Field Measurement and Analysis on the Mechanical Response of Asphalt Pavement Using Large-Particle-Size Crushed Stone Base Treated with Fly Ash and Slag Powder.

The mechanical response of asphalt pavement under vehicular loading is an essential reference for crack-resistant pavement design. However, limited research focuses on the mechanical response measurement of asphalt pavement using a large-particle-size crushed stone base treated with fly ash and slag powder. Therefore, two types of asphalt pavements were constructed. The first type of asphalt pavement uses a large-particle-size crushed stone base treated with fly ash and slag powder, where the slag powder uses granulated blast furnace slag powder. The second type uses a conventional cement-stabilized crushed stone base and serves as a reference structure. Firstly, the strain gauges and temperature sensors were installed during the construction of asphalt pavements. Secondly, the mechanical response of the pavement was tested at different speeds and service time conditions. Then, sensitivity analysis and three-factor analysis of variance (ANOVA) were carried out. Finally, the prediction equations were developed. The results show that the longitudinal strain pulse of the asphalt layer exhibited a "compression-tension-compression" characteristic. For the transverse strain pulse of the asphalt layer, the base layer's transverse and longitudinal strain pulses were only shown as "tensile" characteristics. The vehicular speed significantly affected the strain values for the base and asphalt layers, showing a decreasing trend with increasing speed. For the asphalt layer, the strain values showed an increasing trend with increasing temperature; for the base layer, the strain values showed a decreasing trend with increasing service time. The type of base layer had a significant effect on the strain value. Compared with the conventional base layer, the large-particle-size crushed stone base treated with fly ash and slag powder had lower strain at the base layer and a lower position of the asphalt layer, which could better prevent bottom-up fatigue cracking. Finally, the strain prediction model of the pavement under the speed and temperature (service time) was fitted to obtain a model that can predict the mechanical response of the pavement under different operating conditions. The findings of this research can provide a reference for the design of asphalt pavement using a large-particle-size crushed stone base treated with fly ash and slag powder.

Truck platooning reshapes greenhouse gas emissions of the integrated vehicle-road infrastructure system.

Reducing greenhouse gas emissions has turned into a pillar of climate change mitigation. Truck platooning is proposed as a strategy to lower emissions from vehicles on roads. However, the potential interactive impacts of this technology on road infrastructure emissions remain unclear. Here, we evaluate the decarbonization effects of truck platooning on the integrated vehicle-road system at a large-scale road network level, spanning 1457 road sections across North America. We show that truck platooning decreases emissions induced by truck operations, but it degrades faster the durability of road infrastructure and leads to a 27.9% rise in road emissions due to more frequent maintenance work. Overall, truck platooning results in a 5.1% emission reduction of the integrated vehicle-road system. In contrast to the benefits of emission reduction, truck platooning leads to additional financial burdens on car users and transportation agencies, calling for the consideration of tradeoffs between emissions and costs and between agencies and users. Our research provides insights into the potential applications of truck platooning to mitigate climate change.

Long-Term Aging Behavior of Plastic/Styrene Butadiene Rubber (SBR) Composite Modified Bitumen.

The reuse of recycled waste plastics has long been attempted in pavement engineering as bitumen modifier. It was revealed that waste plastics can significantly enhance the high-temperature performance of bitumen and bitumen mixtures. Even so, the application of waste plastics as a bitumen modifier is still not widespread. This is attributable to the generally poor low-temperature performance of plastic-modified bitumen, which often fails to meet specification requirements. For this purpose, styrene butadiene rubber (SBR) was selected to improve the low-temperature performance of plastic-modified bitumen. However, due to the long-term aging process, the composite and structure of the modified bitumen will change, which negatively impacts its performance. The objective of this study is to investigate the long-term aging behavior of plastic/SBR composite-modified bitumen. For this purpose, waste polyethylene was used as a plastic modifier and was mixed with base bitumen and 3% SBR at ratios 4.5%, 6% and 7.5%. The rheological properties and molecular weight distribution of base bitumen, plastic and plastic/SBR-modified bitumen before and after long-term aging were measured. Results show that the incorporation of plastic can improve the complex modulus, rutting factor and percent recovery of bitumen and reduce the non-recoverable creep compliance of the bitumen, indicating the modification process enhances the high-temperature performance of bitumen. The enhancement effect is more pronounced with the increase of plastic content. For modified bitumen with 7.5% plastic modifier, the complex modulus of modified bitumen is increased by 1127.55% compared to base bitumen. The addition of 3% SBR modifier can further improve the high-temperature performance of the modified bitumen. In addition, the modification process also increases the large molecule size percentage (LMSP) and weight average molecular weight of bitumen. Compared with weight average molecular weight, the LMSP correlates well with the rheological properties of modified bitumen. In accordance with the complex modulus, using the LMSP and weight average molecular weight of bitumen before and after aging, the corresponding aging index was calculated. The quantitative results showed that the addition of plastic modifier can improve the aging resistance of bitumen, but the enhancement effect is not as obvious as that of SBR modifier.

Auricular fistula: a review of its clinical manifestations, genetics, and treatments.

Auricular fistula is a common congenital auricular malformation, characterized as a small opening in the skin and a subcutaneous cyst. It can be classified in different ways according to positions of pits and directions of fistula tracts. The term preauricular fistula and variant type of preauricular fistula (postauricular fistula) are used. Auricular fistula prevalence varies in countries and populations, and its actual prevalence is presently unknown. The most accepted and widely cited theory of auricular fistula etiopathogenesis is an incorrect or incomplete fusion of six auricular hillocks that are mesenchymal proliferations. Auricular fistula can occur either sporadically or genetically. The pattern in inherited cases is thought to be incomplete autosomal dominant, with variable expressions, reduced penetrance, and inapparent gender differences. Auricular fistula has several forms and is reported as being a component of many syndromes. In the field of genetics, currently, there is no related review to comprehensively summarize the genetic basis of auricular fistula and related disorders. This article provides a comprehensive review of auricular fistula, especially congenital preauricular fistula, which accounts for the majority of auricular fistula, by summarizing the clinical manifestations, histological and embryological development, genetics, examinations, and treatments, as well as syndromes with auricular fistula.

Discovery and Functional Characterization of a Diverse Diterpene Synthase Family in the Medicinal Herb Isodon lophanthoides Var. gerardiana.

Isodon lophanthoides var. gerardiana (Lamiaceae), also named xihuangcao, is a traditional Chinese medicinal herb that exhibits a broad range of pharmacological activities. Abietane-type diterpenoids are the characteristic constituents of I. lophanthoides, yet their biosynthesis has not been elucidated. Although the aerial parts are the most commonly used organs of I. lophanthoides, metabolite profiling by gas chromatography-mass spectrometry showed the underground parts also contain large amounts of labdane diterpenoids including abietatriene, miltiradiene and ferruginol, which are distinct from the 13-hydroxy-8(14)-abietene detected in the aerial parts. Comparative transcriptome analysis of root and leaf samples identified a diverse diterpene synthase family including 6 copalyl diphosphate synthase (IlCPS1-6) and 5 kaurene synthase-like (IlKSL1-5). Here we report the functional characterization of six of these enzymes using yeast heterologous expression system. Both IlCPS1 and IlCPS3 synthesized (+)-copalyl diphosphate (CPP), in combination with IlKSL1 resulted in miltiradiene, precursor of abietane-type diterpenoids, while coupling with IlKSL5 led to the formation of hydroxylated diterpene scaffold nezukol. Expression profiling and phylogenetic analysis further support the distinct evolutionary relationship and spatial distribution of IlCPS1 and IlCPS3. IlCPS2 converted GGPP into labda-7,13E-dien-15-ol diphosphate. IlCPS6 was identified as ent-CPS, indicating a role in gibberellin metabolism. We further identified a single residue that determined the water addition of nezukol synthase IlKSL5. Substitution of alanine 513 with isoleucine completely altered the product outcome from hydroxylated nezukol to isopimara-7,15-diene. Together, these findings elucidated the early steps of bioactive abietane-type diterpenoid biosynthesis in I. lophanthoides and the catalytic mechanism of nezukol synthase.

Molecular authentication of Tetrastigma hemsleyanum from its adulterant species using ISSR, CAPS, and ITS2 barcode.

Tetrastigma hemsleyanum is a rare and endangered herb, which is commercialized as the resource of anti-cancer drugs. Wild T. hemsleyanum plants are on the verge of extinction recently, there are increasing numbers of counterfeits on the market. In the present study, inter-simple sequence repeat (ISSR), Cleaved amplified polymorphic sequence (CAPS), and the internal transcribed spacer region II (ITS2) barcode were used for the first time for the authentication of T. hemsleyanum from its commonly counterfeits. ISSR analysis suggested that it was a useful method for distinguishing T. hemsleyanum from its adulterants of different genus. However, it was insufficient to distinguish T. hemsleyanum from those adulterants of the same genus. ITS2 of T. hemsleyanum and the commonly counterfeits were amplified and sequenced. The Neighbor-Joining tree constructed from the ITS2 sequences showed that T. hemsleyanum was clearly differentiated from all counterfeits samples. A mutation site in the ITS2 region of T. hemsleyanum had been found which could be recognized by the restriction endonuclease NcoI. T. hemsleyanum could be readily distinguished from counterfeits as the PCR products from T. hemsleyanum could be digested sufficiently by NcoI, while the PCR products from counterfeits could not be digested. The results indicated that CAPS and ITS2 barcode methods provided effective and accurate identification of T. hemsleyanum from all its adulterants, while ISSR could only distinguish T. hemsleyanum from its adulterants of different genus. The CAPS method developed in the present study will serve as a reliable tool for safe and effective use of T. hemsleyanum in the clinic application. It will also play an important role for the identification, management and conservation of this endangered species.