Entropymetry for detecting microcracks in high-nickel layered oxide cathodes.

Electric vehicles (EVs) are imposing ever-challenging standards on the lifetime and safety of lithium-ion batteries (LIBs); consequently, real-time nondestructive monitoring of battery cell degradation is highly desired. Unfortunately, high-nickel (Ni) layered oxides, the preferred LIB cathodes for EVs, undergo performance degradation originating from microcrack formation during cycling. Entropymetry is introduced as a real-time analytic tool for monitoring the evolution of microcracks in these cathodes along the state of charge. The entropy change of the layered cathode is associated with the lattice configuration and reflects the structural heterogeneity relevant to the evolution of these microcracks. The structural heterogeneity was correlated with peak broadening in in-situ X-ray diffractometry while varying the experimental conditions that affect crack formation such as the upper cutoff voltage during charging and the Ni-content of the active material. Entropymetry, proposed here as a nondestructive diagnostic tool, can contribute greatly to the safe and reliable operation of LIBs for EVs.

The Preparation and Physiochemical Characterization of Tenebrio molitor Chitin Using Alcalase.

Chitin is mostly produced from crustaceans, but it is difficult to supply raw materials due to marine pollution, and the commonly used chemical chitin extraction method is not environmentally friendly. Therefore, this study aims to establish a chitin extraction process using enzymes and to develop edible insect-derived chitin as an eco-friendly new material. The response surface methodology (RSM) was used to determine the optimal conditions for enzymatic hydrolysis. The optimal conditions for enzymatic hydrolysis by RSM were determined to be the substrate concentration (7.5%), enzyme concentration (80 µL/g), and reaction time (24 h). The solubility and DDA of the mealworm chitosan were 45% and 37%, respectively, and those of the commercial chitosan were 61% and 57%, respectively. In regard to the thermodynamic properties, the exothermic peak of mealworm chitin was similar to that of commercial chitin. In the FT-IR spectrum, a band was observed in mealworm chitin corresponding to the C=O of the NHCOCH3 group at 1645 cm-1, but this band showed low-intensity C=O in the mealworm chitosan due to deacetylation. Collectively, mealworm chitosan shows almost similar physical and chemical properties to commercial chitosan. Therefore, it is shown that an eco-friendly process can be introduced into chitosan production by using enzyme-extracted mealworms for chitin/chitosan production.

Estimation of the Continuous Walking Angle of Knee and Ankle (Talocrural Joint, Subtalar Joint) of a Lower-Limb Exoskeleton Robot Using a Neural Network.

A lower-limb exoskeleton robot identifies the wearer's walking intention and assists the walking movement through mechanical force; thus, it is important to be able to identify the wearer's movement in real-time. Measurement of the angle of the knee and ankle can be difficult in the case of patients who cannot move the lower-limb joint properly. Therefore, in this study, the knee angle as well as the angles of the talocrural and subtalar joints of the ankle were estimated during walking by applying the neural network to two inertial measurement unit (IMU) sensors attached to the thigh and shank. First, for angle estimation, the gyroscope and accelerometer data of the IMU sensor were obtained while walking at a treadmill speed of 1 to 2.5 km/h while wearing an exoskeleton robot. The weights according to each walking speed were calculated using a neural network algorithm programmed in MATLAB software. Second, an appropriate weight was selected according to the walking speed through the IMU data, and the knee angle and the angles of the talocrural and subtalar joints of the ankle were estimated in real-time during walking through a feedforward neural network using the IMU data received in real-time. We confirmed that the angle estimation error was accurately estimated as 1.69° ± 1.43 (mean absolute error (MAE) ± standard deviation (SD)) for the knee joint, 1.29° ± 1.01 for the talocrural joint, and 0.82° ± 0.69 for the subtalar joint. Therefore, the proposed algorithm has potential for gait rehabilitation as it addresses the difficulty of estimating angles of lower extremity patients using torque and EMG sensors.

Enantiomeric CopA3 dimer peptide suppresses cell viability and tumor xenograft growth of human gastric cancer cells.

The CopA3 dimer peptide is a coprisin analog that has an anticancer effect against human cancer cells in vitro. In this study, we investigated the anticancer activity of the enantiomeric CopA3 dimer peptide in human gastric cancer cell lines as well as in an in vivo tumor xenograft model. Enantiomeric CopA3 reduced gastric cancer cell viability and exhibited cytotoxicity against cancer cells. Enantiomeric CopA3-induced cell death was mediated by specific interactions with phosphatidylserine and phosphatidylcholine, membrane components that are enriched in cancer cells, in a calcein leakage assay. Moreover, acridine orange/ethidium bromide staining, flow cytometric analysis, and Western blot analysis showed that enantiomeric CopA3 induced apoptotic and necrotic gastric cancer cell death. The antitumor effect was also observed in a mouse tumor xenograft model in which intratumoral inoculation of the peptide resulted in a significant decrease in the SNU-668 gastric cancer tumor volume. In addition, periodic acid-Schiff and hematoxylin staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay revealed apoptotic and necrotic cell death in tumor masses treated with greater than 150 µg CopA3. Collectively, these results indicate that the enantiomeric CopA3 dimer peptide induces apoptosis and necrosis of gastric cancer cells in vitro and in vivo, indicating that the peptide is a potential candidate for the treatment of gastric cancer, which is a common cause of cancer and cancer deaths worldwide.

Twenty-Five- to Twenty-Seven-Year Results of a Cemented vs a Cementless Stem in the Same Patients Younger Than 50 Years of Age.

BACKGROUND: No study to our knowledge evaluated the long-term survivorship of the contemporary cemented vs cementless stems more than 25 years of follow-up in the same patients younger than 50 years of age. PURPOSE OF STUDY: The purpose of the study is to determine (1) validated outcome scores, (2) prevalence of polyethylene wear and osteolysis, and (3) survivorship of the cemented vs cementless femoral components in the same young patients at minimum follow-up of 25 years. METHODS: We report 171 patients (mean age, 47.7 years) at the time of the surgery who received simultaneous bilateral total hip arthroplasty with a cemented stem in one hip and a cementless stem in the other (26.1-year follow-up). A cementless acetabular component was used in all hips. There were 125 men and 46 women. The mean age at the time of the arthroplasty was 47.7 ± 10.7 years (range, 21-50 years). RESULTS: The average Harris hip scores were similar between the groups of cemented stem (mean, 91 points) and cementless stem (93 points). Survival rate of the acetabular component (79% vs 78%) and that of the femoral component (96% vs 95%) at 26.1 years were similar between the 2 groups. CONCLUSIONS: The long-term fixation of the acetabular metallic shell and cemented or cementless femoral stem was outstanding. Polyethylene wear and periacetabular osteolysis were contributing factors to reduce the long-term survival of the contemporary total hip arthroplasties with or without cement in young patients. New bearing surfaces such as ceramic on ceramic or ceramic on highly cross-linked polyethylene would improve wear of the bearing surfaces.

Antimicrobial peptides in the centipede Scolopendra subspinipes mutilans.

The centipede Scolopendra subspinipes mutilans is an environmentally beneficial and medically important arthropod species. Although this species is increasingly applied as a reliable source of new antimicrobial peptides, the transcriptome of this species is a prerequisite for more rational selection of antimicrobial peptides. In this report, we isolated total RNA from the whole body of adult centipedes, S. subspinipes mutilans, that were nonimmunized and immunized against Escherichia coli, and we generated a total of 77,063 pooled contigs and singletons using high-throughput sequencing. To screen putative antimicrobial peptides, in silico analyses of the S. subspinipes mutilans transcriptome were performed based on the physicochemical evidence of length, charge, isoelectric point, and in vitro and in vivo aggregation scores together with the existence of continuous antimicrobial peptide stretches. Moreover, we excluded some transcripts that showed similarity with both previously known antimicrobial peptides and the human proteome, had a proteolytic cleavage site, and had downregulated expression compared with the nonimmunized sample. As a result, we selected 17 transcripts and tested their antimicrobial activity with a radial diffusion assay. Among them, ten synthetic peptides experimentally showed antimicrobial activity against microbes and no toxicity to mouse erythrocytes. Our results provide not only a useful set of antimicrobial peptide candidates and an efficient strategy for novel antimicrobial peptide development but also the transcriptome data of a big centipede as a valuable resource.

Effect of intrinsic motivation on affective responses during and after exercise: latent curve model analysis.

Understanding the relationship between affect and exercise is helpful in predicting human behavior with respect to exercise participation. The goals of the present study were to investigate individual differences in affective response during and after exercise and to identify the role of intrinsic motivation in affective changes. 30 active male college students (M age = 21.4 yr.) who regularly participated in sports activities volunteered to answer a questionnaire measuring intrinsic motivation toward running activities and performed a 20-min. straight running protocol at heavy intensity (about 70% of VO2max). Participants' affective responses were measured every 5 min. from the beginning of the run to 10 min. after completing the run. Latent curve model analysis indicated that individuals experienced different changes in affective state during exercise, moderated by intrinsic motivation. Higher intrinsic motivation was associated with more positive affect during exercise. There were no significant individual differences in the positive tendency of the participants' affective responses after exercise over time. Intrinsic motivation seems to facilitate positive feelings during exercise and encourages participation in exercise.

An Exploratory Study on the Conceptualization of Burnout among the Professional Esports Athletes: Focused on League of Legends Champions Korea League.

Research on the stress and burnout experienced by athletes in the esports field remains limited, necessitating an approach that considers the unique environment and circumstances of esports athletes. This study aims to explore the conceptualization of burnout experiences among professional esports athletes. The participants included 88 athletes from the League of Legends Championship Korea (LCK). Among these, in-depth interviews were conducted with 7 athletes who had experience in international tournaments (the World Championship), while an open-ended survey was completed by 81 athletes. Data collected through in-depth interviews and an open-ended survey were digitized and utilized for analysis. Through critical review by another author and inductive categorization, the conceptual components of esports athletes' burnout were derived. Through the analysis of 251 raw datum, it was conceptualized into five conceptual factors: performance, overtraining, interpersonal relationships, physical and psychological exhaustion, and career and motivation. The results of this study confirm that esports athletes, like athletes in other conventional sports, experience burnout during their careers, highlighting issues in their unique environment, particularly in aspects of interpersonal relationships and training and rest conditions. This research can serve as a foundational resource for effective athletes' psychological health management in the esports field and underscores the need for further research on burnout among esports athletes.

Oxya chinensis sinuosa (OC) Extracts Protects ARPE-19 Cells against Oxidative Stress via Activation of the Mitogen-Activated Protein Kinases (MAPKs)/ Nuclear Factor-κB (NF-κB) Pathway.

Oxya chinensis sinuosa (OC) is a well-known edible insect. Several researches on the health benefits of OC consumption have been performed to date; however, their effect on eye health remains largely unknown. This study aimed to assess the protective effects of OC extracts on the oxidative stress on the retinal pigment epithelium (RPE) cells. Oxidative damage has been identified as one of the key regulatory factors in age-related macular degeneration. H2O2-induced reactive oxygen species (ROS) production, a well-known oxidative stress factor, can cause cell death in retinal pigment epithelia cells. In this study, we found that three OC extracts effectively prevented H2O2-induced ROS production and subsequent death of ARPE-19 cells in a dose-dependent manner. In addition, the OC extracts inhibited the phosphorylation of mitogen-activated protein kinases including p38, JNK, and ERK. The OC extracts restored IκBα degradation induced by H2O2, indicating that OC extracts suppressed the activation of nuclear factor-κB. Furthermore, the three OC extracts were shown to have antioxidant effects by up-regulating the intracellular expression of key antioxidant proteins such as SOD, NQO, and HO-1. Here we demonstrated the antioxidant and anti-apoptotic effects of the OC extracts on ARPE-19, indicating their potential role in improving eye health. These results suggest that three OC extracts plays a critical role in oxidative stress-induced cell death protects in ARPE-19 cells.

Erratum to: Oxya chinensis sinuosa (OC) Extracts Protects ARPE-19 Cells against Oxidative Stress via Activation of the Mitogen-Activated Protein Kinases (MAPKs)/Nuclear Factor-κB (NF-κB) Pathway.

[This corrects the article DOI: 10.5851/kosfa.2024.e15.].

The Longitudinal Mediating Effect of Smartphone Dependency on the Relationship between Exercise Time and Subjective Happiness in Adolescents.

The phenomenon of adolescents engaging in less physical activity as they age raises several concerns. Among these, we hypothesized that this trend may negatively impact their mental health and smartphone dependency. Thus, the aim of this study was to longitudinally examine the mediating effect of smartphone dependency in the relationship between adolescents' exercise time and subjective well-being. For analysis, publicly available data from the 2018 Korean Children and Youth Panel Survey were utilized, with a total of 2,242 participants' data included in the analysis. Latent growth modeling results revealed a significant linear decrease in adolescents' exercise time and subjective well-being each year, while smartphone dependency exhibited an increasing trend. Furthermore, the significance tests of indirect effects indicated that the mediating effect of the changing trend in smartphone dependency between the changing trends in exercise time and subjective happiness in adolescents was statistically significant. These findings suggest that as grade levels increase, reducing exercise time can lead to higher smartphone dependency among adolescents, ultimately resulting in decreased subjective well-being.

The Mediating Effect of Presenteeism on the Relationship between Emotional Labor and Work Engagement of Coaches for Disability Sports.

The aim of present study was to examine the mediating effect of presenteeism on the relationship between emotional labor and work engagement of coaches for disability sports. A total of 198 coaches in Korea participated in this study. Participants responded a survey measuring emotional labor, presenteeism, and work engagement. After analyzing the correlation between each variable, the mediation model was verified through structural equation model analysis. The results reveal that emotional labor of coaches for disability sports positively predicted their work engagement, but negatively predicted presenteeism. In addition, the participants' presenteeism can have a negative effect on their work engagement. Moreover, completing work in presenteeism was found to mediate the relationship between the deep acting and surface acting in emotional labor and work engagement of disability sports coaches.

Lubricant skin on diverse biomaterials with complex shapes via polydopamine-mediated surface functionalization for biomedical applications.

Implantable biomedical devices require an anti-biofouling, mechanically robust, low friction surface for a prolonged lifespan and improved performance. However, there exist no methods that could provide uniform and effective coatings for medical devices with complex shapes and materials to prevent immune-related side effects and thrombosis when they encounter biological tissues. Here, we report a lubricant skin (L-skin), a coating method based on the application of thin layers of bio-adhesive and lubricant-swellable perfluoropolymer that impart anti-biofouling, frictionless, robust, and heat-mediated self-healing properties. We demonstrate biocompatible, mechanically robust, and sterilization-safe L-skin in applications of bioprinting, microfluidics, catheter, and long and narrow medical tubing. We envision that diverse applications of L-skin improve device longevity, as well as anti-biofouling attributes in biomedical devices with complex shapes and material compositions.

Protaetia brevitarsis seulensis larvae ethanol extract inhibits RANKL-stimulated osteoclastogenesis and ameliorates bone loss in ovariectomized mice.

Modulation of osteoclast formation could be a therapeutic target for inhibiting pathological bone destruction. The receptor activator of nuclear factor (NF)-κB ligand (RANKL) is known to be an essential factor in osteoclast differentiation and activation inducers. However, whether Protaetia brevitarsis seulensis (P. brevitarsis) larvae-a traditional animal-derived medicine used in many Asian countries-can inhibit RANKL-induced osteoclast formation and prevent ovariectomy (OVX)-induced bone loss has not been evaluated. Here, we aimed to investigate the anti-osteoporotic effects of P. brevitarsis larvae ethanol extract (PBE) in RANKL-stimulated RAW264.7 cells and OVX mice. In vitro, PBE (0.1, 0.5, 1, and 2 mg/mL) decreased RANKL­induced tartrate-resistant acid phosphatase (TRAP) activity and expression of osteoclastogenesis-associated genes and proteins. Furthermore, PBE (0.1, 0.5, 1, and 2 mg/mL) significantly inhibited the phosphorylation of p38 and NF-κB. Female C3H/HeN mice were divided into five groups (n = 5 per group), namely, sham-operated, OVX, OVX+PBEL (100 mg/kg, oral gavage), OVX+PBEH (200 mg/kg, oral gavage), and OVX+estradiol (0.03 µg/day, subcutaneous injection). High doses of PBE significantly increased femoral bone mineral density (BMD) and bone volume/tissue volume (BV/TV), whereas femoral bone surface/bone volume (BS/BV) and osteoclastogenesis-associated protein expression decreased compared to those in the OVX group. Moreover, PBE (200 mg/kg) significantly increased estradiol and procollagen type I N-terminal propeptide and decreased N-terminal telopeptide of type I collagen and C-terminal telopeptide of type I collagen compared to those in the OVX group. Our results suggest that PBE can be an effective therapeutic candidate for preventing or treating postmenopausal osteoporosis.

The Effect of Autonomy and Self-Control on Changes in Healthy Lifestyles of Inactive College Students through Regular Exercise.

This study aimed to verify the influence of autonomy and self-control as psychological factors on the changes in lifestyles of inactive college students by participating in regular exercise. A total of 188 university students in Seoul, Korea, taking physical fitness classes for 5 weeks held three times a week participated in the surveys. Surveys were conducted in the first session (T1) and 15th session (T2) of the classes. Autonomy in exercise participation and self-control were measured at T1, and healthy lifestyle was measured at both T1 and T2. A paired t-test was used to measure the changes in healthy lifestyle between two time points, and hierarchical regression analysis was conducted to determine the effect of autonomy in exercise participation and self-control measured at T1 on the healthy lifestyle score at T2. According to the analysis, participants' healthy lifestyles were improved with a statistically significant difference between pre- and post-exercise. Furthermore, the levels of autonomy and self-control before the fitness classes positively influenced the participants' healthy lifestyle after the classes even when the influence of healthy lifestyle measured before the classes was controlled. Thus, it was confirmed that autonomy for participation and self-control are important to change one's healthy lifestyle through regular exercise participation.

Mealworm Ethanol Extract Enhances Myogenic Differentiation and Alleviates Dexamethasone-Induced Muscle Atrophy in C2C12 Cells.

Aging, and other disease-related muscle disorders are serious health problems. Dexamethasone (DEX), a synthetic glucocorticoid, can trigger skeletal muscle atrophy. This study examined the effects of mealworm (Tenebrio molitor larva) ethanol extract (TME) on C2C12 myoblast differentiation and DEX-induced myotube atrophy. TME induced myotube formation compared to the differentiation medium (DM) group. TME also significantly increased the mRNA expression of muscle creatine kinase (CKm) and myogenic regulatory factors (MRFs), such as myogenin (MyoG), myogenic factor (Myf)5, and MRF4 (Myf6). TME dramatically increased the muscle-specific protein, MyoG, compared to the control, whereas the expression of myogenic differentiation 1 (MyoD) remained unchanged. It also activated the mammalian target of rapamycin (mTOR) signaling pathway. In the DEX-induced muscle atrophy C2C12 model, TME reduced the gene expression of atrogin-1, muscle RING finger protein-1 (MuRF-1), and myostatin, which are involved in protein degradation in skeletal muscles. Furthermore, TME elevated the phosphorylation of forkhead box O3 (FoxO3α) and protein kinase B (Akt). These findings suggest that TME can enhance myotube hypertrophy by regulating the mTOR signaling pathway, and can rescue DEX-induced muscle atrophy by alleviating atrophic muscle markers mediated by Akt activation. Thus, TME can be a potential therapeutic agent for treating muscle weakness and atrophy.

The Effect of Changes in Physical Self-Concept through Participation in Exercise on Changes in Self-Esteem and Mental Well-Being.

The aim of the present study was to examine the impact of the changes in physical self-concept induced by exercise participation on the changes in global self-esteem and mental well-being using a structural model analysis. A total of 189 university students in Seoul, Korea, participated in the present study for two waves. The participants responded through a survey measuring physical self-concept, self-esteem, and mental well-being before and after a six-week exercise course. Regression analysis was used to calculate the amount of change in each variable, and the calculated residual scores were used for correlation analysis and structural model analysis. The amounts of changes in the variables are significantly correlated with each other and there was a complementary mediating effect of the changes in self-esteem on the pathway from the changes in physical self-concept to the changes in mental well-being. Physical self-concept changed by exercise participation might directly and positively influence mental well-being, and it can indirectly influence the changes in mental well-being via the improvement of self-esteem.

Predicting Deviant Behaviors in Sports Using the Extended Theory of Planned Behavior.

The purpose of the present study is to examine the deviant behaviors of young athletes the using extended theory of planned behavior (TPB) and impulsivity. About 536 middle and high school athletes in South Korea answered a set of questionnaires that measured their attitude, subjective norms, perceived behavioral control, intention, ethical obligation, and impulsivity. Structural equation model (SEM) analysis revealed that the extended TPB model is adequate to explain deviant behaviors in sports. Further, the underlying intentions that motivate the deviant behaviors of athletes in sports were significantly predicted by perceived behavioral control and moral obligation. Findings also suggested that the intention for deviant behaviors in sports more readily manifests as an actual act when the impulsivity scores are high. Theoretical contributions and practical implications are addressed in the Discussion section.

Motivation and Intention Toward Physical Activity During the COVID-19 Pandemic: Perspectives From Integrated Model of Self-Determination and Planned Behavior Theories.

Background: In attempts to hinder the spread of the Coronavirus disease 2019 (COVID-19), many countries have continued distancing, isolation, and quarantine measures, which has led to limited opportunity of physical activity. This study provides empirical support for a motivational process behind physical activity during the COVID-19 pandemic by testing the influence of psychosocial variables derived from the integrated model of self-determination theory (SDT) and the theory of planned behavior (TPB). Methods: A cross-sectional survey was conducted among Korean adults (N = 248). Participants completed the measures of SDT and TPB constructs modified to reflect their participation in physical activity during the COVID-19 pandemic. A sample size of 243 participants was employed, and the integrated model was tested using serial multiple mediation analysis to check the hypothesized relationships. Results: Findings indicated that in the COVID-19 context, the satisfaction of basic psychological needs positively predicts the level of self-determined motivations for physical activity, which is partially related to the level of social cognitive beliefs and intentions. The findings also demonstrated that attitude toward physical activity during COVID-19 was a major variable explaining the serial multiple relationships between the SDT and TPB constructs. The potential influence of demographics (gender, age, marital status, and past physical activity) was controlled as a covariate, and no significant effects were identified. Conclusion: The current study identified the psychosocial mechanisms of intention of South Koreans' physical activity during the COVID-19 pandemic, which could be used as an empirical basis for the development of interventions to maintain or strengthen physical activity in unprecedented situations.

Anterior Cable Reconstruction Using the Biceps Tendon in Retracted Anterior L-Shaped Rotator Cuff Tears.

Repair of a retracted anterior L-shaped rotator cuff tear is challenging because of the lack of mobilization of the torn tendon and destruction of the rotator cable. Restoring the anterior rotator cable decreases gap formation of the repaired tendon, leading to maintenance of the repair integrity of the anterior supraspinatus tendon. This Technical Note introduces the surgical technique of anterior cable reconstruction using the proximal biceps tendon for a retracted anterior L-shaped rotator cuff tear.