Linear Dichroism Activity of Chiral Poly(p-Aryltriazole) Foldamers.

Controllable higher-order assembly is a central aim of macromolecular chemistry. An essential challenge to developing these molecules is improving our understanding of the structures they adopt under different conditions. Here, we demonstrate how flow linear dichroism (LD) spectroscopy is used to provide insights into the solution structure of a chiral, self-assembled fibrillar foldamer. Poly(para-aryltriazole)s fold into different structures depending on the monomer geometry and variables such as solvent and ionic strength. LD spectroscopy provides a simple route to determine chromophore alignment in solution and is generally used on natural molecules or molecular assemblies such as DNA and M13 bacteriophage. In this contribution, we show that LD spectroscopy is a powerful tool in the observation of self-assembly processes of synthetic foldamers when complemented by circular dichroism, absorbance spectroscopy, and microscopy. To that end, poly(para-aryltriazole)s were aligned in a flow field under different solvent conditions. The extended aromatic structures in the foldamer give rise to a strong LD signal that changes in sign and in intensity with varying solvent conditions. A key advantage of LD is that it only detects the large assemblies, thus removing background due to monomers and small oligomers.

Influence of DIBMA Polymer Length on Lipid Nanodisc Formation and Membrane Protein Extraction.

Polymer-based lipid nanoparticles like styrene-maleic acid lipid particles have revolutionized the study of membrane proteins. More recently, alternative polymers such as poly(diisobutylene-alt-maleic acid) (DIBMA) have been used in this field. DIBMA is commonly synthesized via conventional radical copolymerization. In order to study the influence of its chain length on lipid nanodisc formation and membrane protein extraction, we synthesized DIBMA with molar masses varying from 1.2-12 kDa via RAFT-mediated polymerization. For molar masses in the range of 3-7 kDa, the rate of lipid nanodisc formation was the highest and similar to those of poly(styrene-co-maleic acid) (SMA) and commercially available DIBMA. ZipA solubilization efficiency was significantly higher than for commercially available DIBMA and similar to SMA (circa 75%). Furthermore, RAFT-made DIBMA with a molar mass of 1.2-3.9 kDa showed a much cleaner separation on SDS-PAGE, without the smearing that is typically seen for SMA and commercially available DIBMA.

Prevalence and determinants of intimate partner violence against mothers of children under-five years in Central Malawi.

BACKGROUND: Intimate partner violence (IPV) against women is a global human rights violation and a public health problem. The phenomenon is linked to adverse health effects for women and children. Mothers of young children in Malawi can be particularly at risk because of gender-based power imbalances. The objectives of this study were to examine the prevalence and the risk factors of IPV against mothers of children under-five years of age in rural Malawi. METHODS: A multistage, cross-sectional study design was used. A sample of 538 mothers of young children was randomly selected from postnatal clinics in Dowa district. The WHO's Violence against women screening instrument was used to collect data. Logistic regressions were used to determine risk factors that were associated with IPV against mothers. RESULTS: Overall prevalence of all four forms of IPV against mothers of under-five children was 60.2%. The prevalence of IPV controlling behavior, psychological, physical, and sexual violence were 74.7, 49.4, 43.7 and 73.2% respectively. In multivariate analyses, mothers whose partners had extra marital affairs were more likely to experience controlling behavior (AOR: 4.97, 95% CI: 2.59-8.55, P = 0.001), psychological (AOR: 2.14, 95% CI: 1.486-3.472, P = 0.001) and physical (AOR: 2.29, 95% CI: 1.48-3.94, P = 0.001) violence than mothers whose partners did not have extra marital affairs. Mothers whose partners consume alcohol were more likely to experience sexual violence (AOR: 2.00, 95% CI: 1.17-3.41, P = 0.001) than mothers whose partners did not drink. Finally, mothers who spent more than 30 min drawing water were at greater risk of experiencing IPV than mothers who spent less than 30 min. CONCLUSION: This study found a significantly higher prevalence of IPV against mothers of under-five children in rural Malawi compared to women in the general population. Micro and macro-level programs aimed at mitigating the partners' potential risk behaviors identified in this study are suggested. Public health programs that support increased household access to safe water are also recommended to help undermine IPV against mothers.

Microwave decontamination of eyelid warming devices for the treatment of meibomian gland dysfunction.

PURPOSE: The role of bacteria in meibomian gland dysfunction is unclear, yet contamination of compresses used as treatment may exacerbate this condition. This study therefore determined the effect of heating on bacteria on two forms of compress. METHODS: Cotton flannels and MGDRx EyeBags (eyebags) were inoculated by adding experimental inoculum (Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa; one species for each set of 3 eyebags and flannels). One of each were then randomised in to 3 groups: no heating (control); therapeutic (47.4±0.7°C); or sanitisation (68±1.1°C). After treatment, bacteria cell numbers were calculated. The experiment was repeated in triplicate. RESULTS: There was a statistically significant difference between each treatment with the eyebag for S. aureus (control=7.15±0.11logC/ml, therapeutic heating=5.24±0.59logC/ml, sanitisation heating=3.48±1.43logC/ml; P<0.001) and S. pyogenes (7.36±0.13, 5.73±0.26, 4.75±0.54; P<0.001). P. aeruginosa also showed a significant reduction (P<0.001) from control (6.39±0.34) to therapeutic (0.33±0.26) and sanitisation (0.33±0.21), but the latter were similar (P=1.000). For the flannels, there was significant difference between each treatment for S. aureus (6.89±0.46, 3.96±1.76, 0.42±0.90; P<0.001). For S. pyogenes, there was a significant reduction (P<0.001) from control (7.51±0.10) to therapeutic (5.91±0.62) and sanitisation (5.18±0.8), but the latter were similar (P=0.07). For P. aeruginosa, there was a significant difference (P<0.001) from control (7.15±0.36) to sanitisation (5.83±0.44); but not to therapeutic (6.84±0.31) temperatures (P=0.07). CONCLUSIONS: Therapeutic heating produces a significant reduction in bacteria on the eyebags, but only sanitisation heating appears effective for flannels. However, patients should be advised to heat the eyebag to sanitisation temperatures on initial use.