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The electronic industry is facing pressing needs for cooling system with high-performance in heat transfer and matched coefficient of thermal expansion (CTE) with the chips. Metal composite materials (MCMs) with low CTE can be used in cooling chips to overcome the thermal expansion mismatch between the cooling substrate and chips. However, low thermal conductivity of MCMs limits their application in electronic cooling systems. Increasing the percentage of components with high thermal conductivity can enhance the thermal conductivity of MCMs, but it often leads to increase CTE as well. Here, we demonstrate that vapor–liquid phase change can improve the heat transfer performance of tungsten-copper (W-Cu) alloy-based MCMs while maintain their low CTEs. Such strategy reduces the maximum temperature and thermal resistance of MCMs, and also allows for heat spreading from concentrated heat source with high power density. The W-Cu alloy-based vapor chamber (VC) has low thermal resistance of 0.38 K/W at 100 W and high lateral thermal conductivity of ~1727 W/(m·K). The W-Cu alloy-based VC can be readily integrated with the chip and heat sink to serve as cooling substrates for dissipating the heat and simultaneously lowering the thermal expansion mismatch by using its high thermal conductivity and low CTE.

Electrocatalytic water splitting plays a paramount importance role in hydrogen production as a green renewable energy technology. Therefore, development of highly efficient and durable electrocatalysts for oxygen evolution reaction and hydrogen evolution reaction has gained great interest. Self-supported nanoarray electrocatalysts are attracting intense attention owing to larger active areas and lower reaction overpotential than the freestanding particles. Herein, the recent progress with regard to self-supported nanoarray electrocatalysts for water splitting is systematically overviewed, with a special focus on the morphology including 1D, 2D, and heterostructure nanoarrays, as well as the design and preparation strategy of the substrates. Furthermore, the challenges and opportunities of self-supported nanoarray electrocatalysts for water splitting are also discussed. Moreover, the promising application of self-supported nanoarray electrocatalysts in CO2 reduction reaction and nitrogen reduction reaction is also investigated.

The long-term and large-scale soil moisture (SM) record is important for understanding land atmosphere interactions and their impacts on the weather, climate, and regional ecosystem. SM products are one of the parameters used in some earth system models, but these records require evaluation before use. The water resources on the Qinghai-Tibet Plateau (QTP) are important to the water security of billions of people in Asia. Therefore, it is necessary to know the SM conditions on the QTP. In this study, the evaluation metrics of multilayer (0 - 10, 10 - 40 and 40 - 100 cm) SM in different reanalysis datasets of the European Centre for Medium-Range Weather Forecasts interim reanalysis (ERA), National Centers for Environmental Prediction Climate Forecast System and the Climate Forecast System version 2 (CFSv2), and China Meteorological Administration Land Data Assimilation System (CLDAS) are compared with in situ observations at five observation sites, which represent alpine meadow, alpine swamp meadow, alpine grassy meadow, alpine desert steppe, and alpine steppe environments during the thawing season from 1 Jan 2011 to 31 Dec 2013 on the QTP. The ERA SM remains constant at approximately 0.2 m3⋅m-3 at all observation sites during the entire thawing season. The CLDAS and CFSv2 SM products show similar patterns with those of the in situ SM observations during the thawing season. The CLDAS SM product performs better than the CFSv2 and ERA for all vegetation types except the alpine swamp meadow. The results indicate that the soil texture and land cover types play a more important role than the precipitation to increase the biases of the CLDAS SM product on the QTP.

Afforestation is conducive to soil carbon (C) sequestration in semi-arid regions. However, little is known about the effects of afforestation on sequestrations of total and labile soil organic carbon (SOC) fractions in semi-arid sandy lands. In the present study, we examined the effects of Caragana microphylla Lam. plantations with different ages (12- and 25-year-old) on sequestrations of total SOC as well as labile SOC fractions such as light fraction organic carbon (LFOC) and microbial biomass carbon (MBC). The analyzed samples were taken from soil depths of 0–5 and 5–15 cm under two shrub-related scenarios: under shrubs and between shrubs with moving sand dunes as control sites in the Horqin Sandy Land of northern China. The results showed that the concentrations and storages of total SOC at soil depths of 0–5 and 5–15 cm were higher in 12- and 25-year-old C. microphylla plantations than in moving sand dunes (i.e., control sites), with the highest value observed under shrubs in 25-year-old C. microphylla plantations. Furthermore, the concentrations and storages of LFOC and MBC showed similar patterns with those of total SOC at the same soil depth. The 12-year-old C. microphylla plantations had higher percentages of LFOC concentration to SOC concentration and MBC concentration to SOC concentration than the 25-year-old C. microphylla plantations and moving sand dunes at both soil depths. A significant positive correlation existed among SOC, LFOC, and MBC, implying that restoring the total and labile SOC fractions is possible by afforestation with C. microphylla shrubs in the Horqin Sandy Land. At soil depth of 0–15 cm, the accumulation rate of total SOC under shrubs was higher in young C. microphylla plantations (18.53 g C/(m2•a); 0–12 years) than in old C. microphylla plantations (16.24 g C/(m2•a); 12–25 years), and the accumulation rates of LFOC and MBC under shrubs and between shrubs were also higher in young C. microphylla plantations than in old C. microphylla plantations. It can be concluded that the establishment of C. microphylla in the Horqin Sandy Land may be a good mitigation strategy for SOC sequestration in the surface soils.

This work studied the growth of calcium carbonate single crystals on top of the monolayer of Fe3O4@SiO2 nanoparticles (NPs) with added external magnetic field. It showed that the occlusion process of the NPs into calcium carbonate single crystals varies as the force balance on the NPs shifts. Under no or weak magnetic field, the NPs are relatively mobile, the separation force from the substrate on NPs due to the growing calcium carbonate crystals is larger than the attraction force to the substrate by the magnetic field. The complete occlusion of the NPs into the single crystals is therefore observed. As the magnetic field strength increases, the balance shifts toward the attraction force. The mobility of NPs decreases and partial occlusion of the NPs into the single crystals is gradually observed. The findings in this study offer further insight into the occlusion process experienced by the NPs and also potential approach in engineering the force balance for the design and generation of composite materials that occlude foreign materials into their matrix.

Construction of a metal-semiconductor heterojunction is a promising method to improve heterogeneous photocatalysis for various reactions. Although the structure and photocatalytic performance of such a catalyst system have been extensively studied, few reports have demonstrated the effect of interface orientation at the metal-semiconductor junction on junction-barrier bending and the electronic transport properties. Here, we construct a Pt/PbS heterojunction, in which Pt nanoparticles are used as highly active catalysts and PbS nanocrystals (NCs) with well-controlled shapes are used as light-harvesting supports. Experimental results show that the photoelectrocatalytic activities of the Pt/PbS catalyst are strongly dependent on the contacting facets of PbS at the junction. Pt/octahedral PbS NCs with exposed PbS(111) facets show the highest photoinduced enhancement of hydrogen evolution reaction activity, which is ∼14.38 times higher than that of the ones with only PbS(100) facets (Pt/cubic PbS NCs). This enhancement can further be rationalized by the different energy barriers of the Pt/PbS Schottky junction due to the specific band structure and electron affinity, which is also confirmed by the calculations based on density functional theory. Therefore, controlling the contacting interfaces of a metal/semiconductor material may offer an effective approach to form the desired heterojunction for optimization of the catalytic performance.

Two-dimensional (2D) materials have attracted wide attention in photonic, electric, catalysis, and energy fields. Compared to the gas phase synthesis, the liquid phase route enables mass production of 2D materials with relatively low costs. However, these free-standing 2D materials obtained via the wet chemical route have a strong tendency to stack on each other; moreover, their 2D structure and the relevant functions degrade over time. Thus, we developed a strategy to achieve the reversibility of assembly/disassembly in Pd nanosheets (NSs) by utilizing anionic/cationic surfactants. Based on this methodology, the 2D structure of free-standing Pd NSs can be preserved with excellent performances for long-term use. Our results showed that free-standing Pd NSs were extremely unstable and decomposed into nanoparticles in 9 days. However, the assembled Pd NSs stacks maintained their 2D structure and preserved the methanol oxidation reaction (MOR) properties after disassembling.

Solar-driven water evaporation has emerged as a highly efficient solar-thermal process to harness abundant clean solar energy for a variety of important applications. Herein, we rationally designed and developed a high-efficiency and fast-response solar-driven interfacial evaporation system by integrating a paper-based reduced graphene oxide (PrGO) composite membrane on top of a silicone-based porous insulation layer (PIL). The PrGO membrane that was prepared by using a cost-effective, scalable, simple fabrication process could effectively absorb and convert broadband solar light into heat to drive the evaporation process. Simultaneously, the hydrophilic PrGO membrane could provide continuous water supply through its strong capillary wicking effect. The floating PIL not only physically suspends the PrGO membrane but also thermally localizes solar heating at the air–water interface by suppressing downward heat conduction loss. Under one-sun illumination for 30 min, the resultant PrGO-PIL solar-driven interfacial evaporation system achieved steady-state and time-averaged evaporation efficiency of 89.7% and 80.6%, respectively. Theoretical analysis indicates that advantageous thermophysical properties of the evaporating materials together with rational design of the evaporation structure contribute to the superior evaporation performance. Such a high-efficiency solar-driven interfacial evaporation system has enabled consistent high-performance solar desalination of seawater under ambient one-sun illumination.

Elemental composition, dimensionality and morphology are the main factors that influence the catalytic activity and stability of platinum-based and noble metal alloy nanocatalysts. Herein, we present a facile and cost-efficient approach to synthesize ternary alloy Pt–Pd–Ag nanoflowers by co-reduction of the metal precursors in aqueous solutions in a suitable molar ratio, involving hexamethylenetetramine as a structure-directing agent and ascorbic acid as a reducing agent. Both the presence of the aforementioned agents and the interaction between the component metals allow good control over the anisotropic growth of the ternary alloy nanostructure. The as-prepared nanocomposite demonstrates superior electrocatalytic activity towards the oxygen reduction reaction in acidic medium, compared with commercial Pt/C (20 wt%) and Pd/C (10 wt%) catalysts, as well as sufficiently good stability, as demonstrated by the accelerated durability test. The electrocatalytic activity of irregularly shaped nanoparticles of the same elemental composition was also measured, which revealed that the nanoflowers were superior catalysts owing to their specific morphological characteristics. Moreover, the nanoflowers displayed a relatively low electrochemical surface area decay (from 100% to 80.82%) due to their three-dimensional open-framework surface which can limit the aggregation of individual particles.

Superheated solar steam generation above 100 °C is critical for many important applications such as sterilization but is challenging to achieve under natural fluctuating low-flux solar illumination and often requires pressurization and the usage of expensive optical concentrators. Herein, we demonstrate generation of superheated steam under ambient pressure and low-flux solar illumination by integrating a recently emerged interfacial evaporation design into a solar vacuum tube. Within the tube, the water vapor, which is generated by a high-efficiency localized heating-based evaporator, is further heated by a heat exchanger into superheated steam without pressurization. The steam generator has shown tunable steam temperature from 102 to 165 °C and solar-to-steam conversion efficiency from 26 to 49% under 1 sun illumination. Owing to the minimized heat loss from the solar vacuum tube and the interfacial evaporation design, it enables stable generation of steam above 121 °C under ambient fluctuating solar illumination with an averaged solar flux of ∼600 W/m2. Effective sterilization is verified using both the Geobacillus stearothermophilus biological indicator and Escherichia coli bacteria, making portable solar steam sterilization and other steam-related applications feasible under ambient solar illumination.

The biophotonic nanostructures of Morpho butterfly wing display iridescent colors through the combined effect of light diffraction and interference. These nanostructures have attracted wide attention due to their high optical sensitivity and deformable material properties and have been applied to various infrared (IR), volatile organic compound (VOC), and pH sensors. This work explores the application of such biophotonic nanostructures of butterfly wing for acoustic detection and voice recognition. The pressure variation of the acoustic waves induces the vibration of butterfly wing diaphragm, resulting in the periodic change of reflectance. The integrated butterfly wing-based acoustic sensor shows high fidelity in replicating the original acoustic signals. The sensor also demonstrates promise in distinguishing human voices, which provides an alternative approach for voice recognition.

Background As a novel type of isothiocyanate derived from radish seeds from cruciferous vegetables, sulforaphene (SFE, 4-methylsufinyl-3-butenyl isothiocyanate) has various important biological effects, such as anti-oxidative and anti-bacterial effects. Recently, sulforaphene has attracted increasing attention for its anti-tumor effects and its ability to suppress the development of multiple tumors through different regulatory mechanisms. However, it has not yet been widely investigated for the treatment of esophageal cancer. Methods We observed an increased apoptosis in esophageal cancer cells on sulforaphene treatment through flow cytometry (FCM) analysis and transmission electron microscopy (TEM). Through mass spectrometry (MS) analysis, we further detected global changes in the proteomes and phosphoproteomes of esophageal cancer cells on sulforaphene treatment. The molecular mechanism of sulforaphene was verified by western blot,the effect and mechanism of SFE on esophageal cancer was further verified by patient-derived xenograft mouse model. Results We identified multiple cellular processes that were changed after sulforaphene treatment by proteomics. We found that sulforaphene could repress the phosphorylation of CREB through MSK2, leading to suppression of Bcl-2 and further promoted cell apoptosis. Additionally, we confirmed that sulforaphene induces tumor cell apoptosis in mice. Interestingly, we also observed the obvious inhibition of cell migration and invasion caused by sulforaphene treatment by inhibiting the expression of cadherin, indicating the complex effects of sulforaphene on the development of esophageal cancer. Conclusions Our data demonstrated that sulforaphene induced cell apoptosis and inhibits the invasion of esophageal cancer through a mechanism involving the inhibition of the MSK2–CREB–Bcl2 and cadherin pathway. Sulforaphene could therefore serve as a promising anti-tumor drug for the treatment of esophageal cancer.

Oxygen reduction reaction (ORR) is of paramount importance in polymer electrolyte membrane fuel cells due to its sluggish kinetics. In this work, a plasmon-induced hot electrons enhancement method is introduced to enhance ORR property of the silver (Ag)-based electrocatalysts. Three types of Ag nanostructures with differently localized surface plasmon resonances have been used as electrocatalysts. The thermal effect of plasmonic-enhanced ORR can be minimized in our work by using graphene as the support of Ag nanoparticles. By tuning the resonance positions and laser power, the enhancement of ORR properties of Ag catalysts has been optimized. Among these catalysts, Ag nanotriangles after excitation show the highest mass activity and reach 0.086 mA/μgAg at 0.8 V, which is almost 17 times that of a commercial Pt/C catalyst after the price is accounted. Our results demonstrate that the hot electrons generated from surface plasmon resonance can be utilized for electrochemical reaction, and tuning the resonance positions by light is a promising and viable approach to boost electrochemical reactions.

SummaryCorrosion at the nanoscale is vital for the stability of nanoparticles. Understanding the corrosion mechanism can offer insights on how to design more stable nanoparticles during electrocatalysis, such as oxygen reduction reaction (ORR). Here, using a liquid cell (LC) transmission electron microscopy (TEM) technique, we study the corrosion process of palladium@platinum (Pd@Pt) core-shell octahedra at real time. The results revealed that the nanoscale corrosion kinetics was determined synergistically by both the quasi-static factor, local strain, and dynamic factor, local curvature. Specifically, in locations with tensile strain and high local curvature, the etching process is much faster than other places. Density functional theory (DFT) calculation suggested that the dissolution potential of the nanoscale Pd nanocrystal is decreased by the increasement of the strain and meanwhile the calculation indicated that the nanoscale surface Pd atoms trended to be corroded more easily under tensile strain than that under compressive strain. Through the investigation of the nanoscale corrosion mechanisms above, we subsequently designed and synthesized a nanoparticle with smaller strain, which showed higher durability both in in-situ liquid cell and ex-situ ORR stability test.

The heat packs that are based on solid-liquid transition of phase-changing materials (PCMs) have been pursued as a promising way to provide heating for human body comfort and thermotherapy owning to their large heat storage capacity and near-constant heat-release temperature. Current heat packs, however, suffer from leakage, slow charging, and poor heat-release performance due to the flow of liquid PCMs and their low thermal conductivity. Here, we report a strategy for preparing high-performance PCM-based solar thermal heat packs through impregnating organic PCMs within carbon-coated copper foams (CCFs). The porous structure and hydrophobic surface of CCF help to effectively confine the melted liquid PCM within the composite heat pack without leakage. The carbon coating layer efficiently converts the incident solar light into heat, which is rapidly transferred along the three-dimensional thermal conductive network of CCF and stored within the PCM. In the discharging process, the CCF network facilitates the extraction of the heat stored within the PCM. In contrast to neat PCM pack within which only a small portion of PCM that is in contact with human skin contributes to thermal comfort, all PCMs within the CCF-based composite heat pack concertedly release the stored heat. Such release significantly increases the extractable thermal energy and prolongs the usable healing duration for thermotherapy.

Radiative cooling, which normally requires relatively high infrared (IR) emissivity, is one of the insects’ effective thermoregulatory strategies to maintain their appropriate body temperature. Recently, the physical correlation between the delicate biological microstructures and IR emissivity for thermal radiation draws increased attention. Here, a scent patch region on the hindwing of Rapala dioetas butterfly is found to exhibit enhanced IR emissivity compared with the non-scent patch regions. A series of optical simulations are conducted to differentiate the effect of biological structures and material composition on the high IR emissivity. Besides the intrinsic IR absorption (emission) of chitin (the main composition of butterfly wings), the hierarchical microstructures of the scent patch scale further improve the IR absorption (emission) through the increased inner surface area and multi-scattering effect. This enhancement of IR emissivity enables the butterfly to efficiently radiate heat from the scent patch region to the environment with a limited volume of chitin. This study of the correlation between IR emissivity and microstructural designs may offer additional pathways to engineer bioinspired materials and systems for radiative cooling applications.

Here, we prepare a ternary hydroxide composite (NiCo2CrX-OH) by a simple one-step hydrothermal method, and the effect of the ratio of Cr on the final composite morphology and electrochemical performance are systematically studied. We find that NiCo2Cr1.5-OH in 6 M KOH has the best electrochemical performance, the mass capacitance is 1101 F g−1 at a current density of 0.5 A g−1, and the specific capacitance of NiCo2–OH under the same conditions is 323.7 F g−1. A biomass activated carbon with a porous structure is prepared by the KOH activation method with one-off chopsticks, and it has a specific capacitance of 422.0 F g−1 at 0.5 A g−1. Using this carbon as the negative electrode material and NiCo2Cr1.5-OH as the positive electrode material, an asymmetric supercapacitor is assembled and it has an energy density of 33.6 Wh kg−1 (power density, 374.6 W kg−1) when the current density is 0.5 A g−1 in 6 M KOH. To prevent the leakage of the electrolyte in the actual application process, the prepared gel electrolyte is used instead of aqueous electrolyte.

Porous carbon materials have proven to be an excellent candidate electrode material for supercapacitor applications; however, the energy density is relatively in a low level. In this work, we introduce gold nanoparticles into the precursor of polyacrylonitrile to prepare composite materials of gold nanoparticles and porous carbon using a facile method to enhance the energy density of this carbon based supercapacitor device. The samples are quantitatively analyzed using transmission electron microscope, field emission scanning electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy in order to unveil the structure and morphological features. Accordingly, the results have confirmed the porous structure, including numerous micro/mesoporous, with relatively high specific surface area at 3, 305 m2/g. On the electrochemical analysis aspect, the composite materials demonstrated a high specific capacitance of 421.4 F/g at the current density of 0.5 A/g, which is much higher than that of the pristine carbon (without introducing gold nanoparticles), 190 F/g, indicating the optimized nature of the composite materials. Moreover, the symmetrical supercapacitor is assembled with composite electrode, and meshed with 6 M KOH aqueous solution as an electrolyte. Interestingly, a high specific energy of 10.4 Wh/kg is obtained at specific power of 124.9 W/kg. According to the findings, the obtained composite electrode material of gold nanoparticles and porous carbon is a highly promising electrode material for supercapacitors or other energy storage devices.

Nano-structured composite materials of Ni3S2/MnS2 at carbon are synthesized by a one-step carbonization and vulcanization. The morphology of the composites is controlled by adjusting the ratio of aniline and ammonium persulfate (both as an initiator and a sulfur source). The nanocomposite material has a porous structure stacked by sheets, which can expose more active sites; in the meantime, the porous structure is conducive to the rapid transfer of electrolyte ions. Furthermore, the synthesized nanocomposite material can be used as anode materials for supercapacitor, which has a wide potential window from -1.1 to 0.2 V and shows high specific capacitance of 291 F g−1 at 0.5 A g−1 in 6 M KOH. The asymmetric supercapacitors further assembled with Ni(OH)2 as cathode materials has a specific capacitance of 67 F g−1 at 0.5 A g−1 and good cyclic stability (capacitance retention of 74.5% over 2000 cycles). The electrochemical properties of asymmetric supercapacitors deliver a maximum energy density of 18.8 Wh kg−1 at power density of 360.8 W kg−1. It indicates that this kind of nanocomposite material is a very promising negative material for supercapacitors with excellent electrochemical performance.

BACKGROUND: The present study aimed to investigate the current situation and future trends of online academic activities for oncologists during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: From April 22 to May 5, 2020, a multicenter survey was conducted using an online questionnaire platform. To compare categorical variables, χ(2)-test, the kappa consistency analysis, and Wilcoxon rank sum test were applied. For all statistical hypotheses, P

The plasmonic heating effect of noble nanoparticles has recently received tremendous attention for various important applications. Herein, we report the utilization of interfacial plasmonic heating-assisted evaporation for efficient and facile solar-thermal energy harvest. An airlaid paper-supported gold nanoparticle thin film was placed at the thermal energy conversion region within a sealed chamber to convert solar energy into thermal energy. The generated thermal energy instantly vaporizes the water underneath into hot vapors that quickly diffuse to the thermal energy release region of the chamber to condense into liquids and release the collected thermal energy. The condensed water automatically flows back to the thermal energy conversion region under the capillary force from the hydrophilic copper mesh. Such an approach simultaneously realizes efficient solar-to-thermal energy conversion and rapid transportation of converted thermal energy to target application terminals. Compared to conventional external photothermal conversion design, the solar-thermal harvesting device driven by the internal plasmonic heating effect has reduced the overall thermal resistance by more than 50% and has demonstrated more than 25% improvement of solar water heating efficiency.

Reusing polluted water through various decontamination techniques has appeared as one of the most practical approaches to address the global shortage of clean water. Rather than relying on single decontamination mechanism, herein we report the preparation and utilization of paper-based composites for multifunctional solar-driven clean water generation that is inspired by the multiple water purification approaches in biological systems. The reduced graphene oxide (rGO) sheets within such composites can efficiently remove organic contaminants through physical adsorption mechanism. Under solar irradiation, the floating rGO composites can instantly generate localized heating, which not only can directly generate clean water through distillation mechanism but also significantly enhance adsorption removal performance with the assistance of upward vapor flow. Such porous-structured paper-based composites allow for facile incorporation of photocatalysts to regenerate clean water out of contaminated water with combined adsorption, photodegradation, and interfacial heat-assisted distillation mechanisms. Within a homemade all-in-one water treatment device, the practical applicability of the composites for multifunctional clean water generation has been demonstrated.

In this work, we report the fabrication and thermal performance evaluation of flexible heat pipes prepared by using a fluororubber tube as the connector in the adiabatic section and using strong base treated hydrophilic copper meshes as the wick structure. Deionized water was chosen as working fluid and three different filling ratios (10%, 20%, and 30%) of working fluid were loaded into the heat pipe to investigate its impact on thermal performance. The fabricated heat pipes can be easily bended from 0o to 180o in the horizontal operation mode and demonstrated consistently low thermal resistances after repeated bending. It was found that with optimized amount of working fluid, the thermal resistance of flexible heat pipes increased with larger bending angles. Theoretical analysis reveals that bending disturbs the normal vapor flow from evaporator to condenser in the heat pipe, thus leads to increased liquid–vapor interfacial thermal resistance in the evaporator section. The flexible heat pipes have been successfully applied for thermal control of foldable electronic devices showing superior uniform heat-transfer performance.

Labile soil organic matter (SOM) plays a crucial role in nutrient and carbon cycling, particularly in permafrost ecosystems. Understanding its variation is therefore very important. In the present study, we evaluated the seasonal patterns of labile SOM from April 2013 to March 2014 under alpine swamp meadow (ASM), meadow (AM), steppe (AS) and desert (AD) vegetation in permafrost regions of the China's Qinghai–Tibet Plateau. The fractions (0 to 10 cm depth) included dissolved organic carbon (DOC), light-fraction carbon (LFC) and nitrogen (LFN), and microbial biomass carbon (MBC) and nitrogen (MBN). These fractions showed dramatic seasonal patterns in ASM and AM soils, but were relatively stable in AD soil. Soil DOC concentrations in the ASM, AM, and AD soils increased from April to May 2013, then increased again from July to August 2013 and from February to March 2014. The LFC and LFN concentrations in all four vegetation types were higher from June to August 2013. The highest MBC and MBN concentrations in the ASM, AM, and AS soils all occurred in the summer and the ASM soil showed a second peak in October or November 2013. Seasonal changes in climatic factors, vegetation types, and permafrost features were great causes of labile SOM variations in this study. Throughout the entire sampling period, the ASM soil generally had the highest labile SOM, followed by the AM, AS, and AD soils; thus, the ASM soil is the best system conserving soil nutrient (especially labile fractions) and microbial activity. Correlation analysis indicated that these fractions were not related to soil moisture and temperature in AS or AD soils, but soil temperature and moisture were significantly related to MBC and MBN in AM soil and DOC in ASM soil. Thus, the response of the labile SOM fractions in this high-altitude permafrost soils to climate change depended strongly on vegetation types.

Poor dispersion stability has become one of the major obstacles to the practical application of thermal nanofluids, especially for silicone-oil-based nanofluids that are used at relatively high operating temperatures. Herein, by using Fe3O4 nanofluid as a model system, we report a facile and effective strategy to prepare stably dispersed silicone-oil-based nanofluids that enable high-temperature operation. The strategy involves a series of processes, including controlled high-temperature synthesis of nanoparticles, surface modification of particles, and post-modification particle size partition. The solvothermally synthesized particles not only possess high thermal stability, but also allow for easy surface modification through ligand exchange. Phosphate-terminated polydimethylsiloxane ligands, which simultaneously possess high compatibility with silicone-oil-based fluid and high temperature stability, were used to exchange synthetic ligands and robustly anchor onto the particle surfaces, offering effective screening of the interparticle attraction. After centrifugal removal of the large-sized surface-modified particles, the prepared nanofluids have demonstrated stable dispersion at temperatures slightly lower than the particle synthesis temperature. The stably dispersed Fe3O4/silicone-oil nanofluids have been successfully utilized for consistent volumetric harvesting of solar thermal energy at more than 110 °C.

The natural world exhibits numerous examples of efficient optical designs with novel hierarchical microstructures and specialized functionality after millions of years of evolution. Materials scientists have long been deriving understanding and inspiration from nature's optical ingenuity, such as vivid structural colors, light antireflection, light focusing, and chirality. Progress in engineering bioinspired optical functional materials has been exciting in the past years. In this review, the focus is on the state-of-the-art achievements of bioinspired optical materials with applications in various areas including efficient light manipulation, optical sensors, light–energy conversion, plasmonic materials with ultrahigh surface plasmon resonance (SPR) efficiency and metamaterials. The major challenges and perspectives for bioinspired designs of optical functional materials in the future are also briefly addressed.

Solving the problems of water pollution and water shortage is an urgent need for the sustainable development of modern society. Different approaches, including distillation, filtration, and photocatalytic degradation, have been developed for the purification of contaminated water and the generation of clean water. In this study, we explored a new approach that uses solar light for both water purification and clean water generation. A bifunctional membrane consisting of a top layer of TiO2 nanoparticles (NPs), a middle layer of Au NPs, and a bottom layer of anodized aluminum oxide (AAO) was designed and fabricated through multiple filtration processes. Such a design enables both TiO2 NP-based photocatalytic function and Au NP-based solar-driven plasmonic evaporation. With the integration of these two functions into a single membrane, both the purification of contaminated water through photocatalytic degradation and the generation of clean water through evaporation were demonstrated using simulated solar illumination. Such a demonstration should also help open up a new strategy for maximizing solar energy conversion and utilization.

Background Stroke is often regulated by a number of modifiable and nonmodifiable risk factors. Recently, studies suggested high gamma-glutamyltransferase (GGT) level may be associated with stroke, but drew inconsistent conclusions. So, we conducted a meta-analysis to evaluate the relationship between GGT level and risk of stroke. Methods We systematically searched PubMed, Embase, and Cochrane Library (updated to January 2015) for prospective cohort studies. Then, relative risk (RR) with 95% confidence interval (CI) was used to assess the association. Regression analyses, subgroup analyses, and sensitivity analyses were also performed. The Begg test, Egger test, and the trim-and-fill method were used to assess potential publication bias. Results A total of 5707 cases and 926,497 participants in 10 prospective studies were included. Overall, high GGT level has a positive association with increased risk of stroke (RR = 1.28; 95% CI, 1.16-1.43). In the subgroup analyses, a positive association was consistently observed in each subgroup except in the women subgroup (RR = 1.45; 95% CI, .9-2.34) and a large number of stroke events subgroups (≥500) (RR = 1.25; 95% CI, .85-1.84). Heterogeneity was significantly reduced in the subgroup analysis by population characteristics. In the publication bias test, the resulting adjusted RR remained significant (RR = 1.10; 95% CI, 1.00-1.21) after using the trim-and-fill method. Conclusions Our meta-analysis provides evidence that a high level of GGT is significantly associated with increased risk of stroke independently of alcohol intake. Gender and ethnicity variations may exist in the relationship between high GGT level and risk of stroke.

Erythritol (ET) has received increasing research attention for medium-temperature phase change solar-thermal energy storage. However, ET suffers from serious supercooling, low thermal conductivity, poor solar absorption and leakage after melting, which lead to low solar-thermal energy harvesting and releasing efficiency. Herein, we simultaneously overcome these inherent shortcomings by impregnating ET within surface-roughened hydrophilic copper foam, which is prepared by subsequent oxidization of commercial copper foam and thermal reduction under hydrogen, and using stably dispersed crumpled graphene particles as the solar-thermal converter. Such oxidization-reduction-treated copper foam not only provides numerous heterogeneous nucleation sites and lowers the nucleation energy barrier for forming ET crystals during the solidification process, but also facilitates rapid charging and discharging along three-dimensional heat conductive networks, and confines the melted ET. Compared with neat ET, the copper foam-templated composites have reduced the supercooling degree by ~60 °C and improved thermal conductivity by more than 5 times, which in turn lead to a large latent-heat releasing percentage of 85.8% and a high heat-extraction efficiency of 94.2%. We demonstrate that such composites can be used for high-efficiency, medium-temperature, form-stable, direct solar-thermal energy harvesting, and the harvested heat can be readily converted into electricity to power small devices.

Localized heating-based solar distillation has recently emerged as an efficient and facile way to generate freshwater out of saline water. Salt fouling, however, remains a fundamental challenge to stable operation of the desalination system, in particular for high-salinity brine. Here we demonstrate a solar-driven interfacial evaporation-based desalination structure, which achieves localized surface salt precipitation through mediating the horizontal salt concentration gradient within the printed paper-based solar absorber, to minimize salt fouling while maintaining heat localization. With optimized design, such desalination system achieves a stable evaporation efficiency of ~78% under 1100 W m−2 solar illumination, and simultaneously generates drinkable water out of 10 wt% brine with a solar-to-water conversion efficiency more than 40% and NaCl salts with higher productivity over conventional bulk heating-based salt farm technology. This low-cost, environmentally-friendly, bifunctional desalination technology not only helps solve the salt fouling issue but also holds the potential to offer a new way to extract minerals from seawater.