卫生经济学应用于慢性病防控决策的战略研究

为提高当前慢性病防控体系的效率,更好地遏制慢性病的流行,保护公众健康,2015年中国工程院设立了"卫生经济学应用于慢性病防控决策的战略研究"重大咨询项目。课题组调研发现,作为一种重要的卫生决策工具,卫生经济学在慢性病防控决策过程中尚处于初级应用阶段。对卫生经济学的重要性认识不足,对卫生经济学的方法的掌握和应用能力有限,制约了其在慢性病防控决策中的应用,因此建议建立多元主体参与的卫生经济学研究力量,加强卫生经济学应用于慢性病防控决策的大数据积累及应用研究,提出将卫生经济学应用于我国慢性病防控决策的战略框架。     

Experimental and numerical investigations on compressive properties of porous twisted wire materials

Wire diameter, sintering parameter, and porosity have great influences on porous structures and compressive properties of the stainless steel porous twisted wire materials with 30–92% porosities. Finer wires, higher sintering temperature, and longer sintering time will lead to narrower pore-size distributions, more compact porous structures, and stronger compressive yield strength. A random pore model and a twisted wire framework model are put forward to simulate the compressive process. The compressive deformation mechanism is a continuous densification process. The simulated and experimental stress-strain curves all exhibit elastic stage, plastic yield platform stage, and final densification stage.     

Poly(N‐phenylglycine)‐Based Nanoparticles as Highly Effective and Targeted Near‐Infrared Photothermal Therapy/Photodynamic Therapeutic Agents for Malignant Melanoma

Malignant melanoma is a highly aggressive tumor resistant to chemotherapy. Therefore, the development of new highly effective therapeutic agents for the treatment of malignant melanoma is highly desirable. In this study, a new class of polymeric photothermal agents based on poly(N‐phenylglycine) (PNPG) suitable for use in near‐infrared (NIR) phototherapy of malignant melanoma is designed and developed. PNPG is obtained via polymerization of N‐phenylglycine (NPG). Carboxylate functionality of NPG allows building multifunctional systems using covalent bonding. This approach avoids complicated issues typically associated with preparation of polymeric photothermal agents. Moreover, PNPG skeleton exhibits pH‐responsive NIR absorption and an ability to generate reactive oxygen species, which makes its derivatives attractive photothermal therapy (PTT)/photodynamic therapy (PDT) dual‐modal agents with pH‐responsive features. PNPG is modified using hyaluronic acid (HA) and polyethylene glycol diamine (PEG‐diamine) acting as the coupling agent. The resultant HA‐modified PNPG (PNPG‐PEG‐HA) shows negligible cytotoxicity and effectively targets CD44‐overexpressing cancer cells. Furthermore, the results of in vitro and in vivo experiments reveal that PNPG‐PEG‐HA selectively kills B16 cells and suppresses malignant melanoma tumor growth upon exposure to NIR light (808 nm), indicating that PNPG‐PEG‐HA can serve as a very promising nanoplatform for targeted dual‐modality PTT/PDT of melanoma.     

Surface Energy and Surface Stability of Ag Nanocrystals at Elevated Temperatures and Their Dominance in Sublimation‐Induced Shape Evolution

The surface energy and surface stability of Ag nanocrystals (NCs) are under debate because the measurable values of the surface energy are very inconsistent, and the indices of the observed thermally stable surfaces are apparently in conflict. To clarify this issue, a transmission electron microscope is used to investigate these problems in situ with elaborately designed carbon‐shell‐capsulated Ag NCs. It is demonstrated that the {111} surfaces are still thermally stable at elevated temperatures, and the victory of the formation of {110} surfaces over {111} surfaces on the Ag NCs during sublimation is due to the special crystal geometry. It is found that the Ag NCs behave as quasiliquids during sublimation, and the cubic NCs represent a featured shape evolution, which is codetermined by both the wetting equilibrium at the Ag–C interface and the relaxation of the system surface energy. Small Ag NCs (≈10 nm) no longer maintain the wetting equilibrium observed in larger Ag NCs, and the crystal orientations of ultrafine Ag NCs (≈6 nm) can rotate to achieve further shape relaxation. Using sublimation kinetics, the mean surface energy of Ag NCs at 1073 K is calculated to be 1.1–1.3 J m^?2.     

Fast Dynamic Visualizations in Microfluidics Enabled by Fluorescent Carbon Nanodots

Microfluidic systems have become a superior platform for explorations of fascinating fluidic physics at microscale as well as applications in biomedical devices, chemical reactions, drug delivery, etc. Exploitations of this platform are built upon the fundamental techniques of flow visualizations. However, the currently employed fluorescent materials for microfluidic visualization are far from satisfaction, which severely hinders their widespread applications. Here fluorescent carbon nanodots are documented as a game‐changer, applicable in versatile fluidic environment for the visualization in microfluidics with unprecedented advantages. One of the fastest fluorescent imaging speeds up to 2500 frames per second under a normal contionous wave (CW) laser line is achieved by adopting carbon nanodots in microfluidics. Besides better visualizations of the fluid or interface, fluorescent carbon nanodots‐based microparticles enable quantitative studies of high speed dynamics in fluids at microscale with a more than 90% lower cost, which is inaccessible by traditionally adopted fluorescent dye based seeding particles. The findings hold profound influences to microfluidic investigations and may even lead to revolutionary changes to the relevant industries.     

Designing Metallic and Insulating Nanocrystal Heterostructures to Fabricate Highly Sensitive and Solution Processed Strain Gauges for Wearable Sensors

All‐solution processed, high‐performance wearable strain sensors are demonstrated using heterostructure nanocrystal (NC) solids. By incorporating insulating artificial atoms of CdSe quantum dot NCs into metallic artificial atoms of Au NC thin film matrix, metal–insulator heterostructures are designed. This hybrid structure results in a shift close to the percolation threshold, modifying the charge transport mechanism and enhancing sensitivity in accordance with the site percolation theory. The number of electrical pathways is also manipulated by creating nanocracks to further increase its sensitivity, inspired from the bond percolation theory. The combination of the two strategies achieves gauge factor up to 5045, the highest sensitivity recorded among NC‐based strain gauges. These strain sensors show high reliability, durability, frequency stability, and negligible hysteresis. The fundamental charge transport behavior of these NC solids is investigated and the combined site and bond percolation theory is developed to illuminate the origin of their enhanced sensitivity. Finally, all NC‐based and solution‐processed strain gauge sensor arrays are fabricated, which effectively measure the motion of each finger joint, the pulse of heart rate, and the movement of vocal cords of human. This work provides a pathway for designing low‐cost and high‐performance electronic skin or wearable devices.     

Multicolor Photo‐Crosslinkable AIEgens toward Compact Nanodots for Subcellular Imaging and STED Nanoscopy

Aggregation induced emission (AIE) has attracted considerable interest for the development of fluorescence probes. However, controlling the bioconjugation and cellular labeling of AIE dots is a challenging problem. Here, this study reports a general approach for preparing small and bioconjugated AIE dots for specific labeling of cellular targets. The strategy is based on the synthesis of oxetane‐substituted AIEgens to generate compact and ultrastable AIE dots via photo‐crosslinking. A small amount of polymer enriched with oxetane groups is cocondensed with most of the AIEgens to functionalize the nanodot surface for subsequent streptavidin bioconjugation. Due to their small sizes, good stability, and surface functionalization, the cell‐surface markers and subcellular structures are specifically labeled by the AIE dot bioconjugates. Remarkably, stimulated emission depletion imaging with AIE dots is achieved for the first time, and the spatial resolution is significantly enhanced to ≈95 nm. This study provides a general approach for small functional molecules for preparing small sized and ultrastable nanodots.     

Polypyrrole Whelk‐Like Arrays toward Robust Controlling Manipulation of Organic Droplets Underwater

Whelk‐like polypyrrole (PPy) arrays film is successfully prepared by electropolymerization of pyrrole in the presence of low‐surface‐energy tetraethylammonium perfluorooctanesulfonate (TEAPFOS) as dopant. The underwater wettability of PPy whelk‐like arrays can be successfully tuned by electrical doping/dedoping of PFOS ions. Interestingly, CCl₄ droplets with microliter‐size as a representative sample are gathered together to form a larger droplet underwater at the potential of +0.8 V (vs Ag/AgCl), because PPy is in its PFOS‐doped states. Note that CCl₄ droplet can climb uphill successfully on the inclined whelk‐like arrays PPy film under the applied potential of ?1.0 V (vs Ag/AgCl), which may be attributed to wettability gradient derived from different oxidation states of PPy induced by electrochemical potential. These results may provide a simple strategy for on‐demand manipulation of organic droplets underwater at low voltage.