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101.
102.
A modified glassy carbon (GC) electrode was developed for the amperometric detection of biogenic amines, particularly histamine. The electrode was modified with the co‐enzyme pyrroloquinoline quinone (PQQ) by entrapment during electropolymerziation of pyrrole to form polypyrrole (PPy). This method formed a thin film on the electrode surface possessing very good stability with a shelf‐life exceeding one month without loss of signal. Optimal conditions for the PQQ/PPy electrode were determined and a linear response was found for histamine in phosphate buffer (pH 6) at +550 mV from 40 to 170 mg L?1 with a limit of detection (S/N≥3) of 38 mg L?1. The practical linear range offered by this method suggests ideal use for spoilage detection in fermented foods. 相似文献
103.
Tatiana A. Shmigol Samantha Hammond James B. Phillips James I. Bruce Alexander J. MacRobert Mikhail V. Malakhov Jon P. Golding 《Photochemistry and photobiology》2013,89(1):139-149
Phthalocyanine photosensitizers are effective in anticancer photodynamic therapy (PDT) but suffer from limited solubility, limited cellular uptake and limited selectivity for cancer cells. To improve these characteristics, we synthesized isopropylidene‐protected and partially deprotected tetra β‐glycosylated zinc (II) phthalocyanines and compared their uptake and accumulation kinetics, subcellular localization, in vitro photocytotoxicity and reactive oxygen species generation with those of disulfonated aluminum phthalocyanine. In MCF‐7 cancer cells, one of the compounds, zinc phthalocyanine {4}, demonstrated 10‐fold higher uptake, 5‐fold greater PDT‐induced cellular reactive oxygen species concentration and 2‐fold greater phototoxicity than equimolar (9 μm ) disulfonated aluminum phthalocyanine. Thus, isopropylidene‐protected β‐glycosylation of phthalocyanines provides a simple method of improving the efficacy of PDT. 相似文献
104.
J. Jon Paul Selvam M. Srinivasulu N. Suryakiran V. Suresh S. Malla Reddy 《合成通讯》2013,43(11):1760-1767
A mild and efficient synthesis of bis(indolyl) methanes by the reaction of indoles with various aldehydes at room temperature in the presence of a catalytic amount of a La(NO3)3 · 6H2O afforded the corresponding bis(indolyl) methanes in excellent yields under solvent‐free conditions. 相似文献
105.
106.
Thi Thanh Hanh Nguyen Jong-Hyun Jung Min-Kyu Kim Sangyong Lim Jae-Myoung Choi Byoungsang Chung Do-Won Kim Doman Kim 《Molecules (Basel, Switzerland)》2021,26(7)
The main protease (Mpro) is a major protease having an important role in viral replication of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the novel coronavirus that caused the pandemic of 2020. Here, active Mpro was obtained as a 34.5 kDa protein by overexpression in E. coli BL21 (DE3). The optimal pH and temperature of Mpro were 7.5 and 37 °C, respectively. Mpro displayed a Km value of 16 μM with Dabcyl-KTSAVLQ↓SGFRKME-Edans. Black garlic extract and 49 polyphenols were studied for their inhibitory effects on purified Mpro. The IC50 values were 137 μg/mL for black garlic extract and 9–197 μM for 15 polyphenols. The mixtures of tannic acid with puerarin, daidzein, and/or myricetin enhanced the inhibitory effects on Mpro. The structure–activity relationship of these polyphenols revealed that the hydroxyl group in C3′, C4′, C5′ in the B-ring, C3 in the C-ring, C7 in A-ring, the double bond between C2 and C3 in the C-ring, and glycosylation at C8 in the A-ring contributed to inhibitory effects of flavonoids on Mpro. 相似文献
107.
Casper Jon Steenbjerg Ibsen Bjørn Fridur Mikladal Uffe Bjørnholt Jensen Assoc. Prof. Henrik Birkedal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(49):16112-16120
Three dimensional hierarchical materials are widespread in nature but are difficult to synthesize by using self‐assembly/organization. Here, we employ a gel–liquid interface to obtain centimeter‐long ~100 μm diameter tubes with complex mineral wall structures that grow from the interface into solution. The gel, made from gelatin, is loaded with metal chloride salt, whereas the solution is a high pH anion source. Tubes were obtained with a range of cations (Ca2+, Sr2+, Ba2+, Cu2+, and Zn2+) and anions (CO32? and PO43?). The crystalline phases found in the tube walls corresponded to expectations from solution chemistries and phase solubilities. The growth mechanism is found to be akin to that of chemical gardens. The divalent cations modify the strength of the gelatin gel in a manner that involves not only simple electrostatic screening, but also ion‐specific effects. Thus, tubes were not obtained for those ions and/or concentrations that significantly changed the gel’s mechanical structure. At high Cu2+ loading, for example, vertical convection bands, not Liesegang bands, were observed in the gels. 相似文献
108.
Shuai Wang Jon Hovland Steven Brooks Rune Bakke 《Applied biochemistry and biotechnology》2014,172(2):776-783
The decrease in toxicity of carbon capture reclaimer monoethanolamine (MEA) waste (MEAw) during anaerobic degradation of such waste together with easily degradable organics was investigated. Samples were collected from a bioreactor at steady state with 86 % organic chemical oxygen demand removal at room temperature, which had been running on MEAw for 2 years. The toxicity of the digester effluents were 126, 42 and 10 times lower than that of the MEAw to the tested freshwater trophic groups of Pseudokirchneriella subcapitata, Daphnia magna and embryos of Danio rerio, respectively. The toxicity of the tested taxonomic groups after anaerobic digestion was mainly attributed to the ammonia generated by the degradation of MEAw. 相似文献
109.
110.
In this paper, we considered the representation power of local overlapping histograms for discrete binary signals. We give an algorithm that is linear in signal size and factorial in window size for producing the set of signals, which share a sequence of densely overlapping histograms, and we state the values for the sizes of the number of unique signals for a given set of histograms, as well as give bounds on the number of metameric classes, where a metameric class is a set of signals larger than one, which has the same set of densely overlapping histograms. 相似文献