A longitudinal study on changes in weekend leisure time by age groups in Korea (1999-2019).

BACKGROUND: Data analysis was conducted on 20 years (1999-2019) of the Korean Time Use Survey (KTUS) to identify differences and characteristics among each types by extracting latent clusters of weekend leisure activities. METHODS: Using data from the KTUS, we classified weekend leisure time activities into 6 distinct categories. To identify the latent clusters for each year's KTUS data, we utilized latent profile analysis (LPA). Furthermore, independent samples t-tests and one-way ANOVA were conducted to investigate the characteristics of each latent cluster. RESULTS: As a result of leisure time analysis by survey period, media use accounted for the largest share in all three age groups. The results of the LPA, which included media, sports, culture, and tourism, revealed that the distribution of leisure time for these activities was lower throughout the entire study period. CONCLUSION: Based on the results of this study, it is recommended to explore constructive leisure activities and to develop policy measures to promote the domestic leisure industry and leisure consumption.

A bio-friendly biotin-coupled and azide-functionalized naphthalimide for real-time endogenous hydrogen sulfide analysis in living cells.

Hydrogen sulfide (H2S) is involved in various biological processes. Thereby, abnormal levels of H2S are reported to be related to various human diseases including cancer. Currently, many fluorescent probes are pioneered to detect H2S by taking advantages of naphthalimides' unique internal charge transfer (ICT) property. However, most probes often require a high content of organic solvents or surfactants, and are limited to the analysis of exogenous H2S treated externally in live cell studies, and have difficulties in analyzing endogenous H2S, thus limiting their practical use. In this study, we developed a bio-friendly biotin-coupled and azide-functionalized naphthalimide (1) as a fluorescent probe enabling real-time analysis of H2S in living system. Probe was able to provide a fluorescence at 545 nm via H2S-mediated azide reduction selectively without interference by biologically abundant constituents and pH effects. In a biological study using A549 cells, probe readily penetrated living cells without cytotoxicity, and unreacted probes showed almost no fluorescence, enabling real-time detection of H2S in living cells without requiring separate washing process. More importantly, under stimulation with various H2S inducers and inhibitors, probe was able to provide an effective fluorescence response against fluctuations in endogenous H2S, a key requirement for H2S studies. Probe 1 can be applied as a useful chemical tool and enables the analysis of H2S and the study of H2S-related cell functions in a variety of environments.

Effectiveness of Shock-Absorbing Insole for High-Heeled Shoes on Gait: Randomized Controlled Trials.

This study was carried out to identify the influence of a shock-absorbing insole, developed by the author for use with high-heeled shoes, on walking. The research design included single-blind randomized parallel groups; namely, a group of 26 participants who wore the shock-absorbing insoles and another group of 26 participants who did not wear the insoles, both carried out walking while wearing 7 cm high-heels. During walking, plantar pressure analysis (via in-shoe plantar pressure measurements), surface electrode electromyography (surface EMG), gait analysis, subjective comfort evaluation, and functional movement (functional mobility) analysis were carried out. In order to compare the two groups, statistical verification (paired t-test) was performed. Wearing the shock-absorbing insole with the high-heeled shoes improved posture stability during walking, as well as increasing the walking speed. In addition, the heel pressure, the pressure of the front foot at the inner side, and the shock ability were decreased. For these reasons, the wearers reported higher comfort. Changes in the muscle activities of the tibialis anterior muscle (TA) and the gastrocnemius muscle (GA) heightened the stability of the ankle joints. Overall, the proposed shock-absorbing insole for use with high-heeled shoes improved the postural stability when walking, as well as improving the distribution of pressure on the soles. A decrease in the diverse side-effects of wearing high-heeled shoes can thus be expected.

Life satisfaction analysis between occupational balance (OB) group and occupational imbalance (OI) group.

BACKGROUND AND OBJECTIVES: Occupation and time-use can never be separated because they are important criteria in determining one's lifestyle, improvements of one's lifestyle, and even the quality of life. The purpose of this study was to identify whether there is a difference in time-use between the occupational balance (OB) group and occupational imbalance (OI) group and to determine the factors that influence the life satisfaction of those in the OB group. METHODS: This study sorted detailed activities of 9,228 participants who were over 65 years of age. Raw data of 2014 Korean Time Use Survey (KTUS) were used and the amount of time-use of older adults was classified into eight activity areas. This study classified the amount of time used by older adults for eight occupational areas, namely, activities of daily life (ADLs), instrumental ADL (IADLs), rest and sleep, education, work, play, leisure, and social participation. We identified areas of specific time differences between OB and OI groups, and confirmed variables affecting life satisfaction. RESULTS: The analysis of time-use corresponding to the eight occupational areas showed the greatest time-use for the instrumental activities of daily living, which averaged 1513.59 minutes (56.34%). The largest effect size was social participation (d = 1.38). As a result of analyzing the factors related to the life satisfaction of the OB group, we found that those who were younger (B = 0.02, p < .001), females (B = -0.12, p < .05), had a higher level of education (B = 0.65, p < .001), had a lower need for care (B = -1.19, p < .05), had a higher income (B = -0.43, p < .001), and rural residence (B = 0.29, p < .001) tended to have a higher life satisfaction. CONCLUSIONS: This study may provide a basis for developing time-use management and lifestyle redesign programs.

Cell-specific activation of gemcitabine by endogenous H2S stimulation and tracking through simultaneous fluorescence turn-on.

The endogenous H2S-driven theranostic H2S-Gem has been invented. The theranostic prodrug H2S-Gem is selectively activated in cancer cells, releasing active gemcitabine with a simultaneous fluorescence turn-on. H2S-Gem selectively inhibited cancer cell growth compared to the mother chemotherapeutic gemcitabine. Overall, it is a unique protocol for tracking and transporting chemotherapeutic agents to tumor areas without the guidance of tumor-directive ligands.

Strategies of Detecting Bacteria Using Fluorescence-Based Dyes.

Identification of bacterial strains is critical for the theranostics of bacterial infections and the development of antibiotics. Many organic fluorescent probes have been developed to overcome the limitations of conventional detection methods. These probes can detect bacteria with "off-on" fluorescence change, which enables the real-time imaging and quantitative analysis of bacteria in vitro and in vivo. In this review, we outline recent advances in the development of fluorescence-based dyes capable of detecting bacteria. Detection strategies are described, including specific interactions with bacterial cell wall components, bacterial and intracellular enzyme reactions, and peptidoglycan synthesis reactions. These include theranostic probes that allow simultaneous bacterial detection and photodynamic antimicrobial effects. Some examples of other miscellaneous detections in bacteria have also been described. In addition, this review demonstrates the validation of these fluorescent probes using a variety of biological models such as gram-negative and -positive bacteria, antibiotic-resistant bacteria, infected cancer cells, tumor-bearing, and infected mice. Prospects for future research are outlined by presenting the importance of effective in vitro and in vivo detection of bacteria and development of antimicrobial agents.

Mechanochemistry of Cationic Cobaltocenium Mechanophore.

Recent research on the mechanochemistry of metallocene mechanophores has shed light on the force-responsiveness of these thermally and chemically stable organometallic compounds. In this work, we report a combination of experimental and computational studies on the mechanochemistry of main-chain cobaltocenium-containing polymers. Ester derivatives of the cationic cobaltocenium, though isoelectronic to neutral ferrocene, are unstable in the nonmechanical control experimental conditions that were accommodated by their ferrocene analogs. Replacing the electron withdrawing C-ester linkages with electron-donating C-alkyls conferred the necessary stability and enabled the mechanochemistry of the cobaltocenium to be assessed. Despite their high bond dissociation energy, cobaltocenium mechanophores are found to be selective sites of main chain scission under sonomechanical activation. Computational CoGEF calculations suggest that the presence of a counterion to cobaltocenium plays a vital role by promoting a peeling mechanism of dissociation in conjunction with the initial slipping.

Synthesis of Site-specific Charged Metallopolymers via Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization.

Site-specific cobaltocenium-labeled polymers are synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization using cobaltocenium-labeled chain transfer agents. These chain transfer agents show counterion-dependent solubility. Based on the chemical structure of the chain transfer agents, single cobaltocenium moieties are dictated to be in predetermined locations at either the center or terminals of the polymer chains. Polymerization of hydrophobic monomers (methyl methacrylate, methyl acrylate and styrene) and hydrophilic monomers (2-(dimethylamino)ethyl methacrylate and methacrylic acid) is demonstrated to follow a controlled manner based on kinetic studies. Cobaltocenium-labeled polymers with molecular weights greater than 100,000 Da can be prepared by using a difunctional chain transfer agent. Photophysical properties, electrochemical properties, thermal properties and morphology of the cobaltocenium-labeled polymers are also investigated.

Analysis of Differences in the Degree of Biomechanical Adaptation according to Habituation to Different Heel Heights.

This study aims to comprehensively investigate whether there are any differences in the degree of biomechanical adaptation according to habituation to different heel heights. The biomechanical characteristics of 54 subjects in 3 groups habituated to three heel heights (low, medium-high, and high heels) were evaluated by the measurement of surface EMG, myotonometer (e.g., measurement of muscle tension), foot pressure, and lumbosacral angle, and comparative analysis was carried out to find out whether they showed differences in the comfort visual analog scale (comfort VAS). Wearers of high-heeled shoes (6 cm or more in heel height), in foot pressure comparison, showed significantly high peak pressure in the mask of the hallux, high maximum peak EMG in the gastrocnemius medius (GM), and a high percentage of maximum voluntary isometric contraction (%MVIC) in the plantar flexor. Wearers of low-heeled shoes (3 cm and below in heel height) showed the highest plantar peak pressure in the lateral forefoot and midfoot, the highest contact area in midfoot, the highest %MVIC in the plantar flexion and dorsiflexion of the tibialis anterior (TA), and the highest stiffness in the TA, and they showed the lowest static balance ability with eyes open (EO) among the three groups. It was found that there were significant differences between those habituated to high-heeled shoes and those not habituated to high-heeled shoes and that longtime wearing of high-heeled shoes brings about biomechanical adaptive changes in the human body.

Facial Amphiphilicity-Induced Polymer Nanostructures for Antimicrobial Applications.

New antimicrobial agents are needed to address ever-increasing antimicrobial resistance and a growing epidemic of infections caused by multidrug resistant pathogens. We design nanostructured antimicrobial copolymers containing multicyclic natural products that bear facial amphiphilicity. Bile acid based macromolecular architectures of these nanostructures can interact preferentially with bacterial membranes. Incorporation of polyethylene glycol into the copolymers not only improved the colloidal stability of nanostructures but also increased the biocompatibility. This study investigated the effects of facial amphiphilicity, polymer architectures, and self-assembled nanostructures on antimicrobial activity. Advanced nanostructures such as spheres, vesicles, and rod-shaped aggregates are formed in water from the facial amphiphilic cationic copolymers via supramolecular interactions. These aggregates were particularly interactive toward Gram-positive and Gram-negative bacterial cell membranes and showed low hemolysis against mammalian cells.

Polymerization-Induced Self-Assembly of Metallo-Polyelectrolyte Block Copolymers.

Cobaltocenium-containing polyelectrolyte block copolymer nanoparticles were prepared via polymerization-induced self-assembly (PISA) using aqueous dispersion RAFT polymerization. The cationic steric stabilizer was a macromolecular chain-transfer agent (macro-CTA) based on poly (2-cobaltocenium amidoethyl methacrylate chloride) (PCoAEMACl), and the core-forming block was poly(2-hydroxypropyl methacrylate) (PHPMA). Stable cationic spherical nanoparticles were formed in aqueous solution with low dispersity without adding any salts. The chain extension of macro-CTA with HPMA was efficient and fast. The effects of block copolymer compositions, solid content, charge density, and addition of salts were studied. It was found that the degree of polymerization of both the stabilizer PCoAEMACl and the core-forming PHPMA had a strong influence on the size of nanoparticles.

Rational Synthesis of Metallo-Cations Toward Redox- and Alkaline-Stable Metallo-Polyelectrolytes.

Cations are crucial components in emerging functional polyelectrolytes for a myriad of applications. Rapid development in this area necessitates the exploration of new cations with advanced properties. Herein we describe a combination of computational and experimental design of cobaltocene metallo-cations that have distinct electronic and redox properties. One of the direct outcomes on the first synthesis of a complete set of cation derivatives is to discover highly stable cations, which are further integrated to construct metallo-polyelectrolytes as anion-exchange membranes in solid-state alkaline fuel cells. The device performance of these polyelectrolytes under highly basic and oxidative environments is competitive with many organo-polyelectrolytes.

Crystallization-Driven Self-Assembly of Metallo-Polyelectrolyte Block Copolymers with a Polycaprolactone Core-Forming Segment.

We report crystallization-driven self-assembly (CDSA) of metallo-polyelectrolyte block copolymers that contain cationic polycobaltocenium in the corona-forming block and crystallizable polycaprolactone (PCL) as the core-forming block. Dictated by electrostatic interactions originating from the cationic metalloblock and crystallization of the PCL, these amphiphilic block copolymers self-assembled into two-dimensional platelet nanostructures in polar protic solvents. The 2D morphologies can be varied from elongated hexagons to diamonds, and their stability to fragmentation was found to be dependent on the ionic strength of the solution.

ROMPI-CDSA: ring-opening metathesis polymerization-induced crystallization-driven self-assembly of metallo-block copolymers.

Polymerization-induced self-assembly (PISA) and crystallization-driven self-assembly (CDSA) are among the most prevailing methods for block copolymer self-assembly. Taking the merits of scalability of PISA and dimension control of CDSA, we report one-pot synchronous PISA and CDSA via ring-opening metathesis polymerization (ROMP) to prepare nano-objects based on a crystalline poly(ruthenocene) motif. We denote this self-assembly methodology as ROMPI-CDSA to enable a simple, yet robust approach for the preparation of functional nanomaterials.

The Economic Burden of Stroke Based on South Korea's National Health Insurance Claims Database.

BACKGROUND: This study was conducted to determine the scale and the nature of the economic burden caused by strokes and to use the results as an evidential source for determining the allocation of South Korea stroke cases in 2015. METHODS: For research subjects, the study analyzed demographic characteristics and economic burden based on data from national health insurance (NHI) claims for inpatient and outpatient cases of ischemic stroke and hemorrhagic stroke in 2015 through the Health Insurance Review and Assessment Service (HIRA) and statistical data regarding cause of death from the Korea National Statistical Office (KNSO). This study, in order to estimate economic burden due to stroke, deduced the direct and indirect costs of illness caused by stroke, using cost-of-illness (COI) methods. The economic burden is divided into direct and indirect costs, and indirect cost is estimated by summing lost productivity measured in opportunity cost lost by medical disposition due to a specific disease and lost productivity due to premature death. RESULTS: The total economic burden in Korea due to stroke was US$6.855 billion, that due to ischemic stroke was US$3.658 billion, and that due to hemorrhagic stroke was US$3.197 billion. The average economic burden per stroke case was about US$7247. CONCLUSION: The results of estimating the annual economic burden in all of Korea due to stroke will be used as an evidential source for preparing medical insurance policies, priorities, and plans for arranging medical resources for stroke as well as for determining effective prevention of the disease and related priorities in national health care policies.

Correlation between Leisure Activity Time and Life Satisfaction: Based on KOSTAT Time Use Survey Data.

RATIONALE: This study aims to investigate the correlation between the available leisure activity time and life satisfaction of the healthy elderly and the factors affecting them. METHOD: For the analysis, data from the 2014 Time Use Survey (2014TUS) published by Statistics Korea (KOSTAT) was used. This study classified the detailed activities of 9228 subjects, based on the data in 2014TUS, and analyzed the differences in time use for occupation domains by age group. RESULTS: It was found that a greater amount time used for outdoor leisure activities yielded a higher life satisfaction value. Differences were found in time use by occupation domains between younger and older groups. These showed higher life satisfaction for those with spouses, regular full-time jobs, higher education, and better health. CONCLUSION: Based on these results, in order to improve the quality of life (QoL) for older adults, it is necessary to develop various leisure programs that require dynamic physical activities and to prepare alternative policies at the national level to promote participation in leisure activities by older adults. This study will provide occupational therapists (OTs) with data they can use to help older adults who have difficulty in time usage through time management intervention to improve their life satisfaction and QoL.

A novel role for flotillin-1 in H-Ras-regulated breast cancer aggressiveness.

Elevated expression and aberrant activation of Ras have been implicated in breast cancer aggressiveness. H-Ras, but not N-Ras, induces breast cell invasion. A crucial link between lipid rafts and H-Ras function has been suggested. This study sought to identify the lipid raft protein(s) responsible for H-Ras-induced tumorigenicity and invasiveness of breast cancer. We conducted a comparative proteomic analysis of lipid raft proteins from invasive MCF10A human breast epithelial cells engineered to express active H-Ras and non-invasive cells expressing active N-Ras. Here, we identified a lipid raft protein flotillin-1 as an important regulator of H-Ras activation and breast cell invasion. Flotillin-1 was required for epidermal growth factor-induced activation of H-Ras, but not that of N-Ras, in MDA-MB-231 triple-negative breast cancer (TNBC) cells. Flotillin-1 knockdown inhibited the invasiveness of MDA-MB-231 and Hs578T TNBC cells in vitro and in vivo. In xenograft mouse tumor models of these TNBC cell lines, we showed that flotillin-1 played a critical role in tumor growth. Using human breast cancer samples, we provided clinical evidence for the metastatic potential of flotillin-1. Membrane staining of flotillin-1 was positively correlated with metastatic spread (p = 0.013) and inversely correlated with patient disease-free survival rates (p = 0.005). Expression of flotillin-1 was associated with H-Ras in breast cancer, especially in TNBC (p < 0.001). Our findings provide insight into the molecular basis of Ras isoform-specific interplay with flotillin-1, leading to tumorigenicity and aggressiveness of breast cancer.

Effects of mental practice with action observation training on occupational performance after stroke.

BACKGROUND: Studies on whether mental practice (MP) in patients with stroke using action observation training (AOT) is effective in improving physical performance are still insufficient. To examine the effects of MP on both occupational performance and motor function to complement studies relevant to MP with AOT. METHODS: Subjects of this study were 3 individuals who were diagnosed with stroke. We used an A-B-A study design with follow-up evaluation, which is a type of reversal single experimental research design. A total of 20 experimental sessions were conducted. To assess the long-term effect of MP with AOT, follow-up baseline measurements were made after 2 weeks without MP. Three-dimensional motion analysis and electromyography were conducted during each of the 20 sessions. The Motor Activity Log and Assessment of Motor and Process Skills were measured 3 times: in the pre-MP phase, the post-MP phase, and the 2-week follow-up phase. RESULTS: Occupational performance improved after intervention in all 3 subjects when applying an MP task using AOT. All subjects showed improvement of motor functions, including smoothness of movement, agonistic muscle activation, and co-ordination. The treatment effect continued after 2 weeks. CONCLUSIONS: MP using AOT in patients with stroke is an effective treatment protocol to improve occupational performance and motor function. Thus, MP using AOT may be applicable for treating stroke patients with stroke not only while they are in the hospital but also at home or in the community.

Effect of computer-based cognitive rehabilitation (CBCR) for people with stroke: a systematic review and meta-analysis.

OBJECTIVE: We conducted a systematic review and meta-analysis to identify the effect of computer-based cognitive rehabilitation (CBCR) on improving cognitive functions in patients with stroke. METHODS: Researchers performed a literature search using computerized databases such as the Cochrane Database, EBSCO (CINAHL), PsycINFO, PubMed and Web of Science. The following keywords were used: stroke, computer-based, cognitive rehabilitation, and others. The methodological quality was evaluated. Statistical heterogeneity and standardized mean difference were used to compute the overall effect size and that of subgroups. Also publication bias of the selected studies was analysed. RESULTS: Twelve studies met the inclusion criteria including a total of 461 stroke survivors. Among studies, six RCT studies were rated as high methodological quality. Overall effect size was medium 0.54, and the 95% confidence interval was 0.33-0.74. The effect sizes of acute and chronic phase of stroke were both 0.54. They can be interpreted as medium effect size and were statistically significant. The statistical heterogeneity and publication bias were not significant. CONCLUSION: The present study provides evidence that CBCR is effective on improving cognitive function after stroke. We recommend conducting meta-analysis on subgroups of CBCR programs in further studies.

HER2 induces expression of leptin in human breast epithelial cells.

A close association between the obesity hormone leptin and breast cancer progression has been suggested. The present study investigated the molecular mechanism for enhanced leptin expression in breast cancer cells and its functional significance in breast cancer aggressiveness. We examined whether leptin expression level is affected by the oncoprotein human epidermal growth factor receptor2 (HER2), which is overexpressed in ∼30% of breast tumors. Here, we report, for the first time, that HER2 induces transcriptional activation of leptin in MCF10A human breast epithelial cells. We also showed that p38 mitogen-activated protein kinase signaling was involved in leptin expression induced by HER2. We showed a crucial role of leptin in the invasiveness of HER2-MCF10A cells using an siRNA molecule targeting leptin. Taken together, the results indicate a molecular link between HER2 and leptin, providing supporting evidence that leptin represents a target for breast cancer therapy. [BMB Reports 2012; 45(12): 719-723].