Although the cardiovascular benefits of an increased urinary potassium excretion have been suggested, little is known about the potential cardiac association of urinary potassium excretion in patients with chronic kidney disease (CKD). In addition, whether the cardiac association of urinary potassium excretion was mediated by serum potassium levels has not been studied yet. We reviewed the data of 1,633 patients from a large-scale multicenter prospective Korean study (2011–2016). Spot urinary potassium to creatinine ratio was used as a surrogate for urinary potassium excretion. Cardiac injury was defined as a highly sensitive troponin T (hs-TnT) ≥ 14 ng/L. Odds ratios (ORs) and 95% confidence intervals (CIs) for cardiac injury were calculated using logistic regression analyses. Of 1,633 patients, the mean spot urinary potassium to creatinine ratio was 49.5 ± 22.6 mmol/g Cr and the overall prevalence of cardiac injury was 33.9%. Although serum potassium levels were not associated with cardiac injury, per 10 mmol/g Cr increase in the spot urinary potassium to creatinine ratio was associated with decreased odds of cardiac injury: OR (95% CI) of 0.917 95% CI (0.841-0.998, P= 0.047) in multivariate logistic regression analysis. In mediation analysis, approximately 6.4% of the relationship between spot urinary potassium to creatinine ratio and cardiac injury was mediated by serum potassium levels, which was not statistically significant (P = 0.368). Higher urinary potassium excretion was associated with lower odds of cardiac injury, which was not mediated by serum potassium levels.

Radiocarbon (14C) in natural samples undergoes changes due to variations in atmospheric CO2 resulting from anthropogenic activities. To analyze the variation of the 14C ratio in atmospheric CO2, deciduous tree leaves were collected in Gyeongju, a popular tourist city in South Korea. Leaf samples were collected from Prunus subg. Cerasus trees at five different sampling points throughout the city over 3 years (2018, 2020, and 2021). The 14C data of the samples were categorized into three groups (downtown, rural, and tourist sites) and analyzed for variations among the different years. The 14C ratio at downtown sites was stable after 2018, the rural site ratio increased between 2018 and 2020 and then decreased between 2020 and 2021, and the tourist site ratio increased after 2018. We theorize that the increased 14C ratio at the tourist site was caused by a decrease in tourism after 2018.

Severe heat exposure causes mitochondrial fragmentation and dysfunction, which contribute to the pathogenesis of heat-related illness. l-Citrulline is a naturally occurring amino acid and has been suggested to influence heat shock responses. This study aimed to test whether l-citrulline supplementation would preserve mitochondrial integrity and attenuate heat-induced skeletal muscle injury and elucidate the underlying mechanisms. At 37°C, l-citrulline (2 mM) increased mitochondrial elongation in mouse C2C12 myoblasts, a process associated with a reduction in mitochondrial fission protein Drp1 levels. Mechanistic studies revealed that l-citrulline increased cellular nitric oxide (NO) levels, but not S-nitrosylation of Drp1. l-Citrulline caused a decrease in phosphorylation of Drp1 at Ser 616 and an increase in phosphorylation of Drp1 at Ser 637, which resulted in a reduced mitochondrial localisation of Drp1. L-NAME, a non-selective NO synthase inhibitor, abolished the increase in l-citrulline-induced NO levels and inhibited Drp1 phosphorylation changes and mitochondrial elongation, which indicates the involvement of a NO-dependent pathway. Under 43°C heat stress conditions, l-citrulline prevented translocation of Drp1 to mitochondria, mitochondrial fragmentation and decreased membrane potential. Finally, l-citrulline pretreatment inhibited heat-induced reactive oxygen species overproduction, caspase 3/7 activation, apoptotic cell death and improved cell viability. NO inhibitor l-NAME abolished all the above protective effects of l-citrulline under heat stress. Our results suggest that l-citrulline prevents heat-induced mitochondrial dysfunction and cell injury through NO-mediated Drp1 inhibition in C2C12 myoblasts. l-Citrulline may be an effective treatment for heat-related illnesses and other mitochondrial diseases.

To explore sea level transgression in low-lying inland areas and its possible influence on prehistoric cultures, we investigated the physical and geochemical features of 20-m-long sedimentary cores from the previously seawater-filled Daesan Basin located in the middle reach of the present Nakdong River in Korea as proxies for seawater transgression deep inland areas due to Holocene sea level rise. Based on the relationships among grain size, total sulfur content (TS%), and carbon/sulfur (C/S) ratio, the first transgressive event was detected at ca. 8500 cal yr BP, caused by seawater influx along the present Nakdong River. Higher TS% (0.8–1%) and interbedded fossil oysters at 8000–6000 cal yr BP indicate marine environments, supporting a paleo-Daesan Bay with water depth of ~10–8 m. The common peaks in TS%, in both inland paleo-Daesan Bay and a present coastal area (Suncheon Bay) in southern Korea (e.g., at 3200 and 4700 cal yr BP), may indicate intervals of higher salinity, which suggests simultaneous responses to changes in sea level or hydroclimate. The duration of marine environment (paleo-Daesan Bay) in the remote inland from ca. 8000–3200 cal yr BP provides an analog for inland paleo-bay studies in East Asia.

Nosocomial transmission of COVID-19 among immunocompromised hosts can have a serious impact on COVID-19 severity, underlying disease progression and SARS-CoV-2 transmission to other patients and healthcare workers within hospitals. We experienced a nosocomial outbreak of COVID-19 in the setting of a daycare unit for paediatric and young adult cancer patients. Between 9 and 18 November 2020, 473 individuals (181 patients, 247 caregivers/siblings and 45 staff members) were exposed to the index case, who was a nursing staff. Among them, three patients and four caregivers were infected. Two 5-year-old cancer patients with COVID-19 were not severely ill, but a 25-year-old cancer patient showed prolonged shedding of SARS-CoV-2 RNA for at least 12 weeks, which probably infected his mother at home approximately 7–8 weeks after the initial diagnosis. Except for this case, no secondary transmission was observed from the confirmed cases in either the hospital or the community. To conclude, in the day care setting of immunocompromised children and young adults, the rate of in-hospital transmission of SARS-CoV-2 was 1.6% when applying the stringent policy of infection prevention and control, including universal mask application and rapid and extensive contact investigation. Severely immunocompromised children/young adults with COVID-19 would have to be carefully managed after the mandatory isolation period while keeping the possibility of prolonged shedding of live virus in mind.

We examine the physical conditions required for the formation of H2 in the solar neighborhood by comparing H i emission and absorption spectra toward 58 lines of sight at b < −5∘ to CO(1–0) and dust data. Our analysis of CO-associated cold and warm neutral medium (CNM and WNM) shows that the formation of CO-traced molecular gas is favored in regions with high column densities where the CNM becomes colder and more abundant. In addition, our comparison to the one-dimensional steady-state H i-to-H2 transition model of Bialy et al. (2016) suggests that only a small fraction of the clumpy CNM participates in the formation of CO-traced molecular gas. Another possible interpretation would be that missing physical and chemical processes in the model could play an important role in H2 formation.

Atomically sharpened tips have attracted much interest in the imaging and manufacturing fields due to their high spatial resolutions. Typically, tungsten (W) is mainly used as the material of such a tip, but when the W tip is used in an oxygen environment, a limit is revealed due to corrosiveness stemming from a reaction with the oxygen gas. To solve this problem, methods of depositing a metal on W that does not react with oxygen have been studied. In this study, we introduce a method of depositing iridium (Ir) directly onto an insulating layer without an additional pretreatment to remove the insulating layer remaining on the W surface, forming an Ir-nanopyramid structure at the apex of the W tip by field evaporation and faceting. Field ion microscopy and atom probe tomography were used to analyze the crystal structure and composition at the apex during the faceting process, and the overall tip shape change after faceting was compared and analyzed with transmission electron microscopy. The proposed method does not have a tip heating step when creating an atomically sharp tip such that it can be made easily with a simpler equipment configuration than in the existing method.

We aim to determine the association between Fe status and the metabolic syndrome (MetS) during menopause. Records of 1069 premenopausal and 703 postmenopausal Korean women were retrieved from the database of the fifth Korean National Health and Nutrition Examination Survey (KNHANES V 2012) and analysed. The association between the MetS and Fe status was performed using multivariable-adjusted analyses, subsequently develop a prediction model for the MetS by margin effects. We found that the risk of Fe depletion among postmenopausal women was lower than premenopausal women (PR = 0·813, 95 % CI 0·668, 0·998, P = 0·038). The risk of the MetS was 2·562-fold lower among premenopausal women with than without Fe depletion (PR = 0·390, 95 % CI 0·266, 0·571, P < 0·001). In contrast, the risk of the MetS tended to be higher among postmenopausal women with than without Fe depletion (PR = 1·849, 95 % CI 1·406, 2·432, P < 0·001). When the serum ferritin levels increased, the risk of the MetS increased in both premenopausal women and postmenopausal women. The margin effects showed that an increase in serum Hb and ferritin was associated with an increase in the risk of the MetS according to menopausal status and age group. Therefore, ferritin is the most validated and widely used Fe marker, could be a potential clinical value in predicting and monitoring the MetS during menopause. Further prospective or longitudinal studies, especially, clinically related studies on menopause and Fe status, are needed to clarify the causality between serum ferritin levels and the MetS that could offer novel treatments for the MetS.

This article reviews the advancements and prospects of liquid cell transmission electron microscopy (TEM) imaging and analysis methods in understanding the nucleation, growth, etching, and assembly dynamics of nanocrystals. The bonding of atoms into nanoscale crystallites produces materials with nonadditive properties unique to their size and geometry. The recent application of in situ liquid cell TEM to nanocrystal development has initiated a paradigm shift, (1) from trial-and-error synthesis to a mechanistic understanding of the “synthetic reactions” responsible for the emergence of crystallites from a disordered soup of reactive species (e.g., ions, atoms, molecules) and shape-defined growth or etching; and (2) from post-processing characterization of the nanocrystals’ superlattice assemblies to in situ imaging and mapping of the fundamental interactions and energy landscape governing their collective phase behaviors. Imaging nanocrystal formation and assembly processes on the single-particle level in solution immediately impacts many existing fields, including materials science, nanochemistry, colloidal science, biology, environmental science, electrochemistry, mineralization, soft condensed-matter physics, and device fabrication.

The experiments reported in this research paper aimed to determine the effect of supplementing different forms of L-methionine (L-Met) and acetate on protein synthesis in immortalized bovine mammary epithelial cell line (MAC-T cells). Treatments were Control, L-Met, conjugated L-Met and acetate (CMA), and non-conjugated L-Met and Acetate (NMA). Protein synthesis mechanism was determined by omics method. NMA group had the highest protein content in the media and CSN2 mRNA expression levels (P < 0.05). The number of upregulated and downregulated proteins observed were 39 and 77 in L-Met group, 62 and 80 in CMA group and 50 and 81 in NMA group from 448 proteins, respectively (P < 0.05). L-Met, NMA and CMA treatments stimulated pathways related to protein and energy metabolism (P < 0.05). Metabolomic analysis also revealed that L-Met, CMA and NMA treatments resulted in increases of several metabolites (P < 0.05). In conclusion, NMA treatment increased protein concentration and expression level of CSN2 mRNA in MAC-T cells compared to control as well as L-Met and CMA treatments through increased expression of milk protein synthesis-related genes and production of the proteins and metabolites involved in energy and protein synthesis pathways.