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Sol–gel derived hydroxyapatite coatings on metallic implants are important to promote their osseointegration and biocompatibility. However, such coatings generally suffer from drawbacks that limit implant longevity. In this study, the sol gel process to prepare hydroxyapatite was optimized and used to deposit a hydroxyapatite layer on Ti6Al4V. Samples were pretreated by thermal oxidation, sol–gel coating, and anodization to produce titanium dioxide interlayers with various structures. The results of structural and thermal analysis have determined the optimal preparation parameters to produce monophasic and crystalline hydroxyapatite. The introduction of titanium dioxide intermediate layers produced crack-free hydroxyapatite films and promoted the adherence and integrity of the coating, where the adhesive strength was remarkably improved. Furthermore, potentiodynamic polarization tests in simulated body fluid revealed low corrosion rates and high protection property of the hydroxyapatite/titania coated samples, making these structures promising for the coatings of bone replacements. Graphical abstract

The aim of the present research is the electrokinetic determination of the inner surface centercharges of ceramic nanofiltration membranes under varying electrochemical conditions and their influences on the filtration properties especially on salt/ion rejection. Ceramic microporous nanofiltration membranes of TiO2 with pore size of 0.9 nm were characterized. The membrane charge was determined under real filtration conditions at different salt solutions, concentrations and pH-values using flow-through streaming potential measurement. In the case of liquid saturated oxide ceramic membranes a surface charge results from protonated und deprotonated surface groups and specifically adsorbed ions. The charge properties of the amphoteric titania nanofiltration membrane significantly depending on the pH value of the feed. The specific adsorption of multivalent ions modifies additionally the membrane charge and shifts the isoelectric point. Depending on the valence and art of the ions and the pH value/range of the solution the membrane charge is shielded or increased. Using magnitude and sign of the measured streaming potential at different salt solution, concentration and pH-values the salt/ion rejection can be predicted. This could be checked by cross-flow filtration experiments. Single and multivalent ion separation in the nanofiltration range does not only result from a sieving effect/steric exclusion of the pore structure but is strongly influenced by the surface charge characteristics of the pore/channel walls. When the membrane is charged, the ions are retained, and when shielded, the ions pass through the membrane. The investigations show the possibility for adjusting the separation characteristic up to a nearly complete salt rejection by choosing the appropriate pH-value, concentration and the kind of the salt solution. The measurement of the streaming potential during real filtration processes supports in the simplest way the optimization and monitoring of desalination processes with charged nanofiltration membranes.

The electrokinetic phenomena in charged micro- and nanochannels known as streaming current and streaming potential arise when pressure-driven fluid flow transport by advection induces both a current and a potential at the channel ends. This effect can be used as a sensor/transducer principle and also to generate electricity for sensor power supply and therefore represents a mechanism for converting mechanical work into electrical power. Electrokinetic sensors based on streaming potential/current can detect the adsorption of chemicals, drugs or biological markers as well as pressure/flow or pH value. Electrokinetic sensors are passive sensors, simple to build, and can be easily integrated into nano- and microfluidic lab-on-chip systems.

Under reducing conditions fluoride based solid electrolyte sensors with sulphur-sensitive auxiliary electrodes are able to measure the sulphur content in liquid metals and gases at elevated temperatures. In this work CaF 2 doped with YF 3 and SrF 2 doped with LaF 3 were selected as solid electrolyte material, because of their high ionic conductivity. Solid electrolyte tubes were prepared from these materials by slip casting to apply them as electrochemical sensors e.g. in the float glass industry.

Die Abreicherung hoherer Kohlenwasserstoffe aus Erdgas oder Erdolbegleitgasen ist ein unablassiger Schritt vor der Einspeisung in das Endverbrauchernetz. Membrantechnologien konnten dabei als Ersatz fur energieintensive und kostspielige Reinigungsmethoden eingesetzt werden. Vor diesem Hintergrund wurde die entsprechende Eignung zeolithischer MFI-Membranen untersucht und der Einfluss von Membrantragergeometrie, Gaszusammensetzung, Temperatur und Druck auf die Trennung von Methan/n-Butan-Mischungen getestet. The depletion of higher alkanes from methane is a key aspect during the conditioning of natural gases or accompanying gases. Membrane technologies could be used as alternative to energy and cost intensive purifications. Against this background the influence of membrane geometry, composition of the gas mixture as well as temperature and pressure was investigated in separation experiments for methane/n-butane mixtures using MFI membranes.

The separation of higher alkanes from methane is a key aspect for conditioning natural gases and accompanying gases. Against this background, a systematic study on related separation performances of several MFI membranes in dependence on their synthetic origin is presented with this contribution. Basically, MFI slurry was used for the activation of inert Al 2 O 3 supports for heterogeneous crystallization. The resulting MFI seed layer acts both as heterogeneous nucleation side and as flexible distance holder between support and MFI membrane suppressing defect formations during thermal template removal. For the purpose of further optimization, synthesis parameters like temperature, reaction time, pore size of the support and reactant ratios were varied. Characterization of the membranes via permporometry and single gas permeation using methane and n-butane gave first results on the characteristic properties of the membranes obtained. Also, the non isobar performed separations of C 4 /C 1 binary 1:1 mixtures ( p feed = 1 bar, p permeate = 2 bar) are discussed with respect to membrane synthesis. It was found that either selectivity (M10, α = 11.3; J = 128 l m −2 h −1 bar −1 at 75 °C) or permeation flux (M16, α = 3.6; J = 477 l m −2 h −1 bar −1 ) optimized membranes can be generated via different synthetic routes. Both archetypes were tested in a simulated cascade like separation experiment for the isolation of n-butane from C 4 /C 1 = 95:5 mixtures. Under elevated feed pressures ( p feed = 2–11 bar, p permeate = 1 bar) only separation optimized membranes showed a promising applicability due to an increased separation performance also at a lower n-butane content of 6.8%. Increasing feed pressures induced an increase in separation factors from 2.0 to 13.9 at nearly constant permeances of 93–136 l m −2 h −1 bar −1 making customized MFI membranes attractive for technological applications.

Even in the era of multitargeted therapies, cytokines remain at least one of different treatment options in renal cell cancer (RCC), particularly for patients belonging to the good prognostic risk category according to Memorial Sloan Kettering Cancer Center criteria. Granulocyte macrophage-colony stimulating factor plays a central role in the differentiation and activation of antigen presenting cells. This clinical phase 1/2 chemoimmunotherapy trial in metastatic RCC used sequential application of alpha-interferon /5-fluorouracil followed by granulocyte macrophage-colony stimulating factor/interleukin-2. The study was performed before multikinase inhibitors were available for routine use. Twenty patients with metastatic RCC were enrolled into this phase 1/2 protocol. Sequential chemoimmunotherapy was feasible and safe on an outpatient basis. The regimen had only modest antitumor activity with 4 mixed responses and 4 stable diseases being documented after 4 treatment cycles. Enhanced proliferative and stimulatory capacity of peripheral blood mononuclear cells was only observed in patients with mixed responses/stable diseases whereas patients with progressive disease did not show any change. Most interestingly, there was a significant increase of T cells expressing the costimulatory molecules CD80/86 in patients with progressive disease. This finding is reported here for the first time under chemoimmunotherapy of RCC. In conclusion, clinical response rates of this cytokine-based regimen do not justify further clinical evaluation. However, the study suggests that CD80/86+ T cells might have negative regulatory function under cytokine treatment and are possibly useful as a negative predictive marker for clinical response.

In chronic myeloid leukaemia (CML), dendritic cells (DC) and leukaemic cells share a common progeny, leading to constitutive expression of putative tumour antigens, such as bcr/abl, in DC. In this phase-I/II study, autologous DC were used as a vaccine in patients with chronic phase bcr/abl+ CML, who had not achieved an adequate cytogenetic response after treatment with alpha-interferon or imatinib. Ten patients were enrolled, DC were generated from peripheral blood monocytes and vaccination consisted of four subcutaneous injections of increasing numbers of DC (1-50 x 10(6) cells per injection) on days 1, 2, 8 and 21. Vaccination was feasible and safe. Improvement of the cytogenetic/molecular response, as detected by fluorescence in situ hybridization of peripheral blood mononuclear cells (PBMC), was possibly related to vaccination in four of 10 patients. In three of these patients, T cells recognizing leukaemia-associated antigens became detectable. The proliferative capacity of PBMC in response to autologous DC increased after vaccination in all evaluable patients. We conclude that vaccination with autologous, non-irradiated 'leukaemic' DC is feasible, safe and induces anti-leukaemic T-cell responses in some CML patients. DC vaccination might be useful in CML as postremission therapy, i.e. after treatment with tyrosine kinase inhibitors.