Temporal dynamics of gut microbiota in triclocarban-exposed weaned rats

Environmental Science and Pollution Research - Widely used as an antimicrobial in antibacterial bar soaps, triclocarban (3,4,4′-trichlorocarbanilide; TCC) is effective against Gram-positive...     

The effect of atmospheric thermal conditions and urban thermal pollution on all-cause and cardiovascular mortality in Bangladesh

This study assessed the effect of temperature and thermal atmospheric conditions on all-cause and cardiovascular mortality in Bangladesh. In particular, differences in the response to elevated temperatures between urban and rural areas were investigated. Generalized additive models (GAMs) for daily death counts, adjusted for trend, season, day of the month and age were separately fitted for urban and rural areas. Breakpoint models were applied for determining the increase in mortality above and below a threshold (equivalent) temperature. Generally, a 'V'-shaped (equivalent) temperature-mortality curve with increasing mortality at low and high temperatures was observed. Particularly, urban areas suffered from heat-related mortality with a steep increase above a specific threshold. This adverse heat effect may well increase with ongoing urbanization and the intensification of the urban heat island due to the densification of building structures. Moreover, rising temperatures due to climate change could aggravate thermal stress.     

Verantwortungsvoller Umgang mit der Ressource Boden – Workshop zur Erarbeitung eines Aachener Modells für ein nachhaltiges Landmanagement am Niederrhein

Ohne Zusammenfassung     

Dynamic simulation of a decentralized polygeneration plant providing SNG,steam and power

The behaviour of a decentralized polygeneration plant providing synthetic natural gas (SNG), steam and electrical power is simulated in three scenarios in this study. The plant size is based on an assumed capacity of decentralized polygeneration plants processing 1070 m³ h^?1 (STP) of syngas. 396 m³ h^?1 (STP) of raw SNG, 0.4 t h^?1 of steam at 5 bar and 670 kW of electrical power can be generated by the plant at the reference scenario. Methanation reactor and steam generator are modelled in detail. Further results indicate that such a polygeneration plant can provide positive and negative operation reserves for the electricity network to the extent of 100% of the reference power output, while the amount of generated steam varies by less than 40%. At the same time, the generated SNG quality keeps constant. Lower variations in the amount of generated steam are applicable when reducing the operation reserve capacity.     

The modulation of worker behavior by the vibration signal during house hunting in swarms of the honeybee, Apis mellifera

During house hunting, honeybee, Apis melli- fera, workers perform the vibration signal, which may function in a modulatory manner to influence several aspects of nestsite selection and colony movement. We examined the role of the vibration signal in the house-hunting process of seven honeybee swarms. The signal was performed by a small proportion of the older bees, and 20% of the vibrating bees also performed waggle dances for nestsites. Compared to non-vibrating controls, vibrating bees exhibited increased rates of locomotion, were more likely to move into the interiors of the swarms, and were more likely to fly from the clusters and perform waggle dances. Recipients responded to the signal with increased locomotion and were more likely than non- vibrated controls to fly from the swarms. Because vibration signals were intermixed with waggle dances by some vibrators, and because they stimulated flight in recipients, the signals may have enhanced nestsite scouting and recruitment early in the house-hunting process. All swarms exhibited increased vibration activity within 0.5–1 h of departure. During these final periods, numerous vibrating bees wove repeatedly in and out of the clusters while signaling and motion on the swarms increased until it culminated in mass flight. The peaks of vibration activity observed at the end of the house-hunting process may therefore have activated the entire swarm for liftoff once a new nestsite had been selected. Thus, the vibration signal may help to integrate the behavior of numerous groups of workers during nestsite selection and colony relocation. Received: 17 January 2000 / Received in revised form: 5 April 2000 / Accepted: 3 May 2000     

Evaluation of fumigation and surface seal methods on fumigant emissions in an orchard replant field

Soil fumigation is an important management practice for controlling soil pests and enabling successful replanting of orchards. Reducing emissions is required to minimize the possible worker and bystander risk and the contribution of fumigants to the atmosphere as volatile organic compounds that lead to the formation of ground-level ozone. A field trial was conducted in a peach orchard replant field to investigate the effects of fumigation method (shank-injection vs. subsurface drip-application treatments) and surface treatments (water applications and plastic tarps) on emissions of 1,3-dichloropropene (1,3-D) and chloropicrin (CP) from shank-injection of Telone C-35 and drip application of InLine. Treatments included control (no water or soil surface treatment); standard high-density polyethylene (HDPE) tarp, virtually impermeable film (VIF) tarp, and pre-irrigation, all over shank injection; and HDPE tarp over and irrigation with micro-sprinklers before and after the drip application. The highest 1,3-D and CP emission losses over a 2-wk monitoring period were from the control (36% 1,3-D and 30% CP) and HDPE tarp (43% 1,3-D and 17% CP) over shank injection. The pre-irrigation 4 d before fumigation and VIF tarp over shank injection had similar total emission losses (19% 1,3-D and 8-9% CP). The HDPE tarp and irrigations over subsurface drip-application treatments resulted in similar and the lowest emission losses (12-13% 1,3-D, and 2-3% CP). Lower fumigant concentrations in the soil-gas phase were observed with drip-application than in the shank-injection treatments; however, all treatments provided 100% kill to citrus nematodes in bags buried from 30 to 90 cm depth. Pre-irrigation and drip application seem to be effective to minimize emissions of 1,3-D and CP.     

Toxicity testing with luminescent bacteria – Characterization of an automated method for the combined assessment of acute and chronic effects

The luminescent bacteria test according to EN ISO 11348 is frequently applied in (eco) toxicity testing and is applicable for a huge variety of environmental and industrial samples. A big disadvantage of this method is the very short exposure time, which is expressed in a low sensitivity in regard to substances with a delayed effect. Chronic effects, i.e. interference with cell growth, cannot be assessed with this conventional standard method. The goal of this research was to develop an automated testing system for long term toxicity towards the luminescent bacteria Vibrio fischeri by implementing microtitration-based instrumentation. The optimized method, hereinafter referred to as “kinetic luminescent bacteria test”, can be described as a miniaturized combination of the conventional short-term luminescence inhibition test according to EN ISO 11348 and the Photobacterium phosphoreum growth inhibition test (DIN 38412-37). The validation procedure included the evaluation of six reference compounds (3,4-Dichloroaniline, 3,5-Dichlorophenol, Chloramphenicol, Streptomycin sulfate, Potassium dichromate, Zinc sulfate heptahydrate) and three different endpoints that are acute luminescence inhibition (acute LI) after 30 min, chronic luminescence inhibition (chronic LI) after 24 h and growth inhibition (GI) after 14 h. The optimized method allows the assessment of acute and chronic effects within one test, by what a misinterpretation of the toxicity of substances with delayed bacterial toxicity can be prevented, without abandoning most of the advantages of the conventional short-term test. Therefore, the kinetic luminescent bacteria test is exceptional as an initial screening test for environmental samples or substances with unknown (eco) toxicological characteristics.     

Zooplankton standing stock and community size structure within the epipelagic zone: a comparison between the central Red Sea and the Gulf of Aden

Standing stock and size composition of the zooplankton comunity (>100 m) were studied in four depth strata of the upper 200 m of the water column during a Meteor cruise to the central Red Sea and Gulf of Aden in spring 1987. The central Red Sea was divided into a northern area of higher salinity and a less saline southern part. Both areas exhibited significant differences in zooplankton abundance and standing stock. The latter increased by the ratio 1:2:3 from the northern central Red Sea to its southern part and further south to the Gulf of Aden. For size structure analysis samples were fractionated into three size classes (100 to 300, 300 to 500, 500 to 5000 m). In the central Red Sea the smallest size was dominant whereas in the Gulf of Aden the largest size fraction played a greater relative role than in the central Red Sea. This shift in size structure of the zooplankton community from the Red Sea to the Gulf of Aden is apparently primarily related to ecosystem difference between both areas, leading to a change in species composition. In addition, size reduction of individual species common to both seas may be of some significance in the extreme environment of the Red Sea.     

Development of an enzyme-linked immunosorbent assay for atrazine monitoring in water samples

The implementation of the Water Framework Directive (2000/60/EC) requires the establishment of monitoring programs. However, conventional procedures for sample preparation prior to chromatographic analysis are rather expensive and time consuming, being the development of cost-effective and easy tool a necessity. The aim of this work was to develop an enzyme-linked immunosorbent assay (ELISA) able to determine atrazine in water samples. Matrix effects evaluation showed that the increase of humic acid (HA) concentration leads to flattened calibration curves and to the loss of the sigmoidal shape. However, such interference was overcome, by the presence of an environmental sample buffer, incubated together with the samples. Recoveries from 88.5 to 119.2 % were obtained in the presence of HA concentrations up to 20 mg?L^?1. An analytical range from 0.003 to 1 μg?L^?1 was obtained, and atrazine was detected in a sewage treatment plant with concentrations ranging from 14 to 52 ng?L^?1.