bluuebunny/crossref_metadata_2025_split huggingface dataset:
Schutzzielorientierte brandschutztechnische Bemessung für mehrgeschossige Gebäude
Authors: Hosser Dietmar , Zehfuß Jochen , Dehne Michael 
Published: July 2004

AbstractIn den meisten Ländern erfolgt die brandschutztechnische Bemessung bei mehrgeschossigen Gebäuden auf der Grundlage der Einheitstemperaturzeitkurve (ISO 834), die real zu erwartende Brände auf der sicheren Seite liegend abdecken soll. Eine Bemessung, die realistischere natürliche Brände und die Umlagerungsmöglichkeiten von Tragsystemen berücksichtigt, ist sowohl risikogerecht als auch wirtschaftlich. Ausgehend von internationalen Erfahrungen und Versuchsergebnissen sowie eigenen Forschungsarbeiten des iBMB wurden Bemessungsbrände und sog. Realbrandkurven entwickelt. Sie werden in Verbindung mit sog. allgemeinen Rechenverfahren (nach den Eurocodes) für die Simulation des Brandverhaltens von Tragsystemen genutzt. Ein probabilistisches Sicherheitskonzept gewährleistet die erforderliche Zuverlässigkeit der Brandschutzbemessung, wobei die Wahrscheinlichkeit der Brandentwicklung, die Bedingungen für den Personenschutz sowie die Unsicherheiten der Bemessungsparameter berücksichtigt werden.
Konsistente geometrische Ersatzimperfektionen für den numerisch gestützten Beulsicherheitsnachweis axial gedrückter Schalen
Authors: Schneider Werner 
Published: July 2004

AbstractEine geometrisch und materiell nichtlineare Analyse des imperfekten Schalentragwerks (GMNIA) ist die anspruchsvollste und perspektivisch wirklichkeitsnächste Methode des numerisch gestützten Beulsicherheitsnachweises stählerner Schalentragwerke. Von grundlegender Bedeutung sind bei diesem Nachweis die geometrischen Ersatzimperfektionen, die die Wirkung der verschiedenen Abweichungen von den Sollparametern auf der Widerstandsseite abdecken sollen. Die damit im Zusammenhang stehenden grundsätzlichen Probleme werden im Beitrag diskutiert. Der Eurocode gibt Hinweise für geometrische Ersatzimperfektionen und macht Angaben über anzusetzende Vorbeultiefen. Es wird dargestellt, daß mit den gegenwärtigen Regelungen noch nicht alle tragfähigkeitsrelevanten Imperfektionsparameter erfaßt sind und in manchen Geometriebereichen Inkonsistenzen zwischen den numerisch und experimentell ermittelten Beulwiderständen bestehen. Für den Basisbeulfall der axial gedrückten Schale werden Vorschläge unterbreitet, um konsistente geometrische Ersatzimperfektionen zu erhalten.
Zur Tragfähigkeit von Ankerplatten in bewehrtem Beton
Authors: Kuhlmann Ulrike , Imminger Thomas , Rybinski Markus 
Published: July 2004

AbstractZur Lasteinleitung in Betonbauteile werden häufig Ankerplatten mit angeschweißten Kopfbolzendübeln verwendet. Am Institut für Konstruktion und Entwurf wurden zwei Versuchsreihen an bewehrten Stahlbetonbauteilen durchgeführt, die zeigen, daß Bewehrung auf die Tragfähigkeit großen Einfluß hat und die tatsächlich übertragbaren Lasten rechnerisch bisher eher unterschätzt werden. Auf der Grundlage von 27 Versuchsergebnissen und ergänzenden FE‐Analysen wird ein erstes auf der Komponentenmethode basierendes mechanisches Modell vorgestellt, das die Tragfähigkeit von Ankerplatten mit angeschweißten Kopfbolzendübeln in bewehrten Stahlbetonbauteilen beschreibt.
MDMA‐evoked changes in cerebral blood flow in living porcine brain: Correlation with hyperthermia
Authors: Rosa‐Neto Pedro , Olsen Aage K. , Gjedde Albert , Watanabe Hideaki , Cumming Paul 
Published: July 2004

Abstract3,4‐Methylenedioxymethamphetamine (MDMA) acutely releases intraneuronal dopamine and serotonin and evokes hyperthermia which is linked to toxicity for serotonin fibers. The acute effects of MDMA on cerebral blood flow (CBF) in living brain have not been described in an animal model of MDMA intoxication. We predicted that MDMA‐induced hyperthermia should correlate with increased CBF in the hypothalamus, a serotonin‐rich brain region subserving thermoregulation. To test this prediction, we used positron emission tomography with statistical parametric mapping for exploratory analysis of the focal changes in the magnitude of CBF in the anesthetized female Landrace pig (n = 9) at 30 and 150 min after acute challenge with MDMA‐HCl (1 mg/kg, i.v.). The MDMA treatment was followed by increased CBF in the occipital cortex and in the medial mesencephalon overlapping the dorsal raphé nucleus, and reduced CBF in the cerebellar vermis and in a cluster in the medulla encompassing the left locus coeruleus. The individual increase of body temperature correlated positively with increased CBF in the vicinity of the raphé nucleus, in the hypothalamus (regions linked to thermoregulation), and also in the medial frontal cortex, which together comprise the regions receiving the most dense serotonin innervations in pig brain. Thus, individual differences in the susceptibility to MDMA‐induced hyperthermia in this population correlated with the magnitude of focal increases in CBF within specific brain regions endowed with a dense serotonin innervation, including regions linked to thermoregulation. Synapse 53:214–221, 2004. © 2004 Wiley‐Liss, Inc.
MDMA‐evoked changes in [11C]raclopride and [11C]NMSP binding in living pig brain
Authors: Rosa‐Neto Pedro , Gjedde Albert , Olsen Aage K. , Jensen Svend B. , Munk Ole L. , Watanabe Hideaki , Cumming Paul 
Published: July 2004

AbstractPositron emission tomography (PET) studies with radiolabeled dopamine D2‐like receptor ligands reveal d‐amphetamine‐evoked increases in the competition from endogenous dopamine. However, the corresponding effects of methylenedioxymethamphetamine (MDMA, “Ecstasy”), which releases catecholamines and also serotonin, are unknown. Using PET, we measured the binding potentials (pBs) of the benzamide [11C]raclopride and the butyrophenone N‐[11C]methylspiperone ([11C]NMSP) in brain of living pigs first in a baseline condition and at 45 and 165 min after infusion of (+/‐)‐MDMA‐HCl (1 mg/kg, i.v.). Concomitant studies of cerebral blood flow did not reveal significant perfusion changes in the cerebellum reference region or in striatum, supporting the present use of reference tissue methods for the mapping of MDMA‐evoked pB changes. Relative to the baseline pB of [11C]raclopride for dopamine D2/3 receptors in striatum (pB = 1.5–2.2), MDMA‐treatment reduced pB by 35% in the first posttreatment scan and by 22% in the second posttreatment scan, comparable to changes typically evoked by d‐amphetamine at a similar dose. In most previous studies, the in vivo binding of butyrophenones has been nearly insensitive to d‐amphetamine‐evoked dopamine release. However, we found the baseline pB of [11C]NMSP for dopamine D2‐like receptors in striatum (pB = 4–5) was decreased by 30% in the first post‐MDMA scan and by 50% in the second post‐MDMA scan, irrespective of assumptions about the extent of equilibrium binding attained during the 90‐min‐long PET recordings. Distinct properties of MDMA such as simultaneous release of dopamine and serotonin in brain may account for the present finding of progressive decline in the availability of [11C]NMSP binding sites in striatum. Synapse 53:222–233, 2004. © 2004 Wiley‐Liss, Inc.
Hormonelike effects of humic substances on fish, amphibians, and invertebrates
Authors: Steinberg Christian E. W. , Höss Sebastian , Kloas Werner , Lutz Ilka , Meinelt Thomas , Pflugmacher Stephan , Wiegand Claudia 
Published: July 2004

AbstractHumic substances comprise the majority of organic matter in freshwater ecosystems and were thought to be inert or refractory, except for photolytic degradation. However, evidence is increasing that humic substances interact with aquatic organisms similarly to weak anthropogenic chemicals with nonspecific and specific effects. One specific effect is a hormonelike effect, namely, modulation of the number of offspring, which was first described with the nematode Caenorhabditis elegans. Yet a hormonelike effect is not restricted to only the nematode. With the ornamental swordtail fish, Xiphophorus helleri, and the South African clawed frog, Xenopus laevis, we present phenomenological evidence that slight feminization occurred when these vertebrate species were exposed to a synthetic humic substance, a condensation product of polyphenols. The slight feminization was dose dependent. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 409–411, 2004.
Comparison of 17 biotests for detection of cyanobacterial toxicity
Authors: Maršálek Blahoslav , Bláha Luděk 
Published: July 2004

AbstractThe aim of the present study was to compare the sensitivity of 17 acute bioassays of cyanobacterial toxicity by assessment of crude extracts of three cyanobacterial samples (all dominated by Microcystis sp. but substantially differing in microcystin‐LR content). Toxicity of the fractions prepared by solid‐phase extraction (SPE) for microcystins was also determined. The most sensitive bioassay was the 24‐h test with crustacean Thamnocephalus platyurus, which elicited high lethality in the samples and also in fractions without microcystins. The fruit fly Drosophila melanogaster, protozoans Spirostomum ambiguum and Tetrahymena termophyla, and the crustacean Daphnia pulex formed the second group of sensitive bioassays. Good selective toxicity response to microcystins also was observed in the weakly sensitive biotests with the oligochaete Tubifex tubifex and the rotifer Brachionus calyciflorus. Preconcentration of microcystins by SPE substantially decreased variation of the results in bioassays and improved the discriminating potential of most assays employed. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 310–317, 2004.
Effect of lead and chromium on reproductive success of Japanese quail
Authors: Butkauskas D. , Sruoga A. 
Published: July 2004

AbstractAn experimental model based on application of Japanese quail (Coturnix coturnix japonica) lines with high (H) and low (L) concentrations of plasma lactate was designed in order to investigate the effects of lead and chromium on embryonic development and reproductive success of experimental groups representing different genotypes. During the first stage of the trial, mature males from quail lines H and L (marked as generation T) were fed subchronically for 12 weeks with lead as Pb(NO3)2 and chromium as K2Cr2O7 (dosage 0.8 and 0.142 g/kg, respectively, in the feed). In addition, a binary mixture of both lead and chromium was administered to the third group of males. The control group consisted of untreated birds. After mating with untreated females (8 ♀ × 5 ♂ in each group), progeny with four genotypes were obtained. The chicks were marked as generation F1 and used in the second stage of the trial. The data obtained show that heavy metals decreased the hatchability of sexually mature quail males: chromium (14%), lead (19%), and binary lead–chromium mixture (28%). Early embryonic mortality increased as much as 2–3 times. Single lead and binary lead‐chromium additions decreased fertility after treating Japanese quail during the development of sexual maturity: lead increased the number of unfertile eggs up to 30% (twofold), binary lead and chromium, up to 50% (more than threefold) relative to untreated controls. There was no effect of chromium alone on fertility. In general, hatchability, fertility, embryonic mortality and reproductive success of Japanese quail were dependent on age, sex, genotypes, and on single or binary treatment with the inorganic salts of lead and chromium. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 412–415, 2004
Spirotox—Spirostomum ambiguum acute toxicity test—10 years of experience
Authors: Nałęcz‐Jawecki Grzegorz 
Published: July 2004

AbstractSpirotox is a short‐term acute toxicity test with a large ciliated protozoan Spirostomum ambiguum. The test was created in the Department of Environmental Health Sciences, Medical University of Warsaw, Poland, during the early 1990s. It was presented for the first time during the 6th International Symposium on Toxicity Assessment, in Berlin in 1993. S. ambiguum was very resistant to a wide range of environmental conditions, especially to pH and dissolved oxygen. Over the last 10 years the sensitivity of S. ambiguum to many classes of toxicants was evaluated. Spirotox was found to be very sensitive to heavy metals, fungicides, and pharmaceuticals used to cure diseases of the human nervous system. On the other hand, it was generally less sensitive than standard bioassays to simple organics. Spirotox was also used for analysis of cyanobacterial blooms. Though it was moderately sensitive to hepatotoxins, the test seems to be a good tool for evaluation of the entire toxicity of blooms. The last but not the least of the applications of the Spirotox test was evaluation of the toxicity of extracts from medical devices. Protozoa, which are the simplest eukaryotes, seem to be good screening bioassays for monitoring the technology of medical device production. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 359–364, 2004.
Defense systems of benthic invertebrates in response to environmental stressors
Authors: Vasseur P. , Leguille C. 
Published: July 2004

AbstractEnvironmental stress factors may be responsible for biological changes in living species that are able to overcome deleterious effects depending on their detoxifying capacities. Defense systems present in every living species are involved in elimination of reactive chemical species of endogenous or exogenous origin, neutralization of their effects, repair of initial lesions, and compensation of deficient metabolic pathways. Consequently, the performance of defense systems and their inducibility will explain adaptation to environmental disturbances, whereas their alteration will augur toxicity in the exposed species. Several field studies have illustrated the relationships between antioxidants and toxicity in benthic invertebrates in rivers. They highlighted that defense systems may be useful biomarkers in mechanistic studies of ecotoxicity and in the biomonitoring of living species in polluted environments. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 433–436, 2004
Toxicity assessment of wastewaters, river waters, and sediments in Austria using cost‐effective microbiotests
Authors: Latif Muna , Licek Elisabeth 
Published: July 2004

AbstractThe toxicity and chemical quality of surface water and sediment in the River Traun in Austria were studied because of recurrent fish mortality in some alpine rivers over the last few years. The analyses were carried out on samples collected during winter and summer upstream and downstream of two municipal wastewater treatment plants (WWTPs) and on effluents taken at the points of discharge of these two plants. Toxicity tests were performed on 20 samples of surface water, effluent, and sediment pore water. The test battery was composed of microbiotests with protozoans (Protoxkit F™), microalgae (Algaltoxkit F™), crustaceans (Daphtoxkit F™ magna and Thamnotoxkit F™), and a higher plant (seed germination and root elongation assay on cress). Direct contact tests were performed on whole sediment with crustaceans (Ostracodtoxkit F™). The physical‐chemical characteristics of the surface water, effluent, and sediment pore water samples analyzed were conductivity, total hardness, pH, O2, BOD5, TOC, DOC, AOX, NH4, NH3, NO2, PO4P, Cd, Pb, Cu, and Zn. The toxicity data were expressed as percentage mortality or percentage inhibition, depending on the effect criterion of the respective assay. None of the water samples collected upstream and downstream of the WWTPs showed any significant (short‐term) toxicity in either winter or in summer, but the effluents of the first municipal wastewater treatment plant were toxic to some of the test biota. All the sediment pore water samples induced serious inhibition of root growth of cress, and several pore waters were toxic to other test biota as well, particularly at the outlets of the WWTPs. The toxic character of some sediments was confirmed by direct contact tests with the ostracod crustacean. The chemical analyses did not reveal particularly high concentrations of any chemical that is very toxic. As a result no direct causal relationship could be established between the detected toxic effects and the chemical composition of the surface waters or sediment pore waters. The outcome of this preliminary study again highlights the need to complement chemical analyses with toxicity tests to determine the toxic hazard to aquatic environments that may be threatened by contamination. Furthermore, the investigations also confirmed the need to apply a battery of tests for an ecologically meaningful evaluation of the hazards of waters, sediments, and wastewaters. Finally, the results of the 360 bioassays performed show that culture‐independent microbiotests are practical and reliable tools for low‐cost toxicity monitoring of aquatic environments. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 302–309, 2004.
Physical and chemical aspects of long‐term biodeterioration of some polymers and composites
Authors: Lugauskas A. , Prosychevas I. , Levinskaitė L. , Jaskelevičius B. 
Published: July 2004

AbstractA biodeterioration study was performed on synthetic polymeric materials including homogenous film made from poly(tetrafluorine ethylene), copolymer film made from tetrafluorine ethylene and perfluoromethyl vinyl ether, vulcanized rubber containing natural caoutchouc, and vulcanized rubber, the main component of which was synthetic butadiene nitrile caoutchouc. The materials were exposed for 12 years to the open air, in mycological containers, and in a cellar in maritime climate conditions: air humidity 72%–90% and seasonal average temperature of 17°C in summer and −2.5°C in winter. The studies of optical and electron microscopy revealed that microorganisms were able to develop not only on the surface of the materials but also to penetrate inside into deeper layers. The fungi that produced the most intensive deterioration in the fluorine polymers and vulcanized rubbers belonged to the Alternaria, Aspergillus, Aureobasidium, Cladosporium, Penicillium, Oidiodendron and Trichoderma genera. The fungi Aspergillus fumigatus, A. niger, Aureobasidium pullulans, and Trichoderma viride produced the most intensive deterioration in the fluorine films, whereas Alternaria tenuissima, Cladosporium herbarum, C. sphaerospermum, and fungi of the Oidiodendron genus were widespread on vulcanized rubbers. Fungi of the Aspergillus and Penicillium genera prevailed on both fluorine films and rubbers exposed in a cellar. Infrared spectroscopy indicated that the structures of poly(tetrafluorine ethylene) and the copolymer of tetrafluorine ethylene and perfluoromethyl vinyl ether did not change after the 12‐year exposure; only insignificant changes in surface morphology were observed by optical microscopy. Vulcanized rubber made both from natural and from synthetic caoutchouc exposed for the same length of time showed rather evident changes in appearance and structure. X‐ray graphical analysis revealed that new crystallization of the caoutchouc and a possible change in chemical composition of the fillers had occurred. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 318–328, 2004.
Impact of crude oil on bacteriocenosis of the digestive tract of mollusks
Authors: Šyvokienė J. , Mickėnienė L. 
Published: July 2004

AbstractIn this study the effect of crude oil on intestinal bacterial populations of the mollusk Viviparus contactus was investigated. The addition of crude oil into an environment of mollusks induced no clear changes in the saprophytic, amylolytic, and total coliform bacterial counts in the digestive tract of the mollusk. After 10 days of contamination, the saprophytic, amylolytic, and total coliform bacterial numbers were of the same order of magnitude as the initial numbers. Significant numbers of indigenous hydrocarbon‐degrading bacteria were observed in the intestinal tracts of mollusks before contamination with crude oil. Introduction of crude oil into the mollusk environment resulted in an increase of 2 orders of magnitude in the number of hydrocarbon‐degrading bacteria in the digestive tract. Therefore, measuring the hydrocarbon‐degrading bacterial populations in the digestive tracts of hydrobionts can be considered an important component of contaminated‐site assessment studies. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 421–424, 2004.
Acute toxicity investigations of ester‐based lubricants by using biotests with algae and bacteria
Authors: Michel K. , Brinkmann C. , Hahn S. , Dott W. , Eisentraeger A. 
Published: July 2004

AbstractAlthough ester‐based lubricants are ecologically acceptable due to their good biodegradability, there are still some environmental ecotoxicological impacts that have to be considered. Information on the acute ecotoxicological behavior of lubricants is obtained in this work using several single species bioassays. In previous studies it was observed that lubricating fluids containing additives for the enhancement of their technical performance were more problematic than base fluids especially with respect to algae growth inhibition. In order to clarify the influence of additives, the anti‐wear additive tri‐n‐butyl phosphate was tested. It was very toxic to algae though not to bacteria. Additionally, a mixture of this additive with a base fluid is characterized. Despite the high toxicity of the single additive, the water extract of the mixture of tri‐n‐butyl phosphate with hydraulic base fluid caused almost no toxicity. Therefore, tri‐n‐butyl phosphate cannot explain the effect observed for the toxicity of water extracts of the commercially available lubricants. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 445–448, 2004.
Were volatile organic compounds the inducing factors for subjective symptoms of employees working in newly constructed hospitals?
Authors: Takigawa Tomoko , Horike Tokushi , Ohashi Yasuhiro , Kataoka Hiroyuki , Wang Da‐Hong , Kira Shohei 
Published: July 2004

AbstractThis study demonstrated possible relationships between environmental, personal, and occupational factors and changes in the subjective health symptoms of 214 employees after the relocation of a hospital in a region of Japan. Eight indoor volatile organic compounds (VOCs) were detected in at least one of the 19 rooms investigated, and total VOC (TVOC) concentrations in 8 rooms exceeded the advisable value (400 μg/m3) established by the Ministry of Health, Labour and Welfare of Japan. Formaldehyde was detected in all the investigated rooms, but none of the results exceeded the guideline value (100 μg/m3). Multiple logistic regression analysis was applied to select variables significantly associated with the subjective symptoms that can be induced by sick building syndrome. The results showed that subjective symptoms of deterioration in the skin, eye, ear, throat, chest, central nervous system, autonomic system, musculoskeletal system, and digestive system among employees were associated mainly with gender difference and high TVOC concentrations (>1200 μg/m3). Long work hours (>50 h per week) in females and smoking in males were to be blamed for the deterioration of their symptoms. The present findings suggest that to protect employees from indoor environment‐related adverse health effects, it is necessary to reduce the concentration of indoor chemicals in new buildings, to decrease work hours, and to forbid smoking. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 280–290, 2004.