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

Increase in childhood asthma admissions in an urbanising population

Objective. In South Africa, rapid urbanisation has increased the risk of childhood asthma. This report reviews the pattern of asthma admissions to the Paediatric Department of Ga-Rankuwa Hospital, South Africa, from 1986 to 1996. Design. Inpatient admission data were reviewed for 1986- 1996. A detailed analysis of the records of asthma patients admitted between 1992 and 1996 was done. Outpatient data were reviewed from 1992.Setting. Ga-Rankuwa Hospital, situated on the border of the Gauteng and orth West provinces of South Africa and serving a large black population in various stages of urbanisation.Main outcome measures. Trends in admission numbers and demographic characteristics.Results. Asthma admissions were 2.5 times higher in 1996 than 1986. The greatest increase in admissions was in the 1 - 47-month age group. The male to female ratio was 1.5:1. More patients came from urban than from rural areas. Admissions peaked during the summer. Re-admissions occurred most frequently within 3 months of the first admission.Conclusion. Paediatric asthma admissions have shown an increase in the past decade. This may be associated with changes in the environment of the community. There is a need for preventive programmes for asthma at community and national level

Effect of ospemifene on moderate or severe symptoms of vulvar and vaginal atrophy.

Objectives To determine whether assessment of all moderate-to-severe symptoms at baseline gives a more accurate evaluation of the treatment effect of ospemifene in vulvovaginal atrophy (VVA) than the most bothersome symptom (MBS) approach. Methods Data were pooled from two pivotal phase-III clinical trials evaluating the efficacy and safety of oral ospemifene 60 mg/day for the treatment of symptoms of VVA (n = 1463 subjects). Symptoms of vaginal dryness, dyspareunia, and vaginal and/or vulvar irritation/itching reported as moderate or severe at baseline were evaluated. Clinically relevant differences between ospemifene and placebo were analyzed using a four-point severity scoring system and presented as improvement, substantial improvement, or relief. Results Subjects in these studies reported statistically significant improvement, substantial improvement, and relief for vaginal dryness (p \u3c 0.00001), dyspareunia (p \u3c 0.001) and statistically significant improvement and relief for vaginal and/or vulvar irritation/itching (p \u3c 0.01) from baseline to week 12 with ospemifene compared with placebo. A similar trend was observed for women who reported substantial improvement of vaginal and/or vulvar irritation/itching. Conclusions For drug registration purposes, the use of the MBS model is appealing because of its simplicity and ease of scientific validation. However, the MBS model may underestimate the total magnitude of the clinical benefit of ospemifene treatment for symptomatic women suffering from VVA

Effect of ospemifene on moderate or severe symptoms of vulvar and vaginal atrophy.

Objectives To determine whether assessment of all moderate-to-severe symptoms at baseline gives a more accurate evaluation of the treatment effect of ospemifene in vulvovaginal atrophy (VVA) than the most bothersome symptom (MBS) approach. Methods Data were pooled from two pivotal phase-III clinical trials evaluating the efficacy and safety of oral ospemifene 60 mg/day for the treatment of symptoms of VVA (n = 1463 subjects). Symptoms of vaginal dryness, dyspareunia, and vaginal and/or vulvar irritation/itching reported as moderate or severe at baseline were evaluated. Clinically relevant differences between ospemifene and placebo were analyzed using a four-point severity scoring system and presented as improvement, substantial improvement, or relief. Results Subjects in these studies reported statistically significant improvement, substantial improvement, and relief for vaginal dryness (p \u3c 0.00001), dyspareunia (p \u3c 0.001) and statistically significant improvement and relief for vaginal and/or vulvar irritation/itching (p \u3c 0.01) from baseline to week 12 with ospemifene compared with placebo. A similar trend was observed for women who reported substantial improvement of vaginal and/or vulvar irritation/itching. Conclusions For drug registration purposes, the use of the MBS model is appealing because of its simplicity and ease of scientific validation. However, the MBS model may underestimate the total magnitude of the clinical benefit of ospemifene treatment for symptomatic women suffering from VVA

Morphological Variation in the Wild-Weedy Complex of Sorghum Bicolour In Situ in Western Kenya: Preliminary Evidence of Crop-To-Wild Gene Flow ?

Crop wild relatives are important components of agroecosystems and have over the years been exploited in breeding programs as sources of genes for novel traits. Information on the extent and patterns of variability is important in formulating effective conservation and utilization strategies for existing crop wild relative populations. We conducted surveys and collections of wild and weedy accessions of Sorghum bicolor (L.) Moench in Lambwe Valley in western Kenya in order to investigate occurrence, distribution, and morphological variability in the wild-weedy complex of S. bicolor under local agroecological conditions. We also attempted to understand the role, if any, of crop-to-wild gene flow in structuring variability within and among populations. The morphological data presented here showed wide variability within wild-weedy sorghum populations with respect to habitats and morphotypes. True wild sorghum populations in national parks and the sugarcane belt were clearly distinguishable from the putative hybrids or intermediate forms found in sorghum fields, in sorghum field margins, and, to some extent, by the roadside near sorghum fields. The existence of these intermediate forms is empirical evidence of introgression between cultivated sorghum and its wild-weedy relatives. Extensive introgression, especially within in situ conservation areas and/or in areas of high diversity, would lead to genetic erosion and possible depletion of these important wild sorghum genetic resources

Susceptibility to a sexually transmitted disease in a wild koala population shows heritable genetic variance but no inbreeding depression

The koala, one of the most iconic Australian wildlife species, is facing several concomitant threats that are driving population declines. Some threats are well known and have clear methods of prevention (e.g., habitat loss can be reduced with stronger land-clearing control), whereas others are less easily addressed. One of the major current threats to koalas is chlamydial disease, which can have major impacts on individual survival and reproduction rates and can translate into population declines. Effective management strategies for the disease in the wild are currently lacking, and to date we know little about the determinants of individual susceptibility to disease. Here we investigated the genetic basis of variation in susceptibility to chlamydia using one of the most intensively studied wild koala populations. We combined data from veterinary examinations, chlamydia testing, genetic sampling and movement monitoring. Out of our sample of 342 wild koalas, 60 were found to have chlamydia. Using genotype information on 5007 SNPs to investigate the role of genetic variation in determining disease status, we found no evidence of inbreeding depression, but a heritability of 0.11 (95%CI = 0.05 – 0.23) for the probability that koalas had chlamydia. Heritability of susceptibility to chlamydia could be relevant for future disease management, as it suggests adaptive potential for the population

HIV Prevalence and Incidence among Sexually Active Females in Two Districts of South Africa to Determine Microbicide Trial Feasibility

Background: The suitability of populations of sexually active women in Madibeng (North-West Province) and Mbekweni (Western Cape), South Africa, for a Phase III vaginal microbicide trial was evaluated. Methods: Sexually active women 18-35 years not known to be HIV-positive or pregnant were tested cross-sectionally to determine HIV and pregnancy prevalence (798 in Madibeng and 800 in Mbekweni). Out of these, 299 non-pregnant, HIV-negative women were subsequently enrolled at each clinical research center in a 12-month cohort study with quarterly study visits. Results: HIV prevalence was 24% in Madibeng and 22% in Mbekweni. HIV incidence rates based on seroconversions over 12 months were 6.0/100 person-years (PY) (95% CI 3.0, 9.0) in Madibeng and 4.5/100 PY (95% CI 1.8, 7.1) in Mbekweni and those estimated by cross-sectional BED testing were 7.1/100 PY (95% CI 2.8, 11.3) in Madibeng and 5.8/100 PY (95% CI 2.0, 9.6) in Mbekweni. The 12-month pregnancy incidence rates were 4.8/100 PY (95% CI 2.2, 7.5) in Madibeng and 7.0/100 PY (95% CI 3.7, 10.3) in Mbekweni; rates decreased over time in both districts. Genital symptoms were reported very frequently, with an incidence of 46.8/100 PY (95% CI 38.5, 55.2) in Madibeng and 21.5/100 PY (95% CI 15.8, 27.3) in Mbekweni. Almost all (>99%) participants said that they would be willing to participate in a microbicide trial. Conclusion: These populations might be suitable for Phase III microbicide trials provided that HIV incidence rates over time remain sufficiently high to support endpoint-driven trial

Reissner-Nordstrom Black Holes and Thick Domain Walls

We solve numerically equations of motion for real self-interacting scalar fields in the background of Reissner-Nordstrom black hole and obtained a sequence of static axisymmetric solutions representing thick domain walls charged black hole systems. In the case of extremal Reissner-Nordstrom black hole solution we find that there is a parameter depending on the black hole mass and the width of the domain wall which constitutes the upper limit for the expulsion to occur.Comment: 18 pages, 10 figures, accepted for Phys. Rev.

Cohort profile: biological pathways of risk and resilience in Syrian refugee children (BIOPATH)

The BIOPATH cohort was established to explore the interplay of psychosocial and biological factors in the development of resilience and mental health problems in Syrian refugee children. Based in Lebanon, a middle-income country significantly impacted by the refugee crisis, it is the first such cohort of refugees in the Middle East. Families were recruited from informal tented settlements in the Beqaa region using purposive cluster sampling. At baseline (October 2017–January 2018), N = 3188 individuals participated [n = 1594 child–caregiver dyads; child gender, 52.6% female; mean (SD) age = 11.44 (2.44) years, range = 6–19]. Re-participation rate at 1-year follow-up was 62.8%. Individual interviews were conducted with children and primary caregivers and biological samples collected from children. Measures include: (1) children’s well-being and mental health problems (using tools validated against clinical interviews in a subsample of the cohort); (2) psychosocial risk and protective factors at the level of the individual (e.g. coping strategies), family (e.g. parent–child relationship), community (e.g. collective efficacy), and wider context (e.g. services); (3) saliva samples for genetic and epigenetic (methylation) analyses; (4) hair samples to measure cortisol, dehydroepiandrosterone (DHEA) and testosterone. This cohort profile provides details about sampling and recruitment, data collection and measures, demographic data, attrition and potential bias, key findings on resilience and mental health problems in children and strengths and limitations of the cohort. Researchers interested in accessing data should contact Professor Michael Pluess at Queen Mary University of London, UK (e-mail: [email protected]). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00127-022-02228-8