To mitigate the serious levels of air pollution in China, the State Council of China issued the Air Pollution Prevention and Control Action Plan (APPCAP) in 2013. This policy is a milestone in air ...quality control in China. We aimed to evaluate the effects of the APPCAP on long-term air quality management and the related health impacts in China.
We did an analysis of national air quality monitoring and mortality data to estimate the health impact of the APPCAP from 2013 to 2017 in 74 key cities in China. Changes in mortality and in years of life lost (YLL), an indicator that considers life expectancy at death, were calculated to assess the health impact of air quality management during the 5-year period.
Between 2013 and 2017, annual average concentrations of PM2·5 decreased by 33·3% (95% CI 16·3–50·3), PM10 by 27·8% (8·0–47·5), sulphur dioxide by 54·1% (28·2–80·0), and carbon monoxide by 28·2% (3·1–53·3) in the 74 key cities. However, no significant change was seen in annual average concentrations of nitrogen dioxide (9·7% reduction; 95% CI −23·0 to 42·4) or ozone (20·4% increase; −30·1 to 71·0). In 2017, as a result of substantial improvements in air quality, there were 47 240 (95% CI 25 870–69 990) fewer deaths and 710 020 (420 230–1 025 460) fewer YLL in the 74 key cities in China than in 2013.
Substantial reductions in mortality and YLL related to control of ambient air pollution were achieved from 2013 to 2017 in China, indicating appreciable effectiveness of China's APPCAP. However, emissions control efforts for ozone and nitrogen dioxide should be strengthened in the future.
National Natural Science Foundation of China and the National Key Research and Development Program of China.
An iterative algorithm, based on recent work in compressive sensing, is developed for volume image reconstruction from a circular cone-beam scan. The algorithm minimizes the total variation (TV) of ...the image subject to the constraint that the estimated projection data is within a specified tolerance of the available data and that the values of the volume image are non-negative. The constraints are enforced by the use of projection onto convex sets (POCS) and the TV objective is minimized by steepest descent with an adaptive step-size. The algorithm is referred to as adaptive-steepest-descent-POCS (ASD-POCS). It appears to be robust against cone-beam artifacts, and may be particularly useful when the angular range is limited or when the angular sampling rate is low. The ASD-POCS algorithm is tested with the Defrise disk and jaw computerized phantoms. Some comparisons are performed with the POCS and expectation-maximization (EM) algorithms. Although the algorithm is presented in the context of circular cone-beam image reconstruction, it can also be applied to scanning geometries involving other x-ray source trajectories.
Objective: In this paper, we review the epidemiological evidence on the relationship between ambient temperature and morbidity. We assessed the methodological issues in previous studies and proposed ...future research directions. Data sources and data extraction: We searched the PubMed database for epidemiological studies on ambient temperature and morbidity of noncommunicable diseases published in refereed English journals before 30 June 2010. Forty relevant studies were identified. Of these, 24 examined the relationship between ambient temperature and morbidity, 15 investigated the short-term effects of heat wave on morbidity, and 1 assessed both temperature and heat wave effects. Data synthesis: Descriptive and time-series studies were the two main research designs used to investigate the temperature-morbidity relationship. Measurements of temperature exposure and health outcomes used in these studies differed widely. The majority of studies reported a significant relationship between ambient temperature and total or cause-specific morbidities. However, there were some inconsistencies in the direction and magnitude of nonlinear lag effects. The lag effect of hot temperature on morbidity was shorter (several days) compared with that of cold temperature (up to a few weeks). The temperature-morbidity relationship may be confounded or modified by sociodemographic factors and air pollution. Conclusions: There is a significant short-term effect of ambient temperature on total and causespecific morbidities. However, further research is needed to determine an appropriate temperature measure, consider a diverse range of morbidities, and to use consistent methodology to make different studies more comparable.
BACKGROUND: Although interest in assessing the impacts of temperature on mortality has increased,few studies have used a case-crossover design to examine nonlinear and distributed lag effects of ...temperature on mortality. Additionally, little evidence is available on the temperature—mortality relationship in China or on what temperature measure is the best predictor of mortality, OBJECTIVES: Our objectives were to use a distributed lag nonlinear model (DLNM) as a part of case crossover design to examine the nonlinear and distributed lag effects of temperature on mortality in Tianjin, China and to explore which temperature measure is the best predictor of mortality. METHODS: We applied die DLNM to a case-crossover design to assess die nonlinear and delayed effects of temperatures (maximum, mean, and minimum) on deaths (nonaccidental, cardiopulmonary,cardiovascular, and respiratory). RESULTS: A U-shaped relationship was found consistently between temperature and mortality. Cold effects (i.e., significantly increased mortality associated with low temperatures) were delayed by 3 days and persisted for 10 days. Hot effects (i.e., significantly increased mortality associated with high temperatures) were acute and lasted for 3 days and were followed by mortality displacement for nonaccidental, cardiopulmonary, and cardiovascular deatiis. Mean temperature was a better predictor of mortality (based on model fit) than maximum or minimum temperature. CONCLUSIONS: In Tianjin, extreme cold and hot temperatures increased the risk of mortality. The effects of cold last longer than the effects of heat. Combining the DLNM and the case-crossover design allows the case-crossover design to flexibly estimate the nonlinear and delayed effects of temperature(or air pollution) while controlling for season.
Purpose
The purpose of the challenge is to find the deep‐learning (DL) technique for sparse‐view computed tomography (CT) image reconstruction that can yield the minimum root mean square error (RMSE) ...under ideal conditions, thereby addressing the question of whether or not DL can solve inverse problems in imaging.
Methods
The challenge setup involves a 2D breast CT simulation, where the simulated breast phantom has random fibro‐glandular structure and high‐contrast specks. The phantom allows for arbitrarily large training sets to be generated with perfectly known truth. The training set consists of 4000 cases where each case consists of the truth image, 128‐view sinogram data, and the corresponding 128‐view filtered back‐projection (FBP) image. The networks are trained to predict the truth image from either the sinogram or FBP data. Geometry information is not provided. The participating algorithms are tested on a data set consisting of 100 new cases.
Results
About 60 groups participated in the challenge at the validation phase, and 25 groups submitted test‐phase results along with reports on their DL methodology. The winning team improved reconstruction accuracy by two orders of magnitude over our previous convolutional neural network (CNN)‐based study on a similar test problem.
Conclusions
The DL‐sparse‐view challenge provides a unique opportunity to examine the state‐of‐the‐art in DL techniques for solving the sparse‐view CT inverse problem.
Highlights • Pollution-induced skin damage is a global problem with particular relevance in China and India. • Ambient particulate matter exposure contributes to premature skin aging. • Ozone ...depletes antioxidants from skin. • Air pollution exerts detrimental effects on healthy and diseased skin. • The arylhydrocarbon receptor is key in mediating air pollution-induced skin damage. • Individuals with sensitive skin may represent a susceptible subgroup. • Specific cosmetic products are required to protect skin from air pollution-induced damage.
We develop a primal-dual algorithm that allows for one-step inversion of spectral CT transmission photon counts data to a basis map decomposition. The algorithm allows for image constraints to be ...enforced on the basis maps during the inversion. The derivation of the algorithm makes use of a local upper bounding quadratic approximation to generate descent steps for non-convex spectral CT data discrepancy terms, combined with a new convex-concave optimization algorithm. Convergence of the algorithm is demonstrated on simulated spectral CT data. Simulations with noise and anthropomorphic phantoms show examples of how to employ the constrained one-step algorithm for spectral CT data.
The energy efficiency of neural signal transmission is thought to be an important constraint in the nervous system. It is generally measured as the energy consumed per unit of information. Most of ...the previous studies have demonstrated this efficiency by focusing on single action potentials. However, neural information is more likely to be encoded by a spike train rather than by a single spike. To date, how the energy efficiency is dependent on patterns of spike trains is still unclear. In this study, we examined the energy efficiency of various firing patterns simulated by the Chay neuron model, including relatively high-frequency activities with massive spikes, medium-frequency activities with a moderate number of spikes, and low-frequency activities with rare spikes. Our results indicate that medium-frequency patterns are more energy efficient than both the high-frequency and low-frequency patterns. The most efficient medium-frequency pattern is a sparse burst firing (SBF) pattern because it consumes minimal energy and transmits an amount of neural information comparable to that of high-frequency patterns which consume much more energy. SBF patterns minimize energy consumption not only by producing fewer spikes than high-frequency patterns, but more importantly, also by consuming available energy sources, namely the potential energy stored in ionic concentration gradients, in a balanced way. Furthermore, with fewer spikes, the irregular spike trains of SBF patterns with short bursts and single spikes maximize the neural information that they carry, leading to higher energy efficiency. Thus, the sensory system may give priority to limiting energy costs over maximizing information to achieve greater energy efficiency.
Epidemiologic studies have reported associations between short-term exposure to particulate matter <2.5 μm in aerodynamic diameter (PM2.5) and mortality, but the role of modifiers remains unclear ...with studies reporting inconsistent results. We evaluated the impact of individual (age, gender and education) and township (geographic area, socioeconomic status, background air pollution and road density) level factors on the relationship between short-term variation in PM2.5 with cause-specific mortality in Beijing (population: 21.7 million in 2016), China.
Daily PM2.5 concentrations in each township (n = 327; township population: 2000–359,400; township area: 1–392 km2) within Beijing were estimated by kriging with external drift using measurements from 35 air quality monitoring stations and geographic variables. Time-stratified case-crossover analysis with township-level mortality data from Oct. 1st, 2012 to Dec. 31st, 2013 was then used to examine associations between PM2.5 exposure estimates and cause-specific mortality, stratified by the potential effect modifiers.
A 10-μg/m3 increase in PM2.5 concentration was associated with a 0.17% 95% confidence interval (CI): 0.05%–0.29% and 0.27% (95%CI:0.01%–0.52%) increase in non-accidental and stroke mortality with no lag, a 0.81% (95%CI:0.39%–1.23%) and 0.96% (95%CI:0.35%–1.57%) increase in respiratory disease (RD) and chronic obstructive pulmonary disease (COPD) mortality at a lag of two-day moving average. For individual-level effect modifiers, the elderly showed higher effects for all the specific causes of mortality; those with lower education level showed higher effects for non-accidental, cardiovascular disease and stroke mortality; females showed higher effects for non-accidental and cause-specific cardiovascular diseases. For township-level effect modifiers, effect estimates tended to be larger for suburban areas, areas of lower road density, lower PM2.5 and lower socioeconomic status.
Short-term exposure to township-level ambient PM2.5 was associated with increased mortality in Beijing, with indications of effect modification by both individual and township-level factors.
•Daily PM2.5 concentrations in each township within Beijing were estimated by kriging with external drift.•Our study provides evidence of associations between township-level ambient PM2.5 and daily cause-specific mortality.•Our findings also provide new information about the modifiers of the effect of PM2.5 on mortality.
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