Separation of Enantiomers by Inclusion Gas Chromatography: On the Influence of Water in the Molecular Complexation of Methyl 2-Chloropropanoate Enantiomers and the Modified γ-Cyclodextrin Lipodex-E

A profound influence of water has previously been detected in the complexation of the enantiomers of methyl 2-chloropropanoate (MCP) and the chiral selector octakis(3-O-butanoyl-2,6-di-O-pentyl)-γ-cyclodextrin (Lipodex-E) in NMR and sensor experiments. We therefore investigated the retention behavior of MCP enantiomers on Lipodex-E by gas chromatography (GC) under hydrous conditions. Addition of water to the N2 carrier gas modestly reduced the retention factors k of the enantiomers, notably for the second eluted enantiomer (S)-MCP. This resulted in an overall decrease of enantioselectivity -ΔS,R(ΔG) in the presence of water. The effect was fully reversible. Consequently, for a conditioned column in the absence of residual water, the determined thermodynamic data, i.e. ΔS,R(ΔH) = -12.64 ± 0.08 kJ mol-1 and ΔS,R(ΔS) = -28.18 ± 0.23 J K-1 mol-1, refer to a true 1:1 complexation process devoid of hydrophobic hydration. Chirality 28:124-131, 2015

Intelligent Chiral Sensing Based on Supramolecular and Interfacial Concepts

Of the known intelligently-operating systems, the majority can undoubtedly be classed as being of biological origin. One of the notable differences between biological and artificial systems is the important fact that biological materials consist mostly of chiral molecules. While most biochemical processes routinely discriminate chiral molecules, differentiation between chiral molecules in artificial systems is currently one of the challenging subjects in the field of molecular recognition. Therefore, one of the important challenges for intelligent man-made sensors is to prepare a sensing system that can discriminate chiral molecules. Because intermolecular interactions and detection at surfaces are respectively parts of supramolecular chemistry and interfacial science, chiral sensing based on supramolecular and interfacial concepts is a significant topic. In this review, we briefly summarize recent advances in these fields, including supramolecular hosts for color detection on chiral sensing, indicator-displacement assays, kinetic resolution in supramolecular reactions with analyses by mass spectrometry, use of chiral shape-defined polymers, such as dynamic helical polymers, molecular imprinting, thin films on surfaces of devices such as QCM, functional electrodes, FET, and SPR, the combined technique of magnetic resonance imaging and immunoassay, and chiral detection using scanning tunneling microscopy and cantilever technology. In addition, we will discuss novel concepts in recent research including the use of achiral reagents for chiral sensing with NMR, and mechanical control of chiral sensing. The importance of integration of chiral sensing systems with rapidly developing nanotechnology and nanomaterials is also emphasized

A microplate co-culture assay comprising patient-derived 3D microtumors

After years of extensive research, cancer is still a devastating disease. Even though the knowledge on cancer and its development is growing, a valid close-to-in vivo test system for new drugs is still missing. The aim of this thesis was the successful isolation of 3D patient derived microtumors (PDMs) from various cancer entities and the establishment of a PDM based test system using RCC and malignant melanoma PDMs improving the mentioned shortcomings in cancer drug discovery. PDMs from 11 different tumor entities could be successfully isolated and cultured. The isolated PDMs of RCC and malignant melanoma models are characterized for their viability as well as compared to the patient tumor tissue using Immunohistochemistry. An interesting finding is the presence of cancer stem cells in the PDMs, making it feasible to test agents targeting this subset of cancer cells. By RPPA protein analysis, pathway mutations in the PDMs of different patients were determined and clustered. This information could be used to decide on appropriate PDM models for the testing of novel chemotherapeutic compounds. In future, possible treatment options for patients could be decided on using the RPPA information, ranging from approved SOCs for the specific cancer type to off-label use of approved drugs. Treating single PDMs with different E:T ratios of antigen-specific T cells resulted in disintegration of the PDM and diminished live cell dye fluorescence, reflecting cell death. Based on these findings, a quantitative way to measure cell death was found by using the CellTox Green reagent, which starts to fluoresce green upon binding to free DNA. The established CytoTox assay can be used to test standard of care agents as well as novel chemotherapeutic compounds alone or in combination as well as in an immune cell co-culture. Furthermore, using autologous T cells the effects of checkpoint inhibitors on the ability to target the cancer cells could be investigated. Despite the complex assay condition due to the co-culture set-up, the assay results were reproducible and significant effects were detected with a low standard deviation. During the isolation of the PDMs from patient tissue, TILs can be isolated and cultured for subsequent testing. Furthermore, the isolated TILs can be characterized using flow cytometry analysis to plan the treatment options to be verified using the CellTox™ Green cytotoxicity assay. Moreover, not only cell death could be quantified using the PDMs, but also the PDM infiltration by T cells could be investigated and whether the infiltration can be enhanced by chemotherapeutic compounds or checkpoint inhibitors. Taken together, the presented PDM-based assay is a valid test system for new anti-cancer or immunomodulatory drugs and, in future, if a large enough cohort could be tested, a possible predictive tool for treatment decisions in the clinic.Dissertation ist gesperrt bis zum 17.10.2023 !

Zur Theorie der Arbeitskräftebedarfs-Schätzung für eine wachsende Wirtschaft

Towards a Theory of Planning Manpower Requirements for Economic Growth The paper starts with a critique of the theory and technique of the so-called manpower requirements approach to educational planning and in particular its underlying concept of production and technical progress. In the derivation of manpower needs the approach also uses the traditionally accepted scheme of primary, secondary, and tertiary sectors of production with differing rates of growth of output and productivity. It is argued that a theoretically meaningful and clear classification of production can be obtained through the distinction of the production of goods and services and the production of technical progress (i.e. changes of conditions of production of goods and services). Labor inputs can be classified according to their relation to the production process: primary labor serves immediate production processes of goods and services for final demand; secondary labor serves the production and diffusion of technical progress; tertiary labor serves communication and interaction activities in an increasingly specialized and complex system of production. It is argued that the relative weight of secondary and tertiary labor increases in the process of economic development. Census data of the occupational structure in the Federal Republic of Germany (1950 and 1961) are used to verify this hypothesis in a tentative wa

Ökonomische Aspekte des „Wiederholten Lernens“ (Recurrent Education). Kommentar zum Beitrag von F. Edding

The comment to the above contribution of F. Edding singles out three economic aspects of a system of recurrent education: the question of optimal decisions to invest in education, the adaptation of qualifications in structural changes of the labour market and cost-benefit considerations. Recurrent education is seen as improving the conditions for making educational decisions with respect to criteria of efficiency and equity. For the adaptation of qualifications questions of learning-theory and motivation seem to be unresolved, a special problem refers to the formation of professional identity and competence when educational processes are fragmented and directed by the market. Cost-benefit considerations suggest additional objections against a system of recurrent educatio