•Temperature in the cooling season was significantly higher than in other seasons and the mid-season environment was similar to the environment of the heating season.•The metabolism of the elderly ...was almost constant when they were seated and wore socks and sweaters.•The elderly prefer warm indoor thermal environments.•The elderly and elderly care centers in Korea have characteristic features; therefore, careful management of the environment in elderly care centers is necessary.
The demand for specialized service facilities for elderly has increased as the population has aged. However, few studies have examined thermal comfort in older people living in these facilities. The aims of this study were (i) to characterize the influence of seasonality on elderly care centers (ECCs) thermal environments; (ii) analyze elderly physical conditions; and (iii) assess indoor environments thermal parameters in Korean ECCs. We administered a survey at 26 ECCs in Korea between April 2013 and March 2014. The questionnaire included thermal sensation votes (TSV), thermal comfort votes, thermal satisfaction votes, clothing insulation, and metabolism. The parameters of measurements were the air temperature, the relative humidity, the globe temperature, and air velocity. Linear regression between TSV and predicted mean vote (PMV) met the ideal case (PMV=TSV) at the origin; however, the slope of the regression equation was lower. Elderly prefer the cooling season, which is warm and slightly hot without air conditioning. Clothing insulation in mid-season was more widespread, diverse, and sensitive to outdoor temperature than it was in other seasons. In addition, metabolism was almost constant. Elderly and ECCs have characteristic features; thus, suitable assessment and more studies on the indoor environment of ECCs are necessary.
This study presents thermal comfort and relevant parameters for kindergarten children in naturally ventilated classrooms in Seoul, Korea. The dry-bulb temperature, relative humidity, the airflow ...velocity, and the globe temperature were measured at 10 randomly selected kindergartens from April to June, 2013, and a survey was conducted three times a day for 119 kindergarten children (age: 4–6) to investigate their thermal comfort, clothing insulation, and metabolism. The effects of these variables on the thermal comfort differential between the model and children were examined to provide basic data for a new PMV model for children. The results were further evaluated through a prediction-based survey of adults (e.g., ISO 7730 and EN 15251). Children were more sensitive to changes in their metabolism than adults, and their preferred temperature was lower than that predicted by the PMV model and the EN 15251. The result of this study would enhance the understanding of thermal comfort of children (age: 4–6) and would contribute to future development of a new PMV model for children.
•Thermal sensations of children were measured in naturally ventilated kindergarten classrooms.•Metabolism and clothing rates (major factors influencing children's thermal sensations) were measured.•Thermal comfort of children was predicted and compared using existing thermal comfort models.
The present study was intended to examine thermal comfort in kindergartens for children aged 4-6 years (preschool children). Centering on Seoul, Korea, thermal comfort characteristics of ...kindergartens in four seasons (spring, summer, autumn, winter) from June 2013 to May 2014 were evaluated. Indoor/outdoor dry-bulb temperatures, relative humidity, air-flow speed, and globe temperatures. The number of kindergartens included in the study were 19, 29, 21 and 16 during spring, summer, autumn and winter, respectively. The study results were derived through a questionnaire survey on TSV (thermal sensation votes) and metabolism conducted with 994 respondents. The relationships between children's clothing insulation and 4-day weighted mean ambient temperatures, operative temperatures, and outdoor temperatures were evaluated and the results indicated that the amount of clothing was changed the most by operative temperatures. The seasonal mean amounts of clothing were 0.29 clo in summer and 0.81 clo in winter, which were smaller than the amount of clothing of adults presented by ASHRAE. The seasonal amounts of clothing for male and female children differed from each other. In addition, children's comfortable temperatures were identified as being lower than those of adults by approximately 0.5 degree C in the summer and by approximately 3.3 degree C in the winter, indicating that children have different thermal awareness from adults.
Particulate matter (PM) samples were collected from inside ten childcare centers, and from their adjacent outdoor environments in Seoul, Korea during the summer, autumn and winter seasons. The ...concentrations and distribution of microbial size of the airborne bacteria and fungi in bio-aerosols were also investigated. The average indoor concentrations of fine particles less than 2.5 μm (PM2.5) in the residential areas ranged from 37.1 μg/m3 (±5.8 μg/m3) to 45.2 μg/m3 (±5.3 μg/m3), while indoor PM2.5 concentrations in centers with roadways nearby ranged from 48.9 μg/m3 (±9.5 μg/m3) to 52.9 μg/m3 (±7.7 μg/m3), and up to 51.1 μg/m3 (±6.4 μg/m3) in residential areas located near construction sites. The concentrations of particulate matter indoor in childcare centers were correlated with the corresponding outdoor locations, in residential areas (R2 of 0.64 for PM10 and 0.66 for PM2.5), near roadways (R2 of 0.72 for PM10 and 0.76 for PM2.5), and near construction areas (R2 of 0.45 for PM10 and 0.62 for PM2.5). The distribution of bio-aerosols showed that 69.4% to 78.1% of the airborne bacteria in the outdoor environments existed in stages 1–3 (over 3.3 μm), while from 59.2% to 78.6% existed in stages 2–4 (2.1–7.0 μm) inside the childcare centers. When the efficiency of air purifiers was compared with the location and characteristics of the indoor of child care centers, the removal efficiency of particulate matter with new data that may characterize indoor air quality.
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•We collected particulate matter and bio-aerosols samples at indoor and outdoor environments of 10 childcare centers.•The distribution of aerodynamic diameter of the airborne bacteria and fungi was investigated.•The correlation coefficient (R2) of particulate matter and associated bio-aerosols were calculated.•The effects of air purifier operation were assessed for indoor air quality in childcare centers.
The relationship between ambient particulate matter exposure and health has been well established. Ultrafine particles (UFP) with a diameter of 100 nm or less are known to increase pulmonary disease ...risk. Biological factors in dust containing UFP can cause severe inflammatory reactions. Pulmonary diseases develop primarily as a result of chronic inflammation caused by immune dysfunction. Thus, this review focuses on the adverse pulmonary effects of biological UFP, principally lipopolysaccharide (LPS), and bacterial extracellular vesicles (EVs), in indoor dust and the pathophysiological mechanisms involved in the development of chronic pulmonary diseases. The impact of LPS-induced pulmonary inflammation is based primarily on the amount of inhaled LPS. When relatively low levels of LPS are inhaled, a cascade of immune responses leads to Th2 cell induction, and IL-5 and IL-13 released by Th2 cells contributes to asthma development. Conversely, exposure to high levels of LPS induces a Th17 cell response, leading to increased production of IL-17, which is associated with asthma, COPD, and lung cancer incidence. Responses to bacterial EV exposure can similarly be broadly divided based on whether one of two mechanisms, either intracellular or extracellular, is activated, which depends on the type of the parent cell. Extracellular bacteria-derived EVs can cause neutrophilic inflammation via Th17 cell induction, which is associated with asthma, emphysema, COPD, and lung cancer. On the other hand, intracellular bacteria-derived EVs lead to mononuclear inflammation via Th1 cell induction, which increases the risk of emphysema. In conclusion, future measures should focus on the overall reduction of LPS sources in addition to the improvement of the balance of inhaled bacterial EVs in the indoor environment to minimize pulmonary disease risk.
The incidence of breast cancer (BC) is increasing in South Korea, and diet is closely related to the high prevalence of BC. The microbiome directly reflects eating habits. In this study, a diagnostic ...algorithm was developed by analyzing the microbiome patterns of BC. Blood samples were collected from 96 patients with BC and 192 healthy controls. Bacterial extracellular vesicles (EVs) were collected from each blood sample, and next-generation sequencing (NGS) of bacterial EVs was performed. Microbiome analysis of patients with BC and healthy controls identified significantly higher bacterial abundances using EVs in each group and confirmed the receiver operating characteristic (ROC) curves. Using this algorithm, animal experiments were performed to determine which foods affect EV composition. Compared to BC and healthy controls, statistically significant bacterial EVs were selected from both groups, and a receiver operating characteristic (ROC) curve was drawn with a sensitivity of 96.4%, specificity of 100%, and accuracy of 99.6% based on the machine learning method. This algorithm is expected to be applicable to medical practice, such as in health checkup centers. In addition, the results obtained from animal experiments are expected to select and apply foods that have a positive effect on patients with BC.
Colorectal cancer (CRC) is the most common type cancers in the world. CRC occurs sporadically in the majority of cases, indicating the predominant cause of the disease are environmental factors. ...Diet-induced changes in gut-microbiome are recently supposed to contribute on epidemics of CRC. This study was aimed to investigate the association of metagenomics and metabolomics in gut extracellular vesicles (EVs) of CRC and healthy subjects. A total of 40 healthy volunteers and 32 patients with CRC were enrolled in this study. Metagenomic profiling by sequencing 16 S rDNA was performed for assessing microbial codiversity. We explored the small molecule metabolites using gas chromatography-time-of-flight mass spectrometry. In total, stool EVs were prepared from 40 healthy volunteers and 32 patients with CRC. Metagenomic profiling demonstrated that bacterial phyla, particularly of Firmicutes and Proteobacteria, were significantly altered in patients with colorectal cancer. Through metabolomics profiling, we determined seven amino acids, four carboxylic acids, and four fatty acids; including short-chain to long chain fatty acids that altered in the disease group. Binary logistic regression was further tested to evaluate the diagnostic performance. In summary, the present findings suggest that gut flora dysbiosis may result in alternation of amino acid metabolism, which may be correlated with the pathogenesis of CRC.
Colorectal cancer (CRC) is the third most common form of cancer and poses a critical public health threat due to the global spread of westernized diets high in meat, cholesterol, and fat. Although ...the link between diet and colorectal cancer has been well established, the mediating role of the gut microbiota remains elusive. In this study, we sought to elucidate the connection between the gut microbiota, diet, and CRC through metagenomic analysis of bacteria isolated from the stool of CRC (n = 89) and healthy (n = 161) subjects. This analysis yielded a dozen genera that were significantly altered in CRC patients, including increased Bacteroides, Fusobacterium, Dorea, and Porphyromonas prevalence and diminished Pseudomonas, Prevotella, Acinetobacter, and Catenibacterium carriage. Based on these altered genera, we developed two novel CRC diagnostic models through stepwise selection and a simplified model using two increased and two decreased genera. As both models yielded strong AUC values above 0.8, the simplified model was applied to assess diet-based CRC risk in mice. Mice fed a westernized high-fat diet (HFD) showed greater CRC risk than mice fed a regular chow diet. Furthermore, we found that nonglutinous rice, glutinous rice, and sorghum consumption reduced CRC risk in HFD-fed mice. Collectively, these findings support the critical mediating role of the gut microbiota in diet-induced CRC risk as well as the potential of dietary grain intake to reduce microbiota-associated CRC risk. Further study is required to validate the diagnostic prediction models developed in this study as well as the preventive potential of grain consumption to reduce CRC risk.
The human microbiota comprises trillions of microbes, and the relationship between cancer and microbiota is very complex. The impact of fecal microbiota alterations on colorectal cancer (CRC) ...pathogenesis is emerging. This study analyzed changes in the microbial composition in CRC subjects with both fecal microbiota and gut microbe-derived extracellular vesicles (EVs). From August 2017 to August 2018, 70 CRC patients and 158 control subjects were enrolled in the study. Metagenomic profiling of fecal microbiota and gut microbe-derived EVs in stool was performed using 16S ribosomal DNA sequencing. Relative abundance, evenness, and diversity in both the gut microbiota and gut microbe-derived EVs were analyzed. Additionally, microbial composition changes according to the stage and location of CRC were analyzed. Microbial composition was significantly changed in CRC subjects compared to control subjects, with evenness and diversity significantly lower in the fecal microbiota of CRC subjects. Gut microbe-derived EVs of stool demonstrated significant differences in the microbial composition, evenness, and diversity in CRC subjects compared to the control subjects. Additionally, microbial composition, evenness, and diversity significantly changed in late CRC subjects compared to early CRC subjects with both fecal microbiota and gut microbe-derived EVs.
Alistipes-
derived EVs could be novel biomarkers for diagnosing CRC and predicting CRC stages.
Ruminococcus
2-derived EVs significantly decreased in distal CRC subjects than in proximal CRC subjects. Gut microbe-derived EVs in CRC had a distinct microbial composition compared to the controls. Profiling of microbe-derived EVs may offer a novel biomarker for detecting and predicting CRC prognosis.
As electronic devices and mainboards become smaller, the need for thermal conductive materials having excellent internal heat dissipation is increasing. In this study, nano thermal grease was ...prepared by mixing in copper nanopowder, which is used as a heat transfer medium in thermal grease, which is a kind of thermal conductive material, with silicon oil. In addition, copper powder was mixed with graphene and alumina, respectively, and the thermal conductivity performance was compared. As a result, the thermal conductivity improved by 4.5 W/m·k over the silicon base, and the upward trend of thermal conductivity increased steadily up to 15 vol. %, and the increasing trend decreased after 20 vol. %. In addition, the increased rate of thermal conductivity from 0 to 5 vol. % and 10 to 15 vol. % was the largest.
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