bluuebunny/crossref_metadata_2025 huggingface dataset:
High‐field electrical properties under AC voltage application in acetophenone‐coated LDPE film
Authors: Mitsumoto Shin'ichi , Nagao Masayuki , Fukuma Masumi , Hozumi Naohiro
Published: December 2002

This paper deals with the effects of acetophenone coating on dielectric properties such as tan δ and capacitance and on space charge formation up to electrical breakdown under AC voltage application in low‐density polyethylene (LDPE) film. The existence of acetophenone at the electrical interface enhances tan δ. tan δ in acetophenone‐coated specimens increased with electric field and decreased with the frequency in the high‐field and high‐temperature region. AC breakdown test revealed that the electric strength in noncoated specimens was higher than in acetophenone‐coated specimens, and that the electric strength also decreased with temperature. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(3): 1–7, 2003; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.10086
Development of a new adaptive LQG system generator for high‐speed damping control techniques of power system oscillation
Authors: Michigami Tsutomu , Terasaki Masaru , Sasazima Nobuyoshi , Hayashi Kunitake , Okamoto Takashi
Published: December 2002

With the advent of interconnection of large‐scale electric power systems, many new dynamics power system problems have emerged, which include low‐frequency intersystem oscillations and many others. To date, most major generators in trunk electric power systems in Japan are equipped with supplementary excitation control, commonly referred to as the conventional single and two input PSS. However, low‐frequency oscillations still occur. It is difficult for these conventional PSS to improve the additional damping of power system oscillation, because of the hardware and design of fixed PSS control constants from a one‐machine infinite‐bus model. It has therefore become necessary to develop a new adaptive LQG system generator. This paper explains the development of the new adaptive LQG system and the simulation of low‐frequency and local mode oscillation for this new adaptive LQG system. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(3): 30–40, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10109
A study of the occurrence mechanism for undershoot of logic signal
Authors: Toyoda Keiji
Published: December 2002

Waveform distortion of logic signal caused by accelerated clock speed and increased implementation density causes nonlinear output and has been responsible for behavioral problems in electronic systems, including the overshoot type, hysteresis type, and undershoot type of transient waveform distortion. Deep undershoot could cause latchup of CMOS logic ICs, data destruction in DRAM, and pulse splitting in TTL ICs. Undershoot of logic signals is discussed in terms of both transient phenomena (time domain) and filter theory (frequency domain). Variation of the resistance R caused by output circuit impedance variation creates time domain variations in such quantities as the damping constant α and damping coefficient ζ, while variation of resistance R creates Q variation in the frequency domain.

This paper describes a mechanism by which undershoot occurs when parasitic series resonance circuits are formed on the load side of the driving device and the damping coefficient ζ varies time‐sequentially in totem‐pole or complementary circuits. PSpice simulation suggests that undershoot can be reduced by controlling the phase of the punchthrough current. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(3): 41–48, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10141
Peak broadening in microchip electrophoresis: A discussion of the theoretical background
Authors: Gaš Bohuslav , Kenndler Ernst
Published: December 2002

A review on peak (band, zone) broadening in electromigration separation methods is presented, mainly covering articles published between the begining of 2000 and middle of 2002. Most attention is drawn to work dealing with microchip electrophoresis performed in micrototal analysis systems (μTAS) or the lab‐on‐a‐chip, but many of the results are significant for capillary zone electrophoresis in general. The paper reviews the theoretical background of the peak dispersion due to the geometry of the separation channel, the transversal nonhomogeneity of the electroosmootic flow, and electromigration dispersion (sample overload) connected with the occurrence of the system zones (system peaks, system eigenpeaks).
Recent advances in capillary isoelectric focusing: 1997–2001
Authors: Shimura Kiyohito
Published: December 2002

The methodological developments in the field of capillary isoelectric focusing (CIEF) published between 1997–2001 are reviewed as a continuation of the previous review by Rodriguez‐Diaz et al. (Electrophoresis 1997, 18, 2134–2144). The applications are summarized and the progress in CIEF technologies, including experimental setup with coated and uncoated capillaries, remedies for the presence of salts in samples, additives to reduce precipitation of samples during the focusing process, calibration of the pH gradients, issues of reproducibility, carrier ampholyte‐free CIEF, and a computer simulation of focusing process are discussed. Developments of IEF separations in fabricated microchannels and the advances in detection schemes, i.e., imaging, fluorescence and chemiluminescence, are summarized. The progress in micropreparation was noted, and the massive works for two‐dimensional separations are described for the coupling with size‐exclusion chromatography and mass spectrometry, in which the developments aimed at proteomics are discussed separately. The applications for the detection of noncovalent complexes and the separations of microorganisms are reviewed.
Recent advances in nonaqueous capillary electrophoresis
Authors: Riekkola Marja‐Liisa
Published: December 2002

Nonaqueous capillary electrophoresis is undergoing rapid development. The scope of the investigations has clearly expanded, covering both basic studies and analytical applications. This review provides a comprehensive overview at the current status of the technique. Special attention is given to theoretical, methodological, and technical challenges, and the achievements of capillary electrophoresis in nonaqueous media are demonstrated with reference to recent applications.
Recent advances and trends in capillary electrophoresis of inorganic ions
Authors: Timerbaev Andrei R.
Published: December 2002

Capillary electrophoresis (CE) continues its invasion into the domain of inorganic analysis. This review summarizes the progress and significant developments of CE of inorganic ions over the first two years of the new century. As manifested by the substantial number of published articles, this field is still witnessing a growing activity of many separation scientists. To provide an in‐depth treatment of fundamental and methodological aspects of inorganic ion analysis by CE, an extensive fraction of the relevant literature is covered whereas only most innovative application reports are briefly considered. Most of the recent advancements have focused on CE system modernization designed to improve a limited detection sensitivity, which still remains a major obstacle to overcome in order to ensure the method's wider practical acceptance. Attention is also given to how and in which directions the future research could be performed to implement CE in routine inorganic analysis.
Micellar electrokinetic chromatography: Current developments and future
Authors: Molina Manuel , Silva Manuel
Published: December 2002

This review highlights recent methodological and instrumental advances in micellar electrokinetic chromatography (MEKC). Enhancements in sensitivity and selectivity of the technique through the use of on‐line preconcentration approaches (stacking and sweeping) and nonconventional pseudostationary phases, namely nonionic and zwitterionic surfactants, mixed micelles and polymers, are discussed in detail. Laser‐induced fluorescence and mass spectrometry, as alternatives to UV‐absorption detection, have been covered to evaluate their advantages and limitations when applied to analysis in an MEKC format. Some thoughts on future directions in this area such as in‐capillary reactions, coated capillaries and MEKC on microchips are also presented.
Recent progress in adsorbed stationary phases for capillary electrochromatography
Authors: Liu Zhen , Wu Ren'an , Zou Hanfa
Published: December 2002

This review surveys the recent progress in the adsorbed stationary phases for capillary electrochromatography (CEC). Adsorption‐based methods for preparation of stationary phase are novel approaches in CEC, which allow rapid and facile preparing stationary phases with desirable selectivity onto an open‐tubular fused‐silica capillary, a bare‐silica or ion‐exchange packed column or a monolithic silica or polymer column. A variety of adsorbing agents have been developed as adsorbed stationary phases, including ionic long‐chain surfactant, protein, peptide, amino acid, charged cyclodextrin (CD), basic compound, aliphatic ionene, and ion‐exchange latex particle. The adsorbed stationary phases have been applied to separation of neutral, basic and acidic organic compounds, inorganic anions and enantiomers. They have also been applied to on‐line sample concentration, fast separation and study of the competitive binding of enantiomers with protein.
Enantiomer migration order in chiral capillary electrophoresis
Authors: Chankvetadze Bezhan
Published: December 2002

Enantiomer migration order (EMO) in chiral capillary electrophoresis (CE) represents a challenging issue, referred to in less than 20% of the articles on CE enantioseparations. This review articie will (i) illustrate the actuality of the topic, (ii) discuss some technical problems related to EMO in CE enantioseparations, (iii) examine the principal differences between CE and other separation techniques from the viewpoint of enantiomer elution order, (iv) demonstrate the potential for a designed reversal of EMO in CE, and (v) emphasize the importance of studying EMO for better understanding of chiral CE as well as its more effective application. Along with CE, the results obtained by other instrumental techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), X‐ray crystallography, as well as molecular modeling calculations will be shortly discussed. Rather than referring to all published examples of the opposite migration order of enantiomers in CE, the emphasis will be on general aspects. Recently, the reversal of the EMO was described in detail in a book chapter (Chankvetadze, B., Capillary Electrophoresis in Chiral Analysis, Wiley & Sons, Chichester, UK 1997, Chapter 12) as well as in three review articles [1, 3, 4].
Chiral capillary electrophoresis‐mass spectrometry: Modes and applications
Authors: Shamsi Shahab A.
Published: December 2002

A review is presented to highlight several approaches for coupling capillary electrophoresis (CE) and electrospray ionization‐mass spectrometry (ESI‐MS) for analysis of chiral compounds. A short discussion of commercially available CE‐MS instruments and interface design is followed by a detail review on various modes of chiral CE‐MS. In general, for each CE‐MS mode, the capabilities, applications and limitations for chiral analysis have been pointed out. The first mode, chiral capillary zone electrophoresis‐mass spectrometry (CZE‐MS) in which neutral derivatized cyclodextrins (CDs) are used is possible using either column coupling with voltage switching or a partial‐filling technique (PFT). However, some applications of direct coupling of CZE‐MS mode are also reported. The second mode is a chiral electrokinetic chromatography‐mass spectrometry (EKC‐MS) in which a charged chiral selector such as a sulfated β‐CD or a vancomycin could be conveniently employed. This is because these chiral selectors have a significantly higher countercurrent electrophoretic mobility which prevents the entrance of these selectors into the mass spectrometer. The combination of counter‐migration and PFT demonstrates that this synergism could be successfully applied to chiral analysis of a broader range of compounds. It is well‐known that the on‐line coupling of micellar electrokinetic chromatography to mass spectrometry (MEKC‐MS) is problematic because the high surface activity and nonvolatile nature of conventional surfactant molecules lower the electrospray ionization efficiency. However, a recent report demonstrates that this hyphenation is now possible with the use of molecular micelles. Various MEKC‐ESI‐MS parameters that can be used to optimize both chiral resolution and ESI response are discussed. Finally, two recent examples that demonstrate the feasibility of using either open‐tubular or packed chiral CEC with MS are reviewed. This survey will attempt to cover the state‐of‐the‐art on various modes of CE‐MS from 1998 up to 2002.
Evaluation of a potential epigenetic biomarker by quantitative methyl‐single nucleotide polymorphism analysis
Authors: Uhlmann Karen , Brinckmann Anja , Toliat Mohammad R. , Ritter Heide , Nürnberg Peter
Published: December 2002

Tumorigenesis is characterized by alterations of methylation profiles including loss and gain of 5‐methylcytosine. Recently, we identified a single CpG, which seemed to be consistently hypomethylated in pilocytic astrocytomas but not in other gliomas. To evaluate its applicability as a biomarker, we examined its methylation status in a large panel of gliomas (n = 97). Methylation‐dependent DNA sequence variation may be considered a kind of single nucleotide polymorphism (methylSNP). MethylSNPs can be easily converted into common SNPs of the C/T type by sodium bisulfite treatment of the DNA and afterwards subjected to conventional SNP typing. We adapted SnaPshot™ and Pyrosequencing™ to determine the methylation of our test CpG in a quantitative manner. The adapted methods, called SNaPmeth and PyroMeth, respectively, gave nearly identical results, however data obtained with PyroMeth showed less scattering. Furthermore, the integrated software for allele frequency determination from Pyrosequencing could be used directly for data analysis while SnaPmeth data had to be exported and processed manually. Although data did not confirm our previous result of a preferential hypomethylation of the tested CpG in pilocytic astrocytomas, we consider quantitative methylSNP analysis by SNaPmeth or PyroMeth a favorable alternative to existing high‐throughput methylation assays. It combines single CpG analysis with accurate quantitation and is amenable to high throughput.
Complete mitochondrial DNA sequence of a tadpole shrimp (Triops cancriformis) and analysis of museum samples
Authors: Umetsu Kazuo , Iwabuchi Naruki , Yuasa Isao , Saitou Naruya , Clark Paul F. , Boxshall Geoff , Osawa Motoki , Igarashi Keiji
Published: December 2002

The complete mitochondrial DNA (mtNDA) of the tadpole shrimp Triops cancriformis was sequenced. The sequence consisted of 15 101 bp with an A+T content of 69%. Its gene arrangement was identical with those sequences of the water flea (Daphnia pulex) and giant tiger prawn (Penaeus monodon), whereas it differed from that of the brine shrimp (Artemia franciscana) in the arrangement of its genes for tRNAs. Phylogenetic analysis revealed T. cancriformis to be more closely related to the water flea than to the brine shrimp and giant tiger prawn. We also compared the 16S rRNA sequences of five formalin‐fixed tadpole shrimps that had been collected in five different locations and stored in a museum. The sequence divergence was in the range of 0–1.51%, suggesting that those samples were closely related to each other.
BRCA1 mutation screening using restriction endonuclase fingerprinting‐single‐strand conformation polymorphism in an automated capillary electrophoresis system
Authors: Kringen Pedro , Egedal Sidsel , Pedersen Jan C. , Harbitz Thorstein B. , Tveit Kjell M. , Berg Kåre , Børresen‐Dale Anne‐Lise , Andersen Tone I.
Published: December 2002

Efficient mutation scanning techniques are needed for the rapid detection of novel disease‐associated mutations and rare‐sequence variants of putative importance. The large size of the breast cancer 1 gene (BRCA1) and the many mutations found throughout its entire coding sequence make screening for mutations in this gene particularly challenging. We have developed a method for screening exon 11 of the BRCA1 gene based on restriction enzyme digestion of fluorescence‐labeled polymerase chain reaction (PCR) products followed by single‐strand conformation polymorphism (SSCP) using an automated capillary electrophoresis system, denoted capillary restriction endonuclease fingerprinting (REF)‐SSCP electrophoresis. Using this strategy on a control set of samples, we were able to detect 17 of 18 known sequence alterations. The method was then applied to screen 73 Norwegian females with family histories of breast and/or ovarian cancer. A total of 172 sequence alterations were detected, including substitutions, insertions, and deletions. One novel substitution of unknown function was identified. Sequencing of all samples negative in the capillary REF‐SSCP system gave no additional mutations confirming the high sensitivity of the described methodology. Capillary REF‐SSCP electrophoresis appeared as a technically convenient technique, requiring amplification of fewer PCR fragments than traditional SSCP. The novel strategy allows high‐throughput mutation scanning without radioactive labeling and polyacrylamide gel electrophoresis (PAGE).
Proteomic analysis of rat brain tissue: Comparison of protocols for two‐dimensional gel electrophoresis analysis based on different solubilizing agents
Authors: Carboni Lucia , Piubelli Chiara , Righetti Pier Giorgio , Jansson Birger , Domenici Enrico
Published: December 2002

The present study reports a comparison of recently described solubilizing methods, to set up a simple protocol for obtaining two‐dimensional (2‐D) gel electrophoresis maps of brain tissue. Different protocols were used for preparing rat brain homogenates and the resulting maps were compared by image analysis. Three different detergents, two delipidation methods, and introduction of a fractionation step based on different protein solubility in surfactants, were evaluated. When using efficient zwitterionic detergents (3‐[(3‐cholamidopropyl)dimethylamino]‐1‐propanesulfonate, CHAPS; amidosulfobetaine 14, ASB‐14), the patterns obtained by direct loading of total extracts were qualitatively overlapping with patterns obtained from fractionated samples. In contrast, a weaker nonionic agent (Nonidet P‐40, NP‐40) produced a different protein pattern in the collected fractions. Delipidation did not improve the results for all the different extraction methods. Immunoblots performed with antibodies recognizing cytosolic and membrane‐spanning proteins, which were detected as nondegraded spots, showed that membrane proteins with intermediate molecular mass could be recovered. We suggest, as a simple and efficient method for preparing rat brain maps, the homogenization in a solution containing an efficient zwitterionic surfactant, which allows to solubilize cytosolic and membrane proteins in a single step. Alternatively, a fractionation can be carried out on samples homogenized by a weak solubilizing agent, a more labor‐intensive effort resulting in a larger number of proteins on two maps.
Proteome analysis of human liver tumor tissue by two‐dimensional gel electrophoresis and matrixassisted laser desorption/ionization‐mass spectrometry for identification of disease‐related proteins
Authors: Kim Jina , Kim Soon H. , Lee Seung U. , Ha Geun H. , Kang Deok G. , Ha Na‐Young , Ahn Jin S. , Cho Hey Y. , Kang Sung‐Jo , Lee Young‐Joon , Hong Soon C. , Ha Woo S. , Bae Jong M. , Lee Chang‐Won , Kim Jae W.
Published: December 2002

Hepatocellular carcinoma (HCC) is a common malignancy worldwide and is a leading cause of death. To contribute to the development and improvement of molecular markers for diagnostics and prognostics and of therapeutic targets for the disease, we have largely expanded the currently available human liver tissue maps and studied the differential expression of proteins in normal and cancer tissues. Reference two‐dimensional electrophoresis (2‐DE) maps of human liver tumor tissue include labeled 2‐DE images for total homogenate and soluble fraction separated on pH 3–10 gels, and also images for soluble fraction separated on pH 4–7 and pH 6–9 gels for a more detailed map. Proteins were separated in the first dimension by isoelectric focusing on immobilized pH gradient (IPG) strips, and by 7.5–17.5% gradient sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) gels in the second dimension. Protein identification was done by peptide mass fingerprinting with delayed extraction‐matrix assisted laser desorption/ionization‐time of flight‐mass spectrometry (DE‐MALDI‐TOF‐MS). In total, 212 protein spots (117 spots in pH 4–7 map and 95 spots in pH 6–9) corresponding to 127 different polypeptide chains were identified. In the next step, we analyzed the differential protein expression of liver tumor samples, to find out candidates for liver cancer‐associated proteins. Matched pairs of tissues from 11 liver cancer patients were analyzed for their 2‐DE profiles. Protein expression was comparatively analyzed by use of image analysis software. Proteins whose expression levels were different by more than three‐fold in at least 30% (four) of the patients were further analyzed. Numbers of protein spots overexpressed or underexpressed in tumor tissues as compared with nontumorous regions were 9 and 28, respectively. Among these 37 spots, 1 overexpressed and 15 underexpressed spots, corresponding to 11 proteins, were identified. The physiological significance of the differential expressions is discussed.
Comparison of ethanol‐soluble proteins from different rye (Secale cereale) varieties by two‐dimensional electrophoresis
Authors: Radzikowski Louise , Nešić Ljiljana , Hansen Hanne Boskov , Jacobsen Susanne , Søndergaard Ib
Published: December 2002

The major storage proteins from six rye varieties, grown under the same conditions in 1997 and 1998 in Rønhave, Denmark, were analyzed by two‐dimensional (2‐D) polyacrylamide gel electrophoresis. The proteins were extracted from ground rye kernels with 70% ethanol and separated by 2‐D electrophoresis. The gels were scanned, compared using ImageMaster® software and the data sets were analyzed by principal component analysis (PCA) using THE UNSCRAMBLER software. Afterwards MATLAB was used to make a cluster analysis of the varieties based on PCA. The analysis of the gels showed, that the protein patterns (number of different proteins and their isoelectric points and molecular weights) from the six rye varieties were different. Based on the presence of unique cultivar‐specific spots it was possible to differentiate between all six varieties if the two harvest years were investigated separately. When the results were combined from the two years five varieties could be differentiated. The results from the PCA confirmed the finding of the unique spots and cluster analysis was made in order to illustrate the results. The combination of the results from 2‐D electrophoresis and other grain characteristics showed that one protein spot was located close to the parameters bread volume and bread height.
Gerbils of a seizure‐sensitive strain have a mitochondrial inner membrane protein with different isoelectric points from those of a seizure‐resistant strain
Authors: Omori Akira , Ichinose Sachiyo , Kitajima Satoko , Shimotohno Kumiko W. , Murashima Yoshiya L. , Shimotohno Kunitada , Seto‐Ohshima Akiko
Published: December 2002

The distribution of proteins in the cerebral cortex of a seizure‐sensitive (SS) strain of gerbil and its seizure‐resistant (SR) counterpart was profiled using two‐dimensional gel electrophoresis. A series of proteins of similar molecular weight (around 83 kDa) showed small but consistent differences in their isoelectric point (pI) with indistinguishable profiles of distribution between the two strains. Amino acid sequences of peptides produced by limited proteolysis of each protein in the spots from the strains were identical or highly homologous to those of mitofilin, a mitochondrial inner membrane protein (IMMT) in humans. Analysis of cDNA sequences revealed the proteins of these spots to be gerbil mitofilin‐like proteins (gIMMT), with a few base substitutions between SS and SR strains, in particular within a region near a putative transmembrane domain that is highly conserved in humans and gerbils. The amino acid at the site was acidic, Glu in humans and Asp in the strain SR of gerbil and a neutral, Asn in strain SS. In addition to these base substitutions, production of multiple species of mRNA for gIMMT by alternative splicing was observed.
Podocyte‐specific expression of cre recombinase in transgenic mice
Authors: Moeller Marcus J. , Sanden Silja K. , Soofi Abdulsalam , Wiggins Roger C. , Holzman Lawrence B.
Published: December 2002

Summary: We report a transgenic mouse line that expresses Cre recombinase exclusively in podocytes. Twenty‐ four transgenic founders were generated in which Cre recombinase was placed under the regulation of a 2.5‐kb fragment of the human NPHS2 promoter. Previously, this fragment was shown to drive beta‐galactosidase (β‐gal) expression exclusively in podocytes of transgenic mice. For analysis, founder mice were bred with ROSA26 mice, a reporter line that expresses β‐gal in cells that undergo Cre recombination. Eight of 24 founder lines were found to express β‐gal exclusively in the kidney. Histological analysis of the kidneys showed that β‐gal expression was confined to podocytes. Cre recombination occurred during the capillary loop stage in glomerular development. No evidence for Cre recombination was detected in any of 14 other tissues examined. genesis 35:39–42, 2003. © 2002 Wiley‐Liss, Inc.
Introduction of cell markers into germ layer tissues of the mouse gastrula by whole embryo electroporation
Authors: Davidson Bruce P. , Tsang Tania E. , Khoo Poh‐Lynn , Gad Jacqueline M. , Tam Patrick P.L.
Published: December 2002

Summary: We have optimized the technique of electroporation for introducing genetic markers into cells of the gastrulating mouse embryo to follow cell fates, tissue movement, and lineage differentiation. Using a plate‐needle electrode combination and specific route of plasmid delivery, labeling could be targeted to discrete regions of the epiblast or the endoderm of the late gastrula. Among the various types of fluorescent and chromogenic reporter constructs tested, those driven by CMV promoter are efficient and strong expression can be detected as soon as 2–3 h after electroporation. The efficacy of marking cell lineages by CRE‐mediated activation of reporters proved to be inefficient for tracking cell lineages due to an obligatory 8–9‐h lag from the electroporation of constructs to the expression of reporter. This significant time lag also raises concern of the temporal precision at which tissue‐ or stage‐specific knock‐out or activation of genetic activity may be achieved by the Cre‐loxP mechanism. genesis 35:57–62, 2003. © 2002 Wiley‐Liss, Inc.
How isotopic fractionation of snowmelt affects hydrograph separation
Authors: Taylor Susan , Feng Xiahong , Williams Mark , McNamara James
Published: December 2002

We present the isotopic composition of meltwater samples from four seasonal snowpacks: a warm, maritime snowpack in California; a temperate continental snowpack in Vermont; a cold continental snowpack in Colorado; and an Arctic snowpack in Alaska. Despite the very different climate conditions the δ18O of meltwater from all four snowpacks increased as melting progressed. This trend is consistent with theoretical results that model isotopic exchange between water and ice as meltwater percolates through a snowpack.

We have estimated the systematic error in the hydrograph separation if the isotopic composition of a snow core were used in place of that of meltwater. Assuming no error in the old water or stream water values, the error in the new water fraction depends on: (1) the isotopic difference between the snow core and the old water; (2) the isotopic difference between the snow core and the meltwater; and (3) the new water fraction contributing to the stream flow during a spring melt event. The error is large when snowmelt contributes a dominant fraction of the stream flow, which may be expected where infiltration of snowmelt is limited (e.g. permafrost, urban areas). A particular challenge will be how to incorporate the changes in isotopic composition of meltwater measured at a point into hydrograph separation models conducted at the watershed scale. Published in 2002 by John Wiley & Sons, Ltd.
Net ecosystem CO2 exchange measured by autochambers during the snow‐covered season at a temperate peatland
Authors: Bubier Jill , Crill Patrick , Mosedale Andrew
Published: December 2002

Net ecosystem exchange of CO2 was measured at a temperate peatland in southeastern New Hampshire. Classified as a mineral‐poor fen owing to deep, water‐logged peats that are influenced to a limited extent by groundwater, the ecosystem is dominated by plants such as sedges (Carex spp.) and evergreen shrubs. Ten automatic chambers measured fluxes every 3 h by sampling changes in headspace concentration of CO2 from November 2000 through March 2001. The fen was covered in snow for most of this period and CO2 was emitted from the snow pack throughout the winter. The largest fluxes were associated with ground temperatures of 0°C and with declining atmospheric pressure. CO2 effluxes up to 3 µmol m−2 s−1 were recorded when the ground temperature reached the thaw point. Fluxes were lower when the ground temperature rose above 0°C, however, suggesting that the large fluxes were associated with a build up and release of stored CO2 degassing as soon as the ground thawed, or by enhanced microbial activity associated with freeze–thaw dynamics. The large number of thaw events coupled with frequent short‐term releases of CO2 suggest that degassing occurred on a regular basis with changes in atmospheric pressure and/or microbial decomposition occurred beneath the snowpack. The extent of soil freezing prior to thaw was also an important factor, with colder soils yielding smaller CO2 emissions upon thaw. Although most of the observed CO2 flux was efflux from the ecosystem, occasional CO2 uptake by the ecosystem of up to 1 µmol m−2 s−1 was also observed, indicating small rates of photosynthesis even during winter. Photosynthesis occurred only when the ground temperature was >0°C. The implications for a warmer climate are unclear. If warmer winter temperatures yield less snow in the temperate region, then soils could freeze more deeply and result in lower CO2 emissions. However, if less snow results in a higher frequency of freeze–thaw events, then winter CO2 emissions could be larger with a warmer climate. Copyright © 2002 John Wiley & Sons, Ltd.
Interannual variations in snowpack in the Crown of the Continent Ecosystem
Authors: Selkowitz David J. , Fagre Daniel B. , Reardon Blase A.
Published: December 2002

Ecosystem changes such as glacier recession and alpine treeline advance have been documented over the previous 150 years in the Rocky Mountains of northern Montana and southern British Columbia and Alberta, a region known as the Crown of the Continent Ecosystem (CCE). Such changes are controlled, at least partially, by variations in snowpack. The CCE consists primarily of public lands, the majority of which is undeveloped or wilderness. Consequently, this region is well suited for an examination of long‐term snowpack variation and associated ecosystem change. Data from nine SNOTEL sites provide an indication of the daily accumulation and ablation of snowpack over the period 1977–2001, as well as the relationship between precipitation, temperature and snowpack. 1 April data from 21 snow courses indicated the extent of regional snowpack variation and trends over the period 1950–2001, and 1 May data from three snow courses in Glacier National Park allow this record to be extended back to 1922. SNOTEL data suggest CCE snowpacks are larger and more persistent than in most regions of the western USA, and that water year precipitation is the primary control on 1 April snow water equivalent (SWE). Snow course data indicate that variations in both 1 April and 1 May mean SWE are closely tied to the Pacific decadal oscillation, an El Niño–southern oscillation‐like interdecadal pattern of Pacific Ocean climate variability. Despite relatively stable snowpacks and summer temperatures since 1922, the glaciers in Glacier National Park have receded steadily during this period, implying a significant climatic shift between their Little Ice Age glacial maxima (ca 1860) and 1922. Published in 2002 by John Wiley & Sons Ltd.
Cytokine, chemokine, and matrix metalloproteinase response after sulfur mustard injury to weanling pig skin
Authors: Sabourin Carol L. K. , Danne Michele M. , Buxton Kristi L. , Casillas Robert P. , Schlager John J.
Published: December 2002

Cutaneous exposure to sulfur mustard [bis(2‐chloroethyl) sulfide; SM] produces a delayed inflammatory skin response and severe tissue injury. Pig skin has organ similarities to human skin that is characterized by the content and types of epidermal lipids, the density of hair follicles and presence of sweat glands, which together afford penetration of topically applied compounds, complex inflammatory responses, and subsequent wound healing. The goal of this study was to identify in vivo proinflammatory biomarkers of the SM porcine skin injury within 72 h after SM challenge, using the weanling pig model. Changes in gene expression of inflammatory mediators were examined at 3, 6, 24, 48, and 72 h, using subtraction library analyses and by quantitation of selected transcripts by reverse transcription–polymerase chain reaction (RT–PCR). Sequence analysis of subtraction libraries identified up‐regulation of IL‐8 at 24, 48, and 72 h. No other specific proinflammatory gene transcripts were isolated from the libraries. Specific transcript RT–PCR analysis showed increased production of interleukin‐1β (IL‐1β), interleukin‐6 (IL‐6), interleukin‐8 (IL‐8), and matrix metalloproteinase‐9 (MMP‐9, gelatinase B) mRNA levels in response to SM exposure. Tumor necrosis factor‐α (TNF‐α) expression was only slightly increased and no change in the levels of expression was observed for monocyte chemoattractant protein‐1 and MMP‐2. This study identifies the main proinflammatory mediators involved in SM‐induced skin injury in a weanling pig model. The results suggest transcriptional activity in the inflammatory response proteins IL‐8, IL‐6, IL‐1β, and MMP‐9 and modest changes in TNF‐α that together produce inflammation and contribute to the pathogenesis of SM dermatotoxicity. Therefore, drugs preventing SM‐induced inflammation should be prime candidates for medical intervention to lessen collateral inflammation associated with tissue destruction. © 2002 Wiley Periodicals, Inc. J Biochem Mol Toxicol 16:263–272, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.10050
The roles of cytochrome b5 in cytochrome P450 reactions
Authors: Porter Todd D.
Published: December 2002

Cytochrome b5, a 17‐kDa hemeprotein associated primarily with the endoplasmic reticulum of eukaryotic cells, has long been known to augment some cytochrome P450 monooxygenase reactions, but the mechanism of stimulation has remained controversial. Studies in recent years have clarified this issue by delineating three pathways by which cytochrome b5 augments P450 reactions: direct electron transfer of both required electrons from NADH–cytochrome b5 reductase to P450, in a pathway separate and independent of NADPH–cytochrome P450 reductase; transfer of the second electron to oxyferrous P450 from either cytochrome b5 reductase or cytochrome P450 reductase; and allosteric stimulation of P450 without electron transfer. Evidence now indicates that each of these pathways is likely to operate in vivo. © 2002 Wiley Periodicals, Inc. J Biochem Mol Toxicol 16:311–316, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.10052
Use of [125I]4′‐iodoflavone as a tool to characterize ligand‐dependent differences in Ah receptor behavior
Authors: Swanson Hollie I. , Whitelaw Murray L. , Petrulis John R. , Perdew Gary H.
Published: December 2002

We have synthesized [125I]4′‐iodoflavone to study Ah receptor (AhR)–ligand interactions by a class of AhR ligands distinct from the prototypic ligand 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD). This radioligand allows the comparison of AhR–ligand interactions using a ligand that differs in AhR affinity, and yet has the same radiospecific activity as [125I]2‐iodo‐7,8‐dibromodibenzo‐p‐dioxin. Specific binding of [125I]4′‐iodoflavone with the AhR was detected as a single radioactive peak (∼9.7 S) following density sucrose gradient analysis. Cytosolic extracts from both Hepa 1 and HeLa cells were used as the source of mouse and human AhR, respectively. A ∼6.7 S form of radioligand‐bound Ah receptor was detected in the high salt nuclear extracts of both cell lines. In HeLa cells approximately twofold more [125I]4′‐iodoflavone–AhR 6 S complex, compared with [125I]2‐iodo‐7,8‐dibromodibenzo‐p‐dioxin, was recovered in nuclear extracts. A comparison of the ability of 4′‐iodoflavone and TCDD to cause time‐dependent translocation of AhR‐yellow fluorescent protein revealed that 4′‐iodoflavone was more efficient at enhancing nuclear accumulation of the receptor. These results suggest that [125I]4′‐iodoflavone is a particularly useful and easily synthesized ligand for studying the AhR. © 2002 Wiley Periodicals, Inc. J Biochem Mol Toxicol 16:298–310, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.10053
Biochemical characteristics of purified beef liver NADPH–cytochrome P450 reductase
Authors: Arinç Emel , Ļelik Haydar
Published: December 2002

NADPH–cytochrome P450 reductase, an obligatory component of the cytochrome P450 dependent monooxygenase system, was purified to electrophoretic homogeneity from beef liver microsomes. The purification procedure involved the ion exchange chromatography of the detergent‐solubilized microsomes on first and second DEAE‐cellulose columns, followed by 2′,5′‐ADP Sepharose affinity chromatography. Further concentration of the enzyme and removal of Emulgen 913 and 2′‐AMP were accomplished on the final hydroxylapatite column. The enzyme was purified 239‐fold and the yield was 13.5%. Monomer molecular weight of the enzyme was estimated to be 76000 ± 3000 (N = 5) by SDS‐PAGE. The absolute absorption spectrum of beef reductase showed two peaks at 455 and 378 nm, with a shoulder at 478 nm, characteristics of flavoproteins. The effects of cytochrome c concentration, pH, and ionic strength on enzyme activity were studied. Reduction of cytochrome c with the enzyme followed Michaelis–Menten kinetics, and the apparent Km of the purified enzyme was found to be 47.7 μM for cytochrome c when the enzyme activity was measured in 0.3 M potassium phosphate buffer (pH 7.7). Stability of cytochrome c reductase activity was examined at 25 and 37°C in the presence and absence of 20% glycerol. The presence of glycerol enhanced the stability of cytochrome c reductase activity at both temperatures. Sheep lung microsomal cytochrome P4502B and NADPH–cytochrome P450 reductase were also purified by the already existing methods developed in our laboratory. Both beef liver and sheep lung reductases were found to be effective in supporting benzphetamine and cocaine N‐demethylation reactions in the reconstituted systems containing purified sheep lung cytochrome P4502B and synthetic lipid, phosphatidylcholine dilauroyl. © 2002 Wiley Periodicals, Inc. J Biochem Mol Toxicol 16:286–297, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.10054
Business ideologies and perceived breach of contract during downsizing: the role of the ideology of employee self‐reliance
Authors: Edwards John C. , Rust Kathleen G. , McKinley William , Moon Gyewan
Published: December 2002

This paper represents an initial effort to explore the empirical relationship between business ideologies and perceptions of organizational downsizing. The results of four studies, two conducted in the US and one each in Singapore and Korea, suggest that respondents' belief in the ideology of employee self‐reliance reduces the degree to which they perceive layoffs as a breach of the psychological contract. This finding appears to generalize to respondents' perceptions of their own layoffs and also to respondents' perceptions of layoffs happening to others. We spell out the implications of these results for the evolving theory of the ideological foundations of perceptions of downsizing. Copyright © 2003 John Wiley & Sons, Ltd.
An electrochemical investigation into the galvanic corrosion of carbon steel coupled to carbon fibres
Authors: Bozzini B. , Fanigliulo A.
Published: December 2002

The problem of galvanic coupling of mild steel to carbon fibres in aqueous solutions relevant to environmental exposure cases is attacked in this research. Acid sulphate and near neutral chloride and bicarbonate solutions are considered. The application background of this investigation is the mechanical joining of carbon‐fibre reinforced polymer‐matrix composites. This research is based on the following electrochemical measurements: galvanic current, corrosion potential, linear‐sweep voltammetry, electrochemical impedance spectroscopy and time‐dependent impedance. The combination of electrochemical measurements performed directly on the galvanically coupled system and on the single materials exposed to the environments of interest, gives insight into the kinetic and mechanistic factors leading to a given, time dependent behaviour of the galvanic couple. Time drifts of the corrosion performance of the couple were assessed and passivation or localised corrosion phenomena highlighted.
Zum Korrosionsverhalten von Nicrofer 3033 in hochkonzentrierter Schwefelsäure
Authors: Werner H. , Riedel G. , Brill U.
Published: December 2002

Untersuchungen zum Korrosionsverhalten von Nicrofer 3033 (1.4591) erfolgten in 93%iger und 95–99%iger technischer Schwefelsäure bei Temperaturen von 70–200°C. 6‐h‐Versuche mit gravimetrischer Auswertung und Messung des Freien Korrosionspotentials und 48‐h‐Versuche mit gravimetrischer Auswertung dienten zur Ermittlung des Einflusses von Schwefelsäurekonzentration und Temperatur bei An‐ und Abwesenheit von SO2 auf die Beständigkeit von Blechproben. Der Einfluss der Strömungsgeschwindigkeit wurde in 6‐h‐Versuchen durch Rotation von Rohrproben bei Umfangsgeschwindigkeiten bis 2 m/s untersucht.

Aus den Potential‐ und gravimetrischen Messungen folgt für Temperaturen ab 100°C eine Beständigkeit mit ≤ 0,1 mm/a für Nicrofer 3033 (1.4591) ab etwa 98,5%. Um 125°C scheint jedoch ein Gebiet zu existieren, wo zumindest bei längerer Versuchsdauer die Beständigkeit bis herab zu etwa 97,5% erhalten bleibt. Untersuchungen zum Strömungseinfluss weisen darauf hin, dass in dem genannten Gebiet mit zunehmender Strömungsgeschwindigkeit wieder eine Aktivierung erfolgt. Bei den anderen Temperaturen ist dagegen der Strömungseinfluss gering.

Diese Ausweitung des Beständigkeitsbereiches um 125°C belegt, dass die Temperaturabhängigkeit von Nicrofer 3033 (1.4591) in hochkonzentrierter Schwefelsäure nicht monoton ist. Es treten in Abhängigkeit von der Schwefelsäurekonzentration bei unterschiedlichen Temperaturen Korrosionsmaxima und ‐minima auf. Bei Anwesenheit von SO2 erfolgt nur bei niedrigen Versuchstemperaturen, 80°C, 100°C im 6‐h‐Versuch und 70°C, 80°C im 48‐h‐Versuch, eine Einengung des Beständigkeitsbereiches.
The stainless steel screw as an orthopaedic implant
Authors: Rozman J. , Kmetič M. , Bunc M. , Pihlar B.
Published: December 2002

The study reported here dealt with the metallographical inspection and analysis of corrosion behavior of screws for mild Slipped Capital Femoral Epiphysis (SCFE), which is a serious orthopedical problem in early adolescence. The screws were fabricated from low carbon, austenitic grade stainless steel type 316L (AISI) with 1600 ppm of nitrogen (316LN2). They were clinically tested in a nearly 25‐year‐long study where patients in early adolescence were operated with these screws with the fixation in situ. Since the results obtained in all patients were similar, we present the results obtained in screws removed after 3 years of implantation from a 14‐year‐old boy. Metallographical inspection results reveal that a low content of carbon in the SS 316LN2, and annealing this material at a high temperature ensures the monophasic microstructure of austenitic grains. In the grains twin bands that appeared during mechanical deformation were observed. As the hardness measured at the stalk (262 HV) was lower than that measured at the head of the screw (293 HV) it was concluded that cold mechanical deformation of the head was much more extensive than that of the stalk. Accordingly, corrosion of the head could be more probable than that of the stalk. Corrosion behavior of the screw in simulated physiological media (0.9% NaCl solution), carried out by the electrochemical method, gave an Ecorr of −0.124 V (vs. SCE), corrosion current density of 21 nA/cm2, and corrosion rate of 0.010 ± 0.005 mpy. This low corrosion rate indicates that SS 316LN2 expresses relatively high corrosion resistance in a saline solution. However, potentiodynamic polarization measurements, where the specimen was driven to more than 1.8 V above the Ecorr., showed that in the region between −0.1 and 0.15 V the specimen corroded, while around 0.2 V a small valley appeared where passivation proceeded. The narrow passive region between 0.15 and 0.25 V indicated that chlorides prevented the formation of thick protecting films. With potentials more positive than 0.3 V the passivating film broke down and the specimen began to corrode. These data indicate that SS 316LN2 can not be effectively protected by passivation since it is not corrosion resistant in a chloride containing environment.
Soy isoflavonoid equol modulates the growth of benign and malignant prostatic epithelial cells in vitro
Authors: Hedlund Tammy E. , Johannes Widya U. , Miller Gary J.
Published: December 2002

BACKGROUND

The dietary consumption of high levels of soy has been linked to reduced risks for prostate cancer (PC) in Asians and vegetarians. In vitro studies have focused on the two most abundant isoflavones in soy, genistein and daidzein. However, daidzein is differentially metabolized by gut microflora in humans, yielding compounds with very different bioactivities and half‐lives. Asians are significantly more likely to produce the metabolite equol than Caucasians, suggesting its role in the prevention of PC. We hypothesize that equol is a bioactive metabolite that exerts direct antiproliferative effects on prostatic epithelial cells.

METHODS

Benign and malignant prostatic epithelial cells were treated in vitro with equol, genistein, and daidzein by using the range of concentrations found in the prostatic fluids of Asians consuming soy. Growth and cell cycle distribution were analyzed over time.

RESULTS

After 9 days of treatment, equol inhibited growth of benign human prostatic epithelial cells (PrEC) by 37% at 10−6 M and 80% at 10−5 M. Although genistein also had profound effects, daidzein appeared only one tenth as potent as equol. Equol and daidzein caused an accumulation of cells in G0/G1, whereas genistein arrested cells in G2/M. The isoflavonoids demonstrated differential effects on the established PC cell lines 22Rv1, LNCaP, LAPC‐4, PC‐3, and DU 145. PC‐3 cells showed the greatest resistance.

CONCLUSION

Equol is a biologically active metabolite of daidzein that has potent antiproliferative effects on benign and malignant prostatic epithelial cells at concentrations that can be obtained naturally through dietary soy consumption. Prostate 54: 68–78, 2003. © 2002 Wiley‐Liss, Inc.