ABSTRACT
Introduction: As individuals age, their sleep patterns change, and sleep disturbances can increase the risk of dementia. Poor sleep quality can be a risk factor for mild cognitive impairment (MCI) and dementia. Epidemiological studies show a connection between sleep quality and cognitive changes, with brain imaging revealing grey matter volume reduction and amyloid beta accumulation in Alzheimer's disease. However, most research has focused on Europeans, with little attention to other ethnic groups. Methods: This is a cross sectional study comparing effects across countries and ethnicities. Group 1 (n = 193) will be Indians residing in India (new participant recruitment), Group 2 will be South Asians residing in UK and group 3 will be Europeans residing in the UK. For group 2 and 3 (n = 193), data already collected by UK-based Southall and Brent REvisited (SABRE) tri-ethnic study will be used. For group 1, Pittsburgh Sleep Quality Index questionnaire (PSQI) will be used for assessment of sleep quality, Indian Council of Medical Research (Neurocognitive ToolBox) (ICMR-NCTB) for cognition testing and a 3 T MRI cerebral scan for brain morphometry. The data will be compared to sleep, cognitive function and brain MRI parameters from SABRE. Discussion: Racial and ethnic differences can impact the relationships of cognitive function, sleep quality and brain structure in older adults. Earlier studies have highlighted higher prevalence of poor sleep among black individuals compared to white individuals. Genetic or epigenetic mechanisms may contribute to these variations. Socio-cultural and environmental factors, such as neighbourhood, migration, lifestyle, stress and perceived discrimination may influence sleep patterns. The aim of the study is to examine the ethnogeographic variations in sleep quality, cognitive performance and brain morphometry among Indians living in India, and South Asians and Europeans residing in the UK.
ABSTRACT
Wire arc additive manufacturing (WAAM) offers a high rate of material deposition among various additive manufacturing techniques with wire as feedstock material but has not been established for zinc alloys. Zn alloys can be used as degradable biomaterials, in contrast to conventional permanent metallic biomaterials. In this work, commercially pure Zn was processed by WAAM to obtain near-dense parts, and the properties obtained through WAAM-processed Zn were compared with wrought (WR) Zn samples. The microstructure and hardness values of the WAAM (41 ± 1 HV0.3) components were found to be similar to those of the WR (35 ± 2 HV0.3) components. Bulk X-ray diffraction texture measurements suggested that WAAM builds exhibit a heavily textured microstructure compared to the WR counterparts, with peak intensities around <3 3−6 2> or <0 0 0 2> in the directions parallel to the build direction (BD). The corrosion rates in simulated body fluid (SBF) were similar for WAAM (0.45 mmpy) and WR (0.3 mmpy) samples. The weight loss measurements in SBF were found to be marginally higher in the WAAM samples compared to the WR counterparts for a duration of up to 21 days. MC3T3-E1 preosteoblasts were found to be healthy and proliferating in the culture medium containing the degradation products from WAAM-Zn in a manner similar to WR-Zn. This work establishes the feasibility of processing Zn by WAAM for use in bioresorbable metallic implants.
