Climate change poses a major threat to marine ecosystems, with its effects felt worldwide. A major effect of climate change on marine ecosystems is the rise in water temperature, leading to a northward expansion of habitats for marine organisms. Herdmania momus, a species of ascidians (sea squirts), originally found in tropical and subtropical regions, was introduced to the Korean Peninsula. In this study, we examined the habitat of H. momus along the southeastern coast of the Korean Peninsula between 2016 and 2022. We found that H. momus settlements were observed across the entire survey area, with confirmed habitation in Busan in 2016, Ulsan in 2021, and Gyeongju (the northernmost location) in 2022. The observed habitation trend indicates a rapid geographical expansion, occurring approximately 79 years earlier than previously predicted. These observations demonstrate that marine organisms are undergoing a more rapid geographical expansion than previously projected. These unexpected findings should inform government policies related to proactive measures and strategies for managing the impact of climate change on marine ecosystems.

The development of nanoparticles incorporating Gd3+ has attracted interest in the field of contrasting nanomedicine for magnetic resonance (MR) and computed tomography (CT). In order to achieve an effective contrasting performance, the amount and stability of Gd incorporated as well as particle-size control of the nanoparticles should be considered simultaneously. In the current study, Gd-diethylenetriaminepentaacetate(Gd-DTPA) was incorporated into layered double hydroxide (LDH) to meet the physicochemical properties required for MR-CT dual contrasting nanomedicine. Strategically, the particle size and nanometer incorporation of Gd-DTPA into LDH (GL-R hybrid) were controlled homogeneously using the reverse micelle method. X-ray diffraction showed that the hybrid obtained possessed a hydrotalcite phase. Dynamic light scattering and electron microscopic analyses showed that the hybrid had a controlled size of <200 nm with significant homogeneity. Fast Fourier-transform of transmission electron microscopy confirmed that the platelets of the GL-R hybrids were oriented randomly to form inter-particle space, enabling the Gd-DTPA moiety to be encapsulated stably. The encapsulation efficiency of Gd-DTPA was 20.8%, which was sufficiently high compared with other Gd-DTPA-incorporatedLDH. According to X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy, Gd-DTPA incorporated in the hybrid preserved its structure intact. Its potential as a dual modal contrast agent was demonstrated by measuring the concentration-dependent Hounsfield unit and magnetic resonance relaxivity, which were determined to be 230 at 2 mg/mL and 5.8 in the range ~0.2–1 mM-Gd, respectively.

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. 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 1633 patients from a large-scale multicentre 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 high-sensitivity troponin T ≥ 14 ng/l. OR and 95 % (CI for cardiac injury were calculated using logistic regression analyses. Of 1633 patients, the mean spot urinary potassium to creatinine ratio was 49·5 (sd 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 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.

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.

Adequate facepiece fit of N95 filtering facepiece respirators (FFRs) is crucial for optimal protection against airborne pathogens. The quantitative fit test (QNFT) pass rates of the 4 N95 FFR models commonly used in Korea were below 50%. Male sex was identified as a single independent predictive factor for QNFT pass.

Infect Control Hosp Epidemiol 2018;39:104–107

Echinochloa species are among the most troublesome weeds in rice cultivation, and grow in a broad habitat range in Korea. Although various ecotypes of Echinochloa have been collected as germplasm for future studies, it has been difficult to classify them due to their high level of morphological similarity. This study was thus conducted to develop and investigate the phylogenetic relationships between 77 Echinochloa accessions with the use of 23 simple sequence repeat (SSR) markers and 24 morphological traits. Of 77 Echinochloa accessions, including 57 accessions from Korea and 5 reference species, late watergrass was clearly clustered as a distinctive group from barnyardgrass and other Echinochloa species. In this analysis, we also identified core genetic and morphological markers that can be used for the future identification and classification of Echinochloa species. Five out of 23 SSR makers produced distinctive bands that discriminate late watergrass from barnyardgrass and other Echinochloa species. Four morphological traits of the reproductive organs were the most influential contributors for classifying Echinochloa species. Although there was no clear consensus generated in this study between SSR markers and morphological trait analyses, our results support the potential use of the selected SSR markers and morphological traits in future studies of Echinochloa.

Feasibility of multiwavelength Raman spectroscopy was studied as a potentialin-line monitoring technique for grain size distribution in channel poly-Si usedin three dimensional stacked NAND (3D NAND) Flash memory devices. Variouschannel poly-Si materials in 3D-NAND Flash memory devices, converted fromchemical vapor deposition (CVD) grown a-Si, were characterized usingnon-contact, multiwavelength Raman spectroscopy and high resolutioncross-sectional transmission electron microscopy (HRXTEM). The Ramancharacterization results were compared with HRXTEM images. The correlationbetween the grain size distribution characterized by multiwavelength Ramanspectroscopy and “on current” (ION) of 3D NANDFlash memory devices was investigated. Good correlation between these techniqueswas seen. Multiwavelength Raman spectroscopy is very promising as anon-destructive in-line monitoring technique for grain size distribution inchannel poly-Si used in 3D NAND Flash memory devices.

Genetic variation in wild soybean (Glycine soja Sieb. and Zucc.) is a valuable resource for crop improvement efforts. Soybean is believed to have originated from China, Korea, and Japan, but little is known about the diversity or evolution of Korean wild soybean. Therefore, in this study, we evaluated the genetic diversity and population structure of 733 G. soja accessions collected in Korea using 21 simple sequence repeat (SSR) markers. The SSR loci produced 539 alleles (25.7 per locus) with a mean genetic diversity of 0.882 in these accessions. Rare alleles, those with a frequency of less than 5%, represented 75% of the total number. This collection was divided into two populations based on the principal coordinate analysis. Accessions from population 1 were distributed throughout the country, whereas most of the accessions from population 2 were distributed on the western side of the Taebaek and Sobaek mountains. The Korean G. soja collection evaluated in this study should provide useful background information for allele mining approach and breeding programmes to introgress alleles into the cultivated soybean (G. max (L). Merr.) from wild soybean.

Liposomal drug delivery products have been already commercialized in tumor therapeutics, which can realize passive tumor targeting via enhanced permeability and retention (EPR) effect resulting from the leaky tumor vasculature. To control drug release out of the liposomes, thermo-sensitive liposomes (TSLs) have been developed so that an abrupt exposure of highly concentrated drugs to tumor tissues was enabled by locally treated thermal stimuli. As interests upon TSL have increased along with ongoing clinical trials, some types of TSLs with different physical properties in pharmacokinetics and the mechanism of drug release have been formulated. However, there are few protocols established with a desirable heat source to maximize the efficacy of different TSLs as treating tumors. In this study, we examined different protocols for the most effective application of different TSLs to tumor therapy. First, we examined if enhancing the accumulation of TSLs within tumor tissues prior to bursting drugs out of TSLs could lead to increasing anti-tumor efficacy. Second, we compared the efficiency of two different heat sources on the use of TSL, a warm water bath (42°C) and high intensity focused ultrasound (HIFU). Our study suggests that the specified protocol be setup for TSLs with different physical properties to optimally function in tumor therapies.

Sources of variation in nutrient intake have been examined for Western diets, but little is known about the sources of variation and their differences by age and sex among Koreans. We examined sources of variation in nutrient intake and calculated the number of days needed to estimate usual intake using 12 d of dietary records (DR). To this end, four 3 d DR including two weekdays and one weekend day were collected throughout four seasons of 1 year from 178 male and 236 female adults aged 20–65 years residing in Seoul, Korea. The sources of variation were estimated using the random-effects model, and the variation ratio (within-individual:between-individual) was calculated to determine a desirable number of days. Variations attributable to the day of the week, recording sequence and seasonality were generally small, although the degree of variation differed by sex and age (20–45 years and 46–65 years). The correlation coefficient between the true intake and the observed intake (r) increased with additional DR days, reaching 0·7 at 3–4 d and 0·8 at 6–7 d. However, the degree of increase became attenuated with additional days: r increased by 13·0–26·9 % from 2 to 4 d, by 6·5–16·4 % from 4 to 7 d and by 4·0–11·6 % from 7 to 12 d for energy and fifteen nutrients. In conclusion, the present study suggests that the day of the week, recording sequence and seasonality minimally contribute to the variation in nutrient intake. To measure Korean usual dietary intake using open-ended dietary instruments, 3–4 d may be needed to achieve modest precision (r>0·7) and 6–7 d for high precision (r>0·8).

The Ultra-Fast Flash Observatory (UFFO), which will be launched onboard theLomonosov spacecraft, contains two crucial instruments: UFFO BurstAlert & Trigger Telescope (UBAT) for detection and localization of Gamma-Ray Bursts(GRBs) and the fast-response Slewing Mirror Telescope (SMT) designed for the observationof the prompt optical/UV counterparts. Here we discuss the in-space calibrations of theUBAT detector and SMT telescope. After the launch, the observations of the standard X-raysources such as pulsar in Crab nebula will provide data for necessary calibrations ofUBAT. Several standard stars will be used for the photometric calibration of SMT. Thecelestial X-ray sources, e.g. X-ray binaries with bright optical sourcesin their close angular vicinity will serve for the cross-calibration of UBAT and SMT.