Background: Ankle flexibility is important for maintaining proper biomechanical function. Static stretching is used to improve flexibility with minimal risk; however, its effects are often temporary. Transfer of energy capacitive and resistive (TECAR) therapy has the potential to enhance muscle flexibility and circulation through deep heat applications. However, comparative studies evaluating the effectiveness of TECAR therapy and static stretching are lacking. Objects: This study aimed to compare the effects of static stretching therapy (ST) and combined TECAR and static stretching therapy (T-ST) in subjects with gastrocnemius muscle (GCM) tightness. Methods: Twenty-seven participants with bilateral GCM tightness were enrolled. To administer the ST and T-ST, which were each applied to both legs, the participants stood for 15 minutes on a wedge with a 0°–15° incline, with both feet on the wedge during ST and with TECAR therapy in resistive energy transfer mode applied to only one side of the GCM during T-ST. Muscle stiffness (MyotonPRO), dorsiflexion range of motion (DF-ROM), peak torque, and pennation angle (PA) of the GCM were measured before and after the intervention. Normality was confirmed using the Shapiro–Wilk test. Differences between the ST and T-ST leg conditions and between pre- and post-intervention changes in the legs were analyzed using paired t-tests. Results: There were no significant differences in any of the measured variables between the legs before the intervention. ST and T-ST legs showed significant improvements in all measured variables after the intervention (p < 0.05). T-ST legs demonstrated a significantly greater increase in DF and a greater decrease in PA than ST legs (p < 0.05). Conclusion: T-ST outperformed ST in reducing PA and increasing DF-ROM by promoting deep tissue relaxation and stimulating metabolic activity. This may lead to reduced pain and greater flexibility compared to ST. Maintaining an optimal PA ensures efficient force transmission during exercise, as evidenced by the observed increase in peak torque.

Background: Chronic low back pain (CLBP) is a common health problem among female caregivers. In Korea, 70.4% of caregivers experience LBP after caregiving. The prevalence of LBP was higher in female caregivers of patients who required physical assistance with transfer than in those caring for patients who did not require physical assistance. Lifting movements, such as patient transfer and positioning, are associated with lumbopelvic stability (LPS) and knee muscle strength. However, no studies have investigated the differences in LPS and knee muscle strength between female caregivers with and without CLBP. Objects: This study was conducted to investigate the differences of the LPS, knee extension strength (KES) and knee flexion strength (KFS) between female caregivers with and without CLBP. Methods: Thirty-one female caregivers participated in this study. Participants were divided into two groups: (1) caregivers without CLBP (n = 13) and (2) caregivers with CLBP (n = 18). LPS, KES, and KFS levels were measured. An independent t-test was used to compare the LPS, KES, and KFS between caregivers with and without CLBP. The statistical significance was set at α of 0.05. Results: The LPS and KES scores were significantly lower in caregivers with CLBP than those without. In contrast, the KFS did not differ significantly between the groups. Conclusion: This study observed associations of both LPS and KES with CLBP among female caregivers.

Sodium sulfate, as a commonly used early strengthening agent, has been widely used in different areas. Because of its sulfonic acid group, sodium sulfate is also used as a cement capillary crystal waterproof material. However, temperature has a significant effect on concrete mixed with sodium sulfate. The effect of sodium sulfate on the early hydration rate at different temperatures was studied by conducting a time and hydration thermal analysis. The effects of sodium sulfate on the mechanical properties of concrete at different temperatures were studied through compressive strength experiments. Impermeability at different temperatures was studied by testing resistance to chloride ion penetration and resistance to water penetration. The effect of resistance to sulfate attack was also experimentally. The hydration products were analyzed by electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The experimental results showed that at low temperature, sodium sulfate can accelerate the early hydration reaction rate, and the effect becomes weaker with increasing temperature. At low temperature, the addition of sodium sulfate can effectively improve the degree of hydration, and enhance the permeability resistance and ion erosion resistance of the matrix.

Mauremys reevesii (Reeves’ turtle) is an endemic freshwater turtle species found throughout East Asia. Due to a rapid population decline, the International Union for Conservation of Nature (IUCN) and the Korean government have classified this species as Endangered (EN). The reported largest population size of M. reevesii in the Republic of Korea was previously estimated to be approximately 20-30 individuals. Our study assessed the population size and structure of M. reevesii at Geumho Reservoir, Republic of Korea, using a capture-recapture data. A total of 433 M. reevesii were incidentally captured during a 35-week trapping process conducted from March to October 2023. The sex ratio of the captured population exhibited a male bias of 1.3 : 1. Sexual size dimorphism was observed only in body weight. Individuals were recaptured up to 11 times during the study period, with males and females being recaptured at an average of 2.1±2.0 times and 1.5±0.9 times, respectively. The estimated population size of M. reevesii in Geumho Reservoir was approximately 891 turtles. The absence of notable sexual size dimorphism and significant sex ratio differences suggests that the population in this area may have been established relatively recently. Compared to previous records, the population in Geumho Reservoir represents the largest single population of M. reevesii, both within the Republic of Korea and globally.

Hydrangea is widely grown as an ornamental plant with a high commercial value owing to its appealing features. Although many cultivars exist as genetic resources, they cannot be effectively used for breeding due to insufficient information regarding their genetic relationships and breeding compatibility. Intraspecific and intergeneric hybridizations within the family, Hydrangeaceae present opportunities to create cultivars with desirable traits, however, breeding efforts in Hydrangea through interspecific hybridization have achieved limited success. The low viability of interspecific hybrids may be attributed to cytogenetic incompatibility between the species. Therefore, a deeper cytogenetic understanding of this genus could enhance future breeding programs. This review focuses on the importance of cytogenetic data in the breeding of hydrangeas and the different cytogenetic techniques utilized in this genus. Future directions for cytogenetic research in Hydrangea are also discussed.

이 연구는 다목적 선박(MPV)의 공기역학적 구조물 설계, 분석 및 향상을 통해 그린 워터 압력에 의한 구조적 안전을 보장하고, 탈탄소화 및 에너지 효율성에 이바지하는 방법을 기술하였다. 유한 요소 분석(FEA)을 통한 초기 평가에서 좌굴 발생에 대한 잠재적인 취약점 이 있음을 확인하였다. 이러한 문제를 해결하기 위해 보강재(Carling stiffener)와 두께 증가를 통하여 응력을 재분배하고 국부적인 좌굴 발생의 위험을 최소화하였다. 보강 후 분석 결과, 한국선급(KR)의 안전 기준인 항복 강도, 미국 선급(ABS) 좌굴 강도 및 노르웨이 표준(NORSOK) 변 위 기준을 모두 충족하는 것이 확인되었다. 결과적으로 고유치 좌굴 해석 결과가 안전 기준을 초과하고 최대 변위가 허용 한계 내에 있는 등 중요한 개선이 이루어졌다. 이러한 개선은 극한의 해양 조건에서 운영 신뢰성을 보장할 수 있다. 이 연구는 공기역학적 항력 감소와 구조적 안전성의 이중적인 이점을 강조하며, 국제 해사 기구(IMO)의 2050 탈탄소화 목표에 부합하는 연료 효율성 및 온실가스 배출 감소에 이바지할 수 있다. 연구 결과는 다양한 선박 유형에 걸쳐 항력 감소 기술을 확장하기 위한 기초 자료를 제공하며, 지속 가능하고 탄력적인 해양 운영을 위한 대안을 제시하였다. 향후 연구는 구조적 안전 평가를 가속할 수 있는 단순화된 모델링 기술 개발에 집중할 것이다.

본 연구는 중국상업은행을 대상으로 COVID-19로 인한 위기를 극복하는 과정에 긍정적인 영향 을 미친 변수가 무엇인지를 분석하였다. 이를 위해 분석표본을 대상으로 맘퀴스트지수 (Malmquist index) 생산성 분석을 실시하여 COVID-19 전후 생산성이 모두 양호했던과 모두 불량했던 그룹 으로 구분한 후, 각 그룹별로 패널 (panel) 분석을 수행하여 수익성 결정요인을 비교하였다. 주요 분석결과는 다음과 같다. COVID-19 전후 지속적으로 높은 생산성을 유지한 중국상업은행 은 자산건전성이 높을수록, 수지비율이 낮을수록, 규모가 작을수록 그리고 이자수익이 높을수록 수 익성에 긍정적인 영향을 발휘하여 COVID-19를 극복한 것으로 확인되었다. 이는 두 그룹 간 생산 성변화 차이가 은행의 경영자원 배분과 경영특성에 의한 것임을 시사한다. 향후 중국상업은행은 수 익구조 개선, 비즈니스 모델의 혁신, 디지털전환에 대한 적극 대응을 해나가야만 지속가능한 성장 을 도모할 수 있을 것이다.

Background: The increasing prevalence of smartphone use has been associated with musculoskeletal pain; however, the specific roles of demographic factors, smartphone usage time, posture, contents and state of addiction on pain in the upper-body regions remain unclear. Objects: This study investigated the influence of smartphone usage characteristics, including age, occupation, visual condition, duration, content, and posture, as well as smartphone addiction, on musculoskeletal pain in upper-body regions. This study aimed to comprehensively elucidate the factors contributing to the pain associated with smartphone use. Methods: A cross-sectional survey was conducted with 316 participants aged 20–59 years. Data on personal characteristics, smartphone use patterns, state of addiction (measured using the Smartphone Addiction Scale-Short Version), and musculoskeletal discomfort (Cornell Musculoskeletal Discomfort Questionnaire and Cornell Hand Discomfort Questionnaire) were collected. Binary logistic regression analysis identified significant predictors of pain in different body regions. Results: Younger age (20–30 years), being housewives or students, and vision impairment (shortsightedness) significantly increased the likelihood of neck, shoulder, and hand pain. Prolonged smartphone use (7–10 hours daily) and gaming were strongly associated with elevated pain risk, whereas moderate usage (1–4 hours daily) may be protect against lumbar pain. Non-neutral postures, especially side lying, have emerged as critical risk factors, with left-side lying linked to hand pain and right-side lying linked to upper back pain. Smartphone addiction consistently predicted pain across all regions by amplifying physical strain through prolonged engagement and poor posture. Conclusion: This study highlighted the multifactorial nature of smartphone-related musculoskeletal pain, emphasizing the roles of demographic characteristics, usage patterns, and addiction. These findings provide a foundation for developing tailored ergonomic and behavioral interventions to mitigate pain risks, particularly in high-use populations. Future research should validate these findings through longitudinal studies and objective measures.

Background: Lower limb strength is crucial for stability and functional movement, such as walking, running, squatting, and balance, with the gluteus maximus (Gmax) being pivotal. Squat exercises are commonly used to strengthen the Gmax; however, the impact of ankle position on muscle activation during squats is not well understood. Objects: This study examined Gmax and lower limb muscle activation patterns in three ankle positions during squats, aiming to optimize rehabilitation strategies and enhance exercise prescriptions. Methods: Surface electromyography recorded the activation levels of the Gmax, vastus medialis oblique (VMO), vastus lateralis oblique (VLO), and biceps femoris (BF) across three ankle positions: neutral (NEU), dorsiflexion (DF), and plantarflexion (PF). A repeated-measures design was employed, involving 30 healthy adults (26 males and 4 females) aged 18–30 years. Muscle activation patterns were statistically analyzed to identify significant variations across these conditions, with the significance level set at p < 0.05. Results: During squats, DF of the ankle joint significantly increased Gmax activation compared with PF and NEU positions, indicating that an ankle position closer to DF may enhance hip extension. In contrast, PF was associated with heightened activation of the VMO and VLO, suggesting that this position may be beneficial for exercises focusing on knee stability. No significant changes were observed in the BF activation across the ankle positions, indicative of its limited involvement in response to variations in ankle positioning. Conclusion: These results underscore the importance of ankle joint positioning in modulating lower-limb muscle engagement during squatting. Ankle DF may be recommended to maximize Gmax activation, which is beneficial for hip-focused strengthening, whereas PF may supports knee stability by targeting quadriceps activation. This study provides evidence for adjusting ankle positioning during squat exercises to optimize specific rehabilitation and performance outcomes.

Background: Limited ankle dorsiflexion (DF) range of motion (ROM) is associated with mechanical dysfunctions and chronic ankle instability. Uphill treadmill walking exercise (UTWE) has the potential to improve ankle mobility and function. Objects: This study aimed to examine the immediate effects of a 15° UTWE on DF ROM and torque generation in patients with limited DF. Methods: The study included 20 adults, comprising 10 males and 10 females, with a mean age 28 years and a passive DF range of 5°–12°. After baseline assessments, participants completed 30 minutes of UTWE on a 15° incline treadmill, followed by post-assessments. DF ROM was evaluated during the stance phase of gait, and in both open-kinematic-chain (OKC) and closed-kinematic-chain (CKC) conditions using a goniometer and Image J software. DF and plantar flexion (PF) peak torque were measured with a Biodex Dynamometer. Results: Post intervention, maximum DF ROM during the stance phase of gait increased significantly from a mean of 8.54° ± 3.97° to 11.03° ± 4.41°. The DF ROM in the OKC and CKC conditions increased significantly from a mean of 8.90° ± 0.62° and 21.55° ± 0.72° to 18.00° ± 1.13° and 28.20° ± 1.00°, respectively (p < 0.0001). DF peak torque increased from 16.20 ± 1.28 N/m to 21.52 ± 1.39 N/m, and PF peak torque increased from 25.26 ± 2.51 N/m to 44.22 ± 4.20 N/m (p < 0.0002). Conclusion: UTWE significantly enhanced DF ROM and ankle torque, indicating that it may be an effective intervention for improving ankle function and preventing injury in clinical and rehabilitation settings.

목적 : 본 연구는 중국 안과병원에 방문한 저도와 중등도 근시 청소년을 연구 대상으로 각막굴절교정 렌즈에 의한 단기간의 근시 진행 억제 효과가 있는지 관찰하고자 하였다. 방법 : J안과에 방문한 근시환자 중 40명의 환자 저도 근시군 20명(40안), 중등도 근시군 20명(40안)을 대상으 로 각막굴절교정 렌즈를 처방하고 6개월 동안 추적 관찰하였다. 각막굴절교정 렌즈 착용 후 1개월, 3개월, 6개월 후 각각 각막굴절교정 렌즈 교정 후 시력과 안축의 길이, 각막곡률, 안압, 각막 중앙 두께 등을 검사하여 분석 및 비교하였다. 통계분석은 SPSS 27.0 소프트웨어를 사용하였다. 결과 : 저도근시군과 중등도근시군의 교정시력이 모두 향상되었으며, 두 군 간의 차이는 통계학적 으로 유의하 였으며, 안축 길이는 중등도근시군의 안축 성장이 작았고, 두 군 간의 차이는 통계학적으로 유의하였다. 각막 곡률 은 중등도 근시 군의 각막 곡률이 더 많이 감소했으며, 두 군 간의 차이는 통계적으로 유의했다. 각막굴절교정 렌 즈를 착용한 환자는 안압과 각막 중앙 두께 측면에서 기준치와 유의한 변화가 없었다. 결론 : 각막굴절교정 렌즈는 청소년의 근시를 효과적으로 교정되었으며, 근시 진행을 억제하는 방법 중 하나로 근시 정도에 따라 차이가 있었다. 또한 청소년들의 근시 통제 효과는 중등도 근시 환자가 저도 근시 환자보다 더 효과적이었다.

Following the previous study, which investigated the pharmacological properties of the Technekitty injection (Tc-99m), the toxicity of a single intravenous administration of the Technekitty injection (Tc-99m) and the side effects that may occur at the diagnostic dose were confirmed. The Technekitty injection (Tc-99m) was administered intravenously once at a dose of 0, 0.67, 2.0, and 6.0 mCi/kg to 5 male and female rats per group. Mortality, general symptom observation, and weight measurement were performed for 2 weeks, followed by observation of autopsy findings. There were no deaths, and no statistically significant weight change was observed. No abnormal systemic signs related to the Technekitty injection (Tc-99m) were observed. These results confirmed that Technekitty injection (Tc-99m) can be safely administered intravenously at doses up to 6.0 mCi/kg. Additionally, technetium-99m at an average dose of 2 mCi (74 MBq) has been verified as a diagnostic dose without adverse effects, allowing the Technekitty injection (Tc-99m) to be used safely without side effects at this dosage. This study demonstrates that the Technekitty injection (Tc-99m) has a wide safety margin, supporting its potential for clinical application. Moreover, these findings align with the nonclinical safety standards for radiopharmaceuticals, reinforcing its utility in veterinary medicine. The Technekitty injection (Tc-99m) is expected to be applicable for clinical diagnosis as a veterinary drug in Korea.

Background: The widespread use of smartphones and personal computers has contributed to a rise in thoracic kyphosis, a condition characterized by excessive outward curvature of the upper back. This condition can lead to reduced lung function, poor posture, and decreased spinal angles, all of which can cause reductions in forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1). Furthermore, these issues are often associated with scapular protraction and anterior tilting. Objects: This study aimed to investigate the effects of using a scapular support pillow in people with thoracic kyphosis, as well as determine the changes in respiratory capacity and postural alignment. Methods: Forty-one participants (25 males and 16 females) with thoracic kyphosis (Cobb angle > 40°) were included in the study. Their respiratory function (FVC, FEV1) and body posture (spinal angle, chest expansion, acromion-to-the-wall index) were measured before and after using the scapular support pillow for approximately 30 minutes. FVC, FEV1, spinal angle, chest expansion, and acromion-to-the-wall index were analyzed using paired-t test. The level of statistical significance was set at p < 0.05. Results: The results demonstrated significant improvements in all measured parameters. Both respiratory function and posture-related metrics showed notable increases after using the scapular support pillow. Conclusion: The use of a scapular support pillow can effectively improve respiratory function and postural alignment in patients with thoracic kyphosis. Our research makes a meaningful contribution by proposing an effortless and convenient treatment option for individuals with thoracic kyphosis.

This study develops a machine learning-based tool life prediction model using spindle power data collected from real manufacturing environments. The primary objective is to monitor tool wear and predict optimal replacement times, thereby enhancing manufacturing efficiency and product quality in smart factory settings. Accurate tool life prediction is critical for reducing downtime, minimizing costs, and maintaining consistent product standards. Six machine learning models, including Random Forest, Decision Tree, Support Vector Regressor, Linear Regression, XGBoost, and LightGBM, were evaluated for their predictive performance. Among these, the Random Forest Regressor demonstrated the highest accuracy with R2 value of 0.92, making it the most suitable for tool wear prediction. Linear Regression also provided detailed insights into the relationship between tool usage and spindle power, offering a practical alternative for precise predictions in scenarios with consistent data patterns. The results highlight the potential for real-time monitoring and predictive maintenance, significantly reducing downtime, optimizing tool usage, and improving operational efficiency. Challenges such as data variability, real-world noise, and model generalizability across diverse processes remain areas for future exploration. This work contributes to advancing smart manufacturing by integrating data-driven approaches into operational workflows and enabling sustainable, cost-effective production environments.

본 연구는 이주배경 청소년의 문화적응 스트레스가 사회적 역량에 영향을 미치는지를 분석하고, 문화적 응 스트레스가 사회적 역량에 미치는 영향에서 문화여가활동의 조절효과를 검증하는 것을 목적으로 하였다. 이를 위해 분석 자료는 한국청소년정책연구원의 ‘다문화청소년패널(MAPS: Multi-cultural Adolescent Panel Study)’ 2기 제1차(2019년) 조사 데이터를 사용하였으며, 연구대상은 이주배경 청소년 총 1,834명 이다. 이에 따른 주요 연구결과는 다음과 같다. 첫째, 문화적응 스트레스는 이주배경 청소년의 사회적 역량 에 부적인 영향을 미치는 것으로 확인되었다. 둘째, 문화여가활동은 이주배경 청소년의 문화적응 스트레스 와 사회적 역량의 관계에서 조절효과를 가지는 것으로 나타났다. 즉, 문화여가활동은 문화적 스트레스가 사회적 역량에 주는 부정적 영향을 완충시켜주는 것으로 나타났다. 이상의 연구결과를 토대로 이주배경 청 소년의 문화적 스트레스 감소시키고 사회적 역량을 향상시키는 문화여가활동을 활성화하는 정책적, 실천적 방안을 제안하였다.

Diamond/SiC composites were prepared by vacuum silica vapor-phase infiltration of in situ silicon–carbon reaction, and the thermophysical properties of the composites were modulated by controlling diamond graphitizing. The effects of diamond surface state and vacuum silicon infiltration temperature on diamond graphitization were investigated, and the micromorphology, phase composition, and properties of the composites were observed and characterized. The results show that diamond pretreatment can reduce the probability of graphitizing; when the penetration temperature is greater than 1600 °C, the diamond undergoes a graphitizing phase transition and the micro-morphology presents a lamellar shape. The thermal conductivity, density, and flexural strength of the composites increased and then decreased with the increase of penetration temperature in the experimentally designed range of penetration temperature. The variation of thermal expansion coefficients of composites prepared with different penetration temperatures ranged from 0.8 to 3.0 ppm/K when the temperature was between 50 and 400 °C.

Silicon carbide (β-SiC) was synthesized through an improved sol–gel method, then Ni/SiC catalysts were prepared using a hydrothermal method. The catalysts were characterized using TEM, H2- TPR, CO2- TPD and N2- TPD, etc. The results showed that the synthesized β-SiC had a large specific surface area, promoting the dispersion of Ni species and thus exposing more active sites. The interaction between Ni species and β-SiC contributed significantly to catalytic performance. Furthermore, the strong alkalinity of catalyst could adjust the bond energy of the active metal and N (M–N), which were conducive to desorption of the recombinant N2 from the metal surface, promoting to ammonia decomposition. Among the Ni/SiC catalysts, 30Ni/SiC-700 synthesized with the Ni loading of 30 wt% and calcination temperature of 700 °C, exhibited the optimal ammonia conversion rate of 93.4% at 600 °C under the space speed of 30,000 mL∙gcat −1∙h−1, and demonstrated a long-term stability, suggesting a very promising catalyst in ammonia decomposition.