Biocorrosion and biofilm formation in a nutrient limited heating system subjected to alternating microaerophilic conditions

Severe biofilm formation and biocorrosion have been observed in heating systems even when the water quality complied with existing standards. The coupling between water chemistry, biofilm formation, species composition, and biocorrosion in a heating system was investigated by adding low concentrations of nutrients and oxygen under continuous and alternating dosing regimes. Molecular analysis of 16S rRNA gene fragments demonstrated that the amendments did not cause changes in the overall bacterial community composition. The combined alternating dosing of nutrients and oxygen caused increased rates of pitting (bio-) corrosion. Detection of bacteria involved in sulfide production and oxidation by retrieval of the functional dsrAB and apsA genes revealed the presence of Gram-positive sulfate- and sulfite-reducers and an unknown sulfur-oxidizer. Therefore, to control biocorrosion, sources of oxygen and nutrients must be limited, since the effect of the alternating operational conditions apparently is more important than the presence of potentially corrosive biofilm bacteria

Pendlingens sociale geografi: Transportmiddelvalg i lyset af pendlerens politiske holdninger, sociale normer og kultur

Danske pendlere kører fortrinsvist i bil – også i store byer som København. Når rejsetiden er 20 minutter i bil var der blandt pendlere bosiddende i Hovedstaden godt 15 % cyklister, 35 % bilister og 15 % i offentlig transport. De resterende 35 % var enten til fods eller vekslede mellem forskellige transportmidler fra dag til dag. Tilsvarende ved 20 minutter var andelene blandt sjællændere godt 5 % cyklister, 55 % bilister og godt 5 % i offentlig transport. Region Nord- og Midtjylland havde begge 5 % på cykel, 75 % i bil og 5 % i offentlig transport. I Syddanmark sås ved 20 minutters rejsetid 10 % cyklister, 60 % i bil og 5 % i bus/tog. Beregningerne er baseret på data fra en spørgeskemaundersøgelse blandt 2235 pendlere. Vi estimerede elasticitet i transportmiddelvalget med hensyn til rejsetid i bil. Rejsetiderne blev beregnet ved brug af Google Maps Distance Matrix. Pendlerne var alle i beskæftigelse, 18-65 år og med samme fordeling af køn, alder, geografi og uddannelse, som den danske baggrundsbefolkning. Desuden præsenteres en typologi afpendlere, der indeholder 4 overordnede grupperinger. “Bilister uden klare holdninger” (32 %), “grønne pendlere i storbyen” (30 %), “bilister der bor uden for de store byer” (23 %) og endelig ”anti-grønne bilister” (15 %). Denne opdeling i pendler-grupperinger indeholdt overraskende få holdninger og kultur

Comparison of the Population Excess Fraction of <i>Chlamydia trachomatis</i> Infection on Pelvic Inflammatory Disease at 12-months in the Presence and Absence of Chlamydia Testing and Treatment:Systematic Review and Retrospective Cohort Analysis

Background: The impact of Chlamydia trachomatis (chlamydia) control on the incidence of pelvic inflammatory disease (PID) is theoretically limited by the proportion of PID caused by chlamydia. We estimate the population excess fraction (PEF) of treated chlamydia infection on PID at 12-months in settings with widespread chlamydia control (testing and treatment) and compare this to the estimated PEF of untreated chlamydia. Methods: We used two large retrospective population-based cohorts of women of reproductive age from settings with widespread chlamydia control to calculate the PEF of treated chlamydia on PID at 12-months. We undertook a systematic review to identify further studies that reported the risk of PID in women who were tested for chlamydia (infected and uninfected). We used the same method to calculate the PEF in eligible studies then compared all estimates of PEF. Results: The systematic review identified a single study, a randomised control led trial of chlamydia screening (POPI-RCT). In the presence of testing and treatment <10% of PID at 12-months was attributable to treated (baseline) chlamydia infections (Manitoba: 8.86%(95%CI 7.15-10.75); Denmark: 3.84%(3.26-4.45); screened-arm POPI-RCT: 0.99%(0.00-29.06)). In the absence of active chlamydia treatment 26.44% (11.57-46.32) of PID at 12-months was attributable to untreated (baseline) chlamydia infections (deferred-arm POPI-RCT). The PEFs suggest that eradicating baseline chlamydia infections could prevent 484 cases of PID at 12-months per 100,000 women in the untreated setting and 13- 184 cases of PID per 100,000 tested women in the presence of testing and treatment. Conclusion: Testing and treating chlamydia reduced the PEF of chlamydia on PID by 65% compared to the untreated setting. But in the presence of testing and treatment over 90% of PID could not be attributed to a baseline chlamydia infection. More information is needed about the aetiology of PID to develop effective strategies for improving the reproductive health of women

COVID-19-krisen: Forløb og bekymringer: Artikel 1a

Denne artikel leverer en oversigt over og en gennemgang af de konkrete politiske indgreb, som den danske regering foretog med henblik på at opdæmme smittespredning i de første måneder af COVID-19-pandemien i Danmark 2020