An investigation of factors associated with the health and well-being of HIV-infected or HIV-affected older people in rural South Africa

BackgroundDespite the severe impact of HIV in sub-Saharan Africa, the health of older people aged 50+ is often overlooked owing to the dearth of data on the direct and indirect effects of HIV on older people's health status and well-being. The aim of this study was to examine correlates of health and well-being of HIV-infected older people relative to HIV-affected people in rural South Africa, defined as participants with an HIV-infected or death of an adult child due to HIV-related cause. MethodsData were collected within the Africa Centre surveillance area using instruments adapted from the World Health Organization (WHO) Study on global AGEing and adult health (SAGE). A stratified random sample of 422 people aged 50+ participated. We compared the health correlates of HIV-infected to HIV-affected participants using ordered logistic regressions. Health status was measured using three instruments: disability index, quality of life and composite health score. ResultsMedian age of the sample was 60 years (range 50-94). Women HIV-infected (aOR 0.15, 95% confidence interval (CI) 0.08-0.29) and HIV-affected (aOR 0.20, 95% CI 0.08-0.50), were significantly less likely than men to be in good functional ability. Women's adjusted odds of being in good overall health state were similarly lower than men's; while income and household wealth status were stronger correlates of quality of life. HIV-infected participants reported better functional ability, quality of life and overall health state than HIV-affected participants. Discussion and Conclusions The enhanced healthcare received as part of anti-retroviral treatment as well as the considerable resources devoted to HIV care appear to benefit the overall well-being of HIV-infected older people; whereas similar resources have not been devoted to the general health needs of HIV uninfected older people. Given increasing numbers of older people, policy and programme interventions are urgently needed to holistically meet the health and well-being needs of older people beyond the HIV-related care system. <br/

Features of home and neighbourhood and the liveability of older South Africans

While older people live in developing countries, little is known about the relative importance of features of their communities in influencing their liveability. We examinecomponents of home and neighbourhood among older South Africans. Linear regression analyses revealed that features of home (basic amenities, household composition, financial status and safety) and neighbourhood (ability to shop for groceries, participate in organizations and feel safe from crime) are significantly associated with life satisfaction. Approaches to liveability that are person-centred and also set within contexts beyond home and neighbourhood are needed to addressboundaries between home and neighbourhood; incorporate personal resources into liveability models and import broader environmental contexts such as health and social policy

Scaling Laws for Polymers in Dissipative Particle Dynamics Revised

We present here a systematic study of dynamic behavior for polymer (PE) melt by means of Dissipative Particle Dynamics (DPD). We used DPD spring potential between adjacent segments. By changing various parameters related to spring potential like stiffness k, equilibrium distance r0 and parameters related to dynamic behavior like friction coefficient γ presented in dissipation force we tested their influence on scaling laws. We also compared these scaling laws obtained from our simulations with predictions from Rouse theory

A molecular simulation approach to the prediction of the morphology of self-assembled nanoparticles in diblock copolymers

Mixing microphase-separating diblock copolymers and nanoparticles can lead to the self-assembly of organic/inorganic hybrid materials that are spatially organized on the nanometre scale. Controlling particle location and patterns within the polymeric matrix domains remains, however, an unmet need. Computer simulation of such systems constitutes an interesting challenge since an appropriate technique would require the capturing of both the formation of the diblock mesophases and the copolymer-particle and particle-particle interactions, which can affect the ultimate structure of the material. In this work we discuss the application of Dissipative Particle Dynamics ( DPD) to the study of the distribution of nanoparticles with different degree of functionality and volume fraction in a lamellar microsegregated copolymer template. The DPD parameters of the systems were calculated according to a multi-step modelling approach, i.e., from lower scale (atomistic) simulations. The results show that positioning and ordering of the nanoparticles, as well as the dimensions of the block domains depend on covering extent and volume fraction, in full agreement with experiments. The overall results provide molecular-level information for the rational, a priori design of new polymer-particle nanocomposites with ad hoc, tailored properties

Modeling hierarchically structured nanoparticle/diblock copolymer systems

Despite progress in theories and simulations, the structure prediction of self-assembled materials beyond simple model systems remains a grand challenge. In this work, we present a molecular modeling approach for predicting the nanostructure of hybrid systems based on AB diblock copolymers and nanoparticles decorated with A, B, or mixed A/B homopolymer ligands. Using mesoscopic simulations, we derived phase diagrams as a function of nanoparticle concentration and decoration

Scaling Laws for Hairy Nanoparticle in Good Solvent

Scaling behavior of Hairy Nanoparticle in good solvent is studied by means of Dissipative Particle Dynamics (DPD). We studied gold spherical nanoparticle (Au) decorated by poly (styrene-b-2-vinylpyridine) (PS-PVP) diblock copolymer with PVP block attached to surface of Au nanoparticle. High grafting density, 1 chain/nm2, is considered. We utilized DPD model and interaction parameters from our previous work, on nanoparticle/diblock copolymer systems. We measured basic chain properties like End-to-end distance, Re, and Radius of Gyration, Rg. Moreover, the size of nanoparticle corona was measured by corresponding radial distribution functions and brush height, H(N), was obtained from End-monomer distribution. We tested the influence of (i) length of the PS-PVP chain and (ii) composition of PS-PVP chain on scaling behavior of Re, Rg and H(N), predicted by Daoud-Cotton model for polymer chains grafted onto the curved surfaces. Furthermore, we tested the influence of size of the spherical core on scaling behavior for selected PS-PVP chain lengths. Finally, we also discuss the scaling behavior for nanoparticle cores beyond spherical shape

Children's care and living arrangements in a high HIV prevalence area in rural South Africa

The objectives of this study were to describe the care and living arrangements of children in rural South Africa, focusing on differences between maternal, paternal and double orphans and non-orphans and to assess the prevalence and characteristics of 'child-only' households and 'child- and elderly-only' households in this setting. We analysed data from a longitudinal demographic information system using Mantel-Haenszel adjusted odds ratios and logistic regression. The prevalence of orphanhood almost doubled over the period 2000-2005. Maternal and double orphanhood prevalence increased more rapidly than paternal orphanhood, although most orphans are paternal orphans. Responsibility for paternal orphans' school fees and households is taken disproportionately by mothers. There is no evidence that it falls disproportionately to the young or elderly. Responsibility for maternal and double orphans' care is spread between different individuals with different ages, although the elderly have increased odds and fathers have decreased odds compared to non-orphans. Sixteen per cent of double orphans live in sibling-headed households, and most of these heads are over 18 years old. A high proportion of all children are responsible for their own day-to-day care and maternal orphans are more likely than non-orphans to care for themselves (age-adjusted). Seven per cent of maternal and double orphans and 2% of non- and paternal orphans live in 'child- and elderly-only' households. Two per cent of maternal and paternal orphans live in 'child-only' households, compared to 1% of non-orphans. Most of these children's school fees are the responsibility of non-resident parents. Understanding the reality of care and living arrangements is important to ensure that the needs of all children are met