SARS-CoV-2 mRNA Vaccine Elicits Sustained T Cell Responses Against the Omicron Variant in Adolescents

Sujin Choi,Sang-Hoon Kim,Mi Seon Han,Yoonsun Yoon,Yun-Kyung Kim,Hye-Kyung Cho,Ki Wook Yun,Seung Ha Song,Bin Ahn,Ye Kyung Kim,Sung Hwan Choi,Young June Choe,Heeji Lim,Eun Bee Choi,Kwangwook Kim,Seokhwa 대한면역학회 2023 Immune Network Vol.23 No.4

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been acknowledged as an effective mean of preventing infection and hospitalization. However, the emergence of highly transmissible SARS-CoV-2 variants of concern (VOCs) has led to substantial increase in infections among children and adolescents. Vaccineinduced immunity and longevity have not been well defined in this population. Therefore, we aimed to analyze humoral and cellular immune responses against ancestral and SARSCoV- 2 variants after two shots of the BNT162b2 vaccine in healthy adolescents. Although vaccination induced a robust increase of spike-specific binding Abs and neutralizing Abs against the ancestral and SARS-CoV-2 variants, the neutralizing activity against the Omicron variant was significantly low. On the contrary, vaccine-induced memory CD4+ T cells exhibited substantial responses against both ancestral and Omicron spike proteins. Notably, CD4+ T cell responses against both ancestral and Omicron strains were preserved at 3 months after two shots of the BNT162b2 vaccine without waning. Polyfunctionality of vaccine-induced memory T cells was also preserved in response to Omicron spike protein. The present findings characterize the protective immunity of vaccination for adolescents in the era of continuous emergence of variants/subvariants.

Liquid crystalline and ion-conducting properties of mesogenic dendron–coil-dendron copolymers: characterization of LC phases using normalized conductivity

Choi, Sujin,Cho, Byoung-Ki The Royal Society of Chemistry 2013 Soft matter Vol.9 No.16

<P>We synthesized three dendron–coil-dendron block copolymers consisting of ionophilic poly(ethylene oxide) (PEO) coils and mesogenic dendrons with four octadecyl peripheries <I>via</I> stepwise click reactions. The obtained polymers were doped with lithium triflate, whose concentration per ethylene oxide unit was 0.05. As characterized by optical polarized microscopy (POM) and X-ray scattering techniques, polymer <B>1</B> with the shortest PEO coil (<I>M</I><SUB>n</SUB> = 2000 g mol<SUP>−1</SUP>) did not show the liquid crystalline (LC) phase, while its ionic sample (<B>1-Li<SUP>+</SUP></B>) exhibited a hexagonal columnar LC phase. On the other hand, <B>2</B> and <B>3</B> (with PEOs of <I>M</I><SUB>n</SUB> = 4000 and 8000 g mol<SUP>−1</SUP>, respectively) displayed identical LC morphologies to <B>2-Li<SUP>+</SUP></B> and <B>3-Li<SUP>+</SUP></B>, respectively, although the phase transition temperatures increased upon salt doping. For <B>2</B> and <B>2-Li<SUP>+</SUP></B>, gyroid and lamellar LC phases were observed with increasing temperature, while <B>3</B> and <B>3-Li<SUP>+</SUP></B> showed only a lamellar LC phase. The observed ion-transporting behavior was strongly dependent upon the connectivity of ion-conducting domain structures. The investigation of the morphology–conductivity correlation using a normalized conductivity (<I>σ</I>* = <I>σ</I>/<I>f</I>, where <I>σ</I> and <I>f</I> are the original conductivity and the PEO volume fraction) indicated that the 3-D gyroid LC phase showed the highest value, while the lowest conductivity was found in the 1-D columnar structure at identical temperatures. Additionally, the gyroid to lamellar phase transition temperature of <B>2-Li<SUP>+</SUP></B> could be determined by the <I>σ</I>*, which was consistent with the X-ray data. Consequently, the results can be explained by the fact that the ionic pathway becomes complicated when going from higher to lower dimensional structures in polygrain samples.</P> <P>Graphic Abstract</P><P>Ion-conducting properties of dendron–coil-dendron block copolymers are dependent upon the domain dimensionality of the liquid crystalline morphologies, which can be properly analyzed using a normalized conductivity (<I>σ</I>*) instead of original conductivity (<I>σ</I>). <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3sm27959f'> </P>

Characterization of Deposited PZT Thin Film by RF Magnetron Co-sputtering on Si(100) at various O₂ gas ratio

Sujin Choi,Juyun Park,Eunkang Jeong,Yong-Cheol Kang 한국진공학회 2014 한국진공학회 학술발표회초록집 Vol.2014 No.8

Transmission-type photonic crystal structures for color filters

Choi, Hee-Jin,Choi, Sujin,Yoo, Young-Eun,Jeon, Eun-chae,Yi, Yun,Park, Shinwoong,Choi, Doo-Sun,Kim, Hwi The Optical Society 2013 Optics express Vol.21 No.15

Analysis of Cell Variability Impact on a 3-D Vertical RRAM (VRRAM) Crossbar Array Using a Modified Lumping Method

Choi, Sujin,Sun, Wookyung,Shin, Hyungsoon IEEE 2019 IEEE transactions on electron devices Vol.66 No.1

<P>In this paper, the read margin (RM) and write power (WP) of 3-D vertical resistive random access memory (VRRAM) are analyzed by considering the variation in RRAM cell (self-rectifying cell) characteristics. To demonstrate the cell variation effect on a large 3-D VRRAM array, we develop a modified lumping method in HSPICE simulator and show that this method substantially reduces the computation time while maintaining high accuracy. Read and write performances including cell variation are investigated according to various array sizes and RRAM characteristics. A large distribution of cell current reduces the RM but hardly affects the WP. Moreover, in 3-D VRRAM with a small number of wordline (WL) layers, a large on/off ratio (R<SUB>HRS</SUB>/R<SUB>LRS</SUB>) is advantageous for improving the RM and reducing the variation effect. In contrast, a large on/off ratio has little effect on the RM in 3-D VRRAM with many WL layers. This difference occurs because the increased leakage induced in the half-selected cells mainly affects the RM, and the half-selected cells are located in the selected vertical pillar in 3-D VRRAM.</P>

Factors Associated with Reaching Mid-Parental Height in Patients Diagnosed with Inflammatory Bowel Disease in Childhood and Adolescent Period

Choi So Yoon,Choi Sujin,Choe Byung-Ho,Park Jae Hong,Choi Kwang-Hae,Lee Hae Jeong,Park Ji Sook,Seo Ji Hyun,Kim Jae Young,Jang Hyo-Jeong,Hong Suk Jin,Kim Eun Young,Lee Yeoun Joo,Kang Ben 거트앤리버 소화기연관학회협의회 2024 Gut and Liver Vol.18 No.1

Background/Aims: The recent update on the Selecting Therapeutic Targets in Inflammatory Bowel Disease initiative has added normal growth in children as an intermediate target in Crohn’s disease and ulcerative colitis. We aimed to investigate factors associated with reaching mid-parental height (MPH) in patients diagnosed with inflammatory bowel disease in childhood and the adolescent period. Methods: This multicenter retrospective observational study included pediatric patients with inflammatory bowel disease that had reached adult height. Factors associated with reaching MPH were investigated by logistic regression analyses. Results: A total of 166 patients were included in this study (128 Crohn’s disease and 38 ulcerative colitis). Among them, 54.2% (90/166) had reached their MPH. Multivariable logistic regression analysis revealed that height Z-score at diagnosis and MPH Z-score were independently associated with reaching MPH (odds ratio [OR], 8.45; 95% confidence interval [CI], 4.44 to 17.90; p<0.001 and OR, 0.11; 95% CI, 0.04 to 0.24; p<0.001, respectively). According to the receiver operating characteristic curve analysis, the optimal cutoff level of "height Z-score at diagnosis minus MPH Z-score" that was associated with reaching MPH was –0.01 with an area under the curve of 0.889 (95% CI [0.835 to 0.944], sensitivity 88.9%, specificity 84.2%, positive predictive value 87.0%, negative predictive value 86.5%, p<0.001). Conclusions: Height Z-score at diagnosis and MPH Z-score were the only factors associated with reaching MPH. Efforts should be made to restore growth in pediatric patients who present with a negative “height Z-score at diagnosis minus MPH Z-score.”

An exploratory approach to a Twitter-based community centered on a political goal in South Korea: Who organized it, what they shared, and how they acted

Choi, Sujin,Park, Han Woo SAGE Publications 2014 NEW MEDIA & SOCIETY - Vol.16 No.1

<P>This study provides an empirical account of how an online community has employed social media to mobilize people for a political goal. The case explored is a Twitter-based community in South Korea that calls for the elimination of a conservative national daily newspaper and whose activism is contextualized in the political history of Korea. Based on the mixed-method approach, the research results suggest that the role of the group organizer as an information provider and coordinator contributed to the sustainability of the group, and that group members formed a collective identity through the framing process of discourse. In addition, massive “retweeting” and “culture jamming” tactics were found to be strategically employed to enhance group solidarity, to broaden the base of support, and to crystallize involvement into political acts with other offline actions. Rather than decaying to an echo chamber or “slacktivism”, the online community seemed to demonstrate a new form of collective activism through the mediation of technology in everyday life.</P>

Quantitative modal analysis of optical power flow and energy loss in photonic structures with a dipole emission source.

Choi, Sujin,Baek, Seungin,Im, Dajeong,Kahng, Hyun Kook,Kim, Hwi Optical Society of America 2014 Optics express Vol.22 No.15

<P>Fourier modal method based quantitative analysis method of optical power flow and energy loss in general multi-block photonic structures with an internal dipole emitter is described. The analytic expressions of modal power flow and loss are derived for accurate and efficient quantitative analysis. It is revealed that a few dominating excited photonic modes substantially govern the internal energy flow and energy loss. The optical characteristics of the dominant modes are investigated.</P>

Outcomes of pediatric acute myeloid leukemia patients with FLT3-ITD mutations in the pre-FLT3 inhibitor era

Choi Sujin,Kim Bo Kyung,Ahn Hong Yul,Hong Kyung Taek,Choi Jung Yoon,Shin Hee Young,Kang Hyoung Jin 대한혈액학회 2020 Blood Research Vol.55 No.4

Background Acute myeloid leukemia (AML) with internal tandem duplication in FMS-like tyrosine kinase 3 (FLT3-ITD) is associated with poor outcomes. This study aimed to analyze the outcomes of pediatric AML patients with FLT3-ITD mutations in the pre-FLT3 inhibitor era. Methods We retrospectively reviewed and identified 18 patients diagnosed with non-M3 AML with FLT3-ITD mutations at Seoul National University Children’s Hospital between May 2008 and August 2019. Results The median age was 13 years (range, 6‒19 yr). The median follow-up time was 43 months (range, 6‒157 mo). Fourteen patients received BH-AC-based (N4-Behenoy1-1--D-arabinofuranosy1cytosine) and 4 received cytarabine-based induction chemotherapy. Complete remission (CR) was achieved in 72.2% of the patients after the first induction chemotherapy and 80% of the patients achieved CR after salvage therapy. The overall CR rate was 94% (17/18 patients). These 17 patients underwent hematopoietic stem cell transplantation (9 matched unrelated donors, 5 matched related donors, and 3 haploidentical donors). Relapse occurred in 22% of the patients. Event free survival and overall survival rates were 53.8±12.1% and 53.6±12.1%, respectively, and they were not significantly different according to the type of induction chemotherapy (P =0.690) or the type of donor (P =0.102). Conclusion This study outlines the outcomes of pediatric AML patients with FLT3-ITD-mutations in one institution over a decade. Outcomes were significantly improved in this study compared to our previous report in 2004, where RFS and EFS were 0%. This study can provide baseline data for pediatric patients in the pre-FLT3 inhibitor era.

Vedolizumab Is Safe and Efficacious for the Treatment of Pediatric-Onset Inflammatory Bowel Disease Patients Who Fail a Primary Biologic Agent

Choi Sujin,Kim Eun Sil,Kwon Yiyoung,Kim Mi Jin,Choe Yon Ho,Choe Byung-Ho,Kang Ben 대한의학회 2022 Journal of Korean medical science Vol.37 No.37

Background: Vedolizumab (VDZ) is currently licensed for use in adults for the treatment of inflammatory bowel disease (IBD). We aimed to investigate the clinical course of pediatric-onset IBD following treatment with VDZ as more than a secondary biologic agent. We also evaluated factors associated with secondary loss of response (LOR) and durability of VDZ treatment. Methods: Pediatric-onset IBD patients diagnosed at an age younger than 18 years who had received VDZ as more than a secondary biologic agent were included in this retrospective observational study conducted at the Department of Pediatrics of two centers in Korea. Comparative analysis was conducted between groups divided according to the development of secondary LOR during VDZ treatment. Results: A total of 24 patients comprising 10 patients with Crohn’s disease and 14 with ulcerative colitis were included. Of these, 19 were male and 5 were female. The mean age at diagnosis was 14.6 ± 2.5 years. The mean age at initiation of VDZ was 20.5 ± 2.8 years. Nine patients (37.5%) had received two or more biologic agents before starting VDZ. During a median of 0.9 years follow-up from VDZ initiation, 9 patients (37.5%) experienced LOR requiring interval shortening and 4 patients (16.7%) were changed to a different biologic agent. According to multivariate Cox proportional hazard regression analysis, administration of two or more biologic agents before VDZ treatment was the only factor positively associated with LOR (hazard ratio [HR], 5.6; 95% confidence interval [CI], 1.026–30.56; P = 0.047), while LOR was the only factor negatively associated with VDZ durability (HR, 0.003; 95% CI, 0.00–0.08; P = 0.010). No adverse events were observed during treatment with VDZ. Conclusion: VDZ is safe and efficacious for the treatment of pediatric-onset IBD patients failing a primary biologic agent. The durability of VDZ may be enhanced by introducing VDZ earlier in the disease course. Further prospective studies in children are required in the future to validate these findings.