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Mountainous river bars are natural shoals formed in rivers as a result of bank slumping, undercutting, and sediment deposition. We investigated total phosphorus (TP) and available phosphorus (P) spatial variation in soil, factors influencing soil P spatial variation, and the environmental buffering capacity of mountainous river bars. Soil samples were collected at the head, middle, and tail transects of nine bars. Soil TP and available P contents ranged as 357.5–1256.48 mg kg-1 and 5.02–45.79 mg kg-1, respectively. Soil TP content was at a low level in the study area, whereas soil available P content was at a high level in some bars. Soil TP exhibited an increasing trend from head to tail transects in bars, but a decreasing trend was observed from upper to lower reaches, influenced by location of bars in the river, location of soil in the bar and soil texture. Soil available P showed an increasing trend from head to tail transects in bars and a fluctuation variation trend from upper to lower reaches, influenced by land use and vegetation biomass. The environmental buffering capacity of the bar is the capacity of bar to intercept P migrate from soil to river. Bars in lower reach, with lower height above water surface and narrower width could lead to weaker environmental buffering capacity in mountainous rivers, so more attention should be paid to these bars in order to reduce P pollution effectively. [ABSTRACT FROM AUTHOR]

Considering the changing characteristics of the mechanical properties of rock-soil with depth, it is assumed that the shear stiffness and ultimate shear stress of the rock-soil around the vertical grouting anchor increase exponentially with depth. At the same time, based on the assumption that the shear stiffness in the plastic deformation zone decreases exponentially from the depth of the plastic deformation zone to the top of the anchor, the pull-out mechanical behavior of the vertical grouting anchor is theoretically analyzed. Through engineering case analysis, the rationality and accuracy of the hypothetical model in this paper are verified. And on this basis, the influence of the depth variation coefficient on the shear stress distribution of the anchor was further analyzed. The results of the study show some of the following conclusions. (i) If the mechanical properties of the rock-soil around the anchor increase with depth are not considered, the ultimate pull-out force of the anchor may be underestimated, resulting in unnecessary waste; (ii) the depth variation coefficient has a great influence on the shear stress distribution form of the anchor; (iii) considering the characteristics of the mechanical properties of rock-soil as the depth increases is beneficial to improve the working behavior of the anchor, and can more truly reflect the load transfer process of the anchor. Reasonable consideration should be given in the design and calculation of the vertical grouted anchor. [ABSTRACT FROM AUTHOR]

Based on the idea of discretization and the force balance analysis of each mass spring element, a spring-element analysis method for bolt is proposed. By analyzing the mechanical behavior of the bond interface of the fully grouted bolt, three coupling models of the bond interface, the slider model, the spring model and the spring-slider model, are proposed. Using the spring-element method, five load transfer models, namely the slider model, the spring model, the modified spring model, the spring-pulled slider model, and the spring-slider model, were deduced. And get the bolt displacement distribution function, axial force distribution function and shear stress distribution function under each model. The five proposed models are verified, analyzed and discussed by using the pull-out test of the smooth steel bolt and the threaded steel bolt. It is verified by experiments that this study is helpful to comprehensively understand the mechanical behavior of fully grouted bolts under axial load. The proposed spring element analysis method is simple and easy to understand and the results are reasonable. [ABSTRACT FROM AUTHOR]

Chemoresistance limits its clinical implementation for pancreatic ductal adenocarcinoma (PDAC). We previously generated an EGFR/HER2 targeted conjugate, dual-targeting ligand-based lidamycin (DTLL), which shows a highly potent antitumor effect. To overcome chemoresistance in PDAC, we aim to study DTLL efficacy when combined with gemcitabine and explore its mechanisms of action. DTLL in combination with gemcitabine show a superior inhibitory effect on the growth of gemcitabine-resistant/sensitive tumors. DTLL sensitizes gemcitabine efficacy via distinct action mechanisms mediated by mothers against decapentaplegic homolog 4 (SMAD4). It not only prevents neoplastic proliferation via ATK/mTOR blockade and NF-κB impaired function in SMAD4-sufficient PDACs, but also restores SMAD4 bioactivity to trigger downstream NF-κB-regulated signaling in SMAD4-deficient tumors and to overcome chemoresistance. DTLL seems to act as a SMAD4 module that normalizes its function in PDAC, having a synergistic effect in combination with gemcitabine. Our findings provide insight into a rational SMAD4-directed precision therapy in PDAC. Chemoresistance is a main limitation for the treatment of pancreatic ductal adenocarcinoma (PDAC). Here, the authors show that an antibody drug conjugate-like compound targeting both EGFR and HER2 overcomes gemcitabine resistance in PDAC preclinical models by mechanisms involving the tumour suppressor SMAD4. [ABSTRACT FROM AUTHOR]

Storm surge, sea wave, sea ice, red tide and harmful marine creature bloom are main marine disasters occurring in the coast and offshore areas of Qingdao City, Shandong Province, China. Marine disasters mentioned above can be divided into five categories, namely, marine meteorological disasters, marine hydrological disasters, marine geological disasters, marine ecological disasters and man-made marine disasters. Over the past century, the marine disasters in the coast and offshore areas of Qingdao City have caused great economic losses and casualties. In recent years, some problems still exist in emergency management against marine disasters in Qingdao City, such as inaccurate predictions of disasters, untimely early warning and lack of social participation in the emergency management. On the basis of scenario analysis, the authors try to predict different possible scenarios of marine disasters at different early warning levels and propose some optimized emergency countermeasures against marine disaster in Qingdao City. Results of our research can provide a theoretical basis for the revision and improvement of emergency plans and thus guarantee timely and effective emergency management actions against marine disasters in Qingdao City. [ABSTRACT FROM AUTHOR]

This study describes an ultrasound-accelerated hollow-fiber liquid-phase microextraction (U-HF-LPME) method for the simultaneous trace analysis of benzene and toluene in beverages. Sample preparation was followed by analysis using gas chromatography-flame ionization detection. Experimental parameters such as extraction solvent, extraction time, ultrasonic power and frequency, extractant volume and ionic strength of the sample were assessed and optimized. Finally, the enrichment factor (EF), limit of quantitation (LOQ) and precision of the method for benzene and toluene were evaluated. The relative standard deviations (RSD, n = 5) were found to be 0.11 and 1.07% with good relative recovery of 98.2 and 99.6%, respectively. High EF of 105 and 308, and LOQ of 0.34 and 0.18 μg L were obtained within 10 min. The results demonstrated that the proposed method was suitable for trace analysis of beverage samples. [ABSTRACT FROM AUTHOR]

Mesocarbon microbeads (MCMB) with narrow size distribution, excellent sphericity and no obvious conglutination have been prepared with a coal tar pitch containing quinoline insolubles (QI) as the raw material. Optical microscopy and scanning electron microscopy (SEM) are used to examine the structure of the MCMB. It has been found that SEM technique shows the structural information of MCMB clearly in the form of micrographs even when the structure of MCMB is complex, while the optical technique is useful for analysis of the regular structure of the mesophase spheres but cannot be effectively used to analyze either the complex structure of the green MCMB or the structures of the further heat-treated ones at different temperatures. According to the characteristics of the carbon layers, the structures of the as-prepared MCMB in the present experiment could be classified as (1) Parallel Layer type structure and (2) Bent Layer type structure with the carbon layers gathering at one or two points in the MCMB. In the experiments, SEM is also utilized to investigate the structures of MCMB that are heat-treated at different temperatures. It has been found that the MCMB without any further heat-treatment show no layered-carbons, while the ones heat-treated at temperature higher than 1000C exhibit obvious layered carbons across their sections. When increasing the heat-treatment temperature, the carbon layers become thinner and flatter. [ABSTRACT FROM AUTHOR]