Crown ether chiral stationary phases have been successfully used for separating enantiomers of various racemic compounds containing primary amino groups. Although chiral recognition mechanism for crown-ether CSPs is generally understood, on a molecular level, the exact chiral recognition mechanisms for the resolution of short peptides, containing multiple amino moieties capable of binding to...
Substantial amounts of bark of forest trees are a by-product of wood processing, a major proportion of which is used for energy production. Nevertheless, it could also be a valuable source of tannins for use as natural colourants [1]. The barks of many trees are suitable sources of reddish-brown dyes. The most frequently mentioned brown-colouring barks were tannin-rich alder, oak, hemlock and...
Malaria infection in humans is caused by Plasmodium Falciparum parasite. P. Falciparum aspartic proteases (plasmepsins) are responsible for catalytic hemoglobin degradation and thus are being investigated as potential drug targets. Plasmepsins, however, share high structural similarity with human aspartic proteases, emphasizing the need for selective inhibitors. Selectivity of several...
Metal–organic frameworks (MOFs) have been known for decades, and they continuously have gained interest because of their application potential increasing in the various fields – pharmacy, medicine, technology etc [1]. MOFs porous architecture and adjustable properties allow them to be considered as promising drug carriers. Modification of the properties of an existing active pharmaceutical...
University of Latvia, Faculty of Chemistry, Jelgavas iela 1, Riga, Latvia
e-mail: ainasemjonova@gmail.com
Active pharmaceutical ingredients (APIs) can have different physical properties (e.g., solubility [1] and bioavailability) depending on polymorph form. Many APIs have low solubility in water. Crystallization of metastable form can enhance solubility and bioavailability [2]....
Solid solutions (SS) are single multicomponent solid phases for which the constituent component ratio can vary in continuum. Along with the composition, also properties of solid solutions are modulated. The changes in composition are often accompanied by a continuous change in some physical and/or chemical properties (e.g., density, solubility, melting point), and more complex properties such...
The most common method used to control polymorphism is crystallization. An alternative to the most commonly used solvent crystallization is a mechanochemical treatment of a crystalline substance or a mixture of more than one substance. Mechanochemistry is defined as chemical synthesis induced by external mechanical energy, such as grinding two solids using a mortar-and-pestle, ball-mill, or...
Cyclodextrins (CD’s) are cyclic oligosaccharides widely used in pharmaceutical, food and cosmetic industries as excipients and stabilizers. They are produced by enzymatic transformation of starch, obtained from renewable green sources (potato, corn, etc.). This process is unselective and typically leads to a formation of a mixture of CD’s with various numbers of glucose subunits in the cycle...
Nitrocelluose-based substances are dangerous because of their instability; therefore, stabilizers are added, but due constant chemical reactions, they are depleted, that’s why for safety of everyone involved, nitrocellulose-based substance stability must be tested. In the last few years Latvia started to test its own munition on chemical stability, which was limited to chromatographic methods,...
Use of air to water heatpump (AWHP) to reduce CO2 emissions from greenhouse heating were investigated by calculating the running costs of AWHP and natural gas boilers. Real climatic conditions and heating regimes of SIA Rītausma industrial greenhouse production facility in south east of Latvia were used for the calculations. COP of commercially available Hitachi 10kw heating power air-to water...
Sheep breeding in Latvia in the last decade is stabilized and continues to develop. Since sheep breeding includes producing of wool, it is important for fabrication of textiles and thermoinsulators. However, annually tons of wool fibers, that do not fit to requirements to be used in textile industry, remain as residues. Such wool can be used as sorbent [1] or convert in activated carbon [2]...
Graphene – 2D carbon allotrope – is a unique nanomaterial due too its physical properties: semiconductor with zero band gap, high electrical and thermal conductivity, high optical transparency and mechanical strength. Such properties open wide applications of graphene in many fields such as electronics, optoelectronics, thermoelectrics etc. Combination of graphene with other nanomaterials in...
Medical radionuclides as $^{43,44m, 44g,47}$Sc are very promising in “matched theranostic pair” radiopharmaceutical development for cancer treatment. Use of natural titanium as target material for production of $^{43,44m, 44g,47}$Sc radionuclides is favorable in terms of cost and the wide availability of target material, in contrast of using low abundant enriched Ca targets. We report here the...
Lithium orthosilicate (Li4SiO4) and lithium metatitanate (Li2TiO3) for radiation-induced defect studies have been made using numerous methods including sol-gel, melt-spraying, drip-casting and solid-state reaction process in order to evaluate radiation stability of material for application as tritium breeding ceramics in future thermonuclear fusion reactors [1,2]. Solid-state reaction process...
Metallic nanoparticle dispersions for conducting ink preparation
Aleksandrs Novikovs, Boriss Poļakovs
Institute of Solid State Physics, University of Latvia
e-mail: aleksandrs.novikovs@cfi.lu.lv
The aim of this research is to prepare conducting nanoparticle inks, such that it would be possible to print electrical components using a functional ink-jet printer.
Relevance of the topic...
As the use of ion exchange membranes increases, so does the need to improve them. SPEEK membranes are described using their sulfonation degree (DS) that is directly related to other membrane parameters. The degree of sulfonation is defined as the percentage of re-sulfonated SPEEK units. Therefore, it is necessary to find a cheap, easy-to-perform and accurate method for testing DS.
The...
