Publications by authors named "Seung Sung"

Objective: The trend in the initial severity of aneurysmal subarachnoid hemorrhage (SAH) is unclear. This study aimed to evaluate whether there was an improvement in the initial severity of SAH over time.

Methods: From January 1, 2005, to December 31, 2020, we identified patients who visited the emergency department of our institution with SAH due to intracranial aneurysm rupture.

View Article and Find Full Text PDF

In this report, we merge block copolymers with vitrimers in an effort to realize the prospect of higher-order, nanoscale control over associative cross-link exchange and flow. We show the use of controlled polymerization as a vital tool to understand fundamental structure-property effects through the precise control of polymer architecture and molecular weight. Vitrimers derived from self-assembling block copolymers exhibit superior resistance to macroscopic deformation in comparison to their analogs generated from statistical copolymers.

View Article and Find Full Text PDF

The optimization of ionic conductivity and lithium-ion battery stability can be achieved by independently tuning the ion transport and mechanical robustness of block polymer (BP) electrolytes. However, the ionic conductivity of BP electrolytes is inherently limited by the covalent attachment of the ionically conductive block to the mechanically robust block, among other factors. Herein, the BP electrolyte polystyrene--poly(oligo-oxyethylene methacrylate) [PS--POEM] was blended with POEM homopolymers of varying molecular weights.

View Article and Find Full Text PDF

Solid-state conducting polymers usually have highly conjugated macromolecular backbones and require intentional doping in order to achieve high electrical conductivities. Conversely, single-component, charge-neutral macromolecules could be synthetically simpler and have improved processibility and ambient stability. We show that poly(4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), a nonconjugated radical polymer with a subambient glass transition temperature, underwent rapid solid-state charge transfer reactions and had an electrical conductivity of up to 28 siemens per meter over channel lengths up to 0.

View Article and Find Full Text PDF

Background: The purpose of this study was to identify the epidemiologic characteristics of hand tendon injuries in children and to compare these with those of adults.

Methods: This retrospective study was conducted on acute traumatic tendon injuries of the hand treated at our institution from 2005 to 2013, based on medical records and X-ray findings. Age, sex, hand injured, mechanism of injury, tendons and zones injured, number of affected digits, and comorbidities and complications were analyzed.

View Article and Find Full Text PDF

Folds, highly deformed structures, have received extensive attention for their nonlinear responses due to a large strain on soft matters. To investigate the folding phenomena, here, we exploit residual tensile stress during metal deposition, which is large enough to compress a thin film coating and introduce a photocurable viscous fluid to decrease the resistance of the substrate against compressive stress. The system has the advantages of the abilities for freezing the highly deformed surfaces by post-UV exposure to the UV-crosslinkable substrate and manipulating the substrate effect by controlling the thickness of the substrate.

View Article and Find Full Text PDF

Electrostatic force microscopy (EFM) is often used for nanoscale dielectric spectroscopy, the measurement of local dielectric properties of materials as a function of frequency. However, the frequency range of atomic force microscopy (AFM)-based dielectric spectroscopy has been limited to a few kilohertz by the resonance frequency and noise of soft microcantilevers used for this purpose. Here, we boost the frequency range of local dielectric spectroscopy by 3 orders of magnitude from a few kilohertz to a few megahertz by developing a technique that exploits the high resonance frequency and low thermal noise of ultrasmall cantilevers (USCs).

View Article and Find Full Text PDF

In polymer-based ferroelectric diodes, films are composed of a semiconducting polymer and a ferroelectric polymer blend sandwiched between two metal electrodes. In these thin films, the ferroelectric phase serves as the memory retention medium while the semiconducting phase serves as the pathway to read-out the memory in a nondestructive manner. As such, having distinct phases for the semiconducting and ferroelectric phases have proven critical to device performance.

View Article and Find Full Text PDF

Partial or complete absence of the posterior arch of the atlas is a well-documented anomaly but a relatively rare condition. This condition is usually asymptomatic so most are diagnosed incidentally. There have been a few documented cases of congenital defects of the posterior arch of the atlas combined with atlantoaxial subluxation.

View Article and Find Full Text PDF

A strategy to fabricate nanostructured poly(3-hexylthiophene) (P3HT) films for organic photovoltaic (OPV) cells by a direct transfer method from a reusable soft replica mold is presented. The flexible polyfluoropolyether (PFPE) replica mold allows low-pressure and low- temperature process condition for the successful transfer of nanostructured P3HT films onto PEDOT/PSS-coated ITO substrates. To reduce the fabrication cost of masters in large area, we employed well-ordered anodic aluminum oxide (AAO) as a template.

View Article and Find Full Text PDF

We present the mold design rules for assuring residual layer-free patterning in thermal imprint processes. Using simple relations for mass balance, structural stability, and work of adhesion, we derive the conditions with respect to the given single or multigeometrical feature of the mold, which are compared with simple thermal imprint experiments using soft imprint molds. Our analysis could serve as a guideline for designing the optimum mold geometry and selecting mold material in residual layer-free thermal imprint processes.

View Article and Find Full Text PDF

Displacement and inappropriate treatment of a proximal phalangeal neck fracture may result in malunion of the fracture with consequent loss of motion and gross deformity, especially in children. We performed a retrospective study of twenty-four patients who had undergone operative treatment for a proximal phalangeal neck fracture, with a mean follow-up evaluation of 14 months (range: 12-30 months). We analyzed the types of fractures, their causes, operative treatments, complications, and functional outcomes.

View Article and Find Full Text PDF

The Epstein-Barr virus (EBV) SM protein is a posttranscriptional regulator of cellular and viral gene expression that binds and stabilizes target mRNAs and shuttles from nucleus to cytoplasm. SM enhances expression of several EBV genes required for lytic replication and is essential for virion production. SM increases accumulation of specific mRNAs but also inhibits expression of several intron-containing transcripts.

View Article and Find Full Text PDF

The popular recreational drug, 3,4-methylenedioxymethamphetamine (MDMA) exerts its actions in part via blockade of serotonin and dopamine reuptake. Many animal and human studies have demonstrated long-lasting reductions in measures of central nervous system (CNS) serotonin function following MDMA administration. One emerging role of serotonin function in the CNS is a positive trophic effect via stimulation of intracellular signaling pathways and trophic factors.

View Article and Find Full Text PDF

Alterations in brain high-energy phosphate metabolism, determined by in vivo magnetic resonance spectroscopy (MRS), have been reported in subjects with a number of brain disorders including major depression, schizophrenia, and substance abuse. It is not clear to what extent these changes can be modified by pharmacological or nutritional means. To address this possibility, we evaluated changes in brain chemistry that were associated with oral creatine (Cr) administration.

View Article and Find Full Text PDF

Viruses utilize numerous mechanisms to counteract the host's immune response. Interferon production is a major component of the host antiviral response. Many viruses, therefore, produce proteins or RNA molecules that inhibit interferon-induced signal transduction pathways and their associated antiviral effects.

View Article and Find Full Text PDF

The purpose of this study was to evaluate the reliability and validity of the Korean version of the Temperament and Character Inventory (TCI), a self-report questionnaire based on Cloninger's biosocial model of personality. The TCI was translated into Korean and administered to 851 Korean college students. A test-retest study of the TCI was conducted across a 3-month interval with 130 subjects.

View Article and Find Full Text PDF