다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

OUTPU T 29 OUTPU T 30 OUTPU T 31 OUTPU T 32 OUTPU T 25 OUTPU T 26 OUTPU T 27 OUTPU T 28 OUTPU T 21 OUTPU T 22 OUTPU T 23 OUTPU T 24 OUTPU T 17 OUTPU T 18 OUTPU T 19 OUTPU T 20 OUTPU T 13 OUTPU T 14 OUTPU T 15 OUTPU T 16 OUTPU T 9 OUTPU T 10 OUTPU T 11 OUTPU T 12 OUTPU T 5 OUTPU T 6 OUTPU T 7 OUTPU T 8 OUTPU T 1 OUTPU T 2 OUTPU T 3 OUTPU T 4 29 30 31 32 25 26 27 28 21 22 23 24 17 18 19 20 13 14 15 16 9

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Ozone pollution in China: A review of concentrations, meteorological influences, chemical precursors, and effects

Review of relationship between indoor and outdoor particles: I/O ratio, infiltration factor and penetration factor

This study employs a numerical model to investigate the dispersion characteristics of human exhaled droplets in ventilation rooms. The numerical model is validated by two different experiments prior to the application for the studied cases. Some typical questions on studying dispersion of human exhaled droplets indoors are reviewed and numerical study using the normalized evaporation time and normalized gravitational sedimentation time was performed to obtain the answers. It was found that modeling the transient process from a droplet to a droplet nucleus due to evaporation can be neglected when the normalized evaporation time is <0.051. When the normalized gravitational sedimentation time is <0.005, the influence of ventilation rate could be neglected. However, the influence of ventilation pattern and initial exhaled velocity on the exhaled droplets dispersion is dominant as the airflow decides the droplets dispersion significantly. Besides, the influence of temperature and relative humidity on the dispersion of droplets can be neglected for the droplet with initial diameter <200 microm; while droplet nuclei size plays an important role only for the droplets with initial diameter within the range of 10 microm-100 microm. Practical Implications Dispersion of human exhaled droplets indoor is a key issue when evaluating human exposure to infectious droplets. Results from detailed numerical studies in this study reveal how the evaporation of droplets, ventilation rate, airflow pattern, initial exhaled velocity, and particle component decide the droplet dispersion indoor. The detailed analysis of these main influencing factors on droplet dispersion in ventilation rooms may help to guide (1) the selection of numerical approach, e.g., if the transient process from a droplet to a droplet nucleus due to evaporation should be incorporated to study droplet dispersion, and (2) the selection of ventilation system to minimize the spread of pathogen-laden droplets in an indoor environment.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0668.2009.00626.x

Some questions on dispersion of human exhaled droplets in ventilation room: answers from numerical investigation.

Indoor air quality is essential to public health as people spend most of their time indoors Hence, effective indoor air filtering is under heavy demand to deal with this challenge Metal–organic frameworks (MOFs) have been demonstrated as suitable candidates for air pollution control because of their unique properties, such as large surface area and rich functionalities The integration of MOFs into an organic polymer matrix is considered to be an effective method to control air pollution; however, an efficient and low-cost method to fabricate such filters is still lacking Herein, an immersion method was proposed for embedding the homogenous growth of MOFs into nanofibers with a superior capability of wind resistance without film failure The prepared MOF-filter shows effective PM25 and formaldehyde removal The PM25 filtration efficiency increased from 745% to 872% after integrating ZIF-67 nanocrystals into the electrospun PAN nanofibers Moreover, the PM25 filtration efficiency remains at more than 99% during a long-term test over 30 days The ZIF-67@PAN filter also achieves a formaldehyde removal efficiency of 84% This work not only proposes a scalable and low-cost method for fabricating flexible MOF-nanofiber filters but also holds great promise for improving indoor air quality and reducing the associated health risks

Metal–organic framework-based nanofiber filters for effective indoor air quality control

Background: City-to-city differences have been reported for the increase in short-term mortality associated with a given increase in ozone concentration (ozone mortality coefficient). Although ozone concentrations are monitored at central outdoor locations, a large fraction of total ozone exposure occurs indoors.

Objectives: To clarify the influence of indoor exposure to ozone of outdoor origin on short-term mortality, we conducted an analysis to determine whether variation in ozone mortality coefficients among U.S. cities might be partly explained by differences in total ozone exposure (from both outdoor and indoor exposures) resulting from the same outdoor ozone concentration.

Methods: We estimated average annual air change rates (the overall rate at which indoor air is replaced with outdoor air) and used these to estimate the change in total ozone exposure per unit change in outdoor ozone exposure (ozone exposure coefficient) for 18 cities that had been included in the National Morbidity and Mortality Air Pollution Study (NMMAPS). We then examined associations between both parameters and published ozone mortality coefficients.

Results: For the 18 targeted NMMAPS cities, the association between ozone mortality coefficients and ozone exposure coefficients was strong (1-hr ozone metric: R2 = 0.58, p < 0.001; 8-hr ozone: R2 = 0.56, p < 0.001; 24-hr ozone: R2 = 0.48, p = 0.001). When extended to another 72 NMMAPS cities, the associations remained strong (R2 = 0.47–0.63; p < 0.001).

Conclusions: Differences in ozone mortality coefficients among cities appear to partially reflect differences in total ozone exposure resulting from differences in the amount of outdoor ozone that is transported indoors.

Assessing the Influence of Indoor Exposure to “Outdoor Ozone” on the Relationship between Ozone and Short-term Mortality in U.S. Communities

Background:Seasonal and regional differences have been reported for the increase in short-term mortality associated with a given increase in the concentration of outdoor particulate matter with an aerodynamic diameter smaller than 10 μm (PM10 mortality coefficient). Some of this difference may be be

Chun Chen

Papers

Review of relationship between indoor and outdoor particles: I/O ratio, infiltration factor and penetration factor

Some questions on dispersion of human exhaled droplets in ventilation room: answers from numerical investigation.

Metal–organic framework-based nanofiber filters for effective indoor air quality control

Assessing the Influence of Indoor Exposure to “Outdoor Ozone” on the Relationship between Ozone and Short-term Mortality in U.S. Communities

Indoor exposure to "outdoor PM10": assessing its influence on the relationship between PM10 and short-term mortality in U.S. cities.