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Carbon materials are widely used in solar-powered seawater desalination (SSD) and have attracted a lot of attention in recent years. Recent developments of carbon-based solar absorbers in SSD are reviewed, including composites of carbon materials with other materials such as metal nanoparticles, semiconductors and biomass materials, their photothermal conversion mechanisms, light utilization efficiencies and salt resistance, and the processes of thermal transport and water transfer. The important roles of carbon in SSD are highlighted, including increasing light absorption, improving photothermal conversion efficiency, and balancing water transfer and salt resistance. The key challenges of carbon-based materials in SSD applications are discussed.

A new type of waterborne epoxy-cement (WEPC) system was developed by adding waterborne epoxy resin (WEP) as an external admixture to cement slurry to solve the problem of cement sheath integrity da...

Long-lasting constant loading commonly exists in silicon-based microelectronic contact, as well as the chemical mechanical polishing area. In this work, the stress relaxation analysis of single crystal silicon coated with an amorphous SiO $$_{2}$$ film is performed by varying the maximum indentation depth using molecular dynamics simulation. It is found that during holding, the applied indentation force declines sharply at the beginning and then steadily towards the end of the holding period. The stress relaxation amount of bilayer composites increases as the maximum indentation depth increases. It is also found that the deformation features of SiO $$_{2}$$ film and silicon substrate during holding are inherited from the loading process. The SiO $$_{2}$$ film during holding is further densified when the maximum indentation depth is equal to or less than a certain value (5.5 nm for the 0.8-nm film). The amount of generated phases and phase distributions of silicon substrate during holding are affected by the plastic deformation of silicon during loading.

Currently, the quantitative analysis methods for uranium that are widely used in laboratories, such as the volumetric method and inductively coupled plasma mass spectrometry (ICP-MS) cannot achieve low cost, simple operation, and little influence by other elements. The inductively coupled plasma optical emission spectrometer (ICP-OES) has a wide linear range, and high stability, and can be used to identify multiple elements simultaneously. However, when ICP-OES is used for quantitative analysis of uranium, the settings for the RF power, nebulizer flow, and pump rate can affect the analysis results. In this work, these parameters were carefully optimized for identifying uranium. Based on experiments, we selected two spectrum peaks 409.014 nm and 424.167 nm for quantitative analysis with the lowest interference. The optimal parameters obtained are atomizer flow rate of 0.75 L/min, a sample pumping rate of 1.6 mL/min, and a high-frequency power of 1400 W. Then we compared the accuracy of the volumetric method, ICP-MS method and ICP-OES method with the optimized parameter for analysis of experimental samples and references. The results showed that the ICP-OES with the optimized parameters proposed in this paper can be used to perform a convenient, quick, and efficient quantitative analysis of uranium in minerals.

After carbon (C) enters a lake through surface runoff and atmospheric deposition, most of it, being influenced by the environmental conditions of the basin, is deposited into lake sediment, thus, becoming one of the most important C pools in the world. Therefore, it is critical to understand sediment response characteristics under the context of increasing C concentrations in lake water. Based on the changes of sediment C concentration at different depths in Poyang Lake, belonging to China's large floodplain-lake system, we revealed the sediment C short-term response characteristics to changes in lake water C concentrations as well as their associated impacting factors. We found that dissolved total carbon (DTC) concentrations increased by 25.78% in winter compared to spring, while total carbon (TC) sediment concentrations increased by only 4.37% during the corresponding period. Specifically, we found that there was a hysteresis effect in the response of sediment C to the increase of water C concentration in the short term. When DTC concentrations in water were below a threshold value (12.50 mg/L), sediment TC concentrations were generally maintained at approximately 5.79 mg/kg. We also believed that biological and environmental factors and sediment stratification characteristics collectively resulted in this sediment C hysteresis effect. Among these factors and characteristics, phytoplankton can affect sediment C response by changing C absorption and utilization in water or cause a synergistic effect along with environmental factors, which is the key link that causes this C sediment hysteresis effect to occur. Furthermore, we found that the combined effect of sediment C from different depths also resulted in a hysteresis effect in C deposition.

The growth of lithium dendrites severely restricts the development of lithium metal batteries. In order to achieve the goal of dendrites-free lithium in principle, it is crucial and urgent to control nucleation and growth of lithium. Here, a functional organic layer of perylene-3, 4, 9, 10-tetracarboxydiimide-lithium (PTCDI-Li) is built on the lithium anode surface by in-situ chemical reaction of PTCDI and Li metal. PTCDI-Li, with high surface energy (-10.19 eV) and low diffusion barrier (0.89 eV), efficiently promotes disk-shaped high-dimensional nucleation by regulation of lithium ion flux upon lithium plating, leading to a dendrites-free morphology. When operating under a relatively high current density of 10 mA cm−2, the Li | Li symmetrical cells with PTCDI-Li exhibit outstanding cyclic stability for 300 hours with ultralow overpotential of 400 mV, superior to the most of the reported lithium anode. The corresponding PTCDI-Li batteries show high specific capacity and enhanced cycle life. We anticipate that this strategy of regulation of lithium deposition from one-dimensional to high-dimensional opens a new horizon in the development of dendrites-free Li anodes.

The movement pattern of ellipsoidal nanoparticles confined between copper surfaces was examined using a theoretical model and molecular dynamics simulation. Initially, we developed a theoretical model of movement patterns for hard ellipsoidal nanoparticles. Subsequently, the simulation indicated that there are critical values for increasing the axial ratio, driving velocity of the contact surface, and lowering normal loads (i.e., 0.83, 15 m/s, and 100 nN under the respective conditions), which in turn change the movement pattern of nanoparticles from sliding to rolling. Based on the comparison between the ratio of arm of force (e/h) and coefficient of friction (μ) the theoretical model was in good agreement with the simulations and accurately predicted the movement pattern of ellipsoidal nanoparticles. The sliding of the ellipsoidal nanoparticles led to severe surface damage. However, rolling separated the contact surfaces and thereby reduced friction and wear.

A marine-sediment-derived bacterium Bacillus velezensis SH-B74 can produce cyclic lipopeptides (CLPs). This study presented the isolation, characterization, and activity evaluation of a new CLP from the bacterial cultures of the strain SH-B74. Multiple chromatographic methods (solid-phase extraction and reversed-phase high-performance liquid chromatography) were applied to the purifying procedure of CLP, and the structural characterization of the new CLP was conducted by various spectroscopy (1D and 2D nuclear magnetic resonance together with Fourier transform infrared spectroscopy) and spectrometry (liquid chromatography-mass spectrometry, high-resolution mass spectrometry and tandem mass spectrometry) techniques as well as Marfey's method. The results displayed that the new CLP (anteiso-C15 Ile2,7 surfactin, 1) consists of a peptidic backbone of L-Glu1, L-Ile2, D-Leu3, L-Val4, L-Asp5, D-Leu6, L-Ile7, and an anteiso-C15 type saturated fatty acid chain. Further activity assay showed that the new CLP displays activity on the inhibition of the appressoria formation of rice blast causal pathogen Magnaporthe oryzae. To sum up, the results presented the perspective of potential application of the new CLP as a green agrichemical to control M. oryzae.

Extracellular adenosine 5′-triphosphate (ATP) is a well-known signalling molecule in plants and plays important roles during plant stress response. In the present work, the treatment of tobacco cell suspension culture with exogenous hydrogen peroxide (H2O2) caused the decreases of respiratory O2 uptake, intracellular ATP production, extracellular ATP level, and reduction of cell viability. Combining this observation with the finding that the oxidative phosphorylation uncoupler or the respiratory inhibitor not only decreased intracellular ATP production but also decreased the extracellular ATP level and cell viability, it is suggested that the decrease of extracellular ATP level and cell viability under H2O2 stress could be a result of the suppressed production of intracellular ATP. Treatment with ATP-degrading enzyme, apyrase, also caused the decreases of cell viability, respiratory O2 uptake, and intracellular ATP production. More importantly, addition of exogenous ATP alleviated the H2O2-induced decreases of cell viability, respiratory O2 uptake, and production of intracellular ATP. These results indicate that extracellular ATP could be an important effector in regulating the cell viability, respiratory O2 uptake, and intracellular ATP production of tobacco cell suspension culture under H2O2 stress.

A uniform bimetallic hollow ZnFe–N/C (80–180 nm) electrocatalyst is synthesized using a precursor ZnFe-ZIF-8 (100–200 nm) subjected to pyrolysis in an argon atmosphere at 800 °C for 2 hours. The ZnFe–N/C catalyst was deposited on a glassy carbon electrode (GCE), and exhibited a superior electrocatalytic activity with a high onset potential (0.97 V vs. RHE) and half-wave potential (0.85 V vs. RHE), high stability in an alkaline electrolyte, and remarkable resistance to methanol. The high performance of the ZnFe–N/C-3 electrocatalyst is attributed to the hollow structure containing metallic Fe/Fe3C and N doping.

In this study, the theory of minimum detectable activity concentration (MDAC) for airborne gamma-ray spectrometry (AGS) was derived, and the relationship between the MDAC and the intrinsic efficiency of a scintillation counter, volume, and energy resolution of scintillation crystals, and flight altitude of an aircraft was investigated. To verify this theory, experimental devices based on NaI and CeBr3 scintillation counters were prepared, and the potassium, uranium, and thorium contents in calibration pads obtained via the stripping ratio method and theory were compared. The MDACs of AGS under different conditions were calculated and analyzed using the proposed theory and the Monte Carlo method. The relative errors found via a comparison of the experimental and theoretical results were less than 4%. The theory of MDAC can guide the work of AGS in probing areas with low radioactivity.

Host-plant-associated bacteria affect the growth, vigor, and nutrient availability of the host plant. However, phyllosphere bacteria have received less research attention and their functions remain elusive, especially in forest ecosystems. In this study, we collected newly developed needles from sapling (age 5 years), juvenile (15 years), mature (25 years), and overmature (35 years) stands of Chinese fir [Cunninghamia lanceolata (Lamb.) Hook]. We analyzed changes in phyllosphere bacterial communities, their functional genes, and metabolic activity among different stand ages. The results showed that phyllosphere bacterial communities changed, both in relative abundance and in composition, with an increase in stand age. Community abundance predominantly changed in the orders Campylobacterales, Pseudonocardiales, Deinococcales, Gemmatimonadales, Betaproteobacteriales, Chthoniobacterales, and Propionibacteriales. Functional predictions indicated the genes of microbial communities for carbon metabolism, nitrogen metabolism, antibiotic biosynthesis, flavonoids biosynthesis, and steroid hormone biosynthesis varied; some bacteria were strongly correlated with some metabolites. A total of 112 differential metabolites, including lipids, benzenoids, and flavonoids, were identified. Trigonelline, proline, leucine, and phenylalanine concentrations increased with stand age. Flavonoids concentrations were higher in sapling stands than in other stands, but the transcript levels of genes associated with flavonoids biosynthesis in the newly developed needles of saplings were lower than those of other stands. The nutritional requirements and competition between individual trees at different growth stages shaped the phyllosphere bacterial community and host–bacteria interaction. Gene expression related to the secondary metabolism of shikimate, mevalonate, terpenoids, tocopherol, phenylpropanoids, phenols, alkaloids, carotenoids, betains, wax, and flavonoids pathways were clearly different in Chinese fir at different ages. This study provides an overview of phyllosphere bacteria, metabolism, and transcriptome in Chinese fir of different stand ages and highlights the value of an integrated approach to understand the molecular mechanisms associated with biosynthesis.

A new cyclic lipopeptide (CLP) orfamide H (1) was purified and identified from the cultural broth of the bacterial strain Pseudomonas protegens CHA0. The crude extract of the strain CHA0 was obtained by an acid-aided precipitation process, then the compound 1 was purified by reversed-phase high-performance liquid chromatography (RP-HPLC). Subsequently, the chemical structure of orfamide H was determined by 1D and 2D nuclear magnetic resonance (NMR) and mass spectrometry (MS). Further biological assays indicate that the new CLP orfamide H shows the activity on inhibiting the appressoria formation of the fungus Magnaporthe oryzae, the causal agent of the blast disease in rice. Taken all together, these results indicated that the new CLP orfamide H has the capacity to be developed as an agrichemical to control blast disease in rice.

Zirconium-toughened-alumina (ZTA) corundum abrasives were successfully fabricated with TiO 2 –SiO 2 co-doping by using the sol-gel method. Single particle compressive strength of the obtained ZTA corundum abrasive was evaluated upon the addition of TiO 2 –SiO 2 in different amounts. The effect of TiO 2 –SiO 2 content on the microstructure of the product was investigated. The X-ray diffraction (XRD) results illustrated that ZrO 2 is present in the α-Al 2 O 3 matrix in the form of t -ZrO 2 . Ti 2 ZrO 6 starts forming when the composition of TiO 2 –SiO 2 is 2 wt% and increases with its addition. The sample doped with 3 wt% TiO 2 –SiO 2 possessed a maximum single particle compressive strength of 45.5 N and a narrow grain size distribution,but excessive TiO 2 –SiO 2 (>3 wt%) causes an abnormal grain growth. The fracture toughness of the composites dramatically increases up to 7.89 Mpa·m 1/2 compared to the monolithic. A crack closure was obviously observed in the ZTA abrasives. The influence of the second phase on its mechanical properties was analyzed.

Composites consisting of cubic boron nitride (cBN) as a matrix and carbon nanotubes (CNTs) as reinforcing additives were fabricated by high-temperature and high-pressure sintering (HTHP). Microstructures, mechanical properties, fracture modes and toughening mechanisms of these composites were investigated. Composites exhibited excellent bending strength, wear resistance, and fracture toughness. Fracture toughness of composites reached 7.02 MPa·m1/2. Comparing to pure cBN matrix, bending strength improved from 475.27 to 600.15 MPa, and wear resistance increased by 43.23%. Such improvements of mechanical properties were mainly attributed to pullout and bridging reinforcements by CNTs. CNTs incorporation also changed fracture mode from inter-to trans-granular.

In this study, we report the synthesis and characterization of cubic boron nitride (cBN)-diamond composites under high-temperature and high-pressure (HTHP) sintering. The effects of diamond content and particle size on phase composition, microstructure, and mechanical properties were investigated. A homogenous microstructure was obtained. Diamond as the second phase positively affected the mechanical properties of cBN composites. With the addition of 1 μm diamond, the highest bending strength and abrasive ratio of cBN composites sintered with 8 wt% diamond were 791 MPa and 2.56, respectively. The hardness of composites sintered with 12 wt% diamond reached up to 60.12 GPa.

In this study, cBN composites incorporating TiN–Al–Co were synthesized via high temperature and high pressure (HPHT) methods. TiB2 nanoparticles were employed to optimize cBN cutting tools capacity for precise cutting. The effects of TiB2 nanoparticles on the preparation and properties of cBN composites were comprehensively investigated. The results show that the presence of TiB2 nanoparticles uniformly distributed in the interface not only promotes the formation of AlCo but also inhibits crack propagation, which contributed to the enhanced mechanical properties. With the appropriate addition of TiB2 nanoparticles, cBN composites obtained the compact and fine microstructure and presented better mechanical properties. Consequently, cBN composites incorporating 6 wt% TiB2 nanoparticles exhibited excellent relative density of 99.81%, bending strength of 731 MPa, hardness of 49.5 GPa, fracture toughness of 7.4 MPa ⋅ m1/2, and abrasive ratio of 2.1. Such composites with outstanding mechanical properties might be promising for cutting tools.

In the present work, treatment with AMP-PCP (β,γ-methyleneadenosine-5'-triphosphate - a competitive inhibitor of the extracellular ATP pool) or apyrase (an ATP-degrading enzyme) decreased the PSII operating efficiency (ΦPSII), photochemical quenching (qp), and maximum quantum efficiency of PSII photochemistry (Fv/Fm) of Arabidopsis leaves illuminated with high light intensity. Mutation of extracellular ATP receptor, DORN1, also caused decreases of ΦPSII, qp, and Fv/Fm when the leaves were exposed to high light. Either the treatment with AMP-PCP and apyrase or the mutation in DORN1 increased the salicylic acid content in the illuminated leaves. Salicylic acid deficiency in NahG transgenic mutant made the PSII photochemistry more sensitive to AMP-PCP or apyrase. These results indicate that extracellular ATP depletion can affect the PSII photochemistry, whereas salicylic acid can relieve this effect.

Rape (Brassica napus L.) seedlings grown in vermiculite-based medium were subjected to short-term copper stress. With the increase of exogenous CuCl2 concentration, photosystem II (PSII) photochemistry and the chlorophyll (Chl) content of rape seedling leaves decreased, while Cu (copper) content of the seedlings, the levels of the soluble protein content, reactive oxygen species (ROS) production, and activities of antioxidant enzymes of the seedling leaves increased. Under the condition without copper stress, there was no significant differences in the measured physiological indexes between the seedlings grown in vermiculite and those grown in the attapulgite clay (AC)/vermiculite mixture with the volume ratio at 1:80, 1:50, or 1:30. After subjected to short-term copper stress, the rape seedlings grown in the mixture of AC/vermiculite had higher levels of Chl content and PSII photochemistry but lower levels of the Cu content, soluble protein content, ROS production, and activities of antioxidant enzymes, compared with the leaves of the seedlings grown in vermiculite. The volume ratio of AC/vermiculite at 1:50 or 1:30 seemed to be the most optimized content in alleviating the physiological effects by the short-term copper stress. These results indicate that AC at moderate content in the growth medium can alleviate the physiological stress of the rape seedlings when excess Cu emerges in the growth medium.

Wounding increased the extracellular Adenosine 5ʹ-triphosphate (eATP) level of kidney bean leaves. Treatment with wounding or exogenous ATP increased the hydrogen peroxide (H2O2) content, activities of catalase and polyphenol oxidase, and malondialdehyde content in both the treated and systemic leaves. Pre-treatment with ATP-degrading enzyme, apyrase, to the wounded leaves reduced the wound-induced local and systemic increases in H2O2 content, activities of catalase and polyphenol oxidase, and malondialdehyde content. Application of dimethylthiourea (DMTU) and diphenylene iodonium (DPI) to the wounded and ATP-treated leaves, respectively, reduced the wound- and ATP-induced local and systemic increases in H2O2 content, activities of catalase and polyphenol oxidase, and malondialdehyde content. Moreover, the wound- and ATP-induced systemic increases of these physiological parameters were suppressed when DMTU or DPI applied to leaf petiole of the wounded and ATP-treated leaves. These results suggest that eATP at wounded sites could mediate the wound-induced local and systemic responses by H2O2-dependent signal transduction. Wounding triggered physiological responses which were related to eATP. eATP initiates a systemic signal, which require the accumulation of H2O2 in local and systemic tissues

Molecular dynamic simulations of nanoindentation were performed to investigate the effects of graphene coatings on the plastic deformation of copper (Cu) under different indentation conditions. The results show that the graphene coating can dramatically strengthen the load bearing capability of Cu substrate for the displacement-controlled indentation, which is proportional to the number of graphene layers increasing from single to triple. And the load force also increases with the rising indentation speed, causing larger and rapider plastic deformation. For the load-controlled indentation, the graphene coating can protect the Cu substrate from being damaged by the external force. The protection capability of graphene increases as the layers growing to triple at the same loading. What's more, the larger load force can facilitate the increase in penetration depth at the equilibrium state. Our observation provide a better understanding of mechanism of plastic deformation under the effect of graphene covering.

One of the main challenges in large-scale applications of molecularly imprinted polymers (MIPs) is the significant amount of template needed in polymer preparation. A new strategy based on room-temperature ionic liquids (RTILs) was suggested to solve this problem by reducing the amount of template in the polymerization recipe. The MIP was synthesized with a mixture of dimethyl sulfoxide and RTIL (1-butyl-3-methylimidazolium tetrafluoroborate) as porogen, in which chlorogenic acid (CGA) was used as template, 4-vinylpyridine (4-VP) as functional monomer, and ethylene glycol dimethacrylate (EDMA) as cross-linker. The influence of polymerization variables, including CGA concentrations, and the ratio of 4-VP to EDMA on imprinting effect were investigated comprehensively. Moreover, the properties involving the column permeability, the number of binding sites, and the polymer morphology of the CGA-MIP monoliths were studied thoroughly. The MIP monolith had an excellent column permeability (1.53 × 10−13 m2) and allowed an ultra-fast on-line SPE, which dramatically shortens the separation time (

With the rapid development of high-speed craft, the novel aluminum alloy stiffened panel with floating girder is widely used to achieve light weight ship hull for economic and high performance. While the mechanical properties of this novel structure are rarely studied. In order to investigate the differences of ultimate strength and collapse behavior between the novel aluminum stiffened panel with floating girder and fixed girder, the uniaxial compression experiments of novel aluminum stiffened panel with floating girder and fixed girder were conducted. Test apparatus were designed to accomplish simply supported boundary condition, then the uniaxial compression experiments were performed, eventually the ultimate strength and collapse behavior of different panels were analyzed. The results of the experiments show that the ultimate strength of novel aluminum stiffened panel with floating girder is higher than the panel with fixed girder under uniaxial compression, which means this type of novel aluminum alloy stiffened panel with floating girder applied on the high-speed craft can improve the ultimate strength of the vessel. Furthermore, it was witnessed that the collapse mode of stiffened panel with fixed girder is tripping of web while that of floating panel is bucking of girder.

Developing new linkage-based covalent organic frameworks (COFs) is one of the major topics in reticular chemistry. Electrically conductive COFs have enabled applications in energy storage and electrochemical catalysis, which are not feasible using insulating COFs. Despite significant advances, the construction of chemically stable conductive COFs by the formation of new linkages remains relatively unexplored and challenging. Here we report the solvent- and catalyst-free synthesis of a two-dimensional aza-bridged bis(phenanthroline) macrocycle-linked COF (ABBPM-COF) from the thermally induced poly-condensation of a tri-topic monomer and ammonia gas. The ABBPM-COF structure was elucidated using multiple techniques, including X-ray diffraction analysis combined with structural simulation, revealing its crystalline nature with an ABC stacking mode. Further experiments demonstrated its excellent chemical stability in acid/base solutions. Electrical-conductivity measurements showed that the insulating ABBPM-COF becomes a semiconducting material after exposure to iodine vapor.

Being a fundamental property of aquatic systems, gross primary productivity (GPP) is affected by complex environmental factors, such as salinity, nutrients, pH, and sunlight. Under conditions of intensified anthropogenic activity and climate change, it is critical to understand the driving mechanisms of GPP in alpine lakes. In this study, we investigated GPP and associated environmental factors of 23 lake systems in the Qinghai–Tibet Plateau (QTP) along an altitudinal range (from 2500 m to 4500 m). Results showed an increase in chlorophyll a (Chl a) content as altitude increased and a corresponding decrease as salinity increased. Furthermore, geographical patterns of GPP were higher at the mid-gradient and lower at the extreme gradient. Higher solar radiation and water temperatures, stronger evaporation and higher salinity levels, and lower pH and higher nutrient content were all driving mechanisms of GPP in low altitudinal lake systems within high latitudinal regions. Such conditions have collectively resulted in the current GPP pattern via the promotion or inhibition of phytoplankton growth and photosynthesis. Specifically, geographical features and climate change jointly drive algal growth and GPP of alpine lake systems via internal circulation processes; however, anthropogenic activities interfere with external circulation processes for most of lower-middle altitudinal lake systems, thus playing a certain role in regulating environmental factors and GPP alongside climate change.

Cellular senescence is associated with pleiotropic essential physiopathological processes including aging and age-related diseases. The persistent DNA damage response (DDR) is a major stress leading to senescence, but the underlying molecular link remains elusive. Here, we identified La Ribonucleoprotein 7 (LARP7), a 7SK RNA binding protein, as a novel aging antagonist. DDR-mediated Ataxia Telangiectasia Mutated (ATM) activation triggered the extracellular shuttling and down regulation of LARP7, which dampened SIRT1 deacetylase activity, enhanced p53 and NF-κB transcriptional activity by augmenting their acetylation, and thereby accelerated cellular senescence. Deletion of LARP7 led to senescent cell accumulation and premature aging in rodent model. Furthermore, we show that this ATM-LARP7-SIRT1-p53/NF-κB senescence axis was active in vascular aging and atherogenesis, and preventing its activation substantially alleviated aging and atherogenesis. Together, this study identifies LARP7 as a gatekeeper for senescence, and the altered ATM-LARP7-SIRT1-p53/NF-κB pathway plays an important role in DDR-mediated cellular senescence and aging-related atherosclerosis.

BackgroundTo explore the changes of chlorophyll content in needles of different leaf ages of Picea koraiensis Nakai of different specifications, the study compared the prediction accuracy changes of chlorophyll in needles of Picea koraiensis Nakai by two modeling methods: the BP neural network and partial least squares regression (PLSR) methods. The effects of different spectral pre-processing and characteristic band selection methods on the performance accuracy of the model were tested, and the optimal combination model was selected to predict forest growth status and community structure productivity through the physiological and biochemical characteristics of needles at different leaf ages. Results1) the spectral pre-processing method could avoid systematic errors and eliminate background values; 2) the accuracy of the needle chlorophyll fitting model with different leaf ages was much higher than that of mixed needle chlorophyll model, verifying that needle chlorophyll with different leaf ages could better estimate the annual growth and examine the growth status of Picea koraiensis Nakai; 3) the accuracy of the BP neural network model was significantly higher than that of the PLSR model, with its R 2 above 0.95, and the validation set’s R 2 above 0.86; and 4) the fitting accuracy of different leaf age needle chlorophyll models of the spectral pre-processing model, variable selection model, PLSR model and BP neural network: triennial needles > annual and biennial needles. ConclusionsThe BP neural network method was more accurate than the PLSR method in predicting pigment content model. In the process of model fitting, it was found that the pigment model fitted by fine classification of needles improves the accuracy of the model, which provides the basis and theoretical support for the establishment of the model by combining remote sensing technology with stoichiometry methods in the future.

The recent pandemic, COVID-19, is caused by a novel coronavirus, SARS-CoV-2, with elusive origin. SARS-CoV-2 infects mammalian cells via ACE2, a transmembrane protein. Therefore, the conservation and expression patterns of ACE2 may provide valuable insights into tracing the carriers of SARS-CoV-2. In this work, we analyzed the conservation of ACE2 and its expression pattern among various mammalian species that are close to human beings. We show that mammalian ACE2 gene is deeply conserved at both DNA and peptide levels, suggesting that a broad range of mammals can potentially host SARS-CoV-2. We further report that ACE2 expression in certain human tissues are consistent with clinical symptoms of COVID-19 patients. Furthermore, we have built the first atlas of ACE2 expression in various common mammals, which shows that ACE2 expresses in mammalian tissues in a species-specific manner. Most notably, we observe exceptionally high expression of ACE2 in external body parts of cats and dogs, suggesting that these household pet animals could be vulnerable to viral infections and/or may serve as intermediate hosts, thus yielding novel insights into the transmission of SARS-CoV-2., COVID-19; 2019-nCov; Novel coronavirus; Potential host; Susceptibility.

The endothelial-to-mesenchymal transition (EndMT) is a critical process that occurs during the development of the outflow tract (OFT). Malformations of the OFT can lead to the occurrence of conotruncal defect (CTD). SOX7 duplication has been reported in patients with congenital CTD, but its specific role in OFT development remains poorly understood. To decipher this, histological analysis showed that SRY-related HMG-box 7 (SOX7) was regionally expressed in the endocardial endothelial cells and in the mesenchymal cells of the OFT, where EndMT occurs. Experiments, using in vitro collagen gel culture system, revealed that SOX7 was a negative regulator of EndMT that inhibited endocardial cell (EC) migration and resulted in decreased number of mesenchymal cells. Forced expression of SOX7 in endothelial cells blocked further migration and improved the expression of the adhesion protein vascular endothelial (VE)-cadherin (VE-cadherin). Moreover, a VE-cadherin knockdown could partly reverse the SOX7-mediated repression of cell migration. Luciferase and electrophoretic mobility shift assay (EMSA) demonstrated that SOX7 up-regulated VE-cadherin by directly binding to the gene’s promoter in endothelial cells. The coding exons and splicing regions of the SOX7 gene were also scanned in the 536 sporadic CTD patients and in 300 unaffected controls, which revealed four heterozygous SOX7 mutations. Luciferase assays revealed that two SOX7 variants weakened the transactivation of the VE-cadherin promoter. In conclusion, SOX7 inhibited EndMT during OFT development by directly up-regulating the endothelial-specific adhesion molecule VE-cadherin. SOX7 mutations can lead to impaired EndMT by regulating VE-cadherin, which may give rise to the molecular mechanisms associated with SOX7 in CTD pathogenesis.

Uniaxial tension tests were performed for amorphous SiO2 nanowires using molecular dynamics simulation to probe the size effect on the mechanical properties and plastic deformation by varying the length of nanowires. The simulation results showed that the Young&rsquo, s modulus of SiO2 nanowires increased with the decrease of nanowires length due to its higher surface stress. The corresponding deformation of SiO2 nanowires during tension exhibited two periods: atomic arrangement at small strain and plastic deformation at large strain. During the atomic arrangement period, the percentage variations of atom number of 2-coordinated silicon and 3-coordinated silicon (PCN2 and PCN3) decreased, while the percentage variations of atom number of 4-coordinated silicon, 5-coordinated silicon (PCN4 and PCN5) and the Si&ndash, O bond number (PCB) rose slightly with increasing strain, as the strain was less than 22%. The situation reversed at the plastic deformation period, owing to the numerous breakage of Si&ndash, O bonds as the strain grew beyond 22%. The size effect of nanowires radius was considered, finding that the Young&rsquo, s modulus and fracture stress were higher for the larger nanowire because of fewer dangling bonds and coordinate defeats in the surface area. The elastic deformation occurred at a small strain for the larger nanowire, followed by the massive plastic deformation during tension. A brittle mechanism covers the fracture characteristics, irrespective of the nanowire size.

Angiogenesis, the formation of new blood vessels from pre-existing ones, is vital for vertebrate development and adult homeostasis. Acid α-glucosidase (GAA) is a glycoside hydrolase involved in the lysosomal breakdown of glycogen. Our previous study showed that GAA was highly expressed in mouse pulmonary veins. While whether GAA was involved in angiogenesis remained largely unknown, thus, we performed knockdown experiments both in vivo and in vitro and endothelial cell function experiments to clarify this concern point. We identified that GAA expressed widely at different levels during zebrafish embryonic development and GAA morphants showed excessive angiogenesis of ISV at later stage. In GAA knockdown HUVECs, the migration and tube formation capacity were increased, resulted from the formation of large lamellipodia-like protrusions at the edge of cells. By analyzing autophagic flux, we found that autophagy disorder was the mechanism of GAA knockdown-induced excessive angiogenesis. The block of autophagic flux caused upregulation of Rac1, a small GTPase, and the latter promoted excessive sprouts in zebrafish and enhanced angiogenic behavior in HUVECs. In addition, overexpression of transcription factor E3, a master regulator of autophagy, rescued upregulation of RAC1 and enhanced angiogenic function in GAA-knockdown HUVECs. Also, inhibition of Rac1 partly restored enhanced angiogenic function in GAA-knockdown HUVECs. Taken together, our study firstly reported a novel function of GAA in angiogenesis which is mediated by upregulation of Rac1 induced by autophagy disorder.

Isorhamnetin (ISO), a naturally occurring plant flavonoid, is widely used as a phytomedicine. The major treatment modality for non-small-cell lung carcinoma (NSCLC) is radiotherapy. However, radiotherapy can induce radioresistance in cancer cells, thereby resulting in a poor response rate. Our results demonstrated that pretreatment with ISO induced radiosensitizing effect in A549 cells using colony formation, micronucleus, and γH2AX foci assays. In addition, ISO pretreatment significantly enhanced the radiation-induced incidence of apoptosis, the collapse of mitochondrial membrane potential, and the expressions of proteins associated with cellular apoptosis and suppressed the upregulation of NF-κBp65 induced by irradiation in A549 cells. Interestingly, the expression of interleukin-13 (IL-13), an anti-inflammatory cytokine, was positively correlated with the ISO-mediated radiosensitization of A549 cells. The knockdown of IL-13 expression by RNA interference decreased the IL-13 level and thus reduced ISO-mediated radiosensitivity in cells. We also found that the IR-induced NF-κB signaling activation was inhibited by ISO pretreatment, and it was abrogated in IL-13 silenced cells. We speculated that ISO may confer radiosensitivity on A549 cells via increasing the expression of IL-13 and inhibiting the activation of NF-κB. To our knowledge, this is the first report demonstrating the effects of ISO treatment on the responsiveness of lung cancer cells to irradiation through IL-13 and the NF-κB signaling pathway. In summary, ISO is a naturally occurring radiosensitizer with a potential application in adjuvant radiotherapy.

Purpose Resolvin is a checkpoint controller in inflammation. Matrix metalloproteinase-9 (MMP-9) is an airway remodeling regulator. We evaluated the levels of resolvin and MMP-9 protein in the serum and exhaled breath condensate (EBC) before and after continuous positive airway pressure (CPAP) treatment. Method We enrolled 20 non-OSA snorers and 40 patients with moderate to severe OSA scheduled for CPAP treatment. ELISA was used to assess resolvin and MMP-9 levels in the serum and EBC. All patients underwent sleep assessment at baseline and 3 months after CPAP. Results There was no between-group difference; moreover, there were no differences in the pre- and post-treatment serum levels of resolvin and MMP-9 in patients with OSA. Compared with non-OSA snorers, patients with OSA had lower resolvin and higher MMP-9 levels in the EBC. After CPAP treatment, the EBC levels of resolvin and MMP-9 in patients with OSA returned to normal. Conclusions Successful OSA treatment by CPAP can normalize EBC levels of resolvin and MMP-9.

The heart is the first organ to form during embryogenesis and its development is a complex process. In this study, we identified 120 ligand-receptor pairs including 65 ligands and 58 receptors specifically expressed in one of the nine cell types. The correlation analysis of the cell proportions revealed that the cell-to-cell contact exhibited spatial patterns in human fetal heart. Specifically, the cardiomyocytes (CMs) proportion might have negative correlation with proportion of endothelial cell in left atrium and ventricle during the heart development. In contrast, fibroblast-like cells and macrophages were jointly increased with the gestation. Furthermore, the ligand in CM, NPPA (Natriuretic Peptide A), and receptor in endothelial cell (EC), NPR3 (Natriuretic Peptide Receptor 3), were specifically expressed in atrial CM and endocardial cells, respectively, indicating that the atrial CM might communicate with endocardial cells via NPPA-NRP3 interaction. Moreover, the interplay between fibroblast-like cell and macrophage was observed in both left and right atriums via the ligand-receptor interactions of COL1A1/COL1A2 (Collagen Type I Alpha 1/2 Chain)-CD36 and CTGF (connective tissue growth factor)-ITGB2 (Integrin Subunit Beta 2). Functional enrichment analysis revealed that the ligand-receptor interactions might be associated with the intracellular activation of cGMP-PKG signaling pathway in ECs, PDGF-beta signaling pathway in fibroblast-like cell, and Toll-like receptor signaling in macrophage, respectively. Collectively, the present study unveiled the potential cell-cell communication and underlying mechanism involved in cardiac development, which broadened our insights into developmental biology of heart.

BackgroundCOVID-19 has become a worldwide pandemic. It is caused by a novel coronavirus named SARS-CoV-2 with elusive origin. SARS-CoV-2 infects mammalian cells by binding to ACE2, a transmembrane protein. Therefore, the conservation of ACE2 and its expression pattern across mammalian species, which are yet to be comprehensively investigated, may provide valuable insights into tracing potential hosts of SARS-CoV-2.MethodsWe analyzed gene conservation of ACE2 across mammals and collected more than 140 transcriptome datasets from human and common mammalian species, including presumed hosts of SARS-CoV-2 and other animals in close contact with humans. In order to enable comparisons across species and tissues, we used a unified pipeline to quantify and normalize ACE2 expression levels.ResultsWe first found high conservation of ACE2 genes among common mammals at both DNA and peptide levels, suggesting that a broad range of mammalian species can potentially be the hosts of SARS-CoV-2. Next, we showed that high level of ACE2 expression in certain human tissues is consistent with clinical symptoms of COVID-19 patients. Furthermore, we observed that ACE2 expressed in a species-specific manner in the mammals examined. Notably, high expression in skin and eyes in cat and dog suggested that these animals may play roles in transmitting SARS-CoV-2 to humans.ConclusionsThrough building the first atlas of ACE2 expression in pets and livestock, we identified species and tissues susceptible to SARS-CoV-2 infection, yielding novel insights into the viral transmission.

The presence of cell-free tumor-derived DNA (ctDNA) in plasma of cancer patients was first reported 30 years ago (1), which opens the door of blood-based analysis for cancer diagnosis and monitoring, or so-called cancer liquid biopsy. In recent years, with the development of high- throughput and high sensitive techniques, cancer liquid biopsy has gained much interest and is actively researched globally (2). As a genetic disease, one hallmark of cancer is acquired somatic mutations in the genome of tumor cells, which could be detected in plasma ctDNA. A variety of assays had been developed to screen and quantify the tumor-derived somatic mutations in plasma. For instance, assays that utilized high depth sequencing technology, either on the whole human genome or specific regions of interest using target capture approaches, had showed good sensitivity and accuracy in this task (3,4). However, parallel analysis of plasma DNA and matched tumor tissues had revealed that in cancer patients of various types, even though the somatic mutation profiles of these two materials showed remarkable concordance, they were not identical (4-6). Conventionally, the intratumor heterogeneity is proposed to be the major reason to this phenomenon (2,7). However, the tissue origin of the mysterious somatic mutations that are only found in the plasma still remains elusive.

The bivalent domain (BD) at promoter region is an unique epigenetic feature poised for activation or repression during cell differentiation in embryonic stem cell. However, the function of BDs in already differentiated cells remains exclusive. By profiling the epigenetic landscape of endothelial cells during VEGFA (vascular endothelial growth factor A) stimulation, we discovered that BDs are widespread in endothelial cells and preferentially marked genes responsive to VEGFA. The BDs responsive to VEGFA have more permissive chromatin environment comparing to other BDs. The initial activation of bivalent genes depends on RNAPII pausing release induced by EZH1 rather than removal of H3K27me3. The later suppression of bivalent gene expression depended on KDM5A recruitment by its interaction with PRC2. Importantly, EZH1 promoted both in vitro and in vivo angiogenesis by upregulating EGR3, whereas KDM5A dampened angiogenesis. Collectively, this study demonstrates a novel dual function of BDs in endothelial cells to control VEGF responsiveness and angiogenesis.

Neurodegenerative diseases (NDDs) are becoming a major threat to public health, according to the World Health Organization (WHO). The most common form of NDDs is Alzheimer’s disease (AD), boasting 60-70% share. Although some debates still exist, excessive aggregation of β-amyloid protein (Aβ) and neurofibrillary tangles has been deemed one of the major causes for the pathogenesis of AD. A growing number of evidences from studies, however, have suggested that reactive oxygen species (ROS) also play a key role in the onset and progression of AD. Although scientists have had some understanding of the pathogenesis of AD, the disease still cannot be cured, with existing treatment only capable of providing a temporary relief at best, partly due to the obstacle of blood-brain barrier (BBB). The study was aimed to ascertain the neuroprotective effect of thermal cycle hyperthermia (TC-HT) against hydrogen peroxide (H2O2) and Aβ-induced cytotoxicity in SH-SY5Y cells. Treating cells with this physical stimulation beforehand significantly improved the cell viability and decreased the ROS content. The underlying mechanisms may be due to the activation of Akt pathway and the downstream antioxidant and prosurvival proteins. The findings manifest significant potential of TC-HT in neuroprotection, via inhibition of oxidative stress and cell apoptosis. It is believed that coupled with the use of drugs or natural compounds, this methodology can be even more effective in treating NDDs.

Membrane technology is believed as a cost-effective approach for solving the water issues, where as it suffers from serious membrane fouling. Surface grafting and surface coating have been proved to be effective in abating the membrane fouling; however, these processes always need additional procedures and compromise the initial permeance of the membranes. Herein, we developed a kind of highly permeable polyacrylonitrile (PAN) membranes with excellent anti-fouling performance through one-step phase inversion of the PAN casting solution containing water-soluble active additives. During the process, the water-soluble active additives could segregate towards the membrane surface and pore walls; thereby finely tailoring the pore structures of the PAN-based membranes. Moreover, the active additives could react with each other to form crosslinked networks containing multi-hydrophilic functional groups including CH2–O–CH2, –OH or -Si-OH. Consequently, the PAN-based membranes exhibited surprising superhydrophilicity with water contact angle below 10° even after soaking in water for one week and the anti-fouling permeance of the membranes increased significantly with permeance recovery rate above 93%. Interestingly, the modified membranes also demonstrated both high permeances and high separation efficiency, thereby showing strong promise in water environmental remediation including wastewater treatment and oil/water emulsion separation.

Inspired by the architectural feature of the natural enzyme of carbon monoxide dehydrogenase, cysteamine-capped Au nanoparticles (CA–Au NPs) are investigated with remarkable mass activity for CO2 r...

To explore the effect of indentation speed on the deformation behaviors of silicon (Si) surface coated with silica (SiO 2 ) in chemical mechanical polishing process, the nanoindentation test is performed by molecular dynamics (MD) simulation. It is found that the force and indentation depth at which the force drops for high speed are lower than those for low speed, implying the mechanical strength of the bilayer composite increasing with a reducing indention speed. The percentage variations of atom number of coordinated silicon and Si-O bond number consistently indicate that the SiO 2 film at higher speed tends to fracture preferentially without sufficient densification and the amount of deformation is also larger. As amorphous SiO 2 film tends to fracture during indentation, the original Si-I and newly generated Si-II phases induced by indentation within underlying silicon begin to transform to a Si amorphous structure, which reveals the reason for why the CN5 number for higher indentation speed are larger than those for lower speed at the same indentation depth but with lower CN6 number when indentation depth grows from 4.0 nm to 8.2 nm. Stress analysis indicates the much higher shear stress subjected to silicon at higher speed facilitates the crystalline-to-amorphous transformation.

Radiation damage in reactor materials caused by the collision of the fast neutrons has a great impact on the reliability and safety of nuclear reactors. The element vanadium has attracted interest ...

The mechanical properties and deformation behaviors of monocrystalline silicon coated by an amorphous SiO2 film with different thicknesses are explored by nanoindentation process with molecular dynamics (MD) simulation. The results indicate that the calculated indentation modulus increases with the growing indentation depth for monocrystalline silicon with and without amorphous SiO2 film, while the modulus decreases with increasing film thickness at the same indentation depth. The derived hardness during indentation process, which is more sensitive to amorphous SiO2 film thickness, is complex due to the plastic deformation of SiO2 film, illustrating a deformation-induced softening behavior. The plastic deformation of amorphous SiO2 film exhibits four periods during whole indentation process, namely densification, densification–rupture transition, rupture during loading and elastic recovery during unloading, which are reasonably verified by CN number of silicon atoms and Si–O bond number within SiO2 film as a function of indentation depth. It is concluded that the SiO2 film acts as a medium to dissipate the energy and to transmit the stress from indenter to underlying silicon substrate. The MD results show that the differences of phase distribution between silicon with and without SiO2 film at the same penetration depth are driven by the stress.