This work is focused on the laser ablation synthesis of Cu/Ag nanostructures in aqueous solution of acetic acid containing chitosan as capping agent. A two step process taking place in a flowing cell using femtosecond laser pulses was developed to consecutively ablate each metal. As-prepared nanomaterials were morphologically and spectroscopically characterized by transmission electron microscopy, UV-VIS and X-ray photoelectron spectroscopy. Application of Cu/Ag nanomaterials is envisaged as antibacterial materials for food packaging. and Článek se zaměřuje na syntézu Cu/Ag nanostruktur laserovou ablací ve vodném roztoku kyseliny octové obsahujícím chitosan, který plní funkci stabilizačního media. Dvoukroková ablace, probíhající v průtokové cele za použití femtosekundových laserových pulsů, byla navržena tak, aby byla umožněna následná ablace kovů. Takto připravené nanomateriály byly morfologicky a spektroskopicky charakterizovány pomocí transmisní elektronové mikroskopie, UV-VIS a fotoelektronové spektroskopie. Jako případné aplikace Cu/Ag nanostruktur lze uvést antibakteriální obalové materiály potravin.
Genotypic variations were observed among 6 variants and an indigenous one as a control. An efficient genotype OCD(L) of Ocimum sanctum had the greatest content of chlorophylls [2.15 g kg-1(FM)], Chl a/b ratio of 1.86, net photosynthetic rate of 0.72 mg(CO2) m-2 s-1, and 1.56 % oil formation. Methyl chavicol formed 50.31 % of total oil in OSP-6 genotype, which had also maximum peroxidase activity [ΔOD 2.4 mg-1(protein)] and maximum production of eugenol (30.44 % of total oil). We found an oxido-reducible reaction of peroxidase and high bands of peroxidase isoenzymes in this OSP-6 genotype for the formation of monoterpene essential oil(s) and possibly the major constituents of eugenol through the high production of photosynthates. and A. Misra ... [et al.].
We summarize the contemporary understanding of the effects of metal stress on various photosynthetic processes in photoautotrophic organisms and of the defence strategies employed by these organisms to avoid such stress. Cadmium is in the centre of interest of this review, as a non-essential element and important environmental pollutant, but Al, Pb, Hg, As, Cu, and Zn are also considered. Toxic metal ions pollute the environment through anthropogenic activities and affect the quality of plant crop. They represent one of the main abiotic stress factors influencing the health of plants and, as a secondary effect, of animals including man. The review summarizes the generally accepted answers to the questions: How do the toxic metal ions enter the photosynthetic organisms? How are they accumulated in plants? Which mechanisms do plants develop to tolerate metal stress and protect themselves? and T. Kučera, H. Horáková, A. Šonská.
Culturing geranium at different doses of Zn from 0-1.0 g m-3 (Zn0 to Zn1.000) revealed that Zn is an antioxidant promoter, apart from its micronutrient essentiality. Zn0.250 was the critical concentration for maximum content (0.21 %) of total essential monoterpene oil(s). At Zn0.005-Zn0.250, net photosynthetic rate, and contents of chlorophyll and essential monoterpene oil(s) were affected. The maximum peroxidase activity was obtained at Zn0.250, with the production of biomolecule geraniol. We found an oxido-reducible reaction of Zn in the formation of monoterpene essential oil(s) and possibly major constituents of geraniol. and A. Misra ... [et al.].