bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Investigation into the Suitability of Bismuth as an Alternative to Gold‐Amalgam as a Working Electrode for the In Situ Determination of Chemical Redox Species in the Natural Environment
Authors: Waite Tim J. , Kraiya Charoenkwan , Trouwborst Robert E. , Ma Shufen , Luther George W. 
Published: May 2006

AbstractThe suitability of the bismuth film working electrode was investigated as an alternative to the gold‐amalgam electrode used in solid state microelectrodes for in situ voltammetric analysis of redox chemistry in the natural environment (e.g., lakes, oceans, sedimentary pore waters). Chemical redox species measurable with the Au‐amalgam include O2, H2S, S$ {_{{x}}^{2-}}$, S2O$\rm{ {_{3}^{2-}}}$, Fe2+, Fe3+, Mn2+, I−. Bismuth was electrochemically deposited to form a solid film analogous to the Au‐amalgam on a polished gold disk electrode. The useable potential window of the Bi‐film was found to be narrower than that of the Au‐amalgam, precluding the detection of dissolved O2, I− and S2O$\rm{ {_{3}^{2-}}}$, whose redox potentials fall outside the Bi‐film's range. The Bi‐film was able to detect free H2S/HS− and total sulfide (AVS), but not Fe2+ or Mn2+. The Bi‐film was less sensitive to low levels of total sulfide (<10 μM) than the Au‐amalgam; however, the Bi‐film was able to accurately quantify very high concentrations of sulfide (at least 15 mM), with a linear response up to an order of magnitude higher than that of the Au‐amalgam. Thus the Bi‐film appears to have limited application as an alternative to the Au‐amalgam microelectrode for in situ analysis of redox species in natural waters.
Overview on advances in capillary electrophoresis‐mass spectrometry of carbohydrates: A tabulated review
Authors: Campa Cristiana , Coslovi Anna , Flamigni Anna , Rossi Marco 
Published: May 2006

AbstractThe increasing interest for carbohydrates as holder of essential bioinformations has boosted their full characterization through analytical techniques. The intent of this review is to summarize the recent trends regarding on‐line and off‐line CE‐MS coupling for carbohydrate analysis. A statistical survey on the articles that use derivatizing agents as well as on the analyzer and type of instrument coupling (i.e. on‐ or off‐line) is depicted. From a general overview it can be concluded that, whereas derivatization might be useful for the detection of neutral carbohydrates improving separation selectivity with volatile buffers and increasing sensitivity of the MS detection, relatively few works with derivatized carbohydrates were found; this was noticed in particular for glycosides and saccharides carrying ionizable groups, which are normally analyzed without any chemical modification. The most applied coupling is the on‐line sheath‐liquid interface; for on‐line applications, ESI is the sole source used, whilst the most common analyzer is the IT. MSn is often exploited, as fragmentation increases the achieved structural information. CE‐MS turned out to be mainly used for the analysis of carbohydrates in drug development (i.e. study of oligosaccharides from pathogens, carbohydrate‐based drugs and drug metabolites), in nutrition and for characterization of glycans from glycoproteins. The reader will find elucidating tables regarding these recent CE‐MS applications, including the main information on the analysis conditions. Comments are meant to help the immediate focus on the usefulness of the analytical technique and predict the difficulties found during analysis and, in case, their overcoming.
A comparative study on intra‐articular versus systemic gene electrotransfer in experimental arthritis
Authors: Khoury M. , Bigey P. , Louis‐Plence P. , Noel D. , Rhinn H. , Scherman D. , Jorgensen C. , Apparailly F. 
Published: May 2006

AbstractBackgroundElectric pulse mediated gene transfer has been applied successfully in vivo for increasing naked DNA administration in various tissues. To achieve non‐viral gene transfer into arthritic joint tissue, we investigated the use of electrotransfer (ET). Because anti‐inflammatory cytokine strategies have proven efficient in experimental models of arthritis, we compared the therapeutic efficiency of local versus systemic delivery of the interleukin‐10 (IL‐10) using in vivo ET.MethodsA plasmid vector expressing IL‐10 was transferred into DBA/1 mouse knee joints by ET with 12 pulses of variable duration and voltage. The kinetics of transgene expression were analyzed by specific enzyme‐linked immunosorbent assay (ELISA) in sera and knees. Optimal conditions were then used to deliver increasing amounts of IL‐10 plasmid intra‐articularly (i.a.) in the collagen‐induced arthritis (CIA) mouse model. The therapeutic efficiency was compared with the potency of intra‐muscular (i.m.) ET.ResultsFollowing i.a. ET, local IL‐10 secretion peaked on day 7 and dropped 2 weeks after. A second ET produced the same kinetics without enhancing gene transfer efficiency, while transgene was still detected in injected muscles 4 weeks after ET. Only the i.m. ET of 25 µg of IL‐10 significantly inhibited all the clinical and biological features of arthritis. The i.a. ET only showed mild improvement of arthritis when 100 µg of IL‐10 plasmid were electrotransfered weekly from day 18 following arthritis induction.ConclusionsThe present results suggest that gene transfer into arthritic joints by ET is an effective means to deliver anti‐inflammatory cytokines. However, short duration of transgene expression impedes a significant effect for the treatment of arthritis, making i.m. ET more potent than i.a. ET for clinical benefit in CIA. Copyright © 2006 John Wiley & Sons, Ltd.
Die Innovation – Kleben – Aktuelles aus der “Arbeitsgruppe Kleben” des Fachverbandes Konstruktiver Glasbau – FKG
Authors: Hagl Anneliese 
Published: May 2006

AbstractWesentliche Motivation zur Gründung der Arbeitsgruppe war, daß sich Silikonverklebungen – im Bauwesen seit langem bekannt – in den vergangenen Jahren einen großen Einsatzbereich auf dem Gebiet der Fassadenverglasung erobert haben. Vorrangiges Einsatzgebiet war lange Zeit fast ausschließlich die Abdichtung von Wetterfugen und der Randverbund von Isolierglaseinheiten.Aufgrund seiner Eigenschaften bietet der Werkstoff Silikon das Potential, über die Dichtwirkung hinaus tragende Funktionen bei Fassadenkonstruktionen zu übernehmen. Eine Europäische Richtlinie (ETAG002) regelt derzeit die konstruktiven Randbedingungen von Silikonen für linienförmige Verklebungen. Trotzdem ist das Wissen bezüglich der tatsächlichen mechanischen Eigenschaften von Silikon noch begrenzt, so daß beim Einsatz von Verklebungen mit beliebiger Fugengeometrie in großem Maß auf Versuche zurückgegriffen werden muß. Wirkliche Werkstoffkennwerte und ‐gesetzmäßigkeiten, die ein ingenieurmäßiges Dimensionieren (Berechnen mit FEM) allgemeiner Fugengeometrien ermöglichen, sind zudem unbekannt. Der nach ETAG durchzuführende Zugversuch ist außerdem zur direkten Bestimmung der Festigkeitswerte von Silikon nur bedingt geeignet, da Randeffekte zur Spannungskonzentration in den Probekörpern führen und so Rückschlüsse auf das Festigkeitsverhalten des eigentlichen Werkstoffs nur eingeschränkt möglich sind.Das in der Arbeitsgruppe erarbeitete Versuchsprogramm dient dazu, durch das Zusammenspiel von Experiment (Werkstoffversuche) und Theorie (Nachrechnung mit FEM) theoretische Modelle für den Werkstoff Silikon zu entwickeln. Wesentliche Zielsetzung ist das Schaffen von Bemessungsdaten für komplexere Verklebungsgeometrien im Bereich des Structural Glazing.Durch das erlangte Wissen wird es künftig möglich sein:– Verklebungsgeometrien frei zu gestalten– sie hinsichtlich eines möglichst günstigen Versagensmechanismus zu optimieren– einfache Formeln und Kennwerte für den Entwurf beliebiger Verklebungen heranzuziehen– umfangreiche Versuche bei jeder einzelnen Anwendung einzuschränken bzw. zu vermeiden.Als Erweiterung des bisherigen Arbeitsprogramms ist vorgesehen, in Kürze auch Verklebungen mit Duromeren (z. B. Acrylate, Epoxidharze) zu untersuchen. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
S‐Adenosylhomocysteine hydrolase deficiency in a 26‐year‐old man
Authors: Buist N. R. M. , Glenn B. , Vugrek O. , Wagner C. , Stabler S. , Allen R. H. , Pogribny I. , Schulze A. , Zeisel S. H. , Barić I. , Mudd S. H. 
Published: May 2006

AbstractThis paper reports the third proven human case of deficient S‐adenosylhomocysteine (AdoHcy) hydrolase activity. The patient is similar to the only two previously reported cases with this disorder in having severe myopathy, developmental delay, elevated serum creatine kinase (CK) concentrations, and hypermethioninaemia. Although he has been followed from infancy, the basic enzyme deficiency was established only at age 26 years. The diagnosis was based on markedly elevated plasma concentrations of both AdoHcy and S‐adenosylmethionine, some 20% of the mean control activity of AdoHcy hydrolase activity in haemolysates of his red‐blood cells, and two missense mutations in his gene encoding AdoHcy hydrolase. He had low values of erythrocyte phosphatidylcholine and plasma free choline and marginally elevated excretion of guanidinoacetate, suggesting that the elevated AdoHcy may have been inhibiting methylation of phosphatidylethanolamine and guanidinoacetate. His leukocyte DNA was globally more methylated than the DNA's of his parents or the mean extent of methylation measured in age‐matched control subjects.
ON CONTINUOUS AND ADJOINT MORPHISMS BETWEEN NON-COMMUTATIVE PRIME SPECTRA
Authors: Letzter Edward S. 
Published: May 2006

AbstractWe study topological properties of the correspondence of prime spectra associated with a non-commutative ring homomorphism $R\rightarrow S$. Our main result provides criteria for the adjointness of certain functors between the categories of Zariski closed subsets of $\spec R$ and $\spec S$; these functors arise naturally from restriction and extension of scalars. When $R$ and $S$ are left Noetherian, adjointness occurs only for centralizing and ‘nearly centralizing’ homomorphisms.
A MULTIPLICITY THEOREM FOR A PERTURBED SECOND-ORDER NON-AUTONOMOUS SYSTEM
Authors: Faraci Francesca , Iannizzotto Antonio 
Published: May 2006

AbstractIn this paper we establish a multiplicity result for a second-order non-autonomous system. Using a variational principle of Ricceri we prove that if the set of global minima of a certain function has at least $k$ connected components, then our problem has at least $k$ periodic solutions. Moreover, the existence of one more solution is investigated through a mountain-pass-like argument.
Leaf processing in a woodland stream*
Authors: PETERSEN ROBERT C. , CUMMINS KENNETH W. 
Published: May 2006

SummaryDetritus processing by a small woodland stream is analysed by following the loss of weight of 10 g, single species accumulations of riparian leaves. The daily loss rates are expressed as exponential coefficients after the data are fitted by least squares. Comparisons are made between two sites on a small hardwater trout stream during two seasons. Leaf processing rates form a continuum from a low of 0.5%/day to a high of 2.0%/day. Differences between species of leaf are observed, but significant differences between fall and winter processing and between the two sites are not.The response of the invertebrate community to differences in leaf species is investigated using controlled, artificial streams where significant differences in the effect of the invertebrates are related to the ability ofthe leaf to be processed. Evidence suggests that differential invertebrate colonization of leaf packs is a function of microbial colonization and conditioning. The data are used to develop a general scheme of leaf pack processing.
The role of the littoral zone in the functioning of a shallow tropical lake ecosystem
Authors: HOWARD‐WILLIAMS C. , LENTON G. M. 
Published: May 2006

SummaryLake Chilwa (Malawi) is a shallow tropical lake surrounded by an extensive zone of littoral swamp mainly composed ofTypha domingensis. The data produced show that the physical and chemical conditions are different and more varied in the littoral region when compared with the open lake. Primary production in the littoral is confined almost entirely toTypha domingensis, which also acts as a nutrient pump by absorbing nutrients from the soils and eventually releasing them into the lake waters. Long term and short term exchanges in organic and inorganic materials between the littoral swamps and the open lake are described. These, as well as available evidence on the distribution, reproductive habits and diet of certain faunal groups, indicate that the littoral region of Lake Chilwa has an important regulating influence on the functioning of the whole lake.
Some effects of agricultural development and fluctuations in water level on the phytoplankton productivity and zooplankton of a New Zealand reservoir
Authors: MITCHELL S. F. 
Published: May 2006

SummaryIn Lake Mahinerangi, a New Zealand hydro‐electric supply reservoir, phytoplankton productivity increased from an annual average of 76 mg earbon m−2 day^−1 in 1964–66 to 210 mg carbon m−2 day−1 in 1968–70. It is likely that the increase was due partly to water levels being higher in 1968–70. Results of multiple regression analyses on the annual productivity curves for 1964–66 had suggested that water level, with temperature, was a major factor influencing the productivity at near‐optimal light intensity. In the interval between the two studies the first agricultural land‐development, amounting to 3% of the drainage basin, was carried out, and there is evidence that this development also contributed to the increase in phytoplankton productivity. Streams which drain the developed land were richer in phosphate and nitrate than the unmodified ones. Phosphate concentrations in the lake increased, but other chemical changes were slight. There were no major changes in the species composition of the phyto‐plankton. None of the three dominant species of zooplankton increased, but there were substantial increases in two less abundant taxa, Daphnia carinata King and Cyclopoida. The relative increase in Daphnia is consistent with the hypothesis that large zooplankton enjoy a competitive advantage over smaller species. Similar changes are noted from elsewhere.
Release of dissolved organic matter by photosynthesizing algae in Lake Kinneret, Israel*
Authors: BERMAN THOMAS 
Published: May 2006

SummaryThe incorporation of inorganic carbon in particulate and dissolved organic matter by natural populations of photosynthesizing algae has been studied in Lake Kinneret, Israel, from August 1972 to December 1973. The release of dissolved organic material was directly related to the rates of particulate productivity. However, the percentage of extracellular release (PER) of dissolved organic compounds showed an inverse relationship with chlorophyll a concentrations. Mean PER values (for the trophogenic layer) over the experimental period were 3·7%, and were lowest during the exponential growth phase of the annual dinoflagellate bloom (mean PER = 1·9%). Highest PER were measured in deep, light‐limited samples (mean = 31·7%; s.d.· 21·9%). In a dense metalimnic layer of photosynthetic sulphur bacteria (Chlorobium phaeobacterioides), PER was not as extremely high as has been reported for a similar layer in Lake Wadolek, Poland. Although the amounts of dissolved organic matter released by phytoplankton in Lake Kinneret were low, they may have significance as growth modulators and as substrates for heterotrophic organism.
Temperature studies on a river system in north‐east England
Authors: BOON P. J. , SHIRES S. W. 
Published: May 2006

SummaryA comprehensive temperature survey of the River North Tyne and its major tributaries is described. The maximum summer temperature of the main river increased downstream, and then remained more or less constant in the middle and lower reaches, whereas the minimum continued to rise throughout the length of the river. This general pattern was unaltered by flow rate, except in regions of almost stationary water. Mean water temperatures were low in winter, rose to a peak in July, and then fell during the remainder of the year. Throughout the year, three significantly different mean daily temperature ranges were demonstrated. The rate of change of temperature also varied seasonally, being greatest during July. A study of the major tributaries revealed certain differences, and these are discussed, particularly in relation to the importance of width and shading on water temperature. In conclusion, suggestions have been made concerning the possible influence of Kielder Water on downstream river temperatures.
Development of the mud habitat during the filling of two new lakes
Authors: McLACHLAN A. J. , McLACHLAN S. M. 
Published: May 2006

SummaryAn attempt is made to illustrate some of the principles of early development of muds in two contrasting lake basins which were devoid of vegetation cover before filling. Essentially the changes involve the dispersion and redistribution of particles in the newly flooded lake bottom. Field and laboratory observations are presented to demonstrate the interaction that exists between water chemistry, wave erosion and the burrowing activity of mud‐dwelling insect larvae, and the effect of these factors on particle size sorting in the substrate. These characteristic changes in the mud during filling are compared with post‐filling stage developments in which the role of extraneous material, including organic matter, may predominate.
Some effects of enclosure on the zooplankton in a small lake
Authors: SMYLY W. J. P. 
Published: May 2006

SummaryObservations on the effect of enclosure on zooplankton by introducing two experimental tubes, each holding some 18 000 m3 of water, into a small lake, showed that a limnetic community could be maintained within tubes of this capacity throughout a period of 22 months. Two species, the copepod Diaptomus gracilis and the cladoceran Daphnia hyalina were dominant both in the open lake and in each tube, but Diaptomus gracilis was relatively more abundant in the tubes than in the lake, whereas Daphnia hyalina, especially in spring and autumn, was more abundant in the lake than in the tubes. Several scarce species became relatively more abundant in the tubes than in the lake. These changes are more probably associated with reduced predation, especially by larvae of Chaoborus, than with artificially induced changes in the phytoplankton, changes only poorly correlated with changes in the zooplankton.
Radionuclide dating of the recent sediments of Blelham Tarn
Authors: PENNINGTON W. , CAMBRAY R. S. , EAKINS J. D. , HARKNESS D. D. 
Published: May 2006

SummaryLake sediments of the last 1000 years provide a unique record of environmental changes. Methods of dating this record are reviewed and discussed. Sediments of the last 20 years, which are of particular biological significance because of their record of man‐made changes in lakes (including enrichment and pollution) have been dated successfully by the distribution within them of the fallout product 137Cs, present in the atmosphere since 1954 and reaching a peak of supply in 1963. The structured pattern shown by the curve for 137Cs concentration in most sediments investigated indicates that faunal mixing of the surface muds does not destroy the vertical stratification of the sediment profile.Sediments up to 120 years old have been dated by a lead isotope technique, and the results of this proved consistent with both 137Cs dating and with palaeomagnetic dating where this was possible.Theoretical considerations of the application of radiocarbon dating to organic material of 18th and 19th century date are reviewed.Results of application of these radionuclide techniques to the sediments of a small lake, Blelham Tarn, near Windermere, are presented. Evidence from 137Cs and 210Pb dating of profiles from several different positions within the lake shows that the depth of the annual increment to the sediments varies by a factor of × 2 from place to place. The concentration within the sediment of chemical and biological variables shows no significant variation from one position to another; therefore calculated values for amounts of each variable included within unit area of the annual increment depend primarily on the thickness of this at the site chosen, and so cannot be directly related to the rates of supply of, for example, pollen grains or total organic matter, and so to rates of productivity.Results from nine 14C dates on material 400–1000 years old, when correlated with analyses for pollen and sediment composition, demonstrate the profound effects of agricultural practices in the catchment (assumed to be deforestation and ploughing) in disturbing the orderly transfer to lake sediments of material eroded from the catchment.
Dissolved organic matter of a low‐coloured stream
Authors: LARSON R. A. 
Published: May 2006

SUMMARY.
The dissolved organic matter (DOM) of White Clay Creek (Pennsylvania, U.S.A.), a low‐coloured stream, was characterized by gel permeation chromatography, humic acid determination, compound classification analysis and gas chromatography.Large polymers (approximate mol.wt above 5000) were virtually absent. The majority of the DOM consisted of fulvic acid‐like material, of probable mol.wt less than 3000. Highly coloured material represented only a small portion of the total. Substances classifiable as phenols, carbohydrates, lipids, amino acids or proteins made up only a small fraction of the DOM. Sixteen low mol. wt compounds (carboxylic acids, amino acids, carbohydrates and an amide) were tentatively identified.DOM concentration had a mean value of 6.4 mgC/l and showed annual fluctuations, with maxima in autumn and in late winter.
The biology of an Antarctic aquatic moss community
Authors: PRIDDLE J. , DARTNALL H. J. G. 
Published: May 2006

SUMMARY.
Two species of aquatic moss (Calliergon sarmentosum and Drepanocladus sp.) occur in deep water in Moss Lake, Signy Island (60° 43′S, 45° 38′W). Their elongate stems support a structurally complex community of epiphytic algae and associated invertebrates which has a greater diversity than the surrounding benthic algal communities.Qualitative differences in the distribution and abundance of the epiphytic algae are described. Two groups of algae present on both mosses are distinguished–‘habitual’ and ‘casual’ epiphytes. On Calliergun, algae are most abundant in the leaf axil. The succession of epiphytes down the stem and the progressive deterioration of the moss plant are used to characterize six stem zones.The invertebrates are benthic and most move actively among the moss. Six species of rotifers are more or less permanently attached and show a preference for the middle stem zones where epiphyte cover is highest. Four species favour the leaf axil, the other two colonize the bare underside of the leaf.A settlement experiment has shown the importance of wind‐induced mixing in summer for the transport of some epiphytic species from shallow parts of the lake. The settlement of sessile rotifers is effected by their larvae.Photosynthesis declines from the stem apex to the dead old stem. Much of the primary production of the community is algal. The respiration maximum occurs where the highest concentration of epiphytic algae and invertebrates is found.Interrelationships between the invertebrates and the epiphytic algae are suggested and a comparison is made between these data and other studies.