Publications by authors named "HyeokJin Lee"

: Pertussis continues to pose a substantial global health challenge despite widespread vaccination programs. This study aimed to analyze the epidemiological characteristics of recent pertussis cases in the Gyeongnam region of South Korea. : We analyzed 419 pertussis cases in the Gyeongnam region of South Korea between October 2023 and April 2024, using data collected from epidemiological investigation reports, medical records, and interviews with health officials and school staff.

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As COVID-19 has become endemic, SARS-CoV-2 variants are becoming increasingly diverse, underscoring the escalating importance of global genomic surveillance. This study analyzed 86,762 COVID-19 samples identified in the Republic of Korea from September 2022 to November 2023. The results revealed a consistent increase in the prevalence of the XBB variants following the dominance of BN.

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The prevalence of highly pathogenic avian influenza (HPAI) A(H5N1) viruses has increased in wild birds and poultry worldwide, and concomitant outbreaks in mammals have occurred. During 2023, outbreaks of HPAI H5N1 virus infections were reported in cats in South Korea. The H5N1 clade 2.

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The objective of this study was to evaluate fish habitat suitability by simulating hydrodynamic and water quality factors using SWAT and HEC-RAS linked simulation considering time-series analysis. A 2.9 km reach of the Bokha stream was selected for the habitat evaluation of Zacco platypus, with hydrodynamic and water quality simulations performed using the SWAT and HEC-RAS linked approach.

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Although WHO declared the end of the public health emergency for coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), XBB lineages continue to evolve and emerge globally. In particular, XBB.1.

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Article Synopsis
  • The Korea Disease Control and Prevention Agency (KDCA) is conducting genomic surveillance to track and analyze SARS-CoV-2 variants in South Korea using over 102,000 patient samples.
  • COVID-19 variant waves emerged first internationally and then spread domestically, with key variants including B.41 in 2020, Delta in 2021, and various Omicron sub-lineages in 2022.
  • The KDCA has been proactive in detecting new variants before widespread outbreaks, highlighting the need for ongoing monitoring to safeguard public health against emerging threats.
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Background: Coronavirus disease 2019 (COVID-19) has been declared a global pandemic owing to the rapid spread of the causative agent, severe acute respiratory syndrome coronavirus 2. Its Delta and Omicron variants are more transmissible and pathogenic than other variants. Some debates have emerged on the mechanism of variants of concern.

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The Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began spreading rapidly in the community in November 2021, becoming the dominant variant in the Republic of Korea in 2022. Although its pathogenesis in healthy individuals was low, the severity and hospitalization rate was higher in the elderly and immunocompromised patients. We aimed to investigate the immunogenicity in acute and convalescent phases of breakthrough infection by Omicron in elderly individuals.

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The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic since 2019. Variants of concern (VOCs) declared by the World Health Organization require continuous monitoring because of their possible changes in transmissibility, virulence, and antigenicity. The Omicron variant, a VOC, has become the dominant variant worldwide since November 2021.

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Article Synopsis
  • The study focused on how long the Omicron variant of SARS-CoV-2 remains infectious by testing daily respiratory samples from isolated patients.
  • Findings showed that the Omicron variant had a higher virus culture positivity rate compared to the Delta variant within 8 days of symptom onset.
  • This suggests that the Omicron variant may be more readily transmissible shortly after symptoms appear.
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Neuroinflammation involves activation of glial cells in the brain, and activated microglia play a particularly important role in neurodegenerative diseases such as Alzheimer's disease (AD). In this study, we developed 5-cyano--(4-(4-(2-[F]fluoroethyl)piperazin-1-yl)-2-(piperidin-1-yl)phenyl)furan-2-carboxamide ([F]) for PET imaging of colony-stimulating factor 1 receptor (CSF1R), an emerging target for neuroinflammation imaging. Non-radioactive ligand exhibited binding affinity comparable to that of a known CSF1R inhibitor, 5-cyano--(4-(4-methylpiperazin-1-yl)-2-(piperidin-1-yl)phenyl)furan-2-carboxamide (CPPC).

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We report the rapid emergence of severe acute respiratory syndrome coronavirus 2 lineages B.1.619 and B.

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Article Synopsis
  • As COVID-19 continues, reinfections are likely to rise, but confirmation is challenging due to the need for whole-genome sequencing to assess genetic differences between infections.* -
  • In a study of four suspected reinfection cases in young patients (ages 10-29), researchers found that only two were confirmed reinfections, both involving the Epsilon variant.* -
  • The study highlights the increasing potential for reinfections amid the ongoing pandemic and emphasizes the importance of continuous monitoring of COVID-19 cases.*
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  • The study focused on individuals who re-tested positive for SARS-CoV-2 after recovering from their initial infection to assess the virus's infectivity.
  • Researchers analyzed 295 people with re-positive PCR results and their 836 close contacts, finding no viral presence in cell cultures from those with re-positive tests.
  • Out of the close contacts, three new cases of infection were identified, but all had prior infections, indicating that there was no evidence of targeted transmission from those with re-positive test results.
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  • - The study looked into how severe fever with thrombocytopenia syndrome virus (SFTSV) could spread in healthcare settings through aerosol transmission while using droplet precautions.
  • - It was found that SFTSV can spread from person to person during procedures that generate aerosols.
  • - As a result, researchers recommend adding airborne precautions to standard safety measures to reduce the risk of transmission through aerosols and droplets.
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Background: Hepatitis E virus (HEV) is an emerging pathogen associated with endemic and acute viral hepatitis. In this study, we investigate the HEV seroprevalence and putative risk factors by a nationwide cross-sectional study in the Republic of Korea.

Methods: The prevalence of anti-HEV antibody was investigated in 2,450 serum samples collected in fourth Korea National Health and Nutrition Examination Survey.

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Hepatitis A is a major infectious disease epidemiologically associated with foodborne and waterborne outbreaks. Molecular detection using real-time RT-PCR to detect the hepatitis A virus (HAV) in contaminated vegetables can be hindered by low-virus recoveries during the concentration process and by natural PCR inhibitors in vegetables. This study evaluated three virus concentration methods from vegetables: polyethylene glycol (PEG) precipitation, ultrafiltration (UF), and immunomagnetic separation (IMS).

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We propose an ultrafast nematic liquid crystal (LC) device without alignment layers, where both the dark and bright states can be realized by applying an electric field. A vertical electric field is applied to vertically align the LCs for the dark state, whereas an in-plane electric field is applied to homogeneously align the LCs for the bright state. We achieved a total response time of less than 3 ms in the proposed device.

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Objectives: The epidemiological patterns of endemic hepatitis A virus (HAV) are unclear in northeastern Asia depending on the ethnicity of the country in question. The purpose of this study was to investigate the seroprevalence of HAV in northeastern China, South Korea, and Japan.

Methods: A total of 1,500 serum samples were collected from five groups of inhabitants (300 each) who were over 40 years of age (Korean Chinese, indigenous Chinese, South Korean, Korean living in Japan, and indigenous Japanese).

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Hepatitis A virus is one of the most prominent causes of fecally transmitted acute hepatitis worldwide. In order to characterize the viral agents causing an outbreak in Korea (comprising North and South Korea) from June 2007 to May 2009, we collected specimens and performed genotyping of the VP1/P2A and VP3/VP1 regions of hepatitis A virus. We then used a multiple-alignment algorithm to compare the nucleotide sequences of the 2 regions with those of reference strains.

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Objectives: The purpose of this study was to investigate the seroprevalence of hepatitis A virus (HAV) and hepatitis E virus (HEV) in Korea during 2005.

Methods: Study subjects were selected from across Korea using a stratified multistage probability sampling design, and HAV and HEV seroprevalence was compared on the basis of sex, age, and residency. A total of 497 rural and urban people aged 10-99 years of age (mean ± SD age = 28.

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Background: Hepatitis A virus (HAV) is a causative agent of acute hepatitis, which is transmitted by person-to-person contact and via the faecal-oral route. Acute HAV infection is usually confirmed by anti-HAV IgM detection. In order to detect anti-HAV IgM in the serum of patients infected with HAV, we developed a rapid assay based on immunochromatography (ICA) and evaluated the sensitivity of this assay by comparing it with a commercial microparticle enzyme immunoassay (MEIA) that is widely used for serological diagnosis.

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Article Synopsis
  • In a study conducted in Korea during 2005-2006, researchers analyzed HAV strains from 160 IgM positive sera and found that 30% tested positive for HAV RNA, with significant detection from stool samples collected during an outbreak in Gyeonggi province.
  • Phylogenetic analysis of 54 HAV isolates identified the majority as genotype IA, with significant mutations such as the 810Q → S amino acid change, indicating the introduction of diverse strains, including genotype IIIA, possibly from areas with high HAV prevalence.
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For the synthesis of colloidal ternary ZnCdSe nanorods, CdSe nanorods were first prepared under a mixture of tetradecylphosphonic acid/trioctylphosphine oxide surfactants at 250 degrees C, and then ZnSe shell layer was grown onto CdSe nanorods at 180 degrees C, forming CdSeZnSe core/shell nanorods. Green-yellow emitting ternary ZnCdSe nanorods were obtained by a subsequent alloying process at 270 degrees C for 1-3 h through the diffusion of Zn ions into CdSe nanorods. The photoluminescence quantum yield (QY) of ZnCdSe nanorods was 5%-10%, which is higher than that from pristine CdSe nanorods (0.

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