Correction of the toxicity control for stabilizer in studies of the silver nanoparticle effect on Junkat cells

С помощью тетразолиевого теста (МТТ) определяли токсичность для клеток Jurkat анионного ПАВ (АОТ), используемого в качестве стабилизатора наночастиц серебра (НЧС). Целью работы была проверка правильности контроля токсичности стабилизатора по его раствору в воде с концентрацией, равной таковой в растворе НЧС. Сравнивали жизнеспособность клеток после инкубации с одинаковыми разведениями исходного раствора АОТ в дистиллированной воде и в модельном растворе нитрата калия с той же ионной силой, что и в опытном растворе наночастиц. Показано, что токсичность АОТ увеличивается при увеличении ионной силы исходного раствора, что может быть обусловлено изменением соотношения молекул и мицелл этого ПАВ. Сделан вывод, что контроль токсичности заряженного ПАВ, используемого в качестве стабилизатора наночастиц, следует проводить с учетом различия его критической концентрации мицеллообразования в воде и в растворе наночастиц. Toxic effect of anionic surfactant (AOT) used as stabilizer of silver nanoparticles (AgNPs) was determined on Jurkat cells by means of tetrazolium salt (MTT) assay. The purpose was to check the validity of the control of stabilizer toxicity by using its water solution with concentration equal to that in AgNPs solution. Cell viability was compared after the incubation with equal dilutions of AOT stock solutions in water and in model potassium nitrate solution with ionic strength equal to that in AgNPs solution. It is shown that AOT toxicity increases with the increase of ionic strength of the stock solution, presumably because of the change of monomer/micelle relation of this surfactant. The conclusion is that, for the correct control of the cytotoxicity of charged surfactant used as nanoparticle stabilizer one should consider the difference in its critical micelle concentration between water and nanoparticle solution.

Investigation of Inhibitor Polyphosphate Properties for Rotating Steel Disk Electrode in Potassium Nitrate Solution

<p>Inhibition properties of a number of glass-like polyphosphates on 65J steel were investigated using the gravimetry and methods potassium nitrate solution polarization curves in a 0,1M (pH=6,05). The possibilities<br />of optimum experimental conditions were considered as well. Basing on the experimental data the inhibition coefficient and protective effect were found. The inhibiting action of polyphosphates, apparently, is due to the formation of inhomogeneous protecting film on the steel surface.</p>

Effects of temperature and pre-germinative treatments on seed germination of Talinum triangulare (Jacq. ) willd (Portulacaceae)

The objective of this study was to evaluate the effects of temperature, substrate and pre-germinative treatments on T. triangulare seeds. Four temperatures (constant 20, 25, 30 °C and alternate 20-30 °C) and two types of seeding (on paper and between paper), with light, were evaluated. The pre-germinative treatments evaluated included: immersion in water (24 hours), immersion in 6% hypochlorite solution (1 hour), immersion in 0.2% potassium nitrate solution (24 hours), immersion in 0.05% gibberellin solution (24 hours) and the control (untreated seeds). The highest germination percentage was observed at the alternate temperatures of 20-30 ºC, but with no significant difference between the substrates at this temperature. Soaking seeds in KNO3 gave the highest percentage germination and germination speed index (GSI), which differed from the other treatments except for soaking in water. Pre-soaking of T. triangulare seeds favors germination and may be done only in pure water, resulting in a more rapid and uniform germination.

Diurnal Leaf Movement Effects on Spray Interception and Glyphosate Efficacy

Time of day at which a herbicide is applied can affect efficacy, and variability may be attributed to leaf angles at application. Spray interception by hemp sesbania (Sesbania exaltata), sicklepod (Senna obtusifolia), and prickly sida (Sida spinosa) under day and night conditions was quantified by measuring interception of a 2-M potassium nitrate solution. Following the night application, interception by prickly sida, hemp sesbania, and sicklepod was reduced 17, 67, and 70%, respectively. In a second study in the greenhouse, glyphosate was applied to hemp sesbania, pitted morningglory (Ipomoea lacunosa), prickly sida, and sicklepod at 6:00 and 11:00 A.M. and 4:00 and 9:00 P.M. Control of all species was dependent on the time of day treated, with night applications generally being less effective.

Effects of Seed Treatments and Planting Depth on Emergence of Sea Buckthorn Species

The influence of seed treatments and planting depth on the percentage of seed emergence of Hippophae rhamnoides L. `Indian-Summer', H. tibetana Schlecht., H. neurocarpa Liu & He, H. salicifolia D. Don, and H. rhamnoides subsp. rhamnoides, sinensis, turkestanica, and mongolica were studied. Surface seeding had higher percentages of seed emergence and more rapid completion of emergence compared to a 1- or 2-cm (0.4- or 0.8-inch) seeding depth. Seeds soaked in water or potassium nitrate solution at room temperature emerged in higher percentages. Average plant height of the eight species and subspecies varied significantly at the end of first growing season.

Adsorption of nitrate, chloride and sulfate by some highly weathered soils from south-wast Queensland

Soil was collected from a number of sites and depths to 300 cm within four great soil groups (krasnozem, red earth, xanthozem, podzolic). Nitrate, chloride and sulfate adsorption were determined at the soil pH. Various soil properties likely to influence the magnitude of adsorption were determined, and their relative importance to adsorption was assessed using stepwise multiple regression. The subsoils of all four soil groups adsorbed nitrate ranging up to 0.47 mmoles/100 g from 0.005 M potassium nitrate solution. The mean adsorption for soil groups decreased in the order krasnozem, xanthozem, red earth and podzolic. Chloride and sulfate adsorption was largely equivalent to that of nitrate. The variations in adsorption between and within great soil groups could be attributed to changes in organic matter, smectite minerals, hydroxy aluminium, surface area and pH.