Publications by authors named "Yebin Ahn"

Three-dimensional structured silicon solar cells have demonstrated remarkable potential for enhanced light absorption, yet their practical implementation remains limited by mechanical fragility. While microwire architectures offer superior optical properties through effective light scattering and radial junction formation, their high aspect ratio creates significant mechanical stress at the wire-substrate interface, leading to structural failure under physical strain. Here, we present conically etched microhole arrays (CEMA) that fundamentally address this challenge by inverting the conventional microwire concept while maintaining its optical and electrical advantages.

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Metal-assisted chemical etching (MaCE) has emerged as a promising technique for fabricating silicon nanostructures, yet the presence of anomalous isotropic etching poses significant challenges for precise dimensional control. Here, it is demonstrated that catalyst morphology, particularly its aspect ratio, plays a crucial role in determining etching directionality. Through systematic investigation of the initial stages of MaCE, it is revealed that significant undercutting occurs within seconds of etching initiation, persisting across all solution compositions.

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Objectives: Tic disorders are highly heritable; however, growing evidence suggests that environmental factors play a significant role in their pathogenesis. Studies on these factors have been inconsistent, with conflicting results. Therefore, this study aimed to examine the associations of pre- and perinatal exposure to Tourette syndrome (TS) or chronic tic disorders (CTD) in Korean school-aged children.

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Objective: Underconnectivity in the resting brain is not consistent in autism spectrum disorder (ASD). However, it is known that the functional connectivity of the default mode network is mainly decreased in childhood ASD. This study investigated the brain network topology as the changes in the connection strength and network efficiency in childhood ASD, including the early developmental stages.

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In this review, we provide information about the etiology, risk factors, and clinical presentations of maltreatment to help clinicians better understand child abuse and neglect. Child maltreatment is a major global health challenge that can result in severe consequences. Abused and neglected children are likely to develop psychiatric disorders, such as major depressive disorder, anxiety disorder, and posttraumatic stress disorder.

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Background: Humans are exposed to a mixture of metals during their lifetime; however, evidence of neurotoxicity of such mixtures in critical time windows is still insufficient. We aimed to elucidate the associations of four metals mixture across multiple time points with children's intelligence quotient (IQ) in a prospective cohort study.

Methods: Prenatal exposure and exposure at age 4 and 6 years to four types of blood metals, namely lead, mercury, cadmium, and manganese were quantified in 502 pregnant women and their children who participated in the Environment and Development Cohort study.

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Objectives: This study was conducted to investigate the reliability and validity of the Korean version of the DSM-5 Level 2 Cross-Cutting Symptom Measure-inattention [Swanson, Nolan and Pelham, version IV (SNAP-IV)] and anger [Patient-Reported Outcome Measurement Information System (PROMIS) Anger] for parents and guardians of children aged 6-17 years.

Methods: We included 104 children and adolescents diagnosed with attention-deficit/hyperactivity disorder (ADHD), ADHD with anxiety and depression, depressive disorder, anxiety disorder, and tic disorder with somatic symptoms (ADHD=41, depression=9, anxiety=14, ADHD+anxious depression=11, tic+somatic symptoms=29). Their ages ranged from 8 years to 15 years.

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Objective: The purpose of this study is to identify the demographic variables that are affecting performances on the Logical Memory (LM) subtest included in the Korean version of the Wechsler Memory Scale (WMS)-IV and to provide normative data on the LM subtest for the middle-age and elderly Korean people.

Methods: The participants were 435 non-demented adults aging from 50 to 90 and with the educational level ranging from 0 to 21 years.

Results: Age and education were found to be significantly associated with performance on the LM subtest, while gender effect was not statistically significant.

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Parkinson's disease (PD) is the second most common neurodegenerative disorder. Although its major manifestation is motor symptoms, resulting from the loss of dopaminergic neurons in the substantia nigra, psychiatric symptoms, such as depression, anxiety, hallucination, delusion, apathy and anhedonia, impulsive and compulsive behaviors, and cognitive dysfunction, may also manifest in most patients with PD. Given that the quality of life - and the need for institutionalization - is so highly dependent on the psychiatric well-being of patients with PD, psychiatric symptoms are of high clinical significance.

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Unlabelled: Targeted molecular therapy has yielded remarkable outcomes in certain cancers, but specific therapeutic targets remain elusive for many others. As a result of two independent RNA interference (RNAi) screens, we identified pathway dependence on a member of the Janus-activated kinase (JAK) tyrosine kinase family, TYK2, and its downstream effector STAT1, in T-cell acute lymphoblastic leukemia (T-ALL). Gene knockdown experiments consistently showed TYK2 dependence in both T-ALL primary specimens and cell lines, and a small-molecule inhibitor of JAK activity induced T-ALL cell death.

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The oncogenic transcription factor TAL1/SCL is aberrantly expressed in over 40% of cases of human T cell acute lymphoblastic leukemia (T-ALL), emphasizing its importance in the molecular pathogenesis of T-ALL. Here we identify the core transcriptional regulatory circuit controlled by TAL1 and its regulatory partners HEB, E2A, LMO1/2, GATA3, and RUNX1. We show that TAL1 forms a positive interconnected autoregulatory loop with GATA3 and RUNX1 and that the TAL1 complex directly activates the MYB oncogene, forming a positive feed-forward regulatory loop that reinforces and stabilizes the TAL1-regulated oncogenic program.

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To identify dysregulated pathways in distinct phases of NOTCH1-mediated T-cell leukemogenesis, as well as small-molecule inhibitors that could synergize with or substitute for gamma-secretase inhibitors (GSIs) in T-cell acute lymphoblastic leukemia (T-ALL) therapy, we compared gene expression profiles in a Notch1-induced mouse model of T-ALL with those in human T-ALL. The overall patterns of NOTCH1-mediated gene expression in human and mouse T-ALLs were remarkably similar, as defined early in transformation in the mouse by the regulation of MYC and its target genes and activation of nuclear factor-kappaB and PI3K/AKT pathways. Later events in murine Notch1-mediated leukemogenesis included down-regulation of genes encoding tumor suppressors and negative cell cycle regulators.

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A growing body of evidence indicates that early mitotic inhibitor 1 (Emi1) is essential for genomic stability, but how this function relates to embryonic development and cancer pathogenesis remains unclear. We have identified a zebrafish mutant line in which deficient emi1 gene expression results in multilineage hematopoietic defects and widespread developmental defects that are p53 independent. Cell cycle analyses of Emi1-depleted zebrafish or human cells showed chromosomal rereplication, and metaphase preparations from mutant zebrafish embryos revealed rereplicated, unsegregated chromosomes and polyploidy.

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To more comprehensively assess the pathogenic contribution of the PTEN-PI3K-AKT pathway to T-cell acute lymphoblastic leukemia (T-ALL), we examined diagnostic DNA samples from children with T-ALL using array comparative genomic hybridization and sequence analysis. Alterations of PTEN, PI3K, or AKT were identified in 47.7% of 44 cases.

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Neuroblastoma, an embryonal tumour of the peripheral sympathetic nervous system, accounts for approximately 15% of all deaths due to childhood cancer. High-risk neuroblastomas are rapidly progressive; even with intensive myeloablative chemotherapy, relapse is common and almost uniformly fatal. Here we report the detection of previously unknown mutations in the ALK gene, which encodes a receptor tyrosine kinase, in 8% of primary neuroblastomas.

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