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Microtubule binding agents such as paclitaxel and vincristine have activity in metastatic melanoma. However, even responsive tumors develop resistance, highlighting the need to investigate new drug molecules. Here, we showed that a new compound, CH-2-102, developed by our group, has high anti-tumor efficacy in human and murine melanoma cells. We confirmed that CH-2-102 robustly suppresses the microtubule polymerization process by directly interacting with the colchicine binding site. Our results unveil that CH-2-102 suppresses microtubule polymerization and subsequently induces G2 phase cell arrest as one of the possible mechanisms. Notably, CH-2-102 maintains its efficacy even in the paclitaxel resistance melanoma cells due to different binding sites and a non-Pgp substrate. We developed a pH-responsive drug-polymer Schiff bases linker for high drug loading into nanoparticles (NPs). Our CH-2-102 conjugated NPs induced tumor regression more effectively than Abraxane® (Nab-paclitaxel, N-PTX), free drug, and non-sensitive NPs in B16-F10 cell-derived lung metastasis mouse model. Furthermore, our results suggest that the formulation has a high impact on the in vivo efficacy of the drug and warrants further investigation in other cancers, particularly taxane resistant. In conclusion, the microtubule polymerization inhibitor CH-2-102 conjugated pH-responsive NPs induce tumor regression in lung metastasis melanoma mice, suggesting it may be an effective strategy for treating metastatic melanoma.

The distal reach of the Lower Jingjiang River (LJR) in the middle of the Yangtze River consists of five adjacent bends, among which the Qigongling Bend is a Ω-shaped meander with a mean sinuosity of 2.2 and the narrowest neck 525 m in width. This bend is slowly approaching neck cutoff owing to progressive bank erosion. An abnormal phenomenon has occurred in this bend since the Three Gorges Reservoir (TGR) began to operate in 2003 which is erosion in the inner bank zone and deposition in the outer bank zone. This problem has not been fully understood because of the interplay of changes in water-sediment, bank erosion, and artificial bank revetment. In this study, aerial and remote sensing images, hydrological data, channel topography, and an existing bank erosion model are used to reveal channel morphodynamics of this bend and the trend of the potential neck cutoff induced by bank erosion. The study results show that the clear water released from the TGR has provided by forcefully eroded the point bar of inner bank but failed to scour the outer bank due to the protection of bank revetment since the 1990s. Thus far, the outer bank zone near the bend apex has increasingly widened in conjunction with the formation of 2 emerging sand bars. Consequently, the thalweg of the main channel has laterally shifted toward the inner bank by roughly 800 m. More severely, the rate of bank retreat on the upstream side of the bend neck was about 4.5 m/yr in 2010–2019, but the downstream side of this neck was experienced slight deposition. Bank erosion could be accelerated by progressively increasing erosion and eventually trigger the occurrence of neck cutoff in the next few decades, thereby significantly altering the quasi-equilibrium regime of channel morphodynamics in the LJR.

Retrogressive erosion is a high-speed erosion process that usually occurs during the rapid release of stored water in reservoirs built on sandy rivers. Retrogressive erosion has been utilized in the practice of reservoir sedimentation control, but accurate prediction of the bed deformation process by numerical models has rarely been reported. The current study presents a one-dimensional morphodynamic model for simulating the evolution process of retrogressive erosion induced by high-velocity flows on steep slopes. The governing equations apply a Cartesian coordinate system with a vertically oriented z axis. The bed surface gradient and friction terms in the flow equations include correction factors to take account of the effects of high slope on flow movement. The net vertical sediment flux term in the sediment transport and bed deformation equations is calculated using an equation of erosion velocity. Particularly, this equation is based on an empirical relation between the sediment entrainment rate and the Shields parameter in contrast to the traditional sediment transport capacity, and the critical Shields parameter is modified by taking into account the permeability of the sediment layer and the stability of particles on a slope. The feedback of scoured sediment on the flow movement is considered by additional terms in the governing equations. Flume experiments of retrogressive erosion in literature were simulated to validate the model. The temporal variations of the longitudinal profiles of the free surface and channel bed and the sediment transport rate were well predicted. The algorithm calculating sediment entrainment in the proposed model also was validated for an experiment measuring entrainment rate from the literature. More importantly, it was found that the morphodynamic model using the sediment transport capacity equation predicts the trend of cumulative erosion contrary to the measurements, while results of the proposed model can follow a similar trend with the observed data in the retrogressive erosion process.

Successful treatment of pancreatic cancer remains a challenge due to desmoplasia, development of chemoresistance, and systemic toxicity. Herein, we synthesized (6-(3-hydroxy-4-methoxylphenyl)pyridin-2-yl) (3,4,5-trimethoxyphenyl)methanone (CH-3-8), a novel microtubule polymerization inhibitor with little susceptible to transporter-mediated chemoresistance. CH-3-8 binding to the colchicine-binding site in tubulin protein was confirmed by tubulin polymerization assay and molecular modeling. CH-3-8 disrupted microtubule dynamics at the nanomolar concentration in MIA PaCa-2 and PANC-1 pancreatic cancer cell lines. CH-3-8 significantly inhibited the proliferation of these cells, induced G2/M cell cycle arrest, and led to apoptosis. CH-3-8 is hydrophobic with an aqueous solubility of 0.97 ± 0.16 μg/mL at pH 7.4. We further conjugated it with dodecanol through diglycolate linker to increase hydrophobicity and thus loading in lipid-based delivery systems. Hence, we encapsulated CH-3-8 lipid conjugate (LDC) into methoxy poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate-graft-dodecanol) (mPEG-b-PCC-g-DC) polymeric nanoparticles (NPs) by solvent evaporation, resulting in a mean particle size of 125.6 ± 2.3 nm and drug loading of 10 ± 1.0% (w/w) while the same polymer could only load 1.6 ± 0.4 (w/w) CH-3-8 using the same method. Systemic administration of 6 doses of CH-3-8 and LDC loaded NPs at the dose of 20 mg/kg into orthotopic pancreatic tumor-bearing NSG mice every alternate day resulted in significant tumor regression. Systemic toxicity was negligible, as evidenced by histological evaluations. In conclusion, CH-3-8 LDC loaded NPs have the potential to improve outcomes of pancreatic cancer by overcoming transporter-mediated chemoresistance and reducing systemic toxicity.

During the hydrogen filling process, the excessive temperature rise may cause the hydrogen storage tank to fail. Therefore, preventing the temperature from rising too high is an important guarantee for the safety of the hydrogen storage cylinder. The analytical solution of a single-zone thermodynamic model for hydrogen refueling is obtained. Based on the analytical solution of the final hydrogen temperature derived from the hydrogen filling theoretical model, the relationship among the final hydrogen temperature and the initial temperature and the inlet temperature and the ambient temperature is obtained. The model is used to achieve correlations coefficients among the above parameters. Data of Type III 40L tank and Type IV 29L tank used in the model are from the experiment, and data of Type III 25L tank and Type IV 174L tank are from the simulation. The results show that our analytical solution is applicable for determining correlations between final hydrogen temperature and refueling parameters from experimental and numerical data. Our analytical solution is more accurate than the reduced model reported in reference. At the same time, the effects of the initial temperature and the inlet temperature on the final temperature are stronger in Type IV tank than in the Type III tank. This study may provide guides for improving hydrogen refueling standards.

Strand displacement DNA synthesis is essential for DNA replication. Gp90, the sole DNA polymerase of Pseudomonas aeruginosa phage 1, can bypass multiply DNA lesions. However, whether it can perform strand displacement synthesis is still unknown. In this work, we found that gp90 exo- could perform strand displacement synthesis, albeit its activity and processivity were lower than those of primer extension. Gp90 exo- itself could not unwind Y-shaped or fork DNA. Tail and gap at DNA fork were necessary for efficient synthesis. High GC content obviously inhibited strand displacement synthesis. Consecutive GC sequence at the entrance of fork showed more inhibition effect on DNA synthesis than that in the downstream DNA fork. The fraction of productive polymerase and DNA complex (A values) was higher for fork than gap; while their average extension rates (kp values) were similar. However, both A and kp values were lower than those for the primer/template (P/T) substrate. The binding of gp90 exo- to fork was tighter than P/T or gap in the absence of dATP. In the presence of dATP to form ternary complex, the binding affinity of gp90 exo- to P/T or gap was increased compared with that in the binary complex. Abasic site, 8-oxoG, and O6-MeG inhibited and even blocked strand displacement synthesis. This work shows that gp90 exo- could perform strand displacement DNA synthesis at DNA fork, discovering the presence of new functions of PaP1 DNA polymerase in DNA replication and propagation of PaP1.

At the initial stage of dam operation in an alluvial river, significant vertical bed incision and transverse bank erosion processes always occur in the river reach downstream of the dam, with the latter being usually an integrated product of several interacting processes. A coupled two-dimensional (2D) model for the processes of bed evolution and bank erosion has been proposed in this study, which integrates a 2D morphodynamic module with a bank-erosion module and a groundwater flow module. In addition to the action of fluvial erosion, the effect of groundwater flow on bank erosion was considered, with the changes in pore water pressure and matrix suction being calculated. The proposed model was calibrated and validated through simulating channel evolution processes in a 30.54 km sub-reach of the Upper Jingjiang Reach of the Middle Yangtze River, with the effects of infiltration recharge on bank erosion and incoming flow on the central bar evolution being investigated. The results show that: (i) the proposed model had a good performance in reproducing flow and sediment factors, in terms of water depth, depth-averaged velocity and suspended sediment concentration, daily averaged discharge and river stage, and flow and sediment diversion ratios in local anabranching subreaches; (ii) the proposed model correctly calculated the bank erosion processes in the study reach, with the calculated bank retreat width being close to the measured value, however, it was not enough to fully reproduce the evolution of central bars, indicating that a specialized and improved module may be necessary for central bar evolution and its interaction with bank erosion; (iii) the groundwater level change lagged behind the river stage variation, and it showed a more obvious phase lag and a higher value at the same river stage (corresponding to a higher pore water pressure), when encountering with a more rapidly changing river stage; and (iv) the rate of infiltration recharge caused by rainfall process, would generally increase the groundwater level and thus the bank erosion degree in the study reach. In addition, the shifting of incoming main flow might take an obvious impact on the calculation of nearby central bar evolution.

In an alluvial river, various kinds of river regulation engineering are usually constructed along the reach for the stability of channel regime and the safety of flood control, which greatly affects the process of channel evolution. Therefore, a one-dimensional (1D) morphodynamic model has been improved to simulate the fluvial processes influenced by large-scale river regulation works. In the refined model, each node of a cross-section was labeled using a specified point code representing the zones of floodplain and main-channel with or without regulation engineering, and sediment transport and bed deformation in different zones were treated separately. In the zones without regulation engineering, both bed deposition and bed erosion were permitted to occur; in the zones with regulation works, bed deposition was allowed, while bed erosion was not permitted to occur owing to the restriction of those engineering, unless there was a deposition layer newly formed over the previous simulation period. Then the improved model was calibrated and verified using field observations through the application to a 347-km-long alluvial channel located in the Middle Yangtze River in China. The results for the year 2016 show that the channel scour volume without the effect of river regulation works was 9% greater than the measured value (34.43 × 106 t), while the outcome considering this effect (35.81 × 106 t) was in closer agreement with the measurements. Moreover, the variation in channel geometry obtained from the improved model agreed better with the observed data. River regulation works would limit the channel incision, and it is likely to scour the other unprotected bed of a cross-section or the downstream cross-sections as the flow cannot carry enough sediment from the protected bed. Simulated results indicate that part of the main-channel zone at the Jing65 section was protected, but the riverbed continued to incise by about 0.68 m in the protected area when the effect of bed-protection works was not considered in the model, which was not in accord with the observed channel geometry. Therefore, this effect of large-scale river regulation works on channel evolution needs to be considered for a higher simulation accuracy.

Recent significant channel evolution in the Jingjiang Reach has raised much attention, particularly the remarkable bank erosion. A coupled model for simulating bed deformation and bank erosion has been proposed in this study, which focuses on the erosion of the bank with a composite structure in the Lower Jingjiang Reach. In order to cover three contributing processes that may interact with each other, the proposed model integrates a one-dimensional morphodynamic module with a two-dimensional module of ground water flow and a bank erosion module for the cantilever failure of a composite riverbank. Model performance was evaluated through a detailed simulation of channel evolution along a 150.8-km subreach in the Jingjiang Reach over the 2005 hydrological year. Satisfying results were obtained from the simulation, showing relatively close agreement between the calculations and measurements in terms of hydrological data at the outlet section, bank erosion sites, longitudinal channel profile and typical cross-sectional profiles. In addition, investigations into temporal changes in bank soil properties and critical overhanging width at cantilever failure demonstrate that there was a seasonal variation in the volumetric water content of bank soil, which increased during the rising and flood periods and then decreased during the recession period, showing an impact on the occurrence timing of cantilever failures. The tensile strength and critical overhanging width had an inverse relationship with the water content, whereas the critical width sharply increased and then decreased during high flows affected by a rapid change in river stage. The temporal distribution of cantilever failure events indicates that cantilever failure primarily occurred in the flood and recession periods. The effects of bed roughness, water content variation and secondary flow on bank erosion were also discussed.

Background Coronavirus disease 2019 (COVID-19) has caused a global pandemic that has driven the widespread use of applications (apps) for outbreak management in China, but the characteristics and quality of these apps are currently unknown. Objective The first objective of this study was to investigate the functional characteristics of individual epidemic prevention and control apps in China, and the second objective was to evaluate the quality of these apps. Methods We searched the QimaiTM mobile application data analysis platform and the AladdinTM WeChat applet data analysis platform with keywords and quantified the search results based on the search index, relevance, and the Aladdin index to identify apps with high public popularity. The quality of the apps was rated by 2 independent raters using the Mobile App Rating Scale (MARS). The intraclass correlation coefficient (ICC) between raters was used as a measure of interrater reliability. Results All 20 of the included apps had acceptable quality. Functionality had the highest score, followed by information quality, aesthetics, and engagement. There were no significant differences between the independent apps and WeChat applets in app quality (t = 1.907, p = 0.073) and subjective quality (t = 0.899, p = 0.381). These apps were related to COVID-19 individual prevention and control, and the functional features that contributed to the quality of the apps were grouped into six categories, i.e., health self-checking and reporting, news about COVID-19, scientific publicity and education, telemedicine services, personal travel inquiries, and digital contact tracing. Conclusions Individual COVID-19 prevention and control apps in China were developed by adding epidemic prevention and control functions to existing social apps rather than independently developing apps. The overall quality of such apps was acceptable, but scores in the engagement section were generally low, especially for WeChat applets.

Upstream damming can greatly alter the flow and sediment conditions entering downstream reaches, leading to remarkable channel adjustments. Especially in a gravel-sand bed reach, the adjustments are more complicated owing to bed-material coarsening process. In order to quantify the adjustment characteristics of a total reach, a reach-averaged method was adopted to calculate the reach-scale bankfull channel dimensions firstly. Then the effects were investigated respectively of the altered flow-sediment regime and the bed-material coarsening degree on the variation in bankfull channel geometry. The results show that the effect of the altered flow-sediment regime on channel adjustments was lower in a coarsening bed reach than a less-coarsening one, because bed-material coarsening limited channel incision and led to a weaker response of channel adjustments to the variation in flow and sediment regime. Moreover, bed-material coarsening also had a significant influence on the adjustments in bankfull channel dimensions, with greater correlations being obtained in the reach suffering higher degree of bed-material coarsening. Therefore, a comprehensive hydraulic geometry relation was proposed to describe the channel adjustments in a gravel-sand bed reach, with these two influencing factors being considered. The obtained correlations were higher than those obtained from the simple relation that solely considered a single influencing factor.

Mechanochemical degradation (MCD) is a promising eco-friendly method to dispose persistent organic pollutants (POPs). Mechanically induced free-radical attack was thought to be one of the key elements in initiating and accelerating the dechlorination and degradation of POPs. In this study, mechanochemical formation of free-radicals and their roles in the remediation of hexachlorobenzene (HCB) contaminated soil were explored using both of experimental analysis and quantum chemical calculations. It was found that chlorinated phenoxy radicals(CB-O ) can be produced in the milling process and they played a vital role in the dechlorination of HCB, based on the results of electron spin-resonance (ESR) and X-ray photoelectron spectra (XPS). Two transition states of mechanochemical reaction along the formation of pentachlorinated phenoxy radical (PeCB-O ) were located, with the energy barriers of 39.4 and 3.4 kJ/mol. The localized orbital locator (LOL), Mayer bond order and topological analysis were also implemented to depict the process in detail. Free-radical attack dominated dechlorination pathway of HCB in the MCD process was also verified by the Fukui function analysis. The study on the mechanically-induced generation of free-radicals and their associated modes of action on the degradation of HCB will provide a deep insight into mechanochemical remediation mechanism of POPs contaminated soil.

Cation co-doping was proved an effective approach to reduce the metal-insulator transition (MIT) temperature (θc) of vanadium dioxide (VO2) for realizing excellent optical switching properties near room temperature, but its mechanism is remaining a great challenge. Herein, the Mg-W co-doped VO2 films are fabricated through hydrothermal growth. By changing the Mg content with maintaining 1 at% W doping level, it is observed that Mg dopants raise the θc of co-doped VO2 at a rate of ∼22 ℃ per at% Mg as the Mg content is less than ∼ 1 at%, but loses efficacy more than 1 at% Mg. The resistance of the co-doped VO2 films show the similar variation trend. The valence-band XPS spectra indicate that the Mg dopants counteract the VBE uplifting of VO2 caused by W dopants, consequently enlarging the optical band gap of W-doped VO2, which would partially explain the improvement of the visible light transmittance of W-doped VO2 induced by Mg dopants. The results clearly evidence that the charge compensation takes effect in the co-doped VO2, demonstrating the co-doping of high- and low-valent cations is unfavorable for effectively decreasing θc of VO2, and reveal the electron doping plays a key role in reducing θc.

The survivin (BIRC5) expression is very low in normal differentiated adult tissues, but it is one of the most widely upregulated genes in tumor cells. The overexpression of survivin in many cancer types has been positively correlated with resistance to chemotherapy, tumor metastasis, and poor patient survival. Survivin is considered to be a cancer specific biomarker and serves as a potential cancer drug target. In this report, we describe the design and syntheses of a series of novel selective survivin inhibitors based on the hydroxyquinoline scaffold from our previously reported lead compound MX-106. The best compound identified in this study is compound 12b. In vitro, 12b inhibited cancer cell proliferation with an average IC50 value of 1.4 μM, using a panel of melanoma, breast, and ovarian cancer cell lines. The metabolic stability of 12b improved over MX-106 by 1.7-fold (88 vs 51 min in human microsomes). Western blot analyses demonstrated that treatments with 12b selectively decreased survivin protein levels, but negligibly affected other closely related members in the IAP family proteins, and strongly induced cancer cell apoptosis. In vivo, compound 12b effectively inhibited melanoma tumor growth when tested using a human A375 melanoma xenograft model. Further evaluation using an aggressive, orthotopic ovarian cancer mouse model showed that 12b was highly efficacious in suppressing both primary tumor growth in ovaries and tumor metastasis to multiple peritoneal organs. Collectively, results in this study strongly suggest that the hydroxyquinoline scaffold, represented by 12b and our earlier lead compound MX-106, has abilities to selectively target survivin and is promising for further preclinical development.

Surface passivation and an increase in pH may restrain the efficiency and capacity of the zero-valent iron (ZVI) activated persulfate (PS) process. Mechanochemically sulfidated ZVI (S-ZVIbm) shows an extraordinary increase in the activation of PS. Ball-milling avoids the complex liquid reactions of traditional methods of activation and is easier to upscale. However, the effects of the sulfur dose and milling conditions have not been sufficiently investigated in the application of S-ZVIbm to the PS activation process. S-ZVIbm was pH-independent compared with similar catalysts. The best performance was obtained for S-ZVIbm with 25% sulfur synthesized at 300 rev min−1 for 5 h. Almost complete degradation of 50 μM ATZ was obtained after 40 min reaction with 6 mM PS and 0.3 g L-1 S-ZVIbm. Structural and species characterizations revealed the effects of the milling conditions and showed that sulfide (S2−) might be the predominant sulfur species. The primary facilitation mechanisms of S-ZVIbm were the mitigation of passivation, an increase in hydrophobicity, an increase in electron transfer and the accelerated regeneration of Fe2+. 57Fe Mossbauer spectrum confirmed that the Fe0 left in S-ZVIbm was about two times higher than that in reacted ZVIbm. Fe0 acted as the predominant PS activator, but FeS2, FeS and SO32− also contributed to PS activation. The degradation pathway of atrazine was clarified based on the detection of intermediates and density functional theory calculations. S-ZVIbm is a promising catalyst for the activation of PS used to remediate refractory contaminants and is amenable to upscaling from the laboratory scale.

In the past 50 years, the Shishou reach in the middle Yangtze River underwent significant channel evolution owing to the implementation of an artificial cutoff, the construction of bank revetment works and the operation of the Three Gorges Project (TGP). Based on the measured hydrological data and topographic data, the processes of channel evolution in this reach were investigated mainly from the adjustments in planform and cross-sectional geometries. The variation in planform geometry obtained in this study indicates that (i) the artificial cutoff at Zhongzhouzi caused the river regime to adjust drastically, with the mean rate of thalweg migration at reach scale of 42.0 m/a over the period 1966–1975; (ii) then the effect of this artificial cutoff reduced gradually, with the mean migration rate decreasing to 40 m/a owing to the occurrence of high water levels in 1993–1998; and (iii) the average annual rate of thalweg migration decreased to 29.3 m/a because of the impacts of various bank protection engineering and the TGP operation during the period 2002–2015. However, remarkable thalweg migration processes still occurred in local regions after the TGP operation, which resulted in significant bankline migration in local reaches of Beimenkou, Shijiatai, and Tiaoxiankou. In addition, the adjustments of bankfull channel geometry were investigated at section and reach scales after the TGP operation. Calculated results show that lateral channel migration in this reach was restricted by various river regulation works and that channel evolution was mainly characterized by an increase in bankfull depth and cross-sectional area. Empirical relationships were developed between the reach-scale bankfull dimensions (depth and area), the bankfull widths at specified sections, and the previous 5-year average fluvial erosion intensity during flood seasons, with high correlation degrees between them being obtained.

Remarkable channel degradation has occurred in the Jingjiang Reach of the Middle Yangtze River, since the operation of the Three Gorges Project, which has caused significant geomorphic adjustments, including the variation in bankfull discharge. Bankfull discharge is a key indicator of flood-discharge capacity in the Jingjiang Reach, which can adjust in response to the altered water and sediment conditions and local base-level changes. Therefore, it is important to investigate the variation in reach-scale bankfull discharge, because of longitudinal variability in channel geometry and bankfull discharge in the study reach. In this study, a general method to calculate the section-scale bankfull discharge using the simulated stage-discharge relation is outlined briefly, and an integrated method is then presented for estimating the reach-scale bankfull discharge. The post-flood reach-scale bankfull discharges in the study reach from 2002 to 2015 were calculated, using the proposed method, based on surveyed post-flood profiles at 171 sections and measured hydrological data at three hydrometric sections and eight water gauge sections. The calculated results indicate that: (i) the reach-scale bankfull discharge in the Jingjiang Reach ranged between 32,731 and 38,949 m 3 /s over this period, with the average bankfull discharge in the Upper Jingjiang Reach being generally greater than the value in the Lower Jingjiang Reach; (ii) the magnitude of the reach-scale bankfull discharge responded well to the cumulative effect of incoming flow and sediment conditions at the inlet boundary, as well as the change of local base level at the outlet boundary; and (iii) the flood-discharge capacity of the reach was controlled by both the upstream and downstream boundary conditions, and the reach-scale bankfull discharge was expressed by an empirical function of the previous five-year average fluvial erosion intensity during flood seasons at Zhicheng, and the difference between the flood-season average water stages at Zhicheng (upstream) and Lianhuatang (downstream), with a relatively high correlation degree between them being obtained. This relation for the prediction of reach-scale bankfull discharge was verified using the measurements in 2014–2015.

6:2 Fluorotelomer sulfonic acid (6:2 FTS) is used as alternative to perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) for different purposes such as chrome mist suppressant (CMS) and active ingredient in fire-fighting foams. In this study, degradability of 6:2 FTS under ultraviolet/persulfate (UV/PS) and ultraviolet/sulfite (UV/SF), which are typical technologies for advanced oxidation and reduction, were investigated respectively. Due to the hydrogenated moiety, 6:2 FTS was decomposed completely by UV/PS within 10 min, forming a mixture of short-chain perfluoroalkyl carboxylic acids with variable chain length (2-7 carbon atoms). Such oxidation products account for > 50% organofluorine of 6:2 FTS unmineralized portion. 6:2 FTS degradability under reductive UV/SF system was dramatically slowed down by the hydrogenated moiety, which lowered electron affinity and, consequently, reactivity with aqueous electron (eaq‾) produced by UV/SF. Fluorine mass balance showed that degradation intermediates were almost negligible: most of decomposed 6:2 FTS fluorine was converted to fluoride. A real 6:2 FTS-based CMS solution prepared from a commercial product was also tested. Both types of treatment were effective and in good agreement with the trends observed for tests with sole 6:2 FTS. Moreover, experimental results highlighted a remarkable amount of identifiable (like 4:2 FTS, 8:2 FTS and other per-/polyfluoroalkyl substances) and unidentifiable components in the CMS mixture. Indeed, fluoride concentration under UV/SF (73.8 mg/L) and UV/PS (44.9 mg/L) treatment were both higher than the estimated total concentration (

The ever growing importance of sustainable management of reservoir sedimentation has promoted the development and applications of turbidity current models. However, there are few effective and practical models in literature for turbidity currents in a reservoir where the impounded area involves both the main river and its many tributaries. An integrated numerical model coupling open-channel flow, turbidity current and flow exchanges between main river and tributaries is proposed, which can simulate the complex flow and sediment transport in a reservoir where these three physical processes coexist. The model consists of two sets of governing equations for the open-channel flow and turbidity current, which are based on the modified St. Venant equations by taking into account the effect of lateral flow exchanges. These two sets of equations are solved in the finite volume method framework and the solutions are executed in an alternating calculation mode. Different methods are respectively proposed to calculate the discharge of flow exchange caused by free surface gradient and turbidity current intrusion. For the surface-gradient driven flow exchange, a storage cell method, which re-defines the relationship between water level and representative cross-sectional area, is used to update the water level at confluence. For the turbidity current intrusion, a discharge formula is proposed based on the analysis of the energy and momentum transformation in the intruding turbid water body. This formula differs from previous ones in that the effect of tributary bed slope is considered. Two events of water-sediment regulation conducted in the Xiaolangdi Reservoir in 2004 and 2006 were simulated to test the ability of this model. The predicted reservoir drawdown process, the turbidity current evolution and the sediment venting efficiency were in close agreement with the measurements. The necessity to couple the flow exchanges was demonstrated by comparing the performance of the proposed model with different intrusion discharge formulas and the common one-dimensional model neglecting the main river and tributary interaction.

In the section of the Middle Yellow River from Longmen to the Sanmenxia Dam, the prediction to hyperconcentrated flood processes is difficult because of the abrupt change of channel geometry along the river and the high variability of the amount of flood water and sediment load from the main river and tributaries. A river network model based on a Godunov-type FVM scheme is proposed in order to investigate the flow dynamics, sediment transport and bed evolution during hyperconcentrated floods. A quasi 2D algorithm is adopted to calculate the velocity at the junction cell, which is then used for providing the interior boundary conditions. The computation for each reach can be executed simultaneously and the solution procedure is parallelized using OpenMP. The speedup factor compared with a serial program increases linearly in theory with the number of reaches in the river network. Two flood events, featuring significant erosion and deposition respectively, were simulated to validate the model. The calculated water levels, discharges and fractional concentrations of non-uniform suspended load were in agreement with the measurements. A comparison was made between the proposed model and an existing model neglecting the momentum conservation principle at the junction, with the former showing better prediction of the peak water levels near the confluence. Numerical experiments were conducted to analyze the influences of reservoir operation and discharge capacity of the dam on flood routing and bed evolution in the river network. It is demonstrated that decreasing pool level during flood season and increasing discharge capacity are both valid measures to alleviate sedimentation in the Sanmenxia Reservoir, and the former measure is a prerequisite. Therefore, the model presented here can help to enhance the understanding of river network system subject to high sediment input and inspire better strategies on sustainable reservoir management.

Fufang Banbianlian Injection (FBI), a well-known traditional Chinese medicine formula, has been recently approved and extensively used as a newly anti-inflammatory and anti-tumor drug. This prescription comprises an equal ratio of three traditional Chinese herbs, Lobelia chinensis Lour, Scutellaria barbata D. Don and Hedyotis diffusa Willd. The relationships between its chemical compositions and activities have not been understood well yet. To investigate the ingredients and their DNA-binding activities in FBI, an on-line high-performance liquid chromatography-diode-array detector-multi-stage mass spectrometry-deoxyribonucleic acid-4',6-diamidino-2-phenylindole-fluorescence detector (HPLC-DAD-MS(n)-DNA-DAPI-FLD) system was developed using a combination of chromatographic, mass spectrometric and fluorescent detection techniques. 4',6-Diamidino-2-phenylindole (DAPI) specifically binds to three ATT base pairs on the DNA minor groove, and thus can be used as a fluorescent probe for screening active compounds that compete ATT sequences with DAPI. Using this system, 21 of 58 identified or tentatively characterized compounds in FBI showed DNA-binding activities, with most of the active compounds being flavone glycosides. In addition, the structure-activity relationships of these active compounds suggested that conjugated planar structures are favorable for DNA-binding activities, and adjacent hydroxyl groups in flavonoids can significantly improve their activities. This is, to the best of our knowledge, the first application of DAPI as a fluorescent probe for the screening of DNA-binding active compounds in complex samples.

Summary Bank erosion is a key process in a fluvial system in the context of river dynamics and geomorphology. Since the operation of the Three Gorges Project (TGP), the Lower Jingjiang Reach (LJR) below the dam has experienced continuous channel degradation, with the phenomenon of bank erosion occurring frequently in local reaches. Therefore it is necessary to quantitatively investigate seasonal variations in the stability of composite riverbanks along the reach in order to better understand the fluvial processes in the reach. Laboratory tests were conducted for the sampled soils at six riverbanks during a field survey, with various bank soil properties being presented for the first time. These test results show that: the cohesive bank soils are relatively loose due to the high water contents of 28.5–40.0% and the low dry densities of 1.31–1.47 tonnes/m 3 ; and the cohesion or angle of internal friction generally decreases with an increase in water content of the cohesive soil. Based on the measured cross-sectional profiles and interpolated hydrological data, the near-bank hydrodynamic conditions and soil parameters of two typical composite riverbanks were then determined during the 2007 hydrological year. An improved method was proposed for calculating the stability at the mode of cantilever failure for the overhanging block of a composite riverbank, and the stability degrees of these two riverbanks were calculated at different stages. These results reveal that: (i) the incipient velocity of the non-cohesive lower bank had a magnitude of 0.4 m/s, less than the mean near-bank velocity of about 1.0 m/s, which led to intensive basal erosion especially during the flood season; (ii) the cohesive upper bank before failure had sufficient strength to resist direct fluvial erosion, but the failed soil mass deposited in the near-bank zone was disintegrated easily with the submerged immersion and was then transported downstream by fluvial entrainment; (iii) the degree of bank stability was relatively lower during the flood season, caused by the integrated effects of a process of severe basal erosion and a lower unit weight of 8.6 kN/m 3 for the submerged soil; and (iv) the degree of bank stability was lowest at the recession stage, which was caused by the vanishing of the hydrostatic confining pressure and the larger unit weight of 18.0 kN/m 3 for the saturated cohesive soil, because of a rapid drawdown in the in-channel water levels with the TGP operation.

The complete gene xyn // that encodes endo-1,4-β-xylanase secreted by Aspergillus usamii E001 was cloned and sequenced. The coding region of the gene is separated by only one intron. It encodes 184 amino acid residues of a protein with a calculated molecular weight of 19.8 kDa plus a signal peptide of 27 amino acids. The amino acid sequence of the xyn // gene has higher similarity with those of family 11 of glycosyl hydrolases reported from other microorganisms. The mature peptide encoding cDNA was subcloned into pET-28a(+) expression vector. The recombinant plasmid was expressed in Escherichia coli BL21-CodonPlus (DE3)-RIL, and xylanase activity was measured. The expressed fusion protein was analyzed by SDS-PAGE and a new specific band with molecular weight of about 20 kDa was found when induced by IPTG. Enzyme activity assay verified the recombinant protein as a xylanase. A maximum activity of 49.6 U mg −1 was obtained from cellular extract of E. coli BL21-CodonPlus (DE3)-RIL harboring pET-28a- xyn //. The xylanase had optimal activity at pH 4.6 and 50 °C. This is the first report on the cloning of a xylanase gene from A. usamii .