Sudbury project (University of Muenster-Ontario Geological Survey): Sr-Nd in heterolithic breccias and gabbroic dikes

One major objective of our Sudbury project was to define origin and age of the huge breccia units below and above the Sudbury Igneous Complex (SIC). The heterolithic Footwall Breccia (FB) represents a part of the uplifted crater floor. It contains subrounded fragments up to several meters in size and lithic fragments with shock features (greater than 10 GPa) embedded into a fine- to medium-grained matrix. Epsilon(sub Nd)-epsilon(sub Sr) relationships point to almost exclusively parautochthonous precursor lithologies. The different textures of the matrix reflect the metamorphic history of the breccia layer; thermal annealing by the overlying hot impact melt sheet (SIC) at temperatures greater than 1000 C resulted in melting of the fine crushed material, followed by an episode of metasomatic K-feldspar growth and, finally, formation of low-grade minerals such as actinolite and chlorite. Isotope relationships in the Onaping breccias (Gray and Green Member) are much more complex. All attempts to date the breccia formation failed: Zircons are entirely derived from country rocks and lack the pronounced Pb loss caused by the heat of the slowly cooling impact melt sheet (SIC). Rb-Sr techniques using either lithic fragments of different shock stages or the thin slab method, set time limits for the apparently pervasive alkali mobility in these suevitic breccias. The data array and the intercept in the plots point to a major Rb-Sr fractionation around 1.54 Ga ago. This model age is in the same range as the age obtained for the metasomatic matrix of the FB. Rb-Sr dating of a shock event in impact-related breccias seems to be possible only if their matrix had suffered total melting by the hot melt sheet (FB) or if they contain a high fraction of impact melt (suevitic Onaping breccias), whereas the degree of shock metamorphism in rock or lithic fragments plays a minor role. In the Sudbury case, however, the impact melt in the seuvitic breccias is devitrified and recrystallized, which changed Rb/Sr ratios quite drastically. Therefore, the Onaping breccias give only age limits for alteration and low-grade metamorphism. The Sm-Nd system was not reset during the Sudbury event; clasts as well as the matrix in the FB and in the Onaping breccias show preimpact 'Archean' Nd isotope signatures

Sudbury project (University of Muenster-Ontario Geological Survey): Petrology, chemistry, and origin of breccia formations

Within the Sudbury Project of the University of Muenster and the Ontario Geological Survey special emphasis was put on the breccia formations exposed at the Sudbury structure (SS) because of their crucial role for the impact hypothesis. They were mapped and sampled in selected areas of the north, east, and south ranges of the SS. The relative stratigraphic positions of these units are summarized. Selected samples were analyzed by optical microscopy, SEM, microprobe, XRF and INAA, Rb-Sr and SM-Nd-isotope geochemistry, and carbon isotope analysis. The results of petrographic and chemical analysis for those stratigraphic units that were considered the main structural elements of a large impact basin are summarized

Biochemical Characterization of the SPATE Members EspPα and EspI

The activity of serine proteases is influenced by their substrate specificity as well as by the physicochemical conditions. Here, we present the characterization of key biochemical features of the two SPATE members EspPα and EspI from Shiga-toxin producing Escherichia coli (STEC) and enterohemorrhagic E. coli (EHEC). Both proteases show high activity at conditions mimicking the human blood stream. Optimal activities were observed at slightly alkaline pH and low millimolar concentrations of the divalent cations Ca2+ and Mg2+ at physiological temperatures indicating a function in the human host. Furthermore, we provide the first cleavage profile for EspI demonstrating pronounced specificity of this protease.</p

Sudbury project (University of Muenster-Ontario Geological Survey): Summary of results - an updated impact model

In 1984 the Ontario Geological Survey initiated a research project on the Sudbury structure (SS) in cooperation with the University of Muenster. The project included field mapping (1984-1989) and petrographic, chemical, and isotope analyses of the major stratigraphic units of the SS. Four diploma theses and four doctoral theses were performed during the project (1984-1992). Specific results of the various investigations are reported. Selected areas of the SS were mapped and sampled: Footwall rocks; Footwall breccia and parts of the sublayer and lower section of the Sudbury Igneous Complex (SIC); Onaping Formation and the upper section of the SIC; and Sudbury breccia and adjacent Footwall rocks along extended profiles up to 55 km from the SIC. All these stratigraphic units of the SS were studied in substantial detail by previous workers. The most important characteristic of the previous research is that it was based either on a volcanic model or on a mixed volcanic-impact model for the origin of the SS. The present project was clearly directed toward a test of the impact origin of the SS without invoking an endogenic component. In general, our results confirm the most widely accepted stratigraphic division of the SS. However, our interpretation of some of the major stratigraphic units is different from most views expressed. The stratigraphy of the SS and its new interpretation is given as a basis for discussion

A five-year observance of changes in the cardiovascular risk profile in 505 HIV-positive individuals

Purpose: Since the introduction of antiretroviral therapy (ART) and the extension of life expectancy, HIV-infected persons have shown an increasing number of cardiovascular events. The reduction of cardiovascular risk factors becomes a new challenge in HIV care. One of the main objectives of the HIV&amp;HEART study is to examine the development of cardiovascular risk factors and treatment of cardiovascular diseases. Methods: This study is an on-going, prospective, regional multicentre trial that was conducted to analyse the frequency and clinical course of cardiac disorders as well as cardiovascular risk factors in HIV-infected patients. 505 HIV-infected outpatients were recruited at baseline (BL) and re-examined during 5-year follow up (5YFU). Results: 84% of 505 eligible HIV-infected patients were male. The average age was 44.3&#x00B1;9.5 years at BL. The proportion of ART-treated patients increased from 85.7% at BL to 96.4% at 5YFU. During the 5-year observation period mean cardiovascular risk detected by Framingham score increased from 6% at BL to 10% at 5YFU. Even after adjusting for age there was a difference in the Framingham score of 2%. Between BL and 5YFU systolic blood pressure increased from 128.4&#x00B1;19.8 mmHg to 138.3&#x00B1;19.9 mmHg in spite of an intensified use of antihypertensive drugs, from 11.9% at BL to 24.0% at 5YFU. The rate of participants with adiposity, characterised by a BMI&#x3E;30, increased from 7.9% at BL to 11.2% at 5YFU. Lipid-lowering therapy was applied in 10.3% of the patients at BL and in 13.9% at 5YFU. Triglycerides (TAG)&#x2265;200 mg/dl reduced from 38.9% at BL to 36.8% at 5YFU; in contrast cholesterol values&#x2265;200 mg/dl elevated from 57.8% to 61.8%. The same trend was observed in HDL&#x2264;40 mg/dl. Here we found a change from 29.2% versus 31.3%. Doing regular sports elevated from 1.9% to 3.3%. The count of smokers increased for 2.8% and also mean pack-years changes from 24 to 26.5 pack-years. Conclusion: During a 5-year period the cardiovascular risk in Framingham score increased disproportionately high in this HIV-infected cohort even after adjusting for age. There was an increasing blood pressure although an elevated use of antihypertensive therapy. There was also a tendency of elevating BMI and an increasing trend in smoking behavior. As protective facts, we found a tendency in doing sports and a decreasing TAG value during intensifying lipid-lowering therapy. Cardiovascular risk was increasing, in spite of interventions

Higher rates of triple-class virological failure in perinatally HIV-infected teenagers compared with heterosexually infected young adults in Europe

Objectives The aim of the study was to determine the time to, and risk factors for, triple-class virological failure (TCVF) across age groups for children and adolescents with perinatally acquired HIV infection and older adolescents and adults with heterosexually acquired HIV infection. Methods We analysed individual patient data from cohorts in the Collaboration of Observational HIV Epidemiological Research Europe (COHERE). A total of 5972 participants starting antiretroviral therapy (ART) from 1998, aged 500 HIV-1 RNA copies/mL despite >= 4 months of use. TCVF was defined as cumulative failure of two NRTIs, an NNRTI and a bPI. Results The median number of weeks between diagnosis and the start of ART was higher in participants with perinatal HIV infection compared with participants with heterosexually acquired HIV infection overall [17 (interquartile range (IQR) 4-111) vs. 8 (IQR 2-38) weeks, respectively], and highest in perinatally infected participants aged 10-14 years [49 (IQR 9-267) weeks]. The cumulative proportion with TCVF 5 years after starting ART was 9.6% [95% confidence interval (CI) 7.0-12.3%] in participants with perinatally acquired infection and 4.7% (95% CI 3.9-5.5%) in participants with heterosexually acquired infection, and highest in perinatally infected participants aged 10-14 years when starting ART (27.7%; 95% CI 13.2-42.1%). Across all participants, significant predictors of TCVF were those with perinatal HIV aged 10-14 years, African origin, pre-ART AIDS, NNRTI-based initial regimens, higher pre-ART viral load and lower pre-ART CD4. Conclusions The results suggest a beneficial effect of starting ART before adolescence, and starting young people on boosted PIs, to maximize treatment response during this transitional stage of development

CD4 cell count and the risk of AIDS or death in HIV-Infected adults on combination antiretroviral therapy with a suppressed viral load: a longitudinal cohort study from COHERE.

BACKGROUND: Most adults infected with HIV achieve viral suppression within a year of starting combination antiretroviral therapy (cART). It is important to understand the risk of AIDS events or death for patients with a suppressed viral load. METHODS AND FINDINGS: Using data from the Collaboration of Observational HIV Epidemiological Research Europe (2010 merger), we assessed the risk of a new AIDS-defining event or death in successfully treated patients. We accumulated episodes of viral suppression for each patient while on cART, each episode beginning with the second of two consecutive plasma viral load measurements 500 copies/µl, the first of two consecutive measurements between 50-500 copies/µl, cART interruption or administrative censoring. We used stratified multivariate Cox models to estimate the association between time updated CD4 cell count and a new AIDS event or death or death alone. 75,336 patients contributed 104,265 suppression episodes and were suppressed while on cART for a median 2.7 years. The mortality rate was 4.8 per 1,000 years of viral suppression. A higher CD4 cell count was always associated with a reduced risk of a new AIDS event or death; with a hazard ratio per 100 cells/µl (95% CI) of: 0.35 (0.30-0.40) for counts <200 cells/µl, 0.81 (0.71-0.92) for counts 200 to <350 cells/µl, 0.74 (0.66-0.83) for counts 350 to <500 cells/µl, and 0.96 (0.92-0.99) for counts ≥500 cells/µl. A higher CD4 cell count became even more beneficial over time for patients with CD4 cell counts <200 cells/µl. CONCLUSIONS: Despite the low mortality rate, the risk of a new AIDS event or death follows a CD4 cell count gradient in patients with viral suppression. A higher CD4 cell count was associated with the greatest benefit for patients with a CD4 cell count <200 cells/µl but still some slight benefit for those with a CD4 cell count ≥500 cells/µl

HIV pre-exposure prophylaxis during the SARS-CoV-2 pandemic: Results from a prospective observational study in Germany.

Aims: Since 2017, HIV pre-exposure prophylaxis (PrEP) care has been provided through an intersectoral collaboration at WIR (Walk-in-Ruhr, Center for Sexual Health and Medicine, Bochum, Germany). The aim of this study was to establish possible impact of COVID-restrictions on the sexual behavior of PrEP users in North Rhine-Westphalia. Methods: The current PrEP study collected data of individuals using PrEP, their sexual behavior and sexually transmitted infections (STIs) before (each quarter of year 2018) and during the COVID-19 pandemic (each quarter of year 2020). Results: During the first lockdown in Germany from mid-March until May 2020, PrEP-care appointments at WIR were postponed or canceled. Almost a third of PrEP users had discontinued their PrEP intake in the 2nd quarter of 2020 due to alteration of their sexual behavior. The number of sexual partners decreased from a median of 14 partners in the previous 6 months in 1st quarter of 2020, to 7 partners in 4th quarter of 2020. Despite such a significant reduction in partner number during the pandemic in comparison to the pre-pandemic period, a steady rate of STIs was observed among PrEP users in 2020. Conclusion: The SARS-CoV-2-pandemic has impacted PrEP-using MSM in North Rhine-Westphalia with respect to their PrEP intake regimen and sexual behavior in 2020. Our study revealed a steady rate of STI among PrEP users even during the pandemic, thus highlighting the importance of ensuring appropriate HIV/STI prevention services in times of crisis