Abstract. Spatial and kinematical correlations between the H i and12 CO(2−1) emission of the southern spiral galaxy NGC 4945 are studied with a common angular resolution of ∼23 (corresponding to 750 pc at D = 6.7 Mpc) and a velocity resolution of ∼7 km s −1 . The 1.4 GHz continuum emission is also observed. The H i kinematics yield a galaxy mass of ∼1.4×1011 M within radius R = 380 , with molecular and neutral atomic gas each contributing ∼2%, respectively. A central continuum source of size 7 . 6 × 3 . 4 (250 × 110 pc) is enveloped by a molecular cloud of mass 1.5 × 10 9 M for R ≤ 7 . 5, and is rapidly rotating with Vrot ∼ 160 km s −1 . H i emission from the central region at velocities |V −Vsys| > 200 km s −1 may be related to optically detected gas that is believed to trace an outflow directed towards the halo. Nuclear H i absorption at V -Vsys ∼ +80 km s −1 suggests inflow towards the centre, that was so far only seen in molecular lines. H i features at each end of the major axis (|R| ∼ 600 ) are interpreted as spiral arms that are viewed tangentially and that also cause prominent emission features in the radio continuum, H i, and CO further inside the galaxy. A central elongated region showing non-circular motions is interpreted as a bar which fuels the nuclear starburst. The H i and CO position-velocity data have been analysed using linear resonance theory, and possible locations of resonances are identified.
Introduction Healthcare workers’ work performance and mental health are associated with positive mental health outcomes and directly related to increased productivity and decreased disability costs. Methods We conducted a systematic review to identify factors associated with work performance of healthcare workers during a pandemic and conducted a meta-analysis of the prevalence of mental health outcomes in this context. Primary papers were collected and analysed using the Population/Intervention/Comparison/Outcome framework and using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. To critically appraise the studies included in the review, we used the AXIS appraisal tool to assess each cross-sectional study’s quality. Results The study identified nine factors associated with the work performance and mental health of healthcare workers, including experiencing feelings of depression, anxiety, having inadequate support, experiencing occupational stress, decreased productivity, lack of workplace preparedness, financial concerns associated with changes in income and daily living, fear of transmission and burnout/fatigue. Conclusion There is a rapidly rising need to address the work performance and mental health of healthcare workers providing timely care to patients. Regular and sustained interventions, including the use of information and communication technologies such as telehealth, are warranted.
Lactate dehydrogenase from the hyperthermophilic bacterium Thermotoga maritima has been functionally expressed in Escherichia coli. As shown by gel-permeation chromatography, dynamic light scattering, and ultracentrifugation, the recombinant protein forms homotetrameric and homooctameric assemblies with identical spectral properties and a common subunit molecular mass (35 kDa). Dynamic light scattering and sedimentation equilibrium experiments proved that both species are monodisperse, thus excluding their interconversion in the given ranges of concentration (0.02 -50 mg/ml) and temperature (20-SOOC). Rechromatography confirms this finding : the octamer does not dissociate at low enzyme concentrations, nor do tetramers dimerize at the given upper limit of concentration. Renaturation of pure tetramers or octamers after preceding guanidine denaturation leads to redistribution of the two species ; increased temperature favors octamer formation.Thermal analysis and denaturation by chaotropic agents do not allow the free energies of stabilization of the two forms to be quantified, because heat coagulation and kinetic partitioning between reconstitution and aggregation cause irreversible side reactions. Guanidine denaturation of the octamer leads to a highly cooperative dissociation to tetramers which subsequently dissociate and unfold to yield metastable dimers and, finally, fully unfolded monomers. Evidently, there is no tight coupling of the two tetramers within the stable octameric quaternary structure. Electron microscopy clearly corroborates this conclusion : image processing shows that the dumb-bell-shaped octamer is made up of two tetramers connected via surface contacts without significant changes in the dimensions of the constituent parts.Keywords: hyperthermophiles ; lactate dehydrogenase; quaternary structure ; stability ; Thermotoga muritimu.Lactate dehydrogenases (LDH) are dimeric or tetrameric enzymes that require their native quaternary structure for catalysis (Jaenicke, 1974). As has been shown by denaturation-renaturation experiments, using domain fragments and intact subunits of porcine skeletal muscle LDH, tertiary and quaternary interactions provide increments of stability which in toto yield the exceedingly high value for the free energy of stabilization observed for the enzyme (Miiller et al., 1982;Pfeil, 1986; Opitz et al., 1987;Jaenicke, 1991). This supports the general view that protein stability is accomplished by the cumulative effect of covalent and non-covalent bonds at the various levels of the hierarchy of protein structure (Vita et al.. 1989;Jaenicke, 1996).There are various enzymes from thermophilic (and hyperthermophilic) organisms that exhibit anomalously high states of association, which suggests thermal adaptation of proteins to be attributable to higher states of subunit assembly. For example, pyruvate dehydrogenase from Bacillus stearothermophilus (To,, ~6 5°C ) contains four times as many polypeptide chains comCorrespondence ta R. Jaenicke, lnstitut
Personalised health care is an evolution, moving away from a disease-focused model of care, translating scientific and technological advances into benefits for patients, and placing them at the centre of the patients' health and care. Companion diagnostics emerge as a very specific and special group of in vitro diagnostics among the different technologies shaping the personalised health care spectrum. Companion diagnostics provide highly valuable information, allowing patients, health practitioners and payers to decide with a higher level of certainty on the potential benefits of a treatment or care pathway. Decreasing uncertainty may result in a more efficient selection of treatments and care, targeted at subpopulations that are most likely to benefit. Companion diagnostics account for a minimal portion of the already small expenditure on in vitro diagnostics (far less than 1% of total health care expenditure), and yet they provide the means to limit inefficient use of health care resources while optimising patient outcomes. It is clear that equal access to personalised health care is still an issue across the EU. One of the most common perceived barriers is affordability. The investment in companion diagnostics can provide long-term value for patients and health care systems, shifting resources to areas of need. Health systems do not fully recognise yet the value that companion diagnostics bring to make personalised health care more affordable across the EU. This inhibits patient access to personalised treatments and care, preventing improved outcomes. In many countries, market access frameworks for diagnostic tests are fragmented and not aligned with specific funding and reimbursement mechanisms, discouraging the use of these tests. Emerging evidence shows that patients are missing out on the appropriate tests and treatments while a reduction in the inefficient use of health care resources is not realised. This article outlines some of these market access barriers for companion diagnostics in the EU, including reimbursement challenges specific to some member states (Germany, the UK, and France). Furthermore, proposals addressing barriers and increasing timely patient access to companion diagnostics in the EU are presented.
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