Revealing molecular-level surface redox sites of controllably oxidized black phosphorus nanosheets.

Bulk and two-dimensional black phosphorus are considered to be promising battery materials due to their high theoretical capacities of 2,600 mAh g-1. However, their rate and cycling capabilities are limited by the intrinsic (de-)alloying mechanism. Here, we demonstrate a unique surface redox molecular-level mechanism of P sites on oxidized black phosphorus nanosheets that are strongly coupled with graphene via strong interlayer bonding. These redox-active sites of the oxidized black phosphorus are confined at the amorphorized heterointerface, revealing truly reversible pseudocapacitance (99% of total stored charge at 2,000 mV s-1). Moreover, oxidized black-phosphorus-based electrodes exhibit a capacitance of 478 F g-1 (four times greater than black phosphorus) with a rate capability of ~72% (compared to 21.2% for black phosphorus) and retention of ~91% over 50,000 cycles. In situ spectroelectrochemical and theoretical analyses reveal a reversible change in the surface electronic structure and chemical environment of the surface-exposed P redox sites.

Nuclear localization and functional characteristics of voltage-gated potassium channel Kv1.3.

It is widely known that ion channels are expressed in the plasma membrane. However, a few studies have suggested that several ion channels including voltage-gated K(+) (Kv) channels also exist in intracellular organelles where they are involved in the biochemical events associated with cell signaling. In the present study, Western blot analysis using fractionated protein clearly indicates that Kv1.3 channels are expressed in the nuclei of MCF7, A549, and SNU-484 cancer cells and human brain tissues. In addition, Kv1.3 is located in the plasma membrane and the nucleus of Jurkat T cells. Nuclear membrane hyperpolarization after treatment with margatoxin (MgTX), a specific blocker of Kv1.3 channels, provides evidence for functional channels at the nuclear membrane of A549 cells. MgTX-induced hyperpolarization is abolished in the nuclei of Kv1.3 silenced cells, and the effects of MgTX are dependent on the magnitude of the K(+) gradient across the nuclear membrane. Selective Kv1.3 blockers induce the phosphorylation of cAMP response element-binding protein (CREB) and c-Fos activation. Moreover, Kv1.3 is shown to form a complex with the upstream binding factor 1 in the nucleus. Chromatin immunoprecipitation assay reveals that Sp1 transcription factor is directly bound to the promoter region of the Kv1.3 gene, and the Sp1 regulates Kv1.3 expression in the nucleus of A549 cells. These results demonstrate that Kv1.3 channels are primarily localized in the nucleus of several types of cancer cells and human brain tissues where they are capable of regulating nuclear membrane potential and activation of transcription factors, such as phosphorylated CREB and c-Fos.

The Role of KV7.3 in Regulating Osteoblast Maturation and Mineralization.

KCNQ (KV7) channels are voltage-gated potassium (KV) channels, and the function of KV7 channels in muscles, neurons, and sensory cells is well established. We confirmed that overall blockade of KV channels with tetraethylammonium augmented the mineralization of bone-marrow-derived human mesenchymal stem cells during osteogenic differentiation, and we determined that KV7.3 was expressed in MG-63 and Saos-2 cells at the mRNA and protein levels. In addition, functional KV7 currents were detected in MG-63 cells. Inhibition of KV7.3 by linopirdine or XE991 increased the matrix mineralization during osteoblast differentiation. This was confirmed by alkaline phosphatase, osteocalcin, and osterix in MG-63 cells, whereas the expression of Runx2 showed no significant change. The extracellular glutamate secreted by osteoblasts was also measured to investigate its effect on MG-63 osteoblast differentiation. Blockade of KV7.3 promoted the release of glutamate via the phosphorylation of extracellular signal-regulated kinase 1/2-mediated upregulation of synapsin, and induced the deposition of type 1 collagen. However, activation of KV7.3 by flupirtine did not produce notable changes in matrix mineralization during osteoblast differentiation. These results suggest that KV7.3 could be a novel regulator in osteoblast differentiation.

Prevalence and associated factors of tinnitus: data from the Korean National Health and Nutrition Examination Survey 2009-2011.

BACKGROUND: Tinnitus is a common condition and frequently can be annoying to affected individuals. We investigated the prevalence and associated factors for tinnitus in South Korea using the data from the Korea National Health and Nutrition Examination Surveys (KNHANES) during 2009-2011. METHODS: KNHANES is a cross-sectional survey of the civilian, non-institutionalized population of South Korea (n = 21 893). A field survey team that included an otolaryngologist moved with a mobile examination unit and performed interviews and physical examinations. RESULTS: Among the population over 12 years of age, the prevalence of any tinnitus was 19.7% (95% CI 18.8%-20.6%). Tinnitus was more prevalent in women, and the prevalence rate increased with age (P < 0.001). Among those with any tinnitus, 29.3% (95% CI 27.3%-31.3%) experienced annoying tinnitus that affected daily life. Annoying tinnitus also increased with age (P < 0.001), but no sex difference was demonstrated (P = 0.25). In participants aged 40 years or older, age, quality of life, depressive mood, hearing loss, feeling of dizziness, and rhinitis were associated with any tinnitus (P < 0.05). Age, hearing loss, history of cardiovascular disease, and stress were associated with annoying tinnitus (P < 0.05). CONCLUSIONS: Tinnitus is a common condition, and a large population suffers from annoying tinnitus in South Korea. Public understanding of associated factors might contribute to better management of tinnitus.

Trends in food and nutrient intake over 20 years: findings from the 1998-2018 Korea National Health and Nutrition Examination Survey.

OBJECTIVES: We aimed to examine the current status and trends of food and nutrient intake in the Korean population over the past 20 years using the data from the Korea National Health and Nutrition Examination Survey (KNHANES). METHODS: We conducted a survey of 116,284 subjects over the age of one year in Korea, who participated in the KNHANES between 1998 and 2018. We collected data on the subjects' intake for the day before using the 24-hour recall method. The annual percent change (APC) in the food groups and nutrient intake were calculated using SAS and Joinpoint software. RESULTS: The intake of grains (APC=-0.4, p<0.05) and vegetables (APC=-0.8, p<0.05) was observed to decrease. In contrast, the intake of beverages, meat, dairy, and eggs increased. In particular, beverage intake increased by more than four times (APC=9.2, p<0.05). There was no significant change in energy intake. However, the proportion of energy intake from carbohydrates decreased by approximately 5%p (APC=-0.3, p<0.05), whereas that from fat increased by approximately 5%p (APC= 1.1, p<0.05). Additionally, there were decreases in the proportion of energy intake from breakfast and homemade meals and increases in the energy intake from snacks, dining out, and convenience food. The intake of vitamin C (APC=-3.2, p<0.05) and sodium (APC=-2.3, p<0.05) significantly decreased. CONCLUSIONS: Over the past 20 years, there has been decreases in the intake of grains, vegetables, carbohydrates, sodium, and vitamin C and increases in the intake of beverages, dairy, meat, eggs, and fat. Since nutritional status is an important factor in the prevention and management of chronic diseases, it should be continuously monitored.

The prevalence of preauricular sinus and associated factors in a nationwide population-based survey of South Korea.

OBJECTIVE: To investigate the prevalence of preauricular sinus (PAS) using data from a government-centered survey in South Korea and to reveal the relationship between the occurrence of PAS and associated factors. PATIENTS: Data obtained during July 2008 to December 2012 were analyzed. Annually, 10,000 to 12,000 individuals are selected from a panel to represent the population using a multistage clustered and stratified random sampling method based on the National Census Data. A total of 56,592 individuals participated in the survey (25,586 male and 31,006 female). INTERVENTION: After completion of the otolaryngologic questionnaires, the auricle was examined to check for malformation and PAS in those older than 1 year. Next, an otolaryngologist conducted a physical examination of the head and neck using videoassisted endoscopy. MAIN OUTCOME MEASURE: Physical examination. RESULTS: One thousand one hundred thirty-two individuals had PAS representing the overall prevalence of 1.91% in South Korea, with 79.08% of cases occurring unilaterally. Female participants had a significantly higher prevalence than male (p < 0.001), and a significant decrease with age was observed in both male and female populations (p < 0.001). A higher proportion of PAS was found in individuals with external ear anomaly (p < 0.001) and not associated with abnormal otoendoscopic findings such as tympanic membrane perforation, cholesteatomatous condition including retraction pocket, and middle ear effusion. CONCLUSION: A large-scale government-centered survey demonstrates a high prevalence, female dominance, and age-related decrease of PAS in South Korea.

Prevalence of eye diseases in South Korea: data from the Korea National Health and Nutrition Examination Survey 2008-2009.

PURPOSE: The aim of this study is to report on preliminary data regarding the prevalence of major eye diseases in Korea. METHODS: We obtained data from the Korea National Health and Nutrition Examination Survey, a nation-wide cross-sectional survey and examinations of the non-institutionalized civilian population in South Korea (n = 14,606), conducted from July 2008 to December 2009. Field survey teams included an ophthalmologist, nurses, and interviewers, traveled with a mobile examination unit and performed interviews and ophthalmologic examinations. RESULTS: The prevalence of visual impairment, myopia, hyperopia and astigmatism in participants over 5 years of age was 0.4 ± 0.1%, 53.7 ± 0.6%, 10.7 ± 0.4%, and 58.0 ± 0.6%, respectively. The prevalence of strabismus and blepharoptosis in participants over 3 years of age was 1.5 ± 0.1% and 11.0 ± 0.8%, respectively. In participants over 40 years of age, the prevalence of cataract, pterygium, early and late age-related macular degeneration, diabetic retinopathy and glaucoma was 40.2 ± 1.3%, 8.9 ± 0.5%, 5.1 ± 0.3%, 0.5 ± 0.1%, 13.4 ± 1.5%, and 2.1 ± 0.2%, respectively. CONCLUSIONS: This is the first nation-wide epidemiologic study conducted in South Korea for assessment of the prevalence of eye diseases by both the Korean Ophthalmologic Society and the Korea Center for Disease Control and Prevention. This study will provide preliminary information for use in further investigation, prevention, and management of eye diseases in Korea.