Hyuk Choi

Fe films grown in ultrahigh vacuum onto a curved Pd(001) substrate with a continuous gradient in atomic step density were studied in situ via the surface magneto-optic Kerr effect (SMOKE). The steps induce an in-plane, uniaxial magnetic anisotropy with the easy axis perpendicular to the step edges, and whose strength scales linearly with step density. The Curie temperature of 1--2 monolayers of Fe is enhanced by the steps relative to that on a flat substrate. The enhancement is attributed to a s

Intervertebral disc degeneration (IVD) is one of the important causes of low back pain and is associated with inflammation induced by interaction between macrophages and the human annulus fibrosus (AF) cells. Low-level light therapy (LLLT) has been widely known to regulate inflammatory reaction. However, the effect of LLLT on macrophage-mediated inflammation in the AF cells has not been studied till date. The aim of this study is to mimic the inflammatory microenvironment and to investigate the

Ultrathin Fe films were grown epitaxially onto a stepped W(001) substrate, polished with a curvature to provide a continuously variable step density, with the steps parallel to the [100] crystalline axis. The steps induce an in-plane uniaxial magnetic anisotropy with easy axis perpendicular to the step edges. We found that this step-induced magnetic anisotropy does not enhance the Curie temperature of the Fe film. The strength of the anisotropy varies quadratically with step density, but does no

Adipokine human Resistin (hResistin), is known to be associated with insulin resistance and secrete low-grade pro-inflammatory cytokines in obesity. Although studies on low-grade inflammation of adipokine hResistin are known, studies on the effects and mechanisms of intervertebral disc degeneration (IVDD) are still lacking. Thus, we investigated the adipokine hResistin with or without pro-inflammatory cytokine IL-1β in intervertebral disc (IVD) cells such as human annulus fibrosus (hAF) and nucl

Circulating tumor cells (CTCs) have attracted increasing attention as important biomarkers for clinical and biological applications. Several microfluidic approaches have been demonstrated to separate CTCs using immunoaffinity or size difference from other blood cells. This study demonstrates a sheathless, high-throughput separation of CTCs from white blood cells (WBCs) using a viscoelastic fluid. To determine the fluid viscoelasticity and the flow rate for CTC separation, and to validate the dev

To evaluate dominant cell-to-cell paracrine interactions, including those of human annulus fibrosus (AF), nucleus pulposus (NP), and endothelial cells (ECs), in the production of inflammatory mediators and catabolic enzymes, ECs was cultured in soluble factors derived from AF or NP cells (AFCM or NPCM, respectively) and vice versa. We analysed IL-6 and -8, vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-1 and -3, nerve growth factor (NGF)-β, and brain-derived neurotroph

Although allergic rhinitis is not life threatening, it significantly influences the quality of a patient's life. This study is intended to evaluate the safety and efficacy of phototherapy with low-level energy of a 650 nm laser irradiation system in perennial allergic rhinitis patients. This clinical trial was an open-label, single-center study with 42 perennial allergic rhinitis subjects. Following laser irradiation in the nasal cavity with a laser irradiation system, the efficacy at weeks 1 th

Abstract Intervertebral disc (IVD) degeneration is associated with imbalances between catabolic and anabolic responses, regulated by extracellular matrix (ECM)-modifying enzymes such as matrix metalloproteinases (MMPs) and their endogenous tissue inhibitors of metalloproteinases (TIMPs). Potential contributing factors, such as interleukin (IL)-1β and tumor necrosis factor (TNF)-α, derived from infiltrated, activated macrophages within IVD tissues, can trigger abnormal production of ECM-modifying

Spin reorientation transition (SRT) of Fe film in the magnetically coupled Fe/Cu/Ni/Cu(001) system was investigated by surface magneto-optic Kerr effect and photoemission electron microscopy. We found that the Fe in-plane magnetic remanence within the SRT region oscillates with the Cu layer thickness with a periodicity exactly half of that of the magnetic interlayer coupling. Element specific domain imaging shows that the Fe stripe domains within the SRT region are washed away by the magnetic in

Electrical stimulation of cells and tissues for therapeutic benefit is a well-established method. Although animal studies can emulate the complexity of an organism's physiology, lab-on-a-chip platforms provide a suitable primary model for follow-up animal studies. Thus, inexpensive and easy-to-use platforms for in vitro human cell studies are required. In the present study, we designed a micro-electrical impulse (micro-EI)-on-a-chip (micro-EI-chip), which can precisely control electron density a

In both Fe/W(001) and Fe/Pd(001) systems, the atomic steps induce an in-plane uniaxial magnetic anisotropy with the easy magnetization axis perpendicular to the step edges. The strength of the step-induced anisotropy was found to have a power law dependence on the step density: a quadratic dependence in the Fe/W system but a linear dependence in the Fe/Pd system. In addition, the Curie temperature is found to be higher on the stepped surface in the Fe/Pd system as compared to the flat surface. T