bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal‐structure dependence of electroactive properties in differently prepared poly(vinylidene fluoride/hexafluoropropylene) copolymer films
Authors: Jayasuriya Ambalangodage C. , Schirokauer Adriana , Scheinbeim Jerry I.
Published: August 2002

The electroactive properties of two random copolymers of vinylidene fluoride (VDF) and hexafluoropropylene (HFP) were studied. The compositions were 95/5 and 85/15 mol % P(VDF/HFP). For each composition, three different film‐preparation methods were used—solvent casting, melt‐pressed quenched, and melt‐pressed slow‐cooled. The ferroelectric properties observed were strongly dependent on the preparation methods of the films as well as the HFP molar content of the samples. The highest remanent polarizations (Pr) obtained from electric displacement versus electric field (D‐E) hysteresis data are 80 and 50 mC/m2 for the 5 and 15% HFP solvent‐cast samples, respectively. The slow‐cooled samples do not exhibit any ferroelectric behavior for either the 5 or 15% HFP copolymers. It was also observed that both the 5 and 15% HFP slow‐cooled samples have a smaller electrostrictive response relative to the other two types of samples. Wide‐angle X‐ray diffraction and DSC results suggest that the 5% HFP sample has a higher crystallinity relative to the 15% HFP sample for each preparation method. In addition, different crystal phases form in the samples resulting from the different preparation methods. Fourier transform infrared results suggest that the slow‐cooled samples are in the nonpolar α phase, whereas the quenched and solvent‐cast samples are more likely in the polar β phase. The slow‐cooled samples do not show a switching peak in their nonpolar α‐phase crystalline state. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2793–2799, 2001
Correlation of the elution behavior in temperature rising elution fractionation and melting in the solid‐state and in the presence of a diluent of polyethylene copolymers
Authors: Mirabella Francis M.
Published: August 2002

Compositionally homogeneous poly(ethylene‐α‐olefin) random copolymers with 1‐butene and 1‐hexene comonomers have been studied. The melting of solution‐crystallized specimens of these copolymers in the presence of trichlorobenzene as a diluent with differential scanning calorimetry (DSC) is well correlated with analytical temperature rising elution fractionation (A‐TREF) elution temperature profiles. This indicates that the A‐TREF experiment is essentially a diluent melting experiment. Furthermore, the correction of the corresponding solid‐state melting endotherms of these copolymers with Flory's diluent melting equation yields curves that also correlate very well with the DSC diluent melting curves and the A‐TREF elution temperature profiles. Values of χ, the Flory–Huggins interaction parameter, are determined for these copolymers in trichlorobenzene. χ decreases as short‐chain branching increases. The A‐TREF elution temperature profiles of one of these copolymers are the same, within experimental error, for dilute‐solution crystallizations of the copolymer performed over an extremely broad time schedule (10 s to 3 days). This indicates the profound effect of the branches, as limiting points of the ethylene sequences, in controlling the crystal thickness distribution, which in turn controls the melting point in the presence of the diluent, or the elution temperature from the A‐TREF. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2819–2832, 2001
Simulation of phase‐separated structures of liquid‐crystalline polymer/flexible polymer blends
Authors: Yang Shenglin , Liang Borun
Published: August 2002

The phase‐separation kinetics of liquid‐crystalline polymer/flexible polymer blends was studied by the coupled time‐dependent Ginzberg–Landau equations for compositional order parameter ϕ and orientational order parameter Sij. The computer simulations of phase‐separated structures of the blends were performed by means of the cell dynamical system in two dimensions. The compositional ordering processes of phase separation are demonstrated by the time evolution of ϕ. The influence of orientational ordering on compositional ordering is discussed. The small‐angle light scattering patterns are numerically reproduced by means of the optical Fourier transformation of spatial variation of the polarizability tensor αij, and the azimuthal dependence of the scattering intensity distribution is interpreted. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2915–2921, 2001
Effect of the copolymer composition on the K and a constants of the Mark–Houwink equation: Styrene–methyl methacrylate random copolymers
Authors: Songkhla P. Na , Wootthikanokkhan J.
Published: August 2002

This article reports a study of the effect of composition in styrene–methyl methacrylate random copolymers on K and a constants in the Mark–Houwink equation. Copolymers with a variety of compositions and chain lengths were prepared through a controlled free‐radical copolymerization, with benzyl diethyldithiocarbamate and tetraethyl thiuram disulfide as iniferters. The synthesized products were analyzed with several techniques, including Fourier transform infrared, 1H NMR, gel permeation chromatography, and viscometry. By relating the determined constants K and a of various copolymers to their composition, we found that the constant varied nonlinearly with the composition. The constant a decreased with increasing poly(methyl methacrylate) (PMMA) content in the copolymer molecule up to 60 wt %. After that, the constant increased with the PMMA content, reaching the value of the PMMA homopolymer. However, the constant K initially increased with the PMMA content up to a critical composition (60 wt %) and subsequently decreased with further increasing PMMA content. These results suggest that the molecular weight of a polystyrene–PMMA random copolymer of known composition cannot be approximated with a simple linear equation comprising the K and a values of each relevant homopolymers. The aforementioned trends are qualitatively discussed in relation to some possible sequential distribution in the copolymer molecules and the resulting conformation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 562–571, 2002; DOI 10.1002/polb.10119
Long‐term growth of core‐set curl in poly(ethylene terephthalate) film
Authors: Greener J. , Gillmor J. R.
Published: August 2002

Solid polymeric films (plates) commonly exhibit only partial recovery after being subjected to a bending moment for some finite duration. This phenomenon, generally called bending recovery or core‐set, has been described and successfully modeled in past studies using the viscoelastic plate bending theory. In this study, the viscoelastic theory of core‐set curl was extended to account for physical aging effects during the bending recovery test. The contribution of physical aging was incorporated into the model through the effective time theory and assuming a thermorheologically simple behavior. The model was tested against long‐term core‐set data for a biaxially oriented poly(ethylene terephthalate) (PET) film under ambient conditions and was then used to map the effect of sample age on the evolution of core‐set curl over long times. The predictions of the model agreed favorably with the data, and the results underscored the strong retarding effect of physical aging on the rate of acquisition of core‐set curl in PET film at ambient temperature. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1957–1967, 2001
Participation of oncological outpatients in psychosocial support
Authors: Plass Angela , Koch Uwe
Published: August 2002

In total, 132 cancer patients in four oncology outpatient clinics in Hamburg completed a questionnaire consisting of a newly designed instrument for measuring psychosocial support. In this questionnaire, patients were asked about their knowledge of institutions offering support, their previous participation in psychosocial support, the reasons for participation and their experience with and attitude towards it. A second section consisted of standardized instruments: the EORTC QLQ‐C30 questionnaire (Aaronson), the Brief Symptom Inventory (Derogatis and Melisaratos), the List of Physical Complaints (von Zerssen and Koller) and the Impact of Event Scale (Horowitz). Descriptive and variance‐analytical methods were used for the analysis of results. Most respondents were women (88%). The largest group (72%) had a history of breast cancer. A total of 28% of the patients in the sample had participated in psychosocial support, about 4% of these in self‐help groups. Participants in psychosocial support did not differ from non‐participants in gender, but they were significantly younger. They showed considerably higher scores in emotional and physical distress than non‐participants, their attitude towards psychosocial support was more positive, and they had more knowledge about institutions offering support than non‐participants. The main reasons listed for their participation in psychosocial support were mental distress, a desire to obtain help, and the wish to cope with the illness. The main reason for not participating was sufficient support from the family, friends or doctors. Copyright © 2001 John Wiley & Sons, Ltd.
Inspiratory flow reserve in boys with Duchenne muscular dystrophy
Authors: De Bruin Pedro F. , Ueki Jun , Bush Andrew , Y. Manzur Adnan , Watson Ann , Pride Neil B.
Published: August 2002

Patients with advanced muscular dystrophy frequently develop ventilatory failure. Currently respiratory impairment usually is assessed by measuring vital capacity and the mouth pressure generated during a maximal inspiratory maneuver (PI,max), neither of which directly measures ventilatory capacity. We assessed inspiratory flow reserve in 26 boys [mean (SD) age 12.8 (3.8) years] with Duchenne muscular dystrophy (DMD) without ventilatory failure and in 28 normal boys [mean (SD) age 12.6 (1.9) years] by analyzing the ratio between the largest inspiratory flow during tidal breathing (V′I,max(t)) and during a forced vital capacity maneuver (V′I,max(FVC)), (V′I,max(t)/V′I,max(FVC)). We have compared this ratio with the forced vital capacity (FVC) and PI,max measured at functional residual capacity.

Mean PI,max was −90(30)cmH2O, average 112% (range 57–179%) of predicted values in control boys and −31(11)cmH2O, average 40% predicted values in DMD boys (control vs DMD, P < 0.001). FVC was reduced in DMD boys [59(20)% predicted values vs 86(10)% predicted values in controls, P < 0.01]. Absolute V′I,max(FVC) was strongly related to FVC in both control and DMD boys; V′I,max(FVC) (expressed as FVC · s−1) was not related to PI,max in either group. The mean V′I,max(t)/V′I,max(FVC) ratio was higher in DMD 0.22 (0.08) than in controls 0.12 (0.03) (P < 0.001) indicating a reduction in inspiratory flow reserve in DMD. Inspiratory flow reserve was within the normal range in 8 of 19 DMD patients with PI,max less than 50% of predicted values.

We conclude that measurement of inspiratory flow reserve (V′I,max(t)/V′I,max(FVC) ratio) provides a simple and direct assessment of dynamic inspiratory muscle function which is not replicated by static measurement of PI,max or vital capacity and might be useful in assessment of respiratory impairment in boys with Duchenne muscular dystrophy. Follow‐up studies are required to establish whether measures of inspiratory flow reserve are of clinical value in predicting subsequent ventilatory failure. Pediatr Pulmonol. 2001; 31:451–457. © 2001 Wiley‐Liss, Inc.
M13 endopeptidases: New conserved motifs correlated with structure, and simultaneous phylogenetic occurrence of PHEX and the bony fish
Authors: Bianchetti Laurent , Oudet Claudine , Poch Olivier
Published: August 2002

M13 endopeptidase alignments have focused mainly on mammalian sequences and on the active site region defining the catalytic sequence signatures. Aligning all available M13 from bacteria to human on a full‐length basis, we have performed a sequence analysis. This enabled us to highlight the origin and function of the M13 PHEX subtype family endopeptidase (phosphate regulating gene with homologies to endopeptidases on the X chromosome). New evolutionary conserved regions in both prokaryotes and eukaryotes have been detected and eukaryotic‐specific regions clearly delineated. Using the recently solved neprilysin structure, we have observed that all new motifs, except one, localize in the spatial vicinity of the previously reported catalytic signatures. Interestingly, a highly hydrophobic pocket containing three newly reported motifs is centered by the C‐terminal tryptophan residue. Extensive M13 searches in complete and in progress higher eukaryotic genomes have lead to the identification of Danio rerio as the simplest organism having PHEX. Finally, the human PHEX substrate, the parathyroid hormone‐related peptide, PTHrP107–139, is absent in bony fish: this suggests the existence of further PHEX substrates common to both bony fishes and higher vertebrates. Proteins 2002;47:481–488. © 2002 Wiley‐Liss, Inc.
Organoclays for controlled release of the herbicide fenuron
Authors: Hermosin M Carmen , Calderón M Jesús , Aguer Jean‐Pierre , Cornejo Juan
Published: August 2002

Organoclays were assayed as matrices in which to associate herbicides, with the aim of decreasing product losses that could give rise to water contamination from agricultural activities. Fenuron was selected as model of a very mobile and highly water‐soluble herbicide. Two different organoclays of high (A‐HDT) and low (H‐C18) reversible fenuron sorption were selected. Herbicide–organoclay complexes were prepared from the two organoclays and with two different fenuron contents (20 and 40 g AI kg−1) and two different mixing times, so as to form a series of weak and strong complexes. The release of fenuron from those complexes into water and water/soil suspensions gave values of T50 (time to release 50% of the fenuron content) ranging from 0.3 min to 2400 h. The total fenuron released in these closed systems ranged from 48 to 80% of the fenuron in the complex. The organoclay type (high or low sorptivity) had the greatest influence on fenuron release, followed by the strong or weak complex, suggesting that herbicide–organoclay interactions are the main factors controlling release. Soil column leaching experiments showed fenuron–organoclay complexes to be effective in reducing the peak herbicide concentration in the leachate to a half (6 µM) or a quarter (3 µM) of that obtained from the free technical compound (12 µM). Herbicide lost through leaching was reduced from 78% for the free technical fenuron to 50–30%, depending on the organoclay used as carrier and the strength of the complex. Bioassay with ryegrass showed that the weak fenuron/H‐C18 complex (40 g AI kg−1) gave the same herbicidal activity as technical fenuron. The potential suitability of low‐sorptive organoclays for conferring slow‐release properties on the fenuron complex has been demonstrated.

© 2001 Society of Chemical Industry
Herbicide sensitivity of transgenic multiple herbicide‐tolerant oilseed rape
Authors: Senior Ian J , Moyes Catherine , Dale Philip J
Published: August 2002

Glyphosate and glufosinate‐ammonium herbicide tolerance traits were combined into both winter and spring lines of Brassica napus L. This allowed the study of possible interactions between these transgenes in two genetic backgrounds when treated with a variety of herbicides. Selective herbicides that are commonly used within Brassica crops showed no adverse effects on the transgenic plants or their null controls. Lines containing both glyphosate and glufosinate transgenes remained tolerant to their respective herbicides, regardless of the presence of the second tolerance transgene. Lines containing only a single transgene retained tolerance to the encoded trait and did not show cross‐tolerance to the second. Null lines were killed by either herbicide. All plant lines, regardless of their transgene content, were found to be equally susceptible to three herbicides (paraquat, metsulfuron‐methyl and mecoprop), commonly used to remove volunteer B napus from succeeding crops and set‐a‐side land.

© 2002 Society of Chemical Industry
Improved preparation of amyloid‐β peptides using DBU as Nα‐Fmoc deprotection reagent
Authors: Tickler Anna K , Barrow Colin J , Wade John D
Published: August 2002

Previous studies have shown the amyloid peptides, Aβ 1‐40/42, to be exceptionally difficult to assemble by Fmoc‐solid phase peptide synthesis due to the high hydrophobicity of the C‐terminal segment and resulting on‐resin aggregation. We found that the use of the stronger and more efficient base, DBU, at a concentration of 2% in DMF for Nα‐Fmoc deprotection allowed substantially improved continuous flow solid phase assembly of the model peptide Aβ 29‐40/42 fragments. This suggested that, at least for these sequences, incomplete deprotection was a greater problem than incomplete amino acid acylation. This base was then used during the synthesis of both Aβ 1‐40 and Aβ 1‐42, up to and including Ser8, from which point 20% piperidine in DMF was utilized so as to avoid potential aspartimide formation at Asp7. By this means, the deprotection efficiency through the difficult C‐terminal portion of the sequence was much improved and resulted in increased availability of terminal amino groups for acylation. This simple strategy that obviates the need for special conditions significantly improved crude peptide quality and allowed considerable facilitation of subsequent purification. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
Recent insights into body weight control: From physiology to pathology
Authors: Krysiak Robert , Okopień Bogusław , Belowski Dariusz , Madej Andrzej , Herman Zbigniew Stanisław
Published: August 2002

Over the past several years, new modulators of feeding and body weight have been discovered, and our knowledge of the mechanisms and neurohumoral interactions between anorexigenic and orexigenic compounds has increased dramatically. This review aims to summarize the present knowledge of the role of leptin and several hypothalamic neuropeptides, such as neuropeptide Y (NPY), corticotropin‐releasing hormone (CRH) and melanocortins, in the regulation of appetite and body weight. It also presents the progress made in the design of interactions between leptin and hypothalamic peptides in the regulation of feeding. The role of these compounds in the pathogenesis of obesity in animals and humans, and their potential usefulness in the treatment of this disorder, are discussed. Copyright © 2000 European Peptide Society and John Wiley & Sons, Ltd.
Inhibition of P. falciparum by steroids isolated from Solanum nudum
Authors: Pabón Adriana , Carmona Jaime , Maestre Amanda , Camargo Mauricio , Blair Silvia
Published: August 2002

Resistance to antimalarials has been widely reported and constitutes a major problem around the world. In Colombia, resistance of P. falciparum to chloroquine has been reported as 47%–97%, to amodiaquine 3%–7% and to sulfadoxine‐pyrimethamine as 9%–13%. The search for new antimalarials is a priority and with this aim we studied the in vitro antimalarial activity of plants used by traditional healers.
 Incorporation of 3H‐hypoxanthine by the strain FCB‐2 of P. falciparum was used to measure the degree of inhibition produced by the steroids SN‐1 tumacone A (C29H44O5), SN‐2 tumacone B (C27H42O4), SN‐3 tumacoside A (C35H54O10), and SN‐4 tumacoside B (C33H52O9). All compounds were obtained from the dried stems and leaves of Solanum nudum. The mean growth inhibition of P. falciparum was 71%, 56%, 21% and 12% with each of the compounds SN‐1, SN‐2, SN‐3 and SN‐4. These results constitute an important discovery since they may account for the antimalarial properties of extracts of Solanum nudum by a sensitive method. Future work should include study of the in vivo anti‐malarial effect of these extracts. Copyright © 2002 John Wiley & Sons, Ltd.
The bonding character of AlSO isomers in quartet excited states: Ab initio and density functional theory studies
Authors: Bu Yuxiang
Published: August 2002

The geometries and the bonding properties have been predicted for four isomers of AlSO species in the quartet state at density functional theory and coupled cluster [CCSD(T)] all‐electron correlation levels with a large 6‐311+G(3df) basis set. Results have indicated that for the AlSO species in quartet state the lowest state is 4A″ state which corresponds to a cyclic structure; the other three isomers (cyclic, bent, and linear) are higher than the lowest state by 26.9 kcal/mol (cyclic 4A′), 19.4 kcal/mol (4A″), and 28.3 kcal/mol (linear AlSO 4Σ), respectively. The calculated dissociation energies for the lowest quartet state species (AlSO: 4A″) are 27.3 kcal/mol for the radical mechanism [M(2P)+SO(3Σ−)] and 154.7 kcal/mol for the mechanism [M(2P)+S(3P)+O(3P)]. Inspection of the bonding character indicates that the cyclic AlSO species in the lowest quartet state (4A″) should be classified as thiodioxide (similar to disulfide or dioxide), and the cyclic 4A′ state should be classified as thiosuperoxide. The bent AlSO(4A″) species has some thiosuperoxide character, while the linear AlSO(4Σ) structure should be classified as a molecular complex with a weak interaction bonding. However, this thiosuperoxide is not as ionic as LiO2 and LiSO and is also less ionic than the cyclic AlO2. In addition, the combinations of Al with SO species exhibit the amphoteric character of Al. © 2002 John Wiley & Sons, Inc. Int J Quantum Chem, 2002
Theoretical study of the effect of counterions on the structure of pyrrole oligomers
Authors: Tamm Tarmo , Tamm Jüri , Karelson Mati
Published: August 2002

The influence of counterions on the calculated properties of positively charged pyrrole oligomers is studied using the semiempirical AM1 and PM3 methods. The geometry and properties of the charged pyrrole oligomers are significantly affected by counteranions both in anti and syn conformations. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem 88: 296–301, 2002
Imposing bounds on the high‐order reduced density matrices elements
Authors: Valdemoro C. , Alcoba D. R. , Tel L. M. , Pérez‐Romero E.
Published: August 2002

A family of N‐representability conditions are imposed on the third‐ and fourth‐order reduced density matrix elements in order to ascertain that they are within bounds. These bounds are needed in the construction of high‐order reduced density matrices as well as in the correction of the matrices which result from the iterative solution of the standard and of the modified contracted Schrödinger equations. The results obtained for the fourth‐order reduced density matrix are strikingly good in two nontrivial cases. A new and more economical method for constructing the fourth‐order reduced density matrix in terms of the lower order ones is also reported here. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Theory of electronically nonadiabatic reactions: Rotational, Coriolis, spin–orbit couplings and the hyperquantization algorithm
Authors: Aquilanti V. , Cavalli S. , De Fazio D. , Volpi A.
Published: August 2002

An electronically nonadiabatic quantum mechanical approach to the atom–molecule reactive scattering is presented. The hyperquantization algorithm, developed by us to treat electronically adiabatic reactions, has been extended in order to consider the role of excited electronic states. Couplings of all the nuclear and electronic angular momenta of the system (spin–orbit, electronic, rotational, and Coriolis) are included in the treatment of the reaction dynamics. We specialize the theory for reactions of the X (2Pj)+H2 type, where X is a halogen atom, and give some numerical results for the example of fluorine. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Continuous flow stable isotope methods for study of δ13C fractionation during halomethane production and degradation
Authors: Kalin Robert. M. , Hamilton John. T.G , Harper David. B. , Miller Laurence G. , Lamb Clare , Kennedy James. T. , Downey Angela , McCauley Sean , Goldstein Allen H.
Published: August 2002

Gas chromatography/mass spectrometry/isotope ratio mass spectrometry (GC/MS/IRMS) methods for δ13C measurement of the halomethanes CH3Cl, CH3Br, CH3I and methanethiol (CH3SH) during studies of their biological production, biological degradation, and abiotic reactions are presented. Optimisation of gas chromatographic parameters allowed the identification and quantification of CO2, O2, CH3Cl, CH3Br, CH3I and CH3SH from a single sample, and also the concurrent measurement of δ13C for each of the halomethanes and methanethiol. Precision of δ13C measurements for halomethane standards decreased (±0.3, ±0.5 and ±1.3‰) with increasing mass (CH3Cl, CH3Br, CH3I, respectively). Given that carbon isotope effects during biological production, biological degradation and some chemical (abiotic) reactions can be as much as 100‰, stable isotope analysis offers a precise method to study the global sources and sinks of these halogenated compounds that are of considerable importance to our understanding of stratospheric ozone destruction. Copyright © 2001 John Wiley & Sons, Ltd.
Study of the electrospray ionization mass spectrometry of the proton pump inhibiting drug Omeprazole
Authors: Weidolf Lars , Castagnoli Neal
Published: August 2002

A detailed analysis of the product ion spectrum generated from the protonated molecule under ESI‐MS/MS conditions using a triple quadrupole mass spectrometer is reported for the gastrointestinal proton pump inhibitor Omeprazole. Unambiguous molecular composition data of the fragment ions were obtained with the aid of regioselectively 14C‐, 34S‐ and 18O‐labeled analogs. Attempts have been made to provide rational pathways for the formation of the fragment ions from four protonated omeprazole species. These results will facilitate the characterization of the complex metabolic fate of Omeprazole in humans, which involves the excretion of at least 50 metabolites. Copyright © 2001 John Wiley & Sons, Ltd.
Direct determination of glycosylation sites in O‐fucosylated glycopeptides using nano‐electrospray quadrupole time‐of‐flight mass spectrometry
Authors: Maček Boris , Hofsteenge Jan , Peter‐Katalinić Jasna
Published: August 2002

O‐Fucosylation is an unusual posttranslational modification present in several proteins that play important roles in physiological processes such as coagulation, cell signaling and metastasis. Although the exact function of the modification is still unclear, the number of proteins found to be modified is increasing, and there is a need for further structural and functional analyses. Here we report on a rapid and straightforward approach in the analysis of glycosylation status and determination of glycosylation sites in O‐fucosylated glycopeptides using nano‐electrospray quadrupole time‐of‐flight (nano‐ESI Q‐TOF) mass spectrometry. In a single measurement of previously chemically untreated O‐fucosylated peptides originating from the thrombospondin‐1 repeats, we were able to determine the glycosylation status of the analyzed peptide, the glycosylation site, and the glycan structure. The abundance of glycosylated peptide fragment ions in MS2 spectra suggests that nano‐ESI Q‐TOF mass spectrometry can be used as a general approach in structural studies of O‐fucosylation in proteins. Copyright © 2001 John Wiley & Sons, Ltd.
Multiresidue analysis of tranquilizers and the beta‐blocker Carazolol in meat by liquid chromatography/tandem mass spectrometry
Authors: Kaufmann Anton , Ryser Bianca
Published: August 2002

A fast and simple method for the quantification of a number of tranquilizers and the beta‐blocker Carazolol in pork and bovine kidney is described. Extracts are purified/concentrated by a solid phase extraction step and separated on a reversed phase column with an alkaline (ammonia) acetonitrile gradient. The electrospray tandem mass spectrometer is operated in positive ion multireaction monitoring mode. Resulting chromatograms are free of interfering peaks. The recovery is >75% for all analytes and the limit of detection <1 ppb, which is well below the current maximum residue limit for the various compounds. Copyright © 2001 John Wiley & Sons, Ltd.
N‐in‐one determination of retention factors for drugs by immobilized artificial membrane chromatography coupled to atmospheric pressure chemical ionization mass spectrometry
Authors: Kangas Heli , Kotiaho Tapio , Salminen Timo , Kostiainen Risto
Published: August 2002

Immobilized artificial membrane (IAM) chromatography is widely used in drug discovery for ranking the absorption properties of drug candidates. In this work an IAM chromatography method using atmospheric pressure chemical ionization mass spectrometric detection (IAM/APCI‐MS) was developed for the determination of log kIAM values for a mixture of compounds (9‐in‐one). Values were calculated from isocratic runs (0, 10, 20, 30, 35% acetonitrile) in both positive and negative modes. Good correlation (r2 = 0.97) was achieved for n‐in‐one results obtained with ammonium acetate buffer and mass spectrometry, compared with the traditional method involving single compound analysis with phosphate buffered saline and an ultraviolet detector. A gradient elution method providing fast determination of relative log kIAM values in a single IAM/APCI‐MS run was demonstrated for the same compounds. Copyright © 2001 John Wiley & Sons, Ltd.
Electron ionization mass spectral fragmentation of some isoprenoid glycidic ethers
Authors: Rontani J.‐F. , Rabourdin A. , Aubert C.
Published: August 2002

The electron ionization (EI) mass spectra of Z‐ and E‐2,3‐epoxy‐3,7,11,15‐tetramethylhexadecan‐1‐ol trimethylsilyl ethers are reported. These compounds present interesting fragmentation processes involving notably a transannular cleavage of the epoxide ring after transfer of the trimethylsilyl group. These pathways have been substantiated by deuterium labelling and comparison with the EI mass spectra of the isomeric 1,2‐epoxy‐3,7,11,15‐tetramethylhexadecan‐3‐ol trimethylsilyl ether and of the corresponding methyl ethers. Copyright © 2001 John Wiley & Sons, Ltd.
Temperature controller for thermal ionization mass spectrometry
Authors: Halas Stanislaw , Wójtowicz Artur , Nowak Jaroslaw , Durakiewicz Tomasz
Published: August 2002

We describe the use of a simple voltage stabilizer that controls the filament temperature (Tf) in the ion source of a thermal ionization mass spectrometer. The filament voltage (Vf) is measured by means of a separate pair of wires connected inside of the ion source in parallel to the wires supplying power. It has been demonstrated that Vf is directly proportional to Tf in a wide range of filament temperature. The Tf value is solely controlled by the reference voltage (Vr) that can be manually selected from a voltage divider or by means of a computer. Digital signals from the computer in the form of a series of pulses are transmitted opto‐electronically and subsequently converted to analog signals. The temperature controller described here was successfully applied for analysis of potassium concentration by the isotope dilution method. Copyright © 2001 John Wiley & Sons, Ltd.
Advances in the treatment of neonatal herpes simplex infections
Authors: Kimberlin David W.
Published: August 2002

Neonatal HSV disease is a potentially devastating illness with significant mortality and morbidity. Collaborative research efforts over the past 25 years have provided therapeutic options that were beyond hope just a generation ago. The use of high‐dose acyclovir for the treatment of acute neonatal HSV disease has reduced mortality rates to their lowest level ever. Application of PCR to clinical specimens from neonates suspected of having neonatal HSV infection largely has eliminated the need to perform invasive brain biopsies, while at the same time providing a new tool with which to re‐define the natural history of neonatal HSV disease. A limitation of PCR is the lack of standardisation in methodologies from laboratory to laboratory, which can impede a clinician's ability to interpret the PCR results. As such, all test results, including those from PCR, must be evaluated in the context of the patient's medical condition. Areas for continued research for further means of improvement in disease outcome include raising awareness of neonatal HSV disease so that the time between disease onset and the initiation of antiviral therapy can be shortened, as well as the evaluation of monoclonal antibodies as adjunctive therapy to high‐dose acyclovir. Utilisation of suppressive oral acyclovir following acute neonatal disease is another therapeutic option under clinical investigation with the potential to improve morbidity outcomes of neonatal HSV disease survivors. Copyright © 2001 John Wiley & Sons, Ltd.
Dengue fever and dengue haemorrhagic fever: challenges of controlling an enemy still at large
Authors: Kurane Ichiro , Takasaki Tomohiko
Published: August 2002

Dengue virus infections are a serious cause of morbidity and mortality in most tropical and subtropical areas of the world: mainly Southeast and South Asia, Central and South America, and the Caribbean. Understanding the pathogenesis of dengue haemorrhagic fever (DHF), the severe form of dengue illness, is a very important and challenging research subject. Viral virulence and immune responses have been considered as two major factors responsible for the pathogenesis. Virological studies are attempting to define the molecular basis of viral virulence. The immunopathological mechanisms appear to include a complex series of immune responses. A rapid increase in the levels of cytokines and chemical mediators apparently plays a key role in inducing plasma leakage, shock and haemorrhagic manifestations. It is likely that the entire process is initiated by infection with a so‐called virulent dengue virus, often with the help of enhancing antibodies in secondary infection, and then triggered by rapidly elevated cytokines and chemical mediators produced by intense immune activation. However, understanding of the DHF pathogenesis is not complete. We still have a long way to go. Copyright © 2001 John Wiley & Sons, Ltd.
Consequences of stream impoundment on fish communities in a small North American drainage
Authors: Taylor Christopher A. , Knouft Jason H. , Hiland Tim M.
Published: August 2002

We examined impoundment associated fish community changes in the Kinkaid Creek drainage of southern Illinois by comparing collections made in 1998 and 1999 with a pre‐impoundment survey conducted in 1958. We also analyzed other historical pre‐ and post‐impoundment collections made during the past 60+ years. A dramatic change in fish community structure occurred with the pre‐impoundment community dominated by cyprinids and the post‐impoundment community now dominated by centrarchids. In addition, a 50% increase in the number of fish species known from the Kinkaid Creek drainage has occurred, with 35% of all species known from Illinois now present in the drainage. This increase in species richness coincides with the extirpation of six native species. Possible explanations for the changes in the species assemblage and increased species richness include the introduction and dispersal of non‐native fish species and habitat alteration. Finally, we contend that processes, such as habitat alteration, must be considered when analyzing the pattern of increased species richness caused by non‐native species seen in North American drainages. Copyright © 2001 John Wiley & Sons, Ltd.
Speech Recognition Using Acoustic Similarity‐Based Primitives
Authors: Hayashi Takafumi , Mori Hiroki , Suzuki Motoyuki , Makino Shozo , Aso Hirotomo
Published: August 2002

This paper proposes an algorithm that automatically acquires a new recognition primitive by splitting the training sample so that the likeness of the whole training sample to the model is maximized. The primitive obtained by the proposed method is a primitive integrating several time‐continuous phonemes. It is called an acoustic similarity‐based primitive (ASP). The algorithm proposed in this paper performs in parallel ASP acquisition and ASP modeling by HMnet. The two are simultaneously optimized. In phoneme recognition experiments for six specified speakers, the recognition rate was improved by approximately 3.5% on the average, compared to the conventional phoneme HMnet, by increasing the number of candidates by approximately 14.6% on the average. A method is also proposed in which an ASP is built in a large‐vocabulary continuous speech recognition system. In a recognition experiment with eight specified speakers, the accuracy of word recognition was improved by approximately 2.6%, compared to the phoneme HMnet. © 2001 Scripta Technica, Syst Comp Jpn, 33(1): 8–17, 2002
Piezoresistive SXM sensors
Authors: Rangelow I. W. , Grabiec P. , Gotszalk T. , Edinger K.
Published: August 2002

The design, fabrication and evaluation of various microprobes for applications in scanning probe microscopy are presented. A piezoresistive cantilever with an integrated micro‐tip, as a basic structure, enables surface topography measurements with a resolution up to 0.1 nm. A conductive tip isolated from the cantilever was introduced for scanning capacitance microscopy and scanning electrostatic force microscopy. With this microprobe a capacitance between the micro‐tip and the surface in the range of 10−22F could be measured. Modification of the cantilever shape permits fabrication of the multipurpose systems for lateral force microscopy, which enables measurement of friction forces with a resolution of 1 nN. A femtocalorimeter for the detection of heat energy in the range of 50 nW Hz−0.5 was developed. A microbalance cantilever for ‘electronic nose’ applications makes it possible to determine picogram mass changes induced by chemical reactions in chemically sensitive coatings. A scanning near‐field thermal nanoprobe combines a thermal resolution of 10−3 K with a spatial resolution of 20 nm. Copyright © 2002 John Wiley & Sons, Ltd.
Analytical ultrahigh‐vacuum transmission electron microscopy applied to the study of Pd2Si island formation on Si(111) surfaces
Authors: Takeguchi Masaki , Tanaka Miyoko , Yasuda Hidehiro , Furuya Kazuo
Published: August 2002

Analytical ultrahigh‐vacuum transmission electron microscopy was applied to study the formation process of Pd2Si islands on Si(111) surfaces. The deposition of Pd onto the Si(111) surfaces at ∼670 K caused the formation of Pd2Si islands of size 10–40 nm. High‐resolution transmission electron microscopy (HRTEM) revealed an epitaxial interface, surface depression, bulk erosion of the substrate around the islands and a superstructure phase at the (0001) surface of the islands. Energy‐dispersive x‐ray spectroscopy (EDS) combined with HRTEM enabled us to identify the composition of the islands as Pd2Si. Electron energy‐loss spectroscopy indicated that the superstructure phase of the island (0001) surface was induced by the surface segregation of Si atoms. Copyright © 2001 John Wiley & Sons, Ltd.
Type I error in sample size re‐estimations based on observed treatment difference
Authors: Shun Zhenming , Yuan William , Brady William E. , Hsu Huang
Published: August 2002

Sample size re‐estimation based on an observed difference can ensure an adequate power and potentially save a large amount of time and resources in clinical trials. One of the concerns for such an approach is that it may inflate the type I error. However, such a possible inflation has not been mathematically quantified. In this paper the mathematical mechanism of this inflation is explored for two‐sample normal tests. A (conditional) type I error function based on normal data is derived. This function not only provides the quantification but also gives mathematical mechanisms of possible inflation in the type I error due to the sample size re‐estimation. Theoretically, based on their decision rules (certain upper and lower bounds), people can calculate this function and exactly visualize the changes in type I error. Computer simulations are performed to ensure the results. If there are no bounds for the adjustment, the inflation is evident. If proper adjusting rules are used, the inflation can be well controlled. In some cases the type I error can even be reduced. The trade‐off is to give up some ‘unrealistic power’. We investigated several scenarios in which the mechanisms to change the type I error are different. Our simulations show that similar results may apply to other distributions. Copyright © 2001 John Wiley & Sons, Ltd.
Positron emission tomography (PET) and other nuclear medicine modalities in staging gastrointestinal cancer
Authors: Bombardieri Emilio , Aliberti Gianluca , de Graaf Celine , Pauwels Ernest , Crippa Flavio
Published: August 2002

Gastrointestinal (GI) cancers account for the second highest number of new tumor cases and deaths per year in the United States and Western Europe. The most frequently involved sites are, in descending order, the colorectum, stomach, pancreas, liver, bile duct, and esophagus. The most common tumor type is adenocarcinoma. Among the epithelial cancers, great attention has recently been given to the tumors of neuroendocrine origin. These concepts are relevant because nuclear medicine imaging is based on visualization by means of a particular uptake of radiolabelled tracers in cancer cells that concentrate the radioactive signal. This signal is detected and reconstructed in planar or tomographic images. Different radiopharmaceuticals have been proposed for diagnostic application in oncology (such as radiolabelled monoclonal antibodies (MAbs), receptor tracers, and positron‐emitting radiopharmaceuticals), and they are currently used as tracers for tumor detection with different modalities and techniques. Most of these techniques demonstrate their clinical usefulness in the diagnosis of GI cancer. This work is not intended to be a comprehensive review of all the extensive experience and possibilities of nuclear medicine for the diagnosis of GI tumors; rather, it aims to summarize the current status of the most important approaches and their main indications in staging GI cancers. Semin. Surg. Oncol. 20:134–146, 2001. © 2001 Wiley‐Liss, Inc.
Minimally invasive techniques in breast cancer treatment
Authors: Singletary S. Eva
Published: August 2002

Breast conservation therapy has largely replaced mastectomy as the surgical treatment of choice for early‐stage breast cancer. As the sentinel lymph node mapping procedure, rather than routine axillary node dissection, becomes the standard of care, the next challenge is how to treat the primary tumor without surgery. Minimally invasive ablation of the primary tumor is possible with a variety of approaches; the goal is to either excise the tumor percutaneously or cool it (with cryotherapy) or heat it (with radiofrequency ablation (RFA), focused ultrasound, or laser interstitial therapy) sufficiently to cause complete cell death. These developing technologies may provide treatment options that are psychologically and cosmetically more acceptable to the patient than traditional therapies, but they need further investigation to prove that they are oncologically sound. This new frontier of surgery without scalpels will require surgeons to develop radiologic expertise and to acquire a basic understanding of molecular biology. Semin. Surg. Oncol. 20:246–250, 2001. © 2001 Wiley‐Liss, Inc.
Effects of aging on 5‐HT1A receptors and their functional response to 5‐HT1a agonist in the living brain: PET study with [carbonyl‐11C]WAY‐100635 in conscious monkeys
Authors: Tsukada Hideo , Kakiuchi Takeharu , Nishiyama Shingo , Ohba Hiroyuki , Harada Norihiro
Published: August 2002

Age‐related changes in the serotonin 5‐HT1A receptors in the living brains of conscious young (5.9 ± 1.8 years old) and aged (19.0 ± 3.3 years old) monkeys (Macaca mulatta) were evaluated by [carbonyl‐11C]WAY‐100635 and high‐resolution positron emission tomography (PET). The regional distribution pattern of [carbonyl‐11C]WAY‐100635 at 60–91 min postinjection was the highest in the cingulate gyrus and hippocampus, high in the frontal and temporal cortices, lower in the occipital cortex, striatum, thalamus, and raphe nuclei, and lowest in the cerebellum in both young and aged monkeys. Graphical Logan plot analysis with metabolite‐corrected plasma radioactivity as an input function into the brain was applied to evaluate 5‐HT1A receptor binding in vivo. Significant age‐related decreases in 5‐HT1A receptor binding were observed only in the frontal and temporal cortices. In the hippocampus, although 5‐HT1A receptor binding indicated no significant age‐related changes, it showed an inverse correlation with individual cortisol levels in plasma. When the 5‐HT1A receptor agonist 8‐OH‐DPAT was administered intravenously at a dose of 0.1, 0.3, or 1 mg/kg 30 min after tracer injection, binding of [carbonyl‐11C]WAY‐100635 was displaced in both age groups in a dose‐dependent manner. However, the degree of displacement was more marked in young than in aged monkeys. These observations demonstrated the usefulness of [carbonyl‐11C]WAY‐100635 as an indicator of the age‐related changes in cortical 5‐HT1A receptors measured noninvasively by PET. In addition, these observations suggested that the age‐related impairment of 5‐HT1A receptor responses to 8‐OH‐DPAT might be related to the reduced efficacy of antidepressant therapy in elderly patients with depression. Synapse 42:242–251, 2001. © 2001 Wiley‐Liss, Inc.
Optimal lateral stiffness design of tall buildings of mixed steel and concrete construction
Authors: Chan Chun‐Man
Published: August 2002

This paper presents an optimal sizing technique for the lateral stiffness design of tall steel and concrete buildings. The minimum structure cost design problem subject to lateral drift constraints is first mathematically formulated and then solved by a rigorously derived Optimality Criteria (OC) method. The emphasis is particularly placed on the practical applicability of the optimization technique in engineering practice. Once the structural form of the lateral load resisting system of a building is defined, the optimal steel and concrete element sizes are then sought while satisfying all serviceability lateral stiffness and practical sizing requirements. The effectiveness and practicality of the optimization technique is illustrated through an actual application to the preliminary design of an 88‐storey building in Hong Kong. When complete, the building will be 420 m tall and will become the tallest building in Hong Kong. Copyright © 2001 John Wiley & Sons, Ltd.
Chemistry and biology of phototropism‐regulating substances in higher plants
Authors: Yamamura Shosuke , Hasegawa Koji
Published: August 2002

Most people are familiar with the sight of a young seedling bending towards a window or the brightest source of light to which it is exposed. This directional growth response is known as phototropism, which is caused by a lateral growth‐promoting auxin in the bending organ (Cholodny‐Went theory, cited in high school textbook). Recently, however, Bruinsma et al., Weiler et al., and Hasegawa et al. independently found that the shaded half did not contain more auxin than the illuminated one. Instead it was found that the even distribution of auxin was accompanied by a lateral gradient of growth inhibiting substances during phototropic curvature (Bruinsma‐Hasegawa theory). We have isolated some photo‐induced growth inhibitory substances related to phototropism, benzoxazolinones from light‐grown maize shoots (Zea mays L.), raphanusanins from radish hypocotyl (Raphanus sativus var. hortensis f. gigantissimus M.), indolyacetonitrile from light‐grown shoots (Brassica oleacea L.), 8‐epixanthatin from sunflower hypocotyl (Helianthus annus L.), and quite recently uridine from oat coleoptile (Avena sativa L.). Chemical analyses have shown phototropic stimulations to cause curvature by inducing a local unequal distribution of growth‐inhibiting substances that antagonize auxin in its cell‐elongating activity. Finally, a model is presented for further studies on phototropism. © 2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:362–372, 2001