A well resolved ODMR triplet minus singlet spectrum of P680 from PSII particles

AbstractAn ADMR T-S spectrum of the primary donor (P680) of photosystem II (PSII) was obtained from anaerobically photoreduced particles. The spectrum is the best resolved obtained so far having a main bleaching band at 684 nm with a linewidth of only 100 cm−1. The view that this spectrum is produced by native homogeneous P680 unlike those obtained before is defended. A small bleaching observed at 678 nm is discussed in terms of the reaction center structure. One possible interpretation of the observations is that P680 is a very loose dimer with an exciton splitting of only 144 cm−1 corresponding to a dimer center-to-center distance of roughly 11.5 Å

Finite Size Scaling Analysis of Biased Diffusion on Fractals

Diffusion on a T fractal lattice under the influence of topological biasing fields is studied by finite size scaling methods. This allows to avoid proliferation and singularities which would arise in a renormalization group approach on infinite system as a consequence of logarithmic diffusion. Within the scheme, logarithmic diffusion is proved on the basis of an analysis of various temporal scales such as first passage time moments and survival probability characteristic time. This confirms and puts on firmer basis previous renormalization group results. A careful study of the asymptotic occupation probabilities of different kinds of lattice points allows to elucidate the mechanism of trapping into dangling ends, which is responsible of the logarithmic time dependence of average displacement.Comment: 17 pages TeX, 3 Postscript figure

Successful treatment of long-standing post-stroke dysphagia with botulinum toxin and rehabilitation

Cricopharyngeal myotomy is the most common treatment used to restore normal swallowing in patients with persistent ( /6 months) cricopharyngeal muscle dysfunction post-stroke. We describe 2 patients whose dysphagia was due to cricopharyngeal muscle over-activity and who significantly improved after a percutaneous botulinum toxin injection in the cricopharyngeal muscle in combination with a rehabilitation treatment (dietary modifications, postural techniques, airflow protection manoeuvres). Swallowing was assessed clinically and by fibreoptic endoscopic evaluation of swallowing and videofluoroscopy; the degree of dysphagia was scored using the penetration-aspiration scale. Two months after the botulinum toxin injection the patients, who were previously fed via percutaneous endoscopic gastrostomy, returned to independent oral feeding and at 6, 12 and 24 month follow-up, both were still able to maintain an adequate oral intake with no signs of aspiration (by videofluoroscopy) or clinical complications. No further botulinum toxin injections or rehabilitation treatments were required. Our findings strongly suggest that even longstanding dysphagia can improve dramatically in selected patients. To the best of our knowledge, there are no other reports with such a long follow-up

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Plant Photosystem II and ODMR Spectroscopy of its Pigments

Natural photosystems, that are present in photosynthetic bacterial membranes and in thylakoids of algae and green plants, contain pigment molecules which are necessary for the three primary processes of Photosynthesis: - Light harvesting; - Energy transport to the Reaction Centre; - Primary charge separation. In the so-called Photosystem II (PSII) of plants, this complex pigment system is made up essentially by chlorophylls, pheophytins and carotenoids. There are about 300 chlorophyll molecules (a and b), more than 100 carotenoids (xanthophylls and beta-carotene) and a few molecules of pheophytin-a. The system can be studied by optical spectroscopy in the visible region, a main difficulty being the overlap of the pigment transitions in the red and blue regions where the most informative transitions of chlorophylls and carotenoids are present, In this report it will be shown how the association of optical spectroscopy and magnetic resonance in a double resonance spectroscopic technique known as Optically Detected Magnetic Resonance (ODMR) allows the above-mentioned difficulties to be partially overcome. On the one side, it is possible to assign optical transitions within unresolved bands to specific pigments selected by their magnetic resonances which have an intrinsically larger resolution. On the other hand, it is possible to study paths of excitonic energy within the pigment-protein complexes through the fluorescence response and to obtain interesting information about the function of the system. Some examples will be illustrated taken from recent experiments performed in our laboratory both on the antenna and on the reaction centre of PSII

Optically Detected Magnetic Resonance of pigments in Light Harvesting Complex (LHCII) of spinach

A global analysis of ADMR and FDMR experiments on LHCII complexes prepared from spinach leaves is performed. All results are reinterpreted and shown to be compatible with the presence of three specific xantophyll-chlorophyll interactions which are labeled by the xantophyll triplet ZFS and by detailed optical features in the Microwave Induced Absorption spectra