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In this study, a novel colorimetric screening method for identifying menaquinone-7 (MK-7) producing strains was established using potassium permanganate. To our knowledge, this method represents the first direct screening methodology for the identification of MK-7 producing strains. Utilizing this screening method, a new MK-7 producing strain, Bacillus subtilis GSA-184, was identified from the soil of the Tibetan Plateau. Under the optimized fermentation medium (50 g/L glycerol, 30 g/L yeast extract powder, 100 g/L soybean peptone, 1 g/L KH2PO4, and 1 g/L MnSO4), the production of MK-7 was increased to 25.7 mg/L. Additionally, the maximum production of MK-7 reached 36.46 mg/L after 48 h in a 5-L fermenter. [ABSTRACT FROM AUTHOR]

A self-adaptive energy storage coordination control strategy based on virtual synchronous machine technology was studied and designed to address the oscillation problem caused by new energy units. By simulating the characteristics of synchronous generators, the inertia level of the new energy power system was enhanced, and frequency stability optimization was achieved. This strategy is integrated with the frequency response model of the new energy power system to improve the system's frequency regulation capability and achieve more stable and efficient operation. From the results, the damping of the system increased, the oscillation frequency decreased after a duration of about 15 s, and the system stability improved by 76.09%. The proposed strategy based on virtual synchronous generator adaptive energy storage coordination control strategy was improved by 83.25%. In addition, the proposed strategy has improved stability indicators and system completion efficiency by 40.57% and 22.21% respectively, both of which are better than the comparative strategies. As a result, this strategy significantly enhances the frequency regulation capability of the system, which has a positive effect on achieving efficient operation of the new energy power system and maintaining the stability of the power system. [ABSTRACT FROM AUTHOR]

Global warming has caused poleward mangrove expansion, but extreme climatic events have significantly impacted the mangroves along their boreal limits. This study aimed to determine which natural hazard is more important in limiting the sustainability and survival of subtropical black mangroves—hurricanes or freezing events? Satellite and drone images indicated Hurricanes Zeta and Ida (2020–2021) caused only minor impacts on mangrove area (~ 5%, 6.32 ha) compared with the extensive mangrove degradation (defoliation and dry branches) caused by the winter freeze of Dec/2017–Jan/2018 (~ 89%, 110 ha) at Port Fourchon, LA. However, mangroves impacted by that winter freeze had a faster recovery (~ 1 year), while the losses of mangrove areas caused by those hurricanes were longer-lasting. This finding is novel and important because it implies that subtropical mangroves have low resistance but high resilience to winter freezes, while these forests present high resistance but low resilience to hurricanes. Overwash processes driven by hurricanes are the primary threat to mangroves at Port Fourchon due to the high rate of beach barrier retreat, which causes the burial of the back-barrier wetlands. Beach renourishment projects are essential to guarantee the stability of the beach barrier and slow down the increased losses of mangrove and salt marsh areas caused by hurricanes and relative sea level rise. [ABSTRACT FROM AUTHOR]

Crumb rubber concrete (CRC) is a cementitious composite produced by incorporating rubber crumbs into normal concrete (NC), characterized by large deformation, high damping, high energy absorption, and lower Young's modulus than normal concrete. This article presents a study on the seismic performance of frame structures under four scenarios: one normal concrete frame and three CRC frames. The total lateral stiffness, fundamental period, lateral earthquake loading, and interstory lateral displacements are calculated and compared based on the standardized design procedure. The results indicate that CRC frame structures increase the fundamental period and reduce the lateral earthquake loadings. The fundamental period of the CRC columns and beams (S3) is increased by 5.48% against normal concrete beams and columns (S0). However, decrease in the total lateral stiffness and increase the interstory lateral displacements was observed. The lateral earthquake loading is reduced by more than 4% against S0. These two competing factors determine the plausibility and benefit of CRC in structural application regarding earthquake design. The inter-story lateral displacements of CRC structures are still within the permissible design limits, confirming CRC's plausibility in structural application. This study also lays the technical ground for further exploring CRC in concrete structural applications that may recycle large quantities of scrap automobile tires. [ABSTRACT FROM AUTHOR]

Stripe rust is a devastating disease of wheat worldwide. Chinese wheat cultivar Lanhangxuan 121 (LHX121), selected from an advanced line L92-47 population that had been subjected to space mutation breeding displayed a consistently higher level of resistance to stipe rust than its parent in multiple field environments. The aim of this research was to establish the number and types of resistance genes in parental lines L92-47 and LHX121 using separate segregating populations. The first population developed from a cross between LHX121 and susceptible cultivar Xinong 822 comprised 278 F2:3 lines. The second validation population comprised 301 F2:3 lines from a cross between L92-47 and susceptible cultivar Xinong 979. Lines of two population were evaluated for stripe rust response at three sites during the 2018–2020 cropping season. Affymetrix 660 K SNP arrays were used to genotype the lines and parents. Inclusive composite interval mapping detected QTL QYrLHX.nwafu-2BS, QYrLHX.nwafu-3BS, and QYrLHX.nwafu-5BS for resistance in all three environments. Based on previous studies and pedigree information, QYrLHX.nwafu-2BS and QYrLHX.nwafu-3BS were likely to be Yr27 and Yr30 that are present in the L92-47 parent. QYrLHX.nwafu-5BS (YrL121) detected only in LHX121 was mapped to a 7.60 cM interval and explained 10.67–22.57% of the phenotypic variation. Compared to stripe rust resistance genes previously mapped to chromosome 5B, YrL121 might be a new adult plant resistance QTL. Furthermore, there were a number of variations signals using 35 K SNP array and differentially expressed genes using RNA-seq between L92-47 and LHX121 in the YrL121 region, indicating that they probably impair the presence and/or function of YrL121. [ABSTRACT FROM AUTHOR]

How atmospheric and oceanic circulations respond to Arctic warming at different timescales are revealed with idealized numerical simulations. Induced by local forcing and feedback, Arctic warming appears and leads to sea-ice melting. Deep-water formation is inhibited, which weakens the Atlantic Meridional Overturning Circulation (AMOC). The flow and temperature in the upper layer does not respond to the AMOC decrease immediately, especially at mid-low latitudes. Thus, nearly uniform surface warming in mid-low latitudes enhances (decreases) the strength (width) of the Hadley cell (HC). With the smaller northward heat carried by the weaker AMOC, the Norwegian Sea cools significantly. With strong warming in Northern Hemisphere high latitudes, the long-term response triggers the "temperature-wind-gyre-temperature" cycle, leading to colder midlatitudes, resulting in strong subsidence and Ferrel cell enhancement, which drives the HC southward. With weaker warming in the tropics and stronger warming at high latitudes, there is a stronger HC with decreased width. A much warmer Southern Hemisphere appears due to a weaker AMOC that also pushes the HC southward. Our idealized model results suggest that the HC strengthens under both warming conditions, as tropical warming determines the strength of the HC convection. Second, extreme Arctic warming led by artificially reduced surface albedo decreases the meridional temperature gradient between high and low latitudes, which contracts the HC. Third, a warmer mid-high latitude in the Northern (Southern) Hemisphere due to surface albedo feedback (weakened AMOC) in our experiments pushes the HC northward (southward). In most seasons, the HC exhibits the same trend as that described above. [ABSTRACT FROM AUTHOR]

Wheat stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) is an airborne disease that endangers wheat during its entire growth period. In this study, the Pst134EA_003354 uncharacterized protein (GenBank: XM_047941824.1) of Pst was used as the target sequence, and the primers PS-RPA-F and PS-RPA-R, as well as the probe PS-LF-probe, were designed for recombinase polymerase amplification (RPA) technology. Flow chromatography was combined with the process to establish an RPA detection method for Pst. This method successfully established visual detection within 10 min under a constant temperature of 39 °C, and the detection results were consistent with those of ordinary PCR analysis. However, it only had high specificity for Pst, and the detection limit was 10 fg/μL. In addition, this rapid method successfully detected Pst from wheat leaves during the field incubation period, indicating substantial benefits for applied use. In summary, the RPA detection method established in this study has the favourable characteristics of high efficiency, simple functionality, and rapid and universal practicability, providing a theoretical basis for the early detection and prevention of Pst. [ABSTRACT FROM AUTHOR]

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Context: SF6 gas has a strong greenhouse effect, and how to treat SF6 in an environmentally friendly way has been a hot topic of current research. In this paper, the adsorption behavior of SF6 on the surface of Pd-doped hydroxyl-terminated modified Ti3C2Tx (i.e., Ti3C2(OH)2) was investigated based on the density functional theory using two-dimensional MXene as the catalyst. The structures of different Pd-doped Ti3C2(OH)2 were analyzed and the most structurally stable doped structures were selected as the basis for subsequent calculations. A large number of adsorption configurations were constructed and geometrically optimized, and the adsorption energy, charge transfer, differential charge density, and density of states of the systems were calculated in order to analyze the gas–solid interactions and find the surface active sites; compared with the adsorption performance of undoped Ti3C2(OH)2 on SF6, it was found that Pd doping played a less inhibitory role in the adsorption of SF6 on the Ti3C2(OH)2 surface. The results of this study can provide theoretical support for the use of Pd-doped Ti3C2(OH)2 as a catalyst for the degradation of SF6. Methods: In this paper, simulations of SF6 adsorption on Ti3C2Tx surfaces are based on density functional theory and are carried out in the Dmol3 module of Material Studio. To better describe the non-uniform electron density of the actual system, the PBE functional in the generalized gradient approximation (GGA) was chosen for the optimization of the structure of the gas–solid interface system and the calculation of the relevant electronic properties, combined with the Grimme dispersion correction in the DFT-D dispersion correction for the electron exchange correlation term. Because both Pd and Ti are transition metal elements, the mode-conserving pseudopotential DNP basis set containing relativistic effects was chosen for the electronic wave function expansion. In this paper, an all-electron model is used for the inner core treatment of gas molecules and a density generalized semi-nuclear pseudopotential DSSP is used for the solid surface treatment. [ABSTRACT FROM AUTHOR]

Background: Whether smoking is a risk factor for ischemic stroke (IS) recurrence in IS survivors is still uncovered, and evidences are sparse. Meanwhile, an add-on effect of clopidogrel was observed in myocardial infarction patients who smoked, but whether the paradox exists in IS patients is still unsolved. The objectives of this study are to explore the association between smoking behavior after index stroke and IS recurrence and to explore whether the paradox exists. Methods: A prospective cohort of first-ever IS patients was conducted between 2010 and 2019. The prognosis and smoking features of enrolled patients were obtained via telephone follow-up every 3 months. Fine-gray model with interaction terms was applied to measure the relationships between stroke recurrence and smoking behaviors after index stroke and to explore the add-on effect of clopidogrel in smoking patients. Results: There were 171 (24.26%) recurrences and 129 (18.30%) deaths during follow-up in 705 enrolled IS patients. One hundred forty-six (20.71%) patients smoked after index stroke. The hazard ratios (HRs) and 95% confidence intervals (CIs) of interaction terms between antiplatelet drug and follow-up smoking (smoking status and daily smoking amount) were 1.092 (95% CI: 0.524, 2.276) and 0.985 (95% CI: 0.941, 1.031), respectively. A significantly higher risk of recurrence was observed in patients with a higher daily smoking amount during follow-up (per cigarette), with HR being 1.027 (95% CI: 1.003, 1.052). Conclusions: Smoking could elevate the risk of IS recurrence, and IS survivor should be advised to quit or smoke less. Add-on effect of clopidogrel may not exist in smoking strokers taking clopidogrel. [ABSTRACT FROM AUTHOR]

In recent years, debris flows have frequently erupted in the narrow-steep gully of the earthquake-hit Wenchuan region, displaying high flow velocities and powerful scouring abilities. However, few scouring studies in the narrow-steep gully have been conducted. A model experiment simulated the debris flow scouring process in a narrow-steep flume, in which several important physical parameters, including the debris flow density (ρ), flume slope (θ), and grain size of the sediment (D), were varied to investigate their influences on the erodible strength. The experimental flows were composed of 50 L of water and grains, which scoured 2.3 m of erodible bed down a steeply inclined flume. A high-speed camera photographed the scouring processes, while a 3D laser device captured the final bed shapes. The experiments show that the debris flow first collides with the sediment at the head of the gully to form a pit, which is enlarged by continuous impact; the velocity of the debris flow out of the pit is significantly reduced due to the change in flow direction, resulting in a much lesser scouring effect after the pit; and finally, the gully bed presents the shape of a pit at the entrance and a groove in the middle and rear. The critical scour slope, where the gully bed shows scouring, increases with increasing debris flow density but decreases with increasing grain size of sediment. Following scouring, the maximum scouring depth is further positively correlated with the flume slope. In narrow-steep gullies, the gully bed is extremely susceptible to scouring by debris flow with a low density, and even headward erosion appears, at which the maximum scouring depth only increased from 148.04 to 149.97 mm, but the erosion amount had a significant increase of 36.9%. The research results have an important significance for revealing the disaster-causing phenomena and mechanisms of debris flows in the narrow-steep gully. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A good understanding driver behavior is significant in the development of chassis control system and autonomous vehicles. To better simulate human drivers, the driver model with the local path rolling planning decision is developed based on model predictive control algorithm. Firstly, three local path planning methods of straight-line driving, circular-arc driving and B-spline curve driving are designed to describe the different steering styles. Secondly, the linear time-varying (LTV) MPC controller is established to follow the local planned path. Finally, the two typical simulations are carried out and compared with the single-point preview driver model and the optimal preview driver model. And, the results indicate that the proposed driver model is suitable for simulating diversity of the human driver's driving characteristics. [ABSTRACT FROM AUTHOR]

As a transition metal dichalcogenides (TMDCs), molybdenum disulfide (MoS2) comprises individual sheets stacked into a bulk-phase structure. Compared with bulk-phase MoS2, the few-layer MoS2 presents a two-dimensional nanostructure similar to graphene, which has the advantages of large specific surface area and many unsaturated vacancies in the edge layer and has broad application prospects in the fields of photoelectricity and catalysis. Here, a simple and practical method of exfoliating bulk-phase MoS2 is proposed. The bulk-phase MoS2 was sonicated using chitosan/acetic acid (CS/HAc) solution to obtain oligomeric MoS2. The raw materials used in this method have good biocompatibility, the preparation process and operation are simple, and the pollution caused to the environment is small, which meets the green chemical standard. The method provides a new idea and way for the peeling treatment of other laminated materials. The results show that the stacking of (002) crystal plane of MoS2 samples after treatment with CS/HAc solution is reduced and the crystalline phase is changed from polycrystalline to single-crystal structure, which has great potential for applications in optical and electrical fields. [ABSTRACT FROM AUTHOR]

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In gas-insulated equipment, the decomposition of SF6 is closely related to the residual traces of O2 and H2O in the equipment. However, the decomposition mechanism has not yet been clarified. In this paper, the adsorption and defluorination of SF6 on the preadsorbed Cu(111) surface were calculated based on density flooding theory and transition state theory. Besides, the influence mechanism of O atoms and H2O molecules on the defluorination process is analyzed by comparing the energy barrier, reaction heat, and density of states. The results show that pre-adsorption of O atoms changes the adsorption sites of SFx, but has no significant effect on the adsorption energy. In addition, the O atom has a certain inhibitory effect on the decomposition process, and SF → S + F is the key to determining the reaction rate. In contrast, H2O will not only promote the adsorption of SFx to the surface but also reduce the total reaction heat of the decomposition reaction by 135.37 kcal·mol−1, driving the decomposition process of SF6. In this paper, stable co-adsorption configurations of low-fluorosulfide and co-adsorption groups were determined, and the effects of O and H2O preadsorption on SF6/Cu gas–solid interactions were initially revealed. [ABSTRACT FROM AUTHOR]

By applying a recent result on the distributions of full and non-full words, we give a proof of the useful folklore result: the Hausdorff dimension of an arbitrary set in the shift space is equal to the Hausdorff dimension of its natural projection in [0, 1]. It has been used in some former papers without proof. Then we clarify that in order to calculate the Hausdorff dimension of frequency sets using variational formulae, one only needs to focus on the Markov measures of explicit step when the β -expansion of 1 is finite. Finally, as an application, we obtain an exact formula for the Hausdorff dimension of frequency sets for an important class of β 's, which are called pseudo-golden ratios (also called multinacci numbers). [ABSTRACT FROM AUTHOR]

Accurately grasping the decomposition path of SF6 on the surface of typical metals and metal oxides is the key to reveal the decomposition mechanism of overheating fault. In this paper, the decomposition paths of SF6 on Cu and its oxides are theoretically analyzed by combining density functional theory and transition state theory. The results show that the participation of Cu surface reduces the energy required for the initial decomposition of SF6 by about 98.70 kcal/mol compared to that in free space. The decomposition reaction of SF5 on the Cu surface is energy barrier free, thus SF5 cannot stably exist in SF6 over-thermal decomposition system. Further, it was found that when Cu was oxidized at high temperature, reactions between SF6 and metal surface would be more intense. At this time, the total reaction heat of SF6 completely decomposed into S was -220.07 kcal/mol, significantly lower than -100.60 kcal/mol on Cu surface. This illustrates the catalytic effect of Cu and its oxides. On the surface of CuO, the interaction of O and F atoms may be the main reason to further reduce the activation energy. This article explained the over-thermal decomposition process of SF6 from microscopic level, laying a theoretical foundation for further study on the influence of the over-thermal decomposition of SF6-metal system. [ABSTRACT FROM AUTHOR]

Corn stover could be pyrolysed to prepare biochar for removing pollutants in water and realizing the resource utilization of biomass. The aims of the present study were to investigate the optimal preparation and adsorption conditions of biochar and to reveal the adsorption characteristics and mechanisms of Cd2+ in water by biochar. For this purpose, with Cd2+ as the target pollutant, the pyrolysis conditions involved in the pyrolysis temperature, retention time, and heating rate were evaluated and optimized. Additionally, the characteristics, mechanisms and optimal adsorption conditions of Cd2+ by biochar were determined. A series of characterization techniques was employed, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and specific surface area analysis (SBET). The optimum pyrolysis parameters were a pyrolysis temperature of 700 °C, a retention time of 2.5 h, and a heating rate of 5 °C/min. Acid/base modification did not improve the adsorption capacity of biochar. The Langmuir and the Elovich model were the most suitable isotherm and kinetic models for equilibrium data, respectively. The maximum adsorption capacity fitted by Langmuir model was 13.4 mg/g. Furthermore, mineral precipitation and π electron interactions were shown to be the main adsorption mechanisms of Cd2+. The optimum adsorption conditions for Cd2+ in water were a CaCl2 electrolyte solution of 0.01 mol/L, a pH level of 6.7, and a biochar dosage of 0.4 g. Our results indicated that corn stover biochar was an appropriate approach for improving the status of water with Cd2+ contamination in the short term and for promoting a new perspective for the rational utilization of corn stover and the low-cost pollution control of heavy metals in water. [ABSTRACT FROM AUTHOR]

The 2021 Madoi M7.4 Earthquake in Qinghai is a major earthquake that occurred in the Bajankara Block of Qinghai-Tibet Plateau in the past 30 years, which spatially filled the seismogenic gap in the eastern section of the northern boundary of the block. Here we determined the values of ML, MS_BB, mB, MWp, MWW, Mdt, and M (GNSS) by abundant regional and global seismic and geodetic observations, which is 6.61, 7.43, 7.18, 7.33, 7.43, 7.38, and 7.4, respectively. To compare the time efficiency and stability of different magnitude scales, we generated a real-time environment, to iteratively determine the magnitudes over elapsed times. Some methods such as mB, MSBB, MWp gave considerable variations of as large as 0.5 units for the determined magnitudes with elapsed time, as more data were included. Others such as MWW and Mdt were very stable with increasing data over time. The systematic calculations of various magnitude scales in this study quantitively evaluated the stability and accuracy of those methods, shading light on the adaptability and applicability of different magnitude scales. [ABSTRACT FROM AUTHOR]

This study focuses on rapidly determining seismic intensity maps of earthquakes because it offers fundamental information for effective emergency rescue and subsequent scientific research, and remains challenging to accurately determine seismic intensity map in regions with sparse instrumental observations. Here we applied a novel method that consisted of array technology (back-projection), ground-motion prediction equations, and site corrections, to estimate the seismic intensity maps of the 2021 Mw 7.3 Madoi, Qinghai and the Mw 6.1 Yangbi, Yunnan, China earthquakes. We used seismic data recorded at European stations to back-project the source processes of the 2021 Mw 7.3 Madoi, Qinghai and the Mw 6.1 Yangbi, Yunnan, China earthquakes. The back-projected energy radiations were then used as subevents or used to define the fault geometry. Summing the contributions of each subevent or estimating the shortest distances from each site to the rupture fault, we obtained the ground motion (PGA and PGV) for each site under rock site conditions. The estimated ground motions were corrected at each site for local site amplification according to the Vs30 database. Our estimated seismic intensity maps and field reports showed high similarity, which further validated the effectiveness of the novel approach, and pushed the limit of earthquake size down to ∼M 6. Such efforts would substantially help in the fast and accurate evaluation of earthquake damage, and precise rescue efforts. [ABSTRACT FROM AUTHOR]

Since deformation modulus of rock mass is an important parameter for analyzing the mechanical properties of roadway surrounding rock in coal mines, accurate acquisition of the deformation modulus of roadway surrounding rock is essential for mining design, roadway support, and disaster prevention. To achieve this aim, the roadway surrounding rock in Chahasu Coal Mine was taken as the research case. First, uniaxial compression experiments and true triaxial compression experiments were carried out on coal and rock samples. The laboratory deformation modulus of rock mass was determined by stress–strain curves, and the in situ deformation modulus of rock mass in coring boreholes was obtained with the aid of the GY-75 borehole jack. Meanwhile, based on the results of rock mass quality evaluation, the estimated values of deformation moduli of roadway surrounding rock were obtained through an empirical equation. As displayed through the comparative study on the relations between deformation moduli obtained by different methods, with the increase of rock mass depth, in situ deformation modulus increases gradually with reduced growth amplitudes, and its spatial distribution characteristics can be expressed by an exponential function. For roadway surrounding rocks at the same depth, the relation between in situ deformation modulus and deformation moduli obtained from the uniaxial compression experiment and the true triaxial compression experiment can be given by an exponential function and a linear function, respectively. The empirical equation based on the single index RMR shows strong applicability in estimating the deformation modulus of roadway surrounding rock. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In gas-insulated equipment, partial over-thermal faults may occur due to poor contact and other reasons. The main insulation medium SF6 may decompose under over-thermal conditions and produce harmful products such as SO2 and HF, which can damage the equipment and reduce the insulation strength of the equipment. The method of decomposition component analysis can monitor the operating status of equipment without interference from machinery, noise and optics, and provide early warning or reminder of faults, but the premise is that the decomposition mechanism of SF6 must have been fully and in-depth understood. In the decomposition process of SF6, O2 has a significant effect, but the mechanism of the effect is still unclear. Based on the isotope tracing method, this paper uses 18O2 instead of ordinary O2 for overheating experiments. Through the quantitative detection of the labeled products in the product and the abundance of 18O isotope in the products, the effect of O2 on the formation of the main decomposition products was analyzed. The work makes the reaction process and mechanism of SF6 with trace oxygen under over-thermal conditions basically clear, which provides an important theoretical basis for on-line monitoring and fault diagnosis of equipment based on chemical analysis methods. [ABSTRACT FROM AUTHOR]

Since the environmental-friendly insulating gas C5F10O not only has good environmental compatibility, but also has excellent insulating properties, it has the potential to replace SF6 in equipment such as medium and low voltage switchgear. When a partial over-thermal fault occurs on metal material surface inside the gas-insulated equipment, the C5F10O can be decomposed by overheating, and the presence of the gas–solid interface has a certain influence on C5F10O decomposition process. To this end, this article uses the Density Functional Theory to study on C5F10O over-thermal decomposition mechanism on metal materials surface in the equipment. The results show that when it does not involve Cu atoms in the reaction, the energy barrier of C5F10O decomposed into C2F4O and C3F6 is reduced by about 14.7 kcal/mol compared with that in free space; when C5F10O decomposition involves Cu atoms in the reaction and chemical adsorption occurs, the reaction energy barrier is further reduced by about 7.4 kcal/mol. In addition, the participation of Cu surface reduces the reaction energy barrier of 2 C2F4O → CF2O + C3F6O and C2F4O → CF4 + CO by 8.4 kcal/mol and 26.6 kcal/mol respectively, and increases the reaction energy barrier of C3F6 + CF2O → C3F8 + CO by 23.4 kcal/mol. It is believed that copper material has the effect of promoting the C5F10O decomposition to some degree. The research conclusions in this article can provide theoretical guidance for selections of internal metal materials or surface coating for the design of environmentally friendly gas-insulated switchgear in the future. [ABSTRACT FROM AUTHOR]

The relationship between exercise and stroke recurrence is controversial. This study was designed to test whether an association exists between exercise and ischemic stroke recurrence in first-ever ischemic stroke survivors. Data were collected from January 2010 to June 2016. Baseline information was obtained during face-to-face interviews, and follow-up phone interviews were conducted every 3 months. Exercise type, frequency, intensity, and duration were recorded. Discrete-time survival analysis was used to determine the relationship between exercise and stroke recurrence. 760 first-ever ischemic stroke survivors who were able to exercise were enrolled. After adjusting for covariates, patients who exercised 3.5–7 h per week and more than 7 h per week had a lower relapse risk than patients who did not exercise (3.5–7: OR 0.415; > 7: OR 0.356). Moreover, if the fluctuation of exercise duration was over 4 h, the patients had a higher risk of stroke recurrence than those with variability of less than 2 h (OR 2.153, P = 0.013). Stroke survivors who engage in long-term regular mild exercise (more than 5 sessions per week and lasting on average 40 min per session) have a lower recurrence rate. Irregular exercise increases the risk of stroke recurrence. [ABSTRACT FROM AUTHOR]

Given an integer q ≥ 2 and θ 1 , ... , θ q - 1 ∈ { 0 , 1 } , let (θ n) n ≥ 0 be the generalized Thue–Morse sequence, defined to be the unique fixed point of the morphism 0 ↦ 0 θ 1 ⋯ θ q - 1 1 ↦ 1 θ ¯ 1 ⋯ θ ¯ q - 1 beginning with θ 0 : = 0 , where 0 ¯ : = 1 and 1 ¯ : = 0 . For ad hoc rational functions R, we evaluate infinite products of the forms ∏ n = 1 ∞ (R (n) ) (- 1) θ n and ∏ n = 1 ∞ (R (n) ) θ n. This generalizes relevant results given by Allouche, Riasat and Shallit in 2019 on infinite products related to the famous Thue–Morse sequence (t n) n ≥ 0 of the forms ∏ n = 1 ∞ (R (n) ) (- 1) t n and ∏ n = 1 ∞ (R (n) ) t n. [ABSTRACT FROM AUTHOR]

Accurate knowledge of the distribution characteristics of structural planes in rocks is beneficial in the evaluation of rock mass quality and roadway support decision-making. In this study, in situ monitoring results were used to analyse the deformations and failure characteristics of the rock surrounding the main haulage roadway in the Huahong coal mine to establish a deformation and failure model for the surrounding rock affected by mining. According to an analytic hierarchy process, a comprehensive evaluation index for the degree of fracturing in the rock surrounding the coal seam roadways was proposed. Additionally, a classification method based on the comprehensive widths of the structural planes (CWSPs) inside the complete rock mass was proposed to determine the quality of the surrounding rock. The structures of the rocks surrounding the main haulage roadway in the mine before and after coal mining were observed in situ at monitoring station no. 22. Borehole imaging technology was used to classify the surrounding rock quality using the CWSP-based evaluation method. The results indicated that the roof rock was mildly affected by mining; the corner rock had a large degree of fracturing in the central part of the borehole and a small degree of fracturing at both ends; the rib rock was highly fractured. These evaluation results were consistent with the macroscopic characteristics of the surrounding rocks, indicating the reliability of the deformation and failure model for characterizing the surrounding rocks affected by mining. [ABSTRACT FROM AUTHOR]

This paper aimed to provide an approach to investigate the historical roots and evolution of research fields in China by extending the reference spectroscopy year spectroscopy (RPYS). RootCite, an open source software accepts raw data from both the Web of Science and the China Social Science Citation Index (CSSCI), was developed using python. We took iMetrics in China as the research case. 5141 Chinese iMetrics related publications with 73 376 non-distinct cited references (CR) collected from the CSSCI were analyzed using RootCite. The results showed that the first CR in the field can be dated back to 1882 and written in English; but the majority (64.2%) of the CR in the field were Chinese publications. 17 peaks referring to 18 seminal works (13 in English and 5 in Chinese) were located during the period from 1900 to 2017. The field shared the same roots with that in the English world (e.g., Lotka's law and Garfield's "Citation Indexes") but has its own characteristics, and it was then shaped by contributions from both the English world (e.g., Small's "Co-citation" and Callon et al.'s "Co-word analysis") and China (e.g., Qiu's "Bibliometrics" and Su's "CSSCI"). The three Chinese works have played irreplaceable and positive roles in the historical evolutionary path of the field, which should not be ignored, especially for the evolution of the field. This research demonstrated how RootCite aided the task of identifying the origin and evolution of research fields in China, which could be valuable for extending RPYS for countries with other languages. [ABSTRACT FROM AUTHOR]

Few studies have documented the characteristics of fluvial flooding-induced storm deposits associated with a modern hurricane. Hurricane Harvey (2017) caused extensive flooding in coastal Texas due to a combination of storm surge and heavy precipitation. This study investigates the depositional process associated with Hurricane Harvey by means of loss-on-ignition (LOI) and X-ray fluorescence (XRF) analyses of 9 short cores and 17 surface samples collected from the San Bernard National Wildlife Refuge (SBNWR), Texas. Hurricane Harvey caused the largest flood within SBNWR over the last 28 years, and freshwater flooding from the San Bernard River was the predominant cause of this inundation. A distinct washover sand layer is lacking at all coring sites, but the intrusion of seawater can still be detected by a peak in the chlorine/bromine (Cl/Br) ratio of most sediment cores. Our study shows that Cl/Br ratios are higher in coastal environments than in terrestrial environments, thereby confirming that this elemental ratio can be used as a salinity indicator and, as a corollary, evidence of marine intrusion into lower-salinity environments. The ensuing phase of freshwater flooding and fluvial sedimentation is represented by a distinct flood deposit in only three cores, but is absent or indistinct in most cores. The elusiveness of the Harvey fluvial flood deposit can be explained by the relatively low discharge and suspended sediment load of the San Bernard River, the uneven distribution of this event deposit, and its indistinctiveness with the underlying deposits laid down by previous flood events. [ABSTRACT FROM AUTHOR]

This paper begins with a study on the dual representations of risk and regret measures and their impact on modeling multistage decision making under uncertainty. A relationship between risk envelopes and regret envelopes is established by using the Lagrangian duality theory. Such a relationship opens a door to a decomposition scheme, called progressive hedging, for solving multistage risk minimization and regret minimization problems. In particular, the classical progressive hedging algorithm is modified in order to handle a new class of linkage constraints that arises from reformulations and other applications of risk and regret minimization problems. Numerical results are provided to show the efficiency of the progressive hedging algorithms. [ABSTRACT FROM AUTHOR]

We apply a novel method to estimate the magnitude of the 23 January 2018 M7.9 Alaska earth-quake using seismic stations recorded at local to regional distances in Alaska, US. We determine the source duration from back-projection results derived from the Alaska stations in a relatively compact azimuth range. Then we calculate the maximum P-wave displacements recorded on a wide azimuth range at distances of 8 to 15 degrees. Combining the source duration and the maximum P-wave displacements, we obtain magnitudes of 7.86–8.03 for the 23 January 2018 earthquake in 3–5 min, very close to the Mw 7.9 determined by the USGS and GCMT. This example validates the new approach for determining magnitude of large earthquakes using local to regional stations, and its time efficiency that magnitudes of large earthquakes can be accurately estimated within in 3–5 min after origin time. Therefore, further application of this new method would help accurate estimation of size of earthquakes that occur off shore and might cause tsunami hazards. [ABSTRACT FROM AUTHOR]

The Holocene hydrological regime on the Heixiazi Island is critical for understanding the evolution of the East Asian summer monsoon (EASM) for the island's climate-sensitive location on the northern fringe of the EASM domain. In this paper, a marsh depression on the central island was selected to reconstruct the locally hydrological variation and to discuss its indications for the Holocene EASM evolution. This work is based on multi-proxy (magnetic susceptibility, grain size, loss-on-ignition, and carbonate content) analyses of 22 modern sedimentary samples with a water-level gradient of 0–66 cm and 100 cored sedimentary samples covering last ~ 9.0 ka BP. The proxies' hydrological significance was previously interpreted by the 22 modern samples using linear regression equations to construct their relationships to water-level changes. Among these proxies, the magnetic susceptibility, carbonate content, as well as the Md and sand fraction of grain size exhibit high-level relationships against the water-level changes with R2 > 0.6. Thus, these four proxies' linear-regression equations were selected and used on the 100 cored samples, and the Holocene water-level changes in the studied depression were quantitatively reconstructed. It shows that two relatively high water-level stages with strengthened EASM occurred during 8.0–4.5 ka BP and 3.0–1.4 ka BP, which were alternated by three low water-level stages with declined EASM during ~ 9.0–8.0 ka BP, 4.5–3.0 ka BP, and 1.4–0 ka BP, respectively. Among these fluctuations, the highest water-level stage with most strengthened EASM which is defined as the Holocene Monsoon Maximum occurred during 6.4–4.5 ka BP. Such a new evolution pattern of the EASM can be further supported by a large variety of records from monsoon-margin regions. We suggest the Holocene EASM evolution was generally associated with the thermal conditions in both the inner Eurasia landmass and the West Pacific Ocean, with an exception of the weak EASM before 8.0 ka BP due to the enhanced Siberia High with the dominance of the Eurasia ice sheet in the early Holocene. [ABSTRACT FROM AUTHOR]

To evaluate the clinical outcome of deep hypothermic preservation of autologous skin in the treatment of large-area skin avulsion. Medium or full thickness-skin slices were harvested from large avulsion flaps between July and November 2017. They were stored in liquid nitrogen by vitrification. After the patient's condition became stable and the growth of the wound granulation tissue was satisfactory, the frozen skin slices were reheated quickly and replanted to the wound. Autologous skin that had been kept by deep cryopreservation had a high survival rate when grafted. It did not create new trauma or bring additional pain to patients. Yet it could shorten the course of treatment and reduce the medical cost for patients. It is an effective and economical way to treat large-area skin avulsion. [ABSTRACT FROM AUTHOR]

Background: PEG-rhG-CSF reduces neutropenia and improves chemotherapy safety. In China’s registration trial (CFDA: 2006L01305), we assessed its efficacy and safety against rhG-CSF, and prospectively explored its value over multiple cycles of chemotherapy.Methods: In this open-label, randomized, multicenter phase 3 study, breast cancer patients (n = 569) were randomized to receive PEG-rhG-CSF 100 µg/kg, PEG-rhG-CSF 6 mg, or rhG-CSF 5 µg/kg/d after chemotherapy. The primary endpoints were the incidence and duration of grade 3/4 neutropenia during cycle 1. Secondary endpoints included the incidence and duration of grade 3/4 neutropenia during cycles 2-4, the incidence of febrile neutropenia, and the safety.Results: A once-per-cycle PEG-rhG-CSF at either 100 µg/kg or 6 mg was not different from daily injections of rhG-CSF for either incidence or duration of grade 3/4 neutropenia. Interestingly, a substantial difference was noted during cycle 2, and the difference became bigger over cycles 3-4, reaching a statistical significance at cycle 4 in either incidence (P = 0.0309) or duration (P = 0.0289) favoring PEG-rhG-CSF. A significant trend toward a lower incidence of all-grade adverse events was noted at 129 (68.98%), 142 (75.53%), and 160 (82.47%) in the PEG-rhG-CSF 100 µg/kg and 6 mg and rhG-CSF groups, respectively (P = 0.0085). The corresponding incidence of grade 3/4 drug-related adverse events was 2/187 (1.07%), 1/188 (0.53%), and 8/194 (4.12%), respectively (P = 0.0477). Additionally, PFS in metastatic patients preferred PEG-rhG-CSF to rhG-CSF despite no significance observed by Kaplan-Meier analysis (n = 49, P = 0.153).Conclusions: PEG-rhG-CSF is a more convenient and safe formulation and a more effective prophylactic measure in breast cancer patients receiving multiple cycles of chemotherapy. [ABSTRACT FROM AUTHOR]

A classical result in risk measure theory states that every coherent risk measure has a dual representation as the supremum of certain expected value over a risk envelope. We study this topic in more detail. The related issues include: (1) Set operations of risk envelopes and how they change the risk measures, (2) The structure of risk envelopes of popular risk measures, (3) Aversity of risk measures and its impact to risk envelopes, and (4) A connection between risk measures in stochastic optimization and uncertainty sets in robust optimization. [ABSTRACT FROM AUTHOR]

CeZrO was prepared by co-precipitation method and a series of MnCo/CeZrO catalysts with different Mn/Co molar ratio were synthesized via the co-impregnation method. These catalysts were applied for gaseous toluene oxidation, which showed that the catalytic activity was significantly improved by the addition of Mn and Co. In particular, Mn-Co(1:1)/CeZrO with Mn/Co molar ratio of 1:1 displayed the best result with the lowest complete conversion temperature of 242 °C under a GHSV of 12,000 h. The as-prepared catalysts were characterized by X-ray diffraction, H temperature-programmed reduction, N adsorption-desorption, X-ray photoelectron spectroscopy and O temperature-programmed desorption. These characteristics revealed that the coexistence of Mn and Co could enhance the redox property and generate more surface adsorbed oxygen, thereby improving the performance of the catalysts for toluene low-temperature oxidation. The Mn-Co(1:1)/CeZrO exhibited the best catalytic activity and high stability. The excellent catalytic activity of the Mn-Co(1:1)/CeZrO could be ascribed to a greater amount of surface adsorbed oxygen species and Mn on the catalyst surface. [ABSTRACT FROM AUTHOR]

Determination of the influence and mechanism of metallic materials on SF decomposition under direct current (DC) partial discharge is one of the key aspects to improve SF decomposition component analysis (DCA). In this study, three kinds of metallic materials, namely, aluminum, copper, and 18/8 stainless steel, were made into needle-plate electrons, and then used in the SF positive DC partial discharge decomposition experiments. The influences of metallic materials on the five main decomposition components (i.e., CF, CO, SOF, SOF, and SO) were determined by gas chromatography-mass spectrometry. Results showed no significant correlation among the contents of CO for the different kinds of metallic materials. However, the metallic materials considerably influenced the contents of the other four gases. The difference in SF decomposition characteristics for the different metal electrodes was mainly due to the difference in anti-halogenation ability of metals and the passive film. Therefore, the impacts of different metallic materials should be considered when using SF DCA for the condition monitoring and fault diagnosis of DC gas-insulated equipment. [ABSTRACT FROM AUTHOR]

A ceramic coating containing Cu element was prepared on Ti6Al4V alloy using micro-arc oxidation (MAO) technology. After copper ions were added to the electrolyte solution of aluminate salt, the anode voltage in MAO process reduces, and the micropore size on the surface of the ceramic coating is more uniform. The crystalline phases of the ceramic coatings prepared in the electrolyte solutions with and without copper ions are mainly Ti element, rutile TiO, and anatase TiO. The addition of copper ions to the electrolyte solution makes rutile TiO content decrease but promotes the formation of AlTiO phase. Energy spectrum test results confirm that by adding copper ions to the electrolyte solution, the ceramic coating formed in the process of MAO contains copper element. [ABSTRACT FROM AUTHOR]

A series of oxidation experiments were carried out on these novel γ/γ′-strengthened cobalt-based alloys of the systems Co–9Al–10W and Co–9Al–10W–0.02X (X = La, Ce, Dy, Y) at 900 °C. The appropriate amounts’ addition of rare earth elements leads to improved oxidation properties at 900 °C, especially La elements show the best oxidation resistance (129.008 mg/cm2). However, the base Co–9Al–10W alloy shows the worst oxidation performance (151.544 mg/cm2). Multilayer oxide layers formed during the oxidation process, the outer were mainly CoO and Co3O4 oxides, and the middle layer contained complex oxides (containing Co, Al, and W). The inner layer consists of little discontinuous oxides, included few Al2O3 oxides. There existed a different crack width and the base alloy had the widest crack. Moreover, there exists a phase transformation (γ/γ′ to γ/Co3W) at the interface between oxide film and substrate. [ABSTRACT FROM PUBLISHER]

Phase stability, elastic, and thermodynamic properties of (Co,Ni)3(Al,Mo,Nb) with the L12 structure have been investigated by first-principles calculations. Calculated phonon density of states show that (Co,Ni)3(Al,Mo,Nb) is dynamically stable, and calculated elastic constants indicate that (Co,Ni)3(Al,Mo,Nb) possesses intrinsic ductility. Young’s and shear moduli of the simulated polycrystalline (Co,Ni)3(Al,Mo,Nb) phase are calculated using the Voigt–Reuss–Hill approach and are found to be smaller than those of Co3(Al,W). Calculated electronic density of states depicts covalent-like bonding existing in (Co,Ni)3(Al,Mo,Nb). Temperature-dependent thermodynamic properties of (Co,Ni)3(Al,Mo,Nb) can be described satisfactorily using the Debye–Grüneisen approach, including heat capacity, entropy, enthalpy, and linear thermal expansion coefficient. Predicted heat capacity, entropy, and linear thermal expansion coefficient of (Co,Ni)3(Al,Mo,Nb) show significant change as a function of temperature. Furthermore the obtained data can be used in the modeling of thermodynamic and mechanical properties of Co-based alloys to enable the design of high temperature alloys. [ABSTRACT FROM PUBLISHER]

As an important issue in image processing and computer vision, online visual tracking acts a critical role in numerous lines of research and has many potential applications. This paper presents a novel tracking algorithm based on subspace representation with continuous occlusion handling, the contributions of which are threefolds. First, this paper develops an effective objective function to represent the tracked object, in which the object reconstruction, the sparsity of the error term and the spatial consistency of the error term are simultaneously considered. Then, we derive an iterative algorithm to solve the proposed objective function based on the accelerated proximal gradient framework, and therefore obtain the optimal representation coefficients and the possible occlusion conditions. Finally, based on the proposed representation model, we design an effective likelihood function and a simple model update scheme for building a robust tracker within the particle filter framework. We conduct many experiments to evaluate the proposed tracking algorithm in comparisons with other state-of-the-art trackers. Both qualitative and quantitative evaluations demonstrate the proposed tracker achieves good performance. [ABSTRACT FROM AUTHOR]

Tackling the problems of underground water storage in collieries in arid regions requires knowledge of the effect of water intrusion and loading rate on the mechanical properties of and crack development in coal-rock combinations. Fifty-four coal-rock combinations were prepared and split equally into groups containing different moisture contents (dry, natural moisture and saturated) to conduct acoustic emission testing under uniaxial compression with loading rates ranging from 0.1 mm/min to 0.6 mm/min. The results show that the peak stress and strength-softening modulus, elastic modulus, strain-softening modulus, and post-peak modulus partly decrease with increasing moisture content and loading rate. In contrast, peak strain increases with increasing moisture content and fluctuates with rising loading rate. More significantly, the relationship between stiffness and stress, combined with accumulated counts of acoustic emission, can be used to precisely predict all phases of crack propagation. This is helpful in studying the impact of moisture content and loading rate on crack propagation and accurately calculating mechanical properties. We also determined that the stress thresholds of crack closure, crack initiation, and crack damage do not vary with changes of moisture content and loading rate, constituting 15.22%, 32.20%, and 80.98% of peak stress, respectively. These outcomes assist in developing approaches to water storage in coal mines, determining the necessary width of waterproof coal-rock pillars, and methods of supporting water-enriched roadways, while also advances understanding the mechanical properties of coal-rock combinations and laws of crack propagation. [ABSTRACT FROM AUTHOR]

Ovarian cancer is the most lethal gynecologic malignancy among women and usually initiated by the malignant transformation of epithelial cells. The progression of ovarian cancer involves a cascade of events, including tumor cell epithelial–mesenchymal transition (EMT), invasion, migration, and angiogenesis. Slug plays vital roles in the development of motile and invasive manner of cancer cells via EMT progression. The present work is devoted to investigate the effect of slug on the invasion and angiogenesis in ovarian cancer. The findings reveal that tumors with high expression of slug (44 of 60) represent higher tumor grade, lymph node metastasis, and worse prognosis than those with low expression (16 of 60; P < .05). We also identified a significant correlation between the slug and the microvessel density (MVD). Results of transwell migration assay showed that decreased slug induced by short hairpin RNA contributed to the repressed invasion and migration of SKOV3 cells. Additionally, the migration and tube formation capacity of human umbilical vein endothelial cells were markedly decreased in SKOV3-sh-conditioned medium compared to SKOV3 and SKOV3-NC. Furthermore, xenograft mouse models (SKOV3/SKOV3-sh cells injection into BALB/c nude mice) were developed to validate the effects of slug. The data confirmed that inhibited expression of slug extensively decreased the growth of tumor and MVD in vivo. Moreover, knockdown of slug can significantly reduce tumor angiogenesis of SKOV3 cells via ccn1/vascular endothelial growth factor. Thus, our present study demonstrates that slug is closely associated with tumor metastasis and angiogenesis in ovarian cancer. [ABSTRACT FROM AUTHOR]

The isothermal oxidation experiments were carried out on several new γ/γ′-strengthened cobalt-base alloys Co–Al–W–4Cr–0.02X (X = La, Ce, Dy, Y) at 900 and 800 °C. Due to an appropriate content of additional elements, the change in the morphology occurred and it significantly improved the oxidation resistance compared with those without Cr, among which the one with La elements shows the best oxidation resistance. Multiple oxide layers are also formed during the oxidation process, with CoWO4 and CoAl2O4 phases in the outer layer, and Cr, Al, W, and Co (e.g., Cr2O3) in the middle layer. The inner layer consists of some Al2O3 oxides, while more protective Al2O3 oxide was formed, esp. at the temperature of 800 °C. Both Cr2O3 and Al2O3 oxides were effectively protective oxides, which can prevent the intrusion of oxygen into the alloy substrate. Moreover, a phase transformation (γ/γ′ to γ/Co3W) was observed at the interface between oxide layer and substrate. [ABSTRACT FROM PUBLISHER]