Colloidal gold nanoparticles (AuNPs) were prepared from two different liquid precursors (gold (III) acetate and gold (III) chloride), using the Ultrasonic Spray Pyrolysis (USP) process. The STEM ...characterisation showed that the AuNPs from gold chloride are spherical, with average diameters of 57.2 and 69.4 nm, while the AuNPs from gold acetate are ellipsoidal, with average diameters of 84.2 and 134.3 nm, according to Dynamic Light Scattering (DLS) measurements. UV/VIS spectroscopy revealed the maximum absorbance band of AuNPs between 532 and 560 nm, which indicates a stable state. Colloidal AuNPs were used as starting material and were mixed together with acrylic acid (AA) and acrylamide (Am) for the free radical polymerization of polyacrylate-AuNPs' composites, with the purpose of using them for temporary cavity fillings in the dental industry. SEM characterisation of polyacrylate-AuNPs' composites revealed a uniform distribution of AuNPs through the polymer matrix, revealing that the AuNPs remained stable during the polymerization process. The density measurements revealed that colloidal AuNPs increase the densities of the prepared polyacrylate-AuNPs' composites; the densities were increased up to 40% in comparison with the densities of the control samples. A compressive test showed that polyacrylate-AuNPs' composites exhibited lower compressive strength compared to the control samples, while their toughness increased. At 50% compression deformation some of the samples fracture, suggesting that incorporation of colloidal AuNPs do not improve their compressive strength, but increase their toughness significantly. This increased toughness is the measured property which makes prepared polyacrylate-AuNPs potentially useful in dentistry.
Emulsions with high volume fraction of droplet phase were used to prepare macroporous polymers (polyHIPEs) of dimethylaminoethyl methacrylate (DMAEMA) and 2-hydroxyethyl methacrylate (HEMA) ...crosslinked with various amounts of ethylene glycol dimethacrylate (EGDMA) and N,N′-methylene bisacrylamide (MBAA), respectively. Monoliths with cellular interconnected porous structure were obtained. Up to 6 times of water (weight/weight) was absorbed by the materials while no apparent change in volume was found suggesting that the main mechanism of water absorption was primary pore filling. Prepared materials were used for the removal of dyes methylene blue (MB) and methyl orange (MO) from their aqueous solutions; in 120 min 6.5 mg g−1 of MB and 1.6 mg g−1 of MO were removed.
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•Highly crosslinked networks of hydrophilic methacrylates were prepared using high internal phase emulsions.•Monoliths were able to absorb water filling the cavities of the macroporous network while no monolith volume change appeared.•Materials were able to adsorb methylene blue and methyl orange from aqueous solutions quickly and efficiently.
We explore how the COVID-19 pandemic was associated with avoidance of, and challenges with, antenatal, childbirth and postpartum care among women in Kiambu and Nairobi counties, Kenya; and whether ...this was associated with a report of declined trust in the health system due to the pandemic. Women who delivered between March and November 2020 were invited to participate in a phone survey about their care experiences (n = 1122 respondents). We explored associations between reduced trust and care avoidance, delays and challenges with healthcare seeking, using logistic regression models adjusted for women's characteristics. Approximately half of respondents said their trust in the health care system had declined due to COVID-19 (52.7%, n = 591). Declined trust was associated with higher likelihood of reporting barriers accessing antenatal care (aOR 1.59 95% CI 1.24, 2.05), avoiding care for oneself (aOR 2.26 95% CI 1.59, 3.22) and for one's infant (aOR 1.77 95% CI 1.11, 2.83), and of feeling unsafe accessing care (aOR 1.52 95% CI 1.19, 1.93). Since March 2020, emergency services, routine care and immunizations were avoided most often. Primary reported reasons for avoiding care and challenges accessing care were financial barriers and problems accessing the facility. Declined trust in the health care system due to COVID-19 may have affected health care-seeking for women and their children in Kenya, which could have important implications for their health and well-being. Programs and policies should consider targeted special "catch-up" strategies that include trust-building messages and actions for women who deliver during emergencies like the COVID-19 pandemic.
•Novel theoretically-grounded data on routine vaccination during COVID-19 pandemic.•Under-vaccination was not common, but increased during COVID-19 pandemic.•Safety concerns were the only attitudinal ...factors associated with under-vaccination.•Those who trusted health workers had lower odds of missed vaccines.•Receiving person-centered vaccination services was the strongest determinant.
Although vaccination confidence is declining globally, there is little detailed information from low- and middle-income countries about factors influencing routine vaccination behavior in these contexts.
In mid-2022, we surveyed people who gave birth in Kenya between 2017–2022, and asked them about their children’s vaccination history and about hypothesized correlates of vaccination per the Behavioural and Social Drivers of Vaccination model.
Of 873 children in this sample, 117 (13%) were under-vaccinated (i.e., delayed or missing vaccine dose(s)) – and under-vaccination was more common among births during the COVID-19 pandemic (2020–2022) versus pre-pandemic (2017–2019). In multi-level multivariable models, children of respondents who expressed concerns about serious side effects from vaccines had significantly higher odds of missed vaccine dose(s) (aOR 2.06, 95 % CI 1.14–3.72), and there was a strong association between having more safety concerns now versus before the COVID-19 pandemic (aOR missed dose(s) 4.44, 95 % CI 1.71–11.51; aOR under-vaccination 3.03, 95 % CI 1.28–7.19). People with greater trust in health workers had lower odds of having a child with missed vaccine dose(s) (aOR 0.85, 95 % CI 0.75–0.97). People who reported higher patient-centered quality of vaccination care had much lower odds of having children with delayed or missed vaccine dose(s) (aOR missed dose(s) 0.14, 95 % CI 0.04–0.58; aOR under-vaccination 0.27, 95 % CI 0.10–0.79).
These findings highlight potential strategies to improve vaccine coverage: greater focus on patient-centered quality of care, training healthcare workers on how to address safety concerns about vaccines, and building trust in the health care system and in health workers.
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