Organic synthesis using (diacetoxyiodo)benzene (DIB): Unexpected and novel oxidation of 3-oxo- butanamides to 2,2-dihalo-N-phenylacetamides

Abstract A novel and reliable method for the direct preparation of 2,2-dihalo-N-phenylacetamides is reported. The key transformation involves the cleavage of a carbon-carbon bond in the presence of DIB and a Lewis acid as the halogen source, and thus this method significantly expands the value of DIB as a unique and powerful tool in chemical synthesis. This protocol not only adds a new aspect to reactions that use other hypervalent iodine reagents but also provides a wide space for the synthesis of disubstituted acetamides. 34

Dynamic change of wheat eco-physiology and implications for establishing high-efficient stable agro-ecosystems under Hg stress

Heavy metal-poisoning exerts the serious influence on crops growth, yield and quality. This research has focused on the impacts of HgCl2 with different concentrations on the dynamic trends of photosynthesis, transpiration and water use efficiency (WUE) by using different wheat varieties as materials. The results showed that under 100 mu M HgCl2 treatment, wheat leaf photosynthetic rate (Pn) and transpiration rate (Tr) exhibited significant changes, but photosynthetic characteristics presented no obvious regularity, and this kind of impact exerted the critical effects on different Hg2+ concentrations. Similar changes sometimes appeared under low concentration and concentrations. WUE changed more regularly, and WUE of each wheat variety tended to drop after Hg2+ treatments, except the individual concentration treatment. This change indicated that HgCl2 treatment changed normal transpiration and photosynthesis, which led to the changes in leaf water use efficiency and related wheat eco-physiological parameters. All these results provide valuable information for establishing high-efficient stable agro-ecosystems in abiotic-stress area. (C) 2014 Elsevier B.V. All rights reserved.Heavy metal-poisoning exerts the serious influence on crops growth, yield and quality. This research has focused on the impacts of HgCl2 with different concentrations on the dynamic trends of photosynthesis, transpiration and water use efficiency (WUE) by using different wheat varieties as materials. The results showed that under 100 mu M HgCl2 treatment, wheat leaf photosynthetic rate (Pn) and transpiration rate (Tr) exhibited significant changes, but photosynthetic characteristics presented no obvious regularity, and this kind of impact exerted the critical effects on different Hg2+ concentrations. Similar changes sometimes appeared under low concentration and concentrations. WUE changed more regularly, and WUE of each wheat variety tended to drop after Hg2+ treatments, except the individual concentration treatment. This change indicated that HgCl2 treatment changed normal transpiration and photosynthesis, which led to the changes in leaf water use efficiency and related wheat eco-physiological parameters. All these results provide valuable information for establishing high-efficient stable agro-ecosystems in abiotic-stress area. (C) 2014 Elsevier B.V. All rights reserved

万焦耳级激光装置的焦斑诊断

In order to evaluate the far;field beam quality of 10 kJ;level laser facility with different off;axis wedged focus lens, by utilizing the methods of the sampling of weak light beams and amplification imaging of splitting beams, the focal spot data of 3ω laser was collected by two 16;bit scientific;grade CCD cameras in the paths of main lobe and side lobe under the conditions of that the lateral magnification coefficient is the same but the intensity attenuation coefficient is different. One CCD obtained main lobe of far;field image, the other acquired its side lobe. The far;field focal spot was reconstructed based on the mathematical model of schlieren method, and the dynamic range is 1 151.71. The influence of CCD dynamic range, relative magnification ratio and system noise on reconstructed image was analyzed. Experimental results show that, the method can achieve a high dynamic range far;field accurate measurement of focal spot, the stitching error is less than one pixel, which meets the requirements of targeting experiments in experimental precision. © 2016, Science Press. All right reserved

Stimuli-responsive molecularly imprinted polymers versatile functional materials.pdf

Phycocyanin was microencapsulated by an extrusion method using alginate and chitosan as coating materials. This work was aimed to optimize the encapsulation process, characterize the physicochemical properties of microcapsules, and evaluate the storage stability and in vitro release performance. The optimum process conditions for preparing microcapsule gained from the single factor experiments were as follows: alginate content 2.5%, ratio of phycocyanin to alginate 1.5:1, content of calcium chloride 2.5%, and chitosan content 2.0%. Phycocyanin/alginate/chitosan microcapsules (PACM) were found to have compact spherical shape with mean diameters of 1.03 mm, whereas phycocyanin/alginate microspheres (PAM) were internal porous spherical appearances with mean diameters of 1.81 mm. Storage stability study showed that encapsulation by alginate and chitosan conferred greater ability to phycocyanin against temperature during storage. In vitro release study revealed that both PAM and PACM could be resistant against acidic environment, and would rapidly release phycocyanin under mild alkali condition. The sustained-release profile of phycocyanin from PACM was superior to that from PAM. (C) 2013 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.Phycocyanin was microencapsulated by an extrusion method using alginate and chitosan as coating materials. This work was aimed to optimize the encapsulation process, characterize the physicochemical properties of microcapsules, and evaluate the storage stability and in vitro release performance. The optimum process conditions for preparing microcapsule gained from the single factor experiments were as follows: alginate content 2.5%, ratio of phycocyanin to alginate 1.5:1, content of calcium chloride 2.5%, and chitosan content 2.0%. Phycocyanin/alginate/chitosan microcapsules (PACM) were found to have compact spherical shape with mean diameters of 1.03 mm, whereas phycocyanin/alginate microspheres (PAM) were internal porous spherical appearances with mean diameters of 1.81 mm. Storage stability study showed that encapsulation by alginate and chitosan conferred greater ability to phycocyanin against temperature during storage. In vitro release study revealed that both PAM and PACM could be resistant against acidic environment, and would rapidly release phycocyanin under mild alkali condition. The sustained-release profile of phycocyanin from PACM was superior to that from PAM. (C) 2013 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved

DISTRIBUTION OF THE POLYPHENOL OXIDASE AND PEROXIDASE IN SEDIMENTS OF SHALLOW LAKES IN THE MIDDLE AND LOWER REACHES OF THE YANGTZE RIVER

The enrichment of organic matter is a striking feature of lake eutrophication. However, distribution of organic matter associated with extracellular enzymes (especially oxidoreductases) in sediments is inadequately studied. In this paper, we described the distributions of oxidoreductase activities in shallow lakes to reveal their roles in the degradation of organic matters in sediments and the effects on eutrophication. The spatial distribution of polyphenol oxidase and peroxidase in sediments of nine lakes (Lake Luhu, Lake Liangzi, Lake Houguan, Lake Niushan, Lake Sanjiao, Like Longyang, Lake Moshui and Lake Yuehu in Hubei Province and Like Taihu in Jiangsu Province) in the middle and lower reaches of the Yangtze River were studied and their correlations with microorganisms were also analyzed. The activities of the two enzymes studied among and within the lakes were unevenly distributed I the sediments with the significantly higher contents of organic matter showed the higher activities, which were observed in the inlet of waste water discharge, the zone with plant residues and the undredged sites. Vertically polyphenol oxidase activities were high at surface sediment with higher organic matter contents. Hence, the organic matters derived from the different sources could induce enzymes. The peroxidase activities varied slightly with increasing sediment depth, a result similar in the dredged and undredged areas, which was probably due to the formation of humic-enzyme complex by the peroxidase and humus after the enzyme induction. There was a significantly positive correlation between the activities of polyphenol oxidase and peroxidase, therefore, the two enzymes coupled in the process of decomposition of organic matters and humification. Bacteria and Actinomyces (not fungi) were dominant species and may be the main producers of the enzymes. In short, the sediment of eutrophic Lakes would respond to the organic matters enrichment by shaping numbers and compositions of microorganisms (Bacteria and Actinomyces) and inducing polyphenol oxidase and peroxidase that oxidize organic matters to produce the humus in the end. At the same time, the enzyme could be stabilized by the formation of humic-enzyme complex. The multiple roles of oxidoreductases in the process of lake eutrophication were discussed in the paper. It may accelerate the process of eutrophication by promoting anaerobic inorganic phosphorus release because of oxygen consumption by polyphenol oxidase, forming loose detritus layer to restrict submerged macrophyte restoration, and affecting division and growth of cell to cause algae bloom. Oil the other hand, it may combat eutrophication process through immobilizing nutrient substances such as amino acids and polysaccharides by humus and inhibiting activity of alkaline phosphatase and nitrification, thereby, it delaying phosphorus and nitrogen cycling. Meanwhile, the formation of humic-enzyme complex may sustain the activities mentioned above. In conclusion, the process of enzymatic decomposition of organic matter in lake sediment is complicated, and the underlying mechanisms should be studied further more