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The potential of the wet powder spraying (WPS) process for the depositon of thin dense films for solid oxide fuel cell electrolytes is demonstrated. In contrast to many other production methods the process allows high deposition rates. Economical aspects such as good up‐scaling, low investment costs for the equipment and short sintering times for the layers make the WPS process an interesting alternative to other deposition techniques.

Das Standard-Wärmedämmschichtmaterial Ytttriumoxid-stabilisiertes Zirkonoxid (YSZ) ist für den Langzeiteinsatz auf eine maximale Temperatur von etwa 1200°C beschränkt. Dementsprechend kann ein weiterer Anstieg der Gaseinlaßtemperatur und damit der Effizienz von Gasturbinen kaum mit YSZ-Beschichtungen erreicht werden. In einem Auswahlprozeß wurden besonders Perowskit- (ABO3, A = Sr,Ba, B = Zr) und Pyrochlor(A2B2O7, z.B. A = La oder andere Seiten-Erd-Elemente, B = z.B. Zr)-Materialien als mögliche Kandidaten für Wärmdämmschichten identifiziert. Grundlegende physikalische Eigenschaften (z.B. Wärmeausdehnungskoeffizient, Temperaturleitfähigkeit und Wärmeleitfähigkeit) von einigen Kandidaten wurden an gesinterten, dichten Proben bestimmt. Die Möglichkeit zur Optimierung der Eigenschaften durch spezifische Zusammensetzungen wird diskutiert. Von den vielversprechenden Materialien wurden Pulver, die für das Plasmaspritzen geeignet sind, über das Sprühtrocknen hergestellt. Neue WDS-Systeme, die aus über das atmosphärische Plasmaspritzen abgeschiedenen neuen Materialien und mit Vakuumplasma-gespritzten Haftvermittlerschichten bestanden, wurden in einem Gasbrennerteststand untersucht. Besonders La2Zr2O7-Beschichtungen zeigten vielversprechende Ergebnisse. Eine weitere Verbesserung konnte durch den Einsatz von lagigen oder gradierten Schichten mit einer YSZ-Schicht an der Haftvermittlerschicht und dem neuen Material als oberste Schicht erzielt werden. Erste Ergebnisse von thermischen Zykliertests bei 1250 und 1350°C Oberflächentemperatur werden präsentiert.

A new concept of thermal barrier coating (TBC) system is presented, based on a metal-glass composite (MGC). Coatings of metal-glass composite can be deposited by vacuum plasma spraying and slip casting with a subsequent sinter step. In this TBC system the thermal expansion coefficient depends on the metal-glass ratio. It is chosen in such a way that the thermal expansion coefficient of the composite is close to the one of the substrate. This leads to reduced thermal stresses and hence improved thermal cycling life times. Because of the low thermal mismatch, coatings of more than 600 μm thickness can be realized. Another advantage of the gas tight composite coatings is their ability to protect the bondcoat from severe oxidation. Correspondingly, long life times have been found for these TBCs in oxidation tests. Also good results were found during thermal cycling tests. Furthermore some aspects of the microstructure evolution of the composite during heat treatment are described.

We present experimentally determined scattering matrix elements of birefringent rutile particles in water as a function of the scattering angle for a wavelength of 633 nm (in air). These elements are compared with the results of T-matrix calculations for prolate spheroids. For the diagonal matrix elements the results of the T-matrix calculations are in good agreement with those of the measurements. A good fit for the whole matrix, including the off-diagonal elements, is obtained when we compensate for the birefringence of the rutile particles by performing the computations for spheroids with a slightly larger length/width ratio than measured.

The manufacture of fine-grained SiC ceramics by using nanophase SiC powders with particle sizes of about 20 nm is described. Conventional sintering of these powders led to extreme grain growth and hence the nanophase microstructure was destroyed. Pressure-assisted sintering was applied to reduce the sintering temperature and also grain growth. Hot isostatic pressing (HIPing) of samples with about 1 wt carbon and 1 wt boron addition at temperatures below 1700°C and with pressures up to 350 MPa resulted in densities of more than 95 of the theoretical density (TD) and grain sizes of 150 nm. A further reduction of grain size became possible by an optimized high-temperature heat treatment of the samples prior to HIP. This procedure removed at least partially the oxygen layer on the surface of the nanophase SiC particles. Samples with densities of more than 97 TD and grain sizes below 80 nm were produced. Grain sizes were measured with scanning and transmission electron microscopes; both methods gave similar values. Grain sizes determined from the peak broadening of X-ray diffraction peaks showed in some cases lower values. This was attributed to the relatively high amount of twinning boundaries and stacking faults produced during crystal growth. The influence of the grain size on different mechanical and thermal properties was investigated. Vickers hardness and indentation fracture toughness were measured for samples with different densities and grain sizes. The results revealed that besides grain size features like density andor oxygen content can strongly influence hardness and fracture toughness. Similar results have been found for the wear resistance of fine-grained materials. Results of pin-on-disk type experiments showed the importance of a high density of the samples for high wear resistance. Thermal diffusivity measurements were performed for samples with different grain sizes up to 1400°C. A large decrease with decreasing grain size was found at room temperature. At higher temperatures the difference in the thermal diffusivity of fine- and large-grained materials was reduced.

The hyperfine structure in the odd-parity 6snh (9 ≤ n ≤ 40) Rydberg series of barium has been investigated, using a single cw ring dye laser and a beam of neutral atoms in the metastable 5d^2 1G_4 state. Owing to small fine-structure splitting, this hyperfine structure is dominated by the Fermi contact interaction of the 6s electron already at n = 12. The hyperfine-structure analysis results in a determination of the complete fine structure of the 6snh series as well as in values for the singlet–triplet mixing in the 6snh J =5 states. The 6snh series turn out to be perturbed by levels of the 5d4f configuration; J = 4 and J = 5 levels of this configuration have been observed. The Rydberg series perturbations are analyzed, using multichannel quantum-defect theory in the shifted R-matrix formalism. Far from the 5d4f perturbers, the 6snh configuration is almost purely jj coupled.

The hyperfine structure in the odd-parity 6snh (9 ≤ n ≤S 40) Rydberg series of barium has been investigated, using a single cw ring dye laser and a beam of neutral atoms in the metastable 5d^21G_4 state. Owing to small fine-structure splitting, this hyperfine structure is dominated by the Fermi contact interaction of the 6s electron already at n = 12. The hyperfine-structure analysis results in a determination of the complete fine structure of the 6snh series as well as in values for the singlet-triplet mixing in the 6snh J =5 states. The 6snh series turn out to be perturbed by levels of the 5d4f configuration; J = 4 and J = 5 levels of this configuration have been observed. The Rydberg series perturbations are analyzed, using multichannel quantum-defect theory in the shifted R-matrix formalism. Far from the 5d4ƒ perturbers, the 6snh configuration is almost purely jj coupled.

Wet powder pouring (WPP) was developed as an alternative near net shape process to metal injection moulding (MIM). The amount of binder, which is necessary to obtain a sufficient green strength, is relatively low (2–5 vol.-%) compared to the amount used in the MIM process (about 30 vol.-%). This is advantageous with respect to short debinding times and low residual carbon and oxygen contaminations. A further reduction of the binder content or the application of the WPP process to new materials would be promoted by an understanding of the dependence of green strength on particle characteristics and binder content. In the present investigation the green strengths of stainless steel WPP parts were determined for different particle size distributions and different binder contents (2–8 vol.-%). The green strength was in the range 3 to 7 MN m−2and the fracture mode was always brittle. A simple fracture mechanical model was developed, which was able to explain the observed relations between binder content, particle size, and green strength. PM/0658

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Several types of silicon based nanocomposite ceramics have been produced by hot isostatic pressing (HIP) mixtures of ultrafine SiC, CSiC and SiSiC powders (particle size below 50 nm) with conventional carbon, boron carbide or silicon carbide powders. Compared to pressureless sintering grain growth was substantially reduced by this technique. Samples have been characterized with respect to microstructure. Thermal conductivity measurements at room temperature indicate a reduction of thermal conductivity compared to conventional materials. High heat flux experiments in the electron beam test facility JUDITH (Juelich divertor test equipment in hot cells) with energy densities up to 11 MJ/m2have been performed. Although the thermal conductivity is relatively low the materials prepared from SiSiC/C-mixtures show lower erosion rates compared to conventional composites. The negative effect of low thermal conductivity on thermal shock resistance seems to be overcompensated by the microstructural improvements in the nanocomposite materials. A model, which calculates the erosion rates and takes account of microstructural features like chemical composition and grain size, is presented.

Ceramic composites as candidate materials for plasma facing components were developed by hot isostatic pressing of SiC, B4C, TiC and C powders. Energy densities similar to those expected during disruptions in ITER were applied to these composites by using the electron beam facility JUDITH in the KFA. The experimental energy densities range from 2 to 80 MJ/m2and pulse durations from 5 to 25 ms. Erosion losses as a function of energy density and material composition have been evaluated. Surface temperature response have been measured by using a special pyrometer. An analytical model based on the balance of heat fluxes has been developed to estimate the erosion losses. Correlation of experimental and simulation results for material erosion gave hints to further optimisations.

Three different ceramic matrix composites (CMCs) were produced using Cr2AlC as a matrix, and carbon, SiC and Al2O3short fibers as a secondary phase. Cr2AlC powders were synthesized by solid-state reaction, followed by mixing with the fibers, and full densification using a field-assisted sintering technique. Of the three different fiber types, Carbon fibers reacted strongly with Cr2AlC, while the reaction with SiC fibers was more limited and alumina fibers didn’t show any reaction. Oxidation tests of the monolithic Cr2AlC and the composites were performed by thermogravimetric analysis. An alumina layer formed at 1000 °C on every sample, well attached and worked as a good oxidation barrier. Under realistic conditions using a burner rig for cyclic oxidation at 1200 °C for 500 cycles, the oxidation resistance of the alumina fiber CMC is good, as no defects or degradation are visible and the alumina layer is well attached.

Despite numerous studies and decades of industrial application, there is still a lack of understanding about the formation and the impact of aluminum titanate (Al2TiO5) in Al2O3-TiO2 thermal spray coatings. Especially the influence of the feedstock powder characteristics on the phase composition has only crudely been investigated so far. Therefore, in this work we have characterized commercial fused and crushed Al2O3-TiO2 feedstock powders: three of them containing 13 wt.% TiO2 and three containing 40 wt.% TiO2. The effect of the varying phase compositions of the powders and their relevance on the deposition efficiency, the phase compositions, the porosity, and the hardness of the respective APS coatings is described in detail. While detrimental to the mechanical properties of 40 wt.% TiO2 coatings, we have found an enhancement of the hardness for 13 wt.% TiO2 coatings with a high Al2TiO5/Al6Ti2O13 content in the feedstock powder. Furthermore, it was found that Al2TiO5 may reform during APS when sprayed from an Al2TiO5-free powder.

This work focuses on recent developments of plasma spray processes with respect to specific demands in energy technology. High Velocity Atmospheric Plasma Spraying (HV-APS) is a novel variant of plasma spraying devoted to materials which are prone to oxidation or decomposition. It is shown how this process can be used for metallic bondcoats in thermal barrier coating systems. Furthermore, Suspension Plasma Spraying (SPS) is a new method to process submicron-sized feedstock powders which are not sufficiently flowable to feed them in dry state. SPS is presently promoted by the development of novel torch concepts with axial feedstock injection. An example for a columnar structured double layer thermal barrier coating is given. Finally, Plasma Spray-Physical Vapor Deposition (PS-PVD) is a novel technology operating in controlled atmosphere at low pressure and high plasma power. At such condition, vaporization even of high-melting oxide ceramics is possible enabling the formation of columnar structured, strain tolerant coatings with low thermal conductivity. Applying different conditions, the deposition is still dominated by liquid splats. Such process is termed Low Pressure Plasma Spraying-Thin Film (LPPS-TF). Two examples of applications are gas-tight and highly ionic and electronic conductive electrolyte and membrane layers which were deposited on porous metallic substrates.

In this work, a mechanically redox-stable SOFC with a 1 µm thin-film sol-gel electrolyte is presented. With this electrolyte a power output larger than 1.25 W/cm2at 0.7 V and an operating temperature of 600 °C could be demonstrated. Half cells were re-oxidized in excess air, in order to test the redox stability of these SOFCs. No cracks were found in the sol-gel electrolyte after re-oxidation for 4 hours at 600 °C and 30 minutes at 800 °C, respectively. Due to the fact, that the energy release rate is proportional to the thickness of the thin-film, a thinner film is more stable against cracking than a thicker film at constant tensile stresses. The SOFC with the thin-film sol-gel electrolyte can be considered as stable against re-oxidation, because the long re-oxidation time of 4 hours at an operating temperature of 600 °C is unlikely to happen under real conditions.

No relevant conflicts of interest to declare.

No relevant conflicts of interest to declare.

Duehrsen: Alexion: Honoraria.

No relevant conflicts of interest to declare.

No relevant conflicts of interest to declare.

Abstract 223

No relevant conflicts of interest to declare.

Abstract 350

Abstract 3217

Abstract 2358

No relevant conflicts of interest to declare.

No relevant conflicts of interest to declare.

Abstract 997

Inflammatory responses are complex and comprise multiple mediators including cytokines such as TNF-alpha (TNF-α) and IL-1beta. These cytokines are synthesized and secreted in response to signaling by plasma membrane receptors of the Toll-like receptor (TLR) family. A central downstream element of TLR-dependent signaling is the transcription factor NF-kappaB (NF-κB), which plays a pivotal role in controlling the proper sequence of events during an inflammatory response. In unstimulated cells, NF-κB is bound to inhibitory IkappaB (IκB) proteins and remains sequestered in the cytoplasm. Stimulation of TLRs triggers a signaling cascade that leads to phosphorylation and proteasomal degradation of IκB, resulting in the translocation of NF-κB to the nucleus, where it acts as a transcriptional activator of target genes. To keep the innate immune system under control, the TLR signaling cascade is under a tight control of many positive and negative regulators. We have previously shown that the transcription factor Growth Factor Independence 1 (Gfi1) represents a novel factor limiting the inflammatory immune response including TNF-α. Gfi1-deficient (Gfi1−/−) mice show a very strong systemic response to the TLR4 ligand and endotoxin LPS and die rapidly within 36 h with symptoms of septic shock. Here, we investigated the molecular mechanism of this exaggerated TNF-α production in the absence of Gfi1. It is known that endotoxin stimulation results in the activation of the transcription factor NF-κB through TLR4, leading to TNF-α production. This activation also resulted in rapid and de novo expression of Gfi1 in the nucleus in a time- and dose-dependent manner. The expression of Gfi1 was not due to feedback regulation from secreted TNF, since TNF-deficient macrophages were also able to upregulate Gfi1 mRNA following LPS stimulation. As expected, LPS stimulation of Gfi1−/− macrophages resulted in significantly higher levels of TNF-α mRNA, and secreted TNF-α cytokine. Strikingly and in contrast to most known negative regulators of TLRs, Gfi1 did not affect the activity or the expression levels of the cytoplasmic components of TLR signaling pathway. Additionally, NF-κB phosphorylation and nuclear translocation post- LPS treatment were intact in both Gfi1−/− and Gfi1+/+ macrophages. Immunoprecipitation analysis from cells endogenously expressing Gfi1 and NF-κB or over-expressing these two proteins post transfection, clearly revealed a direct interaction between Gfi1 and the p65 subunit of NF-κB. Immunofluorescence staining of macrophages post-LPS treatment confirmed direct interaction of these two proteins in the nucleus at the endogenous level. Gfi1 represses transcription by binding to DNA recognition sequences in target gene promoters. Thus, aiming to investigate the effect of Gfi1 expression on NF-κB nuclear signaling, we found that LPS treatment enhances NF-κB DNA binding activity in Gfi1−/− macrophages as compared to Gfi1+/+ cells. Furthermore, over expression of Gfi1 protein resulted in negative regulation of NF-κB mediated gene activation in a dose-dependent manner. Chromatin immune precipitation with anti-p65 antibodies from LPS stimulated Gfi1+/+ and Gfi1−/− macrophages revealed enhanced NF-κB promoter occupancy at the TNF gene in Gfi1−/− macrophages as compared to Gfi1+/+ cells. In conclusion, our findings reveal a novel function for Gfi1 in the innate immune response by directly antagonizing NF-κB function. This molecular perceptive of TNF-α regulation during inflammation may provide an attractive strategy for therapeutic intervention in chronic inflammatory diseases and certain cancers.

Chronic myeloid leukemia (CML) is one of the most frequent leukemic diseases and invariably associated with a reciprocal t(9;22) translocation which creates a juxtaposition of the BCR and ABL genes to form the p230-, p190- or p210BCR-ABL constitutively active tyrosine kinases. This constitutive tyrosine kinase activity is the cause of CML and other leukemic diseases. CML is very efficiently treated with small molecule tyrosine kinase inhibitors, but CML is a stem cell initiated disease and surprisingly the leukemic stem cells cannot be eradicated by tyrosine kinase inhibitor treatment, resulting in a high risk of the development of therapy resistance. To design more successful therapies, it is primordial to understand the molecular mechanisms underlying this disease. Here we show that growth factor independent 1b (Gfi1b), also translocated in CML, is strongly induced in peripheral blood mononuclear cells (PBMCs) in patients with chronic- or acute myeloid leukemia (AML) as well as in patients suffering from myeloprolifarative syndrome (MPS) or B-lymphoblastic leukemia (B-ALL). Gfi1b is a transcriptional repressor essential for erythroid- and megacaryocytic cells, but also expressed in hematopoietic stem cells, early myeloid precursors and mature myeloid cells in peripheral blood. Interestingly, the expression of Gfi1b is further induced by long term treatment with tyrosine kinase inhibitors like Glivec, although the patients are phenotypically in remission. Additionally we describe a new splice variant of Gfi1b which is overrepresented in CML, AML and B-ALL, but not in MPS. Using a mouse model system we demonstrate, that Gfi1b strongly accelerates p210BCR-ABL induced leukemogenesis. We further show that Gfi1b inhibits the activity of PU.1, a key molecule in hematopoiesis and repressor of leukemogenesis. Our findings bear considerable significance with regard to the role of Gfi1b as an oncogene in human leukemia and to its possible value as a new target for leukemia therapy.

Chronic myeloid leukemia (CML) is one of the most frequent leukemic diseases and invariably associated with a reciprocal t(9;22) translocation which creates a juxtaposition of the BCR and ABL genes to form the p230-, p190- or p210BCR-ABLconstitutively active tyrosine kinases. This constitutive tyrosine kinase activity is the cause of CML and other leukemic diseases. CML is very efficiently treated with small molecule tyrosine kinase inhibitors, but CML is a stem cell initiated disease and surprisingly the leukemic stem cells cannot be eradicated by tyrosine kinase inhibitor treatment, resulting in a high risk of the development of therapy resistance. To design more successful therapies, it is primordial to understand the molecular mechanisms underlying this disease. Here we show that growth factor independent 1b (Gfi1b), also translocated in CML, is strongly induced in peripheral blood mononuclear cells (PBMCs) in patients with chronic- or acute myeloid leukemia (AML) as well as in patients suffering from myeloprolifarative syndrome (MPS) or B-lymphoblastic leukemia (B-ALL). Gfi1b is a transcriptional repressor essential for erythroid- and megacaryocytic cells, but also expressed in hematopoietic stem cells, early myeloid precursors and mature myeloid cells in peripheral blood. Interestingly, the expression of Gfi1b is further induced by long term treatment with tyrosine kinase inhibitors like Glivec, although the patients are phenotypically in remission. Additionally we describe a new splice variant of Gfi1b which is overrepresented in CML, AML and B-ALL, but not in MPS. Using a mouse model system we demonstrate, that Gfi1b strongly accelerates p210BCR-ABLinduced leukemogenesis. We further show that Gfi1b inhibits the activity of PU.1, a key molecule in hematopoiesis and repressor of leukemogenesis. Our findings bear considerable significance with regard to the role of Gfi1b as an oncogene in human leukemia and to its possible value as a new target for leukemia therapy.

For Abstract see ChemInform Abstract in Full Text.

This volume is a fascinating, erudite, gripping, and well-researched work on a subject that many of us would expect to find dry, dull, and for academics only. John Man has succeeded, however, in taking and transforming the topic into a highly readable and very accessible book that reads like a whodunit from beginning to end. He traces the origins of the alphabet, from 4,000 years ago to modern times, taking us on captivating and exotic excursions along the way: how the Exodus might have come about; who the Phoenicians were and how they got their name; how Cyrillic came into being; how Times Roman has come to be one of the most popular and recognizable typefaces today.

This volume is a fascinating, erudite, gripping, and well-researched work on a subject that many of us would expect to find dry, dull, and for academics only. John Man has succeeded, however, in taking and transforming the topic into a highly readable and very accessible book that reads like a whodunit from beginning to end. He traces the origins of the alphabet, from 4,000 years ago to modern times, taking us on captivating and exotic excursions along the way: how the Exodus might have come about; who the Phoenicians were and how they got their name; how Cyrillic came into being; how Times Roman has come to be one of the most popular and recognizable typefaces today.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Irradiation of isopropanol in the presence of benzophenone according to method A) generates hemipinacol radicals.

Photochemical reaction of the chiral esters (I) with the dihydrooxazole (II) occurs selectively to give the oxetanes (III) and (IV) with endo phenyl groups (both the main products (III) can be isolated with 53% yield).