Publications by authors named "Kyung Jin Ahn"

Two-dimensional boron nitride (BN) insulating layers gained attracted attention for their high-performance memristive behavior. However, crystalline hexagonal BN (h-BN) suffers from a high initial SET voltage due to a lack of boron vacancies, while vacancy-rich amorphous BN (a-BN) exhibits significant current fluctuations during RESET due to stochastically formed filaments. In this work, an amorphous-crystalline mixture BN (acm-BN) via low-pressure chemical vapor deposition to achieve balanced resistive switching, offering low SET voltage and improved RESET stability is synthesized.

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Background: This study aimed to evaluate the progress of treatment with intensive targeted therapy in high-risk pulmonary arterial hypertension (PAH) patients and focused on setting an appropriate hemodynamic target of pulmonary vascular resistance (PVR) ≤4 Wood units (WU) and mean pulmonary arterial pressure (mPAP) ≤ 40 mmHg.

Methods: We retrospectively evaluated high-risk PAH patients who were administered treprostinil at a single tertiary pulmonary hypertension center between January 2020 and December 2022. Echocardiography, right heart catheterization, 6-minute walk distance (6MWD), and blood tests were obtained 6 and 12 months after the initiation of parenteral treprostinil administration.

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Refractoriness to initial chemotherapy and relapse after remission are the main obstacles to curing T cell acute lymphoblastic leukemia (T-ALL). While tumor heterogeneity has been implicated in treatment failure, the cellular and genetic factors contributing to resistance and relapse remain unknown. Here we linked tumor subpopulations with clinical outcome, created an atlas of healthy pediatric hematopoiesis and applied single-cell multiomic analysis to a diverse cohort of 40 T-ALL cases.

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Galactic cosmic radiation (GCR) is an unavoidable risk to astronauts that may affect mission success. Male rodents exposed to 33-beam-GCR (33-GCR) show short-term cognitive deficits but reports on female rodents and long-term assessment are lacking. We asked: What are the longitudinal behavioral effects of 33-GCR on female mice? Also, can an antioxidant/anti-inflammatory compound (CDDO-EA) mitigate the impact of 33-GCR? Mature (6-month-old) C57BL/6J female mice received CDDO-EA (400 μg/g of food) or a control diet (vehicle, Veh) for 5 days and Sham-irradiation (IRR) or whole-body 33-GCR (0.

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Background And Objectives: This study aimed to analyze the outcomes of Fontan surgery in the Republic of Korea, as there were only a few studies from Asian countries.

Methods: The medical records of 1,732 patients who underwent Fontan surgery in 10 cardiac centers were reviewed.

Results: Among them, 1,040 (58.

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Introduction: The long-term effects of fenestration in patients with Fontan circulation remain unclear. We aim to evaluate the fenestration impact on early and late outcomes in patients with extracardiac Fontan (ECF) using a propensity score matching analysis.

Methods: We performed an extensive retrospective multicenter clinical data review of the Korean Fontan registry and included 1,233 patients with surgical ECF (779 fenestrated, 454 non-fenestrated).

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Non-hematopoietic cells are essential contributors to hematopoiesis. However, heterogeneity and spatial organization of these cells in human bone marrow remain largely uncharacterized. We used single-cell RNA sequencing (scRNA-seq) to profile 29,325 non-hematopoietic cells and discovered nine transcriptionally distinct subtypes.

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Article Synopsis
  • The bone marrow is crucial for blood production, with non-hematopoietic cells playing key roles, yet their organization in humans has been underexplored due to technical difficulties.
  • Using advanced techniques like single-cell RNA sequencing, researchers characterized 29,325 bone marrow cells and identified nine distinct cellular subtypes.
  • Their findings revealed specific niches for cell development in healthy and leukemia-affected samples, providing a detailed multiomic atlas of human bone marrow that can aid future studies on blood cell formation and interactions.
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Pediatric high-grade glioma (pHGG) is an incurable central nervous system malignancy that is a leading cause of pediatric cancer death. While pHGG shares many similarities to adult glioma, it is increasingly recognized as a molecularly distinct, yet highly heterogeneous disease. In this study, we longitudinally profiled a molecularly diverse cohort of 16 pHGG patients before and after standard therapy through single-nucleus RNA and ATAC sequencing, whole-genome sequencing, and CODEX spatial proteomics to capture the evolution of the tumor microenvironment during progression following treatment.

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The initiation and progression of cancer are intricately linked to the tumor microenvironment (TME). Understanding the function of specific cancer-TME interactions poses a major challenge due in part to the complexity of the in vivo microenvironment. Here we predict cancer-TME interactions from single cell transcriptomic maps of both human colorectal cancers (CRCs) and mouse CRC models, ask how these interactions are altered in human tumor organoid (tumoroid) cultures, and functionally recapitulate human myeloid-carcinoma interactions in vitro.

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Refractoriness to initial chemotherapy and relapse after remission are the main obstacles to cure in T-cell Acute Lymphoblastic Leukemia (T-ALL). Biomarker guided risk stratification and targeted therapy have the potential to improve outcomes in high-risk T-ALL; however, cellular and genetic factors contributing to treatment resistance remain unknown. Previous bulk genomic studies in T-ALL have implicated tumor heterogeneity as an unexplored mechanism for treatment failure.

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Background And Objectives: Although long QT syndrome (LQTS) is a potentially life-threatening inherited cardiac channelopathy, studies documenting the long-term clinical data of Korean patients with LQTS are scarce.

Methods: This retrospective cohort study included 105 patients with LQTS (48 women; 45.7%) from a single tertiary center.

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Background And Objectives: Protein-losing enteropathy (PLE) is a devastating complication after the Fontan operation. This study aimed to investigate the clinical characteristics, treatment response, and outcomes of Fontan-associated PLE.

Methods: We reviewed the medical records of 38 patients with Fontan-associated PLE from 1992 to 2018 in 2 institutions in Korea.

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Pulmonary arterial hypertension (PAH) is the second most common lung complication in antiphospholipid syndrome (APS) patients. However, the concurrent development of APS-related nonthrombotic PAH is rarely reported. Lack of awareness for group 1 PAH in APS patient may contribute to underdiagnosis of this condition.

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Pulmonary hypertension is a rare and progressive illness with a devastating prognosis. Promising research efforts have advanced the understanding and recognition of the pathobiology of pulmonary hypertension. Despite remarkable achievements in terms of improving the survival rate, reducing disease progression, and enhancing quality of life, pulmonary arterial hypertension (PAH) is not completely curable.

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Purpose: Heart failure (HF) poses significant morbidity and mortality. Recently, the ventriculo-vascular coupling index (VVI) was introduced as an independent prognostic factor reflective of the overall cardiovascular performance index in HF. We aimed to determine the effectiveness of force-titration of valsartan on VVI values in HF patients.

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Two-dimensional transition metal dichalcogenides (TMDs) offer numerous advantages over silicon-based application in terms of atomically thin geometry, excellent opto-electrical properties, layer-number dependence, band gap variability, and lack of dangling bonds. The production of high-quality and large-scale TMD films is required with consideration of practical technology. However, the performance of scalable devices is affected by problems such as contamination and patterning arising from device processing; this is followed by an etching step, which normally damages the TMD film.

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Pulmonary arterial hypertension (PAH) is known as one of diseases with the worst prognosis. Recently, targeted PAH drugs have been developed and approved for use; therefore, the treatment strategy and goals have changed, and the prognosis has improved over two decades. We reviewed the case of a female who showed the natural disease course of heritable PAH in treatment with the targeted PAH drugs under the Korean Health Insurance policy.

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Background: Patients with repaired congenital heart disease (CHD) can have both depolarization and repolarization abnormalities. A coexisting long QT syndrome (LQTS) may cause electrical instability in these patients; however, diagnosing LQTS is difficult owing to intraventricular conduction delay or paced rhythm after the operation. We report on six patients diagnosed with LQTS after CHD repair.

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Long QT syndrome (LQTS) is an inherited cardiac disease characterized by a prolonged heart rate-corrected QT (QTc) interval. We investigated the genetic causes in patients with prolonged QTc intervals who were negative for pathogenic variants in three major LQTS-related genes (KCNQ1, KCNH2, and SCN5A). Molecular genetic testing was performed using a panel including 13 LQTS-related genes and 67 additional genes implicated in other cardiac diseases.

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Midaortic syndrome (MAS) is a rare vascular disease that commonly causes renovascular hypertension. The lumen of the abdominal aorta narrows and the ostia of the branches show stenosis. MAS is associated with diminished pulses in the lower extremities compared with the upper extremities, severe hypertension with higher blood pressure in the upper rather than lower extremities, and an abdominal bruit.

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Purpose: Alagille syndrome is a complex hereditary disorder that is associated with cardiac, hepatic, skeletal, ocular, and facial abnormalities. Mutations in the Notch signaling pathway, such as in JAG1 and NOTCH2, play a key role in embryonic development. A cardiac or hepatic presentation is a critical factor for determining the prognosis.

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Purpose: Kabuki syndrome is a multiple congenital malformation syndrome, with characteristic facial features, mental retardation, and skeletal and congenital heart anomalies. However, the cardiac anomalies are not well described in the Korean population. We analyzed the cardiac anomalies and clinical features of Kabuki syndrome in a single tertiary center.

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