Технология синтеза и очистки гликолида

Данная работа посвящена технологии получения и очистки гликолида, как мономера для биоразлагаемых полимеров. Основные потери продукта происходят на стадии получения и очистки мономера. Потери составляют порядка 50-60 %. Целью данной работы является выбор оптимального пути и очистки гликолида. В данной работе проведён и представлен всесторонний литературный обзор по методам получения гликолевой кислоты, гликолида, очистки и полимеризации гликолида. Сравнивались различные катализаторы на стадиях поликонденсации, деполимеризации и полимеризации гликолида. В работе описаны характеристики сырья, описаны способы получения, очистки и полимеризации гликолида. Изложены методики анализа гликолида.This paper is devoted to the technology of production and purification of glycolide as a monomer for biodegradable polymers. The main product losses occur at the stage of monomer production and purification. Losses are about 50-60%. The purpose of this work is to choose the optimal path and purification of glycolide. In this paper, we conducted and presented a comprehensive literature review on methods for producing glycolic acid, glycolide, and purification and polymerization of glycolide. Different catalysts were compared at the stages of glycolide polycondensation, depolymerization, and polymerization. The work describes the characteristics of the raw materials, describes the methods of production, purification, and polymerization of glycolide

INVESTIGATIONS ON THE EXPRESSION AND INFLUENCE OF IONOTROPIC NEUROTRANSMITTER RECEPTORS DURING STEM CELL DEVELOPMENT AND DIFFERENTIATION

PhD Grade Assigned: Meinem Vate

Investigations on the expression and influence of ionotropic neurotransmitter receptors during stem cell development and differentiation

Neurale Stammzellen (NSCs), generiert von embryonalen Stammzellen (ESCs) über das Stadium von neuroepithelialen Zellen (NEPs), weisen alle Merkmale von radialen Gliazellen auf. Sie exprimieren NSC-Marker und sind in der Lage, sowohl in Neurone als auch in Glia zu differenzieren. Im Gegensatz dazu ähneln NEPs der ersten neuralen Stammzellpopulation und differenzieren im Wesentlichen in Neurone. NSCs und NEPs wurden auf die Expression und Funktion von NMDARs, AMPARs und $GABA_{A}Rs$ untersucht. Aufgrund der Expression von iGluRs und neuronalen Marker wurden proliferierende und differenzierende NEPs und NSCs auf ihre Verwandtschaft zu Neuronen untersucht. Die Expression von den iGluR-Untereinheiten wurde mit der Expression von neuronalen Markern wie DCX und NF-H korreliert. Diese Differenzierungsstudien lieferten Erkenntnisse über die Fähigkeit von NEPs und NSCs, funktionell zu neuronalen Netzwerken beizutragen.Neural stem cells (NSCs), generated from genetically modified embryonic stem cells (ESCs) via the stage of neuroepithelial precursors (NEPs), show all characteristics of radial glia cells. They express NSC markers, and they are able to differentiate into both, neurons and glia. By contrast, NEPs resemble the very first neural stem cell population, exhibit Sox1 reactivity, and are primed to differentiate into neurons. The stem cell populations were examined for the expression and function of subunits forming NMDARs, AMPARs, and $GABA_{A}Rs$. Due to the expression of iGluRs and neuronal markers, the proliferating and differentiating neural stem cell populations were classified by their relatedness to neurons. mRNA expression of the iGluR subunits was correlated to the mRNA amount of neuronal markers such as DCX and NF-H. Differentiation studies provided knowledge about the ability of NEPs and NSCs to functionally contribute to neuronal networks

Screening for ecotoxicological effects of antiepileptic drugs in biologically treated waste water originating from an epilepsy ward by Danio rerio embryos

Background Pharmaceuticals, like antiepileptic drugs, are found regularly in surface waters, and consequently, advanced waste water treatment technologies are discussed for substance elimination. Because antiepileptic drugs have shown to transform to more toxic substances, their behavior in these treatment processes and resulting effects on ecotoxicity should be investigated. To validate if waste water from an epilepsy ward of a neurological hospital is appropriate for these investigations, it was treated with a membrane bioreactor (MBR), analyzed for antiepileptic drugs and screened for ecotoxicological effects with Danio rerio embryos. Further, the behavior of antiepileptic drugs in MBR treatment was estimated. Results Treatment of raw hospital waste water by the pilot scale MBR was successful regarding the low dissolved organic carbon concentration in the effluent and allowed ecotoxicological testing with D. rerio. According to the estimated behavior, partial elimination of 10-hydroxy-10,11-dihydrocarbamazepine (10-OH carbamazepine) and rufinamide and some release of lamotrigine, oxcarbazepine and, possibly, primidone occurred. The other investigated substances did not considerably change concentrations due to treatment. The highest concentrated substances found were 10-OH carbamazepine, lamotrigine, and oxcarbazepine. The complex mixture of the treated waste water had no effect on D. rerio morphology and did not change its primary and secondary motor neurons (indicator for developmental neurotoxicity). Oxcarbazepine did not show morphological effects on D. rerio at 8.7 mg L-1. Conclusions Biological treatment was not sufficient to significantly eliminate the load of antiepileptic drugs investigated. No effects on D. rerio embryos were observed. Biologically treated waste water, originating from an epilepsy ward, is appropriate for the investigation of the fate of antiepileptic drugs in advanced treatment processes

Transgenic fluorescent zebrafish Tg(fli1:EGFP)(y1) for the identification of vasotoxicity within the zFET

The fish embryo toxicity test (FET) is currently one of the most advocated animal alternative tests in ecotoxicology. To date, the application of the FET with zebrafish zFET has focused on acute toxicity assessment, where only lethal morphological effects are accounted for. An application of the zFET beyond acute toxicity, however, necessitates the establishment of more refined and quantifiable toxicological endpoints. A valuable tool in this context is the use of gene expression-dependent fluorescent markers that can even be measured in-vivo. We investigated the application of embryos of Tg(fli1:EGFP)^y1 for the identification of vasotoxic substances within the zFET. Tg(fli1:EGFP)^y1 fish express enhanced GFP in the entire vasculature under the control of the fli1 promoter, and thus enable the visualisation of vascular defects in live zebrafish embryos. We assessed the fli1 driven EGFP-expression in the intersegmental blood vessels (ISVs) qualitatively and quantitatively, and found an exposure concentration related increase in vascular damage for chemicals like triclosan, cartap and genistein. The fluorescence endpoint ISV-length allowed an earlier and more sensitive detection of vasotoxins than the bright field assessment method. In combination with the standard bright field morphological effect assessment, an increase in significance and value of the zFET for a mechanism-specific toxicity evaluation was achieved. This study highlights the benefits of using transgenic zebrafish as convenient tools for identifying toxicity in-vivo and to increase sensitivity and specificity of the zFET