Evaluation and control of the adhesiveness of cohesive calcium carbonate particles at high temperatures

Understanding the adhesiveness of fine particulate materials at high temperatures is important to achieving the stable, economical operation of various industrial systems. In the present research, two types of calcium carbonate (CaCO3) particles having different mean particle sizes (often used as heat carriers in energy systems) were evaluated. The tensile strengths of beds of these materials were determined at various temperatures by tensile strength measurement tester. The adhesiveness was found to increase greatly at 500 °C even without chemical reactions or sintering, and X-ray diffraction analyses showed thermal expansion of the CaCO3 crystals at 500 °C. Pure alumina (Al2O3) and silica (SiO2) microparticles did not exhibit the same pronounced increases in tensile strength or crystal expansion at this same temperature. Because the surface distances between these primary particles were presumably small, it is proposed that van der Waals forces between the particles greatly increased at high temperatures. The addition of Al2O3 nanoparticles to the CaCO3 decreased the tensile strengths of the powder beds both at ambient temperature and at 500 °C. The experimental data confirm that the surface distances between primary particles were increased upon incorporating the nanoparticles, such that the tensile strength decreased during heat treatment

Acetohydroxamic Acid for Peptide Synthesis

The ester derivatives of acetohydroxamic acid md N, N-diacetyl hydroxylamine, N, O-diacetyl hydroxylamine and triacetyl hydroxylamine were assured to be capable of being used as activated esters. At first, evaluation of acyl activating ability was made by reacting the above compounds with amine, and it was shown that all of them worked to yield amides with excellent conversion and that, among them, triacetyy hydroxylamine was most powerfull, where acetylation of amines went through its imide carbonyl group. Furthemore, dipeptide synthesis was found to accomplish without any racemization and in a good yield by use of acetohydroxamic acid. Next syntheses of polymers containing hydroxamic acid structure were carried out by the following routes. (a) methyl methacrylate was copolymerized with N-methacrylobenzyloxyamine and the copolymer obtained was debenzylated, (b) N-methacrylo-N, O-diacetyl hydroxylamine was polymerized, followed by hydrolysis and copolymers with styrene or methyl methacrylate were deacylated. The polymer obtained by route (a) was converted to the activated polymer ester of N-blocked diglycine and removal of the protecting group would provide a method for preparation of cyclic diglycine

Sporolactobacillus inulinusの好気的代謝

Although facultative anaerobe Sporolactobacillus inulinus lacks electron transport chain, this genus grow well under aerobic condition the same as anaerobic culture and final metabolic product on aerobic condition is only acetic acid instead of lactic acid of anaerobic condition. Therefore related enzymes to pyruvate metabolism (lactate dehydrogenase, pyruvate dehydrogenase complex, pyruvate oxidase and pyruvate decarboxylase) and closely enzymes on metabolism of acetylCoA (phosphotrans acetylase, acetate kinase, acetyl-CoA hydrolase, acetaldehyde dehydrogenase, and alcohol dehydrogenase) were measured enzymatic activities respectively. The catabolism from pyruvate to acetic acid under aerobic condition took place by pyruvate dehydrogenase complex, acetyl-CoA phosphotrans acetylase and acetyl kinase. NADH produced from EMP pathway and acetyl-CoA reoxidized by NADH oxidase and H_2O_2 from NADH oxidation scavenged with NADH peroxidase of S. inulinus. So we proposed metabolic pathway of glucose to acetate under aerobic condition of S. inulinus

Elevated glutathione synthesis in leaves contributes to zinc transport from roots to shoots in Arabidopsis

Glutathione (GSH) is a vital compound involved in several plant metabolic pathways. Our previous study indicated that foliar GSH application can increase zinc (Zn) levels in leafy vegetables. The objective of this study was to determine the mode of action of GSH as it relates to Zn transport from roots to shoots. Two types of transgenic Arabidopsis plants with genes for GSH synthesis, including StGCS-GS or AtGSH1 driven by the leaf-specific promoter of chlorophyll a/b-binding protein (pCab3) gene were generated. Both types of transgenic Arabidopsis plants showed significant increases in shoot GSH concentrations compared to the wild type (WT). Monitoring 65Zn movement by positron-emitting tracer imaging system (PETIS) analysis indicated that the 65Zn amount in the shoots of both types of transgenic Arabidopsis plants were higher than that in the WT. GSH concentration in phloem sap was increased significantly in WT with foliar applications of 10 mM GSH (WT-GSH), but not in transgenic Arabidopsis with elevated foliar GSH synthesis. Both types of transgenic Arabidopsis with elevated foliar GSH synthesis and WT-GSH exhibited increased shoot Zn concentrations and Zn translocation ratios. These results suggest that enhancement of endogenous foliar GSH synthesis and exogenous foliar GSH application affect root-to-shoot transport of Zn

Shoot base responds to root-applied glutathione and functions as a critical region to inhibit cadmium translocation from the roots to shoots in oilseed rape (Brassica napus)

Glutathione (GSH) is a tripeptide involved in controlling heavy metal movement in plants. Our previous study showed that GSH, when site-specifically applied to plant roots, inhibits Cd translocation from the roots to shoots in hydroponically cultured oilseed rape ( Brassica napus ) plants. A factor that led to this inhibitory effect was the activation of Cd efflux from root cells. To further investigate the molecular mechanism triggered by root-applied GSH, Cd movement was non-invasively monitored using a positron-emitting tracer imaging system. The Cd absorption and efflux process in the roots were visualized successfully. The effects of GSH on Cd efflux from root cells were estimated by analyzing imaging data. Reanalysis of image data suggested that GSH applied to roots, at the shoot base, activated Cd return. Cutting the shoot base significantly inhibited Cd efflux from root cells. These experimental results demonstrate that the shoot base plays an important role in distributing Cd throughout the plant body. Furthermore, microarray analysis revealed that about 400 genes in the roots responded to root-applied GSH. Among these, there were genes for transporter proteins related to heavy metal movement in plants and proteins involved in the structure modification of cell walls

Effects of enhancing endogenous and exogenous glutathione in roots on cadmium movement in Arabidopsis thaliana

Glutathione (GSH) is a thiol-containing compound involved in many aspects of plant metabolism. In the present study, we investigated how enhancing endogenous and exogenous GSH affects cadmium (Cd) movement and distribution in Arabidopsis plants cultured hydroponically. Transgenic Arabidopsis plants with a strong ability to synthesize GSH in roots were generated by transforming the gene encoding the bifunctional γ-glutamylcysteine synthetase-glutathione synthetase enzyme from Streptococcus thermophiles (StGCS-GS). Enhancing endogenous and exogenous GSH decreased the Cd translocation ratio in different ways. Only exogenous GSH significantly inhibited Cd translocation from roots to shoots in wild-type and transgenic Arabidopsis plants. Our study demonstrated that GSH mainly functions outside root cells to inhibit Cd translocation from roots to shoots