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The cardiovascular diseases (CVD) continue to be the major threat to global public health over the years, while one of the effective methods to treat CVD is stent intervention. Biomedical magnesium (Mg) alloys have great potential applications in cardiovascular stents benefit from their excellent biodegradability and absorbability. However, excessive degradation rate and the delayed surface endothelialization still limit their further application. In this study, we modified a Mg-Zn-Y-Nd alloy (ZE21B) by preparing MgF 2 as the corrosion resistance layer, the dopamine polymer film (PDA) as the bonding layer, and hyaluronic acid (HA) loaded astaxanthin (ASTA) as an important layer to directing the cardiovascular cells fate. The electrochemical test results showed that the MgF 2 /PDA/HA-ASTA coating improved the corrosion resistance of ZE21B. The cytocompatibility experiments also demonstrated that this novel composite coating also selectively promoted endothelial cells proliferation, inhibited hyperproliferation of smooth muscle cells and adhesion of macrophages. Compared with the HA-loaded rapamycin (RAPA) coating, our MgF 2 /PDA/HA-ASTA coating showed better blood compatibility and cytocompatibility, indicating stronger multi-functions for the ZE21B alloy on cardiovascular application. [ABSTRACT FROM AUTHOR]

• Radial compressive stress was introduced in the degradation test of mg microtubes. • Dynamic medium and radial compressive stress accelerate mg microtubes degradation. • The degradation mechanism of mg microtube under different environments was proposed. The degradation of Mg alloys relates to the service performance of Mg alloy biodegradable implants. In order to investigate the degradation behavior of Mg alloys as vascular stent materials in the near service environment, the hot-extruded fine-grained Mg-Zn-Y-Nd alloy microtubes, which are employed to manufacture vascular stents, were tested under radial compressive stress in the dynamic Hanks' Balanced Salt Solution (HBSS). The results revealed that the high flow rate accelerates the degradation of Mg alloy microtubes and its degradation is sensitive to radial compressive stress. These results contribute to understanding the service performance of Mg alloys as vascular stent materials. [ABSTRACT FROM AUTHOR]

• A multifunctional coating was constructed on ZE21B alloy for biodegradable vascular stents. • MgF 2 layer and hydrophilic polymers in the functional coating could effectively protect ZE21B alloy from overfast degradation. • Anticoagulant ACH 11 peptides and ECs-selective REDV peptides in the functional coating could dramatically enhance the hemocompatibility and pro-endothelialization capacity of ZE21B alloy. • The functional coating systematically improved the corrosion resistance and biocompatibility of ZE21B alloy in vitro and in vivo. Biodegradable magnesium alloy stents (MAS) have great potential in the treatment of cardiovascular diseases. However, too fast degradation and the poor biocompatibility are still two key problems for the clinical utility of MAS. In the present work, a functional coating composed of hydrophilic polymers and bioactive peptides was constructed on magnesium alloy to improve its corrosion resistance and biocompatibility in vitro and in vivo. Mg-Zn-Y-Nd (ZE21B) alloy modified with the functional coating exhibited moderate surface hydrophilicity and enhanced corrosion resistance. The favourable hemocompatibility of ZE21B alloy with the functional coating was confirmed by the in vitro blood experiments. Moreover, the modified ZE21B alloy could selectively promote the adhesion, proliferation, and migration of endothelial cells (ECs), but suppress these behaviors of smooth muscle cells (SMCs). Furthermore, the modified ZE21B alloy wires could alleviate intimal hyperplasia, enhance corrosion resistance and re-endothelialization in vivo transplantation experiment. These results collectively demonstrated that the functional coating improved the corrosion resistance and biocompatibility of ZE21B alloy. This functional coating provides new insight into the design and development of novel biodegradable stents for biomedical engineering. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) alloys are promising materials for cardiovascular stent applications due to their good biocompatibility and biodegradability. However, in vitro and in vivo corrosion tests reveal that Mg alloy stents suffer from a rapid corrosion rate and severe localized corrosion, which is limiting their widespread application. To solve the problem of uneven degradation of stents, a HTHE (long-time and high-temperature heat treatment, large-reduction-ratio hot extrusion) process is used to manufacture Mg-Zn-Y-Nd alloy microtubes in this study. The heat treatment is to dissolve alloying elements and reduce the size of SPPs, and the hot extrusion is to acquire fine-grained and strongly textured microtubes. The microstructural characterization shows that coarse second phases in as-cast alloy are refined and uniformly distributed in matrix of microtubes. After hot extrusion, microtubes show strong texture with basal plain oriented parallel to the longitudinal section (LS). The corrosion testing indicates that severe localized corrosion occurs on the cross section (CS) while localized corrosion is alleviated on the LS. Based on the different corrosion properties of the LS and CS, HTHEed microtubes are promising for solving the problems of rapid corrosion rate and severe localized corrosion of Mg alloy stents. [ABSTRACT FROM AUTHOR]

Malaria still threatens global health seriously today. While the current discoveries of antimalarials are almost totally focused on single mode-of-action inhibitors, multi-targeting inhibitors are highly desired to overcome the increasingly serious drug resistance. Here, we performed a structure-based drug design on mitochondrial respiratory chain of Plasmodium falciparum and identified an extremely potent molecule, RYL-581, which binds to multiple protein binding sites of P. falciparum simultaneously (allosteric site of type II NADH dehydrogenase, Q o and Q i sites of cytochrome bc 1). Antimalarials with such multiple targeting mechanism of action have never been reported before. RYL-581 kills various drug-resistant strains in vitro and shows good solubility as well as in vivo activity. This structure-based strategy for designing RYL-581 from starting compound may be helpful for other medicinal chemistry projects in the future, especially for drug discovery on membrane-associated targets. A highly potent antimalarial compound, RYL-581, has a potential multi-targeting mechanism of action by simultaneously binding to three pockets (allosteric site of Pf NDH2, Q o and Q i sites of Pf bc 1). [Display omitted] [ABSTRACT FROM AUTHOR]

Magnesium alloys have narrow available slip result from close-packed hexagonal structure that limit their processing properties. In the recent work, the Mg-2Zn-0.46Y-0.5Nd, as materials for degradable stents, was applied to produce as-extruded micro-tube with an outer diameter of 3.0 mm and a wall thickness of 0.35 mm by hot extrusion with an extrusion ratio of 105:1 at 653 K and rapid cooling. The fine microstructure of the dynamic recrystallization of as-extruded micro-tube could be preserved by rapid cooling such as water-cooled, resulting in more excellent mechanical properties relative to air-cooled micro-tube. The addition of rare earth elements Y and Nd results in continuous dynamic recrystallization dominated the dynamic recrystallization mechanism. During the hot extrusion process, the activation of the non-basal slip system, especially the pyramidal 〈 c + a 〉 slip, could significantly weaken the texture strength, and the as-extruded micro-tube exhibits weak "RE" texture components 〈 01 1 ¯ 1 〉 ∥ ED and 〈 1 ¯ 2 1 ¯ 1 〉 ∥ ED. Hence, the magnesium alloy micro-tube prepared by the rapid cooling has fine microstructure and weak texture, which is favorable for further process and governance. [ABSTRACT FROM AUTHOR]

Magnesium alloys were considered to be used as biodegradable implants due to their biocompatibility, biodegradability and nontoxicity. However, under the simultaneous action of corrosive environment and mechanical loading in human body, magnesium alloys are easy to be affected by corrosion fatigue and stress corrosion cracking. In this work, the fatigue behavior of the extruded Mg–Zn–Y–Nd alloy used for vascular stents was studied both in air and in simulated body fluid (SBF). It was revealed that the fatigue limit of as-extruded Mg–Zn–Y–Nd alloy in air is about 65 MPa at 107 cycles, while there is no limit in SBF and shows a linear relationship between the fatigue life and stress amplitudes. The fatigue crack source in air was formed by the inclusions and defects. However, the stress corrosion and hydrogen embrittlement are the main reasons for the formation of the fatigue initial crack source in SBF. [ABSTRACT FROM AUTHOR]

Selective catalytic reduction (SCR) has been extensively employed in industries for the removal of NO x while it is still a challenge to develop novel low-temperature catalysts. The redox and acid sites on the catalyst are often preconditions that cooperate in the SCR reaction. In this study, a series of MnO x supported on MgAl 2 O 4 spinel catalysts (denoted as Mn/MAS) were successfully prepared by incipient wetness impregnation method for low-temperature SCR of NO x with ammonia. The effects of the calcination temperature of MAS support and Mn loading on catalyst structure and performance were examined. The Mn0.12/MAS-700 catalyst showed the best low-temperature denitrification performance, with more than 80% conversion of NO at 150–300 °C and higher than 60% N 2 selectivity. Moreover, the denitrification efficiency remained at nearly 90% in the presence of H 2 O. The physicochemical properties of the catalysts were determined using various characterization methods, and the corresponding results found that the higher concentration of Mn4+ and surface chemisorption oxygen enhanced the low-temperature activity of the catalysts. The addition of Mn species increased the surface acidity of weak acid centers which promoted the catalyst activity. In situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) revealed that the Eley-Rideal mechanism was introduced mainly at 100 °C on the Mn0.12/MAS-700 catalyst. This work provides new inspiration into the effect of Mn species, and the synergistic role of active components Mn and MAS support in the SCR reaction. [Display omitted] • The MnO x supported on Mg-Al spinel exhibited superior low-temperature activity and N 2 selectivity. • The optimal catalyst Mn0.12/MAS-700 showed excellent H 2 O resistance. • The balance of redox capacity and acid sites was considered as crucial factor. • The Eley-Rideal mechanism dominated in the SCR reaction. [ABSTRACT FROM AUTHOR]

Abstract This paper explores the phenomenon of conflict in tourism development in rural China. Four cases were selected and analyzed as part of this exploration. The study identified eight major conflict issues: land expropriation, ticket revenue distribution, vending rights, tourism management rights, house demolition, house building, entry restrictions, and village elections. The conflict evolution process indicates that these issues are dynamic and connected rather than static and isolated. Local government was found to be the most important conflicting party for local people due to its authority and economic interests in tourism development. In addition, an often-ignored conflicting party, villagers' committees, was found to have limitations in maintaining local people's interests. The findings of this study shed light on this complicated and sensitive tourism conflict phenomenon in rural China. A couple of practical implications for local authorities and UNESCO are outlined at the end of the paper. Highlights • Eight major conflict issues were identified. • Conflict issues are dynamic and connected rather than static and isolated. • Local government was found to be the most important conflicting party with local people. • Villagers' committees are an often-ignored party in conflicts during tourism development. • Villagers' committees were found to have limitations in maintaining local people's interests. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO 2 ) is a major greenhouse gas, and it is also an energy source that can be utilized. This paper describes a new technology designed to increase the permeability of coal seams using the phase energy of CO 2 . The technology, named as liquid carbon dioxide phase change fracturing technology, is classified as physical blasting. The kernel of this technology is the blasting system, which consists of release tube containing release holes, cutting plate, liquid storage tube containing heating pipe, guide tube and detonator following the order from the top to the bottom. By starting the detonator, special chemicals in the heating pipe begin to react and a lot of heats then are released instantly to heat the liquid carbon dioxide in liquid storage tube. This process brought about the phase change of carbon dioxide and then caused the dramatically expansion of the volume of carbon dioxide. When the pressure of carbon dioxide in the liquid storage tube exceeds the strength of the cutting plate, the cutting plate is damaged and high pressure carbon dioxide enters the release tube and acts on the coal body. The sphere of influence of this technology in coal seams was studied by the numerical study. Then, a large-scale industrial experiment using the technology was conducted in an underground coal mine in China based on the modeling results. Application of this technology could not only improve the efficiency of coal seam gas extraction but could also turn carbon dioxide into energy to improve energy efficiency. [ABSTRACT FROM AUTHOR]

In this study, a series of praseodymium oxides (Pr 6 O 11) was developed by CTAB-assisted coprecipitation method. The praseodymium oxides were deeply characterized by XRD, N 2 adsorption, SEM, HR-TEM, H 2 -TPR, soot-TPR, NO-TPO and in situ DRIFTS, and tested for soot combustion in absence/presence of NO atmospheres under tight/loose contact conditions. As a non-noble metal and single element oxide, the Pr 6 O 11 catalysts exhibited excellent catalytic performances for both soot oxidation (T 10 = 341 ℃, T 50 = 395 ℃) in O 2 and NO x adsorption (NAC, 906 μ mol/g) at low temperature. It was believed that the relatively large surface area, strong NO oxidation ability and high intrinsic activity contributed to the superior performances. A promoting effect on soot oxidation was found when NO introduced, which was ascribed to the NO x -assisted mechanism. The in situ DRIFTS was used to explore the possible mechanism in the soot oxidation reaction process. The carboxyl was detected over Pr 6 O 11 and was speculated as carbon-oxygen intermediate in soot oxidation. • Praseodymium oxides (Pr 6 O 11) nanorods were synthesized by a CTAB-assisted coprecipitation method. • The as-prepared Pr 6 O 11 nanocatalysts exhibited excellent soot removal ability and NOx adsorption capacity. • Large surface area, high reactivity of oxygen species and strong NO oxidation ability contributed to the good performances. • The "nitrite route" pathway was speculated in NOx adsorption. • The intermediate species (carboxyl) were detected in soot oxidation process. [ABSTRACT FROM AUTHOR]

This study aims to explore the logic of peasant resistance to tourism. Case-oriented qualitative research was adopted, with two tourist villages selected as case studies. The study found petitioning and road blocking are two resistance methods often used by peasants. The use of physically vulnerable peasants and the behaviour of kneeling down are two tactics of peasant resistance. Lawsuits are rarely adopted due to their limitations. The logic of peasant resistance is the result of long-term practice based on a comprehensive consideration of perceived effectiveness, economy, risk perception, and trust propensity. The findings of this study shed some light on the understanding of peasant resistance to tourism, as well as contribute to the development of resistance theory. • The logic of peasant resistance to tourism was explored. • Petitioning and road blocking are often used by peasants. • The use of physically vulnerable people and the behaviour of kneeling down are two tactics of peasant resistance. • Lawsuits are rarely adopted by peasants due to their limitations. [ABSTRACT FROM AUTHOR]

Protective coal layer mining with pressure-relief gas extraction from the protected coal layer is an effective and economical way of controlling coal and gas outbursts in underground mines. According to a field test of the deformation of the protected coal layer in the Qinglong coal mine, during the mining of the protective coal layer, the floor of the protective coal layer can be divided into five areas in the horizontal direction: the original stress area, the stress concentration area, the stress relaxed area, the stress recovery area, and the recompaction area. From coal bed methane (CBM) extraction with pressure relief, the floor strata can also be divided into five areas: the original gas flow area, the gas flow reduction area, the initial pressure relief area with increasing permeability and flow, the full pressure relief area with high permeability and flow, and the pressure recovery area with decreasing permeability and flow. Mining of a protective coal layer will result in the breakage and movement of the overlying strata as well as floor heaves in the floor strata. In these unloaded coal strata, relieving the stress leads to the production of new cracks, which increases the permeability. The coal deformation and gas desorption are remarkable in the protected coal seam. The maximum dilation and dilation rate were 13 mm and 4.19‰, respectively. The gas flow and permeability increased significantly. The maximum natural emission flow and permeability reached 0.194 m³/min and 19.75 m 2 /MPa 2 .d respectively, There were 27- and 42-fold increases in permeability, which indicated that the pressure relief in this region was complete and that fractures in the coal body developed. This emission is conducive to CBM migration and extraction. [ABSTRACT FROM AUTHOR]

Enhanced coal bed methane recovery (ECBM) displacement simulation experiments are a direct way to research on the gas displacement process. We carried out two sets of ECBM experiments by injecting pure N 2 and CO 2 through four large parallel specimens (300 × 50 × 50 mm coal briquette). In the first experiment (N 2 -ECBM), pure N 2 is injected at different pressures to a coal briquette saturated with CH 4 , in the second experiment (CO 2 -ECBM), pure CO 2 is injected at the same injection pressures and various permeability to the same coal briquette outgassed and resaturated with CH 4 . The gas composition and outflow rate were measured with time. In order to master the displacement process, we employed a one-dimensional, two-phase (gas and solid) model. They are in accordance with our experimental results. Coal seam permeability significantly affects the effect of CO 2 or N 2 flooding CH 4 . Under the same conditions, N 2 appears in the outlet in advance than CO 2 . But the N 2 displacement time (CH 4 is completely displaced) is longer than CO 2 , namely CH 4 gas in the coal is completely displaced by CO 2 injection in advance. And flow in the output of CO 2 -ECBM is larger than that of N 2 . Judging from above, CO 2 as injectant is superior to N 2 . [ABSTRACT FROM AUTHOR]

In this study, multiple addition of rare earth (RE) and manganese (Mn) to AZ61 was conducted aiming to find out the influence to corrosion resistance. AZ61 containing different amounts of RE and Mn was investigated by electrochemical measurement in condition of 3.5 wt% NaCl solution at 25 °C. Gravimetric measurement was conducted in 5 wt% salt spray at 35 °C and 3.5 wt% NaCl solution at 25 °C. Samples were characterized by SEM, EDS, OM and XRD. The result shows that with RE addition Al8Mn5 in AZ61 changed into Al10RE2Mn7. The quantity of β phase is reduced significantly. The multiple addition of RE and Mn improved the corrosion resistance of AZ61. When the ratio of Mn and RE is 0.3, alloy has the best property of corrosion resistance. In addition, the composite addition removed the impurity elements in AZ61 especially Fe. [ABSTRACT FROM AUTHOR]

Abstract: Magnesium alloys are promising candidate materials for cardiovascular stents due to their good biocompatibility and degradation properties in the human body. However, in vivo tests also show that improvement in their mechanical properties and corrosion resistance is necessary before wide application. In this study, cyclic extrusion compression (CEC) was used to enhance the mechanical properties and corrosion resistance of Mg–Zn–Y–Nd alloy. The results show that the grain size was greatly refined to 1 m after CEC treatment. The second phase distributed along the grain boundaries with grid shape and nano-sized particles uniformly distributed in grains. The elongation (), ultimate tensile strength (UTS) and yield strength (YS) of the CEC treatment samples were 30.2%, 303 MPa and 185 MPa respectively. The CEC treated samples showed homogeneous corrosion because of the grain refinement and the homogeneous distribution of nano-sized second phase. The corrosion current density of the alloy decreased from 2.810 A/cm to 6.610 A/cm after CEC treatment. Therefore, improved mechanical properties, uniform corrosion and reduced corrosion rate could be achieved by CEC. [Copyright &y& Elsevier]

Abstract: In order to solve the soot emission problems from diesel engines, a series of La2Sn1.8M0.2O7 (M= Sn, Mn, Fe, Co, Cu) oxides with pyrochlore structure were synthesized by co-precipitation, and investigated for soot oxidation with a O2/NO mixture by Temperature-programmed Oxidation. The incorporation of transition metals strongly influences the crystallite size, surface area and redox properties of the catalysts. All the pyrochlore oxides display catalytic soot oxidation activity with nearly 100% selectivity towards CO2. The doped pyrochlores exhibit higher activities than the undoped, which may be related to the enhancement of reducibility. Among them, La2Sn1.8Mn0.2O7 possessed the best activity with Ti = 341°C. The pyrochlore oxides seem to be a novel active alternative for catalytic soot oxidation. [Copyright &y& Elsevier]

Abstract: GPR (Ground penetrating radar) is one kind of the detection technologies with rapid, non-destruction, uninterrupted detection, and high-resolution. GPR can be applied to detect underground holes and loose soil layer and the other baneful anomalies, and therefore is widely applied to hole survey of the subway project in recent years. Based on briefly describing engineering geological background between F station and L station of a subway project in Beijing, this paper gives the arrangement method of GPR survey line in the construction area of shield method, analyzes detection results, verifies an anomaly by spading, determines the distribution range and its characteristic of the hole anomalies. The results showed that three obvious anomalies were detected in the area between F station and L station, and seriously loose soil layer was the cause of No. 1 and No. 3 anomalies, and hole was the cause of No. 2 anomaly. Thereby the anomalies of loose soil layer and hole could be detected accurately by the GPR technology, and then basic data of underground holes could be obtained. On the base of analyzing these data, effective measures could be adopted to avoid the hidden danger, then the safety of subway construction and surrounding environment of the subway project could be ensured. [Copyright &y& Elsevier]

This study explores the reasons for conflict within the tourism sector in rural China. A case-oriented qualitative research method was employed, in which unstructured interviews were used as the primary data collection approach. From the perspective of rural peasant communities this study found three causes for conflict: infringement of peasants' basic rights and interests, economic motivation, and unfair treatment. A deprivation model was then generated as the explanatory tool in which local villagers' experiences of relative deprivation and contractual deprivation were explored. The combination of these two types of deprivation serves to trigger discontent and contributes to conflict. The findings of this study provide valuable insights leading to a better understanding of this complex conflict phenomenon, and they can also help policy makers to better engage communities in relation to conflict reduction and promote sustainable tourism planning and development. • When seen from the perspective of the peasants, three main reasons for the persistent conflict in rural tourism were evident. • A rural tourism-based deprivation model was generated as the explanatory vehicle. • Local villagers experienced relative deprivation and contractual deprivation. • The combination of these two types of deprivation serves to trigger local peasants' discontent and contributes to conflict. [ABSTRACT FROM AUTHOR]