The distress history of a geogrid-reinforced segmental retaining wall (GR-SRW) that was constructed as a highway shoulder, June 2014, using loess backfill in Shaanxi Province, China, is presented. A narrow, arc-shaped pavement crack propagating toward the wall and a vertical open gap between the cover plate and coping were found in September 2014. Improper diagnosis and treatment caused the crack and gap to worsen until June 2016. Consultation, field observations, measurement, drilling, laboratory tests, and internal stability analyses were executed immediately to determine the causes of the distress. Consultation and field observation were executed to obtain the GR-SRW development on November 5th, 2018. The insufficient and differential compaction of the loess backfill likely caused the distress initially found. Water infiltration, fine-grained loess backfill use, and improper diagnosis and treatment worsened the GR-SRW distress from June 2014 to November 2018. Preliminary repair suggestions, including a prestressed anchoring wallboard retaining wall, upswept drainpipes, rammed soil-cement or compacted soil-lime columns, and rebuilding the existing pavement layers, were provided. Lessons learned provide a reference for future construction.
The continuous adoption of artificial intelligence technology (CAAIT) has fully demonstrated its transformative roles in various fields, and it has effectively improved the economic benefits of agriculture in practical applications. However, sustainable agricultural development can only be achieved if economic and environmental benefits are reconciled. Then, it is necessary to explore whether CAAIT can provide valuable environmental benefits. Therefore, this paper uses AMOS 22.0 and SPSS 25.0 software, a hierarchical regression model, and bootstrapping to analyze the survey data of 522 farmers and finds that: (1) CAAIT is positively correlated with the behavior of holders’ farmland quality protection (BHFQP). (2) Social norms (SN) partially mediate the relationship between CAAIT and BHFQP. (3) Green cognition (GC) plays a negative intermediary role in the relationship between CAAIT and SN. (4) GC also moderates the mediating effect of SN in the relationship between CAAIT and BHFQP. This paper attempts to explore whether, how, and when CAAIT can affect BHFQP, providing new empirical research to improve holders’ farmland quality protection behavior.
O(6)-methylguanine-DNA-methyltransferase (MGMT) is a specific DNA revising enzyme transferring alkylated groups from DNA to its cysteine residue to avoid the abnormal twisting of DNA. Therefore, it is one of the drug resistant genes targeted in the treatment of cancer. This study explored the protective effect of MGMT gene transferred into mammalian cells.Mammalian expression vector containing the MGMT gene cloned from human hepatocytes by RT-PCR was constructed and transferred into K562 cells and human peripheral blood mononuclear cells (PBMCs) via liposome, then assayed for gene expression at RNA and protein levels. MTT assay was used to check the drug resistance of cells transfected with MGMT gene.MGMT gene was successfully cloned. Real-time PCR showed that the mRNA expression in gene transfected groups in K562 cell line and PBMC were 13.4 and 4.0 times that of the empty vector transfected groups respectively.of Western blotting showed distinct higher expression of MGMT in gene transfected group than in other two groups. The IC(50) values increased to 7 and 2 times that of the original values respectively in stable transfected K562 cells and transient transfected PBMC.The alkylating resistance of eukaryotic cells is enhanced after being transfected with MGMT gene which protein product performs the protective function, and may provide the reference for the protective model of peripheral blood cells in cancer chemotherapy.
The comfortable housing project for low-income urban residents possess many special characteristics such as large numbers, dispersed distribution, the large-scale of construction, urgent time schedule and strict requirement of high quality. To ensure reasonable period and construction cost, it is also necessary to reform and innovate the way of construction management thinking and working methods. Pre-control measures of construction quality are put with emphasis on transforming passivity supervision into initiative forewarning. Management efficiency of the comfortable housing project can be enhanced. The comfortable housing project for low-income urban residents is built into environmental project taken to develop energy-saving and ground-saving residential in our country. It is a realistic and sharp contradiction that construction enterprises are pursuing profit when indemnificatory housing constructing is weak of profit, and that it is an easily occurred problem that the quality of indemnificatory housing is not security. In this paper, based on the six sigma quality management the Quality Assurance System of indemnificatory housing is put forward, which can be regarded as guidance for construction enterprises.
The measurement of total mercury in flue gas based on an economical aluminum matrix sorbent was developed in this paper. A sorbent trap consisted of three tubes was employed to capture Hg from flue gas. Hg trapped on sorbent was transferred into solution by acid leaching and then detected by CVAAS. Hg adsorbed on sorbent was recovered completely by leaching process. The 87.7% recovery of Hg in flue gas by tube 1 and tube 2 was obtained on the equipment of coal combustion and sampling in lab. In order to evaluate the ability to recover and accurately quantify Hg 0 on the sorbent media, the analytical bias test on tube 3 spiked with Hg 0 was also performed and got the average recovery of 97.1%. Mercury measurements based on this method were conducted for three coal-fired power plants in China. The mercury in coal is distributed into bottom ash, electrostatic precipitator (ESP) ash, wet flue gas desulfurization (WFGD) reactant, and flue gas, and the relative distribution varied depending on factors such as the coal type and the operation conditions of plants. The mercury mass balances of three plants were also calculated which were 91.6%, 77.1%, and 118%, respectively. The reliability of this method was verified by the Ontario Hydro (OH) method either in lab or in field.
Identifying and protecting hotspots of endemism and species richness is crucial for mitigating the global biodiversity crisis. However, our understanding of spatial diversity patterns is far from complete, which severely limits our ability to conserve biodiversity hotspots. Here, we report a comprehensive analysis of amphibian species diversity in China, one of the most species-rich countries on Earth. Our study combines 20 y of field surveys with new molecular analyses of 521 described species and also identifies 100 potential cryptic species. We identify 10 hotspots of amphibian diversity in China, each with exceptional species richness and endemism and with exceptional phylogenetic diversity and phylogenetic endemism (based on a new time-calibrated, species-level phylogeny for Chinese amphibians). These 10 hotspots encompass 59.6% of China’s described amphibian species, 49.0% of cryptic species, and 55.6% of species endemic to China. Only four of these 10 hotspots correspond to previously recognized biodiversity hotspots. The six new hotspots include the Nanling Mountains and other mountain ranges in South China. Among the 186 species in the six new hotspots, only 9.7% are well covered by protected areas and most (88.2%) are exposed to high human impacts. Five of the six new hotspots are under very high human pressure and are in urgent need of protection. We also find that patterns of richness in cryptic species are significantly related to those in described species but are not identical.
Viviparous (live-bearing) vertebrates have evolved repeatedly within otherwise oviparous (egg-laying) clades. Over two-thirds of these changes in vertebrate reproductive parity mode happened in squamate reptiles, where the transition has happened between 98 and 129 times. The transition from oviparity to viviparity requires numerous physiological, morphological, and immunological changes to the female reproductive tract, including eggshell reduction, delayed oviposition, placental development for supply of water and nutrition to the embryo by the mother, enhanced gas exchange, and suppression of maternal immune rejection of the embryo. We performed genomic and transcriptomic analyses of a closely related oviparous–viviparous pair of lizards ( Phrynocephalus przewalskii and Phrynocephalus vlangalii ) to examine these transitions. Expression patterns of maternal oviduct through reproductive development of the egg and embryo differ markedly between the two species. We found changes in expression patterns of appropriate genes that account for each of the major aspects of the oviparity to viviparity transition. In addition, we compared the gene sequences in transcriptomes of four oviparous–viviparous pairs of lizards in different genera ( Phrynocephalus , Eremias , Scincella , and Sphenomorphus ) to look for possible gene convergence at the sequence level. We discovered low levels of convergence in both amino acid replacement and evolutionary rate shift. This suggests that most of the changes that produce the oviparity–viviparity transition are changes in gene expression, so occasional reversals to oviparity from viviparity may not be as difficult to achieve as has been previously suggested.
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