bluuebunny/crossref_metadata_2025 huggingface dataset:
Striatopallidal neurons are selectively protected by neurturin in an excitotoxic model of Huntington's disease
Authors: Marco Sònia , Pérez‐Navarro Esther , Tolosa Eduard , Arenas Ernest , Alberch Jordi
Published: August 2002

Excitotoxicity has been involved in the pathogenesis of several neurodegenerative disorders. Using intrastriatal quinolinic acid (QUIN) injection as an animal model of Huntington's disease, we attempt to identify the neurotransmitter phenotype of striatal projection neurons protected by neurturin (NRTN). Control or NRTN‐secreting cell lines were grafted in the striatum before QUIN injection and striatal projection neurons were examined by retrograde Fluorogold labeling and in situ hybridization. Intrastriatal grafting of NRTN‐secreting cell line selectively prevented the loss of striatopallidal neurons and also the decrease in the mRNA levels for their markers (glutamic acid decarboxylase 67 and preproenkephalin) induced by QUIN, without affecting striatonigral neurons. Thus, our findings show that NRTN is a selective neuroprotective factor for striatopallidal neurons, suggesting that it might be a candidate for the treatment of movement disorders in which this neuronal population is affected. © 2002 Wiley Periodicals, Inc. J Neurobiol 50: 323–332, 2002; DOI 10.1002/neu.10033
Local error estimates of FEM for displacements and stresses in linear elasticity by solving local Neumann problems
Authors: Ohnimus S. , Stein E. , Walhorn E.
Published: August 2002

In this paper we present two types of local error estimators for the primal finite‐element‐method (FEM) by duality arguments. They are first derived from the (explicit) residual error estimation method (REM) and then—as a new contribution—from the (implicit) posterior equilibrium method (PEM) using improved boundary tractions, gained by local post‐processing with local Neumann problems, with applications in elastic problems. For the displacements a local error estimator with an upper bound is derived and also a local estimator for stresses. Furthermore—for better numerical efficiency—the residua are projected energy‐invariant onto reference elements, where the local Neumann problems have to be solved. Comparative examples between REM‐ and PEM‐type local estimators show superior effectivity indices for the latter one. Copyright © 2001 John Wiley & Sons, Ltd.
Optimal discretizations in adaptive finite element electromagnetics
Authors: McFee S. , Giannacopoulos D.
Published: August 2002

One of the primary objectives of adaptive finite element analysis research is to determine how to effectively discretize a problem in order to obtain a sufficiently accurate solution efficiently. Therefore, the characterization of optimal finite element solution properties could have significant implications on the development of improved adaptive solver technologies. Ultimately, the analysis of optimally discretized systems, in order to learn about ideal solution characteristics, can lead to the design of better feedback refinement criteria for guiding practical adaptive solvers towards optimal solutions efficiently and reliably. A theoretical framework for the qualitative and numerical study of optimal finite element solutions to differential equations of macroscopic electromagnetics is presented in this study for one‐, two‐ and three‐dimensional systems. The formulation is based on variational aspects of optimal discretizations for Helmholtz systems that are closely related to the underlying stationarity principle used in computing finite element solutions to continuum problems. In addition, the theory is adequately general and appropriate for the study of a range of electromagnetics problems including static and time‐harmonic phenomena. Moreover, finite element discretizations with arbitrary distributions of element sizes and degrees of approximating functions are assumed, so that the implications of the theory for practical h‐, p‐, hp‐ and r‐type finite element adaption in multidimensional analyses may be examined. Copyright © 2001 John Wiley & Sons, Ltd.
Genetic algorithm for discrete‐sizing optimal design of trusses using the force method
Authors: Kaveh A. , Kalatjari V.
Published: August 2002

In the process of discrete‐sizing optimal design of truss structures by Genetic Algorithm (GA), analysis should be performed several times. In this article, the force method is employed for the analysis. The advantage of using this method lies in the fact that the matrices corresponding to particular and complementary solutions are formed independently of the mechanical properties of members. These matrices are used several times in the process of the sequential analyses, increasing the speed of optimization. The second feature of the present method is the automatic nature of the prediction of the useful range of sections for a member from a list of profiles with a large number of cross‐sections. The third feature consists of a contraction process developed to increase the efficiency of the GA by which an optimal design for the first sub‐string associated with member cross‐sections is obtained. Improved designs are achieved in subsequent cycles by reducing the length of sub‐strings. Copyright © 2002 John Wiley & Sons, Ltd.
A Fourier method for computing the perturbation to a two‐dimensional electric potential by a conductor of arbitrary shape
Authors: Huestis Stephen P.
Published: August 2002

Introducing an electric conductor into a region pervaded by an initial electric potential perturbs that potential by inducing a charge distribution on the conductor's surface, necessary to guarantee that the surface is an equipotential of the total potential. Some numerical method is required to compute the perturbation potential, when the conductor's shape does not admit a standard analytic solution. For two‐dimensional situations, a method is proposed for solving for the perturbation potential that involves expansion of the boundary perturbation potential and its normal derivative as truncated Fourier series. This boundary potential is known to within an additive constant from the requirement that its sum with the initial potential must be a constant. The standard representation theorem for the Dirichlet problem gives a consistency relation between the boundary function and its normal derivative, which here becomes a set of linear algebraic relations between Fourier series coefficients, with matrix entries found by appropriate applications of the fast Fourier transform. These are solved for the boundary derivative coefficients; at any point exterior to the conductor, the perturbation potential can then be evaluated from the two sets of Fourier coefficients, using further application of the fast Fourier transform. Examples are shown for two conductor shapes, with several initial potentials. © 2001 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 17: 673–683, 2001
Asymmetric hydrogenation of ketones catalyzed by zeolite‐supported gelatin–Fe complex
Authors: Zhang Xi , Geng Yan , Han Bing , Ying Mao‐Ya , Huang Mei‐Yu , Jiang Ying‐Yan
Published: August 2002

Zeolite‐supported gelatin–iron complex (zeo–gelatin–Fe) was prepared from zeolite, gelatin and ferric chloride, and was found to be useful as a chiral catalyst for the asymmetric hydrogenation of some ketones to corresponding chiral alcohols, such as 2‐butanone to (S)‐2‐butanol, acetophenone to (R)‐1‐phenylethanol, diacetone alcohol to (S)‐2‐methyl‐2,4‐pentane‐diol, 3‐methyl‐2‐butanone to (R)‐3‐methyl‐2‐butanol and 4‐methyl‐2‐pentanone to (R)‐4‐methyl‐2‐pentanol in 52–100% optical yields, respectively, at 20 °C and under atmospheric hydrogen pressure. In the case of asymmetric hydrogenation of 3‐methyl‐2‐butanone to (R)‐3‐methyl‐2‐butanol, when a proper content of iron in the zeo–gelatin–Fe complex and suitable reaction conditions were selected, the product and optical yields could be amounted to 80 and 100%, respectively, and the zeo–gelatin–Fe complex catalyst could be reused several times without remarkable change in the optical catalytic activity. Copyright © 2001 John Wiley & Sons, Ltd.
Separation of underivatised triterpene acids by capillary supercritical fluid chromatography
Authors: Tavares Maria Cecília H. , Vilegas Janete H. Yariwake , Lanças Fernando M.
Published: August 2002

Capillary supercritical fluid chromatography with flame ionisation detection was used for the separation of some underivatised triterpene acids such as betulinic, oleanolic, polpunonic and ursolic acids. Supercritical fluid chromatography showed advantages over capillary gas chromatography since derivatisation was not required and separation was obtained in less than 15 min with high efficiency and good resolving power. Copyright © 2001 John Wiley & Sons, Ltd.
Identification of hydrolysable tannins in the reaction zone of Eucalyptus nitens wood by high performance liquid chromatography–electrospray ionisation mass spectrometry
Authors: Barry K. M. , Davies N. W. , Mohammed C. L.
Published: August 2002

The first detailed analysis of the phenolic constituents of the reaction zones (tissue of antimicrobial defence) from the sapwood of a Eucalyptus spp. is presented. Plantation‐grown Eucalyptus nitens trees with stem decay resulting from pruning wounds were sampled and extracts were prepared from healthy sapwood and from reaction zone tissue. Analysis by HPLC with ESI‐MS revealed that a diverse range of hydrolysable tannins are present in both healthy sapwood and in reaction zone extracts, including over 30 gallotannins, ellagitannins and phenols. Eight tannins were unequivocally identified, including the gallotannins tri‐O‐galloyl‐β‐D‐glucose, tetra‐O‐galloyl‐β‐D‐glucose and penta‐O‐galloyl‐β‐D‐glucose, and the ellagitannins pedunculagin, tellimagrandin I, casuarinin, casuarictin and tellimagrandin II. The phenols gallic acid, ellagic acid and catechin were also identified. The ellagitannins (particularly pedunculagin) are considerably more abundant in the reaction zone than in the healthy sapwood and may contribute to the effectiveness of the reaction zone as an antimicrobial barrier. Copyright © 2001 John Wiley & Sons, Ltd.
Parameters affecting microwave‐assisted extraction of withanolides
Authors: Kaufmann Béatrice , Christen Philippe , Veuthey Jean‐Luc
Published: August 2002

Focused microwave‐assisted extraction was applied to the extraction of three main withanolides from air‐dried leaves of Iochroma gesnerioides, namely, withaferin A, iochromolide and withacnistin. Six extraction variables, i.e. nature and volume of extracting solvent, sample moisture, extraction time, power of irradiation and particle size, were investigated with respect to the recovery of withanolides. The most favourable conditions were obtained by using powdered plant material (<220 µm), previously impregnated with water for 15 min, and extracted with methanol for 40 s at 25 W. The results obtained using the optimised method were compared to those achievable with Soxhlet extraction. Copyright © 2001 John Wiley & Sons, Ltd.
Normal and abnormal development of the urogenital tract
Authors: Cuckow Peter M. , Nyirady Peter , Winyard Paul J. D.
Published: August 2002

An understanding of the normal development of the urogenital tract, at both the structural and molecular level, gives an insight into the mechanisms involved in renal pathology. In this review we will outline embryology of normal and abnormal renal development and discuss the function of some of the key regulatory molecules which have been described recently. Copyright © 2001 John Wiley & Sons, Ltd.
Second trimester ultrasound screening for chromosomal abnormalities
Authors: Shipp Thomas D. , Benacerraf Beryl R.
Published: August 2002

The use of prenatal ultrasound has proven efficacious for the prenatal diagnosis of chromosomal abnormalities. The first sonographic sign of Down syndrome, the thickened nuchal fold, was first described in 1985. Since that time, multiple sonographically‐identified markers have been described as associated with Down syndrome. The genetic sonogram, involving a detailed search for sonographic signs of aneuploidy, can be used to both identify fetuses at high risk for aneuploidy and, when normal, can be used to decrease the risk for aneuploidy for a pregnancy when no sonographic markers are identified. Combining the genetic sonogram with maternal serum screening may be the best method of assessing aneuploidy risk for women who desire such an assessment in the second trimester. Trisomy 18, Trisomy 13, and triploidy are typically associated with sonographically identified abnormalities and have a high prenatal detection rate. The use of the described sonographic signs in low‐risk women requires further investigation, however, patients at increased risk for aneuploidy due to advanced maternal age or abnormal serum screening can benefit from a genetic sonogram screening for sonographic signs of aneuploidy to adjust their baseline risk of an affected fetus. Copyright © 2002 John Wiley & Sons, Ltd.
A high price to pay for self‐neglect
Authors: Steel JM , Campbell IW , Nawroz IM
Published: August 2002

An exceptionally poorly controlled non‐compliant young woman with Type 2 had numerous spontaneous abortions and an abnormal stillborn baby. She developed severe complications of diabetes from which she died at the age of 32 years only seven years after diagnosis. Copyright © 2000 John Wiley & Sons, Ltd.
Who reads Internet materials about diabetes?
Authors: Udovichenko Oleg V. , Voloshin Vladimir E.
Published: August 2002

Use of the Internet to spread information about diabetes is quite important today. Data about the potential auditorium of ‘diabetic’ websites is needed for successful work in this field. We conducted a survey aiming to evaluate the auditorium of such websites and clarify its beliefs concerning diabetes. We used a simple questionnaire, which consisted of six questions about reasons for the respondents' interest in this problem and their professional status, level of knowledge about diabetes and position concerning insulin injections in public places. On the basis of their answers 74 respondents may be divided into four categories: people with diabetes (25%), their friends/relatives (34%), healthcare professionals (HCPs) (11%) and ‘others’ (30%). Opinions of these groups concerning continuing working, pregnancy and prognosis of diabetes were identical to those of expert diabetologists in 27–96%. We also analysed lack of knowledge about diabetes (inability to give an answer) among different groups of respondents. It was more common for ‘others’ (41–59% in different questions) and much less frequent (0–24%) in the three other groups. Concerning insulin injections in the presence of other people the rate of the ‘It's possible’ answer increased in the order ‘others–patients–friends/relatives–HCPs’ and was estimated as 26–27–32–60%. This may indicate that society's potential tolerance to insulin injections may be even higher than persons with diabetes think. This study showed the main groups of visitors of the diabetes‐oriented websites. We demonstrated also great ability of the Internet to analyse people's positions, including medical topics. Copyright © 2000 John Wiley & Sons, Ltd.
Inpatient treatment of depression and associated hospital charges
Authors: Ackerman Deborah L. , Unützer Jürgen , Greenland Sander , Gitlin Michael
Published: August 2002

Objective

We evaluated inpatient treatment of depression, prescribing patterns for antidepressants, and associated hospital charges.

Methods

We reviewed administrative data of the UCLA Neuropsychiatric Hospital between July 1994 and July 1997 for all 1698 hospitalizations for mood disorders. We evaluated drug utilization patterns and hospital charges by analysis of variance and multiple regression, and by stratifying on diagnosis, severity, age, and other factors.

Results

Length of stay was the major contributor to total charges, which included room charges and charges for services, procedures, supplies, and tests. The selective serotonin reuptake inhibitors (SSRIs) were prescribed most often (to 47% of patients), followed by the atypicals (heterocyclics, 12%), the tricyclics (TCAs, 7%), venlafaxine (7%) and the monoamine oxidase inhibitors (MAOIs, < 1%). The atypicals were given to the oldest patients. After controlling for length of stay, patient age, genders and comorbidity, the atypicals were associated with the highest total inpatient charges: $2000 more than MAOIs, $600 more than SSRIs, and $600 more than venlafaxine. Higher charges were the result of more expensive procedures, especially ECT.

Discussion

The SSRIs were the most commonly used antidepressant. Charges for antidepressant medications contributed only 0.5% of total inpatient charges. Patients receiving atypicals had among the highest total charges, partly because of the higher use of ECT. They may represent a more severely depressed group who have not responded to other antidepressants. Copyright © 2002 John Wiley & Sons, Ltd.
Blends of bacterial poly[(R)‐3‐hydroxybutyrate] with oligo[(R,S)‐3‐hydroxybutyrate]‐diol
Authors: Saad G R
Published: August 2002

The miscibility, melting and crystallization behaviour of poly[(R)‐3‐hydroxybutyrate], PHB, and oligo[(R,S)‐3‐hydroxybutyrate]‐diol, oligo‐HB, blends have been investigated by differential scanning calorimetry: thermograms of blends containing up to 60 wt% oligo‐HB showed behaviour characteristic of single‐phase amorphous glasses with a composition dependent glass transition, Tg, and a depression in the equilibrium melting temperature of PHB. The negative value of the interaction parameter, determined from the equilibrium melting depression, confirms miscibility between blend components. In parallel studies, glass transition relaxations of different melt‐crystallized polymer blends containing 0–20 wt% oligo‐HB were dielectrically investigated between −70 °C and 120 °C in the 100 Hz to 50 kHz range. The results revealed the existence of a single α‐relaxation process for blends, indicating the miscibility between amorphous fractions of PHB and oligo‐HB.

© 2002 Society of Chemical Industry
A method for modeling the current–voltage curve of a PV module for outdoor conditions
Authors: Marion B.
Published: August 2002

A method has been developed for modeling the current–voltage curve of a photovoltaic (PV) module for outdoor conditions. An indoor characterization procedure determines a PV module's temperature and irradiance correction factors, which are used in conjunction with equations to translate a reference curve to outdoor conditions of PV module temperature and irradiance. A PV technology's spectral response characteristics are accommodated in the equation for irradiance. The modeled and measured energy is compared for a one‐year period for seven PV modules of different technologies. The results validate the method's use for modeling the hourly performance of PV modules, and for modeling daily energy production for PV module energy rating purposes. Published in 2002 by John Wiley & Sons, Ltd.
Concurrent validity of the Slosson full‐range intelligence test: Comparison with the Wechsler intelligence scale for children–third edition and the Woodcock Johnson tests of achievement–revised
Authors: Bell Nancy L. , Rucker Marggi , Finch A.J. , Alexander Joanne
Published: August 2002

This study examined the concurrent validity of the Slosson Full‐Range Intelligence Test (S‐FRIT) by comparing S‐FRIT scores to the scores of the Wechsler Intelligence Scale for Children–Third Edition (WISC‐III) and the Woodcock‐Johnson Tests of Achievement–Revised (WJ‐R). Data from 123 elementary students' screening and psychological testing results were examined. Results revealed that the S‐FRIT scores were more related to overall intelligence, verbal, and math abilities than nonverbal intelligence, reading, or written language abilities. Further, it was found that 89% of the participants' S‐FRIT Full‐Range IQ scores fell within one standard deviation of their WISC‐III FSIQ scores, with an average discrepancy of 7.6 points. Discrepancies between S‐FRIT and WISC‐III scores were also examined by educational diagnostic categories and ability levels. Limitations and suggestions for future research are provided. © 2002 John Wiley & Sons, Inc.
The Hammett equation applied to the nucleophilic displacement of ions and ion pairs on substituted benzenesulphonates
Authors: Alunni Sergio , Pica Monica , Reichenbach Gustavo
Published: August 2002

Nucleophilic substitution on meta‐ and para‐substituted methyl benzenesulphonates was studied with two chloride salts with different structures: NBu4Cl or KCl‐Kryptofix 2,2,2. Treating the results with the Acree equation shows that the reaction proceeds by two reaction paths, one involving the chloride ion and the other, slower one, involving the ion pairs. Treating the results with the Hammett equation gives consistent data, and shows that ρ is positive and nearly the same for the two reaction paths (ρ ≈ +2). The reactivity of methyl p‐nitrobenzenesulphonate was compared with that of the corresponding ethyl derivative, and it is shown that the methyl derivative reacts faster than the ethyl derivative in both paths. The results are interpreted based on the assumption that in both paths a negative charge is developed on the leaving group in the transition state, and that the activated complex is linear. Copyright © 2001 John Wiley and Sons, Ltd.
Cyanocarbons: A classic example of discovery‐driven research
Authors: Webster Owen W.
Published: August 2002

Cyanocarbons are organic compounds bearing enough cyano functional groups to significantly alter their chemical properties. For example, tetracyanoethylene forms a stable anion radical, is a strong π acid, and readily substitutes its cyano groups. Tetracyanoethylene oxide reacts by addition across its carbon–carbon bond. Diazodicyanoimidazole cleaves nitrogen to form a superelectrophilic carbene, and pentacyanocyclopentadiene is about as acidic as perchloric acid. In this highlight, discovery‐driven research that fanned out from tetracyanoethylene to a multiperson effort at DuPont on cyanocarbon chemistry is narrated. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 210–221, 2002
Effect of catalysts on the reaction of an aliphatic isocyanate and water
Authors: Ni Hai , Nash Heather A. , Worden James G. , Soucek Mark D.
Published: August 2002

The kinetics of the reaction of aliphatic isocyanate with water were investigated with hexyl isocyanate as a model compound. The kinetic study was carried out with a titration method to determine the concentration of the isocyanate group as a function of time. Gas chromatography was used to augment the kinetic data obtained from the titration method. The effects of an organic acid [p‐toluene sulfonic acid monohydrate (p‐TSA)], a tertiary amine {diazabicyclo[2.2.2]octane (DABCO)}, and an organotin compound [dibutyltin dilaurate (DBTDL)] on the reaction were investigated for the conversion of isocyanate to a urea. Under the reaction conditions in this study, urea was the only product observed. The rate constants indicated that p‐TSA had low catalytic activity, DABCO had intermediate catalytic activity, and DBTDL had high catalytic activity. A reaction mechanism was proposed for each of the catalysts. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1677–1688, 2002
Crosslinkable maleimide copolymers for stable NLO properties
Authors: Serhatli İ. E. , Yagci Y. , Hattemer E. , Zentel R. , Schmälzlin E. , Hohenadl S. , Bräuchle C. , Meerholz K.
Published: August 2002

Second‐order, nonlinear optical polymers based on epoxy‐substituted methylvinylisocyanates and N‐substituted maleimides were synthesized and characterized with spectral and thermal analysis. The photocrosslinking and thermal‐crosslinking reactions of copolymers with different chromophore contents were studied. Thermally induced crosslinking during the poling process, performed at the glass‐transition temperature (Tg), was prevented by Tg being decreased through the addition of a plasticizer. Electrooptic coefficients (r33), measured for crosslinked and noncrosslinked systems, had similar absolute values and relaxation dynamics. This behavior was explained in terms of the similar rotational mobility of the chromophore units and the paucity of crosslinking sites. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1589–1595, 2001
Annealing‐induced increase of permeability and amorphous‐phase mobility in an ethylene–vinylacetate copolymer
Authors: Gelfer M. Y. , Waddon A. , Schmidt‐Rohr K. , Gale R. , Kleiner L. , Berggren R.
Published: August 2002

The 50% increased permeability after annealing of semicrystalline poly(ethylene/vinylacetate) containing 3 mol % vinylacetate is linked to increased mobility in the amorphous phase, as identified by line‐narrowing of 1H wideline nuclear magnetic resonance (NMR) spectra and by reduced cross‐polarization efficiency in 13C NMR. Other morphological parameters, such as crystallinity, measured as 30 to 35% by differential scanning calorimetry (DSC) and NMR, are hardly changed by annealing. Small‐angle X‐ray scattering and NMR studies, using spin diffusion as well as T1ρ and T1 relaxation, detected only a small increase in crystallite thickness. The annealing‐induced enhancement in segmental mobility in the amorphous regions corresponds to a temperature shift of about 10 K, from which an increase of the motional rate by a factor of 2 is estimated, and which can account for the enhancement in the permeability. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2774–2780, 2001
Analysis of blends of poly(styrene‐co‐acrylonitrile) with an epoxy/aromatic amine resin using scanning thermal microscopy
Authors: Barral L. , Cano J. , Díez F. J. , López J. , Ramírez C. , Abad M. J. , Ares A.
Published: August 2002

Using a microthermal analyzer TA Instruments 2990 μTA, we have analyzed the morphologies developed for the resin tetraglycidyl‐4,4′‐diaminodiphenylmethane cured with an aromatic amine 4,4′‐diaminodiphenylsulphone modified with different amounts of poly(styrene‐co‐acrylonitrile) (SAN) thermoplastic. The phase‐separation phenomenon induced by polymerization was also followed by scanning electron microscopy. Using the modulated local thermal‐analysis mode of μTA, the glass‐transition temperatures of different domains for each sample were evaluated. Dynamic mechanical analyzer experiments were made to evaluate the macroscopic thermal properties of the blends. A morphology was well established for all blends examined with these techniques showing a nodular structure, the epoxy‐rich phase, and a continuous phase, the SAN‐rich phase, that forms the matrix. From both microscopic and macroscopic thermal analyses, it is concluded that a phase separation exists for the blends investigated. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 284–289, 2002
Quantifying phase behavior in partially miscible polystyrene/poly(styrene‐co‐4‐bromostyrene) blends
Authors: Gorga Russell E. , Jablonski Erin L. , Thiyagarajan P. , Seifert Soenke , Narasimhan Balaji
Published: August 2002

The phase behavior of thin‐film blends of polystyrene (PS) and the random copolymer poly(styrene‐co‐4‐bromostyrene) (PBS) was studied with atomic force microscopy (AFM) and small‐angle X‐ray scattering (SAXS). Phase behavior was studied as a function of the PBS and PS degree of polymerization (N), degree of miscibility [controlled via the volume fraction of bromine in the copolymer (f)], and annealing conditions. The Flory–Huggins interaction parameter χ was measured directly from SAXS as a function of temperature and scaled with f as χ = f2χS–BrS [where χS–BrS represents the segmental interaction between PS and the homopolymer poly(4‐bromostyrene)] Simulations based on the Flory–Huggins theory and χ measured from SAXS were used to predict phase diagrams for all the systems studied. The PBS/PS system exhibited upper critical solution temperature behavior. The AFM studies showed that increasing f in PBS led to progressively different morphologies, from flat topography (i.e., one phase) to interconnected structures or islands. In the two‐phase region, the morphology was a strong function of N (due to changes in mobility). A comparison of the estimated PBS volume fractions from the AFM images with the PBS bulk volume fraction in the blend suggested the encapsulation of PBS in PS, supporting the work of previous researchers. Excellent agreement between the phase diagram predictions (based on χ measured by SAXS) and the AFM images was observed. These studies were also consistent with interdiffusion measurements of PBS/PS interfaces (with Rutherford backscattering spectroscopy), which indicated that the interdiffusion coefficient decreased with increasing χ in the one‐phase region and dropped to zero deep inside the two‐phase region. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 255–271, 2002
Anisotropic properties of poly(ethylene terephthalate) by Brillouin spectroscopy: Anisotropic properties of oriented bulk and nanostructured poly(ethylene terephthalate) determined by Brillouin spectroscopy and birefringence experiments
Authors: Anders Stefan H. , Eberle Reinhold , Peetz Ludwig , Krüger Jan‐Kristian , Göschel Ulrich , Pietralla Martin
Published: August 2002

Using Brillouin spectroscopy (BS), the tensor of the elastic constants of oriented poly(ethylene terephthalate) was determined for a variety of morphologies obtained by different uniaxial drawing procedures. The extreme values of the moduli along the drawing direction at frequencies of a few gigahertz were C33 = 40 GPa and C44 = 1.8 GPa. As a result of the invariants of the single‐phase aggregate model, the oriented state is dominated by the Reuss average even at extreme draw ratios and subsequent to a deformation‐induced crystallization. This is documented in both the BS orientation parameter and the BS mode numbers in comparison with birefringence. Additional spectral lines observed at draw ratios larger than 6 are discussed in relation to the formation of nanostructured phases. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1201–1213, 2002
Dynamic mechanical and dielectrical properties of poly(vinyl alcohol) and poly(vinyl alcohol)‐based nanocomposites
Authors: Cendoya Ione , López Daniel , Alegría Angel , Mijangos Carmen
Published: August 2002

In this article we report on the investigation of the dynamics of poly(vinyl alcohol) (PVA) and PVA‐based composite films by means of dielectric spectroscopy and dynamic mechanical thermal analysis. Once the characterization of pure PVA was done, we studied the effect of a nanostructured magnetic filler (nanosized CoFe2O4 particles homogeneously dispersed within a sulfonated polystyrene matrix) on the dynamics of PVA. Our results suggest that the α‐relaxation process, corresponding to the glass transition of PVA, is affected by the filler. The glass‐transition temperature of PVA increases with filler content up to compositions of around 10 wt %, probably as a result of polymer–filler interactions that reduce the polymer chain mobility. For filler contents higher than 10 wt %, the glass‐transition temperature of PVA decreases as a result of the absorption of water that causes a plasticizing effect. The β‐ and γ‐relaxation processes of PVA are not affected by the filler as stated from both dynamic mechanical thermal analysis and dielectric spectroscopy. Nevertheless, both relaxation processes are greatly affected by the moisture content. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1968–1975, 2001
Effects of socioeconomic status on presentation with acute lower respiratory tract disease in children in Salvador, Northeast Brazil
Authors: Nascimento‐Carvalho Cristiana M. , Rocha Heonir , Benguigui Yehuda
Published: August 2002

Two different socioeconomic groups of children with pneumonia were studied, and their clinical and demographic aspects were evaluated. The diagnosis of pneumonia was based on findings of cough and tachypnea, or on crackles on auscultation or on radiologically confirmed infiltrate. This was a prospective cross‐sectional study conducted at the Professor Hosannah de Oliveira Pediatric Center, which cares for children of lower socioeconomic status (PHOPC), and at one private hospital which cares for children from middle to high socioeconomic status (Aliança Hospital, AH). Demographics and clinical differences were assessed by the Pearson chi‐square test or Fisher's exact test as appropriate; means of continuous variables were compared by Mann‐Whitney U‐test.

In a 26‐month period, 3,431 cases were recruited. The 2,476 cases identified at the PHOPC were younger than the 955 identified at AH (2.2 ± 2.3 vs. 4.5 ± 3.1 years, P < 0.0001) and had higher scores for severity (3.5 ± 1.5 vs. 2.7 ± 1.7, P < 0.0001), duration of hospitalization (days) (10.9 ± 12.1 vs. 6.2 ± 7, P < 0.0001), frequency of tobacco smoker in the household (48% vs. 31%, P < 0.0001), cardiopathy (15.3% vs. 5.9%, P = 0.003), fever (44.4% vs. 36.3%, P = 0.0001), tachypnea (67.6% vs. 32.3%, P < 0.0001), crackles (69.5% vs. 64.9%, P = 0.02), somnolence (19.9% vs. 10.4%, P < 0.0001), malnutrition (13.7% vs. 5%, P < 0.0001), hospitalization rate (27.4% vs. 22.5%, P = 0.003), and death (0.9% vs. 0.1%, P = 0.009). However, other features were more frequent among AH cases: parent's university level of education (38.2% vs. 1.0%, P < 0.0001), underlying chronic illness (40.6% vs. 28.5%, P < 0.0001), asthma (62.7% vs. 50.8%, P = 0.01), rhinitis (9.2% vs. 0.4%, P < 0.0001), previous use of antibiotics (34.3% vs. 27.1%, P = 0.001), and wheezing (53.1% vs. 42.2%, P < 0.0001).

Children of lower socioeconomic status have more serious lower respiratory tract disease, whereas children with pneumonia of middle to high socioeconomic status have more allergic diseases (rhinitis, asthma) and wheezing. Pediatr Pulmonol. 2002; 33:244–248. © 2002 Wiley‐Liss, Inc.
Efficacy of once‐daily tobramycin monotherapy for acute pulmonary exacerbations of cystic fibrosis: A preliminary study*
Authors: Master Vahid , Roberts G.W. , Coulthard K.P. , Baghurst P.A. , Martin A. , Roberts M.E. , Onishko C.R. , Martin A.J. , Linke R.J. , Holmes M. , Jarvinen A. , Kennedy D. , Colebatch K.A. , Hansman D. , Parsons D.W.
Published: August 2002

Our objective was to compare the efficacy, safety, and microbiology of once‐daily intravenous (IV) tobramycin with conventional 8‐hourly tobramycin/ceftazidime IV therapy for acute Pseudomonas aeruginosa (PA) pulmonary exacerbations in cystic fibrosis (CF). CF patients with PA‐induced pulmonary exacerbations were allocated to receive either once‐daily tobramycin (Mono) or conventional therapy with tobramycin/ceftazidime given 8‐hourly (Conv). The two longitudinal groups received therapy in a double‐blind, randomized manner over a period of 2 years. Tobramycin doses were adjusted to achieve a daily area under the time‐concentration curve of 100 mg·hr/L in both groups. Results were assessed for both short‐term changes (efficacy and safety after 10 days of IV antibiotics during acute exacerbations) and long‐term changes (efficacy, safety, and sputum microbiology between study entry and exit).

Pulmonary function tests (PFTs) on admission were similar in both groups. After 10 days of IV antibiotics, absolute mean improvements in percent of predicted PFTs were 12.8, 12.1, and 13.7 for forced expiratory volume in 1 sec (FEV1), forced vital capacity (FVC), and forced expired flow between 25–75% of FVC (FEF25–75%) in the Conv group (n = 51 admissions( compared to 10.6, 9.9, and 10.6 in the Mono group (n = 47((P<0.05 for all). Sixteen percent in the Conv group and 15% of patients in the Mono group did not respond to therapy by day 10. Long‐term PFT patterns were similar for the Conv and Mono groups. The time between admissions did not differ. The Mono group showed a significant increase in tobramycin minimum inhibitory concentrations (MICs) against PA from study entry to study exit (P = 0.02, n = 27 strains); this failed to reach significance in the Conv group (P =  0.08, n = 25). There was no significant increase in the number of isolates, with MIC≥8 mg/L in both groups. No short‐ or long‐term changes in audiology or serum creatinine were found in either group. After 10 days of IV therapy, the urinary enzyme N‐acetyl‐beta‐d‐glucosaminidase/creatinine ratios increased in both groups (P0.05). This increase was greater in the Conv compared to the Mono group (P < 0.05).

We conclude that this pilot study indicates once‐daily tobramycin therapy to be as effective and safe as conventional 8‐hourly tobramycin/ceftazidime therapy. Combination antibacterial therapy appears to offer no clinical advantage over once‐daily tobramycin monotherapy. Tobramycin once‐daily monotherapy is a potential alternative to conventional IV antibacterial therapy which deserves further investigation, including the impact on susceptibility of PA to tobramycin. Pediatr Pulmonol. 2001; 31:367–376. © 2001 Wiley‐Liss, Inc.
Histamine H1 receptor activation inhibits the proliferation of human prostatic adenocarcinoma DU‐145 cells
Authors: Valencia Sandra , Hernández‐Angeles Adriana , Soria‐Jasso Luis‐Enrique , Arias‐Montaño José‐Antonio
Published: August 2002

Background

Histamine stimulates cell proliferation in some tumor cell lines through the activation of H1 receptors coupled to phosphoinositide hydrolysis. We therefore set out to study the presence of H1 receptors in the prostate cancer cell line DU‐145 and the effect of their stimulation on cell growth.

Methods

The presence of histamine receptors was studied by radioligand binding. Phosphoinositide hydrolysis was assessed by measuring [1H]‐inositol phosphate ([1H]‐IPs) accumulation and changes in the intracellular concentration of free Ca2+ ([Ca2+]i). Proliferation was assessed by cell counting and by [1H]‐thymidine incorporation.

Results

DU‐145 cells express H1 receptors (110±14 fmol/mg of protein) whose stimulation results in [1H]‐IPs accumulation (602±23% of basal, EC50 2.2±0.4 μM) and calcium mobilization (resting level 96±5 nM, Δ[Ca2+]i 517±32 nM, EC50 6.2±0.1 μM). Incubation with histamine (100 μM, 24 hr) resulted in a decrease in both cell number and [1H]‐thymidine incorporation, blocked by the H1 antagonist mepyramine (1 μM).

Conclusions

Histamine inhibits the proliferation of DU‐145 cells through the activation of H1 receptors coupled to phosphoinositide hydrolysis. Prostate 48:179–187, 2001. © 2001 Wiley‐Liss, Inc.
Structural basis for the appearance of a molten globule state in chimeric molecules derived from lysozyme and α‐lactalbumin
Authors: Joniau Marcel , Haezebrouck Petra , Noyelle Katrien , Van Dael Herman
Published: August 2002

The problem as to why α‐lactalbumin, in the absence of Ca2+, forms a molten globule intermediate, in contrast to its structural homologue lysozyme, has been addressed by the construction of chimeras of human lysozyme in which either the Ca2+‐binding loop or a part of helix C of bovine α‐lactalbumin were transplanted. Previously, we have shown that the introduction of both structural elements together in the lysozyme matrix causes the apo form of the resulting chimera to display molten globule behavior during the course of thermal denaturation. In this article, we demonstrate that this molten globule character is not correlated with the Ca2+‐binding loop. Also, the Del 101 mutant in which Arg101 was deleted to simulate the α‐lactalbumin conformation of the connecting loop between helix C and helix D, does not show a stable equilibrium intermediate. Rather, the molten globule character of the chimeras has to be related with a specific part of helix C. More particularly, attention is drawn to the four hydrophobic side‐chains I93, V96, I99, and L100, the lysozyme counterparts of which are constituted of less bulky valines and alanine. Our observations are discussed in terms of decreased stability of the native form and increased stability of the intermediate molten globule. Proteins 2001;44:1–11. © 2001 Wiley‐Liss, Inc.
Elucidating protein secondary structures using alpha‐carbon recurrence quantifications
Authors: Webber Charles L. , Giuliani Alessandro , Zbilut Joseph P. , Colosimo Alfredo
Published: August 2002

Secondary structures of proteins were studied by recurrence quantification analysis (RQA). High‐resolution, 3‐dimensional coordinates of alpha‐carbon atoms comprising a set of 68 proteins were downloaded from the Protein Data Bank. By fine‐tuning four recurrence parameters (radius, line, residue, separation), it was possible to establish excellent agreement between percent contribution of alpha‐helix and beta‐sheet structures determined independently by RQA and that of the DSSP algorithm (Define Secondary Structure of Proteins). These results indicate that there is an equivalency between these two techniques, which are based upon totally different pattern recognition strategies. RQA enhances qualitative contact maps by quantifying the arrangements of recurrent points of alpha carbons close in 3‐dimensional space. For example, the radius was systematically increased, moving the analysis beyond local alpha‐carbon neighborhoods in order to capture super‐secondary and tertiary structures. However, differences between proteins could only be detected within distances up to about 6–11 Å, but not higher. This result underscores the complexity of alpha‐carbon spacing when super‐secondary structures appear at larger distances. Finally, RQA‐defined secondary structures were found to be robust against random displacement of alpha carbons upwards of 1 Å. This finding has potential import for the dynamic functions of proteins in motion. Proteins 2001;44:292–303. © 2001 Wiley‐Liss, Inc.
Lactoferrin–melanin interaction and its possible implications in melanin polymerization: Crystal structure of the complex formed between mare lactoferrin and melanin monomers at 2.7‐Å resolution
Authors: Sharma Ashwani K. , Kumar S. , Sharma Vandana , Nagpal Akanksha , Singh Nagendra , Tamboli Irfan , Mani Indu , Raman G. , Singh Tej P.
Published: August 2002

The concentration of melanin determines the intensity of colors of the skin and hair of animals. Melanin pigments are tyrosine‐based polymers formed in melanocytes within specialized organelles called melanosomes. In order to understand the mechanism of melanin polymerization, lactoferrin, a basic protein with a pI value of 9.0, has been used to produce melanin. Lactoferrin is a monomeric iron‐binding protein with a molecular weight of 80 kDa. The crystals of lactoferrin were soaked in a solution containing dihydroxyphenylalanine (DOPA) and tyrosinase enzyme. These crystals were used for X‐ray intensity data collection. The intensity data were collected to 2.7‐Å resolution to an overall completeness of 91% with an Rsym of 0.071. The crystals belong to orthorhombic space group P212121 with cell dimensions: a = 85.0 Å, b = 99.8 Å, c = 103.4 Å. The structure was determined by molecular replacement method, using the model of diferric mare lactoferrin, and refined to an R‐factor 0.215 (Rfree = 0.287) for all the data to 2.7‐Å resolution. The final model comprises 5,281 protein atoms from 689 amino acids, 2Fe3+, 2CO ions, 2 indole‐5,6‐quinone molecules (IQ), and 73 water molecules. Two IQ molecules, one in each lobe, bind to lactoferrin. In the C‐lobe, the IQ binds in the iron‐binding cleft, whereas in the N‐lobe, it is located in the side pocket between two α‐helices, filled with solvent molecules in the native iron‐saturated mare lactoferrin. The IQ molecules interact with protein molecule mainly through glutamic acid in both lobes, without significant perturbation to the protein structure. The orientation of N‐ and C‐lobes in the present structure is similar to that observed in the native iron‐saturated protein. However, as a result of the binding of IQ molecules, the orientations of the domains N1, N2 and C1, C2 in the two cases differ slightly. Proteins 2001;45:229–236. © 2001 Wiley‐Liss, Inc.
Identification of novel inhibitors of calling and in vitro [14C]acetate incorporation by pheromone glands of Plodia interpunctella
Authors: Hirashima Akinori , Eiraku Tomohiko , Watanabe Yasuyuki , Kuwano Eiichi , Taniguchi Eiji , Eto Morifusa
Published: August 2002

Some octopamine agonists were found to suppress in vitro biosynthesis of the calling pheromone of the Indian meal moth, Plodia interpunctella. Isolated pheromone‐gland preparations incorporated sodium [14C]acetate at a linear rate for 3 h when incubated with the pheromone biosynthesis activating neuropeptide (PBAN). This incorporation was dependent on the dose of PBAN (up to 0.5 µM). Thin‐layer chromatography of a pheromone‐gland extract revealed quantitative incorporation of radioactivity into a product exhibiting the same mobility as (Z,E)‐9,12‐tetradecadienyl acetate, the main component of the calling pheromone of P interpunctella. Twenty‐seven octopamine agonists were initially screened using a calling behaviour bioassay of female P interpunctella. Four derivatives with activity in the nanomolar range were identified which were, in order of decreasing pheromonostatic activity: 2‐(2,6‐diethylphenylimino)thiazolidine > 2‐(2,6‐diethylphenylimino)oxazolidine > 2‐(2,6‐dimethylphenylimino)thiazolidine > 2‐(2‐ethylphenylimino)oxazolidine. These compounds also showed in vitro inhibitory activity in intracellular de novo pheromone biosynthesis. The results of the present study indicate that these derivatives could provide useful information in the characterization and differentiation of octopaminergic receptor types and subtypes.

© 2001 Society of Chemical Industry
Evaluation of food additives and low‐toxicity compounds as alternative chemicals for the control of Penicillium digitatum and Penicillium italicum on citrus fruit
Authors: Palou Lluís , Usall Josep , Smilanick Joseph L , Aguilar Maria‐José , Viñas Inmaculada
Published: August 2002

The effectiveness of low‐toxicity chemicals as possible alternatives to synthetic fungicides for the control of post‐harvest green and blue moulds of citrus was evaluated. A preliminary selection of chemicals, mostly common food additives, was made through in vivo primary screenings with oranges artificially inoculated with Penicillium digitatum or P italicum. Selected compounds and mixtures were tested as heated solutions in small‐scale trials. Immersion of artificially inoculated oranges or lemons for 120 s in solutions at 40.6 °C and natural pH of potassium sorbate (0.2 M), sodium benzoate (0.2 M) or mixtures (0.1 + 0.1 M) of potassium sorbate with sodium benzoate, sodium propionate or sodium acetate were the most effective organic acid salts tested and reduced green mould by 70–80% after 7 days of storage at 20 °C. The mixtures did not significantly enhance the effectiveness of potassium sorbate or sodium benzoate alone. These solutions were as effective as sodium carbonate or calcium polysulphide treatments and, in general, they were more effective on lemons than on oranges. Satisfactory control of green and blue moulds was obtained by dipping oranges for 150 s in solutions of sodium molybdate (24.2 mM) or ammonium molybdate (1.0 mM) at 48 or 53 °C, but not at 20 °C. At 53 °C, however, the effectiveness of hot water was not enhanced by either molybdate. Molybdenum salts at higher concentrations were phytotoxic and stained the fruit. At non‐phytotoxic concentrations, the effectiveness of these solutions was more influenced by temperature than by concentration. In general, the inhibitory effects of all compounds tested were not fungicidal but fungistatic and not very persistent. In conclusion, potassium sorbate, sodium benzoate and ammonium molybdate, among the wide range of chemicals tested, were superior for the control of post‐harvest Penicillium decay of citrus fruit.

© 2002 Society of Chemical Industry