bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unified treatment for the evaluation of arbitrary multielectron multicenter molecular integrals over Slater‐type orbitals with noninteger principal quantum numbers
Authors: Özdoğan T. 
Published: March 2003

AbstractThe expansion formula has been presented for Slater‐type orbitals with noninteger principal quantum numbers (noninteger n‐STOs), which involves conventional STOs (integer n‐STOs) with the same center. By the use of this expansion formula, arbitrary multielectron multicenter molecular integrals over noninteger n‐STOs are expressed in terms of counterpart integrals over integer n‐STOs with a combined infinite series formula. The convergence of the method is tested for two‐center overlap, nuclear attraction, and two‐electron one‐center integrals, due to the scarcity of the literature, and fair uniform convergence and great numerical stability under wide changes in molecular parameters is achieved. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Systematic search of bounds for total π‐electron energy
Authors: Morales Daniel A. 
Published: March 2003

AbstractWe developed a systematic method to improve the known bounds for the total π‐electron energy E by designing a method based on the theory of symmetric polynomials and its inequalities. Additionally, the theory of symmetric polynomials applied to the problem of bounds for the total π‐electron energy suggests the definition of generalized arithmetic and geometric means, which can then be incorporated into Kober's theorem to obtain very sharp upper and lower bounds, better than those already known, in terms of the determinant of the adjacency matrix of the graph and/or higher‐order spectral moments. Having established a connection between the problem of the π‐electron energy and the theory of symmetric polynomials and its inequalities, we apply several other theorems from the theory of symmetric polynomials that allow us to obtain new explicit and implicit inequalities and to obtain implicit inequalities that in principle incorporate all spectral moments. In particular, we present an implicit inequality for the total π‐electron energy that is so sharp that it is for all practical purposes an equation for that energy. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Matrix‐assisted laser desorption/ionization detection of polymerase chain reaction products by utilizing the 5′‐3′ exonuclease activity of Thermus aquaticus DNA polymerase
Authors: Isola N. R. , Liu Z. , Allman S. L. , Taranenko N. I. , Kong Y. , Chen C. H. 
Published: March 2003

AbstractThe 5′‐3′ exonuclease activity of DNA polymerase was utilized in the polymerase chain reaction system to generate a specific signal concomitant with amplification. These signals were detected by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). This method obviates the need to perform extensive DNA purification of reaction products that is often necessary for detecting larger DNA molecules by mass spectrometry. Oligonucleotides complementary to the internal region of the amplicon are degraded by the 5′‐3′ exonuclease activity and the degradation products are analyzed by MALDI mass spectrometry. We refer to this assay as the Exo‐taq assay or probe degradation assay. This method should be amenable to automation. Copyright © 2003 John Wiley & Sons, Ltd.
Quantification of [Dmt1]DALDA in ovine plasma by on‐line liquid chromatography/quadrupole time‐of‐flight mass spectrometry
Authors: Wan Haibao , Desiderio Dominic M. 
Published: March 2003

AbstractThe synthetic peptide [Dmt1]DALDA (Dmt‐D‐Arg‐Phe‐Lys‐NH2; Dmt = 2′,6′‐dimethyltyrosine; ‘super‐DALDA’) is a mu opioid‐receptor agonist. On‐line liquid chromatography/quadrupole time‐of‐flight mass spectrometry and the corresponding stable isotope‐incorporated synthetic peptide internal standard were used to quantify [Dmt1]DALDA that had been extracted from ovine plasma samples. The [M+2H]2+ ion was used to construct the calibration curve, and the product ion was used for verification of the peptide. The detection sensitivity for the [Dmt1]DALDA [M+2H]2+ ion was 12.5 fmol and 50 fmol for the m/z 432.3 product ion. The concentration profile of [Dmt1]DALDA was determined from a set of ovine plasma samples. The molecular specificity of the peptide quantification was confirmed by tandem mass spectrometry (MS/MS). Copyright © 2003 John Wiley & Sons, Ltd.
Accurate mass measurement at enhanced mass‐resolution on a triple quadrupole mass‐spectrometer for the identification of a reaction impurity and collisionally‐induced fragment ions of cabergoline
Authors: Paul Gary , Winnik Witold , Hughes Nicola , Schweingruber Hans , Heller Rexford , Schoen Alan 
Published: March 2003

AbstractIn this study, accurate mass measurements were made by electrospray ionization (ESI) on a triple quadrupole mass spectrometer operating in enhanced mass‐resolution mode (peak width = 0.1 u FWMH), to give qualitative information relating to the pharmaceutical, cabergoline. Accurate mass determinations by ESI‐MS were performed on a protonated impurity formed during cabergoline storage. The accurate mass measurement resulted in only one proposed elemental composition for the impurity, using reasonable elemental limits and mass tolerance for the calculation. This information was sufficient to propose a structure for the impurity where ESI‐MS/MS proved consistent. The difference between the accurate mass measurement and the exact mass calculated for the proposed structure was 0.8 mmu, with a standard deviation of 0.7 mmu for replicate accurate mass determinations. Accurate mass determinations in ESI‐MS/MS provided information on cabergoline fragment ions formed through collisionally‐induced dissociation. Since the potential formation of isobaric ions exists for two major cabergoline fragment ions, accurate mass measurement allowed for the determination of the most probable fragment ion structures. The differences between the accurate mass measurements and exact masses calculated for the proposed fragment ions were 1.9 and 2.1 mmu, with standard deviations of 0.4 and 0.8 mmu, respectively, for replicate determinations. Copyright © 2003 John Wiley & Sons, Ltd.
Nanotube Membrane Sensors: Resistive Sensing and Ion Channel Mimetics
Authors: Wirtz M. , Martin C. R. 
Published: March 2003

AbstractNanotubule membranes are utilized for sensing applications and ion channel mimetics. The nanotubule membranes are composed of either gold or alumina. The gold nanotubule membranes are prepared via electroless deposition of Au on to the pore walls of a polycarbonate membrane, ie, the pores act as templates for the nanotubes. These membranes are a new class of molecular sieves and can be used to separate small molecules on the basis of molecular size. In addition, the use of these membranes in new approaches to electrochemical sensing is discussed. In this case, a current is forced through the nanotubes, and analyte molecules present in a contacting solution phase modulate the value of this transmembrane current. We further discuss synthetic micropore and nanotube membranes that mimic the function of a ligand‐gated ion channel, ie, these membranes can be switched from an ‘off’ state (no or low ion current through the membrane) to an ‘on’ state (higher ion current) in response to the presence of a chemical stimulus, eg, drug or surfactant. Ion channel mimics are based on both modified Au nanotube and microporous alumina membranes.First published online: July 12, 2002.
Microstructural and physicochemical study of the buried Fe/AlGaAs(100) interface by transmission electron microscopy and x‐ray emission spectroscopy
Authors: Monteverde F. , Jonnard P. , Harel S. , Michel A. , Eymery J. P. 
Published: March 2003

AbstractAmong the magnetic metal/semiconductor contacts, the Fe/GaAs system has been widely studied owing to its potential applications in electronic devices. In contrast, there are not many studies concerning the Fe/AlxGa1−xAs contact, and in particular there are no reports concerning the changes induced in the interfacial zone by the presence of Al. In this work, thin polycrystalline iron films were deposited by ion beam sputtering at room temperature on a 300 nm thick Al0.25Ga0.75As layer grown by molecular beam epitaxy onto GaAs(001). X‐ray diffraction analysis showed that the iron films are polycrystalline, and indications of a (002) texture of the film were observed. The fine scale analysis of the interface was achieved by high‐resolution transmission electron microscopy (HRTEM) observations, the results of which are compared with the physicochemical information obtained from electron‐induced x‐ray emission spectroscopy, by analysing the Al 3p valence states at the Fe/AlxGa1−xAs interface. The HRTEM experiments on cross‐section samples indicate that the interfacial zone between iron and AlGaAs is limited to <1.5 nm in thickness. X‐ray emission spectroscopy showed the presence of Al atoms in an FeAl‐like environment at the interface, and the existence of wrong bonds and point defects. The estimated width of the perturbed interface (2.0 ± 0.5 nm) is in agreement with the HRTEM results. Copyright © 2003 John Wiley & Sons, Ltd.
Chemical maps of patterned samples by microline‐imaging laser‐induced plasma spectrometry
Authors: Cabalín L. M. , Mateo M. P. , Laserna J. J. 
Published: March 2003

AbstractThe potential of a microline‐imaging laser‐induced plasma spectrometry (LIPS) system for surface and depth analysis of heterogeneous solid samples in air at atmospheric pressure has been demonstrated. A pulsed Nd : YAG laser beam operating at 532 nm, with a homogeneous energy distribution (flat top laser), was used to generate a microline plasma on the sample surface. Subsequent light from the microline plasma was resolved spectrally and spatially and detected with an imaging spectrograph and an intensified charged‐coupled device detector. A patterned metal sample was chosen as the most appropriate for this study. Three‐dimensional chemical maps of Ni and Cu from the edge connectors of a printed circuit board have been obtained. With this experimental configuration, the lateral resolution (limited by crater width) was 42 µm and the spatial resolution along the spectrometer slit was 17.4 µm. The results illustrate the capability of microline imaging for fast mapping of large‐area samples and for depth profiling purposes. Copyright © 2003 John Wiley & Sons, Ltd.
Summary of ISO/TC 201 Standard XI. ISO 17974:2002—Surface chemical analysis—High‐resolution Auger electron spectrometers—Calibration of energy scales for elemental and chemical‐state analysis
Authors: Seah M. P. 
Published: March 2003

AbstractThis International Standard specifies a method for calibrating the kinetic energy scales of Auger electron spectrometers for elemental and chemical‐state analysis at surfaces. It is only applicable to instruments that incorporate an ion gun for sputter cleaning. This International Standard further specifies a method to establish a calibration schedule, to test for the kinetic energy scale linearity at one intermediate energy, to confirm the uncertainty of the scale calibration at one low and one high kinetic energy value, to correct for small drifts of that scale and to define the expanded uncertainty of the calibration of the kinetic energy scale for a confidence level of 95%. This uncertainty includes contributions for behaviours observed in interlaboratory studies but does not cover all of the defects that could occur. This International Standard is not applicable to instruments with kinetic energy scale errors that are significantly non‐linear with energy, to instruments operated at relative resolutions poorer than 0.2% in the constant ΔE/E mode or poorer than 1.5 eV in the constant ΔE mode, to instruments requiring tolerance limits of ±0.05 eV or less or to instruments equipped with an electron gun that cannot be operated in the energy range 5–10 keV. This standard does not provide a full calibration check, which would confirm the energy measured at each addressable point on the energy scale and should be performed according to the manufacturer's recommended procedures. Crown Copyright © 2003. Published by John Wiley & Sons, Ltd.
Degradation of plasticized PVC for biomedical disposable device under soft x‐ray irradiation
Authors: Manfredini M. , Atzei D. , Elsener B. , Marchetti A. , Rossi A. 
Published: March 2003

AbstractPlasticized poly(vinyl chloride) (PVC) used for biomedical disposable devices was studied in the non‐sterilized state after different exposure times to soft x‐ray irradiation in a commercial photoelectron spectrometer (Al Kα, 15 kV/300 W; Mg Kα, 12 kV/240 W) by XPS surface analysis. The detailed spectra of C 1s, Cl 2p and O 1s have been recorded and processed. Irradiation with soft x‐rays induces a clear decrease of the total Cl 2p intensity, an increase of total C 1s intensity and a doubling of the O 1s intensity after 45 min of irradiation with Al Kα (300 W). Irradiation with Mg Kα (240 W) is slightly less damaging. These results can be interpreted with the classical PVC degradation model, e.g. bond cleavage with the formation of HCl gas, although the Cl 2p high‐resolution spectra reveal the formation of an additional side‐product, probably CaCl2. For further studies of plasticized PVC using XPS surface analysis it can be concluded that a complete analysis of a polymer sample should not take >10 min of x‐ray exposure in order to avoid notable polymer degradation. Copyright © 2003 John Wiley & Sons, Ltd.
Population pharmacokinetics/pharmacodynamics relationships of an anticancer drug
Authors: Ané Cécile , Concordet Didier 
Published: March 2003

AbstractThis paper proposes a method for studying the toxicity of an anticancer drug with a delayed effect. The goal is to predict a dosage regimen with controlled toxicity. To this end, a semi‐physiological model is used. A limit of toxicity is demonstrated, which is intrinsic to the model. It reduces the effect of high drug concentrations. This limit explains the mixed behaviour of the drug: time‐dependence and concentration‐dependence, according to the dose actually administered. A population analysis is performed to estimate the parameters of the model, and to predict a safe dosage regimen. Copyright © 2003 John Wiley & Sons, Ltd.
Multilevel webs stretched across time: retroactive and proactive inter‐influences
Authors: Hardy Christine 
Published: March 2003

AbstractSemantic Fields Theory (SFT) poses that the mind works through semantic network dynamics (i.e. knowledge acquisition) and specific semantic parameters. Consequently, the mind is intrinsically non‐dependent on space‐time and yet its dynamics crisscross it. Personal and collective anticipations and projections create a Multilevel Web (semantic forces coupled with their environment) which has the specificity of being conjointly tied to the present and future time of implementation. The resulting system, or Sygma‐Web, instantiates proactive and retroactive properties, such as informing both the project's present context and its future context, and the trajectory in between. Using as an example the development of a new product, I argue that classical causality accounts for only a local effect of the future product (once released) on the future market. By contrast, the Sygma‐Web formalization posits that collective expectations about a future shift in the market and consumer behaviours are specifically the force that changes the market in the direction of the expectations. Copyright © 2003 John Wiley & Sons, Ltd.
Economy of communion: systemic factors in the rise of a new entrepreneurship
Authors: Linard Keith T. 
Published: March 2003

AbstractThe Economy of Communion is an experience of social economy sprung from the praxis of the Focolare Movement, an ecumenical and inter‐religious organization with roots in the Catholic Church. This radical social phenomenon is played out in intersecting local and global networks. Businesses operating within the paradigm form communications and ‘thought networks’ spanning the globe, but function typically within local markets. Within a decade this ideal has spread to 100 countries, attracted some 800 firms, generated almost 100 academic theses, and been accorded significant international recognition through UNESCO and the Council of Europe and through the award of various honorary doctorates by prestigious universities. This paper examines the systemic philosophical, cultural and organizational factors associated with its dissemination. Copyright © 2003 John Wiley & Sons, Ltd.
Nitric oxide modulates striatal neuronal activity via soluble guanylyl cyclase: An in vivo microiontophoretic study in rats
Authors: Di Giovanni Giuseppe , Ferraro Giuseppe , Sardo Pierangelo , Galati Salvatore , Esposito Ennio , La Grutta Vittorio 
Published: March 2003

AbstractIt is now well established that nitric oxide (NO) acts as a neuromodulator in the central nervous system. To assess the role of NO in modulating striatal activity, single‐unit recording was combined with iontophoresis to study presumed spiny projection neurons in urethane‐anesthetized male rats. Striatal neurons recorded were essentially quiescent and were therefore activated to fire by the iontophoretic administration of glutamate, pulsed in cycles of 30 sec on and 40 sec off. In this study, iontophoresis of 3‐morpholinosydnonimine hydrochloride (SIN 1), a nitric oxide donor, produced reproducible, current‐dependent inhibition of glutamate‐induced excitation in 12 of 15 striatal neurons, reaching its maximal inhibitory effect (76.2 ± 5.6% below baseline) during the application of a 100 nA current. Conversely, microiontophoretic application of N‐ω‐nitro‐L‐arginine methyl ester (L‐NAME), an inhibitor of nitric oxide synthase, produced clear and reproducible excitation of glutamate evoked firing in 7 of 10 cells (51.4 ± 2.3%, at 100 nA). To evaluate the involvement of cyclic guanosine monophosphate (cGMP) in the electrophysiological effects produced by the NO donor, the effects of methylene blue, an inhibitor of guanylyl cyclase, on the responses of nine neurons to SIN 1 were tested. In six of nine neurons the effect of SIN 1 was significantly reduced during continuous iontophoretic administration (50 nA) of methylene blue. Taken together, these data show that NO modulates the striatal network and that inhibitory control of the output neurons is involved in this effect. These results also suggest that the effects of nitric oxide on striatal neurons are partially mediated via cGMP. Synapse 48:100–107, 2003. © 2003 Wiley‐Liss, Inc.
Oral toxicity of the cyanobacterial toxin cylindrospermopsin in male Swiss albino mice: Determination of no observed adverse effect level for deriving a drinking water guideline value
Authors: Humpage A. R. , Falconer I. R. 
Published: March 2003

AbstractThe cyanobacterial toxin cylindrospermopsin (CYN) is a frequent contaminant of freshwaters throughout the world, including those that are sources of drinking water. The first cases of human poisoning attributed to this toxin occurred from a treated drinking water supply in Queensland, Australia, in 1979. The toxin causes extensive damage to the liver, kidneys, spleen, heart, and other organs. It is known to be a potent protein synthesis inhibitor, but there is mounting evidence for genotoxicity and that it metabolizes to even more toxic forms. As part of a risk assessment process leading to a guideline for a safe drinking water level for this toxin, we performed a series of experiments to determine a no‐observed‐adverse‐effect level (NOAEL) for this toxin. In the first trial male mice were exposed to CYN‐containing cyanobacterial extract in their drinking water (0–657 μg CYN kg−1 day−1) for 10 weeks. In the second trial mice received purified CYN by daily gavage (0–240 μg CYN kg−1 day−1) for 11 weeks. Body and organ weights were recorded; urine, serum, and hematology analyses were performed; and histopathological examination of tissues was carried out. Body weights were significantly increased at low doses (30 and 60 μg kg−1 day−1) and decreased at high doses (432 and 657 μg kg−1 day−1). Liver and kidney weights were significantly increased at doses of 240 μg kg−1 day−1 and 60 μg kg−1 day−1, respectively. Serum bilirubin levels were significantly increased and bile acids significantly decreased at doses of 216 μg kg day−1 and greater. Urine total protein was significantly decreased at doses above 60 μg kg−1 day−1. The kidney appeared to be the more sensitive organ to this toxin. If it is assumed that increased organ weights and changes in functional capacity are responses to an underlying toxic effect, then the NOAEL based on this data is 30 μg kg−1 day−1, which, with standard calculations and uncertainty factors, provides a proposed guideline safety value of 1 μg/L in drinking water. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 94–103, 2003.
Influence of body size and gender on valve movement responses of a freshwater bivalve to uranium
Authors: Markich Scott J. 
Published: March 2003

AbstractBody size, age, and gender (male or female) are important variables influencing many aspects of the ecology, physiology, and survival of animals. However, no data are available on the influence of these variables on bivalves exposed to sublethal metal concentrations. This study tested whether the valve movement responses (measured in terms of the duration or frequency of valve opening) of the Australian tropical freshwater unionoid bivalve, Velesunio angasi, exposed to sublethal uranium (U) concentrations in a standard synthetic water (pH, 6.0; hardness and alkalinity, 4 mg/L as CaCO3) were influenced by body size (shell length, shell breadth, or dry tissue weight), age, and/or gender. The valve movement responses of V. angasi to U were independent of gender; the sensitivity of males to U was not significantly (p > 0.05) different from that of females. In contrast, the valve movement responses of V. angasi to U were size‐ and age‐dependent; smaller and younger individuals (median shell length = 36.8 mm; median age = 0.7 years) were 22% more sensitive (p ≤ 0.05) than larger and older individuals (median shell length = 61.3 mm; median age = 14 years). By correcting for differences in body size, age, and/or gender among individuals, using multiple linear regression analyses, the mean variability in valve movement responses was reduced by 81%. Consequently, errors (95% confidence limits) associated with valve movement response (EC50) values were substantially reduced (75%). Hence, the ability to demonstrate statistically significant (p ≤ 0.05) differences in valve movement responses between U exposure concentrations was enhanced. This, in turn, may permit better estimates of the risk of the effects of U exposures to bivalve populations. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 126–136, 2003