O,OЈ-diallyl bisphenol A (DBA) and N,NЈ-diallyl p-phenyl diamine (DPD)were used for the reactive diluents of 4,4Ј-bismaleimidodiphenol methane (BDM). The objective was to obtain a modified BDM resin system suitable for resin transfer molding (RTM) process to prepare the advanced composites. The processing behavior was determined by time-temperature-viscosity curves, gel characteristics, and differential scanning calorimetry (DSC). The injection temperature of the resin system in RTM could be 80°C, at which its apparent viscosity was only 0.31 Pa/s, and the apparent viscosity was still less than 1.00 Pa/s after the resin was held at 80°C for 16 h. The gel time test result indicated that at low temperatures, the reactivity of the resin system is low, whereas at high temperatures, the resin could cure very fast, which was beneficial to RTM. The postcure of the cured resin at a given temperature was necessary because the resin had a wide and flat cure exothermic peak, observed by DSC curve. The cured resin displayed both high heat and hot/wet resistance and high mechanical properties, especially tensile strength, tensile modulus, and flexural strength at room temperature, which reached 96.2 MPa, 4.8 GPa, and 121.4 MPa, respectively.

Our results provide a framework for future dissection of the function of the emerging zmP4H family and suggest that AS might have an important role in the regulation of the expression profile of this gene family under waterlogging stress.

Wingless‐type MMTV integration site family member 5B (Wnt5b) regulates life activities such as cell proliferation, tissue morphogenesis and embryo development. We investigated the role of Wnt5b in sex differentiation in Pelodiscus sinensis by analyzing its expression in diverse tissues and embryonic gonads using quantitative reverse transcription PCR (qRT‐PCR). Moreover, Wnt5b expression in gonads of P. sinensis embryos treated with three concentrations of a Wnt agonist was also measured. Sequence alignment indicated that P. sinensis Wnt5b (psWnt5b) protein shared a high sequence similarity with that of Trachemys scripta elegans. Wnt5b gene was highly expressed in embryonic gonads at stages 14–16, but the expression level decreased significantly at stage 17, and Wnt5b expression at stage 14 was significantly higher in female gonads than that in male gonads. Wnt5b had significantly higher expression level in the ovaries than in other tissues. Wnt agonists (5 μg/μl) significantly affected the expression of Wnt5b in male and female embryonic gonads. After Wnt agonists was injected, the expression level of the Wnt5b increased firstly and then decreased overtime. The results suggested that Wnt5b may play a potential important role in gonad development of P. sinensis during the early embryonic stages.

ABSTRACT:A modified bismaleimide (BMI) resin system for resin transfer molding was prepared by using o,oЈ-diallyl bisphenol A ether and 1,4-diallyl phenyl ether as reactive diluents for BMI. The processing behavior was studied through time-temperatureviscosity curves, gel characteristics, and differential scanning calorimetry. The results indicate that the injection temperature can be 80°C, at which its apparent viscosity is only 0.30 Pa ⅐ s. Moreover, after it had been maintained at 80°C for 15 h, the apparent viscosity was still less than 1.00 Pa ⅐ s. The cured resin had remarkable heat resistance, hot/wet resistance, and mechanical properties. The heat stability and mechanical properties of the composite based on this resin system and woven glass cloth are also discussed. For short beam shear strength, in tests at 150 and 180°C, 90 and 65% of the original room temperature strength was retained.

The COVID-19 pandemic has presented unprecedented disruptions to human society worldwide since late 2019, and lockdown policies in response to the pandemic have directly and drastically decreased human socioeconomic activities. To quantify and assess the extent of the pandemic’s impact on the economy of Hebei Province, China, nighttime light (NTL) data, vegetation information, and provincial quarterly gross domestic product (GDP) data were jointly utilized to estimate the quarterly GDP for prefecture-level cities and county-level cities. Next, an autoregressive integrated moving average model (ARIMA) model was applied to predict the quarterly GDP for 2020 and 2021. Finally, economic recovery intensity (ERI) was used to assess the extent of economic recovery in Hebei Province during the pandemic. The results show that, at the provincial level, the economy of Hebei Province had not yet recovered; at the prefectural and county levels, three prefectures and forty counties were still struggling to restore their economies by the end of 2021, even though these economies, as a whole, were gradually recovering. In addition, the number of new infected cases correlated positively with the urban NTL during the pandemic period, but not during the post-pandemic period. The study results are informative for local government’s strategies and policies for allocating financial resources for urban economic recovery in the short- and long-term.