First-principles and experimental studies of fundamental mechanical (elastic moduli, Poisson ratio and hardness) and thermal (expansion coefficient) properties were compared to assess the responses ...in titanium carbide (TiC) based ceramic-metal (cermet) composite systems, and evaluate the potential for predictive modelling of cermet behaviour. The TiC cermets were prepared with 30 vol-% of stoichiometric nickel aluminide (Ni3Al) binder using a liquid phase sintering process, performed at 1500 °C for 60 min. Densities greater than 99% of theoretical were achieved under these conditions. The experimental elastic moduli were determined using a pulse-echo method, while hardness was assessed using the Vickers indentation test. The volumetric thermal expansion of the sample was studied using dilatometry.
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•TiC-30 vol-% Ni3Al cermets have been prepared by vacuum sintering.•Experimental property data is compared with theoretical calculations.•For the individual phases, theoretical and experimental data were in good agreement.•For the cermet system, the ab initio results differ from the experimental findings.
The present work is focused on the cobalt electrodeposition in anodic aluminium oxide and the application of the obtained nanocomposite layer as a monolithic catalyst for complete methane oxidation. ...For the investigation of cobalt nanowires growing in the pores of nanoporous alumina template, cyclic voltametry and galvanostatic method were used. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were applied in order to determine the morphology and the content of the composite material in some stages of its preparation. It was found that the deposition of cobalt from a neutral borate electrolyte is accompanied by release of a small amount of hydrogen, which decreases with the process of nanowires growing.
The emergence of the individual flake cobalt clusters on the alumina template is considered as the most suitable structure of the monolithic catalysts. The final resulting laminar composite structure with outer layer of Co- and Pd-oxides exhibits higher active catalytic properties for methane combustion than the catalysts obtained by conventional procedure of preparation by impregnation.
Glioblastomas (GBM) are highly radioresistant and lethal brain tumors. Ionizing radiation (IR)-induced DNA double-strand breaks (DSBs) are a risk factor for the development of GBM. In this study, we ...systematically examined the contribution of IR-induced DSBs to GBM development using transgenic mouse models harboring brain-targeted deletions of key tumor suppressors frequently lost in GBM, namely Ink4a, Ink4b, Arf and/or PTEN. Using low linear energy transfer (LET) X-rays to generate simple breaks or high LET HZE particles (Fe ions) to generate complex breaks, we found that DSBs induce high-grade gliomas in these mice which, otherwise, do not develop gliomas spontaneously. Loss of Ink4a and Arf was sufficient to trigger IR-induced glioma development but additional loss of Ink4b significantly increased tumor incidence. We analyzed IR-induced tumors for copy number alterations to identify oncogenic changes that were generated and selected for as a consequence of stochastic DSB events. We found Met amplification to be the most significant oncogenic event in these radiation-induced gliomas. Importantly, Met activation resulted in the expression of Sox2, a GBM cancer stem cell marker, and was obligatory for tumor formation. In sum, these results indicate that radiation-induced DSBs cooperate with loss of Ink4 and Arf tumor suppressors to generate high-grade gliomas that are commonly driven by Met amplification and activation.
Cermets based on titanium carbide with a nickel aluminide binder (TiC-Ni3Al) offer potential as substitutes for tungsten carbide (WC) based hardmetals due to their high wear and corrosion resistance ...at ambient and elevated temperatures. In the current work, the effects of post-sinter heat treatments (between 600 and 1340 °C) on atomic ordering of the Ni3Al have been assessed through Vickers indentation, scratch testing and computational modelling. Changes in the atomic structure are evidenced from X-ray diffraction by abrupt increases in the (111) and (200) peak intensities. An increase in Vickers hardness, from 1400 to 1530 HV, is observed as a result of heat treatment at 1200 °C. Furthermore, the scratch hardness value was improved from 11.89 to 18.12 GPa, with the main wear mechanisms being identified as TiC grain pull out and brittle fracture. Ordering transitions were subsequently related to the structural changes predicted through ab-initio modelling approaches.
•Ordering heat-treatments have been applied to TiC-Ni3Al cermets up to 1340 °C.•TiC grain size increases slightly when ordering between 1000 and 1340 °C (for 2 h).•Hardness increased from 1400 to 1530 HV when heat treating at 1200 °C.•The scratch hardness value was also improved from 11.9 to 18.1 GPa at 1200 °C.•The main wear mechanisms were identified as TiC grain pull out and brittle fracture.
TGF-β can signal by means of Smad transcription factors, which are quintessential tumor suppressors that inhibit cell proliferation, and by means of Smad-independent mechanisms, which have been ...implicated in tumor progression. Although Smad mutations disable this tumor-suppressive pathway in certain cancers, breast cancer cells frequently evade the cytostatic action of TGF-β while retaining Smad function. Through immunohistochemical analysis of human breast cancer bone metastases and functional imaging of the Smad pathway in a mouse xenograft model, we provide evidence for active Smad signaling in human and mouse bone-metastatic lesions. Genetic depletion experiments further demonstrate that Smad4 contributes to the formation of osteolytic bone metastases and is essential for the induction of IL-11, a gene implicated in bone metastasis in this mouse model system. Activator protein-1 is a key participant in Smad-dependent transcriptional activation of IL-11 and its overexpression in bone-metastatic cells. Our findings provide functional evidence for a switch of the Smad pathway, from tumor-suppressor to prometastatic, in the development of breast cancer bone metastasis.
Isoflavone levels and isoflavone chemical composition in 11 cultivars of soybean, including 4 Indian and 7 genotypes of soybean grown in Bulgaria, were analyzed as determined by C18 reversed phase ...high-performance liquid chromatography coupled with a photodiode array detector. Antioxidant activity of soybean extracts was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and total phenolic compounds (TPC) were determined by using Folin−Ciocalteu reagent. The range of total isoflavones (TI) was 558.2−1048.6 µg g−1 of soy in Indian cultivars, and it was 627.9−1716.9 µg g−1 of soy in the case of Bulgarian cultivars. The highest and lowest total isoflavone contents were observed for Maus-2 (1048.6 µg g−1 of soy) and Hardee (558.2 µg g−1 of soy), respectively, for the Indian cultivars, and they were observed for Boryara (1716.9 µg g−1 of soy) and Line 5 (627.9 µg g−1 of soy) for the Bulgarian genotypes. DPPH radical scavenging activity did not differ significantly among the cultivars and did not correlate with TI, whereas TPC correlated well with TI and weakly with DPPH. Malonylglucoside of all the aglycones, total genistein (TGin), and total daidzein (TDin) showed strong correlation with total isoflavones, whereas acetylglucoside and aglycone levels did not significantly correlate with total isoflavone. Profiling of soybean isoflavone is helpful in understanding the regulation of isoflavone biosynthesis for greater improved resistance of crops to disease and greater health benefits for humans. This comparative study of soybean cultivars grown in India and Bulgaria throws light on their composition and nutraceutical value.
Psoriasis is a chronic inflammatory skin condition characterized by abnormal keratinocyte proliferation and differentiation that is accompanied with dysregulated immune response and abnormal ...vascularization. Devil’s claw (Harpagophytum procumbens (Burch.) DC. ex Meisn.) tubers extract has been used both systemically and topically for treatment of chronic inflammatory diseases such as arthritis, osteoporosis, inflammatory bowel disease, among others. However, its potential mechanisms of action against psoriasis remains poorly investigated. The human keratinocyte HaCaT cell line is a well-accepted in vitro model system for inflammatory skin disorders such as psoriasis. The present study involved an exploration of the effect of biotechnologically produced H. procumbens (HP) cell suspension extract and pure phenylethanoid glycosides verbascoside (VER) and leucosceptoside A (LEU) in interferon (IFN)-γ/interleukin (IL)-17A/IL-22-stimulated HaCaT cells as a model of psoriasis-like inflammation. Changes in key inflammatory signaling pathways related to psoriasis development were detected by reverse transcription polymerase chain reaction and western blotting. Treatment with LEU, but not VER and HP extract improved psoriasis-related inflammation via suppression of the PI3K/AKT signaling in IFN-γ/IL-17A/IL-22-stimulated HaCaT cells. Our results suggest that LEU may exhibit therapeutic potential against psoriasis by regulating keratinocyte differentiation through inhibition of the PI3K/AKT pathway.
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•Synthesis of CoMn/SBA-15 catalysts for CO and VOCs oxidation.•Mesoporous structure of SBA-15 prevents the oxides agglomeration.•Oxide nanowires formation in the channels of Mn-SBA-15 ...and CoMn/SBA-15 catalysts.•The most active bi-component catalyst is that one with Co:Mn molar ratio of 1:0.5.
Mono- and bi-component cobalt and manganese samples were prepared by “two-solvent’’ technique using SBA-15 as a support. The obtained materials were characterized by SAXS (Small angle X-Ray scattering), N2 adsorption-desorption, X-ray diffraction, TEM (Transmission Electron Microscopy), X-ray photoelectron spectroscopy (XPS), TPR (Temperature-programmed reduction) and O2-TPD (Oxygen Temperature-programmed desorption). The catalytic properties were tested in the complete oxidation of propane, n-hexane, and carbon monoxide.
The modification of the SBA-15 materials with Co, Mn or simultaneously with both cobalt and manganese does not change significantly the mesoporous structure, however its pores are partially blocked by the oxides, resulting in the decrease in the specific surface area and in the pore volume. In the case of mono component Co-SBA-15, the clusters of Co3O4 are on the surface and they are partially located inside the pore system of SBA-15 while for Mn-SBA-15 sample, the oxide phases preferentially fill up the channels of SBA-15 forming nanowires. The mixed oxide nanowires are formed in the channels of CoMn-SBA-15 material along with small nanoparticles, aggregated outside of the channels.
The mesoporous structure and morphology of SBA-15, type of oxide phases and the size of the oxide particles remain almost unchanged after tests in reaction of complete n-hexane oxidation and this is valid for all studied samples. The observed resistance towards agglomeration can be attributed to the mesoporous structure. On the other hand, after reaction the surface concentration of different cobalt and manganese species undergoes significant changes, except for the sample with equimolar Co:Mn ratio.
The most active catalyst among bi-component Co-Mn samples in all studied reactions is the catalyst where the Co:Mn molar ratio is 1:0.5, which can be explained by the formation of finely divided oxides, thus ensuring highest reducibility and oxygen mobility.
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