bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tropical ecotoxicity testing with Ceriodaphnia cornuta
Authors: Hong Lan Chi Do , Becker‐Van Slooten Kristin , Tarradellas Joseph 
Published: September 2004

AbstractThe Sai Gon–Dong Nai river system in southern Vietnam is of great social and economic importance yet receives a large amount of industrial, domestic, and agricultural discharges. Toxicity assessment has started to become an issue in Vietnam, and it is important to employ a test system that is appropriate for typical Vietnamese conditions with a species that is representative of the invertebrates living in its aquatic ecosystems. The aim of this study was to develop and to validate an ecotoxicity test with an autochthonous organism. The microcrustacean Ceriodaphnia cornuta (Cladocera) was isolated from the Sai Gon River. A protocol was developed for the culturing of the organisms, and satisfactory results were obtained for long‐term reproduction of C. cornuta. Quality control criteria were established. The toxicity of two relevant pesticides (diazinon and methyl parathion) and two metals (chromium and mercury) to C. cornuta was evaluated and compared to the standard organisms for ecotoxicological testing: Daphnia magna and Vibrio fischeri. Nonlinear regression models were applied to estimate such parameters as EC50. The results of acute toxicity tests showed that C. cornuta was less tolerant than D. magna and V. fischeri to salinity and that C. cornuta was more sensitive than D. magna and V. fischeri to potassium dichromate, diazinon, methyl parathion, and mercury. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 497–504, 2004.
In vitro androgenicity in pulp and paper mill effluents
Authors: Svenson Anders , Allard Ann‐Sofie 
Published: September 2004

AbstractPulp and paper mill effluents were examined for in vitro androgenicity using a recombinant yeast‐based androgen receptor assay. Low levels of androgenic effects were detected in extracts of some effluents after activated sludge treatment. Yeast cell growth cell was inhibited in some samples, and this interfered with the androgenic response. Solid‐phase fractionation revealed androgenicity after partial separation of components in the effluents. Comparison of levels in untreated effluent and in effluent treated in an aerated lagoon showed that this treatment had only a marginal effect on androgenicity. An assay of the fractions eluted with increasing concentrations of methanol showed that androgenic compounds were low to moderately lipophilic. In an attempt to identify these compounds, a number of wood‐related compounds (guaiacol, vanillin, β‐sitosterol, betulin, pinosylvin‐O‐methyl ether, and a wood extract enriched in lignans) were examined but were found not to be androgenic. Raw process water was not androgenic, but water from a highly humified lake and process water from the production of pulp from partly decayed wood had low androgenicity. It therefore can be plausibly suggested that the androgens originated in decaying wood. An assay of androgenicity in the bile of juvenile rainbow trout exposed to effluents for 3 weeks showed increased dose‐dependent levels of androgens after enzymatic hydrolysis of hormone conjugates. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 510–517, 2004.
Acute changes of cerebral venous blood flow in growth‐restricted human fetuses in response to uterine contractions
Authors: Li H. , Gudmundsson S. , Olofsson P. 
Published: September 2004

AbstractObjectiveThe fetal cerebral venous circulation during acute hypoxic stress provoked by uterine contractions has not been studied previously. The aim of this study was to explore the cerebral venous circulation during an oxytocin challenge test (OCT) in intrauterine growth‐restricted (IUGR) fetuses.MethodsDoppler recordings of blood flow in the vein of Galen (GV), straight sinus (SS) and transverse sinus (TS) before and during uterine contractions and relaxation were obtained at the same time as electronic fetal heart rate (FHR) monitoring in 44 term IUGR fetuses. The OCT was classified as negative (normal FHR) or positive (late FHR decelerations). Non‐parametric statistics were used to test differences between OCT groups.ResultsIn OCT‐negative cases (n = 39), de novo pulsations occurred in the GV, and SS flow velocities increased during contractions compared with basal measurements. There were no significant differences in TS flow. Flow recordings were less often obtained from OCT‐positive cases (n = 5), making comparisons with OCT‐negative cases uncertain.ConclusionsIn uncompromised IUGR fetuses an acute cerebral venous hyperperfusion develops in response to uterine contractions. Pulsations in the GV are detected but are unlikely to be an ominous sign in this situation. The more centrally located TS was less discriminating for acute cerebral venous blood flow changes. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
Effect of additive interactions on the thermo‐oxidative stabilization of a film grade metallocene LLDPE
Authors: Hoàng Eric M. , Liauw Christopher M. , Allen Norman S. , Fontán Eusebio , Lafuente Pilar 
Published: September 2004

AbstractThe simultaneous effects of a range of additives and associated interactions on melt processing stability, processing discoloration, and long‐term stability of a blown film‐grade metallocene LLDPE (mLLDPE) were investigated by using a two‐level factorial experimental design. The additives investigated were a phenolic antioxidant, a phosphite processing stabilizer, a calcium stearate antacid, a synthetic silica antiblocking agent, and an erucamide slip additive. A multiple extrusion experiment was carried out to assess processing stability. Melt stabilization performance was monitored by melt flow rate (MFR) measurements, and color development was determined using yellowness index (YI) measurements. Long‐term thermal stability was assessed by monitoring the rate of formation of the non‐volatile carbonyl oxidation products using FTIR. Results were quite consistent with the literature. Therefore, the two‐level factorial experimental design proved to be a very useful tool for screening the simultaneous effects of each additive and the possible interactions between additives present in the stabilizer system investigated. J. Vinyl Addit. Technol. 10:149–156, 2004. © 2004 Society of Plastics Engineers.
On the effect of user mobility and density on the performance of protocols for ad‐hoc mobile networks
Authors: Chatzigiannakis Ioannis , Kaltsa Elena , Nikoletseas Sotiris E. 
Published: September 2004

AbstractIn this paper, we demonstrate the significant impact of (a) the mobility rate and (b) the user density on the performance of routing protocols in ad‐hoc mobile networks. In particular, we study the effect of these parameters on two different approaches for designing routing protocols: (a) the route creation and maintenance approach and (b) the ‘support’ approach that forces few hosts to move, acting as ‘helpers’ for message delivery. We study one representative protocol for each approach, i.e. AODV for the first approach and RUNNERS for the second. We have implemented the two protocols and performed a large scale and detailed simulation study of their performance. The main findings are: the AODV protocol behaves well in networks of high user density and low mobility rate, while its performance drops for sparse networks of highly mobile users. On the other hand, the RUNNERS protocol seems to tolerate well (and in fact benefit from) high mobility rates and low densities. Copyright © 2004 John Wiley & Sons, Ltd.
A unifying look at clustering in mobile ad hoc networks
Authors: Wang Lan , Olariu Stephan 
Published: September 2004

AbstractIn recent years, a significant number of clustering schemes have been proposed in the literature. Most of them treat cluster initialization and cluster maintenance differently as if they were two entirely different undertakings. The main contribution of this work is a unifying way of looking at clustering in MANET. We make an important point: there is no difference between cluster initialization and cluster maintenance, and one algorithm should gracefully blend into the other. To illustrate the feasibility of this concept, we propose a novel tree‐based clustering algorithm for MANET based on a number of properties of diameter‐2 graphs. The algorithm is cluster‐centric and, unlike the vast majority of algorithms in the literature, works in the presence of node mobility. Extensive simulation results show the effectiveness of our algorithm when compared to other clustering schemes proposed in the recent literature. Copyright © 2004 John Wiley & Sons, Ltd.
Trace element categorization of pollution sources in the equator town of Nanyuki, Kenya
Authors: Gatari Michael , Boman Johan , Maina David 
Published: September 2004

AbstractAn air pollution campaign was carried out in the town of Nanyuki at four different sites during July and August 1999. Nanyuki is situated on the equator on the northwestern slope of Mount Kenya at about 1930 m above sea level. The intention of the project was to characterize aerosol elemental compositions in two size fractions, associated with specific natural and anthropogenic activities. A dichotomous impactor was used for sampling and an energy‐dispersive x‐ray fluorescence spectrometer was used for the analysis. Fourteen elements (Si, S, K, Ca, Ti, Mn, Fe, Cu, Zn, Ga, Br, Rb, Sr and Pb) were analysed in all the samples. The concentration of Pb was highest at a site in the vicinity of open‐air vehicle garages. The four sites recorded high concentrations of fine S, Cl and K. Fine Zn and Br were also measured at all the sites. In the coarse size range, the concentrations of soil‐derived elements (Si, K, Ca and Fe) were dominant. The high concentration of coarse Cl was considered to be due to the contribution of sea salt and that of S to be a contribution of gas to particle conversion of SO2. The two elements S and Cl signified the influence of long‐distance transported aerosols. The comparatively high concentrations of fine Pb and Br signified the high rate of vehicle repairs, which is a major activity close to one of the sites. Generally, soil dust‐derived particles and those from biomass burning dominated the town aerosols. Copyright © 2004 John Wiley & Sons, Ltd.
Semiempirical approach for standardless calibration in µ‐XRF spectrometry using capillary lenses
Authors: Padilla R. , Van Espen P. , Abrahantes A. , Janssens K. 
Published: September 2004

AbstractQuantitative µ‐XRF analysis based on standardless calibration is limited by the lack of information on the shape of the excitation spectrum resulting from using capillary lenses. The measurement of radiation scattered from a sample was used in combination with Monte Carlo simulation of radiation transport to estimate the energy spectral distribution of the excitation radiation. Further, a standardless calibration based on the fundamental parameter method implemented in the IAEA‐QXAS software package was carried out and verified for glass and fused ore certified reference materials. The accuracy and repeatability achieved are reported. Copyright © 2004 John Wiley & Sons, Ltd.
Health‐endangering behaviours among Japanese college students: a test of psychosocial model of risk‐taking behaviours
Authors: Omori Mika , Ingersoll Gary M. 
Published: September 2004

AbstractAdolescents’ health‐endangering behaviours receive attention because they are presumed to threaten the health of individuals in either the short or long term. The present study examined the role of psychosocial determinants on adolescents’ health‐endangering behaviours using elements of a biopsychosocial model proposed by Irwin and Millstein (1986). It was hypothesized that egocentrism, self‐esteem, and perceived social environment affect the onset of risk‐taking behaviours, mediating risk perception. Eight hundred and eight Japanese college students completed questionnaires. Results from a structural equation analysis partly supported the hypothesized model. Egocentrism contributes directly to health‐endangering behaviours while influences of self‐esteem and perceived social norms are mediated by risk perception.
Multiple clustered layer solutions for semilinear Neumann problems on a ball
Authors: Ni Wei-Ming , Wei Juncheng , Malchiodi A. 
Published: September 2004

We consider the following singularly perturbed Neumann problem

\begin{cases}
ɛ^{2}\mathrm{\Delta }u−u + f(u) = 0\:& \text{in}\:\Omega \text{;} \\
u > 0\:\text{in}\:\Omega \:\text{and}\:\frac{\partial u}{\partial \nu } = 0\:& \text{on}\:\partial \Omega \text{,}
\end{cases}

where

\Omega = B_{1}(0)

is the unit ball in

\mathbb{R}^{n}

,

ɛ > 0

is a small parameter and
f
is superlinear. It is known that this problem has multiple solutions (spikes) concentrating at some points of

\bar \Omega

. In this paper, we prove the existence of radial solutions which concentrate at
N
spheres

\bigcup _{j = 1}^{N}\{|x| = r_{j}^{ɛ}\}

, where

1 > r_{1}^{ɛ} > r_{2}^{ɛ} > ⋯ > r_{N}^{ɛ}

are such that

1−r_{1}^{ɛ} \sim ɛ\mathrm{\log }\frac{1}{ɛ}\text{,}r_{j−1}^{ɛ}−r_{j}^{ɛ} \sim ɛ\mathrm{\log }\frac{1}{ɛ}\text{,}\:j = 2\text{,}…\text{,}N

.

Résumé
On considère le problème de Neumann singulièrement perturbé suivant

\begin{cases}
ɛ^{2}\mathrm{\Delta }u−u + f(u) = 0\:&\text{dans}\:\Omega \text{;} \\
u > 0\:\text{dans}\:\Omega \:\text{et}\:\frac{\partial u}{\partial \nu } = 0\:&\text{sur}\:\partial \Omega \text{,}
\end{cases}

où

\Omega = B_{1}(0)

est la boule unité de

\mathbb{R}^{n}

,

ɛ > 0

est un paramètre petit et
f
est surlinéaire. Il est bien connu que ce problème possède plusieurs solutions se concentrant en certains points de

\bar \Omega

. Dans cet article nous prouvons l'existence de solutions radiales qui se concentrent en
N
sphères

\bigcup _{j = 1}^{N}\{|x| = r_{j}^{ɛ}\}

, où

1 > r_{1}^{ɛ} > r_{2}^{ɛ} > ⋯ > r_{N}^{ɛ}

sont tels que

1−r_{1}^{ɛ} \sim ɛ\mathrm{\log }\frac{1}{ɛ}\text{,}r_{j−1}^{ɛ}−r_{j}^{ɛ} \sim ɛ\mathrm{\log }\frac{1}{ɛ}\text{,}\:j = 2\text{,}…\text{,}N

.
Predation by herring (Clupea harengus) and sprat (Sprattus sprattus) on Cercopagis pengoi in a western Baltic Sea bay
Authors: Gorokhova Elena , Fagerberg Towe , Hansson Sture 
Published: September 2004

AbstractCercopagis pengoi is a pelagic cladoceran that has recently colonized the Baltic Sea and the Laurentian Great Lakes and is recognized as a species with the potential to affect natural foodwebs. To study the consumption of C. pengoi by zooplanktivorous fish, stomach contents of herring (size range 52–252 mm) and sprat (57–116 mm) from a coastal area of the northern Baltic proper were examined in parallel with zooplankton samples. The overall proportion of fish preying on C. pengoi was high both for sprat (70%) and for herring (61%), and it accounted for 8 ± 23% and 20 ± 33% of prey dry weight in the diets. The predation on Cercopagis depends on its abundance and on fish size; herring showed a tendency to become more selective for Cercopagis with increasing size. The majority of diapause eggs found in sprat (69%) were immature and appeared digested, while this was the case only for 2% of the eggs found in herring. These results suggest that Cercopagis has become a significant component in the diet of zooplanktivorous fish and, therefore, its abundance may be controlled by fish predation.
A question of balance: a proposal for new mouse models of autism
Authors: Murcia Crystal L. , Gulden Forrest , Herrup Karl 
Published: September 2004

AbstractAutism spectrum disorder (ASD) represents a major mental health problem with estimates of prevalence ranging from 1/500 to 1/2000. While generally recognized as developmental in origin, little to nothing is certain about its etiology. Currently, diagnosis is made on the basis of a variety of early developmental delays and/or regressions in behavior. There are no universally agreed upon changes in brain structure or cell composition. No biomarkers of any type are available to aid or confirm the clinical diagnosis. In addition, while estimates of the heritability of the condition range from 60 to 90%, as of this writing no disease gene has been unequivocally identified. The prevalence of autism is three‐ to four‐fold higher in males than in females, but the reason for this sexual dimorphism is unknown. In light of all of these ambiguities, a proposal to discuss potential animal models may seem the heart of madness. However, parsing autism into its individual genetic, behavioral, and neurobiological components has already facilitated a ‘conversation’ between the human disease and the neuropathology and biochemistry underlying the disorder. Building on these results, it should be possible to not just replicate one aspect of autism but to connect the developmental abnormalities underlying the ultimate behavioral phenotype. A reciprocal conversation such as this, wherein the human disease informs on how to make a better animal model and the animal model teaches of the biology causal to autism, would be highly beneficial.
Self‐Protection against Aminoglycoside Ototoxicity in Guinea Pigs
Authors: De Oliveira J. A. A. , Canedo D. M. , Rossato M. , De Andrade M. H. 
Published: September 2004

BACKGROUNDAmikacin is a semisynthetic aminoglycoside. It acts against most of the microbial species. Amikacin limitation of the therapeutic application is the ototoxicity which promotes permanent lesions in the cochlear system. Aminoglycoside antibiotics have ototoxic potential. The target cells are preferentially the outer hair cells in the cochlear basal turns. Amynoglicoside antibiotics can quelate iron forming a complex with oxidate properties and promotes the formation of free radicals. Responsible for production of lesions in the hair cells.OBJECTIVEThe objective of the present investigation was to determine whether the use of the aminoglycoside amikacin at small doses may lead to the occurrence of some types of resistance to or protection against ototoxicity of the drug by analyzing lesions to the organ of Corti by scanning electron microscopy.METHODSThe study was conducted on 31 guinea pigs that were divided into 4 groups, amikacin was administered intramuscularly. The groups consisted of: group A = control group: 5 animals (10 cochleae); group B = 5 animals (10 cochleae), amikacin 20 mg/kg/day for 30 days; group c = 7 animals (13 cochleae), amikacin 400 mg/kg/day for 12 days; group d = 14 animals (26 cochleae) amikacin 20 mg/kg/day for 30 days, followed by 400 mg/kg/day for 12 days. Histological studies were performed by scanning electron microscopy. Three cochleae were excluded.RESULTSIn groups A and B, the cells were normal in all cochleae, in group C there were extensive lesions of the 2 more basal turns, and in group D there was a significant reduction of lesions in the 2 more basal turns compared with group C, which had received the ototoxic dose of amikacin alone.CONCLUSIONWe conclude that the non‐ototoxic dose of amikacin administered before the ototoxic dose of the same antibiotic had a statistically significant protective effect on the 2 more basal turns of the guinea pig cochlea.
Effect of Tissue Ultrafiltration on Skin Flap Survival
Authors: Odland Rick M. , Rheuark Daryl , Ispirescu Scott , Kizziar Ron 
Published: September 2004

OBJECTIVETissue ultrafiltration (TUF) is a method of reducing tissue edema by removal of interstitial fluid. Considering the deleterious effects of edema on microcirculation and tissue viability, the effect of TUF on skin flap survival was tested.STUDY DESIGN AND SETTINGSurvival of modified McFarlane skin flaps was determined in 40 Sprague‐Dawley rats. In 20 treated animals, four 5‐cm ultrafiltration catheters were placed in the subdermal plane of the distal flap 24 hours after flap elevation and connected to a down‐regulated vacuum manifold for 8 hours. No catheters were placed in the control group.RESULTSSkin flap survival was improved in the experimental group (87.2 ± 1.6) over the control group (76.7 ± 2.2).DISCUSSIONTUF effectively improved skin flap survival. These results provide evidence of the causal effect of edema on tissue viability. The relative ease of use of TUF would allow cost‐effective clinical application of this technique.
Allergy Symptom Response to Intradermal Testing‐Based Immunotherapy: A Retrospective Study of Clinical Practice
Authors: Rouse David , Park Debra L. , Sanford Thomas 
Published: September 2004

OBJECTIVEEvaluate the multiple end‐organ targets affected by intradermal testing (IDT)‐based immunotherapy.STUDY DESIGN AND SETTINGWe conducted a retrospective medical record review of 139 patients, as well as a follow‐up questionnaire in a university setting.RESULTSStatistically significant differences (t‐tests, P < 0.05) were observed in the prevalence of symptoms after IDT‐based immunotherapy for each category (ear, eye, nasal, and throat). When divided into treatment time groups, the reduction was less in the first group (0–6 months therapy), than the subsequent groups (6–24 months and >24 months). The reduction leveled off after 6 months of therapy, with no difference seen between the 6‐ to 24‐month and >24‐month groups.CONCLUSIONSIDT‐based immunotherapy has a broad response on otolaryngic allergy symptoms that appears to be consistent over time.SIGNIFICANCEIDT‐based immunotherapy is an effective form of treatment for allergy‐induced diseases of the head and neck.
Sensitivity and Specificity of Prick and Intradermal Testing in Predicting Response to Nasal Provocation with Timothy Grass Antigen
Authors: Krouse John H. , Sadrazodi Kamran , Kerswill Kristy 
Published: September 2004

OBJECTIVEExamine the efficacy of epicutaneous and intradermal testing in predicting response to nasal provocation with timothy antigen.STUDY DESIGN AND SETTINGProspective study. Subjects were tested with Multi‐Test II (MT). Subjects with negative wheals were tested with a 1:500 intradermal injection of timothy. They had baseline assessment of nasal cross‐sectional area (CSA) using acoustic rhinometry and underwent nasal provocation with increasing timothy concentrations. CSA was assessed and nasal visual analog scale (VAS) completed with each concentration.RESULTSSensitivity and specificity of MT in predicting nasal response to provocation were 87% and 86%. Intradermal testing increased sensitivity to 93%. Hierarchical linear modeling (HLM) demonstrated that subjects positive to skin testing had significant reductions in CSA and worsening VAS scores with increasing concentrations of nasally delivered antigen.CONCLUSION AND SIGNIFICANCEEpicutaneous testing with the Multi‐Test II offers 87% sensitivity and 86% specificity in assessing timothy grass reactivity.