Experimental research on the pipe grouting quality is carried out by detecting the concrete test piece with high-frequency antenna array radar. First, the principle of detecting the pipe grouting ...quality with ground-penetrating radar is introduced, and then the pipe grouting situation is researched systematically and completely with three methods, including the oscillogram of a single wave, grey-scale image (2D imaging) and slice image (3D imaging) of antenna array radar, and the research results are verified with an indoor test model. The results show that: Pipe can be positioned precisely with antenna array ground-penetrating radar; for failure of judgment of the grouting fullness of metal pipes and the grouting fullness situation of non-metal pipes, the pipe grouting quality can be identified with the oscillogram of a single wave, grey-scale image (2D) and slice image (3D) respectively; Radar detection 3D image can present the position of a pipe in the structure intuitively and accurately, and, the pipe material and the pipe grouting fullness can be judged by comparing the radar detection 3D image and the 3D slice image.
The major constituents of sand are silica and silicates. The facile and low-cost purification technology of silica from natural sand is of magnificent importance to the industrial applications of ...silicon-based materials. Herein, we report a green, low-cost, and universal method to purify silica from natural sand. Sand from deserts, rivers, and seas is selected as the representative of natural sand. The initial purity of silica is 52.1 wt% for desert sand, 39.3 wt% for river sand, and 35.8 wt% for sea sand. High-purity silica has been successfully separated and purified from natural sand via ball milling, reacting with 30 bar CO
and hydrochloric acid. The purity of silica derived from natural sand reaches >96 wt%. In this work, the mechanism for the purification of silica from natural sand is discussed. This study provides a new method to separate high-purity silica from natural sand without the generation of toxic and harmful substances.
The content created by the users of social networking sites has reached such high levels of quality and variety that it is comparable to that produced by professional agencies. Therefore, ...understanding what types of content users generate and the underlying motivational factors is vital to the success of the sites. The extant research on content generation has primarily focused on the amount of content and on how to encourage participation in content creation, and less attention has been paid to the content itself and how social relations affect the types of content that users upload. This study aims to empirically document the relationship between social ties and the similarities between the types of content that people create online. We collected a large data set from the photo-hosting website Flickr detailing the users' social relations over time in conjunction with their photo-uploading behavior. We found that around the time of the formation of a social tie, members of dyads began to upload more similar photos than they did before that time. After a social tie was formed, this similarity evolved in different ways in different subgroups of dyads. Whereas the similarity between photos uploaded by dyads experiencing notably different popularity levels on the site continued to grow, the dyads of users with similar levels of popularity gradually began to upload less similar photos. In cultural production, individuals appear to present themselves as unique; this feature is more salient when the social contacts are similar in popularity status. Photo-shooting behaviors have been found to exhibit the same patterns. Furthermore, we show that the most divergent uploading behavior is observed when a high-popularity user initiates a tie with a user with lower popularity. We use social psychological motivations to explain these results.
Tick species distribution and prevalence of spotted fever group Rickettsiae (SFGR) in ticks were investigated in Zhejiang Province, China in 2010 and 2011. PCR was used to detect SFGR and positive ...amplicons were sequenced, compared to published sequences and phylogenic analysis was performed using MEGA 4.0. A total of 292 adult ticks of ten species were captured and 7.5 % (22/292) of the ticks were PCR-positive for SFG Rickettsia. The PCR-positive rates were 5.5 % (6/110) for Haemaphysalis longicornis, 3.6 % (1/28) for Amblyomma testudinarium and 16 % (15/94) for Ixodes sinensis, respectively. Phylogenetic analyses of gltA genes detected in ticks indicated that there are two dominating groups of SFGR. Sequences of group one were closely related to Rickettsia monacensis, whereas sequences of group two were closest related to Rickettsia heilongjiangensis and Rickettsia japonica, which are human pathogens. Our findings underline the importance of these ticks in public health surveillance in Zhejiang Province, China.
Advanced carbon materials have played an important function in the field of energy conversion and storage. The green and low-carbon synthesis of elemental carbon with controllable morphology and ...microstructure is the main problem for carbon materials. Herein, we develop a green and low-carbon method to synthesize porous carbon by reacting CO2 with LiAlH4 at low temperatures. The starting reaction temperatures are as low as 142, 121, and 104 °C for LiAlH4 reacting with 1, 30, and 60 bar CO2, respectively. For the elemental carbon, the porosity of elemental carbon gradually decreased, whereas its graphitization degree increased as the CO2 pressure increased from 1 bar to 60 bar. CO2 serves as one of the two reactants and the CO2 pressure can adjust the thermodynamic and kinetic properties of the formation reaction for synthesizing elemental carbon. The mechanism for CO2 pressure-dependent microstructure and morphology of carbon is discussed on the basis of the formation reaction of elemental carbon and gas blowing effect of H2 and CO2. The elemental carbon with different morphology and microstructure exhibits distinct electrochemical lithium storage performance including reversible capacity, rate capability, cycling stability, and Coulombic efficiency, owing to their different lithium storage mechanism. The elemental carbon synthesized at 30 bar CO2 delivers the highest reversible capacity of 506 mAh g−1 after 1000 cycles even at 1.0 A g−1. Advanced energy storage technology based on the green and low-carbon synthesis of carbon materials is a requisite for providing a stable and sustainable energy supply to meet the ever-growing demand for energy.
Biomimetic approach offers numerous opportunities to design therapeutic platforms with enhanced antitumor performance and biocompatibility. Herein we report red blood cell membrane-camouflaged ...nanoparticles (RBC(M(TPC-PTX))) for synergistic chemo- and photodynamic therapy (PDT). Specifically, the inner core is mainly constructed by reactive oxygen species (ROS)-responsive PTX dimer (PTX2-TK) and photosensitizer 5,10,15,20-tetraphenylchlorin (TPC). In vitro experiments show that the prepared RBC(M(TPC-PTX)) is readily taken up into endosomes. Under appropriate light irradiation, the TPC can generate ROS, not only for PDT but also for triggering PTX2-TK cleavage and on-demand PTX release for chemotherapy. In vivo results show that the coating of RBC membrane prolongs blood circulation and improves tumor accumulation. The combination of chemo- and photodynamic therapy enhances anticancer therapeutic activity, and light-triggered drug release reduces systematic toxicity. All these characteristics render the described technology extremely promising for cancer treatment.
The oxygen-dependent feature of most photosensitizers (PSs) and the aggravated hypoxia tumor microenvironment seriously impede the photodynamic therapy (PDT) effectiveness. However, this undesirable ...impediment can be utilized to further trigger the activation of hypoxia-sensitive prodrugs. Moreover, a combined therapy can be used by associating PDT with hypoxia-activated chemotherapy. Herein, a multifunctional Hf–porphyrin nanoscale metal–organic framework (NMOF) platform Hf/tetra(4-carboxyphenyl)porphine (TCPP) has been synthesized, with a high porphyrin loading capacity and a well-ordered coordination array preventing porphyrin self-quenching, thus greatly improving the generation efficiency of reactive oxygen species (ROS), which is helpful for PDT. As-synthesized Hf-TCPP nanoparticles possess more than 50 wt % of TCPP PS content, good crystallization, and a large Brunauer–Emmett–Teller surface for further loading the hypoxia-activated prodrug tirapazamine (TPZ) in a high-loading content. Additionally, subsequent surface modification with a dopamine-derived polymer (DOPA–PIMA–mPEG) significantly improves their dispersibility and structural stability, and the controlled release kinetics of TPZ. Such a nanoplatform can efficiently produce ROS for PDT upon irradiation, and also the depletion of the oxygen could further aggravate the hypoxic environment of tumors to induce the activation of TPZ for achieving an enhanced treatment efficacy. This work demonstrates the great advantages of an NMOF-based platform in antitumor therapies for combined PDT and hypoxia-activated chemotherapy.
Plant root development is mediated by the concerted action of the auxin and cytokinin phytohormones, with cytokinin serving as an antagonist of auxin transport. Here, we identify the AUXIN ...UP-REGULATED F-BOX PROTEIN1 (AUF1) and its potential paralog AUF2 as important positive modifiers of root elongation that tether auxin movements to cytokinin signaling in Arabidopsis (Arabidopsis thaliana). The AUF1 mRNA level in roots is strongly up-regulated by auxin but not by other phytohormones. Whereas the auf1 single and aufl auf1 double mutant roots grow normally without exogenous auxin and respond similarly to the wild type upon auxin application, their growth is hypersensitive to auxin transport inhibitors, with the mutant roots also having reduced basipetal and acropetal auxin transport. The effects of aufl on auxin movements may be mediated in part by the misexpression of several PIN-FORMED (PIN) auxin efflux proteins, which for PIN2 reduces its abundance on the plasma membrane of root cells, aufl roots are also hypersensitive to cytokinin and have increased expression of several components of cytokinin signaling. Kinematic analyses of root growth and localization of the cyclin B mitotic marker showed that AUF1 does not affect root cell division but promotes cytokinin-mediated cell expansion in the elongation/differentiation zone. Epistasis analyses implicate the cytokinin regulator ARR1 or its effector(s) as the target of the SKP1-Cullin1-F Box (SCF) ubiquitin ligases assembled with AUF1/2. Given the wide distribution of AUF1/2-type proteins among land plants, we propose that SCF
AUF1/2
provides additional cross talk between auxin and cytokinin, which modifies auxin distribution and ultimately root elongation.
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