Two-step hybrid calibration of remote microphones.

A two-step, hybrid procedure to calibrate the remote microphones is presented. The calibration obtained in this manner can be directly applied to the measured pressure spectrum without resorting to any modeling or assumptions about the shape of the calibration curve. To demonstrate an application of the methodology, measurements of wall pressure fluctuations underneath a zero pressure gradient turbulent boundary layer were made. The calibrated pressure spectrum is shown to be qualitatively and quantitatively consistent with previous experimental studies and an empirical model, indicating the accuracy of the hybrid calibration technique.

An experimental application of aeroacoustic time-reversal to the Aeolian tone.

This paper presents an experimental application of the aeroacoustic time-reversal (TR) source localization technique for studying flow-induced noise problems and compares the TR results with those obtained using conventional beamforming (CB). Experiments were conducted in an anechoic wind tunnel for the benchmark test-case of a full-span circular cylinder located in subsonic cross-flow wherein the far-field acoustic pressure was sampled using two line arrays (LAs) of microphones located above and below the cylinder. The source map obtained using the signals recorded at the two LAs without modeling the reflective surfaces of the contraction-outlet and cylinder during TR simulations revealed the lift-dipole nature of aeroacoustic source generated at the Aeolian tone; however, it indicates an error of 3/20 of Aeolian tone wavelength in the predicted location. Modeling the reflective contraction-outlet during TR was shown to improve the focal-resolution of the source and reduce side-lobe levels, especially in the low-frequency range. The experimental TR results were shown to be comparable to (a) the simulation results of an idealized dipole at the cylinder location in wind-tunnel flow and (b) that obtained by monopole and dipole CB, thereby demonstrating the suitability of TR method as a diagnostic tool to analyze flow-induced noise generation mechanism.

Enhancing the focal-resolution of aeroacoustic time-reversal using a point sponge-layer damping technique.

This letter presents the Point-Time-Reversal-Sponge-Layer (PTRSL) technique to enhance the focal-resolution of aeroacoustic Time-Reversal (TR). A PTRSL is implemented on a square domain centered at the predicted source location and is based on damping the radial components of the incoming and outgoing fluxes propagating toward and away from the source, respectively. A PTRSL is shown to overcome the conventional half-wavelength diffraction-limit; its implementation significantly reduces the focal spot size to one-fifth of a wavelength for a monopole source. Furthermore, PTRSL reduces the focal spots of a dipole source to three-tenths of a wavelength, as compared to three-fifths without its implementation.

Multiple line arrays for the characterization of aeroacoustic sources using a time-reversal method.

This letter investigates the use of multiple line arrays (LAs) in a Time-Reversal Mirror for localizing and characterizing multipole aeroacoustic sources in a uniform subsonic mean flow using a numerical Time-Reversal (TR) method. Regardless of the original source characteristics, accuracy of predicting the source location can be significantly improved using at least two LAs. Furthermore, it is impossible to determine the source characteristics using a single LA, rather a minimum of two are required to establish either the monopole or dipole source nature, while four LAs (fully surrounding the source) are required for characterizing a lateral quadrupole source.

An evaluation of the experiences of academics and practice educators who supported radiography students working on the temporary HCPC register during the COVID-19 pandemic.

INTRODUCTION: The COVID-19 pandemic has had a profound impact on all those residing in the United Kingdom, resulting in unprecedented changes being made to the education and training of healthcare students. Universities and practice partners had to respond quickly and work in close collaboration with Health Education England, to ensure the changes brought in by the Health and Care Professions Council (HCPC) emergency measures were implemented. The aim of this study was to explore the experiences of staff supporting final year diagnostic and therapeutic radiography students who joined the HCPC register early during phase one of the COVID-19 pandemic. METHODS: This study was informed by a phenomenological approach, in which a purposeful sample of eight participants comprising of six practice educators (PEs) and two academics. Semi-structured interviews and focus groups were conducted to collect the data via a virtual platform. RESULTS: The results highlighted three themes, Competence and the transition to registration, Support mechanisms and Communication. Both academics and PEs described how they observed the new registrants gaining confidence and competence during their time on the temporary register and suggested that professional bodies could consider curriculum changes to encompass a final transitional placement similar to their experience. They suggested that having robust support mechanisms and communication in place are essential for the success of this initiative. CONCLUSION: The results provide insight into how PEs and academics supported new registrants to meet the necessary requirements of the HCPC register whilst working during the first phase of the COVID-19 pandemic. They highlight the importance of having robust support mechanisms and good communication in place to achieve this. IMPLICATIONS FOR PRACTICE: Some consideration could be made to changing the curriculum in the future to allow for early temporary registration and paid Band 4 final placements for students working as assistant practitioners.

An evaluation of the experiences of radiography students working on the temporary HCPC register during the COVID-19 pandemic.

INTRODUCTION: The COVID-19 pandemic has changed the world's perspective and had a profound impact on all those residing in the United Kingdom, resulting in unprecedented changes being made to the education and training of healthcare students. Universities and practice partners had to respond quickly and work in close collaboration with their wider system partners, Health Education England and the Department of Health, to ensure the changes made within the Health and Care Professions Council (HCPC) emergency measures were implemented. The aim was to explore the experiences of final year diagnostic and therapeutic radiography students who joined the HCPC temporary register during phase one of the COVID-19 pandemic. METHODS: This study was informed by a phenomenological approach, in which a purposeful sample of seventeen participants comprising of nine students, six practice educators and two academics were chosen to participate. Semi-structured interviews and focus groups were conducted to collect the data via a virtual platform. RESULTS: The results highlighted three themes, professionalism and transition to registration, benefits and challenges of working through a pandemic, and emotional impact. Students described how they gained confidence and competence during their time on the temporary register and suggested that professional bodies could consider curriculum changes to encompass a final transitional placement similar to their experience. They said they had been well supported but felt a sense of loss having been denied the normal rite of passage associated with completion of their course and graduation. CONCLUSION: The results provide insight into how students, practice educators and academics transformed their practice to meet the necessary requirements whilst working during the first phase of the COVID-19 pandemic. They highlight the importance of having good support mechanisms in place and the rewards and challenges for students joining their professional register early. IMPLICATIONS FOR PRACTICE: Some consideration could be made to changing the curriculum in the future to allow for early temporary registration and paid Band 4 final placements for students working as assistant practitioners.

Impact of isolation precautions on quality of life: a meta-analysis.

Impact of isolation precautions on psychological wellbeing of patients has yet to be fully quantified. To assess the impact of isolation precautions on patients' health-related quality of life and depression or anxiety scales and estimate per day cost of anxiety and depression. Literature pertaining to impact of isolation precautions was searched on EMBASE and PubMed databases and Google Scholar. A two-step independent screening of the articles was performed. Articles that compared isolated and non-isolated patients using different quality of life and psychological burden scales were included. A meta-analysis was conducted using the Hospital Anxiety and Depression Scales (HADS-A and HADS-D). Psychological burden measures from selected literature were presented in a graph as effect sizes. Per day cost of anxiety and depression was estimated using pooled mean difference from meta-analysis. Out of 106 articles, 94 were excluded due to inclusion criteria, leaving 12 for full text review. After review of full text of the articles, seven articles were shortlisted for empirical analysis and four out of these seven for meta-analysis. The pooled mean difference estimates for HADS-A was -1.4 (P=0.15) and that for HADS-D was -1.85 (P=0.09). In the empirical analysis of psychological burden scales, the effect in all studies except one was negative. Results from meta-analysis and empirical analysis of psychological burden implied that isolated patients are worse off in general. The implied estimated per day cost of anxiety and depression in terms of quality-adjusted life years (QALYs) is approximately US$10.

Inhibition by fatty acids of cyclic AMP-dependent protein kinase activity in brush border membranes isolated from human placental vesicles.

1. The inhibitory effects of arachidonic acid (AA) and a number of structurally related fatty acids on cyclic AMP-dependent protein kinase activity have been investigated in brush border membranes (BBM) prepared from human placental vesicles. 2. BBM vesicles were characterized by electron microscopy and displayed enrichment of the appropriate marker enzymes, alkaline phosphatase and gamma-glutamyltranspeptidase; BBM were prepared by vesicles lysis in hypotonic medium. 3. Cyclic AMP-dependent protein kinase (PKA) activity was measured in BBM. At 1 microM, cyclic AMP stimulated a 4.2 +/- 0.06 fold increase over basal levels of [32P]-phosphate incorporation into the synthetic substrate kemptide and this effect was abolished by a selective PKA inhibitor. By use of synergistic pairs of site-selective cyclic AMP analogues, the kinase was identified as the type II enzyme. 4. Cyclic AMP-stimulated PKA activity was inhibited by 10 microM AA and this effect was significantly enhanced by nordihydroguaiaretic acid (NDGA) + indomethacin (Indo), inhibitors of the lipoxygenase and cyclo-oxygenase pathways of AA metabolism respectively. 5. Oleic acid, elaidic acid, but not caprylic or palmitic acids, also significantly inhibited PKA activity and this effect was again enhanced by NDGA + Indo. While arachidonyl alcohol alone was not inhibitory, in the presence of the metabolic inhibitors a significant reduction in stimulated activity was observed. 6. The commercially available PKA type II holoenzyme (activated by cyclic AMP), but not the free catalytic subunit, was inhibitable by AA, oleic or elaidic acids. 7. These results suggest that PKA localized to the brush border membrane of human placental vesicles is inhibited by fatty acids which may compete with cyclic AMP for binding to the kinase regulatory subunit. The reported inhibition by fatty acids of cyclic AMP-dependent Cl- secretion in epithelial cells may therefore be due in part to negative regulation of a Cl- channel-associated PKA.

Rapid non-genomic activation of cytosolic cyclic AMP-dependent protein kinase activity and [Ca(2+)](i) by 17beta-oestradiol in female rat distal colon.

1. In this study, the effect of 17beta-oestradiol on adenosine 3' : 5'-cyclic monophosphate (cyclic AMP)-dependent protein kinase (PKA) activity was investigated. 2. Rapid (within 15 min) activation of basal PKA activity was observed in cytosolic fractions by 17beta-oestradiol but not by 17alpha-oestradiol, progesterone or testosterone. This stimulation was abolished by the specific PKA inhibitor PKI but not by the classical oestrogen receptor antagonist tamoxifen. 3. 17beta-Oestradiol did not stimulate basal PKA activity in membrane fractions or in cytosolic fractions from male rats. 4. The increase in cytosolic PKA activity was indirect as (i) it was inhibited by the adenylyl cyclase inhibitor SQ22536, (ii) it was mimicked by forskolin and (iii) 17beta-oestradiol did not cause a stimulation of basal PKA activity in either type I or type II commercially available PKA holoenzymes. 5. Protein kinase Cdelta (PKCdelta) was directly activated by 17beta-oestradiol. The specific PKC inhibitor, bisindolylmaleimide I (GF 109203X), abolished the 6. 17beta-oestradiol-induced PKA activation. 17beta-Oestradiol stimulate an increase in free intracellular calcium ion concentration ([Ca(2+)](i)) in isolated female but not male rat colonic crypts. This was inhibited by verapamil, nifedipine and zero extracellular [Ca(2+)] but unaffected by tamoxifen. 17alpha-Oestradiol, testosterone and progesterone failed to increase [Ca(2+)](i). 7. PKC and PKA inhibitors abolished the 17beta-oestradiol-induced increase in [Ca(2+)](i). 8. These results demonstrate the existence of a novel 17beta-oestradiol-specific PKA and Ca(2+) signalling pathway, which is both sex steroid- and gender-specific, in rat distal colonic epithelium.

Rapid effects of corticosteroids on cytosolic protein kinase C and intracellular calcium concentration in human distal colon.

Recent studies from our laboratory have reported rapid (< 1 min) non-genomic activation of potassium recycling, Na+-H+ exchange, protein kinase C (PKC) activity and PKC-sensitive Ca2+ entry by mineralocorticoids in mammalian distal colonic epithelium. Previous studies from other laboratories have described stimulation of the Na+-H+ exchanger by PKC activation. Here a rapid non-genomic effect of aldosterone on PKC activity and intracellular free calcium [Ca2+]i is demonstrated in human distal colonic epithelium. Rapid activation (after 15 min incubation) of basal PKC activity was observed in cytosolic fractions of human colonic epithelium by aldosterone, fludrocortisone and deoxycorticosterone acetate (DOCA). PKC activation was inhibited by the specific PKC inhibitor bisindolylmaleimide (GF109203X). The glucocorticoid hydrocortisone failed to activate PKC activity. Aldosterone induced a rapid increase in [Ca2+]i in isolated human colonic crypts. This stimulatory effect on [Ca2+]i was inhibited by the PKC inhibitor chelerythrine chloride. Hydrocortisone and dexamethasone similarly failed to increase [Ca2+]i. These results indicate that intracellular signalling for aldosterone involves changes in [Ca2+]i via activation of PKC. Since stimulation of PKC activity and increase in [Ca2+]i are apparent at normal circulating levels of aldosterone, our findings may have important physiological implications and prompt a reassessment of mineralocorticoid effects on electrolyte homeostasis.

Rapid responses to aldosterone in human distal colon.

Aldosterone at normal physiological levels induces rapid increases in intracellular calcium and pH in human distal colon. The end target of these rapid signaling responses are basolateral K+ channels. Using spectrofluorescence microscopy and Ussing chamber techniques, we have shown that aldosterone activates basolateral Na/H exchange via a protein kinase C and calcium-dependent signaling pathway. The resultant intracellular alkalinization up-regulates an adenosine triphosphate (ATP)-dependent K+ channel (K(ATP)) and inhibits a Ca2+ -dependent K+ channel (K(Ca)). In Ussing chamber experiments, we have shown that the K(ATP) channel is required to drive sodium absorption, whereas the K(Ca) channel is necessary for both cyclic adenosine monophosphate and calcium-dependent chloride secretion. The rapid effects of aldosterone on intracellular calcium, pH, protein kinase C and K(ATP), K(Ca) channels are insensitive to cycloheximide, actinomycin D, and spironalactone, indicating a nongenomic mechanism of action. We propose that the physiological role for the rapid nongenomic effect of aldosterone is to prime pluripotential epithelia for absorption by simultaneously up-regulating K(ATP) channels to drive absorption through surface cells and down-regulating the secretory capacity by inhibiting K(Ca) channels involved in secretion through crypt cells.

Rapid effects of steroid hormones on free intracellular calcium in T84 colonic epithelial cells.

Studies from our laboratory have demonstrated rapid (< 1 min) nongenomic activation of K+ recycling and Na+/H+ exchange by mineralocorticoids in human colonic epithelium, and studies from other laboratories have demonstrated rapid effects of aldosterone on intracellular Ca2+ concentration ([Ca2+]i) in endothelial cells. Here a rapid nongenomic effect of aldosterone on [Ca2+]i is demonstrated in the human colonic epithelial cell line T84. Aldosterone induced a rapid increase in [Ca2+]i within approximately 2 min. The rise in [Ca2+]i after aldosterone appears to result from the activation of a Ca2+ influx pathway, inasmuch as 1) no increase in [Ca2+]i was observed with aldosterone when cells were bathed in Ca(2+)-free Krebs solution and 2) emptying of the intracellular Ca2+ stores by thapsigargin was not enhanced by addition of aldosterone to extracellular Ca(2+)-free solution. In contrast, the Ca2+ response to aldosterone, in the presence of 2 mM Ca2+ in the external bathing solution, was not decreased after intracellular Ca2+ stores were emptied by thapsigargin. Other mineralocorticoid hormones increased [Ca2+]i, whereas the glucocorticoid hydrocortisone failed to increase [Ca2+]i. These results demonstrate the existence of a mineralocorticoid-specific Ca(2+)-signaling pathway in human colonic T84 (crypt) epithelial cells.

Modulation of cytosolic protein kinase C and calcium ion activity by steroid hormones in rat distal colon.

Studies from our laboratory have demonstrated rapid (<1 min) non-genomic activation of Na+-H+ exchange and potassium recycling by mineralocorticoids in human and rat colonic epithelium. It has previously been demonstrated that Na+-H+ exchange may be stimulated by protein kinase C (PKC) activation; therefore, we examined the effect of mineralocorticoids on PKC activity in rat colonic epithelium. Activation (after 15 min of incubation) of basal PKC activity was observed in cytosolic fractions of rat colonic epithelium by aldosterone, fludrocortisone, and deoxycorticosterone acetate. In all instances, PKC activation was inhibited by the PKC inhibitor bisindolylmaleimide (GF109203X). Hydrocortisone failed to activate PKC activity. Stimulation of basal intracellular free calcium [Ca2+]i was observed, in isolated rat colonic crypts, following aldosterone addition. This stimulatory effect was inhibited by the PKC inhibitor, chelerythrine chloride. Hydrocortisone failed to increase [Ca2+]i. These results indicate that intracellular signaling for aldosterone involves changes in [Ca2+]i via activation of PKC. Since the stimulation of PKC and increase in [Ca2+]i are apparent at normal circulating levels of aldosterone, our findings have major implications for the reassessment of mineralocorticoid effects on electrolyte homeostasis.

17beta-oestradiol acutely regulates Cl- secretion in rat distal colonic epithelium.

In this study we used the short circuit current (ISC) technique to measure the non-genomic effects of the female sex steroid 17beta-oestradiol (E2) on electrogenic transepithelial ion transport in rat distal colonic epithelium. Basal ISC was largely composed of a transepithelial Cl- secretory component with minimal electrogenic Na+ movement. E2 (1-100 nM) caused a significant decrease in basal ISC after 15 min. In addition, pre-treating colonic epithelial tissues with E2 (0.1-100 nM) for 10 min significantly reduced forskolin (20 microM)-induced Cl- secretion. E2 also down-regulated Cl- secretion which was pre-stimulated by forskolin. Cl- secretory responses to the Ca2+-dependent secretagogue carbachol (10 microM) were also significantly reduced in the presence of E2 (10- 100 nM). However, E2 had no effect on amiloride-sensitive Na+ absorption. The rapid anti-secretory effect of E2 was abolished in the presence of the intracellular Ca2+ chelator BAPTA (50 microM) or the protein kinase C (PKC) inhibitor chelerythrine chloride (1 microM). However, in the presence of the nuclear oestrogen receptor antagonist tamoxifen (10 microM), E2 still produced an inhibition of Cl- secretion. Testosterone, progesterone and 17alpha-oestradiol had no significant effect on colonic Cl- secretion. Also, E2 (100 nM) did not alter Cl- secretion in colonic epithelia isolated from male rats. We conclude that E2 inhibits colonic Cl- secretion via a non-genomic pathway that involves intracellular Ca2+ and PKC. It is possible that this gender-specific mechanism contributes to the salt and water retention associated with high E2 states.

Sex and salt hormones: rapid effects in epithelia.

Recent evidence points to protein kinase C isoforms as highly specific receptors for aldosterone and estradiol in epithelia. The end targets of the kinase activation are Na(+)/H(+) exchange and K(+) and Ca(2+) channels. The physiological role of the nongenomic response is to increase electrolyte absorption and inhibit secretion in pluripotential epithelia.

Childhood immunisation: factors associated with failure to complete the recommended schedule by two years of age.

This study aimed to determine the immunisation status of preschool-aged children attending formal child-care facilities in north Queensland, and to examine factors associated with failure to be completely immunised by two years of age. Child-care centres and kindergartens within the Cairns City and Mulgrave Shire local government boundaries were selected randomly with probability proportional to size, and 613 children (median age of 47.0 months) were selected randomly from the facilities. Only 60.3 per cent (95 per cent confidence interval (CI) 56.3 to 64.3) of the children were fully immunised by two years of age. Children who had not received any vaccines by three months of age (that is, 'late starters') were less likely to be fully up-to-date at two years of age than children who started on time (odds ratio (OR) 10.3; CI 5.2 to 20.9). Children without a parent-held immunisation record were less likely to be up-to-date at two years of age than those children with a parent-held immunisation record (OR 2.8; CI 1.9 to 4.0). With follow-up of late-starters, and with the simultaneous administration of overdue vaccines with vaccines given in the second year of life, the percentage of children up-to-date at 24 months of age could have increased from 60.3 per cent to 82.3 per cent (CI 79.1 to 85.5). The immunisation coverage rates were inadequate to prevent outbreaks of vaccine-preventable diseases. Innovative strategies will be required if the vaccine coverage rates are to be improved. The parent-held immunisation record is of fundamental importance to all these strategies.