Survival, biofilm formation, and growth potential of environmental and enteric escherichia coli strains in drinking water microcosms

E. coli is the most commonly used indicator for faecal contamination in a drinking water distribution system (WDS). The assumption is that E. coli are of enteric origin and cannot persist for long outside their host, therefore acting as indicators of recent contamination events. This study investigates the fate of E. coli in drinking water; specifically addressing survival, biofilm formation under shear stress, and regrowth in a series of laboratory-controlled experiments. We show the extended persistence of three E. coli strains (two enteric and one soil isolate) in sterile and non-sterile drinking water microcosms, at 8 and 17°C, with T90 values ranging from 17.4 ± 1.8 to 149 ± 67.7 days, using standard plate counts and a series of (RT)-Q-PCR assays targeting 16S rRNA, tuf, uidA, and rodA genes and transcripts. Furthermore, each strain was capable of attaching to a surface and replicating to form biofilm in the presence of nutrients under a range of shear stress values (0.6, 2.0, and 4.4 dyn cm-2; BioFlux, Fluxion); however, cell numbers did not increase when drinking water was flowed over (t-test; p > 0.05). Finally, E. coli regrowth within drinking water microcosms containing PE-100 pipe-wall material was not observed in the biofilm or water phase using a combination of culturing and Q-PCR methods for E. coli. The results of this work highlight that when E. coli enters drinking water it has the potential to survive and attach to surfaces but that regrowth within drinking water or biofilm is unlikely

Galaxies with Spiral Structure up to z = 0.87 --Limits on M/L and the Stellar Velocity Dispersion

We consider seven distant galaxies with clearly evident spiral structure from HST images. Three of these were chosen from Vogt et al. (1996) (VFP) and have measured rotational velocities. Five were chosen from the Medium Deep Survey and are studied in Sarajedini et al. 1996 (SGGR), and one galaxy is found in both papers. We place upper limits on their mass-to-light ratios (M/L) by computing M/L_B for a maximal disk. We find that these galaxies have maximal disk mass-to-light ratios M/L_B = 1.5 - 3.5 M_sol/L_Bsol at the low end, but within the range seen in nearby galaxies. The mass-to-light ratios are low enough to suggest that the galaxies contain a young, rapidly formed stellar population. By using a Toomre stability criterion for formation of spiral structure, we place constraints on the ratio of M/L to the stellar velocity dispersion. If these galaxies have maximal disks they would have to be nearly unstable so as to have small enough velocity dispersions that their disks are not unrealistically thick. This suggests that there is a substantial amount of dark matter present in the luminous regions of the galaxy.Comment: AAS Latex + PS Figure, accepted for publication in A

Ex vivo expansion and differentiation of erythroblasts: From culture dishes to stirred tank reactors for the production of red blood cells

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Observational Constraints on Disk Heating as a Function of Hubble Type

Current understanding of the secular evolution of galactic disks suggests that this process is dominated by two or more heating mechanisms, which increase the random motions of stars in the disk. In particular, the gravitational influence of giant molecular clouds and irregularities in the spiral potential have been proposed to explain the observed velocity dispersions in the solar neighborhood. Each of these mechanisms acts on different components of the stellar velocities, which affects the ratio of the vertical and radial components of the stellar velocity dispersion since the relative strengths of giant molecular clouds and spiral irregularities vary with Hubble type. A study of this ratio as function of Hubble type has the potential to provide strong constraints on disk heating mechanisms. We present major and minor axis stellar kinematics for four spiral galaxies of Hubble type from Sa to Sbc, and use the data to infer the ratios sigma_z/sigma_R in the galaxy disks. The results combined with two galaxies studied previously and with Milky Way data show that the ratio is generally in the range 0.5 - 0.8. There is a marginally significant trend of decreasing ratio with advancing Hubble type, consistent with the predictions of disk heating theories. However, the errors on individual measurements are large, and the absence of any trend is consistent with the data at the 1-sigma level. As a byproduct of our study, we find that three of the four galaxies in our sample have a central drop in their stellar line-of-sight velocity dispersion, a phenomenon that is increasingly observed in spiral galaxies. [ABRIDGED]Comment: 24 pages, LaTeX, 5 Postscript figures, to appear in AJ (Dec 2003

Klimaateffecten op de Natura 2000 moerascorridor, Quick Scan in het Groene Hart

Dit onderzoek is uitgevoerd om antwoord te vinden op de volgende vraag: Welke gevolgen heeft klimaatverandering op eutrofiëring, verdroging en verzilting in acht Natura 2000 gebieden in het Groene Hart? De hydrologische gegevens zijn ontleend aan de acht gebieden: Naardermeer, Botshol, Oostelijke Binnenpolder van Tienhoven, Molenpolder, Groot Wilnis Vinkeveen, Nieuwkoop en Noorden, Oukoop en Krimpenerwaar

Sexual Concerns after (Pelvic) Radiotherapy: Is There Any Role for the Radiation Oncologist?

INTRODUCTION: Sexual function is an important aspect of quality of life, and may be impaired after (pelvic) radiation. AIM: The aim of this study was to identify practice, responsibility attitudes, knowledge, and barriers of Dutch radiation oncologists regarding sexual counseling. METHODS: A cross-sectional survey was performed using a 28-item questionnaire sent to all members of the Dutch Society for Radiotherapy and Oncology. MAIN OUTCOME MEASURES: Self-reported practice, knowledge, barriers, need for training and responsibility attitudes in regard to demographic characteristics. RESULTS: Of the surveyed sample, 54.6% of the radiation oncologists completed the instrument (n = 119). Frequency of discussing sexual function was fluctuating, depending on the type of tumor. The majority of the responding radiation oncologists (75%) agreed that discussing sexual function is their responsibility, about one-third (33.6%) pointed at the involved specialist (surgeon, urologist, gynecologist, or oncologist), a fifth also considered the general practitioner responsible (21%). Additional training about discussing sexuality was required according to 44.4%, the majority agreed that sexual counseling should be a regular component of radiation oncology residency (n = 110, 94%). Barriers most mentioned included patient is too ill (36.2%), no angle or reason for asking (32.4%), advanced age of the patient (27%) and culture/religion (26.1%). For prostate cancer patients, phosphodiesterase 5 inhibitor information was supplied regularly (49.2%) and often (40.7%). CONCLUSIONS: Radiation oncologists generally perform sexual counseling in case of pelvic radiation therapy, but not consistently in case of gastrointestinal, breast, and other cancers. The majority of radiation oncologists considered counseling on sexual functioning as a part of their job, some also pointed at the referring specialist or general practitioner. The findings suggest that awareness about sexual dysfunction is present among radiation oncologists, but responsibility for active counseling is uncertain. Results emphasize the need for providing educational and practical training, as well as a list for specialized referral. Krouwel EM, Nicolai MP, van der Wielen GJ, Putter H, Krol ADG, Pelger RCM, Incrocci L, and Elzevier HW. Sexual concerns after (pelvic) radiotherapy: is there any role for the radiation oncologist? J Sex Med 2015;12:1927-1939.Development and application of statistical models for medical scientific researc

HappyHier: hoe gelukkig is men waar? : Gegevensverzameling en bepaling van de invloed van het type grondgebruik, deel I

This study set out to measure what influence the type of environment has on how happy people say they feel at a certain moment in time, with the aim of formulating rules for quantifying the effect of spatial changes on wellbeing. A smartphone app was developed for use by a broad sample population in the Netherlands, with push notifications prompting people to report how they felt at a certain moment. From 1 May to 28 July of 2016, 4318 unique participants made use of this HappyHier app, filling in at least one questionnaire on location. The results show that people are happier outdoors than indoors. And when they are outdoors, they are happier in predominantly natural surroundings than in more built-up areas. Moreover, from the ratings given to the surroundings, it can be concluded that they have a more positive effect when the participants found them more restful or stimulating. People’s impressions of the beauty of their surroundings had less influenc

2020 ESC Guidelines on acute coronary syndrome without ST-segment elevation Recommendations and critical appraisal from the Dutch ACS and Interventional Cardiology working groups

Recently, the European Society of Cardiology (ESC) has updated its guidelines for the management of patients with acute coronary syndrome (ACS) without ST-segment elevation. The current consensus document of the Dutch ACS working group and the Working Group of Interventional Cardiology of the Netherlands Society of Cardiology aims to put the 2020 ESC Guidelines into the Dutch perspective and to provide practical recommendations for Dutch cardiologists, focusing on antiplatelet therapy, risk assessment and criteria for invasive strategy.</p

Scanning tunneling microscopy and spectroscopy at low temperatures of the (110) surface of Te doped GaAs single crystals

We have performed voltage dependent imaging and spatially resolved spectroscopy on the (110) surface of Te doped GaAs single crystals with a low temperature scanning tunneling microscope (STM). A large fraction of the observed defects are identified as Te dopant atoms which can be observed down to the fifth subsurface layer. For negative sample voltages, the dopant atoms are surrounded by Friedel charge density oscillations. Spatially resolved spectroscopy above the dopant atoms and above defect free areas of the GaAs (110) surface reveals the presence of conductance peaks inside the semiconductor band gap. The appearance of the peaks can be linked to charges residing on states which are localized within the tunnel junction area. We show that these localized states can be present on the doped GaAs surface as well as at the STM tip apex.Comment: 8 pages, 8 figures, accepted for publication in PR