The Effect of Chemical Compounds on Pigmentation and Depigmentation of Teeth (original) (raw)

Influence of lifetime exposure of sublethal doses of cadmium to selected parameters of carbohydrate metabolism

Potravinarstvo Slovak Journal of Food Sciences, 2012

The aim of the study was to assess the effects of exposure to low doses of cadmium dissolved in drinking water (at a concentration 200 times higher than the maximum permissible dose) on selected parameters of carbohydrate metabolism in 20 Wistar rats. Animals were divided into two groups – control and experimental groups exposed to low doses of cadmium chloride in concentration 20 μM of drinking water. We studied the biochemical parameters, as glucose, hemoglobin, glycated hemoglobin, lactate dehydrogenase and amylase in blood of rats. Glucose, hemoglobin, glycated hemoglobin and amylase levels increased, lactate dehydrogenase was no changed of rats exposed to cadmium. Good indicators of chronic intoxication by cadmium are elevated levels of glucose, hemoglobin and mainly glycated hemoglobin in blood. The evaluation results should be taken into account not only the data at the end of the experiment but for the entire duration of trials (i.e., more time steps), which results largely ...

Magnetoferitín a Jeho Potenciálne Bioaplikácie

2015

Obsah 1. Úvod 2. Magnetoferitín 3. Fyzikálno-chemické vlastnosti magnetoferitínu 4. Potenciálne bioaplikácie magnetoferitínu 5. Záver 1. Úvod Železo je esenciálnym prvkom živých systémov, pre-tože jeho nedostatok spôsobuje bunkovú smrť. Prebytok železa, najmä v podobe Fe 2+ iónov, je pre organizmus to-xický, preto je uskladnený v jadre zásobného proteínu, feritínu, kde sa železo ukladá vo forme hydratovaného železitého komplexného fosfátu [FeO(OH)] 8 [FeO(H 2 PO 4)] s kryštalografickou štruktúrou podobnou minerálu ferihydrit 1-3. Narušenie rovnováhy metabolizmu a uskladňovania železa vo feritíne úzko súvisí s rôznymi ochoreniami, aký-mi sú rakovinové alebo neurodegeneratívne ochorenia 4-7. Patologické zmeny sú sprevádzané prítomnosťou magneti-tu vo feritíne 8-14. Vzniknutá polykryštalická štruktúra feri-tínu môže hrať významnú úlohu v biochemických proce-soch, spojených s rôznymi chorobami. Doteraz nie je dos-tatočne preskúmané, či je vytvorenie biogénneho magneti-tu v mozgovom feri...

Cintoríny ako antropogénne biotopy

2009

Cemeteries are important habitats of plants and animals in cultural landscape, in towns and rural areas (villages). They represent very specific complex anthropogenic habitats formed by anthosoils, stones, walls, trampled areas, grasslands as well as woody plants. High diversity of plant species (cyanobacteria, algae, lichens, mosses, flowering plants), birds and other animals, esp. un-vertebrates, reflects high habitat heterogeneity of the biotope limited by the restricted area. Synanthropic plants, cultivated and spontaneous ones, are dominant and more frequent species in the areas. Species richness depends on cemetery size (area) , habitat diversity (shading by tall trees, original vegetation, geomorphology), age (historical development) as well as human activities in the area (weeding, grass cutting). Cemeteries are considered as sites of naturaliza-tion of introduced organisms and breeding centres of alien species, including invasive plants and animals. But historical cemeterie...

Chain Extension and Foaming of Recycled PET in Extrusion Equipment

Macromolecular Symposia, 2005

In this work industrial scraps of poly(ethylene terephthalate) (PET) were used for the production of foamed sheets. The process was performed by making use of a chemical blowing agent (CBA) in the extrusion process. Due to the low intrinsic viscosity of the recycled PET (IV=0.48dl/g), a chain extender was also used in order to increase the molecular weight of the polymer matrix. Pyromellitic dianhydride (PMDA) and Hydrocerol CT 534 were chosen as chain extender and CBA, respectively. The reactive extrusion and foaming were performed in a two step process, analyzing the feasibility regarding an eventual use in an industrial context. Rheological characterization was carried out on PET samples previously treated with PMDA, as well as the morphological study was performed to define the cellular structure of the foams produced. Moreover, in order to correlate the working conditions in the reactive and the foaming processes with the final morphology of the foams, a mathematical modelling ...

Modelling both the continual erosion and regeneration of discolouration material in drinking water distribution systems

Water Supply, 2014

The erosion of the cohesive layers of particulate matter that causes discolouration in water distribution system mains has previously been modelled using the Prediction of Discolouration in Distribution Systems (PODDS) model. When first proposed, PODDS featured an unvalidated means by which material regeneration on pipe walls could be simulated. Field and laboratory studies of material regeneration have yielded data that suggest that the PODDS formulations incorrectly model these processes. A new model is proposed to overcome this shortcoming. It tracks the relative amount of discolouration material that is bound to the pipe wall over time at each of a number of shear strengths. The model formulations and a mass transport model have been encoded as software, which has been used to verify the model's constructs and undertake sensitivity analyses. The new formulations for regeneration are conceptually consistent with field and laboratory observed data and have potential value in t...