Deformation Quantization of a Certain Type of Open Systems

We give an approach to open quantum systems based on formal deformation quantization. It is shown that classical open systems of a certain type can be systematically quantized into quantum open systems preserving the complete positivity of the open time evolution. The usual example of linearly coupled harmonic oscillators is discussed.Comment: Major update. Improved main statements. 21 page

Inverting Time-Dependent Harmonic Oscillator Potential by a Unitary Transformation and a New Class of Exactly Solvable Oscillators

A time-dependent unitary (canonical) transformation is found which maps the Hamiltonian for a harmonic oscillator with time-dependent real mass and real frequency to that of a generalized harmonic oscillator with time-dependent real mass and imaginary frequency. The latter may be reduced to an ordinary harmonic oscillator by means of another unitary (canonical) transformation. A simple analysis of the resulting system leads to the identification of a previously unknown class of exactly solvable time-dependent oscillators. Furthermore, it is shown how one can apply these results to establish a canonical equivalence between some real and imaginary frequency oscillators. In particular it is shown that a harmonic oscillator whose frequency is constant and whose mass grows linearly in time is canonically equivalent with an oscillator whose frequency changes from being real to imaginary and vice versa repeatedly.Comment: 7 pages, 1 figure include

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

Background: Many patients with COVID-19 have been treated with plasma containing anti-SARS-CoV-2 antibodies. We aimed to evaluate the safety and efficacy of convalescent plasma therapy in patients admitted to hospital with COVID-19. Methods: This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]) is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. The trial is underway at 177 NHS hospitals from across the UK. Eligible and consenting patients were randomly assigned (1:1) to receive either usual care alone (usual care group) or usual care plus high-titre convalescent plasma (convalescent plasma group). The primary outcome was 28-day mortality, analysed on an intention-to-treat basis. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936. Findings: Between May 28, 2020, and Jan 15, 2021, 11558 (71%) of 16287 patients enrolled in RECOVERY were eligible to receive convalescent plasma and were assigned to either the convalescent plasma group or the usual care group. There was no significant difference in 28-day mortality between the two groups: 1399 (24%) of 5795 patients in the convalescent plasma group and 1408 (24%) of 5763 patients in the usual care group died within 28 days (rate ratio 1·00, 95% CI 0·93–1·07; p=0·95). The 28-day mortality rate ratio was similar in all prespecified subgroups of patients, including in those patients without detectable SARS-CoV-2 antibodies at randomisation. Allocation to convalescent plasma had no significant effect on the proportion of patients discharged from hospital within 28 days (3832 [66%] patients in the convalescent plasma group vs 3822 [66%] patients in the usual care group; rate ratio 0·99, 95% CI 0·94–1·03; p=0·57). Among those not on invasive mechanical ventilation at randomisation, there was no significant difference in the proportion of patients meeting the composite endpoint of progression to invasive mechanical ventilation or death (1568 [29%] of 5493 patients in the convalescent plasma group vs 1568 [29%] of 5448 patients in the usual care group; rate ratio 0·99, 95% CI 0·93–1·05; p=0·79). Interpretation: In patients hospitalised with COVID-19, high-titre convalescent plasma did not improve survival or other prespecified clinical outcomes. Funding: UK Research and Innovation (Medical Research Council) and National Institute of Health Research

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication

Contamination of pear concentrate by Alicyclobacillus from recirculating flume water during fruit concentrate production

Alicyclobacillus and viable aerobic counts were monitored at nine different production stages of pear concentrate, with the functioning of either a recirculating or a one-pass flume water system. Significantly (P < 0.05) higher levels of Alicyclobacillus were detected in the final pasteurized product (102-104°C for 90 s) when the recirculating flume water system was operational. An average of 1.19 Log10 c.f.u. ml-1 vegetative cells and 1.35 Log10 c.f.u. ml-1 endospores were recovered, whereas 0 c.f.u. ml-1 vegetative cells and endospores were detected when the one-pass flume water system was operational. Alicyclobacillus levels did not differ significantly (P > 0.05) in condensate water during the functioning of the two flume water systems, with 1.81 Log10 c.f.u. ml-1 vegetative cells and 1.01 Log10 c.f.u. ml-1 endospores (recirculating system) and 0.78 Log10 c.f.u. ml-1 vegetative cells and 0.42 Log10 c.f.u. ml-1 endospores (one-pass system) recovered, respectively. As a result, water treatment protocols should be established if untreated recirculating flume or condensate water is to be used in order to prevent Alicyclobacillus contamination and accumulation in the processing environment. © 2011 Springer Science+Business Media B.V.Article in Pres

Prevention of the accumulation of Alicyclobacillus in apple concentrate by restricting the continuous process running time

Aims: To study the accumulation of vegetative cells and endospores of Alicyclobacillus, as well as viable aerobic counts during the continuous production of apple juice concentrate. Methods and Results: Apples were processed for a continuous process running time of 108h (processing rate 1·8-2·0th-1) without clean-in-place (CIP) procedures in-between different batches. Samples from single-strength apple juice, concentrate after evaporation (±30°Brix), the final product (concentrate pasteurized at 102-104°C for 90s) and condensate water (by-product of the juice concentration process) were collected every 12h. From 12 to 84h of processing, vegetative Alicyclobacillus counts in single-strength apple juice increased significantly (P<0·05) from 1 to 3·15log10CFUml-1. Accumulation patterns of vegetative cells in apple concentrate and the final product were similar from 24 to 84h of processing, with the respective counts increasing from 0·13 to 1·63 and 0·01 to 1·69log10CFUml-1. The highest Alicyclobacillus endospore counts in single-strength juice, concentrate and the final product was at 84h of processing with 1·32, 1·59 and 1·64log10CFUml-1, respectively. Conclusions: Alicyclobacillus vegetative cells and endospores accumulate in fruit concentrates during a continuous process running time of 108h. Significance and Impact of the Study: In conjunction with good manufacturing practices, fruit concentrate manufactures can minimize Alicyclobacillus accumulation in fruit concentrates by limiting the continuous process running time between clean-ups to under 84h. © 2011 Stellenbosch University. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.Articl