Modular development of an inline monitoring system for waterborne pathogens in raw and drinking water     

Daniel Karthe  Ole Behrmann  Verena Blättel  Dennis Elsässer  Christian Heese  Matthias Hügle  Frank Hufert  Andreas Kunze  Reinhard Niessner  Johannes Ho  Buren Scharaw  Matthias Spoo  Andreas Tiehm  Gerald Urban  Silvia Vosseler  Thomas Westerhoff  Gregory Dame  Michael Seidel 《Environmental Earth Sciences》2016,75(23):1481

The state-of-the-art monitoring of drinking water hygiene is based on the cultivation and enumeration of indicator bacteria. Despite its proven reliability, this approach has the disadvantages of being (a) relatively slow and (b) limited to a small number of indicator bacteria. Ideally, alternative methods would be less time-consuming while providing information about a larger set of hygienically relevant microorganisms including viruses. In this paper, we present insights into the design of a modular concentration and detection system for bacteria, bacteriophages and viruses. Following further validation, this or similar techniques have the potential to extend and speed up the monitoring of raw and drinking water hygiene in the future. The system consists of different modules for the concentration of microorganisms, an amplification and detection unit that includes a module for the differentiation between live and dead microorganisms, and an automated system for decision support and self-diagnosis. The ongoing testing under controlled laboratory conditions and real-life conditions in the water supply industry yields further system improvements. Moreover, the increased sensitivity and broader range of microbiological parameters emphasize the need for a reconsideration of the currently used criteria for the assessment of (drinking) water hygiene.  相似文献   

Locational Shifts In Supermarket Patronage     

J. Dennis Lord 《The Professional geographer》1975,27(3):310-314

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The excitation of the iron Kα feature in solar flares     

A. Gordon Emslie  Kenneth J. H. Phillips  Brian R. Dennis 《Solar physics》1986,103(1):89-102

We evaluate the relationship between the hard X-ray photon spectrum and the flux of iron K emission in a thick-target electron bombardment model. Results are presented for various power-law hard X-ray spectra. We then apply these results to two events observed with the Hard X-Ray Burst Spectrometer and the K channel of the X-Ray Polychromator Bent Crystal Spectrometer on the Solar Maximum Mission satellite. For one of the events, on 29 March, 1980, at 09:18 UT, the K flux predicted for a thick-target non-thermal process is significant compared to the background fluorescent component, and the data are indeed consistent with an enhancement of the predicted amount. For the other event, on 14 October, 1980 at 06:09 UT, the hard X-ray spectrum is so steep that no significant Ka flux is predicted for this process, and no enhancement is seen. We conclude that the agreement between the predicted K flux and the observed magnitude of the K enhancement above the fluorescent background at the time of the large hard X-ray bursts lends support to a thick-target non-thermal interpretation of impulsive hard X-ray emission in solar flares.  相似文献   

QUALIFYING RELIEF TERMS     

Robert R. Drummond  Howard W. Dennis 《The Professional geographer》1968,20(5):326-332

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The Eocene succession at afton brickyard I.O.W.     

Dennis Curry 《Proceedings of the Geologists' Association. Geologists' Association》1942,53(2):88-IN3

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Effects of toxic dinoflagellate Alexandrium tamarense on the energy budgets and growth of two marine bivalves   总被引：1，自引：0，他引：1  

Li SC  Wang WX  Hsieh DP 《Marine environmental research》2002,53(2):145-160

Harmful algal blooms (HAB) may impose a serious threat to aquatic lives and human health. We determined the effects of a toxic dinoflagellate Alexandrium tamarense (clone ATCIO1, isolated from Hong Kong coastal waters) on the energy budget, quantified as scope for growth (SFG), and the growth rate of the manila clam Ruditapes philippinarum and the green-lipped mussel Perna viridis. To quantify the SFG, clams and mussels were dosed with different amounts of toxic A. tamarense for 6 days, resulting in different toxin burdens in the tissues. Clearance rate, absorption efficiency, and respiration rate were subsequently measured in these toxin containing bivalves. Clearance rate significantly declined at the highest toxin burden in the clams only, while there was no significant difference in the clearance rate among different treatments for the mussels. The respiration rate of either bivalve was not significantly affected by toxin accumulation in the tissues. In contrast, the absorption efficiency of both clams and mussels decreased, in a concentration-dependent manner for mussels but not for clams, when the tissue accumulated the toxins. With an increase in paralytic shellfish poisoning (PSP) toxin burden, SFG in both clams and mussels was significantly reduced, primarily because of the decrease of absorption efficiency. The growth rate of juvenile clam R. philippinarum, measured as an increment in tissue dry weight over a 15 d exposure period, was significantly lower during their feeding on toxic dinoflagellate than the growth rate of clams feeding on the diatom Thalassiosira pseudonana. The juvenile mussel P. viridis, however, exhibited similar growth rates after feeding on the toxic dinoflagellates and the nontoxic diatom. This study showed that SFG can provide a sensitive and integrated measure of the effect of HAB on the physiology of bivalves. Clam R. philippinarum may be more sensitive, in terms of their energy budget, to PSP toxin accumulation than the mussel P. viridis.  相似文献   

The role of cytochrome P-450 in the metabolism of pollutants     

Dennis V. Parke 《Marine environmental research》1985,17(2-4)

The monooxygenase cytochrome P-450 is a ubiquitous enzyme well known for its role in the detoxication of drugs and xenobiotics and the biosynthesis of the steroid hormones. The toxicity and carcinogenicity of many chemicals is frequently due to the formation of oxygenated reactive intermediates, which are formed by the same enzymes that effect the detoxication of these chemicals, namely the cytochromes P-450. In mammalia the cytochromes P-450 exist as a group of isoenzymes with overlapping substrate affinities, selectively and differentially induced by their specific substrates or inhibitors. As few enzyme assays have been shown to be specific for a particular cytochrome P-450 isoenzyme the characterisation of these isoenzymes has been dependent on their isolation and purification. It is therefore important to know whether one or more isoenzyme of cytochrome P-450 is specifically concerned with the activation of carcinogens and chemicals, rather than their detoxication, and to develop a specific enzymic assay for this activating enzyme.  相似文献   

A comparison of ozone and chlorine toxicity to three life stages of the American oyster Crassostrea virginica     

Leonard B Richardson  Dennis T Burton  Ann M Stavola 《Marine environmental research》1982,6(2):99-113

The effects of ozone-produced oxidants (OPO) on three developmental stages of the American oyster, Crassostrea virginica, were evaluated. Both straight-hinge (48-h post fertilisation) and setting pediveliger larvae were exposed to a series of OPO concentrations ranging from 0·05 to 0·30 mg/litre OPO (as total residual chlorine) at 25°C for 96 h. Mortality was used as the response parameter and results were quantitatively compared with the effects of chlorine-produced oxidants (CPO) obtained from the literature on these same developmental stages. Adult oysters (2- to 4-year class) were exposed to OPO concentrations ranging from 0·01 to 0·50 mg/litre at 15°C for 5 days and to the same concentration range at 25°C for two consecutive 6-day periods. Shell deposition and faecal matter accumulation were used as the response parameters for this stage.Straight-hinge larvae were significantly more sensitive to OPO than setting pediveliger larvae. Both larval stages were significantly more sensitive to CPO than to OPO. Shell deposition was significantly inhibited at all OPO concentrations for both 15°C and 25°C acclimated adult oysters. No significant differences were found between the shell deposition response of oysters at the two acclimation temperatures. Faecal matter accumulation was significantly reduced at OPO concentrations ≥ 0·05 mg/litre at both 15°C and 25°C. It was significantly (p < 0·05) greater for 25°C acclimated oysters than for 15°C acclimated oysters at OPO concentrations < 0·10 mg/litre but not at higher concentrations.  相似文献   

Sea urchin sperm bioassay for sewage and chlorinated seawater and its relation to fish bioassays     

Paul A. Dinnel  Quentin J. Stober  Dennis H. DiJulio 《Marine environmental research》1981,5(1):29-39

Bioassays were conducted with sea urchin and sand dollar sperm to determine the toxicity of chlorinated and unchlorinated sewage effluent and chlorinated and brominated seawater. The sperm cells were exposed to seawater dilutions of each toxicant for 5–15 min. The fertilisation of eggs served as the indicators of sperm viability. The effective concentrations which reduced fertilisation success by 50% (EC50) averaged 2·2 and 4·8% chlorinated and unchlorinated sewage in seawater, respectively. The sperm cells were extremely sensitive to chlorinated seawater at concentrations from 0·002 to 0·020 mg/litre total residual oxidant (TRO). Brominated seawater proved toxic to sperm in one test at 0·015 mg/litre TRO. Results of the sperm bioassays are compared with previous acute and chronic bioassays with fish.  相似文献   

Spatio-temporal distribution of dissolved inorganic carbon and net community production in the Chukchi and Beaufort Seas   总被引：2，自引：0，他引：2  

Nicholas R. Bates  Margaret H.P. Best  Dennis A. Hansell 《Deep Sea Research Part II: Topical Studies in Oceanography》2005,52(24-26):3303

As part of the 2002 Western Arctic Shelf–Basin Interactions (SBI) project, spatio-temporal variability of dissolved inorganic carbon (DIC) was employed to determine rates of net community production (NCP) for the Chukchi and western Beaufort Sea shelf and slope, and Canada Basin of the Arctic Ocean. Seasonal and spatial distributions of DIC were characterized for all water masses (e.g., mixed layer, halocline waters, Atlantic layer, and deep Arctic Ocean) of the Chukchi Sea region during field investigations in spring (5 May–15 June 2002) and summer (15 July–25 August 2002). Between these periods, high rates of phytoplankton production resulted in large drawdown of inorganic nutrients and DIC in the Polar Mixed Layer (PML) and in the shallow depths of the Upper Halocline Layer (UHL). The highest rates of NCP (1000–2850 mg C m⁻² d⁻¹) occurred on the shelf in the Barrow Canyon region of the Chukchi Sea and east of Barrow in the western Beaufort Sea. A total NCP rate of 8.9–17.8×10¹² g for the growing season was estimated for the eastern Chukchi Sea shelf and slope region. Very low inorganic nutrient concentrations and low rates of NCP (<15–25 mg C m⁻² d⁻¹) estimated for the mixed layer of the adjacent Arctic Ocean basin indicate that this area is perennially oligotrophic.  相似文献