The surface of fumed nano‐silica (nano‐SiO2) was treated with an alkyl silazane to change from hydrophilic surface to hydrophobic, and the surface of aluminum trihydroxide (nano‐ATH) was treated with ...a vinyl silazane to improve electrical properties (high voltage direct current HVDC breakdown strength and tracking resistance) in silicone nanocomposites. They were prepared by mixing liquid silicone resin with the modified nano‐SiO2 and the modified nano‐ATH, and the effects of the modified nano‐ATH particles on the electrical properties were studied in order to apply them to heavy electric equipment. The surface modifications were confirmed by thermogravimetric analysis and contact angle analysis. As the nano‐ATH content increased, (±)HVDC breakdown strength increased and tracking resistance was greatly improved. As the nano‐ATH content increased, the initial generation of leakage current was delayed, and the occurrence frequency and the intensity of the leakage current decreased. The erosion weight due to the tracking also decreased.
To develop silicone/nanosilica insulation materials for high voltage direct current (HVDC), hydrophilic surface of fumed nanosilica was changed to hydrophobic by modifying with various ratios of ...alkylsilane and alkylsilane/vinylsilane coupling agents and the effects of the modified nanosilicas on the HVDC breakdown strength under negative or positive polarities were studied. Dielectric and tensile properties were also studied. The surface modification was confirmed by Fourier‐transform infrared spectroscopy (FT‐IR) analysis and the weights of the alkyl and alkyl/vinyl groups on the modified nanosilicas were measured by thermogravimetric analysis (TGA). Silicone rubber nanocomposites were prepared by mixing a liquid silicone rubber (LSR) and the modified nanosilicas, in which the mixing ratio of the LSR to the nanosilicas was fixed to be 20 wt%. Transmission electron microscopy (TEM) was used to observe the even dispersion of the nanosilica particles in the LSR matrix, and it was found that the surface‐modified nanosilicas were well dispersed in the form of nano‐clusters with 20–60 nm in size. Electrical properties (±HVDC breakdown strength and dielectric properties) and mechanical properties (tensile strength and elongation‐at‐break) were estimated, and it was found that ±HVDC breakdown strength and tensile strength were maximal when the surface modification ratio of alkyl: alkyl/vinyl groups was 50: 50 wt%.
Hydrophilic surface of fumed nanosilica was treated with a trimethylsilane coupling agent to achieve its hydrophobic surface, and the surface modification was confirmed by thermogravimetric weight ...loss and increasing contact angle of water droplet. The effects of the surface-modified nanosilica content on the electrical and mechanical properties of epoxy nanocomposites were studied to apply to the insulators for heavy electrical equipment. Epoxy nanocomposites were prepared by mixing epoxy base resin/curing agent/accelerator/trimethylsilane-modified nanosilica in the weight ratio of 100:80:1:0-7 g. High-voltage direct current breakdown strength increased with increasing modified nanosilica content. High-voltage alternating current breakdown strength was maximum when the nanosilica content was 1 phr (part per one hundred of epoxy resin), and thereafter, the value gradually decreased as the nanosilica content increased. Tensile strength of epoxy nanocomposite with trimethylsilane-modified nanosilica (7 phr) is 78.76 MPa, which is 20% higher than that of neat epoxy resin. The dielectric permittivity increases with increasing amount of the trimethylsilane-modified nanosilica.
Background and Aims
Little is known about the association between non‐alcoholic fatty liver disease (NAFLD) and dementia. Given that hepatic steatosis is linked to abnormal fat metabolism, and fat ...dysregulation in the brain is related to dementia, we aimed to investigate whether NAFLD is associated with an increased risk of dementia.
Methods
We conducted a nationwide cohort study involving 4 031 948 subjects aged 40–69 years who underwent ≥2 health check‐ups provided by the National Health Insurance Service in Korea between January 2004 and December 2007. Based on the hepatic steatosis index (HSI), subjects were categorized into non‐NAFLD (HSI <30 at all check‐ups) and NAFLD (HSI >36 at one or more check‐ups). Dementia defined by ICD‐10 codes with prescription data was followed up until December 2017. Cox proportional hazards regression models analysed the dementia risk.
Results
At baseline, 31.3% had NAFLD. During the median follow‐up of 9.5 years, 138 424 in NAFLD group and 69 982 in non‐NAFLD group developed dementia. NAFLD group was associated with a higher risk of dementia than non‐NAFLD group on multivariable‐adjusted analysis (hazard ratio HR, 1.05; p < .001), competing risk analysis (HR, 1.08; p < .001) and propensity‐score matched analysis (HR, 1.09; p < .001). The association between NAFLD and dementia risk was more prominent among females (HR, 1.16; p < .001). The association was stronger among non‐obese NAFLD subjects (BMI <25 kg/m2, HR, 1.09; p < .001) than obese NAFLD subjects.
Conclusions
This nationwide study found that NAFLD is associated with an increased risk of dementia. The association was prominent among females and non‐obese NAFLD subjects.
Native extracellular matrix (ECM) can exhibit cyclic nanoscale stretching and shrinking of ligands to regulate complex cell–material interactions. Designing materials that allow cyclic control of ...changes in intrinsic ligand‐presenting nanostructures in situ can emulate ECM dynamicity to regulate cellular adhesion. Unprecedented remote control of rapid, cyclic, and mechanical stretching (“ON”) and shrinking (“OFF”) of cell‐adhesive RGD ligand‐presenting magnetic nanocoils on a material surface in five repeated cycles are reported, thereby independently increasing and decreasing ligand pitch in nanocoils, respectively, without modulating ligand‐presenting surface area per nanocoil. It is demonstrated that cyclic switching “ON” (ligand nanostretching) facilitates time‐regulated integrin ligation, focal adhesion, spreading, YAP/TAZ mechanosensing, and differentiation of viable stem cells, both in vitro and in vivo. Fluorescence resonance energy transfer (FRET) imaging reveals magnetic switching “ON” (stretching) and “OFF” (shrinking) of the nanocoils inside animals. Versatile tuning of physical dimensions and elements of nanocoils by regulating electrodeposition conditions is also demonstrated. The study sheds novel insight into designing materials with connected ligand nanostructures that exhibit nanocoil‐specific nano‐spaced declustering, which is ineffective in nanowires, to facilitate cell adhesion. This unprecedented, independent, remote, and cytocompatible control of ligand nanopitch is promising for regulating the mechanosensing‐mediated differentiation of stem cells in vivo.
Materials allowing unprecedented, remote, and cytocompatible control of in situ and time‐regulated nanoscale stretching and shrinking of ligand‐presenting magnetic nanocoils, that independently modulate the ligand pitch in the nanocoils, are presented. It is demonstrated that magnetic control of ligand nanostretching promotes cyclic adhesion and mechanotransduction of stem cells, both in vitro and in vivo, which facilitates their consequential differentiation.
A quantitative correlation between plasmon resonance and surface enhanced Raman scattering (SERS) signals is revealed by using a novel active plasmonic method, that is, a deformable nanoplasmonic ...membrane. A single SERS peak has the maximum gain at the corresponding plasmon resonance wavelength, which has the maximum extinction product of an excitation and the corresponding Raman scattering wavelengths.
The surface of micro-silica and nano-silica was modified with epoxy-modified silicone and their effect on the electrical breakdown strength was evaluated in epoxy/micro-/nano-silica composites ...(EMNCs). Firstly, the surface of micro- and nano-silica was treated with hydroxyl silane and then the hydroxyl group of the silane was reacted with epoxy-modified silicone. The surface-treated micro- and nano-silicas were mixed with epoxy resin and polyester-modified polydimethylsiloxane (PEM-PDMS) by using an ultrasonicator. Transmission electron microscope (TEM) was used to observe the even dispersion of nano-silica in an epoxy/micro-silica composite and it was found that the nano-silicas were well dispersed. The electrical breakdown strength of the epoxy/micro-silica (60 wt%)/nano-silica (1 phr)/PEM-PDMS (0.5 phr) system was 60.0 kV/2 mm, which was 13.6% higher than that of epoxy/micro-silica (60 wt%)/PEM-PDMS (0.5 phr) system, 52.8 kV/2 mm. The contact angle of neat epoxy was 77°, which was 132% higher than that of epoxy/micro-silica (60 wt%)/nano-silica (1 phr)/PEM-PDMS (0.5 phr) system, 101.6°.
Developing materials with the capability of changing their innate features can help to unravel direct interactions between cells and ligand‐displaying features. This study demonstrates the grafting ...of magnetic nanohelices displaying cell‐adhesive Arg‐Gly‐Asp (RGD) ligand partly to a material surface. These enable nanoscale control of rapid winding (“W”) and unwinding (“UW”) of their nongrafted portion, such as directional changes in nanohelix unwinding (lower, middle, and upper directions) by changing the position of a permanent magnet while keeping the ligand‐conjugated nanohelix surface area constant. The unwinding (“UW”) setting cytocompatibility facilitates direct integrin recruitment onto the ligand‐conjugated nanohelix to mediate the development of paxillin adhesion assemblies of macrophages that stimulate M2 polarization using glass and silicon substrates for in vitro and in vivo settings, respectively, at a single cell level. Real time and in vivo imaging are demonstrated that nanohelices exhibit reversible unwinding, winding, and unwinding settings, which modulate time‐resolved adhesion and polarization of macrophages. It is envisaged that this remote, reversible, and cytocompatible control can help to elucidate molecular‐level cell–material interactions that modulate regenerative/anti‐inflammatory immune responses to implants.
The use of ligand‐presenting nanohelices is reported that are partly grafted to a material surface to enable magnetic field‐controlled unwinding and winding of their nongrafted portion. It is demonstrated that the unwinding of ligand‐conjugated nanohelix facilitates direct integrin recruitment onto the ligand‐conjugated nanohelix on a single cell level to mediate paxillin adhesion assembly that stimulates M2 polarization of macrophages.
The objective of this study was to investigate current perception and expected price of personal sound amplification products (PSAPs) and to analyze influencing factors through multi-center ...hospital-based surveys of outpatients, caregivers, and hearing experts.
A multi-center exploratory cross-sectional study was conducted in two groups of respondents with two separate surveys: 1) a perception survey of patients and caregivers who visited an otorhinolaryngology outpatient clinic in 5 general hospitals and 2) an opinion survey of hearing specialists about the expected price of PSAPs. A total of 197 outpatient visitors responded to the perception survey, and 42 hearing specialists responded to the opinion survey.
Overall perception score (18 questions) was 3.04 (95% CI, 3.00-3.09). When 5 categories of perception (knowledge, needs, cost, expectation, and information categories) were analyzed, cost and expectation showed the highest scores of 3.33 (95% CI, 3.21-3.44) and 3.33 (95% CI, 3.27-3.40), respectively, and needs showed the lowest score of 2.23 (95% CI, 1.97-2.49). The ≥ 60-year-old group showed significantly higher perception of PSAPs (P = 0.002), and the individuals with greater severity of subjective hearing loss showed significantly higher perception of PSAPs (P = 0.002). The expected price of PSAPs of the outpatient visitors was 933.9 USD (95% CI, 811.9-1056.0) per ear. Mean expected price of PSAPs of hearing specialists was 291.3 USD (95% CI, 238.2-344.3) per ear.
The perception rate of PSAPs was very low, and there was a discrepancy in the expected price of PSAPs between patients/caregivers and hearing experts. Hearing specialists should make effort to improve perception of PSAPs.
Design of materials with remote switchability of the movement of decorated nanostructures presenting cell‐adhesive Arg‐Gly‐Asp ligand can decipher dynamic cell‐material interactions in decorated ...ligand nanostructures. In this study, the decoration of ligand‐bearing gold nanoparticles (ligand‐AuNPs) on the magnetic nanoparticle (MNP) with varying ligand‐AuNP densities is demonstrated, which are flexibly coupled to substrate in various MNP densities to maintain constant macroscopic ligand density. Magnetic switching of upward (“Upper Mag”) or downward (“Lower Mag”) movement of varying ligand‐AuNPs is shown via stretching and compression of the elastic linker, respectively. High ligand‐AuNP densities promote macrophage adhesion‐regulated M2 polarization that inhibits M1 polarization. Remote switching of downward movement (“Lower Mag”) of ligand‐AuNPs facilitates macrophage adhesion‐regulated M2 polarization, which is conversely suppressed by their upward movement (“Upper Mag”), both in vitro and in vivo. These findings are consistent with human primary macrophages. These results provide fundamental understanding into designing materials with decorated nanostructures in both high ligand‐AuNP density and downward movement of the ligand‐AuNPs toward the substrate to stimulate adhesion‐regulated M2 polarization of macrophages while suppressing pro‐inflammatory M1 polarization, thereby facilitating tissue‐healing responses.
The decoration of ligand‐bearing gold nanoparticles on the magnetic nanoparticle that are flexibly coupled to a substrate without varying macroscopic ligand density is demonstrated. It is shown that magnetic switching of elastic movement of varying ligand‐bearing gold nanoparticle densities regulates the adhesion‐mediated polarization of macrophages, both in vitro and in vivo.
