Three plants extracts were used for biosynthesis of Ag nanoparticles (AgNPs). AgNPs nucleation process requires effective reduction agents which secure Ag+ to Ag0 reduction and also stabilizing/capping agents. The UV-vis and TEM observation revealed that the best results were obtained by R. officinalis leaf extract. The strong SPR band peak appeared at the wavelength 418 nm. Synthetized AgNPs were globular, fine (~20 nm), uniform and stabile throughout the experiment. A rapid rate of AgNPs synthesis was also significant and economically advantageous factor. Fine (10-20 nm) and globular nanoparticles were synthetized also by U. dioica leaf extract, but the stability of nanoparticles was not permanent. Despite V. vitis-idaea fruit extract contains a lot of reducing agents, UV-vis did not confirm the presence of AgNPs in solution. Synthetized Ag particles were very unstable, Ag particles agglomerated very fast and clearly indicated sediment was formed.
For the reliable applications of silver nanowires, AgNW, which is used as a conductive transparent film in electronic devices, the isothermal degradation behaviors of AgNW films with and without overcoating were investigated. Accelerated isothermal degradation was performed as a function of temperature, time, and atmosphere. Electrical resistance and optical transmittance were measured and correlated with the microstructural damages, such as formation of oxide particles and fragmentations of AgNW, which were quantitatively determined from the scanning electron micrographs. The overcoating retarded the formation of oxide particles and subsequent fragmentations as well as resulting degradation in electrical resistance without affecting the optical transmittance.
Silver nanoparticles (AgNPs) are widely used in numerous industries and areas of daily life, mainly as antimicrobial agents. The particles size is very important, but still not suffi ciently recognized parameter infl uencing the toxicity of nanosilver. The aim of this study was to investigate the cytotoxic effects of AgNPs with different particle size (~ 10, 40 and 100 nm). The study was conducted on both reproductive and pulmonary cells (CHO-9, 15P-1 and RAW264.7). We tested the effects of AgNPs on cell viability, cell membrane integrity, mitochondrial metabolic activity, lipid peroxidation, total oxidative and antioxidative status of cells and oxidative DNA damage. All kinds of AgNPs showed strong cytotoxic activity at low concentrations (2÷13 μg/ml), and caused an overproduction of reactive oxygen species (ROS) at concentrations lower than cytotoxic ones. The ROS being formed in the cells induced oxidative damage of DNA in alkaline comet assay. The most toxic was AgNPs<10 nm. The results indicate that the silver nanoparticles, especially less than 10 nm, may be harmful to the organisms. Therefore, risk should be considered when using nanosilver preparations and provide appropriate protective measures when they are applied.
Layers of silver particles are used in the studies on pathophysiology and treatment of diseases, both in pre-clinical and clinical conditions. Silver layers can be formed using different techniques and on different substrates. Deposition by magnetron sputtering on glass beads was used in this study. Silver absorption by the body was estimated by calculating the difference in thickness of the silver nanolayer deposited on a bead and measured before and after application of the bead in an animal model of gastrointestinal inflammation. Recommendations for the minimal thickness of silver nanolayer deposited on glass beads were worked out for further studies.
Silver coatings have a very high reflection ability. To avoid their darkening from the hydrogen sulphide in the air, a thin layer of heat-resistant colorless lacquer is applied to the coatings. Silver plating is mainly used in jewelery, optics, electronics and electrical engineering. Depending on their application the thickness of the layer may vary from 2 to 24 μm. It can be done in several ways: chemical, electrochemical, contact, etc. The most common way of silver plating is the electrochemical deposition using cyanide and non-cyanide electrolytes. The cyanide electrolytes produce light, fine crystalline, dense and plastic coatings upon silver-plating. Usually silver coatings are applied with copper or nickel intermediate layer. In order to improve the de-oxidation of the aluminum surface new chemical treatment in acid – alkaline solution was applied. Our previous research shows that the presence of diamond nanoparticles in the electrolyte increase the metal deposition. Samples were prepared from electrolyte containing 10 g/l diamond nanoparticles. Their properties were compared to the properties of reference samples. The diamonds were obtained by detonation synthesis. The aim of this study is to obtain electrochemically deposited silver layer with high density, adhesion and electric conductivity on aluminum alloys substrate. The coatingwas directly plated without intermediate layer. Non-cyanide electrolyte composition and electrochemical parameters were determined in order to produce Ag coatings on Al alloy substrate without intermediate layer. The coating is with good adhesion, density and thickness of 14-23 μm.
Недотыкомка is a symbol-word in the Russian literature of the Silver Age, meaning ubiquitous evil, according to the modernist world view, constituting the nature of existence. In this paper we demonstrate how the translation of this untranslatable word has influenced the perception of a literary work. We focus mainly on the poem Недотыкомка серая… (1905), the title of which in Wiktor Woroszylski’s translation is Niepochwytnica szara… (1971), while in the translation by Włodzimierz Słobodnik – Niedoruszajka szara… (1971) and in the novel Мелкий бес (1905), where this fulfils an important function (in René Śliwowski’s translation of 1973 – the name of this creature is Niedotkniątko). We examine what role the character of niedotykomka has in the discussed novels and we analyze the impact translation strategies have on the image of a fictional universe as well as a lyrical situation (i.e., the change of the feminine grammatical form in the character’s name into a grammatically neuter one).
The extraction of mineral deposits is usually charged with additional taxes or royalty fees that go beyond the general income tax. As a rule, countries prefer stable sources of fiscal revenues based on the volume of raw material extraction, and investors prefer models based on profit tax, i.e. taking operating costs and risks lower than the expected profitability of the project into account. As a rule, too high a burden for the mining sector affects investors’ decisions regarding the introduction of new investments. There are a number of examples where excessive fiscal burdens force investors to move to countries with more favorable tax systems. An analysis of various forms of taxation of mining enterprises around the world has been presented and compared with the system implemented in Poland. Usually, the countries that apply the royalty fee in the mining sector at the same time introduce a number of adaptation mechanisms. This is crucial for new investments due to the fact that they may to some extent compensate for the high costs of transition from the investment to the operational phase. In most cases, several incentive mechanisms are used at the same time, e.g. the accelerated settlement of investment expenditures and the unlimited settlement of losses. The copper and silver mining tax introduced in Poland increased the discounted effective tax rate (ETR) from 38.5% to 89% for the entire investment period, which resulted in a 11-year return on investment, as well as a drop in the internal rate of return (IRR).There are currently no mechanisms in Poland which would balance the burden of this tax for a new investor. In order to balance the extraction tax for certain minerals in terms of the IRR and ETR key indicators, the introduction of several adaptation mechanisms has been proposed. For new investments the most essential mechanism is the preferential settlement of capital expenditures incurred in the pre-production phase of an investment. The others include accelerated amortization, the ability to deduct certain expenses for the exploration phase from the tax base, along with an extended tax loss settlement period, or a mechanism for deducting a certain percentage of investment expenses directly from the tax.
ABSTRACT:
The main goal of this publication is to familiarize western numismatists with the current trends and findings in the research on medieval payment ingots (grivnas) in Eastern Europe. The author presents up-to-date chronological classification of silver payment ingots, shortly describes their basic types and gives the basic list of classic and modern works in this field.
In 2009, in the village of Wysoczany, Sanok district, Podkarpackie voivodeship, a silver coin was accidentally found. This coin is a tetradrachm. It has irregular oval shape and is plano-convex. It is not well preserved, i.e. it has poorly legible depictions on both sides, which significantly impedes its typological classification, and thus its precise dating. The dimensions of the coin are: 27.5 × 28.5 mm and its weight is: 11.83 g (after conservation works). In the case of the described here coin there are no clear analogies and, therefore, there is no certainty to what type it should be attributed. This paper attempts to analyse a few of the existing possibilities. One of the taken into consideration is the south-eastern direction, i.e. Geto-Dacian mintage or Celtic Geto-Dacian one. Some similarities can be found in the following types: Agriş A — Şilindia, Ramna, and also in the category referred to as “the other types” according to the typology by C. Preda. The other possible direction is the central Celtic mintage associated with Boii. However, none of the examples presented in this paper is a close analogy to the coin from Wysoczany. Therefore, its typological attribution as well as its dating remain to be an open question.