China has the world's second largest tuberculosis epidemic, but progress in tuberculosis control was slow during the 1990s. Detection of tuberculosis had stagnated at around 30% of the estimated total of new cases, and multidrug-resistant tuberculosis was a major problem. These signs of inadequate tuberculosis control can be linked to a malfunctioning health system. The spread of severe acute respiratory syndrome (SARS) in 2003, brought to light substantial weaknesses in the country's public-health system. After the SARS epidemic was brought under control, the government increased its commitment and leadership to tackle public-health problems and, among other efforts, increased public-health funding, revised laws that concerned the control of infectious diseases, implemented the world's largest internet-based disease reporting system, and started a programme to rebuild local public-health facilities. These measures contributed to acceleration in efforts to control tuberculosis. By 2005, the detection of cases of tuberculosis had increased to 80% of the estimated total new cases, permitting China to achieve the 2005 global tuberculosis control targets. At the same time, specific efforts to improve tuberculosis control also contributed to strengthening of the public-health system. We examine how the strengthening of a disease control programme and the public-health system worked together to achieve a desired health outcome.

a b s t r a c tHydraulic fracturing is widely accepted and applied to improve the gas recovery in unconventional reservoirs. Unconventional reservoirs to be addressed here are with very low permeability, complicated geological settings and in-situ stress field etc. All of these make the hydraulic fracturing process a challenging task. In order to effectively and economically recover gas from such reservoirs, the initiation and propagation of hydraulic fracturing in the heterogeneous fractured/ porous media under such complicated conditions should be mastered. In this paper, some issues related to hydraulic fracturing have been reviewed, including the experimental study, field study and numerical simulation. Finally the existing problems that need to be solved on the subject of hydraulic fracturing have been proposed.Unconventional gas mainly includes shale gas, tight gas and coal seam gas. Shale gas is commonly in mudstone, shale and between them the interlayers of sandstone. Tight gas often has been stored in tight sandstone or sometimes limestone. Coal bed methane is contained within coal seams. Their common attribute is that the permeability of the matrix is very low, and the permeability often has been improved by artificial or natural fractures [55]. However, the differences between them are also significant. For example, the effective shale thickness for gas production should be more than 15 m while the height of coal is generally from 0.6 m to 5.0 m [68], as coal seams to be fractured may be multiple and thin, hydraulic fracturing in coal needs to be more accurately designed and controlled. Moreover, the Young's modulus of coal is smaller than shale and tight sandstone, the permeability of coal is more sensitive to stress due to the development of cleat system, and leakoff in coal may be more severe, which can significantly affect the fracturing result. Due to the complexity of unconventional reservoirs, it is challenging to predict the initiation and propagation of hydraulic fractures [39]. For example, the complex in situ stress state and distribution of rocks of varied attributes, which may change the profile of hydraulic fractures [38]; the existence of arbitrary pre-existing interfaces may diversify or arrest hydraulic fractures [93]; the temperature effect [75]; the fluid loss and transport of proppant; the competition between hydraulic fractures, and its recession and closure [4]. Thus, it is crucial to explore how hydraulic fracturing process will happen in complex geological settings.Firsthand materials of hydraulic fracturing come from in-door experiments, and field study. Laboratory study undergoes from small-scale rock samples with several cubic centimetres to large ones with one cubic metre or more. Since it is easy to control the stress conditions and make artificial structures within samples, hydraulic fracturing process with different stress field and rock structures can be conveniently studied. Especially in large scale experiments, it is possible to build a full size borehole, or to contr...

Dispersing metals to the ultrasmall forms is an effective strategy to increase their usage efficiency and catalytic reactivity. [3,4] Recently, atomic dispersion of metal atoms has been realized over the support to form single-atom catalysts (SACs), [4-8] which attract considerable attention due to their maximized metal usage and improved active site homogeneity. [9,10] Because of the high surface energy, single metal atoms are generally formed with the existence of particles or clusters as the byproducts, prohibiting stable atomic dispersion. [11-14] As a result, it is of great importance to find efficient technologies for increasing atomic dispersion while maintaining high stability and catalytic activity during applications. Typically, two strategies are used to disperse SACs stably. One is the bottom-up method, which conventionally refers to single atoms derived from metal ions. Metal ions are captured in electronic and/or structural defects [15-17] of solid matrix such as metal oxide, [18-22] metal carbides, [23,24] zeolites/metal-organic Atomically dispersed catalysts, with maximized atom utilization of expensive metal components and relatively stable ligand structures, offer high reactivity and selectivity. However, the formation of atomic-scale metals without aggregation remains a formidable challenge due to thermodynamic stabilization driving forces. Here, a top-down process is presented that starts from iron nanoparticles, using dual-metal interbonds (RhFe bonding) as a chemical facilitator to spontaneously convert Fe nanoparticles to single atoms at low temperatures. The presence of RhFe bonding between adjacent Fe and Rh single atoms contributes to the thermodynamic stability, which facilitates the stripping of a single Fe atom from the Fe nanoparticles, leading to the stabilized single atom. The dual single-atom Rh-Fe catalyst renders excellent electrocatalytic performance for the hydrogen evolution reaction in an acidic electrolyte. This discovery of dual-metal interbonding as a chemical facilitator paves a novel route for atomic dispersion of chemical metals and the design of efficient catalysts at the atomic scale. The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202003484. Heterogeneous catalysis is pivotal to the modern chemical industry, [1] with many heterogeneous catalysts comprising transition or noble metals deposited over a solid support phase. [2]

Energy storage technologies, such as fuel cells, ammonia production and lithium-air batteries, are important strategies for addressing the global challenge of energy crisis and environmental pollution. Taking overpotential as a direct criterion, we illustrate in theory and experiment that the adsorption energies of charged species such as Li + +e − and H + +e − are a central parameter to describe catalytic activities related to electricity-in/electricity-out efficiencies. The essence of catalytic activity is revealed to relate with electronic coupling between catalysts and charged species. Based on adsorption energy, some activity descriptors such as d-band center, e g -electron number and charge-transfer capacity are further defined by electronic properties of catalysts that directly affect interaction between catalysts and charged species. The present review is helpful for understanding the catalytic mechanisms of these electrocatalytic reactions and developing accurate catalytic descriptors, which can be employed to screen high-activity catalysts in future high-throughput calculations and experiments.

Background:In response to the COVID-19 epidemic, China implemented a series of interventions that impacted tuberculosis (TB) control in the country. Methods: Based on routine surveillance data and questionnaires, the study analyzed TB notification, follow-up examinations, and treatment outcomes. The data were split into three phases in relation to outbreak, lockdown and reopen when the nationwide COVID-19 response started in 2020: control (11 weeks prior), intensive (11 weeks during and immediately after), and regular (4 additional weeks). Data from 2017-2019 were used as baseline. Findings: The notified number of TB patients decreased sharply in the 1 st week of the intensive period but took significantly longer to rebound in 2020 compared with baseline. The percentages of TB patients undergoing sputum examination within one week after 2 months treatment and full treatment course in the intensive period were most affected and decreased by 8% in comparison with control period. 75 • 2% (221/294) of counties reallocated CDC and primary health care workers to fight the COVID-19 epidemic, 26 • 9% (725/2694) of TB patients had postponed or missed their follow-up examinations due to travel restrictions and fear of contracting COVID-19. Interpretation: In the short term, the COVID-19 epidemic mostly affected TB notification and follow-up examinations in China, which may lead to a surge of demand for TB services in the near future. To cope with this future challenge, an emergency response mechanism for TB should be established. Funding: National Health Commission of China-Bill & Melinda Gates Foundation TB Collaboration project (OPP1137180).

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This study investigates the response of marine boundary layer (MBL) cloud properties to aerosol loading by accounting for the contributions of large-scale dynamic and thermodynamic conditions and quantifies the first indirect effect (FIE). It makes use of 19-month measurements of aerosols, clouds, and meteorology acquired during the Atmospheric Radiation Measurement Mobile Facility field campaign over the Azores. Cloud droplet number concentrations N c and cloud optical depth (COD) significantly increased with increasing aerosol number concentration N a . Cloud droplet effective radius (DER) significantly decreased with increasing N a . The correlations between cloud microphysical properties [N c , liquid water path (LWP), and DER] and N a were stronger under more stable conditions. The correlations between N c , LWP, DER, and N a were stronger under ascendingmotion conditions, while the correlation between COD and N a was stronger under descending-motion conditions. The magnitude and corresponding uncertainty of the FIE f5[2› ln(DER)/› ln(N a )] at constant LWPg ranged from 0.060 6 0.022 to 0.101 6 0.006 depending on the different LWP values. Under more stable conditions, cloud-base heights were generally lower than those under less stable conditions. This enabled a more effective interaction with aerosols, resulting in a larger value for the FIE. However, the dependence of the response of cloud properties to aerosol perturbations on stability varied according to whether ground-or satellite-based DER retrievals were used. The magnitude of the FIE had a larger variation with changing LWP under ascending-motion conditions and tended to be higher under ascending-motion conditions for clouds with low LWP and under descending-motion conditions for clouds with high LWP. A contrasting dependence of FIE on atmospheric stability estimated from the surface and satellite cloud properties retrievals reported in this study underscores the importance of assessing all-level properties of clouds in aerosol-cloud interaction studies.