Responsive, functional materials from self-stabilising and reactive branched addition co-polymers

A one-component emulsion templating strategy for the preparation of inorganic-organic encapsulated droplets and hollow capsules has been developed. The process exploits, and relies on, both branched addition co-polymer architectures and compositions, which provide simultaneous properties of emulsion droplet steric-stabilisation and cross-linking function. It was demonstrated that high yielding encapsulation of different hydrophobic actives was successful whilst retaining the structural integrity of the capsule compartments. Responsive capsule surfaces and shell/membrane properties with pre-determined complex functionalities were demonstrated. The incorporation of chemical functionality within the reactive branched addition co-polymer allowed higher order responsive structures to be formed. These materials have been shown to be highly useful in the preparation of large associated aggregates which can be loaded with numerous payloads. The encapsulation of both hydrophobic dyes and an oil-soluble polymer was illustrated. Protocell constructs with pH-mediated, electrostatically gated permeability were prepared by covalently grafting a multi-responsive functional terpolymer to the outer surface of a cross-linked membrane of silica nanoparticle-based colloidosomes. Terpolymer grafted membrane functionality-mediated uptake and release of small molecules from the colloidosomes was demonstrated.Open Acces

Radiation doses and associated risks from x-ray guided cardiac catheterization procedures in children and young adults

PhD ThesisCardiac catheterizations are an essential procedure in the management of patients with congenital and acquired heart conditions. However, associated radiation doses are often high, raising concerns over potentially increased cancer risks. Neither the radiation doses, nor the associated risks, have been adequately investigated in young people undergoing these procedures. A cohort was established of around 13,500 patients aged under 22 years who have undergone cardiac catheterizations in England. Organ doses were estimated based on a dosimetry system utilising data from Monte Carlo simulations. Doses were highest for the lungs (median: 17.6 millisieverts, mSv) and heart (13.6 mSv), while doses to bone marrow (2.6 mSv) and the thyroid (0.7 mSv) were relatively low. Radiation doses have fallen by a factor of up to ten during the study period. The results were compared to equivalent figures derived from physical measurements. Uncertainties in dose estimates were calculated. These were around ±30%, though were potentially much higher for breast dose. The risk of cancer in relation to estimated doses was calculated using BEIR VII risk models. For examinations conducted using modern equipment, these risks are around 1 in 1700. A small epidemiological analysis was performed, suggesting a nearly threefold increased risk of cancer in the cohort, compared to the general UK population. There are a number of reasons to suggest that this increase was primarily not related to radiation exposure, most notably the large impact of transplantation and likely associated immunosuppressant use. Despite the high cancer incidence, the overall survival in the cohort was high, at around 91% after 30 years. Conclusion: The study provides the first large scale estimation of organ doses from cardiac catheterizations among this age group. Rates of cancer among this patient group are high, although this is appears to be mostly due to factors other than radiation exposure.British Heart Foundatio

Responsive feeding: establishing healthy eating behaviour early on in life

Responsive feeding (RF) refers to a reciprocal relationship between an infant or child and his or her caregiver that is characterised by the child communicating feelings of hunger and satiety through verbal or nonverbal cues, followed by an immediate response from the caregiver. The response includes the provision of appropriate and nutritious food in a supportive manner, while maintaining an appropriate feeding environment. The literature indicates that RF is the foundation for the development of healthy eating behaviour and optimal skills for self-regulation and self-control of food intake. Therefore, practising RF is associated with ideal growth standards, optimal nutrient intake and long-term regulation of weight. On the other hand, nonresponsive feeding (NRF) practices are associated with feeding problems and the development of under- or overnutrition. Different types of NRF behaviour have been described, where the caregiver is either uninvolved during meals, too restrictive or controlling, or allows the child to control mealtimes. Consequently, mealtimes may become cumbersome, characterised by inconsistent, nonresponsive interaction, and may result in a relationship that is lacking in trust. The effects of RF and NRF are reviewed in this article and the practical guideline to “Feed slowly and patiently, and encourage your baby to eat, but do not force them” is suggested as appropriate for inclusion in the proposed South African paediatric Food Based Dietary Guidelines. It is also acknowledged that RF practices are best established when mothers choose to breastfeed on demand, as they are less controlling and moreresponsive to their infants’ internal hunger and satiety cues

A simple Bayesian linear excess relative risk model

A new Bayesian Poisson relative risk model is proposed for displaying the excess relative risk associated to a unique exposure as a probability distribution in a closed form. The background risk can be modelled by a unique two levels factor, e.g. gender or smoking status.Cancer Research U

Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease

Background. Cardiovascular diseases (CVDs) are defined as conditions involving decreased blood flow to the heart that can lead to heart attacks, stroke or other disorders. CVDs are a common cause of death in low- and middle-income countries. In South Africa (SA) in particular, CVD is the leading cause of death after HIV/AIDS, responsible for 1 in 6 deaths. CVD risk factors include unhealthy diets, hypertension, obesity, high cholesterol levels and diabetes. Omega-3 fatty acids may have a protective role in the risk of developing heart disease.Objectives. To evaluate the consequences of an increased intake of fish and plant-based omega-3 fatty acids on the risk of CVD mortality and events.Methods. The inclusion criteria for this review were randomised controlled trials (RCTs) lasting at least 12 months, which investigated men and women aged ≥18 years. These participants had to be at any risk of CVD while receiving dietary supplements and an advised diet to promote the intake of omega-3. This diet included oily fish, fish oils and seeds rich in omega-3. Comparisons with the interventions included the participants’ usual diet, no advice, no supplements, placebo or lower-dose omega-3. The review evaluated the effectiveness of these interventions on primary (e.g. CVD deaths and events), secondary (e.g. major adverse cerebrovascular or CVD events, body weight and other adiposity measures, and lipids) and tertiary (e.g. blood pressure and side-effects) outcomes.Results. Evidence from this review indicates that increasing the intake of long-chain omega-3 fatty acids (LCn3) or alpha-linolenic acid (ALA) probably has little or no effect on all-cause CVD or coronary heart disease mortality. Evidence was of moderate certainty, except for all-cause mortality, where there was a high certainty.Conclusions. According to moderate- to high-certainty evidence, short-chain fatty acids and LCn3 have little or no effect on mortality or cardiovascular health. However, omega-3 ALA slightly reduces the risk of CVD events and arrhythmias

Anonymising Clinical Data for Secondary Use

Secondary use of data already collected in clinical studies has become more and more popular in recent years, with the commitment of the pharmaceutical industry and many academic institutions in Europe and the US to provide access to their clinical trial data. Whilst this clearly provides societal benefit in helping to progress medical research, this has to be balanced against protection of subjects' privacy. There are two main scenarios for sharing subject data: within Clinical Study Reports and Individual Patient Level Data, and these scenarios have different associated risks and generally require different approaches. In any data sharing scenario, there is a trade-off between data utility and the risk of subject re-identification, and achieving this balance is key. Quantitative metrics can guide the amount of de-identification required and new technologies may also start to provide alternative ways to achieve the risk-utility balance.Comment: 25 page

Fat Mass and Obesity-Associated (FTO) Gene Polymorphisms Are Associated with Physical Activity, Food Intake, Eating Behaviors, Psychological Health, and Modeled Change in Body Mass Index in Overweight/Obese Caucasian Adults

The fat mass and obesity-associated (FTO) gene is currently recognized as the most robust predictor of polygenic obesity. We investigated associations between the FTO rs1421085 and rs17817449 polymorphisms and the FTO rs1421085–rs17817449 haplotype and dietary intake, eating behavior, physical activity, and psychological health, as well as the effect of these associations on BMI. N = 133 treatment seeking overweight/obese Caucasian adults participated in this study. Genotyping was performed from whole blood samples. Weight and height was measured and a non-quantified food frequency questionnaire was completed to assess food group intake. Validated questionnaires were completed to assess physical activity (Baecke questionnaire), psychological health (General Health questionnaire, Rosenburg self-esteem scale and Beck Depression Inventory), and eating behavior (Three Factor Eating questionnaire). The risk alleles of the FTO polymorphisms were associated with poorer eating behaviors (higher hunger, internal locus for hunger, and emotional disinhibition scores), a higher intake of high fat foods and refined starches and more depressive symptoms. The modeled results indicate that interactions between the FTO polymorphisms or haplotypes and eating behavior, psychological health, and physical activity levels may be associated with BMI. The clinical significance of these results for implementation as part of weight management interventions needs further investigation

Electrostatically gated membrane permeability in inorganic protocells

Although several strategies are now available to produce functional microcompartments analogous to primitive cell-like structures, little progress has been made in generating protocell constructs with self-controlled membrane permeability. Here we describe the preparation of water-dispersible colloidosomes based on silica nanoparticles and delineated by a continuous semipermeable inorganic membrane capable of self-activated, electrostatically gated permeability. We use crosslinking and covalent grafting of a pH-responsive copolymer to generate an ultrathin elastic membrane that exhibits selective release and uptake of small molecules. This behaviour, which depends on the charge of the copolymer coronal layer, serves to trigger enzymatic dephosphorylation reactions specifically within the protocell aqueous interior. This system represents a step towards the design and construction of alternative types of artificial chemical cells and protocell models based on spontaneous processes of inorganic self-organization