Effect of Secondary Foaming on the Structural Properties of Polyurethane Polishing Pad.

Polyurethane polishing pads are important in chemical mechanical polishing (CMP). Thus, understanding how to decrease the density but increase the porosity is a crucial aspect of improving the efficiency of a polyurethane polishing pad. According to the principle of gas generation by thermal decomposition of sodium bicarbonate and ammonium bicarbonate, polyurethane polishing pad was prepared by a secondary foaming method. The influence of adding such an inorganic foaming agent as an auxiliary foaming agent on the structure, physical properties, and mechanical properties of polyurethane polishing pads was discussed. The results showed that compared with the polyurethane polishing pad without an inorganic foaming agent, the open-pore structure increased, the density decreased, and the porosity and water absorption increased significantly. The highest porosity and material removal rate (MRR) with sodium bicarbonate added was 3.3% higher than those without sodium bicarbonate and 33.8% higher than those without sodium bicarbonate. In addition, the highest porosity and MRR with ammonium bicarbonate were 7.2% higher and 47.8% higher than those without ammonium bicarbonate. Therefore, it was finally concluded that the optimum amount of sodium bicarbonate to be added was 3 wt%, and the optimum amount of ammonium bicarbonate to be added was 1 wt%.

Enhancement of the ammonia synthesis activity of a Cs- or Ba-promoted ruthenium catalyst supported on barium niobate.

Barium niobates with different crystalline structures and morphologies were prepared via a hydrothermal method and applied as a support for a ruthenium catalyst in ammonia synthesis. The sample synthesized with a nominal Ba/Nb ratio = 2.0, having a pure Ba5Nb4O15 crystalline phase and uniform flake-like structure, exhibited the best performance as a support in ammonia synthesis. The flake-like substrate favored the uniform distribution of ruthenium on its surface, which could promote ruthenium to expose more B5 sites. Addition of a Ba- or Cs-promoter enhanced the activity of the Ru/Ba5Nb4O15 catalyst markedly. The highest rate of ammonia synthesis over 2Cs- and 1Ba-4 wt% Ru/Ba5Nb4O15 was 4900 and 3720 (µmol g-1 cat h-1) at 0.1 MPa and 623 K, respectively. Both catalysts were stable during the reaction for 72 h at 673 K and 0.1 MPa. Thus, the synthesized Ba5Nb4O15 is expected to be a promising oxide support for ruthenium catalysts for ammonia synthesis.

Nanostarch-Stimulated Cell Adhesion in 3D Bioprinted Hydrogel Scaffolds for Cell Cultured Meat.

Three-dimensional (3D) bioprinting has great potential in the applications of tissue engineering, including cell culturing meat, because of its versatility and bioimitability. However, existing bio-inks used as edible scaffold materials lack high biocompatibility and mechanical strength to enable cell growth inside. Here, we added starch nanoparticles (SNPs) in a gelatin/sodium alginate (Gel/SA) hydrogel to enhance printing and supporting properties and created a microenvironment for adherent proliferation of piscine satellite cells (PSCs). We demonstrated the biocompatibility of SNPs for cells, with increasing 20.8% cell viability and 36.1% adhesion rate after 5 days of incubation. Transcriptomics analysis showed the mechanisms underlying the effects of SNPs on the adherent behavior of myoblasts. The 1% SNP group had a low gel point and viscosity for shaping with PSCs infusion and had a high cell number and myotube fusion index after cultivation. Furthermore, the formation of 3D muscle tissue with thicker myofibers was shown in the SNP-Gel/SA hydrogel by immunological staining.

Isolation and Identification of Pathogens Causing Blue Mold of Lanzhou Lily during Postharvest Storage and Control of Disease and Mycotoxin Accumulation by Ozone Treatment.

Blue mold (penicilliosis) is a common disease of Lanzhou lily (Lilium davidii var. willmottiae) during postharvest storage, which not only seriously affects the appearance and reduces the quality of lily bulbs, but also leads to the accumulation of mycotoxins in rotten lily tissues, seriously endangering human health. Therefore, it is of great significance to clarify the main isolates causing postharvest blue mold of fresh Lanzhou lily and put forward effective measures to control the disease caused by these pathogens. In this study, pathogens were isolated and purified from the naturally diseased blue-mold tissue of Lanzhou lily, and then morphological and molecular biology techniques were applied to identify the isolates, verify the pathogenicity, determine the disease index and disease incidence, and finally, to analyze the control effect of ozone treatment on the blue mold of lily scale and mycotoxin accumulation. The results indicated that the main isolates causing postharvest blue mold of lily were Talaromyces adpressus, Penicillium gladioli, T. calidominioluteus, and P. polonicum. The pathogenicity test showed that P. gladioli and P. polonicum had a higher disease index than T. calidominioluteus and T. adpressus. Ozone treatment significantly reduced the incidence of disease caused by P. gladioli and P. polonicum, and effectively controlled the accumulation of patulin. This study characterized the main pathogens causing blue mold of postharvest Lanzhou lily during storage, and confirmed ozone application has a significant inhibitory effect on blue mold development and patulin accumulation in Lanzhou lily, which could be helpful in commercially controlling blue mold of postharvest Lanzhou lily during storage.

AcrIIC4 inhibits type II-C Cas9 by preventing R-loop formation.

Anti-CRISPR (Acr) proteins are encoded by phages and other mobile genetic elements and inhibit host CRISPR-Cas immunity using versatile strategies. AcrIIC4 is a broad-spectrum Acr that inhibits the type II-C CRISPR-Cas9 system in several species by an unknown mechanism. Here, we determined a series of structures of Haemophilus parainfluenzae Cas9 (HpaCas9)-sgRNA in complex with AcrIIC4 and/or target DNA, as well as the crystal structure of AcrIIC4 alone. We found that AcrIIC4 resides in the crevice between the REC1 and REC2 domains of HpaCas9, where its extensive interactions restrict the mobility of the REC2 domain and prevent the unwinding of target double-stranded (ds) DNA at the PAM-distal end. Therefore, the full-length guide RNA:target DNA heteroduplex fails to form in the presence of AcrIIC4, preventing Cas9 nuclease activation. Altogether, our structural and biochemical studies illuminate a unique Acr mechanism that allows DNA binding to the Cas9 effector complex but blocks its cleavage by preventing R-loop formation, a key step supporting DNA cleavage by Cas9.

Dynamics changes in physicochemical properties, volatile metabolites, non-volatile metabolites, and physiological functions of barley juice during Bifidobacterium infantis fermentation.

The purpose of this research was to explore the potential of Bifidobacterium infantis fermentation to modify the composition and physiological properties of barley juices. B. infantis JFM12 showed a potent capability to decrease the total sugar contents from 0.39 ± 0.01 mg/mL to 0.35 ± 0.01 mg/mL within 24 h of fermentation. The volatile metabolite profiles were enriched after B. infantis JFM12 fermentation, leading to the changes of 13 aldehydes, 11 ketones, 10 acids, 7 alcohols, and 6 esters. A total of 98 key non-volatile metabolites were identified in the barley juice between before and after B. infantis JFM12 fermentation, including 80 non-volatile metabolites that were remarkably increased and 18 non-volatile metabolites that were remarkably reduced. Furthermore, the antioxidant activities and lipase inhibitory activities of fermented barley juice were higher than those of unfermented barley juice. Overall, B. infantis JFM12 was beneficial in increasing the quality of barley juice.

Structural basis for two metal-ion catalysis of DNA cleavage by Cas12i2.

To understand how the RuvC catalytic domain of Class 2 Cas proteins cleaves DNA, it will be necessary to elucidate the structures of RuvC-containing Cas complexes in their catalytically competent states. Cas12i2 is a Class 2 type V-I CRISPR-Cas endonuclease that cleaves target dsDNA by an unknown mechanism. Here, we report structures of Cas12i2-crRNA-DNA complexes and a Cas12i2-crRNA complex. We reveal the mechanism of DNA recognition and cleavage by Cas12i2, and activation of the RuvC catalytic pocket induced by a conformational change of the Helical-II domain. The seed region (nucleotides 1-8) is dispensable for RuvC activation, but the duplex of the central spacer (nucleotides 9-15) is required. We captured the catalytic state of Cas12i2, with both metal ions and the ssDNA substrate bound in the RuvC catalytic pocket. Together, our studies provide significant insights into the DNA cleavage mechanism by RuvC-containing Cas proteins.

Transcriptional and post-translational activation of AMPKα by oxidative, heat, and cold stresses in the red flour beetle, Tribolium castaneum.

The AMP-activated protein kinase (AMPK) has important roles in the regulation of energy metabolism, and AMPK activity and its regulation have been the focus of relevant investigations. However, functional characterization of AMPK is still limited in insects. In this study, the full-length cDNA coding AMPKα (TcAMPKα) was isolated from the red flour beetle, Tribolium castaneum. The TcAMPKα gene contains an ORF of 1581 bp encoding a protein of 526 amino acid residues, which shared conserved domain structure with Drosophila melanogaster and mammalian orthologs. Exposure of female adults to oxidative, heat, and cold stresses caused an increase in TcAMPKα mRNA expression levels and phosphorylation of Thr-173 in the activation loop. The RNAi-mediated knockdown of TcAMPKα resulted in the increased sensitivity of T. castaneum to oxidative, heat, and cold stresses. These results suggest that stress signals regulate TcAMPKα activity, and TcAMPKα plays an important role in enabling protective mechanisms and processes that confer resistance to environmental stress.

Molecular characterization of class I histone deacetylases and their expression in response to thermal and oxidative stresses in the red flour beetle, Tribolium castaneum.

Reversible acetylation of core histones plays an important role in the epigenetic regulation of gene transcription, and is controlled by the action of histone acetyltransferases (HATs) and histone deacetylases (HDACs). While HDACs have been well studied in Drosophila melanogaster, information from insect pests is still limited. In the current study, we cloned and characterized three class I enzymes, TcHDAC1, TcHDAC 3 and TcHDAC 8, in the red flour beetle, Tribolium castaneum. Expression profiling showed that T. castaneum HDAC genes are expressed in all developmental stages and tissues examined. A dramatic increase of mRNA expression level was observed from prepupae to 1-day-old pupae for all three T. castaneum HDAC genes. Both TcHDAC1 and TcHDAC3 exhibited the highest mRNA expression levels in thorax, whereas TcHDAC8 was highly expressed in fat body. Furthermore, T. castaneum HDAC genes were found to respond to heat, cold and oxidative stresses. While the heat-stress treatment decreased the mRNA expression levels of T. castaneum HDAC genes, their transcripts were induced by paraquat treatment. These results suggest a possible role for class I HDAC genes in the epigenetic regulation of T. castaneum development and stress responses.

Knockdown of the GABA receptor RDL genes decreases abamectin susceptibility in the rice stem borer, Chilo suppressalis.

The γ-aminobutyric acid (GABA) receptor is a primary neurotransmitter receptor in both vertebrate and invertebrate nervous systems. Multiple RDL subunits have been found in insects including the rice stem borer, Chilo suppressalis, however, comparative characterization of duplicated RDL genes in insects is still limited. In this study, comparison of the genomic sequences and the cDNA sequences revealed that both CsRDL1 and CsRDL2 consisted of 10 exons and 9 introns, and their exon-intron boundaries occur in the same position with respect to the coding sequences. Expression profiling showed that both CsRDL1 and CsRDL2 were predominantly expressed in nervous system, and had low expression levels in the gut and integument. The transcript level of CsRDL2 dramatically increased from the prepupae to late pupae and were much higher than that of CsRDL1 in adult stages. Notably, dietary ingestion of dsRDL1 and dsRDL2 significantly decreased the larval susceptibility to abamectin. These results suggest that CsRDL1 and CsRDL2 might play both physiological roles in development and toxicological roles in action of abamectin in C. suppressalis.

Short-term effect of air pollution on asthma patient visits in Shanghai area and assessment of economic costs.

BACKGROUNDS: Shanghai, in China, is one of the highest incidence cities for asthma morbidity. However, few studies have systemically explored the association of ambient air pollutants and asthma patients with economic costs. OBJECTIVES: The study researched the link of short-term ambient air pollutants exposure and asthma patients in Shanghai. Furthermore, the economic cost was also assessed. METHODS: We applied the generalized addictive model (GAM) to analyze the association between ambient air pollutants and asthma patients with economic costs assessment. RESULTS: We investigated a total of 7200 asthma patient visits (inhabitant in Shanghai). A 10 µg m-3 increase in the current day concentrations of SO2, CO, NO2, PM10, O3 and PM2.5 corresponded to increase of 3.79% [95% CI: 0.84%, 6.83%], 0.27% [95% CI: 0.14%, 0.40%], 0.63% [95% CI: - 0.81%, 2.10%], 1.11% [95% CI: 0.38%, 1.85%], 0.23% [95% CI: 0.31%, 078%] and 1.27% [95% CI: 0.29%, 2.26%] in daily asthma patient visits. In economic cost level, the economic cost of asthma patients were attributed to ambient air pollutants (SO2, CO, NO2, PM10, O3 and PM2.5) with 197 million USD losses per year. Among, the economic cost of asthma patient visits were attributed to SO2, CO, NO2, PM10, O3 and PM2.5 with 101.30, 7.46, 17.15, 30.18, 6.39 and 34.50 million USD loss per year, respectively. CONCLUSIONS: Short-term exposure to SO2, CO, NO2, PM10, O3 and PM2.5 were linked to asthma patient visits increase in Shanghai areas. The economic cost of asthma patient visits were attributed to ambient air pollutants (SO2, CO, O3, PM10, NO2 and PM2.5) with 197 million USD losses per year. The study strengthen our fundamental comprehending of impacts of ambient air pollutants on human health and economy burden.

Air pollutants and asthma patient visits: Indication of source influence.

BACKGROUND: Sources of air pollutants are significant factors for adverse health effect. Few current studies explored the linking of sources influence and ambient pollutants to asthma patient visits in Shanghai, China. OBJECTIVES: This study explored the associations between short-term exposures to ambient pollutants and asthma morbidity with terrestrial and marine source influence in Shanghai. METHODS: Generalized additive model (GAM) was used to explore the association of daily patient visits and ambient pollutants. These analyses were calculated in R statistical software in mgcv package. PSCF modeling was used to locate potential source areas contributing to the concentrations of pollutants. RESULTS: We found that per IQR of PM2.5, PM10, NO2, SO2, O3 and CO in terrestrial source were associated with an increase of 6.63% (95% CI: -0.27% to 14%), 6.48% (95% CI: 0.06% to 13.3%), 1.68% (95% CI: -2.68% to 6.24%), 2.81% (95% CI: -1.42% to 7.22%), -0.60% (95% CI: -5.94% to 5.04%) and 16.6% (95% CI: 8.68% to 25.2%), respectively in asthma patient visits. Per IQR of PM2.5, PM10, NO2, SO2, O3 and CO in marine source were associated with an increase of 5.34% (95% CI: 0.42% to 10.5%), 3.84% (95% CI: 0.08% to 7.74%), 3.21% (95% CI: -0.92% to 7.52%), 2.58% (95% CI: -1.02% to 6.30%), 1.42% (95% CI: -3.10% to 6.15%) and 8.81% (95% CI: 2.56% to 15.4%). The PSCF show all of the pollutants except O3 mainly come from terrestrial during observation. We also found that all of the pollutants except NO2 displayed the highest effect in the spring for relative risk of asthma morbidity. CONCLUSIONS: Ambient air pollutants that cause an increase in asthma patient visits, such as PM2.5, PM10, NO2, SO2 and CO are mainly produced from terrestrial sources, while O3 is primarily from marine sources. The association of ambient pollutants and asthma patient visits is closely related with seasons, especially with spring. PM2.5 and CO are major air pollutants increasing the relative risk of asthma patient visits in Shanghai.