J Med Internet Res
October 2024
Background: To safeguard the most vulnerable individuals during the COVID-19 pandemic, numerous governments enforced measures such as stay-at-home orders, social distancing, and self-isolation. These social restrictions had a particularly negative effect on older adults, as they are more vulnerable and experience increased loneliness, which has various adverse effects, including increasing the risk of mental health problems and mortality. Chatbots can potentially reduce loneliness and provide companionship during a pandemic.
View Article and Find Full Text PDFInt J Environ Res Public Health
November 2020
Background: Results of studies regarding the potential link between acid suppressant use and dementia risk are inconsistent. This study aimed to evaluate the association of cumulative exposure to histamine 2 receptor antagonists (H2RAs) and proton pump inhibitors (PPIs) with dementia risk in an Asian older cohort aged ≥65 years.
Methods: Patients initiating H2RA (the H2RA user cohort, = 21,449) or PPI (the PPI user cohort, = 6584) and those without prescription for H2RA (the H2RA non-user cohort, = 21,449) or PPI (the PPI non-user cohort, = 6584) between 1 January 2000 and 31 December 2005 without a prior history of dementia were identified from Taiwan's National Health Insurance Research Database (NHIRD).
Silicon-containing block copolymer thin films with high interaction parameter and etch contrast are ideal candidates to generate robust nanotemplates for advanced nanofabrication, but they typically form in-plane oriented microdomains as a result of the dissimilar surface energies of the blocks. Here, we describe a two-step annealing method to produce vertically aligned lamellar structures in thin film of a silicon-containing rod-coil thermotropic liquid crystalline block copolymer. The rod-coil block copolymer with the volume fraction of the Si-containing block of 0.
View Article and Find Full Text PDFA robust and transparent silica-like coating that imparts superhydrophobicity to a surface through its hierarchical multilevel self-assembled structure is demonstrated. This approach involves iterative steps of spin-coating, annealing, and etching of polystyrene-block-polydimethylsiloxane block copolymer thin films to form a tailored multilayer nanoscale topographic pattern with a water contact angle up to 155°. A model based on the hierarchical topography is developed to calculate the wetting angle and optimize the superhydrophobicity, in agreement with the experimental trends, and explaining superhydrophobicity arising through the combination of roughness at different lengthscales.
View Article and Find Full Text PDFThe self-assembly of a high-χ silicon-containing side-chain liquid crystalline block copolymer (LC BCP) in bulk and in thin films is reported, and the structural transition process from the hexagonally packed cylinder (HEX) to the body-centered cubic structure (BCC) in thin films was examined by both reciprocal and real space experimental methods. The block copolymer, poly(dimethylsiloxane-b-11-(4'-cyanobiphenyl-4-yloxy)undecylmethacrylate) (PDMS-b-P(4CNB11C)MA) with a molecular weight of 19.5 kg mol-1 and a volume fraction of PDMS 27% self-assembled in bulk into a hierarchical nanostructure of sub-20 nm HEX cylinders of PDMS with the P(4CNB11C)MA block exhibiting a smectic LC phase with a 1.
View Article and Find Full Text PDFThe self-assembly of block copolymers (BCPs) with novel architectures offers tremendous opportunities in nanoscale patterning and fabrication. Here, the thin film morphology, annealing kinetics, and topographical templating of an unconventional Janus-type "PS- branch-PDMS" bottlebrush copolymer (BBCP) are described. In the Janus-type BBCP, each segment of the bottlebrush backbone connects two immiscible side chain blocks.
View Article and Find Full Text PDFA combined experimental and self-consistent-field theoretical (SCFT) investigation of the phase behavior of poly(stryrene- b-dimethylsiloxane- b-styrene) (PS- b-PDMS- b-PS, or SDS32) thin films during solvent vapor annealing is presented. The morphology of the triblock copolymer is described as a function of the as-cast film thickness and the ratio of two different solvent vapors, toluene and heptane. SDS32 formed terraced bilayer morphologies even when the film thickness was much lower than the commensurate thickness.
View Article and Find Full Text PDFChronic kidney disease (CKD) has attracted considerable attention in the public health domain in recent years. Researchers have exerted considerable effort in attempting to identify critical factors that may affect the deterioration of CKD. In clinical practice, the physical conditions of CKD patients are regularly recorded.
View Article and Find Full Text PDFThe self-assembly of block copolymers with large feature sizes is inherently challenging as the large kinetic barrier arising from chain entanglement of high molecular weight (MW) polymers limits the extent over which long-range ordered microdomains can be achieved. Here, we illustrate the evolution of thin film morphology from a diblock copolymer of polystyrene-block-poly(dimethylsiloxane) exhibiting total number average MW of 123 kg mol, and demonstrate the formation of layers of well-ordered cylindrical microdomains under appropriate conditions of binary solvent mix ratio, commensurate film thickness, and solvent vapor annealing time. Directed self-assembly of the block copolymer within lithographically patterned trenches occurs with alignment of cylinders parallel to the sidewalls.
View Article and Find Full Text PDFThe response of polystyrene-block-poly(dimethylsiloxane) (PS-b-PDMS) thin films to UV exposure during solvent vapor annealing is described, in order to improve their applicability in nanolithography and nanofabrication. Two BCPs were examined, one with the PS block as majority (f = 68%, M = 53 kg mol), the other with PDMS block as majority (f = 67%, M = 44 kg mol). A 5 min UV irradiation was applied during solvent vapor annealing which led to both partial crosslinking of the polymer and a small increase in the temperature of the annealing chamber.
View Article and Find Full Text PDFWe report the synthesis of Janus bottlebrush block copolymers by graft-through polymerization of branched diblock macromonomers. Self-assembly of the bottlebrushes was characterized by small-angle X-ray scattering, atomic force microscopy, and scanning electron microscopy. Phase separation and packing models of the bottlebrushes were computed, and their self-assembly behavior was corroborated experimentally in bulk and in thin films.
View Article and Find Full Text PDFA combined thermal and solvent vapor annealing process for block copolymer self-assembly is demonstrated. Films of cylinder-forming poly(styrene--dimethylsiloxane) (SD45, 45.5 kg/mol, f = 31%) were preheated for 2 min above the glass transition temperature of both blocks, followed by immediate introduction into a chamber containing room temperature saturated vapors of toluene and -heptane.
View Article and Find Full Text PDFExtraskeletal osteoclast-like giant cell (OGC) tumors are uncommon and have mainly been found in the breast and pancreas. OGC neoplasms of the urinary tract are extremely rare, and their histogenesis and biologic behavior remain controversial. Gross hematuria is the most common presenting symptom, as in transitional cell carcinoma.
View Article and Find Full Text PDFBackground: Interstitial (cornual) pregnancy is a rare and life-threatening disease. Although systemic treatment with methotrexate (MTX) in an unruptured interstitial pregnancy has been used to preserve the entirety of the uterus, surgery is often used as a rescue method in failed cases. Use of an ultrasound-guided local injection can be a good alternative to surgery.
View Article and Find Full Text PDFWe present a case of twin reversed arterial perfusion syndrome complicated by an acardius acephalus fetus and complex skeletal dysplasia in the co-twin, including a reduction of the right arm and absence of the right scapula and 4 ribs, as evaluated with three-dimensional sonography and MRI.
View Article and Find Full Text PDFThe effect of lead (Pb) treatment on the soil microbial activities (soil microbial biomass and soil basal respiration) and rice physiological indices were studied by greenhouse pot experiment. Pb was applied as lead acetate at six different levels in two different paddy soils, namely 0 (control), 100, 300, 500, 700, 900 mg kg-1 soil. The results showed that the application of Pb at lower level (<300 mg kg-1) as lead acetate resulted in a slight increase in soil microbial activities compared with the control, and had an inhibitory influence at high concentration (>500 mg Pb kg-1 soil), which might be the critical concentration of Pb causing a significant decline in the soil microbial activities.
View Article and Find Full Text PDFThe microbial biomass, basal respiration and substrate utilization pattern in copper mining wasteland of red soil area, southern China, were investigated. The results indicated that soil microflora were obviously different compared with that of the non-mine soil. Microbial biomass and basal respiration were negatively affected by the elevated heavy metal levels.
View Article and Find Full Text PDFSome enzymatic activities were determined in the areas polluted by tailings from Tiantai Pb-Zn-Ag Mine in Zhejiang Province of China. The results indicated the soil enzymatic activities decreased significantly with increase of concentrations of heavy metals or the distance away from mining tailing center, especially dehydrogenase and urease activities. Multivariate regression analysis between heavy metal contents and soil enzymatic activities indicated that single dehydrogenase activity was very significantly correlated to combined effect of soil heavy metals in mine area.
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