1.Thermal modulation and airflow distribution determine hair drying efficiency, moisture behavior in human hair in Republic of Korea: an ex vivo study
Tae-Rin KWON ; Doohyun HAN ; Hyoung Jun KIM ; Jungwook KIM ; Byung Ho YOON ; Sung Yong PARK ; Jun-Seok LEE ; Na Mi BYUN ; Jungkwan LEE ; Jungwon LEE ; Kwang Ho YOO
Medical Lasers 2026;15(1):69-76
Background:
Hair drying is a routine cosmetic practice; however, excessive heat exposure and non-uniform airflow can compromise cuticle integrity, degrade hair sensory properties, and induce scalp discomfort. This study aimed to (i) identify a practical thermal window that minimizes perturbation of hair fiber surface and quantify late-stage thermal amplification during the drying process using percentage-based analysis.
Methods:
Temperature-dependent hair fiber surface morphology was examined by scanning electron microscopy (SEM) after controlled exposure to 41°C, 60°C, 80°C, and 90°C using virgin and chemically damaged hair. The drying efficacy was assessed using the surface and internal moisture indices under airflow shaping (test) and uniform airflow (control) conditions. Hair fluttering (maximum angular displacement) was evaluated before and after drying under warm-cool alternating (60°C-80°C) versus constant hot airflow (80°C).
Results:
SEM revealed temperature-dependent cuticle disruption, with markedly greater surface perturbation at 90°C than at 80°C. Infrared thermography demonstrated pronounced late-stage thermal amplification: at 150 seconds, the surface temperature increased by 295% (from 24.2°C to 72.0°C) at 90°C, compared with 207% (from 24.2°C to 50.7°C) at 80°C. Airflow shaping promoted preferential surface moisture removal (–13.6%) while limiting internal dehydration (–9.4%), whereas the control condition exhibited minimal surface drying (–4.6%) but substantial internal moisture loss (–22.2%). Warm-cool modulation increased hair fluttering by +11.0%, whereas constant hot airflow reduced it (–3.7%).
Conclusion
These findings indicate that spatial and temporal control of heat delivery represents a clinically relevant design strategy beyond the nominal temperature specification in hair-drying devices.
2.Thermal cycling with focused airflow prevents α-keratin denaturation and structural damage in human hair in Korea:an ex vivo study
Tae-Rin KWON ; Doohyun HAN ; Jungwook KIM ; Hyoung Jun KIM ; Byung Ho YOON ; Dong Wook MOON ; Jungkwan LEE ; Kwang Ho YOO
Medical Lasers 2025;14(3):168-174
Background:
Excessive heat from household styling devices denatures α-keratin, damages the cuticle, and degrades overall hair quality. Conventional blow-dryer temperatures often exceed 90°C, surpassing the safety threshold for keratin fibers. To determine whether combining focused airflow with rapid thermal cycling (peak temperatures ≤60°C) attenuates multiscale hair damage compared with continuous-heat drying.
Methods:
Human-hair tresses were assigned either to a focused-flow dryer operating in alternating cool/warm cycles or to a continuous-heat mode. Jet characteristics were quantified using planar particle-image velocimetry, and airflow temperatures were recorded using micro-thermocouples. Post-treatment analyses included scanning electron microscopy (cuticular surface roughness, Ra), single-fiber tensile testing, crosssectional densitometry (fiber compactness), and confocal Raman spectroscopy (α-helix/disulfide bond integrity).
Results:
Thermal cycling with focused airflow increased the central-core flow fraction from 37% to 64% and confined hair-surface peaks to 58°C-60°C. Alternating hot-cold drying reduced cuticlar surface roughness by approximately 7.3%, whereas continuous hat air drying increased roughness by 4.9%. Ultimate tensile strength was essentially preserved (–0.4%) under cycling but fell by 9.4% with uninterrupted heat (p = 0.003).Compactness loss was limited to 33% vs. 50%, and the S-S disulfide bond (~510 cm –1 )/C-H bending vibration band (~720 cm –1 ) ratio decreased by only 11% (vs. 19% under continuous heat).
Conclusion
Brief cooling intervals, when paired with a confined airflow, effectively prevented α-keratindenaturation and structural collapse. These findings support a clinically relevant approach to preserving hairfiber integrity during routine hair care and styling.
3.Comprehensive Analysis of Individual Anatomical Structures for Micturition Symptoms and Maximum Flow Rate in Men With Benign Prostatic Hyperplasia/Lower Urinary Tract Symptoms
Dae Ho KIM ; Kwang Suk LEE ; Kyo Chul KOO ; Byung Ha CHUNG ; Jeong Woo YOO
International Neurourology Journal 2023;27(2):146-154
Purpose:
Individual anatomical structural variations, including intravesical prostatic protrusion (IPP), prostatic urethral angle (PUA), prostatic urethral length, or prostatic apex shape, were correlated with micturition symptoms. We aimed to investigate the effects of these variables on micturition symptoms in men with benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS).
Methods:
This observational study was based on data from 263 men with the first visit to health promotion center and without BPH/LUTS treatment between March 2020 and September 2022. A multivariate analysis was performed to determine the variables affecting total international prostate symptom score, maximum flow rate (Qmax), and voiding efficacy (postvoid residual volume to total bladder volume ratio).
Results:
Of 263 patients, decreasing PUA increases the severity of international prostate symptoms score (mild, 141.9°; moderate, 136.0°; severe, 131.2°; P<0.015). A multivariate analysis reported that the total international prostate symptom score was correlated with age (P=0.002), PUA (P=0.007), and Qmax (P=0.008). Qmax was negatively associated with IPP (P=0.002). In subanalysis for large prostate volume (≥30 mL, n=81), international prostate symptom score was correlated with PUA (P=0.013), Qmax was correlated with prostatic apex shape (P=0.017), and length of proximal prostatic urethra (P=0.007). IPP was not identified as a significant factor. For small prostate volume (<30 mL, n=182), age (P=0.011) and prostate volume (P=0.004) are correlated with increasing Qmax.
Conclusions
This study presented that individual anatomical structure variations influenced the micturition symptoms according to prostate volume. To identify the major resistant factors in men with BPH/LUTS, further studies are required to investigate which components played a role in major resistant factors for micturition symptoms.
4.Developing a Diagnostic Bundle for Bronchiectasis in South Korea: A Modified Delphi Consensus Study
Hayoung CHOI ; Hyun LEE ; Seung Won RA ; Jong Geol JANG ; Ji-Ho LEE ; Byung Woo JHUN ; Hye Yun PARK ; Ji Ye JUNG ; Seung Jun LEE ; Kyung-Wook JO ; Chin Kook RHEE ; Changwhan KIM ; Sei Won LEE ; Kyung Hoon MIN ; Yong-Soo KWON ; Deog Kyeom KIM ; Jin Hwa LEE ; Yong Bum PARK ; Eun Hee CHUNG ; Yae-Jean KIM ; Kwang Ha YOO ; Yeon-Mok OH
Tuberculosis and Respiratory Diseases 2022;85(1):56-66
Background:
Because the etiologies of bronchiectasis and related diseases vary significantly among different regions and ethnicities, this study aimed to develop a diagnostic bundle for bronchiectasis in South Korea.
Methods:
A modified Delphi method was used to develop expert consensus statements on a diagnostic bundle for bronchiectasis in South Korea. Initial statements proposed by a core panel, based on international bronchiectasis guidelines, were discussed in an online meeting and two email surveys by a panel of experts (≥70% agreement).
Results:
The study involved 21 expert participants, and 30 statements regarding a diagnostic bundle for bronchiectasis were classified as recommended, conditional, or not recommended. The consensus statements of the expert panel were as follows: A standardized diagnostic bundle is useful in clinical practice; diagnostic tests for specific diseases, including immunodeficiency and allergic bronchopulmonary aspergillosis, are necessary when clinically suspected; initial diagnostic tests, including sputum microbiology and spirometry, are essential in all patients with bronchiectasis, and patients suspected with rare causes such as primary ciliary dyskinesia should be referred to specialized centers.
Conclusion
Based on this Delphi survey, expert consensus statements were generated including specific diagnostic, laboratory, microbiological, and pulmonary function tests required to manage patients with bronchiectasis in South Korea.
5.A Multicenter Study to Identify the Respiratory Pathogens Associated with Exacerbation of Chronic Obstructive Pulmonary Disease in Korea
Hyun Woo LEE ; Yun Su SIM ; Ji Ye JUNG ; Hyewon SEO ; Jeong-Woong PARK ; Kyung Hoon MIN ; Jae Ha LEE ; Byung-Keun KIM ; Myung Goo LEE ; Yeon-Mok OH ; Seung Won RA ; Tae-Hyung KIM ; Yong il HWANG ; Chin Kook RHEE ; Hyonsoo JOO ; Eung Gu LEE ; Jin Hwa LEE ; Hye Yun PARK ; Woo Jin KIM ; Soo-Jung UM ; Joon Young CHOI ; Chang-Hoon LEE ; Tai Joon AN ; Yeonhee PARK ; Young-Soon YOON ; Joo Hun PARK ; Kwang Ha YOO ; Deog Kyeom KIM
Tuberculosis and Respiratory Diseases 2022;85(1):37-46
Background:
Although respiratory tract infection is one of the most important factors triggering acute exacerbation of chronic obstructive pulmonary disease (AE-COPD), limited data are available to suggest an epidemiologic pattern of microbiology in South Korea.
Methods:
A multicenter observational study was conducted between January 2015 and December 2018 across 28 hospitals in South Korea. Adult patients with moderate-to-severe acute exacerbations of COPD were eligible to participate in the present study. The participants underwent all conventional tests to identify etiology of microbial pathogenesis. The primary outcome was the percentage of different microbiological pathogens causing AE-COPD. A comparative microbiological analysis of the patients with overlapping asthma–COPD (ACO) and pure COPD was performed.
Results:
We included 1,186 patients with AE-COPD. Patients with pure COPD constituted 87.9% and those with ACO accounted for 12.1%. Nearly half of the patients used an inhaled corticosteroid-containing regimen and one-fifth used systemic corticosteroids. Respiratory pathogens were found in 55.3% of all such patients. Bacteria and viruses were detected in 33% and 33.2%, respectively. Bacterial and viral coinfections were found in 10.9%. The most frequently detected bacteria were Pseudomonas aeruginosa (9.8%), and the most frequently detected virus was influenza A (10.4%). Multiple bacterial infections were more likely to appear in ACO than in pure COPD (8.3% vs. 3.6%, p=0.016).
Conclusion
Distinct microbiological patterns were identified in patients with moderate-to-severe AE-COPD in South Korea. These findings may improve evidence-based management of patients with AE-COPD and represent the basis for further studies investigating infectious pathogens in patients with COPD.
6.Prostate-Specific Antigen Variation as a Predictor of Prostate Cancer in Patients With Prostate-Specific Antigen ≤20 ng/mL Who Underwent Magnetic Resonance Imaging-Targeted Prostate Biopsy
Tae Hyun HWANG ; Kwang Suk LEE ; Kyo Chul KOO ; Byung Ha CHUNG ; Jeong Woo YOO
Korean Journal of Urological Oncology 2022;20(2):123-132
Purpose:
We investigated the role of prostate-specific antigen (PSA) variation as a predictor of prostate cancer in patients who underwent prebiopsy multiparametric magnetic resonance imaging (MRI).
Materials and Methods:
The clinicopathological data of 266 patients with PSA ≤20 ng/mL who underwent prebiopsy MRI and prostate biopsy between September 2019 and February 2021 were included. PSA variation was defined as the difference in PSA values taken when a prostate biopsy was recommended and performed (median 20 days). Receiver operating characteristic (ROC) curves and area under the ROC curves (AUCs) for predicting prostate cancer were analyzed through 4 models that considered conventional clinical variables and PSA variation.
Results:
Of the 258 patients, 166 (64.3%) were diagnosed with prostate cancer. The prostate cancer (+) group had a lower median PSA variation (-0.09 mg/mL vs. -0.27 ng/mL, p=0.006) and higher proportion of patients with PSA variation within -0.54 to 0.05 ng/mL (40 ng/mL [range, 24.1%] vs. 9 ng/mL [9.8%], p=0.002) than the prostate cancer (-) group. There was no significant difference in the duration between the 2 PSA measurements. When PSA variation and conventional variables, such as age, PSA density, prostate biopsy history, number of target lesions, were considered, the highest AUC value was 0.870. In a subgroup analysis of patients with PSA ≤10 ng/mL, the highest AUC value was 0.860 when PSA variation and conventional variables were considered.
Conclusions
A large PSA variation within 1 month was a negative predictor of prostate cancer among patients who underwent prebiopsy MRI.
7.The work and socioeconomic burden of emergency physicians in the COVID-19 pandemic: 2020 Korean Emergency Physician Survey
In Hwan YEO ; Mi Jin LEE ; Tae Jin SIM ; Hyung Min LEE ; Kwang Hyun CHO ; In Byung KIM ; Yoo Sang YOON ; Kyung Hye PARK ; Song Yi PARK ; Hong Jae KIM ; Dong Hoon KEY ; Beom Sok SEO ; Young Min JOO ; Chang Gun JEE ; Suk Jae CHOI ; Ji Hun KANG ; Woo Jin JUNG ; Dae Sung LIM ; Eu Sun LEE
Journal of the Korean Society of Emergency Medicine 2022;33(4):67-75
Objective:
This study evaluated the anxiety, work, and socioeconomic burden of emergency physicians (EP) during the coronavirus disease 2019 (COVID-19) pandemic in South Korea.
Methods:
A cross-sectional observational study was conducted using data from the 2020 Korean Emergency Physician Survey that included the following domains: hospital resources of suspected COVID-19 patients, availability of personal protective equipment, levels of home and workplace anxiety, the severity of work burnout, identification of stressors, changes in personal environments, and measures to decrease stress/anxiety.
Results:
Totally, 855 eligible participants were enrolled in the study. A statistically significant deterioration was observed in response to decreased working income or an unstable employment situation (0.46±0.88 points). The median number of patients with confirmed COVID-19 was 2.72. The risk of infection during emergency department (ED) work was found to be significantly increased (P<0.01). Of the 751 respondents (91.4%) who reported patient contact during their survey phase, 516 (62.8%) reported having taken the COVID-19 reverse transcription polymerase chain reaction test. The major factors that affected worsening of the work burden were determined to be unsuitable inter-hospital transfer arrangements for febrile patients (3.46±1.06 before vs. 1.99±1.16 after the pandemic, P<0.01) and delayed consultation for patients with fever or respiratory symptoms in the ED (3.20±1.06 before vs. 2.66±1.10 after the pandemic, P<0.01).
Conclusion
During the peak phase, the COVID-19 pandemic induced substantial workplace and socioeconomic burdens for Korean EPs. The sustained impact of the pandemic on the wellness of EPs deserves further investigation to guide targeted interventions.
8.Analysis of factors influencing emergency physician’s choice of specialty again using machine learning method
Jee Young PARK ; Hyung Min LEE ; Kwang Hyun CHO ; In Byung KIM ; Mi Jin LEE ; Yoo Sang YOON ; Kyung Hye PARK ; Song Yi PARK ; Hong Jae KIM ; Dong Hoon KEY ; Beom Sok SEO ; Young Min JOO ; Chang Gun JEE ; Suk Jae CHOI ; In Hwan YEO ; Ji Hun KANG ; Woo Jin JUNG ; Dae Sung LIM ; Eu Sun LEE
Journal of the Korean Society of Emergency Medicine 2022;33(4):57-66
Objective:
Machine learning is emerging as a new alternative in various scientific fields and is potentially a new method of interpretation. Using the Light Gradient Boosting Machine (LightGBM), we analyzed the factors that influence the rechoice of emergency medicine responders. The survey is a cross-sectional study which provides an accurate understanding of a responder's current status. However, the results may vary depending on the composition, format, and question, and the relationship between the answers may be unclear.
Methods:
This study evaluated the modified 2020 Korean Emergency Physician Survey raw data. We applied the preferred model for random relationship check, random forest, support vector machine, and LightGBM models. The stacking ensemble model was used for the final decision process.
Results:
‘It is fun working in an emergency room’was the most selected response factor for re-choice, followed by ‘interesting major’. The physical burden of age and lack of identity had a negative impact, whereas burnout and emotional stress factors had a lesser effect. Anxiety caused by the coronavirus disease 2019 (COVID-19) is thought to have a significant impact on this decision making.
Conclusion
Establishing the identity of emergency medicine and being faithful to its fundamental mission is a way to increase the rate of re-choice. Decreasing the burden of workload modified according to age is recommended to establish career longevity. The method of machine learning presents us with a new possibility of checking the relevance of survey results quickly and easily.
9.The workload of emergency physician using Korean Emergency Physician Survey
Yoo Sang YOON ; DongWoo SON ; Ji Hun KANG ; Kwang Hyun CHO ; In Byung KIM ; Mi Jin LEE ; Hyung Min LEE ; Kyung Hye PARK ; Song Yi PARK ; Hong Jae KIM ; Dong Hoon KEY ; Beom Sok SEO ; Young Min JOO ; Chang Gun JEE ; Suk Jae CHOI ; In Hwan YEO ; Woo Jin JUNG ; Dae Sung LIM ; Eu Sun LEE
Journal of the Korean Society of Emergency Medicine 2022;33(4):49-56
Objective:
It has been reported that emergency physicians experience high levels of depression and psychological burnout due to night shifts and tend to consider early retirement. This study intended to check working hours and intensity, individual health, satisfaction, and overall welfare, given the increase in the numbers of emergency physicians.
Methods:
The study used the results of the ‘2020 Korean Emergency Physician Survey (KEPS)’ conducted from January 15 to February 26, 2021, which targeted 2,138 emergency physicians registered with the Korean Society of Emergency Medicine. The survey was conducted online through the web and mobile application.
Results:
One thousand three hundred seven out of the 2,167 emergency physicians (60.3%) registered at the society responded. The average age of the respondents was 42.6 years, and there were 1,148 male emergency physicians and 158 female emergency physicians. The average professional experience was 8.2 years, with 325 professors, 122 commissioned doctors, 648 public servants of which 90 had military service, and 45 medical practitioners.
Conclusion
In conclusion, the number of working hours of emergency physicians showed a decreasing trend compared to 2010 and 2015. However, emergency physicians often expected early retirement. This suggests that, while the absolute working hours are decreasing, the actual working intensity has not decreased. For the proper development of the emergency medical system, it is necessary to establish a stable working environment for emergency physicians. A systematic study is needed on the working hours and work intensity of emergency physicians.
10.Analysis of work, life, and occupation perception of emergency physician by generations
Jun Se PARK ; Beom Sok SEO ; Kwang Hyun CHO ; In Byung KIM ; Mi Jin LEE ; Yoo Sang YOON ; Kyung Hye PARK ; Song Yi PARK ; Hong Jae KIM ; Dong Hoon KEY ; Hyung Min LEE ; Young Min JOO ; Chang Gun JEE ; Suk Jae CHOI ; In Hwan YEO ; Ji Hun KANG ; Woo Jin JUNG ; Dae Sung LIM ; Eu Sun LEE
Journal of the Korean Society of Emergency Medicine 2022;33(4):38-48
Objective:
As the history of emergency medicine grows longer, emergency medicine specialists are observed to comprise various age groups. There have been no prior studies on the generation shift analysis of emergency medicine specialists. Our study is designed to identify the characteristics of each generation and predict the generation shift in emergency medicine physicians.
Methods:
The analysis was based on the results of the 2020 survey of emergency medicine specialists. The study was conducted on 1,307 respondents and finally, the responses of 967 people were analyzed after excluding 199 who were not in charge of emergency room treatments and 141 who gave incomplete responses. The respondents were divided into four groups based on the following generations: first generation (1996-1999), second generation (2000-2008), third generation (2009-2014), and fourth generation (2015-2020), classified by the year in which they acquired their emergency medicine board license. The intergenerational difference analysis was done using the Kruskall-Wallis test.
Results:
The first generation was characterized by a high proportion of university hospital professors, large non-clinical activity hours, a few night shifts, higher social contributions, low satisfaction with the training and education environment, and a high retirement age compared to the later generations. In the second generation, the characteristics of the first, third, and fourth generations were generally mixed. The third and fourth generations showed similar characteristics overall, though there were differences in some categories.
Conclusion
There were significant differences by generation in the working environments, motivation for application, and retirement age. This is the first study that quantifies generational differences. Considering these trends, a discussion about the work environment needs to be initiated.

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