bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of anthraquinones in cell cultures of Cinchona ‘Robusta’ by HPLC with photodiode array and mass spectrometry detection
Authors: Han Ying‐Shan , Hofte Bertil , der Heijden Robert van , Verpoorte Robert 
Published: September 2003

AbstractAn HPLC‐PAD‐ESI/MS method has been developed for the analysis of anthraquinones in cell cultures of Cinchona ‘Robusta’. Using a C18 column and gradient elution with a mobile phase system containing acetonitrile, water and triﬂuoroacetic acid, a satisfactory separation of both anthraquinone glycosides and aglycones in a crude dichloromethane extract could be obtained. Robustaquinone B was identiﬁed as a major anthraquinone in the extracts, and another ﬁve anthraquinones were tentatively identiﬁed from spectroscopic data. A number of minor unknown compounds were detected and were distinguished from the known anthraquinones. An isocratic system for the quantitative determination of robustaquinone B has also been developed. Copyright © 2003 John Wiley & Sons, Ltd.
Fast high‐performance liquid chromatographic analysis of naphthodianthrones and phloroglucinols from Hypericum perforatum extracts
Authors: Tolonen Ari , Hohtola Anja , Jalonen Jorma 
Published: September 2003

AbstractHypericum perforatum L. (St. John's Wort) has been used in modern medicine for treatments of depression and neuralgic disorders. An HPLC method with photodiode array detection for the rapid determination of the major active compounds, naphthodianthrones and phloroglucinols, has been developed. The method permits the determination of hypericin, protohypericin, pseudohypericin, protopseudohypericin, hyperforin and adhyperforin in an extract in less than 5 min. Good linearity over the range 0.5–200 µg/mL for hyperforin and 0.02–100 µg/mL for hypericin was observed. Intra‐assay accuracy and precision varied from 0.1 to 17% within these ranges. Lower levels of quantitative determination were 2 µg/mL for hyperforin and 0.5 µg/mL for hypericin, while detection limits were 0.1 and 0.02 µg/mL, respectively. Copyright © 2003 John Wiley & Sons, Ltd.
Determination of the triacylglycerol composition of coffee beans by reverse‐phase high‐performance liquid chromatography
Authors: Jham Gulab N. , Nikolova‐Damyavova Boryana , Viera Mirtes , Natalino Ricardo , Rodrigues Augusto Cezar 
Published: September 2003

AbstractReverse‐phase HPLC with refractive index and light scattering detectors in isocratic and gradient elution modes, respectively, was applied for the separation of the major triacylglycerols (TAG) in coffee lipids. Twelve TAG species could be identiﬁed and determined using a linear gradient of acetonitrile in dichloromethane: dichloroethane. The quantitative evaluation was based on the relative area percentages derived directly from a data‐station. The procedure was applied to determine the TAG composition of three types of coffee beans harvested in two coffee producing areas in Brazil and dried by two commonly used procedures. No signiﬁcant differences in the TAG compositions due to the type, origin and drying procedure were found. Copyright © 2003 John Wiley & Sons, Ltd.
Characterization of an unsaturated low‐density polyethylene
Authors: Smedberg A. , Hjertberg T. , Gustafsson B. 
Published: September 2003

AbstractThis study concerns a new group of low‐density polyethylenes (LDPEs)—unsaturated LDPE. The new LDPE is a copolymer between ethylene and 1,9‐decadiene and was polymerized in a commerical high‐pressure tubular reactor. The diene copolymerized with one double bond, leaving the other unreacted as a pendant side group. This yielded a copolymer containing a higher number of vinyl groups than ordinary LDPE. Fractionation of the copolymer and determination of the number of unsaturated structures in the different fractions by Fourier transform infrared spectroscopy revealed that the diene is homogeneously incorporated along the molar‐mass distribution curve. It is also possible to obtain copolymers with a varying vinyl content, without drastic changes in molar mass or molar‐mass distribution, by a controlled addition of 1,9‐decadiene to the reactor. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2974–2984, 2003
Synthesis and properties of biodegradable copolymers based on 4,4′‐(adipoyldioxy)dicinnamic acid, 1,6‐hexanediol, and poly(ethylene glycol)s
Authors: Nagata Minoru , Hizakae Sigeki 
Published: September 2003

Abstract4,4′‐(Adipoyldioxy)dicinnamic acid (CAC) was synthesized by a condensation of adipoyl chloride and 4‐hydroxycinnamic acid. The CAC6 copolymers were prepared by a high‐temperature solution polycondensation of a diacyl chloride of CAC, 1,6‐hexanediol (6), and poly(ethylene glycol) (PEG) in which the molecular weights of PEG are 1000, 2000, and 8300. Differential scanning calorimetric curves of the copolymers exhibited a glass‐transition temperature because of PEG moiety and two melting endotherms (Tm's); the one at the higher Tm was due to CAC6 moiety, and the other at the lower Tm was due to PEG moiety, suggesting that these copolymers are the block type. The incorporation of the PEG component decreased the tensile strength and initial modulus, but increased the elongation extremely. The enzymatic degradation was performed in phosphate buffer solution (pH 7.2) with Ps. cepacia lipase at 37 °C. The degradation rate of the copolymers increased significantly with an increasing content of PEG, which was correlated to the water absorption of the copolymers. All copolymers could undergo photocuring by ultraviolet (UV) light irradiation (λ > 280 nm) at ambient temperature, as examined by UV spectroscopy and solubility. The CAC6/E2000(50/50) film photocured for 3 min exhibited a good elastic property with a maximum tensile strength of 3.7 MPa and maximum elongation of 640%. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2930–2938, 2003
Synthesis and cleavage of core‐labile poly(alkyl methacrylate) star polymers
Authors: Kilian Lars , Wang Zhen‐He , Long Timothy E. 
Published: September 2003

AbstractCore‐cleavable star polymers were synthesized by the coupling of living anionic poly(alkyl methacrylate) arms with either dicumyl alcohol dimethacrylate (DCDMA) or 2,5‐dimethyl‐2,5‐hexanediol dimethacrylate (DHDMA). This synthetic methodology led to the formation of star polymers that exhibited high molecular weights and relatively narrow molecular weight distributions. The labile tertiary alkyl esters in the DCDMA and DHDMA star polymer cores were readily hydrolyzed under acidic conditions. High‐molecular‐weight star polymer cleavage led to well‐defined arm polymers with lower molecular weights. Hydrolysis was confirmed via 1H NMR spectroscopy and gel permeation chromatography. Thermogravimetric analysis (TGA) of the star polymers demonstrated that the DCDMA and DHDMA star polymer cores also thermally degraded in the absence of acid catalysts at 185 and 220 °C, respectively, and the core‐cleavage temperatures were independent of the arm polymer composition. The difference in the core‐degradation temperatures was attributed to the increased reactivity of the DCDMA‐derived cores. TGA/mass spectrometry detected the evolution of the diene byproduct of the core degradation and confirmed the proposed degradation mechanism. The DCDMA monomer exhibited a higher degradation rate than DHDMA under identical reaction conditions because of the additional resonance stabilization of the liberated byproduct, which made it a more responsive cleavable coupling monomer than DHDMA. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3083–3093, 2003
Topological polymer chemistry by electrostatic self‐assembly
Authors: Tezuka Yasuyuki 
Published: September 2003

AbstractRecent developments in topological polymer chemistry are outlined. First, nonlinear polymer topologies are systematically classified on the basis of topological considerations of constitutional isomerism in a series of alkanes (CnH2n+2), monocycloalkanes (CnH2n), and polycycloalkanes (CnH2n−2, CnH2n−4, etc.). Various pairs of topological isomers are identified in randomly coiled, flexible polymer molecules with cyclic and branched structures. An electro‐ static self‐assembly and covalent fixation strategy has subsequently been developed for the efficient synthesis of a variety of topologically unique polymers, including monocyclic and polycyclic polymers, topological isomers, and topological block copolymers. In this process, new telechelics with moderately strained cyclic onium salt groups carrying multifunctional carboxylate counteranions have been designed as key polymeric precursors. Further extensions of topological polymer chem‐ istry have been achieved by the use of cyclic telechelics (kyklo‐telechelics) and cyclic macromonomers, obtainable also by means of the electrostatic self‐assembly and covalent fixation process. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2905–2917, 2003
The Jackknife applied to incomplete blood sampling models
Authors: Singer Júlia , Berger Marion 
Published: September 2003

AbstractA nonparametric alternative to the extended parametric Satterthwaite method taking into account the correlation between samples obtained from the same animal is presented. Confidence intervals are computed using a modified jackknife standard error. The performance of the method is studied by means of simulation. This nonparametric method has a smaller coverage rate than the parametric one, but still close to the nominal confidence level. In addition, its confidence interval is shorter than that of the parametric method using the generalized Satterthwaite approximation. Copyright © 2003 John Wiley & Sons, Ltd.
A fixed sequence Bonferroni procedure for testing multiple endpoints
Authors: Wiens Brian L. 
Published: September 2003

AbstractA method for controlling the familywise error rate combining the Bonferroni adjustment and fixed testing sequence procedures is proposed. This procedure allots Type I error like the Bonferroni adjustment, but allows the Type I error to accumulate whenever a null hypothesis is rejected. In this manner, power for hypotheses tested later in a prespecified order will be increased. The order of the hypothesis tests needs to be prespecified as in a fixed sequence testing procedure, but unlike the fixed sequence testing procedure all hypotheses can always be tested, allowing for an a priori method of concluding a difference in the various endpoints. An application will be in clinical trials in which mortality is a concern, but it is expected that power to distinguish a difference in mortality will be low. If the effect on mortality is larger than anticipated, this method allows a test with a prespecified method of controlling the Type I error rate. Copyright © 2003 John Wiley & Sons, Ltd.
Multimarker approach in transplanted mussels for evaluating water quality in Charentes, France, coast areas exposed to different anthropogenic conditions
Authors: Roméo M. , Mourgaud Y. , Geffard A. , Gnassia‐Barelli M. , Amiard J. C. , Budzinski H. 
Published: September 2003

AbstractAn active biomonitoring experiment was performed using mussels collected at a clean site, Fier d'Ars, and transplanted to two locations, outside the harbor of La Rochelle and in the Baie de L'Aiguillon along the coast of Charentes (French Atlantic coast) beginning in April for several months. Mussels were collected in June and October. The cadmium, copper, and zinc concentrations of all resident and transplanted mussel samples and the polycyclic aromatic hydrocarbon and polychlorinated biphenyl concentrations in some mussel samples and in the sediment samples were determined. Mussel response was evaluated for several biochemical biomarkers: concentrations of metallothionein, activities of glutathione S‐transferase and acetylcholinesterase (AChE) and levels of thiobarbituric reactive substance (TBARS). The physiological status of the animals was assessed using the condition index. A principal component analysis performed with the chemical and biochemical results of the evaluations of the resident and transplanted mussels collected in June allowed them to be separated into three groups: resident mussels from la Rochelle with high metal and TBARS levels, resident mussels from Baie de L'Aiguillon with a very high condition index, and resident mussels from Fier d'Ars and transplanted mussels at La Rochelle and Baie de L'Aiguillon with low TBARS and AChE activities. Strong seasonal variation from June to October of all parameters was noted. Mussels transplanted to La Rochelle appeared to be the most “polluted” in their pollutant concentrations and biochemical responses; moreover, the La Rochelle site had the highest concentration of organics in sediments of all the sites. The choice of Fier d'Ars as a reference site may be questionable because some of the biomarker responses of the mussels were higher than expected there, although these pollutants in mussels and sediment were present at the lowest concentrations measured. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 295–305, 2003.
PbCl2‐induced hyperpolarization of rat thymocytes: Involvement of charybdotoxin‐sensitive K+ channels
Authors: Nishizaki Yasutaka , Oyama Yasuo , Sakai Yoshiro , Hirama Seigo , Tomita Kazuyoshi , Nakao Hiromi , Umebayashi Chisato , Ishida Shiro , Okano Yoshiro , Carpenter David O. 
Published: September 2003

AbstractThe effect of PbCl2 on membrane potential and intracellular divalent metal cation concentrations of rat thymocytes was examined by flow cytometry. PbCl2 at concentrations of 0.3 μM or higher (up to 10 μM) produced persistent, dose‐dependent hyperpolarization (decrease in the intensity of di‐BA‐C4 fluorescence). Removal of external Ca2+ did not significantly affect the PbCl2‐induced hyperpolarization. Charybdotoxin, a specific antagonist of Ca2+‐dependent K+ conductance, greatly attenuated the PbCl2‐induced hyperpolarization. PbCl2 increased the intensity of fluo‐3 fluorescence under both normal Ca2+ and nominally Ca2+‐free conditions. These results suggest that Pb2+ enters thymocytes, causing an increase in fluo‐3 fluorescence, and activates Ca2+‐dependent K+ channels, resulting in hyperpolarization. The persistent activation of K+ channels by Pb2+, leading to persistent hyperpolarization, may be one mechanism whereby Pb2+ alters immune function, as membrane potential changes influence physiological functions of lymphocytes. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 321–326, 2003.
Comparative toxicity and biochemical responses of certain pesticides to the mature earthworm Aporrectodea caliginosa under laboratory conditions
Authors: Mosleh Yahia Y. , Ismail Saad M. M. , Ahmed Mohamed T. , Ahmed Yousery M. 
Published: September 2003

AbstractThis study was conducted to investigate the toxicity of aldicarb, cypermethrin, profenofos, chlorfluazuron, atrazine, and metalaxyl toward mature Aporrectodea caliginosa earthworms. The effects of the LC25 values of these pesticides on the growth rate in relation to glucose, soluble protein, and activities of glutamic‐oxaloacetic transaminase (GOT), glutamic‐pyruvic transaminase (GPT), acid phosphatase (AcP), and alkaline phosphatase (AIP) were also studied. The results showed that aldicarb was the most toxic of the tested pesticides, followed in order by cypermethrin, profenofos, chlorfluazuron, atrazine, and metalaxyl. A reduction in growth rate was observed in all pesticide‐treated worms, which was accompanied by a decrease in soluble protein and an increase in transaminases and phosphatases. Relationships between growth rate, protein content, transaminases, and phosphatases provided strong evidence for the involvement of pesticidal contamination in the biochemical changes in earthworms, which can be used as a bioindicator of soil contamination by pesticides. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 338–346, 2003.
Cyst‐based toxicity tests XV—Application of ostracod solid‐phase microbiotest for toxicity monitoring of contaminated soils
Authors: Chial Belgis , Persoone Guido 
Published: September 2003

AbstractA new “culture/maintenance‐free” microbiotest has recently been developed for “direct‐contact” toxicity determination of contaminated sediments. The 6‐day Ostracodtoxkit F™ makes use of the neonates of the ostracod crustacean Heterocypris incongruens hatched from dormant eggs (cysts). The new low‐cost assay has already been applied in three studies on river sediment from Flanders (Belgium) and from Canada and was found to perform comparably to the 10‐day Hyalella azteca and Chironomus riparius tests in detecting and quantifying sediment toxicity. Taking into account that sediments are in fact underwater soils, the ostracod microbiotest was tentatively applied on 15 contaminated soils from Flanders (Belgium), and its sensitivity (based on mortality as the test criterion) was evaluated in comparison to the 28‐day reproduction inhibition assay with the springtail Folsomia candida. The results revealed that the ostracod test species was as sensitive as or, in several samples, even more sensitive than the springtails. Leachate experiments on the same soil samples also showed that in most cases ostracod mortality was a result of the (nonsoluble) toxicants bound to the solid‐phase particles, rather than of those that had dissolved in the water phase. Providing confirmation of these first findings through additional studies, the new culture/maintenance‐free ostracod microbiotest seems to have good potential as a low‐cost and user‐friendly tool for routine toxicity monitoring of contaminated soils. © 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 347–352, 2003.
Evaluation of the exploitation of Eastern Baltic cod (Gadus morhua callarias L.) stock in 1976–1997
Authors: Radtke Krzysztof 
Published: September 2003

Abstract
Big changes occurred in the Eastern Baltic cod biomass and catches in the 1976–1997 period. At present, the Eastern Baltic cod stock spawning biomass (SSB) and catches are approximately five times lower than their highest ever recorded levels observed in the middle of the 1980s. The reasons for the stock decline, namely low recruitment and high fishing mortality, are widely known and well described in the literature. Throughout the whole period, the International Council for the Exploration of the Sea (ICES) made scientific recommendations regarding the exploitation level of the cod stock. The ICES presented and analysed different management strategies based on fishing mortalities which corresponded to biological reference points (BRP) and also recommended total allowable catches (TACs) for cod, taking into account the sustainability of cod resources. In fact, in most years the TAC established by the International Baltic Sea Fisheries Commission (IBSFC) and cod catches (observed exploitation) exceeded the ICES-recommended TAC and thus their scientific advice was neither taken into account by the IBSFC nor by fishermen.
This paper evaluates: (1) the would-be state of the Eastern Baltic cod stock if it had been exploited according to ICES-recommended TAC levels, as compared with observed stock exploitation; and (2) the potential effects of management using fishing mortality rates which correspond to BRP on SSB estimates and catch levels, as compared with observed stock exploitation.
It is concluded that if ICES advice had been followed, the cumulative cod catches in the 1976–1997 period would have been the same as those observed, but the stock biomass would have been much higher and at a safe level (SSB above 240 000 t).
Furthermore, from the comparative analysis of different management strategies based on BRP and the observed strategy, it appears that other management strategies could have been applied which would have produced a higher biomass and greater cumulative catch numbers than those observed.
Spatial and temporal patterns of cuttlefish (Sepia officinalis) abundance and environmental influences – a case study using trawl fishery data in French Atlantic coastal, English Channel, and adjacent waters
Authors: Wang Jianjun , Pierce Graham J , Boyle Peter R , Denis Vincent , Robin Jean-Paul , Bellido Jose M 
Published: September 2003

Abstract
The spatial and temporal distribution patterns of cuttlefish abundance and the relationships between cuttlefish abundance and environmental variables in the French Atlantic coast, the English Channel, and adjacent waters were studied using both geographical information system and statistical methods. Cuttlefish have a clear general annual migration pattern, consistently occurring in broadly the same areas in different years. The strength of the Atlantic currents into the west part of the English Channel and the south part of the Celtic Sea may be the dominant influence on the timing of cuttlefish migration to these areas. Local abundance shows a positive correlation with SST, although it is difficult to determine if this reflects any causal link. Cuttlefish expand their distribution further north in the spawning season in warm years and shift south in cool years. The centre of high abundance in offshore deep water shifts north in warm winters and south in cool winters.
Acoustic semi-tomography in studies of the structure and function of the marine ecosystem
Authors: Orlowski Andrzej 
Published: September 2003

Abstract
This paper describes a new, enhanced version of the macrosounding method. It was first introduced over 10 years ago by the author. The purpose was to integrate acoustic data with environmental and biological parameters in a time and space scale, for use in marine-ecosystem analyses. Previous visualizations were replaced in 2002 by a vari-coloured topographical space- or time-based matrix of fish volume-backscattering strength. The matrix is calculated from acoustic measurements, collected during the surveys for each elementary distance unit (ESDU) in standardized slices (depth intervals) of insonified volume (semi-tomography). Each sv visualization is accompanied by a cross-section of the same space unit, which provides a distribution of the selected environmental parameter measured during the same survey. Charts of such parameters are produced with the same procedures as for sv. This presentation of multidisciplinary data greatly improves recognition of time and space gradients. It exposes ecological inter-correlations that are difficult or impossible to estimate by numerical analysis of local diversity of the observed processes. The application of the method is illustrated by examples showing its practical use for data from 1994 to 2000 in the southern Baltic.
New indices in morphometry of nuclear structure in the NIH 3T3 cell line
Authors: Karalyan Z.A. , Djaghatspanyan N.G. , Gasparyan M.H. , Hakobyan L.A. , Abroyan L.O. , Magakyan Y.H. , Ter‐Pogossyan Z.R. , Kamalyan L.A. , Avagyan V.Y. , Karalova E.M. 
Published: September 2003

AbstractWe analyzed the connection of changes in nucleus ploidy with changes in nucleolar apparatus of NIH 3T3 cells. The quantity of nucleoli does not depend on the quantity of nucleolar DNA, but instead depends on euploidy: the majority of euploid cells have 1–3 nucleoli. The quantity of DNA in the nucleolus is correlated with the quantity of nucleolar DNA, and does not depend on ploidy changes. The nucleolar area has a tendency to increase in line with an increase in their numbers in the nucleus. The relationship of the quantity of DNA in the nucleolus with that of the nucleus is stable. During the process of increase in the number of nucleoli in a nucleus, there is a corresponding decrease in the quantity of DNA in each nucleolus, and there is likewise no increase in the sum of nucleolar DNA. The ratio of sums of the nucleolar perimeters to nuclear perimeter is a significant factor, which increases linearly along with an increase in the number of nucleoli in a nucleus.