From Castor Oil‐Based Multifunctional Polyols to Waterborne Polyurethanes: Synthesis and Properties

Abstract A novel castor oil‐based multifunctional polyol (CM) is fabricated through mild thiol‐ene photo induced reactions using castor oil (CO) and 1‐thioglycerol (MPD) as building blocks. The effect of the reaction time, molar ratio of thiol to carbon–carbon double bond, and the loadings of photo‐initiator are optimized. The resulting CM is combined with CO and employed as cross‐linkers to prepare castor oil‐based water‐borne polyurethane emulsion with desirable mechanical properties and water resistance. Owing to the incorporation of CM cross‐linker with high hydroxyl value of 371 mg KOH/g (which is 2.27 times higher than that of the CO), the prepared castor oil‐based waterborne polyurethane (CMWPU) possesses compacted 3D network structure with high cross‐linking degree, leading to improved glass transition temperature (45 °C), tensile strength (10.8 MPa), water contact angle (87.4°), and decreased water absorption rate (16.12%) with 20% CM additions. Overall, this work illustrates the feasibility of introducing bio renewable CM combined with CO to develop castor oil‐based WPU employing a sustainable development strategy

Methanogenesis and Acetogenesis in Hydrogenotrophy with Carbonate Minerals: Dependence on Mineral Surface Area, Biofilm Growth, and Microbial Community

The production, storage, and use of hydrogen are anticipated to grow substantially to achieve energy and climate goals. Consequently, microbial communities in many terrestrial and subsurface Earth environments could be exposed to elevated hydrogen concentrations. Hydrogen stimulates metabolic processes that reduce aqueous chemical species, such as bicarbonate or sulfate, that can exchange with solid mineral phases, but the controls on microbial hydrogenotrophy with mineral sources of electron acceptors are not fully understood. Herein, we applied laboratory experiments and biogeochemical modeling to study the response of a natural microbial community to an elevated partial pressure of hydrogen in the presence of carbonate minerals of varying composition, solubility, and size. Experimental incubations and simulation results showed that hydrogen consumption by microbial communities was initially dominated by sulfate reduction and, subsequently, transitioned to acetogenesis and methanogenesis. The rates of acetogenesis and methanogenesis were not correlated with the solubility of carbonate minerals. Instead, we observed strong linear correlations between the rates and surface area of carbonate minerals. Methane and acetate production slowed down in all incubations after about 2 weeks of incubation, although biogeochemical modeling predicted that the metabolic processes were not thermodynamically limited. Electron microscopy and infrared spectroscopy showed that biofilms with diverse microorganisms grew on the carbonates during this period. The methane δ13C value significantly increased, consistent with slower growth at elevated pH. This work highlights that microbial communities form biofilm on carbonate mineral surfaces as a response to hydrogen and that biofilm formation could pose a strong kinetic limitation to hydrogenotrophic metabolism utilizing carbonate minerals

Overexpression of an Incw2 gene in endosperm improved yield-related traits in maize

High yield is an eternal goal for crop breeding. Incw2 protein is the enzyme in the metabolic pathway that mobilizes photoassimilated sucrose into numerous reactions of the developing plant seeds, associated with grain yield. In the research, an Incw2 gene driven by 27 kD zein promoter was specifically over-expressed in the endosperm cells of maize inbred line 18-599R by Agrobacterium-mediated genetic transformation. PCR assay displayed that ten of the regenerated plants were integrated with the target gene. By semi-quantitative RT-PCR and invertase activity analysis, five of them showed significantly higher expression of Incw2 transcripts and enzyme activity compared to the wild type. Among them, line 1 stood out because it possessed the highest level of Incw2 mRNA and enzyme activity. The effects of Incw2 over-expression were reflected in the increased chlorophyll content, improved pho¬tosynthesis and delay of leaf senility. In addition, yield-related traits such as ear length, ear diameter, ear weight, grain weight per ear, and hundred-kernel weight appeared to be improved in three of the transformants compared with the wild type. The grain weight per plant of line1 was increased by nearly 10%. The results collectively indicate that it is potentially practical to enhance kernel yield of maize by overexpression of Incw2 in endosperm

The GARP/MYB-related grape transcription factor AQUILO improves cold tolerance and promotes the accumulation of raffinose family oligosaccharides

Grapevine (Vitis vinifera L.) is a widely cultivated fruit crop whose growth and productivity are greatly affected by low temperatures. On the other hand, wild Vitis species represent valuable genetic resources of natural stress tolerance. We have isolated and characterized a MYB-like gene encoding a putative GARP-type transcription factor from Amur grape (V. amurensis) designated as VaAQUILO. AQUILO (AQ) is induced by cold in both V. amurensis and V. vinifera, and its overexpression results in significantly improved tolerance to cold both in transgenic Arabidopsis and in Amur grape calli. In Arabidopsis, the ectopic expression of VaAQ increased antioxidant enzyme activities and up-regulated reactive oxygen species- (ROS) scavenging-related genes. Comparative mRNA sequencing profiling of 35S:VaAQ Arabidopsis plants suggests that this transcription factor is related to phosphate homeostasis like their Arabidopsis closest homologues: AtHRS1 and AtHHO2. However, when a cold stress is imposed, AQ is tightly associated with the cold-responsive pathway and with the raffinose family oligosaccharides (RFOs), as observed by the up-regulation of galactinol synthase (GoLS) and raffinose synthase genes. Gene co-expression network (GCN) and cis-regulatory element (CRE) analyses in grapevine indicated AQ as potentially regulating VvGoLS genes. Increased RFO content was confirmed in both transgenic Arabidopsis and Amur grape calli overexpressing VaAQ. Taken together, our results imply that AQ improves cold tolerance through promoting the accumulation of osmoprotectants.This work was supported by the Youth Innovation Promotion Association of CAS (2015281), project funded by the China Postdoctoral Science Foundation (2016M601166), Science and Technology Service Network Initiative of CAS (KFJ-STS-ZDTP-025), and Grape Breeding Project of Ningxia (NXNYYZ201502)

The GARP/MYB-related grape transcription factor AQUILO improves cold tolerance and promotes the accumulation of raffinose family oligosaccharides

Grapevine (Vitis vinifera L.) is a widely cultivated fruit crop whose growth and productivity are greatly affected by low temperatures. On the other hand, wild Vitis species represent valuable genetic resources of natural stress tolerance. We have isolated and characterized a MYB-like gene encoding a putative GARP-type transcription factor from Amur grape (V. amurensis) designated as VaAQUILO. AQUILO (AQ) is induced by cold in both V. amurensis and V. vinifera, and its overexpression results in significantly improved tolerance to cold both in transgenic Arabidopsis and in Amur grape calli. In Arabidopsis, the ectopic expression of VaAQ increased antioxidant enzyme activities and up-regulated reactive oxygen species- (ROS) scavenging-related genes. Comparative mRNA sequencing profiling of 35S:VaAQ Arabidopsis plants suggests that this transcription factor is related to phosphate homeostasis like their Arabidopsis closest homologues: AtHRS1 and AtHHO2. However, when a cold stress is imposed, AQ is tightly associated with the cold-responsive pathway and with the raffinose family oligosaccharides (RFOs), as observed by the up-regulation of galactinol synthase (GoLS) and raffinose synthase genes. Gene co-expression network (GCN) and cis-regulatory element (CRE) analyses in grapevine indicated AQ as potentially regulating VvGoLS genes. Increased RFO content was confirmed in both transgenic Arabidopsis and Amur grape calli overexpressing VaAQ. Taken together, our results imply that AQ improves cold tolerance through promoting the accumulation of osmoprotectants

Influencing mechanisms of C content and aging treatment on intergranular corrosion sensitivity of 316 stainless steel weld metals

For analyzing the intergranular corrosion sensitivity of 316 stainless steel weld metals with different C contents, the intergranular corrosion behaviors of the weld metals under as-welded and different as-aged states were evaluated by both the H2SO4–CuSO4 solution corrosion method and the double loop electrochemical potentiokinetic reactivation method, respectively. The results indicate that after long term aging treatment at 550 °C, the δ ferrite in high C weld metal has a higher transformation fraction than that in low C weld metal, which results in a higher intergranular corrosion sensitivity for high C weld metal. However, after the long term aging treatment at 600 °C, the δ ferrite in high C weld metal transforms completely in the early stage aging, and with increasing of the aging time, the desensitization process occurs in the Cr-poor region of high C weld metal, which improves the intergranular corrosion resistance, and results in a higher intergranular corrosion sensitivity for low C weld metal. Therefore, under the service environment of considering the intergranular corrosion performance of the weld metal, the welding material with the appropriate C content should be selected according to the service temperature