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PubMed2000

Comparison of various liquid chromatographic methods involving UV and atmospheric pressure chemical ionization mass spectrometric detection for the efficient trace analysis of phenylurea herbicides in various types of water samples.

The performance of mass spectrometric (MS) detection and UV detection in combination with reversed-phase liquid chromatography without and with the use of coupled column RPLC (LC-LC) has been compared for the trace analysis of phenylurea herbicides in environmental waters. The selected samples of this comparative study originated from an inter-laboratory study. For both detection modes, a 50 mm x 4.6 mm I.D. column and a 100 mm x 4.6 mm I.D. column packed with 3 microm C18 were used as the first (C-1) and second (C-2) column, respectively. Atmospheric pressure chemical ionization mass spectrometry was performed on a magnetic sector instrument. The LC-LC-MS analysis was carried out on-line by means of direct large volume (11.7 ml) injection (LVI). The performance of both on-line (LVI, 4 ml of sample) and off-line LC-LC-UV (244 nm) analysis was investigated. The latter procedure consisted of a solid-phase extraction (SPE) of 250 ml of water sample on a 500 mg C18 cartridge. The comparative study showed that LC-LC-MS is more selective then LC-LC-UV and, in most cases, more sensitive. The LVI-LC-LC-MS approach combines direct quantification and confirmation of most of the analytes down to a level of 0.01 microg/l in water samples in less then 30 min. As regards LC-LC-UV, the off-line method appeared to be a more viable approach in comparison with the on-line procedure. This method allows the screening of phenylurea's in various types of water samples down to a level of at least 0.05 microg/l. On-line analysis with LVI provided marginal sensitivity (limits of detection of about 0.1 microg/l) and selectivity was sometimes less in case of surface water samples. Both the on-line LVI-LC-LC-MS method and the LC-LC-UV method using off-line SPE were validated by analysing a series of real-life reference samples. These samples were part of an inter-laboratory test and contained residues of herbicides ranging from 0.02 to 0.8 microg/l. Beside good correlation between the methods the data agreed very well with the true values of the samples.

Atmospheric Pressure↗

PubMed2003

Effect of fulvic acid on the sorption of Cu and Pb onto gamma-Al2O3.

This work investigated the adsorption of Cu and Pb at the surface of gamma-Al(2)O(3) in the presence of fulvic acid to address the significance of dissolved organic matters on metal partitioning. Fulvic acid, obtained from International Humic Substance Society, represented dissolved organic matter. Fulvic acid concentrations employed herein were 1, 5, and 10 mg C/L, which simulated the relevant environmental conditions. Ion selective electrodes were employed to ascertain free Cu and Pb measurements. The maximum adsorption of 10mg C/L fulvic acid on gamma-Al(2)O(3) was 5 x 10(-2)mgC/mg gamma-Al(2)O(3). Fulvic acid promoted Cu adsorption in low pH conditions. The effects of fulvic acid on Pb adsorption were similar to those of Cu. The conditional stability constants of sorbed fulvic acids with Cu and Pb were determined to be in the order of 4 to 6 (log K). Cu and Pb species were modeled in heterogeneous systems using triple-layer model. Simulation results indicated that metal species are dominantly in complexation with fulvic acid, both in solution and at the gamma-Al(2)O(3) surface.

Adsorption↗

PubMed2000

Measurement of trihalomethanes in potable and recreational waters using solid phase micro extraction with gas chromatography-mass spectrometry.

Solid phase micro extraction (SPME) was applied to the determination of selected trihalomethanes (THMs), chloroform, bromodichloromethane, dibromochloromethane, bromoform, in potable and recreational waters. The selected samples were environmentally significant due to mandatory limits imposed by regulatory agencies. Extraction of the analytes was performed using headspace SPME (fused silica fibre with a 100 microm poly(dimethylsiloxane coating) followed by thermal desorption at 220 degrees C and GC-MS analysis. A linear working range of 10-160 microg/l was established with relative standard deviations (%RSD) within the range, 0.9-19%. Limits of detection (LOD) were 1.0-2.8 microg/l. The highest THM concentration was 61.8 microg/l which was well within the proposed European Union directive of 100 microg/l. The total THMs determined in swimming pool waters ranged from 105-134 microg/l, with chloroform accounting for 84-86% of total THM.

Bromine↗

PubMed1997

Factors associated with superior antibody responses to a single dose of Haemophilus influenzae type b-tetanus toxoid conjugate vaccine administered to Chilean infants at 2 months of age.

The anticapsular antibody response of Chilean infants to a single dose of Haemophilus influenzae type b capsular polysaccharide-tetanus toxoid conjugate, vaccine is substantially higher than that observed among infants of similar age from the USA. Comparison of selected demographic and environmental factors indicates that low maternal education and a greater number of persons in the home are significantly associated with the superior responder phenotype. High anticapsular antibody responses were associated with high antibody responses to tetanus toxoid, the carrier protein in this conjugate, but not to diphtheria toxoid. These data suggest that environmental factors may enhance the magnitude of the primary antibody response to PRP-T vaccine.

Antibodies, Bacterial↗

PubMed2000

Culture and courtship in vertebrates: a review of social learning and transmission of courtship systems and mating patterns.

Female and male animals often choose mates based upon the complementarity of their courtship behaviours and preferences. The importance of this fact on the evolutionary dynamics of populations has long been appreciated. What has not been appreciated is the role that social learning might play in the transmission of systems of courtship behaviour across generations. This paper addresses the social transmission of courtship behavioural traditions in vertebrates. It discusses views of culture in the context of behavioural signals and preferences in courtship. It then reviews empirical evidence for culture-like processes affecting courtship behaviour, focusing on studies of song learning in passerine birds and work on social learning of mating preferences. The paper concludes with potential future directions for research on social traditions in systems of courtship behaviour, including determining mechanisms of transmission, genetic and non-social environmental effects, and selective factors influencing the stability of behavioural traditions over time. By integrating proximate and ultimate questions for the transmission of courtship systems, this work would increase our understanding of the ways individual development, cultural processes, and population evolution influence, and are in turn influenced by, one another.

Journal Article↗

PubMedDate not supplied

Semen analysis of military personnel associated with military duty assignments.

A collaborative study between the U.S. Army Biomedical Research and Development Laboratory (USABRDL) and the National Institute for Occupational Safety and Health (NIOSH) was designed to assess fecundity of male artillery soldiers with potential exposures to airborne lead aerosols. Potential exposure assessment was based upon information provided in an interactive questionnaire. It became apparent from extensive questionnaire data that many soldiers in the initial control population had potentially experienced microwave exposure as radar equipment operators. As a result, a third group of soldiers without potential for lead or microwave exposures, but with similar environmental conditions, was selected as a comparison population. Blood hormone levels and semen analyses were conducted on artillerymen (n = 30), radar equipment operators (n = 20), and the comparison group (n = 31). Analysis of the questionnaire information revealed that concern about fertility problems motivated participation of some soldiers with potential artillery or microwave exposures. Although small study population size and the confounding variable of perceived infertility limit the reliability of the study, several statistically significant findings were identified. Artillerymen who perceived a possible fertility concern demonstrated lower sperm counts/ejaculate (P = 0.067) and lower sperm/mL (P = 0.014) than the comparison group. The group of men with potential microwave exposures demonstrated lower sperm counts/mL (P = 0.009) and sperm/ejaculate (P = 0.027) than the comparison group. Variables used to assess endocrine, accessory sex gland, and sperm cell function were not different than the comparison group. Additional studies, incorporating larger numbers of individuals, should be performed in order to more optimally characterize potential lead and microwave exposure effects on male fecundity.

Adult↗

PubMedDate not supplied

Functional multimodality of axonal tree in invertebrate neurons.

This review, based on invertebrate neuron examples, aims at highlighting the functional consequences of axonal tree organization. The axonal organization of invertebrate neurons is very complex both morphologically and physiologically. The first part shows how the transfer of information along sensory axons is modified by presynaptic inhibition mechanisms. In primary afferents, presynaptic inhibition is involved in: 1) increasing the dynamic range of the sensory response; 2) processing the sensory information such as increasing spatial and/or temporal selectivity; 3) discriminating environmental information from sensory activities generated by the animal's own movement; and 4) modulating the gain of negative feedback (resistance reflex) during active rhythmic movements such as locomotion. In a second part, the whole organization of other types of neurons is considered, and evidence is given that a neuron may not work as a unit, but rather as a mosaic of disconnected 'integrate-and-fire' units. Examples of invertebrate neurons are presented in which several spike initiating zones exist, such as in some stomatogastric neurons. The separation of a neuron into two functionally distinct entities may be almost total with distinct arborizations existing in different ganglia. However, this functional separation is not definitive and depends on the state of the neuron. In conclusion, the classical integrate-and-fire representation of the neuron, with its dendritic arborization, its spike initiating zone, its axon and axonal tree seems to be no more applicable to invertebrate neurons. A better knowledge of the function of vertebrate neurons would probably demonstrate that it is the case for a large number of them, as suggested by the complex architecture of some reticular interneurons in vertebrates.

Animals↗

PubMed2002

The energetics of barnacle geese (Branta leucopsis) flying in captive and wild conditions.

Experimental data on the relationship between mean heart rate (f(H)) and mean rate of oxygen consumption (VO(2)) of captive barnacle geese during flights in a wind tunnel are assessed in terms of their capacity to predict the typical VO(2) of wild barnacle geese, based on the recordings of their f(H), while undertaking autumn migratory flights between Spitsbergen (78 degrees N) and Caerlaverock, Scotland (55 degrees N). A significant linear relationship has been demonstrated between the f(H) and simultaneously recorded VO(2) of a single barnacle goose (B-B) flying in the wind tunnel (VO(2)=1.42 f(H)-304, r(2)=0.82, P<0.001, N=12 flights). Data recorded from three additional geese (N=4 flights), lay within the 95% prediction intervals of the relationship for goose B-B. When these geese (mean body mass=2.06 kg, n=4) were flown in the wind tunnel (WT) without the mask, they had a mean f(H) of 451+/-23 beats min(-1), yielding an estimate for VO(2) of 336+/-33 ml min(-1). However, f(H) has also been recorded from wild barnacle geese (mean migratory f(H) of 253 beats min(-1)), and substitution of this value into the above calibration equation results in an unrealistically low value for mean migratory VO(2) of only 55 ml min(-1). Various factors, such as differences in heart mass, selective tissue perfusion, environmental temperature and flock formation, which might account for some of the difference in f(H) between the captive and wild geese are discussed. Comparison with other WT studies shows that inter-species minimum mass-specific VO(2) declines with increasing body mass (M(b); range 0.035-2.8 kg) as 173 M(b)(-0.224), r(2)=0.848.

Animals↗

PubMed2006

Multifunctional chemical vapor sensors of aligned carbon nanotube and polymer composites.

Partially coating perpendicularly aligned carbon nanotube arrays with an appropriate polymer thin film along their tube length provides a novel concept for developing new sensors of high sensitivity, good selectivity, and excellent environmental stability for the detection of a broad class of chemical vapors with low power consumption. The absorption and desorption of chemical vapors by the polymer matrix cause changes in the inter-tube distance and, hence, the surface resistance across the nanotube film. Simple measurements of the resistance change, therefore, constitute the nanotube-polymer chemical vapor sensors. These rationally designed, aligned carbon nanotube-polymer composite films are flexible and can be effectively integrated into many systems for a wide range of potential applications, including their use as multifunctional sensors for sensing chemical vapors, mechanical deformations, thermal and optical exposures.

Journal Article↗

PubMed2006

Tissue distribution, elimination, and metabolism of sodium [36Cl]perchlorate in lactating goats.

Perchlorate has contaminated water sources throughout the United States but particularly in the arid Southwest, an area containing large numbers of people and few water sources. Recent studies have demonstrated that perchlorate is present in alfalfa and that perchlorate is secreted into the milk of cows. Studies in lactating cows have indicated that only a small portion of a perchlorate dose could be accounted for by elimination in milk, feces, or urine. It was hypothesized that the remainder of the perchlorate dose was excreted as chloride ion. The purpose of this study was to determine the fate and disposition of (36)Cl-perchlorate in lactating dairy goats. Two goats (60 kg) were each orally administered 3.5 mg (16.5 muCi) of (36)Cl-perchlorate, a dose selected to approximate environmental perchlorate exposure but that would allow for adequate detection of radioactive residues after a 72 h withdrawal period. Blood, milk, urine, and feces were collected incrementally until slaughter at 72 h. Total radioactive residue (TRR) and perchlorate concentrations were measured using radiochemical techniques and liquid chromatography mass spectrometry (LC-MS-MS). Peak blood levels of TRR occurred at 12 h ( approximately 195 ppb) postdose; peak levels of parent perchlorate, however, occurred after only 2 h, suggesting that perchlorate metabolism occurred rapidly in the rumen. The serum half-life of perchlorate was estimated to be 2.3 h. After 24 h, perchlorate was not detectable in blood serum but TRR remained elevated (160 ppb) through 72 h. Milk perchlorate levels peaked at 12 h (155 ppb) and were no longer detectable by 36 h, even though TRRs were readily detected through 72 h. Perchlorate was not detectable in skeletal muscle or liver at slaughter (72 h). Chlorite and chlorate were not detected in any matrix. The only radioactive residues observed were perchlorate and chloride ion. Bioavailability of perchlorate was poor in lactating goats, but the perchlorate that was absorbed intact was rapidly eliminated in milk and urine.

Animals↗

PubMed1999

Genetic and phenotypic diversity of Saccharomyces sensu stricto strains isolated from Amarone wine. Diversity of Saccharomyces strains from Amarone wine.

Individual yeast strains belonging to the Saccharomyces sensu stricto complex were isolated from Amarone wine produced in four cellars of the Valpolicella area (Italy) and characterized by conventional physiological tests and by RAPD-PCR and mtDNA restriction assays. Thirteen out of 20 strains were classified as Saccharomyces cerevisiae (ex S. cerevisiae p.r. cerevisiae and p.r. bayanus) and the remaining as Saccharomyces bayanus (ex S. cerevisiae p.r. uvarum). RAPD-PCR method proved to be a fast and reliable tool for identification of Saccharomyces sensu stricto strains and also gave intraspecific differentiation. Restriction analysis of mtDNA permitted to distinguish S. cerevisiae and S. bayanus species and to discern polymorphism among S. cerevisiae isolates. The assessment of the phenotypic diversity within the isolates by gas-chromatographic analysis of secondary fermentation products was explored. Small quantities of isobutanol were produced by most of the strains and higher amounts by some S. cerevisiae strains with phenotypes Gal- and Mel-; all S. bayanus strains produced low amounts of amilyc alcohols. From this study it appears that each winery owns particular strains, with different genetic and biochemical characteristics, selected by specific environmental pressures during the Amarone winemaking process carried out at low temperature in presence of high sugar content.

Cluster Analysis↗

PubMed2003

An international survey of indoor air quality, ventilation, and smoking activity in restaurants: a pilot study.

During a pilot study of indoor air quality in restaurants, a survey was performed in 34 medium-priced restaurants in six countries in Asia, Europe, and North America using a uniform protocol. The concentration of selected constituents of environmental tobacco smoke (ETS) present in occupied areas was determined during lunch and dinner periods by measuring the levels of four particulate-phase markers and two gas-phase markers. The particulate-phase markers determined were respirable suspended particles, ultraviolet particulate matter, fluorescing particulate matter, and solanesol particulate matter. The gas-phase markers were nicotine and 3-ethenylpyridine (3-EP). Correlation between the markers was investigated to explore an improved monitoring approach. It was concluded that at least one marker in each phase was necessary to describe adequately the ETS load. An assessment was made of the ventilation system in each restaurant, and effective ventilation rates were determined based on CO(2) measurements. Smoking activity was also monitored. These data were used to model nicotine and 3-EP concentrations that resulted in a satisfactory prediction of their levels, especially at the higher concentrations. A total number of 1370 questionnaires were returned by the restaurant patrons in five countries. In some countries, dissatisfaction rates above 20% were observed for draft, freshness of air, and noise. The dissatisfaction rates related to tobacco smoke were less than 20%, which is lower than would be predicted based on measured ETS levels. Based on the results of this international pilot study, recommendations are given for future studies of this type.

Air Pollution, Indoor↗

PubMed2003

Emergence and evolution of Vibrio cholerae O139.

The emergence of Vibrio cholerae O139 Bengal during 1992-1993 was associated with large epidemics of cholera in India and Bangladesh and, initially, with a total displacement of the existing V. cholerae O1 strains. However, the O1 strains reemerged in 1994 and initiated a series of disappearance and reemergence of either of the two serogroups that was associated with temporal genetic and phenotypic changes sustained by the strains. Since the initial emergence of the O139 vibrios, new variants of the pathogen derived from multiple progenitors have been isolated and characterized. The clinical and epidemiological characteristics of these strains have been studied. Rapid genetic reassortment in O139 strains appears to be a response to the changing epidemiology of V. cholerae O1 and also a strategy for persistence in competition with strains of the O1 serogroup. The emergence of V. cholerae O139 has provided a unique opportunity to witness genetic changes in V. cholerae that may be associated with displacement of an existing serogroup by a newly emerging one and, thus, provide new insights into the epidemiology of cholera. The genetic changes and natural selection involving both environmental and host factors are likely to influence profoundly the genetics, epidemiology, and evolution of toxigenic V. cholerae, not only in the Ganges Delta region of India and Bangladesh, but also in other areas of endemic and epidemic cholera.

Bangladesh↗

PubMed2006

Urban aerosols harbor diverse and dynamic bacterial populations.

Considering the importance of its potential implications for human health, agricultural productivity, and ecosystem stability, surprisingly little is known regarding the composition or dynamics of the atmosphere's microbial inhabitants. Using a custom high-density DNA microarray, we detected and monitored bacterial populations in two U.S. cities over 17 weeks. These urban aerosols contained at least 1,800 diverse bacterial types, a richness approaching that of some soil bacterial communities. We also reveal the consistent presence of bacterial families with pathogenic members including environmental relatives of select agents of bioterrorism significance. Finally, using multivariate regression techniques, we demonstrate that temporal and meteorological influences can be stronger factors than location in shaping the biological composition of the air we breathe.

Aerosols↗

PubMed2001

Effects of exposure to event 176 Bacillus thuringiensis corn pollen on monarch and black swallowtail caterpillars under field conditions.

The widespread planting of corn genetically modified to produce Bacillus thuringiensis endotoxin has led to speculation that pollen from these fields might adversely affect nearby nontarget lepidopterans. A previous study of Bt corn engineered with Monsanto event 810 failed to detect an effect of pollen exposure on the black swallowtail, Papilio polyxenes, in either the field or the laboratory. Here, we report results of a field study investigating the impact of exposure to pollen from a Bt corn hybrid containing Novartis event 176 on two species of Lepidoptera, black swallowtails and monarch butterflies, Danaus plexippus. Nearly half of the 600 monarch larvae died within the first 24 h; this and subsequent mortality was not associated with proximity to Bt corn and may have been due in part to predation. Survivorship of black swallowtails was much higher than that of the monarchs and was also independent of proximity to the transgenic corn. However, despite five rainfall events that removed much of the pollen from the leaves of their host plants during the experiment, we observed a significant reduction in growth rates of black swallowtail larvae that was likely caused by pollen exposure. These results suggest that Bt corn incorporating event 176 can have adverse sublethal effects on black swallowtails in the field and underscore the importance of event selection in reducing environmental impacts of transgenic plants.

Animals↗

PubMed2001

Environmental factors associated with rodent infestations in Argentine poultry farms.

1. Seasonal variations in rodent infestations were studied at poultry farms in central Argentina as well as the environmental factors associated with rodent infestations at poultry farms. 2. During the summer and winter of 1998 rodent infestation was monitored at 10 poultry farms by means of tracking stations, and 21 environmental variables were selected that a priori could be related with the extent of rodent infestation. 3. There was a higher rodent infestation in winter than in summer. 4. Species detected by rodent sightings at the poultry farms included Akodon azarae, Calomys spp. (C. laucha and possibly C. musculinus) and Mus musculus. 5. In summer, rodent infestation was positively associated with the perimeter of the farm, whereas there was an inverse relationship with the maintenance conditions of the sheds. In winter, rodent infestation was positively associated with the percentage of the borders of the farm covered with vegetation, and with the amount of plant cover, especially the amount of plant cover which was above 20 cm in height. 6. There was no significant relationship between rodent infestation and the time lag since the last application of rodenticide (first-generation anticoagulant) at the farms. 7. These results suggest that strategies for controlling rodents based solely on chemical methods may not be good enough for efficient rodent control. Farms which are properly managed, with a better control of vegetation growth at both the perimeter and within the internal area, in addition to a higher maintenance of sheds have appreciably lower rodent infestations.

Animal Husbandry↗

PubMed2005

Antecedent interventions in the management of maladaptive behaviours in a child with brain injury.

Typically behaviour management plans attempt to change behaviour by manipulating the environmental consequences of selected behaviour. However, identifying the antecedent events that precede behaviour has also been demonstrated to be an important component of effective behaviour change programmes. The present case presentation attempts to demonstrate how antecedent procedures could be used to effectively manage behaviour problems in individuals with brain injury. Visual inspection of changes in the frequency of physical aggression and self-injurious behaviour of a child with brain injury provides preliminary data supporting the use of an intervention package of antecedent and consequence-based procedures. Clinical implications, limitations and possibilities for future research of antecedent control procedures are discussed.

Aggression↗

PubMed1998

Indoor emissions from conversion varnishes.

Conversion varnishes are two-component, acid-catalyzed varnishes that are commonly used to finish cabinets. They are valued for their water and stain resistance, as well as their appearance. They have been found, however, to contribute to indoor emissions of organic compounds. For this project, three commercially available conversion varnish systems were selected. A U.S. Environmental Protection Agency (EPA) Method 24 analysis was performed to determine total volatile content, and a sodium sulfite titration method was used to determine uncombined (free) formaldehyde content of the varnish components. The resin component was also analyzed by gas chromatography/mass spectroscopy (GC/MS) (EPA Method 311 with an MS detector) to identify individual organic compounds. Dynamic small chamber tests were then performed to identify and quantify emissions following application to coupons of typical kitchen cabinet wood substrates, during both curing and aging. Because conversion varnishes cure by chemical reaction, the compounds emitted during curing and aging are not necessarily the same as those in the formulation. Results of small chamber tests showed that the amount of formaldehyde emitted from these coatings was 2.3-8.1 times the amount of free formaldehyde applied in the coatings. A long-term test showed a formaldehyde emission rate of 0.17 mg/m2/hr after 115 days.

Air Pollutants, Occupational↗