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Inverse gas chromatography (IGC) has become a popular technique for the analysis of particulate materials. By injecting certain probe molecules through a column containing the sample as the stationary phase and measuring the retention time of said probe molecules, information on a range of different physicochemical properties, such as surface energy or Hansen-solubility parameters can be obtained. A proper understanding of these physicochemical properties is significant for many industrial processes (e.g. formulation, miscibility of polymer blends, agglomeration), as said processes are often driven by surface properties. Though, IGC analysis has many benefits and is widely used nowadays, the comparability of results that are reported and measured by different operators using different IGC devices has not been investigated yet. Therefore, a round robin test was conducted, where eight organisations analysed two standard materials, silica and lactose, according to a jointly defined protocol using IGC devices that either have a valve-based or a syringe-based dosing system. The results are evaluated based on standard IGC theories and the same mathematical operations are applied to all datasets in order to obtain the specific retention volume and the dispersive surface energy component for the two materials. The resulting values of the calculated parameters vary quite significantly, which is a rather unexpected and a very unpleasant finding for this highly sensitive analytical device. Measurements that are conducted individually by the same operator on the same IGC device report similar results, whereas results obtained by different operators with different types of IGC devices are significantly different. Potential factors for the differences, such as the injected quantity of the probe molecules, are presented and discussed. This round robin test therefore raises some questions on the reproducibility of results obtained via inverse gas chromatography. Furthermore, it demonstrates the need for a standard powder and protocol in order to have a common ground for an objective judgment of results.

Cel pracy Programowana śmierc komorki (apoptozą) jest procesem prowadzącym do śmierci komorki, ktory zachodzi rowniez w guzach nowotworowych. Celem pracy bylo zbadanie zalezności pomiedzy wystepowaniem apoptozy a wybranymi cechami klinicznymi i histopatologicznymi w grupie chorych na raka jamy ustnej. Ponadto porownano odsetki komorek opoptotycznych z ploidią badanych guzow. Material i metody Material do badan stanowily świeze wycinki z guzow nowotworowych jamy ustnej pobranych w trakcie zabiegu operacyjnego. Komorki do badan izolowano enzymatycznie i barwiono metodą Feulgena. Z przygotowanych komorek wykonywano rozmazy, ktore analizowano przy pomocy cytometru obrazowego. Odsetek komorek w poszczegolnych fazach cyklu i apoptozie oceniano przy uzyciu programu CY-FIT. Wyniki Stwierdzono duzą roznorodnośc badanego materialu. Odsetek komorek apoptotycznych nie byl powiązany z wybranymi cechami klinicznymi i histologicznymi. Ponadto nie stwierdzono istotnych roznic statystycznych odsetka komorek apoptotycznych od ploidii guza.