The aim of this study was to evaluate the impact of coronavirus disease 2019 (COVID-19) on treatment outcomes in critically ill patients with carbapenem-resistant Acinetobacter baumannii (CRAB) bloodstream infection (BSI). This single-centre, retrospective cohort study was conducted in a 1,048-bed university-affiliated tertiary hospital in the Republic of Korea from January 2021 to March 2022. The study participants included consecutive hospitalised adult patients (aged ≥18 years) in the intensive care unit with CRAB monomicrobial BSI. During the study period, a total of 70 patients were included in our study, and 24 (34.3%) were diagnosed with COVID-19. The 28-day mortality rate was 64.3%. In the multivariate Cox proportional hazard regression analysis, diagnosis of COVID-19 (hazard ratio (HR), 2.91; 95% confidence interval (CI): 1.45–5.87), neutropenia (HR, 2.76; 95% CI: 1.04–7.29), Pitt bacteraemia score (per point; HR, 1.30; 95% CI: 1.19–1.41), and appropriate definite antibiotic therapy (HR, 0.31; 95% CI: 0.15–0.62) were independent predictors of 28-day mortality in patients with CRAB BSI. In conclusion, our findings suggested that COVID-19 has a negative prognostic impact on patients with CRAB BSI. Further study is needed to investigate the specific mechanisms of how COVID-19 worsens the prognosis of CRAB infection.

Globally, an aging population is increasing, and aging is a natural physiological process and a major risk factor for all age-related diseases. It seriously threatens personal health and imposes a great economic burden. Therefore, there is a growing scientific interest in strategies for well-aging with prevention and treatment of age-related diseases. The seed, root, stem or leaves of Cassia tora Linn. are useful for anti-bacteria, anti-hyperlipidemia and anti-obesity due to its pharmacological activities such as anti-inflammation and anti-oxidant both in vitro and in vivo. Nevertheless, no clinical trials have been attempted so far, therefore here we would like to understand the current preclinical activities for aging-related disease models including cataract, metabolic dysfunction and neurodegeneration, then discuss their preparation for clinical trials and perspectives.

Background: Although small- and medium-sized hospitals comprise most healthcare providers in South Korea, data on antibiotic usage is limited in these facilities. We evaluated the pattern of antibiotic usage and its appropriateness in hospitals with <400 beds in South Korea. Methods: A multicenter retrospective study was conducted in 10 hospitals (6 long-term care hospitals, 3 acute-care hospitals, and 1 orthopedic hospital), with <400 beds in South Korea. We analyzed patterns of antibiotic prescription and their appropriateness in the participating hospitals. Data on the monthly antibiotic prescriptions and patient days for hospitalized patients were collected using electronic databases from each hospital. To avoid the effect of the COVID-19 pandemic, data were collected from January to December 2019. For the evaluation of the appropriateness of the prescription, 25 patients under antibiotic therapy were randomly selected at each hospital over 2 separate periods. Due to the heterogeneity of their characteristics, the orthopedics hospital was excluded from the analysis. The collected data were reviewed, and the appropriateness of antibiotic prescriptions was evaluated by 5 specialists in infectious diseases (adult and pediatric). Data from 2 hospitals were assigned to each specialist. The appropriateness of antibiotic prescriptions was evaluated from 3 aspects: route of administration, dose, and class. If the 3 aspects were ‘optimal,’ the prescription was considered ‘optimal.’ If only the route was ‘optimal,’ and the dose and/or class was ‘suboptimal,’ but not ‘inappropriate,’ it was considered ‘suboptimal.’ If even 1 aspect was ‘inappropriate,’ it was classified as ‘inappropriate.’ Results: The most commonly prescribed antibiotics in long-term care hospitals was fluoroquinolone, followed by β-lactam/β-lactamase inhibitor (antipseudomonal). In acute-care hospitals, these were third-generation cephalosporin, followed by first-generation cephalosporin and second-generation cephalosporin. The major antibiotics that were prescribed in the orthopedics hospital was first-generation cephalosporin. Only 2.3% of the antibiotics were administered inappropriately. In comparison, 15.3% of patients were prescribed an inappropriate dose. The proportion of inappropriate antibiotic prescriptions was 30.6% of the total antibiotic prescriptions. Conclusions: The antibiotic usage patterns vary between small- and medium-sized hospitals in South Korea. The proportion of inappropriate prescriptions exceeded 30% of the total antibiotic prescriptions.

Funding: None

Disclosures: None

The dissipation of ion-acoustic surface waves propagating in a semi-bounded and collisional plasma which has a boundary with vacuum is theoretically investigated and this result is used for the analysis of edge-relevant plasma simulated by Divertor Plasma Simulator-2 (DiPS-2). The collisional damping of the surface wave is investigated for weakly ionized plasmas by comparing the collisionless Landau damping with the collisional damping as follows: (1) the ratio of ion temperature $({T_i})$ to electron temperature $({T_e})$ should be very small for the weak collisionality $({T_i}/{T_e} \ll 1)$; (2) the effect of collisionless Landau damping is dominant for the small parallel wavenumber, and the decay constant is given as $\gamma \approx{-} \sqrt {\mathrm{\pi }/2} {k_\parallel }{\lambda _{De}}\omega _{pi}^2/{\omega _{pe}}$; and (3) the collisional damping dominates for the large parallel wavenumber, and the decay constant is given as $\gamma \approx{-} {\nu _{in}}/16$, where ${\nu _{in}}$ is the ion–neutral collisional frequency. An experimental simulation of the above theoretical prediction has been done in the argon plasma of DiPS-2, which has the following parameters: plasma density ${n_e} = (\textrm{2--9)} \times \textrm{1}{\textrm{0}^{11}}\;\textrm{c}{\textrm{m}^{ - 3}}$, ${T_e} = 3.7- 3.8\;\textrm{eV}$, ${T_i} = 0.2- 0.3\;\textrm{eV}$ and collision frequency ${\nu _{in}} = 23- 127\;\textrm{kHz}$. Although the wavelength should be specified with the given parameters of DiPS-2, the collisional damping is found to be $\gamma = ( - 0.9\;\textrm{to}\; - 5) \times {10^4}\;\textrm{rad}\;{\textrm{s}^{ - 1}}$ for ${k_\parallel }{\lambda _{De}} = 10$, while the Landau damping is found to be $\gamma = ( - 4\;\textrm{to}\; - 9) \times {10^4}\;\textrm{rad}\;{\textrm{s}^{ - 1}}$ for ${k_\parallel }{\lambda _{De}} = 0.1$.

Litter-dwelling arthropods play an important role in maintaining forest ecosystem function. This study was designed to understand seasonal variations and diversity of litter-dwelling adult beetles, one of the most diverse groups of arthropods. Sampling was conducted in mixed-wood forests of South Korea between March and December 2019, covering all seasons, including winter. We used a sifting method and a Berlese funnel to collect arthropods living in leaf litter and soil. We collected a total of 5820 invertebrates representing six orders, of which 1422 were beetles representing 24 families and minimum 141 species. Beetle species richness was highest in spring and lowest in summer based on rarefaction and extrapolation. However, beetle abundance was lowest in spring, but abundance was similar among the other seasons. Beetle assemblage composition was correlated significantly with soil surface and atmospheric temperature. The assemblage composition differed among seasons, except between spring and winter, which overlapped slightly. The combined sifting–Berlese funnel method showed great advantages for investigating the diversity of overwintering arthropods. Continued study of the relationship between arthropods and the leaf-litter environment is essential to understand this microecosystem and will increase the chance of discovering new beetle species.

The explosive outbreak of COVID-19 led to a shortage of medical resources, including isolation rooms in hospitals, healthcare workers (HCWs) and personal protective equipment. Here, we constructed a new model, non-contact community treatment centres to monitor and quarantine asymptomatic and mildly symptomatic COVID-19 patients who recorded their own vital signs using a smartphone application. This new model in Korea is useful to overcome shortages of medical resources and to minimise the risk of infection transmission to HCWs.

Radiocarbon (14C) dating has been widely used to determine the age of deposits, but there have been frequent reports of inconsistencies in age among different dating materials. In this study, we performed radiocarbon dating on a total of 33 samples from 8-m-long sediment cores recovered from the wetland of the Muljangori volcanic cone on Jeju Island, South Korea. Ten pairs of humic acid (HA) and plant fragments (PF) samples, and three pairs of HA and humin samples, from the same depths were compared in terms of age. The PF were consistently younger than the HA. Interestingly, the age difference between HA and PF samples showed a long-term change during the past 8000 years. To test whether there was an association between this long-term age difference and climate change, we compared with the carbon/nitrogen (C/N) ratios and total organic carbon isotope (δ13CTOC) values of the sediments, as indicators of the relative abundance of terrestrial and aquatic plants; these parameters showed similar long-term trends. This suggests that the increasing (decreasing) trend in age difference was influenced by long-term dry (wet) climate change.

Periodontitis, or conventionally “Gum Disease,” is the infection and inflammation of gingival tissue, and is currently the leading cause of tooth loss in the United States. One of the most effective treatments of periodontitis is guided bone regeneration (GBR); however, current GBR barrier membranes lack high biocompatibility and cell impermeability. The authors of this study evaluated the in vitro viability of previously synthesized Gelatin-Pluronic® F127 hybrid hydrogels as potential GBR barrier membranes through a novel three-partition test involving migration of fluorescent-dyed human dermal fibroblasts. Results showed that cells were unable to migrate across the Gelatin-Pluronic® F127 hybrid hydrogel barrier, whereas control setups with gelatin hydrogel barriers showed cell permeability. In addition, cytotoxicity tests were conducted with fibroblasts plated in both cell mediums that had been incubated while in contact hybrid gels and cell mediums suspended on the surface of hybrid gels during swelling procedures. Fluorescence cell plate readings showed similar cell viability across data from both tests, indicating that Gelatin-Pluronic® F127 hybrid hydrogels are not toxic to cells, and thus biocompatible.

The study of extremely metal-poor (EMP; [Fe/H] <−3.0) and ultra metal-poor (UMP; [Fe/H] <−4.0) stars is crucial for better understanding first-star nucleosynthesis and constraining the initial mass function in the early Universe. However, UMP stars discovered in the past 25 years only number ~25. A few recent theoretical studies have pointed out that there is likely to exist large numbers of EMP and UMP stars in the periphery of the Galactic halo, at distances exceeding 30-50 kpc. We present identifications of several new EMP/UMP stars and introduce a survey to expedite discovering hundreds to thousands of EMP/UMP stars in the outermost halo (as well as in the local volume) over the next few years, which could revolutionize chemical-evolution studies of the Galaxy.

There is growing evidence that, among the various subclasses of carbon-enhanced metal-poor (CEMP) stars, the outer halo of the Milky Way exhibits a higher frequency of CEMP-no stars (those having no over-abundances of heavy neutron-capture elements) compared with the CEMP-s stars (those with over-enhancements of the s-process elements), while the inner halo shows a higher frequency of CEMP-s stars. We map out fractions of CEMP-no and CEMP-s stars in the inner- and outer-halo populations, separated by their spatial distribution of carbonicity ([C/Fe]), a so-called “carbonicity map”, based on a sample of over 100,000 main-sequence turnoff stars with available spectroscopy from the Sloan Digital Sky Survey. The CEMP-no and CEMP-s objects are classified by different levels of absolute carbon abundances for our sample, A(C). We also present kinematic and orbital characteristics of these subclasses for each population. The contrast appearing in these characteristics provides critical constraints on the assembly history of the two primary stellar components of the Galactic halo.

We present the derived kinematic characteristics of low-α thin-disk and high-α thick-disk stars in the Milky Way, investigated with a sample of about 32,000 G- and K-type dwarfs from the Sloan Extension for Galactic Understanding and Exploration (SEGUE). Based on the level of α-element enhancement as a function of [Fe/H], we separate our sample into thin- and thick-disk stars and then derive mean velocities, velocity dispersions, and velocity gradients for the U, V, and W velocity components, respectively, as well as the orbital eccentricity distribution. There are notable gradients in the V velocity over [Fe/H] in both populations: −23 km s−1 dex−1 for the thin disk and +44 km s−1 dex−1 for the thick disk. The velocity dispersion of the thick disk decreases with increasing [Fe/H], while the velocity dispersion gradient over [Fe/H] for the thin disk is almost flat for all velocity components, except for the W velocity dispersion of the metal-poor thin-disk stars. The eccentricity distribution exhibits a peak at a higher value, and is more symmetric as [α/Fe] increases, implying that complex formation mechanisms may be involved. Our results can be used to constrain several proposed disk-formation scenarios of the Milky Way and other large spirals.

To trace the surficial responses of lowlands to past climate change, we investigated δ13C in total organic carbon (TOC), C/N ratios, magnetic susceptibility (MS), and silicon (Si) intensity (directly proportional to concentration) in wetland sediments collected from the Gimpo area of central Korea, covering 6600–4600 cal yr BP. Two organic layers with high TOC%, negatively depleted δ13CTOC values (− 27 to − 29‰), low MS values, and low Si intensities were found at 6200–5900 and 5200–4800 cal yr BP, respectively. These middle Holocene wet periods corresponded to relatively intensified summer monsoon and solar activity periods. The intervening dry period (5900–5200 cal yr BP) with high MS, high Si, and low TOC% corresponded to an intensified dust-activity interval and stronger winter monsoon. This multi-centennial climatic fluctuation of wet periods (6200–5900 cal yr BP and 5200–4800 cal yr BP) and an intervening dry period (5900–5200 cal yr BP) in central Korea was more synchronous with climate change in the arid inner part of China than with that in South China, suggesting possible strong high-latitude-driven climatic influences (e.g., North Atlantic cooling events) during the middle Holocene.

Late Pleistocene carbon isotope (δ13C) records from a paleolithic sedimentary sequence collected from Baeki, Hongcheon, central Korea, show long-term changes with superimposed short-term isotopic excursions. The δ13C value of the sedimentary organic matter, a proxy for past vegetation change, varied from − 26‰ to − 23‰ for the period between 30 and 90 ka, with a long-term variation similar to insolation changes. High-amplitude (− 1‰ to approximately − 1.5‰) fluctuations superimposed on the long-term changes in the δ13C values decreased during stronger summer monsoon intervals but increased during the weakened summer monsoon. This millennial-scale pattern is generally similar to Greenland Dansgaard–Oeschger (D–O) cycles. The possible connection between the Hongcheon area, Korea and high latitudes may be explained by atmospheric circulation changing in response to the D–O oscillations in the Northern Hemisphere.