bluuebunny/crossref_metadata_2025_split huggingface dataset:
The bonding character of AlSO isomers in quartet excited states: Ab initio and density functional theory studies
Authors: Bu Yuxiang 
Published: August 2002

AbstractThe 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

AbstractThe 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

AbstractA 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

AbstractAn 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

AbstractGas 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

AbstractA 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

AbstractO‐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

AbstractA 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

AbstractImmobilized 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

AbstractThe 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

AbstractWe 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

AbstractNeonatal 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

AbstractDengue 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

AbstractWe 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

AbstractThis 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

AbstractThe 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

AbstractAnalytical 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

AbstractSample 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

AbstractGastrointestinal (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

AbstractBreast 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.