Publications by authors named "Seong-Yeon Kim"

The wide band gap perovskite solar cells (PSCs) have attracted considerable attention for their great potential as top cells in high efficiency tandem cell application. However, the photovoltaic performance and stability of PSCs are constrained by nonradiative recombination, primarily stemming from defects within the bulk and at the interface of charge transport layer/perovskite and phase segregation. In this study, we systematically investigated the effects of 2-thiopheneethylammonium chloride (TEACl) on a wide band gap (∼1.

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The chalcopyrite Cu(In,Ga)(S,Se) (CIGSSe) solar cell with a low band gap is a promising candidate for use as the bottom cell in high-efficiency tandem solar cells. In this study, we investigated narrow band gap CIGSSe solar cells, both with and without alkali treatment. The CIGSSe absorbers were fabricated using aqueous spray pyrolysis in an air environment, with the precursor solution prepared by dissolving constituent metal salts.

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Background: Adolescence to young adulthood is a critical developmental period that determines lifelong patterns of tobacco use. We examined the longitudinal trajectories of tobacco use, and risk factors for its use, and explored the association between the trajectories of mobile phone dependency and smoking throughout the life-course among adolescents and young adults.

Methods: Data of 1,723 subjects (853 boys and 870 girls) were obtained from six waves of the Korean Children and Youth Panel Survey (mean age = 13.

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Article Synopsis
  • Neuromorphic devices aim to address the limitations of traditional von Neumann computer systems for AI by enhancing hardware integration.
  • A new segmented transistor design, compatible with CMOS technology, enhances the linearity of potentiation and depression in artificial synapses using Schottky junctions and a double-layered nitride.
  • This innovation may advance the mass production of silicon-based synaptic devices, improving their speed and efficiency for future AI applications.
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Background: Salivary cortisol is routinely used as a diagnostic test for Cushing syndrome. The diagnostic use of salivary cortisol for adrenal insufficiency (AI), however, is less established. We aimed to investigate the utility of morning basal and adrenocorticotropic hormone-stimulated salivary cortisol in diagnosing AI in Korean adults.

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Copper is a low-cost material compared to silver and gold, having high reflectivity in the near infrared spectral range as well as good electrical and thermal conductivity. Its properties make it a good candidate for metal-based low-cost multilayer thin-film devices and optical components. However, its high reflectance in the devices is reduced because copper is easily oxidized.

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Since 2015, universal comprehensive school-based tobacco control programs have been provided in all primary and secondary schools in Korea. This study explored the association of school-level tobacco control with adolescent smoking, and the interactions to investigate whether gender moderates the impact of school tobacco control programs and school-level norms. Both school- and individual-level data were drawn from the 2015 School-Based Tobacco Prevention Program Survey.

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We fabricated Cu(In,Ga)(S,Se) (CIGSSe) solar cells using aqueous spray based deposition, which is inexpensive and covers a large area. To apply the sprayed film to a photoabsorber of a solar cell, post-sulfo-selenization was carried out. Through the sulfo-selenization process, we were able to fabricate various S-alloyed CIGSSe films from S/(S + Se) = 0 (S-0.

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A diverse S/(S + Se) ratio of CuZnSn(S,Se) (CZTSSe) thin-film solar cells is derived by the water-based spray pyrolysis approach. By fine-tuning the S/(S + Se) ratio, base CZTSSe device efficiency has significantly improved from 7.02 to 10.

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Although a bipedicled deep inferior epigastric artery perforator (DIEP) flap is widely accepted for slim patients with large breasts, we suggest DIEP flap-based breast reconstruction in which the superficial inferior epigastric artery (SIEA) is supercharged to the branch of thoracodorsal vessel as an alternative, which has not previously been well described. We report the case of a 48-year-old breast cancer patient who had a normal body mass index of 23.01 and relatively thin abdominal tissue, with large and ptotic (grade II ptosis) breasts.

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Owing to their simple and low-cost architecture, extended-gate biosensors based on the combination of a disposable sensing part and a reusable transducer have been widely utilized for the label-free electrical detection of chemical and biological species. Previous studies have demonstrated that sensitive and selective detection of ions and biomolecules can be achieved by controlled modification of the sensing part with an ion-selective membrane and receptors of interest. However, no systematic studies have been performed on the impact of the transducer on sensing performance.

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Background: Mallet fracture can easily occur during sports activities or in daily life; however, the principles and methods of treatment for such fractures remain debated. Among the surgical treatments, various methods of closed reduction have been proposed. We treated patients with the extension block method (EBM) and the direct pinning method (DPM), and then compared the results.

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Background: Primary adrenal insufficiency (PAI) is a rare, potentially life-threatening condition. There are few Korean studies on PAI, and most have had small sample sizes. We aimed to examine the etiology, clinical characteristics, treatment, and mortality of PAI in Korean patients.

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A physical unclonable function (PUF) device using a nano-electromechanical (NEM) switch was demonstrated. The most important feature of the NEM-switch-based PUF is its use of stiction. Stiction is one of the chronic problems associated with micro- and nano-electromechanical system (MEMS/NEMS) devices; however, here, it was utilized to intentionally implement a PUF for hardware-based security.

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Objective: Recently, the European Society of Endocrinology (ESE), in collaboration with the European Network for the Study of Adrenal Tumors (ENSAT), asserted that adrenal incidentalomas (AIs) <4 cm and ≤10 Hounsfield units (HU) do not require further follow-up imaging. To validate the clinical application of the follow-up strategies suggested by the 2016 ESE-ENSAT guidelines, we explored the clinical characteristics and natural course of AIs in a single center over 13 years.

Design And Methods: This retrospective cohort study included a total of 1149 patients diagnosed with AIs between 2000 and 2013 in a single tertiary center.

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Purpose: Dopamine agonist (DA) therapy is recommended as the first-line treatment for prolactinomas. However, it requires long treatment duration, and a high recurrence rate after DA withdrawal has been reported. We aimed to elucidate the predictors for long-term remission following DA withdrawal and propose the best candidates who can achieve complete remission after DA withdrawal.

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An adrenal incidentaloma is an adrenal mass found in an imaging study performed for other reasons unrelated to adrenal disease and often accompanied by obesity, diabetes, or hypertension. The prevalence and incidence of adrenal incidentaloma increase with age and are also expected to rise due to the rapid development of imaging technology and frequent imaging studies. The Korean Endocrine Society is promoting an appropriate practice guideline to meet the rising incidence of adrenal incidentaloma, in cooperation with the Korean Adrenal Gland and Endocrine Hypertension Study Group.

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Objective: Endoscopic transsphenoidal surgery has recently been introduced in pituitary surgery. We investigated outcomes and complications of endoscopic surgery in 2 referral centers in Korea.

Methods: We enrolled 134 patients with acromegaly (microadenomas, n = 15; macroadenomas, n = 119) who underwent endoscopic transsphenoidal surgery at Seoul National University Hospital (n = 74) and Samsung Medical Center (n = 60) between January 2009 and March 2016.

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Patients with aldosterone-producing adenomas are treated using surgery, and patients with idiopathic hyperaldosteronism receive medical treatment using mineralocorticoid receptor antagonists (MRAs). However, the outcomes of surgical and medical treatment for primary aldosteronism (PA) remain unclear. Therefore, we compared the outcomes of surgical and medical treatment for PA and aimed to identify a specific subgroup that might benefit from medical treatment.

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Objective: Many malignant tumors initially appear benign but subsequently exhibit extensive metastases. Early identification of malignant pheochromocytomas and paragangliomas (PPGLs) before metastasis is important for improved prognosis. However, there are no robust prognostic indices of recurrence and malignancy.

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Purpose: Hypopituitary patients have a reduced life expectancy owing to cardiovascular events. We investigated the prevalence of metabolic syndrome in hypopituitary patients for a follow-up period of at least 1 year in comparison with an age- and sex-matched nationwide control group.

Methods: A total of 515 patients with hypopituitarism who visited Seoul National University Hospital between January 2000 and December 2010 were included.

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Aims/introduction: Dipeptidyl peptidase-4 inhibitors might have pleiotropic protective effects on cardiovascular disease (CVD), in contrast to sulfonylureas. Therefore, we compared various CVD risk factors between vildagliptin and glimepiride.

Materials And Methods: We carried out a randomized, prospective and crossover trial.

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Article Synopsis
  • A new lily-type lectin gene (RbLTL) was cloned from rock bream, revealing a protein of 117 amino acids with essential structural features like a B-lectin domain and d-mannose binding sites.
  • RbLTL mRNA is mainly expressed in the gills, with lower levels in the intestine, and its expression increases over time in fertilized eggs before decreasing after 36 hours.
  • The study suggests that RbLTL plays a significant role in the innate immune response of rock bream against pathogens like Streptococcus iniae and Edwardsiella tarda.
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Background: The identification of a marker for hypoglycemia could help patients achieve strict glucose control with a lower risk of hypoglycemia. 1,5-Anhydro-D-glucitol (1,5-AG) reflects postprandial hyperglycemia in patients with well-controlled diabetes, which contributes to glycemic variability. Because glycemic variability is related to hypoglycemia, we aimed to evaluate the value of 1,5-AG as a marker of hypoglycemia.

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