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A number of Healthcare Practitioners (HCPs), mostly from Black, Asian and minority ethnic (BAME) origin have died with COVID-19. This survey aimed to explore the views of an ethnically diverse sample of HCPs in the UK about COVID-19-related deaths among HCPs in general and BAME HCPs in particular.It is a cross-sectional prospective survey of HCPs in UK and was conducted online using Google Forms between 28th April and 4th May 2020.A total of 1119 UK HCPs (aged 45.0 ± 9.5 years, 56% males, 71% BAME) participated. Seventy-two per cent of respondents reported being worried about COVID-19 and 84% had concerns about personal protective equipment (PPE). Almost all (93%) respondents felt that inadequate PPE may be a contributory factor to HCP deaths. Half of the respondents, especially younger and BAME, reported feeling unable to say 'no', if asked to work without adequate PPE. BAME HCPs were considered at a higher-risk of acquiring coronavirus and dying with COVID-19. Reasons for excess BAME HCP deaths were believed to be comorbidities, inadequate PPE and working in high-risk areas. Majority (81%) of respondents felt that the government has been slow to respond to COVID-19 related deaths in HCPs and 67% HCPs were of the opinion that BAME workers with risk factors should be removed from direct clinical care.HCPs have significant COVID-19-related concerns. BAME HCPs are considered at increased risk due to comorbidities, working in high-risk areas, and inadequate PPE. BAME HCP should have a thorough risk assessment and high-risk HCPs may need work adjustment or redeployment. All HCPs must have appropriate training and provision of PPE.

Pulmonary gas exchange is the primary function of the lung, and during my lifetime, its measurement has passed through many stages. When I was born, many physiologists still believed that the lung secreted oxygen. When I was a medical student, the only way we had to recognize defective gas exchange was whether the patient was cyanosed. The advent of the oximeter soon showed that this sign could be very misleading. A breakthrough was the introduction of blood gas electrodes that could measure the PO 2, PCO 2, and pH of a small sample of arterial blood. It was soon recognized that the commonest cause of hypoxemia was ventilation‐perfusion inequality, and that this could also be responsible for CO 2 retention. In the early days, the understanding of the mechanisms of pulmonary gas exchange relied on graphical analysis because the oxygen and carbon dioxide dissociation curves are nonlinear and interdependent which precluded algebraic methods. However, with the introduction of digital computing, problems that had hitherto been impossible to tackle became amenable to study. A key advance was the development of the Multiple Inert Gas Elimination Technique. Now, noninvasive methods for measuring gas exchange show promise, and the whole subject continues to develop.

African Americans have higher rates of asthma prevalence, morbidity, and mortality in comparison with other racial groups. We sought to characterize endotypes of childhood asthma severity in African American patients in an inner-city pediatric asthma population. Baseline blood neutrophils, blood eosinophils, and 38 serum cytokine levels were measured in a sample of 235 asthmatic children (6-17 years) enrolled in the NIAID (National Institute of Allergy and Infectious Diseases)-sponsored Asthma Phenotypes in the Inner City (APIC) study (ICAC (Inner City Asthma Consortium)-19). Cytokines were quantified using a MILLIPLEX panel and analyzed on a Luminex analyzer. Patients were classified as Easy-to-Control or Difficult-to-Control based on the required dose of controller medications over one year of prospective management. A multivariate variable selection procedure was used to select cytokines associated with Difficult-to-Control versus Easy-to-Control asthma, adjusting for age, sex, blood eosinophils, and blood neutrophils. In inner-city African American children, 12 cytokines were significant predictors of Difficult-to-Control asthma (n = 235). CXCL-1, IL-5, IL-8, and IL-17A were positively associated with Difficult-to-Control asthma, while IL-4 and IL-13 were positively associated with Easy-to-Control asthma. Using likelihood ratio testing, it was observed that in addition to blood eosinophils and neutrophils, serum cytokines improved the fit of the model. In an inner-city pediatric population, serum cytokines significantly contributed to the definition of Difficult-to-Control asthma endotypes in African American children. Mixed responses characterized by TH2 (IL-5) and TH17-associated cytokines were associated with Difficult-to-Control asthma. Collectively, these data may contribute to risk stratification of Difficult-to-Control asthma in the African American population.

Investigation of the effects of various cycles of compression and decompression on the alveolar volumes of the excised lungs of sea lions and dogs. The results obtained include the finding that, in comparison to dog lungs, sea lion lungs empty more completely on mild compression and much more completely on severe compression. These findings support Scholander's (1940) hypothesis that some marine mammals are protected from decompression sickness by cartilaginous reinforcement of the small airways which permits alveolar emptying during a dive, so isolating compressed gas from pulmonary capillary blood.

The recognition of barometric pressure was a critical step in the development of environmental physiology. In 1644, Evangelista Torricelli described the first mercury barometer in a remarkable letter that contained the phrase, “We live submerged at the bottom of an ocean of the element air, which by unquestioned experiments is known to have weight.” This extraordinary insight seems to have come right out of the blue. Less than 10 years before, the great Galileo had given an erroneous explanation for the related problem of pumping water from a deep well. Previously, Gasparo Berti had filled a very long lead vertical tube with water and showed that a vacuum formed at the top. However, Torricelli was the first to make a mercury barometer and understand that the mercury was supported by the pressure of the air. Aristotle stated that the air has weight, although this was controversial for some time. Galileo described a method of measuring the weight of the air in detail, but for reasons that are not clear his result was in error by a factor of about two. Torricelli surmised that the pressure of the air might be less on mountains, but the first demonstration of this was by Blaise Pascal. The first air pump was built by Otto von Guericke, and this influenced Robert Boyle to carry out his classical experiments of the physiological effects of reduced barometric pressure. These were turning points in the early history of high-altitude physiology.

Threshold photoelectron spectroscopy (TPES) has been used to study flowing nitrogen subjected to a microwave discharge. The first three photoelectron (PE) bands of nitrogen corresponding to the ionizations N-2(+) (X-2 Sigma(+)(g)) v(+)

Relative partial photoionization cross-sections and angular distribution parameters, beta, have been measured for the first, I(+)((3)P(2))--I((2)P(3/2)), and fourth, I(+)((1)D(2))--I((2)P(3/2)), (5p)(-1) photoelectron (PE) bands of atomic iodine, by performing angle-resolved constant-ionic-state (CIS) measurements on these PE bands in the photon energy range 11.0-23.0 eV. Three Rydberg series, two ns and one nd series, which converge to the I(+) (3)P(1) limit at 11.33 eV and four Rydberg series, two ns and two nd series, which converge to the I(+) (1)D(2) limit at 12.15 eV were observed in the first PE band CIS spectra. The fourth band CIS spectrum showed structure in the 12.9-14.1 eV photon energy range, which is also seen in the first band CIS spectra. This structure arises from excitation to ns and nd Rydberg states that are parts of series converging to the I(+) (1)S(0) limit we reported on earlier, as well as 5s--5p excitations in the photon energy range 17.5-22.5 eV. These atomic iodine CIS spectra show reasonably good agreement with the equivalent spectra obtained for atomic bromine. The beta-plots for the first PE band recorded up to the I(+) (3)P(1) and I(+) (1)D(2) limits only show resonances corresponding to some of the 5p--nd excitations observed in the first band CIS spectra scanned to the I(+) (1)D(2) limit (12.15 eV). These plots are interpreted in terms of an angular momentum transfer model with the positive values of beta obtained on resonances corresponding to parity allowed j(t)=1 and 3 channels and the off-resonance negative beta values corresponding to parity unfavored channels, where j(t) is the quantum number for angular momentum transfer between the molecule, and the ion and photoelectron. The beta-plots recorded for iodine are significantly different from those obtained for atomic bromine. Comparison of the experimental CIS spectra and beta-plots with available theoretical results highlights the need for higher level calculations which include factors such as configuration interaction in the initial and final states, relativistic effects including spin-orbit interaction, and autoionization via resonant Rydberg states.

Avian pulmonary capillaries differ from those of mammals in three important ways. The blood-gas barrier is much thinner, it is more uniform in thickness, and the capillaries are far more rigid when their transmural pressure is altered. The thinness of the barrier is surprising because it predisposes the capillaries to stress failure. A possible mechanism for these differences is that avian pulmonary capillaries, unlike mammalian, are supported from the outside by air capillaries, but the details of the support are poorly understood. To clarify this we studied the blood and air capillaries in chicken lung using transmission electron microscopy (EM) and two relatively new techniques that allow 3D visualization: electron tomography and serial block-face scanning EM. These studies show that the pulmonary capillaries are flanked by epithelial bridges composed of two extremely thin epithelial cells with large surface areas. The junctions of the bridges with the capillary walls show thickening of the epithelial cells and an accumulation of extracellular matrix. Collapse of the pulmonary capillaries when the pressure outside them is increased is apparently prevented by the guy wire-like action of the epithelial bridges. The enlarged junctions between the bridges and the walls could provide a mechanism that limits the hoop stress in the capillary walls when the pressure inside them is increased. The support of the pulmonary capillaries may also be explained by an interdependence mechanism whereby the capillaries are linked to a rigid assemblage of air capillaries. These EM studies show the supporting structures in greater detail than has previously been possible, particularly in 3D, and they allow a more complete analysis of the mechanical forces affecting avian pulmonary capillaries.

Ibn al-Nafis (1213–1288) was an Arab physician who made several important contributions to the early knowledge of the pulmonary circulation. He was the first person to challenge the long-held contention of the Galen School that blood could pass through the cardiac interventricular septum, and in keeping with this he believed that all the blood that reached the left ventricle passed through the lung. He also stated that there must be small communications or pores ( manafidh in Arabic) between the pulmonary artery and vein, a prediction that preceded by 400 years the discovery of the pulmonary capillaries by Marcello Malpighi. Ibn al-Nafis and another eminent physiologist of the period, Avicenna (ca. 980–1037), belong to the long period between the enormously influential school of Galen in the 2nd century, and the European scientific Renaissance in the 16th century. This is an epoch often given little attention by physiologists but is known to some historians as the Islamic Golden Age. Its importance is briefly discussed here.

Photoionization spectra have been recorded in the $4s$, $4p$, and $3d$ resonance regions for the Kr I isoelectronic sequence using both the dual laser produced plasma (DLP) technique (at DCU) to produce photoabsorption spectra, and the merged ion beam and synchrotron radiation technique (at ASTRID) to measure absolute photoionization cross sections. Profile parameters are compared for the $4s\text{\ensuremath{-}}np$ resonances of ${\mathrm{Rb}}^{+}$ and ${\mathrm{Sr}}^{2+}$. Many $4p\ensuremath{\rightarrow}ns$, $md$ transitions are identified with the aid of Hartree-Fock calculations, and consistent quantum defects are observed for the various $ns$ and $md$ Rydberg series. Absolute single and double photoionization cross sections recorded in the $3d$ region for ${\mathrm{Rb}}^{+}$ and ${\mathrm{Sr}}^{2+}$ ions show preferential decay via double photoionization. This is only the second report to our knowledge where both the DLP technique and the merged-beam technique have been used simultaneously to record photoionization spectra, and the advantages of both techniques (i.e., better resolution in the case of DLP and values for absolute photoionization cross sections in the case of the merged-beam technique) are highlighted.

Background Climbers on the summit of Mt. Everest are exposed to extreme hypoxia, and the physiological implications are of great interest. Inferences have been made from alveolar gas samples collected on the summit, but arterial blood samples would give critical information. We propose a plan to insert an arterial catheter at an altitude of 8000 m, take blood samples above this using an automatic sampler, store the samples in glass syringes in an ice-water slurry, and analyze them lower on the mountain 4 to 6 hours later. Results A preliminary design of the automatic sampler was successfully tested at the White Mountain Research Station (altitude 3800 m – 4300 m). To determine how much the blood gases changed over a long period, rabbit blood was tonometered to give a gas composition close to that expected on the summit (PO2 4.0 kPa (30 mmHg), PCO2 1.3 kPa (10 mmHg), pH 7.7) and the blood gases were measured every 2 hours for 8 hours both at sea level and 3800 m. The mean changes were PO2 +0.3 to +0.4 kPa (+2 to +3 mmHg), PCO2 0 to +0.13 kPa (+1 mmHg), pH -0.02 to -0.04, base excess -0.7 to -1.2 mM. In practice the delay before analysis should not exceed 4 to 6 hours. The small paradoxical rise in PO2 is presumably caused mainly by contamination of the blood with air. Conclusion We conclude that automatic arterial blood sampling at high altitude is technically feasible and that the changes in the blood gases over a period of several hours are acceptably small.

An initial investigation of the photoionization behaviour of S atoms and SH radicals has been made in the gas-phase using angle resolved photoelectron spectroscopy (PES) with radiation from the Elettra synchrotron as the photon source. Angular distributions and relative photoionization cross-sections have been measured for S and SH as a function of photon energy from threshold (similar to10.3 eV) to 21.64 eV. The ionizations considered are S+(S-4)

The absolute cross section for photoionization of Cr+ has been measured using the merged-beam technique, focusing on the region of the 'giant' resonance. These new absolute data differ considerably from previous experimental data, with the result that the agreement between experiment and existing calculations has improved substantially. The neutral and ionized Cr spectra, previously believed to be completely different, are shown here to be rather similar. The role of the 3d5(6S) state in determining the special position of Cr among the 3d elements is emphasized. The experimental data are available at http://www.phys.au.dk/amo/atomphys/atomphys.htm.

We present measurements on the absolute photoionization cross section of doubly-charged Ca ions in the photon energy range 50-70 eV, which encompasses resonances of the type 3s→np. The energy dependence of the continuum cross section differs from the earlier measurement by van Kampen et al (1997), but is reproduced quite well by a recent R-matrix calculation (Wilson et al 1999), although the estimates of the oscillator strengths of the resonance lines are too low.

Absolute photoionization cross sections are presented for Mg+ ions in the photon energy range 25-160 eV. The assignments of the structures seen are discussed and compared with earlier assignments derived from photographic measurements. Good agreement is found with theoretical calculations of the continuum cross section, whereas the agreement with calculations of the oscillator strengths and of the line positions is less satisfactory.

Verbanck, Sylvia, Hans Larsson, Dag Linnarsson, G. Kim Prisk, John B. West, and Manuel Paiva. Pulmonary tissue volume, cardiac output and diffusing capacity in sustained microgravity. J. Appl. Physiol. 83(3): 810–816, 1997.—In microgravity (μG) humans have marked changes in body fluids, with a combination of an overall fluid loss and a redistribution of fluids in the cranial direction. We investigated whether interstitial pulmonary edema develops as a result of a headward fluid shift or whether pulmonary tissue fluid volume is reduced as a result of the overall loss of body fluid. We measured pulmonary tissue volume (Vti), capillary blood flow, and diffusing capacity in four subjects before, during, and after 10 days of exposure to μG during spaceflight. Measurements were made by rebreathing a gas mixture containing small amounts of acetylene, carbon monoxide, and argon. Measurements made early in flight in two subjects showed no change in Vti despite large increases in stroke volume (40%) and diffusing capacity (13%) consistent with increased pulmonary capillary blood volume. Late in-flight measurements in four subjects showed a 25% reduction in Vti compared with preflight controls ( P < 0.001). There was a concomittant reduction in stroke volume, to the extent that it was no longer significantly different from preflight control. Diffusing capacity remained elevated (11%; P< 0.05) late in flight. These findings suggest that, despite increased pulmonary perfusion and pulmonary capillary blood volume, interstitial pulmonary edema does not result from exposure to μG.

A mass spectrometer was designed specially for clinical respiratory investigation (Fowler, 1957) and it has been in use for general tests of lung function for three years. It performs continuous automatic gas analysis, and has a gas-sampling tube of only about I mm. external diameter at its tip. This fine sampling tube, which is placed at the patient's lips during general tests of lung function, has now been adapted so that it can be inserted down a bronchoscope into any lobar or segmental orifice which can be seen directly. From the results of bronchoscopic experiments on anaesthetized dogs it has been found that characteristic patterns of gas concentration changes are observed from regional bronchi during the breathing cycle and that these can be related to the ventilation, blood flow, and mechanical properties of the relevant lobe or segment. In this paper we shall first summarize these results from animal experiments and then present some examples of these characteristic patterns seen during routine diagnostic bronchoscopy in man and discuss their significance.