Publications by authors named "Young Kyun Choi"
ZnMgO nanoparticles (ZMO NPs) are widely used as electron transport layers in optoelectronic devices such as light-emitting diodes (LEDs) and photodiodes (PDs) primarily because of their facile synthesis and excellent electron transport properties. However, the surface hydroxyl groups (‒OH) on the ZMO NPs introduce charge traps, inhibit electron transport, and reduce device stability, particularly under ambient humidity and oxygen. Therefore, in this study, an alcohol treatment (AT) method was developed to remove surface ‒OH via proton transfer to effectively reduce trap states and dipole moments and enhance surface passivation.
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- Current mortality risk models may not meet the specific needs of sepsis patients, prompting the development of a new predictive model aimed at accurately forecasting 28-day mortality in various care settings.
- This study utilized a large dataset of 7,436 sepsis patients from 20 hospitals for model development and validated it with 2,284 patients from 15 hospitals, showing solid performance in predicting mortality.
- The newly created point system model is accessible online, user-friendly, and successfully predicts outcomes for both community-acquired and hospital-acquired sepsis patients.
In this study, we present ultrasensitive infrared photodiodes based on PbS colloidal quantum dots (CQDs) using a double photomultiplication strategy that utilizes the accumulation of both electron and hole carriers. While electron accumulation was induced by ZnO trap states that were created by treatment in a humid atmosphere, hole accumulation was achieved using a long-chain ligand that increased the barrier to hole collection. Interestingly, we obtained the highest responsivity in photo-multiplicative devices with the long ligands, which contradicts the conventional belief that shorter ligands are more effective for optoelectronic devices.
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- The rising demand for self-powered photodetectors (PDs) for near-infrared (NIR) applications, like LIDAR and object recognition, is addressed through advancements in lead sulfide quantum dot-based photodetectors (PbS QPDs).
- A key challenge for PbS QPDs is their self-powered operation, which is negatively affected by carrier traps from surface defects and poor band alignment in the zinc oxide nanoparticle (ZnO NP) electron-transport layer (ETL).
- This study presents a novel treatment using azide ions on the ZnO NP ETL, resulting in improved carrier lifetime, mobility, and overall performance metrics, showing significant enhancements in responsivity and detectivity
Quantum dot photodiodes (QPDs) have garnered significant attention because of their unparalleled near-infrared (NIR) detection capabilities, primarily attributable to their size-dependent bandgap tunability. Nevertheless, the broadband absorption spectrum of QPD engenders substantial noise floor within superfluous visible light regions, notably hindering their use in several emerging applications necessitating the detection of faint micro-light signals. To overcome these hurdles, a self-screenable NIR QPD featuring an internal optical filter with a thick polymeric interlayer to reduce electronic noise is demonstrated.
View Article and Find Full Text PDFHighly Conductive and Sensitive Wearable Strain Sensors with Metal/Nanoparticle Double Layer for Noninterference Voice Detection.
ACS Appl Mater Interfaces
September 2023
Article Synopsis
- A new skin-attachable wearable sensor has been developed for voice recognition, which can capture physiological data effectively without background noise interference.
- This sensor uses a unique double-layer structure made of silver nanoparticles and metal on a biocompatible material, allowing it to be highly sensitive and fast in detecting sound waves.
- It can differentiate between different types of voice qualities and shows promise for applications in personalized healthcare and other computing technologies.
In this study, a temperature-insensitive strain sensor that detects only the strain without responding to the temperature was designed. The transport mechanism and associated temperature coefficient of resistance (TCR) of a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin film were modified through secondary doping with dimethyl sulfoxide (DMSO). Upon DMSO-doping, the carrier transport mechanism of the PEDOT:PSS thin film transitioned from hopping to band-like transport, with a morphological change.
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- Early nutritional support is crucial for critically ill patients, especially those neurological issues, and this study examined its impact on clinical outcomes in neurosurgical ICU patients from 2013 to 2019.
- A total of 1,353 patients were included, with 384 receiving early nutrition within the first 72 hours, though results showed no significant differences in mortality or infection rates when comparing early to late nutrition after adjusting for biases.
- Notably, patients receiving early enteral nutrition had lower mortality and infection rates compared to those on early parenteral nutrition or late nutrition, indicating that early enteral nutrition may be particularly beneficial for these patients.
Article Synopsis
- - A new resistive-type strain sensor has been developed that minimizes temperature interference, ensuring it only detects strain and not temperature variations.
- - The sensor's effectiveness comes from using metal nanoparticles with carefully modulated temperature coefficients of resistance (TCR) through a hybrid chemical process, achieving a very low TCR of 1.9 × 10 K.
- - This high-performance sensor can accurately track various strain applications, from large body movements like those in the wrist and knee to delicate actions such as pulse detection and calligraphy, without being affected by temperature changes.
Article Synopsis
- This study analyzed the outcomes of COVID-19 patients receiving at-home care in Yeongdeungpo-gu, Seoul, from October to December 2021.
- A total of 1,422 patients were monitored, with most being older adults and without underlying health conditions; the median care length was 8 days.
- It was found that patients with diabetes and those who were presymptomatic were more likely to be transferred to healthcare facilities, but overall, there were no significant safety issues with at-home care.
Postvaccination Multisystem Inflammatory Syndrome in Adult with No Evidence of Prior SARS-CoV-2 Infection.
Emerg Infect Dis
February 2022
Article Synopsis
- A 22-year-old woman in South Korea developed several health issues, including myocarditis and pericarditis, ten days after her first COVID-19 vaccine dose.
- She also experienced gastrointestinal symptoms and a rash, indicating a systemic response.
- Medical assessment concluded that her conditions were part of multisystem inflammatory syndrome linked to the COVID-19 vaccination, with no prior infection with the virus.
Antibiotic Resistance Patterns of Isolated from Patients with Healthcare-Associated Infections.
Infect Chemother
June 2021
Background: There have been recent proposals to categorize healthcare-associated infections (HCAIs) separately from community-acquired infections (CAIs). The aim of this study was to compare the antibiotic resistance of pathogens causing CAIs, HCAIs, and hospital-acquired infections (HAIs) in Korea, and to investigate the need for different empirical antibiotics therapy for CAIs and HCAIs.
Materials And Methods: This prospective study was conducted in a university hospital between March and December 2019.
Positivity of Carbapenemase-producing in Patients Following Exposure within Long-term Care Facilities in Seoul, Korea.
J Korean Med Sci
September 2020
Background: Carbapenemase-producing (CPE) are emerging as a worldwide threat. Long-term care facilities (LTCFs) are considered a reservoir for CPE and play a central role in transmission to acute care hospitals. We investigated the CPE positivity in patients exposed to CPE in LTCFs.
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- Carbapenem-resistant gram-negative pathogen (CR-GNP) infections in burn patients are increasing, posing a challenge due to limited treatment options and rising resistance to colistin, the main treatment.
- A study conducted at Hangang Sacred Heart Hospital compared outcomes of colistin monotherapy and colistin-based combination therapy in burn patients with CR-GNP bacteremia from 2014 to 2017, analyzing 84 patients in total.
- The results showed no significant differences in eradication rates (71.9% vs. 75.0%) or 30-day mortality rates (31.2% vs. 38.5%) between the two treatment groups, indicating that colistin combination therapy did not provide additional benefits over monotherapy
Article Synopsis
- * Acinetobacter baumannii was found to be the most common pathogen, with trends indicating an increase in Klebsiella spp. and a decrease in Pseudomonas aeruginosa over the six-year period, particularly as hospital stays lengthened.
- * The research highlights a significant rise in Carbapenem-resistant Enterobacteriaceae (CRE) infections during extended hospitalizations, suggesting the need for early antibiotic treatment targeting multidrug-resistant bacteria in burn patients to prevent severe complications.
A case of a patient with Takayasu arteritis treated with left subclavian artery stent implantation.
J Cardiol Cases
October 2015
Article Synopsis
- - Takayasu arteritis is a rare chronic inflammatory disease that mainly affects large blood vessels like the aorta, mostly seen in young people, particularly females in Asia and Latin America.
- - The report highlights a case of a young Asian female patient who experienced multiple artery involvement and was treated using percutaneous transluminal angioplasty, a minimally invasive procedure.
- - The study provides valuable insights into this rare condition by presenting clear images of the arteries affected and includes an 8-month follow-up on the effectiveness of the angioplasty treatment.
A phase II study of capecitabine and oral leucovorin as a third-line chemotherapy in patients with metastatic colorectal cancer.
Cancer Chemother Pharmacol
March 2015
Article Synopsis
- The study aimed to assess the effectiveness and safety of combining capecitabine and oral leucovorin (LV) as a third-line treatment for patients with metastatic colorectal cancer (CRC) who were resistant to previous chemotherapy regimens.
- A total of 25 patients participated, and results showed that 12% achieved a partial response (PR), while 56% experienced disease control, with median progression-free survival of 2.8 months and overall survival of 7.1 months.
- The treatment was generally well-tolerated, with common side effects being hand-foot syndrome and mucositis, suggesting that this combination could be a viable option for patients who have limited treatment choices.
Bispectral index monitoring to assess the level of consciousness in patients with brain injury.
Korean J Anesthesiol
August 2009
Background: It is important to assess the level of consciousness in patients with brain injuries to determine modes of treatment and prognosis. We evaluated the Bispectral Index (BIS) to determine if it could be used as an objective tool for evaluation of the level of consciousness in brain-injured patients. We also compared the BIS values to clinical sedation scales such as the Glasgow Coma Scale (GCS), Richmond Agitation-Sedation Scale (RASS), and the Reaction Level Scale (RLS).
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