An application of semigroup theory to a fragmentation equation

The process of fragmentation arises in many physical situations, including polymer degradation, droplet breakage and rock crushing and grinding. Under suitable assumptions, the evolution of the size distribution c(x, t), where x represents particle size and t is time, may be described by the linear integro-differential equation

Population structure and the burden of disease in the United Arab Emirates

AbstractTo carry out their duties more effectively, health care professionals in the UAE often ask about the population structure and the main causes of mortality and morbidity in the country. This paper summarizes what is known about these topics drawing on secondary data sources that are available in the public domain, including census data, population estimates, births and deaths, proportionate mortality, age-standardized mortality rates and disability adjusted life-years. There are inconsistencies and flaws in some of this data which this paper will highlight and attempt to explain. Since 2005, the UAE population has grown substantially owing to high natural growth and high net inward migration and is currently estimated to be about 8.2million. In 2008, injuries, heart disease, neoplasms and cerebrovascular disease accounted for 57% of deaths, and this is well known. Less is reported about the risk of death, disease, injury and disability. The population of the UAE is diverse, and there are variations in mortality and morbidity risk by age-group, sex and nationality. The authors recommend improvements in the timeliness, completeness and consistency of data. They conclude that better data will encourage more analysis which will generate health intelligence leading to health improvement for the UAE population

Dynamic Boolean modelling reveals the influence of energy supply on bacterial efflux pump expression

Antimicrobial resistance (AMR) is a global health issue. One key factor contributing to AMR is the ability of bacteria to export drugs through efflux pumps, which relies on the ATP-dependent expression and interaction of several controlling genes. Recent studies have shown that significant cell-to-cell ATP variability exists within clonal bacterial populations, but the contribution of intrinsic cell-to-cell ATP heterogeneity is generally overlooked in understanding efflux pumps. Here, we consider how ATP variability influences gene regulatory networks controlling expression of efflux pump genes in two bacterial species. We develop and apply a generalizable Boolean modelling framework, developed to incorporate the dependence of gene expression dynamics on available cellular energy supply. Theoretical results show that differences in energy availability can cause pronounced downstream heterogeneity in efflux gene expression. Cells with higher energy availability have a superior response to stressors. Furthermore, in the absence of stress, model bacteria develop heterogeneous pulses of efflux pump gene expression which contribute to a sustained sub-population of cells with increased efflux expression activity, potentially conferring a continuous pool of intrinsically resistant bacteria. This modelling approach thus reveals an important source of heterogeneity in cell responses to antimicrobials and sheds light on potentially targetable aspects of efflux pump-related antimicrobial resistance.publishedVersio

Structural investigation and compression of a co-crystal of indomethacin and saccharin

The co-crystalline structure of the non-steroidal, anti-inflammatory indomethacin with the non-toxic, Generally Regarded As Safe (GRAS) sweetener component saccharin was investigated up to 6.33 GPa using a Diamond Anvil Cell (DAC). Single crystal X-ray diffraction measurements show that the co-crystal remains in the same triclinic, P-1, phase throughout the compression with a significant reduction in void space (155.69 to 55.61Å3). Information on the response of different types of intermolecular interactions to external force at the same time is enabled by the use of a co-crystal. We have rationalised that the length and compression rate of the saccharin amide dimer in the co-crystal is caused by the dimer sitting in a ‘pocket’ surrounded by the indomethacin framework. This framework reduces the effects of molecular packing on the dimer allowing for an ideal hydrogen bonding geometry

Cigarette smoking and smokeless tobacco use among male south Asian migrants in the United Arab Emirates: A cross-sectional study

Background: Few data were available on smoking and smokeless tobacco use in South Asian migrants in the United Arab Emirates (UAE). This study aimed to identify the prevalence and correlates of cigarette smoking and smokeless tobacco use in male South Asian migrants in the UAE.Methods: We used a cross-sectional study to recruit a random representative sample of male South Asian migrants, including Indian (n = 433), Pakistani (n = 383) and Bangladeshi (n = 559) nationalities. We used multivariable logistic regression analysis to identify significant correlates of cigarettes smoking and smokeless tobacco use.Results: 1375 South Asian migrant adult males participated in the study (response rate 76%) with a mean age of 34 years (SD ± 10). The overall prevalence of cigarette smoking was 28% (95%CI 25-30%) and smokeless tobacco use was 11% (95%CI 10-13%). The prevalence of current cigarette smoking was 21, 23, and 37% among participants from India, Pakistan and Bangladesh, respectively. The prevalence of current smokeless tobacco use was 6, 12, and 16% for Indian, Pakistani, and Bangladeshi participants, respectively. Among study participants, Bangladeshi nationality, hypertension, and alcohol use were significant correlates of current cigarette smoking. Significant correlates of smokeless tobacco use included increased age, less than college level education, alcohol use, and Pakistani or Bangladeshi nationality.Conclusions: Current smoking and smokeless tobacco use in South Asian migrants represent a significant public health burden in the UAE. Effective public health measures are needed to reduce tobacco use in this migrant population

REFERQUAL: A pilot study of a new service quality assessment instrument in the GP Exercise Referral scheme setting

Background The development of an instrument accurately assessing service quality in the GP Exercise Referral Scheme (ERS) industry could potentially inform scheme organisers of the factors that affect adherence rates leading to the implementation of strategic interventions aimed at reducing client drop-out. Methods A modified version of the SERVQUAL instrument was designed for use in the ERS setting and subsequently piloted amongst 27 ERS clients. Results Test re-test correlations were calculated via Pearson's 'r' or Spearman's 'rho', depending on whether the variables were Normally Distributed, to show a significant (mean r = 0.957, SD = 0.02, p < 0.05; mean rho = 0.934, SD = 0.03, p < 0.05) relationship between all items within the questionnaire. In addition, satisfactory internal consistency was demonstrated via Cronbach's 'α'. Furthermore, clients responded favourably towards the usability, wording and applicability of the instrument's items. Conclusion REFERQUAL is considered to represent promise as a suitable tool for future evaluation of service quality within the ERS community. Future research should further assess the validity and reliability of this instrument through the use of a confirmatory factor analysis to scrutinise the proposed dimensional structure