A three-dimensional microfluidic tumor cell migration assay to screen the effect of anti-migratory drugs and interstitial flow

Most anti-cancer drug screening assays are currently performed in two dimensions, on flat, rigid surfaces. However, there are increasing indications that three-dimensional (3D) platforms provide a more realistic setting to investigate accurate morphology, growth, and sensitivity of tumor cells to chemical factors. Moreover, interstitial flow plays a pivotal role in tumor growth. Here, we present a microfluidic 3D platform to investigate behaviors of tumor cells in flow conditions with anti-migratory compounds. Our results show that interstitial flow and its direction have significant impact on migration and growth of hepatocellular carcinoma cell lines such as HepG2 and HLE. In particular, HepG2/HLE cells tend to migrate against interstitial flow, and their growth increases in interstitial flow conditions regardless of the flow direction. Furthermore, this migratory activity of HepG2 cells is enhanced when they are co-cultured with human umbilical vein endothelial cells. We also found that migration activity of HepG2 cells attenuates under hypoxic conditions. In addition, the effect of Artemisinin, an anti-migratory compound, on HepG2 cells was quantitatively analyzed. The microfluidic 3D platform described here is useful to investigate more accurately the effect of anti-migratory drugs on tumor cells and the critical influence of interstitial flow than 2D culture models.     

Determination of the activation energies of diffusion of organic molecules in poly(ethylene terephthalate)

Poly(ethylene terephthalate) (PET) is a highly inert packaging material that exhibits low interaction with foodstuff and consequently a limited diffusion of migrants. Migration modeling can therefore be used as an alternative to experimental migration tests in order to confirm compliance of PET packaging materials with food laws. The most important factor for predicting migration using mathematical models is the diffusion coefficient of the migrant in PET. However, current models that predict this parameter are typically based on worst‐case scenarios and thereby significantly over‐estimate the degree of migration. The key parameter for developing more realistic migration models is the activation energy of diffusion of potential migrants in PET, but experimental data on this are scarcely available in the scientific literature. The aim of the present study was therefore to develop a fast and precise method for determining diffusion coefficients and activation energies of diffusion of organic compounds in PET. Activation energies of diffusion for 13 organic compounds in PET were determined via their diffusion coefficient temperature dependencies. The molecular weight and activation energy of diffusion for the compounds investigated in this study were correlated, offering a basis for a new approach in predicting diffusion coefficients for use in migration modeling. The proposed method is a suitable tool to establish the datasets needed to refine the current migration model. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Comparison of trilateral cycles and organic Rankine cycles

A comparison of optimized trilateral cycle (TLC) - systems with water as working fluid and optimized organic Rankine cycle (ORC) – systems with pure organic working fluids is presented. The study includes the heat transfer to and from the cycles. The TLC - systems were optimized by the selection of the maximum water temperature, the ORC - systems by the selection of the working fluid and the process parameters. The optimization criterion is the exergy efficiency for power production being the ratio of the net power output to the incoming exergy flow of the heat carrier. Results will be presented for five different cases specified by the inlet temperature of the heat carrier and the inlet temperature of the cooling agent. The inlet temperature pairs are (350 °C, 62 °C), (280 °C, 62 °C), (280 °C, 15 °C), (220 °C, 15 °C) and (150 °C, 15 °C). It is found that the exergy efficiency for power production is larger by 14%–29% for the TLC than for the ORC. On the other hand, the outgoing volume flows from the expander are larger for the TLC than for the ORC by a factor ranging from 2.8 for the first case to 70 for the last case.     

Soft physical vapour deposition coatings—a new coating family for high performance cutting tools

The joint effort of a cutting tool manufacturer and a coating specialist has led to the development of a cutting tool coating based on a soft solid lubricant (patents pending). It is applied by an advanced sputtering technique as a very thin uniform coating with a good adherence to the tools. It has a low coefficient of friction and a low affinity to alloy materials such as aluminium, titanium and precious metals. These factors and others allow machining at high spindle speeds and feed rates with an excellent workpiece surface finish. Values can be maintained which are far superior to even those permitted for cemented carbide tools. In some cases productivity and tool life can be increased by a factor of up to 20.     

Modernisierung des Datenschutzes: Vier Säulen des Datenschutzes

Auf Einladung des Innenausschusses des Deutschen Bundestages fand am 5. M?rz 2007 eine ?ffentliche Anh?rung zum Thema der Modernisierung des Datenschutzes statt. Gegenstand waren Entschlie?ungsantr?ge der Fraktionen der FDP sowie von Bündnis90/Die Grünen zum Datenschutzaudit sowie zum Scoring und zu Auskunftspflichten bei Datenschutzpannen. Stellung genommen hat für das Unabh?ngige Landeszentrum für Datenschutz Schleswig-Holstein Johann Bizer. Das ULD erm?glicht bereits heute die Zertifizierung von Gütesiegeln und Auditverfahren.