О синергетическом феномене наноструктурного композита краситель–цеолит

Рассмотрены причины возникновения аномального эффекта люминесценции при создании нанокомпозита краситель–цеолитРозглянуто причини виникнення аномального ефекту люмінесценції при створенні нанокомпозиту барвник–цеоліт.The causes of the origin of an abnormal effect of luminescence at creating dye–zeolite nanocomposite are considered

Noroviruses in Archival Samples

Application of recent techniques to detect current pathogens in archival effluent samples collected and concentrated in 1987 lead to the characterization of norovirus GGII.6 Seacroft, unrecognized until 1990 in a clinical sample. Retrospective studies will likely increase our knowledge about waterborne transmission of emerging pathogens

Initiating guidance values for novel biological stability parameters in drinking water to control regrowth in the distribution system

Nine novel biological stability parameters for drinking water have been developed recently. Here, we report data for these nine parameters in treated water from 34 treatment plants in the Netherlands to deduce guidance values for these parameters. Most parameters did not show a strong correlation with another biological stability parameter in the same sample, demonstrating that most parameters hold different information on the biological stability of drinking water. Furthermore, the novel biological stability parameters in treated water varied considerably between plants and five parameters in treated water were significantly lower for drinking water produced from groundwater than surface water. The maximum biomass concentration (MBC7), cumulative biomass potential (CBP14) from the biomass production potential test (BPP-W) and the total organic carbon concentration in treated water from groundwater were predictive parameters for HPC22 and Aeromonas regrowth in the distribution system. Guidance values of 8.6 ng ATP L−1, 110 d·ng ATP L−1 and 4.1 mg C L−1 were deduced for these parameters, under which the HPC22 and Aeromonas numbers remain at regulatory level. The maximum biomass growth (MBG7) from the BPP-W test, the particulate and/or high molecular organic carbon and the iron accumulation rate in treated water from surface water were predictive parameters for HPC22 and Aeromonas regrowth in the distribution system. Deduced guidance values for these biological stability parameters were 4.5 ng ATP L−1, 47 μg C L−1 and 0.34 mg Fe m−2 day−1, respectively. We conclude from our study that a multiple parameter assessment is required to reliable describe the biological stability of drinking water, that the biological stability of drinking water produced from groundwater is described with other parameters than the biological stability of drinking water produced from surface water, and that guidance values for predictive biological stability parameters were inferred under which HPC22 and Aeromonas regrowth is under control

Biofilm composition and threshold concentration for growth of Legionella pneumophila on surfaces exposed to flowing warm tap water without disinfectant

Legionella pneumophila in potable water installations poses a potential health risk, but quantitative information about its replication in biofilms in relation to water quality is scarce. Therefore, biofilm formation on the surfaces of glass and chlorinated polyvinyl chloride (CPVC) in contact with tap water at 34 to 39°C was investigated under controlled hydraulic conditions in a model system inoculated with biofilm-grown L. pneumophila. The biofilm on glass (average steady-state concentration, 23 ± 9 pg ATP cm -2 ) exposed to treated aerobic groundwater (0.3 mg C liter -1 ; 1 μg assimilable organic carbon [AOC] liter -1 ) did not support growth of the organism, which also disappeared from the biofilm on CPVC (49 ± 9 pg ATP cm -2 ) after initial growth. L. pneumophila attained a level of 4.3 log CFU cm -2 in the biofilms on glass (1,055 ± 225 pg ATP cm -2 ) and CPVC (2,755± 460 pg ATP cm -2 ) exposed to treated anaerobic groundwater (7.9 mg C liter -1 ; 10 μg AOC liter -1 ). An elevated biofilm concentration and growth of L. pneumophila were also observed with tap water from the laboratory. The Betaproteobacteria Piscinibacter and Methyloversatilis and amoeba-resisting Alphaproteobacteria predominated in the clones and isolates retrieved from the biofilms. In the biofilms, the Legionella colony count correlated significantly with the total cell count (TCC), heterotrophic plate count, ATP concentration, and presence of Vermamoeba vermiformis. This amoeba was rarely detected at biofilm concentrations of <100 pg ATP cm -2 . A threshold concentration of approximately 50 pg ATP cm -2 (TCC = 1 × 106 to 2 × 106 cells cm -2 ) was derived for growth of L. pneumophila in biofilms

Biofilm composition and threshold concentration for growth of Legionella pneumophila on surfaces exposed to flowing warm tap water without disinfectant

Legionella pneumophila in potable water installations poses a potential health risk, but quantitative information about its replication in biofilms in relation to water quality is scarce. Therefore, biofilm formation on the surfaces of glass and chlorinated polyvinyl chloride (CPVC) in contact with tap water at 34 to 39°C was investigated under controlled hydraulic conditions in a model system inoculated with biofilm-grown L. pneumophila. The biofilm on glass (average steady-state concentration, 23 ± 9 pg ATP cm -2 ) exposed to treated aerobic groundwater (0.3 mg C liter -1 ; 1 μg assimilable organic carbon [AOC] liter -1 ) did not support growth of the organism, which also disappeared from the biofilm on CPVC (49 ± 9 pg ATP cm -2 ) after initial growth. L. pneumophila attained a level of 4.3 log CFU cm -2 in the biofilms on glass (1,055 ± 225 pg ATP cm -2 ) and CPVC (2,755± 460 pg ATP cm -2 ) exposed to treated anaerobic groundwater (7.9 mg C liter -1 ; 10 μg AOC liter -1 ). An elevated biofilm concentration and growth of L. pneumophila were also observed with tap water from the laboratory. The Betaproteobacteria Piscinibacter and Methyloversatilis and amoeba-resisting Alphaproteobacteria predominated in the clones and isolates retrieved from the biofilms. In the biofilms, the Legionella colony count correlated significantly with the total cell count (TCC), heterotrophic plate count, ATP concentration, and presence of Vermamoeba vermiformis. This amoeba was rarely detected at biofilm concentrations of -2 . A threshold concentration of approximately 50 pg ATP cm -2 (TCC = 1 × 106 to 2 × 106 cells cm -2 ) was derived for growth of L. pneumophila in biofilms. </p

Isolation and Detection of Enterovirus RNA from Large-Volume Water Samples by Using the NucliSens miniMAG System and Real-Time Nucleic Acid Sequence-Based Amplification

Concentration of water samples is a prerequisite for the detection of the low virus levels that are present in water and may present a public health hazard. The aim of this study was to develop a rapid, standardized molecular method for the detection of enteroviruses in large-volume surface water samples, using a concentration method suitable for the detection of infectious viruses as well as virus RNA. Concentration of water was achieved by a conventional filter adsorption-elution method and ultrafiltration, resulting in a 10,000-fold concentration of the sample. Isolation of virus RNA by a silica-based RNA extraction method was compared with the nonmagnetic and magnetic NucliSens RNA isolation methods. By using the silica-based RNA extraction method in two out of five samples, enterovirus RNA was detected, whereas four out of five samples were positive following RNA isolation with magnetic silica beads. Moreover, estimated RNA levels increased at least 100 to 500 times. Furthermore, we compared enterovirus detection by an in-house reverse transcription (RT)-PCR with a novel commercially available real-time nucleic acid sequence-based amplification (NASBA) assay. We found that the rapid real-time NASBA assay was slightly less sensitive than our in-house RT-PCR. The advantages, however, of a commercial real-time NASBA assay, like the presence of an internal control RNA, standardization, and enormous decrease in turnaround time, makes it an attractive alternative to RT-PCR

Wastewater samples.

<p>HCI = Health Care Institution, WWTP = Wastewater Treatment Plant</p><p>^aEffluents were obtained three (^*) or four (^ǂ) times during 2012.</p><p>Underlined years indicate that influents and effluents from the same year and location were sampled at the same time-point.</p><p>Wastewater samples.</p

Bacterial concentrations in surface waters (A) and waste water (B).

<p>For purpose of comparison with concentrations of ESBL-producing <i>E</i>. <i>coli</i> which were only determined in samples from 2010 onwards, in (A), samples taken prior to 2010 are indicated in black, and samples taken from 2010 onwards are indicated in white. In (B), grey symbols indicate HCI wastewater, black symbols indicate WWTP influents, and white symbols indicate WWTP effluents. Horizontal bars indicate median values. Samples with concentrations below the detection limit (<i>E</i>. <i>coli</i>: <10 cfu/ml, ESBL-<i>E</i>. <i>coli</i>:.<1.5 cfu/ml) are represented by symbols on the x-axis.</p

Surface water samples.

<p>^aA total of 113 samples were taken at 30 locations scattered over eight different regions (group A and group H contained different water bodies, but were located in the same regional area). For each group, the number of samples analysed per location is calculated by dividing the no. of samples by the no. of locations; this number also equals the number of different sampling dates per site.</p><p>Surface water samples.</p

Characteristics of ESBL-producing <i>E</i>. <i>coli</i> isolates from wastewater chains.

<p>* Am = ampicillin</p><p>Cx = cefotaxime</p><p>Cz = ceftazidime</p><p>Te = tetracyclin</p><p>St = streptomycin</p><p>Ci = ciprofloxacine</p><p>Na = nalidixic acid</p><p>Su = sulfamethoxazole</p><p>Tr = trimethoprim</p><p>Ch = chloramphenicol.</p><p>MICs were determined with Etests (Cz, Na, Su, Ch) and microbroth dilution (remainder of antimicrobials), resistance defined as MIC greater than or equal to the epidemiological cut-off (EUCAST).</p><p>Indicated in bold are pheno-/genotypes present in HCI and municipal wastewater.</p><p>Characteristics of ESBL-producing <i>E</i>. <i>coli</i> isolates from wastewater chains.</p