Search

Long-period comets C/2019 L3 (ATLAS) and C/2020 P3 (ATLAS) remain active at heliocentric distance greater than 4 au. Broad-band Charge-Coupled Device (CCD) photometry of long-period comets C/2019 L3 and C/2020 P3 is analysed in this paper. The observation was obtained with three telescopes: ZEISS-1000 at Simeiz Observatory, Maksutov at Abastumani Astrophysical Observatory, and ZTSh at Crimean Astrophysical Observatory. The R -band A (0) f ρ values of C/2019 L3 range from (5043 ± 244) to (13611 ± 1874) cm, and tend to decrease first and then increase. The average colour indices of C/2019 L3 are B – V = 0.75 ± 0.06, V – R = 0.28 ± 0.05, and R – I = 0.21 ± 0.05. The reddening of C/2019 L3 exhibits variations during the observational runs, ranging from (13.75 ± 1.07) to (−15.69 ± 0.37) per cent/kÅ with an average value of (0.94 ± 0.23) per cent/kÅ. It possesses a non-steady coma since the average gradient of its surface brightness profile is −1.60. For comet C/2020 P3, its R -band A (0) f ρ values range from (606 ± 31) to (869 ± 20) cm, the colour indices are B–V = 1.04 ± 0.09, V–R = 0.26 ± 0.05, and R – I = 0.76 ± 0.04, and the reddening is (−6.65 ± 0.01) per cent/kÅ. The colour indices of the two comets differ from those of other long-period comets. Compared with other long-period comets, comet C/2019 L3 is very active at heliocentric distance of ∼4 au, while C/2020 P3 is moderately active at heliocentric distance of ∼7 au. [ABSTRACT FROM AUTHOR]

As a key factor affecting the performance of supercapacitors, the research on electrode materials for supercapacitors has been primarily focused on the cathode with little work found on anode materials. This has hindered the improvement of the energy density of supercapacitors. The objective of this work, therefore, was to prepare a high-performance, low-cost anode material for supercapacitors. Fe3O4 was synthesized by a hydrothermal method and Fe3O4/rGO nanocomposites were prepared by further hydrothermal treatment of Fe3O4 with graphene oxide. The Fe3O4/rGO nanocomposites were characterized by XRD, SEM, TEM, BET. and other methods to analyze their micromorphology and elemental composition. Electrochemical measurements were performed to assess the electrochemical properties of Fe3O4/rGO, which was tested with a high specific capacitance of 571.2 F g−1 (1 A g−1), much higher than that of pure Fe3O4 (214.7 F g−1). Assembling Fe3O4/rGO//MnO2 asymmetric supercapacitors (ASC) with MnO2 as the positive electrode and Fe3O4/rGO as the negative electrode, the device obtained an energy density of 95.1 Wh kg−1 at a power density of 2881 W kg−1. After 10,000 cycles at 10 A g−1, the ASC retained 87.2% of its original capacitance, so the Fe3O4/rGO nanocomposite could be an ideal anode material for high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

Although there have been many studies on asymmetric supercapacitors (ASCs), anode materials are still mainly carbon-based. However, carbon-based materials with low specific capacitance cannot match the cathode materials, limiting the energy density of ASCs. In this research, a low-cost and environmentally friendly anode of homogeneous α-Fe2O3 nanoparticles grown on three-dimensional graphene (3DG) hydrogel is synthesized, with significant specific capacitance (788.6 F g−1 at 1 A g−1) and exceptionally good stability (retaining 82.3% capacitance after 5000 cycles). The composite material of NiCo2O4 nanorods grown on 3DG (NiCo2O4/3DG) has been prepared as the cathode by a similar method. The NiCo2O4/3DG also shows excellent electrochemical performance (1264.3 F g−1 at 1 A g−1 and stability of 91.7% after 5000 cycles). Furthermore, the ASCs of NiCo2O4/3DG//α-Fe2O3/3DG, which is composed of the as-prepared cathode and anode materials, exhibits excellent energy density of 77.8 W h kg−1 at a power density of 800 W kg−1, and outstanding stability of 81.6% after 5000 cycles at 10 A g−1. Therefore, this proves that α-Fe2O3/3DG is a promising anode material for supercapacitors. [ABSTRACT FROM AUTHOR]

Both EGFR and VEGFR-2 play a critical role in tumor growth, angiogenesis and metastasis, and targeting EGFR and VEGFR-2 simultaneously represents a promising approach to cancer treatment. In this work, a series of novel quinazoline- and thiourea-containing sorafenib analogs (10a-v) were designed and synthesized as EGFR and VEGFR-2 dual TK inhibitors. Their in vitro enzymatic inhibitory activities against EGFR and VEGFR-2, and antiproliferative activities against HCT-116, MCF-7 and B16 cell lines were evaluated and described. Most of the compounds showed potent activities against both cell lines and TK kinases. Compounds 10b and 10q which exhibited the most potent inhibitory activities against EGFR (IC50 = 0.02 µM and 0.01 µM, respectively), VEGFR-2 (IC50 = 0.05 µM and 0.08 µM, respectively), and good antiproliferative activities, also displayed competitive anti-tumor activities than sorafenib in vivo by B16 melanoma xenograft model test. [ABSTRACT FROM AUTHOR]

This study investigates the frequency and injury severity of pedestrian crashes across Texas using tree-based machine learning models. Ten years of police records are used along with roadway inventory and other sources to map 78,000 + pedestrian crashes over 700,000 road segments. Methods like random forests (RF), gradient boosting (LightGBM and XGBoost), and Bayesian additive regression trees (XBART) are applied and compared. The crash frequency models indicate that highway design variables have significant impacts on crash frequencies. Severity models show how higher speed limits significantly increase the likelihood of pedestrian fatalities and severe injuries, and how intoxication (of drivers or pedestrians) lead to more severe injuries. The 4 specifications perform similarly in predicting crash counts, with LightGBM having much faster computing times. Across the crash-severity models, XBART achieved greater precision values but with significantly higher computating times. [ABSTRACT FROM AUTHOR]

Bearings play a key role in rolling mills, and the uniformity of their lubricant film directly affects the degree of wear of bearings and the safety of equipment. Due to long-term stress, the lubricant film inside the bearing is not uniformly distributed, resulting in uneven wear between the journal and the shaft tile, which increases the potential safety hazards in production. Traditional disassembly inspection methods are complex and time-consuming. Ultrasonic nondestructive testing technology, which has the advantages of nondestructive and adaptable, has become an effective means of assessing the thickness of the oil film in bearings. In this study, an experimental platform for calibrating the lubricant film thickness in bearings was constructed for the first time, and the acoustic characteristics of different thicknesses of the oil film were measured using ultrasonic detection equipment to verify the accuracy of the simulation process. The experimental results show that after discrete Fourier transform processing, the main features of the frequency channels of the reflected acoustic signals of different thicknesses of the oil film are consistent with the finite element simulation results, and the errors of the oil film thicknesses calculated from the reflection coefficients are within 10% of the set thicknesses, and the measurement ranges cover from 5 μm to 250 μm. Therefore, the above method can realize the accurate measurement of the thicknesses of the oil film in bearings. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office 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.)

Rolling mill bearings are prone to wear, erosion, and other damage characteristics due to prolonged exposure to rolling forces. Therefore, regular inspection of rolling mill bearings is necessary. Ultrasonic technology, due to its non-destructive nature, allows for measuring the oil film thickness distribution within the bearing during disassembly. However, during the process of using ultrasonic reflection coefficients to determine the oil film thickness and distribution state of rolling mill bearings, changes in bearing temperature due to prolonged operation can occur. Ultrasonic waves are susceptible to temperature variations, and different temperatures of the measured structure can lead to changes in measurement results, ultimately distorting the results. This paper proposes using density and sound speed compensation methods to address this issue. It simulates and analyzes the oil film reflection coefficients at different temperatures, ultimately confirming the feasibility and effectiveness of this approach. The paper establishes a functional relationship between bearing pressure and reflection coefficients, oil film thickness, and reflection coefficients. This allows for the compensation of reflection coefficients under any pressure conditions, enhancing the accuracy of oil film thickness detection. The proposed method provides technical support for the maintenance of plate rolling processes in the steel industry. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office 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.)

This article analyzes the appropriate types of water rights systems for different regions with varying water resource conditions in China. The most appropriate water rights systems for various zones were determined by comparing the value of influencing factors with corresponding thresholds in China's second-class zones of water resources. It is shown that a riparian rights system under water withdrawals permission could be adopted in most regions of southern China. For most northern Chinese regions, the quantity proportional water rights systems should be adopted and further improved. In contrast to the implementation of a single quantity proportional water rights system, this paper innovatively proposes a zoning scheme for China's water rights system. The appropriate type of water rights system can be identified according to the region's specific water resource conditions. It can provide a scientific reference for the reform of water rights systems in China and other countries or regions. [ABSTRACT FROM AUTHOR]

High ground stress soft rock is a common adverse geology in the process of tunnel construction in western mountainous areas of China. This type of stratum is highly susceptible to large deformation disasters during tunnel construction due to the combined effects of higher ground stress and special surrounding rock mechanical properties. The treating ideas and methods for large deformation of tunnel in China and abroad are summarized. Based on the deformation section of the Shengli Village tunnel of the Leshan-Hanyuan expressway, the causes of large deformation are analyzed according to the characteristics of structural deformation, geological conditions, and monitoring data, and the principles and specific countermeasures for large extrusion deformation in steep rock strata in the Shengli Village tunnel are proposed. The results reveal the following: (1) The large deformation of the Shengli Village tunnel is mainly caused by the joint action of structural stress, weak fracture of surrounding rock, rock dip angle, tunnel trend, and groundwater. (2) The deformation and failure of the steep rock strata exhibit obvious asymmetry and non-uniformity, the bending and inner bulge are easy to occur at the arch, the horizontal convergence is significantly greater than the arch roof settlement, and shows long-term creep characteristics. (3) According to the large deformation treatment idea of "combination of relaxation and resistance", the measures of " one-time excavation, multiple-time support, releasing deformation, strengthening surrounding rock, and strengthening structure" have achieved good control effect on the deformation of surrounding rock. [ABSTRACT FROM AUTHOR]

Energy is an essential topic owing to the severe environmental problems faced worldwide, especially in underdeveloped rural areas. Energy literacy is closely related to energy consumption and conservation behaviors in daily life. Although the energy attitudes and behaviors of communities can determine the sustainable development of rural tourism, less attention has been paid to the energy literacy of rural communities. This study adopted a measurable scale to compare the energy literacy levels between 188 questionnaires from rural residents in tourism communities and 195 questionnaires from non-tourism communities both in the Jizhou District, China. A theoretical model was constructed to investigate the relationships between the variables. Additionally, this study verified the influence of rural tourism activities on communities' energy literacy by comparing different villages. The results showed that rural communities have high levels of energy literacy in the knowledge, attitude, and behavioral sectors. Positive relationships between knowledge and attitude and between attitudes and behaviors were estimated. However, the positive impact of knowledge on behavior was inconspicuous. The most important theoretical contribution of this study is the confirmation of the significant differences in energy literacy between traditional and rural tourism destination communities, thus proving the improvement in communities' energy literacy induced by tourism development. Finally, this study presents practical implications for policymakers. [ABSTRACT FROM AUTHOR]

This paper analyzes the classification and the hierarchical structure of water rights systems. Based on the water rights meta types which are the most basic elements of water rights system, the unit water rights systems and mixed water rights systems have been further determined. The unit water rights systems which are composed of water rights meta types are the smallest units that exist independently and maintain the characteristics of water rights systems. While the mixed water rights systems are the mixed mosaic of different unit systems. The unit water rights systems are chosen as research units because of their independence. Through collecting the data of objective influencing factors in research units and statistical analysis of these data, the threshold of all influencing factors for each unit water rights system have been estimated. Meanwhile, the applicable conditions of each unit water rights systems can be determined based on these thresholds. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office 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.)

Coal-burning type of arsenism, a chronic arsenism caused by environmental arsenic pollution, found firstly at Guizhou Province of China, manifested as the disruption of pro- and anti-inflammatory T cell balance and multiple organ damage, while no specific treatment for the arsenism patients. The effect of methylation of the forkhead box P3 (Foxp3) promoter region on arsenic-induced disruption of pro- and anti-inflammatory T cell balance was first evaluated in this study, between the control and arsenism groups. The results show that arsenic can induce the hypermethylation of 6 sites in the Foxp3 promoter by upregulating the expression of recombinant DNA Methyltransferase 1 (Dnmt1) mRNA, leading to the downregulation of Foxp3 mRNA, Tregs, and interleukin 10 (IL-10, anti-inflammatory cytokine) levels, and increased the levels of interleukin 17 (IL-17, pro-inflammatory cytokine) in the peripheral blood of patients with arsenic poisoning. Further randomized controlled double-blind experiments (including the placebo control groups and the Ginkgo biloba extract (GBE) intervention groups) showed that compared to the placebo control group or before GBE intervention, the levels of Dnmt1 mRNA, Foxp3 methylation, and IL-17 in the peripheral blood of the GBE intervention group were significantly decreased after intervention (P < 0.05), but the levels of regulatory T cells (Tregs) and IL-10 were significantly increased (P < 0.05). Our study provides some limited evidence that GBE can attenuate the disruption of pro- and anti-inflammatory balance of peripheral blood in arsenism patients by decreasing hypermethylation of the Foxp3 promoter region. This study provides scientific basis for further understanding a possible natural medicinal plant, GBE, as a more effective measure to prevent and control the disruption of pro- and anti-inflammatory balance caused by coal-burning type of arsenism. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office 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.)

Background: Overcrowding, abuse of antibiotics and increasing antimicrobial resistance negatively affect neonatal survival rates in developing countries. We aimed to define pathogens and their antimicrobial resistance (AMR) of early-onset sepsis (EOS), hospital-acquired late-onset sepsis (HALOS) and community-acquired late-onset sepsis (CALOS) in 25 neonatal intensive care units (NICUs) in China. Study design: This retrospective descriptive study included pathogens and their AMR from all neonates with bloodstream infections (BSIs) admitted to 25 tertiary hospitals in China from January 1, 2017, and December 31, 2019. We defined EOS as the occurrence of BSI at or before 72 h of life and late-onset sepsis (LOS) if BSI occurred after 72 h of life. LOS were classified as CALOS if occurrence of BSI was ≤ 48 h after admission, and HALOS, if occurrence was > 48 h after admission. Results: We identified 1092 pathogens of BSIs in 1088 infants from 25 NICUs. Thirty-two percent of all pathogens were responsible for EOS, 64.3% HALOS, and 3.7% CALOS. Gram-negative (GN) bacteria accounted for a majority of pathogens in EOS (56.7%) and HALOS (62.2%). The most frequent pathogens causing EOS were Escherichia coli (27.2%) and group B streptococcus (GBS; 14.6%) whereas in CALOS they were GBS (46.3%) and Staphylococcus aureus (41.5%). Klebsiella pneumoniae (27.9%), Escherichia coli (15.7%) and Fungi (12.8%) were the top three isolates in HALOS. Third-generation cephalosporin resistance rates in GN bacteria ranged from 9.7 to 55.6% in EOS and 26% to 63.3% in HALOS. Carbapenem resistance rates in GN bacteria ranged from 2.7 to 31.3% in HALOS and only six isolates in EOS were carbapenem resistant. High rates of multidrug resistance were observed in Klebsiella pneumoniae (60.7%) in HALOS and in Escherichia coli (44.4%) in EOS. All gram-positive bacteria were susceptible to vancomycin except for three Enterococcus faecalis in HALOS. All-cause mortality was higher among neonates with EOS than HALOS (7.4% VS 4.4%, [OR] 0.577, 95% CI 0.337–0.989; P = 0.045). Conclusions: Escherichia coli, Klebsiella pneumoniae and GBS were the leading pathogens in EOS, HALOS and CALOS, respectively. The high proportion of pathogens and high degree of antimicrobial resistance in HALOS underscore understanding of the pathogenesis and emphasise the need to devise effective interventions in developing countries. [ABSTRACT FROM AUTHOR]