bluuebunny/crossref_metadata_2025 huggingface dataset:
Capillary electrophoresis to assess drug metabolism induced in vitro using single CYP450 enzymes (Supersomes™): Application to the chiral metabolism of mephenytoin and methadone
Authors: Prost Francine , Thormann Wolfgang
Published: July 2003

Capillary electrophoresis (CE) with multiwavelength absorbance detection is demonstrated to be an effective tool for the assessment of in vitro drug metabolism studies using microsomes containing single human cytochrome P450 enzymes (CYPs) expressed in baculovirus‐infected insect cells (Supersomes™). Mephenytoin (MEPH), dextromethorphan, diclofenac, caffeine, and methadone (MET) were successfully applied as test substrates for CYP2C19, CYP2D6*1, CYP2C9*1, CYP1A2, and CYP3A4, respectively. For each system, the CE‐based assay could be shown to permit the simultaneous analysis of the parent drug and its targeted metabolite. Using a chiral micellar electrokinetic capillary chromatography assay, the aromatic hydroxylation of MEPH catalyzed by CYP2C19 could thereby be confirmed to be highly stereoselective, an aspect that is in agreement with data obtained via urinary analysis after intake of racemic MEPH by extensive metabolizer phenotypes. The MET to 2‐ethylidene‐1,5‐dimethyl‐3,3‐diphenylpyrrolidine (EDDP) conversion was investigated with a chiral zone electrophoresis assay. Incubation of racemic and nonracemic MET with CYP3A4 revealed no stereoselectivity for the transformation to EDDP, whereas no EDDP formation was observed with CYP1A2. CYP2C9 and CYP2C19 provided enhanced formation of R‐EDDP and CYP2D6 incubation resulted in the preferential conversion to S‐EDDP. Investigations using racemic MET and human liver microsomes revealed a modest stereoselectivity with an R/S EDDP ratio < 1 which is similar to the in vivo findings in urine.
Enantiomeric separation of citalopram and its metabolites by capillary electrophoresis
Authors: Mandrioli Roberto , Fanali Salvatore , Pucci Vincenzo , Raggi Maria A.
Published: July 2003

A simple and fast capillary electrophoretic method has been developed for the enantioselective separation of citalopram and its main metabolites, namely N‐desmethylcitalopram and N,N‐didesmethylcitalopram, using β‐cyclodextrin (β‐CD) sulfate as the chiral selector. For method optimisation several parameters were investigated, such as CD and buffer concentration, buffer pH, and capillary temperature. Baseline enantioseparation of the racemic compounds was achieved in less than 6 min using a fused‐silica capillary, filled with a background electrolyte consisting of a 35 mM phosphate buffer at pH 2.5 supplemented with 1% w/v β‐CD sulfate and 0.05% w/v β‐CD at 25°C and applying a voltage of −20 kV. A fast separation method for citalopram was also optimized and applied to the analysis of pharmaceutical formulations. Racemic citalopram was resolved in its enantiomers in less than 1.5 min using short‐end injection (8.5 cm, effective length) running the experiments in a background electrolyte composed of a 25 mM citrate buffer at pH 5.5 and 0.04% w/v β‐CD sulfate at a temperature of 10°C.
Enantiomeric separation of chiral peptide nucleic acid monomers by capillary electrophoresis with charged cyclodextrins
Authors: Galaverna Gianni , Sforza Stefano , Tedeschi Tullia , Corradini Roberto , Dossena Arnaldo , Marchelli Rosangela
Published: July 2003

Direct chiral separation of chiral peptide nucleic acid (PNA) monomers has been achieved for the first time by capillary electrophoresis (CE) with charged cyclodextrins as chiral selectors added to the electrophoretic buffer. Selectively modified 6‐deoxy‐6‐N‐histamino‐β‐cyclodextrin and sulfobutyl ether‐β‐CD were successfully used as chiral selectors for the enantiomeric separation of chiral monomers based on different aminoethylamino acids bearing thymine or adenine as nucleobases. Chiral separations were obtained at low selector concentrations (1–3 mM) with good enantioselectivity and resolution factors. Separations were optimized as a function of pH in order to exploit the effect of the electrostatic interactions between the oppositely charged selector and selectand. The method has been applied to the analysis of the enantiomeric excess of chiral monomers used for the solid phase synthesis of chiral PNA oligomers. CE chiral analysis showed that a very high enantiomeric purity was generally achieved in the synthesis of all monomers, except for histidine and aspartic acid based monomers in which ca. 10% of the “wrong” enantiomer was always present.
Microchip electrophoresis for chiral separations
Authors: Belder Detlev , Ludwig Martin
Published: July 2003

Microchip electrophoresis (MCE) is a promising new technique for the separation of enantiomers. This recently introduced technique enables chiral separations to be performed in seconds on tiny micromachined devices. This review is intended to give a brief introduction into the principles of chiral separations with MCE with regard to methodology and instrumentation. Different approaches to realize chiral separations in microfluidic devices are described and discussed. This review gives an overview of original work done in this field with emphasis on approaches to improve detection and resolution in chiral MCE.
Enantioseparation of dihydrofurocoumarin derivatives by various separation modes of capillary electrophoresis
Authors: Egger Matthew D. , Liu Ying , Sevčík Juraj , Tesařová Eva , Rozhkov Roman , Larock Richard C. , Armstrong Daniel W.
Published: July 2003

Chiral dihydrofurocoumarin compounds are currently the focus of industrial and pharmacological research. These derivatives have been shown to possess many physiological properties that could be medically beneficial. This work proposes four different chiral separation methods using capillary electrophoresis and micellar capillary electrophoresis (MCE). Several different cyclodextrin chiral selectors were examined to evaluate their effectiveness in the enantioseparation of dihydrofurocoumarins. In addition, the effects of the chiral selector concentration, the presence of an organic modifier, run buffer pH, and in two cases, the ratio between the chiral selector and an additional charged pseudophase were investigated. Overall, the best separations for this class of chiral compounds were achieved using sulfated β‐cyclodextrins at low pH in the reversed polarity mode.
Polymeric alkenoxy amino acid surfactants: I. Highly selective class of molecular micelles for chiral separation of β‐blockers
Authors: Rizvi Syed A. A. , Shamsi Shahab A.
Published: July 2003

Two amino acid‐based alkenoxy micelle polymers were synthesized for this study. These include polysodium N‐undecenoxy carbonyl‐L‐leucinate (poly‐L‐SUCL) and polysodium N‐undecenoxy carbonyl‐L‐isoleucinate (poly‐L‐SUCIL). The polymerization time and concentration of the synthesized micelle polymers were optimized by 1H‐nuclear magnetic resonance (NMR) and capillary electrophoresis (CE) experiments. Detailed physicochemical properties (1H NMR, critical micelle concentration (CMC), optical rotation, partial specific volume, aggregation number, and polarity) were determined, and these molecular micelles were introduced as a pseudostationary phase in micellar electrokinetic chromatography to study the molecular recognition and to develop a method for simultaneous separation of eight chiral β‐blockers. It is found that poly‐L‐SUCL gives overall better chiral resolution and wider chiral window than poly‐L‐SUCIL. After optimizing the type of micelle polymer, injection size and temperature, simultaneous separation and enantioseparation of eight β‐blockers were achieved in less than 35 min. A comparison with the amide‐type surfactants of the same polar head group and alkyl chain length showed that carbamate‐type surfactants always work better than the corresponding amide‐type surfactant.
Influence of injection gate definition on the flow‐front approximation in numerical simulations of mold‐filling processes
Authors: Modi Dhiren , Šimáček Pavel , Advani Suresh
Published: July 2003

Flow through porous media has been used to model resin impregnation in composites manufacturing processes such as resin transfer molding. Many numerical schemes have been used to explore the efficiency and accuracy in description of the movement of the liquid front when it is introduced through injection gates into a mold containing stationary and compacted fibrous porous media. In all numerical schemes, injection gates are modelled with a single node. Mathematically, a single node definition for a finite radius injection gate imparts a singularity. In this paper, an approach to avoid this singularity by modelling the injection gate with more than one node is presented. An analytical solution relating the fill time to the injection gate radius is developed for a constant pressure injection from a spherical injection gate into an isotropic media. A new parameter ‘mesh density level’, defined as the ratio of the injection radius to the element size, is used to investigate the accuracy and the convergence of the numerical results. It is shown that the numerical results converge when the mesh density level is increased. The accuracy of the results depends on the ratio of the flow‐front radius to the injection gate radius as well as on the mesh density level. In many situations, a spherical injection gate may not represent the correct physics and model simplification may be necessary.

The impact of such simplifications is also quantified. The systematic analysis presented in this paper should prove useful to the modeller in taking the decision whether to select the proper, geometric definition for the injection gate to obtain accurate results or to define the injection gate using a single node and be aware of the errors introduced due to the singularity. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis and Characterization of Photocrosslinkable Biodegradable Polymers Derived from 4‐Hydroxycinnamic Acid
Authors: Nagata Minoru , Hizakae Sigeki
Published: July 2003

A novel series of photocrosslinkable biodegradable polymers was prepared by a high‐temperature solution polycondensation from a dichloride of 4,4′‐(adipoyldioxy)dicinnamic acid (CAC) and alkane diols of various methylene lengths (HO(CH2)nOH; n = 6–10) or poly(ethylene glycol)s (PEG) of various molecular weights $(\bar M = 200 - 8300)$. The CAC was synthesized by the condensation of adipoyl chloride and 4‐hydroxycinnamic acid. The chemical structures and properties of these polymers were characterized by elemental analysis, ultraviolet‐visible spectroscopy (UV‐VIS), Fourier transform infrared spectroscopy (FT‐IR), 1H NMR spectroscopy, differential scanning calorimertry (DSC), and thermogravimetry (TG). All polymers had a high molecular weight and good solubility in organic solvents. DSC showed that Tm values of CACn (134–180 °C) were much higher than those of CACEm (25–56 °C). The CACE200 degraded very rapidly in the buffer solutions (pH 7.2) of Ps. Cepacia or Rh. delemar lipase at 37 °C, while CACn resisted the hydrolysis by these lipases during the test period. The ultraviolet light irradiation (λ ≥ 280 nm) caused the photocrosslinking reaction by an intermolecular dimerization at ambient temperature without a photosensitizer, as examined by UV‐VIS, FT‐IR spectroscopy, and gel formation. The gels prepared from CACEm (m ≈ 1 000) were swollen in water and showed characteristic properties of a hydrogel. The irradiation time and the molecular weight of PEGs controlled the degree of swelling of these hydrogels. The CACE8 300 gel irradiated for 20 min showed the largest degree of swelling of 10.5.

Weight loss of a CACE200 film as a function of time in a phosphate buffer solution containing no lipase (□), Ps. cepacia lipase (•), or Rh. delemar lipase (○) at 37 °C.

magnified image

Weight loss of a CACE200 film as a function of time in a phosphate buffer solution containing no lipase (□), Ps. cepacia lipase (•), or Rh. delemar lipase (○) at 37 °C.
Interferometric Sizing of Single‐Axis Birefringent Glass Fibers
Authors: Onofri Fabrice , Lenoble Anne , Radev Stefan , Bultynck Hervé , Guering Paul‐Henri , Marsault Nicolas
Published: July 2003

This paper deals with the on‐line sizing of small diameter glass fibers (i.e. d<30 μm) produced for textiles and reinforcement applications. Two models based on the Lorenz‐Mie Theory are introduced to predict the basic light scattering properties and the response of a phase Doppler interferometer (PDI) to the sizing of infinite glass fibers. Among other parameters, these models take into account particular effects such as the fiber's single‐axis birefringence and the fiber's refractive index dependence on its cooling rate (i.e. diameter). Both effects have a weak influence on the mean response of the PDI but a strong influence on the resonance structures of its phase‐diameter relationship. Two optical set‐ups were selected from a numerical optimization procedure and tested experimentally. Experimental results are presented demonstrating the validity of the models and the ability of the developed PDI set‐ups to study some features of the fiber drawing‐process: fluctuations of the fiber diameter when the nozzle is submitted to a convective perturbation and, when the fiber take‐up velocity is modulated, the detection of hollow fibers.
Quantitative Measurement of Planar Droplet Sauter Mean Diameter in Sprays using Planar Droplet Sizing
Authors: Domann Roland , Hardalupas Yannis
Published: July 2003

The purpose of this investigation is to assess and improve the accuracy of Sauter Mean Diameter measurements in dense sprays using a Planar Droplet Sizing (PDS) technique, based on the intensity ratio of scattered and fluorescence light. A novel data processing method of the PDS technique is suggested, which was derived from a theoretical light scattering investigation, and reduced possible sizing errors larger than 30% to below 10%. The novel approach for droplet sizing was applied to measure in a spray generated by a pressure swirl atomiser in a liquid‐fuelled burner operated with water at isothermal conditions, in order to avoid the effect of liquid evaporation on the accuracy of PDS technique. The Sauter Mean diameter results from the PDS technique were compared to Phase Doppler Anemometer (PDA) sizing measurements. Good agreement was obtained between the two techniques in dense regions of the spray. Discrepancies remained in dilute spray regions due to systematic statistical uncertainties of the PDS technique and the dynamic range of the intensity of the CCD cameras, which did not allow detection of large single droplets in the dilute spray region.
Bubble Velocity and Size Measurement with a Four‐Point Optical Fiber Probe
Authors: Guet Sébastien , Fortunati Robbert V. , Mudde Robert F. , Ooms Gijs
Published: July 2003

The possibility to measure the velocity and size of individual bubbles in a high‐void fraction bubbly flow is investigated by using a four‐point optical fiber probe. The air bubbles have an initial spherical equivalent diameter ranging from 4 to 10 mm and the void fraction is up to 0.3. Firstly, single bubble experiments show that intrusiveness effects, i.e. bubble deformations due to the probe, are negligible provided that the bubble approaches the probe at the axis of the central fiber. A selection criterion is utilized for multiple bubble experiments. A good compromise can be found between the required accuracy, the duration of the measurements and the number of validated bubbles required for reliable statistical averaging. In an air‐water high‐void fraction vertical bubbly pipe flow, the void fraction obtained with the instrument is found to be in good agreement with both local single‐fiber probe measurements, and with the volume average void fraction obtained from pressure gradient measurements. The area average volumetric gas flow rate, based on the bubble velocity and void fraction as measured with the four‐point probe, agree with the measured gas flow rate. Also, the liquid velocity is measured by means of a laser‐Doppler anemometer, to investigate the slip velocity. The results show that reliable and interesting measurements can be obtained by using a four‐point optical fiber probe in high void fraction flows.
Natural products of the medicinal fungus Ganoderma lucidum: Occurrence, biological activities, and pharmacological functions
Authors: Shiao Ming‐Shi
Published: July 2003

Ganoderma lucidum, a fungus used in traditional Chinese medicine, produces polysaccharides and oxygenated triterpenoids with a very broad spectrum of biological activities and pharmacological functions. Among the Ganoderma triterpenoids, many pairs of C‐3 α/β stereoisomers and C‐3/C‐15 positional isomers have been identified. Biosynthetic study has indicated that the C‐3α series of oxygenated triterpenoids is derived from the C‐3β series via an oxidation‐reduction pathway. The interaction of Ganoderma triterpenoids with human platelets in the induction of aggregation and inhibition of agonist‐induced aggregation and signal transduction has been elucidated. Reduction of cellular mevalonate content to a stage in which cholesterol synthesis is strongly inhibited and cell growth is marginally arrested sensitizes hepatoma cells to the oxygenated triterpenoids. A combination treatment of lovastatin and Ganoderma triterpenoids in animal studies has exhibited a potential anticancer effect. © 2003 The Japan Chemical Journal Forum and Wiley Periodicals, Inc., Chem Rec 3: 172–180; 2003: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.10058
Effects of 17α‐ethinylestradiol on immune parameters in the lizard Sceloporus occidentalis
Authors: Burnham D. Kim , Lackey Amanda , Manering Michelle , Jaensson Elin , Pearson Jamie , Tyler Daniel O. , Melson David , Talent Larry G.
Published: July 2003

We examined the effect of 17α‐ethinylestradiol on immunity of the Western fence lizard, Sceloporus occidentalis. Injection of 17α‐ethinylestradiol resulted in dose‐dependent suppression of peripheral blood leukocyte levels as determined by cell counts, whereas total spleen cell levels were decreased only at higher doses of 17α‐ethinylestradiol. In contrast, spleen cell proliferation was enhanced by 17α‐ethinylestradiol as measured by reduction of MTT to formazan following a two‐way mixed lymphocyte reaction. Antibody responses were unaffected. Effects on peripheral blood leukocyte levels and spleen cell proliferation similar to those observed in response to injection of 17α‐ethinylestradiol were observed following injection of a single dose of hydrocortisone. However, injection of lizards with 17α‐ethinylestradiol did not result in a significant increase in serum cortisol. Results of this study suggest that exposure of Western fence lizards to 17α‐ethinylestradiol leads to decreased numbers of circulating leukocytes and total spleen cell numbers and the enhancement of spleen cell proliferation in a two‐way mixed lymphocyte reaction. These effects probably involve mechanisms other than or in addition to the induction of cortisol release. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 211–218, 2003.
ROS‐dependent caspase‐9 activation in hypoxic cell death
Authors: Kim Jee-Youn , Park Jae-Hoon
Published: July 2003

Mitochondria are known to play a fundamental role in apoptosis by releasing apoptogenic molecules such as cytochrome c into the cytoplasm, thereby sequentially activating initiator caspase‐9. However, the mechanisms of cytochrome c release or caspase‐9 activation in response to hypoxia are unclear. In this report, we show that caspase‐9 is activated by reactive oxygen species (ROS) without involvement of cytochrome c release in hypoxic injury. In addition, activated caspase‐9 induces permeability transition (PT)‐independent cytochrome c release, suggesting that caspase‐9 may disrupt mitochondrial diffusion limit of cytochrome c and serve to amplify further release of cytochrome c.
α‐Melanocyte‐stimulating hormone induces cell death in mast cells: involvement of NF‐κB
Authors: Sarkar Abira , Sreenivasan Yashin , Manna Sunil K
Published: July 2003

Mast cells play a major role in the initiation of inflammation and allergic reactions. As cell numbers are tightly controlled by the interplay of factors affecting cell proliferation, development, and death the regulation of mast cell number may be important. Melanocyte‐stimulating hormone inhibits most forms of inflammation by an unknown mechanism. In the present study, we have found that the α‐melanocyte‐stimulating hormone (α‐MSH) inhibited endotoxin‐mediated nuclear transcription factor κB (NF‐κB) activation in different cells correlated with the expression of α‐MSH receptors. We have also found for the first time that it induces cell death alone or in endotoxin‐stimulated mast cells. α‐MSH‐mediated apoptosis was not observed in NF‐κB overexpressed cells. The inhibitory effect of α‐MSH was mediated through generation of cAMP, as inhibitors of adenylate cyclase and of protein kinase A reversed its inhibitory effect. Overall, our results suggest that NF‐κB is the key molecule involved in α‐MSH‐mediated cell death and this may help to regulate mast cell‐mediated inflammation.
Identification of sites in the cysteine‐rich domain of the class P‐III snake venom metalloproteinases responsible for inhibition of platelet function
Authors: Kamiguti Aura S. , Gallagher Paul , Marcinkiewicz Cezary , Theakston R.David G. , Zuzel Mirko , Fox Jay W.
Published: July 2003

Atrolysin A and jararhagin are class P‐III snake venom metalloproteinases (SVMPs) with three distinct domains: a metalloproteinase, a disintegrin‐like and a cysteine‐rich. The metalloproteinase and the disintegrin‐like domains of atrolysin A and jararhagin contain peptide sequences that interact with α2β1 integrin and inhibit the platelet responses to collagen. Recently, the recombinant cysteine‐rich domain of atrolysin A was shown to have similar effects, but the sequence(s) responsible for this is unknown. In this report, we demonstrate two complete peptide sequences from the homologous cysteine‐rich domains of atrolysin A and jararhagin that inhibit both platelet aggregation by collagen and adhesion of α2‐expressing K562 cells to this protein. In addition, the peptide effects on platelets do not seem to involve an inhibition of GPVI. These results identify, for the first time, sites in the cysteine‐rich domain of SVMPs that inhibit cell responses to collagen and reveal the complexity of the potential biological effects of these enzymes with multifunctional domains.
IL‐4 augments anisomycin‐induced p38 activation via Akt pathway in a follicular dendritic cell (FDC)‐like line
Authors: Lee Hyang-Mi , Jin Hyung-Sung , Park Jae-Won , Park Sun-Mi , Jeon Hye-Kyung , Lee Tae H.
Published: July 2003

Follicular dendritic cells (FDCs) play pivotal roles in germinal center (GC) responses in secondary lymphoid follicles, and their functions are influenced by cytokines present in the GC. We investigated the functional effects of interleukin‐4 (IL‐4) using an established FDC‐like line of HK cells. In spite of the activation of ERK1/2 and PI3K/Akt pathways by IL‐4, which are implicated in the induction of cell proliferation and survival, IL‐4 did not exhibit protective function on anisomycin‐induced apoptosis of HK cells, but rather slightly enhanced it. This IL‐4 effect correlated with the up‐regulation of anisomycin‐induced p38 signaling, which is attenuated by inhibition of the PI3K/Akt pathway. Expression of an active form of Akt increased anisomycin‐elicited activation of p38 and its upstream kinase MKK3/6. Our data indicate a positive cross‐talk between the p38 and PI3K/Akt pathways.
The yeast deubiquitinating enzyme Ubp16 is anchored to the outer mitochondrial membrane
Authors: Kinner Andrea , Kölling Ralf
Published: July 2003

We looked for membrane‐associated Dubs (deubiquitinating enzymes) among the 16 yeast members of the ubiquitin‐specific processing protease (Ubp) family to identify potential regulators of ubiquitin‐dependent processes at membranes. For each of the Ubps examined, a certain fraction was found to be membrane associated. This fraction was only small for most Ubps but quite substantial for some Ubps. For Ubp4/Doa4 almost 40% of the protein was found in the membrane fraction suggesting that this protein performs a major function at membranes, probably at endosomes. Among the proteins tested, only one protein (Ubp16) was exclusively membrane associated. By cell fractionation and immunofluorescence experiments, we could show that Ubp16 is localized to mitochondria. Ubp16 contains an N‐terminal hydrophobic domain that is similar to N‐terminal sequences of other yeast outer mitochondrial membrane proteins. The presence of this putative signal sequence and the result of protease protection experiments suggest that Ubp16 is an integral membrane protein of the outer mitochondrial membrane with an Nin–Cout orientation. Phenotypic characterization of the Δubp16 mutant and overexpression studies further suggest that Ubp16 is probably not important for the general functioning of mitochondria, but that it rather performs a more specialized function at mitochondria.
N‐terminal truncation of the variable subunit stabilizes spinach ferredoxin:thioredoxin reductase
Authors: Manieri W. , Franchini L. , Raeber L. , Dai S. , Stritt-Etter A.-L. , Schürmann P.
Published: July 2003

The variable subunit of spinach ferredoxin:thioredoxin reductase (FTR) has an extended N‐terminus compared to FTRs from other sources and this was proposed to contribute to the instability of the protein. We constructed two N‐terminal truncation mutants of recombinant FTR by removing 16 or 24 residues from the variable subunit. The mutant proteins are readily expressed and show half‐saturation values (S
0.5) for ferredoxin and thioredoxin f comparable to WT. However, truncation increases significantly their stability. Using the stabilized FTR an exposed Cys on its thioredoxin contact surface could be substituted without altering its properties, whereas the replacement of an active site Cys by Ser completely destabilized the protein.
In Schizosaccharomyces pombe chs2p has no chitin synthase activity but is related to septum formation
Authors: Martı́n-Garcı́a Rebeca , Durán Angel , Valdivieso M.-Henar
Published: July 2003

Chitin synthesis occurs in most fungi through the action of different chitin synthase (CS) isoenzymes. In Schizosaccharomyces pombe the chs2
+ gene codes for a protein with significant similarity to CS enzymes, but lacking most of the residues considered to be essential for activity, including the QRRRW domain. Here we show that chs2p is a functional protein that localises to the growing edge of the septum but is not a CS enzyme. Strong over‐expression is lethal, while moderate expression leads to a severe defect in septum formation. These results suggest that chs2p has remained through evolution to play an alternative role in septation.
RETRACTED: Feasibility and safety of moderate hypothermia after acute ischemic stroke
Authors: Jian Su , Yongming Qiou , Zhihua Chen , Yan Chen
Published: July 2003

This article has been retracted at the request of the chief editor(s) and author(s). Reason: this article has been retracted as it plagiarises an earlier article published by Dr Schwab in Stroke 32, 2033–2035 (2001).
A novel tag-recovery model with two size classes for estimating fishing and natural mortality, with implications for the southern rock lobster (Jasus edwardsii) in Tasmania, Australia
Authors: Latour Robert J. , Hoenig John M. , Hepworth Daniel A. , Frusher Stewart D.
Published: July 2003

Multi-year tag-recovery models can be used to derive estimates of age- and year-specific annual survival rates and year-specific instantaneous fishing and natural mortality rates. The latter, which are often of interest to fisheries managers, usually can only be estimated when the tag-reporting rate (λ) and the short-term tag-induced mortality and tag-shedding rate (φ) are known a priori. We present a new multi-year tagging model that permits estimation of instantaneous mortality rates independently of φλ, provided tagged animals from two adjacent size groups are released simultaneously. If the two size groups comprise animals just above and below the minimum harvestable size limit, then it is possible to estimate year-specific instantaneous fishing and natural mortality rates after 2 yr of tagging and tag-recovery. In addition to the standard assumptions of multi-year tag-recovery models, it is necessary to assume that recruited animals have equal selectivity, pre-recruited animals become fully recruited in 1 or 2 yr, and the size groups experience the same natural mortality rate. Applicability of the model to the Tasmania southern rock lobster (Jasus edwardsii) fishery is evaluated using a simulation model and parameters based on data from the lobster fishery; assumptions are likely to be met and precision should be adequate if at least 1000 animals are tagged per year in each size group.
Estimated pup production of harp seals Pagophilus groenlandicus in the White Sea, Russia, in 2000
Authors: Potelov V.A , Golikov A.P , Bondarev V.A
Published: July 2003

Since the 1960s pup production of harp seals Pagophilus groenlandicus in the White Sea was estimated from aerial photographic surveys of visible adult females on the ice. Adult abundance estimations were underestimated because an unknown number of females were in the water during the survey. The absence of a reliable estimation of pup production constrained management initiatives. Aerial photographic surveys of whelping harp seals were conducted in the White Sea 10–12 March 2000. Using a systematic strip transect survey design approach, the number of pups present was estimated as 294 914 with a standard error (s.e.) of 36 168. When pups caught by Russian sealers in the White Sea before the aerial surveys (30 729 pups) were included the total estimated number of pups was 325 643 (s.e. 36 168), whereas the number of adult harp seals was 215 943 (s.e. 22 630). The pup estimate was not corrected for pups born after the survey, but this was not considered to be significant. The new estimation of pup production is higher than thought earlier.
A comparison of fish bycatch communities between areas open and closed to prawn trawling in an Australian tropical fishery
Authors: Stobutzki Ilona , Jones Peter , Miller Margaret
Published: July 2003

The bycatch fish community was compared between areas open and closed to prawn trawling in Australia's Northern Prawn Fishery to investigate the impacts of the fishery. Two regions of a large (∼6648 km2) closure were compared, with three areas in each region, one closed to trawling (Closed) and two open to trawling, one near the closure (Near) and one farther from the closure (Far). Sampling was undertaken both day and night. The two regions and two times were analysed separately using both multivariate and univariate analyses to examine changes in overall community structure and differences in individual species. Overall the results were equivocal with respect to the impact of trawling. The multivariate and univariate analyses showed that in both regions, during both day and night, the bycatch fish community of the Far open area differed from the Near and Closed areas, while the latter were similar. This at least partly reflected differences in depth and sediment. For individual species, most showed no significant difference between the areas open and closed to trawling. Of the significant results there was no consistent tendency for species to be more likely to occur inside the closure or be at a higher density or larger size within the closure. Benthic and demersal species, those more susceptible to capture by prawn trawls, were not consistently less likely to occur or at a lower biomass in the open areas. The lack of a strong contrast in the fish community between the open and closed areas is probably due to the comparatively low effort in the fishery, the highly aggregated nature of the trawling and the fact the fishery does not target the bycatch species. These factors may reduce the potential impact of trawling on the fish bycatch.
The influence of pre-recruitment growth on subsequent growth and age at first spawning in Atlantic herring (Clupea harengus L.)
Authors: Brophy Deirdre , Danilowicz Bret S
Published: July 2003

Calculation of the spawning stock biomass for fisheries management requires information on the numbers or proportions of fish in each age- or length-group that are mature each year. This study was conducted to determine the relationship between growth and age of first reproduction in herring stocks around Ireland. Measurements of otolith size at the onset of the first annulus (O1) were used to compare growth during the first year of life between 1-, 2-, and 3-group spawning herring collected from spawning grounds in the Celtic Sea over a period of 3 years. The 1-group spawning fish had significantly greater mean O1 measurements, and hence showed faster growth on average during the first year of life than 2- or 3-group spawning fish. Fish that exhibited slow growth during the first year were absent from the adult spawning population at age 1, but occurred at similar levels in the samples of 2- and 3-group spawning fish. Regression of O1 radius on fish length at capture showed that growth during the first year of life had a small but significant effect on subsequent growth up to age 3. The relationship between pre-recruitment growth and subsequent growth and age at first spawning has implications for recruitment patterns of juveniles from different nursery areas and for the lifetime fecundity of population components with differential growth.
Vacuolar accumulation and extracellular extrusion of electrophilic compounds by wild‐type and glutathione‐deficient mutants of the methylotrophic yeast Hansenula polymorpha
Authors: Ubiyvovk Vira M. , Maszewski Janusz , Bartosz Grzegorz , Sibirny Andrei A.
Published: July 2003

The methylotrophic yeast Hansenula polymorpha CBS4732 leu2 detoxifies electrophilic xenobiotics by glutathione (GSH)‐dependent accumulation in vacuoles, as shown by fluorescence microscopy. GSH‐dependent and GSH‐independent export of xenobiotic derivatives were also demonstrated by high‐performance liquid chromatography (HPLC). Conjugates of GSH and N‐acetylcysteine with monobromobimane and N‐[1‐pyrene]maleimide were observed among the HPLC fractions, along with unidentified derivatives.
Evaluation of GPS‐based ionospheric TEC map by comparing with VLBI data
Authors: Sekido Mamoru , Kondo Tetsuro , Kawai Eiji , Imae Michito
Published: July 2003

Precise ionospheric total electron content (TEC) map of the Earth is useful, if it is available for calibration of ionospheric dispersive delay for space measurement techniques using microwave such as GPS, VLBI, and spacecraft navigation. Recent rapid development of GPS techniques is making it more realistic that Earth's ionosphere TEC map measured by GPS observation is practically applicable in those space measurements. For the purpose of evaluating the accuracy of the ionospheric TEC map produced from GPS measurements, two cases of TEC maps were compared with dual band VLBI TEC measurements. In one case, local TEC maps produced from observation data using TECMETERs, which are a kind of GPS receiver for TEC measurements, were compared with VLBI data. As the second case, Global Ionosphere Maps (GIMs) generated by the Center for Orbit determination in Europe (CODE) were compared with VLBI data from short baseline to intercontinental baseline. The ionospheric group delay derived from the local TEC map of the first case had about 80 % correlation with VLBI data on 109 km short baseline. Also the group delay computed by using the GIM data of the CODE (GIM/CODE) had about 90 % correlation with VLBI data on that baseline. In comparisons on intercontinental baselines, correlations between GIM/CODE data and TEC measured by VLBI indicated almost unity. Then it was found that more than 90 % of ionospheric TEC could be predictable with that TEC map. Through further statistical analysis of TEC comparison data, the error spectrum of GIM/CODE data was computed. Comparing the obtained error spectrum with error of the spherical harmonics component of the GIM/CODE data, the latter was always smaller than the former, and the error of GIM/CODE data is suspected to be underestimated, especially at low spatial frequency. It was inferred from the spectrum that more than 0.8 TECU of ionosphere perturbations remain in the higher spatial frequency region, which is not covered by the GIM/CODE model. Total accuracy of GIM/CODE data was evaluated around 3.7 – 3.9 TECU. Also phase delay rates derived from the GIM/CODE were compared with VLBI data. It indicated correlation around 0.6 – 0.8 on intercontinental baseline, but it is not enough accuracy for practical use in phase delay rate correction in VLBI observation. The reason for low coincidence is understood by the lack of small scale and short timescale TEC variation information in that TEC map model.
Evolution of the NOy‐N2O correlation in the Antarctic stratosphere during 1993 and 1995
Authors: Muscari Giovanni , de Zafra Robert L. , Smyshlyaev Sergei
Published: July 2003

The sources and sinks of stratospheric reactive nitrogen (NOy) in the Antarctic are known only qualitatively, because of the very few measurements of NOy available in this region. As a result, the effects of stratospheric NOy short‐ and long‐term changes on the stratospheric concentration of ozone, water vapor, and other climate‐forcing agents are still uncertain. To better understand the annual cycle of polar stratospheric NOy, we estimate its concentration in the Antarctic stratosphere during part of 1993 and throughout 1995. These estimates are obtained at seven potential temperature levels, extending from ∼18 to 30 km of altitude, and are associated with ground‐based measurements of another tracer, N2O, in order to produce NOy‐N2O correlation curves that can provide insights on nitrogen sources and sinks. To estimate NOy mixing ratios, we use ground‐based and satellite measurements of major NOy constituents, connected by using air parcel trajectories and supplemented by model calculations of minor contributing species for which no suitable measurements exist. All the available NOy‐N2O correlation points are averaged over three representative seasonal time periods in 1993 and six periods in 1995. Results show very similar correlation curves during the late summer and the fall of 1995, and again during the early spring 1993 compared with the early and late winter of 1995, although there are large seasonal changes due to transport and to condensation of NOy onto polar stratospheric clouds. We calculate a loss from the latter process of ΔN = (6.3 ± 2.6) × 107 kg of stratospheric nitrogen in the southern polar vortex during 1995. We also compare our correlation curves with those obtained in the Antarctic stratosphere during the Atmospheric Trace Molecule Spectroscopy mission ATMOS/ATLAS‐3 in November 1994, finding important similarities but also critical differences that suggest that extra‐vortex air is generally not an adequate representation of prewinter inner vortex conditions. Calculations of NOy winter removal in the Antarctic stratosphere which have used extra‐vortex measurements as a surrogate for prewinter conditions may thus have underestimated true NOy removal. Our prewinter NOy estimates in the vortex core match values obtained by atmospheric models that incorporate upper atmospheric sources of NOy, supporting the belief that such sources have a significant effect on polar stratospheric NOy.
International Research Institute/Applied Research Centers (IRI/ARCs) regional model intercomparison over South America
Authors: Roads J. , Chen S. , Cocke S. , Druyan L. , Fulakeza M. , LaRow T. , Lonergan P. , Qian J.‐H. , Zebiak S.
Published: July 2003

A regional modeling intercomparison project for South America among the (1) Scripps Experimental Climate Prediction Center regional spectral model (RSM), (2) Florida State University nested regional spectral model (FSUNRSM), (3) Goddard Institute for Space Studies regional climate model (RCM), and (4) IRI regional climate model (RegCM2) is described herein. All regional models were driven by the NCEP/NCAR I global reanalysis over a South American domain centered on Brazil. In comparison to new Xie and Arkin 0.5° land observations, the regional models had a seasonal systematic precipitation error that was somewhat similar to the driving NCEP/NCAR reanalysis systematic error, although the regional model ensemble mean error was somewhat smaller, indicating a potential value for using multiple model ensembles. However, correlations, threat scores and biases were not noticeably better. In short, at their current levels of skill, regional models do not yet provide a noticable improvement over large‐scale analyses.
Estimating nonaqueous phase liquid spatial variability using partitioning tracer higher temporal moments
Authors: Jawitz James W. , Annable Michael D. , Demmy George G. , Rao P. S. C.
Published: July 2003

The use of interwell partitioning tracers to quantify the amount of nonaqueous phase liquid (NAPL) in porous media has been demonstrated in several laboratory and field tests. The primary emphasis of work to date has been on the use of first temporal moments of tracer breakthrough curve (BTC) data to estimate the average NAPL saturation. Here we extend the data analysis to the use of tracer BTC second and third temporal moments to estimate the statistical parameters characterizing the NAPL spatial distribution. In particular, we examine the fraction f of the streamlines that contain NAPL and the mean and standard deviation of the distribution of streamline trajectory‐average NAPL saturations. Two models are presented based on discretizing tracer swept volumes into contaminated and uncontaminated zones. The models are applied to data from three‐dimensional numerical simulations, two‐dimensional flow laboratory experiments, and field tests at two sites (Hill Air Force Base, Utah, and a dry cleaner in Jacksonville, Florida). For all cases considered here, good agreement was found between expected (measured) and estimated values of f, the fraction of the tracer swept zone that contained NAPL. The effects of nonlinear and nonequilibrium partitioning as well as correlations between NAPL saturation and saturated hydraulic conductivity are also considered.
Mapping evapotranspiration based on remote sensing: An application to Canada's landmass
Authors: Liu J. , Chen J. M. , Cihlar J.
Published: July 2003

The evapotranspiration (ET) from all Canadian landmass in 1996 is estimated at daily steps and 1 km resolution using a process model named boreal ecosystem productivity simulator (BEPS). The model is driven by remotely sensed leaf area index and land cover maps as well as soil water holding capacity and daily meteorological data. All the major ET components are considered: transpiration from vegetation, evaporation of canopy‐intercepted rainfall, evaporation from soil, sublimation of snow in winter and in permafrost and glacier areas, and sublimation of canopy‐intercepted snow. In forested areas the transpiration from both the overstory and understory vegetation is modeled separately. The Penman‐Monteith method was applied to sunlit and shaded leaf groups individually in modeling the canopy‐level transpiration, a methodological improvement necessary for forest canopies with considerable foliage clumping. The modeled ET map displays pronounced east‐west and north‐south gradients as well as detailed variations with cover types and vegetation density. It is estimated that for a relative wet year of 1996, the total ET from all Canada's landmass (excluding inland waters) was 2037 km3. If compared with the total precipitation of 5351 km3 based on the data from a medium range meteorological forecast model, the ratio of ET to precipitation was 38%. The ET averaged over Canadian land surface was 228 mm/yr in 1996, partitioned into transpiration of 102 mm yr−1 and evaporation and sublimation of 126 mm yr−1. Forested areas contributed the largest fraction of the total national ET at 59%. Averaged for all cover types, transpiration accounted for 45% of the total ET, while in forested areas, transpiration contributed 51% of ET. Modeled results of daily ET are compared with eddy covariance measurements at three forested sites with a r2 value of 0.61 and a root mean square error of 0.7 mm/day.
Sources and chemical character of dissolved organic carbon across an alpine/subalpine ecotone, Green Lakes Valley, Colorado Front Range, United States
Authors: Hood Eran , McKnight Diane M. , Williams Mark W.
Published: July 2003

We investigated how the source and chemical character of aquatic dissolved organic carbon (DOC) change over the course of the runoff season (May–November, 1999) in Green Lakes Valley, a high‐elevation ecosystem in the Front Range of the Colorado Rocky Mountains. Samples were collected on North Boulder Creek from four sites across an alpine/subalpine ecotone in order to understand how the transition from the lightly vegetated alpine to the forested reaches of the catchment influences aquatic DOC. Concentrations of DOC at the four sites peaked between 2.6 and 8.9 mg C L−1 on the ascending limb of the snowmelt hydrograph, with the higher concentrations at the two subalpine sites. Seasonally, the chemical fractionation of DOC showed that there was a large range (29–72%) in the fulvic acid content of DOC at the four sites, with the highest fulvic acid percentages on the ascending limb of the hydrograph. Yields of DOC at the two gauged sites ranged from 10 to 11 kg ha−1 over the season with between 45 and 50% of the yield occurring as fulvic acid DOC and the remainder as nonhumic material. The fluorescence properties of DOC from all four sites indicated that during peak runoff, DOC was derived primarily from terrestrial precursor material. However, seasonal changes in the fluorescence properties of fulvic acids at the highest elevation sites suggest that DOC derived from algal and microbial biomass in the lakes is a more important source of DOC above tree line during late summer and fall. We hypothesize that much of the autochthonous DOC production is a result of algal growth in alpine lakes. Further, comparison to a forested control catchment suggests that processes in the alpine reach of the catchment may alter both the amount and chemistry of DOC incident to the downstream subalpine aquatic system.
A mixed magnetohydrodynamic‐kinetic theory of low‐frequency waves and instabilities in stratified, gyrotropic, two‐component plasmas
Authors: Ferrière K. M. , André N.
Published: July 2003

We study low‐frequency waves and instabilities in collisionless plasmas characterized by a gyrotropic (P⟂ ≠ P∥) thermal pressure and embedded in a magnetized, stratified, and rotating environment. We consider only small‐scale perturbations (with a wavelength that is short compared with the stratification scale height), and we make the restrictive assumption that the equilibrium parameters are invariant along magnetic field lines. In addition, we focus on two‐component ion‐electron plasmas, deferring the treatment of multicomponent plasmas to a companion paper. Our approach is not pure magnetohydrodynamics (MHD) but instead a mixture of MHD and kinetics, insofar as all our equations are fluid except the equations of state for P⟂ and P∥, whose perturbed expression is deduced from the Vlasov equation. The emphasis of the paper is laid on the so‐called quasi‐interchange modes, i.e., the modes on which stratification has a significant impact. After showing that these modes consist of the Alfvén, slow, and mirror modes at nearly perpendicular wave vectors, we investigate the question of their stability in a nonrotating system.