colchicine‐induced cell death, and suggest a novel mechanism underlying a necrotic pathway involving ER swelling and vesicular formation. J. Neurosci. Res. 66:601–611, 2001. © 2001 Wiley‐Liss, Inc.
Resonance Raman spectrum of [Ru(bipyridine)3]2+ in water, acetonitrile and their deuterated derivatives: the possible role of solvent in excited‐state charge localization
Authors: Adam Webb M. , Knorr Fritz J. , McHale Jeanne L.
Published: August 2002

Resonance Raman spectra excited at 458 and 476 nm are reported for [Ru(bipyridine)3]2+ in water, acetonitrile and their perdeuterated derivatives. Raman intensities of [Ru(bipyridine)3]2+ are about a factor of two greater in H2O than D2O for all vibrational modes, but are independent of solvent isotopomer in acetonitrile. Solvent dynamics apparently contribute more strongly to the dephasing dynamics in water than in acetonitrile. Mode‐specific dephasing rates seem to cause different depolarization ratios for different observed vibrations which can lead to a potentially misleading interpretation of the depolarization ratios. We speculate that a static complex between [Ru(bipyridine)3]2+ and water influences the excited‐state dynamics. Copyright © 2001 John Wiley & Sons, Ltd.
Pressure dependence of photoluminescence of ZnTe/Zn1−xCdxTe strained‐layer superlattice
Authors: Li W. S. , Shen Z. X. , Li H. Y. , Shen D. Z. , Fan X. W.
Published: August 2002

Photoluminescence (PL) spectra of ZnTe/Zn1−xCdxTe (x = 0.23) strained‐layer superlattice (SLS) samples were studied at hydrostatic pressures up to 4.8 GPa at room temperature. A sublinear pressure dependence of the PL peaks for both the heavy‐hole exciton and the donor–acceptor pair was observed. The first‐ and second‐order pressure coefficients of the PL peaks were obtained by a least‐squares fit. An analytical expression for the heavy‐hole exciton was also derived. The pressure coefficients obtained from the analytical expression are 104 meV GPa−1 and −4.44 meV GPa−2, in excellent agreement with the experimental values of 103.9 meV GPa−1 and −4.5 meV GPa−2. It is shown that the contribution to the linear pressure coefficient comes exclusively from the hydrostatic component. Both hydrostatic and biaxial terms are responsible for the second‐order pressure coefficient, with a negative contribution of −6.07 meV GPa−2 and a positive contribution of 1.63 meV GPa−2, respectively. Copyright © 2001 John Wiley & Sons, Ltd.
Structure and Raman spectra of NdxY1−xBa2Cu3O7−δ
Authors: Hiep Duong Cong , Lam Vu Dinh , Hong Le Van
Published: August 2002

NdxY1−xBa2Cu3O7−δ superconductor samples were prepared by the solid‐state reaction method. Yttrium was partially substituted by Nd with a content ranging from 0 to 100%. The phase purity of the given samples was checked by x‐ray diffraction, which showed that the samples are of the pure superconducting phase. The phase transition temperatures Tc of all the samples were estimated from the temperature dependence of their resistance measured by the four‐probe technique. Tc decreases slightly with increasing neodymium concentration substituted for yttrium. The Raman backscattering spectra were recorded at room temperature in the two polarization configurations z(x′,x′) − z and x′(z,z) − x′. The results show that the Raman shifts of the vibrational modes of the oxygen O4 and of the couple O2–O3 are affected by an internal pressure effect due to the substitution for yttrium by neodymium, which has a larger ion radius. Nd substitution also affects the crystalline structure and leads to disorder of the copper chain layers, which is the main reason for the appearance of Raman lines related to the vibration modes of Cu1 and O1 in the copper chain layer. Copyright © 2001 John Wiley & Sons, Ltd.
Product levels as an aid to functional strategy development
Authors: Connor Tom
Published: August 2002

It is argued that practising managers benefit from conceptual frameworks to provide techniques for implementing business strategies. This paper:

Considers the link between the concept of strategy levels and the marketing concept of product levels,

Stresses that the success of business strategy is necessarily dependent upon effective implementation by the functional activities of the business,

Proposes a technique based on the product level concept for approaching the practical issues of strategy implementation at the functional level,

Suggests a greater emphasis by researchers on the practical problems of strategy implementation.

Copyright © 2001 John Wiley & Sons, Ltd.
Lutein in patients with cataracts and age‐related macular degeneration: a long‐term supplementation study
Authors: Olmedilla B , Granado F , Blanco I , Vaquero M , Cajigal C
Published: August 2002

Lutein, a non‐provitamin A xanthophyll, is widely distributed in fruits and vegetables frequently consumed. In human serum, lutein is transported by lipoproteins and selectively accumulated in certain tissues (eg the retina). Epidemiological studies suggest that high intake and serum levels of lutein are associated with a lower risk of cataracts and age‐related maculopathy. Subjects diagnosed with cataracts (CA; n  = 5) or age‐related macular degeneration (ARMD; n  = 5) agreed to take three lutein capsules per week. Each capsule potentially provided about 12 mg of all‐trans‐lutein, 3 mg of 13/15‐cis‐lutein and 3.3 mg of α‐tocopherol, as revealed by HPLC. Zeaxanthin was not detected. Average supplementation time was 13 months (range 4–20 months) for ARMD subjects and 26 months (range 16–36 months) for CA subjects. Blood samples for carotenoid analysis were collected every 3 months, coinciding with ophthalmological revision. In serum, concentrations of lutein, 13‐cis‐lutein and two ketocarotenoids increased significantly. Maximum increments were observed at 3–6 months, reaching levels above the 95th percentile of the reference population (>0.44 µmol l−1). Ophthalmological evaluation showed an average increment in visual acuity of 0.4, and glare sensitivity also improved. No significant side effects such as hypercarotenemia, carotenodermia or changes in biochemical or haematological profile were observed. Thus, lutein supplementation at achievable dietary levels increased and maintained serum lutein levels, which were associated with an improvement in the visual function of the patients.

© 2001 Society of Chemical Industry
Steric factors in the gas phase elimination kinetics of ethyl N‐benzyl‐N‐cyclopropylcarbamate and ethyl diphenylcarbamate
Authors: Luiggi Marniev , Dominguez Rosa M. , Rotinov Alexandra , Herize Armando , Cordova Mary , Chuchani Gabriel
Published: August 2002

The elimination kinetics of ethyl N‐benzyl‐N‐cyclopropylcarbamate and ethyl diphenylcarbamate were investigated over the temperature range of 349.9–440.0°C and the pressure range of 31–106 Torr. These reactions have been found to be homogeneous, unimolecular, and obey a first‐order rate law. The products are ethylene, carbon monoxide, and the corresponding secondary amine. The rate coefficient is expressed by the following Arrhenius equations:

For ethyl N‐benzyl‐N‐cyclopropylcarbamate

log k1 (s−1) = (12.94 ± 0.09) − (198.5 ± 0.9) kJ mol−1 (2.303RT)−1

For ethyl diphenylcarbamate

log k1 (s−1) = (12.91 ± 0.18) − (208.2 ± 2.4) kJ mol−1 (2.303RT)−1

The presence of phenyl and bulky groups at the nitrogen atom of the ethylcarbamate showed a decrease in the rate of elimination. Steric factor may be operating during the process of decomposition of these substrates. These reactions appear to undergo a semipolar six‐membered cyclic transition type of mechanism.© 2001 John Wiley & Sons, Inc. Int J Chem Kinet 34: 67–71, 2002
The fate of the hydroxyalkoxy radical in the OH‐initiated oxidation of isoprene
Authors: Reitz June E. , McGivern W. Sean , Church M. Clark , Wilson Marc D. , North Simon W.
Published: August 2002

Rate constants for several intermediate steps in the OH‐initiated oxidation of isoprene were determined using laser‐photolysis/laser‐induced fluorescence of OH radicals at total pressures between 3 and 4 Torr at 295 K. The rate constant for decomposition of the hydroxyalkoxy radical was determined to be (3.0 ± 0.5) × 104 s−1 in this pressure range, which is in fair agreement with previous work. The presence of a prompt alkoxy decomposition pathway was also investigated and found to contribute less than 10% to the total hydroxyalkoxy radical decomposition. The rate constant for the reaction of the hydroxyperoxy radical with NO was determined to be (2.5 ± 0.5) × 10−11 cm3 molecule−1 s−1, which is moderately higher than previously reported. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 255–261, 2002
Kinetics and mechanism of the reaction of OH with ClO
Authors: Bedjanian Yuri , Riffault Véronique , Bras Georges Le
Published: August 2002

The kinetics and mechanism of the following reactions have been studied in the temperature range 230–360 K and at total pressure of 1 Torr of helium, using the discharge‐flow mass spectrometric method: 1a:

1b:

The following Arrhenius expression for the total rate constant was obtained from the kinetics of OH consumption in excess of ClO radical, produced in the Cl + O3 reaction either in excess of Cl atoms or ozone: k1 = (6.7 ± 1.8) × 10−12 exp {(360 ± 90)/T} cm3 molecule−1 s−1 (with k1 = (2.2 ± 0.4) × 10−11 cm3 molecule−1 s−1 at T = 298 K), where uncertainties represent 95% confidence limits and include estimated systematic errors. The value of k1 is compared with those from previous studies and current recommendations. HCl was detected as a minor product of reaction (1) and the rate constant for the channel forming HCl (reaction (1b)) has been determined from the kinetics of HCl formation at T = 230–320 K: k1b = (9.7 ± 4.1) × 10−14 exp{(600 ± 120)/T} cm3 molecule−1 s−1 (with k1b = (7.3 ± 2.2) × 10−13 cm3 molecule−1 s−1 and k1b/k1 = 0.035 ± 0.010 at T = 298 K), where uncertainties represent 95% confidence limits. In addition, the measured kinetic data were used to derive the enthalpy of formation of HO2 radicals: Δ Hf,298(HO2) = 3.0 ± 0.4 kcal mol−1. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 587–599, 2001
Cross‐group comparisons: A cautionary note
Authors: Yoo Boonghee
Published: August 2002

This article alerts researchers to the importance of factorial invariance in comparative studies. Cross‐group or cross‐national comparisons, without a clear understanding of factorial structures, can result in misleading conclusions regarding compared groups. The types and process of invariance test are discussed. Then, as an empirical illustration, American consumer ethnocentrism toward Japanese products is examined across gender and age. © 2002 Wiley Periodicals, Inc.
Randomized comparison of cefepime versus ceftazidime monotherapy for fever and neutropenia in children with solid tumors*
Authors: Kebudi Rejin , Görgün Ömer , Ayan İnci , Gürler Nezahat , Akici Ferhan , Töreci Kurtuluş
Published: August 2002

Background

With the availability of new broad‐spectrum antibiotics, initial therapy with a single agent has become an alternative to classic combinations, especially β‐lactam antibiotics plus aminoglycosides, in the management of febrile neutropenic cancer patients.

Procedure

Since January 1994, monotherapy has been used for empiric initial treatment at our center. The aim of this prospective randomized study is to compare the efficacy of cefepime (CFP), a new fourth‐generation cephalosporin, and ceftazidime (CFZ) as empirical monotherapy of febrile neutropenic patients with solid tumors. From January 1998 to November 1998, 63 episodes of fever and neutropenia occurring in 33 children with solid tumors including lymphomas, were randomized to receive treatment with either CFP or CFZ. The patients were analyzed for leukocyte count and absolute neutrophil count (ANC) at entry, days in fever, neutropenia and hospitalization, and side effects of drugs. Success with or without modifications of the initial antibiotic was defined as survival through neutropenia; failure was death due to infection.

Results

In our study group, with a median age of 7 [(1/12)–14] years, CFP was administered in 32, and CFZ in 31 episodes. An infection was documented microbiologically in eight episodes (25%) in the CFP arm and in nine episodes (29%) in the CFZ arm. The success rate with initial empiric monotherapy was 62.5% in the CFP arm and 61.3% in the CFZ arm respectively (P > 0.05). The total success rate (success with or without modification) was 100% in both arms. No major adverse effects were observed in either groups.

Conclusions

CFP is as effective and safe as CFZ for the empirical treatment of febrile episodes in neutropenic patients with solid tumors. Med. Pediatr. Oncol. 36:434–441, 2001. © 2001 Wiley‐Liss, Inc.
Subvoxel processing: A method for reducing partial volume blurring with application to in vivo MR images of trabecular bone
Authors: Hwang Scott N. , Wehrli Felix W.
Published: August 2002

Partial volume blurring precludes accurate measurement of structural dimensions in the limited‐resolution regime in which image voxel size is larger than the typical structural element to be resolved. Since acquiring images at increased resolution often exacts an unacceptable signal‐to‐noise ratio (SNR) penalty, methods to alleviate the adverse effects of partial volume blurring are instrumental for the accurate measurement of architectural parameters in applications such as predicting the mechanical competence of trabecular bone networks. In the current work, a novel post‐processing method, referred to as “subvoxel processing,” is described for increasing apparent image resolution. The method is applicable to volumes of interest containing material phases of two discrete signal intensities. The principal strategy consists of subdividing voxels and assigning voxel intensities to each subvoxel on the basis of local neighborhood criteria and strict mass conservation. In the current work, the method's accuracy has been evaluated using microcomputed tomography images (22 × 22 × 22 μm3 voxel size) of human trabecular bone. The results demonstrate that subvoxel processing is significantly more accurate than trilinear interpolation in decreasing apparent voxel size, especially in the presence of noise. In addition, the method's effectiveness is illustrated with MR images of human trabecular bone acquired in vivo at 137 × 137 × 350 μm3 voxel size. The subvoxel‐processed images are shown to have architectural features characteristic of images acquired at higher spatial resolution. Magn Reson Med 47:948–957, 2002. © 2002 Wiley‐Liss, Inc.
Spiral‐in/out BOLD fMRI for increased SNR and reduced susceptibility artifacts
Authors: Glover Gary H. , Law Christine S.
Published: August 2002

BOLD fMRI is hampered by dropout of signal in the orbitofrontal and parietal brain regions due to magnetic field gradients near air‐tissue interfaces. This work reports the use of spiral‐in trajectories that begin at the edge of k‐space and end at the origin, and spiral in/out trajectories in which a spiral‐in readout is followed by a conventional spiral‐out trajectory. The spiral‐in trajectory reduces the dropout and increases the BOLD contrast. The spiral‐in and spiral‐out images can be combined in several ways to simultaneously achieve increased signal‐to‐noise ratio (SNR) and reduced dropout artifacts. Activation experiments employing an olfaction task demonstrate significantly increased activation volumes due to reduced dropout, and overall increased SNR in all regions. Magn Reson Med 46:515–522, 2001. © 2001 Wiley‐Liss, Inc.
Dynamic spiral MRI of pulmonary gas flow using hyperpolarized 3He: Preliminary studies in healthy and diseased lungs
Authors: Salerno Michael , Altes Talissa A. , Brookeman James R. , de Lange Eduard E. , Mugler John P.
Published: August 2002

An optimized interleaved‐spiral pulse sequence, providing high spatial and temporal resolution, was developed for dynamic imaging of pulmonary ventilation with hyperpolarized 3He, and tested in healthy volunteers and patients with lung disease. Off‐resonance artifacts were minimized by using a short data‐sampling period per interleaf, and gradient‐fidelity errors were compensated for by using measured k‐space trajectories for image reconstruction. A nonsequential acquisition order was implemented to improve image quality during periods of rapid signal change, such as early inspiration. Using a sliding‐window reconstruction, cine‐movies with a frame rate of 100 images per second were generated. Dynamic images demonstrating minimal susceptibility‐ and motion‐induced artifacts were obtained in sagittal, coronal, and axial orientations. The pulse sequence had the flexibility to image multiple slices almost simultaneously. Our initial experience in healthy volunteers and subjects with lung pathology demonstrated the potential of this new tool for capturing the features of lung gas‐flow dynamics. Magn Reson Med 4:667–677, 2001. © 2001 Wiley‐Liss, Inc.
Safe distances
Authors: David Israel
Published: August 2002

This work highlights the problem in military operations of setting safety limits for friendly forces, neutral forces, or civilians, to avoid sustaining unnecessary casualties both in wartime and in training. We present and investigate an analytic model which both enables the quantitative understanding of the inherent problems, and which furnishes a reasonably flexible tool in the hands of the analyst. Characteristic numerical results are displayed and analyzed: They show in particular that prevailing crude approximations are inadequate. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 259–269, 2001
Numerical methods for fourth‐order nonlinear elliptic boundary value problems
Authors: Pao C. V.
Published: August 2002

The aim of this article is to present several computational algorithms for numerical solutions of a nonlinear finite difference system that represents a finite difference approximation of a class of fourth‐order elliptic boundary value problems. The numerical algorithms are based on the method of upper and lower solutions and its associated monotone iterations. Three linear monotone iterative schemes are given, and each iterative scheme yields two sequences, which converge monotonically from above and below, respectively, to a maximal solution and a minimal solution of the finite difference system. This monotone convergence property leads to upper and lower bounds of the solution in each iteration as well as an existence‐comparison theorem for the finite difference system. Sufficient conditions for the uniqueness of the solution and some techniques for the construction of upper and lower solutions are obtained, and numerical results for a two‐point boundary‐value problem with known analytical solution are given. © 2001 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 17:347–368, 2001
A germacranolide and three hydroxybenzyl alcohol derivatives from Hieracium murorum and Crepis bocconi
Authors: Zidorn Christian , Ellmerer‐Müller Ernst P. , Stuppner Hermann
Published: August 2002

The methanol extract of sub‐aerial parts of Hieracium murorum L. gave germacra‐7αH‐1(10)E,4Z,11­(13)‐trien‐12,8α‐olide‐15‐oic acid (15 → 1)‐β‐D‐glucopyranosyl ester (1), a new sesquiterpenoid of the germacrane‐type, and two new 4‐hydroxybenzyl alcohol derivatives, 4‐hydroxy‐cinnamomic acid 4‐β‐D‐glucopyranosyloxybenzyl ester (2) and 3‐hydroxy‐2‐[(4‐hydroxy‐phenyl)‐acetoxy]‐3‐methyl‐butyric 4‐β‐D‐glucopyranosyloxybenzyl ester (3). The methanol extract of sub‐aerial parts of Crepis bocconi P. D. Sell gave 4‐hydroxybenzoic acid 4‐β‐D‐glucopyranosyloxybenzyl ester (4), another new 4‐hydroxybenzyl alcohol derivative. The structures of these compounds were established by means of MS and one‐ and two dimensional‐NMR experiments. Copyright © 2001 John Wiley & Sons, Ltd.
Issues and methodological challenges in developing and evaluating health care interventions for older people with diabetes mellitus, part 1
Authors: Forbes A , Berry J , While A , Hitman GA , Sinclair AJ
Published: August 2002

This review (part one of a two‐part review) discusses a number of different issues relating to the development and evaluation of interventions for the diabetes care of older people. The review draws on the experience of a pilot study examining a new model of care for older frail people with type 2 diabetes, which comprised a specially developed clinical protocol to support district nurses in carrying out a diabetic annual review for the ‘older housebound’. The review examines the difficulties encountered in conducting research with this vulnerable subset of the population of people with diabetes and suggests how they may be overcome. Particular attention is directed at clarifying the research population, the validity of the proposed intervention, alternative approaches to the care of the older population with diabetes, sample selection and recruitment and outcome measures. Copyright © 2002 John Wiley & Sons, Ltd.
Conducting pharmacoepidemiologic research in Denmark
Authors: Hallas Jesper
Published: August 2002

Denmark has one of the worlds most comprehensive registration of its citizens' use of medical and social services. Most databases are population‐based and of very high quality. Virtually all employ a mutual person identifier, which renders it technically possible to link any of them with others. There are two prescription registries of interest for research, the OPED and the NJPD, each covering 0.5 million persons. The content of these are described in brief. The most recent Danish data protection act can be viewed as a liberalization of prevailing registry practice. Our most important obstacles for performing record‐linkage studies are costs, academic resources and a lack of generally accepted guidelines on the ethics of observational research. Copyright © 2001 John Wiley & Sons, Ltd.
Effects of nematic coupling on the phase behaviour of nematogen mixtures
Authors: Benmouna Farida , Maschke Ulrich , Coqueret Xavier , Benmouna Mustapha
Published: August 2002

The phase behaviour of binary nematogen mixtures of side‐chain liquid crystal crosslinked polymers and low molecular weight liquid crystals is investigated with particular emphasis on the effects of nematic coupling. The cross nematic quadrupole parameter ν12is assumed to be proportional to the geometric average of ν11and ν22characteristic of single nematogens. In the weak coupling limit, the proportionality constant is lower than 1, and the phase diagram exhibits a reduced miscibility of the nematogens. In the case of strong coupling, the proportionality constant exceeds 1 resulting in higher miscibility. This is characterized by a nematic order that extends to temperatures above the upper nematic–isotropic transition temperature. A wide region of miscibility emerges showing a single nematic phase. Nematogens having similar nematic–isotropic transition temperatures exhibit different phase properties from systems with widely separated transition temperatures. Effects of the polymer volume fraction at crosslinking, rubber elasticity parameters of the network, and the Flory–Huggins interaction parameter on the equilibrium phase diagram of these systems are discussed.

© 2001 Society of Chemical Industry
Surface characterization and study of Langmuir films of poly(4‐vinylpyridine) quaternized with n‐alkylbromide
Authors: Gargallo Ligia , Miranda Beatriz , Ríos Hernán , González‐Nilo Fernando , Radić Deodato
Published: August 2002

The surface behaviour of poly(4‐vinylpyridine)s (P4VP) quaternized with four different alkyl chains (pentyl, hexyl, octyl and decy bromide) were studied. Surface pressure–area isotherms (π–A) at the air–water interface were determined. Depending on the length of the side‐chains, the π–A isotherms show a plateau region. An extensive plateau is observed for n > 6. The plateau pressures are similar for n  = 8 and n  = 10. The monolayers are stable and exhibit hysteresis phenomena. Brewster angle microscopy (BAM) is used to monitor the monolayer topography of the polymer on water subphase. To obtain information about the surface energy (SE) and the degree of hydrophobicity of these systems, we have estimated the critical surface tension, γc, and the dispersion force and polar contributions to SE, γD and γP, respectively, by measurements of the contact angle (CA) of water and bromobenzene on the polymer surface. The results obtained are depend on the length of the alkyl lateral chain of the functionalized polymers.

© 2001 Society of Chemical Industry
Dielectric monitoring of curing of liquid oligomer‐modified epoxy matrices
Authors: Kortaberria G , Arruti P , Mondragon I
Published: August 2002

Dielectric measurements were performed in ‘real‐time’ at several temperatures to follow polymerization reactions on blends of a diglycidyl ether of bisphenol A (DGEBA) epoxy resin with 4, 4′‐diaminodiphenylmethane (DDM) hardener and different amounts of polyoxypropylenetriamine (POPTA) oligomer. These systems exhibit phase separation induced by molar mass increasing through curing of the resin. Monitoring of phase separation and vitrification (related to the α‐relaxation) was performed by this technique. The results are compared with those for the unmodified resin–hardener mixture. The change of the main α‐relaxation with cure time, cure temperature, and amount of modifier was measured for the mixtures. This change of the main relaxation through curing in the frequency domain was indicative of the cure reaction advancement, because of its dependence on the viscosity of the medium. The change of the ionic conductivity during curing was also analysed, showing its dependence upon cure temperature.

© 2001 Society of Chemical Industry
Rheology of polyurethane solutions with different solvents
Authors: de Vasconcelos C L , Martins R R , Ferreira M O , Pereira M R , Fonseca J L C
Published: August 2002

Hard segment hydrogen bonding interactions in a particular polyurethane segmented copolymer have been analysed through a viscometric approach to determine the behaviour of polyurethane solutions with different solvent compositions. Analysis of log ηspversus log c[η] master curves (solely comprising dilute and semidilute regimes) showed that these systems could be differentiated by the slope of the first part of the curve (dilute regime), the characteristic reduced concentration c*[η], and the slope of the second part of the curve (semidilute regime), differences which were related to a possible occurrence of polymer aggregates. Experiments with solutions in the concentrated regime, at different temperatures, were used to relate non‐Newtonian behaviour to hydrogen bonding.

© 2001 Society of Chemical Industry
Altering educational environments through positive peer reporting: Prevention and remediation of social problems associated with behavior disorders
Authors: Skinner Christopher H. , Neddenriep Christine E. , Robinson Sheri L. , Ervin Ruth , Jones Kevin
Published: August 2002

Typical classroom management procedures designed to reduce instances of inappropriate social behavior (i.e., tattling and punishment systems) may adversely impact the social development and social relations of students with behavior and/or social emotional disorders. Two alternative procedures where students are encouraged to monitor and report incidental prosocial behaviors are described and research supporting their effectiveness in remedying and preventing social interaction problems within classroom environments are reviewed. Recommendations for future research on altering classroom environments so that peers encourage and support classmates' incidental prosocial behavior are provided. © 2002 Wiley Periodicals, Inc.
Self‐modeling as an effective intervention for students with serious emotional disturbance: Are we modifying children's memories?
Authors: Kehle Thomas J. , Bray Melissa A. , Margiano Suzanne G. , Theodore Lea A. , Zhou Zheng
Published: August 2002

The intent of this article is to consider similarities between the research on the alteration of memory, and that on the modification of behavior through viewing edited self‐modeling videotapes that depict exemplary behavior. A considerable number of studies unequivocally show that memory can be altered through several mechanisms, including visual techniques. However, there is limited research indicating that alteration of memory results in valued and adaptive behavioral change. This article explores a tenable explanation for the research finding that self‐modeling is an effective intervention for students with behavior disorders. It was hypothesized that when participants view a change in their behavior, their memories and self‐beliefs subsequently change to be in concert with that shown on the edited videotape. Perhaps as the individuals repeatedly view the videotapes, they alter their memory of engagement in past maladaptive behavior, with an adaptive memory of exemplary behavior. Further, they may come to believe that they were always capable of exhibiting such behavior. © 2002 Wiley Periodicals, Inc.
Identifying and promoting social competence with African American preschool children: Developmental and contextual considerations
Authors: Mendez Julia L. , McDermott Paul , Fantuzzo John
Published: August 2002

School psychologists and teachers are frequently asked to assess the level of social competence of preschool children as one indicator of their academic readiness. However, many assessment instruments available to psychologists working in early childhood settings fail to consider important contexts where children acquire social competencies. This study presents a comprehensive picture of multiple constructs that play a role in understanding African American preschool children's social competence. Domains of temperament, language, self‐regulation, and peer play were assessed within a classroom context for a sample of 139 low‐income African American children attending Head Start. Findings support the importance of considering both children's developmental stage and their gender when evaluating aspects of social competence, particularly temperament and interactive peer play abilities. As a group, younger boys experienced the greatest difficulties with initiating and sustaining play activities with classmates. Language abilities and self‐regulation were significantly greater among older preschool children. Implications for school psychologists conducting preschool assessment, intervention, and outreach to parents and teachers within early childhood settings are discussed. © 2002 John Wiley & Sons, Inc.