Internet Use, Risk Awareness, and Demographic Characteristics Associated With Engagement in Preventive Behaviors and Testing: Cross-Sectional Survey on COVID-19 in the United States.

BACKGROUND: During the coronavirus disease (COVID-19) pandemic, engagement in preventive behaviors and getting tested for the virus play a crucial role in protecting people from contracting the new coronavirus. OBJECTIVE: This study aims to examine how internet use, risk awareness, and demographic characteristics are associated with engagement in preventative behaviors and testing during the COVID-19 pandemic in the United States. METHODS: A cross-sectional survey was conducted on Amazon Mechanical Turk from April 10, 2020, to April 14, 2020. Participants' internet use (in terms of the extent of receiving information pertaining to COVID-19), risk awareness (whether any immediate family members, close friends or relatives, or people in local communities tested positive for COVID-19), demographics (sex, age, ethnicity, income, education level, marital status, and employment status), as well as their engagement in preventative behaviors and testing were assessed. RESULTS: Our data included 979 valid responses from the United States. Participants who received more COVID-19-related health information online reported more frequent effort to engage in all types of preventive behaviors: wearing a facemask in public (odds ratio [OR] 1.55, 95% CI 1.34-1.79, P<.001), washing hands (OR 1.58, 95% CI 1.35-1.85, P<.001), covering nose and mouth when sneezing and coughing (OR 1.78, 95% CI 1.52-2.10, P<.001), keeping social distance with others (OR 1.41, 95% CI 1.21-1.65, P<.001), staying home (OR 1.40, 95% CI 1.20-1.62, P<.001), avoiding using public transportation (OR 1.57, 95% CI 1.32-1.88, P<.001), and cleaning frequently used surfaces (OR 1.55, 95% CI 1.34-1.79, P<.001). Compared with participants who did not have positive cases in their social circles, those who had immediate family members (OR 1.48, 95% CI 8.28-26.44, P<.001) or close friends and relatives (OR 2.52, 95% CI 1.58-4.03, P<.001) who tested positive were more likely to get tested. Participants' sex, age, ethnicity, marital status, and employment status were also associated with preventive behaviors and testing. CONCLUSIONS: Our findings revealed that the extent of receiving COVID-19-related information online, risk awareness, and demographic characteristics including sex, ethnicity, age, marital status, and employment status are key factors associated with US residents' engagement in various preventive behaviors and testing for COVID-19.

Tooth loss as a risk factor for dementia: systematic review and meta-analysis of 21 observational studies.

BACKGROUND: Tooth loss is suggested to be associated with an increased risk of dementia in many studies. But the relationship between tooth loss and dementia is not yet fully understood. This systematic review and meta-analysis aimed to determine the relative effect of tooth loss on dementia risk. METHODS: An electronic search of PubMed, Scopus, Embase, and Web of Knowledge was conducted in March 2018 to identify relevant observational studies with the English language restriction. Studies were included if they assessed the relationship between tooth loss and risk of dementia. Study quality was detected by the modified Downs and Black scale. Odds risks (ORs) were pooled using a random-effects model in the crude model. RESULTS: The literature search initially yielded 1574 articles, and 21 observational studies published between 1994 and 2017 were finally included for the analyses. The crude results with random-effects model showed that patients with multiple tooth loss had higher incidence of dementia (OR 2.62, 95% CI 1.90-3.61, P < 0.001, I2 = 90.40%). The association remained noted when only adjusted results were pooled from 18 studies (OR 1.55, 95% CI 1.41-1.70, P = 0.13, I2 = 28.00%). Meta-regression analysis showed that study design explained about 16.52% of heterogeneity in the crude model. The overall quality rating scores of studies ranged from 11 to 16. CONCLUSIONS: Findings from this review evidenced that tooth loss is positively associated with an increased risk of dementia in adults. Future well-designed longitudinal researches examining the direct and indirect relationship between tooth loss and dementia risk are encouraged.

Fractal structures of the hydrogels formed in situ from poly(N-isopropylacrylamide) microgel dispersions.

Dispersions of poly(N-isopropylacrylamide) (PNIPAM) microgel thermally gel in the presence of inorganic salts. The in situ-formed hydrogels, with a network of soft particles, represent a new type of colloidal gels. Here, their fractal structures were determined by rheological measurements, using the models of both Shih et al. and Wu and Morbidelli. According to the definition of Shih et al., the colloidal PNIPAM gels fall into the strong-link regime. Yet the calculated fractal dimension of the floc backbone, x, yielded unrealistic negative values, suggesting this model is inapplicable for the present system. The Wu-Morbidelli model gives physically sounder results. According to this model, the strengths of the inter- and intrafloc links are comparable, and the in situ-formed gels are in the transition regime. The fractal dimension, d(f), of the hydrogel decreases from ∼2.5 to ∼1.8 when the heating temperature increases from 34 to 40 °C. The d(f) values suggest different aggregation mechanisms at different temperatures, that is, a reaction-limited one accompanied by rearrangement at low temperature, a typical reaction-limited one at the intermediate temperature, and a diffusion-limited one at high temperature. With increasing salt concentration, the d(f) of the hydrogel decreases from ∼2.1 to ∼1.7, suggesting the aggregation mechanism changes from reaction-limited to diffusion-limited. The effects of both temperature and salt concentration can be explained by the changes in the interactions among the microgel particles. The thermogellable PNIPAM microgel dispersions may serve as a model system for the study of heat-induced gelation of globular proteins.

Curcumin-loaded PLGA-PEG nanoparticles conjugated with B6 peptide for potential use in Alzheimer's disease.

Alzheimer's disease is a neurodegenerative disorder mainly characterized by ß-amyloid deposit and tau hyperphosphorylation with no curative treatments. Curcumin (Cur) has been proved to have potential use in Alzheimer's disease with its anti-amyloid, anti-inflammatory, and anti-oxidant properties, etc. However, its hydrophobicity and low bioavailability hinder its application. In this paper, we designed a novel brain-target nanoparticle, poly(lactide-co-glycolide)-block-poly(ethylene glycol) (PLGA-PEG) conjugated with B6 peptide and was loaded with Cur (PLGA-PEG-B6/Cur) and administered it into HT22 cells and APP/PS1 Al transgenic mice. The in vitro assays including dynamic light scattering (DLS), flow cytometry (FCM), red blood cell (RBC) lysis, and thromboelastography (TEG) analysis indicated that this nanoparticle could narrow the diameter of Cur, increase its cellular uptake and possess good blood compatibility. The results from Morris water maze proved that PLGA-PEG-B6/Cur could tremendously improve the spatial learning and memory capability of APP/PS1 mice, compared with native Cur. The ex vivo assays including Bielschowsky silver staining, immunostaining, and western blotting demonstrated that PLGA-PEG-B6/Cur could reduce hippocampal ß-amyloid formation and deposit and tau hyperphosphorylation. Thus, we suggested that PLGA-PEG-B6/Cur nanoparticles would be of potential and promising use for the treatment of Alzheimer's disease.