A dynamic contact mode operation of electrostatic-force microscopy ͑EFM͒ with an ac modulation has been developed and used to investigate the domain strucutre and dynamics of a triglycine sulfate single crystal. Well-separated topographic and domain contrast images have been obtained by detecting the force instead of the force gradient in the dynamic contact mode operation of EFM. Surface charge density and the anisotropic domain wall thickness have been measured. The evolution of domains embedded in an oppositely polarized larger domain indicates the existence of a significant interaction between domains of the same polarity.

There are few studies that have used audiometric testing to gauge the demographic characteristics and associated risk factors for hearing loss at the national-level. Here, we investigated the weighted prevalence and associated factors of hearing impairment in 16,040 Korean adult population. Subjects completed audiometric test and laboratory examination as part of the data from The 2010–2012 Korea National Health and Nutrition Examination Survey (KNHANES). In our respective study, the overall weighted (n = 33,762,584) prevalence of mild hearing impairment among the Korean adult population was 20.5% (95% clearance [CI], 19.6–21.6), whereas moderate-to-profound hearing impairment was 9.2% (95% CI, 8.6–9.9). The weighted prevalence of mild hearing impairment in younger adults (19–39 years’ old) was 4.4% (3.5–5.5), in middle-age adults (40–64 years), it was 21.1% (19.8–22.5), and in older adults (≥65 years’ old), it was 69.7% (67.8–71.6). Logistic regression analyses were performed for low/mid frequency or high-frequency mild hearing impairment with age, sex, tobacco use, heavy alcohol use, educational background, occupational noise exposure, obesity, hypertension, diabetes, total serum cholesterol, and estimated glomerular filtration rate (eGFR) <60 mL/min/1.73m2 as covariates. The analyses revealed independent correlations between increased age, tobacco use, education, hypertension, and eGFR <60 mL/min/1.73m2, and low/mid frequency and high frequency mild hearing impairment. High frequency mild hearing impairment was positively correlated with male sex, diabetes, and an increase in total serum cholesterol. Taken together, hearing impairment in Korea is highly prevalent with approximately one-fifth of Korean adult reporting mild hearing impairment. This study suggests that individuals with cardiovascular risk factors such as hypertension, diabetes, smoking, increased serum cholesterol, or decreased eGFR are at particular risk of developing hearing impairment. As such, these groups may benefit from hearing loss screening in addition to those groups typically considered to be of elevated risk including geriatrics, those of low socioeconomic status, and those with considerable occupational noise exposure.

Dynamic contact mode electrostatic force microscopy ͑DC-EFM͒ was developed as a new operation mode of scanning probe microscope ͑SPM͒. By operating EFM in a contact mode with an ac modulation bias, we have improved the spatial resolution and also achieved a complete separation of the topographic effect from other electrostatic force effect overcoming the mixing problem of a topographic effect with other electrostatic effects frequently encountered in the conventional noncontact EFM measurement. DC-EFM can be utilized either as a force microscopy for the surface hardness, or as a potentiometry for the surface potential distribution, or as a charge densitometry for the surface charge density study. This is also applicable to the measurement and control of the domain structure in ferroelectric materials that have a bound surface charge.

Early menarche is strongly associated with adulthood obesity; however, the relationship between age at menarche and cardiovascular disease (CVD) in Korean women remains poorly understood. Here, we investigated the association between early menarche and risk factors for developing CVD during adulthood using a nationwide population database.In total, 12,336 women (weighted n = 17,483,406; weighted age, 45.7 years) who participated in the Korean National Health and Nutrition Examination Survey 2010 to 2013 were included in this study. Participants were scored using the National Cholesterol Education Program Adult Treatment Panel III criteria for metabolic syndrome. Risk of CVD was estimated using the 10-year Framingham Coronary Heart Disease Risk Point Scale (10-year FRS).Early menarche (≤11 years) was reported in 5.2% (weighted n = 917,493) of subjects. The weighted prevalences of metabolic syndrome and ≥20% 10-year FRS were 23.6% [95% confidence interval (95% CI), 22.7–24.6] and 7.7% (7.1–8.3), respectively. Women with early menarche reported a significantly higher body mass index and waist circumference, along with a higher prevalence of hypertension, diabetes, and metabolic syndrome than those with later menarche (≥13 years). Furthermore, the prevalence of women with a ≥10% or ≥20% 10-year FRS was higher in those with early menarche than in other groups after adjusting for age, smoking, education level, and menstruation. Logistic regression analyses controlling for these and other confounding factors revealed odds ratios of 2.29 (95% CI = 1.25–4.19) and 1.78 (0.96–3.30) for ≥10% and ≥20% 10-year FRS in women with early menarche, respectively, compared with those in the latest menarche group (≥17 years).Taken together, this nationwide study revealed that women with early menarche are at increased risks of metabolic syndrome and CVD. Early menarche may therefore represent an important marker for early preventive interventions.