Wave propagation in semiconvective regions of giant planets

Recent observations of Jupiter and Saturn suggest that heavy elements may be diluted in the gaseous envelope, providing a compositional gradient that could stabilise ordinary convection and produce a stably-stratified layer near the core of these planets. This region could consist of semi-convective layers with a staircase-like density profile, which have multiple convective zones separated by thin stably-stratified interfaces, as a result of double-diffusive convection. These layers could have important effects on wave propagation and tidal dissipation that have not been fully explored. We analyse the effects of these layers on the propagation and transmission of internal waves within giant planets, extending prior work in a local Cartesian model. We adopt a simplified global Boussinesq planetary model in which we explore the internal waves in a non-rotating spherical body. We begin by studying the free modes of a region containing semi-convective layers. We then analyse the transmission of internal waves through such a region. The free modes depend strongly on the staircase properties, and consist of modes with both internal and interfacial gravity wave-like behaviour. We determine the frequency shifts of these waves as a function of the number of steps to explore their potential to probe planetary internal structures. We also find that wave transmission is strongly affected by the presence of a staircase. Very large-wavelength waves are transmitted efficiently, but small-scale waves are only transmitted if they are resonant with one of the free modes. The effective size of the core is therefore larger for non-resonant modes

Digital habits of pulmonary rehabilitation service-users following the COVID-19 pandemic

Objective: We previously demonstrated low levels of digital literacy amongst pulmonary rehabilitation service-users prior to the COVID-19 pandemic. We aimed to identify whether the pandemic accelerated digital literacy in this population, resulting in greater acceptance of remote web-based pulmonary rehabilitation programme models. Methods: We surveyed digital access and behaviours and pulmonary rehabilitation delivery preferences of service-users referred to pulmonary rehabilitation in 2021 (cohort 2021) and propensity score-matched them to a cohort who completed the survey in 2020 (cohort 2020). Results: There were indicators that digital access and confidence were better amongst the Cohort 2021 but no difference was seen in the proportion of patients choosing remote web-based pulmonary rehabilitation as an acceptable method of receiving pulmonary rehabilitation. Conclusion: In an unselected cohort of service-users, remote web-based pulmonary rehabilitation was considered acceptable in only a minority of patients which has implications on healthcare commissioning and delivery of pulmonary rehabilitation

Neonatal desensitisation for the study of regenerative medicine

Cell replacement is a therapeutic option for numerous diseases of the CNS. Current research has identified a number of potential human donor cell types, for which preclinical testing through xenotransplantation in animal models is imperative. Immune modulation is necessary to promote donor cell survival for sufficient time to assess safety and efficacy. Neonatal desensitization can promote survival of human donor cells in adult rat hosts with little impact on the health of the host and for substantially longer than conventional methods, and has subsequently been applied in a range of studies with variable outcomes. Reviewing these findings may provide insight into the method and its potential for use in preclinical studies in regenerative medicine

Microbial dynamics in a High Arctic glacier forefield: A combined field, laboratory, and modelling approach

Modelling the development of soils in glacier forefields is necessary in order to assess how microbial and geochemical processes interact and shape soil development in response to glacier retreat. Furthermore, such models can help us predict microbial growth and the fate of Arctic soils in an increasingly ice-free future. Here, for the first time, we combined field sampling with laboratory analyses and numerical modelling to investigate microbial community dynamics in oligotrophic proglacial soils in Svalbard. We measured low bacterial growth rates and growth efficiencies (relative to estimates from Alpine glacier forefields) and high sensitivity of bacterial growth rates to soil temperature (relative to temperate soils). We used these laboratory measurements to inform parameter values in a new numerical model and significantly refined predictions of microbial and biogeochemical dynamics of soil development over a period of roughly 120 years. The model predicted the observed accumulation of autotrophic and heterotrophic biomass. Genomic data indicated that initial microbial communities were dominated by bacteria derived from the glacial environment, whereas older soils hosted a mixed community of autotrophic and heterotrophic bacteria. This finding was simulated by the numerical model, which showed that active microbial communities play key roles in fixing and recycling carbon and nutrients. We also demonstrated the role of allochthonous carbon and microbial necromass in sustaining a pool of organic material, despite high heterotrophic activity in older soils. This combined field, laboratory, and modelling approach demonstrates the value of integrated model-data studies to understand and quantify the functioning of the microbial community in an emerging High Arctic soil ecosystem

Pulmonary rehabilitation in idiopathic pulmonary fibrosis and COPD: a propensity matched real-world study

BACKGROUND: The adherence to and clinical efficacy of pulmonary rehabilitation in idiopathic pulmonary fibrosis (IPF), particularly in comparison to people with chronic obstructive pulmonary disease (COPD), remains uncertain. The objectives of this real-world study were to compare the responses of patients with IPF with a matched group of patients with COPD undergoing the same supervised, outpatient pulmonary rehabilitation program, and to determine whether pulmonary rehabilitation is associated with survival in IPF. RESEARCH QUESTION: Do people with IPF improve to the same extent with pulmonary rehabilitation as a matched group of individuals with COPD, and are non-completion of and/or non-response to pulmonary rehabilitation associated with one-year all-cause mortality in IPF? STUDY DESIGN AND METHODS: Using propensity score matching, 163 patients with IPF were matched 1:1 with a control group of 163 patients with COPD referred to pulmonary rehabilitation. We compared between-group pulmonary rehabilitation completion rates and response. Survival status in the IPF cohort was recorded over one-year following pulmonary rehabilitation discharge. Cox proportional-hazards regression explored the association between pulmonary rehabilitation status and all-cause mortality. RESULTS: Similar pulmonary rehabilitation completion rates (IPF: 69%; COPD: 63%; p=0.24) and improvements in exercise response were observed in both groups with no significant mean (95% confidence interval (CI)) between-group differences in incremental shuttle walk (ISW) change (2 (-18 to 22) meters). Pulmonary rehabilitation non-completion (hazard ratio (HR) (95%CI) 5.62 (2.24 to 14.08)) and non-response (HR (95%CI) 3.91 (1.54 to 9.93)) were independently associated with increased one-year all-cause mortality in IPF. INTERPRETATION: Compared with a matched group of patients with COPD, this real-word study demonstrates that patients with IPF have similar completion rates and magnitude of response to pulmonary rehabilitation. In IPF, non-completion of and non-response to pulmonary rehabilitation were associated with increased all-cause mortality. These data reinforce the benefits of pulmonary rehabilitation in patients with IPF

The influence of age and sex on cerebrovascular reactivity and ventilatory response to hypercapnia in children and adults

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordThe purpose of this study was to compare the integrated intracranial cerebrovascular reactivity (CVR) and hypercapnic ventilatory response (HCVR) between children and adults, as well as explore the dynamic response of the middle cerebral artery mean velocity (MCAV). Children (n = 20; 9.9 ± 0.7 years) and adults (n = 21; 24.4 ± 2.0 years) completed assessment of CVR over 240s using a fixed concentration of inspired CO2 (FICO2, 0.06). Baseline MCAV was higher in the adult females compared to the males (p ≤ .05). MCAV was greater in female children compared to male children (p ≤ .05), and in female adults compared to male adults (p ≤ .05) with hypercapnia. Relative CVR was similar in children and adults (3.71 ± 1.06 vs. 4.12 ± 1.32 %/mmHg; p = .098), with absolute CVR higher in adult females than males (3.27 ± .86 vs. 2.53 ± .70 cm/s/mmHg; p ≤ . 001). Likewise, HCVR did not differ between the children and adults (1.89 ± 1.00 vs. 1.77 ± 1.34 L/min/mmHg; p = .597), but was lower in adult females than males (1.815 ± 37 vs. 2.33 ± 1.66 L/min/mmHg; p ≤ .05). The heart rate response to hypercapnia was greater in children than adults (p = 001). A mono‐exponential regression model was used to characterize the dynamic onset, consisting of a delay term, amplitude and time constant (τ). The results revealed that MCAV τ was faster in adults than in children (34 ± 18 vs .74 ± 28 s; p = .001). Our study provides new insight into the impact of age and sex on CVR and the dynamic response of the MCAV to hypercapnia.Natural Sciences and Engineering Research CouncilCanadian Foundation for Innovatio

The minimum clinically important difference of the incremental shuttle walk test in bronchiectasis: a prospective cohort study.

The incremental shuttle walk test (ISW) is an externally-paced field walking test that measures maximal exercise capacity1 and is widely used in patients with chronic obstructive pulmonary disease (COPD) undergoing pulmonary rehabilitation (PR). Its psychometric properties, including reliability, construct validity2 and responsiveness to intervention,2-5 have been demonstrated in patients with bronchiectasis, but little data exist on the minimum clinically important difference (MCID). Although two studies have investigated the MCID of ISW in patients with bronchiectasis, the generalisability of these data is limited because of the study sample characteristics,6 or did not involve an exercise-based intervention.2 The MCID enables clinicians and researchers to understand the clinical significance of change data and forms an important part of the evidence required by regulatory agencies for approval for use in clinical trials. Accordingly, the aim of this study was to provide MCID estimates of the ISW in response to intervention, namely PR, in patients with bronchiectasis

Birthweight and risk markers for type 2 diabetes and cardiovascular disease in childhood: the Child Heart and Health Study in England (CHASE).

AIMS/HYPOTHESIS: Lower birthweight (a marker of fetal undernutrition) is associated with higher risks of type 2 diabetes and cardiovascular disease (CVD) and could explain ethnic differences in these diseases. We examined associations between birthweight and risk markers for diabetes and CVD in UK-resident white European, South Asian and black African-Caribbean children. METHODS: In a cross-sectional study of risk markers for diabetes and CVD in 9- to 10-year-old children of different ethnic origins, birthweight was obtained from health records and/or parental recall. Associations between birthweight and risk markers were estimated using multilevel linear regression to account for clustering in children from the same school. RESULTS: Key data were available for 3,744 (66%) singleton study participants. In analyses adjusted for age, sex and ethnicity, birthweight was inversely associated with serum urate and positively associated with systolic BP. After additional height adjustment, lower birthweight (per 100 g) was associated with higher serum urate (0.52%; 95% CI 0.38, 0.66), fasting serum insulin (0.41%; 95% CI 0.08, 0.74), HbA1c (0.04%; 95% CI 0.00, 0.08), plasma glucose (0.06%; 95% CI 0.02, 0.10) and serum triacylglycerol (0.30%; 95% CI 0.09, 0.51) but not with BP or blood cholesterol. Birthweight was lower among children of South Asian (231 g lower; 95% CI 183, 280) and black African-Caribbean origin (81 g lower; 95% CI 30, 132). However, adjustment for birthweight had no effect on ethnic differences in risk markers. CONCLUSIONS/INTERPRETATION: Birthweight was inversely associated with urate and with insulin and glycaemia after adjustment for current height. Lower birthweight does not appear to explain emerging ethnic difference in risk markers for diabetes

Change in gait speed and adverse outcomes in patients with idiopathic pulmonary fibrosis: a prospective cohort study.

BACKGROUND AND OBJECTIVE: Gait speed is associated with survival in individuals with idiopathic pulmonary fibrosis (IPF). The extent to which four-metre gait speed (4MGS) decline predicts adverse outcome in IPF remains unclear. We aimed to examine longitudinal 4MGS change and identify a cut-point associated with adverse outcome. METHODS: In a prospective cohort study, we recruited 132 individuals newly diagnosed with IPF and measured 4MGS change over 6 months. Death/first hospitalization at 6 months were composite outcome events. Complete data (paired 4MGS plus index event) were available in 85 participants; missing 4MGS data were addressed using multiple imputation. Receiver-Operating Curve plots identified a 4MGS change cut-point. Cox proportional-hazard regression assessed the relationship between 4MGS change and time to event. RESULTS: 4MGS declined over 6 months (mean [95% CI] change: -0.05 [-0.09 to -0.01] m/s; p = 0.02). A decline of 0.07 m/s or more in 4MGS over 6 months had better discrimination for the index event than change in 6-minute walk distance, forced vital capacity, Composite Physiologic Index or Gender Age Physiology index. Kaplan-Meier curves demonstrated a significant difference in time to event between 4MGS groups (substantial decline: >-0.07 m/s versus minor decline/improvers: ≤-0.07 m/s; p = 0.007). Those with substantial decline had an increased risk of hospitalization/death (adjusted hazard ratio [95% CI] 4.61 [1.23-15.83]). Similar results were observed in multiple imputation analysis. CONCLUSION: In newly diagnosed IPF, a substantial 4MGS decline over 6 months is associated with shorter time to hospitalization/death at 6 months. 4MGS change has potential as a surrogate endpoint for interventions aimed at modifying hospitalization/death