Different from other 3D printing techniques such as selective laser sintering (SLS), stereolithography (SLA), three-dimensional printing (3DP), and laminated object manufacturing (LOM), the fused ...deposition modeling (FDM) technology is widely used in aerospace, automobile making, bio-medicals, smart home, stationery and training aids, and creative gifts for its easy use, simple operation, and low cost. The polylactic acid (PLA) is a material most extensively applied in FDM technology for its low melting point, non-poison, non-irritation, and sound biocompatibility. The FDM 3D-printed PLA parts are a research hotspot in the 3D printing field. This paper is intended to sum up the latest research results and achievements made in recent years in the interface bonding property, mechanical properties, and shape precision promotion of FDM 3D-printed PLA parts as well as the functional expansion of the PLA parts based on vast domestic and overseas literature. The literature research collection focuses on the following two aspects: one is the macroscopic technical research on the optimal settings of key technological parameters; the other one is the PLA modification research on improvement of cross-linking state and crystallinity of PLA molecular chains, carbon reinforced phase modification of PLA, and PLA functional compound modification. The researches in the two aspects are of importance in improving whole properties, enhancing functional applications, and expanding and enriching the applications of FDM 3D-printed PLA parts. This paper is expected to give some helps and references to the researchers who are specializing in the 3D printing field.
Leaching is one of the main causes of water damage to the highway base, which can aggravate under the vibrations of the highway load and substantially deteriorate the durability of highway. To ...investigate the effect of the leaching of cement stabilized macadam (CSM) under vibration condition, a new method was reported in this study accelerate the leaching of CSM in a laboratory by changing the parameters such as vibration frequency, vibration time, leaching medium, etc. The vibration leaching behavior and damage evolution of CSM were studied by comparing the results of the vibration non-leaching test and the vibration leaching test. The main test indexes were calcium ion concentration, pH, leaching depth, ultrasonic wave velocity, unconfined compressive strength, splitting strength and acoustic emission amplitude. The results indicated that vibration could accelerate the leaching efficiency, and the acceleration effect can be changed by changing the vibration frequency. The performance of CSM considerably deteriorated due to leaching. With the increase in the leaching time, the leaching depth increased continuously, and the unconfined compressive strength and splitting strength decreased considerably; moreover, the damage accumulation increased. The durability of CSM was substantially reduced. The effect of the leaching of low-dose CSM is more obvious than that of high-dose CSM.
The fiber pullout is a main failure after the fiber is broken in the tension of glass fiber reinforced polymer (GFRP) bolt. In this paper, the numerical analysis is done on the distribution of both ...fiber normal force and interface shear stress. The results show that, on the ideal interface, the fiber pullout occurs from the lower end to the upper end of the matrix gradually, and both the normal stress of the fiber and the shear stress of the ideal interface gradually increase from the lower end to the upper end. With the increase of the interface layer thickness, the shear stress concentration area on the interface is enlarged while the stress applied is reduced, and the displacement of GFRP deformation is increasing sharply. This means that the capacity of GFRP deformation is enhanced. As a soft elastic body, the interface layer with a smaller elastic modulus can make the fiber stress and the interface shear stress sharply small and well dispersed. In addition, the load can be effectively transferred to the reinforced phase fibers in a bigger interfacial layer elastic modulus with a certain strength.
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•Ecological sources were identified using morphological spatial pattern analysis.•Resistance surface was developed from ecosystem service value.•Ecological corridors were identified ...using minimum cumulative resistance model.•The ecological network was optimized by similarity search.
Ecological infrastructure is a popular framework for conservation planning. In this paper, one of the most urbanized regions of China-Shenzhen was chosen as the study area. Ecological infrastructure with different configurations and functions were identified and combined to form the urban ecological network. The ecological sources were identified using morphological spatial pattern analysis (MSPA) and landscape connectivity analysis. The ecological resistance surface developed from ecosystem service value was modified basing on ecological sensitivity and landscape connectivity. The ecological network was constructed by minimum cumulative resistance (MCR) model and then optimized and accessed. The results show that: (1) the ecological network consists of 25 ecological sources distributed mainly in the southeast and west. Twenty-nine ecological corridors were extracted and 36 ecological nodes identified. (2) In the optimized ecological network, 10 new ecological sources were added, and 46 ecological corridors and 59 ecological nodes were identified. It would promote the connectivity of the ecological sources and the stability of ecological functioning process. (3) The ecological network took ecosystem service value and ecological sensitivity into consideration and lays emphasis on improving landscape connectivity, providing an approach to optimizing urban ecological network and contributing to urban planning.
Excessive activation of hepatic stellate cells (HSCs) is a key step in liver fibrogenesis. Here we report that CUG-binding protein 1 (CUGBP1) expression is elevated in HSCs and positively correlates ...with liver fibrosis severity in human liver biopsies. Transforming growth factor-beta (TGF-β) selectively increases CUGBP1 expression in cultured HSCs in a p38 mitogen-activated protein kinase (MAPK)-dependent manner. Knockdown of CUGBP1 inhibits alpha smooth muscle actin (α-SMA) expression and promotes interferon gamma (IFN-γ) production in HSCs in vitro. We further show that CUGBP1 specifically binds to the 3' untranslated region (UTR) of human IFN-γ mRNA and promotes its decay. In mice, knockdown of CUGBP1 alleviates, whereas its overexpression exacerbates, bile duct ligation (BDL)-induced hepatic fibrosis. Therefore, CUGBP1-mediated IFN-γ mRNA decay is a key event for profibrotic TGF-β-dependent activation of HSCs, and inhibiting CUGBP1 to promote IFN-γ signalling in activated HSCs could be a novel strategy to treat liver fibrosis.
Hepatic stellate cell (HSC)-targeted delivery is an attractive strategy for liver fibrosis therapy, but the efficacy is hampered by poor delivery of nanomaterials and complicated microenvironments of ...the fibrotic liver. Here, we report a versatile CXCR4-inhibiting nanocomplex composed of polymeric CXCR4 antagonism (PAMD, PA), CLD (clodronate) and siPAI-1 (siRNA of plasminogen activator inhibitor-1) that surmounts multiple barriers to improve the outcome by co-regulating Kupffer cells (KCs), extracellular matrix (ECM) and HSCs. Upon encountering biological barriers, the nanocomplex exerted penetrating and targeting functions, efficiently overcoming KCs capture, ECM trapping and nonspecific recognition of HSCs, finally contributing to the enhanced HSCs uptake. Moreover, an enlarged antifibrotic activity is realized through synergetic regulation of KCs apoptosis, ECM degradation and HSCs inactivation. Overall, such a versatile nanocomplex provides a framework for designing HSC-targeted delivery system and has valuable potential as a novel antifibrotic strategy.
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The ecological security pattern (ESP) focuses on key ecological elements in ecosystems by identifying, combining, and evaluating these elements. This study attempts to identify the ESP of the Pearl ...River Delta (PRD) and provide suggestions for optimization. Ecosystem services were calculated and applied to construct the ecological resistance surface; morphological spatial pattern analysis (MSPA) and landscape connectivity analysis were used to identify ecological sources; and minimum cumulative resistance (MCR) model was applied to extract ecological corridors and ecological nodes. The results show that during 1995 to 2015, the main landscape transformation occurred between forest, cropland, and urban land, and the location of the transformation was mainly in the central part of the study area. Regarding the ESP, the average resistance value increased from 0.30 to 0.33; the area of ecological sources decreased by 5.12%; the ratio of total cumulative resistance to the length of the corridors increased by 14.82%; and the number of ecological nodes increased from 71 to 99. For the ESP optimization, based on the correction of the resistance surface, 1348 km blue corridors and 61 blue nodes were extracted. Based on hot spot analysis, nine stepping stones were identified. This optimization compensates for the lack of ecological elements in the center of the study area, enhances weaker corridors, and improves the connectivity of the ESP, thus making the ESP more stable and complete. The ESP constructed and optimized in this paper holds great significance and serves as a valuable reference for ecological protection and environmental management.
•Effects of water matrices on 36 micropollutants degradation by UV/NH2Cl were investigated.•Linear function was found between RCS and RNS activity and Hammett Σσ+ constant.•Cl− enhanced Cl2•– ...formation, leading to increased removal of some micropollutants.•Br− inhibited micropollutant degradation due to lower reactivity of RBS than RCS.•I− produced HOI and RIS, facilitating the degradation of phenols and sulfonamides.
The UV/monochloramine (UV/NH2Cl) process has attracted increasing attention in water treatment, in which hydroxyl radicals (HO•), reactive chlorine species (RCS) and reactive nitrogen species (RNS) are produced. This study investigated the effects of water matrices including halides, natural organic matter (NOM), alkalinity and pH, on the degradation kinetic of a variety of micropollutants and radical chemistry in the UV/NH2Cl process. The presence of chloride blunted HO• and Cl• impacts, but enhanced Cl2•– effect on micropollutants reactive toward Cl2•–. The presence of 30 μM bromide led to an 82% decrease in the specific pseudo-first-order rate constants (k′) by HO• (kHO•′), and significantly diminished RCS efficacy. Reactive bromine species (RBS) were formed in the presence of bromide, while the contribution could not compensate for the decrease of HO• and RCS due to their lower reactivity toward micropollutants. Iodide rapidly transformed to HOI via reacting with NH2Cl, which resulted in a 59% decrease of kHO•′ and 12% ∼ 100% decreases of k′ by reactive halogen species (RHS) and RNS (kRHS + RNS′) for most micropollutants. Nevertheless, k′ of phenolic compounds, such as paracetamol, bisphenol A and salbutamol, increased in the presence of iodide by 78%, 360% and 130%, respectively, due to the roles of HOI and reactive iodine species (RIS). Bicarbonate decreased the contributions of HO• and RCS, but enhanced that of CO3•− for micropollutants reactive toward CO3•−. The presence of 1 mg/L NOM scavenged over half the amount of HO•, and also consumed RCS and RNS, resulting in significantly decreased removal of micropollutants. High pH value witnessed enhanced degradation for those micropollutants reactive toward RCS and RNS through deprotonation. The degradation of most micropollutants was inhibited in real drinking water and in the coexistence of halides. This study provides a better understanding of radical chemistry in the UV/NH2Cl process under a practical water treatment condition.
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•The microclimate regulation effects of urban blue-green infrastructures were studied.•Distance, surface type and reservoir capacity significantly affect temperature field.•The cooling effect of ...reservoir remarkably decreased beyond a certain range.•The effects of reservoir and vegetation on peripheral temperature had interactions.•The contribution ratio of reservoirs’ cooling effect declined as distance increased.
Blue-green infrastructures, including reservoirs, lakes, forests and green spaces, play important roles in the microclimate environment. This study investigated the effects of blue-green infrastructures on the surface temperature adjacent to 12 reservoirs in the Pearl River Delta area, China. The temperature of each reservoir and its surrounding environment was retrieved by Landsat Thematic Mapper (TM) remote sensing imagery. The relationship between the temperature fields around the reservoir and the influencing factors was analyzed with statistical analysis. The results showed that distance (D), underlying surface type, and reservoir capacity (V) had significant effects on the temperature fields around the reservoirs. The temperatures across distances of 0–100 m and 0–200 m away from the reservoir boundary had a linear relationship with distance. The effect of the reservoir on temperature gradually declined when the distance exceeded 200 m. In the 0–300 m range, a quadratic equation with an intercept best fitted the relationship between temperature and distance. Four types of underlying surfaces, including built-up land, bare land, sparse forest land and forest land, were quantified by the normalized difference vegetation index (NDVI). Subsequently, a quadratic model expressing the correlation between temperature and the NDVI was obtained. Moreover, the surface temperature at the reservoir edge was negatively correlated to V. Finally, a multiple nonlinear regression equation was found to effectively describe the influence of D, NDVI and V on temperature fields around reservoirs. The influence of reservoir and vegetation (i.e., NDVI) on the field and their contributions were calculated by mathematical methods. The effects of the reservoir and vegetation on the peripheral temperature interacted with each other; the influence of the reservoir and the vegetation on temperature declined and increased, respectively, as distance increased. By addressing the influence of reservoirs and forests on temperature fields and cooling contribution rates, this study provides more insight into the role of blue-green infrastructure in the urban thermal environment.
Blocking PD-1/PD-L1 signaling transforms cancer therapy and is assumed to unleash exhausted tumor-reactive CD8+ T cells in the tumor microenvironment (TME). However, recent studies have also ...indicated that the systemic tumor-reactive CD8+ T cells may respond to PD-1/PD-L1 immunotherapy. These discrepancies highlight the importance of further defining tumor-specific CD8+ T cell responders to PD-1/PD-L1 blockade. Here, using multiple preclinical tumor models, we revealed that a subset of tumor-specific CD8+ cells in the tumor draining lymph nodes (TdLNs) was not functionally exhausted but exhibited canonical memory characteristics. TdLN-derived tumor-specific memory (TTSM) cells established memory-associated epigenetic program early during tumorigenesis. More importantly, TdLN-TTSM cells exhibited superior anti-tumor therapeutic efficacy after adoptive transfer and were characterized as bona fide responders to PD-1/PD-L1 blockade. These findings highlight that TdLN-TTSM cells could be harnessed to potentiate anti-tumor immunotherapy.
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•TdLN-TTSM cells are bona fide memory T cells•Exhaustion-associated epigenetic scaring marks TPEX but not TdLN-TTSM cells•Adoptive transfer of TdLN-TTSM represents a promising immunotherapy strategy•TdLN-TTSM cells are primary responders to PD-1/PD-L1 ICB
Huang et al. demonstrate different functional states of tumor-reactive CD8+ T cells in the TdLNs where TCF-1+TOX− CD8+ T cells are bona fide memory T cells and function as the genuine responders to PD-1/PD-L1 ICB.
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