Publications by authors named "Dae Yun Kim"

Chiral magnets have garnered significant interest due to the emergence of unique phenomena prohibited in inversion-symmetric magnets. While the equilibrium characteristics of chiral magnets have been extensively explored through the Dzyaloshinskii-Moriya interaction (DMI), nonequilibrium properties like magnetic damping have received comparatively less attention. We present the inaugural direct observation of chiral damping through Brillouin light scattering (BLS) spectroscopy.

View Article and Find Full Text PDF

Increasing temperature can enhance the geographical spread and behavior of disease vector mosquitoes, exposing vulnerable populations to -borne viruses and infections. To address this risk, cost-effective and sustained intervention vector control tools are required, such as volatile pyrethroid spatial repellents. This study used a high-throughput screening system toxicity bioassay to determine the discriminating concentrations of transfluthrin-treated filter papers with variable air-drying times exposed to pyrethroid-susceptible mosquitoes.

View Article and Find Full Text PDF

Spin-transfer torque (STT) and spin-orbit torque (SOT) form the core of spintronics, allowing for the control of magnetization through electric currents. While the sign of SOT can be manipulated through material and structural engineering, it is conventionally understood that STT lacks a degree of freedom in its sign. However, this study presents the first demonstration of manipulating the STT sign by engineering heavy metals adjacent to magnetic materials in magnetic heterostructures.

View Article and Find Full Text PDF

is a major vector of dengue fever in tropical regions. Spatial repellents (SRs) have shown promise in delaying pesticide resistance. Methods for discriminating concentrations (DCs) are well established using various bioassay tools, while data for high-throughput screening system (HITSS) toxicity bioassay (TOX) are absent.

View Article and Find Full Text PDF

Herein, we report an exotic domain-wall dynamics showing double Walker breakdowns in magnetic multilayer films composed of two magnetic layers. Such multiple Walker breakdowns are attributed to the internal magnetic dipole field, which is antisymmetric on the domain walls of the lower and upper magnetic layers. A micromagnetic simulation shows four phases of the domain-wall dynamics, which result in a phase diagram with the phase boundaries of the double Walker breakdown fields.

View Article and Find Full Text PDF

Background: Entomological surveillance is an important means of assessing the efficacy of insect vector management programs and estimating disease transmission thresholds. Among baited traps, Biogents' BG-Sentinel (BGS) trap baited with BG-Lure is considered to have the most similar outcome to, and be a possible replacement for, human-landing catches for the epidemiologically relevant monitoring of adult Aedes aegypti and Culex quinquefasciatus. In contrast to the BGS trap, the Black Hole ultraviolet (UV) light trap, which is widely used to catch nocturnal flying insects, is not baited with synthetic human odor-mimicking lures.

View Article and Find Full Text PDF

Several types of olfactometers have been used to evaluate mosquito responses to agents that mimic natural volatiles that repel or attract. The Y-tube olfactometer has been widely used to study repellents and attractants, while the high-throughput screening system assay has only been used to study repellents. Whether the high-throughput screening system assay is suitable for evaluating attractants is unknown.

View Article and Find Full Text PDF

Natural volatile host cues play a critical role for mosquito orientation and locating a blood source for egg production. Similar olfactory activation responses have allowed the use and development of artificial chemical attractants to lure mosquitoes to trapping devices. Using a pre-formulated commercial product mixture of different attractant chemicals, a high-throughput screening system (HITSS) is used to screen varying doses of chemical required to activate behavioral responses.

View Article and Find Full Text PDF

This study examined the presence of insecticide resistance in different developmental stages (adults, first instars, and eggs) of the tropical bed bug, Cimex hemipterus (F.) using several insecticide formulations. Adults and first instars of five strains (Queensland, Kuala Lumpur, Bukit Mertajam, Saujana, and Krystal Point) were evaluated using the surface contact method and compared with a susceptible strain (Monheim) of the common bed bug Cimex lectularius L.

View Article and Find Full Text PDF

Background: Recently, several studies have assessed the association between diabetes and hearing impairment. However, the effect of diabetes on hearing impairment is not well known in diabetic patients exposed to noise, a typical cause of hearing impairment. The aim of this study is to longitudinally analyze the effect of diabetes on hearing impairment in workers exposed to similar noise levels from 2013 to 2017 who had experienced little change in their working conditions.

View Article and Find Full Text PDF

Symmetry breaking is a fundamental concept that prevails in many branches of physics. In magnetic materials, broken inversion symmetry induces the Dzyaloshinskii-Moriya interaction (DMI), which results in fascinating physical behaviours with the potential for application in future spintronic devices. Here, we report the observation of a bulk DMI in GdFeCo amorphous ferrimagnets.

View Article and Find Full Text PDF

Background: The detection rate of hand-arm vibration syndrome (HAVS) is very low in South Korea compared with other countries. The absence of uniform consensus and guidelines for diagnosing HAVS has been presumed to be one of the reasons. The HAVS has various manifestations including cold intolerance and its severity can be measured using the cold intolerance symptom severity (CISS) questionnaire.

View Article and Find Full Text PDF

In the presence of a magnetic field, the flow of charged particles in a conductor is deflected from the direction of the applied force, which gives rise to the ordinary Hall effect. Analogously, moving skyrmions with non-zero topological charges and finite fictitious magnetic fields exhibit the skyrmion Hall effect, which is detrimental for applications such as skyrmion racetrack memory. It was predicted that the skyrmion Hall effect vanishes for antiferromagnetic skyrmions because their fictitious magnetic field, proportional to net spin density, is zero.

View Article and Find Full Text PDF

Unidirectional motion of magnetic structures such as the magnetic domain and domain walls is a key concept underlying next-generation memory and logic devices. As a potential candidate of such unidirectional motion, it has been recently demonstrated that the magnetic bubblecade-the coherent unidirectional motion of magnetic bubbles-can be generated by applying an alternating magnetic field. Here we report the optimal configuration of applied magnetic field for the magnetic bubblecade.

View Article and Find Full Text PDF

The Dzyaloshinskii-Moriya interaction (DMI) in magnetic objects is of enormous interest, because it generates built-in chirality of magnetic domain walls (DWs) and topologically protected skyrmions, leading to efficient motion driven by spin-orbit torques. Because of its importance for both potential applications and fundamental research, many experimental efforts have been devoted to DMI investigation. However, current experimental probing techniques cover only limited ranges of the DMI strength and have specific sample requirements.

View Article and Find Full Text PDF

The climbing abilities of two bed bug species, Cimex lectularius L. and Cimex hemipterus (F.), were determined by evaluating their escape rates from smooth surface pitfall traps using four commercial bed bug monitors (Verifi Bed Bug Detector, ClimbUp Insect Interceptor, BlackOut Bed Bug Detector, and SenSci Volcano Bed Bug Detector).

View Article and Find Full Text PDF

We demonstrate a cylindrical water triboelectric nanogenerator (CW-TENG) that generates sustainable electrical output. The inner surface of the cylinder was patterned into superhydrophobic and hydrophilic parts to control water flow inside the packaged design of CW-TENG. Here, various thicknesses and roughnesses of the superhydrophobic surface, generated using aluminum oxide nanostructures for enhanced electrostatic induction, were measured to obtain the maximum output and superhydrophobicity.

View Article and Find Full Text PDF

Background: Few studies have investigated the impact of diabetes mellitus (DM), a globally increasing metabolic disease, on treatment outcomes and long-term survival in patients with multidrug-resistant forms of tuberculosis (MDR-TB).

Objectives: We analyzed outcomes in a large cohort to assess the impact of DM on treatment outcomes of patients with MDR-TB.

Methods: MDR-TB patients newly diagnosed or retreated between 2000 and 2002 and followed for 8-11 years were retrospectively analyzed with respect to the effect of DM as a comorbidity on their treatment outcome and long-term survival.

View Article and Find Full Text PDF

This study was conducted to evaluate treatment outcome, mortality, and predictors of both in patients with multidrug-resistant tuberculosis (MDR-TB) at 3 TB referral hospitals in the public sector of Korea. We included MDR-TB patients treated at 3 TB referral hospitals in 2004 and reviewed retrospectively their medical records and mortality data. Of 202 MDR-TB patients, 75 (37.

View Article and Find Full Text PDF

Purpose: A decreased percent of differential function is a common indication for infant pyeloplasty but there is no recognized fetal ultrasound parameter to predict this deficit. We determined whether there is a correlation between fetal pyelectasis and the newborn percent differential function that may enhance prenatal counseling and guide postnatal evaluation.

Materials And Methods: Our database was queried for fetal and newborn measures with fetal pyelectasis on ultrasound and the percent of differential function on renal scintigraphy.

View Article and Find Full Text PDF

Objective: To compare the outcomes between patients with stage T1a/b with those of patients with T1c cancer of the prostate treated with radical retropubic prostatectomy (RRP), as the appropriate management of clinical stage T1a/b prostate cancer is subject to debate; although many patients are managed expectantly, some have adverse pathological features suggesting that more active treatment might be beneficial.

Patients And Methods: From 1983 to 2003, 3478 men had RRP by one surgeon. From this group, we retrospectively identified 29 men with clinical stage T1a and 83 with clinical stage T1b disease.

View Article and Find Full Text PDF

We report the activity, stability, and reusability of enzyme-carbon nanotube conjugates in aqueous solutions. A variety of enzymes were covalently attached to oxidized multi-walled carbon nanotubes (MWNTs). These conjugates were soluble in aqueous buffer, retained a high fraction of their native activity, and were stable at higher temperatures relative to their solution phase counterparts.

View Article and Find Full Text PDF

Silicon nanocolumns have been used as novel supports for the high-density immobilization of enzymes. Silicon nanocolumns with diameters of ca. 50-100 nm and a height of 1 micron were constructed using glancing angle deposition.

View Article and Find Full Text PDF

Background/aims: Lamivudine, an oral nucleoside analogue, effectively suppresses hepatitis B virus (HBV) replications and improves liver enzymes as well as liver histology. The aim of this study was to evaluate the effectiveness of lamivudine and the patient-dependent or laboratory variables that predict HBeAg seroconversion.

Methods: We retrospectively analyzed 519 consecutive patients with HBeAg-positive chronic hepatitis B who were treated with lamivudine.

View Article and Find Full Text PDF