A novel canine kidney cell line model for the evaluation of neoplastic development: karyotype evolution associated with spontaneous immortalization and tumorigenicity

The molecular mechanisms underlying spontaneous neoplastic transformation in cultured mammalian cells remain poorly understood, confounding recognition of parallels with the biology of naturally occurring cancer. The broad use of tumorigenic canine cell lines as research tools, coupled with the accumulation of cytogenomic data from naturally occurring canine cancers, makes the domestic dog an ideal system in which to investigate these relationships. We developed a canine kidney cell line, CKB1-3T7, which allows prospective examination of the onset of spontaneous immortalization and tumorigenicity. We documented the accumulation of cytogenomic aberrations in CKB1-3T7 over 24 months in continuous culture. The majority of aberrations emerged in parallel with key phenotypic changes in cell morphology, growth kinetics, and tumor incidence and latency. Focal deletion of CDKN2A/B emerged first, preceding the onset and progression of tumorigenic potential, and progressed to a homozygous deletion across the cell population during extended culture. Interestingly, CKB1-3T7 demonstrated a tumorigenic phenotype in vivo prior to exhibiting loss of contact inhibition in vitro. We also performed the first genome-wide characterization of the canine tumorigenic cell line MDCK, which also exhibited CDKN2A/B deletion. MDCK and CKB1-3T7 cells shared several additional aberrations that we have reported previously as being highly recurrent in spontaneous canine cancers, many of which, as with CDKN2A/B deletion, are evolutionarily conserved in their human counterparts. The conservation of these molecular events across multiple species, in vitro and in vivo, despite their contrasting karyotypic architecture, is a powerful indicator of a common mechanism underlying emerging neoplastic activity. Through integrated cytogenomic and phenotypic characterization of serial passages of CKB1-3T7 from initiation to development of a tumorigenic phenotype, we present a robust and readily accessible model (to be made available through the American Type Culture Collection) of spontaneous neoplastic transformation that overcomes many of the limitations of earlier studies. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10577-015-9474-8) contains supplementary material, which is available to authorized users

Phase Equilibria and Toughness of Zirconia-Based Thermal Barrier Coatings

Thermal barrier coating (TBC) systems are critical to the performance of gas turbine engines in the aviation and power generation industries. As engine operating temperatures are increased to improve efficiency, ceramic topcoats that depend on a metastable tetragonal phase, namely t’-8YSZ (ZrO2 + 8 ± 0.5 mol% YO1.5), rapidly degrade. Alternative TBC compositions that exhibit combinations of properties superior to 8YSZ are needed to meet the efficiency targets of next generation gas turbines. In this work, two approaches are pursued based on either a single-phase, non-transformable tetragonal structure or multiphase compositions that offer the possibility of adequate toughness and resistance to molten silicates. Previous laboratory investigations of the CeO2-TiO2-ZrO2 (CeTiSZ) system revealed a relatively large, non-transformable tetragonal field with exceptional tetragonality is stable at 1350°C. In the present work, challenges with transitioning the earlier laboratory results to industrial scale coatings are elucidated. Two important effects not previously encountered in the deposition of current TBCs are identified. Understanding the driving force for segregation during deposition as well as the potential reducibility of the cations upon heating is critical to maintaining stable phase equilibria in thermally sprayed coatings. The reduction of cerium (IV) upon heating places an inherent limit on the temperature capabilities of CeTiSZ coatings. Contrary to the CeTiSZ system, the ZrO2-YO1.5-TaO2.5 (ZYTO) system does not experience reduction of the cations at high temperatures. A stable, non-transformable tetragonal phase exists at temperatures up to 1500°C, albeit in a much narrower composition range. Although the ZrO2-rich region of the ternary had been studied previously, there was a paucity of information on the phase equilibria in the rest of the diagram. Systematic investigation of the entire YO1.5-TaO2.5 binary phase diagram elucidates the equilibrium phases and serves as a solid foundation for the investigation of the ZYTO ternary. For the first time, isothermal sections of the complete ZYTO ternary are experimentally determined at 1250°C and 1500°C. Two-phase fields in the ZYTO ternary suggest that multiphase compositions with improved combinations of properties may be possible. Specifically, a large two-phase field in which fluorite and YTaO4 (YT) are stable offers the potential to increase the toughness of fluorite, which, with sufficient rare earth content, can mitigate damage caused by molten silicates. Additionally incorporating YT as a second phase has the potential to improve the CMAS resistance of phase stable tetragonal compositions. Similar to the phase equilibria, there was a dearth of information on the toughness values and associated toughening mechanisms of compositions in the ZrO2-lean portion of the ZYTO phase diagram. Micro-indentation and micro-3-point bend experiments indicate that YT contributes to the toughness of multiphase samples. It is shown for the first time that samples containing YT exhibit microstructural features clearly consistent with domain wall motion, the fundamental mechanism underpinning ferroelastic toughening

Indium and Antimony Distribution in a Sphalerite from the “Burgstaetter Gangzug” of the Upper Harz Mountains Pb-Zn Mineralization

The sphalerite from the Burgstaetter Gangzug, a vein system of the Upper Harz Mountain nearby the town of Clausthal-Zellerfeld, exhibits a very interesting and partly complementary incorporation pattern of Cu, In and Sb, which has not yet been reported for natural sphalerite. A sphalerite specimen was characterized with electron probe micro-analysis (EPMA) and atom probe tomography (APT). Based on the EPMA results and a multilinear regression, a relation expressed as Cu = 0.98In + 1.81Sb + 0.03 can be calculated to describe the correlation between the elements. This indicates, that the incorporation mechanisms of In and Sb in the structure differ substantially. Indium is incorporated with the ratio Cu:In = 1:1 like in roquesite (CuInS2), supporting the coupled substitution mechanism 2Zn2+ → Cu+ + In3+. In contrast, Sb is incorporated with a ratio of Cu:Sb = 1.81:1. APT, which has a much higher spatial resolution indicates a ratio of Cu: Sb = 2.28: 1 in the entire captured volume, which is similar to the ratio calculated by EPMA, yet with inhomogeneities at the nanometer-scale. Analysis of the solute distribution shows two distinct sizes of clusters that are rich in Cu, Sb and Ag

A versatile cryo-transfer system, connecting cryogenic focused ion beam sample preparation to atom probe microscopy.

Atom probe tomography (APT) is a powerful technique to obtain 3D chemical and structural information, however the 'standard' atom probe experimental workflow involves transfer of specimens at ambient conditions. The ability to transfer air- or thermally-sensitive samples between instruments while maintaining environmental control is critical to prevent chemical or morphological changes prior to analysis for a variety of interesting sample materials. In this article, we describe a versatile transfer system that enables cryogenic- or room-temperature transfer of specimens in vacuum or atmospheric conditions between sample preparation stations, a focused ion beam system (Zeiss Crossbeam 540) and a widely used commercial atom probe system (CAMECA LEAP 4000X HR). As an example for the use of this transfer system, we present atom probe data of gallium- (Ga)-free grain boundaries in an aluminum (Al) alloy specimen prepared with a Ga-based FIB

Paramelaconite‐Enriched Copper‐Based Material as an Efficient and Robust Catalyst for Electrochemical Carbon Dioxide Reduction

A copper‐oxide‐based catalyst enriched with paramelaconite (Cu4O3) is presented and investigated as an electrocatalyst for facilitating electroreduction of CO2 to ethylene and other hydrocarbons. Cu4O3 is a member of the copper‐oxide family and possesses an intriguing mixed‐valance nature, incorporating an equal number of Cu+ and Cu2+ ions in its crystal structure. The material is synthesized using a solvothermal synthesis route and its structure is confirmed via powder X‐ray diffraction, transmission electron microscope based selected area electron diffraction, and X‐ray photoelectron spectroscopy. A flow reactor equipped with a gas diffusion electrode is utilized to test a copper‐based catalyst enriched with the Cu4O3 phase under CO2 reduction conditions. The Cu4O3‐rich catalyst (PrC) shows a Faradaic efficiency for ethylene over 40% at 400 mA cm−2. At −0.64 versus reversible hydrogen electrode, the highest C2+/C1 product ratio of 4.8 is achieved, with C2+ Faradaic efficiency over 61%. Additionally, the catalyst exhibits a stable performance for 24 h at a constant current density of 200 mA cm−2

Ag 2 Cu 2 O 3 – a catalyst template material for selective electroreduction of CO to C 2+ products

Although recent years have brought significant progress within the field of electrochemical conversion of CO2 and CO to value-added chemicals, many more challenges need to be overcome for this technology to be implemented on an industrial level. Rational design of catalyst materials that would enable selective production of desired products at industrially relevant current densities (>200 mA cm−2) is most certainly one of them. Here, we introduce Ag2Cu2O3, a mixed-metal oxide, as a starting template material for efficient electroreduction of CO to C2+ products. By combining results from electrochemical real-time mass spectrometry (EC-RTMS), XRD and XPS we confirmed the template nature of Ag2Cu2O3 and in situ formation of a fully reduced CuAg bimetallic material during the first minutes of electrolysis. Electrochemical screening of the catalyst revealed significantly varying product distributions when CO2 (CO2RR) and CO (CORR) where used as feed gases. During CORR, a faradaic efficiency close to 92% towards C2+ products at 600 mA cm−2 was achieved. On the other hand, during CO2RR, CO was found to be the main product under all tested current densities, reaching a maximum faradaic efficiency of 68%. XPS valence band spectra of the bimetallic surface originating from Ag2Cu2O3 showed that its d-band electronic structure is noticeably different compared to metallic Ag and Cu, a finding we link to the observed product distributions. Finally, additional microscopy characterization techniques were used to investigate the observed surface reconstruction of the catalyst material under reaction conditions