Inhibiting the Thermal Gelation of Copolymer Stabilized Nonaqueous Dispersions and the Synthesis of Full Color PMMA Particles

Polymeric particle dispersions have numerous potential applications; currently one of the most relevant is their use as inks in electrophoretic displays. These colloidal particles are synthesized from the appropriate monomer using nonaqueous dispersion (NAD) polymerization in a nonpolar solvent, which requires a stabilizer to control particle size and morphology. We have previously reported the facile synthesis of poly(methyl methacrylate)-block-poly(octadecyl acrylate) (PMMA-b-PODA) by atom transfer radical polymerization (ATRP), and its use in the NAD polymerization of MMA in hexane/dodecane solvent mixtures. Here we report the synthesis of monodisperse PMMA particles in dodecane following a standard “industrial” procedure using these PMMA-b-PODA stabilizers. However, it was observed that the particle suspensions solidified when they were left at temperatures below ?18 °C yet redispersed upon being heated. Differential scanning calorimetry, dynamic light scattering, and rheological studies demonstrated that this thermoresponsive behavior was due to a liquid–gel transition occurring at 17.5 °C as a consequence of the upper critical solution temperature of PODA in dodecane being traversed. Consequently, new copolymers were synthesized by ATRP with an ethylhexyl acrylate (EHA) co-monomer incorporated into the lyophilic (dodecane compatible) block. Dispersions stabilized by these PMMA-b-P(ODA-co-EHA) polymers with high EHA contents exhibited lower gelation temperatures because of the greater solvent compatibility with dodecane. The use of a PMMA65-b-(ODA10-co-EHA45) copolymer stabilizer (with the highest EHA content) gave PMMA dispersions that showed no gelation down to 4 °C and monodisperse cross-linked PMMA particles containing organic dyes (cyan, magenta, red, and black) giving colored particles across the size range of approximately 100–1300 nm

Chemical Vapor Detecting Passive RFID Tag

A Radio Frequency Identification (RFID) Tag is designed for threshold detection of certain chemical vapors. The vapor presence is signaled to the reader by a digital alert and communication between the tag and reader is not interrupted. The detection mechanism comprises an inkjet printed conducting track on an elastomer that swells in response to vapor exposure. The expanded track breaks and triggers a tamper detection circuit integrated into the RFID tag transponder chi

Bone mineral content after renal transplantation

Forearm bone mineral content (BMC), as evaluated by photonabsorption densitometry, was measured in 28 cadaver kidney donor recipients who entered the study 8 weeks postoperatively and were followed up for 18 months. BMC decreased signifiantly (p<0.05) but marginally in placebo-treated patients (n=14) (initial BMC 1.09±0.25 g/cm; final BMC 1.05±0.24). Fourteen patients were prophylactically given 1,25(OH)2vitamin D3 in a dose which avoided hypercalcemia and hypercalciuria (sim0.25 µg/day); under 1,25(OH)2 vitamin D3 prophylaxis a significant decrease of forearm BMC was observed no longer (initial BMC 0.94±0.21 g/cm; final BMC 0.95±0.21), but the difference between placebo and 1,25(OH)2 vitamin D3 narrowly missed statistical significance (p=0.066). It is concluded that the decrease of forearm BMC is negligible in transplant recipients with low steroid regimens. The data suggest a trend for prophylaxis with 1,25(OH)2 vitamin D3 to slightly ameliorate forearm (cortical) BMC loss

A multicenter prospective randomized controlled trial investigating the effects of combustion-free nicotine alternatives on cardiovascular risk factors and metabolic parameters in individuals with type 2 diabetes who smoke: the DiaSmokeFree study protocol

Stopping smoking is crucial for public health and especially for individuals with diabetes. Combustion-free nicotine alternatives like e-cigarettes and heated tobacco products are increasingly being used as substitutes for conventional cigarettes, contributing to the decline in smoking prevalence. However, there is limited information about the long-term health impact of those products in patients with diabetes. This randomized controlled trial aims to investigate whether switching from conventional cigarettes to combustion-free nicotine alternatives will lead to a measurable improvement in cardiovascular risk factors and metabolic parameters over a period of 2 years in smokers with type 2 diabetes. The multicenter study will be conducted in seven sites across four countries. A total of 576 smokers with type 2 diabetes will be randomly assigned (1:2 ratio) to either standard of care with brief cessation advice (Control Arm) or combustion-free nicotine alternatives use (Intervention Arm). The primary end point is the change in the proportion of patients with metabolic syndrome between baseline and the 2-year follow-up. Additionally, the study will analyze the absolute change in the sum of the individual factors of metabolic syndrome at each study time point. Patient recruitment has started in September 2021 and enrollment is expected to be completed by December 2023. Results will be reported in 2026. This study may provide valuable insights into cardiovascular and metabolic health benefits or risks associated with using combustion-free nicotine alternatives for individuals with type 2 diabetes who are seeking alternatives to tobacco cigarette smoking. The study protocol, informed consent forms, and relevant documents were approved by seven ethical review boards. Study results will be disseminated through articles published in high-quality, peer-reviewed journals and presentations at conferences

Drug delivery into microneedle-porated nails from nanoparticle reservoirs

Copyright © 2015. Published by Elsevier B.V.Author's post-print version. The definitive version is available from the publisher via doi: 10.1016/j.jconrel.2015.10.026This study demonstrates the potential of polymeric nanoparticles as drug reservoirs for sustained topical drug delivery into microneedle-treated human nail. Laser scanning confocal microscopy was used to image the delivery of a fluorescent model compound from nanoparticles into the nail. A label-free imaging technique, stimulated Raman scattering microscopy, was applied, in conjunction with two-photon fluorescence imaging, to probe the disposition of nanoparticles and an associated lipophilic 'active' in a microneedle-porated nail. The results provide clear evidence that the nanoparticles function as immobile reservoirs, sequestered on the nail surface and in the microneedle-generated pores, from which the active payload can be released and diffuse laterally into the nail over an extended period of time

Multiple stressors in Southern Africa: the link between HIV/AIDS, food insecurity, poverty and children's vulnerability now and in the future

Several countries in Southern Africa now see large numbers of their population barely subsisting at poverty levels in years without shocks, and highly vulnerable to the vagaries of the weather, the economy and government policy. The combination of HIV/AIDS, food insecurity and a weakened capacity for governments to deliver basic social services has led to the region experiencing an acute phase of a long-term emergency. “Vulnerability” is a term commonly used by scientists and practitioners to describe these deteriorating conditions. There is particular concern about the “vulnerability” of children in this context and implications for children's future security. Through a review of literature and recent case studies, and using a widely accepted conceptualisation of vulnerability as a lens, we reflect on what the regional livelihoods crisis could mean for children's future wellbeing. We argue that an increase in factors determining the vulnerability of households — both through greater intensity and frequency of shocks and stresses (“external” vulnerability) and undermined resilience or ability to cope (“internal” vulnerability) — are threatening not only current welfare of children, but also their longer-term security. The two specific pathways we explore are (1) erosive coping strategies employed by families and individuals; and (2) their inability to plan for the future. We conclude that understanding and responding to this crisis requires looking at the complexity of these multiple stressors, to try to comprehend their interconnections and causal links. Policy and programme responses have, to date, largely failed to take into account the complex and multi-dimensional nature of this crisis. There is a misfit between the problem and the institutional response, as responses from national and international players have remained relatively static. Decisive, well-informed and holistic interventions are needed to break the potential negative cycle that threatens the future security of Southern Africa's children

Effectiveness of laxatives in elderly - a cross sectional study in nursing homes

<p>Abstract</p> <p>Background</p> <p>Laxatives are efficient drugs, but the effectiveness has been questioned. In nursing homes, the prevalence of constipation is high and laxatives are commonly used drugs. The aims of the study were to assess the effectiveness of laxative therapy in an everyday setting in Norwegian nursing homes, study differences between treatment regimens and factors associated with normal bowel function.</p> <p>Methods</p> <p>A cross-sectional study. After giving informed consent, residents above 60 years of age using laxatives for functional constipation were included, and their characteristics, medical history, use of drugs and bowel functions were recorded. Normal bowel function was defined as bowel movements from 3 times/week to 3 times/day and stool consistency 3-5 on Bristol Stool Form Scale.</p> <p>Results</p> <p>Out of 647 residents in the nursing homes, 197 were included and 116 (59%) had normal bowel function. The treatment effect did not differ significantly between the laxatives, treatment regimens or expected efficacy of the regimens. The treatment was unsatisfactorily adapted to individual needs. In subjects with normal bowel function, 113 (97%) had persistent complaints; 68 (59.5%), 10 (8.0%), 34 (28.6%) and 26 (22.5%) reported straining, manual manoeuvre to facilitate bowel movements, feeling of incomplete bowel movements, and feeling of anorectal obstruction respectively. Good nutritional status, previous or present cancer disease and anxiety/depression were predictors of normal bowel function.</p> <p>Conclusions</p> <p>Treatment of constipation in nursing homes was unsatisfactory. Nearly all patients with normal stool frequency and consistence had some persistent complaints. Improved nutrition and individualization of the treatment could improve the outcome.</p