Microwave stray radiation losses in vacuum windows

Vacuum windows are required in magnetically confined fusion experiments to provide possibilities to observe the plasma in a wide range of electromagnetic wavelengths. The window disk consists of a dielectric, e.g. Fused Silica (SiO$_2$), Sapphire or Chemically Vapourised Diamond (CVD). As electromagnetic waves pass through the disk, a fraction of the beam power is dissipated resulting in a temperature increase of the disk. In Electron Cyclotron Waves (ECW) heated plasmas the dissipation in the window disk can be very high. The computation of dielectric losses for a collimated beam with known incidence angle, polarisation and loss tangent (measure for the intrinsic dielectric loss) is well established. However, the dielectric losses in diagnostic windows mostly result from microwave stray radiation, which results from a modest, but inevitable, fraction of non-absorbed ECW. This fraction diffuses in the vessel by many reflections into rays with random k-vector and with random polarisation. In this work the thermal load on the window disk by microwave stray radiation is assessed. The load by a collimated beam is studied as a function of incidence angle and polarisation allowing to average over a distribution of incident rays. An experiment was commissioned measuring the loss tangent of a number of commercially available SiO$_2$ disks at low power in an open resonator, and subsequently measuring the dielectric heating of these disks at high power stray radiation using the facility ’MISTRAL’ at Wendelstein-7X. The experimental results are compared to modelling and it is demonstrated that, in the parameter range considered, single-pass fractional absorption may be applied while taking a safety margin that arises from the minima and maxima due to multiple reflections

Road Traffic Noise and Incident Myocardial Infarction: A Prospective Cohort Study

BACKGROUND Both road traffic noise and ambient air pollution have been associated with risk for ischemic heart disease, but only few inconsistent studies include both exposures. METHODS In a population-based cohort of 57 053 people aged 50 to 64 years at enrolment in 1993-1997, we identified 1600 cases of first-ever MI between enrolment and 2006. The mean follow-up time was 9.8 years. Exposure to road traffic noise and air pollution from 1988 to 2006 was estimated for all cohort members from residential address history. Associations between exposure to road traffic noise and incident MI were analysed in a Cox regression model with adjustment for air pollution (NO(x)) and other potential confounders: age, sex, education, lifestyle confounders, railway and airport noise. RESULTS We found that residential exposure to road traffic noise (L(den)) was significantly associated with MI, with an incidence rate ratio IRR of 1.12 per 10 dB for both of the two exposure windows: yearly exposure at the time of diagnosis (95% confidence interval (CI): 1.02-1.22) and 5-years time-weighted mean (95% CI: 1.02-1.23) preceding the diagnosis. Visualizing of the results using restricted cubic splines showed a linear dose-response relationship. CONCLUSIONS Exposure to long-term residential road traffic noise was associated with a higher risk for MI, in a dose-dependent manner

Association of Sleep Duration with Chronic Diseases in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study

Background: In view of the reduced number of hours devoted to sleep in modern western societies the question arises what effects might result from sleep duration on occurrence of chronic diseases. Methods: Data from 23 620 middle-aged participants of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study, that were recruited between 1994–1998, were analyzed by using Cox proportional hazard regression to examine the association between self-reported sleep duration at baseline and incidence of chronic diseases, such as diabetes, myocardial infarction, stroke, and cancer. Results: During a mean follow-up period of 7.8 years 841 incident cases of type 2 diabetes, 197 cases of myocardial infarction, 169 incident strokes, and 846 tumor cases were observed. Compared to persons sleeping 7-,8 h/day, participants with sleep duration of,6 h had a significantly increased risk of stroke (Hazard Ratio (HR) = 2.06, 95

STAGES IN THE ORIGIN OF VERTEBRATES: ANALYSIS BY MEANS OF SCENARIOS

Vertebrates lack an epidermal nerve plexus. This feature is common to many invertebrates from which vertebrates differ by an extensive set of shared-derived characters (synapomorphies) derived from the neural crest and epidermal neurogenic placodes. Hence, the hypothesis that the developmental precursor of the epidermal nerve plexus may be homologous to the neural crest and epidermal neurogenic placodes. This account attempts to generate a nested set of scenarios for the prevertebrate-vertebrate transition, associating a presumed sequence of behavioural and environmental changes with the observed phenotypic ones. Toward this end, it integrates morphological, developmental, functional (physiological/behavioural) and some ecological data, as many phenotypic shifts apparently involved associated transitions in several aspects of the animals. The scenarios deal with the origin of embryonic and adult tissues and such major organs as the notochord, the CNS, gills and kidneys and propose a sequence of associated changes. Alternative scenarios are stated as the evidence often remains insufficient for decision. The analysis points to gaps in comprehension of the biology of the animals and therefore suggests further research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72629/1/j.1469-185X.1989.tb00471.x.pd

Sleep-disordered breathing-do we have to change gears in heart failure?

The majority of patients with heart failure have sleep-disordered breathing (SDB)-with central (rather than obstructive) sleep apnoea becoming the predominant form in those with more severe disease. Cyclical apnoeas and hypopnoeas are associated with sleep disturbance, hypoxaemia, haemodynamic changes, and sympathetic activation. Such patients have a worse prognosis than those without SDB. Mask-based therapies of positive airway pressure targeted at SDB can improve measures of sleep quality and partially normalise the sleep and respiratory physiology, but recent randomised trials of cardiovascular outcomes in central sleep apnoea have been neutral or suggested the possibility of harm, likely from increased sudden death. Further randomised outcome studies (with cardiovascular mortality and hospitalisation endpoints) are required to determine whether mask-based treatment for SDB is appropriate for patients with chronic systolic heart failure and obstructive sleep apnoea, for those with heart failure with preserved ejection fraction, and for those with decompensated heart failure. New therapies for sleep apnoea-such as implantable phrenic nerve stimulators-also require robust assessment. No longer can the surrogate endpoints of improvement in respiratory and sleep metrics be taken as adequate therapeutic outcome measures in patients with heart failure and sleep apnoea

X ray screening identifies active site and allosteric inhibitors of SARS CoV 2 main protease

The coronavirus disease COVID 19 caused by SARS CoV 2 is creating tremendous human suffering. To date, no effective drug is available to directly treat the disease. In a search for a drug against COVID 19, we have performed a high throughput x ray crystallographic screen of two repurposing drug libraries against the SARS CoV 2 main protease Mpro , which is essential for viral replication. In contrast to commonly applied x ray fragment screening experiments with molecules of low complexity, our screen tested already approved drugs and drugs in clinical trials. From the three dimensional protein structures, we identified 37 compounds that bind to Mpro. In subsequent cell based viral reduction assays, one peptidomimetic and six nonpeptidic compounds showed antiviral activity at nontoxic concentrations. We identified two allosteric binding sites representing attractive targets for drug development against SARS CoV