Odstraňování rtuti z kyselých roztoků chloridu rtuťnatého sorbenty připravenými katalyzovanou vulkanizací rostlinných olejů

Mercury is a metallic element, dangerous and toxic for the environment. Presently, the incineration of municipal solid waste (MSW) belongs to important sources of Hg emissions. Methods of conversion of metallic mercury and mercury compounds from soluble and toxic forms into water insoluble/non-toxic form (HgS) are sought after. Gaseous HCl and a significant part of HgCl2 vapors present in flue gas from incineration of MSW can be removed there by absorption in hot water. Efficiencies of Hg2+ removal from acidic water solutions by means of sorbents prepared by catalyzed reaction of sulfur with vegetable oils (inverse vulcanization) were studied. These kinds of sorbents were tested and found to be exploitable for selective removal of mercury ions from aqueous solutions, particularly from acidic solutions containing HCl at higher temperatures (50–75 °C). Presence of relatively high concentrations of salts of some other metallic elements (Fe, Zn, Ca) had only very small effects on Hg-sorption. Mercury adsorbed on such sorbents converts relatively quickly into a non-toxic form (HgS). Reactive sulfides and SH‑groups present on the surface of the sorbent particles contribute to a faster sorption of mercury and its conversion to HgS. Leaching of zinc from the catalyst (Zn‑diethyldithiocarbamate) present in the vulcanized sorbents is negligible at neutral conditions and small (about 10 %) at acidic conditions (pH = 1.5).

Metrologické aspekty v analytické chemii: stanovení kovů ve vodách

The monitoring of water quality in the EU is described in detail and regulated by Directives of the European Commission and the Parliament, which underlines the importance of the quality of water (both potable and non-potable). Analysis of trace concentrations of contaminants in water, including metals, still presents challenges to demonstrate the quality and comparability of results. The article provides a detailed overview of the procedures that laboratories can use to assess the reliability of the results obtained by a particular measurement procedure. Emphasis is placed on three basic pillars: metrological traceability, validation and measurement uncertainty. Subsequently continuous evaluation is carried out using internal and external quality management measures. Regional aspects specific for the Czech Republic are also mentioned.

Neurohypofyzární peptidy v lékařství z pražských a švédských laboratoří. Část I: Historie výzkumu a počátky produkce lékových forem

From the fifties to the seventies of the last century, the neurohypophyseal peptides oxytocin and vasopressin constituted one of the main research areas at the Institute of Organic Chemistry and Biochemistry in Prague (IOCB). A significant contribution to this area is associated with the names of František Šorm, director of the said institute, and Josef Rudinger, head of the institute's peptide laboratory. At that time, newly developed research tools enabled to synthesize structural analogues of these hormones in numerous laboratories worldwide and hence to investigate the structure-activity relationships within this peptide group. Contributions of single peptide-chain positions to the respective biological activities were identified which opened a possibility to rationalize a design of peptides with a combination of changes in several positions. Several clinically interesting peptides were synthesized in the late 1960s at the IOCB and employed as therapeutics: [(Gly)3-Cys1,Lys8]-vasopressin (Glypressin Ferring®, Terli­pressin INN), 1-deamino-8-ᴅ-arginine vasopressin (Desmopressin INN, dDAVP), and later the uterotonics carbetocin (INN), widely used in obstetrics to prevent postpartum haemorrhage. Since the industrial production of peptide therapeutics was scarcely possible under the conditions of socialist economy in Czechoslovakia as well as in other countries under the Soviet influence, F. Šorm agreed to use the already established scientific contacts of IOCB with the Swedish pharmaceutical company Ferring AB and to transfer the production licences to Sweden. The license agreements were signed in 1969 and led to a quick spread of dDAVP in the substitution therapy of the central form of diabetes insipidus and, moreover, contributed to a fast upsurge of the Ferring company. Somewhat later, Glypressin was produced as a therapeutic with a prolonged action in cases of cardiovascular collapse. Contacts between Prague peptide chemists and the Ferring company lasted on a rather informal base until the end of the 1980s. After the fall of the totalitarian regime in Czechoslovakia in 1990, Ferring started a joint-venture collaboration with the newly organized Czech company Léčiva st.p. Praha in a newly established group Prague Polypeptide Institute spol. s. r.o. (later Ferring-Léčiva A.S.). A substantial part of the peptide-production capacities was then transferred to new buildings in Prague.

Od PET lahví k dobrotám

The treatment of waste PET bottles has become a pressing global issue over the last few decades, and many scientific teams are currently working on solutions to it. There are many different approaches of how to solve this problem. The present article outlines the possibility to process terephthalic acid, which is the hydrolysis product of polyethylene terephthalate, into vanillin, a compound widely used in the food industry. The work of British scientists who have succeeded in using genetic modification to produce a strain of E. coli RARE_pVanX capable of processing polyethylene terephthalate hydrolysates to the desired vanillin is presented in a broader context.

Dereplikace látek a de novo charakterizace malých molekul z hmotnostních spekter

We describe the molecular dereplication principles and de novo characterization of small molecules obtained from liquid-chromatography mass spectrometry and imaging mass spectrometry data sets. Our methodology aims at supporting chemists and computer programmers to understand the hidden computing algorithms used for metabolomics mass spectrometry data processing. The approaches have been made available in the open-source tool CycloBranch. The presented tutorial extends the interpretation of mass spectra portfolia described in a series of papers published in Chemicke Listy, issues 2/2020 and 3/2020.

Práškové částice pro plicní podání

The deposition of a drug to its required destination is crucial for effective lung treatment. It is important to design a suitable formulation that delivers the active ingredient to the desired site and resists the natural cleansing mechanisms of the airways. Large porous particles used as active substance carriers appear to be the most effective option for lung drug delivery. The present article provides a basic overview of the mechanisms of deposition of dry inhalable powders and methods of their preparation and evaluation. Spray drying together with micronization and crystallization techniques are among the most used methods of preparation of the discussed particles. Besides, these techniques can be combined with other production processes (encapsulation, emulsification, etc.). The evaluation of the properties of particles suitable for pulmonary application is based on specific requirements for their density, porosity, shape, aerodynamic parameters, and deposition in the lungs, which can now be simulated on an accurate model of artificial lungs.

Membránové kontaktory a jejich aplikační potenciál

Nowadays, due to the scarcity of natural resources, there is more pressure on the reuse of materials and the application of circular economy principles. For this purpose, increasingly efficient and energy-saving technologies capable of extracting valuable raw materials from waste streams are needed, thus reducing energy and material dependence on primary resources. One such innovative technology is represented by membrane contactors, which enable mass sharing without the need for phase dispersion within each other, thus achieving lower operational and space requirements, as compared to conventional mass sharing devices (e.g. packed bed, tower column or stirred bed reactors). In addition, membrane contactors are very versatile and can be used not only for the recovery of valuable materials from waste streams in waste management processes (in particular recycling of metals or organics), but also as life-saving devices in biomedical applications (e.g. as extracorporeal blood oxygenation devices).

Štúdium vplyvu chloridov a bromidov na kritickú micelovú koncentráciu a parciálny mólový objem kvartérnej amóniovej soli

The critical micelle concentration (CMC) of the selected surfactant belonging to quaternary ammonium salts with chemical designation N,N-dimethyl-N-(3-((1R,5S)-1,8,8-trimethyl-2,4-dioxo-3-azabicyclo[3.2.1]octane-3yl)propyl)hexadecane-1-amine bromide was determined. Simultaneously, the effect of the addition of various concentrations of NaCl, KCl, NaBr, and KBr salts on the CMC value of the substance was observed and compared with those obtained in an aqueous solution at T = 296,15 K. Based on the results obtained, it was concluded that NaCl and KCl salts decreased the critical micelle concentration, while NaBr and KBr salts did not support micellization and CMC values therefore increased. In the case of solutions of a substance in the salt environment, when compared to the substance's solution in distilled water, a decrease in partial molar volume was observed. From the concentration density dependencies of the substance, an ionization degree of α was determined. Finally, the molar Gibbs energy ∆G° was also calculated and found negative for all salt solutions, while increase with their increasing concentration.