Metastable hard-axis polar state of a spinor Bose-Einstein condensate under a magnetic field gradient

We investigate the stability of a hard-axis polar state in a spin-1 antiferromagnetic Bose-Einstein condensate under a magnetic field gradient, where the easy-plane spin anisotropy is controlled by a negative quadratic Zeeman energy q<0. In a uniform magnetic field, the axial polar state is dynamically unstable and relaxes into the planar polar ground state. However, under a field gradient B′, the excited spin state becomes metastable down to a certain threshold qth, and as q decreases below qth its intrinsic dynamical instability is rapidly recalled. The incipient spin excitations in the relaxation dynamics appear with stripe structures, indicating the rotational symmetry breaking by the field gradient. We measure the dependences of qth on B′ and the sample size, and we find that qth is highly sensitive to the field gradient in the vicinity of B′=0, exhibiting power-law behavior of |qth|-B′α with α∼0.5. Our results demonstrate the significance of the field gradient effect in the quantum critical dynamics of spinor condensates. © 2019 American Physical Societ

Collisional Dynamics of Half-Quantum Vortices in a Spinor Bose-Einstein Condensate

We present an experimental study on the interaction and dynamics of half-quantum vortices (HQVs) in an antiferromagnetic spinor Bose-Einstein condensate. By exploiting the orbit motion of a vortex dipole in a trapped condensate, we perform a collision experiment of two HQV pairs, and observe that the scattering motions of the HQVs is consistent with the short-range vortex interaction that arises from nonsingular magnetized vortex cores. We also investigate the relaxation dynamics of turbulent condensates containing many HQVs, and demonstrate that spin wave excitations are generated by the collisional motions of the HQVs. The short-range vortex interaction and the HQV-magnon coupling represent two characteristics of the HQV dynamics in the spinor superfluid. © 2016 American Physical Society113131sciescopu

Cosmetic surgery on YouTube: a content analysis of East Asian blepharoplasty-related videos in South Korea

Background : : As social media gets commonly used worldwide, there is an enormous amount of information available on YouTube. While cosmetic surgery-related content in English on YouTube has been studied priorly, those in Korean have not been explored.Objective: The purpose of this study is to analyze the status quo of aesthetic-related content, specifically on East Asian blepharoplasty, on YouTube in South Korea.Methods : : The 535 returned videos for the search term ‘SSangkkeopul Susul’, the Korean word for East Asian blepharoplasty, were collected on July 9, 2020, and classified by types of content and uploader, view counts, and length of videos, then, analyze, using Excel (Microsoft).Results : : Fifty five percent of collected videos was to provide surgery-related information, and 20.0% was to show patient experience. Also, 76.8% of the videos were uploaded by medical doctors or clinics, while 13.6% was uploaded by personal accounts and 5.4% by content creators. The most common type of content was surgery-related information uploaded by medical doctors and clinics, followed by patient experience posted by personal channels. The average length of all videos was 4 minutes 46 seconds. However, among the ten most-viewed videos, only one was uploaded by medical doctor and the others were uploaded by non-medical personnel.Conclusion : : Medical doctors have a quantitatively huge influence on cosmetic surgery-related content on YouTube in Korea, which leads the information in those videos more reliable. However, due to the lack of clarity in relevant regulations and the absence of constant monitoring, potentially harmful or sensitive contents are still available on YouTube. Thus, preventative measures at the governmental level are needed

Impact of Alcohol-Induced Facial Flushing Phenotype on Alcohol Consumption Among Korean Adults: 2-Year Cross-Sectional Study

BackgroundThe alcohol-induced facial flushing phenotype (flushing) is common among East Asians. Despite a small intake of alcohol, they experience heightened levels of acetaldehyde, a group-1 carcinogen, which, in turn, causes unpleasant symptoms such as redness, acting as a robust protective mechanism against consuming alcohol. However, some individuals with this genetic trait exhibit weakened alcohol restraint, which increases the risk of developing alcohol-related cancers, such as esophageal and head or neck cancer, by several times. Although this flushing phenomenon is crucial for public health, there is a paucity of studies that have comprehensively investigated the effect of flushing or its genotype on alcohol consumption in a large group of East Asians while controlling for various sociodemographic and health-related variables at a country level. ObjectiveThis 2-year cross-sectional study aims to explore the effect of flushing on drinking behavior in Koreans and to examine whether the effect varies across sociodemographic and health-related factors. MethodsWe used data from the Korea National Health and Nutrition Examination Survey (KNHANES) for 2019 and 2020 conducted by the Korea Disease Control and Prevention Agency. Our sample comprised 10,660 Korean adults. The study investigated the association of 26 variables, including flushing, with drinking frequency and amount. The effect of flushing was examined with and without adjusting for the other 25 variables using multinomial logistic regression analysis. In addition, we tested the interaction effect with flushing and conducted a simple effect analysis. We used complex sample design elements, including strata, clusters, and weights, to obtain unbiased results for the Rao-Scott χ2 test, 2-tailed t test, and multinomial logistic regression analysis. ResultsThe suppressive effect of flushing was significant (P<.001) across all pronounced categories of alcohol consumption in 2019. The ranges of standardized regression slopes and odds ratios (ORs) were –6.70≥β≥–11.25 and 0.78≥OR≥0.50 for frequency and –5.37≥β≥–17.64 and 0.73≥OR≥0.36 for amount, respectively. The effect became somewhat stronger when adjusted for confounders. The effect also exhibited an overall stronger trend as the severity of alcohol consumption increased. The β values and ORs were consistently smaller in 2020 compared to the previous year. A simple effect analysis revealed a diminished alcohol-suppressive effect of flushing on alcohol consumption for specific groups (eg, those with low levels of education, limited family support, physical labor, or health-related issues). ConclusionsOur findings suggest that flushing suppresses drinking in Koreans overall but has little or no effect in certain susceptible populations. Therefore, health authorities should conduct targeted epidemiological studies to assess drinking patterns and disease profiles, particularly regarding alcohol-related cancers, and establish effective preventive measures tailored to this population

Adverse Reactions after Administration of Antivenom in Korea

Kovax® antivenom is the main treatment for toxins produced by the Gloydius species. However, research on adverse reactions after Kovax® antivenom administration is scarce. We aimed to identify the incidence and characteristics of adverse reactions after Kovax® antivenom administration. We conducted a retrospective review of the medical records of snakebite patients in Korea between January 2008 and September 2019. We identified the frequency, characteristics, and treatments of adverse reactions to Kovax® antivenom. There were 150 patients with snakebites, of whom 121 (80.7%) patients received Kovax® antivenom. Adverse reactions occurred in five patients (4.1%). Acute adverse reactions within 24 h of antivenom administration occurred in two patients (1.7%). The symptoms of patients with acute adverse reactions were nausea, diaphoresis, dizziness, and hypotension. Delayed adverse reactions that occurred 24 h after antivenom administration were reported in three patients (2.5%). One patient had a skin rash after 10 days, and two patients had fever 37 and 48 h after antivenom use. In conclusion, most patients were managed safely after Kovax® antivenom, and the incidence of adverse reactions was low. Severe adverse reactions occurred in a small percentage of patients, and there were no deaths.</jats:p