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Quantifying (12/13)CH(4) migration and fate following sub-surface release to an agricultural soil

Shaw G, Atkinson B, Meredith W, Snape C, Steven M, Hoch A, et al.

J Environ Radioact, 2014 Jul;133:18-23.
PMID: 23958331 DOI: 10.1016/j.jenvrad.2013.07.006

Following gas generation in a Geological Disposal Facility (GDF), (14)C-containing gases could migrate through the geosphere, eventually diffusing into soils at the Earth's surface. This paper reports summary results from laboratory and field experiments to obtain information on the probable rates of a) diffusive transport and b) oxidation of (12/13)CH(4) (as a surrogate for (14)CH4) in a typical agricultural soil in the UK. Rates of CH(4) oxidation were generally low in the field and undisturbed soil columns, though a re-packed column of homogenised topsoil oxidised ambient atmospheric CH(4) 20× faster than an undisturbed soil column. In contrast to low observed rates of CH(4) oxidation, the effective diffusion of CH(4) through the soil was rapid. Isotopically labelled CH(4) injected at a depth of 45 cm in the field diffused to the surface and exited the soil over a time period ranging from 8 to 24 h. The rate of CH(4) diffusion through the soil was increased by the presence of ryegrass roots which increased soil porosity and decreased water content. δ(13)C values for laboratory column soils after labelled CH(4) injection experiments showed no sign of residual (13)C, despite the extremely high δ(13)C values of the injected (12/13)CH(4). If laboratory observations are confirmed by measurements in field samples it can be concluded that the majority of (14)CH(4) from a GDF which enters a soil with low methanotrophic activity will be lost to the free atmosphere after diffusing rapidly through the soil column.
Fulltext Changes in salivary immunoglobulin A (IgA) following match-play and training among English premiership footballers

Fredericks S, Fitzgerald L, Shaw G, Holt DW

Med J Malaysia, 2012 Apr;67(2):155-8.
PMID: 22822634

Decreased salivary immunoglobulin A (sIgA), a component of mucosal immunity, is associated with intensive physical activity: suggesting that sIgA may be used for the monitoring of mucosal immunity with footballers. We investigated changes in sIgA in elite footballers, in response to training and match-play. There was a decrease in sIgA following training, with a return to pre-training levels after 18 hours of rest. This return to resting levels was not observed following competitive match-play. Overnight rest was sufficient for mucosal IgA recovery following training but not following two successive matches, suggesting that sIgA may be used to monitor training in multi-sprint sports.
Effective sample size estimation for a mechanical ventilation trial through Monte-Carlo simulation: Length of mechanical ventilation and Ventilator Free Days

Morton SE, Chiew YS, Pretty C, Moltchanova E, Scarrott C, Redmond D, et al.

Math Biosci, 2017 02;284:21-31.
PMID: 27301378 DOI: 10.1016/j.mbs.2016.06.001

Randomised control trials have sought to seek to improve mechanical ventilation treatment. However, few trials to date have shown clinical significance. It is hypothesised that aside from effective treatment, the outcome metrics and sample sizes of the trial also affect the significance, and thus impact trial design. In this study, a Monte-Carlo simulation method was developed and used to investigate several outcome metrics of ventilation treatment, including 1) length of mechanical ventilation (LoMV); 2) Ventilator Free Days (VFD); and 3) LoMV-28, a combination of the other metrics. As these metrics have highly skewed distributions, it also investigated the impact of imposing clinically relevant exclusion criteria on study power to enable better design for significance. Data from invasively ventilated patients from a single intensive care unit were used in this analysis to demonstrate the method. Use of LoMV as an outcome metric required 160 patients/arm to reach 80% power with a clinically expected intervention difference of 25% LoMV if clinically relevant exclusion criteria were applied to the cohort, but 400 patients/arm if they were not. However, only 130 patients/arm would be required for the same statistical significance at the same intervention difference if VFD was used. A Monte-Carlo simulation approach using local cohort data combined with objective patient selection criteria can yield better design of ventilation studies to desired power and significance, with fewer patients per arm than traditional trial design methods, which in turn reduces patient risk. Outcome metrics, such as VFD, should be used when a difference in mortality is also expected between the two cohorts. Finally, the non-parametric approach taken is readily generalisable to a range of trial types where outcome data is similarly skewed.
Estimating Enhanced Endogenous Glucose Production in Intensive Care Unit Patients with Severe Insulin Resistance

Yahia A, Szlávecz Á, Knopp JL, Norfiza Abdul Razak N, Abu Samah A, Shaw G, et al.

J Diabetes Sci Technol, 2021 Jun 02.
PMID: 34078114 DOI: 10.1177/19322968211018260

BACKGROUND: Critically ill ICU patients frequently experience acute insulin resistance and increased endogenous glucose production, manifesting as stress-induced hyperglycemia and hyperinsulinemia. STAR (Stochastic TARgeted) is a glycemic control protocol, which directly manages inter- and intra- patient variability using model-based insulin sensitivity (SI). The model behind STAR assumes a population constant for endogenous glucose production (EGP), which is not otherwise identifiable.
OBJECTIVE: This study analyses the effect of estimating EGP for ICU patients with very low SI (severe insulin resistance) and its impact on identified, model-based insulin sensitivity identification, modeling accuracy, and model-based glycemic clinical control.
METHODS: Using clinical data from 717 STAR patients in 3 independent cohorts (Hungary, New Zealand, and Malaysia), insulin sensitivity, time of insulin resistance, and EGP values are analyzed. A method is presented to estimate EGP in the presence of non-physiologically low SI. Performance is assessed via model accuracy.
RESULTS: Results show 22%-62% of patients experience 1+ episodes of severe insulin resistance, representing 0.87%-9.00% of hours. Episodes primarily occur in the first 24 h, matching clinical expectations. The Malaysian cohort is most affected. In this subset of hours, constant model-based EGP values can bias identified SI and increase blood glucose (BG) fitting error. Using the EGP estimation method presented in these constrained hours significantly reduced BG fitting errors.
CONCLUSIONS: Patients early in ICU stay may have significantly increased EGP. Increasing modeled EGP in model-based glycemic control can improve control accuracy in these hours. The results provide new insight into the frequency and level of significantly increased EGP in critical illness.
Fulltext Accelerating harm reduction interventions to confront the HIV epidemic in the Western Pacific and Asia: the role of WHO (WPRO)

Mesquita F, Jacka D, Ricard D, Shaw G, Tieru H, Hu Y, et al.

Harm Reduct J, 2008 Aug 05;5:26.
PMID: 18680604 DOI: 10.1186/1477-7517-5-26

The epidemic of HIV/AIDS linked to injecting drug usage is one of the most explosive in recent years. After a historical epicentre in Europe, South and North America, at present it is clearly the main cause of dissemination of the epidemic in Eastern Europe and some key Asian countries. Recently, 10 African countries reported the spread of HIV through people who inject drugs (PWID), breaking one of the final geographical barriers to the globalization of the epidemic of HIV among and from PWID. Several countries of the Asia and Pacific Region have HIV epidemics that are driven by injecting drug usage. Harm reduction interventions have been implemented in many countries and potential barriers to implementation are being overcome. Harm reduction is no longer a marginal approach in the Region; instead, it is the core tool for responding to the HIV/AIDS epidemic among PWID. The development of a comprehensive response in the Region has been remarkable, including scaling up of needle and syringe programmes (NSPs), methadone maintenance treatment (MMT), and care, support and treatment for PWID. This development is being followed up by strong ongoing changes in policies and legislations. The main issue now is to enhance interventions to a level that can impact the epidemic. The World Health Organization (WHO) is one of the leading UN agencies promoting harm reduction. Since the establishment of the Global Programme on AIDS, WHO has been working towards an effective response to the HIV epidemic among PWID. WHO's work is organized into a number of components: establishing an evidence base; advocacy; development of normative standards, tools and guidelines; providing technical support to countries; ensuring access to essential medicines, diagnostics and commodities; and mobilizing resources. In this paper, we trace the course of development of the HIV/AIDS epidemic among and from PWID in the Western Pacific and Asia Region (WPRO) as well as WHO's role in supporting the response in some of the key countries: Cambodia, China, Lao PDR, Malaysia, the Philippines and Viet Nam.