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To investigate the combustion characteristics of multiple fire sources in the tunnel caused by 'jumping' discontinuous fire spread, we utilized scaled model experiments, numerical simulation software, and theoretical research. Our study focused on analyzing the influence of different fire source powers on the temperature characteristics of double fire sources in the tunnel. We examined the temperature characteristics, critical wind speed, and change rule under various wind speeds, fire source spacing, and fire source powers. Additionally, we explored the temperature characteristics, critical wind speed, and change rule of different fire source powers under varying wind speed conditions. The mathematical model for roof temperature decay and the temperature decay coefficients of dual source fires were established through the analysis of scale-down model experiments and numerical simulations. In comparison to single-source fires, the temperature variations in the tunnel of dual source fires exhibit a more intricate pattern, with higher average temperature and temperature peak values. These values are influenced by factors such as fire source spacing and power. Numerical simulation software was utilized to investigate the impact of fire source spacing at 10 m, 15 m, and 20 m, as well as the effect of varying fire source power on the temperature distribution within a tunnel under consistent fire source position and growth coefficient. The study revealed that, with consistent double fire source position and ventilation conditions in the tunnel, the upstream fire source exhibited greater power than the downstream fire source, resulting in the lowest average and peak temperatures in the tunnel. This observation could potentially enhance escape and rescue operations within the tunnel. Similarly, the lowest average and peak temperatures in the tunnel were also identified, offering potential benefits for optimizing escape and rescue strategies in tunnel scenarios. [ABSTRACT FROM AUTHOR]

Fog processing has a significant impact on sulfur chemistry in the atmosphere. This study analyzed three winter fog events in Hong Kong using single‐particle aerosol mass spectrometry (SPAMS) and a Monitor for AeRosols and GAses in ambient air (MARGA). Black carbon (BC)‐related carbonaceous particles with substantial sulfate amounts comprised the largest particle number fraction (56.7%). Sulfate mass concentration decreased during fog due to the cloud's effective scavenging, but fog processing notably promoted sulfate formation at the single‐particle level (average peak area increases of 31.2%). Hydroxymethanesulfonate (HMS), an important S(IV) compound and fog tracer, was identified accounting for up to 12% by particle number fraction. Although pH showed a positive correlation (r = 0.53–0.69) with HMS particles in each fog scenario, a negative overall correlation (r = −0.51) was observed. Further analysis revealed that the higher aerosol acidity (pH 0.65–3.11), promoted Fe dissolution, leading to 49% of HMS particles being mixed with Fe, which potentially facilitated sulfate formation via the Fenton reaction. Additionally, around 40% of HMS‐Fe particles are mixed with oxalate, thereby warranting further attention for their potential to cause more intricate sulfur oxidation processes. This study reveals the initial identification of a high mixed‐state of HMS‐Fe, which could potentially serve as a crucial avenue for the formation of sulfate on individual particulate matter. Considering the persistent augmentation of aerosol acidity in the Asian region, this phenomenon necessitates further investigation and attention. Plain Language Summary: Cloud and fog processes are crucial for atmospheric chemistry and important pathways in sulfate formation. However, current models often underestimate sulfate production in the atmosphere. While several potential pathways have been proposed, the influence of organic compounds on hydroxymethanesulfonate (HMS) formation and its subsequent sulfate generation is yet to be fully explored. This study, utilizing a single‐particle perspective, reveals that higher aerosol acidity in coastal areas can lead to the dissolution of iron (Fe) in coastal aerosols, thereby promoting the formation of HMS‐Fe. Additionally, as a transition metal, Fe has the potential to catalyze the conversion of HMS to sulfates. This finding challenges the prevailing notion that HMS hinders sulfate production by being less susceptible to oxidation by hydrogen peroxide (H2O2) and other radicals. The significance of this process is particularly pronounced in coastal or remote marine atmospheres, where cloud and fog processes exhibit higher aerosol acidity and limited ammonia sources. Furthermore, considering the current global scenario of increased aerosol acidity, the impact of transition metals on sulfate formation in HMS is likely to be more prominent. Consequently, this phenomenon necessitates further investigation and attention. [ABSTRACT FROM AUTHOR]

Dust aerosols serve as a crucial nutrient source to the oceans and profoundly influence marine ecosystems. This study used satellite and ground observations to explore a strong dust event on 9–13 April 2023, emanating from the Gobi Desert, shared by Mongolia and China's Inner Mongolia region. We investigated the deposition of dust particles and their effects on marine phytoplankton communities. Our findings revealed that the dust event was intense, enduring, and expansive, illustrated by hourly PM10 concentrations peaking at 5055 µg/m3 near the source and consistently exceeding 1000 µg/m3, even at considerable distances. The dust traveled along two different trajectories and was deposited in the same area of the Northwest Pacific. Total dust deposition in the study area (37°N–42°N, 145°E–165°E) was 79.88 mg/m2 from 13 to 18 April, much higher than the 2019–2022 average deposition of 33.03 mg/m2 for the same period. With dust deposition, the observed mean chlorophyll-a concentrations in the area increased to 2.78 mg/m3 on 14 April, an extraordinary 692% increase above the long-term average. These results highlight the profound impact of dust on the productivity of marine phytoplankton communities by inputting more nutrients into the ocean through different pathways. [ABSTRACT FROM AUTHOR]

To investigate resistance change in the fire area of a roadway caused by roadway fires, a mathematical calculation model for thermal resistance is developed. Theoretical research is conducted to analyze the factors influencing resistance change through theoretical derivation, revealing that temperature is a key factor contributing to the change in thermal resistance. By leveraging the correlation between changes in CO concentration and temperature on the downwind side of the roadway within the fire zone, researchers developed mathematical models to predict temperature increases at various points downwind of the fire source. These models were then used to determine the mathematical relationship governing the change in thermal resistance. The accuracy of the numerical simulation software was validated using Fluent numerical simulation software and scaled-down model experiments. Full-scale numerical simulation experiments were conducted to investigate the fire characteristics of roadway fires and validate the thermal resistance mathematical model. The results indicate that the thermal resistance in the numerical simulation is 7.55 Pa at 20m from the fire source and 5.54 Pa at the end of the roadway. The decrease in resistance is linear. The minimum error between the thermal resistance calculated by the mathematical model and the gradient of the pressure drop in the numerical simulation is 0.03 Pa, approximately 2.3%. Furthermore, the fitting degree of the pressure drop in each section is as high as 97.7%. The calculation model demonstrates high accuracy and offers a theoretical foundation for investigating fire resistance in tunnel fire. [ABSTRACT FROM AUTHOR]

Photocatalytic reactions during the daytime, alongside aqueous-phase reactions occurring during both daytime and nighttime, are identified as the two primary processes facilitating the conversion of aerosol iron (Fe) from the insoluble state to the soluble state within the atmospheric environment. This study investigated the levels of total Fe (Fe T) and soluble Fe (Fe S) in PM 2.5 samples collected during daytime and nighttime in Qingdao, a coastal city in eastern China, evaluating the distinctive roles of these two pathways in enhancing aerosol Fe solubility (%Fe S , defined as the ratio of Fe S to Fe T). Under clean and humid conditions, characterized by prevailing sea breezes and a relative humidity (RH) typically above 80 %, an average daytime %Fe S of 8.7 % was observed, which systematically exceeded the nighttime %Fe S (6.3 %). Photochemical conversions involving oxalate contributed to the higher %Fe S observed during daytime. Conversely, in scenarios where air masses originated from inland areas and exhibited slightly polluted, daytime %Fe S (3.7 %) was noted to be lower than the nighttime %Fe S (5.8 %). This discrepancy was attributable to the variations in RH, with nighttime RH averaging around 77 %, conducive to the more efficient generation of acidic compounds, thereby accelerating Fe S production compared to the daytime, when RH was only about 62 %. Furthermore, the oxidation rates of sulfur (SOR) displayed a strong correlation with RH, particularly when RH fell below 75 %. A 10 % increase in RH corresponded to a 7.6 % rise in SOR, which served as the primary driver of the higher aerosol acidity and %Fe S at night. These findings highlight the RH-dependent activation of aqueous-phase reactions and the augmentation of daytime photocatalysis in the formation of Fe S in the coastal moist atmosphere. [ABSTRACT FROM AUTHOR]

Smoke aerosols from wildfires play a vital role in marine ecosystems and the ocean carbon cycle. This study analyzed a severe wildfires incident occurred in the Indo‐China Peninsula on 26 March 2019, and assessed its impact on ocean carbon sink. The satellite observations showed that the wildfires covered an area of about 56% of the entire peninsula, burning an area of 1.17 × 106 km2. Consequently, the wildfires discharged about 0.43 × 109 kg carbon. Moreover, a substantial amount of smoke released by severe wildfires was carried downstream by the wind and reached the western Pacific Ocean within 2 days. These smoke aerosols contribute to the ocean carbon sink through the mechanisms of the biological pump and their own carbon deposition. Model simulation results showed smoke aerosols contribute 6.44 × 104 kg black carbon to surface ocean by their own carbon deposition. Moreover, during the period of smoke aerosol's deposition, the flourishing growth of phytoplankton resulted in an increased carbon export of 0.25 ± 0.09 × 109 kg carbon (the biological pump mechanism), which represented approximately 57.97% ± 20.30% of the carbon emissions originating from the wildfire‐affected source region. Our research showed a positive impact of large wildfires on the ocean carbon sink, indicating the potential of smoke aerosols to alleviate the climate pressures resulting from carbon dioxide released by wildfires through improving the capacity of ocean carbon sink. Plain Language Summary: Wildfires emit substantial amounts of carbon dioxide into the atmosphere within a short timeframe. The ocean can mitigate the environmental impact of these wildfire events by fixing carbon. As one of the world's fire hotspot and the most significant burning area in the whole of Asia, it is necessary to understand the contribution of smoke aerosols emitted from the Indo‐China Peninsula to the Pacific Ocean carbon sink. We found that the source area of wildfires emitted 0.43 × 109 kg of carbon on 26 March 2019, and the smoke aerosols emitted by wildfires were carried by winds to the western Pacific Ocean within two days, and inputted 6.44 × 104 kg of black carbon. The increased ocean carbon export during the deposition of the smoke aerosol was 0.25 ± 0.09 × 109 kg, which is about half of the carbon emissions caused by wildfires. The results of this study suggest that smoke aerosols can contribute to the oceanic carbon sink, thereby alleviating the pressure on carbon emissions caused by wildfires. Key Points: A severe fire incident which account for 56% of the land area of the Indo‐China Peninsula has been researchedContribution of smoke aerosols to surface ocean carbon sink is primarily attributed by biological pump rather than carbon self‐depositionThe ocean assimilates around 57.97% ± 20.30% of the carbon emissions released by wildfires [ABSTRACT FROM AUTHOR]

The Paleo-Asian Ocean (PAO) had multiple collage systems and closed along multiple sutures. The final timing of the closure of the PAO was closely related to the formation of Pangea. The final timing of closure of the eastern PAO is controversial and may have been from the Middle Permian to the Middle Triassic. This paper presents new zircon U–Pb ages and Hf isotope data for sedimentary and volcanic rocks layer in the Linxi Formation in the Xingmeng Orogenic Belt (XMOB). We also obtained geochemical data for the volcanic rocks layer to constrain the timing and mechanisms of the PAO closure. Detrital zircon U–Pb dating yielded the youngest ages peak of ca. 263 and 260 Ma for two sandstone samples. Combined with the crystallization age of the volcanic rocks layer (254.2 ± 1.3 Ma), this indicates the Linxi Formation was deposited during the Late Permian. Age spectra and Hf isotopic compositions of the detrital zircons from the Linxi Formation suggest that detrital zircons with ages of <1500 Ma were derived from the XMOB, whereas those with ages of 2100–1600 Ma were derived from both the XMOB and the North China Craton (NCC). The detrital zircons with ages of >2400 Ma were derived from the NCC. Geochemical features of the volcanic rocks layer are consistent with eruption in a compressional tectonic setting and derivation by partial melting of the lower crust. Based on our data and the Late Permian history of magmatism and sedimentation, the Linxi Formation was likely deposited in a tectonic setting that transitioned from convergence to collision. Finally, we suggest the PAO closed in a ‘scissor-like’ fashion in the eastern CAOB during the Late Permian, in a setting of tectonic compression. [ABSTRACT FROM AUTHOR]

Polar stratospheric clouds (PSCs) play a key role in Arctic amplification and stratospheric ozone destruction in polar regions. In this paper, we used the CALIPSO data to analyze the spatiotemporal distribution of Arctic PSCs from 2006 to 2021. We found that Arctic PSCs mainly appear in December, peak in late December and early January, disappearing in late February and early March. PSCs can extend from heights near the tropopause to over 25 km. However, there is the lowest fraction of PSCs in the 2014/2015 winter. This study found that the temperature in the 2014/2015 winter was warmer than the 15‐year average temperature, with the lowest temperature slightly below the PSCs formation temperature of about 5 K. The formation of the Ural blocking high accompanied by the poleward propagation of the planetary wave caused a sudden stratospheric warming (SSW) event on 3 January 2015, during which the warm air entered the polar vortex and divided it into two lobes. Additionally, a reduction in SO2 column mass density before the SSW event resulted PSCs occurring with a frequency of only 0.148 and dissipating rapidly in December. Moreover, the concentration of H2O and HNO3 in the gravitational settling process of PSCs decreased by 20–50%, the reduction of condensation nuclei made PSCs with the highest frequency of 0.074 in February appear briefly and then disappear. The chemical and dynamic analysis of PSCs formation is needed to further understand the spatiotemporal distribution of Arctic PSCs and to better predict future Arctic amplification and ozone destruction. Plain Language Summary: Polar stratospheric clouds (PSCs) influence polar ozone depletion by providing a reaction interface and also influencing surface temperature changes through longwave radiation effects. Previous studies on polar stratospheric clouds mainly focus on the Antarctic, and few studies on the temporal and spatial distribution characteristics of Arctic PSCs over long timescales. Therefore, by studying the spatial and temporal distribution of PSCs in the Arctic, we found that the spatial and temporal distribution of PSCs in the Arctic has obvious interannual variation compared with that in the Antarctic. The stratospheric sudden warming (SSW) events that occur almost every 2 years in the Arctic cause great interannual variations of the Arctic polar vortex and thus affect the distribution of Arctic PSCs. Moreover, there is the least and almost none occurrence of PSCs in the 2014/2015 winter, the chemical and dynamic analysis found that SSW, decrease of SO2, H2O, and HNO3 concentration are not conducive to the formation of PSCs. It is of great significance to study the influencing factors of Arctic PSCs formation and provide a new basis for further prediction of Arctic amplification and ozone destruction. Key Points: The fraction of Arctic polar stratospheric clouds (PSCs) during 2014/2015 winter was the lowest observed in the past 15 yearsThe splitting of polar vortex and the rise in temperature caused by sudden stratospheric warming (SSW) inhibited the formation of PSCsThe decrease in stratospheric sulfur dioxide, nitric acid, and water was unfavorable for the formation of PSCs before and after the SSW [ABSTRACT FROM AUTHOR]

Photocatalysis reactions occurring during daytime and aqueous-phase reactions during both daytime and nighttime constitute the two primary processes responsible for converting aerosol iron (Fe) from insoluble to soluble forms within the atmosphere. This study investigated the composition of total Fe (FeT) and soluble Fe (FeS) in daytime and nighttime PM2.5 in Qingdao, a coastal city in eastern China, and evaluated the distinctive roles of the two pathways in enhancing the solubility of aerosol Fe (%FeS, the ratio of FeS to FeT). In clean and humid conditions characterized by sea breezes, with relative humidity (RH) prevalently exceeding 80 %, an average daytime %FeS of 8.7 % was observed, which systematically surpassed its nighttime %FeS (6.3 %). In contrast, when the air originated from land regions and was slightly polluted, the daytime %FeS (3.7 %) was noted to be lower than the nighttime %FeS (5.8 %). This discrepancy was attributable to the variations in RH, as the nighttime RH approximated to be 77 %, facilitating the more efficient formation of acidic substances and resulting in faster FeS production than during daytime, when RH was about 62 %. Furthermore, the oxidation rates of sulfur (SOR) and nitrogen (NOR) displayed strong correlations with RH, particularly when RH was below 75 %. A 10 % increase in RH resulted in a 7.6 % increase in SOR and a 7.2 % elevation in NOR, which served as the primary reason for the differences in aerosol acidity and %FeS between daytime and nighttime. These findings highlight the RH-dependent activation of aqueous-phase reactions and the augmentation of daytime photocatalysis in the formation of FeS in the coastal moisture atmosphere. [ABSTRACT FROM AUTHOR]

To determine the effect of water contents on the oxidation spontaneous combustion of coal gangue, the properties and combustion characteristics of coal gangue were studied using industrial and elemental analyses and Thermo Gravimetry-Differential Scanning Calorimetry (TG-DSC). The molecular dynamics simulation (MDS) and giant regular Monte Carlo simulation (GCMC)were used to investigate the adsorption isotherms of oxygen and coal gangue (kaolinite) under different water molecules (400, 500, 600, 700). The results of thermogravimetric showed that with increasing moisture content, the characteristic temperature points T3-T5 of CG4 were much lower than those of the other samples, the combustion conversion rate is the highest and the spontaneous combustion effect is the best at the same temperature. The molecular simulation results show that under 700 water-oxygen system, the adsorption of oxygen molecules and kaolinite (001) surface is the strongest. The interface has the fewest water molecules and the largest diffusion coefficient. [ABSTRACT FROM AUTHOR]

Transition metal nitrides (TMNs) are promising electrode materials for high-performance energy storage devices owing to their excellent conductivity, thermal stability, high theoretical capacity and excellent electrochemical activity. However, the structural instability present in the electrochemical reaction process significantly limits their widespread application. Herein, we present a V–Ni-based nitride heterojunction on carbon cloth (VN/Ni3N–Ni/CC) as an active electrode material for flexible supercapacitors. The VN/Ni3N–Ni/CC composite electrode was successfully fabricated through controllable nitridation of the corresponding vanadium–nickel oxide grown on carbon cloth (V–Ni–O/CC) precursors. The electrochemical results reveal that the areal capacitance of the VN/Ni3N–Ni/CC based supercapacitor with a nitriding temperature of 400 °C and a nitriding time of two hours can achieve a maximum areal capacitance of 845.63 mF cm−2 at a current density of 0.5 mA cm−2, and the electrode in the three-electrode system retains 86.1% of its initial capacitance value after 1500 cycles at a current density of 10 mA cm−2. In addition, the assembled flexible all-solid-state symmetric supercapacitor using the VN/Ni3N–Ni/CC electrode exhibits an areal capacitance ratio of 19.1 mF cm−2 at a current density of 0.4 mA cm−2 and excellent cycling stability. Moreover, it displays exceptional flexibility under different bending angles highlighting its potential for integration into flexible electronic devices. [ABSTRACT FROM AUTHOR]

As the adhesive for composites, the resin matrix directly impacts the molding process and product performance of thermoplastic composites (TPCs). Carbon fiber-reinforced polyetherimide (CF/PEI) and polyaryletherketone (CF/PAEK) composites were prepared by a compression molding process. The interface, interlaminar, and low-speed impact properties of TPCs were studied. The results show that the interfacial shear strength of the CF/PEI composite is ~116 MPa, while the CF/PAEK composite is ~78 MPa. However, the interlaminar and low-speed impact performance of CF/PAEK is better than CF/PEI. Type I fracture toughness ( G IC ) and type II fracture toughness ( G IIC ) of CF/PEI are ~1051 MPa and ~1060 MPa. But those of CF/PAEK are ~1786 MPa and ~2584 MPa, respectively. The compressive strength after the impact of CF/PAEK (~321 MPa) is 40% higher than CF/PEI (~230 MPa). [ABSTRACT FROM AUTHOR]

The development of a single polymer chain with the dual functions of self‐healing and degradation is challenging. Herein, we report the synthesis of self‐healing and degradable polymers (SDP) via the integration of hierarchical hydrogen bonding groups and degradable polycaprolactone (PCL) segments. The dynamic reconstruction of hierarchical hydrogen bonding endowed the as‐prepared polymers with excellent self‐healing properties. The degradation properties were regulated via the proportion of PCL in the soft segments. The incorporation of PCL segments resulted in better degradability and improved the tensile strength of the polymer from 9.2 to 28.3 MPa. The as‐prepared polymers could recover their mechanical properties after self‐healing. The temperature‐dependent Fourier‐transform infrared spectra (FT‐IR) indicated that the hierarchical hydrogen bonding was capable of dissociation and re‐association with a variation in the temperature. The as‐synthesized sustainable polymers, which exhibit self‐healing properties and degradability, are expected to be useful in future energy and environmental applications. [ABSTRACT FROM AUTHOR]

A recent research focus has been on developing sustainable and renewable high-performance electromagnetic shielding materials. We present here a robust and effective top-down method in which polydopamine (PDA) is added to delignified wood via in situ polymerization, and Ag particles are successfully deposited in the wood channel via PDA's adhesive property with a subsequent silver mirror reaction. According to our findings, when the AgNO3 content is 30 g/L, the conductivity of 2-mm-thick conductive wood reached 500 S/cm with an electromagnetic interference shielding efficiency of 50 dB in the X-band. The three-dimensional network structure of the wood is preserved, and thus it has good mechanical properties. Hence, silver-plated wood can be used as an electromagnetic shielding material that requires high strength. [ABSTRACT FROM AUTHOR]

The crystallization age of the Sunjiafen Formation volcanic rocks is 253.9 ± 1.1 Ma. Geochemical data show that these volcanic rocks belong to the shoshonitic and metaluminous series and have high Sr and low Y contents (461–582 and 5.60–6.74 ppm, respectively), MgO = 1.32–2.65 wt%, and Na2O/K2O = 0.81–1.40. In MgO−SiO2, Cr−SiO2, Sr/Y−Y and (La/Yb)N−YbN diagrams, data for the samples plot in the adakite and "adakite related to thickened lower crust" fields. As such, we suggest that the Sunjiafen Formation C−type adakitic andesites formed in a compressional tectonic setting. The youngest age (youngest peak age) of two sandstone samples from the Linxi Formation are 251 Ma (257 Ma) and 237 Ma (254 Ma). Detrital zircons with ages of >1500 Ma have εHf(t) values of −5.87 to +6.31. A comparison of the age spectra and εHf(t) values of the detrital zircons in the Linxi Formation with those of igneous zircons from the Central Asian Orogenic Belt and North China Craton indicates the formation was derived from both the belt and the craton. We identified "Jura–type Folds" that formed in peripheral foreland basin in the Linxi Formation, and along with plant fossil fragments (Paracalamites frigidus). These and previously published results indicate the Paleo–Asian Ocean closed along the Xar Moron–Changchun Suture zone during the Late Permian. The study area was in a continuous compressional setting during the Late Permian and formed a peripheral foreland basin that was related to continent–continent collision. [ABSTRACT FROM AUTHOR]

Self-powered flexible transparent ultraviolet (UV) photodetectors (PDs) have attracted great attention for next-generation portable and wearable optoelectronic device applications. However, it is still a challenge to fabricate high performance self-powered UV PDs with high flexibility and superior transparency. In this work, we report self-powered flexible transparent UV PDs with fast response speed, high transparency and excellent mechanical stability based on a CuO/ZnO nanowire (NW) array heterojunction on the Cu NW backbone. The device exhibits fast photoresponse times with a rise time of 16 ms and a decay time of 17 ms, a large photocurrent/dark current ratio of 392 and a high transparency of 80%. In addition, the as-fabricated self-powered UV PDs can retain good photoresponse performance when the device is bent even after 10 000 bending cycles, suggesting their superior mechanical stability. [ABSTRACT FROM AUTHOR]

The rock will be damaged and destroyed when the external load reaches the bearing limit, which will be accompanied by complex AE signals and damage evolution laws. Therefore, in order to obtain the relationship between AE signal and damage evolution characteristics of rocks, 4 kinds of sandstones of a mine are used for AE test. Firstly, the porosity of 4 kinds of sandstone is tested. Secondly, the AE signal parameter characteristics of sandstone with different porosity are analyzed. Finally, the AE parameters obtained are combined with cellular automata and damage theory to analyze the damage evolution law and critical damage value of different sandstones. The results show that the pore size of the four sandstones is QSYX > QSYZ > FSYX > FSYZ. The loading process is divided into compaction stage, elastic deformation stage, and plastic deformation stage, with peak strengths of 46.92 MPa, 43.32 MPa, 57.87 MPa, and 54.31 MPa, respectively. Or the AE event rate, the missing area, missing parts and missing number are different. The QSYX missing area is larger than QSYZ and FSYZ; the macrocrack growth speed is also faster; and the signs of fracture are obvious. The number of FSYX missing is more than QSYX, QSYZ, and FSYZ. The first two missing parts are caused by internal defects; the last two missing parts are signs of fracture; QSYX, QSYZ, and FSYZ are shear failure, and FSYX is tensile failure. The damage evolution process of the four sandstones corresponds to the loading process one by one. The calm stage of damage corresponds to the compaction stage, the damage expansion stage corresponds to the elastic deformation stage, and the damage acceleration stage corresponds to the plastic deformation stage. The critical damage values are 0.438, 0.499, 0.576, and 0.476, respectively, which are higher than the critical damage values of the sandstone cell model of 0.43, indicating that when the damage values reach the critical value, instability exists and instability failure will occur with continuous load. [ABSTRACT FROM AUTHOR]

The heating industries are extremely dispersed in China, and most heating enterprises are small in scale, poor in foundation, and chaotic in safety management. The construction method of the double prevention mechanism of heating enterprises in China was analyzed and studied based on the PDCA cycle model and the improved risk assessment method for operating conditions. The analytic hierarchy process was used to determine the weight of dangerous and harmful factors and corresponding control measures for an accident type. The concept of "failure frequency" was introduced, and the calculation method of accident probability (L) was modified so that the accurate hierarchical control and dynamic risk assessment of accident risks can be realized. At the same time, the failure of control measures is defined as "hidden danger" in this paper. Finally, the bidirectional dynamic transmission mechanism of hidden danger investigation and treatment and risk hierarchical control was established. The main problems existing in the construction of double prevention mechanism of heating enterprises in China were discussed and some countermeasures and suggestions were put forward. According to the above methods and steps, the double prevention mechanism of heating enterprises can be reasonably established. Thus, the risks can be effectively identified, the hidden dangers can be controlled, and the safety production of heating enterprises can be guaranteed. [ABSTRACT FROM AUTHOR]

SUMMARY: Simple telomeric repeats composed of six to seven iterating nucleotide units are important sequences typically found at the ends of chromosomes. Here we analyzed their abundance and homogeneity in 42 gymnosperm (29 newly sequenced), 29 angiosperm (one newly sequenced), and eight bryophytes using bioinformatics, conventional cytogenetic and molecular biology approaches to explore their diversity across land plants. We found more than 10 000‐fold variation in the amounts of telomeric repeats among the investigated taxa. Repeat abundance was positively correlated with increasing intragenomic sequence heterogeneity and occurrence at non‐telomeric positions, but there was no correlation with genome size. The highest abundance/heterogeneity was found in the gymnosperm genus Cycas (Cycadaceae), in which megabase‐sized blocks of telomeric repeats (i.e., billions of copies) were identified. Fluorescent in situ hybridization experiments using variant‐specific probes revealed canonical Arabidopsis‐type telomeric TTTAGGG repeats at chromosome ends, while pericentromeric blocks comprised at least four major telomeric variants with decreasing abundance: TTTAGGG>TTCAGGG >TTTAAGG>TTCAAGG. Such a diversity of repeats was not found in the sister cycad family Zamiaceae or in any other species analyzed. Using immunocytochemistry, we showed that the pericentromeric blocks of telomeric repeats overlapped with histone H3 serine 10 phosphorylation signals. We show that species of Cycas have amplified their telomeric repeats in centromeric and telomeric positions on telocentric chromosomes to extraordinary high levels. The ancestral chromosome number reconstruction suggests their occurrence is unlikely to be the product of ancient Robertsonian chromosome fusions. We speculate as to how the observed chromosome dynamics may be associated with the diversification of cycads. [ABSTRACT FROM AUTHOR]

Polysiloxanes have attracted considerable attention in biomedical engineering, owing to their inherent properties, including good flexibility and biocompatibility. However, their low mechanical strength limits their application scope. In this study, we synthesized a polysiloxane-based polyurethane by chemical copolymerization. A series of thermoplastic polysiloxane-polyurethanes (Si-TPUs) was synthesized using hydroxyl-terminated polydimethylsiloxane containing two carbamate groups at the tail of the polymer chains 4,4′-dicyclohexylmethane diisocyanate (HMDI) and 1,4-butanediol as raw materials. The effects of the hard-segment content and soft-segment number average molecular weight on the properties of the resulting TPUs were investigated. The prepared HMDI-based Si-TPUs exhibited good microphase separation, excellent mechanical properties, and acceptable repeatable processability. The tensile strength of SiTPU-2K-39 reached 21.5 MPa, which is significantly higher than that of other flexible polysiloxane materials. Moreover, the tensile strength and breaking elongation of SiTPU-2K-39 were maintained at 80.9% and 94.6%, respectively, after three cycles of regeneration. The Si-TPUs prepared in this work may potentially be used in gas separation, medical materials, antifouling coatings, and other applications. [ABSTRACT FROM AUTHOR]

As the most outstanding type of organic fiber in terms of the comprehensive performance, polyimide fiber is more conducive to reduce the composites weight than inorganic fibers, such as carbon fiber or glass fiber. A polyimide-fabric-reinforced polyether ether ketone (PEEK) composite was prepared by a hot-press molding process. The melt flow rate of the PEEK resin was measured to reveal its rheological behavior and guide the selection of the molding process parameters of the composite. The tensile properties of the composites were determined. The results revealed that the rheological properties of the resin manifested through the melt viscosity, which was more sensitive to pressure changes than to temperature changes. The tensile properties of the composites were affected by two competitive mechanisms. First, increases of molding temperature and duration time could facilitate the infiltration of the resin into the fiber fabric and improve the internal quality and tensile properties of the composite. Second, an excessively high molding temperature and long duration time could decrease the strength of the polyimide fiber, thereby reducing the tensile properties of the composites. [ABSTRACT FROM AUTHOR]

We report a simple strategy for improving the hydrophilicity of carbon black. Tannic acid (TA) and diethlyenetriamine (DETA) were employed to co-deposit on the surface of CB via immersing the CB in an alkaline TA and DETA solution with gently stirring at room temperature. The surface chemistry characteristics and hydrophilic of CB are investigated. The results suggest that a poly (tannic acid/diethlyenetriamine) (TA/DETA) layer with abundant hydrophilic groups such as hydroxyl and amino groups was successfully deposited on the surface of CB. Results of static contact angle indicate that the water contact angle is as low as 32°, which presents the excellent hydrophilicity of the modified CB. The deposition process of TA and DETA on the surface of carbon black. [ABSTRACT FROM AUTHOR]

A novel and cost-effective method for the fabrication of highly conductive Al/Ag core-shell structured microspheres was proposed and investigated. The oxidative co-deposition of catechol and polyamine was firstly performed to modify the surface of the aluminum microsphere. Then, a two-step electroless plating was conducted to fabricate the Al/Ag microspheres. During the first step of the electroless plating process, the surface of the aluminum microsphere was deposited with silver nanoparticle seeds using n-octylamine and ethylene glycol. Then, during the second step of the electroless plating process, silver particles grew evenly to form a compact silver shell on the surface of aluminum via a silver mirror reaction. According to the scanning electron microscope and energy dispersive X-ray results, a compact and continuous silver layer was successfully generated on the surface of the aluminum. The valence of the sliver on the surface of the aluminum was confirmed to be zero, based on the X-ray photoelectron spectrometer and X-ray diffractometer analyses. As a result, the as-prepared Al/Ag microspheres exhibited a high conductivity of 10,000 S/cm. The Al/Ag/MVQ composite demonstrated low electrical resistivity of 0.0039 Ω·cm and great electromagnetic interference shielding effectiveness at more than 70 dB against the X-band, and this result suggests that the as-prepared composite is a promising conductive and electromagnetic shielding material. [ABSTRACT FROM AUTHOR]

Flood events can significantly affect the physical and biological processes of aquatic ecosystems in a short time, leading to rapid changes in phytoplankton community structure. The Huayanghe Lakes experienced extreme flooding in the summer of 2020, with the water level reaching 16.42 m. In order to understand the effects of flooding on phytoplankton diversity and community structure, eight samples were collected in the Huayanghe Lakes from 2019 to 2020. Water-level disturbance has a significant influence on lake-water quality and phytoplankton community structure. The results showed that the Secchi depth increased from 65.36 to 8.52 cm, while the concentration of total nitrogen (from 0.98 to 0.7 mg/L) and total phosphorus (from 0.04 to 0.031 g/L) decreased. In addition, flooding significantly increased the Shannon–Wiener diversity index, the Pielou index, and the Margalef richness index by an average of 43.5%, 36.7%, and 40.21%, respectively. The phytoplankton community structure in the Huayanghe Lakes changed due to the change of physicochemical environment caused by flood. While in the pre-flood period phytoplankton was composed of large diatoms (e.g., Aulacoseira granulata), cyanobacteria (e.g., Microcystis sp., Anabaena sp., and Aphanizomenon sp.) and other multicellular taxa, the flood period showed an increase in the proportion of chlorophytes and diatoms that quickly adapted to settle in new environments. Pearson correlations and redundancy analyses showed that water level fluctuation was the most significant environmental factor affecting the phytoplankton community between the regular hydrological cycle and flood periods. There are few studies on phytoplankton in the Huayanghe Lakes, and the present study provides basic data on phytoplankton diversity and community structure. In addition, it provides a theoretical basis for controlling water level change in the Yangtze River. [ABSTRACT FROM AUTHOR]

Rapid and cost-effective scalability of the throughput of manufacturing systems is an invaluable feature for the management of manufacturing enterprises. System design for scalability allows the enterprise to build a manufacturing system to supply the current demand, and upgrade its throughput in the future, in a cost-effective manner, to meet possible higher market demand in a timely manner. To possess this capability, the manufacturing system must be designed at the outset for future expansions in its throughput to enable growths in supply exactly when needed by the market. A mathematical method that maximises the system throughput after reconfiguration is proposed, and an industrial case is presented to validate the method. The paper offers a set of principles for system design for scalability to guide designers of modern manufacturing systems. [ABSTRACT FROM AUTHOR]

The shear properties of bidisperse magnetorheological (MR) fluid have been extensively studied based on the experiment or simulation method, but the research on the enhancement mechanism is still not sufficient and need to be further investigated. In this paper, we proposed a new approach to analyze the mechanism based on the local microstructural models. The typical local configurations of particles in bidisperse MR fluid were determined by means of similarity experiment and confirmed by microstructure simulations. Subsequently, the evolution of local configurations under the shear process was simulated, and the corresponding shear resistance models were proposed. It is found that the configurations with small particles attached on sides of the chain can increase the shear resistance as well as the shear deformation, and the enhancement mechanism is determined based on the analysis of the relative position evolution of small and large particles in the local microstructures. The effect of particle size ratio on the properties of bidisperse MR fluid was also investigated. It is discovered that there is an optimal particle size ratio for MR fluid to achieve better performance. [ABSTRACT FROM AUTHOR]

The interfacial interactions between ultra‐high molecular weight polyethylene (UHMWPE) fiber and polymer determine the overall performance and service life of the fiber reinforced composite materials. In this article, polyaniline (PANI) layer is uniformly deposited on the surface of the UHMWPE fiber after plasma treatment to enhance the interfacial adhesion between UHMWPE fiber and rubber. At the same time, the PANI layer can also form a conductive path at the interface to monitor the damage of the composites in real time. Compared with the untreated UHMWPE fiber, the H pull‐out force of the PANI‐deposited UHMWPE fiber with rubber is increased by 67.9%, which is due to good mechanical interlocking and chemical bond between the fiber and the matrix. Moreover, the electrical resistance change during the fiber pull‐out process has a good correlation with the pull‐out force curve, which provides a new idea for in‐situ monitoring of the damage of composites. [ABSTRACT FROM AUTHOR]

The effects of pristine polystyrene microplastics (pMPs) without any pretreatment at different concentrations (0, 10, 20, 50, and 100 mg/L) on Phaeodactylum tricornutum Bohlin at two initial algae densities (105 and 106 cells mL) were assessed in this study. Hormesis-like effects were found when microalgae grew with pMPs. The results showed that pMPs inhibited microalgae growth under a high concentration of microplastics tolerated by individual algal cell (low initial algae density) (up to −80.18±9.71%) but promoted growth when the situation was opposite (up to 15.27±3.66%). The contents of photosynthetic pigments including chlorophyll a, chlorophyll c and carotenoids showed resistance to pMPs stress under a low initial algae density and increased with time, but the opposite was true under a high initial algae density. Compared with the low initial algae density group, Qp received less inhibition, and NPQ (heat dissipation) also decreased under the high initial algae density. Under the low initial algae density, OJIP parameters such as Sm, N, Area, Pi Abs, Ψo, φEo, TRo/RC and ETo/RC were more perturbed initially and returned to the levels of the control group (without pMPs) over time, but they remained stable throughout the experiment at high initial algae density. These results show that microplastics in the marine environment may have different toxic effects on P. tricornutum at different growth stages, which is of great significance for understanding the impact of microplastics on marine microalgae and aquatic ecosystems. [ABSTRACT FROM AUTHOR]

In order to improve the interfacial adhesion between aramid fiber (AF) and rubber matrix, a simple and facile method of aramid nanofiber (ANF) coating is demonstrated in this article. Tannic acid (TA) and polyethyleneimine (PEI) are polymerized in an alkaline solution to form a thin TA/PEI (TP) layer that is deposited on the surface of AF to introduce functional groups such as hydroxyl and amino groups. Then, the ANF coating is utilized to construct nanostructures on the surface of AF to improve the interfacial adhesion between the fiber and the rubber. Through hydrogen bonding and/or π‐π stacking between the TP layer and the ANF, the ANF coating is firmly attached to the surface of AF. Compared with the untreated fiber, the interfacial adhesion of AF coated with ANF after 1, 3, 5, 7, 9 deposition cycles is increased by 27.8%, 29.1%, 31.5%, 43.1%, and 30.3%, and the mechanical properties of the fibers remain almost unchanged. This method shows its advantages of simple, facile, and time‐effective, which is of great significance for industrial applications. [ABSTRACT FROM AUTHOR]

The migration and blooming of antioxidant molecules in the field of anti‐aging rubber is a challenge, where developing novel nanocarriers loaded with antioxidant molecules can solve the above problem. In this article, the surface thiol functionalized mesoporous silica nanorods loaded with antioxidant N‐(1,3‐dimethyl)butyl‐N′‐phenyl‐p‐phenylenediamine (MSN‐SH‐4020) was synthesized to avoid the blooming of antioxidants and then to improve the anti‐aging performance of styrene‐butadiene rubber (SBR). The migration of antioxidant molecules could be limited by encapsulating antioxidant in the pore of mesoporous silica nanorods, and the contend of antioxidant in the SBR reaches up to 1.33 wt%. The sustained release of antioxidant molecules from the pore increases the effective time of action of the antioxidant. After 168 hours of thermal oxidative aging test at 100°C, styrene‐butadiene rubber with 10 wt % surface thiol functionalized mesoporous silica nanorods loaded with 4020 (MSN‐SH‐4020) shows preservation of mechanical properties without blooming. This approach is highly perspective in many applications, such as long‐life sealing rubber and conveyor belts. [ABSTRACT FROM AUTHOR]

Due to the low output voltage of photovoltaic cells and fuel cells, a high-voltage-gain dc–dc converter is indispensable in the renewable energy power generation systems. In this article, a series of high-voltage-gain capacitor clamped dc–dc converters is constructed based on interleaved boost structures by considering the requirement of low input current ripple in fuel cell application. Furthermore, the construction method of capacitor clamped dc–dc converters is summarized according to the construction processes of these converters. Finally, the capacitor clamped dc–dc converter with the voltage gain of 3/(1−D) is analyzed in detail. Then, a 250-W prototype is built to validate the theoretical analysis and the construction method. [ABSTRACT FROM AUTHOR]

Both low clouds and elevated ducts are common phenomena in the oceanic atmosphere. Low clouds affect elevated ducts by changing the structure of atmospheric temperature and humidity. However, due to the limitation of met-ocean measurements, research on them is still scattered. This paper presents the distribution of elevated ducts and clouds over the central Western Pacific Ocean (WPO) based on Global Position System (GPS) sounding data and Himawari-8 satellite products from November 2015 to January 2016. Results show that the frequency of elevated ducts detected by ship-based GPS soundings was as high as 77% over the central WPO. The height and frequency of elevated ducts are closely related to the low clouds. If there are no clouds, the occurrence probability and mean base height of the elevated ducts are 14% and 730 m, respectively. By comparison, the occurrence probability and mean base height increase up to 24% and 1471 m, respectively, in the presence of cumulus (Cu) clouds, and 22% and 1511 m, respectively, in the presence of stratocumulus (Sc) clouds. Elevated ducts occur near the cloud top. The analysis of geopotential height and wind fields from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis dataset (ERA-interim) shows that the study area is covered by a strong and stable subtropical high, and slowly sinking dry air masses inside the subtropical high are above the moist boundary-layer air mass. The appearance and evolution of low clouds will adjust the temperature and humidity structure of the lower troposphere. If there are no clouds, the marine boundary layer (MBL) is the classic mixed boundary layer. Humidity gradient and subsidence inversion are formed atop the mixed layer. When low clouds are present, long wave radiation and entrainment atop clouds form a strong temperature inversion and humidity gradient, which strengthen elevated ducts. However, when Sc clouds are decoupled, a weaker temperature inversion and humidity gradient may occur between the surface mixed layer and subcloud layer, leading to a weak elevated duct atop the mixed layer. [ABSTRACT FROM AUTHOR]

This article, titled "[Retracted] MACC-1 antibody target therapy suppresses growth and migration of non-small cell lung cancer," was published in Molecular Medicine Reports in 2017. However, it has since been retracted due to concerns raised by a reader. The control data in Figure 2B and C were found to be strikingly similar to data from another article written by different authors at different research institutes. The authors were asked for an explanation but did not respond. The editor has apologized for any inconvenience caused. [Extracted from the article]

In this work, a green and efficient method for the surface modification of aramid fibers is proposed, aiming to enhance their adhesion property with rubber matrix. The surface of the aramid fibers was pre-deposited with a polyphenol-metal complex coating via rapid (1 min) complexation between FeIII ions and tannic acid (TA), followed by silane grafting. The influences of reactant concentration and reaction temperature on the grafting efficiency of bis-(γ-triethoxysilylpropyl)-tetrasulfide (Si69) were also characterized. The adhesion force of the modified aramid fibers/rubber composites showed a maximum improvement of 73.6% compared to that of untreated aramid fibers/rubber composites. This approach showed great potential in rubber industry due to its low-cost and high-efficiency. [ABSTRACT FROM AUTHOR]

Gardenia jasminoides, a well-known traditional Chinese herb, has been extensively utilized for its being as stable pigment in food industry and as rich source of crocin in treatment of various cancers and cardiovascular disease. Nevertheless, molecular data shortage of the organelle and nuclear genome vastly limits further biological research on G. jasminoides. In this study, complete chloroplast (cp) genome and large-scale nuclear genome sequences of G. jasminoides were initially generated by genome survey sequencing, and comprehensive genomic structure and comparison analyses were performed. The results showed that G. jasminoides cp genome displayed a typical quadripartite organization and was sized in 154,921 bp with 37.5% GC content. It contained 132 genes, 18 out of which were duplicated in the inverted repeat regions (IRs). Fifty long repeats (motif > 10 bp) and 27 simple sequence repeats were detected, and 30 usage-biased codons and 58 RNA-editing sites were predicted in G. jasminoides cp genome. The G. jasminoides cp genome was similar to those related species in Rubiaceae in terms of gene order and IR borders and a sister relationship of Gardenia and Coffea is strongly supported. Furthermore, the nuclear genome size of G. jasminoides was estimated to be 562.9 Mb, with heterozygosity rate being of 0.68%, repeat proportion of 51.6% and GC content of 36.44%. Overall, the data resources and findings generated in the present study will shed new light on the molecular and breeding studies on this important crocin-producing plant in the future. [ABSTRACT FROM AUTHOR]

Cancer and aging, two distinct processes of cell development, are two major problems threatening our human health and life in current days. Epigenetic studies, especially DNA methylation, have been intensively investigated on them over the years, though a lot of unanswered issues remain. In the human genome, rDNA is a highly conserved tandem repeat family playing critical roles in protein synthesis, genome stability and integrity, etc. More importantly, rDNA is the significant target of DNA methylation, and a potential association between rDNA methylation and cancer and aging has emerged recently. However, whether there is a general trend that rDNA methylation is associated with cancer and aging remains an open issue. In this study, the involvement of rDNA methylation in a series of records of cancer and aging was investigated and summarized, upon which perspectives about rDNA methylation in cancer and aging were proposed. The results showed that rDNA methylation in most cancer cases displayed a consistent pattern with hypermethylation in the coding region but with hypomethylation in the promoter region, which likely facilitates the proliferation and metastasis of cancerous cells. Distinctively, both the coding and promoter regions of rDNA become increasingly methylated during the process of aging, indicating the decline of rDNA activity. The finding of rDNA methylation also implies its potential application as an epigenetic biomarker in the diagnosis of cancer and aging. This work will shed light on our understanding of the pathogenesis, diagnosis, and treatment of cancer and aging from the perspective of rDNA methylation. [ABSTRACT FROM AUTHOR]

The evolutionary speed hypothesis (ESH) states that the molecular evolutionary rates of plants in the warm areas are higher than that in the cool areas. Nevertheless, largely due to the scarcity of molecular data from lower taxonomic lineages, ESH remains elusive in plants. In this study, we comprehensively conducted genome-wide comparative analyses of a total of 76 chloroplast (cp) genomes of the bamboos (Poaceae: Bambusoideae), with 10 of them newly generated, to test the ESH via investigating the potential association between their cp genome evolutionary rate and geographical distribution pattern. The results showed extreme heterogeneity of the evolutionary rate within the bamboos, with the lowest value found in temperate bamboos (tribe Arundinarieae) being approximately 1/4 of that in the tropical ones (tribe Olyreae). All the 91 non-coding loci and 75 coding loci evolve consistently faster in tribe Olyreae than that in tribe Arundinarieae. Most of the non-coding (82 out of 91) and coding (73 out of 75) loci in the tropical woody bamboos (tribe Bambuseae) also evolve faster than those in the temperate woody bamboos (tribe Arundinarieae). Moreover, the split of tropical and temperate bamboos was apparently accompanied with the change of cp genome evolutionary rate. This is by far the first case using cp genome data to support the ESH via showing the tropical plants evolve faster than their closely related temperate ones, and will shed new light on our understanding of ESH and the adaptation of plants. [ABSTRACT FROM AUTHOR]

China is one of the leading countries in the mining and utilization of coal resources, and the problems of coal-mining technology and safety have been concerned by the world, while the serious deformation and destruction of surrounding rock and the difficulty of support have brought inconvenience to the mining of coal resources due to repeated mining. This paper takes the actual engineering 22205 mining roadway in Buertai mine as the research background, through the combination of numerical simulation and field measurement. In this paper, the stress environment, plastic zone, and surrounding rock deformation in the advancing process of coal-mining face are studied, and the stress evolution law of surrounding rock in repeated mining roadway is obtained. It is clarified that the surrounding rock deformation is the failure mechanism under the combined action of principal stress difference and stress direction deflection. As a result, the surrounding rock of the roadway is asymmetrically deformed and destroyed, and the corresponding surrounding rock control scheme is put forward. The results show that the influence of repeated mining on roadway stress environment can be divided into four stages with the mining process: the stability stage of mining influence, the expansion stage of primary mining, the stable stage after primary mining, and the expansion stage of second mining. At the same time, the shape changes of the plastic zone and the displacement monitoring results of the monitoring are analyzed, and the results are obtained; the stage of stress change is suitable, and combined with the failure characteristics of surrounding rock in each stage, it is put forward that reinforcement measures should be taken in the stable stage after mining; the specific reinforcement scheme is determined according to the expansion form of plastic zone and field measurement. The on-site monitoring shows that there is no roof fall accident during the use of the roadway, which ensures the safety in production. [ABSTRACT FROM AUTHOR]

Background: Esophageal cancer (EC) is one of the aggressive gastrointestinal malignancies. It has been reported that microRNAs (miRNAs) play key roles during the tumorigenesis of EC. To identify novel potential targets for EC, differential expressed miRNAs (DEG) between EC and adjacent normal tissues were analyzed with bioinformatics tool. Methods: The differential expression of miRNAs between EC and adjacent normal tissues was analyzed. CCK-8 and Ki67 staining were used to detect the cell proliferation. Flow cytometry was performed to test the cell apoptosis. The correlation between miR-7-5p and KLF4 was detected by dual-luciferase report assay. Gene and protein expression in EC cells or in tissues were measured by qRT-PCR and Western blot, respectively. Cell migration and invasion were detected with transwell assay. Xenograft mice model was established to investigate the role of miR-7-5p in EC tumorigenesis in vivo. Results: MiR-7-5p was found to be negatively correlated with the survival rate of patient with EC. In addition, downregulation of miR-7-5p significantly inhibited the growth and invasion of EC cells. Meanwhile, miR-7-5p directly targeted KLF4 in EC cells. Moreover, downregulation of miR-7-5p inhibited the tumorigenesis of EC via inactivating MAPK signaling pathway in vivo. Conclusion: Downregulation of miR-7-5p notably suppressed the progression of EC via targeting KLF4. Thus, miR-7-5p might serve as a new target for the treatment of EC. [ABSTRACT FROM AUTHOR]

In this study, we report a facile method to fabricate silica-silver (SiO2/ PG-Fe3+/Ag) core–shell composite microspheres. The surface of SiO2 microspheres is functionalized with pyrogallol-ferric ions (PG-Fe3+) complexes, then Ag ions are reduced to Ag nanoparticles in situ onto the surface of SiO2 microspheres by electroless plating process. The Ag nanoparticles were uniformly coated on the surface of the SiO2 microspheres and formed a distinctive layer, which was confirmed by scanning electron microscopy characterization. The chemical compositions and microstructures of the microspheres were investigated by X-ray photoelectron spectroscopy and X-ray diffraction, respectively. The electrical conductivity of the prepared SiO2/ PG-Fe3+/Ag core–shell microspheres was about 1000 S/cm. When the microspheres were filled in methyl vinyl silicone rubber (MVQ), the obtained composites showed good mechanical and electrical properties, indicating their potential applications as conductive and electromagnetic shielding materials. [ABSTRACT FROM AUTHOR]

In this study, nutrient and heavy metal contamination in surface sediments of the Xiashan stream were investigated. Determining pollution degree of nutrient and heavy metal were the main objectives of this investigation. For this reason, the concentrations of total nitrogen (TN), total phosphorus (TP), seven heavy metals (Cu, Zn, Pb, Cd, Cr, Ni, Hg), and metalloid (As) were analyzed at 55 sampling sites. The mean TN concentration in surface sediments was 5.007 g/kg, while the mean TP concentration was 0.385 g/kg. Based on the sediment quality guideline (SQGs) and background values of Chinese soil and sediment, the majority of the mean TN concentrations in surface sediments were higher than their background values, while the TP concentrations were different from those observed for TN. For heavy metal concentrations in surface sediments, most of sampling stations were higher than their background values. The mean geo-accumulation (Igeo) indices for heavy metals were ranked as follows: Cd > Hg > Cu > Zn > Pb > Ni > Cr > As. The potential ecological risk index (RI) indicated heavy metal contamination level in Xiashan stream was very high ecological risk. According to Igeo and RI values, heavy metals especially Cd and Hg are influenced significantly by anthropogenic activities. Cd and Hg are not only as pollutant but also considerable contributor to ecological risk. Multivariate statistical investigations showed that there is a significant and positive correlation between Pb, As, and Cd. Cu, Ni, and Cr have similar characteristic and therefore probably originated from the same sources. Suggested by the results, it is necessary to control nitrogen and heavy metal contamination caused by human activities in the study area. [ABSTRACT FROM AUTHOR]

In renewable energy generation systems, the DC–DC converter with high voltage gain is indispensable, which is used to convert the low output voltage of photovoltaic (PV) cells and fuel cells to the high DC bus voltage. In this study, a cost-effective clamping capacitor boost (CCB) converter with high voltage gain is proposed. In the basis of the conventional boost converter, a clamping capacitor cell with two capacitors and two diodes is embedded. Then, the voltage gain of the proposed CCB converter can be doubled compared with the conventional boost converter. Further, unlike the switched capacitor high voltage gain converter, there is no large current spikes on the capacitors in the proposed CCB converter, which can reduce the current stresses and the costs of capacitors a lot. The operation principles and characteristics of the proposed CCB converter are analysed in detail and verified by simulation. Finally, a 450 W prototype is implemented to validate the performances and advantages of the proposed CCB converter. The proposed CCB converter provides a cost-effective choice for high voltage gain converters in the renewable energy generation system with PV cells. [ABSTRACT FROM AUTHOR]

The genus Acer, commonly known as maple, is a large plant lineage that comprises many economically and ecologically important species. However, because of low interspecific morphological variations and scarcity of molecular data, it is challenging to estimate the enigmatic phylogeny of Acer, limiting further utilization and conservation of maples. In this study, we generated complete plastomes of 17 species of maples representing 10 major sections of Acer and conducted comprehensively comparative genomic and phylogenomic analyses in Acer. The 17 plastomes are perfectly conserved in linear gene order and range narrowly in length of 155–157 kb with four constituent parts (LSC, SSC, IRa and IRb), whereas three IR types (amplum-, flabellatum- and yangbiense-like) are observed and the IR borders variation resulted in remarkable gene content divergence (132–134). In addition, there are apparently heterogeneous sequence divergences across the cp genome and 20 noncoding loci with fast evolutionary rates are further identified as potential molecular markers for subsequent studies on Acer. Furthermore, whole plastome sequences obtained the highest phylogenetic resolution and provided strong support for most backbone nodes of Acer among the seven analyzed data sets (LSC, SSC, IRs, coding, noncoding, 20-markers and whole-cp-genome), highlighting the significance of increasing informative sites in resolving intractable phylogenetic relationships of Acer. The section Negundo diverged firstly in Acer and close relationships among sects. Arguta, Ginnala, Macrantha, Oblonga, Pentaphylla, Platanoidea and Trifoliata were uncovered. Interspecific relationships within species-rich sects. Macrantha, Palmata and Platanoidea are also clearly resolved by plastid phylogenomics. [ABSTRACT FROM AUTHOR]