A Cross-Sectional Study of Myopia and Morning Melatonin Status in Northern Irish Adolescent Children.

Purpose: Previous studies have demonstrated an association between melatonin status and both refractive error and axial length in young adult myopes. This study aimed to determine if this relationship extends to a younger adolescent cohort. Methods: Healthy children aged 12-15 years provided morning saliva samples before attending Ulster University (55°N) for cycloplegic autorefraction and axial length measures. Participants completed questionnaires describing recent sleep habits and physical activity. Salivary melatonin was quantified using high-performance liquid chromatography-tandem mass spectrometry. Data collection for all participants occurred over a 1-week period (April 2021). Results: Seventy participants aged 14.3 (95% CI: 14.2-14.5) years were categorised by spherical equivalent refraction [SER] (range: -5.38DS to +1.88DS) into two groups; myopic SER ≤ -0.50DS (n = 22) or nonmyopic -0.50DS < SER ≤ +2.00DS (n = 48). Median morning salivary melatonin levels were 4.52 pg/ml (95% CI: 2.60-6.02) and 4.89 pg/ml (95% CI: 3.18-5.66) for myopic and nonmyopic subjects, respectively, and did not differ significantly between refractive groups (P = 0.91). Melatonin levels were not significantly correlated with SER, axial length, sleep, or activity scores (Spearman's rank, all P > 0.39). Higher levels of physical activity were associated with higher sleep quality (Spearman's rank, ρ = -0.28, P = 0.02). Conclusion: The present study found no significant relationship between morning salivary melatonin levels and refractive error or axial length in young adolescents. This contrasts with outcomes from a previous study of adults with comparable methodology, season of data collection, and geographical location. Prospective studies are needed to understand the discrepancies between adult and childhood findings and evaluate whether melatonin levels in childhood are indicative of an increased risk for future onset of myopia and/or faster axial growth trajectories and myopia progression in established myopes. Future work should opt for a comprehensive dim-light melatonin onset protocol to determine circadian phase.

Vitamin D Status and Health Outcomes in School Children in Northern Ireland: Year One Results from the D-VinCHI Study.

(1) Background: Vitamin D status has never been investigated in children in Northern Ireland (UK). (2) Methods: Children (4-11 years) (n = 47) were recruited from November 2019 to March 2020 onto the cross-sectional study. Anthropometry was assessed. Plasma 25-hydroxyvitamin D (25(OH)D) was analysed. Vitamin D intake, parental knowledge and perceptions, participant habits, physical activity and sedentary behaviour were established via questionnaire. Muscle strength was assessed via isometric grip strength dynamometry and balance via dominant single-leg and tandem stance. Parathyroid hormone, bone turnover markers (OC, CTX and P1NP), glycated haemoglobin and inflammatory markers (CRP, IFN-γ, IL-10, IL-12p70, IL-13, IL-1ß, IL-2, IL-4, IL-6, IL-8 and TNF-α) were analysed. (3) Results: Mean (SD) 25(OH)D was 49.17 (17.04) nmol/L (n = 47); 44.7% of the children were vitamin D sufficient (25(OH)D >50 nmol/L), 48.9% were insufficient (25-50 nmol/L) and 6.4% were deficient (<25 nmol/L). 25(OH)D was positively correlated with vitamin D intake (µg/day) (p = 0.012, r = 0.374), spring/summer outdoor hours (p = 0.006, r = 0.402) and dominant grip strength (kg) (p = 0.044, r = 0.317). Vitamin D sufficient participants had higher dietary vitamin D intake (µg/day) (p = 0.021), supplement intake (µg/day) (p = 0.028) and spring/summer outdoor hours (p = 0.015). (4) Conclusion: Over half of the children were vitamin D deficient or insufficient. Wintertime supplementation, the consumption of vitamin D rich foods and spring/summer outdoor activities should be encouraged to minimise the risk of vitamin D inadequacy.

Assessing the Oxidative Degradation of N-Methylpyrrolidone (NMP) in Microelectronic Fabrication Processes by Using a Multiplatform Analytical Approach.

During the construction of recording head devices, corrosion of metal features and subsequent deposition of corrosion by-products have been observed. Previous studies have determined that the use of N-methylpyrrolidone (NMP) may be a contributing factor. In this study, we report the use of a novel multiplatform analytical approach comprising of pH, liquid chromatography/UV detection (LC/UV), inductively coupled plasma optical emission spectroscopy (ICP-OES), and LC/mass spectrometry (LC/MS) to demonstrate that reaction conditions mimicking those of general photoresist removal processes can invoke the oxidation of NMP during the photolithography lift-off process. For the first time, we have confirmed that the oxidation of NMP lowers the pH, facilitating the dissolution of transition metals deposited on wafer substrates during post-mask and pre-lift-off processes in microelectronic fabrication. This negatively impacts upon the performance of the microelectronic device. Furthermore, it was shown that, by performing the process in an inert atmosphere, the oxidation of NMP was suppressed and the pH was stabilized, suggesting an affordable modification of the photolithography lift-off stage to enhance the quality of recording heads. This novel study has provided key data that may have a significant impact on current and future fabrication process design, optimization, and control. Results here suggest the inclusion of pH as a key process input variable (KPIV) during the design of new photoresist removal processes.

Rhamnolipids from Pseudomonas aeruginosa strain W10; as antibiofilm/antibiofouling products for metal protection.

Industrial biofouling-problems associated with the accumulation of microorganisms from flowing water and fluids on processing surfaces can cause severe problems. A Pseudomonas aeruginosa strain W10 was isolated from industrial setting and found to produce predominantly di-rhamnolipids (Rha-Rha-C10-C10) with a yield of around 10 g L-1 and a critical micelle concentration (CMC) of 80 mg L-1 . P. aeruginosa W10 rhamnolipids were able to disrupt up to 99% of 48 h pre-formed biofilms of the Gram-positive organisms Bacillus licheniformis CAN55, Staphylococcus capitis SH6, and a mixed culture (strains CAN55, SH6, and W10), under static conditions, at concentrations of 0.1, 0.5, and 1 mg ml-1 on a stainless steel surface commonly used in industrial process pipelines. CFU measurements and LIVE/DEAD BacLight staining confirmed these observations. Furthermore, a purified di-rhamnolipid fraction was found to be responsible for the microbial inhibition of B. licheniformis strain CAN55. This study provides evidence that rhamnolipids may have valuable applications in preventing biofilms and biofouling in industrial plants and, in a wider context, may also apply to metal medical devices.