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Jaskyne patrili od minulosti k veľmi špecifickým miestam. V niektorých kultúrach boli miestami obetnými, pietnymi, v iných zase tými, kde sa človek dostal na „opačný breh života“. Obyvatelia ich využívali na úkryt, miesto na zanechanie odkazov, či prečkanie zlého počasia, v niektorých aj žili. Vo vojnách sa v našich končinách ukrývali pred nepriateľom aj celé rodiny či dediny, alebo v nich schovávali zbrane. V súčasnosti vo väčšine krajín sú cieľom turistov, ktorí chcú zažiť niečo nové a nepoznané, tmu, vysokú vlhkosť vzduchu aj vidieť fascinujúcu krásu podzemnej výzdoby. No sú aj cieľom jaskyniarov, ktorí túžia jaskyne objavovať, dostať sa do sveta, kde pred nimi ľudská noha nevstúpila, nájsť dôkazy o predchádzajúcom osídlení, alebo robiť výskum, ktorý nás v poznaní posúva stále ďalej a ďalej. V publikácii, ktorú držíte v ruke prinášame viac aj menej tradičné témy o vzniku krasu a jaskýň, vybraných ekologických aspektoch, mapách a ich tvorbe, významných svetových jaskyniach aj o živote človeka v takýchto územiach. Prinášame Vám zároveň prehľad významných krasových lokalít, ktoré stoja určite za to, aby ste sa o nich dozvedeli niečo viac alebo ich osobne navštívili. Táto publikácia je určená pre čitateľov z radov žiakov, študentov, učiteľov aj širokej verejnosti a veríme, že Vás vtiahne do tohto záhadného sveta. URL: https://unibook.upjs.sk/

A novel method for determination of platinum species by application of graphite furnace atomic absorption spectrometry (GFAAS) was developed. The principle of determination is the formation of platinum ion associates (IA) with SCN- and polymethine basic agent 1,3,3-trimethyl-2-[3-(1,3,3-trimethyl-1,3-dihydroindol-2-yliden)-propyl-1,3-dienyl]-3H-indolium chloride (TTDI), which can then be extracted by various organic solvents. Different options for analytical signal intensification (ultrasonic and microwave energy) were examined. The conditions found for ion associate formation and extraction have enabled the proposing of a new Pt(II) and Pt(IV) speciation process. These species can be reliably determined simultaneously at concentration ratios from 1:5 to 5:1. Moreover, the ion associates of platinum with TTDI can be extracted with toluene up to a volume ratio of aqueous and organic phases of Vaq:Vorg = 50:1. This fact for Pt determination using GFAAS means decreasing the limit of detection (LOD) from 7.1 µg L−1 to 0.3 µg L−1. The method was applied for Pt determination in a model and in spiked water samples.

A new, simple, rapid, sensitive, efficient and low-cost spectrophotometric procedure for the determination of gold was developed. The method is based on the reaction of [AuCl 4 ] - with 2-[2-(4-dimethylamino-phenyl)-vinyl]-1,3,3-trimethyl-3H-indolium reagent to form a colored ion associate extractable by various organic solvents. The molar absorptivity of the ion associates is in the range (5.7-9.2) x 10 4 L mol -1 cm -1 depending on the extractant. Butyl acetate was chosen as the extractant. The optimum reaction conditions were established: pH 2-4, concentration of the dye reagent (0.8-1.5) x 10 -4 mol L -1 . The determination of gold is not hindered even by a 1000-fold concentration of Ni and Co; a 500-fold concentration of Pb and Zn; a 100-fold concentration of Bi, Cu, Cd, Pt, Rh and Ru; or a 20-fold concentration of Ag. The established method was applied to the determination of gold in model samples and enriched polymetallic ores.

Based on the reaction of Zn(II), thiocyanate and 2-[2-(5-dimethylamino-thiophen-2-yl)-vinyl]-1,3,3-trimethyl-3H-indolium bromide (DTVTI), a donor-active solvent-assisted liquid-phase microextraction procedure followed by spectrophotometric determination of zinc at 570 nm was developed. The optimum experimental conditions were investigated and found to be as follows: concentration of NH4SCN 0.02 mol L-1, concentration of DTVTI 4 × 10-5 mol L-1. Various extraction solvents were studied alone as well as in mixtures with different improvers, and a mixture of toluene as the extraction solvent and tributylphosphate as the donor-active solvent in a 4:1 v/v ratio was selected. The calibration plot was linear up to 2.62 mg L-1 of zinc with limit of detection 0.09 mg L-1. The developed procedure was applied for zinc determination in dietary supplements. O presente trabalho descreve o uso de microextração em fase líquida com um solvente doador-ativo para a determinação espectrofotométrica de zinco, em 570 nm, usando a reação com tiocianato e com o reagente brometo de 2-[2-(5-dimetilamino-2-tiofenil)-vinil]-1,3,3-trimetil-3H-indolium (DTVTI). As condições experimentais ótimas foram estabelecidas usando NH4SCN 0,02 mol L-1 e DTVTI 4 × 10-5 mol L-1. Estudaram-se ainda vários solventes extratores, separados e em misturas, com diferentes promotores, sendo selecionada a mistura de tolueno como solvente de extração e tributilfosfato como solvente doador-ativo na razão de 4:1 v/v. O sistema mostrou resposta linear até a concentração de 2,62 mg L-1 de zinco com um limite de detecção de 0,09 mg L-1. O método desenvolvido foi aplicado na determinação de zinco em suplementos dietéticos.

The aim of this study was to investigate total mercury (THg) and methylmercury (MeHg) exposure of 75 mother-child pairs in relation to their thyroid hormone status (thyroid-stimulating hormone (TSH), triiodothyronine (T3), free triiodothyronine (fT3), thyroxine (T4), and free thyroxine (fT4)). THg and MeHg in blood samples were measured by atomic absorption spectrometry and gas chromatography-inductively coupled plasma-mass spectrometry, respectively. The median THg and MeHg levels in maternal blood, cord blood, and blood of 6-month-old children were 0.50, 0.53, and 0.32 and 0.22, 0.32, and 0.08 μg/L, respectively. There were significant correlations between paired maternal-cord blood levels for THg and MeHg, with a greater transplacental transport of MeHg compared with THg (mean cord/maternal blood ratio, 1.80 vs. 1.24). The maternal blood THg was found to be a better predictor of TSH levels in children than their current THg exposure. There was a positive correlation between maternal THg and children's TSH. T3 and fT3 levels in children were negatively related to cord blood THg in the majority (Caucasian) subgroup, whereas these associations were positive in the Roma subgroup. Mothers with dental amalgam fillings had significantly lower T4 and fT4 levels. Moreover, fT4 in the mothers of boys negatively correlated with maternal THg levels. MeHg exposure lowered T3 levels in the mothers of girls. Our results suggest that low-level exposure to Hg can affect thyroid hormone status during prenatal and early postnatal exposure depending on the form of Hg, gender, ethnicity, lifestyle, or socioeconomic status (dental amalgam fillings).