Sensoric Properties of Organic Materials

První část disertační práce je zaměřena na studium změny elektrických parametrů substituovaných ftalocyaninů v důsledku působení vodní páry. Tenké vrstvy byly připravené rotačním nanášením roztoku. V průběhu působení vlhkosti na materiál dochází ke změně elektrických parametrů, jako je např. vodivost a kapacita. Zkoumána byla také sorpce, desorpce a dále změny v elektrických vlastnostech při opakovaném působení vlhkosti na vzorek. Ke studiu byla využita impedanční spektroskopie. Druhá část disertační práce obsahuje optická měření. Jejich změny byly studovány jako odezvy př působení různými plyny (methanolem, ethanolem a 2-propanolem) na vrstvy ftalocyaninu. Proměřované vrstvy byly připravené vakuovým napařováním a sublimací indukovanou obloukovým výbojem. Změna v optické reflektance filmu po působení par plynu byla měřena jako závislost na koncentraci plynu a času působení plynu na vzorek.The first part of the work is aimed to the study of changes of electrical properties of substituted phthalocyanines under the influence of humidity. Thin films were prepared by spin coating technique. During the influenece of humidity electrical conductivity increases. Sorption and desorption and the changes in electrical properties under the repated humidity exposure were investigated as well. Impedance spectroscopy was used for the studies. The second part of this work consists of optical studies and changes of optical parametrsunder the influence of different alcohols (methanol, ethanol, 2-propanol) exposures. The investigated samples were prepared by vacuum evaporation a glow-discharge-induced sublimation. The changes of optical reflectances of the films upon exposure to alcoholvapour-containg atmospheres were studied as a function of alcohol concetration and exposure time.

A 3D Microfluidic Chip for Electrochemical Detection of Hydrolysed Nucleic Bases by a Modified Glassy Carbon Electrode

Modification of carbon materials, especially graphene-based materials, has wide applications in electrochemical detection such as electrochemical lab-on-chip devices. A glassy carbon electrode (GCE) modified with chemically alternated graphene oxide was used as a working electrode (glassy carbon modified by graphene oxide with sulphur containing compounds and Nafion) for detection of nucleobases in hydrolysed samples (HCl pH = 2.9, 100 °C, 1 h, neutralization by NaOH). It was found out that modification, especially with trithiocyanuric acid, increased the sensitivity of detection in comparison with pure GCE. All processes were finally implemented in a microfluidic chip formed with a 3D printer by fused deposition modelling technology. As a material for chip fabrication, acrylonitrile butadiene styrene was chosen because of its mechanical and chemical stability. The chip contained the one chamber for the hydrolysis of the nucleic acid and another for the electrochemical detection by the modified GCE. This chamber was fabricated to allow for replacement of the GCE

Breast cancer-specific mutations in CK1ε inhibit Wnt/β-catenin and activate the Wnt/Rac1/JNK and NFAT pathways to decrease cell adhesion and promote cell migration

Introduction Breast cancer is one of the most common types of cancer in women. One of the genes that were found mutated in breast cancer is casein kinase 1 epsilon (CK1ε). Because CK1ε is a crucial regulator of the Wnt signaling cascades, we determined how these CK1ε mutations interfere with the Wnt pathway and affect the behavior of epithelial breast cancer cell lines. Methods We performed in silico modeling of various mutations and analyzed the kinase activity of the CK1ε mutants both in vitro and in vivo. Furthermore, we used reporter and small GTPase assays to identify how mutation of CK1ε affects different branches of the Wnt signaling pathway. Based on these results, we employed cell adhesion and cell migration assays in MCF7 cells to demonstrate a crucial role for CK1ε in these processes. Results In silico modeling and in vivo data showed that autophosphorylation at Thr 44, a site adjacent to the breast cancer point mutations in the N-terminal lobe of human CK1ε, is involved in positive regulation of the CK1ε activity. Our data further demonstrate that, in mammalian cells, mutated forms of CK1ε failed to affect the intracellular localization and phosphorylation of Dvl2; we were able to demonstrate that CK1ε mutants were unable to enhance Dvl-induced TCF/LEF-mediated transcription, that CK1ε mutants acted as loss-of-function in the Wnt/β-catenin pathway, and that CK1ε mutants activated the noncanonical Wnt/Rac-1 and NFAT pathways, similar to pharmacological inhibitors of CK1. In line with these findings, inhibition of CK1 promoted cell migration as well as decreased cell adhesion and E-cadherin expression in the breast cancer-derived cell line MCF7. Conclusions In summary, these data suggest that the mutations of CK1ε found in breast cancer can suppress Wnt/β-catenin as well as promote the Wnt/Rac-1/JNK and Wnt/NFAT pathways, thus contributing to breast cancer development via effects on cell adhesion and migration. In terms of molecular mechanism, our data indicate that the breast cancer point mutations in the N-terminal lobe of CK1ε, which are correlated with decreased phosphorylation activities of mutated forms of CK1ε both in vitro and in vivo, interfere with positive autophosphorylation at Thr 4

Elektrochemická charakteristika různých syntetizovaných kvantových teček a dopady stárnutí a skladovácí způsob

New type of quantum dots (QDs) are synthesized using various types of passivators, thus the question of their stability and way of storage is still opened not only due to characterization but also due to their wide application (chemistry, chemical biology and biomedicine, gene technology, tumour biology investigation, and fluorescent labelling). In our study, we are interested in the electrochemical changes as a result of aging and storage. We employed a series of aqueous solutions of QDs from various materials with different capping agents (PbS and CuS capped with 3-mercaptopropionic acid, CdS and CdTe capped with mercaptosuccinic acid) and the changes in typical peaks for metals and passivators (acids) were detected by difference pulse voltammetry, after 28 days storage in daylight (25oC) and dark (4oC). Anodic stripping difference pulse voltammetry offers simple and inexpensive approach for monitoring of nanoscaled products behaviour in time, based on evaluation of both - metal and passivator peak.Nový typ kvantových teček (QDS) se syntetizuje za použití různých typů pasivátorů, tedy otázka jejich stability a způsobu skladování je stále otevřena nejen vzhledem k charakterizaci, ale i vzhledem k jejich širokému uplatnění (chemie, chemická biologie a biomedicíny, genové technologie, biologie vyšetřování nádoru, fluorescenční značení). V naší studii jsme se zajímali o elektrochemické změny v důsledku stárnutí a skladování. Využili jsme řadu vodných roztoků QDS z různých materiálů s různými uzávěrovými činidly (PBS a CuS uzavřeny s 3-merkaptopropionová kyselina, CdS, CdTe uzavřeny s kyselinou merkaptojantarové), změny typických vrcholů pro kovy a pasivátory (kyseliny) byly detekovány rozdílem pulzní voltametrie, po 28 dnech skladování v denním světle (25oC) a tmě(4 ° C). Anodické odizolování a rozdíl pulzní voltametrie nabízí jednoduchý a levný přístup k monitorování nanočástic výrobků chování v čase, na základě vyhodnocení obou - kovu a pasivátor vrcholu

The Drosophila homologue of the amyloid precursor protein is a conserved modulator of Wnt PCP signaling

Wnt Planar Cell Polarity (PCP) signaling is a universal regulator of polarity in epithelial cells, but it regulates axon outgrowth in neurons, suggesting the existence of axonal modulators of Wnt-PCP activity. The Amyloid precursor proteins (APPs) are intensely investigated because of their link to Alzheimer's disease (AD). APP's in vivo function in the brain and the mechanisms underlying it remain unclear and controversial. Drosophila possesses a single APP homologue called APP Like, or APPL. APPL is expressed in all neurons throughout development, but has no established function in neuronal development. We therefore investigated the role of Drosophila APPL during brain development. We find that APPL is involved in the development of the Mushroom Body αβ neurons and, in particular, is required cell-autonomously for the β-axons and non-cell autonomously for the α-axons growth. Moreover, we find that APPL is a modulator of the Wnt-PCP pathway required for axonal outgrowth, but not cell polarity. Molecularly, both human APP and fly APPL form complexes with PCP receptors, thus suggesting that APPs are part of the membrane protein complex upstream of PCP signaling. Moreover, we show that APPL regulates PCP pathway activation by modulating the phosphorylation of the Wnt adaptor protein Dishevelled (Dsh) by Abelson kinase (Abl). Taken together our data suggest that APPL is the first example of a modulator of the Wnt-PCP pathway specifically required for axon outgrowth.status: publishe