The Occurrence and Characterization of Hemoglobin from Different Strains of Genetically Diverse, Free-Living Frankia

Hemoglobins have been identified in root nodules of many actinorhizal plants. When cultured in vitro, the actinomycete Frankia strain CcI3 produces hemoglobin when grown with or without supplied nitrogen. The cyanobacterium, Nostoc commune, also produces hemoglobin in vitro, although only under nitrogen-fixing, microaerobic conditions, and in less than one fifth of the explored strainslspecies. The objectives of this study were to determine if Frankia strains EANlpec, ArI3, EUNlf, CcI.17, and Cc13, members of diverse genogroups, are capable of producing hemoglobin in vitro, to characterize the oxygen kinetics of the hemoglobin, and to determine the effect of nitrogen, oxygen, and carbon dioxide on the amount of hemoglobin produced. Frankia cells were disrupted under an atmosphere of carbon monoxide and the carbonmonoxy absorption spectrum of the crude extract was used to calculate the hemoglobin concentration in the cells. Hemoglobin was present in all five strains when grown on nitrogen-free (-N) or nitrogen-supplied (+N) medium. Thus it is likely that hemoglobins are produced by most Frankia strains. In four of the five strains, the hemoglobin concentrations were similar in -N and +N culture. This does not support an association between nitrogen fixation and hemoglobin expression. Hemoglobin in crude extracts from -N cultures of EANlPec was partially purified by ion exchange chromatography and then subjected to size exclusion chromatography. The molecular mass, 13.4 f 0.2 kDa (mean * SE, n = 3), is consistent with that of truncated hemoglobins, such as the Nostoc hemoglobin. The hemoglobin in other EANlPec ion exchange fractions was further purified using a CO-pressurized concentration cell with a 10 kDa exclusion membrane. The absorption spectra obtained from this sample showed carbonmonoxy and oxyhemoglobin absorption peaks typical of a hemoglobin. This same sample was also used to determine the hff value for oxygen; 131.2 f 5.8 s-\u27 (mean * SE, n = 6) and 166 + 8.2 s (mean * SE, n = 7) for the hemoglobin from -N and +N cultures, respectively. Cultures of EANlp grown at 2% and 20% 0 2 showed no effect of 0 2 on hemoglobin concentration in the +N treatments @ = 0.632). The -N treatments showed less growth than the +N treatments and the hemoglobin concentration was greater at 2% than 20% 0 2 . -Cultures of Frankia strain EANlPec and CcI3 grew more efficiently when supplied with 0.2% C02 when compared to 0.0% C02. This suggests that addition of C02 to cultures could assist in Frankia growth at low initial densities, such as isolation from root nodules. The very rapid oxygen dissociation rate of EANlp hemoglobin is two to threefold faster than that of Frankia strain CcI3 and Nostoc hemoglobin, which have been proposed to function in facilitated diffusion of oxygen. If hemoglobin is localized within the small volume of the vesicle or periphery of the cells, the concentrations in the immediate region in which it is found might approach those necessary for facilitated oxygen transport

Automated VR therapy for improving positive self-beliefs and psychological well-being in young patients with psychosis: a proof of concept evaluation of Phoenix VR self-confidence therapy

Background: Low self-confidence in patients with psychosis is common. This can lead to higher symptom severity, withdrawal from activities, and low psychological well-being. There are effective psychological techniques to improve positive self-beliefs but these are seldom provided in psychosis services. With young people with lived experience of psychosis we developed a scalable automated VR therapy to enhance positive-self beliefs. Aims: The aim was to conduct a proof of concept clinical test of whether the new VR self-confidence therapy (Phoenix) may increase positive self-beliefs and psychological well-being. Method: Twelve young patients with non-affective psychosis and with low levels of positive self-beliefs participated. Over 6 weeks, patients were provided with a stand-alone VR headset so that they could use Phoenix at home and were offered weekly psychologist meetings. The outcome measures were the Oxford Positive Self Scale (OxPos), Brief Core Schema Scale, and Warwick-Edinburgh Well-being Scale (WEMWBS). Satisfaction, adverse events and side-effects were assessed. Results: Eleven patients provided outcome data. There were very large end-of-treatment improvements in positive self-beliefs (OxPos mean difference = 32.3; 95% CI: 17.3, 47.3; Cohen’s d=3.0) and psychological well-being (WEMWBS mean difference = 11.2; 95% CI: 8.0, 14.3; Cohen’s d=1.5). Patients rated the quality of the VR therapy as: excellent (n=9), good (n=2), fair (n=0), poor (n=0). An average of 5.3 (SD=1.4) appointments were attended. Conclusions: Uptake of the VR intervention was high, satisfaction was high, and side-effects extremely few. There were promising indications of large improvements in positive self-beliefs and psychological well-being. A randomized controlled clinical evaluation is warranted

Randomised controlled trial of automated VR therapy to improve positive self-beliefs and psychological well-being in young people diagnosed with psychosis: a study protocol for the Phoenix VR self-confidence therapy trial

Introduction The confidence of young people diagnosed with psychosis is often low. Positive self-beliefs may be few and negative self-beliefs many. A sense of defeat and failure is common. Young people often withdraw from many aspects of everyday life. Psychological well-being is lowered. Psychological techniques can improve self-confidence, but a shortage of therapists means that very few patients ever receive such help. Virtual reality (VR) offers a potential route out of this impasse. By including a virtual coach, treatment can be automated. As such, delivery of effective therapy is no longer reliant on the availability of therapists. With young people with lived experience, we have developed a staff-assisted automated VR therapy to improve positive self-beliefs (Phoenix). The treatment is based on established cognitive behavioural therapy and positive psychology techniques. A case series indicates that this approach may lead to large improvements in positive self-beliefs and psychological well-being. We now aim to conduct the first randomised controlled evaluation of Phoenix VR. Methods and analysis 80 patients with psychosis, aged between 16 and 30 years old and with low levels of positive self-beliefs, will be recruited from National Health Service (NHS) secondary care services. They will be randomised (1:1) to the Phoenix VR self-confidence therapy added to treatment as usual or treatment as usual. Assessments will be conducted at 0, 6 (post-treatment) and 12 weeks by a researcher blind to allocation. The primary outcome is positive self-beliefs at 6 weeks rated with the Oxford Positive Self Scale. The secondary outcomes are psychiatric symptoms, activity levels and quality of life. All main analyses will be intention to treat. Ethics and dissemination The trial has received ethical approval from the NHS Health Research Authority (22/LO/0273). A key output will be a high-quality VR treatment for patients to improve self-confidence and psychological well-being. Trial registration number ISRCTN10250113

Steep Faint-end Slopes of Galaxy Mass and Luminosity Functions at z>=6 and the Implications for Reionisation

We present the results of a numerical study comparing photometric and physical properties of simulated z=6-9 galaxies to the observations taken by the WFC3 instrument aboard the Hubble Space Telescope. Using cosmological hydrodynamical simulations we find good agreement with observations in color-color space at all studied redshifts. We also find good agreement between observations and our Schechter luminosity function fit in the observable range, Muv<= -18, provided that a moderate dust extinction effect exists for massive galaxies. However beyond what currently can be observed, simulations predict a very large number of low-mass galaxies and evolving steep faint-end slopes from alpha_L = -2.15 at z=6 to alpha_L = -2.64 at z=9, with a dependence of |alpha_L| \propto (1+z)^0.59. During the same epoch, the normalization phi* increases and the characteristic magnitude Muv* becomes moderately brighter with decreasing redshift. We find similar trends for galaxy stellar mass function with evolving low-mass end slope from alpha_M = - 2.26 at z=6 to alpha_M = -2.87 at z=9, with a dependence of |alpha_M| \propto (1+z)^0.65. Together with our recent result on the high escape fraction of ionizing photons for low-mass galaxies, our results suggest that the low-mass galaxies are important contributor of ionizing photons for the reionisation of the Universe at z>=6.Comment: Revised metadata, 16 pages, 5 tables, 17 figures. MNRAS, in pres

Can helmet design reduce the risk of concussion in football?

Of all sports, football accounts for the highest incidence of concussion in the US due to the large number of athletes participating and the nature of the sport. While there is general agreement that concussion incidence can be reduced through rule changes and teaching proper tackling technique, there remains debate as to whether helmet design may also reduce the incidence of concussion. A retrospective analysis was performed of head impact data collected from 1833 collegiate football players who were instrumented with helmet-mounted accelerometer arrays for games and practices. Data were collected between 2005 and 2010 from 8 collegiate football teams: Virginia Tech, University of North Carolina, University of Oklahoma, Dartmouth College, Brown University, University of Minnesota, Indiana University, and University of Illinois. Concussion rates were compared between players wearing Riddell VSR4 and Riddell Revolution helmets while controlling for the head impact exposure of each player. A total of 1,281,444 head impacts were recorded, from which 64 concussions were diagnosed. The relative risk of sustaining a concussion in a Revolution helmet compared with a VSR4 helmet was 46.1% (95% CI 28.1%–75.8%). When controlling for each player’s exposure to head impact, a significant difference was found between concussion rates for players in VSR4 and Revolution helmets (χ2 = 4.68, p = 0.0305). This study illustrates that differences in the ability to reduce concussion risk exist between helmet models in football. Although helmet design may never prevent all concussions from occurring in football, evidence illustrates that it can reduce the incidence of this injury

Tilted black hole accretion disc models of Sagittarius A*: time-variable millimetre to near-infrared emission

High-resolution, multi-wavelength, and time-domain observations of the Galactic centre black hole candidate, Sgr A*, allow for a direct test of contemporary accretion theory. To date, all models have assumed alignment between the accretion disc and black hole angular momentum axes, but this is unjustified for geometrically thick accretion flows like that onto Sgr A*. Instead, we calculate images and spectra from a set of simulations of accretion flows misaligned ('tilted') by 15 degrees from the black hole spin axis and compare them with millimetre (mm) to near-infrared (NIR) observations. Non-axisymmetric standing shocks from eccentric fluid orbits dominate the emission, leading to a wide range of possible image morphologies. These effects invalidate previous parameter estimates from model fitting, including estimates of the dimensionless black hole spin, except possibly at low values of spin or tilt. At 1.3mm, the images have crescent morphologies, and the black hole shadow may still be accessible to future mm-VLBI observations. Shock heating leads to high energy electrons (T > 10^12 K), which can naturally produce the observed NIR flux, spectral index, and rapid variability ('flaring'). This NIR emission is uncorrelated with that in the mm, which also agrees with observations. These are the first models to self-consistently explain the time-variable mm to NIR emission of Sgr A*. Predictions of the model include significant structural changes observable with mm-VLBI on both the dynamical (hour) and Lense-Thirring precession (day-year) timescales; and ~30-50 microarcsecond changes in centroid position from extreme gravitational lensing events during NIR flares, detectable with the future VLT instrument GRAVITY. If the observed NIR emission is caused by shock heating in a tilted accretion disc, then the Galactic centre black hole has a positive, non-zero spin parameter (a > 0).Comment: 17 pages, 18 figures, submitted to MNRAS; for movies and version with high-res figures see http://astro.berkeley.edu/~jdexter/tiltedsgr

Theory and Applications of Non-Relativistic and Relativistic Turbulent Reconnection

Realistic astrophysical environments are turbulent due to the extremely high Reynolds numbers. Therefore, the theories of reconnection intended for describing astrophysical reconnection should not ignore the effects of turbulence on magnetic reconnection. Turbulence is known to change the nature of many physical processes dramatically and in this review we claim that magnetic reconnection is not an exception. We stress that not only astrophysical turbulence is ubiquitous, but also magnetic reconnection itself induces turbulence. Thus turbulence must be accounted for in any realistic astrophysical reconnection setup. We argue that due to the similarities of MHD turbulence in relativistic and non-relativistic cases the theory of magnetic reconnection developed for the non-relativistic case can be extended to the relativistic case and we provide numerical simulations that support this conjecture. We also provide quantitative comparisons of the theoretical predictions and results of numerical experiments, including the situations when turbulent reconnection is self-driven, i.e. the turbulence in the system is generated by the reconnection process itself. We show how turbulent reconnection entails the violation of magnetic flux freezing, the conclusion that has really far reaching consequences for many realistically turbulent astrophysical environments. In addition, we consider observational testing of turbulent reconnection as well as numerous implications of the theory. The former includes the Sun and solar wind reconnection, while the latter include the process of reconnection diffusion induced by turbulent reconnection, the acceleration of energetic particles, bursts of turbulent reconnection related to black hole sources as well as gamma ray bursts. Finally, we explain why turbulent reconnection cannot be explained by turbulent resistivity or derived through the mean field approach.Comment: 66 pages, 24 figures, a chapter of the book "Magnetic Reconnection - Concepts and Applications", editors W. Gonzalez, E. N. Parke

Timing of Concussion Diagnosis Is Related to Head Impact Exposure Prior to Injury

Concussions are commonly undiagnosed in an athletic environment because the post-injury signs and symptoms may be mild, masked by the subject, or unrecognized. This study compares measures of head impact frequency, location and kinematic response prior to cases of immediate and delayed concussion diagnosis

Head Impact Exposure Sustained by Football Players on Days of Diagnosed Concussion

This study compares the frequency and severity of head impacts sustained by football players on days with and without diagnosed concussion and to identify the sensitivity and specificity of single impact severity measures to diagnosed injury

Investigation of hospital discharge cases and SARS-CoV-2 introduction into Lothian care homes

Background The first epidemic wave of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in Scotland resulted in high case numbers and mortality in care homes. In Lothian, over one-third of care homes reported an outbreak, while there was limited testing of hospital patients discharged to care homes. Aim To investigate patients discharged from hospitals as a source of SARS-CoV-2 introduction into care homes during the first epidemic wave. Methods A clinical review was performed for all patients discharges from hospitals to care homes from 1st March 2020 to 31st May 2020. Episodes were ruled out based on coronavirus disease 2019 (COVID-19) test history, clinical assessment at discharge, whole-genome sequencing (WGS) data and an infectious period of 14 days. Clinical samples were processed for WGS, and consensus genomes generated were used for analysis using Cluster Investigation and Virus Epidemiological Tool software. Patient timelines were obtained using electronic hospital records. Findings In total, 787 patients discharged from hospitals to care homes were identified. Of these, 776 (99%) were ruled out for subsequent introduction of SARS-CoV-2 into care homes. However, for 10 episodes, the results were inconclusive as there was low genomic diversity in consensus genomes or no sequencing data were available. Only one discharge episode had a genomic, time and location link to positive cases during hospital admission, leading to 10 positive cases in their care home. Conclusion The majority of patients discharged from hospitals were ruled out for introduction of SARS-CoV-2 into care homes, highlighting the importance of screening all new admissions when faced with a novel emerging virus and no available vaccine