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111.
The plasticization by 4-decylaniline (4DA) of a microphase-separated poly(ethyl acrylate) ionomer containing sodium carboxylate groups is examined. Dynamic mechanical thermal analysis, supplemented by differential scanning calorimetry, shows that the matrix and cluster glass transitions (Tg's) in the ionomer are both depressed by ca. 1°C/wt % 4DA; this, in turn, is similar to the Tg depression in the blend of the parent poly(ethyl acrylate) (PEA) with 4DA. There is no evidence of 4DA crystallinity in the blend. Small-angle x-ray scattering (SAXS) measurements show that the ionomer peak increases in intensity and decreases in scattering angle with increasing concentration of 4DA in the blend; the corresponding Bragg spacing, initially at 2.3 nm, increases by ca. 0.04 nm/wt % 4DA. These results, supported by preliminary spectroscopic measurements, are attributed to hydrogen bonding interactions between the amine groups of 4DA and the ester groups in PEA and the ionomer, rendering the blend miscible. It is argued that the uniform distribution of 4DA throughout the material plasticizes both phases of the ionomer by adding free volume; this also accounts for the increase in the characteristic spacing detected by SAXS. 相似文献
112.
Background
Calcium (Ca2+) has recently been shown to selectively increase the activity of monoamine oxidase-A (MAO-A), a mitochondria-bound enzyme that generates peroxyradicals as a natural by-product of the deamination of neurotransmitters such as serotonin. It has also been suggested that increased intracellular free Ca2+ levels as well as MAO-A may be contributing to the oxidative stress associated with Alzheimer disease (AD). 相似文献113.
At the water's edge: nitric acid as a weak acid 总被引:1,自引:0,他引:1
Shamay ES Buch V Parrinello M Richmond GL 《Journal of the American Chemical Society》2007,129(43):12910-12911
114.
Geraldine Merle Morgane Seon‐Lutz Joao Henrique Lopes Jake E. Barralet 《Particle & Particle Systems Characterization》2014,31(10):1091-1096
Several methods have been proposed for capturing the CO2 emitted into the atmosphere by human activity. To date, mainly amine‐based absorption processes are currently among the more promising systems for post‐combustion CO2 capture. Tertiary amine solvents obviate the need for a high solvent regeneration temperature and fast absorption can be achieved with the use of carbonic anhydrase (CA), as an activator. In this study, the capacity of CA immobilization on nanoporous microparticles hierarchically structured to enhance their stability in tertiary amines is investigated. These microstructures allow for an efficient supply and presentation of substrate in the non‐aqueous solvent to the enzyme catalytic center and the particles' large size is attractive to make separation and reuse facile. These hierarchically structured particles conserve 70% of their initial activity after 30 d at 50 °C in amine solvent, whereas the free enzyme shows no activity after 1 h in the same conditions. In this work, we have overcome the technical hurdle linked to the recovery of the biocatalyst after operation thereby reducing costs of the system and importantly these micro‐bioparticles have shown a remarkable increase of the thermal stability of CA in an amine‐based CO2 sequestration solvent as determined by a para‐nitrophenyl acetate assay. 相似文献
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Manojkumar Mahapatra Umasankar Kulandaivelu Philipp Saiko Geraldine Graser Thomas Szekeres Graciela Andrei Robert Snoeck Jan Balzarini Venkatesan Jayaprakash 《Chemical Papers》2013,67(6):650-656
Methyl-2-arylidene hydrazine-carbodithioate has not been of particular interest to researchers even though its metal complexes are extensively reported on due to their biological activity. This study examined the cytostatic and antiviral activity of twelve methyl-2-arylidene hydrazinecarbodithioates reported by many researchers as intermediates for the synthesis of thiosemicarbazides and the preparation of their metal complexes. Compounds IIc, IIi, and IIl with tridentate ligand features were found to have the lowest IC50 value (6.5 μM, ≈ 1 μM, and 0.8 μM, respectively) against HL60 human promyelocytic leukemia cells. They were also most inhibitory to human embryonic lung (HEL) fibroblast proliferation (5.3 μM, 17 μM, and 2.6 μM). Compound IIc and IIl show antiviral activity against wild-type herpes simplex virus (HSV), varicella zoster virus (VZV), and acyclovirresistant HSV; however, these activities were observed at concentrations at which the compounds also markedly inhibit HL60 and HEL cell proliferation. 相似文献
117.