Accurate imaging of tumor hypoxia in vivo is critical for early cancer diagnosis and clinical outcomes, highlighting the great need for its detection specificity and sensitivity. In this report, we propose a probe (HTRNP) that simultaneously has hypoxia-targeting and hypoxia-responsive capabilities to enhance the tumor hypoxia imaging efficiency. HTRNP was successfully prepared through the encapsulation of Pt(II)-tetrakis(pentafluorophenyl)porphyrin (PtPFPP), which exhibits hypoxia-dependent phosphorescence, within the amphiphilic block copolymer OPDMA-PF, which has hypoxia-targeting tertiary amine N-oxide moieties and hydrophobic perfluorobenzene ring structures, which highly improved the loading content and water solubility of PtPFPP. By combining targeting and response abilities toward hypoxic conditions, the HTRNP micelles efficiently accumulate in the tumor tissues and emit intense phosphorescence, thus enabling ultrasensitive detection of various tumor models, even of hundreds of cancer cells, indicating its promising potential for early cancer detection and phenotypic characterization.

A portable platform for the visual determination of F- and Al3+ was developed by combining FeNPs@g-C3N4 nano-enzyme and a smartphone. The FeNPs@g-C3N4 nano-enzyme with excellent peroxidase activity was synthesized through the in situ growth of Fe nanoparticles (FeNPs) on graphite-phase carbon nitride nanosheets (g-C3N4), which could catalyze H2O2 to oxidize TMB to blue oxide (oxTMB). The peroxidase activity of the FeNPs@g-C3N4 nano-enzyme could be inhibited by F-, and then restored by Al3+ because of the coordination reaction between Fe3+/Al3+ and F-. Furthermore, the solution color could be dynamically manipulated by changing the concentrations of F- and Al3+. Under optimal conditions, the developed method gave low detection limits of 2.43 nM for F- and 7.66 mu M for Al3+. The cooperation of nano-enzyme and smartphone has greatly shortened the detection time and reduced the cost of detection, providing a new strategy for the on-site and convenient detection of F- and Al3+ in tea, and showed significant application potential in food safety evaluation.

A suspension bridge that uses suspension cables as the major bearing structure has the most robust spanning capacities. There are two types of anchorage: gravity-type anchorage and tunnel-type anchorage (TTAs). The TTAs structure exhibits complex mechanical and deformation characteristics under tens of thousands of tons of load transferred from bridge cables. A large-scale field model test method is proposed to reveal the mechanical rock mass properties of the TTAs under different loading conditions, and its theoretical and related technologies are studied based on more than twenty years of applications. Four parts are included in the study. Firstly, the technical development of the TTAs model test is summarized with practical engineering applications. On this basis, the theoretical basis of the field model test of the TTAs is studied from two aspects: the scale representativeness and the similarity theory of the model test. The technical points of the recommended TTAs field test are proposed in the third section. Finally, to evaluate the potential bearing properties of the TTAs in a planned super-large railway suspension bridge, a case study with a large-scale TTAs model test in the field is introduced. The test results show that TTA technology can supply sufficient bearing capacity to the high-tonnage railway suspension bridge with a total cable load of 860MN under complex and fractured rock mass condition. The composite TTAs structure bearing a load of tens of thousands of tons transferred from main cables in the design of highway or railway suspension bridges represents significant technical progress in rock mechanics.

The water-level fluctuation zone of the lower Jinsha River Basin is a fragile ecosystem with limited water resources in the southwest of China. Soil water is critical for maintaining ecological balance and promoting the healthy development of animals and plants in this region. In this study, eight typical soil profiles were monitored for hydrochemistry in soil-soluble salt from upstream to downstream of the lower Jinsha River Basin. The results show that the soil water content was low and had a negative correlation coefficient with major ions in the soil-soluble phase. The soil-soluble salt is slightly alkaline, and Ca2+, Na+, SO42−, and HCO3− are important components for ions in a soluble phase. Major ions in soluble salt originate from various sources, including precipitation, anthropogenic input, silicate weathering, and carbonate weathering, and the contribution rates from each end member were 0.7%, 45.1%, 25.2%, and 29%, respectively. The ion composition in surface soil soluble salt is mainly influenced by precipitation and human activities, while the ions in the 0–50 cm soil layer originate from the precipitation input and water-rock interaction. In addition, rock weathering is a vital process for releasing ions into soil-soluble salt from 50 to 100 cm soil layer. Our findings provide important references for ion sources and the eco-hydrological process in limited water resources in the water-level fluctuation zone of the lower Jinsha River Basin.

适宜植物遴选是干热河谷库区消落带修复的关键.为筛选干热河谷库区消落带修复适宜耐淹抗旱植物,检验消落带修复有效性,本文以乌东德水电站库区己衣镇新民村消落带修复区为研究对象,结合定量与定性分析方法,观察并分析了不同物种、大小规格、种植海拔的植物在长期水淹后的生长和恢复情况.结果表明:(1)少量乡土植物可在消落带上段生长存活,乡土植物桑树、狗牙根、苍耳、苘麻可在整个消落带区域生长;(2)引进植物池杉、中山杉、乌桕、枫杨、小梾木、秋华柳可在干热河谷库区消落带区域生长;(3)大规格苗木在消落带生长更好,种子播种修复效果不佳;(4)修复区植物生长受干热气候、病虫害和种间竞争等因素影响.研究结果可为后续干热河谷库区消落带修复研究积累基础数据与实践经验.

干热河谷库区消落带生态修复关键技术难点在于当消落带植被受到长时间淹水与干旱交替双重胁迫时,如何遴选生态修复两栖植物.通过对乌东德库区消落带生态修复试验段淹没前植被调查、溪洛渡库区和三峡库区典型库岸消落带现存植物种群调查以及查阅三峡库区消落带植被自然演替和植被修复相关文献,结合乌东德水电站水位调度节律和库区干热河谷气候条件,对乌东德库区消落带植被自然演替趋势进行了分析.按照自然修复与人工修复相结合、乡土植物与外来植物相结合的消落带生态修复理念,遴选出乌东德库区消落带生态修复试验植物,提出了在试验段沿海拔高程的植物梯度配置模式:消落带中下部配置以狗牙根、香附子、扁穗牛鞭草等为主的多年生草本植物和以苘麻、狗尾草、马唐等为主的一年生草本植物;消落带上部配置以中山杉、水桦、桑树、秋华柳、银合欢等为主的乔、灌木以及草本植物.

干旱沙漠区水资源是改善生态环境和促进动植物生存的关键.综合古尔班通古特沙漠研究成果,分别对该沙漠气候特征、水分分布和水分来源、水分循环和生态水文过程等方面进行归纳,指出现有研究存在的不足.在此基础上对古尔班通古特沙漠今后研究的方向和内容进行展望,指出将该沙漠不同水体纳入整体研究,以期丰富该沙漠生态水文机制和进一步探讨干旱区水文循环过程.

Immune checkpoint blockade (ICB) therapies that target programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway are currently used for the treatment of various cancer types. However, low response rates of ICB remain the major issue and limit their applications in clinic. Here, we developed a ROS-responsive synergistic delivery system (pep-PAPM@PTX) by integrating physically-encapsulated paclitaxel (PTX) and surface-modified anti-PD-L1 peptide (pep) for combined chemotherapy and ICB therapy. Pep-PAPM@PTX could bind the cell surface PD-L1 and drive its recycling to lysosomal degradation, thus reverting PTX-induced PD-L1 upregulation and downregulating PD-L1 expression. As a result, pep-PAPM@PTX significantly promoted T cell infiltration and increased tumor immunoactivating factors, synergizing PTX chemotherapy to achieve enhanced anticancer potency in a triple-negative breast cancer (TNBC) model.

洪涝灾害是制约我国社会经济可持续发展的重要灾害.洪涝灾害评估研究是实现其有效防治的重要依据.本文根据《洪涝灾情评估标准》(SL 579—2012),选择死亡人口、受灾人口、农作物受灾面积、直接经济损失、水利设施经济损失、倒塌房屋、骨干交通中断历时、城市受淹历时、生命线工程中断历时等内容作为评估指标,以2017年度重庆市洪涝灾害作为研究对象,探讨境内暴雨洪灾分布规律.研究结果显示,2017年重庆市境内发生的13次区域性暴雨和1次局部暴雨,共计造成1.41×106人受灾,直接经济损失1.594×109元,其中,9月洪涝灾害损失最为严重.从受灾区域分布来看,渝东北开州、万州、巫溪等区(县)损失严重,渝西部地区灾害损失相对较轻.从场次洪涝灾害和年度洪涝评估结果来看,2017年属一般洪涝灾害年.本研究可为洪涝灾害评估提供方法借鉴,为暴雨洪灾防御工作提供数据与理论支撑.

Hubei Yanji Yangtze River Bridge integrates the functions of expressway and urban road. It adopts the scheme of 1860 m double deck steel truss girder suspension bridge with a single span across navigable waters and fault zones. The bridge is close to the airport, and the height of the tower is limited due to the aviation height limit, so that the sag of the main cable is too small and the scale of the main cable is too large. To solve the above problems, a new suspension bridge structure system with four main cables with different sags is proposed. The main features of this system are: four main cables are symmetrically arranged on two sides, and two main cables on the same side adopt different sags. The truss girders are alternately suspended on two groups of main cables with different sags at intervals, and the main cables with different sags are staggered and anchored to ground anchors in front and back of the longitudinal direction. The new system reduces the scale of a single main cable, and has better wind stability. The midspan of lower main cable on the outside can be lowered below the bridge deck to increase the sag, which better solves the construction problem of the tower height limitation. Based on this system, the upper main cable span of the bridge is (550+1860+450) m, the midspan sag is 142.445 m, the lower main cable span is (510+1860+410) m, and the midspan sag is 153.345 m. The cable of the bridge adopts galvanized-aluminium alloy coated high-strength steel wire, the girder adopts Warren truss, the anchorage adopts replaceable prestressed anchorage system, the tower adopts gatehouse shape, and the foundation adopts bored piles.

作为三峡库区生态调节前置库,汉丰湖水质受流域内农业面源污染和城市生活污染的影响.开展汉丰湖正式运行前后流域水环境演变特征分析研究,明确影响水体营养状态的关键因素,对汉丰湖水环境保护乃至改善三峡库区水环境具有重要的参考意义.本研究综述了2012—2019年汉丰湖水质监测数据相关文献,各指标的质量浓度监测结果表明:溶解氧(DO)、总磷(TP)和高锰酸钾指数(CODMn)年变化较大,总磷(TN)、氨氮(NH+4-N)年浓度差异不显著;TN和NH+4-N随着月份增加整体呈下降趋势,DO、CODMn和叶绿素a(Chla)随着月份增加整体呈先增加后降低趋势,TP随月份增加整体呈先降低后增加的趋势;各监测点位的水体DO、TN、NH+4-N、TP和CODMn质量浓度差异均不显著.汉丰湖水体质量等级为Ⅲ至劣Ⅴ类,呈中营养至轻度富营养状态,TN是主要污染指标.Chla与DO、TN呈显著正相关,与NH+4-N呈正相关,与CODMn和TP呈负相关关系,藻类的生长与溶解氧、氮素含量增加有关.为改善汉丰湖的水体富营养化问题,本文提出了污染源控制、水文调度和生态补偿措施.

The shear (tau(p)), creep (tau(c)), and long-term shear (tau(infinity)) strengths of moraine soil are mechanical properties of high concern during the engineering construction and management process and were obtained by conducting large-scale direct shear and shear creep tests on the soil layer at the Dadu river bridge in Luding, China. The size of the test samples was about 1.0 x 1.0 x 0.50 m (length x width x height). The shear strength and creep behavior under different normal (sigma) and shear (tau) stresses were analyzed, and the long-term shear strength was obtained from stress-displacement isochronal curves during the creep process. The results indicate that the shear strength of moraine soil relates to the content and distribution of large particles. The shear strength parameter of moraine soil is 0.765 (phi = 37 degrees) and the cohesion parameter (c) is 64.2 kPa. The moment of the maximum creep displacement rate at the primary creep stage depends on the shear stress. The step-like increasing and jumping of shear creep displacement are evident during the middle-process of the secondary creep stage (e.g., 20-60 h when tau is 411 kPa under sigma of 300 kPa), due to large particles rotating or overturning under high shear stresses. The empirical Burgers model predicts the creep displacement well. The ratio (tau(infinity)/tau(p)) of long-term to shear strength ranges from 0.53 to 0.92, indicating that the creep effect has decays in the shear strength of moraine soil. The ratio (tau(infinity)/tau(c)) of long-term to creep strength ranges from 0.65 to 0.85, indicating that moraine soil could easily transfer from viscous creep deformation to shear failure when the loading stress is higher than long-term strength. The results provide a valuable reference for shear strength analysis and long-term strength assessment of moraine soil regions.

Illustration of the fluorescent ratio probe (OPDEA/BOD-NO2) with hypoxia targeting and hypoxia activation capacity for in vivo tumour imaging.

采用混凝土喷护坡面苔藓调查以及苔藓植生技术室内与现场实验等手段,开展了生态基层水泥含量对苔藓生长影响研究,研制了抗雨水冲刷苔藓植生基层,提出了基于苔藓植生技术的混凝土喷护坡面生态重建新技术.研究结果表明:(1)黄砂藓和细叶真藓可以作为重庆地区混凝土喷护坡面生态重建耐旱苔藓藓种.苔藓作为混凝土喷护坡面生态重建的先锋植物,可为后期伴生草本植物的生长创造生境.(2)采用河沙和菜园土作为苔藓植生基层主要基质、水泥质量占比为10％～20％时,既能满足苔藓植生基层抵抗雨水冲刷的要求又能满足苔藓生长的需要.(3)苔藓作为混凝土喷护面生态重建的先锋植物,可为后期伴生草木植物的生长创造微生境,从而达到提高生物多样性目的.研究结果可为混凝土边坡的生态修复提供技术参考和实践经验.

植物是水库消落带重要组成部分,具有水土保持、污染过滤、物种多样性维持、景观美化等多种生态功能.为系统揭示干热河谷库区消落带植被演替趋势与规律,2019年7月至2020年7月对金沙江干热河谷乌东德库区消落带生态修复试验区水位上涨前的植被现状进行踏查与样方调查,分析了水淹前植物生长现状、特有的植物区系成分和植物种类.研究结果表明:(1)试验地共有维管束植物46科102属112种,其中禾本科、菊科和豆科植物种类最丰富,单科单属现象明显,一年生植物优势明显,具有典型的萨王纳植被特征;(2)群落类型包括车桑子+扭黄茅群落、银合欢+滇刺枣+扭黄茅群落和银合欢纯林群落,结构单一脆弱,人为干扰严重;(3)植物区系成分以热带为主,多为耐旱物种;(4)试验区经历水淹后,原有适应陆生环境的耐旱木本植物物种可能逐步减少,草本植物优势进一步增强,不同生活型植物占比发生改变,具体变化有待后续长期生态监测.研究结果可为后续干热河谷库区消落带生态修复研究与实践提供基础数据与参考依据.

Pyroptosis has been reported to improve the immunosuppressive tumor microenvironment and may be a strategy to enhance osteosarcoma treatment. The extent to which modulation of mitochondria could induce tumor pyroptosis to enhance immunotherapy has not been characterized. We synthesized a mitochondria-targeting polymer micelle (OPDEA-PDCA), in which poly[2-(N-oxide-N,N-diethylamino)ethyl methacrylate] (OPDEA) was used to target mitochondria and the conjugated dichloroacetate (DCA) was used to inhibit pyruvate dehydrogenase kinase 1 (PDHK1). This conjugate induced pyroptosis through initiation of mitochondrial oxidative stress. We found that OPDEA-PDCA targeted mitochondria and induced mitochondrial oxidative stress through the inhibition of PDHK1, resulting in immunogenic pyroptosis in osteosarcoma cell lines. Moreover, we showed that OPDEA-PDCA could induce secretion of soluble programmed cell death-ligand 1 (PD-L1) molecule. Therefore, combined therapy with OPDEA-PDCA and an anti-PD-L1 monoclonal antibody significantly suppressed proliferation of osteosarcoma with prolonged T cell activation. This study provided a strategy to initiate pyroptosis through targeted modulation of mitochondria, which may promote enhanced antitumor efficacy in combination with immunotherapy.

干热河谷是我国西南地区一种特殊的自然景观,生态环境极端脆弱,加之消落带涉及面广,类型复杂,自我修复缓慢,增加了干热河谷生态治理的难度.为明确干热河谷生态治理的发展方向,介绍了干热河谷的基本情况,系统回顾了土壤类型、理化性质、水分分布和植被恢复技术、种类选择以及消落带治理方面的研究进展.目前干热河谷生态治理存在微观研究不够深入、缺乏长期动态监测、生态恢复效益评估指标单一化等不足,亟需应用先进技术手段,合理筛选优良的当地植物种类,建立生态环境长期动态监测与评估体系,加强生态系统自我修复功能,更科学有效地开展干热河谷生态治理.

金沙江干热河谷是我国重要的水利水电开发区.该区域水电站水库建成运行后将产生大面积库区消落带,严重威胁当地生态环境.本文从金沙江干热河谷水电站库区消落带植被现状、物种筛选、植物生理生态响应、植被恢复模式与技术、恢复生态效益评价等方面概括总结了该区域植被恢复研究进展与现状.针对金沙江干热河谷水电站库区消落带现有植被恢复研究实践不足的现状,提出该区域植被恢复宜根据地形地貌,结合生物技术和工程技术,综合利用多种生活型植物的植被恢复思路,指出金沙江干热河谷水电站库区消落带植被恢复未来研究重点,包括实践与示范、生态系统长期动态监测和管理政策研究等方向.

Finite element model updating is significant in damage detection, parameter identification and structural control, yet practical applications to large-scale structure reveal a major defect in computational efficiency. In this paper, an improved substructure-based response sensitivity method is presented to accelerate the convergence of model updating. The equivalent mode is derived to relate higher modes to lower modes. The motion equation is reduced and simplified using the equivalent mode and a small number of lower modes in each substructure. The structural response and response sensitivity are then computed efficiently from the small-sized motion equation. The inertial effect of the discarded higher modes is compensated by deriving an equivalent modal mass matrix related to mass matrix and equivalent mode in the reduced mass matrix. This compensation helps ensure the accuracy of structural response and response sensitivity, avoiding retaining numerous lower modes. The substructure-based response sensitivity method is later developed to conduct the finite element model updating of large-scale structures. The accuracy and efficiency of the proposed method are finally tested by two numerical simulations and one experimental case. (C) 2020 Elsevier Ltd. All rights reserved.

The inhomogeneity of layered rock mass is mainly contributed by the inhomogeneity of bedrock and the inhomogeneity of bedding plane joints. It is important to consider the different homogeneity of bedrock and bedding plane joints. Therefore, this paper combines the WLPB model and the WSJ model to characterize the inhomogeneity of bedrock and bedding plane joints, respectively. We put forward a new theory and calculation method of micro-inhomogeneous contact mechanics model of bedded rock mass, and analyze the deformation characteristics, failure modes and micro-evolution laws of bedded rock samples under uniaxial compression. The results show that the elastic modulus, peak strength and failure mode of layered rock samples present obvious anisotropic characteristics, which are in general consistent with the laws of laboratory tests. It demonstrates the rationality and adaptability of the developed inhomogeneous microcosmic contact model of layered rock mass. When the mechanical behavior of layered rock mass is controlled by the bedding plane, the inhomogeneity of bedding plane becomes an important factor affecting the macromechanical characteristics of layered rock mass. When the bedding plane plays a controlling role, the influence of bedding plane spacing is not obvious on the peak strength of layered rock samples, but it is obvious on the deformation characteristics of rock samples. The paper reveals the micro fracture mechanism and transformation law controlled by the inhomogeneity of bedding plane of layered rock mass with different inclination angles under uniaxial compression.