A seed-mediated growth of gold nanoparticles inside carbon nanotube fibers for fabrication of multifunctional nanohybrid fibers with enhanced mechanical and electrical properties

Kim, Young-Jin,Park, Junbeom,Jeong, Hyeon Su,Park, Min,Baik, Seulki,Lee, Dong Su,Rho, Heesuk,Kim, Hyungjun,Lee, Joong Hee,Kim, Seung-Min,Kim, Young-Kwan The Royal Society of Chemistry 2019 Nanoscale Vol.11 No.12

<P>The seed-mediated growth strategy of Au nanoparticles (Au NPs) inside carbon nanotube (CNT) fibers is demonstrated to greatly improve their mechanical and electrical properties and provide a function for catalytic applications. The resulting Au NP@CNT nanocomposite fibers exhibit 100% knot efficiency, catalytic activity and considerably enhanced modulus, tensile strength, and electrical conductivity from 7 GPa, 109 MPa and 1300 S cm<SUP>−1</SUP> to 24 GPa, 351 MPa and 3600 S cm<SUP>−1</SUP>, respectively. The enhancement mechanism is also revealed by systematic characterization and theoretical simulations.</P>

Combined Skin Moisturization of Liposomal Serine Incorporated in Hydrogels Prepared with Carbopol ETD 2020, Rhesperse RM 100 and Hyaluronic Acid

Kim, Hyeongmin,Ro, Jieun,Barua, Sonia,Hwang, Deuk Sun,Na, Seon-Jeong,Lee, Ho Sung,Jeong, Ji Hoon,Woo, Seulki,Kim, Hyewon,Hong, Bomi,Yun, Gyiae,Kim, Joong-Hark,Yoon, Young-Ho,Park, Myung-Gyu,Kim, Jia,S The Korean Society of Pharmacology 2015 The Korean Journal of Physiology & Pharmacology Vol.19 No.6

We investigated the combined moisturizing effect of liposomal serine and a cosmeceutical base selected in this study. Serine is a major amino acid consisting of natural moisturizing factors and keratin, and the hydroxyl group of serine can actively interact with water molecules. Therefore, we hypothesized that serine efficiently delivered to the stratum corneum (SC) of the skin would enhance the moisturizing capability of the skin. We prepared four different cosmeceutical bases (hydrogel, oil-in-water (O/W) essence, O/W cream, and water-in-oil (W/O) cream); their moisturizing abilities were then assessed using a $Corneometer^{(R)}$. The hydrogel was selected as the optimum base for skin moisturization based on the area under the moisture content change-time curves (AUMCC) values used as a parameter for the water hold capacity of the skin. Liposomal serine prepared by a reverse-phase evaporation method was then incorporated in the hydrogel. The liposomal serine-incorporated hydrogel (serine level=1%) showed an approximately 1.62~1.77 times greater moisturizing effect on the skin than those of hydrogel, hydrogel with serine (1%), and hydrogel with blank liposome. However, the AUMCC values were not dependent on the level of serine in liposomal serine-loaded hydrogels. Together, the delivery of serine to the SC of the skin is a promising strategy for moisturizing the skin. This study is expected to be an important step in developing highly effective moisturizing cosmeceutical products.

Long-term depletion of cereblon induces mitochondrial dysfunction in cancer cells

( Seulki Park ),( Kidae Kim ),( Keeok Haam ),( Hyun Seung Ban ),( Jung-ae Kim ),( Byoung Chul Park ),( Sung Goo Park ),( Sunhong Kim ),( Jeong-hoon Kim ) 생화학분자생물학회(구 한국생화학분자생물학회) 2021 BMB Reports Vol.54 No.6

Cereblon (CRBN) is a multi-functional protein that acts as a substrate receptor of the E3 ligase complex and a molecular chaperone. While CRBN is proposed to function in mitochondria, its specific roles are yet to be established. Here, we showed that knockdown of CRBN triggers oxidative stress and calcium overload in mitochondria, leading to disruption of mitochondrial membrane potential. Notably, long-term CRBN depletion using PROteolysis TArgeting Chimera (PROTAC) induced irreversible mitochondrial dysfunction, resulting in cell death. Our collective findings indicate that CRBN is required for mitochondrial homeostasis in cells. [BMB Reports 2021; 54(6): 305-310]

Clinical Characteristics of Nocardiosis: a Multicenter Retrospective Study in Korea

Kim Seulki,Shi Hye Jin,Jeon Cheon-Hoo,Kim Sun Bean,Yi Jongyoun,Kim A Reum,Kim Kye-Hyung,Lim Seungjin 대한감염학회 2023 Infection and Chemotherapy Vol.55 No.4

Background: Nocardiosis is a rare, but potentially life-threatening condition. It is difficult to diagnose, and bacterial culture identification can be time consuming. We investigated the characteristics of nocardiosis and the suitability of the treatment approach in Korea. Materials and Methods: This retrospective study was conducted at 5 medical institutions between 2011 and 2021. We reviewed the medical records of patients with microbiologically confirmed nocardiosis. Appropriate antibiotic selection was defined as follows: (1) selecting antibiotics according to the species, (2) if the species of Nocardia was unknown, trimethoprim-sulfamethoxazole-based therapy or linezolid-based therapy was administered, and (3) selection of antibiotics using the antibiotic susceptibility test. The appropriate treatment periods for antibiotics were defined as treatment maintained from 3 to 12 months, depending on involvement of the organs. Descriptive analysis and Fisher exact test were used. Statistical significance was set at P-values of <0.05. Results: Thirty patients were enrolled. Of these patients, 18 (60.0%) were male. The median age was 70.5 years. Among the diagnosed patients, 12 (40.0%) had an immunocompromised status. Eight (30.0%) patients received optimal treatment for the appropriate treatment period. Appropriate dosing duration was observed in 3 of the 12(25.0%) immunocompromised patients. There was no significant difference between the presence or absence of immunosuppression and the adequacy of treatment for nocardiosis (P = 1.000). Skin and soft tissue (14 patients) were most frequently involved in this study. Nocardia species (spp.) were isolated from culture at a median of 6.0 days. There were 7 cases with N. farcinica (23.3%). Conclusion: We found that 60.0% of the patients with nocardiosis did not have an immunocompromised status. Further, 26.7% of the total patients received adequate treatment for nocardiosis. The reasons for suboptimal management of nocardiosis in Korea are presumed to be diagnostic difficulties, lack of awareness about nocardiosis, and difficulties in selecting antibiotics for Nocardia spp. among clinicians. The lack of antibiotic susceptibility tests for Nocardia spp. could be the source of these problems. Nocardiosis should be suspected in cases of recurrent infections with skin and soft tissue, musculoskeletal, or respiratory system involvement with or without an immunocompromised status. Clinical microbiological support is required for the diagnosis and selection of antibiotics in Korea. High clinical index of suspicion and clinical microbiological support are required for the accurate diagnosis of nocardiosis in Korea.

초 · 중등 AI 교육을 위한 데이터셋 분석 및 활용 제안

김슬기(Seulki Kim),전용주(Yongju Jeon),이현아(Hyunah Lee),김영애(Youngae Kim),김태영(Taeyoung Kim) 한국컴퓨터교육학회 2021 한국컴퓨터교육학회 학술발표대회논문집 Vol.25 No.1(A)

AI교육의 중요성 확대와 AI교육을 위한 데이터셋 분석에 대한 요구가 증대됨에 따라 초 · 중등 AI교육에 활용할 수 있는 데이터셋을 발굴하기 위해 국내 17개, 해외 8개의 데이터셋 제공 플랫폼을 분석하였으며, 교육활동에 활용할 수 있는 데표 대이터셋을 제안하였다. 또한, 다양한 데이터셋 전처리 방법들 중에 교육과정에 적절한 전처리 방법을 분석하고 학교급에 맞는 활동으로 제안하였다.

Carrier Lifetime Extension via the Incorporation of Robust Hole/Electron Blocking Layers in Bulk Heterojunction Polymer Solar Cells

Yoon, Youngwoon,Kim, Hyeong Jun,Cho, Chul-Hee,Kim, Seulki,Son, Hae Jung,Ko, Min-Jae,Kim, Honggon,Lee, Doh-Kwon,Kim, Jin Young,Lee, Wonmok,Kim, Bumjoon J.,Kim, BongSoo American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.1

<P>We report the achievement of a power conversion efficiency (PCE) improvement in P3HT:PCBM-based bulk-heterojunction type polymer solar cells using photocrosslinked P3HT (c-P3HT) as the electron blocking/hole extraction layer and titanium oxide nanoparticles (TiO<SUB>2</SUB>) as the hole blocking/electron extraction layer. Devices prepared with a 20 nm thick c-P3HT layer showed an improved PCE of 3.4% compared to devices prepared without the c-P3HT layer (PCE = 3.0%). This improvement was attributed to an extension in the carrier lifetime and an enhancement in the carrier mobility. The incorporation of the c-P3HT layer lengthened (by more than a factor of 2) the carrier lifetime and increased (by a factor of 5) the hole mobility. These results suggest that the c-P3HT layer not only prevented non-geminate recombination but it also improved carrier transport. The PCE was further improved to 4.0% through the insertion of a TiO<SUB>2</SUB> layer that acted as an effective hole-blocking layer at the interface between the photoactive layer and the cathode. This work demonstrates that the incorporation of solution-processable hole and electron blocking/extraction layers offers an effective means for preventing nongeminate recombination at the interfaces between a photoactive layer and an electrode in bulk-heterojunction-type polymer solar cells.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-1/am404381e/production/images/medium/am-2013-04381e_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am404381e'>ACS Electronic Supporting Info</A></P>

The Tumor Suppressor, p53, Negatively Regulates Non-Canonical NF-κB Signaling through miRNA-Induced Silencing of NF-κB-Inducing Kinase

Jang, Hanbit,Park, Seulki,Kim, Jaehoon,Kim, Jong Hwan,Kim, Seon-Young,Cho, Sayeon,Park, Sung Goo,Park, Byoung Chul,Kim, Sunhong,Kim, Jeong-Hoon Korean Society for Molecular and Cellular Biology 2020 Molecules and cells Vol.43 No.1

NF-κB signaling through both canonical and non-canonical pathways plays a central role in immune responses and inflammation. NF-κB-inducing kinase (NIK) stabilization is a key step in activation of the non-canonical pathway and its dysregulation implicated in various hematologic malignancies. The tumor suppressor, p53, is an established cellular gatekeeper of proliferation. Abnormalities of the TP53 gene have been detected in more than half of all human cancers. While the non-canonical NF-κB and p53 pathways have been explored for several decades, no studies to date have documented potential cross-talk between these two cancer-related mechanisms. Here, we demonstrate that p53 negatively regulates NIK in an miRNA-dependent manner. Overexpression of p53 decreased the levels of NIK, leading to inhibition of the non-canonical NF-κB pathway. Conversely, its knockdown led to increased levels of NIK, IKKα phosphorylation, and p100 processing. Additionally, miR-34b induced by nutlin-3 directly targeted the coding sequences (CDS) of NIK. Treatment with anti-miR-34b-5p augmented NIK levels and subsequent non-canonical NF-κB signaling. Our collective findings support a novel cross-talk mechanism between non-canonical NF-κB and p53.

Clinical Characteristics and Risk Factors for Mortality in Critical COVID-19 Patients Aged 50 Years or Younger During Omicron Wave in Korea: Comparison With Patients Older Than 50 Years of Age

Shi Hye Jin,Yang Jinyoung,Eom Joong Sik,Ko Jae-Hoon,Peck Kyong Ran,Kim Uh Jin,Jung Sook In,Kim Seulki,Seok Hyeri,Hyun Miri,Kim Hyun Ah,Kim Bomi,Joo Eun-Jeong,Cheong Hae Suk,Jun Cheon Hoo,Wi Yu Mi,Kim 대한의학회 2023 Journal of Korean medical science Vol.38 No.28

Background: The coronavirus disease 2019 (COVID-19) pandemic has caused the death of thousands of patients worldwide. Although age is known to be a risk factor for morbidity and mortality in COVID-19 patients, critical illness or death is occurring even in the younger age group as the epidemic spreads. In early 2022, omicron became the dominant variant of the COVID-19 virus in South Korea, and the epidemic proceeded on a large scale. Accordingly, this study aimed to determine whether young adults (aged ≤ 50 years) with critical COVID-19 infection during the omicron period had different characteristics from older patients and to determine the risk factors for mortality in this specific age group. Methods: We evaluated 213 critical adult patients (high flow nasal cannula or higher respiratory support) hospitalized for polymerase chain reaction-confirmed COVID-19 in nine hospitals in South Korea between February 1, 2022 and April 30, 2022. Demographic characteristics, including body mass index (BMI) and vaccination status; underlying diseases; clinical features and laboratory findings; clinical course; treatment received; and outcomes were collected from electronic medical records (EMRs) and analyzed according to age and mortality. Results: Overall, 71 critically ill patients aged ≤ 50 years were enrolled, and 142 critically ill patients aged over 50 years were selected through 1:2 matching based on the date of diagnosis. The most frequent underlying diseases among those aged ≤ 50 years were diabetes and hypertension, and all 14 patients who died had either a BMI ≥ 25 kg/m2 or an underlying disease. The total case fatality rate among severe patients (S-CFR) was 31.0%, and the S-CFR differed according to age and was higher than that during the delta period. The S-CFR was 19.7% for those aged ≤ 50 years, 36.6% for those aged > 50 years, and 38.1% for those aged ≥ 65 years. In multivariate analysis, age (odds ratio [OR], 1.084; 95% confidence interval [CI], 1.043–1.127), initial low-density lipoprotein > 600 IU/L (OR, 4.782; 95% CI, 1.584–14.434), initial C-reactive protein > 8 mg/dL (OR, 2.940; 95% CI, 1.042–8.293), highest aspartate aminotransferase > 200 IU/L (OR, 12.931; 95% CI, 1.691–98.908), and mechanical ventilation implementation (OR, 3.671; 95% CI, 1.294–10.420) were significant independent predictors of mortality in critical COVID-19 patients during the omicron wave. A similar pattern was shown when analyzing the data by age group, but most had no statistical significance owing to the small number of deaths in the young critical group. Although the vaccination completion rate of all the patients (31.0%) was higher than that in the delta wave period (13.6%), it was still lower than that of the general population. Further, only 15 (21.1%) critically ill patients aged ≤ 50 years were fully vaccinated. Overall, the severity of hospitalized critical patients was significantly higher than that in the delta period, indicating that it was difficult to find common risk factors in the two periods only with a simple comparison. Conclusion: Overall, the S-CFR of critically ill COVID-19 patients in the omicron period was higher than that in the delta period, especially in those aged ≤ 50 years. All of the patients who died had an underlying disease or obesity. In the same population, the vaccination rate was very low compared to that in the delta wave, indicating that non-vaccination significantly affected the progression to critical illness. Notably, there was a lack of prescription for Paxlovid for these patients although they satisfied the prescription criteria. Early diagnosis and active initial treatment was necessary, along with the proven methods of vaccination and personal hygiene. Further studies are needed to determine how each variant affects critically ill patients.

Deficits in Verbal Working Memory among College Students with Attention-Deficit/Hyperactivity Disorder Traits: An Event-related Potential Study

Seulki Kim,Myung-Sun Kim 대한정신약물학회 2016 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.14 No.1

Objective: This study investigated verbal working memory in college students with traits of attention-deficit/hyperactivity disorder (ADHD) using event-related potentials and the 2-back task. Methods: Based on scores on the Adult ADHD Self-Report Scale and Conners’ Adult ADHD Rating Scale, participants were assigned to the normal control (n=28) or ADHD-trait (n=29) group. The 2-back task, which was administered to evaluate working memory, consists of a congruent condition, under which the current stimulus is the same as the one presented two trials earlier, and an incongruent condition, under which the current stimulus is not the same as the one presented two trials earlier. The numbers 1, 2, 3, and 4 were used as stimuli. Results: On the 2-back task, the ADHD-trait group committed significantly more errors in response to congruent stimuli and showed a smaller P300 amplitude than did the control group. Conclusion: These results indicate that college students with ADHD traits have deficits in verbal working memory, possibly due to difficulties in memory updating or attentional allocation.

Growth patterns over 2 years after birth according to birth weight and length percentiles in children born preterm

Kim Seulki,Choi Yujung,Lee Seonhwa,Ahn Moon Bae,Kim Shin Hee,Cho Won Kyung,Cho Kyung Soon,Jung Min Ho,Suh Byung Kyu 대한소아내분비학회 2020 Annals of Pediatirc Endocrinology & Metabolism Vol.25 No.3

Purpose: To analyze growth patterns over 2 years after birth according to preterm infant birth weight and length percentiles. Methods: Anthropometric measurements of 82 preterm infants were retrospectively reviewed. Preterm infants with birth weight or length below the 10th percentile were classified as small for gestational age (SGA) (n=19) and those between the 10th and 89th percentile as appropriate for gestational age (AGA) (n=63). The association between the length standard deviation score (SDS) at 2 years of corrected age and clinical factors were analyzed. Results: The length SDS of the SGA group was significantly increased at 6 months (-1.30±1.71) and 24 months (-0.97±1.06) of corrected age. The length SDS was lower in the SGA group than those in the AGA group at 6 months (-1.30±1.71 vs. -0.25±1.15, P=0.004), 18 months (-0.97±1.39 vs. -0.03±1.29, P=0.015), and 24 months (-0.97±1.06 vs. -0.29±1.12, P=0.022,). The percentage of children with a length SDS of <-2 (growth failure) at 24 months was 15.8% in the SGA group and 4.8% in the AGA group (P=0.108). Multiple linear regression analysis demonstrated that length at 24 months of corrected age was negatively correlated with birth length below the 10th percentile (coefficient β=-0.91, P=0.001) and duration of stay in the neonatal intensive care unit (NICU) (coefficient β=-0.01, P=0.001). Conclusion: Despite the fact that catch-up growth occurs during the early period of infancy in a large portion of preterm SGA infants, a significant portion of these infants show growth failure at 24 months of age. Growth over 2 years after birth is affected by birth length and duration of stay in the NICU in preterm children.